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* [gcc(refs/users/marxin/heads/sphinx-v2)] Add RST files with config files.
@ 2021-06-24 14:05 Martin Liska
0 siblings, 0 replies; 2+ messages in thread
From: Martin Liska @ 2021-06-24 14:05 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:dd815fa5289dd674dc865ff9ca6b5013a7ec182c
commit dd815fa5289dd674dc865ff9ca6b5013a7ec182c
Author: Martin Liska <mliska@suse.cz>
Date: Wed Jun 23 11:24:27 2021 +0200
Add RST files with config files.
Diff:
---
doc/Makefile | 97 +
doc/baseconf.py | 103 +
doc/bsd.rst | 39 +
doc/contrib.rst | 1277 ++++++
doc/contribute.rst | 26 +
doc/copyright.rst | 25 +
doc/cppdiropts.rst | 215 +
doc/cppenv.rst | 97 +
doc/cppopts.rst | 559 +++
doc/cppwarnopts.rst | 4 +
doc/funding.rst | 47 +
doc/gnu.rst | 24 +
doc/gnu_free_documentation_license.rst | 463 ++
doc/gpl-3.0.rst | 707 +++
doc/lgpl-2.1.rst | 512 +++
doc/md.rst | 3272 ++++++++++++++
gcc/doc/cpp/character-sets.rst | 56 +
gcc/doc/cpp/conditional-syntax.rst | 413 ++
gcc/doc/cpp/conditional-uses.rst | 32 +
gcc/doc/cpp/conditionals.rst | 44 +
gcc/doc/cpp/conf.py | 29 +
gcc/doc/cpp/copyright.rst | 1 +
gcc/doc/cpp/deleted-code.rst | 34 +
gcc/doc/cpp/diagnostics.rst | 57 +
gcc/doc/cpp/environment-variables.rst | 26 +
gcc/doc/cpp/gnu-free-documentation-license.rst | 6 +
| 57 +
.../alternatives-to-wrapper-#ifndef.rst | 40 +
| 88 +
| 67 +
| 42 +
| 58 +
| 53 +
| 41 +
| 62 +
gcc/doc/cpp/implementation-defined-behavior.rst | 99 +
gcc/doc/cpp/implementation-details.rst | 23 +
gcc/doc/cpp/implementation-limits.rst | 68 +
gcc/doc/cpp/index.rst | 34 +
gcc/doc/cpp/initial-processing.rst | 174 +
gcc/doc/cpp/invocation.rst | 85 +
gcc/doc/cpp/line-control.rst | 55 +
gcc/doc/cpp/macros.rst | 37 +
gcc/doc/cpp/macros/concatenation.rst | 91 +
.../macros/directives-within-macro-arguments.rst | 39 +
gcc/doc/cpp/macros/function-like-macros.rst | 55 +
gcc/doc/cpp/macros/macro-arguments.rst | 116 +
gcc/doc/cpp/macros/macro-pitfalls.rst | 457 ++
gcc/doc/cpp/macros/object-like-macros.rst | 130 +
gcc/doc/cpp/macros/predefined-macros.rst | 658 +++
gcc/doc/cpp/macros/stringizing.rst | 88 +
.../macros/undefining-and-redefining-macros.rst | 71 +
gcc/doc/cpp/macros/variadic-macros.rst | 145 +
gcc/doc/cpp/obsolete-features.rst | 100 +
gcc/doc/cpp/option-index.rst | 6 +
gcc/doc/cpp/other-directives.rst | 32 +
gcc/doc/cpp/overview.rst | 66 +
gcc/doc/cpp/pragmas.rst | 121 +
gcc/doc/cpp/preprocessor-output.rst | 86 +
gcc/doc/cpp/the-preprocessing-language.rst | 75 +
gcc/doc/cpp/tokenization.rst | 182 +
gcc/doc/cpp/traditional-lexical-analysis.rst | 74 +
gcc/doc/cpp/traditional-macros.rst | 99 +
gcc/doc/cpp/traditional-miscellany.rst | 30 +
gcc/doc/cpp/traditional-mode.rst | 35 +
gcc/doc/cpp/traditional-warnings.rst | 49 +
gcc/doc/cppinternals/conf.py | 23 +
gcc/doc/cppinternals/copyright.rst | 1 +
gcc/doc/cppinternals/cppinternals.rst | 435 ++
gcc/doc/cppinternals/cpplib.rst | 29 +
gcc/doc/cppinternals/files.rst | 70 +
gcc/doc/cppinternals/index.rst | 18 +
gcc/doc/cppinternals/indices-and-tables.rst | 6 +
.../internal-representation-of-macros.rst | 27 +
.../cppinternals/just-which-line-number-anyway.rst | 62 +
gcc/doc/cppinternals/lexing-a-line.rst | 91 +
gcc/doc/cppinternals/lexing-a-token.rst | 177 +
...-a-function-like-macros-opening-parenthesis.rst | 24 +
gcc/doc/cppinternals/macro-expansion-overview.rst | 51 +
...king-tokens-ineligible-for-future-expansion.rst | 24 +
gcc/doc/cppinternals/overview.rst | 24 +
.../representation-of-line-numbers.rst | 32 +
...g-the-replacement-list-for-macros-to-expand.rst | 57 +
gcc/doc/gcc/binary-compatibility.rst | 155 +
.../gcc/c++-implementation-defined-behavior.rst | 35 +
gcc/doc/gcc/c-implementation-defined-behavior.rst | 48 +
.../architecture.rst | 47 +
.../arrays-and-pointers.rst | 46 +
.../characters.rst | 101 +
.../declarators.rst | 14 +
.../environment.rst | 19 +
.../floating-point.rst | 87 +
.../c-implementation-defined-behavior/hints.rst | 35 +
.../identifiers.rst | 29 +
.../c-implementation-defined-behavior/integers.rst | 66 +
.../library-functions.rst | 19 +
.../locale-specific-behavior.rst | 12 +
.../preprocessing-directives.rst | 56 +
.../qualifiers.rst | 53 +
.../statements.rst | 14 +
...ructures-unions-enumerations-and-bit-fields.rst | 78 +
.../translation.rst | 21 +
gcc/doc/gcc/conditionally-supported-behavior.rst | 20 +
gcc/doc/gcc/conf.py | 36 +
gcc/doc/gcc/contributing-to-gcc-development.rst | 6 +
gcc/doc/gcc/contributors-to-gcc.rst | 6 +
gcc/doc/gcc/copyright.rst | 1 +
gcc/doc/gcc/exception-handling.rst | 15 +
gcc/doc/gcc/extensions-to-the-c++-language.rst | 36 +
.../backwards-compatibility.rst | 32 +
.../c++-concepts.rst | 44 +
.../c++-interface-and-implementation-pragmas.rst | 107 +
...cific-variable-function-and-type-attributes.rst | 99 +
.../deprecated-features.rst | 43 +
...ter-from-a-bound-pointer-to-member-function.rst | 52 +
.../function-multiversioning.rst | 65 +
.../restricting-pointer-aliasing.rst | 56 +
.../extensions-to-the-c++-language/type-traits.rst | 159 +
.../vague-linkage.rst | 86 +
.../when-is-a-volatile-c++-object-accessed.rst | 64 +
.../wheres-the-template.rst | 131 +
.../gcc/extensions-to-the-c-language-family.rst | 97 +
.../128-bit-integers.rst | 18 +
.../additional-floating-types.rst | 100 +
.../alternate-keywords.rst | 50 +
.../an-inline-function-is-as-fast-as-a-macro.rst | 142 +
.../arithmetic-on-void-and-function-pointers.rst | 29 +
.../arrays-of-length-zero.rst | 117 +
.../arrays-of-variable-length.rst | 107 +
.../attribute-syntax.rst | 259 ++
.../binary-constants-using-the-0b-prefix.rst | 29 +
...ns-for-memory-model-aware-atomic-operations.rst | 302 ++
...o-perform-arithmetic-with-overflow-checking.rst | 122 +
| 22 +
.../case-ranges.rst | 43 +
.../cast-to-a-union-type.rst | 71 +
.../complex-numbers.rst | 72 +
.../compound-literals.rst | 112 +
.../conditionals-with-omitted-operands.rst | 49 +
.../constructing-function-calls.rst | 127 +
.../decimal-floating-types.rst | 65 +
.../declaring-attributes-of-functions.rst | 115 +
.../aarch64-function-attributes.rst | 192 +
.../amd-gcn-function-attributes.rst | 93 +
.../arc-function-attributes.rst | 94 +
.../arm-function-attributes.rst | 172 +
.../avr-function-attributes.rst | 122 +
.../blackfin-function-attributes.rst | 105 +
.../bpf-function-attributes.rst | 24 +
.../c-sky-function-attributes.rst | 39 +
.../common-function-attributes.rst | 1811 ++++++++
.../cr16-function-attributes.rst | 20 +
.../epiphany-function-attributes.rst | 86 +
.../h8-300-function-attributes.rst | 41 +
.../ia-64-function-attributes.rst | 36 +
.../m32c-function-attributes.rst | 75 +
.../m32r-d-function-attributes.rst | 44 +
.../m68k-function-attributes.rst | 32 +
.../mcore-function-attributes.rst | 24 +
.../mep-function-attributes.rst | 53 +
.../microblaze-function-attributes.rst | 50 +
.../microsoft-windows-function-attributes.rst | 108 +
.../mips-function-attributes.rst | 146 +
.../msp430-function-attributes.rst | 107 +
.../nds32-function-attributes.rst | 100 +
.../nios-ii-function-attributes.rst | 44 +
.../nvidia-ptx-function-attributes.rst | 22 +
.../powerpc-function-attributes.rst | 229 +
.../risc-v-function-attributes.rst | 43 +
.../rl78-function-attributes.rst | 39 +
.../rx-function-attributes.rst | 75 +
.../s-390-function-attributes.rst | 52 +
.../sh-function-attributes.rst | 103 +
.../symbian-os-function-attributes.rst | 12 +
.../v850-function-attributes.rst | 22 +
.../visium-function-attributes.rst | 20 +
.../x86-function-attributes.rst | 983 ++++
.../xstormy16-function-attributes.rst | 20 +
.../designated-initializers.rst | 153 +
...e-alignment-of-functions-types-or-variables.rst | 48 +
.../dollar-signs-in-identifier-names.rst | 20 +
.../double-word-integers.rst | 43 +
.../enumerator-attributes.rst | 45 +
.../fixed-point-types.rst | 198 +
...ecks-specific-to-particular-target-machines.rst | 47 +
.../function-names-as-strings.rst | 75 +
...g-the-return-or-frame-address-of-a-function.rst | 97 +
.../half-precision-floating-point.rst | 60 +
.../hex-floats.rst | 30 +
...w-to-use-inline-assembly-language-in-c-code.rst | 1865 ++++++++
.../incomplete-enum-types.rst | 23 +
.../label-attributes.rst | 65 +
.../labels-as-values.rst | 93 +
...built-in-functions-for-atomic-memory-access.rst | 185 +
.../locally-declared-labels.rst | 84 +
.../macros-with-a-variable-number-of-arguments.rst | 74 +
.../mixed-declarations-labels-and-code.rst | 31 +
.../named-address-spaces.rst | 231 +
.../nested-functions.rst | 136 +
.../non-constant-initializers.rst | 25 +
.../non-lvalue-arrays-may-have-subscripts.rst | 34 +
.../nonlocal-gotos.rst | 62 +
.../object-size-checking-built-in-functions.rst | 167 +
.../other-built-in-functions-provided-by-gcc.rst | 2018 +++++++++
.../pointer-arguments-in-variadic-functions.rst | 24 +
...-to-arrays-with-qualifiers-work-as-expected.rst | 29 +
.../pragmas-accepted-by-gcc.rst | 719 +++
...ototypes-and-old-style-function-definitions.rst | 67 +
.../referring-to-a-type-with-typeof.rst | 149 +
.../slightly-looser-rules-for-escaped-newlines.rst | 25 +
.../specifying-attributes-of-types.rst | 704 +++
.../specifying-attributes-of-variables.rst | 1123 +++++
.../statement-attributes.rst | 46 +
.../statements-and-declarations-in-expressions.rst | 170 +
.../structures-with-no-members.rst | 24 +
.../support-for-offsetof.rst | 34 +
.../target-builtins.rst | 55 +
.../target-builtins/aarch64-built-in-functions.rst | 24 +
.../target-builtins/alpha-built-in-functions.rst | 88 +
.../altera-nios-ii-built-in-functions.rst | 118 +
.../target-builtins/arc-built-in-functions.rst | 232 +
.../arc-simd-built-in-functions.rst | 243 +
.../arm-armv8-m-security-extensions.rst | 35 +
.../arm-c-language-extensions-acle.rst | 30 +
...loating-point-status-and-control-intrinsics.rst | 17 +
.../arm-iwmmxt-built-in-functions.rst | 159 +
.../target-builtins/avr-built-in-functions.rst | 99 +
.../basic-powerpc-built-in-functions.rst | 728 +++
.../blackfin-built-in-functions.rst | 20 +
.../target-builtins/bpf-built-in-functions.rst | 23 +
.../target-builtins/fr-v-built-in-functions.rst | 231 +
.../mips-dsp-built-in-functions.rst | 299 ++
.../mips-loongson-built-in-functions.rst | 423 ++
.../target-builtins/mips-paired-single-support.rst | 44 +
.../mips-simd-architecture-msa-support.rst | 812 ++++
.../target-builtins/msp430-built-in-functions.rst | 33 +
.../target-builtins/nds32-built-in-functions.rst | 44 +
.../other-mips-built-in-functions.rst | 24 +
.../picochip-built-in-functions.rst | 39 +
.../powerpc-altivec-vsx-built-in-functions.rst | 1871 ++++++++
.../powerpc-atomic-memory-operation-functions.rst | 68 +
...are-transactional-memory-built-in-functions.rst | 226 +
...c-matrix-multiply-assist-built-in-functions.rst | 101 +
.../target-builtins/pru-built-in-functions.rst | 31 +
.../target-builtins/risc-v-built-in-functions.rst | 16 +
.../target-builtins/rx-built-in-functions.rst | 122 +
.../s-390-system-z-built-in-functions.rst | 121 +
.../target-builtins/sh-built-in-functions.rst | 50 +
.../sparc-vis-built-in-functions.rst | 226 +
.../target-builtins/ti-c6x-built-in-functions.rst | 43 +
.../target-builtins/tile-gx-built-in-functions.rst | 37 +
.../target-builtins/tilepro-built-in-functions.rst | 39 +
.../target-builtins/x86-built-in-functions.rst | 1643 +++++++
.../x86-control-flow-protection-intrinsics.rst | 50 +
.../x86-transactional-memory-intrinsics.rst | 102 +
.../the-character-esc-in-constants.rst | 12 +
.../thread-local-storage.rst | 223 +
.../unnamed-structure-and-union-fields.rst | 88 +
...tor-instructions-through-built-in-functions.rst | 285 ++
.../when-is-a-volatile-object-accessed.rst | 92 +
...y-model-extensions-for-transactional-memory.rst | 38 +
gcc/doc/gcc/funding.rst | 6 +
gcc/doc/gcc/gcc-command-options.rst | 71 +
gcc/doc/gcc/gcc-command-options/c++-modules.rst | 361 ++
.../gcc-command-options/compiling-c++-programs.rst | 46 +
gcc/doc/gcc/gcc-command-options/description.rst | 83 +
.../environment-variables-affecting-gcc.rst | 163 +
.../gcc-command-options/gcc-developer-options.rst | 1155 +++++
.../machine-dependent-options.rst | 100 +
.../machine-dependent-options/aarch64-options.rst | 482 ++
.../adapteva-epiphany-options.rst | 161 +
.../machine-dependent-options/amd-gcn-options.rst | 37 +
.../machine-dependent-options/arc-options.rst | 749 ++++
.../machine-dependent-options/arm-options.rst | 1010 +++++
.../machine-dependent-options/avr-options.rst | 640 +++
.../machine-dependent-options/blackfin-options.rst | 225 +
.../machine-dependent-options/c-sky-options.rst | 191 +
.../machine-dependent-options/c6x-options.rst | 53 +
.../machine-dependent-options/cr16-options.rst | 42 +
.../machine-dependent-options/cris-options.rst | 113 +
.../machine-dependent-options/darwin-options.rst | 166 +
.../dec-alpha-options.rst | 272 ++
.../machine-dependent-options/ebpf-options.rst | 45 +
.../machine-dependent-options/fr30-options.rst | 25 +
.../machine-dependent-options/frv-options.rst | 277 ++
.../machine-dependent-options/ft32-options.rst | 42 +
.../gnu-linux-options.rst | 54 +
.../machine-dependent-options/h8-300-options.rst | 61 +
.../machine-dependent-options/hppa-options.rst | 243 +
.../machine-dependent-options/ia-64-options.rst | 259 ++
.../ibm-rs-6000-and-powerpc-options.rst | 1011 +++++
.../machine-dependent-options/lm32-options.rst | 33 +
.../machine-dependent-options/m32c-options.rst | 36 +
.../machine-dependent-options/m32r-d-options.rst | 135 +
.../machine-dependent-options/m680x0-options.rst | 375 ++
.../machine-dependent-options/mcore-options.rst | 64 +
.../machine-dependent-options/mep-options.rst | 165 +
.../microblaze-options.rst | 118 +
.../machine-dependent-options/mips-options.rst | 974 ++++
.../machine-dependent-options/mmix-options.rst | 73 +
.../machine-dependent-options/mn10300-options.rst | 91 +
.../machine-dependent-options/moxie-options.rst | 29 +
.../machine-dependent-options/msp430-options.rst | 184 +
.../machine-dependent-options/nds32-options.rst | 114 +
.../machine-dependent-options/nios-ii-options.rst | 365 ++
.../nvidia-ptx-options.rst | 73 +
.../machine-dependent-options/openrisc-options.rst | 84 +
.../options-for-system-v.rst | 41 +
.../machine-dependent-options/pdp-11-options.rst | 71 +
.../machine-dependent-options/picochip-options.rst | 53 +
.../machine-dependent-options/powerpc-options.rst | 13 +
.../machine-dependent-options/pru-options.rst | 61 +
.../machine-dependent-options/risc-v-options.rst | 192 +
.../machine-dependent-options/rl78-options.rst | 89 +
.../machine-dependent-options/rx-options.rst | 203 +
.../s-390-and-zseries-options.rst | 241 +
.../machine-dependent-options/score-options.rst | 49 +
.../machine-dependent-options/sh-options.rst | 442 ++
.../solaris-2-options.rst | 40 +
.../machine-dependent-options/sparc-options.rst | 385 ++
.../machine-dependent-options/tile-gx-options.rst | 39 +
.../machine-dependent-options/tilepro-options.rst | 24 +
.../machine-dependent-options/v850-options.rst | 205 +
.../machine-dependent-options/vax-options.rst | 28 +
.../machine-dependent-options/visium-options.rst | 71 +
.../machine-dependent-options/vms-options.rst | 36 +
.../machine-dependent-options/vxworks-options.rst | 43 +
.../machine-dependent-options/x86-options.rst | 1496 +++++++
.../x86-windows-options.rst | 95 +
.../xstormy16-options.rst | 17 +
.../machine-dependent-options/xtensa-options.rst | 128 +
.../machine-dependent-options/zseries-options.rst | 13 +
gcc/doc/gcc/gcc-command-options/option-summary.rst | 1340 ++++++
.../options-controlling-c++-dialect.rst | 1935 ++++++++
.../options-controlling-c-dialect.rst | 496 +++
...ling-objective-c-and-objective-c++-dialects.rst | 319 ++
.../options-controlling-the-kind-of-output.rst | 729 +++
.../options-controlling-the-preprocessor.rst | 81 +
.../options-for-code-generation-conventions.rst | 714 +++
.../options-for-debugging-your-program.rst | 475 ++
.../options-for-directory-search.rst | 106 +
.../gcc-command-options/options-for-linking.rst | 411 ++
.../options-that-control-optimization.rst | 4678 ++++++++++++++++++++
.../options-that-control-static-analysis.rst | 563 +++
...s-to-control-diagnostic-messages-formatting.rst | 831 ++++
.../options-to-request-or-suppress-warnings.rst | 4504 +++++++++++++++++++
.../passing-options-to-the-assembler.rst | 27 +
.../program-instrumentation-options.rst | 941 ++++
...bprocesses-and-the-switches-to-pass-to-them.rst | 688 +++
| 136 +
gcc/doc/gcc/gcc.rst | 47 +
gcc/doc/gcc/gcov-dump.rst | 52 +
gcc/doc/gcc/gcov-tool.rst | 154 +
gcc/doc/gcc/gcov.rst | 25 +
.../gcov/brief-description-of-gcov-data-files.rst | 33 +
...-file-relocation-to-support-cross-profiling.rst | 43 +
gcc/doc/gcc/gcov/introduction-to-gcov.rst | 62 +
gcc/doc/gcc/gcov/invoking-gcov.rst | 656 +++
.../gcc/gcov/using-gcov-with-gcc-optimization.rst | 86 +
gcc/doc/gcc/general-public-license-3.rst | 6 +
gcc/doc/gcc/gnu-free-documentation-license.rst | 6 +
gcc/doc/gcc/gnu-objective-c-features.rst | 29 +
.../compatibilityalias.rst | 28 +
.../constant-string-objects.rst | 66 +
.../gcc/gnu-objective-c-features/exceptions.rst | 81 +
.../gnu-objective-c-features/fast-enumeration.rst | 223 +
.../garbage-collection.rst | 83 +
.../gnu-objective-c-runtime-api.rst | 100 +
.../load-executing-code-before-main.rst | 141 +
.../messaging-with-the-gnu-objective-c-runtime.rst | 145 +
.../gnu-objective-c-features/synchronization.rst | 38 +
.../gcc/gnu-objective-c-features/type-encoding.rst | 242 +
gcc/doc/gcc/gnu.rst | 1 +
gcc/doc/gcc/have-you-found-a-bug.rst | 70 +
gcc/doc/gcc/how-and-where-to-report-bugs.rst | 13 +
gcc/doc/gcc/how-to-get-help-with-gcc.rst | 26 +
gcc/doc/gcc/index.rst | 39 +
gcc/doc/gcc/known-causes-of-trouble-with-gcc.rst | 36 +
.../actual-bugs-we-havent-fixed-yet.rst | 14 +
.../certain-changes-we-dont-want-to-make.rst | 242 +
.../common-misunderstandings-with-gnu-c.rst | 311 ++
.../disappointments-and-misunderstandings.rst | 105 +
| 39 +
.../incompatibilities-of-gcc.rst | 255 ++
.../interoperation.rst | 153 +
.../standard-libraries.rst | 33 +
.../warning-messages-and-error-messages.rst | 52 +
.../gcc/language-standards-supported-by-gcc.rst | 23 +
.../c++-language.rst | 71 +
.../c-language.rst | 232 +
.../d-language.rst | 11 +
.../go-language.rst | 10 +
.../objective-c-and-objective-c++-languages.rst | 64 +
.../references-for-other-languages.rst | 13 +
gcc/doc/gcc/lto-dump.rst | 92 +
gcc/doc/gcc/option-index.rst | 11 +
.../gcc/programming-languages-supported-by-gcc.rst | 82 +
gcc/doc/gcc/reporting-bugs.rst | 25 +
.../analysis-and-optimization-of-gimple-tuples.rst | 46 +
.../alias-analysis.rst | 108 +
.../annotations.rst | 17 +
.../memory-model.rst | 34 +
.../ssa-operands.rst | 396 ++
.../static-single-assignment.rst | 264 ++
.../analysis-and-representation-of-loops.rst | 27 +
.../data-dependency-analysis.rst | 135 +
.../iv-analysis-on-rtl.rst | 55 +
.../loop-closed-ssa-form.rst | 49 +
.../loop-manipulation.rst | 58 +
.../loop-querying.rst | 81 +
.../loop-representation.rst | 138 +
.../number-of-iterations-analysis.rst | 85 +
.../scalar-evolutions.rst | 73 +
gcc/doc/gccint/analyzer-internals.rst | 421 ++
gcc/doc/gccint/collect2.rst | 79 +
gcc/doc/gccint/conf.py | 23 +
gcc/doc/gccint/contributing-to-gcc-development.rst | 6 +
gcc/doc/gccint/contributors-to-gcc.rst | 6 +
gcc/doc/gccint/control-flow-graph.rst | 45 +
gcc/doc/gccint/control-flow-graph/basic-blocks.rst | 149 +
gcc/doc/gccint/control-flow-graph/edges.rst | 251 ++
.../control-flow-graph/liveness-information.rst | 53 +
.../control-flow-graph/maintaining-the-cfg.rst | 155 +
.../control-flow-graph/profile-information.rst | 116 +
gcc/doc/gccint/copyright.rst | 1 +
gcc/doc/gccint/debugging-the-analyzer.rst | 110 +
gcc/doc/gccint/funding.rst | 6 +
gcc/doc/gccint/gcc-and-portability.rst | 47 +
gcc/doc/gccint/general-public-license-3.rst | 6 +
gcc/doc/gccint/generic.rst | 51 +
gcc/doc/gccint/generic/attributes-in-trees.rst | 39 +
gcc/doc/gccint/generic/c-and-c++-trees.rst | 1026 +++++
gcc/doc/gccint/generic/declarations.rst | 384 ++
gcc/doc/gccint/generic/deficiencies.rst | 18 +
gcc/doc/gccint/generic/expressions.rst | 1142 +++++
gcc/doc/gccint/generic/functions.rst | 228 +
.../gccint/generic/language-dependent-trees.rst | 25 +
gcc/doc/gccint/generic/overview.rst | 239 +
gcc/doc/gccint/generic/statements.rst | 562 +++
gcc/doc/gccint/generic/types.rst | 387 ++
gcc/doc/gccint/gimple-api.rst | 58 +
gcc/doc/gccint/gimple.rst | 88 +
.../gimple/adding-a-new-gimple-statement-code.rst | 36 +
.../class-hierarchy-of-gimple-statements.rst | 150 +
gcc/doc/gccint/gimple/exception-handling.rst | 46 +
gcc/doc/gccint/gimple/gimple-instruction-set.rst | 46 +
gcc/doc/gccint/gimple/gimple-sequences.rst | 94 +
.../gimple/manipulating-gimple-statements.rst | 184 +
gcc/doc/gccint/gimple/operands.rst | 319 ++
gcc/doc/gccint/gimple/sequence-iterators.rst | 223 +
.../gimple/statement-and-operand-traversals.rst | 66 +
gcc/doc/gccint/gimple/temporaries.rst | 42 +
gcc/doc/gccint/gimple/tuple-representation.rst | 211 +
gcc/doc/gccint/gimple/tuple-specific-accessors.rst | 44 +
.../gimple/tuple-specific-accessors/gimpleasm.rst | 66 +
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.../gimple/tuple-specific-accessors/gimplebind.rst | 56 +
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.../tuple-specific-accessors/gimpleompparallel.rst | 76 +
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.../tuple-specific-accessors/gimpleswitch.rst | 52 +
.../gimple/tuple-specific-accessors/gimpletry.rst | 51 +
.../gimplewithcleanupexpr.rst | 30 +
gcc/doc/gccint/gnu-free-documentation-license.rst | 6 +
gcc/doc/gccint/guidelines-for-diagnostics.rst | 614 +++
gcc/doc/gccint/guidelines-for-options.rst | 17 +
gcc/doc/gccint/host-common.rst | 59 +
gcc/doc/gccint/host-configuration.rst | 32 +
gcc/doc/gccint/host-filesystem.rst | 105 +
gcc/doc/gccint/host-makefile-fragments.rst | 16 +
gcc/doc/gccint/host-misc.rst | 71 +
gcc/doc/gccint/index.rst | 74 +
gcc/doc/gccint/interfacing-to-gcc-output.rst | 85 +
gcc/doc/gccint/language-front-ends-in-gcc.rst | 39 +
gcc/doc/gccint/link-time-optimization.rst | 34 +
.../link-time-optimization/design-overview.rst | 124 +
.../internal-flags-controlling-lto1.rst | 44 +
.../link-time-optimization/lto-file-sections.rst | 110 +
.../using-summary-information-in-ipa-passes.rst | 206 +
...tions-linker-plugin-and-symbol-visibilities.rst | 91 +
gcc/doc/gccint/machine-descriptions.rst | 49 +
.../c-statements-for-assembler-output.rst | 128 +
.../canonicalization-of-instructions.rst | 169 +
.../machine-descriptions/conditional-execution.rst | 100 +
.../machine-descriptions/constant-definitions.rst | 185 +
.../defining-how-to-split-instructions.rst | 378 ++
.../defining-jump-instruction-patterns.rst | 39 +
.../defining-looping-instruction-patterns.rst | 136 +
.../defining-rtl-sequences-for-code-generation.rst | 211 +
.../everything-about-instruction-patterns.rst | 113 +
.../machine-descriptions/example-of-defineinsn.rst | 54 +
.../including-patterns-in-machine-descriptions.rst | 76 +
.../instruction-attributes.rst | 1360 ++++++
.../interdependence-of-patterns.rst | 45 +
gcc/doc/gccint/machine-descriptions/iterators.rst | 555 +++
.../machine-specific-peephole-optimizers.rst | 335 ++
.../machine-descriptions/operand-constraints.rst | 429 ++
.../output-templates-and-operand-substitution.rst | 107 +
...view-of-how-the-machine-description-is-used.rst | 47 +
gcc/doc/gccint/machine-descriptions/predicates.rst | 361 ++
.../gccint/machine-descriptions/rtl-template.rst | 263 ++
.../rtl-templates-transformations.rst | 225 +
.../standard-pattern-names-for-generation.rst | 3514 +++++++++++++++
.../when-the-order-of-patterns-matters.rst | 31 +
gcc/doc/gccint/makefile-fragments.rst | 37 +
gcc/doc/gccint/match-and-simplify.rst | 34 +
.../memory-management-and-type-information.rst | 97 +
.../how-to-invoke-the-garbage-collector.rst | 35 +
.../marking-roots-for-the-garbage-collector.rst | 30 +
.../source-files-containing-type-information.rst | 63 +
.../support-for-inheritance.rst | 59 +
...pport-for-user-provided-gc-marking-routines.rst | 121 +
.../the-inside-of-a-gty.rst | 304 ++
.../troubleshooting-the-garbage-collector.rst | 29 +
gcc/doc/gccint/option-file-format.rst | 149 +
gcc/doc/gccint/option-index.rst | 11 +
gcc/doc/gccint/option-properties.rst | 360 ++
gcc/doc/gccint/option-specification-files.rst | 23 +
.../gccint/passes-and-files-of-the-compiler.rst | 33 +
.../gimplification-pass.rst | 50 +
.../inter-procedural-optimization-passes.rst | 271 ++
.../optimization-info.rst | 262 ++
.../parsing-pass.rst | 96 +
.../pass-manager.rst | 42 +
.../rtl-passes.rst | 279 ++
.../tree-ssa-passes.rst | 477 ++
gcc/doc/gccint/plugins.rst | 35 +
gcc/doc/gccint/plugins/building-gcc-plugins.rst | 101 +
.../controlling-which-passes-are-being-run.rst | 16 +
.../plugins/giving-information-about-a-plugin.rst | 24 +
.../interacting-with-the-gcc-garbage-collector.rst | 37 +
.../plugins/interacting-with-the-pass-manager.rst | 57 +
.../plugins/keeping-track-of-available-passes.rst | 17 +
gcc/doc/gccint/plugins/loading-plugins.rst | 31 +
gcc/doc/gccint/plugins/plugin-api.rst | 213 +
.../recording-information-about-pass-execution.rst | 20 +
.../registering-custom-attributes-or-pragmas.rst | 73 +
gcc/doc/gccint/rtl-representation.rst | 52 +
.../rtl-representation/access-to-operands.rst | 85 +
.../access-to-special-operands.rst | 192 +
.../assembler-instructions-as-expressions.rst | 47 +
gcc/doc/gccint/rtl-representation/bit-fields.rst | 50 +
.../rtl-representation/comparison-operations.rst | 140 +
.../constant-expression-types.rst | 325 ++
gcc/doc/gccint/rtl-representation/conversions.rst | 154 +
gcc/doc/gccint/rtl-representation/declarations.rst | 31 +
.../embedded-side-effects-on-addresses.rst | 106 +
.../flags-in-an-rtl-expression.rst | 625 +++
gcc/doc/gccint/rtl-representation/insns.rst | 650 +++
.../gccint/rtl-representation/machine-modes.rst | 663 +++
.../on-the-side-ssa-form-for-rtl.rst | 774 ++++
gcc/doc/gccint/rtl-representation/reading-rtl.rst | 34 +
.../rtl-representation/registers-and-memory.rst | 471 ++
.../rtl-representation/rtl-classes-and-formats.rst | 198 +
.../rtl-expressions-for-arithmetic.rst | 434 ++
.../gccint/rtl-representation/rtl-object-types.rst | 102 +
.../rtl-representation-of-function-call-insns.rst | 76 +
.../rtl-representation/side-effect-expressions.rst | 380 ++
.../structure-sharing-assumptions.rst | 105 +
.../variable-location-debug-information-in-rtl.rst | 64 +
.../rtl-representation/vector-operations.rst | 60 +
.../sizes-and-offsets-as-runtime-invariants.rst | 53 +
.../alignment-of-polyints.rst | 82 +
.../arithmetic-on-polyints.rst | 178 +
.../comparisons-involving-polyint.rst | 321 ++
.../computing-bounds-on-polyints.rst | 34 +
.../consequences-of-using-polyint.rst | 55 +
.../converting-polyints.rst | 91 +
.../guidelines-for-using-polyint.rst | 123 +
.../miscellaneous-polyint-routines.rst | 16 +
.../overview-of-polyint.rst | 80 +
.../source-tree-structure-and-build-system.rst | 21 +
.../configure-terms-and-history.rst | 66 +
.../the-gcc-subdirectory.rst | 28 +
.../anatomy-of-a-language-front-end.rst | 286 ++
.../anatomy-of-a-target-back-end.rst | 116 +
.../build-system-in-the-gcc-directory.rst | 14 +
.../building-documentation.rst | 168 +
.../configuration-in-the-gcc-directory.rst | 128 +
| 49 +
...e-files-and-headers-under-the-gcc-directory.rst | 15 +
.../the-gcc-subdirectory/makefile-targets.rst | 192 +
.../the-gcc-subdirectory/subdirectories-of-gcc.rst | 56 +
.../top-level-source-directory.rst | 116 +
.../gccint/standard-header-file-directories.rst | 35 +
gcc/doc/gccint/static-analyzer.rst | 21 +
gcc/doc/gccint/target-macros.rst | 66 +
.../adding-support-for-named-address-spaces.rst | 163 +
gcc/doc/gccint/target-macros/addressing-modes.rst | 830 ++++
.../adjusting-the-instruction-scheduler.rst | 660 +++
.../gccint/target-macros/anchored-addresses.rst | 94 +
.../gccint/target-macros/c++-abi-parameters.rst | 164 +
.../gccint/target-macros/condition-code-status.rst | 212 +
.../controlling-debugging-information-format.rst | 490 ++
.../controlling-the-compilation-driver-gcc.rst | 484 ++
.../cross-compilation-and-floating-point.rst | 75 +
gcc/doc/gccint/target-macros/d-abi-parameters.rst | 107 +
...ning-coprocessor-specifics-for-mips-targets.rst | 35 +
...ata-structures-for-per-function-information.rst | 64 +
.../defining-target-specific-uses-of-attribute.rst | 284 ++
.../defining-the-output-assembler-language.rst | 27 +
.../assembler-commands-for-alignment.rst | 95 +
.../assembler-commands-for-exception-regions.rst | 188 +
.../how-initialization-functions-are-handled.rst | 130 +
.../macros-controlling-initialization-routines.rst | 170 +
.../output-and-generation-of-labels.rst | 586 +++
.../output-of-assembler-instructions.rst | 255 ++
.../output-of-data.rst | 196 +
.../output-of-dispatch-tables.rst | 171 +
.../output-of-uninitialized-variables.rst | 105 +
.../the-overall-framework-of-an-assembler-file.rst | 287 ++
.../describing-relative-costs-of-operations.rst | 532 +++
...ividing-the-output-into-sections-texts-data.rst | 443 ++
gcc/doc/gccint/target-macros/emulating-tls.rst | 125 +
.../implementing-the-varargs-macros.rst | 237 +
.../implicit-calls-to-library-routines.rst | 147 +
.../layout-of-source-language-data-types.rst | 381 ++
.../target-macros/miscellaneous-parameters.rst | 1658 +++++++
.../target-macros/mode-switching-instructions.rst | 121 +
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.../target-macros/position-independent-code.rst | 55 +
gcc/doc/gccint/target-macros/register-classes.rst | 807 ++++
gcc/doc/gccint/target-macros/register-usage.rst | 595 +++
.../run-time-target-specification.rst | 259 ++
.../stack-layout-and-calling-conventions.rst | 35 +
.../basic-stack-layout.rst | 300 ++
.../caller-saves-register-allocation.rst | 21 +
.../eliminating-frame-pointer-and-arg-pointer.rst | 102 +
.../exception-handling-support.rst | 137 +
.../function-entry-and-exit.rst | 274 ++
.../generating-code-for-profiling.rst | 61 +
.../how-large-values-are-returned.rst | 138 +
.../how-scalar-function-values-are-returned.rst | 170 +
.../miscellaneous-register-hooks.rst | 26 +
.../passing-arguments-in-registers.rst | 643 +++
.../passing-function-arguments-on-the-stack.rst | 197 +
.../permitting-tail-calls.rst | 60 +
.../registers-that-address-the-stack-frame.rst | 202 +
.../shrink-wrapping-separate-components.rst | 93 +
.../specifying-how-stack-checking-is-done.rst | 118 +
.../stack-smashing-protection.rst | 75 +
gcc/doc/gccint/target-macros/storage-layout.rst | 722 +++
.../target-macros/support-for-nested-functions.rst | 228 +
.../target-macros/the-global-targetm-variable.rst | 67 +
gcc/doc/gccint/target-makefile-fragments.rst | 247 ++
gcc/doc/gccint/testsuites.rst | 29 +
.../gccint/testsuites/ada-language-testsuites.rst | 38 +
.../gccint/testsuites/c-language-testsuites.rst | 113 +
.../directives-used-within-dejagnu-tests.rst | 19 +
.../commands-for-use-in-dg-final.rst | 283 ++
.../features-for-dg-add-options.rst | 123 +
.../keywords-describing-target-attributes.rst | 1369 ++++++
.../selecting-targets-to-which-a-test-applies.rst | 106 +
.../syntax-and-descriptions-of-test-directives.rst | 311 ++
.../variants-of-dg-require-support.rst | 83 +
.../testsuites/idioms-used-in-testsuite-code.rst | 84 +
.../support-for-testing-binary-compatibility.rst | 109 +
.../gccint/testsuites/support-for-testing-gcov.rst | 72 +
.../support-for-testing-gimple-passes.rst | 55 +
...support-for-testing-link-time-optimizations.rst | 46 +
...-for-testing-profile-directed-optimizations.rst | 52 +
.../testsuites/support-for-testing-rtl-passes.rst | 48 +
...-for-torture-testing-using-multiple-options.rst | 52 +
.../gccint/the-gcc-low-level-runtime-library.rst | 49 +
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...utines-for-decimal-floating-point-emulation.rst | 470 ++
...utines-for-fixed-point-fractional-emulation.rst | 2687 +++++++++++
.../routines-for-floating-point-emulation.rst | 371 ++
.../routines-for-integer-arithmetic.rst | 218 +
gcc/doc/gccint/the-language.rst | 384 ++
gcc/doc/gccint/user-experience-guidelines.rst | 32 +
gcc/doc/install/binaries.rst | 61 +
gcc/doc/install/building.rst | 65 +
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.../building/building-a-native-compiler.rst | 191 +
gcc/doc/install/building/building-in-parallel.rst | 15 +
.../install/building/building-the-ada-compiler.rst | 9 +
.../building/building-with-profile-feedback.rst | 36 +
gcc/doc/install/conf.py | 23 +
gcc/doc/install/configuration.rst | 2055 +++++++++
gcc/doc/install/copyright.rst | 1 +
gcc/doc/install/downloading-gcc.rst | 46 +
gcc/doc/install/final-installation.rst | 136 +
gcc/doc/install/gnu-free-documentation-license.rst | 6 +
...-target-specific-installation-notes-for-gcc.rst | 1363 ++++++
...can-you-run-the-testsuite-on-selected-tests.rst | 46 +
gcc/doc/install/how-to-interpret-test-results.rst | 32 +
gcc/doc/install/index.rst | 26 +
gcc/doc/install/indices-and-tables.rst | 6 +
gcc/doc/install/installing-gcc.rst | 41 +
...ing-options-and-running-multiple-testsuites.rst | 74 +
gcc/doc/install/prerequisites.rst | 280 ++
gcc/doc/install/submitting-test-results.rst | 24 +
gcc/doc/install/testing.rst | 73 +
.../code-that-interacts-with-the-user.rst | 19 +
.../doc/gfc-internals/command-line-options.rst | 35 +
gcc/fortran/doc/gfc-internals/conf.py | 26 +
gcc/fortran/doc/gfc-internals/copyright.rst | 1 +
gcc/fortran/doc/gfc-internals/error-handling.rst | 79 +
.../doc/gfc-internals/frontend-data-structures.rst | 26 +
...-the-intermediate-language-for-later-stages.rst | 24 +
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.../converting-expressions-to-tree.rst | 48 +
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gcc/fortran/doc/gfc-internals/gfccode.rst | 151 +
gcc/fortran/doc/gfc-internals/gfcexpr.rst | 162 +
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gcc/fortran/doc/gfc-internals/index.rst | 38 +
.../doc/gfc-internals/indices-and-tables.rst | 6 +
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gcc/fortran/doc/gfc-internals/introduction.rst | 22 +
.../doc/gfc-internals/symbol-versioning.rst | 69 +
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gcc/fortran/doc/gfortran/coarray-programming.rst | 17 +
.../doc/gfortran/compiler-characteristics.rst | 27 +
.../compiler-characteristics/asynchronous-i-o.rst | 29 +
.../data-consistency-and-durability.rst | 80 +
.../evaluation-of-logical-expressions.rst | 18 +
...file-format-of-unformatted-sequential-files.rst | 71 +
.../file-operations-on-symbolic-links.rst | 28 +
...pened-without-an-explicit-action=-specifier.rst | 23 +
...nternal-representation-of-logical-variables.rst | 24 +
.../kind-type-parameters.rst | 53 +
...-and-min-intrinsics-with-real-nan-arguments.rst | 21 +
.../thread-safety-of-the-runtime-library.rst | 53 +
gcc/fortran/doc/gfortran/conf.py | 32 +
gcc/fortran/doc/gfortran/contributing.rst | 29 +
.../doc/gfortran/contributors-to-gnu-fortran.rst | 111 +
gcc/fortran/doc/gfortran/copyright.rst | 1 +
.../extensions-implemented-in-gnu-fortran.rst | 1456 ++++++
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gcc/fortran/doc/gfortran/extensions.rst | 24 +
gcc/fortran/doc/gfortran/fortran-2003-status.rst | 206 +
gcc/fortran/doc/gfortran/fortran-2008-status.rst | 122 +
.../doc/gfortran/fortran-standards-status.rst | 16 +
.../doc/gfortran/function-abi-documentation.rst | 1526 +++++++
gcc/fortran/doc/gfortran/funding.rst | 6 +
.../doc/gfortran/general-public-license-3.rst | 6 +
.../doc/gfortran/gnu-fortran-command-options.rst | 38 +
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.../enable-and-customize-preprocessing.rst | 326 ++
.../environment-variables-affecting-gfortran.rst | 28 +
.../influencing-runtime-behavior.rst | 57 +
.../influencing-the-linking-step.rst | 26 +
.../gnu-fortran-command-options/option-summary.rst | 105 +
.../options-controlling-fortran-dialect.rst | 454 ++
.../options-for-code-generation-conventions.rst | 655 +++
...s-for-debugging-your-program-or-gnu-fortran.rst | 140 +
.../options-for-directory-search.rst | 82 +
...s-for-interoperability-with-other-languages.rst | 67 +
...-to-request-or-suppress-errors-and-warnings.rst | 518 +++
.../gfortran/gnu-fortran-compiler-directives.rst | 174 +
.../gfortran/gnu-free-documentation-license.rst | 6 +
gcc/fortran/doc/gfortran/index.rst | 43 +
.../doc/gfortran/interoperability-with-c.rst | 451 ++
gcc/fortran/doc/gfortran/intrinsic-modules.rst | 20 +
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.../doc/gfortran/intrinsic-modules/isocbinding.rst | 97 +
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.../intrinsic-modules/openacc-module-openacc.rst | 32 +
.../openmp-modules-omplib-and-omplibkinds.rst | 161 +
gcc/fortran/doc/gfortran/intrinsic-procedures.rst | 300 ++
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.../implementing-flush-construct.rst | 11 +
.../the-libgomp-abi/implementing-for-construct.rst | 73 +
.../implementing-master-construct.rst | 18 +
.../implementing-openaccs-parallel-construct.rst | 17 +
.../implementing-ordered-construct.rst | 14 +
.../implementing-parallel-construct.rst | 55 +
.../implementing-private-clause.rst | 17 +
.../implementing-reduction-clause.rst | 15 +
.../implementing-sections-construct.rst | 42 +
.../implementing-single-construct.rst | 48 +
.../implementing-threadprivate-construct.rst | 18 +
libiberty/doc/bsd.rst | 6 +
libiberty/doc/conf.py | 24 +
libiberty/doc/copyright.rst | 1 +
libiberty/doc/extensions.rst | 756 ++++
.../doc/function-variable-and-macro-listing.rst | 1865 ++++++++
libiberty/doc/index.rst | 28 +
libiberty/doc/indices-and-tables.rst | 6 +
.../doc/lesser-general-public-license-2.1.rst | 6 +
libiberty/doc/overview.rst | 20 +
libiberty/doc/replacement-functions.rst | 66 +
libiberty/doc/supplemental-functions.rst | 35 +
libiberty/doc/using.rst | 44 +
libitm/doc/c-c++-language-constructs-for-tm.rst | 43 +
libitm/doc/conf.py | 23 +
libitm/doc/copyright.rst | 1 +
libitm/doc/enabling-libitm.rst | 17 +
libitm/doc/gnu-free-documentation-license.rst | 6 +
libitm/doc/index.rst | 28 +
libitm/doc/indices-and-tables.rst | 6 +
libitm/doc/internals.rst | 16 +
libitm/doc/locking-conventions.rst | 268 ++
libitm/doc/nesting-flat-vs-closed.rst | 28 +
libitm/doc/the-libitm-abi.rst | 27 +
libitm/doc/the-libitm-abi/function-list.rst | 271 ++
.../future-enhancements-to-the-abi.rst | 7 +
.../the-libitm-abi/library-design-principles.rst | 61 +
libitm/doc/the-libitm-abi/memory-model.rst | 22 +
libitm/doc/the-libitm-abi/non-objectives.rst | 7 +
libitm/doc/the-libitm-abi/objectives.rst | 7 +
libitm/doc/the-libitm-abi/sample-code.rst | 10 +
.../doc/the-libitm-abi/types-and-macros-list.rst | 11 +
libitm/doc/tm-methods-and-method-groups.rst | 47 +
libquadmath/doc/conf.py | 23 +
libquadmath/doc/copyright.rst | 1 +
libquadmath/doc/gnu-free-documentation-license.rst | 6 +
libquadmath/doc/i-o-library-routines.rst | 15 +
libquadmath/doc/index.rst | 27 +
libquadmath/doc/indices-and-tables.rst | 6 +
libquadmath/doc/math-library-routines.rst | 108 +
libquadmath/doc/quadmathsnprintf.rst | 79 +
libquadmath/doc/reporting-bugs.rst | 20 +
libquadmath/doc/strtoflt128.rst | 40 +
libquadmath/doc/typedef-and-constants.rst | 47 +
1302 files changed, 176026 insertions(+)
diff --git a/doc/Makefile b/doc/Makefile
new file mode 100644
index 00000000000..9e305a8e7da
--- /dev/null
+++ b/doc/Makefile
@@ -0,0 +1,97 @@
+# Makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line.
+SPHINXOPTS ?= -j auto -q
+SPHINXBUILD ?= sphinx-build
+PAPER ?=
+SOURCEDIR = .
+BUILDDIR = _build
+
+# Internal variables.
+PAPEROPT_a4 = -D latex_elements.papersize=a4paper
+PAPEROPT_letter = -D latex_elements.papersize=letterpaper
+# $(O) is meant as a shortcut for $(SPHINXOPTS)
+ALLSPHINXOPTS = -d $(BUILDDIR)/doctrees $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) $(O) $(SOURCEDIR)
+# the i18n builder cannot share the environment and doctrees with the others
+I18NSPHINXOPTS = $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) $(O) $(SOURCEDIR)
+
+.PHONY: help
+help:
+ @echo "Please use \`make <target>' where <target> is one of"
+ @echo " html to make standalone HTML files"
+ @echo " dirhtml to make HTML files named index.html in directories"
+ @echo " singlehtml to make a single large HTML file"
+ @echo " pickle to make pickle files"
+ @echo " json to make JSON files"
+ @echo " htmlhelp to make HTML files and an HTML help project"
+ @echo " qthelp to make HTML files and a qthelp project"
+ @echo " applehelp to make an Apple Help Book"
+ @echo " devhelp to make HTML files and a Devhelp project"
+ @echo " epub to make an epub"
+ @echo " latex to make LaTeX files (you can set PAPER=a4 or PAPER=letter)"
+ @echo " latexpdf to make LaTeX files and then PDFs out of them"
+ @echo " latexpdfja to make LaTeX files and run them through platex/dvipdfmx"
+ @echo " lualatexpdf to make LaTeX files and run them through lualatex"
+ @echo " xelatexpdf to make LaTeX files and run them through xelatex"
+ @echo " text to make text files"
+ @echo " man to make manual pages"
+ @echo " texinfo to make Texinfo files"
+ @echo " info to make Texinfo files and run them through makeinfo"
+ @echo " gettext to make PO message catalogs"
+ @echo " changes to make an overview of all changed/added/deprecated items"
+ @echo " xml to make Docutils-native XML files"
+ @echo " pseudoxml to make pseudoxml-XML files for display purposes"
+ @echo " linkcheck to check all external links for integrity"
+ @echo " doctest to run all doctests embedded in the documentation (if enabled)"
+ @echo " coverage to run coverage check of the documentation (if enabled)"
+ @echo " dummy to check syntax errors of document sources"
+
+.PHONY: clean
+clean:
+ rm -rf $(BUILDDIR)
+
+.PHONY: latexpdf
+latexpdf:
+ $(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+ @echo "Running LaTeX files through pdflatex..."
+ $(MAKE) LATEXMKOPTS="-interaction=nonstopmode -f" -C $(BUILDDIR)/latex all-pdf
+ @echo "pdflatex finished; the PDF files are in $(BUILDDIR)/latex."
+
+.PHONY: latexpdfja
+latexpdfja:
+ $(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+ @echo "Running LaTeX files through platex and dvipdfmx..."
+ $(MAKE) -C $(BUILDDIR)/latex all-pdf-ja
+ @echo "pdflatex finished; the PDF files are in $(BUILDDIR)/latex."
+
+.PHONY: lualatexpdf
+lualatexpdf:
+ $(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+ @echo "Running LaTeX files through lualatex..."
+ $(MAKE) PDFLATEX=lualatex -C $(BUILDDIR)/latex all-pdf
+ @echo "lualatex finished; the PDF files are in $(BUILDDIR)/latex."
+
+.PHONY: xelatexpdf
+xelatexpdf:
+ $(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+ @echo "Running LaTeX files through xelatex..."
+ $(MAKE) PDFLATEX=xelatex -C $(BUILDDIR)/latex all-pdf
+ @echo "xelatex finished; the PDF files are in $(BUILDDIR)/latex."
+
+.PHONY: info
+info:
+ $(SPHINXBUILD) -b texinfo $(ALLSPHINXOPTS) $(BUILDDIR)/texinfo
+ @echo "Running Texinfo files through makeinfo..."
+ make -C $(BUILDDIR)/texinfo info
+ @echo "makeinfo finished; the Info files are in $(BUILDDIR)/texinfo."
+
+.PHONY: gettext
+gettext:
+ $(SPHINXBUILD) -b gettext $(I18NSPHINXOPTS) $(BUILDDIR)/locale
+
+# Catch-all target: route all unknown targets to Sphinx
+.PHONY: Makefile
+%: Makefile
+ $(SPHINXBUILD) -b "$@" $(ALLSPHINXOPTS) "$(BUILDDIR)/$@"
+
diff --git a/doc/baseconf.py b/doc/baseconf.py
new file mode 100644
index 00000000000..1ed19cc0579
--- /dev/null
+++ b/doc/baseconf.py
@@ -0,0 +1,103 @@
+# Configuration file for the Sphinx documentation builder.
+#
+# This file only contains a selection of the most common options. For a full
+# list see the documentation:
+# https://www.sphinx-doc.org/en/master/usage/configuration.html
+
+# -- Path setup --------------------------------------------------------------
+
+# If extensions (or modules to document with autodoc) are in another directory,
+# add these directories to sys.path here. If the directory is relative to the
+# documentation root, use os.path.abspath to make it absolute, like shown here.
+#
+import os
+# import sys
+# sys.path.insert(0, os.path.abspath('.'))
+
+
+# -- Project information -----------------------------------------------------
+
+# The full version, including alpha/beta/rc tags
+
+# FIXME
+folder = os.path.dirname(os.path.realpath(__file__))
+gcc_srcdir = os.path.join(folder, './objdir')
+
+def __read_file(name):
+ path = os.path.join(gcc_srcdir, name)
+ if os.path.exists(path):
+ return open(path).read().strip()
+ else:
+ return ''
+
+gcc_BASEVER = __read_file('BASE-VER')
+gcc_DEVPHASE = __read_file('DEV-PHASE')
+gcc_DATESTAMP = __read_file('DATESTAMP')
+gcc_REVISION = __read_file('REVISION')
+
+VERSION_PACKAGE = os.getenv('VERSION_PACKAGE', '(GCC)')
+BUGURL = os.getenv('BUGURL', 'https://gcc.gnu.org/bugs/')
+
+# The short X.Y version.
+version = gcc_BASEVER
+
+# The full version, including alpha/beta/rc tags.
+release = ('%s (%s %s%s)'
+ % (gcc_BASEVER, gcc_DEVPHASE, gcc_DATESTAMP,
+ (' %s' % gcc_REVISION) if gcc_REVISION else ''))
+
+rst_epilog = '''
+.. |gcc_version| replace:: %s
+.. |package_version| replace:: %s
+.. |bugurl| replace:: %s
+''' % (gcc_BASEVER, VERSION_PACKAGE, BUGURL)
+
+# -- General configuration ---------------------------------------------------
+
+# Add any Sphinx extension module names here, as strings. They can be
+# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
+# ones.
+extensions = [
+]
+
+# Add any paths that contain templates here, relative to this directory.
+templates_path = ['_templates']
+
+# List of patterns, relative to source directory, that match files and
+# directories to ignore when looking for source files.
+# This pattern also affects html_static_path and html_extra_path.
+exclude_patterns = ['_build']
+
+# For legacy Sphinx versions (< 2.0)
+master_doc = 'index'
+
+# -- Options for HTML output -------------------------------------------------
+
+# The theme to use for HTML and HTML Help pages. See the documentation for
+# a list of builtin themes.
+#
+html_theme = 'sphinx_rtd_theme'
+
+# Theme options are theme-specific and customize the look and feel of a theme
+# further. For a list of options available for each theme, see the
+# documentation.
+html_theme_options = {
+ 'prev_next_buttons_location': 'both',
+ 'navigation_with_keys': True
+}
+
+# By default, do not generate any manual pages
+man_pages = []
+
+# FIXME: handle WARNINGs: unknown option issues and cross refs
+suppress_warnings = [
+ 'ref.option',
+ 'ref.ref'
+]
+
+# RTD template requires at least Sphinx 1.6
+# sphinx-build -j auto is supported since 1.7
+needs_sphinx = '1.7'
+
+# Use xelatex by default
+latex_engine = 'xelatex'
diff --git a/doc/bsd.rst b/doc/bsd.rst
new file mode 100644
index 00000000000..5624c3701b4
--- /dev/null
+++ b/doc/bsd.rst
@@ -0,0 +1,39 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+BSD
+===
+
+Copyright (C) 1990 Regents of the University of California.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+#. Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+
+#. Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+
+#. [rescinded 22 July 1999]
+
+#. Neither the name of the University nor the names of its contributors
+ may be used to endorse or promote products derived from this software
+ without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS 'AS IS' AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGE.
\ No newline at end of file
diff --git a/doc/contrib.rst b/doc/contrib.rst
new file mode 100644
index 00000000000..7e877dc94f8
--- /dev/null
+++ b/doc/contrib.rst
@@ -0,0 +1,1277 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _contributors:
+
+Contributors to GCC
+===================
+
+.. index:: contributors
+
+The GCC project would like to thank its many contributors. Without them the
+project would not have been nearly as successful as it has been. Any omissions
+in this list are accidental. Feel free to contact
+law@redhat.com or gerald@pfeifer.com if you have been left
+out or some of your contributions are not listed. Please keep this list in
+alphabetical order.
+
+* Analog Devices helped implement the support for complex data types
+ and iterators.
+
+* John David Anglin for threading-related fixes and improvements to
+ libstdc++-v3, and the HP-UX port.
+
+* James van Artsdalen wrote the code that makes efficient use of
+ the Intel 80387 register stack.
+
+* Abramo and Roberto Bagnara for the SysV68 Motorola 3300 Delta Series
+ port.
+
+* Alasdair Baird for various bug fixes.
+
+* Giovanni Bajo for analyzing lots of complicated C++ problem reports.
+
+* Peter Barada for his work to improve code generation for new
+ ColdFire cores.
+
+* Gerald Baumgartner added the signature extension to the C++ front end.
+
+* Godmar Back for his Java improvements and encouragement.
+
+* Scott Bambrough for help porting the Java compiler.
+
+* Wolfgang Bangerth for processing tons of bug reports.
+
+* Jon Beniston for his Microsoft Windows port of Java and port to Lattice Mico32.
+
+* Daniel Berlin for better DWARF 2 support, faster/better optimizations,
+ improved alias analysis, plus migrating GCC to Bugzilla.
+
+* Geoff Berry for his Java object serialization work and various patches.
+
+* David Binderman tests weekly snapshots of GCC trunk against Fedora Rawhide
+ for several architectures.
+
+* Laurynas Biveinis for memory management work and DJGPP port fixes.
+
+* Uros Bizjak for the implementation of x87 math built-in functions and
+ for various middle end and i386 back end improvements and bug fixes.
+
+* Eric Blake for helping to make GCJ and libgcj conform to the
+ specifications.
+
+* Janne Blomqvist for contributions to GNU Fortran.
+
+* Hans-J. Boehm for his garbage collector, IA-64 libffi port, and other
+ Java work.
+
+* Segher Boessenkool for helping maintain the PowerPC port and the
+ instruction combiner plus various contributions to the middle end.
+
+* Neil Booth for work on cpplib, lang hooks, debug hooks and other
+ miscellaneous clean-ups.
+
+* Steven Bosscher for integrating the GNU Fortran front end into GCC and for
+ contributing to the tree-ssa branch.
+
+* Eric Botcazou for fixing middle- and backend bugs left and right.
+
+* Per Bothner for his direction via the steering committee and various
+ improvements to the infrastructure for supporting new languages. Chill
+ front end implementation. Initial implementations of
+ cpplib, fix-header, config.guess, libio, and past C++ library (libg++)
+ maintainer. Dreaming up, designing and implementing much of GCJ.
+
+* Devon Bowen helped port GCC to the Tahoe.
+
+* Don Bowman for mips-vxworks contributions.
+
+* James Bowman for the FT32 port.
+
+* Dave Brolley for work on cpplib and Chill.
+
+* Paul Brook for work on the ARM architecture and maintaining GNU Fortran.
+
+* Robert Brown implemented the support for Encore 32000 systems.
+
+* Christian Bruel for improvements to local store elimination.
+
+* Herman A.J. ten Brugge for various fixes.
+
+* Joerg Brunsmann for Java compiler hacking and help with the GCJ FAQ.
+
+* Joe Buck for his direction via the steering committee from its creation
+ to 2013.
+
+* Iain Buclaw for the D frontend.
+
+* Craig Burley for leadership of the G77 Fortran effort.
+
+* Tobias Burnus for contributions to GNU Fortran.
+
+* Stephan Buys for contributing Doxygen notes for libstdc++.
+
+* Paolo Carlini for libstdc++ work: lots of efficiency improvements to
+ the C++ strings, streambufs and formatted I/O, hard detective work on
+ the frustrating localization issues, and keeping up with the problem reports.
+
+* John Carr for his alias work, SPARC hacking, infrastructure improvements,
+ previous contributions to the steering committee, loop optimizations, etc.
+
+* Stephane Carrez for 68HC11 and 68HC12 ports.
+
+* Steve Chamberlain for support for the Renesas SH and H8 processors
+ and the PicoJava processor, and for GCJ config fixes.
+
+* Glenn Chambers for help with the GCJ FAQ.
+
+* John-Marc Chandonia for various libgcj patches.
+
+* Denis Chertykov for contributing and maintaining the AVR port, the first GCC port
+ for an 8-bit architecture.
+
+* Kito Cheng for his work on the RISC-V port, including bringing up the test
+ suite and maintenance.
+
+* Scott Christley for his Objective-C contributions.
+
+* Eric Christopher for his Java porting help and clean-ups.
+
+* Branko Cibej for more warning contributions.
+
+* The `GNU Classpath project <http://www.gnu.org/software/classpath/>`_
+ for all of their merged runtime code.
+
+* Nick Clifton for arm, mcore, fr30, v850, m32r, msp430 rx work,
+ :option:`--help`, and other random hacking.
+
+* Michael Cook for libstdc++ cleanup patches to reduce warnings.
+
+* R. Kelley Cook for making GCC buildable from a read-only directory as
+ well as other miscellaneous build process and documentation clean-ups.
+
+* Ralf Corsepius for SH testing and minor bug fixing.
+
+* François-Xavier Coudert for contributions to GNU Fortran.
+
+* Stan Cox for care and feeding of the x86 port and lots of behind
+ the scenes hacking.
+
+* Alex Crain provided changes for the 3b1.
+
+* Ian Dall for major improvements to the NS32k port.
+
+* Paul Dale for his work to add uClinux platform support to the
+ m68k backend.
+
+* Palmer Dabbelt for his work maintaining the RISC-V port.
+
+* Dario Dariol contributed the four varieties of sample programs
+ that print a copy of their source.
+
+* Russell Davidson for fstream and stringstream fixes in libstdc++.
+
+* Bud Davis for work on the G77 and GNU Fortran compilers.
+
+* Mo DeJong for GCJ and libgcj bug fixes.
+
+* Jerry DeLisle for contributions to GNU Fortran.
+
+* DJ Delorie for the DJGPP port, build and libiberty maintenance,
+ various bug fixes, and the M32C, MeP, MSP430, and RL78 ports.
+
+* Arnaud Desitter for helping to debug GNU Fortran.
+
+* Gabriel Dos Reis for contributions to G++, contributions and
+ maintenance of GCC diagnostics infrastructure, libstdc++-v3,
+ including ``valarray<>``, ``complex<>``, maintaining the numerics library
+ (including that pesky ``<limits>`` :-) and keeping up-to-date anything
+ to do with numbers.
+
+* Ulrich Drepper for his work on glibc, testing of GCC using glibc, ISO C99
+ support, CFG dumping support, etc., plus support of the C++ runtime
+ libraries including for all kinds of C interface issues, contributing and
+ maintaining ``complex<>``, sanity checking and disbursement, configuration
+ architecture, libio maintenance, and early math work.
+
+* François Dumont for his work on libstdc++-v3, especially maintaining and
+ improving ``debug-mode`` and associative and unordered containers.
+
+* Zdenek Dvorak for a new loop unroller and various fixes.
+
+* Michael Eager for his work on the Xilinx MicroBlaze port.
+
+* Richard Earnshaw for his ongoing work with the ARM.
+
+* David Edelsohn for his direction via the steering committee, ongoing work
+ with the RS6000/PowerPC port, help cleaning up Haifa loop changes,
+ doing the entire AIX port of libstdc++ with his bare hands, and for
+ ensuring GCC properly keeps working on AIX.
+
+* Kevin Ediger for the floating point formatting of num_put::do_put in
+ libstdc++.
+
+* Phil Edwards for libstdc++ work including configuration hackery,
+ documentation maintainer, chief breaker of the web pages, the occasional
+ iostream bug fix, and work on shared library symbol versioning.
+
+* Paul Eggert for random hacking all over GCC.
+
+* Mark Elbrecht for various DJGPP improvements, and for libstdc++
+ configuration support for locales and fstream-related fixes.
+
+* Vadim Egorov for libstdc++ fixes in strings, streambufs, and iostreams.
+
+* Christian Ehrhardt for dealing with bug reports.
+
+* Ben Elliston for his work to move the Objective-C runtime into its
+ own subdirectory and for his work on autoconf.
+
+* Revital Eres for work on the PowerPC 750CL port.
+
+* Marc Espie for OpenBSD support.
+
+* Doug Evans for much of the global optimization framework, arc, m32r,
+ and SPARC work.
+
+* Christopher Faylor for his work on the Cygwin port and for caring and
+ feeding the gcc.gnu.org box and saving its users tons of spam.
+
+* Fred Fish for BeOS support and Ada fixes.
+
+* Ivan Fontes Garcia for the Portuguese translation of the GCJ FAQ.
+
+* Peter Gerwinski for various bug fixes and the Pascal front end.
+
+* Kaveh R. Ghazi for his direction via the steering committee, amazing
+ work to make :samp:`-W -Wall -W* -Werror` useful, and
+ testing GCC on a plethora of platforms. Kaveh extends his gratitude to
+ the CAIP Center at Rutgers University for providing him with computing
+ resources to work on Free Software from the late 1980s to 2010.
+
+* John Gilmore for a donation to the FSF earmarked improving GNU Java.
+
+* Judy Goldberg for c++ contributions.
+
+* Torbjorn Granlund for various fixes and the c-torture testsuite,
+ multiply- and divide-by-constant optimization, improved long long
+ support, improved leaf function register allocation, and his direction
+ via the steering committee.
+
+* Jonny Grant for improvements to ``collect2's`` :option:`--help` documentation.
+
+* Anthony Green for his :option:`-Os` contributions, the moxie port, and
+ Java front end work.
+
+* Stu Grossman for gdb hacking, allowing GCJ developers to debug Java code.
+
+* Michael K. Gschwind contributed the port to the PDP-11.
+
+* Richard Biener for his ongoing middle-end contributions and bug fixes
+ and for release management.
+
+* Ron Guilmette implemented the :command:`protoize` and :command:`unprotoize`
+ tools, the support for DWARF 1 symbolic debugging information, and much of
+ the support for System V Release 4. He has also worked heavily on the
+ Intel 386 and 860 support.
+
+* Sumanth Gundapaneni for contributing the CR16 port.
+
+* Mostafa Hagog for Swing Modulo Scheduling (SMS) and post reload GCSE.
+
+* Bruno Haible for improvements in the runtime overhead for EH, new
+ warnings and assorted bug fixes.
+
+* Andrew Haley for his amazing Java compiler and library efforts.
+
+* Chris Hanson assisted in making GCC work on HP-UX for the 9000 series 300.
+
+* Michael Hayes for various thankless work he's done trying to get
+ the c30/c40 ports functional. Lots of loop and unroll improvements and
+ fixes.
+
+* Dara Hazeghi for wading through myriads of target-specific bug reports.
+
+* Kate Hedstrom for staking the G77 folks with an initial testsuite.
+
+* Richard Henderson for his ongoing SPARC, alpha, ia32, and ia64 work, loop
+ opts, and generally fixing lots of old problems we've ignored for
+ years, flow rewrite and lots of further stuff, including reviewing
+ tons of patches.
+
+* Aldy Hernandez for working on the PowerPC port, SIMD support, and
+ various fixes.
+
+* Nobuyuki Hikichi of Software Research Associates, Tokyo, contributed
+ the support for the Sony NEWS machine.
+
+* Kazu Hirata for caring and feeding the Renesas H8/300 port and various fixes.
+
+* Katherine Holcomb for work on GNU Fortran.
+
+* Manfred Hollstein for his ongoing work to keep the m88k alive, lots
+ of testing and bug fixing, particularly of GCC configury code.
+
+* Steve Holmgren for MachTen patches.
+
+* Mat Hostetter for work on the TILE-Gx and TILEPro ports.
+
+* Jan Hubicka for his x86 port improvements.
+
+* Falk Hueffner for working on C and optimization bug reports.
+
+* Bernardo Innocenti for his m68k work, including merging of
+ ColdFire improvements and uClinux support.
+
+* Christian Iseli for various bug fixes.
+
+* Kamil Iskra for general m68k hacking.
+
+* Lee Iverson for random fixes and MIPS testing.
+
+* Balaji V. Iyer for Cilk+ development and merging.
+
+* Andreas Jaeger for testing and benchmarking of GCC and various bug fixes.
+
+* Martin Jambor for his work on inter-procedural optimizations, the
+ switch conversion pass, and scalar replacement of aggregates.
+
+* Jakub Jelinek for his SPARC work and sibling call optimizations as well
+ as lots of bug fixes and test cases, and for improving the Java build
+ system.
+
+* Janis Johnson for ia64 testing and fixes, her quality improvement
+ sidetracks, and web page maintenance.
+
+* Kean Johnston for SCO OpenServer support and various fixes.
+
+* Tim Josling for the sample language treelang based originally on Richard
+ Kenner's 'toy' language.
+
+* Nicolai Josuttis for additional libstdc++ documentation.
+
+* Klaus Kaempf for his ongoing work to make alpha-vms a viable target.
+
+* Steven G. Kargl for work on GNU Fortran.
+
+* David Kashtan of SRI adapted GCC to VMS.
+
+* Ryszard Kabatek for many, many libstdc++ bug fixes and optimizations of
+ strings, especially member functions, and for auto_ptr fixes.
+
+* Geoffrey Keating for his ongoing work to make the PPC work for GNU/Linux
+ and his automatic regression tester.
+
+* Brendan Kehoe for his ongoing work with G++ and for a lot of early work
+ in just about every part of libstdc++.
+
+* Oliver M. Kellogg of Deutsche Aerospace contributed the port to the
+ MIL-STD-1750A.
+
+* Richard Kenner of the New York University Ultracomputer Research
+ Laboratory wrote the machine descriptions for the AMD 29000, the DEC
+ Alpha, the IBM RT PC, and the IBM RS/6000 as well as the support for
+ instruction attributes. He also made changes to better support RISC
+ processors including changes to common subexpression elimination,
+ strength reduction, function calling sequence handling, and condition
+ code support, in addition to generalizing the code for frame pointer
+ elimination and delay slot scheduling. Richard Kenner was also the
+ head maintainer of GCC for several years.
+
+* Mumit Khan for various contributions to the Cygwin and Mingw32 ports and
+ maintaining binary releases for Microsoft Windows hosts, and for massive libstdc++
+ porting work to Cygwin/Mingw32.
+
+* Robin Kirkham for cpu32 support.
+
+* Mark Klein for PA improvements.
+
+* Thomas Koenig for various bug fixes.
+
+* Bruce Korb for the new and improved fixincludes code.
+
+* Benjamin Kosnik for his G++ work and for leading the libstdc++-v3 effort.
+
+* Maxim Kuvyrkov for contributions to the instruction scheduler, the Android
+ and m68k/Coldfire ports, and optimizations.
+
+* Charles LaBrec contributed the support for the Integrated Solutions
+ 68020 system.
+
+* Asher Langton and Mike Kumbera for contributing Cray pointer support
+ to GNU Fortran, and for other GNU Fortran improvements.
+
+* Jeff Law for his direction via the steering committee, coordinating the
+ entire egcs project and GCC 2.95, rolling out snapshots and releases,
+ handling merges from GCC2, reviewing tons of patches that might have
+ fallen through the cracks else, and random but extensive hacking.
+
+* Walter Lee for work on the TILE-Gx and TILEPro ports.
+
+* Marc Lehmann for his direction via the steering committee and helping
+ with analysis and improvements of x86 performance.
+
+* Victor Leikehman for work on GNU Fortran.
+
+* Ted Lemon wrote parts of the RTL reader and printer.
+
+* Kriang Lerdsuwanakij for C++ improvements including template as template
+ parameter support, and many C++ fixes.
+
+* Warren Levy for tremendous work on libgcj (Java Runtime Library) and
+ random work on the Java front end.
+
+* Alain Lichnewsky ported GCC to the MIPS CPU.
+
+* Oskar Liljeblad for hacking on AWT and his many Java bug reports and
+ patches.
+
+* Robert Lipe for OpenServer support, new testsuites, testing, etc.
+
+* Chen Liqin for various S+core related fixes/improvement, and for
+ maintaining the S+core port.
+
+* Martin Liska for his work on identical code folding, the sanitizers,
+ HSA, general bug fixing and for running automated regression testing of GCC
+ and reporting numerous bugs.
+
+* Weiwen Liu for testing and various bug fixes.
+
+* Manuel López-Ibáñez for improving :option:`-Wconversion` and
+ many other diagnostics fixes and improvements.
+
+* Dave Love for his ongoing work with the Fortran front end and
+ runtime libraries.
+
+* Martin von Löwis for internal consistency checking infrastructure,
+ various C++ improvements including namespace support, and tons of
+ assistance with libstdc++/compiler merges.
+
+* H.J. Lu for his previous contributions to the steering committee, many x86
+ bug reports, prototype patches, and keeping the GNU/Linux ports working.
+
+* Greg McGary for random fixes and (someday) bounded pointers.
+
+* Andrew MacLeod for his ongoing work in building a real EH system,
+ various code generation improvements, work on the global optimizer, etc.
+
+* Vladimir Makarov for hacking some ugly i960 problems, PowerPC hacking
+ improvements to compile-time performance, overall knowledge and
+ direction in the area of instruction scheduling, design and
+ implementation of the automaton based instruction scheduler and
+ design and implementation of the integrated and local register allocators.
+
+* David Malcolm for his work on improving GCC diagnostics, JIT, self-tests
+ and unit testing.
+
+* Bob Manson for his behind the scenes work on dejagnu.
+
+* John Marino for contributing the DragonFly BSD port.
+
+* Philip Martin for lots of libstdc++ string and vector iterator fixes and
+ improvements, and string clean up and testsuites.
+
+* Michael Matz for his work on dominance tree discovery, the x86-64 port,
+ link-time optimization framework and general optimization improvements.
+
+* All of the Mauve project contributors for Java test code.
+
+* Bryce McKinlay for numerous GCJ and libgcj fixes and improvements.
+
+* Adam Megacz for his work on the Microsoft Windows port of GCJ.
+
+* Michael Meissner for LRS framework, ia32, m32r, v850, m88k, MIPS,
+ powerpc, haifa, ECOFF debug support, and other assorted hacking.
+
+* Jason Merrill for his direction via the steering committee and leading
+ the G++ effort.
+
+* Martin Michlmayr for testing GCC on several architectures using the
+ entire Debian archive.
+
+* David Miller for his direction via the steering committee, lots of
+ SPARC work, improvements in jump.c and interfacing with the Linux kernel
+ developers.
+
+* Gary Miller ported GCC to Charles River Data Systems machines.
+
+* Alfred Minarik for libstdc++ string and ios bug fixes, and turning the
+ entire libstdc++ testsuite namespace-compatible.
+
+* Mark Mitchell for his direction via the steering committee, mountains of
+ C++ work, load/store hoisting out of loops, alias analysis improvements,
+ ISO C ``restrict`` support, and serving as release manager from 2000
+ to 2011.
+
+* Alan Modra for various GNU/Linux bits and testing.
+
+* Toon Moene for his direction via the steering committee, Fortran
+ maintenance, and his ongoing work to make us make Fortran run fast.
+
+* Jason Molenda for major help in the care and feeding of all the services
+ on the gcc.gnu.org (formerly egcs.cygnus.com) machine---mail, web
+ services, ftp services, etc etc. Doing all this work on scrap paper and
+ the backs of envelopes would have been... difficult.
+
+* Catherine Moore for fixing various ugly problems we have sent her
+ way, including the haifa bug which was killing the Alpha & PowerPC
+ Linux kernels.
+
+* Mike Moreton for his various Java patches.
+
+* David Mosberger-Tang for various Alpha improvements, and for the initial
+ IA-64 port.
+
+* Stephen Moshier contributed the floating point emulator that assists in
+ cross-compilation and permits support for floating point numbers wider
+ than 64 bits and for ISO C99 support.
+
+* Bill Moyer for his behind the scenes work on various issues.
+
+* Philippe De Muyter for his work on the m68k port.
+
+* Joseph S. Myers for his work on the PDP-11 port, format checking and ISO
+ C99 support, and continuous emphasis on (and contributions to) documentation.
+
+* Nathan Myers for his work on libstdc++-v3: architecture and authorship
+ through the first three snapshots, including implementation of locale
+ infrastructure, string, shadow C headers, and the initial project
+ documentation (DESIGN, CHECKLIST, and so forth). Later, more work on
+ MT-safe string and shadow headers.
+
+* Felix Natter for documentation on porting libstdc++.
+
+* Nathanael Nerode for cleaning up the configuration/build process.
+
+* NeXT, Inc. donated the front end that supports the Objective-C
+ language.
+
+* Hans-Peter Nilsson for the CRIS and MMIX ports, improvements to the search
+ engine setup, various documentation fixes and other small fixes.
+
+* Geoff Noer for his work on getting cygwin native builds working.
+
+* Vegard Nossum for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Diego Novillo for his work on Tree SSA, OpenMP, SPEC performance
+ tracking web pages, GIMPLE tuples, and assorted fixes.
+
+* David O'Brien for the FreeBSD/alpha, FreeBSD/AMD x86-64, FreeBSD/ARM,
+ FreeBSD/PowerPC, and FreeBSD/SPARC64 ports and related infrastructure
+ improvements.
+
+* Alexandre Oliva for various build infrastructure improvements, scripts and
+ amazing testing work, including keeping libtool issues sane and happy.
+
+* Stefan Olsson for work on mt_alloc.
+
+* Melissa O'Neill for various NeXT fixes.
+
+* Rainer Orth for random MIPS work, including improvements to GCC's o32
+ ABI support, improvements to dejagnu's MIPS support, Java configuration
+ clean-ups and porting work, and maintaining the IRIX, Solaris 2, and
+ Tru64 UNIX ports.
+
+* Steven Pemberton for his contribution of :samp:`enquire` which allowed GCC to
+ determine various properties of the floating point unit and generate
+ :samp:`float.h` in older versions of GCC.
+
+* Hartmut Penner for work on the s390 port.
+
+* Paul Petersen wrote the machine description for the Alliant FX/8.
+
+* Alexandre Petit-Bianco for implementing much of the Java compiler and
+ continued Java maintainership.
+
+* Matthias Pfaller for major improvements to the NS32k port.
+
+* Gerald Pfeifer for his direction via the steering committee, pointing
+ out lots of problems we need to solve, maintenance of the web pages, and
+ taking care of documentation maintenance in general.
+
+* Marek Polacek for his work on the C front end, the sanitizers and general
+ bug fixing.
+
+* Andrew Pinski for processing bug reports by the dozen.
+
+* Ovidiu Predescu for his work on the Objective-C front end and runtime
+ libraries.
+
+* Jerry Quinn for major performance improvements in C++ formatted I/O.
+
+* Ken Raeburn for various improvements to checker, MIPS ports and various
+ cleanups in the compiler.
+
+* Rolf W. Rasmussen for hacking on AWT.
+
+* David Reese of Sun Microsystems contributed to the Solaris on PowerPC
+ port.
+
+* John Regehr for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Volker Reichelt for running automated regression testing of GCC and reporting
+ numerous bugs and for keeping up with the problem reports.
+
+* Joern Rennecke for maintaining the sh port, loop, regmove & reload
+ hacking and developing and maintaining the Epiphany port.
+
+* Loren J. Rittle for improvements to libstdc++-v3 including the FreeBSD
+ port, threading fixes, thread-related configury changes, critical
+ threading documentation, and solutions to really tricky I/O problems,
+ as well as keeping GCC properly working on FreeBSD and continuous testing.
+
+* Craig Rodrigues for processing tons of bug reports.
+
+* Ola Rönnerup for work on mt_alloc.
+
+* Gavin Romig-Koch for lots of behind the scenes MIPS work.
+
+* David Ronis inspired and encouraged Craig to rewrite the G77
+ documentation in texinfo format by contributing a first pass at a
+ translation of the old :samp:`g77-0.5.16/f/DOC` file.
+
+* Ken Rose for fixes to GCC's delay slot filling code.
+
+* Ira Rosen for her contributions to the auto-vectorizer.
+
+* Paul Rubin wrote most of the preprocessor.
+
+* Pétur Runólfsson for major performance improvements in C++ formatted I/O and
+ large file support in C++ filebuf.
+
+* Chip Salzenberg for libstdc++ patches and improvements to locales, traits,
+ Makefiles, libio, libtool hackery, and 'long long' support.
+
+* Juha Sarlin for improvements to the H8 code generator.
+
+* Greg Satz assisted in making GCC work on HP-UX for the 9000 series 300.
+
+* Roger Sayle for improvements to constant folding and GCC's RTL optimizers
+ as well as for fixing numerous bugs.
+
+* Bradley Schatz for his work on the GCJ FAQ.
+
+* Peter Schauer wrote the code to allow debugging to work on the Alpha.
+
+* William Schelter did most of the work on the Intel 80386 support.
+
+* Tobias Schlüter for work on GNU Fortran.
+
+* Bernd Schmidt for various code generation improvements and major
+ work in the reload pass, serving as release manager for
+ GCC 2.95.3, and work on the Blackfin and C6X ports.
+
+* Peter Schmid for constant testing of libstdc++---especially application
+ testing, going above and beyond what was requested for the release
+ criteria---and libstdc++ header file tweaks.
+
+* Jason Schroeder for jcf-dump patches.
+
+* Andreas Schwab for his work on the m68k port.
+
+* Lars Segerlund for work on GNU Fortran.
+
+* Dodji Seketeli for numerous C++ bug fixes and debug info improvements.
+
+* Tim Shen for major work on ``<regex>``.
+
+* Joel Sherrill for his direction via the steering committee, RTEMS
+ contributions and RTEMS testing.
+
+* Nathan Sidwell for many C++ fixes/improvements.
+
+* Jeffrey Siegal for helping RMS with the original design of GCC, some
+ code which handles the parse tree and RTL data structures, constant
+ folding and help with the original VAX & m68k ports.
+
+* Kenny Simpson for prompting libstdc++ fixes due to defect reports from
+ the LWG (thereby keeping GCC in line with updates from the ISO).
+
+* Franz Sirl for his ongoing work with making the PPC port stable
+ for GNU/Linux.
+
+* Andrey Slepuhin for assorted AIX hacking.
+
+* Trevor Smigiel for contributing the SPU port.
+
+* Christopher Smith did the port for Convex machines.
+
+* Danny Smith for his major efforts on the Mingw (and Cygwin) ports.
+ Retired from GCC maintainership August 2010, having mentored two
+ new maintainers into the role.
+
+* Randy Smith finished the Sun FPA support.
+
+* Ed Smith-Rowland for his continuous work on libstdc++-v3, special functions,
+ ``<random>``, and various improvements to C++11 features.
+
+* Scott Snyder for queue, iterator, istream, and string fixes and libstdc++
+ testsuite entries. Also for providing the patch to G77 to add
+ rudimentary support for ``INTEGER*1``, ``INTEGER*2``, and
+ ``LOGICAL*1``.
+
+* Zdenek Sojka for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Arseny Solokha for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Jayant Sonar for contributing the CR16 port.
+
+* Brad Spencer for contributions to the GLIBCPP_FORCE_NEW technique.
+
+* Richard Stallman, for writing the original GCC and launching the GNU project.
+
+* Jan Stein of the Chalmers Computer Society provided support for
+ Genix, as well as part of the 32000 machine description.
+
+* Gerhard Steinmetz for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Nigel Stephens for various mips16 related fixes/improvements.
+
+* Jonathan Stone wrote the machine description for the Pyramid computer.
+
+* Graham Stott for various infrastructure improvements.
+
+* John Stracke for his Java HTTP protocol fixes.
+
+* Mike Stump for his Elxsi port, G++ contributions over the years and more
+ recently his vxworks contributions
+
+* Jeff Sturm for Java porting help, bug fixes, and encouragement.
+
+* Zhendong Su for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Chengnian Sun for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Shigeya Suzuki for this fixes for the bsdi platforms.
+
+* Ian Lance Taylor for the Go frontend, the initial mips16 and mips64
+ support, general configury hacking, fixincludes, etc.
+
+* Holger Teutsch provided the support for the Clipper CPU.
+
+* Gary Thomas for his ongoing work to make the PPC work for GNU/Linux.
+
+* Paul Thomas for contributions to GNU Fortran.
+
+* Philipp Thomas for random bug fixes throughout the compiler
+
+* Jason Thorpe for thread support in libstdc++ on NetBSD.
+
+* Kresten Krab Thorup wrote the run time support for the Objective-C
+ language and the fantastic Java bytecode interpreter.
+
+* Michael Tiemann for random bug fixes, the first instruction scheduler,
+ initial C++ support, function integration, NS32k, SPARC and M88k
+ machine description work, delay slot scheduling.
+
+* Andreas Tobler for his work porting libgcj to Darwin.
+
+* Teemu Torma for thread safe exception handling support.
+
+* Leonard Tower wrote parts of the parser, RTL generator, and RTL
+ definitions, and of the VAX machine description.
+
+* Daniel Towner and Hariharan Sandanagobalane contributed and
+ maintain the picoChip port.
+
+* Tom Tromey for internationalization support and for his many Java
+ contributions and libgcj maintainership.
+
+* Lassi Tuura for improvements to config.guess to determine HP processor
+ types.
+
+* Petter Urkedal for libstdc++ CXXFLAGS, math, and algorithms fixes.
+
+* Andy Vaught for the design and initial implementation of the GNU Fortran
+ front end.
+
+* Brent Verner for work with the libstdc++ cshadow files and their
+ associated configure steps.
+
+* Todd Vierling for contributions for NetBSD ports.
+
+* Andrew Waterman for contributing the RISC-V port, as well as maintaining it.
+
+* Jonathan Wakely for contributing libstdc++ Doxygen notes and XHTML
+ guidance and maintaining libstdc++.
+
+* Dean Wakerley for converting the install documentation from HTML to texinfo
+ in time for GCC 3.0.
+
+* Krister Walfridsson for random bug fixes.
+
+* Feng Wang for contributions to GNU Fortran.
+
+* Stephen M. Webb for time and effort on making libstdc++ shadow files
+ work with the tricky Solaris 8+ headers, and for pushing the build-time
+ header tree. Also, for starting and driving the ``<regex>`` effort.
+
+* John Wehle for various improvements for the x86 code generator,
+ related infrastructure improvements to help x86 code generation,
+ value range propagation and other work, WE32k port.
+
+* Ulrich Weigand for work on the s390 port.
+
+* Janus Weil for contributions to GNU Fortran.
+
+* Zack Weinberg for major work on cpplib and various other bug fixes.
+
+* Matt Welsh for help with Linux Threads support in GCJ.
+
+* Urban Widmark for help fixing java.io.
+
+* Mark Wielaard for new Java library code and his work integrating with
+ Classpath.
+
+* Dale Wiles helped port GCC to the Tahoe.
+
+* Bob Wilson from Tensilica, Inc. for the Xtensa port.
+
+* Jim Wilson for his direction via the steering committee, tackling hard
+ problems in various places that nobody else wanted to work on, strength
+ reduction and other loop optimizations.
+
+* Paul Woegerer and Tal Agmon for the CRX port.
+
+* Carlo Wood for various fixes.
+
+* Tom Wood for work on the m88k port.
+
+* Chung-Ju Wu for his work on the Andes NDS32 port.
+
+* Canqun Yang for work on GNU Fortran.
+
+* Masanobu Yuhara of Fujitsu Laboratories implemented the machine
+ description for the Tron architecture (specifically, the Gmicro).
+
+* Kevin Zachmann helped port GCC to the Tahoe.
+
+* Ayal Zaks for Swing Modulo Scheduling (SMS).
+
+* Qirun Zhang for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Xiaoqiang Zhang for work on GNU Fortran.
+
+* Gilles Zunino for help porting Java to Irix.
+
+The following people are recognized for their contributions to GNAT,
+the Ada front end of GCC:
+
+* Bernard Banner
+
+* Romain Berrendonner
+
+* Geert Bosch
+
+* Emmanuel Briot
+
+* Joel Brobecker
+
+* Ben Brosgol
+
+* Vincent Celier
+
+* Arnaud Charlet
+
+* Chien Chieng
+
+* Cyrille Comar
+
+* Cyrille Crozes
+
+* Robert Dewar
+
+* Gary Dismukes
+
+* Robert Duff
+
+* Ed Falis
+
+* Ramon Fernandez
+
+* Sam Figueroa
+
+* Vasiliy Fofanov
+
+* Michael Friess
+
+* Franco Gasperoni
+
+* Ted Giering
+
+* Matthew Gingell
+
+* Laurent Guerby
+
+* Jerome Guitton
+
+* Olivier Hainque
+
+* Jerome Hugues
+
+* Hristian Kirtchev
+
+* Jerome Lambourg
+
+* Bruno Leclerc
+
+* Albert Lee
+
+* Sean McNeil
+
+* Javier Miranda
+
+* Laurent Nana
+
+* Pascal Obry
+
+* Dong-Ik Oh
+
+* Laurent Pautet
+
+* Brett Porter
+
+* Thomas Quinot
+
+* Nicolas Roche
+
+* Pat Rogers
+
+* Jose Ruiz
+
+* Douglas Rupp
+
+* Sergey Rybin
+
+* Gail Schenker
+
+* Ed Schonberg
+
+* Nicolas Setton
+
+* Samuel Tardieu
+
+The following people are recognized for their contributions of new
+features, bug reports, testing and integration of classpath/libgcj for
+GCC version 4.1:
+
+* Lillian Angel for ``JTree`` implementation and lots Free Swing
+ additions and bug fixes.
+
+* Wolfgang Baer for ``GapContent`` bug fixes.
+
+* Anthony Balkissoon for ``JList``, Free Swing 1.5 updates and mouse event
+ fixes, lots of Free Swing work including ``JTable`` editing.
+
+* Stuart Ballard for RMI constant fixes.
+
+* Goffredo Baroncelli for ``HTTPURLConnection`` fixes.
+
+* Gary Benson for ``MessageFormat`` fixes.
+
+* Daniel Bonniot for ``Serialization`` fixes.
+
+* Chris Burdess for lots of gnu.xml and http protocol fixes, ``StAX``
+ and ``DOM xml:id`` support.
+
+* Ka-Hing Cheung for ``TreePath`` and ``TreeSelection`` fixes.
+
+* Archie Cobbs for build fixes, VM interface updates,
+ ``URLClassLoader`` updates.
+
+* Kelley Cook for build fixes.
+
+* Martin Cordova for Suggestions for better ``SocketTimeoutException``.
+
+* David Daney for ``BitSet`` bug fixes, ``HttpURLConnection``
+ rewrite and improvements.
+
+* Thomas Fitzsimmons for lots of upgrades to the gtk+ AWT and Cairo 2D
+ support. Lots of imageio framework additions, lots of AWT and Free
+ Swing bug fixes.
+
+* Jeroen Frijters for ``ClassLoader`` and nio cleanups, serialization fixes,
+ better ``Proxy`` support, bug fixes and IKVM integration.
+
+* Santiago Gala for ``AccessControlContext`` fixes.
+
+* Nicolas Geoffray for ``VMClassLoader`` and ``AccessController``
+ improvements.
+
+* David Gilbert for ``basic`` and ``metal`` icon and plaf support
+ and lots of documenting, Lots of Free Swing and metal theme
+ additions. ``MetalIconFactory`` implementation.
+
+* Anthony Green for ``MIDI`` framework, ``ALSA`` and ``DSSI``
+ providers.
+
+* Andrew Haley for ``Serialization`` and ``URLClassLoader`` fixes,
+ gcj build speedups.
+
+* Kim Ho for ``JFileChooser`` implementation.
+
+* Andrew John Hughes for ``Locale`` and net fixes, URI RFC2986
+ updates, ``Serialization`` fixes, ``Properties`` XML support and
+ generic branch work, VMIntegration guide update.
+
+* Bastiaan Huisman for ``TimeZone`` bug fixing.
+
+* Andreas Jaeger for mprec updates.
+
+* Paul Jenner for better :option:`-Werror` support.
+
+* Ito Kazumitsu for ``NetworkInterface`` implementation and updates.
+
+* Roman Kennke for ``BoxLayout``, ``GrayFilter`` and
+ ``SplitPane``, plus bug fixes all over. Lots of Free Swing work
+ including styled text.
+
+* Simon Kitching for ``String`` cleanups and optimization suggestions.
+
+* Michael Koch for configuration fixes, ``Locale`` updates, bug and
+ build fixes.
+
+* Guilhem Lavaux for configuration, thread and channel fixes and Kaffe
+ integration. JCL native ``Pointer`` updates. Logger bug fixes.
+
+* David Lichteblau for JCL support library global/local reference
+ cleanups.
+
+* Aaron Luchko for JDWP updates and documentation fixes.
+
+* Ziga Mahkovec for ``Graphics2D`` upgraded to Cairo 0.5 and new regex
+ features.
+
+* Sven de Marothy for BMP imageio support, CSS and ``TextLayout``
+ fixes. ``GtkImage`` rewrite, 2D, awt, free swing and date/time fixes and
+ implementing the Qt4 peers.
+
+* Casey Marshall for crypto algorithm fixes, ``FileChannel`` lock,
+ ``SystemLogger`` and ``FileHandler`` rotate implementations, NIO
+ ``FileChannel.map`` support, security and policy updates.
+
+* Bryce McKinlay for RMI work.
+
+* Audrius Meskauskas for lots of Free Corba, RMI and HTML work plus
+ testing and documenting.
+
+* Kalle Olavi Niemitalo for build fixes.
+
+* Rainer Orth for build fixes.
+
+* Andrew Overholt for ``File`` locking fixes.
+
+* Ingo Proetel for ``Image``, ``Logger`` and ``URLClassLoader``
+ updates.
+
+* Olga Rodimina for ``MenuSelectionManager`` implementation.
+
+* Jan Roehrich for ``BasicTreeUI`` and ``JTree`` fixes.
+
+* Julian Scheid for documentation updates and gjdoc support.
+
+* Christian Schlichtherle for zip fixes and cleanups.
+
+* Robert Schuster for documentation updates and beans fixes,
+ ``TreeNode`` enumerations and ``ActionCommand`` and various
+ fixes, XML and URL, AWT and Free Swing bug fixes.
+
+* Keith Seitz for lots of JDWP work.
+
+* Christian Thalinger for 64-bit cleanups, Configuration and VM
+ interface fixes and ``CACAO`` integration, ``fdlibm`` updates.
+
+* Gael Thomas for ``VMClassLoader`` boot packages support suggestions.
+
+* Andreas Tobler for Darwin and Solaris testing and fixing, ``Qt4``
+ support for Darwin/OS X, ``Graphics2D`` support, ``gtk+``
+ updates.
+
+* Dalibor Topic for better ``DEBUG`` support, build cleanups and
+ Kaffe integration. ``Qt4`` build infrastructure, ``SHA1PRNG``
+ and ``GdkPixbugDecoder`` updates.
+
+* Tom Tromey for Eclipse integration, generics work, lots of bug fixes
+ and gcj integration including coordinating The Big Merge.
+
+* Mark Wielaard for bug fixes, packaging and release management,
+ ``Clipboard`` implementation, system call interrupts and network
+ timeouts and ``GdkPixpufDecoder`` fixes.
+
+In addition to the above, all of which also contributed time and energy in
+testing GCC, we would like to thank the following for their contributions
+to testing:
+
+* Michael Abd-El-Malek
+
+* Thomas Arend
+
+* Bonzo Armstrong
+
+* Steven Ashe
+
+* Chris Baldwin
+
+* David Billinghurst
+
+* Jim Blandy
+
+* Stephane Bortzmeyer
+
+* Horst von Brand
+
+* Frank Braun
+
+* Rodney Brown
+
+* Sidney Cadot
+
+* Bradford Castalia
+
+* Robert Clark
+
+* Jonathan Corbet
+
+* Ralph Doncaster
+
+* Richard Emberson
+
+* Levente Farkas
+
+* Graham Fawcett
+
+* Mark Fernyhough
+
+* Robert A. French
+
+* Jörgen Freyh
+
+* Mark K. Gardner
+
+* Charles-Antoine Gauthier
+
+* Yung Shing Gene
+
+* David Gilbert
+
+* Simon Gornall
+
+* Fred Gray
+
+* John Griffin
+
+* Patrik Hagglund
+
+* Phil Hargett
+
+* Amancio Hasty
+
+* Takafumi Hayashi
+
+* Bryan W. Headley
+
+* Kevin B. Hendricks
+
+* Joep Jansen
+
+* Christian Joensson
+
+* Michel Kern
+
+* David Kidd
+
+* Tobias Kuipers
+
+* Anand Krishnaswamy
+
+* A. O. V. Le Blanc
+
+* llewelly
+
+* Damon Love
+
+* Brad Lucier
+
+* Matthias Klose
+
+* Martin Knoblauch
+
+* Rick Lutowski
+
+* Jesse Macnish
+
+* Stefan Morrell
+
+* Anon A. Mous
+
+* Matthias Mueller
+
+* Pekka Nikander
+
+* Rick Niles
+
+* Jon Olson
+
+* Magnus Persson
+
+* Chris Pollard
+
+* Richard Polton
+
+* Derk Reefman
+
+* David Rees
+
+* Paul Reilly
+
+* Tom Reilly
+
+* Torsten Rueger
+
+* Danny Sadinoff
+
+* Marc Schifer
+
+* Erik Schnetter
+
+* Wayne K. Schroll
+
+* David Schuler
+
+* Vin Shelton
+
+* Tim Souder
+
+* Adam Sulmicki
+
+* Bill Thorson
+
+* George Talbot
+
+* Pedro A. M. Vazquez
+
+* Gregory Warnes
+
+* Ian Watson
+
+* David E. Young
+
+* And many others
+
+And finally we'd like to thank everyone who uses the compiler, provides
+feedback and generally reminds us why we're doing this work in the first
+place.
+
+.. -
+ Indexes
+ -
\ No newline at end of file
diff --git a/doc/contribute.rst b/doc/contribute.rst
new file mode 100644
index 00000000000..45e0c5f340c
--- /dev/null
+++ b/doc/contribute.rst
@@ -0,0 +1,26 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _contributing:
+
+Contributing to GCC Development
+-------------------------------
+
+If you would like to help pretest GCC releases to assure they work well,
+current development sources are available via Git (see
+http://gcc.gnu.org/git.html). Source and binary snapshots are
+also available for FTP; see http://gcc.gnu.org/snapshots.html.
+
+If you would like to work on improvements to GCC, please read the
+advice at these URLs:
+
+.. code-block:: c++
+
+ http://gcc.gnu.org/contribute.html
+ http://gcc.gnu.org/contributewhy.html
+
+for information on how to make useful contributions and avoid
+duplication of effort. Suggested projects are listed at
+http://gcc.gnu.org/projects/.
\ No newline at end of file
diff --git a/doc/copyright.rst b/doc/copyright.rst
new file mode 100644
index 00000000000..c28243a85e2
--- /dev/null
+++ b/doc/copyright.rst
@@ -0,0 +1,25 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+Copyright
+^^^^^^^^^
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.3 or
+any later version published by the Free Software Foundation; with the
+Invariant Sections being **GNU General Public License** and
+**Funding Free Software**, the Front-Cover texts being (a) (see below), and with
+the Back-Cover Texts being (b) (see below). A copy of the license is
+included in the gfdl(7) man page.
+
+(a) The FSF's Front-Cover Text is:
+
+ A GNU Manual
+
+(b) The FSF's Back-Cover Text is:
+
+ You have freedom to copy and modify this GNU Manual, like GNU
+ software. Copies published by the Free Software Foundation raise
+ funds for GNU development.
\ No newline at end of file
diff --git a/doc/cppdiropts.rst b/doc/cppdiropts.rst
new file mode 100644
index 00000000000..d00f69f67b9
--- /dev/null
+++ b/doc/cppdiropts.rst
@@ -0,0 +1,215 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. option:: -I dir, -iquote dir, -isystem dir, -idirafter dir
+
+ Add the directory :samp:`{dir}` to the list of directories to be searched
+ for header files during preprocessing.
+
+ .. only:: cpp
+
+ See :ref:`search-path`.
+
+ If :samp:`{dir}` begins with :samp:`=` or ``$SYSROOT``, then the :samp:`=`
+ or ``$SYSROOT`` is replaced by the sysroot prefix; see
+ :option:`--sysroot` and :option:`-isysroot`.
+
+ Directories specified with :option:`-iquote` apply only to the quote
+ form of the directive, ``#include "file"``.
+ Directories specified with :option:`-I`, :option:`-isystem`,
+ or :option:`-idirafter` apply to lookup for both the
+ ``#include "file"`` and
+ ``#include <file>`` directives.
+
+ You can specify any number or combination of these options on the
+ command line to search for header files in several directories.
+ The lookup order is as follows:
+
+ * For the quote form of the include directive, the directory of the current
+ file is searched first.
+
+ * For the quote form of the include directive, the directories specified
+ by :option:`-iquote` options are searched in left-to-right order,
+ as they appear on the command line.
+
+ * Directories specified with :option:`-I` options are scanned in
+ left-to-right order.
+
+ * Directories specified with :option:`-isystem` options are scanned in
+ left-to-right order.
+
+ * Standard system directories are scanned.
+
+ * Directories specified with :option:`-idirafter` options are scanned in
+ left-to-right order.
+
+ You can use :option:`-I` to override a system header
+ file, substituting your own version, since these directories are
+ searched before the standard system header file directories.
+ However, you should
+ not use this option to add directories that contain vendor-supplied
+ system header files; use :option:`-isystem` for that.
+
+ The :option:`-isystem` and :option:`-idirafter` options also mark the directory
+ as a system directory, so that it gets the same special treatment that
+ is applied to the standard system directories.
+
+ .. only:: cpp
+
+ See :ref:`system-headers`.
+
+
+ If a standard system include directory, or a directory specified with
+ :option:`-isystem`, is also specified with :option:`-I`, the :option:`-I`
+ option is ignored. The directory is still searched but as a
+ system directory at its normal position in the system include chain.
+ This is to ensure that GCC's procedure to fix buggy system headers and
+ the ordering for the ``#include_next`` directive are not inadvertently
+ changed.
+ If you really need to change the search order for system directories,
+ use the :option:`-nostdinc` and/or :option:`-isystem` options.
+
+ .. only:: cpp
+
+ See :ref:`system-headers`.
+
+
+.. option:: -I-
+
+ Split the include path.
+ This option has been deprecated. Please use :option:`-iquote` instead for
+ :option:`-I` directories before the :option:`-I-` and remove the :option:`-I-`
+ option.
+
+ Any directories specified with :option:`-I`
+ options before :option:`-I-` are searched only for headers requested with
+ ``#include "file"`` ; they are not searched for
+ ``#include <file>``. If additional directories are
+ specified with :option:`-I` options after the :option:`-I-`, those
+ directories are searched for all :samp:`#include` directives.
+
+ In addition, :option:`-I-` inhibits the use of the directory of the current
+ file directory as the first search directory for ``#include
+ "file"``. There is no way to override this effect of :option:`-I-`.
+
+ .. only:: cpp
+
+ See :ref:`search-path`.
+
+
+.. option:: -iprefix prefix
+
+ Specify :samp:`{prefix}` as the prefix for subsequent :option:`-iwithprefix`
+ options. If the prefix represents a directory, you should include the
+ final :samp:`/`.
+
+.. option:: -iwithprefix dir, -iwithprefixbefore dir
+
+ Append :samp:`{dir}` to the prefix specified previously with
+ :option:`-iprefix`, and add the resulting directory to the include search
+ path. :option:`-iwithprefixbefore` puts it in the same place :option:`-I`
+ would; :option:`-iwithprefix` puts it where :option:`-idirafter` would.
+
+.. option:: -isysroot dir
+
+ This option is like the :option:`--sysroot` option, but applies only to
+ header files (except for Darwin targets, where it applies to both header
+ files and libraries). See the :option:`--sysroot` option for more
+ information.
+
+.. option:: -imultilib dir
+
+ Use :samp:`{dir}` as a subdirectory of the directory containing
+ target-specific C++ headers.
+
+.. option:: -nostdinc
+
+ Do not search the standard system directories for header files.
+ Only the directories explicitly specified with :option:`-I`,
+ :option:`-iquote`, :option:`-isystem`, and/or :option:`-idirafter`
+ options (and the directory of the current file, if appropriate)
+ are searched.
+
+.. option:: -nostdinc++
+
+ Do not search for header files in the C++-specific standard directories,
+ but do still search the other standard directories. (This option is
+ used when building the C++ library.)
+
+.. option:: -Wcomment, -Wcomments
+
+ Warn whenever a comment-start sequence :samp:`/*` appears in a :samp:`/*`
+ comment, or whenever a backslash-newline appears in a :samp:`//` comment.
+ This warning is enabled by :option:`-Wall`.
+
+.. option:: -Wtrigraphs
+
+.. _wtrigraphs:
+
+ Warn if any trigraphs are encountered that might change the meaning of
+ the program. Trigraphs within comments are not warned about,
+ except those that would form escaped newlines.
+
+ This option is implied by :option:`-Wall`. If :option:`-Wall` is not
+ given, this option is still enabled unless trigraphs are enabled. To
+ get trigraph conversion without warnings, but get the other
+ :option:`-Wall` warnings, use :samp:`-trigraphs -Wall -Wno-trigraphs`.
+
+.. option:: -Wundef
+
+ Warn if an undefined identifier is evaluated in an ``#if`` directive.
+ Such identifiers are replaced with zero.
+
+.. option:: -Wno-undef
+
+ Default option value for :option:`-Wundef`.
+
+.. option:: -Wexpansion-to-defined
+
+ Warn whenever :samp:`defined` is encountered in the expansion of a macro
+ (including the case where the macro is expanded by an :samp:`#if` directive).
+ Such usage is not portable.
+ This warning is also enabled by :option:`-Wpedantic` and :option:`-Wextra`.
+
+.. option:: -Wunused-macros
+
+ Warn about macros defined in the main file that are unused. A macro
+ is :dfn:`used` if it is expanded or tested for existence at least once.
+ The preprocessor also warns if the macro has not been used at the
+ time it is redefined or undefined.
+
+ Built-in macros, macros defined on the command line, and macros
+ defined in include files are not warned about.
+
+ *Note:* If a macro is actually used, but only used in skipped
+ conditional blocks, then the preprocessor reports it as unused. To avoid the
+ warning in such a case, you might improve the scope of the macro's
+ definition by, for example, moving it into the first skipped block.
+ Alternatively, you could provide a dummy use with something like:
+
+ .. code-block:: c++
+
+ #if defined the_macro_causing_the_warning
+ #endif
+
+.. option:: -Wno-endif-labels
+
+ Do not warn whenever an ``#else`` or an ``#endif`` are followed by text.
+ This sometimes happens in older programs with code of the form
+
+ .. code-block:: c++
+
+ #if FOO
+ ...
+ #else FOO
+ ...
+ #endif FOO
+
+ The second and third ``FOO`` should be in comments.
+ This warning is on by default.
+
+.. option:: -Wendif-labels
+
+ Default option value for :option:`-Wno-endif-labels`.
\ No newline at end of file
diff --git a/doc/cppenv.rst b/doc/cppenv.rst
new file mode 100644
index 00000000000..9d035bb1125
--- /dev/null
+++ b/doc/cppenv.rst
@@ -0,0 +1,97 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. envvar:: CPATH, C_INCLUDE_PATH, CPLUS_INCLUDE_PATH, OBJC_INCLUDE_PATH
+
+ .. Commented out until ObjC++ is part of GCC:
+ @itemx OBJCPLUS_INCLUDE_PATH
+
+ Each variable's value is a list of directories separated by a special
+ character, much like :envvar:`PATH`, in which to look for header files.
+ The special character, ``PATH_SEPARATOR``, is target-dependent and
+ determined at GCC build time. For Microsoft Windows-based targets it is a
+ semicolon, and for almost all other targets it is a colon.
+
+ :envvar:`CPATH` specifies a list of directories to be searched as if
+ specified with :option:`-I`, but after any paths given with :option:`-I`
+ options on the command line. This environment variable is used
+ regardless of which language is being preprocessed.
+
+ The remaining environment variables apply only when preprocessing the
+ particular language indicated. Each specifies a list of directories
+ to be searched as if specified with :option:`-isystem`, but after any
+ paths given with :option:`-isystem` options on the command line.
+
+ In all these variables, an empty element instructs the compiler to
+ search its current working directory. Empty elements can appear at the
+ beginning or end of a path. For instance, if the value of
+ :envvar:`CPATH` is ``:/special/include``, that has the same
+ effect as :samp:`-I. -I/special/include`.
+
+ .. only:: cpp
+
+ See also Search Path.
+
+.. envvar:: DEPENDENCIES_OUTPUT
+
+ .. index:: dependencies for make as output
+
+ If this variable is set, its value specifies how to output
+ dependencies for Make based on the non-system header files processed
+ by the compiler. System header files are ignored in the dependency
+ output.
+
+ The value of :envvar:`DEPENDENCIES_OUTPUT` can be just a file name, in
+ which case the Make rules are written to that file, guessing the target
+ name from the source file name. Or the value can have the form
+ :samp:`{file}{target}`, in which case the rules are written to
+ file :samp:`{file}` using :samp:`{target}` as the target name.
+
+ In other words, this environment variable is equivalent to combining
+ the options :option:`-MM` and :option:`-MF`
+
+ .. only:: cpp
+
+ (see :ref:`invocation`),
+
+ .. only:: not cpp
+
+ (see :ref:`preprocessor-options`),
+
+ with an optional :option:`-MT` switch too.
+
+.. envvar:: SUNPRO_DEPENDENCIES
+
+ .. index:: dependencies for make as output
+
+ This variable is the same as :envvar:`DEPENDENCIES_OUTPUT` (see above),
+ except that system header files are not ignored, so it implies
+ :option:`-M` rather than :option:`-MM`. However, the dependence on the
+ main input file is omitted.
+
+ .. only:: cpp
+
+ See :ref:`invocation`.
+
+ .. only:: not cpp
+
+ See :ref:`preprocessor-options`.
+
+.. envvar:: SOURCE_DATE_EPOCH
+
+ If this variable is set, its value specifies a UNIX timestamp to be
+ used in replacement of the current date and time in the ``__DATE__``
+ and ``__TIME__`` macros, so that the embedded timestamps become
+ reproducible.
+
+ The value of :envvar:`SOURCE_DATE_EPOCH` must be a UNIX timestamp,
+ defined as the number of seconds (excluding leap seconds) since
+ 01 Jan 1970 00:00:00 represented in ASCII; identical to the output of
+ ``date +%s`` on GNU/Linux and other systems that support the
+ ``%s`` extension in the ``date`` command.
+
+ The value should be a known timestamp such as the last modification
+ time of the source or package and it should be set by the build
+ process.
\ No newline at end of file
diff --git a/doc/cppopts.rst b/doc/cppopts.rst
new file mode 100644
index 00000000000..aed3d972d5f
--- /dev/null
+++ b/doc/cppopts.rst
@@ -0,0 +1,559 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. option:: -D name
+
+ Predefine :samp:`{name}` as a macro, with definition ``1``.
+
+:samp:`-D {name}={definition}`
+ The contents of :samp:`{definition}` are tokenized and processed as if
+ they appeared during translation phase three in a :samp:`#define`
+ directive. In particular, the definition is truncated by
+ embedded newline characters.
+
+ If you are invoking the preprocessor from a shell or shell-like
+ program you may need to use the shell's quoting syntax to protect
+ characters such as spaces that have a meaning in the shell syntax.
+
+ If you wish to define a function-like macro on the command line, write
+ its argument list with surrounding parentheses before the equals sign
+ (if any). Parentheses are meaningful to most shells, so you should
+ quote the option. With :command:`sh` and :command:`csh`,
+ :option:`-D'`:samp:`{name}` ( :samp:`{args...}` )= :samp:`{definition}` ' works.
+
+ :option:`-D` and :option:`-U` options are processed in the order they
+ are given on the command line. All :option:`-imacros` :samp:`{file}` and
+ :option:`-include` :samp:`{file}` options are processed after all
+ :option:`-D` and :option:`-U` options.
+
+.. option:: -U name
+
+ Cancel any previous definition of :samp:`{name}`, either built in or
+ provided with a :option:`-D` option.
+
+.. option:: -include file
+
+ Process :samp:`{file}` as if ``#include "file"`` appeared as the first
+ line of the primary source file. However, the first directory searched
+ for :samp:`{file}` is the preprocessor's working directory *instead of*
+ the directory containing the main source file. If not found there, it
+ is searched for in the remainder of the ``#include "..."`` search
+ chain as normal.
+
+ If multiple :option:`-include` options are given, the files are included
+ in the order they appear on the command line.
+
+.. option:: -imacros file
+
+ Exactly like :option:`-include`, except that any output produced by
+ scanning :samp:`{file}` is thrown away. Macros it defines remain defined.
+ This allows you to acquire all the macros from a header without also
+ processing its declarations.
+
+ All files specified by :option:`-imacros` are processed before all files
+ specified by :option:`-include`.
+
+.. option:: -undef
+
+ Do not predefine any system-specific or GCC-specific macros. The
+ standard predefined macros remain defined.
+
+ .. only:: cpp
+
+ See :ref:`standard-predefined-macros`.
+
+.. option:: -pthread
+
+ Define additional macros required for using the POSIX threads library.
+ You should use this option consistently for both compilation and linking.
+ This option is supported on GNU/Linux targets, most other Unix derivatives,
+ and also on x86 Cygwin and MinGW targets.
+
+.. option:: -M
+
+ .. index:: make
+
+ .. index:: dependencies, make
+
+ Instead of outputting the result of preprocessing, output a rule
+ suitable for :command:`make` describing the dependencies of the main
+ source file. The preprocessor outputs one :command:`make` rule containing
+ the object file name for that source file, a colon, and the names of all
+ the included files, including those coming from :option:`-include` or
+ :option:`-imacros` command-line options.
+
+ Unless specified explicitly (with :option:`-MT` or :option:`-MQ` ), the
+ object file name consists of the name of the source file with any
+ suffix replaced with object file suffix and with any leading directory
+ parts removed. If there are many included files then the rule is
+ split into several lines using :samp:`\\` -newline. The rule has no
+ commands.
+
+ This option does not suppress the preprocessor's debug output, such as
+ :option:`-dM`. To avoid mixing such debug output with the dependency
+ rules you should explicitly specify the dependency output file with
+ :option:`-MF`, or use an environment variable like
+ :envvar:`DEPENDENCIES_OUTPUT` (see :ref:`environment-variables`). Debug output
+ is still sent to the regular output stream as normal.
+
+ Passing :option:`-M` to the driver implies :option:`-E`, and suppresses
+ warnings with an implicit :option:`-w`.
+
+.. option:: -MM
+
+ Like :option:`-M` but do not mention header files that are found in
+ system header directories, nor header files that are included,
+ directly or indirectly, from such a header.
+
+ This implies that the choice of angle brackets or double quotes in an
+ :samp:`#include` directive does not in itself determine whether that
+ header appears in :option:`-MM` dependency output.
+
+.. option:: -MF file
+
+ When used with :option:`-M` or :option:`-MM`, specifies a
+ file to write the dependencies to. If no :option:`-MF` switch is given
+ the preprocessor sends the rules to the same place it would send
+ preprocessed output.
+
+ When used with the driver options :option:`-MD` or :option:`-MMD`,
+ :option:`-MF` overrides the default dependency output file.
+
+ If :samp:`{file}` is :samp:`-`, then the dependencies are written to :samp:`stdout`.
+
+.. option:: -MG
+
+ In conjunction with an option such as :option:`-M` requesting
+ dependency generation, :option:`-MG` assumes missing header files are
+ generated files and adds them to the dependency list without raising
+ an error. The dependency filename is taken directly from the
+ ``#include`` directive without prepending any path. :option:`-MG`
+ also suppresses preprocessed output, as a missing header file renders
+ this useless.
+
+ This feature is used in automatic updating of makefiles.
+
+.. option:: -Mno-modules
+
+ Disable dependency generation for compiled module interfaces.
+
+.. option:: -MP
+
+ This option instructs CPP to add a phony target for each dependency
+ other than the main file, causing each to depend on nothing. These
+ dummy rules work around errors :command:`make` gives if you remove header
+ files without updating the :samp:`Makefile` to match.
+
+ This is typical output:
+
+ .. code-block:: c++
+
+ test.o: test.c test.h
+
+ test.h:
+
+.. option:: -MT target
+
+ Change the target of the rule emitted by dependency generation. By
+ default CPP takes the name of the main input file, deletes any
+ directory components and any file suffix such as :samp:`.c`, and
+ appends the platform's usual object suffix. The result is the target.
+
+ An :option:`-MT` option sets the target to be exactly the string you
+ specify. If you want multiple targets, you can specify them as a single
+ argument to :option:`-MT`, or use multiple :option:`-MT` options.
+
+ For example, -MT '$(objpfx)foo.o' might give
+
+ .. code-block:: c++
+
+ $(objpfx)foo.o: foo.c
+
+.. option:: -MQ target
+
+ Same as :option:`-MT`, but it quotes any characters which are special to
+ Make. -MQ '$(objpfx)foo.o' gives
+
+ .. code-block:: c++
+
+ $$(objpfx)foo.o: foo.c
+
+ The default target is automatically quoted, as if it were given with
+ :option:`-MQ`.
+
+.. option:: -MD
+
+ :option:`-MD` is equivalent to :option:`-M -MF` :samp:`{file}`, except that
+ :option:`-E` is not implied. The driver determines :samp:`{file}` based on
+ whether an :option:`-o` option is given. If it is, the driver uses its
+ argument but with a suffix of :samp:`.d`, otherwise it takes the name
+ of the input file, removes any directory components and suffix, and
+ applies a :samp:`.d` suffix.
+
+ If :option:`-MD` is used in conjunction with :option:`-E`, any
+ :option:`-o` switch is understood to specify the dependency output file
+ (see :ref:`-MF <dashmf>`), but if used without :option:`-E`, each :option:`-o`
+ is understood to specify a target object file.
+
+ Since :option:`-E` is not implied, :option:`-MD` can be used to generate
+ a dependency output file as a side effect of the compilation process.
+
+.. option:: -MMD
+
+ Like :option:`-MD` except mention only user header files, not system
+ header files.
+
+.. option:: -fpreprocessed
+
+ Indicate to the preprocessor that the input file has already been
+ preprocessed. This suppresses things like macro expansion, trigraph
+ conversion, escaped newline splicing, and processing of most directives.
+ The preprocessor still recognizes and removes comments, so that you can
+ pass a file preprocessed with :option:`-C` to the compiler without
+ problems. In this mode the integrated preprocessor is little more than
+ a tokenizer for the front ends.
+
+ :option:`-fpreprocessed` is implicit if the input file has one of the
+ extensions :samp:`.i`, :samp:`.ii` or :samp:`.mi`. These are the
+ extensions that GCC uses for preprocessed files created by
+ :option:`-save-temps`.
+
+.. option:: -fdirectives-only
+
+ When preprocessing, handle directives, but do not expand macros.
+
+ The option's behavior depends on the :option:`-E` and :option:`-fpreprocessed`
+ options.
+
+ With :option:`-E`, preprocessing is limited to the handling of directives
+ such as ``#define``, ``#ifdef``, and ``#error``. Other
+ preprocessor operations, such as macro expansion and trigraph
+ conversion are not performed. In addition, the :option:`-dD` option is
+ implicitly enabled.
+
+ With :option:`-fpreprocessed`, predefinition of command line and most
+ builtin macros is disabled. Macros such as ``__LINE__``, which are
+ contextually dependent, are handled normally. This enables compilation of
+ files previously preprocessed with ``-E -fdirectives-only``.
+
+ With both :option:`-E` and :option:`-fpreprocessed`, the rules for
+ :option:`-fpreprocessed` take precedence. This enables full preprocessing of
+ files previously preprocessed with ``-E -fdirectives-only``.
+
+.. option:: -fdollars-in-identifiers
+
+.. _fdollars-in-identifiers:
+
+ Accept :samp:`$` in identifiers.
+
+ .. only:: cpp
+
+ See :ref:`identifier-characters`.
+
+.. option:: -fextended-identifiers
+
+ Accept universal character names and extended characters in
+ identifiers. This option is enabled by default for C99 (and later C
+ standard versions) and C++.
+
+.. option:: -fno-canonical-system-headers
+
+ When preprocessing, do not shorten system header paths with canonicalization.
+
+.. option:: -fmax-include-depth=depth
+
+ Set the maximum depth of the nested #include. The default is 200.
+
+.. option:: -ftabstop=width
+
+ Set the distance between tab stops. This helps the preprocessor report
+ correct column numbers in warnings or errors, even if tabs appear on the
+ line. If the value is less than 1 or greater than 100, the option is
+ ignored. The default is 8.
+
+.. option:: -ftrack-macro-expansion[=level]
+
+ Track locations of tokens across macro expansions. This allows the
+ compiler to emit diagnostic about the current macro expansion stack
+ when a compilation error occurs in a macro expansion. Using this
+ option makes the preprocessor and the compiler consume more
+ memory. The :samp:`{level}` parameter can be used to choose the level of
+ precision of token location tracking thus decreasing the memory
+ consumption if necessary. Value :samp:`0` of :samp:`{level}` de-activates
+ this option. Value :samp:`1` tracks tokens locations in a
+ degraded mode for the sake of minimal memory overhead. In this mode
+ all tokens resulting from the expansion of an argument of a
+ function-like macro have the same location. Value :samp:`2` tracks
+ tokens locations completely. This value is the most memory hungry.
+ When this option is given no argument, the default parameter value is
+ :samp:`2`.
+
+ Note that ``-ftrack-macro-expansion=2`` is activated by default.
+
+.. option:: -fmacro-prefix-map=old=new
+
+ When preprocessing files residing in directory :samp:`{old}`,
+ expand the ``__FILE__`` and ``__BASE_FILE__`` macros as if the
+ files resided in directory :samp:`{new}` instead. This can be used
+ to change an absolute path to a relative path by using :samp:`.` for
+ :samp:`{new}` which can result in more reproducible builds that are
+ location independent. This option also affects
+ ``__builtin_FILE()`` during compilation. See also
+ :option:`-ffile-prefix-map`.
+
+.. option:: -fexec-charset=charset
+
+ .. index:: character set, execution
+
+ Set the execution character set, used for string and character
+ constants. The default is UTF-8. :samp:`{charset}` can be any encoding
+ supported by the system's ``iconv`` library routine.
+
+.. option:: -fwide-exec-charset=charset
+
+ .. index:: character set, wide execution
+
+ Set the wide execution character set, used for wide string and
+ character constants. The default is UTF-32 or UTF-16, whichever
+ corresponds to the width of ``wchar_t``. As with
+ :option:`-fexec-charset`, :samp:`{charset}` can be any encoding supported
+ by the system's ``iconv`` library routine; however, you will have
+ problems with encodings that do not fit exactly in ``wchar_t``.
+
+.. option:: -finput-charset=charset
+
+ .. index:: character set, input
+
+ Set the input character set, used for translation from the character
+ set of the input file to the source character set used by GCC. If the
+ locale does not specify, or GCC cannot get this information from the
+ locale, the default is UTF-8. This can be overridden by either the locale
+ or this command-line option. Currently the command-line option takes
+ precedence if there's a conflict. :samp:`{charset}` can be any encoding
+ supported by the system's ``iconv`` library routine.
+
+.. only:: not cpp
+
+ .. option:: -fpch-deps
+
+ When using precompiled headers (see :ref:`precompiled-headers`), this flag
+ causes the dependency-output flags to also list the files from the
+ precompiled header's dependencies. If not specified, only the
+ precompiled header are listed and not the files that were used to
+ create it, because those files are not consulted when a precompiled
+ header is used.
+
+ .. option:: -fpch-preprocess
+
+ This option allows use of a precompiled header (see :ref:`precompiled-headers`) together with :option:`-E`. It inserts a special ``#pragma``,
+ ``#pragma GCC pch_preprocess "filename"`` in the output to mark
+ the place where the precompiled header was found, and its :samp:`{filename}`.
+ When :option:`-fpreprocessed` is in use, GCC recognizes this ``#pragma``
+ and loads the PCH.
+
+ This option is off by default, because the resulting preprocessed output
+ is only really suitable as input to GCC. It is switched on by
+ :option:`-save-temps`.
+
+ You should not write this ``#pragma`` in your own code, but it is
+ safe to edit the filename if the PCH file is available in a different
+ location. The filename may be absolute or it may be relative to GCC's
+ current directory.
+
+.. option:: -fworking-directory
+
+ Enable generation of linemarkers in the preprocessor output that
+ let the compiler know the current working directory at the time of
+ preprocessing. When this option is enabled, the preprocessor
+ emits, after the initial linemarker, a second linemarker with the
+ current working directory followed by two slashes. GCC uses this
+ directory, when it's present in the preprocessed input, as the
+ directory emitted as the current working directory in some debugging
+ information formats. This option is implicitly enabled if debugging
+ information is enabled, but this can be inhibited with the negated
+ form :option:`-fno-working-directory`. If the :option:`-P` flag is
+ present in the command line, this option has no effect, since no
+ ``#line`` directives are emitted whatsoever.
+
+.. option:: -fno-working-directory
+
+ Default option value for :option:`-fworking-directory`.
+
+.. option:: -A predicate=answer
+
+ Make an assertion with the predicate :samp:`{predicate}` and answer
+ :samp:`{answer}`. This form is preferred to the older form :option:`-A`
+ :samp:`{predicate}` ( :samp:`{answer}` ), which is still supported, because
+ it does not use shell special characters.
+
+ .. only:: cpp
+
+ See :ref:`obsolete-features`.
+
+:samp:`-A -{predicate}={answer}`
+ Cancel an assertion with the predicate :samp:`{predicate}` and answer
+ :samp:`{answer}`.
+
+.. option:: -C
+
+ Do not discard comments. All comments are passed through to the output
+ file, except for comments in processed directives, which are deleted
+ along with the directive.
+
+ You should be prepared for side effects when using :option:`-C` ; it
+ causes the preprocessor to treat comments as tokens in their own right.
+ For example, comments appearing at the start of what would be a
+ directive line have the effect of turning that line into an ordinary
+ source line, since the first token on the line is no longer a :samp:`#`.
+
+.. option:: -CC
+
+ Do not discard comments, including during macro expansion. This is
+ like :option:`-C`, except that comments contained within macros are
+ also passed through to the output file where the macro is expanded.
+
+ In addition to the side effects of the :option:`-C` option, the
+ :option:`-CC` option causes all C++-style comments inside a macro
+ to be converted to C-style comments. This is to prevent later use
+ of that macro from inadvertently commenting out the remainder of
+ the source line.
+
+ The :option:`-CC` option is generally used to support lint comments.
+
+.. option:: -P
+
+ Inhibit generation of linemarkers in the output from the preprocessor.
+ This might be useful when running the preprocessor on something that is
+ not C code, and will be sent to a program which might be confused by the
+ linemarkers.
+
+ .. only:: cpp
+
+ See :ref:`preprocessor-output`.
+
+ .. index:: traditional C language
+
+ .. index:: C language, traditional
+
+.. option:: -traditional, -traditional-cpp
+
+ Try to imitate the behavior of pre-standard C preprocessors, as
+ opposed to ISO C preprocessors.
+
+ .. only:: cpp
+
+ See :ref:`traditional-mode`.
+
+ .. only:: not cpp
+
+ See the GNU CPP manual for details.
+
+ Note that GCC does not otherwise attempt to emulate a pre-standard
+ C compiler, and these options are only supported with the :option:`-E`
+ switch, or when invoking CPP explicitly.
+
+.. option:: -trigraphs
+
+ Support ISO C trigraphs.
+ These are three-character sequences, all starting with :samp:`??`, that
+ are defined by ISO C to stand for single characters. For example,
+ :samp:`??/` stands for :samp:`\\`, so :samp:`??/n` is a character
+ constant for a newline.
+
+ .. only:: cpp
+
+ See :ref:`initial-processing`.
+
+ .. only:: not cpp
+
+ The nine trigraphs and their replacements are
+
+ .. code-block::
+
+ Trigraph: ??( ??) ??< ??> ??= ??/ ??' ??! ??-
+ Replacement: [ ] { } # \ ^ | ~
+
+ By default, GCC ignores trigraphs, but in
+ standard-conforming modes it converts them. See the :option:`-std` and
+ :option:`-ansi` options.
+
+.. option:: -remap
+
+ Enable special code to work around file systems which only permit very
+ short file names, such as MS-DOS.
+
+.. option:: -H
+
+ Print the name of each header file used, in addition to other normal
+ activities. Each name is indented to show how deep in the
+ :samp:`#include` stack it is. Precompiled header files are also
+ printed, even if they are found to be invalid; an invalid precompiled
+ header file is printed with :samp:`...x` and a valid one with :samp:`...!` .
+
+.. option:: -dletters
+
+ Says to make debugging dumps during compilation as specified by
+ :samp:`{letters}`. The flags documented here are those relevant to the
+ preprocessor. Other :samp:`{letters}` are interpreted
+ by the compiler proper, or reserved for future versions of GCC, and so
+ are silently ignored. If you specify :samp:`{letters}` whose behavior
+ conflicts, the result is undefined.
+
+ .. only:: not cpp
+
+ See :ref:`developer-options`, for more information.
+
+ .. option:: -dM
+
+ Instead of the normal output, generate a list of :samp:`#define`
+ directives for all the macros defined during the execution of the
+ preprocessor, including predefined macros. This gives you a way of
+ finding out what is predefined in your version of the preprocessor.
+ Assuming you have no file :samp:`foo.h`, the command
+
+ .. code-block:: c++
+
+ touch foo.h; cpp -dM foo.h
+
+ shows all the predefined macros.
+
+ .. only:: cpp
+
+ If you use :option:`-dM` without the :option:`-E` option, :option:`-dM` is
+ interpreted as a synonym for :option:`-fdump-rtl-mach`.
+ See :ref:`developer-options`.
+
+ .. option:: -dD
+
+ Like :option:`-dM` except in two respects: it does *not* include the
+ predefined macros, and it outputs *both* the :samp:`#define`
+ directives and the result of preprocessing. Both kinds of output go to
+ the standard output file.
+
+ .. option:: -dN
+
+ Like :option:`-dD`, but emit only the macro names, not their expansions.
+
+ .. option:: -dI
+
+ Output :samp:`#include` directives in addition to the result of
+ preprocessing.
+
+ .. option:: -dU
+
+ Like :option:`-dD` except that only macros that are expanded, or whose
+ definedness is tested in preprocessor directives, are output; the
+ output is delayed until the use or test of the macro; and
+ :samp:`#undef` directives are also output for macros tested but
+ undefined at the time.
+
+.. option:: -fdebug-cpp
+
+ This option is only useful for debugging GCC. When used from CPP or with
+ :option:`-E`, it dumps debugging information about location maps. Every
+ token in the output is preceded by the dump of the map its location
+ belongs to.
+
+ When used from GCC without :option:`-E`, this option has no effect.
\ No newline at end of file
diff --git a/doc/cppwarnopts.rst b/doc/cppwarnopts.rst
new file mode 100644
index 00000000000..4814ff34eb9
--- /dev/null
+++ b/doc/cppwarnopts.rst
@@ -0,0 +1,4 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
\ No newline at end of file
diff --git a/doc/funding.rst b/doc/funding.rst
new file mode 100644
index 00000000000..245e3d4bf22
--- /dev/null
+++ b/doc/funding.rst
@@ -0,0 +1,47 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+Funding Free Software
+=====================
+
+If you want to have more free software a few years from now, it makes
+sense for you to help encourage people to contribute funds for its
+development. The most effective approach known is to encourage
+commercial redistributors to donate.
+
+Users of free software systems can boost the pace of development by
+encouraging for-a-fee distributors to donate part of their selling price
+to free software developers-the Free Software Foundation, and others.
+
+The way to convince distributors to do this is to demand it and expect
+it from them. So when you compare distributors, judge them partly by
+how much they give to free software development. Show distributors
+they must compete to be the one who gives the most.
+
+To make this approach work, you must insist on numbers that you can
+compare, such as, 'We will donate ten dollars to the Frobnitz project
+for each disk sold.' Don't be satisfied with a vague promise, such as
+'A portion of the profits are donated,' since it doesn't give a basis
+for comparison.
+
+Even a precise fraction 'of the profits from this disk' is not very
+meaningful, since creative accounting and unrelated business decisions
+can greatly alter what fraction of the sales price counts as profit.
+If the price you pay is $50, ten percent of the profit is probably
+less than a dollar; it might be a few cents, or nothing at all.
+
+Some redistributors do development work themselves. This is useful too;
+but to keep everyone honest, you need to inquire how much they do, and
+what kind. Some kinds of development make much more long-term
+difference than others. For example, maintaining a separate version of
+a program contributes very little; maintaining the standard version of a
+program for the whole community contributes much. Easy new ports
+contribute little, since someone else would surely do them; difficult
+ports such as adding a new CPU to the GNU Compiler Collection contribute more;
+major new features or packages contribute the most.
+
+By establishing the idea that supporting further development is 'the
+proper thing to do' when distributing free software for a fee, we can
+assure a steady flow of resources into making more free software.
\ No newline at end of file
diff --git a/doc/gnu.rst b/doc/gnu.rst
new file mode 100644
index 00000000000..8003f925c4c
--- /dev/null
+++ b/doc/gnu.rst
@@ -0,0 +1,24 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _gnu-project:
+
+The GNU Project and GNU/Linux
+=============================
+
+The GNU Project was launched in 1984 to develop a complete Unix-like
+operating system which is free software: the GNU system. (GNU is a
+recursive acronym for 'GNU's Not Unix'; it is pronounced
+'guh-NEW'.) Variants of the GNU operating system, which use the
+kernel Linux, are now widely used; though these systems are often
+referred to as 'Linux', they are more accurately called GNU/Linux
+systems.
+
+For more information, see:
+
+.. code-block:: c++
+
+ http://www.gnu.org/
+ http://www.gnu.org/gnu/linux-and-gnu.html
\ No newline at end of file
diff --git a/doc/gnu_free_documentation_license.rst b/doc/gnu_free_documentation_license.rst
new file mode 100644
index 00000000000..d12a088fc14
--- /dev/null
+++ b/doc/gnu_free_documentation_license.rst
@@ -0,0 +1,463 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _gnu_fdl:
+
+******************************
+GNU Free Documentation License
+******************************
+
+Version 1.3, 3 November 2008
+
+Copyright 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc
+http://fsf.org/
+
+Everyone is permitted to copy and distribute verbatim copies of this
+license document, but changing it is not allowed.
+
+**Preamble**
+
+The purpose of this License is to make a manual, textbook, or other
+functional and useful document "free" in the sense of freedom: to
+assure everyone the effective freedom to copy and redistribute it,
+with or without modifying it, either commercially or noncommercially.
+Secondarily, this License preserves for the author and publisher a way
+to get credit for their work, while not being considered responsible
+for modifications made by others.
+
+This License is a kind of "copyleft", which means that derivative
+works of the document must themselves be free in the same sense. It
+complements the GNU General Public License, which is a copyleft
+license designed for free software.
+
+We have designed this License in order to use it for manuals for free
+software, because free software needs free documentation: a free
+program should come with manuals providing the same freedoms that the
+software does. But this License is not limited to software manuals;
+it can be used for any textual work, regardless of subject matter or
+whether it is published as a printed book. We recommend this License
+principally for works whose purpose is instruction or reference.
+
+**1. APPLICABILITY AND DEFINITIONS**
+
+This License applies to any manual or other work, in any medium, that
+contains a notice placed by the copyright holder saying it can be
+distributed under the terms of this License. Such a notice grants a
+world-wide, royalty-free license, unlimited in duration, to use that
+work under the conditions stated herein. The **Document**, below,
+refers to any such manual or work. Any member of the public is a
+licensee, and is addressed as "**you**". You accept the license if you
+copy, modify or distribute the work in a way requiring permission
+under copyright law.
+
+A "**Modified Version**" of the Document means any work containing the
+Document or a portion of it, either copied verbatim, or with
+modifications and/or translated into another language.
+
+A "**Secondary Section**" is a named appendix or a front-matter section of
+the Document that deals exclusively with the relationship of the
+publishers or authors of the Document to the Document's overall subject
+(or to related matters) and contains nothing that could fall directly
+within that overall subject. (Thus, if the Document is in part a
+textbook of mathematics, a Secondary Section may not explain any
+mathematics.) The relationship could be a matter of historical
+connection with the subject or with related matters, or of legal,
+commercial, philosophical, ethical or political position regarding
+them.
+
+The "**Invariant Sections**" are certain Secondary Sections whose titles
+are designated, as being those of Invariant Sections, in the notice
+that says that the Document is released under this License. If a
+section does not fit the above definition of Secondary then it is not
+allowed to be designated as Invariant. The Document may contain zero
+Invariant Sections. If the Document does not identify any Invariant
+Sections then there are none.
+
+The "**Cover Texts**" are certain short passages of text that are listed,
+as Front-Cover Texts or Back-Cover Texts, in the notice that says that
+the Document is released under this License. A Front-Cover Text may
+be at most 5 words, and a Back-Cover Text may be at most 25 words.
+
+A "**Transparent**" copy of the Document means a machine-readable copy,
+represented in a format whose specification is available to the
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+drawing editor, and that is suitable for input to text formatters or
+for automatic translation to a variety of formats suitable for input
+to text formatters. A copy made in an otherwise Transparent file
+format whose markup, or absence of markup, has been arranged to thwart
+or discourage subsequent modification by readers is not Transparent.
+An image format is not Transparent if used for any substantial amount
+of text. A copy that is not "Transparent" is called **Opaque**.
+
+Examples of suitable formats for Transparent copies include plain
+ASCII without markup, Texinfo input format, LaTeX input format, SGML
+or XML using a publicly available DTD, and standard-conforming simple
+HTML, PostScript or PDF designed for human modification. Examples of
+transparent image formats include PNG, XCF and JPG. Opaque formats
+include proprietary formats that can be read and edited only by
+proprietary word processors, SGML or XML for which the DTD and/or
+processing tools are not generally available, and the
+machine-generated HTML, PostScript or PDF produced by some word
+processors for output purposes only.
+
+The "**Title Page**" means, for a printed book, the title page itself,
+plus such following pages as are needed to hold, legibly, the material
+this License requires to appear in the title page. For works in
+formats which do not have any title page as such, "Title Page" means
+the text near the most prominent appearance of the work's title,
+preceding the beginning of the body of the text.
+
+The "**publisher**" means any person or entity that distributes
+copies of the Document to the public.
+
+A section "**Entitled XYZ**" means a named subunit of the Document whose
+title either is precisely XYZ or contains XYZ in parentheses following
+text that translates XYZ in another language. (Here XYZ stands for a
+specific section name mentioned below, such as "**Acknowledgements**",
+"**Dedications**", "**Endorsements**", or "**History**".)
+To "**Preserve the Title**"
+of such a section when you modify the Document means that it remains a
+section "Entitled XYZ" according to this definition.
+
+The Document may include Warranty Disclaimers next to the notice which
+states that this License applies to the Document. These Warranty
+Disclaimers are considered to be included by reference in this
+License, but only as regards disclaiming warranties: any other
+implication that these Warranty Disclaimers may have is void and has
+no effect on the meaning of this License.
+
+**2. VERBATIM COPYING**
+
+You may copy and distribute the Document in any medium, either
+commercially or noncommercially, provided that this License, the
+copyright notices, and the license notice saying this License applies
+to the Document are reproduced in all copies, and that you add no other
+conditions whatsoever to those of this License. You may not use
+technical measures to obstruct or control the reading or further
+copying of the copies you make or distribute. However, you may accept
+compensation in exchange for copies. If you distribute a large enough
+number of copies you must also follow the conditions in section 3.
+
+You may also lend copies, under the same conditions stated above, and
+you may publicly display copies.
+
+**3. COPYING IN QUANTITY**
+
+If you publish printed copies (or copies in media that commonly have
+printed covers) of the Document, numbering more than 100, and the
+Document's license notice requires Cover Texts, you must enclose the
+copies in covers that carry, clearly and legibly, all these Cover
+Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
+the back cover. Both covers must also clearly and legibly identify
+you as the publisher of these copies. The front cover must present
+the full title with all words of the title equally prominent and
+visible. You may add other material on the covers in addition.
+Copying with changes limited to the covers, as long as they preserve
+the title of the Document and satisfy these conditions, can be treated
+as verbatim copying in other respects.
+
+If the required texts for either cover are too voluminous to fit
+legibly, you should put the first ones listed (as many as fit
+reasonably) on the actual cover, and continue the rest onto adjacent
+pages.
+
+If you publish or distribute Opaque copies of the Document numbering
+more than 100, you must either include a machine-readable Transparent
+copy along with each Opaque copy, or state in or with each Opaque copy
+a computer-network location from which the general network-using
+public has access to download using public-standard network protocols
+a complete Transparent copy of the Document, free of added material.
+If you use the latter option, you must take reasonably prudent steps,
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+that this Transparent copy will remain thus accessible at the stated
+location until at least one year after the last time you distribute an
+Opaque copy (directly or through your agents or retailers) of that
+edition to the public.
+
+It is requested, but not required, that you contact the authors of the
+Document well before redistributing any large number of copies, to give
+them a chance to provide you with an updated version of the Document.
+
+**4. MODIFICATIONS**
+
+You may copy and distribute a Modified Version of the Document under
+the conditions of sections 2 and 3 above, provided that you release
+the Modified Version under precisely this License, with the Modified
+Version filling the role of the Document, thus licensing distribution
+and modification of the Modified Version to whoever possesses a copy
+of it. In addition, you must do these things in the Modified Version:
+
+A. Use in the Title Page (and on the covers, if any) a title distinct
+ from that of the Document, and from those of previous versions
+ (which should, if there were any, be listed in the History section
+ of the Document). You may use the same title as a previous version
+ if the original publisher of that version gives permission.
+
+B. List on the Title Page, as authors, one or more persons or entities
+ responsible for authorship of the modifications in the Modified
+ Version, together with at least five of the principal authors of the
+ Document (all of its principal authors, if it has fewer than five),
+ unless they release you from this requirement.
+
+C. State on the Title page the name of the publisher of the
+ Modified Version, as the publisher.
+
+D. Preserve all the copyright notices of the Document.
+
+E. Add an appropriate copyright notice for your modifications
+ adjacent to the other copyright notices.
+
+F. Include, immediately after the copyright notices, a license notice
+ giving the public permission to use the Modified Version under the
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+distribution medium, is called an "aggregate" if the copyright
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+its Title (section 1) will typically require changing the actual
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+**9. TERMINATION**
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+You may not copy, modify, sublicense, or distribute the Document
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+will automatically terminate your rights under this License.
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+However, if you cease all violation of this License, then your license
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+not give you any rights to use it.
+
+**10. FUTURE REVISIONS OF THIS LICENSE**
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+The Free Software Foundation may publish new, revised versions
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+License "or any later version" applies to it, you have the option of
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+provided the MMC is eligible for relicensing.
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+**ADDENDUM: How to use this License for your documents**
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+To use this License in a document you have written, include a copy of
+the License in the document and put the following copyright and
+license notices just after the title page:
+
+ Copyright © YEAR YOUR NAME.
+ Permission is granted to copy, distribute and/or modify this document
+ under the terms of the GNU Free Documentation License, Version 1.3
+ or any later version published by the Free Software Foundation;
+ with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
+ A copy of the license is included in the section entitled "GNU
+ Free Documentation License".
+
+
+If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
+replace the "with ... Texts." line with this:
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+If your document contains nontrivial examples of program code, we
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+to permit their use in free software.
\ No newline at end of file
diff --git a/doc/gpl-3.0.rst b/doc/gpl-3.0.rst
new file mode 100644
index 00000000000..058a049da17
--- /dev/null
+++ b/doc/gpl-3.0.rst
@@ -0,0 +1,707 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+GNU GENERAL PUBLIC LICENSE
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Version 3, 29 June 2007
+
+Copyright (C) 2007 Free Software Foundation, Inc. https://fsf.org/
+
+Everyone is permitted to copy and distribute verbatim copies of this
+license document, but changing it is not allowed.
+
+Preamble
+########
+
+The GNU General Public License is a free, copyleft license for software
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+For example, if you distribute copies of such a program, whether gratis
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+TERMS AND CONDITIONS
+####################
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\ No newline at end of file
diff --git a/doc/lgpl-2.1.rst b/doc/lgpl-2.1.rst
new file mode 100644
index 00000000000..a4c346be676
--- /dev/null
+++ b/doc/lgpl-2.1.rst
@@ -0,0 +1,512 @@
+..
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\ No newline at end of file
diff --git a/doc/md.rst b/doc/md.rst
new file mode 100644
index 00000000000..e0b19b276c6
--- /dev/null
+++ b/doc/md.rst
@@ -0,0 +1,3272 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _simple-constraints:
+
+Simple Constraints
+^^^^^^^^^^^^^^^^^^
+
+.. index:: simple constraints
+
+The simplest kind of constraint is a string full of letters, each of
+which describes one kind of operand that is permitted. Here are
+the letters that are allowed:
+
+whitespace
+ Whitespace characters are ignored and can be inserted at any position
+ except the first. This enables each alternative for different operands to
+ be visually aligned in the machine description even if they have different
+ number of constraints and modifiers.
+
+ .. index:: m in constraint
+
+ .. index:: memory references in constraints
+
+m
+ A memory operand is allowed, with any kind of address that the machine
+ supports in general.
+ Note that the letter used for the general memory constraint can be
+ re-defined by a back end using the ``TARGET_MEM_CONSTRAINT`` macro.
+
+ .. index:: offsettable address
+
+ .. index:: o in constraint
+
+o
+ A memory operand is allowed, but only if the address is
+ :dfn:`offsettable`. This means that adding a small integer (actually,
+ the width in bytes of the operand, as determined by its machine mode)
+ may be added to the address and the result is also a valid memory
+ address.
+
+ .. index:: autoincrement/decrement addressing
+
+ For example, an address which is constant is offsettable; so is an
+ address that is the sum of a register and a constant (as long as a
+ slightly larger constant is also within the range of address-offsets
+ supported by the machine); but an autoincrement or autodecrement
+ address is not offsettable. More complicated indirect/indexed
+ addresses may or may not be offsettable depending on the other
+ addressing modes that the machine supports.
+
+ Note that in an output operand which can be matched by another
+ operand, the constraint letter :samp:`o` is valid only when accompanied
+ by both :samp:`<` (if the target machine has predecrement addressing)
+ and :samp:`>` (if the target machine has preincrement addressing).
+
+ .. index:: V in constraint
+
+V
+ A memory operand that is not offsettable. In other words, anything that
+ would fit the :samp:`m` constraint but not the :samp:`o` constraint.
+
+ .. index:: < in constraint
+
+<
+ A memory operand with autodecrement addressing (either predecrement or
+ postdecrement) is allowed. In inline ``asm`` this constraint is only
+ allowed if the operand is used exactly once in an instruction that can
+ handle the side effects. Not using an operand with :samp:`<` in constraint
+ string in the inline ``asm`` pattern at all or using it in multiple
+ instructions isn't valid, because the side effects wouldn't be performed
+ or would be performed more than once. Furthermore, on some targets
+ the operand with :samp:`<` in constraint string must be accompanied by
+ special instruction suffixes like ``%U0`` instruction suffix on PowerPC
+ or ``%P0`` on IA-64.
+
+ .. index:: > in constraint
+
+>
+ A memory operand with autoincrement addressing (either preincrement or
+ postincrement) is allowed. In inline ``asm`` the same restrictions
+ as for :samp:`<` apply.
+
+ .. index:: r in constraint
+
+ .. index:: registers in constraints
+
+r
+ A register operand is allowed provided that it is in a general
+ register.
+
+ .. index:: constants in constraints
+
+ .. index:: i in constraint
+
+i
+ An immediate integer operand (one with constant value) is allowed.
+ This includes symbolic constants whose values will be known only at
+ assembly time or later.
+
+ .. index:: n in constraint
+
+n
+ An immediate integer operand with a known numeric value is allowed.
+ Many systems cannot support assembly-time constants for operands less
+ than a word wide. Constraints for these operands should use :samp:`n`
+ rather than :samp:`i`.
+
+ .. index:: I in constraint
+
+:samp:`{I}, {J}, {K}, ... {P}`
+ Other letters in the range :samp:`I` through :samp:`P` may be defined in
+ a machine-dependent fashion to permit immediate integer operands with
+ explicit integer values in specified ranges. For example, on the
+ 68000, :samp:`I` is defined to stand for the range of values 1 to 8.
+ This is the range permitted as a shift count in the shift
+ instructions.
+
+ .. index:: E in constraint
+
+E
+ An immediate floating operand (expression code ``const_double`` ) is
+ allowed, but only if the target floating point format is the same as
+ that of the host machine (on which the compiler is running).
+
+ .. index:: F in constraint
+
+F
+ An immediate floating operand (expression code ``const_double`` or
+ ``const_vector`` ) is allowed.
+
+ .. index:: G in constraint
+
+ .. index:: H in constraint
+
+:samp:`{G}, {H}`
+ :samp:`G` and :samp:`H` may be defined in a machine-dependent fashion to
+ permit immediate floating operands in particular ranges of values.
+
+ .. index:: s in constraint
+
+s
+ An immediate integer operand whose value is not an explicit integer is
+ allowed.
+
+ This might appear strange; if an insn allows a constant operand with a
+ value not known at compile time, it certainly must allow any known
+ value. So why use :samp:`s` instead of :samp:`i`? Sometimes it allows
+ better code to be generated.
+
+ For example, on the 68000 in a fullword instruction it is possible to
+ use an immediate operand; but if the immediate value is between -128
+ and 127, better code results from loading the value into a register and
+ using the register. This is because the load into the register can be
+ done with a :samp:`moveq` instruction. We arrange for this to happen
+ by defining the letter :samp:`K` to mean 'any integer outside the
+ range -128 to 127', and then specifying :samp:`Ks` in the operand
+ constraints.
+
+ .. index:: g in constraint
+
+g
+ Any register, memory or immediate integer operand is allowed, except for
+ registers that are not general registers.
+
+ .. index:: X in constraint
+
+X
+
+ .. only:: gccint
+
+ Any operand whatsoever is allowed, even if it does not satisfy
+ ``general_operand``. This is normally used in the constraint of
+ a ``match_scratch`` when certain alternatives will not actually
+ require a scratch register.
+
+ .. only:: not gccint
+
+ Any operand whatsoever is allowed.
+
+ .. index:: 0 in constraint
+
+ .. index:: digits in constraint
+
+:samp:`{0}, {1}, {2}, ... {9}`
+ An operand that matches the specified operand number is allowed. If a
+ digit is used together with letters within the same alternative, the
+ digit should come last.
+
+ This number is allowed to be more than a single digit. If multiple
+ digits are encountered consecutively, they are interpreted as a single
+ decimal integer. There is scant chance for ambiguity, since to-date
+ it has never been desirable that :samp:`10` be interpreted as matching
+ either operand 1 *or* operand 0. Should this be desired, one
+ can use multiple alternatives instead.
+
+ .. index:: matching constraint
+
+ .. index:: constraint, matching
+
+ This is called a :dfn:`matching constraint` and what it really means is
+ that the assembler has only a single operand that fills two roles
+
+ .. only:: gccint
+
+ considered separate in the RTL insn. For example, an add insn has two
+ input operands and one output operand in the RTL, but on most CISC
+
+ .. only:: not gccint
+
+ which ``asm`` distinguishes. For example, an add instruction uses
+ two input operands and an output operand, but on most CISC
+
+ machines an add instruction really has only two operands, one of them an
+ input-output operand:
+
+ .. code-block::
+
+ addl #35,r12
+
+ Matching constraints are used in these circumstances.
+ More precisely, the two operands that match must include one input-only
+ operand and one output-only operand. Moreover, the digit must be a
+ smaller number than the number of the operand that uses it in the
+ constraint.
+
+ .. only:: gccint
+
+ For operands to match in a particular case usually means that they
+ are identical-looking RTL expressions. But in a few special cases
+ specific kinds of dissimilarity are allowed. For example, ``*x``
+ as an input operand will match ``*x++`` as an output operand.
+ For proper results in such cases, the output template should always
+ use the output-operand's number when printing the operand.
+
+ .. index:: load address instruction
+
+ .. index:: push address instruction
+
+ .. index:: address constraints
+
+ .. index:: p in constraint
+
+p
+ An operand that is a valid memory address is allowed. This is
+ for 'load address' and 'push address' instructions.
+
+ .. index:: address_operand
+
+ :samp:`p` in the constraint must be accompanied by ``address_operand``
+ as the predicate in the ``match_operand``. This predicate interprets
+ the mode specified in the ``match_operand`` as the mode of the memory
+ reference for which the address would be valid.
+
+ .. index:: other register constraints
+
+ .. index:: extensible constraints
+
+other-letters
+ Other letters can be defined in machine-dependent fashion to stand for
+ particular classes of registers or other arbitrary operand types.
+ :samp:`d`, :samp:`a` and :samp:`f` are defined on the 68000/68020 to stand
+ for data, address and floating point registers.
+
+.. only:: gccint
+
+ In order to have valid assembler code, each operand must satisfy
+ its constraint. But a failure to do so does not prevent the pattern
+ from applying to an insn. Instead, it directs the compiler to modify
+ the code so that the constraint will be satisfied. Usually this is
+ done by copying an operand into a register.
+
+ Contrast, therefore, the two instruction patterns that follow:
+
+ .. code-block:: c++
+
+ (define_insn ""
+ [(set (match_operand:SI 0 "general_operand" "=r")
+ (plus:SI (match_dup 0)
+ (match_operand:SI 1 "general_operand" "r")))]
+ ""
+ "...")
+
+ which has two operands, one of which must appear in two places, and
+
+ .. code-block:: c++
+
+ (define_insn ""
+ [(set (match_operand:SI 0 "general_operand" "=r")
+ (plus:SI (match_operand:SI 1 "general_operand" "0")
+ (match_operand:SI 2 "general_operand" "r")))]
+ ""
+ "...")
+
+ which has three operands, two of which are required by a constraint to be
+ identical. If we are considering an insn of the form
+
+ .. code-block:: c++
+
+ (insn n prev next
+ (set (reg:SI 3)
+ (plus:SI (reg:SI 6) (reg:SI 109)))
+ ...)
+
+ the first pattern would not apply at all, because this insn does not
+ contain two identical subexpressions in the right place. The pattern would
+ say, 'That does not look like an add instruction; try other patterns'.
+ The second pattern would say, 'Yes, that's an add instruction, but there
+ is something wrong with it'. It would direct the reload pass of the
+ compiler to generate additional insns to make the constraint true. The
+ results might look like this:
+
+ .. code-block:: c++
+
+ (insn n2 prev n
+ (set (reg:SI 3) (reg:SI 6))
+ ...)
+
+ (insn n n2 next
+ (set (reg:SI 3)
+ (plus:SI (reg:SI 3) (reg:SI 109)))
+ ...)
+
+ It is up to you to make sure that each operand, in each pattern, has
+ constraints that can handle any RTL expression that could be present for
+ that operand. (When multiple alternatives are in use, each pattern must,
+ for each possible combination of operand expressions, have at least one
+ alternative which can handle that combination of operands.) The
+ constraints don't need to *allow* any possible operand---when this is
+ the case, they do not constrain---but they must at least point the way to
+ reloading any possible operand so that it will fit.
+
+ * If the constraint accepts whatever operands the predicate permits,
+ there is no problem: reloading is never necessary for this operand.
+
+ For example, an operand whose constraints permit everything except
+ registers is safe provided its predicate rejects registers.
+
+ An operand whose predicate accepts only constant values is safe
+ provided its constraints include the letter :samp:`i`. If any possible
+ constant value is accepted, then nothing less than :samp:`i` will do;
+ if the predicate is more selective, then the constraints may also be
+ more selective.
+
+ * Any operand expression can be reloaded by copying it into a register.
+ So if an operand's constraints allow some kind of register, it is
+ certain to be safe. It need not permit all classes of registers; the
+ compiler knows how to copy a register into another register of the
+ proper class in order to make an instruction valid.
+
+ .. index:: nonoffsettable memory reference
+
+ .. index:: memory reference, nonoffsettable
+
+ * A nonoffsettable memory reference can be reloaded by copying the
+ address into a register. So if the constraint uses the letter
+ :samp:`o`, all memory references are taken care of.
+
+ * A constant operand can be reloaded by allocating space in memory to
+ hold it as preinitialized data. Then the memory reference can be used
+ in place of the constant. So if the constraint uses the letters
+ :samp:`o` or :samp:`m`, constant operands are not a problem.
+
+ * If the constraint permits a constant and a pseudo register used in an insn
+ was not allocated to a hard register and is equivalent to a constant,
+ the register will be replaced with the constant. If the predicate does
+ not permit a constant and the insn is re-recognized for some reason, the
+ compiler will crash. Thus the predicate must always recognize any
+ objects allowed by the constraint.
+
+ If the operand's predicate can recognize registers, but the constraint does
+ not permit them, it can make the compiler crash. When this operand happens
+ to be a register, the reload pass will be stymied, because it does not know
+ how to copy a register temporarily into memory.
+
+ If the predicate accepts a unary operator, the constraint applies to the
+ operand. For example, the MIPS processor at ISA level 3 supports an
+ instruction which adds two registers in ``SImode`` to produce a
+ ``DImode`` result, but only if the registers are correctly sign
+ extended. This predicate for the input operands accepts a
+ ``sign_extend`` of an ``SImode`` register. Write the constraint
+ to indicate the type of register that is required for the operand of the
+ ``sign_extend``.
+
+.. only:: not gccint
+
+ So the first alternative for the 68000's logical-or could be written as
+ ``"+m" (output) : "ir" (input)``. The second could be ``"+r"
+ (output): "irm" (input)``. However, the fact that two memory locations
+ cannot be used in a single instruction prevents simply using ``"+rm"
+ (output) : "irm" (input)``. Using multi-alternatives, this might be
+ written as ``"+m,r" (output) : "ir,irm" (input)``. This describes
+ all the available alternatives to the compiler, allowing it to choose
+ the most efficient one for the current conditions.
+
+ There is no way within the template to determine which alternative was
+ chosen. However you may be able to wrap your ``asm`` statements with
+ builtins such as ``__builtin_constant_p`` to achieve the desired results.
+
+.. _multi-alternative:
+
+Multiple Alternative Constraints
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: multiple alternative constraints
+
+Sometimes a single instruction has multiple alternative sets of possible
+operands. For example, on the 68000, a logical-or instruction can combine
+register or an immediate value into memory, or it can combine any kind of
+operand into a register; but it cannot combine one memory location into
+another.
+
+These constraints are represented as multiple alternatives. An alternative
+can be described by a series of letters for each operand. The overall
+constraint for an operand is made from the letters for this operand
+from the first alternative, a comma, the letters for this operand from
+the second alternative, a comma, and so on until the last alternative.
+All operands for a single instruction must have the same number of
+alternatives.
+
+.. only:: gccint
+
+ Here is how it is done for fullword logical-or on the 68000:
+
+ .. code-block:: c++
+
+ (define_insn "iorsi3"
+ [(set (match_operand:SI 0 "general_operand" "=m,d")
+ (ior:SI (match_operand:SI 1 "general_operand" "%0,0")
+ (match_operand:SI 2 "general_operand" "dKs,dmKs")))]
+ ...)
+
+ The first alternative has :samp:`m` (memory) for operand 0, :samp:`0` for
+ operand 1 (meaning it must match operand 0), and :samp:`dKs` for operand
+ 2. The second alternative has :samp:`d` (data register) for operand 0,
+ :samp:`0` for operand 1, and :samp:`dmKs` for operand 2. The :samp:`=` and
+ :samp:`%` in the constraints apply to all the alternatives; their
+ meaning is explained in the next section (see :ref:`class-preferences`).
+
+ If all the operands fit any one alternative, the instruction is valid.
+ Otherwise, for each alternative, the compiler counts how many instructions
+ must be added to copy the operands so that that alternative applies.
+ The alternative requiring the least copying is chosen. If two alternatives
+ need the same amount of copying, the one that comes first is chosen.
+ These choices can be altered with the :samp:`?` and :samp:`!` characters:
+
+ .. index:: ? in constraint
+
+ .. index:: question mark
+
+ ``?``
+ Disparage slightly the alternative that the :samp:`?` appears in,
+ as a choice when no alternative applies exactly. The compiler regards
+ this alternative as one unit more costly for each :samp:`?` that appears
+ in it.
+
+ .. index:: ! in constraint
+
+ .. index:: exclamation point
+
+ ``!``
+ Disparage severely the alternative that the :samp:`!` appears in.
+ This alternative can still be used if it fits without reloading,
+ but if reloading is needed, some other alternative will be used.
+
+ .. index:: ^ in constraint
+
+ .. index:: caret
+
+ ``^``
+ This constraint is analogous to :samp:`?` but it disparages slightly
+ the alternative only if the operand with the :samp:`^` needs a reload.
+
+ .. index:: $ in constraint
+
+ .. index:: dollar sign
+
+ ``$``
+ This constraint is analogous to :samp:`!` but it disparages severely
+ the alternative only if the operand with the :samp:`$` needs a reload.
+
+ When an insn pattern has multiple alternatives in its constraints, often
+ the appearance of the assembler code is determined mostly by which
+ alternative was matched. When this is so, the C code for writing the
+ assembler code can use the variable ``which_alternative``, which is
+ the ordinal number of the alternative that was actually satisfied (0 for
+ the first, 1 for the second alternative, etc.). See :ref:`output-statement`.
+
+.. _class-preferences:
+
+Register Class Preferences
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. only:: gccint
+
+ .. index:: class preference constraints
+
+ .. index:: register class preference constraints
+
+ .. index:: voting between constraint alternatives
+
+ The operand constraints have another function: they enable the compiler
+ to decide which kind of hardware register a pseudo register is best
+ allocated to. The compiler examines the constraints that apply to the
+ insns that use the pseudo register, looking for the machine-dependent
+ letters such as :samp:`d` and :samp:`a` that specify classes of registers.
+ The pseudo register is put in whichever class gets the most 'votes'.
+ The constraint letters :samp:`g` and :samp:`r` also vote: they vote in
+ favor of a general register. The machine description says which registers
+ are considered general.
+
+ Of course, on some machines all registers are equivalent, and no register
+ classes are defined. Then none of this complexity is relevant.
+
+.. _modifiers:
+
+Constraint Modifier Characters
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: modifiers in constraints
+
+.. index:: constraint modifier characters
+
+.. prevent bad page break with this line
+
+Here are constraint modifier characters.
+
+.. index:: = in constraint
+
+:samp:`=`
+ Means that this operand is written to by this instruction:
+ the previous value is discarded and replaced by new data.
+
+ .. index:: + in constraint
+
+:samp:`+`
+ Means that this operand is both read and written by the instruction.
+
+ When the compiler fixes up the operands to satisfy the constraints,
+ it needs to know which operands are read by the instruction and
+ which are written by it. :samp:`=` identifies an operand which is only
+ written; :samp:`+` identifies an operand that is both read and written; all
+ other operands are assumed to only be read.
+
+ If you specify :samp:`=` or :samp:`+` in a constraint, you put it in the
+ first character of the constraint string.
+
+ .. index:: & in constraint
+
+ .. index:: earlyclobber operand
+
+:samp:`&`
+ Means (in a particular alternative) that this operand is an
+ :dfn:`earlyclobber` operand, which is written before the instruction is
+ finished using the input operands. Therefore, this operand may not lie
+ in a register that is read by the instruction or as part of any memory
+ address.
+
+ :samp:`&` applies only to the alternative in which it is written. In
+ constraints with multiple alternatives, sometimes one alternative
+ requires :samp:`&` while others do not. See, for example, the
+ :samp:`movdf` insn of the 68000.
+
+ An operand which is read by the instruction can be tied to an earlyclobber
+ operand if its only use as an input occurs before the early result is
+ written. Adding alternatives of this form often allows GCC to produce
+ better code when only some of the read operands can be affected by the
+ earlyclobber. See, for example, the :samp:`mulsi3` insn of the ARM.
+
+ Furthermore, if the :dfn:`earlyclobber` operand is also a read/write
+ operand, then that operand is written only after it's used.
+
+ :samp:`&` does not obviate the need to write :samp:`=` or :samp:`+`. As
+ :dfn:`earlyclobber` operands are always written, a read-only
+ :dfn:`earlyclobber` operand is ill-formed and will be rejected by the
+ compiler.
+
+ .. index:: % in constraint
+
+:samp:`%`
+ Declares the instruction to be commutative for this operand and the
+ following operand. This means that the compiler may interchange the
+ two operands if that is the cheapest way to make all operands fit the
+ constraints. :samp:`%` applies to all alternatives and must appear as
+ the first character in the constraint. Only read-only operands can use
+ :samp:`%`.
+
+ .. only:: gccint
+
+ This is often used in patterns for addition instructions
+ that really have only two operands: the result must go in one of the
+ arguments. Here for example, is how the 68000 halfword-add
+ instruction is defined:
+
+ .. code-block:: c++
+
+ (define_insn "addhi3"
+ [(set (match_operand:HI 0 "general_operand" "=m,r")
+ (plus:HI (match_operand:HI 1 "general_operand" "%0,0")
+ (match_operand:HI 2 "general_operand" "di,g")))]
+ ...)
+
+ GCC can only handle one commutative pair in an asm; if you use more,
+ the compiler may fail. Note that you need not use the modifier if
+ the two alternatives are strictly identical; this would only waste
+ time in the reload pass.
+
+ .. only:: gccint
+
+ The modifier is not operational after
+ register allocation, so the result of ``define_peephole2``
+ and ``define_split`` s performed after reload cannot rely on
+ :samp:`%` to make the intended insn match.
+
+ .. index:: # in constraint
+
+ :samp:`#`
+ Says that all following characters, up to the next comma, are to be
+ ignored as a constraint. They are significant only for choosing
+ register preferences.
+
+ .. index:: * in constraint
+
+ :samp:`*`
+ Says that the following character should be ignored when choosing
+ register preferences. :samp:`*` has no effect on the meaning of the
+ constraint as a constraint, and no effect on reloading. For LRA
+ :samp:`*` additionally disparages slightly the alternative if the
+ following character matches the operand.
+
+ Here is an example: the 68000 has an instruction to sign-extend a
+ halfword in a data register, and can also sign-extend a value by
+ copying it into an address register. While either kind of register is
+ acceptable, the constraints on an address-register destination are
+ less strict, so it is best if register allocation makes an address
+ register its goal. Therefore, :samp:`*` is used so that the :samp:`d`
+ constraint letter (for data register) is ignored when computing
+ register preferences.
+
+ .. code-block:: c++
+
+ (define_insn "extendhisi2"
+ [(set (match_operand:SI 0 "general_operand" "=*d,a")
+ (sign_extend:SI
+ (match_operand:HI 1 "general_operand" "0,g")))]
+ ...)
+
+ .. _machine-constraints:
+
+Constraints for Particular Machines
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: machine specific constraints
+
+.. index:: constraints, machine specific
+
+Whenever possible, you should use the general-purpose constraint letters
+in ``asm`` arguments, since they will convey meaning more readily to
+people reading your code. Failing that, use the constraint letters
+that usually have very similar meanings across architectures. The most
+commonly used constraints are :samp:`m` and :samp:`r` (for memory and
+general-purpose registers respectively; see :ref:`simple-constraints`), and
+:samp:`I`, usually the letter indicating the most common
+immediate-constant format.
+
+Each architecture defines additional constraints. These constraints
+are used by the compiler itself for instruction generation, as well as
+for ``asm`` statements; therefore, some of the constraints are not
+particularly useful for ``asm``. Here is a summary of some of the
+machine-dependent constraints available on some particular machines;
+it includes both constraints that are useful for ``asm`` and
+constraints that aren't. The compiler source file mentioned in the
+table heading for each architecture is the definitive reference for
+the meanings of that architecture's constraints.
+
+.. Please keep this table alphabetized by target!
+
+AArch64 family---:samp:`{config/aarch64/constraints.md}`
+
+ ``k``
+ The stack pointer register ( ``SP`` )
+
+ ``w``
+ Floating point register, Advanced SIMD vector register or SVE vector register
+
+ ``x``
+ Like ``w``, but restricted to registers 0 to 15 inclusive.
+
+ ``y``
+ Like ``w``, but restricted to registers 0 to 7 inclusive.
+
+ ``Upl``
+ One of the low eight SVE predicate registers ( ``P0`` to ``P7`` )
+
+ ``Upa``
+ Any of the SVE predicate registers ( ``P0`` to ``P15`` )
+
+ ``I``
+ Integer constant that is valid as an immediate operand in an ``ADD``
+ instruction
+
+ ``J``
+ Integer constant that is valid as an immediate operand in a ``SUB``
+ instruction (once negated)
+
+ ``K``
+ Integer constant that can be used with a 32-bit logical instruction
+
+ ``L``
+ Integer constant that can be used with a 64-bit logical instruction
+
+ ``M``
+ Integer constant that is valid as an immediate operand in a 32-bit ``MOV``
+ pseudo instruction. The ``MOV`` may be assembled to one of several different
+ machine instructions depending on the value
+
+ ``N``
+ Integer constant that is valid as an immediate operand in a 64-bit ``MOV``
+ pseudo instruction
+
+ ``S``
+ An absolute symbolic address or a label reference
+
+ ``Y``
+ Floating point constant zero
+
+ ``Z``
+ Integer constant zero
+
+ ``Ush``
+ The high part (bits 12 and upwards) of the pc-relative address of a symbol
+ within 4GB of the instruction
+
+ ``Q``
+ A memory address which uses a single base register with no offset
+
+ ``Ump``
+ A memory address suitable for a load/store pair instruction in SI, DI, SF and
+ DF modes
+
+AMD GCN ---:samp:`{config/gcn/constraints.md}`
+
+ ``I``
+ Immediate integer in the range -16 to 64
+
+ ``J``
+ Immediate 16-bit signed integer
+
+ ``Kf``
+ Immediate constant -1
+
+ ``L``
+ Immediate 15-bit unsigned integer
+
+ ``A``
+ Immediate constant that can be inlined in an instruction encoding: integer
+ -16..64, or float 0.0, +/-0.5, +/-1.0, +/-2.0,
+ +/-4.0, 1.0/(2.0\*PI)
+
+ ``B``
+ Immediate 32-bit signed integer that can be attached to an instruction encoding
+
+ ``C``
+ Immediate 32-bit integer in range -16..4294967295 (i.e. 32-bit unsigned
+ integer or :samp:`A` constraint)
+
+ ``DA``
+ Immediate 64-bit constant that can be split into two :samp:`A` constants
+
+ ``DB``
+ Immediate 64-bit constant that can be split into two :samp:`B` constants
+
+ ``U``
+ Any ``unspec``
+
+ ``Y``
+ Any ``symbol_ref`` or ``label_ref``
+
+ ``v``
+ VGPR register
+
+ ``Sg``
+ SGPR register
+
+ ``SD``
+ SGPR registers valid for instruction destinations, including VCC, M0 and EXEC
+
+ ``SS``
+ SGPR registers valid for instruction sources, including VCC, M0, EXEC and SCC
+
+ ``Sm``
+ SGPR registers valid as a source for scalar memory instructions (excludes M0
+ and EXEC)
+
+ ``Sv``
+ SGPR registers valid as a source or destination for vector instructions
+ (excludes EXEC)
+
+ ``ca``
+ All condition registers: SCC, VCCZ, EXECZ
+
+ ``cs``
+ Scalar condition register: SCC
+
+ ``cV``
+ Vector condition register: VCC, VCC_LO, VCC_HI
+
+ ``e``
+ EXEC register (EXEC_LO and EXEC_HI)
+
+ ``RB``
+ Memory operand with address space suitable for ``buffer_*`` instructions
+
+ ``RF``
+ Memory operand with address space suitable for ``flat_*`` instructions
+
+ ``RS``
+ Memory operand with address space suitable for ``s_*`` instructions
+
+ ``RL``
+ Memory operand with address space suitable for ``ds_*`` LDS instructions
+
+ ``RG``
+ Memory operand with address space suitable for ``ds_*`` GDS instructions
+
+ ``RD``
+ Memory operand with address space suitable for any ``ds_*`` instructions
+
+ ``RM``
+ Memory operand with address space suitable for ``global_*`` instructions
+
+ARC ---:samp:`{config/arc/constraints.md}`
+
+ ``q``
+ Registers usable in ARCompact 16-bit instructions: ``r0`` - ``r3``,
+ ``r12`` - ``r15``. This constraint can only match when the :option:`-mq`
+ option is in effect.
+
+ ``e``
+ Registers usable as base-regs of memory addresses in ARCompact 16-bit memory
+ instructions: ``r0`` - ``r3``, ``r12`` - ``r15``, ``sp``.
+ This constraint can only match when the :option:`-mq`
+ option is in effect.
+
+ ``D``
+ ARC FPX (dpfp) 64-bit registers. ``D0``, ``D1``.
+
+ ``I``
+ A signed 12-bit integer constant.
+
+ ``Cal``
+ constant for arithmetic/logical operations. This might be any constant
+ that can be put into a long immediate by the assmbler or linker without
+ involving a PIC relocation.
+
+ ``K``
+ A 3-bit unsigned integer constant.
+
+ ``L``
+ A 6-bit unsigned integer constant.
+
+ ``CnL``
+ One's complement of a 6-bit unsigned integer constant.
+
+ ``CmL``
+ Two's complement of a 6-bit unsigned integer constant.
+
+ ``M``
+ A 5-bit unsigned integer constant.
+
+ ``O``
+ A 7-bit unsigned integer constant.
+
+ ``P``
+ A 8-bit unsigned integer constant.
+
+ ``H``
+ Any const_double value.
+
+ARM family---:samp:`{config/arm/constraints.md}`
+
+ ``h``
+ In Thumb state, the core registers ``r8`` - ``r15``.
+
+ ``k``
+ The stack pointer register.
+
+ ``l``
+ In Thumb State the core registers ``r0`` - ``r7``. In ARM state this
+ is an alias for the ``r`` constraint.
+
+ ``t``
+ VFP floating-point registers ``s0`` - ``s31``. Used for 32 bit values.
+
+ ``w``
+ VFP floating-point registers ``d0`` - ``d31`` and the appropriate
+ subset ``d0`` - ``d15`` based on command line options.
+ Used for 64 bit values only. Not valid for Thumb1.
+
+ ``y``
+ The iWMMX co-processor registers.
+
+ ``z``
+ The iWMMX GR registers.
+
+ ``G``
+ The floating-point constant 0.0
+
+ ``I``
+ Integer that is valid as an immediate operand in a data processing
+ instruction. That is, an integer in the range 0 to 255 rotated by a
+ multiple of 2
+
+ ``J``
+ Integer in the range -4095 to 4095
+
+ ``K``
+ Integer that satisfies constraint :samp:`I` when inverted (ones complement)
+
+ ``L``
+ Integer that satisfies constraint :samp:`I` when negated (twos complement)
+
+ ``M``
+ Integer in the range 0 to 32
+
+ ``Q``
+ A memory reference where the exact address is in a single register
+ (':samp:`m`' is preferable for ``asm`` statements)
+
+ ``R``
+ An item in the constant pool
+
+ ``S``
+ A symbol in the text segment of the current file
+
+ ``Uv``
+ A memory reference suitable for VFP load/store insns (reg+constant offset)
+
+ ``Uy``
+ A memory reference suitable for iWMMXt load/store instructions.
+
+ ``Uq``
+ A memory reference suitable for the ARMv4 ldrsb instruction.
+
+AVR family---:samp:`{config/avr/constraints.md}`
+
+ ``l``
+ Registers from r0 to r15
+
+ ``a``
+ Registers from r16 to r23
+
+ ``d``
+ Registers from r16 to r31
+
+ ``w``
+ Registers from r24 to r31. These registers can be used in :samp:`adiw` command
+
+ ``e``
+ Pointer register (r26--r31)
+
+ ``b``
+ Base pointer register (r28--r31)
+
+ ``q``
+ Stack pointer register (SPH:SPL)
+
+ ``t``
+ Temporary register r0
+
+ ``x``
+ Register pair X (r27:r26)
+
+ ``y``
+ Register pair Y (r29:r28)
+
+ ``z``
+ Register pair Z (r31:r30)
+
+ ``I``
+ Constant greater than -1, less than 64
+
+ ``J``
+ Constant greater than -64, less than 1
+
+ ``K``
+ Constant integer 2
+
+ ``L``
+ Constant integer 0
+
+ ``M``
+ Constant that fits in 8 bits
+
+ ``N``
+ Constant integer -1
+
+ ``O``
+ Constant integer 8, 16, or 24
+
+ ``P``
+ Constant integer 1
+
+ ``G``
+ A floating point constant 0.0
+
+ ``Q``
+ A memory address based on Y or Z pointer with displacement.
+
+Blackfin family---:samp:`{config/bfin/constraints.md}`
+
+ ``a``
+ P register
+
+ ``d``
+ D register
+
+ ``z``
+ A call clobbered P register.
+
+ :samp:`q{n}`
+ A single register. If :samp:`{n}` is in the range 0 to 7, the corresponding D
+ register. If it is ``A``, then the register P0.
+
+ ``D``
+ Even-numbered D register
+
+ ``W``
+ Odd-numbered D register
+
+ ``e``
+ Accumulator register.
+
+ ``A``
+ Even-numbered accumulator register.
+
+ ``B``
+ Odd-numbered accumulator register.
+
+ ``b``
+ I register
+
+ ``v``
+ B register
+
+ ``f``
+ M register
+
+ ``c``
+ Registers used for circular buffering, i.e. I, B, or L registers.
+
+ ``C``
+ The CC register.
+
+ ``t``
+ LT0 or LT1.
+
+ ``k``
+ LC0 or LC1.
+
+ ``u``
+ LB0 or LB1.
+
+ ``x``
+ Any D, P, B, M, I or L register.
+
+ ``y``
+ Additional registers typically used only in prologues and epilogues: RETS,
+ RETN, RETI, RETX, RETE, ASTAT, SEQSTAT and USP.
+
+ ``w``
+ Any register except accumulators or CC.
+
+ ``Ksh``
+ Signed 16 bit integer (in the range -32768 to 32767)
+
+ ``Kuh``
+ Unsigned 16 bit integer (in the range 0 to 65535)
+
+ ``Ks7``
+ Signed 7 bit integer (in the range -64 to 63)
+
+ ``Ku7``
+ Unsigned 7 bit integer (in the range 0 to 127)
+
+ ``Ku5``
+ Unsigned 5 bit integer (in the range 0 to 31)
+
+ ``Ks4``
+ Signed 4 bit integer (in the range -8 to 7)
+
+ ``Ks3``
+ Signed 3 bit integer (in the range -3 to 4)
+
+ ``Ku3``
+ Unsigned 3 bit integer (in the range 0 to 7)
+
+ :samp:`P{n}`
+ Constant :samp:`{n}`, where :samp:`{n}` is a single-digit constant in the range 0 to 4.
+
+ ``PA``
+ An integer equal to one of the MACFLAG_XXX constants that is suitable for
+ use with either accumulator.
+
+ ``PB``
+ An integer equal to one of the MACFLAG_XXX constants that is suitable for
+ use only with accumulator A1.
+
+ ``M1``
+ Constant 255.
+
+ ``M2``
+ Constant 65535.
+
+ ``J``
+ An integer constant with exactly a single bit set.
+
+ ``L``
+ An integer constant with all bits set except exactly one.
+
+ ``H``
+
+ ``Q``
+ Any SYMBOL_REF.
+
+CR16 Architecture---:samp:`{config/cr16/cr16.h}`
+
+ ``b``
+ Registers from r0 to r14 (registers without stack pointer)
+
+ ``t``
+ Register from r0 to r11 (all 16-bit registers)
+
+ ``p``
+ Register from r12 to r15 (all 32-bit registers)
+
+ ``I``
+ Signed constant that fits in 4 bits
+
+ ``J``
+ Signed constant that fits in 5 bits
+
+ ``K``
+ Signed constant that fits in 6 bits
+
+ ``L``
+ Unsigned constant that fits in 4 bits
+
+ ``M``
+ Signed constant that fits in 32 bits
+
+ ``N``
+ Check for 64 bits wide constants for add/sub instructions
+
+ ``G``
+ Floating point constant that is legal for store immediate
+
+C-SKY---:samp:`{config/csky/constraints.md}`
+
+ ``a``
+ The mini registers r0 - r7.
+
+ ``b``
+ The low registers r0 - r15.
+
+ ``c``
+ C register.
+
+ ``y``
+ HI and LO registers.
+
+ ``l``
+ LO register.
+
+ ``h``
+ HI register.
+
+ ``v``
+ Vector registers.
+
+ ``z``
+ Stack pointer register (SP).
+
+ ``Q``
+ A memory address which uses a base register with a short offset
+ or with a index register with its scale.
+
+ ``W``
+ A memory address which uses a base register with a index register
+ with its scale.
+
+ .. only:: gccint
+
+ The C-SKY back end supports a large set of additional constraints
+ that are only useful for instruction selection or splitting rather
+ than inline asm, such as constraints representing constant integer
+ ranges accepted by particular instruction encodings.
+ Refer to the source code for details.
+
+Epiphany---:samp:`{config/epiphany/constraints.md}`
+
+ ``U16``
+ An unsigned 16-bit constant.
+
+ ``K``
+ An unsigned 5-bit constant.
+
+ ``L``
+ A signed 11-bit constant.
+
+ ``Cm1``
+ A signed 11-bit constant added to -1.
+ Can only match when the :option:`-m1reg-`:samp:`{reg}` option is active.
+
+ ``Cl1``
+ Left-shift of -1, i.e., a bit mask with a block of leading ones, the rest
+ being a block of trailing zeroes.
+ Can only match when the :option:`-m1reg-`:samp:`{reg}` option is active.
+
+ ``Cr1``
+ Right-shift of -1, i.e., a bit mask with a trailing block of ones, the
+ rest being zeroes. Or to put it another way, one less than a power of two.
+ Can only match when the :option:`-m1reg-`:samp:`{reg}` option is active.
+
+ ``Cal``
+ Constant for arithmetic/logical operations.
+ This is like ``i``, except that for position independent code,
+ no symbols / expressions needing relocations are allowed.
+
+ ``Csy``
+ Symbolic constant for call/jump instruction.
+
+ ``Rcs``
+ The register class usable in short insns. This is a register class
+ constraint, and can thus drive register allocation.
+ This constraint won't match unless :option:`-mprefer-short-insn-regs` is
+ in effect.
+
+ ``Rsc``
+ The the register class of registers that can be used to hold a
+ sibcall call address. I.e., a caller-saved register.
+
+ ``Rct``
+ Core control register class.
+
+ ``Rgs``
+ The register group usable in short insns.
+ This constraint does not use a register class, so that it only
+ passively matches suitable registers, and doesn't drive register allocation.
+
+ .. only:: gccint
+
+ ``Car``
+ Constant suitable for the addsi3_r pattern. This is a valid offset
+ For byte, halfword, or word addressing.
+
+ ``Rra``
+ Matches the return address if it can be replaced with the link register.
+
+ ``Rcc``
+ Matches the integer condition code register.
+
+ ``Sra``
+ Matches the return address if it is in a stack slot.
+
+ ``Cfm``
+ Matches control register values to switch fp mode, which are encapsulated in
+ ``UNSPEC_FP_MODE``.
+
+FRV---:samp:`{config/frv/frv.h}`
+
+ ``a``
+ Register in the class ``ACC_REGS`` ( ``acc0`` to ``acc7`` ).
+
+ ``b``
+ Register in the class ``EVEN_ACC_REGS`` ( ``acc0`` to ``acc7`` ).
+
+ ``c``
+ Register in the class ``CC_REGS`` ( ``fcc0`` to ``fcc3`` and
+ ``icc0`` to ``icc3`` ).
+
+ ``d``
+ Register in the class ``GPR_REGS`` ( ``gr0`` to ``gr63`` ).
+
+ ``e``
+ Register in the class ``EVEN_REGS`` ( ``gr0`` to ``gr63`` ).
+ Odd registers are excluded not in the class but through the use of a machine
+ mode larger than 4 bytes.
+
+ ``f``
+ Register in the class ``FPR_REGS`` ( ``fr0`` to ``fr63`` ).
+
+ ``h``
+ Register in the class ``FEVEN_REGS`` ( ``fr0`` to ``fr63`` ).
+ Odd registers are excluded not in the class but through the use of a machine
+ mode larger than 4 bytes.
+
+ ``l``
+ Register in the class ``LR_REG`` (the ``lr`` register).
+
+ ``q``
+ Register in the class ``QUAD_REGS`` ( ``gr2`` to ``gr63`` ).
+ Register numbers not divisible by 4 are excluded not in the class but through
+ the use of a machine mode larger than 8 bytes.
+
+ ``t``
+ Register in the class ``ICC_REGS`` ( ``icc0`` to ``icc3`` ).
+
+ ``u``
+ Register in the class ``FCC_REGS`` ( ``fcc0`` to ``fcc3`` ).
+
+ ``v``
+ Register in the class ``ICR_REGS`` ( ``cc4`` to ``cc7`` ).
+
+ ``w``
+ Register in the class ``FCR_REGS`` ( ``cc0`` to ``cc3`` ).
+
+ ``x``
+ Register in the class ``QUAD_FPR_REGS`` ( ``fr0`` to ``fr63`` ).
+ Register numbers not divisible by 4 are excluded not in the class but through
+ the use of a machine mode larger than 8 bytes.
+
+ ``z``
+ Register in the class ``SPR_REGS`` ( ``lcr`` and ``lr`` ).
+
+ ``A``
+ Register in the class ``QUAD_ACC_REGS`` ( ``acc0`` to ``acc7`` ).
+
+ ``B``
+ Register in the class ``ACCG_REGS`` ( ``accg0`` to ``accg7`` ).
+
+ ``C``
+ Register in the class ``CR_REGS`` ( ``cc0`` to ``cc7`` ).
+
+ ``G``
+ Floating point constant zero
+
+ ``I``
+ 6-bit signed integer constant
+
+ ``J``
+ 10-bit signed integer constant
+
+ ``L``
+ 16-bit signed integer constant
+
+ ``M``
+ 16-bit unsigned integer constant
+
+ ``N``
+ 12-bit signed integer constant that is negative---i.e. in the
+ range of -2048 to -1
+
+ ``O``
+ Constant zero
+
+ ``P``
+ 12-bit signed integer constant that is greater than zero---i.e. in the
+ range of 1 to 2047.
+
+FT32---:samp:`{config/ft32/constraints.md}`
+
+ ``A``
+ An absolute address
+
+ ``B``
+ An offset address
+
+ ``W``
+ A register indirect memory operand
+
+ ``e``
+ An offset address.
+
+ ``f``
+ An offset address.
+
+ ``O``
+ The constant zero or one
+
+ ``I``
+ A 16-bit signed constant (-32768 ... 32767)
+
+ ``w``
+ A bitfield mask suitable for bext or bins
+
+ ``x``
+ An inverted bitfield mask suitable for bext or bins
+
+ ``L``
+ A 16-bit unsigned constant, multiple of 4 (0 ... 65532)
+
+ ``S``
+ A 20-bit signed constant (-524288 ... 524287)
+
+ ``b``
+ A constant for a bitfield width (1 ... 16)
+
+ ``KA``
+ A 10-bit signed constant (-512 ... 511)
+
+Hewlett-Packard PA-RISC---:samp:`{config/pa/pa.h}`
+
+ ``a``
+ General register 1
+
+ ``f``
+ Floating point register
+
+ ``q``
+ Shift amount register
+
+ ``x``
+ Floating point register (deprecated)
+
+ ``y``
+ Upper floating point register (32-bit), floating point register (64-bit)
+
+ ``Z``
+ Any register
+
+ ``I``
+ Signed 11-bit integer constant
+
+ ``J``
+ Signed 14-bit integer constant
+
+ ``K``
+ Integer constant that can be deposited with a ``zdepi`` instruction
+
+ ``L``
+ Signed 5-bit integer constant
+
+ ``M``
+ Integer constant 0
+
+ ``N``
+ Integer constant that can be loaded with a ``ldil`` instruction
+
+ ``O``
+ Integer constant whose value plus one is a power of 2
+
+ ``P``
+ Integer constant that can be used for ``and`` operations in ``depi``
+ and ``extru`` instructions
+
+ ``S``
+ Integer constant 31
+
+ ``U``
+ Integer constant 63
+
+ ``G``
+ Floating-point constant 0.0
+
+ ``A``
+ A ``lo_sum`` data-linkage-table memory operand
+
+ ``Q``
+ A memory operand that can be used as the destination operand of an
+ integer store instruction
+
+ ``R``
+ A scaled or unscaled indexed memory operand
+
+ ``T``
+ A memory operand for floating-point loads and stores
+
+ ``W``
+ A register indirect memory operand
+
+Intel IA-64---:samp:`{config/ia64/ia64.h}`
+
+ ``a``
+ General register ``r0`` to ``r3`` for ``addl`` instruction
+
+ ``b``
+ Branch register
+
+ ``c``
+ Predicate register (:samp:`c` as in 'conditional')
+
+ ``d``
+ Application register residing in M-unit
+
+ ``e``
+ Application register residing in I-unit
+
+ ``f``
+ Floating-point register
+
+ ``m``
+ Memory operand. If used together with :samp:`<` or :samp:`>`,
+ the operand can have postincrement and postdecrement which
+ require printing with :samp:`%Pn` on IA-64.
+
+ ``G``
+ Floating-point constant 0.0 or 1.0
+
+ ``I``
+ 14-bit signed integer constant
+
+ ``J``
+ 22-bit signed integer constant
+
+ ``K``
+ 8-bit signed integer constant for logical instructions
+
+ ``L``
+ 8-bit adjusted signed integer constant for compare pseudo-ops
+
+ ``M``
+ 6-bit unsigned integer constant for shift counts
+
+ ``N``
+ 9-bit signed integer constant for load and store postincrements
+
+ ``O``
+ The constant zero
+
+ ``P``
+ 0 or -1 for ``dep`` instruction
+
+ ``Q``
+ Non-volatile memory for floating-point loads and stores
+
+ ``R``
+ Integer constant in the range 1 to 4 for ``shladd`` instruction
+
+ ``S``
+ Memory operand except postincrement and postdecrement. This is
+ now roughly the same as :samp:`m` when not used together with :samp:`<`
+ or :samp:`>`.
+
+M32C---:samp:`{config/m32c/m32c.c}`
+
+ ``Rsp`` ``Rfb`` ``Rsb``
+ :samp:`$sp`, :samp:`$fb`, :samp:`$sb`.
+
+ ``Rcr``
+ Any control register, when they're 16 bits wide (nothing if control
+ registers are 24 bits wide)
+
+ ``Rcl``
+ Any control register, when they're 24 bits wide.
+
+ ``R0w`` ``R1w`` ``R2w`` ``R3w``
+ $r0, $r1, $r2, $r3.
+
+ ``R02``
+ $r0 or $r2, or $r2r0 for 32 bit values.
+
+ ``R13``
+ $r1 or $r3, or $r3r1 for 32 bit values.
+
+ ``Rdi``
+ A register that can hold a 64 bit value.
+
+ ``Rhl``
+ $r0 or $r1 (registers with addressable high/low bytes)
+
+ ``R23``
+ $r2 or $r3
+
+ ``Raa``
+ Address registers
+
+ ``Raw``
+ Address registers when they're 16 bits wide.
+
+ ``Ral``
+ Address registers when they're 24 bits wide.
+
+ ``Rqi``
+ Registers that can hold QI values.
+
+ ``Rad``
+ Registers that can be used with displacements ($a0, $a1, $sb).
+
+ ``Rsi``
+ Registers that can hold 32 bit values.
+
+ ``Rhi``
+ Registers that can hold 16 bit values.
+
+ ``Rhc``
+ Registers chat can hold 16 bit values, including all control
+ registers.
+
+ ``Rra``
+ $r0 through R1, plus $a0 and $a1.
+
+ ``Rfl``
+ The flags register.
+
+ ``Rmm``
+ The memory-based pseudo-registers $mem0 through $mem15.
+
+ ``Rpi``
+ Registers that can hold pointers (16 bit registers for r8c, m16c; 24
+ bit registers for m32cm, m32c).
+
+ ``Rpa``
+ Matches multiple registers in a PARALLEL to form a larger register.
+ Used to match function return values.
+
+ ``Is3``
+ -8 ... 7
+
+ ``IS1``
+ -128 ... 127
+
+ ``IS2``
+ -32768 ... 32767
+
+ ``IU2``
+ 0 ... 65535
+
+ ``In4``
+ -8 ... -1 or 1 ... 8
+
+ ``In5``
+ -16 ... -1 or 1 ... 16
+
+ ``In6``
+ -32 ... -1 or 1 ... 32
+
+ ``IM2``
+ -65536 ... -1
+
+ ``Ilb``
+ An 8 bit value with exactly one bit set.
+
+ ``Ilw``
+ A 16 bit value with exactly one bit set.
+
+ ``Sd``
+ The common src/dest memory addressing modes.
+
+ ``Sa``
+ Memory addressed using $a0 or $a1.
+
+ ``Si``
+ Memory addressed with immediate addresses.
+
+ ``Ss``
+ Memory addressed using the stack pointer ($sp).
+
+ ``Sf``
+ Memory addressed using the frame base register ($fb).
+
+ ``Ss``
+ Memory addressed using the small base register ($sb).
+
+ ``S1``
+ $r1h
+
+MicroBlaze---:samp:`{config/microblaze/constraints.md}`
+
+ ``d``
+ A general register ( ``r0`` to ``r31`` ).
+
+ ``z``
+ A status register ( ``rmsr``, ``$fcc1`` to ``$fcc7`` ).
+
+MIPS---:samp:`{config/mips/constraints.md}`
+
+ ``d``
+ A general-purpose register. This is equivalent to ``r`` unless
+ generating MIPS16 code, in which case the MIPS16 register set is used.
+
+ ``f``
+ A floating-point register (if available).
+
+ ``h``
+ Formerly the ``hi`` register. This constraint is no longer supported.
+
+ ``l``
+ The ``lo`` register. Use this register to store values that are
+ no bigger than a word.
+
+ ``x``
+ The concatenated ``hi`` and ``lo`` registers. Use this register
+ to store doubleword values.
+
+ ``c``
+ A register suitable for use in an indirect jump. This will always be
+ ``$25`` for :option:`-mabicalls`.
+
+ ``v``
+ Register ``$3``. Do not use this constraint in new code;
+ it is retained only for compatibility with glibc.
+
+ ``y``
+ Equivalent to ``r`` ; retained for backwards compatibility.
+
+ ``z``
+ A floating-point condition code register.
+
+ ``I``
+ A signed 16-bit constant (for arithmetic instructions).
+
+ ``J``
+ Integer zero.
+
+ ``K``
+ An unsigned 16-bit constant (for logic instructions).
+
+ ``L``
+ A signed 32-bit constant in which the lower 16 bits are zero.
+ Such constants can be loaded using ``lui``.
+
+ ``M``
+ A constant that cannot be loaded using ``lui``, ``addiu``
+ or ``ori``.
+
+ ``N``
+ A constant in the range -65535 to -1 (inclusive).
+
+ ``O``
+ A signed 15-bit constant.
+
+ ``P``
+ A constant in the range 1 to 65535 (inclusive).
+
+ ``G``
+ Floating-point zero.
+
+ ``R``
+ An address that can be used in a non-macro load or store.
+
+ ``ZC``
+ A memory operand whose address is formed by a base register and offset
+ that is suitable for use in instructions with the same addressing mode
+ as ``ll`` and ``sc``.
+
+ ``ZD``
+ An address suitable for a ``prefetch`` instruction, or for any other
+ instruction with the same addressing mode as ``prefetch``.
+
+Motorola 680x0---:samp:`{config/m68k/constraints.md}`
+
+ ``a``
+ Address register
+
+ ``d``
+ Data register
+
+ ``f``
+ 68881 floating-point register, if available
+
+ ``I``
+ Integer in the range 1 to 8
+
+ ``J``
+ 16-bit signed number
+
+ ``K``
+ Signed number whose magnitude is greater than 0x80
+
+ ``L``
+ Integer in the range -8 to -1
+
+ ``M``
+ Signed number whose magnitude is greater than 0x100
+
+ ``N``
+ Range 24 to 31, rotatert:SI 8 to 1 expressed as rotate
+
+ ``O``
+ 16 (for rotate using swap)
+
+ ``P``
+ Range 8 to 15, rotatert:HI 8 to 1 expressed as rotate
+
+ ``R``
+ Numbers that mov3q can handle
+
+ ``G``
+ Floating point constant that is not a 68881 constant
+
+ ``S``
+ Operands that satisfy 'm' when -mpcrel is in effect
+
+ ``T``
+ Operands that satisfy 's' when -mpcrel is not in effect
+
+ ``Q``
+ Address register indirect addressing mode
+
+ ``U``
+ Register offset addressing
+
+ ``W``
+ const_call_operand
+
+ ``Cs``
+ symbol_ref or const
+
+ ``Ci``
+ const_int
+
+ ``C0``
+ const_int 0
+
+ ``Cj``
+ Range of signed numbers that don't fit in 16 bits
+
+ ``Cmvq``
+ Integers valid for mvq
+
+ ``Capsw``
+ Integers valid for a moveq followed by a swap
+
+ ``Cmvz``
+ Integers valid for mvz
+
+ ``Cmvs``
+ Integers valid for mvs
+
+ ``Ap``
+ push_operand
+
+ ``Ac``
+ Non-register operands allowed in clr
+
+Moxie---:samp:`{config/moxie/constraints.md}`
+
+ ``A``
+ An absolute address
+
+ ``B``
+ An offset address
+
+ ``W``
+ A register indirect memory operand
+
+ ``I``
+ A constant in the range of 0 to 255.
+
+ ``N``
+ A constant in the range of 0 to -255.
+
+:samp:`MSP430--{config/msp430/constraints.md}`
+
+ ``R12``
+ Register R12.
+
+ ``R13``
+ Register R13.
+
+ ``K``
+ Integer constant 1.
+
+ ``L``
+ Integer constant -1^20..1^19.
+
+ ``M``
+ Integer constant 1-4.
+
+ ``Ya``
+ Memory references which do not require an extended MOVX instruction.
+
+ ``Yl``
+ Memory reference, labels only.
+
+ ``Ys``
+ Memory reference, stack only.
+
+NDS32---:samp:`{config/nds32/constraints.md}`
+
+ ``w``
+ LOW register class $r0 to $r7 constraint for V3/V3M ISA.
+
+ ``l``
+ LOW register class $r0 to $r7.
+
+ ``d``
+ MIDDLE register class $r0 to $r11, $r16 to $r19.
+
+ ``h``
+ HIGH register class $r12 to $r14, $r20 to $r31.
+
+ ``t``
+ Temporary assist register $ta (i.e. $r15).
+
+ ``k``
+ Stack register $sp.
+
+ ``Iu03``
+ Unsigned immediate 3-bit value.
+
+ ``In03``
+ Negative immediate 3-bit value in the range of -7--0.
+
+ ``Iu04``
+ Unsigned immediate 4-bit value.
+
+ ``Is05``
+ Signed immediate 5-bit value.
+
+ ``Iu05``
+ Unsigned immediate 5-bit value.
+
+ ``In05``
+ Negative immediate 5-bit value in the range of -31--0.
+
+ ``Ip05``
+ Unsigned immediate 5-bit value for movpi45 instruction with range 16--47.
+
+ ``Iu06``
+ Unsigned immediate 6-bit value constraint for addri36.sp instruction.
+
+ ``Iu08``
+ Unsigned immediate 8-bit value.
+
+ ``Iu09``
+ Unsigned immediate 9-bit value.
+
+ ``Is10``
+ Signed immediate 10-bit value.
+
+ ``Is11``
+ Signed immediate 11-bit value.
+
+ ``Is15``
+ Signed immediate 15-bit value.
+
+ ``Iu15``
+ Unsigned immediate 15-bit value.
+
+ ``Ic15``
+ A constant which is not in the range of imm15u but ok for bclr instruction.
+
+ ``Ie15``
+ A constant which is not in the range of imm15u but ok for bset instruction.
+
+ ``It15``
+ A constant which is not in the range of imm15u but ok for btgl instruction.
+
+ ``Ii15``
+ A constant whose compliment value is in the range of imm15u
+ and ok for bitci instruction.
+
+ ``Is16``
+ Signed immediate 16-bit value.
+
+ ``Is17``
+ Signed immediate 17-bit value.
+
+ ``Is19``
+ Signed immediate 19-bit value.
+
+ ``Is20``
+ Signed immediate 20-bit value.
+
+ ``Ihig``
+ The immediate value that can be simply set high 20-bit.
+
+ ``Izeb``
+ The immediate value 0xff.
+
+ ``Izeh``
+ The immediate value 0xffff.
+
+ ``Ixls``
+ The immediate value 0x01.
+
+ ``Ix11``
+ The immediate value 0x7ff.
+
+ ``Ibms``
+ The immediate value with power of 2.
+
+ ``Ifex``
+ The immediate value with power of 2 minus 1.
+
+ ``U33``
+ Memory constraint for 333 format.
+
+ ``U45``
+ Memory constraint for 45 format.
+
+ ``U37``
+ Memory constraint for 37 format.
+
+Nios II family---:samp:`{config/nios2/constraints.md}`
+
+ ``I``
+ Integer that is valid as an immediate operand in an
+ instruction taking a signed 16-bit number. Range
+ -32768 to 32767.
+
+ ``J``
+ Integer that is valid as an immediate operand in an
+ instruction taking an unsigned 16-bit number. Range
+ 0 to 65535.
+
+ ``K``
+ Integer that is valid as an immediate operand in an
+ instruction taking only the upper 16-bits of a
+ 32-bit number. Range 32-bit numbers with the lower
+ 16-bits being 0.
+
+ ``L``
+ Integer that is valid as an immediate operand for a
+ shift instruction. Range 0 to 31.
+
+ ``M``
+ Integer that is valid as an immediate operand for
+ only the value 0. Can be used in conjunction with
+ the format modifier ``z`` to use ``r0``
+ instead of ``0`` in the assembly output.
+
+ ``N``
+ Integer that is valid as an immediate operand for
+ a custom instruction opcode. Range 0 to 255.
+
+ ``P``
+ An immediate operand for R2 andchi/andci instructions.
+
+ ``S``
+ Matches immediates which are addresses in the small
+ data section and therefore can be added to ``gp``
+ as a 16-bit immediate to re-create their 32-bit value.
+
+ ``U``
+ Matches constants suitable as an operand for the rdprs and
+ cache instructions.
+
+ ``v``
+ A memory operand suitable for Nios II R2 load/store
+ exclusive instructions.
+
+ ``w``
+ A memory operand suitable for load/store IO and cache
+ instructions.
+
+ .. only:: gccint
+
+ ``T``
+ A ``const`` wrapped ``UNSPEC`` expression,
+ representing a supported PIC or TLS relocation.
+
+OpenRISC---:samp:`{config/or1k/constraints.md}`
+
+ ``I``
+ Integer that is valid as an immediate operand in an
+ instruction taking a signed 16-bit number. Range
+ -32768 to 32767.
+
+ ``K``
+ Integer that is valid as an immediate operand in an
+ instruction taking an unsigned 16-bit number. Range
+ 0 to 65535.
+
+ ``M``
+ Signed 16-bit constant shifted left 16 bits. (Used with ``l.movhi`` )
+
+ ``O``
+ Zero
+
+ .. only:: gccint
+
+ ``c``
+ Register usable for sibcalls.
+
+PDP-11---:samp:`{config/pdp11/constraints.md}`
+
+ ``a``
+ Floating point registers AC0 through AC3. These can be loaded from/to
+ memory with a single instruction.
+
+ ``d``
+ Odd numbered general registers (R1, R3, R5). These are used for
+ 16-bit multiply operations.
+
+ ``D``
+ A memory reference that is encoded within the opcode, but not
+ auto-increment or auto-decrement.
+
+ ``f``
+ Any of the floating point registers (AC0 through AC5).
+
+ ``G``
+ Floating point constant 0.
+
+ ``h``
+ Floating point registers AC4 and AC5. These cannot be loaded from/to
+ memory with a single instruction.
+
+ ``I``
+ An integer constant that fits in 16 bits.
+
+ ``J``
+ An integer constant whose low order 16 bits are zero.
+
+ ``K``
+ An integer constant that does not meet the constraints for codes
+ :samp:`I` or :samp:`J`.
+
+ ``L``
+ The integer constant 1.
+
+ ``M``
+ The integer constant -1.
+
+ ``N``
+ The integer constant 0.
+
+ ``O``
+ Integer constants 0 through 3; shifts by these
+ amounts are handled as multiple single-bit shifts rather than a single
+ variable-length shift.
+
+ ``Q``
+ A memory reference which requires an additional word (address or
+ offset) after the opcode.
+
+ ``R``
+ A memory reference that is encoded within the opcode.
+
+PowerPC and IBM RS6000---:samp:`{config/rs6000/constraints.md}`
+
+ ``r``
+ A general purpose register (GPR), ``r0``... ``r31``.
+
+ ``b``
+ A base register. Like ``r``, but ``r0`` is not allowed, so
+ ``r1``... ``r31``.
+
+ ``f``
+ A floating point register (FPR), ``f0``... ``f31``.
+
+ ``d``
+ A floating point register. This is the same as ``f`` nowadays;
+ historically ``f`` was for single-precision and ``d`` was for
+ double-precision floating point.
+
+ ``v``
+ An Altivec vector register (VR), ``v0``... ``v31``.
+
+ ``wa``
+ A VSX register (VSR), ``vs0``... ``vs63``. This is either an
+ FPR ( ``vs0``... ``vs31`` are ``f0``... ``f31`` ) or a VR
+ ( ``vs32``... ``vs63`` are ``v0``... ``v31`` ).
+
+ When using ``wa``, you should use the ``%x`` output modifier, so that
+ the correct register number is printed. For example:
+
+ .. code-block:: c++
+
+ asm ("xvadddp %x0,%x1,%x2"
+ : "=wa" (v1)
+ : "wa" (v2), "wa" (v3));
+
+ You should not use ``%x`` for ``v`` operands:
+
+ .. code-block:: c++
+
+ asm ("xsaddqp %0,%1,%2"
+ : "=v" (v1)
+ : "v" (v2), "v" (v3));
+
+
+ .. only:: gccint
+
+ ``h``
+ A special register ( ``vrsave``, ``ctr``, or ``lr`` ).
+
+ ``c``
+ The count register, ``ctr``.
+
+ ``l``
+ The link register, ``lr``.
+
+ ``x``
+ Condition register field 0, ``cr0``.
+
+ ``y``
+ Any condition register field, ``cr0``... ``cr7``.
+
+ .. only:: gccint
+
+ ``z``
+ The carry bit, ``XER[CA]``.
+
+ ``we``
+ Like ``wa``, if :option:`-mpower9-vector` and :option:`-m64` are used;
+ otherwise, ``NO_REGS``.
+
+ ``wn``
+ No register ( ``NO_REGS`` ).
+
+ ``wr``
+ Like ``r``, if :option:`-mpowerpc64` is used; otherwise, ``NO_REGS``.
+
+ ``wx``
+ Like ``d``, if :option:`-mpowerpc-gfxopt` is used; otherwise, ``NO_REGS``.
+
+ ``wA``
+ Like ``b``, if :option:`-mpowerpc64` is used; otherwise, ``NO_REGS``.
+
+ ``wB``
+ Signed 5-bit constant integer that can be loaded into an Altivec register.
+
+ ``wD``
+ Int constant that is the element number of the 64-bit scalar in a vector.
+
+ ``wE``
+ Vector constant that can be loaded with the XXSPLTIB instruction.
+
+ ``wF``
+ Memory operand suitable for power8 GPR load fusion.
+
+ ``wL``
+ Int constant that is the element number mfvsrld accesses in a vector.
+
+ ``wM``
+ Match vector constant with all 1's if the XXLORC instruction is available.
+
+ ``wO``
+ Memory operand suitable for the ISA 3.0 vector d-form instructions.
+
+ ``wQ``
+ Memory operand suitable for the load/store quad instructions.
+
+ ``wS``
+ Vector constant that can be loaded with XXSPLTIB & sign extension.
+
+ ``wY``
+ A memory operand for a DS-form instruction.
+
+ ``wZ``
+ An indexed or indirect memory operand, ignoring the bottom 4 bits.
+
+ ``I``
+ A signed 16-bit constant.
+
+ ``J``
+ An unsigned 16-bit constant shifted left 16 bits (use ``L`` instead
+ for ``SImode`` constants).
+
+ ``K``
+ An unsigned 16-bit constant.
+
+ ``L``
+ A signed 16-bit constant shifted left 16 bits.
+
+ .. only:: gccint
+
+ ``M``
+ An integer constant greater than 31.
+
+ ``N``
+ An exact power of 2.
+
+ ``O``
+ The integer constant zero.
+
+ ``P``
+ A constant whose negation is a signed 16-bit constant.
+
+ ``eI``
+ A signed 34-bit integer constant if prefixed instructions are supported.
+
+ .. only:: gccint
+
+ ``G``
+ A floating point constant that can be loaded into a register with one
+ instruction per word.
+
+ ``H``
+ A floating point constant that can be loaded into a register using
+ three instructions.
+
+ ``m``
+ A memory operand.
+ Normally, ``m`` does not allow addresses that update the base register.
+ If the ``<`` or ``>`` constraint is also used, they are allowed and
+ therefore on PowerPC targets in that case it is only safe
+ to use ``m<>`` in an ``asm`` statement if that ``asm`` statement
+ accesses the operand exactly once. The ``asm`` statement must also
+ use ``%U<opno>`` as a placeholder for the 'update' flag in the
+ corresponding load or store instruction. For example:
+
+ .. code-block:: c++
+
+ asm ("st%U0 %1,%0" : "=m<>" (mem) : "r" (val));
+
+ is correct but:
+
+ .. code-block:: c++
+
+ asm ("st %1,%0" : "=m<>" (mem) : "r" (val));
+
+ is not.
+
+ .. only:: gccint
+
+ ``es``
+ A 'stable' memory operand; that is, one which does not include any
+ automodification of the base register. This used to be useful when
+ ``m`` allowed automodification of the base register, but as those
+ are now only allowed when ``<`` or ``>`` is used, ``es`` is
+ basically the same as ``m`` without ``<`` and ``>``.
+
+ ``Q``
+ A memory operand addressed by just a base register.
+
+ .. only:: gccint
+
+ ``Y``
+ A memory operand for a DQ-form instruction.
+
+ ``Z``
+ A memory operand accessed with indexed or indirect addressing.
+
+ .. only:: gccint
+
+ ``R``
+ An AIX TOC entry.
+
+ ``a``
+ An indexed or indirect address.
+
+ .. only:: gccint
+
+ ``U``
+ A V.4 small data reference.
+
+ ``W``
+ A vector constant that does not require memory.
+
+ ``j``
+ The zero vector constant.
+
+PRU---:samp:`{config/pru/constraints.md}`
+
+ ``I``
+ An unsigned 8-bit integer constant.
+
+ ``J``
+ An unsigned 16-bit integer constant.
+
+ ``L``
+ An unsigned 5-bit integer constant (for shift counts).
+
+ ``T``
+ A text segment (program memory) constant label.
+
+ ``Z``
+ Integer constant zero.
+
+RL78---:samp:`{config/rl78/constraints.md}`
+
+ ``Int3``
+ An integer constant in the range 1 ... 7.
+
+ ``Int8``
+ An integer constant in the range 0 ... 255.
+
+ ``J``
+ An integer constant in the range -255 ... 0
+
+ ``K``
+ The integer constant 1.
+
+ ``L``
+ The integer constant -1.
+
+ ``M``
+ The integer constant 0.
+
+ ``N``
+ The integer constant 2.
+
+ ``O``
+ The integer constant -2.
+
+ ``P``
+ An integer constant in the range 1 ... 15.
+
+ ``Qbi``
+ The built-in compare types--eq, ne, gtu, ltu, geu, and leu.
+
+ ``Qsc``
+ The synthetic compare types--gt, lt, ge, and le.
+
+ ``Wab``
+ A memory reference with an absolute address.
+
+ ``Wbc``
+ A memory reference using ``BC`` as a base register, with an optional offset.
+
+ ``Wca``
+ A memory reference using ``AX``, ``BC``, ``DE``, or ``HL`` for the address, for calls.
+
+ ``Wcv``
+ A memory reference using any 16-bit register pair for the address, for calls.
+
+ ``Wd2``
+ A memory reference using ``DE`` as a base register, with an optional offset.
+
+ ``Wde``
+ A memory reference using ``DE`` as a base register, without any offset.
+
+ ``Wfr``
+ Any memory reference to an address in the far address space.
+
+ ``Wh1``
+ A memory reference using ``HL`` as a base register, with an optional one-byte offset.
+
+ ``Whb``
+ A memory reference using ``HL`` as a base register, with ``B`` or ``C`` as the index register.
+
+ ``Whl``
+ A memory reference using ``HL`` as a base register, without any offset.
+
+ ``Ws1``
+ A memory reference using ``SP`` as a base register, with an optional one-byte offset.
+
+ ``Y``
+ Any memory reference to an address in the near address space.
+
+ ``A``
+ The ``AX`` register.
+
+ ``B``
+ The ``BC`` register.
+
+ ``D``
+ The ``DE`` register.
+
+ ``R``
+ ``A`` through ``L`` registers.
+
+ ``S``
+ The ``SP`` register.
+
+ ``T``
+ The ``HL`` register.
+
+ ``Z08W``
+ The 16-bit ``R8`` register.
+
+ ``Z10W``
+ The 16-bit ``R10`` register.
+
+ ``Zint``
+ The registers reserved for interrupts ( ``R24`` to ``R31`` ).
+
+ ``a``
+ The ``A`` register.
+
+ ``b``
+ The ``B`` register.
+
+ ``c``
+ The ``C`` register.
+
+ ``d``
+ The ``D`` register.
+
+ ``e``
+ The ``E`` register.
+
+ ``h``
+ The ``H`` register.
+
+ ``l``
+ The ``L`` register.
+
+ ``v``
+ The virtual registers.
+
+ ``w``
+ The ``PSW`` register.
+
+ ``x``
+ The ``X`` register.
+
+RISC-V---:samp:`{config/riscv/constraints.md}`
+
+ ``f``
+ A floating-point register (if available).
+
+ ``I``
+ An I-type 12-bit signed immediate.
+
+ ``J``
+ Integer zero.
+
+ ``K``
+ A 5-bit unsigned immediate for CSR access instructions.
+
+ ``A``
+ An address that is held in a general-purpose register.
+
+RX---:samp:`{config/rx/constraints.md}`
+
+ ``Q``
+ An address which does not involve register indirect addressing or
+ pre/post increment/decrement addressing.
+
+ ``Symbol``
+ A symbol reference.
+
+ ``Int08``
+ A constant in the range -256 to 255, inclusive.
+
+ ``Sint08``
+ A constant in the range -128 to 127, inclusive.
+
+ ``Sint16``
+ A constant in the range -32768 to 32767, inclusive.
+
+ ``Sint24``
+ A constant in the range -8388608 to 8388607, inclusive.
+
+ ``Uint04``
+ A constant in the range 0 to 15, inclusive.
+
+S/390 and zSeries---:samp:`{config/s390/s390.h}`
+
+ ``a``
+ Address register (general purpose register except r0)
+
+ ``c``
+ Condition code register
+
+ ``d``
+ Data register (arbitrary general purpose register)
+
+ ``f``
+ Floating-point register
+
+ ``I``
+ Unsigned 8-bit constant (0--255)
+
+ ``J``
+ Unsigned 12-bit constant (0--4095)
+
+ ``K``
+ Signed 16-bit constant (-32768--32767)
+
+ ``L``
+ Value appropriate as displacement.
+
+ ``(0..4095)``
+ for short displacement
+
+ ``(-524288..524287)``
+ for long displacement
+
+ ``M``
+ Constant integer with a value of 0x7fffffff.
+
+ ``N``
+ Multiple letter constraint followed by 4 parameter letters.
+
+ ``0..9:``
+ number of the part counting from most to least significant
+
+ ``H,Q:``
+ mode of the part
+
+ ``D,S,H:``
+ mode of the containing operand
+
+ ``0,F:``
+ value of the other parts (F---all bits set)
+
+ The constraint matches if the specified part of a constant
+ has a value different from its other parts.
+
+ ``Q``
+ Memory reference without index register and with short displacement.
+
+ ``R``
+ Memory reference with index register and short displacement.
+
+ ``S``
+ Memory reference without index register but with long displacement.
+
+ ``T``
+ Memory reference with index register and long displacement.
+
+ ``U``
+ Pointer with short displacement.
+
+ ``W``
+ Pointer with long displacement.
+
+ ``Y``
+ Shift count operand.
+
+SPARC---:samp:`{config/sparc/sparc.h}`
+
+ ``f``
+ Floating-point register on the SPARC-V8 architecture and
+ lower floating-point register on the SPARC-V9 architecture.
+
+ ``e``
+ Floating-point register. It is equivalent to :samp:`f` on the
+ SPARC-V8 architecture and contains both lower and upper
+ floating-point registers on the SPARC-V9 architecture.
+
+ ``c``
+ Floating-point condition code register.
+
+ ``d``
+ Lower floating-point register. It is only valid on the SPARC-V9
+ architecture when the Visual Instruction Set is available.
+
+ ``b``
+ Floating-point register. It is only valid on the SPARC-V9 architecture
+ when the Visual Instruction Set is available.
+
+ ``h``
+ 64-bit global or out register for the SPARC-V8+ architecture.
+
+ ``C``
+ The constant all-ones, for floating-point.
+
+ ``A``
+ Signed 5-bit constant
+
+ ``D``
+ A vector constant
+
+ ``I``
+ Signed 13-bit constant
+
+ ``J``
+ Zero
+
+ ``K``
+ 32-bit constant with the low 12 bits clear (a constant that can be
+ loaded with the ``sethi`` instruction)
+
+ ``L``
+ A constant in the range supported by ``movcc`` instructions (11-bit
+ signed immediate)
+
+ ``M``
+ A constant in the range supported by ``movrcc`` instructions (10-bit
+ signed immediate)
+
+ ``N``
+ Same as :samp:`K`, except that it verifies that bits that are not in the
+ lower 32-bit range are all zero. Must be used instead of :samp:`K` for
+ modes wider than ``SImode``
+
+ ``O``
+ The constant 4096
+
+ ``G``
+ Floating-point zero
+
+ ``H``
+ Signed 13-bit constant, sign-extended to 32 or 64 bits
+
+ ``P``
+ The constant -1
+
+ ``Q``
+ Floating-point constant whose integral representation can
+ be moved into an integer register using a single sethi
+ instruction
+
+ ``R``
+ Floating-point constant whose integral representation can
+ be moved into an integer register using a single mov
+ instruction
+
+ ``S``
+ Floating-point constant whose integral representation can
+ be moved into an integer register using a high/lo_sum
+ instruction sequence
+
+ ``T``
+ Memory address aligned to an 8-byte boundary
+
+ ``U``
+ Even register
+
+ ``W``
+ Memory address for :samp:`e` constraint registers
+
+ ``w``
+ Memory address with only a base register
+
+ ``Y``
+ Vector zero
+
+TI C6X family---:samp:`{config/c6x/constraints.md}`
+
+ ``a``
+ Register file A (A0--A31).
+
+ ``b``
+ Register file B (B0--B31).
+
+ ``A``
+ Predicate registers in register file A (A0--A2 on C64X and
+ higher, A1 and A2 otherwise).
+
+ ``B``
+ Predicate registers in register file B (B0--B2).
+
+ ``C``
+ A call-used register in register file B (B0--B9, B16--B31).
+
+ ``Da``
+ Register file A, excluding predicate registers (A3--A31,
+ plus A0 if not C64X or higher).
+
+ ``Db``
+ Register file B, excluding predicate registers (B3--B31).
+
+ ``Iu4``
+ Integer constant in the range 0 ... 15.
+
+ ``Iu5``
+ Integer constant in the range 0 ... 31.
+
+ ``In5``
+ Integer constant in the range -31 ... 0.
+
+ ``Is5``
+ Integer constant in the range -16 ... 15.
+
+ ``I5x``
+ Integer constant that can be the operand of an ADDA or a SUBA insn.
+
+ ``IuB``
+ Integer constant in the range 0 ... 65535.
+
+ ``IsB``
+ Integer constant in the range -32768 ... 32767.
+
+ ``IsC``
+ Integer constant in the range -2^{20} ... 2^{20} - 1.
+
+ ``Jc``
+ Integer constant that is a valid mask for the clr instruction.
+
+ ``Js``
+ Integer constant that is a valid mask for the set instruction.
+
+ ``Q``
+ Memory location with A base register.
+
+ ``R``
+ Memory location with B base register.
+
+ .. only:: gccint
+
+ ``S0``
+ On C64x+ targets, a GP-relative small data reference.
+
+ ``S1``
+ Any kind of ``SYMBOL_REF``, for use in a call address.
+
+ ``Si``
+ Any kind of immediate operand, unless it matches the S0 constraint.
+
+ ``T``
+ Memory location with B base register, but not using a long offset.
+
+ ``W``
+ A memory operand with an address that cannot be used in an unaligned access.
+
+ ``Z``
+ Register B14 (aka DP).
+
+TILE-Gx---:samp:`{config/tilegx/constraints.md}`
+
+ ``R00`` ``R01`` ``R02`` ``R03`` ``R04`` ``R05`` ``R06`` ``R07`` ``R08`` ``R09`` ``R10``
+ Each of these represents a register constraint for an individual
+ register, from r0 to r10.
+
+ ``I``
+ Signed 8-bit integer constant.
+
+ ``J``
+ Signed 16-bit integer constant.
+
+ ``K``
+ Unsigned 16-bit integer constant.
+
+ ``L``
+ Integer constant that fits in one signed byte when incremented by one
+ (-129 ... 126).
+
+ ``m``
+ Memory operand. If used together with :samp:`<` or :samp:`>`, the
+ operand can have postincrement which requires printing with :samp:`%In`
+ and :samp:`%in` on TILE-Gx. For example:
+
+ .. code-block:: c++
+
+ asm ("st_add %I0,%1,%i0" : "=m<>" (*mem) : "r" (val));
+
+ ``M``
+ A bit mask suitable for the BFINS instruction.
+
+ ``N``
+ Integer constant that is a byte tiled out eight times.
+
+ ``O``
+ The integer zero constant.
+
+ ``P``
+ Integer constant that is a sign-extended byte tiled out as four shorts.
+
+ ``Q``
+ Integer constant that fits in one signed byte when incremented
+ (-129 ... 126), but excluding -1.
+
+ ``S``
+ Integer constant that has all 1 bits consecutive and starting at bit 0.
+
+ ``T``
+ A 16-bit fragment of a got, tls, or pc-relative reference.
+
+ ``U``
+ Memory operand except postincrement. This is roughly the same as
+ :samp:`m` when not used together with :samp:`<` or :samp:`>`.
+
+ ``W``
+ An 8-element vector constant with identical elements.
+
+ ``Y``
+ A 4-element vector constant with identical elements.
+
+ ``Z0``
+ The integer constant 0xffffffff.
+
+ ``Z1``
+ The integer constant 0xffffffff00000000.
+
+TILEPro---:samp:`{config/tilepro/constraints.md}`
+
+ ``R00`` ``R01`` ``R02`` ``R03`` ``R04`` ``R05`` ``R06`` ``R07`` ``R08`` ``R09`` ``R10``
+ Each of these represents a register constraint for an individual
+ register, from r0 to r10.
+
+ ``I``
+ Signed 8-bit integer constant.
+
+ ``J``
+ Signed 16-bit integer constant.
+
+ ``K``
+ Nonzero integer constant with low 16 bits zero.
+
+ ``L``
+ Integer constant that fits in one signed byte when incremented by one
+ (-129 ... 126).
+
+ ``m``
+ Memory operand. If used together with :samp:`<` or :samp:`>`, the
+ operand can have postincrement which requires printing with :samp:`%In`
+ and :samp:`%in` on TILEPro. For example:
+
+ .. code-block:: c++
+
+ asm ("swadd %I0,%1,%i0" : "=m<>" (mem) : "r" (val));
+
+ ``M``
+ A bit mask suitable for the MM instruction.
+
+ ``N``
+ Integer constant that is a byte tiled out four times.
+
+ ``O``
+ The integer zero constant.
+
+ ``P``
+ Integer constant that is a sign-extended byte tiled out as two shorts.
+
+ ``Q``
+ Integer constant that fits in one signed byte when incremented
+ (-129 ... 126), but excluding -1.
+
+ ``T``
+ A symbolic operand, or a 16-bit fragment of a got, tls, or pc-relative
+ reference.
+
+ ``U``
+ Memory operand except postincrement. This is roughly the same as
+ :samp:`m` when not used together with :samp:`<` or :samp:`>`.
+
+ ``W``
+ A 4-element vector constant with identical elements.
+
+ ``Y``
+ A 2-element vector constant with identical elements.
+
+Visium---:samp:`{config/visium/constraints.md}`
+
+ ``b``
+ EAM register ``mdb``
+
+ ``c``
+ EAM register ``mdc``
+
+ ``f``
+ Floating point register
+
+ .. only:: gccint
+
+ ``k``
+ Register for sibcall optimization
+
+ ``l``
+ General register, but not ``r29``, ``r30`` and ``r31``
+
+ ``t``
+ Register ``r1``
+
+ ``u``
+ Register ``r2``
+
+ ``v``
+ Register ``r3``
+
+ ``G``
+ Floating-point constant 0.0
+
+ ``J``
+ Integer constant in the range 0 .. 65535 (16-bit immediate)
+
+ ``K``
+ Integer constant in the range 1 .. 31 (5-bit immediate)
+
+ ``L``
+ Integer constant in the range -65535 .. -1 (16-bit negative immediate)
+
+ ``M``
+ Integer constant -1
+
+ ``O``
+ Integer constant 0
+
+ ``P``
+ Integer constant 32
+
+x86 family---:samp:`{config/i386/constraints.md}`
+
+ ``R``
+ Legacy register---the eight integer registers available on all
+ i386 processors ( ``a``, ``b``, ``c``, ``d``,
+ ``si``, ``di``, ``bp``, ``sp`` ).
+
+ ``q``
+ Any register accessible as ``rl``. In 32-bit mode, ``a``,
+ ``b``, ``c``, and ``d`` ; in 64-bit mode, any integer register.
+
+ ``Q``
+ Any register accessible as ``rh`` : ``a``, ``b``,
+ ``c``, and ``d``.
+
+ .. only:: gccint
+
+ ``l``
+ Any register that can be used as the index in a base+index memory
+ access: that is, any general register except the stack pointer.
+
+ ``a``
+ The ``a`` register.
+
+ ``b``
+ The ``b`` register.
+
+ ``c``
+ The ``c`` register.
+
+ ``d``
+ The ``d`` register.
+
+ ``S``
+ The ``si`` register.
+
+ ``D``
+ The ``di`` register.
+
+ ``A``
+ The ``a`` and ``d`` registers. This class is used for instructions
+ that return double word results in the ``ax:dx`` register pair. Single
+ word values will be allocated either in ``ax`` or ``dx``.
+ For example on i386 the following implements ``rdtsc`` :
+
+ .. code-block:: c++
+
+ unsigned long long rdtsc (void)
+ {
+ unsigned long long tick;
+ __asm__ __volatile__("rdtsc":"=A"(tick));
+ return tick;
+ }
+
+ This is not correct on x86-64 as it would allocate tick in either ``ax``
+ or ``dx``. You have to use the following variant instead:
+
+ .. code-block:: c++
+
+ unsigned long long rdtsc (void)
+ {
+ unsigned int tickl, tickh;
+ __asm__ __volatile__("rdtsc":"=a"(tickl),"=d"(tickh));
+ return ((unsigned long long)tickh << 32)|tickl;
+ }
+
+ ``U``
+ The call-clobbered integer registers.
+
+ ``f``
+ Any 80387 floating-point (stack) register.
+
+ ``t``
+ Top of 80387 floating-point stack ( ``%st(0)`` ).
+
+ ``u``
+ Second from top of 80387 floating-point stack ( ``%st(1)`` ).
+
+ .. only:: gccint
+
+ ``Yk``
+ Any mask register that can be used as a predicate, i.e. ``k1-k7``.
+
+ ``k``
+ Any mask register.
+
+ ``y``
+ Any MMX register.
+
+ ``x``
+ Any SSE register.
+
+ ``v``
+ Any EVEX encodable SSE register ( ``%xmm0-%xmm31`` ).
+
+ .. only:: gccint
+
+ ``w``
+ Any bound register.
+
+ ``Yz``
+ First SSE register ( ``%xmm0`` ).
+
+ .. only:: gccint
+
+ ``Yi``
+ Any SSE register, when SSE2 and inter-unit moves are enabled.
+
+ ``Yj``
+ Any SSE register, when SSE2 and inter-unit moves from vector registers are enabled.
+
+ ``Ym``
+ Any MMX register, when inter-unit moves are enabled.
+
+ ``Yn``
+ Any MMX register, when inter-unit moves from vector registers are enabled.
+
+ ``Yp``
+ Any integer register when ``TARGET_PARTIAL_REG_STALL`` is disabled.
+
+ ``Ya``
+ Any integer register when zero extensions with ``AND`` are disabled.
+
+ ``Yb``
+ Any register that can be used as the GOT base when calling
+
+ ``___tls_get_addr`` : that is, any general register except ``a``
+ and ``sp`` registers, for :option:`-fno-plt` if linker supports it.
+ Otherwise, ``b`` register.
+
+ ``Yf``
+ Any x87 register when 80387 floating-point arithmetic is enabled.
+
+ ``Yr``
+ Lower SSE register when avoiding REX prefix and all SSE registers otherwise.
+
+ ``Yv``
+ For AVX512VL, any EVEX-encodable SSE register ( ``%xmm0-%xmm31`` ),
+ otherwise any SSE register.
+
+ ``Yh``
+ Any EVEX-encodable SSE register, that has number factor of four.
+
+ ``Bf``
+ Flags register operand.
+
+ ``Bg``
+ GOT memory operand.
+
+ ``Bm``
+ Vector memory operand.
+
+ ``Bc``
+ Constant memory operand.
+
+ ``Bn``
+ Memory operand without REX prefix.
+
+ ``Bs``
+ Sibcall memory operand.
+
+ ``Bw``
+ Call memory operand.
+
+ ``Bz``
+ Constant call address operand.
+
+ ``BC``
+ SSE constant -1 operand.
+
+ ``I``
+ Integer constant in the range 0 ... 31, for 32-bit shifts.
+
+ ``J``
+ Integer constant in the range 0 ... 63, for 64-bit shifts.
+
+ ``K``
+ Signed 8-bit integer constant.
+
+ ``L``
+ ``0xFF`` or ``0xFFFF``, for andsi as a zero-extending move.
+
+ ``M``
+ 0, 1, 2, or 3 (shifts for the ``lea`` instruction).
+
+ ``N``
+ Unsigned 8-bit integer constant (for ``in`` and ``out``
+ instructions).
+
+ .. only:: gccint
+
+ ``O``
+ Integer constant in the range 0 ... 127, for 128-bit shifts.
+
+ ``G``
+ Standard 80387 floating point constant.
+
+ ``C``
+ SSE constant zero operand.
+
+ ``e``
+ 32-bit signed integer constant, or a symbolic reference known
+ to fit that range (for immediate operands in sign-extending x86-64
+ instructions).
+
+ ``We``
+ 32-bit signed integer constant, or a symbolic reference known
+ to fit that range (for sign-extending conversion operations that
+ require non- ``VOIDmode`` immediate operands).
+
+ ``Wz``
+ 32-bit unsigned integer constant, or a symbolic reference known
+ to fit that range (for zero-extending conversion operations that
+ require non- ``VOIDmode`` immediate operands).
+
+ ``Wd``
+ 128-bit integer constant where both the high and low 64-bit word
+ satisfy the ``e`` constraint.
+
+ ``Z``
+ 32-bit unsigned integer constant, or a symbolic reference known
+ to fit that range (for immediate operands in zero-extending x86-64
+ instructions).
+
+ ``Tv``
+ VSIB address operand.
+
+ ``Ts``
+ Address operand without segment register.
+
+Xstormy16---:samp:`{config/stormy16/stormy16.h}`
+
+ ``a``
+ Register r0.
+
+ ``b``
+ Register r1.
+
+ ``c``
+ Register r2.
+
+ ``d``
+ Register r8.
+
+ ``e``
+ Registers r0 through r7.
+
+ ``t``
+ Registers r0 and r1.
+
+ ``y``
+ The carry register.
+
+ ``z``
+ Registers r8 and r9.
+
+ ``I``
+ A constant between 0 and 3 inclusive.
+
+ ``J``
+ A constant that has exactly one bit set.
+
+ ``K``
+ A constant that has exactly one bit clear.
+
+ ``L``
+ A constant between 0 and 255 inclusive.
+
+ ``M``
+ A constant between -255 and 0 inclusive.
+
+ ``N``
+ A constant between -3 and 0 inclusive.
+
+ ``O``
+ A constant between 1 and 4 inclusive.
+
+ ``P``
+ A constant between -4 and -1 inclusive.
+
+ ``Q``
+ A memory reference that is a stack push.
+
+ ``R``
+ A memory reference that is a stack pop.
+
+ ``S``
+ A memory reference that refers to a constant address of known value.
+
+ ``T``
+ The register indicated by Rx (not implemented yet).
+
+ ``U``
+ A constant that is not between 2 and 15 inclusive.
+
+ ``Z``
+ The constant 0.
+
+Xtensa---:samp:`{config/xtensa/constraints.md}`
+
+ ``a``
+ General-purpose 32-bit register
+
+ ``b``
+ One-bit boolean register
+
+ ``A``
+ MAC16 40-bit accumulator register
+
+ ``I``
+ Signed 12-bit integer constant, for use in MOVI instructions
+
+ ``J``
+ Signed 8-bit integer constant, for use in ADDI instructions
+
+ ``K``
+ Integer constant valid for BccI instructions
+
+ ``L``
+ Unsigned constant valid for BccUI instructions
\ No newline at end of file
diff --git a/gcc/doc/cpp/character-sets.rst b/gcc/doc/cpp/character-sets.rst
new file mode 100644
index 00000000000..e31934ac79b
--- /dev/null
+++ b/gcc/doc/cpp/character-sets.rst
@@ -0,0 +1,56 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _character-sets:
+
+Character sets
+**************
+
+Source code character set processing in C and related languages is
+rather complicated. The C standard discusses two character sets, but
+there are really at least four.
+
+The files input to CPP might be in any character set at all. CPP's
+very first action, before it even looks for line boundaries, is to
+convert the file into the character set it uses for internal
+processing. That set is what the C standard calls the :dfn:`source`
+character set. It must be isomorphic with ISO 10646, also known as
+Unicode. CPP uses the UTF-8 encoding of Unicode.
+
+The character sets of the input files are specified using the
+:option:`-finput-charset` = option.
+
+All preprocessing work (the subject of the rest of this manual) is
+carried out in the source character set. If you request textual
+output from the preprocessor with the :option:`-E` option, it will be
+in UTF-8.
+
+After preprocessing is complete, string and character constants are
+converted again, into the :dfn:`execution` character set. This
+character set is under control of the user; the default is UTF-8,
+matching the source character set. Wide string and character
+constants have their own character set, which is not called out
+specifically in the standard. Again, it is under control of the user.
+The default is UTF-16 or UTF-32, whichever fits in the target's
+``wchar_t`` type, in the target machine's byte
+order [#f1]_.
+
+Octal and hexadecimal escape sequences do not undergo
+conversion; ``'\x12'`` has the value 0x12 regardless of the currently
+selected execution character set. All other escapes are replaced by
+the character in the source character set that they represent, then
+converted to the execution character set, just like unescaped
+characters.
+
+In identifiers, characters outside the ASCII range can be specified
+with the :samp:`\\u` and :samp:`\\U` escapes or used directly in the input
+encoding. If strict ISO C90 conformance is specified with an option
+such as :option:`-std`:samp:`=c90`, or :option:`-fno-extended-identifiers` is
+used, then those constructs are not permitted in identifiers.
+
+.. [#f1] UTF-16 does not meet the requirements of the C
+ standard for a wide character set, but the choice of 16-bit
+ ``wchar_t`` is enshrined in some system ABIs so we cannot fix
+ this.
\ No newline at end of file
diff --git a/gcc/doc/cpp/conditional-syntax.rst b/gcc/doc/cpp/conditional-syntax.rst
new file mode 100644
index 00000000000..73311228508
--- /dev/null
+++ b/gcc/doc/cpp/conditional-syntax.rst
@@ -0,0 +1,413 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _conditional-syntax:
+
+Conditional Syntax
+******************
+
+.. index:: #if
+
+A conditional in the C preprocessor begins with a :dfn:`conditional
+directive`: :samp:`#if`, :samp:`#ifdef` or :samp:`#ifndef`.
+
+.. toctree::
+ :maxdepth: 2
+
+
+.. _ifdef:
+
+Ifdef
+^^^^^
+
+.. index:: #ifdef
+
+.. index:: #endif
+
+The simplest sort of conditional is
+
+.. code-block:: c++
+
+ #ifdef MACRO
+
+ controlled text
+
+ #endif /* MACRO */
+
+.. index:: conditional group
+
+This block is called a :dfn:`conditional group`. :samp:`{controlled text}`
+will be included in the output of the preprocessor if and only if
+:samp:`{MACRO}` is defined. We say that the conditional :dfn:`succeeds` if
+:samp:`{MACRO}` is defined, :dfn:`fails` if it is not.
+
+The :samp:`{controlled text}` inside of a conditional can include
+preprocessing directives. They are executed only if the conditional
+succeeds. You can nest conditional groups inside other conditional
+groups, but they must be completely nested. In other words,
+:samp:`#endif` always matches the nearest :samp:`#ifdef` (or
+:samp:`#ifndef`, or :samp:`#if`). Also, you cannot start a conditional
+group in one file and end it in another.
+
+Even if a conditional fails, the :samp:`{controlled text}` inside it is
+still run through initial transformations and tokenization. Therefore,
+it must all be lexically valid C. Normally the only way this matters is
+that all comments and string literals inside a failing conditional group
+must still be properly ended.
+
+The comment following the :samp:`#endif` is not required, but it is a
+good practice if there is a lot of :samp:`{controlled text}`, because it
+helps people match the :samp:`#endif` to the corresponding :samp:`#ifdef`.
+Older programs sometimes put :samp:`{MACRO}` directly after the
+:samp:`#endif` without enclosing it in a comment. This is invalid code
+according to the C standard. CPP accepts it with a warning. It
+never affects which :samp:`#ifndef` the :samp:`#endif` matches.
+
+.. index:: #ifndef
+
+Sometimes you wish to use some code if a macro is *not* defined.
+You can do this by writing :samp:`#ifndef` instead of :samp:`#ifdef`.
+One common use of :samp:`#ifndef` is to include code only the first
+time a header file is included. See :ref:`once-only-headers`.
+
+Macro definitions can vary between compilations for several reasons.
+Here are some samples.
+
+* Some macros are predefined on each kind of machine
+ (see :ref:`system-specific-predefined-macros`). This allows you to provide
+ code specially tuned for a particular machine.
+
+* System header files define more macros, associated with the features
+ they implement. You can test these macros with conditionals to avoid
+ using a system feature on a machine where it is not implemented.
+
+* Macros can be defined or undefined with the :option:`-D` and :option:`-U`
+ command-line options when you compile the program. You can arrange to
+ compile the same source file into two different programs by choosing a
+ macro name to specify which program you want, writing conditionals to
+ test whether or how this macro is defined, and then controlling the
+ state of the macro with command-line options, perhaps set in the
+ Makefile. See :ref:`invocation`.
+
+* Your program might have a special header file (often called
+ :samp:`config.h`) that is adjusted when the program is compiled. It can
+ define or not define macros depending on the features of the system and
+ the desired capabilities of the program. The adjustment can be
+ automated by a tool such as :command:`autoconf`, or done by hand.
+
+.. _if:
+
+If
+^^
+
+The :samp:`#if` directive allows you to test the value of an arithmetic
+expression, rather than the mere existence of one macro. Its syntax is
+
+.. code-block:: c++
+
+ #if expression
+
+ controlled text
+
+ #endif /* expression */
+
+:samp:`{expression}` is a C expression of integer type, subject to stringent
+restrictions. It may contain
+
+* Integer constants.
+
+* Character constants, which are interpreted as they would be in normal
+ code.
+
+* Arithmetic operators for addition, subtraction, multiplication,
+ division, bitwise operations, shifts, comparisons, and logical
+ operations ( ``&&`` and ``||`` ). The latter two obey the usual
+ short-circuiting rules of standard C.
+
+* Macros. All macros in the expression are expanded before actual
+ computation of the expression's value begins.
+
+* Uses of the ``defined`` operator, which lets you check whether macros
+ are defined in the middle of an :samp:`#if`.
+
+* Identifiers that are not macros, which are all considered to be the
+ number zero. This allows you to write ``#if MACRO`` instead of
+ ``#ifdef MACRO``, if you know that MACRO, when defined, will
+ always have a nonzero value. Function-like macros used without their
+ function call parentheses are also treated as zero.
+
+ In some contexts this shortcut is undesirable. The :option:`-Wundef`
+ option causes GCC to warn whenever it encounters an identifier which is
+ not a macro in an :samp:`#if`.
+
+The preprocessor does not know anything about types in the language.
+Therefore, ``sizeof`` operators are not recognized in :samp:`#if`, and
+neither are ``enum`` constants. They will be taken as identifiers
+which are not macros, and replaced by zero. In the case of
+``sizeof``, this is likely to cause the expression to be invalid.
+
+The preprocessor calculates the value of :samp:`{expression}`. It carries
+out all calculations in the widest integer type known to the compiler;
+on most machines supported by GCC this is 64 bits. This is not the same
+rule as the compiler uses to calculate the value of a constant
+expression, and may give different results in some cases. If the value
+comes out to be nonzero, the :samp:`#if` succeeds and the :samp:`{controlled
+text}` is included; otherwise it is skipped.
+
+.. _defined:
+
+Defined
+^^^^^^^
+
+.. index:: defined
+
+The special operator ``defined`` is used in :samp:`#if` and
+:samp:`#elif` expressions to test whether a certain name is defined as a
+macro. ``defined name`` and ``defined (name)`` are
+both expressions whose value is 1 if :samp:`{name}` is defined as a macro at
+the current point in the program, and 0 otherwise. Thus, ``#if
+defined MACRO`` is precisely equivalent to ``#ifdef MACRO``.
+
+``defined`` is useful when you wish to test more than one macro for
+existence at once. For example,
+
+.. code-block:: c++
+
+ #if defined (__vax__) || defined (__ns16000__)
+
+would succeed if either of the names ``__vax__`` or
+``__ns16000__`` is defined as a macro.
+
+Conditionals written like this:
+
+.. code-block:: c++
+
+ #if defined BUFSIZE && BUFSIZE >= 1024
+
+can generally be simplified to just ``#if BUFSIZE >= 1024``,
+since if ``BUFSIZE`` is not defined, it will be interpreted as having
+the value zero.
+
+If the ``defined`` operator appears as a result of a macro expansion,
+the C standard says the behavior is undefined. GNU cpp treats it as a
+genuine ``defined`` operator and evaluates it normally. It will warn
+wherever your code uses this feature if you use the command-line option
+:option:`-Wpedantic`, since other compilers may handle it differently. The
+warning is also enabled by :option:`-Wextra`, and can also be enabled
+individually with :option:`-Wexpansion-to-defined`.
+
+.. _else:
+
+Else
+^^^^
+
+.. index:: #else
+
+The :samp:`#else` directive can be added to a conditional to provide
+alternative text to be used if the condition fails. This is what it
+looks like:
+
+.. code-block:: c++
+
+ #if expression
+ text-if-true
+ #else /* Not expression */
+ text-if-false
+ #endif /* Not expression */
+
+If :samp:`{expression}` is nonzero, the :samp:`{text-if-true}` is included and
+the :samp:`{text-if-false}` is skipped. If :samp:`{expression}` is zero, the
+opposite happens.
+
+You can use :samp:`#else` with :samp:`#ifdef` and :samp:`#ifndef`, too.
+
+.. _elif:
+
+Elif
+^^^^
+
+.. index:: #elif
+
+One common case of nested conditionals is used to check for more than two
+possible alternatives. For example, you might have
+
+.. code-block:: c++
+
+ #if X == 1
+ ...
+ #else /* X != 1 */
+ #if X == 2
+ ...
+ #else /* X != 2 */
+ ...
+ #endif /* X != 2 */
+ #endif /* X != 1 */
+
+Another conditional directive, :samp:`#elif`, allows this to be
+abbreviated as follows:
+
+.. code-block:: c++
+
+ #if X == 1
+ ...
+ #elif X == 2
+ ...
+ #else /* X != 2 and X != 1*/
+ ...
+ #endif /* X != 2 and X != 1*/
+
+:samp:`#elif` stands for 'else if'. Like :samp:`#else`, it goes in the
+middle of a conditional group and subdivides it; it does not require a
+matching :samp:`#endif` of its own. Like :samp:`#if`, the :samp:`#elif`
+directive includes an expression to be tested. The text following the
+:samp:`#elif` is processed only if the original :samp:`#if`-condition
+failed and the :samp:`#elif` condition succeeds.
+
+More than one :samp:`#elif` can go in the same conditional group. Then
+the text after each :samp:`#elif` is processed only if the :samp:`#elif`
+condition succeeds after the original :samp:`#if` and all previous
+:samp:`#elif` directives within it have failed.
+
+:samp:`#else` is allowed after any number of :samp:`#elif` directives, but
+:samp:`#elif` may not follow :samp:`#else`.
+
+__has_attribute
+^^^^^^^^^^^^^^^
+
+.. index:: __has_attribute
+
+The special operator ``__has_attribute (operand)`` may be used
+in :samp:`#if` and :samp:`#elif` expressions to test whether the attribute
+referenced by its :samp:`{operand}` is recognized by GCC. Using the operator
+in other contexts is not valid. In C code, if compiling for strict
+conformance to standards before C2x, :samp:`{operand}` must be
+a valid identifier. Otherwise, :samp:`{operand}` may be optionally
+introduced by the ``attribute-scope::`` prefix.
+The :samp:`{attribute-scope}` prefix identifies the 'namespace' within
+which the attribute is recognized. The scope of GCC attributes is
+:samp:`gnu` or :samp:`__gnu__`. The ``__has_attribute`` operator by
+itself, without any :samp:`{operand}` or parentheses, acts as a predefined
+macro so that support for it can be tested in portable code. Thus,
+the recommended use of the operator is as follows:
+
+.. code-block:: c++
+
+ #if defined __has_attribute
+ # if __has_attribute (nonnull)
+ # define ATTR_NONNULL __attribute__ ((nonnull))
+ # endif
+ #endif
+
+The first :samp:`#if` test succeeds only when the operator is supported
+by the version of GCC (or another compiler) being used. Only when that
+test succeeds is it valid to use ``__has_attribute`` as a preprocessor
+operator. As a result, combining the two tests into a single expression as
+shown below would only be valid with a compiler that supports the operator
+but not with others that don't.
+
+.. code-block:: c++
+
+ #if defined __has_attribute && __has_attribute (nonnull) /* not portable */
+ ...
+ #endif
+
+__has_cpp_attribute
+^^^^^^^^^^^^^^^^^^^
+
+.. index:: __has_cpp_attribute
+
+The special operator ``__has_cpp_attribute (operand)`` may be used
+in :samp:`#if` and :samp:`#elif` expressions in C++ code to test whether
+the attribute referenced by its :samp:`{operand}` is recognized by GCC.
+``__has_cpp_attribute (operand)`` is equivalent to
+``__has_attribute (operand)`` except that when :samp:`{operand}`
+designates a supported standard attribute it evaluates to an integer
+constant of the form ``YYYYMM`` indicating the year and month when
+the attribute was first introduced into the C++ standard. For additional
+information including the dates of the introduction of current standard
+attributes, see `SD-6: SG10 Feature Test Recommendations <https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations/>`_.
+
+__has_c_attribute
+^^^^^^^^^^^^^^^^^
+
+.. index:: __has_c_attribute
+
+The special operator ``__has_c_attribute (operand)`` may be
+used in :samp:`#if` and :samp:`#elif` expressions in C code to test
+whether the attribute referenced by its :samp:`{operand}` is recognized by
+GCC in attributes using the :samp:`[[]]` syntax. GNU attributes must
+be specified with the scope :samp:`gnu` or :samp:`__gnu__` with
+``__has_c_attribute``. When :samp:`{operand}` designates a supported
+standard attribute it evaluates to an integer constant of the form
+``YYYYMM`` indicating the year and month when the attribute was
+first introduced into the C standard, or when the syntax of operands
+to the attribute was extended in the C standard.
+
+__has_builtin
+^^^^^^^^^^^^^
+
+.. index:: __has_builtin
+
+The special operator ``__has_builtin (operand)`` may be used in
+constant integer contexts and in preprocessor :samp:`#if` and :samp:`#elif`
+expressions to test whether the symbol named by its :samp:`{operand}` is
+recognized as a built-in function by GCC in the current language and
+conformance mode. It evaluates to a constant integer with a nonzero
+value if the argument refers to such a function, and to zero otherwise.
+The operator may also be used in preprocessor :samp:`#if` and :samp:`#elif`
+expressions. The ``__has_builtin`` operator by itself, without any
+:samp:`{operand}` or parentheses, acts as a predefined macro so that support
+for it can be tested in portable code. Thus, the recommended use of
+the operator is as follows:
+
+.. code-block:: c++
+
+ #if defined __has_builtin
+ # if __has_builtin (__builtin_object_size)
+ # define builtin_object_size(ptr) __builtin_object_size (ptr, 2)
+ # endif
+ #endif
+ #ifndef builtin_object_size
+ # define builtin_object_size(ptr) ((size_t)-1)
+ #endif
+
+__has_include
+^^^^^^^^^^^^^
+
+.. index:: __has_include
+
+The special operator ``__has_include (operand)`` may be used in
+:samp:`#if` and :samp:`#elif` expressions to test whether the header referenced
+by its :samp:`{operand}` can be included using the :samp:`#include` directive. Using
+the operator in other contexts is not valid. The :samp:`{operand}` takes
+the same form as the file in the :samp:`#include` directive (see :ref:`include-syntax`) and evaluates to a nonzero value if the header can be included and
+to zero otherwise. Note that that the ability to include a header doesn't
+imply that the header doesn't contain invalid constructs or :samp:`#error`
+directives that would cause the preprocessor to fail.
+
+The ``__has_include`` operator by itself, without any :samp:`{operand}` or
+parentheses, acts as a predefined macro so that support for it can be tested
+in portable code. Thus, the recommended use of the operator is as follows:
+
+.. code-block:: c++
+
+ #if defined __has_include
+ # if __has_include (<stdatomic.h>)
+ # include <stdatomic.h>
+ # endif
+ #endif
+
+The first :samp:`#if` test succeeds only when the operator is supported
+by the version of GCC (or another compiler) being used. Only when that
+test succeeds is it valid to use ``__has_include`` as a preprocessor
+operator. As a result, combining the two tests into a single expression
+as shown below would only be valid with a compiler that supports the operator
+but not with others that don't.
+
+.. code-block:: c++
+
+ #if defined __has_include && __has_include ("header.h") /* not portable */
+ ...
+ #endif
\ No newline at end of file
diff --git a/gcc/doc/cpp/conditional-uses.rst b/gcc/doc/cpp/conditional-uses.rst
new file mode 100644
index 00000000000..0418a9af710
--- /dev/null
+++ b/gcc/doc/cpp/conditional-uses.rst
@@ -0,0 +1,32 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _conditional-uses:
+
+Conditional Uses
+****************
+
+There are three general reasons to use a conditional.
+
+* A program may need to use different code depending on the machine or
+ operating system it is to run on. In some cases the code for one
+ operating system may be erroneous on another operating system; for
+ example, it might refer to data types or constants that do not exist on
+ the other system. When this happens, it is not enough to avoid
+ executing the invalid code. Its mere presence will cause the compiler
+ to reject the program. With a preprocessing conditional, the offending
+ code can be effectively excised from the program when it is not valid.
+
+* You may want to be able to compile the same source file into two
+ different programs. One version might make frequent time-consuming
+ consistency checks on its intermediate data, or print the values of
+ those data for debugging, and the other not.
+
+* A conditional whose condition is always false is one way to exclude code
+ from the program but keep it as a sort of comment for future reference.
+
+Simple programs that do not need system-specific logic or complex
+debugging hooks generally will not need to use preprocessing
+conditionals.
\ No newline at end of file
diff --git a/gcc/doc/cpp/conditionals.rst b/gcc/doc/cpp/conditionals.rst
new file mode 100644
index 00000000000..4ef20544394
--- /dev/null
+++ b/gcc/doc/cpp/conditionals.rst
@@ -0,0 +1,44 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _conditionals:
+
+Conditionals
+------------
+
+.. index:: conditionals
+
+A :dfn:`conditional` is a directive that instructs the preprocessor to
+select whether or not to include a chunk of code in the final token
+stream passed to the compiler. Preprocessor conditionals can test
+arithmetic expressions, or whether a name is defined as a macro, or both
+simultaneously using the special ``defined`` operator.
+
+A conditional in the C preprocessor resembles in some ways an ``if``
+statement in C, but it is important to understand the difference between
+them. The condition in an ``if`` statement is tested during the
+execution of your program. Its purpose is to allow your program to
+behave differently from run to run, depending on the data it is
+operating on. The condition in a preprocessing conditional directive is
+tested when your program is compiled. Its purpose is to allow different
+code to be included in the program depending on the situation at the
+time of compilation.
+
+However, the distinction is becoming less clear. Modern compilers often
+do test ``if`` statements when a program is compiled, if their
+conditions are known not to vary at run time, and eliminate code which
+can never be executed. If you can count on your compiler to do this,
+you may find that your program is more readable if you use ``if``
+statements with constant conditions (perhaps determined by macros). Of
+course, you can only use this to exclude code, not type definitions or
+other preprocessing directives, and you can only do it if the code
+remains syntactically valid when it is not to be used.
+
+.. toctree::
+ :maxdepth: 2
+
+ conditional-uses
+ conditional-syntax
+ deleted-code
\ No newline at end of file
diff --git a/gcc/doc/cpp/conf.py b/gcc/doc/cpp/conf.py
new file mode 100644
index 00000000000..2363a677b49
--- /dev/null
+++ b/gcc/doc/cpp/conf.py
@@ -0,0 +1,29 @@
+# Configuration file for the Sphinx documentation builder.
+
+import sys
+sys.path.append('../../..//doc')
+
+from baseconf import *
+
+project = 'The C Preprocessor'
+copyright = '1987-2021 Free Software Foundation, Inc.'
+authors = 'Richard M. Stallman, Zachary Weinberg'
+
+# Grouping the document tree into Texinfo files. List of tuples
+# (source start file, target name, title, author,
+# dir menu entry, description, category)
+latex_documents = [
+ ('index', 'cpp.tex', project, authors, 'manual'),
+]
+
+# One entry per manual page. List of tuples
+# (source start file, name, description, authors, manual section).
+man_pages = [
+ ('invocation', 'cpp', project, [authors], 1),
+]
+
+texinfo_documents = [
+ ('index', 'cpp', project, authors, None, None, None, True)
+]
+
+tags.add('cpp')
\ No newline at end of file
diff --git a/gcc/doc/cpp/copyright.rst b/gcc/doc/cpp/copyright.rst
new file mode 100644
index 00000000000..8e6b42353d3
--- /dev/null
+++ b/gcc/doc/cpp/copyright.rst
@@ -0,0 +1 @@
+.. include:: ../../../doc/copyright.rst
\ No newline at end of file
diff --git a/gcc/doc/cpp/deleted-code.rst b/gcc/doc/cpp/deleted-code.rst
new file mode 100644
index 00000000000..53340ccd672
--- /dev/null
+++ b/gcc/doc/cpp/deleted-code.rst
@@ -0,0 +1,34 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _deleted-code:
+
+Deleted Code
+************
+
+.. index:: commenting out code
+
+If you replace or delete a part of the program but want to keep the old
+code around for future reference, you often cannot simply comment it
+out. Block comments do not nest, so the first comment inside the old
+code will end the commenting-out. The probable result is a flood of
+syntax errors.
+
+One way to avoid this problem is to use an always-false conditional
+instead. For instance, put ``#if 0`` before the deleted code and
+``#endif`` after it. This works even if the code being turned
+off contains conditionals, but they must be entire conditionals
+(balanced :samp:`#if` and :samp:`#endif`).
+
+Some people use ``#ifdef notdef`` instead. This is risky, because
+``notdef`` might be accidentally defined as a macro, and then the
+conditional would succeed. ``#if 0`` can be counted on to fail.
+
+Do not use ``#if 0`` for comments which are not C code. Use a real
+comment, instead. The interior of ``#if 0`` must consist of complete
+tokens; in particular, single-quote characters must balance. Comments
+often contain unbalanced single-quote characters (known in English as
+apostrophes). These confuse ``#if 0``. They don't confuse
+:samp:`/*`.
\ No newline at end of file
diff --git a/gcc/doc/cpp/diagnostics.rst b/gcc/doc/cpp/diagnostics.rst
new file mode 100644
index 00000000000..092d31796e1
--- /dev/null
+++ b/gcc/doc/cpp/diagnostics.rst
@@ -0,0 +1,57 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _diagnostics:
+
+Diagnostics
+-----------
+
+.. index:: diagnostic
+
+.. index:: reporting errors
+
+.. index:: reporting warnings
+
+.. index:: #error
+
+The directive :samp:`#error` causes the preprocessor to report a fatal
+error. The tokens forming the rest of the line following :samp:`#error`
+are used as the error message.
+
+You would use :samp:`#error` inside of a conditional that detects a
+combination of parameters which you know the program does not properly
+support. For example, if you know that the program will not run
+properly on a VAX, you might write
+
+.. code-block:: c++
+
+ #ifdef __vax__
+ #error "Won't work on VAXen. See comments at get_last_object."
+ #endif
+
+If you have several configuration parameters that must be set up by
+the installation in a consistent way, you can use conditionals to detect
+an inconsistency and report it with :samp:`#error`. For example,
+
+.. code-block:: c++
+
+ #if !defined(FOO) && defined(BAR)
+ #error "BAR requires FOO."
+ #endif
+
+.. index:: #warning
+
+The directive :samp:`#warning` is like :samp:`#error`, but causes the
+preprocessor to issue a warning and continue preprocessing. The tokens
+following :samp:`#warning` are used as the warning message.
+
+You might use :samp:`#warning` in obsolete header files, with a message
+directing the user to the header file which should be used instead.
+
+Neither :samp:`#error` nor :samp:`#warning` macro-expands its argument.
+Internal whitespace sequences are each replaced with a single space.
+The line must consist of complete tokens. It is wisest to make the
+argument of these directives be a single string constant; this avoids
+problems with apostrophes and the like.
\ No newline at end of file
diff --git a/gcc/doc/cpp/environment-variables.rst b/gcc/doc/cpp/environment-variables.rst
new file mode 100644
index 00000000000..7c8a60df259
--- /dev/null
+++ b/gcc/doc/cpp/environment-variables.rst
@@ -0,0 +1,26 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _environment-variables:
+
+Environment Variables
+---------------------
+
+.. index:: environment variables
+
+This section describes the environment variables that affect how CPP
+operates. You can use them to specify directories or prefixes to use
+when searching for include files, or to control dependency output.
+
+Note that you can also specify places to search using options such as
+:option:`-I`, and control dependency output with options like
+:option:`-M` (see :ref:`invocation`). These take precedence over
+environment variables, which in turn take precedence over the
+configuration of GCC.
+
+.. include:: ../../../doc/cppenv.rst
+
+
+.. Special handling for inclusion in the install manual.
\ No newline at end of file
diff --git a/gcc/doc/cpp/gnu-free-documentation-license.rst b/gcc/doc/cpp/gnu-free-documentation-license.rst
new file mode 100644
index 00000000000..a9f00f268fa
--- /dev/null
+++ b/gcc/doc/cpp/gnu-free-documentation-license.rst
@@ -0,0 +1,6 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. include:: ../../../doc/gnu_free_documentation_license.rst
\ No newline at end of file
--git a/gcc/doc/cpp/header-files.rst b/gcc/doc/cpp/header-files.rst
new file mode 100644
index 00000000000..8583233f800
--- /dev/null
+++ b/gcc/doc/cpp/header-files.rst
@@ -0,0 +1,57 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _header-files:
+
+Header Files
+------------
+
+.. index:: header file
+
+A header file is a file containing C declarations and macro definitions
+(see :ref:`macros`) to be shared between several source files. You request
+the use of a header file in your program by :dfn:`including` it, with the
+C preprocessing directive :samp:`#include`.
+
+Header files serve two purposes.
+
+*
+ .. index:: system header files
+
+ System header files declare the interfaces to parts of the operating
+ system. You include them in your program to supply the definitions and
+ declarations you need to invoke system calls and libraries.
+
+* Your own header files contain declarations for interfaces between the
+ source files of your program. Each time you have a group of related
+ declarations and macro definitions all or most of which are needed in
+ several different source files, it is a good idea to create a header
+ file for them.
+
+Including a header file produces the same results as copying the header
+file into each source file that needs it. Such copying would be
+time-consuming and error-prone. With a header file, the related
+declarations appear in only one place. If they need to be changed, they
+can be changed in one place, and programs that include the header file
+will automatically use the new version when next recompiled. The header
+file eliminates the labor of finding and changing all the copies as well
+as the risk that a failure to find one copy will result in
+inconsistencies within a program.
+
+In C, the usual convention is to give header files names that end with
+:samp:`.h`. It is most portable to use only letters, digits, dashes, and
+underscores in header file names, and at most one dot.
+
+.. toctree::
+ :maxdepth: 2
+
+ header-files/include-syntax
+ header-files/include-operation
+ header-files/search-path
+ header-files/once-only-headers
+ header-files/alternatives-to-wrapper-#ifndef
+ header-files/computed-includes
+ header-files/wrapper-headers
+ header-files/system-headers
\ No newline at end of file
diff --git a/gcc/doc/cpp/header-files/alternatives-to-wrapper-#ifndef.rst b/gcc/doc/cpp/header-files/alternatives-to-wrapper-#ifndef.rst
new file mode 100644
index 00000000000..1674ba6f018
--- /dev/null
+++ b/gcc/doc/cpp/header-files/alternatives-to-wrapper-#ifndef.rst
@@ -0,0 +1,40 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _alternatives-to-wrapper-#ifndef:
+
+Alternatives to Wrapper #ifndef
+*******************************
+
+CPP supports two more ways of indicating that a header file should be
+read only once. Neither one is as portable as a wrapper :samp:`#ifndef`
+and we recommend you do not use them in new programs, with the caveat
+that :samp:`#import` is standard practice in Objective-C.
+
+.. index:: #import
+
+CPP supports a variant of :samp:`#include` called :samp:`#import` which
+includes a file, but does so at most once. If you use :samp:`#import`
+instead of :samp:`#include`, then you don't need the conditionals
+inside the header file to prevent multiple inclusion of the contents.
+:samp:`#import` is standard in Objective-C, but is considered a
+deprecated extension in C and C++.
+
+:samp:`#import` is not a well designed feature. It requires the users of
+a header file to know that it should only be included once. It is much
+better for the header file's implementor to write the file so that users
+don't need to know this. Using a wrapper :samp:`#ifndef` accomplishes
+this goal.
+
+In the present implementation, a single use of :samp:`#import` will
+prevent the file from ever being read again, by either :samp:`#import` or
+:samp:`#include`. You should not rely on this; do not use both
+:samp:`#import` and :samp:`#include` to refer to the same header file.
+
+Another way to prevent a header file from being included more than once
+is with the :samp:`#pragma once` directive (see :ref:`pragmas`).
+:samp:`#pragma once` does not have the problems that :samp:`#import` does,
+but it is not recognized by all preprocessors, so you cannot rely on it
+in a portable program.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/computed-includes.rst b/gcc/doc/cpp/header-files/computed-includes.rst
new file mode 100644
index 00000000000..cf4a2b67b0b
--- /dev/null
+++ b/gcc/doc/cpp/header-files/computed-includes.rst
@@ -0,0 +1,88 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _computed-includes:
+
+Computed Includes
+*****************
+
+.. index:: computed includes
+
+.. index:: macros in include
+
+Sometimes it is necessary to select one of several different header
+files to be included into your program. They might specify
+configuration parameters to be used on different sorts of operating
+systems, for instance. You could do this with a series of conditionals,
+
+.. code-block:: c++
+
+ #if SYSTEM_1
+ # include "system_1.h"
+ #elif SYSTEM_2
+ # include "system_2.h"
+ #elif SYSTEM_3
+ ...
+ #endif
+
+That rapidly becomes tedious. Instead, the preprocessor offers the
+ability to use a macro for the header name. This is called a
+:dfn:`computed include`. Instead of writing a header name as the direct
+argument of :samp:`#include`, you simply put a macro name there instead:
+
+.. code-block:: c++
+
+ #define SYSTEM_H "system_1.h"
+ ...
+ #include SYSTEM_H
+
+``SYSTEM_H`` will be expanded, and the preprocessor will look for
+:samp:`system_1.h` as if the :samp:`#include` had been written that way
+originally. ``SYSTEM_H`` could be defined by your Makefile with a
+:option:`-D` option.
+
+You must be careful when you define the macro. :samp:`#define` saves
+tokens, not text. The preprocessor has no way of knowing that the macro
+will be used as the argument of :samp:`#include`, so it generates
+ordinary tokens, not a header name. This is unlikely to cause problems
+if you use double-quote includes, which are close enough to string
+constants. If you use angle brackets, however, you may have trouble.
+
+The syntax of a computed include is actually a bit more general than the
+above. If the first non-whitespace character after :samp:`#include` is
+not :samp:`"` or :samp:`<`, then the entire line is macro-expanded
+like running text would be.
+
+If the line expands to a single string constant, the contents of that
+string constant are the file to be included. CPP does not re-examine the
+string for embedded quotes, but neither does it process backslash
+escapes in the string. Therefore
+
+.. code-block:: c++
+
+ #define HEADER "a\"b"
+ #include HEADER
+
+looks for a file named :samp:`a\\"b`. CPP searches for the file according
+to the rules for double-quoted includes.
+
+If the line expands to a token stream beginning with a :samp:`<` token
+and including a :samp:`>` token, then the tokens between the :samp:`<` and
+the first :samp:`>` are combined to form the filename to be included.
+Any whitespace between tokens is reduced to a single space; then any
+space after the initial :samp:`<` is retained, but a trailing space
+before the closing :samp:`>` is ignored. CPP searches for the file
+according to the rules for angle-bracket includes.
+
+In either case, if there are any tokens on the line after the file name,
+an error occurs and the directive is not processed. It is also an error
+if the result of expansion does not match either of the two expected
+forms.
+
+These rules are implementation-defined behavior according to the C
+standard. To minimize the risk of different compilers interpreting your
+computed includes differently, we recommend you use only a single
+object-like macro which expands to a string constant. This will also
+minimize confusion for people reading your program.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/include-operation.rst b/gcc/doc/cpp/header-files/include-operation.rst
new file mode 100644
index 00000000000..966dfcb28ab
--- /dev/null
+++ b/gcc/doc/cpp/header-files/include-operation.rst
@@ -0,0 +1,67 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _include-operation:
+
+Include Operation
+*****************
+
+The :samp:`#include` directive works by directing the C preprocessor to
+scan the specified file as input before continuing with the rest of the
+current file. The output from the preprocessor contains the output
+already generated, followed by the output resulting from the included
+file, followed by the output that comes from the text after the
+:samp:`#include` directive. For example, if you have a header file
+:samp:`header.h` as follows,
+
+.. code-block:: c++
+
+ char *test (void);
+
+and a main program called :samp:`program.c` that uses the header file,
+like this,
+
+.. code-block:: c++
+
+ int x;
+ #include "header.h"
+
+ int
+ main (void)
+ {
+ puts (test ());
+ }
+
+the compiler will see the same token stream as it would if
+:samp:`program.c` read
+
+.. code-block:: c++
+
+ int x;
+ char *test (void);
+
+ int
+ main (void)
+ {
+ puts (test ());
+ }
+
+Included files are not limited to declarations and macro definitions;
+those are merely the typical uses. Any fragment of a C program can be
+included from another file. The include file could even contain the
+beginning of a statement that is concluded in the containing file, or
+the end of a statement that was started in the including file. However,
+an included file must consist of complete tokens. Comments and string
+literals which have not been closed by the end of an included file are
+invalid. For error recovery, they are considered to end at the end of
+the file.
+
+To avoid confusion, it is best if header files contain only complete
+syntactic units---function declarations or definitions, type
+declarations, etc.
+
+The line following the :samp:`#include` directive is always treated as a
+separate line by the C preprocessor, even if the included file lacks a
+final newline.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/include-syntax.rst b/gcc/doc/cpp/header-files/include-syntax.rst
new file mode 100644
index 00000000000..757dace51ea
--- /dev/null
+++ b/gcc/doc/cpp/header-files/include-syntax.rst
@@ -0,0 +1,42 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _include-syntax:
+
+Include Syntax
+**************
+
+.. index:: #include
+
+Both user and system header files are included using the preprocessing
+directive :samp:`#include`. It has two variants:
+
+:samp:`#include <{file}>`
+ This variant is used for system header files. It searches for a file
+ named :samp:`{file}` in a standard list of system directories. You can prepend
+ directories to this list with the :option:`-I` option (see :ref:`invocation`).
+
+:samp:`#include "{file}"`
+ This variant is used for header files of your own program. It
+ searches for a file named :samp:`{file}` first in the directory containing
+ the current file, then in the quote directories and then the same
+ directories used for ``<file>``. You can prepend directories
+ to the list of quote directories with the :option:`-iquote` option.
+
+The argument of :samp:`#include`, whether delimited with quote marks or
+angle brackets, behaves like a string constant in that comments are not
+recognized, and macro names are not expanded. Thus, ``#include
+<x/*y>`` specifies inclusion of a system header file named :samp:`x/*y`.
+
+However, if backslashes occur within :samp:`{file}`, they are considered
+ordinary text characters, not escape characters. None of the character
+escape sequences appropriate to string constants in C are processed.
+Thus, ``#include "x\n\\y"`` specifies a filename containing three
+backslashes. (Some systems interpret :samp:`\\` as a pathname separator.
+All of these also interpret :samp:`/` the same way. It is most portable
+to use only :samp:`/`.)
+
+It is an error if there is anything (other than comments) on the line
+after the file name.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/once-only-headers.rst b/gcc/doc/cpp/header-files/once-only-headers.rst
new file mode 100644
index 00000000000..aa6ee950320
--- /dev/null
+++ b/gcc/doc/cpp/header-files/once-only-headers.rst
@@ -0,0 +1,58 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _once-only-headers:
+
+Once-Only Headers
+*****************
+
+.. index:: repeated inclusion
+
+.. index:: including just once
+
+.. index:: wrapper #ifndef
+
+If a header file happens to be included twice, the compiler will process
+its contents twice. This is very likely to cause an error, e.g. when the
+compiler sees the same structure definition twice. Even if it does not,
+it will certainly waste time.
+
+The standard way to prevent this is to enclose the entire real contents
+of the file in a conditional, like this:
+
+.. code-block:: c++
+
+ /* File foo. */
+ #ifndef FILE_FOO_SEEN
+ #define FILE_FOO_SEEN
+
+ the entire file
+
+ #endif /* !FILE_FOO_SEEN */
+
+This construct is commonly known as a :dfn:`wrapper #ifndef`.
+When the header is included again, the conditional will be false,
+because ``FILE_FOO_SEEN`` is defined. The preprocessor will skip
+over the entire contents of the file, and the compiler will not see it
+twice.
+
+CPP optimizes even further. It remembers when a header file has a
+wrapper :samp:`#ifndef`. If a subsequent :samp:`#include` specifies that
+header, and the macro in the :samp:`#ifndef` is still defined, it does
+not bother to rescan the file at all.
+
+You can put comments outside the wrapper. They will not interfere with
+this optimization.
+
+.. index:: controlling macro
+
+.. index:: guard macro
+
+The macro ``FILE_FOO_SEEN`` is called the :dfn:`controlling macro` or
+:dfn:`guard macro`. In a user header file, the macro name should not
+begin with :samp:`_`. In a system header file, it should begin with
+:samp:`__` to avoid conflicts with user programs. In any kind of header
+file, the macro name should contain the name of the file and some
+additional text, to avoid conflicts with other header files.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/search-path.rst b/gcc/doc/cpp/header-files/search-path.rst
new file mode 100644
index 00000000000..d421235e6a8
--- /dev/null
+++ b/gcc/doc/cpp/header-files/search-path.rst
@@ -0,0 +1,53 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _search-path:
+
+Search Path
+***********
+
+By default, the preprocessor looks for header files included by the quote
+form of the directive ``#include "file"`` first relative to
+the directory of the current file, and then in a preconfigured list
+of standard system directories.
+For example, if :samp:`/usr/include/sys/stat.h` contains
+``#include "types.h"``, GCC looks for :samp:`types.h` first in
+:samp:`/usr/include/sys`, then in its usual search path.
+
+For the angle-bracket form ``#include <file>``, the
+preprocessor's default behavior is to look only in the standard system
+directories. The exact search directory list depends on the target
+system, how GCC is configured, and where it is installed. You can
+find the default search directory list for your version of CPP by
+invoking it with the :option:`-v` option. For example,
+
+.. code-block:: c++
+
+ cpp -v /dev/null -o /dev/null
+
+There are a number of command-line options you can use to add
+additional directories to the search path.
+The most commonly-used option is :option:`-I`:samp:`{dir}`, which causes
+:samp:`{dir}` to be searched after the current directory (for the quote
+form of the directive) and ahead of the standard system directories.
+You can specify multiple :option:`-I` options on the command line,
+in which case the directories are searched in left-to-right order.
+
+If you need separate control over the search paths for the quote and
+angle-bracket forms of the :samp:`#include` directive, you can use the
+:option:`-iquote` and/or :option:`-isystem` options instead of :option:`-I`.
+See :ref:`invocation`, for a detailed description of these options, as
+well as others that are less generally useful.
+
+If you specify other options on the command line, such as :option:`-I`,
+that affect where the preprocessor searches for header files, the
+directory list printed by the :option:`-v` option reflects the actual
+search path used by the preprocessor.
+
+Note that you can also prevent the preprocessor from searching any of
+the default system header directories with the :option:`-nostdinc`
+option. This is useful when you are compiling an operating system
+kernel or some other program that does not use the standard C library
+facilities, or the standard C library itself.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/system-headers.rst b/gcc/doc/cpp/header-files/system-headers.rst
new file mode 100644
index 00000000000..b5475471eaf
--- /dev/null
+++ b/gcc/doc/cpp/header-files/system-headers.rst
@@ -0,0 +1,41 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _system-headers:
+
+System Headers
+**************
+
+.. index:: system header files
+
+The header files declaring interfaces to the operating system and
+runtime libraries often cannot be written in strictly conforming C.
+Therefore, GCC gives code found in :dfn:`system headers` special
+treatment. All warnings, other than those generated by :samp:`#warning`
+(see :ref:`diagnostics`), are suppressed while GCC is processing a system
+header. Macros defined in a system header are immune to a few warnings
+wherever they are expanded. This immunity is granted on an ad-hoc
+basis, when we find that a warning generates lots of false positives
+because of code in macros defined in system headers.
+
+Normally, only the headers found in specific directories are considered
+system headers. These directories are determined when GCC is compiled.
+There are, however, two ways to make normal headers into system headers:
+
+* Header files found in directories added to the search path with the
+ :option:`-isystem` and :option:`-idirafter` command-line options are
+ treated as system headers for the purposes of diagnostics.
+
+*
+ .. index:: #pragma GCC system_header
+
+ There is also a directive, ``#pragma GCC system_header``, which
+ tells GCC to consider the rest of the current include file a system
+ header, no matter where it was found. Code that comes before the
+ :samp:`#pragma` in the file is not affected. ``#pragma GCC
+ system_header`` has no effect in the primary source file.
+
+On some targets, such as RS/6000 AIX, GCC implicitly surrounds all
+system headers with an :samp:`extern "C"` block when compiling as C++.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/wrapper-headers.rst b/gcc/doc/cpp/header-files/wrapper-headers.rst
new file mode 100644
index 00000000000..7ccd8725576
--- /dev/null
+++ b/gcc/doc/cpp/header-files/wrapper-headers.rst
@@ -0,0 +1,62 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _wrapper-headers:
+
+Wrapper Headers
+***************
+
+.. index:: wrapper headers
+
+.. index:: overriding a header file
+
+.. index:: #include_next
+
+Sometimes it is necessary to adjust the contents of a system-provided
+header file without editing it directly. GCC's :command:`fixincludes`
+operation does this, for example. One way to do that would be to create
+a new header file with the same name and insert it in the search path
+before the original header. That works fine as long as you're willing
+to replace the old header entirely. But what if you want to refer to
+the old header from the new one?
+
+You cannot simply include the old header with :samp:`#include`. That
+will start from the beginning, and find your new header again. If your
+header is not protected from multiple inclusion (see :ref:`once-only-headers`), it will recurse infinitely and cause a fatal error.
+
+You could include the old header with an absolute pathname:
+
+.. code-block:: c++
+
+ #include "/usr/include/old-header.h"
+
+This works, but is not clean; should the system headers ever move, you
+would have to edit the new headers to match.
+
+There is no way to solve this problem within the C standard, but you can
+use the GNU extension :samp:`#include_next`. It means, 'Include the
+*next* file with this name'. This directive works like
+:samp:`#include` except in searching for the specified file: it starts
+searching the list of header file directories *after* the directory
+in which the current file was found.
+
+Suppose you specify :option:`-I /usr/local/include`, and the list of
+directories to search also includes :samp:`/usr/include`; and suppose
+both directories contain :samp:`signal.h`. Ordinary ``#include
+<signal.h>`` finds the file under :samp:`/usr/local/include`. If that
+file contains ``#include_next <signal.h>``, it starts searching
+after that directory, and finds the file in :samp:`/usr/include`.
+
+:samp:`#include_next` does not distinguish between ``<file>``
+and ``"file"`` inclusion, nor does it check that the file you
+specify has the same name as the current file. It simply looks for the
+file named, starting with the directory in the search path after the one
+where the current file was found.
+
+The use of :samp:`#include_next` can lead to great confusion. We
+recommend it be used only when there is no other alternative. In
+particular, it should not be used in the headers belonging to a specific
+program; it should be used only to make global corrections along the
+lines of :command:`fixincludes`.
\ No newline at end of file
diff --git a/gcc/doc/cpp/implementation-defined-behavior.rst b/gcc/doc/cpp/implementation-defined-behavior.rst
new file mode 100644
index 00000000000..f45530c960f
--- /dev/null
+++ b/gcc/doc/cpp/implementation-defined-behavior.rst
@@ -0,0 +1,99 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _implementation-defined-behavior:
+
+Implementation-defined behavior
+*******************************
+
+.. index:: implementation-defined behavior
+
+This is how CPP behaves in all the cases which the C standard
+describes as :dfn:`implementation-defined`. This term means that the
+implementation is free to do what it likes, but must document its choice
+and stick to it.
+
+.. FIXME: Check the C++ standard for more implementation-defined stuff.
+
+* The mapping of physical source file multi-byte characters to the
+ execution character set.
+
+ The input character set can be specified using the
+ :option:`-finput-charset` option, while the execution character set may
+ be controlled using the :option:`-fexec-charset` and
+ :option:`-fwide-exec-charset` options.
+
+* Identifier characters.
+
+.. _identifier-characters:
+
+ The C and C++ standards allow identifiers to be composed of :samp:`_`
+ and the alphanumeric characters. C++ also allows universal character
+ names. C99 and later C standards permit both universal character
+ names and implementation-defined characters. In both C and C++ modes,
+ GCC accepts in identifiers exactly those extended characters that
+ correspond to universal character names permitted by the chosen
+ standard.
+
+ GCC allows the :samp:`$` character in identifiers as an extension for
+ most targets. This is true regardless of the std = switch,
+ since this extension cannot conflict with standards-conforming
+ programs. When preprocessing assembler, however, dollars are not
+ identifier characters by default.
+
+ Currently the targets that by default do not permit :samp:`$` are AVR,
+ IP2K, MMIX, MIPS Irix 3, ARM aout, and PowerPC targets for the AIX
+ operating system.
+
+ You can override the default with :option:`-fdollars-in-identifiers` or
+ fno-dollars-in-identifiers. See :ref:`fdollars-in-identifiers`.
+
+* Non-empty sequences of whitespace characters.
+
+ In textual output, each whitespace sequence is collapsed to a single
+ space. For aesthetic reasons, the first token on each non-directive
+ line of output is preceded with sufficient spaces that it appears in the
+ same column as it did in the original source file.
+
+* The numeric value of character constants in preprocessor expressions.
+
+ The preprocessor and compiler interpret character constants in the
+ same way; i.e. escape sequences such as :samp:`\\a` are given the
+ values they would have on the target machine.
+
+ The compiler evaluates a multi-character character constant a character
+ at a time, shifting the previous value left by the number of bits per
+ target character, and then or-ing in the bit-pattern of the new
+ character truncated to the width of a target character. The final
+ bit-pattern is given type ``int``, and is therefore signed,
+ regardless of whether single characters are signed or not.
+ If there are more
+ characters in the constant than would fit in the target ``int`` the
+ compiler issues a warning, and the excess leading characters are
+ ignored.
+
+ For example, ``'ab'`` for a target with an 8-bit ``char`` would be
+ interpreted as :samp:`(int) ((unsigned char) 'a' * 256 + (unsigned char)
+ 'b')`, and ``'\234a'`` as :samp:`(int) ((unsigned char) '\\234' *
+ 256 + (unsigned char) 'a')`.
+
+* Source file inclusion.
+
+ For a discussion on how the preprocessor locates header files,
+ Include Operation.
+
+* Interpretation of the filename resulting from a macro-expanded
+ :samp:`#include` directive.
+
+ See :ref:`computed-includes`.
+
+* Treatment of a :samp:`#pragma` directive that after macro-expansion
+ results in a standard pragma.
+
+ No macro expansion occurs on any :samp:`#pragma` directive line, so the
+ question does not arise.
+
+ Note that GCC does not yet implement any of the standard
+ pragmas.
\ No newline at end of file
diff --git a/gcc/doc/cpp/implementation-details.rst b/gcc/doc/cpp/implementation-details.rst
new file mode 100644
index 00000000000..f5c3f2a1238
--- /dev/null
+++ b/gcc/doc/cpp/implementation-details.rst
@@ -0,0 +1,23 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _implementation-details:
+
+Implementation Details
+----------------------
+
+Here we document details of how the preprocessor's implementation
+affects its user-visible behavior. You should try to avoid undue
+reliance on behavior described here, as it is possible that it will
+change subtly in future implementations.
+
+Also documented here are obsolete features still supported by CPP.
+
+.. toctree::
+ :maxdepth: 2
+
+ implementation-defined-behavior
+ implementation-limits
+ obsolete-features
\ No newline at end of file
diff --git a/gcc/doc/cpp/implementation-limits.rst b/gcc/doc/cpp/implementation-limits.rst
new file mode 100644
index 00000000000..fedfcbdd1be
--- /dev/null
+++ b/gcc/doc/cpp/implementation-limits.rst
@@ -0,0 +1,68 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _implementation-limits:
+
+Implementation limits
+*********************
+
+.. index:: implementation limits
+
+CPP has a small number of internal limits. This section lists the
+limits which the C standard requires to be no lower than some minimum,
+and all the others known. It is intended that there should be as few limits
+as possible. If you encounter an undocumented or inconvenient limit,
+please report that as a bug. See :ref:`Reporting Bugs <bugs>`.
+
+Where we say something is limited :dfn:`only by available memory`, that
+means that internal data structures impose no intrinsic limit, and space
+is allocated with ``malloc`` or equivalent. The actual limit will
+therefore depend on many things, such as the size of other things
+allocated by the compiler at the same time, the amount of memory
+consumed by other processes on the same computer, etc.
+
+* Nesting levels of :samp:`#include` files.
+
+ We impose an arbitrary limit of 200 levels, to avoid runaway recursion.
+ The standard requires at least 15 levels.
+
+* Nesting levels of conditional inclusion.
+
+ The C standard mandates this be at least 63. CPP is limited only by
+ available memory.
+
+* Levels of parenthesized expressions within a full expression.
+
+ The C standard requires this to be at least 63. In preprocessor
+ conditional expressions, it is limited only by available memory.
+
+* Significant initial characters in an identifier or macro name.
+
+ The preprocessor treats all characters as significant. The C standard
+ requires only that the first 63 be significant.
+
+* Number of macros simultaneously defined in a single translation unit.
+
+ The standard requires at least 4095 be possible. CPP is limited only
+ by available memory.
+
+* Number of parameters in a macro definition and arguments in a macro call.
+
+ We allow ``USHRT_MAX``, which is no smaller than 65,535. The minimum
+ required by the standard is 127.
+
+* Number of characters on a logical source line.
+
+ The C standard requires a minimum of 4096 be permitted. CPP places
+ no limits on this, but you may get incorrect column numbers reported in
+ diagnostics for lines longer than 65,535 characters.
+
+* Maximum size of a source file.
+
+ The standard does not specify any lower limit on the maximum size of a
+ source file. GNU cpp maps files into memory, so it is limited by the
+ available address space. This is generally at least two gigabytes.
+ Depending on the operating system, the size of physical memory may or
+ may not be a limitation.
\ No newline at end of file
diff --git a/gcc/doc/cpp/index.rst b/gcc/doc/cpp/index.rst
new file mode 100644
index 00000000000..6896a4c8f26
--- /dev/null
+++ b/gcc/doc/cpp/index.rst
@@ -0,0 +1,34 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+Welcome to cpp documentation!
+===============================
+
+The C preprocessor implements the macro language used to transform C,
+C++, and Objective-C programs before they are compiled. It can also be
+useful on its own.
+
+Contents:
+
+.. toctree::
+ :maxdepth: 1
+
+ copyright
+ overview
+ header-files
+ macros
+ conditionals
+ diagnostics
+ line-control
+ pragmas
+ other-directives
+ preprocessor-output
+ traditional-mode
+ implementation-details
+ invocation
+ environment-variables
+ gnu-free-documentation-license
+
+ option-index
\ No newline at end of file
diff --git a/gcc/doc/cpp/initial-processing.rst b/gcc/doc/cpp/initial-processing.rst
new file mode 100644
index 00000000000..06e0532abf1
--- /dev/null
+++ b/gcc/doc/cpp/initial-processing.rst
@@ -0,0 +1,174 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _initial-processing:
+
+Initial processing
+******************
+
+The preprocessor performs a series of textual transformations on its
+input. These happen before all other processing. Conceptually, they
+happen in a rigid order, and the entire file is run through each
+transformation before the next one begins. CPP actually does them
+all at once, for performance reasons. These transformations correspond
+roughly to the first three 'phases of translation' described in the C
+standard.
+
+*
+ .. index:: line endings
+
+ The input file is read into memory and broken into lines.
+
+ Different systems use different conventions to indicate the end of a
+ line. GCC accepts the ASCII control sequences LF, CR
+ LF and CR as end-of-line markers. These are the canonical
+ sequences used by Unix, DOS and VMS, and the classic Mac OS (before
+ OSX) respectively. You may therefore safely copy source code written
+ on any of those systems to a different one and use it without
+ conversion. (GCC may lose track of the current line number if a file
+ doesn't consistently use one convention, as sometimes happens when it
+ is edited on computers with different conventions that share a network
+ file system.)
+
+ If the last line of any input file lacks an end-of-line marker, the end
+ of the file is considered to implicitly supply one. The C standard says
+ that this condition provokes undefined behavior, so GCC will emit a
+ warning message.
+
+*
+ .. index:: trigraphs
+
+ .. _trigraphs:
+
+ If trigraphs are enabled, they are replaced by their
+ corresponding single characters. By default GCC ignores trigraphs,
+ but if you request a strictly conforming mode with the :option:`-std`
+ option, or you specify the :option:`-trigraphs` option, then it
+ converts them.
+
+ These are nine three-character sequences, all starting with :samp:`??`,
+ that are defined by ISO C to stand for single characters. They permit
+ obsolete systems that lack some of C's punctuation to use C. For
+ example, :samp:`??/` stands for :samp:`\\`, so ``'??/n'`` is a character
+ constant for a newline.
+
+ Trigraphs are not popular and many compilers implement them
+ incorrectly. Portable code should not rely on trigraphs being either
+ converted or ignored. With :option:`-Wtrigraphs` GCC will warn you
+ when a trigraph may change the meaning of your program if it were
+ converted. See :ref:`wtrigraphs`.
+
+ In a string constant, you can prevent a sequence of question marks
+ from being confused with a trigraph by inserting a backslash between
+ the question marks, or by separating the string literal at the
+ trigraph and making use of string literal concatenation. ``"(??\?)"``
+ is the string :samp:`(???)`, not :samp:`(?]`. Traditional C compilers
+ do not recognize these idioms.
+
+ The nine trigraphs and their replacements are
+
+ .. code-block::
+
+ Trigraph: ??( ??) ??< ??> ??= ??/ ??' ??! ??-
+ Replacement: [ ] { } # \ ^ | ~
+
+*
+ .. index:: continued lines
+
+ .. index:: backslash-newline
+
+ Continued lines are merged into one long line.
+
+ A continued line is a line which ends with a backslash, :samp:`\\`. The
+ backslash is removed and the following line is joined with the current
+ one. No space is inserted, so you may split a line anywhere, even in
+ the middle of a word. (It is generally more readable to split lines
+ only at white space.)
+
+ The trailing backslash on a continued line is commonly referred to as a
+ :dfn:`backslash-newline`.
+
+ If there is white space between a backslash and the end of a line, that
+ is still a continued line. However, as this is usually the result of an
+ editing mistake, and many compilers will not accept it as a continued
+ line, GCC will warn you about it.
+
+*
+ .. index:: comments
+
+ .. index:: line comments
+
+ .. index:: block comments
+
+ All comments are replaced with single spaces.
+
+ There are two kinds of comments. :dfn:`Block comments` begin with
+ :samp:`/*` and continue until the next :samp:`*/`. Block comments do not
+ nest:
+
+ .. code-block:: c++
+
+ /* this is /* one comment */ text outside comment
+
+ :dfn:`Line comments` begin with :samp:`//` and continue to the end of the
+ current line. Line comments do not nest either, but it does not matter,
+ because they would end in the same place anyway.
+
+ .. code-block:: c++
+
+ // this is // one comment
+ text outside comment
+
+It is safe to put line comments inside block comments, or vice versa.
+
+.. code-block:: c++
+
+ /* block comment
+ // contains line comment
+ yet more comment
+ */ outside comment
+
+ // line comment /* contains block comment */
+
+But beware of commenting out one end of a block comment with a line
+comment.
+
+.. code-block::
+
+ // l.c. /* block comment begins
+ oops! this isn't a comment anymore */
+
+Comments are not recognized within string literals.
+``"/* blah */"`` is the string constant :samp:`/\* blah \*/`, not
+an empty string.
+
+Line comments are not in the 1989 edition of the C standard, but they
+are recognized by GCC as an extension. In C++ and in the 1999 edition
+of the C standard, they are an official part of the language.
+
+Since these transformations happen before all other processing, you can
+split a line mechanically with backslash-newline anywhere. You can
+comment out the end of a line. You can continue a line comment onto the
+next line with backslash-newline. You can even split :samp:`/*`,
+:samp:`*/`, and :samp:`//` onto multiple lines with backslash-newline.
+For example:
+
+.. code-block::
+
+ /\
+ *
+ */ # /*
+ */ defi\
+ ne FO\
+ O 10\
+ 20
+
+is equivalent to ``#define FOO 1020``. All these tricks are
+extremely confusing and should not be used in code intended to be
+readable.
+
+There is no way to prevent a backslash at the end of a line from being
+interpreted as a backslash-newline. This cannot affect any correct
+program, however.
\ No newline at end of file
diff --git a/gcc/doc/cpp/invocation.rst b/gcc/doc/cpp/invocation.rst
new file mode 100644
index 00000000000..ce6400af8b0
--- /dev/null
+++ b/gcc/doc/cpp/invocation.rst
@@ -0,0 +1,85 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _invocation:
+
+Invocation
+----------
+
+.. index:: invocation
+
+.. index:: command line
+
+Most often when you use the C preprocessor you do not have to invoke it
+explicitly: the C compiler does so automatically. However, the
+preprocessor is sometimes useful on its own. You can invoke the
+preprocessor either with the :command:`cpp` command, or via :command:`gcc -E`.
+In GCC, the preprocessor is actually integrated with the compiler
+rather than a separate program, and both of these commands invoke
+GCC and tell it to stop after the preprocessing phase.
+
+The :command:`cpp` options listed here are also accepted by
+:command:`gcc` and have the same meaning. Likewise the :command:`cpp`
+command accepts all the usual :command:`gcc` driver options, although those
+pertaining to compilation phases after preprocessing are ignored.
+
+Only options specific to preprocessing behavior are documented here.
+Refer to the GCC manual for full documentation of other driver options.
+
+.. only:: man
+
+ Synopsis
+ ^^^^^^^^
+
+ cpp [ :option:`-D`:samp:`{macro}` [= :samp:`{defn}` ]...] [ :option:`-U`:samp:`{macro}` ]
+ [ :option:`-I`:samp:`{dir}`...] [ :option:`-iquote`:samp:`{dir}`...]
+ [ :option:`-M` | :option:`-MM` ] [ :option:`-MG` ] [ :option:`-MF` :samp:`{filename}` ]
+ [ :option:`-MP` ] [ :option:`-MQ` :samp:`{target}`...]
+ [ :option:`-MT` :samp:`{target}`...]
+ :samp:`{infile}` [[ :option:`-o` ] :samp:`{outfile}` ]
+
+ Only the most useful options are given above; see below for a more
+ complete list of preprocessor-specific options.
+ In addition, :command:`cpp` accepts most :command:`gcc` driver options, which
+ are not listed here. Refer to the GCC documentation for details.
+
+Options
+^^^^^^^
+
+The :command:`cpp` command expects two file names as arguments, :samp:`{infile}` and
+:samp:`{outfile}`. The preprocessor reads :samp:`{infile}` together with any
+other files it specifies with :samp:`#include`. All the output generated
+by the combined input files is written in :samp:`{outfile}`.
+
+Either :samp:`{infile}` or :samp:`{outfile}` may be :option:`-`, which as
+:samp:`{infile}` means to read from standard input and as :samp:`{outfile}`
+means to write to standard output. If either file is omitted, it
+means the same as if :option:`-` had been specified for that file.
+You can also use the :option:`-o` :samp:`{outfile}` option to specify the
+output file.
+
+Unless otherwise noted, or the option ends in :samp:`=`, all options
+which take an argument may have that argument appear either immediately
+after the option, or with a space between option and argument:
+:option:`-Ifoo` and :option:`-I foo` have the same effect.
+
+.. index:: grouping options
+
+.. index:: options, grouping
+
+Many options have multi-letter names; therefore multiple single-letter
+options may *not* be grouped: :option:`-dM` is very different from
+:samp:`-d -M`.
+
+.. index:: options
+
+.. include:: ../../../doc/cppopts.rst
+
+
+.. include:: ../../../doc/cppdiropts.rst
+
+.. only:: man
+
+ .. include:: ../../../doc/copyright.rst
\ No newline at end of file
diff --git a/gcc/doc/cpp/line-control.rst b/gcc/doc/cpp/line-control.rst
new file mode 100644
index 00000000000..dcd297391e2
--- /dev/null
+++ b/gcc/doc/cpp/line-control.rst
@@ -0,0 +1,55 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _line-control:
+
+Line Control
+------------
+
+.. index:: line control
+
+The C preprocessor informs the C compiler of the location in your source
+code where each token came from. Presently, this is just the file name
+and line number. All the tokens resulting from macro expansion are
+reported as having appeared on the line of the source file where the
+outermost macro was used. We intend to be more accurate in the future.
+
+If you write a program which generates source code, such as the
+:command:`bison` parser generator, you may want to adjust the preprocessor's
+notion of the current file name and line number by hand. Parts of the
+output from :command:`bison` are generated from scratch, other parts come
+from a standard parser file. The rest are copied verbatim from
+:command:`bison`'s input. You would like compiler error messages and
+symbolic debuggers to be able to refer to ``bison`` 's input file.
+
+.. index:: #line
+
+:command:`bison` or any such program can arrange this by writing
+:samp:`#line` directives into the output file. :samp:`#line` is a
+directive that specifies the original line number and source file name
+for subsequent input in the current preprocessor input file.
+:samp:`#line` has three variants:
+
+:samp:`#line {linenum}`
+ :samp:`{linenum}` is a non-negative decimal integer constant. It specifies
+ the line number which should be reported for the following line of
+ input. Subsequent lines are counted from :samp:`{linenum}`.
+
+:samp:`#line {linenum}{filename}`
+ :samp:`{linenum}` is the same as for the first form, and has the same
+ effect. In addition, :samp:`{filename}` is a string constant. The
+ following line and all subsequent lines are reported to come from the
+ file it specifies, until something else happens to change that.
+ :samp:`{filename}` is interpreted according to the normal rules for a string
+ constant: backslash escapes are interpreted. This is different from
+ :samp:`#include`.
+
+:samp:`#line {anything else}`
+ :samp:`{anything else}` is checked for macro calls, which are expanded.
+ The result should match one of the above two forms.
+
+:samp:`#line` directives alter the results of the ``__FILE__`` and
+``__LINE__`` predefined macros from that point on. See :ref:`standard-predefined-macros`. They do not have any effect on :samp:`#include`'s
+idea of the directory containing the current file.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros.rst b/gcc/doc/cpp/macros.rst
new file mode 100644
index 00000000000..ba259608a1d
--- /dev/null
+++ b/gcc/doc/cpp/macros.rst
@@ -0,0 +1,37 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _macros:
+
+Macros
+------
+
+A :dfn:`macro` is a fragment of code which has been given a name.
+Whenever the name is used, it is replaced by the contents of the macro.
+There are two kinds of macros. They differ mostly in what they look
+like when they are used. :dfn:`Object-like` macros resemble data objects
+when used, :dfn:`function-like` macros resemble function calls.
+
+You may define any valid identifier as a macro, even if it is a C
+keyword. The preprocessor does not know anything about keywords. This
+can be useful if you wish to hide a keyword such as ``const`` from an
+older compiler that does not understand it. However, the preprocessor
+operator ``defined`` (see :ref:`defined`) can never be defined as a
+macro, and C++'s named operators (see :ref:`c++-named-operators`) cannot be
+macros when you are compiling C++.
+
+.. toctree::
+ :maxdepth: 2
+
+ macros/object-like-macros
+ macros/function-like-macros
+ macros/macro-arguments
+ macros/stringizing
+ macros/concatenation
+ macros/variadic-macros
+ macros/predefined-macros
+ macros/undefining-and-redefining-macros
+ macros/directives-within-macro-arguments
+ macros/macro-pitfalls
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/concatenation.rst b/gcc/doc/cpp/macros/concatenation.rst
new file mode 100644
index 00000000000..1ba6cde247a
--- /dev/null
+++ b/gcc/doc/cpp/macros/concatenation.rst
@@ -0,0 +1,91 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _concatenation:
+
+Concatenation
+*************
+
+.. index:: concatenation
+
+.. index:: token pasting
+
+.. index:: token concatenation
+
+.. index:: ## operator
+
+It is often useful to merge two tokens into one while expanding macros.
+This is called :dfn:`token pasting` or :dfn:`token concatenation`. The
+:samp:`##` preprocessing operator performs token pasting. When a macro
+is expanded, the two tokens on either side of each :samp:`##` operator
+are combined into a single token, which then replaces the :samp:`##` and
+the two original tokens in the macro expansion. Usually both will be
+identifiers, or one will be an identifier and the other a preprocessing
+number. When pasted, they make a longer identifier. This isn't the
+only valid case. It is also possible to concatenate two numbers (or a
+number and a name, such as ``1.5`` and ``e3`` ) into a number.
+Also, multi-character operators such as ``+=`` can be formed by
+token pasting.
+
+However, two tokens that don't together form a valid token cannot be
+pasted together. For example, you cannot concatenate ``x`` with
+``+`` in either order. If you try, the preprocessor issues a warning
+and emits the two tokens. Whether it puts white space between the
+tokens is undefined. It is common to find unnecessary uses of :samp:`##`
+in complex macros. If you get this warning, it is likely that you can
+simply remove the :samp:`##`.
+
+Both the tokens combined by :samp:`##` could come from the macro body,
+but you could just as well write them as one token in the first place.
+Token pasting is most useful when one or both of the tokens comes from a
+macro argument. If either of the tokens next to an :samp:`##` is a
+parameter name, it is replaced by its actual argument before :samp:`##`
+executes. As with stringizing, the actual argument is not
+macro-expanded first. If the argument is empty, that :samp:`##` has no
+effect.
+
+Keep in mind that the C preprocessor converts comments to whitespace
+before macros are even considered. Therefore, you cannot create a
+comment by concatenating :samp:`/` and :samp:`*`. You can put as much
+whitespace between :samp:`##` and its operands as you like, including
+comments, and you can put comments in arguments that will be
+concatenated. However, it is an error if :samp:`##` appears at either
+end of a macro body.
+
+Consider a C program that interprets named commands. There probably
+needs to be a table of commands, perhaps an array of structures declared
+as follows:
+
+.. code-block:: c++
+
+ struct command
+ {
+ char *name;
+ void (*function) (void);
+ };
+
+ struct command commands[] =
+ {
+ { "quit", quit_command },
+ { "help", help_command },
+ ...
+ };
+
+It would be cleaner not to have to give each command name twice, once in
+the string constant and once in the function name. A macro which takes the
+name of a command as an argument can make this unnecessary. The string
+constant can be created with stringizing, and the function name by
+concatenating the argument with :samp:`_command`. Here is how it is done:
+
+.. code-block:: c++
+
+ #define COMMAND(NAME) { #NAME, NAME ## _command }
+
+ struct command commands[] =
+ {
+ COMMAND (quit),
+ COMMAND (help),
+ ...
+ };
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/directives-within-macro-arguments.rst b/gcc/doc/cpp/macros/directives-within-macro-arguments.rst
new file mode 100644
index 00000000000..5c8f1c6dfcd
--- /dev/null
+++ b/gcc/doc/cpp/macros/directives-within-macro-arguments.rst
@@ -0,0 +1,39 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _directives-within-macro-arguments:
+
+Directives Within Macro Arguments
+*********************************
+
+.. index:: macro arguments and directives
+
+Occasionally it is convenient to use preprocessor directives within
+the arguments of a macro. The C and C++ standards declare that
+behavior in these cases is undefined. GNU CPP
+processes arbitrary directives within macro arguments in
+exactly the same way as it would have processed the directive were the
+function-like macro invocation not present.
+
+If, within a macro invocation, that macro is redefined, then the new
+definition takes effect in time for argument pre-expansion, but the
+original definition is still used for argument replacement. Here is a
+pathological example:
+
+.. code-block:: c++
+
+ #define f(x) x x
+ f (1
+ #undef f
+ #define f 2
+ f)
+
+which expands to
+
+.. code-block:: c++
+
+ 1 2 1 2
+
+with the semantics described above.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/function-like-macros.rst b/gcc/doc/cpp/macros/function-like-macros.rst
new file mode 100644
index 00000000000..12273bda869
--- /dev/null
+++ b/gcc/doc/cpp/macros/function-like-macros.rst
@@ -0,0 +1,55 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _function-like-macros:
+
+Function-like Macros
+********************
+
+.. index:: function-like macros
+
+You can also define macros whose use looks like a function call. These
+are called :dfn:`function-like macros`. To define a function-like macro,
+you use the same :samp:`#define` directive, but you put a pair of
+parentheses immediately after the macro name. For example,
+
+.. code-block::
+
+ #define lang_init() c_init()
+ lang_init()
+ → c_init()
+
+A function-like macro is only expanded if its name appears with a pair
+of parentheses after it. If you write just the name, it is left alone.
+This can be useful when you have a function and a macro of the same
+name, and you wish to use the function sometimes.
+
+.. code-block::
+
+ extern void foo(void);
+ #define foo() /* optimized inline version */
+ ...
+ foo();
+ funcptr = foo;
+
+Here the call to ``foo()`` will use the macro, but the function
+pointer will get the address of the real function. If the macro were to
+be expanded, it would cause a syntax error.
+
+If you put spaces between the macro name and the parentheses in the
+macro definition, that does not define a function-like macro, it defines
+an object-like macro whose expansion happens to begin with a pair of
+parentheses.
+
+.. code-block::
+
+ #define lang_init () c_init()
+ lang_init()
+ → () c_init()()
+
+The first two pairs of parentheses in this expansion come from the
+macro. The third is the pair that was originally after the macro
+invocation. Since ``lang_init`` is an object-like macro, it does not
+consume those parentheses.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/macro-arguments.rst b/gcc/doc/cpp/macros/macro-arguments.rst
new file mode 100644
index 00000000000..c65dfa1e12a
--- /dev/null
+++ b/gcc/doc/cpp/macros/macro-arguments.rst
@@ -0,0 +1,116 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _macro-arguments:
+
+Macro Arguments
+***************
+
+.. index:: arguments
+
+.. index:: macros with arguments
+
+.. index:: arguments in macro definitions
+
+Function-like macros can take :dfn:`arguments`, just like true functions.
+To define a macro that uses arguments, you insert :dfn:`parameters`
+between the pair of parentheses in the macro definition that make the
+macro function-like. The parameters must be valid C identifiers,
+separated by commas and optionally whitespace.
+
+To invoke a macro that takes arguments, you write the name of the macro
+followed by a list of :dfn:`actual arguments` in parentheses, separated
+by commas. The invocation of the macro need not be restricted to a
+single logical line---it can cross as many lines in the source file as
+you wish. The number of arguments you give must match the number of
+parameters in the macro definition. When the macro is expanded, each
+use of a parameter in its body is replaced by the tokens of the
+corresponding argument. (You need not use all of the parameters in the
+macro body.)
+
+As an example, here is a macro that computes the minimum of two numeric
+values, as it is defined in many C programs, and some uses.
+
+.. code-block::
+
+ #define min(X, Y) ((X) < (Y) ? (X) : (Y))
+ x = min(a, b); → x = ((a) < (b) ? (a) : (b));
+ y = min(1, 2); → y = ((1) < (2) ? (1) : (2));
+ z = min(a + 28, *p); → z = ((a + 28) < (*p) ? (a + 28) : (*p));
+
+(In this small example you can already see several of the dangers of
+macro arguments. See :ref:`macro-pitfalls`, for detailed explanations.)
+
+Leading and trailing whitespace in each argument is dropped, and all
+whitespace between the tokens of an argument is reduced to a single
+space. Parentheses within each argument must balance; a comma within
+such parentheses does not end the argument. However, there is no
+requirement for square brackets or braces to balance, and they do not
+prevent a comma from separating arguments. Thus,
+
+.. code-block:: c++
+
+ macro (array[x = y, x + 1])
+
+passes two arguments to ``macro`` : ``array[x = y`` and ``x +
+1]``. If you want to supply ``array[x = y, x + 1]`` as an argument,
+you can write it as ``array[(x = y, x + 1)]``, which is equivalent C
+code.
+
+All arguments to a macro are completely macro-expanded before they are
+substituted into the macro body. After substitution, the complete text
+is scanned again for macros to expand, including the arguments. This rule
+may seem strange, but it is carefully designed so you need not worry
+about whether any function call is actually a macro invocation. You can
+run into trouble if you try to be too clever, though. See :ref:`argument-prescan`, for detailed discussion.
+
+For example, ``min (min (a, b), c)`` is first expanded to
+
+.. code-block:: c++
+
+ min (((a) < (b) ? (a) : (b)), (c))
+
+and then to
+
+.. code-block:: c++
+
+ ((((a) < (b) ? (a) : (b))) < (c)
+ ? (((a) < (b) ? (a) : (b)))
+ : (c))
+
+(Line breaks shown here for clarity would not actually be generated.)
+
+.. index:: empty macro arguments
+
+You can leave macro arguments empty; this is not an error to the
+preprocessor (but many macros will then expand to invalid code).
+You cannot leave out arguments entirely; if a macro takes two arguments,
+there must be exactly one comma at the top level of its argument list.
+Here are some silly examples using ``min`` :
+
+.. code-block::
+
+ min(, b) → (( ) < (b) ? ( ) : (b))
+ min(a, ) → ((a ) < ( ) ? (a ) : ( ))
+ min(,) → (( ) < ( ) ? ( ) : ( ))
+ min((,),) → (((,)) < ( ) ? ((,)) : ( ))
+
+ min() error macro "min" requires 2 arguments, but only 1 given
+ min(,,) error macro "min" passed 3 arguments, but takes just 2
+
+Whitespace is not a preprocessing token, so if a macro ``foo`` takes
+one argument, ``foo ()`` and ``foo ( )`` both supply it an
+empty argument. Previous GNU preprocessor implementations and
+documentation were incorrect on this point, insisting that a
+function-like macro that takes a single argument be passed a space if an
+empty argument was required.
+
+Macro parameters appearing inside string literals are not replaced by
+their corresponding actual arguments.
+
+.. code-block::
+
+ #define foo(x) x, "x"
+ foo(bar) → bar, "x"
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/macro-pitfalls.rst b/gcc/doc/cpp/macros/macro-pitfalls.rst
new file mode 100644
index 00000000000..ff3dbbd8610
--- /dev/null
+++ b/gcc/doc/cpp/macros/macro-pitfalls.rst
@@ -0,0 +1,457 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _macro-pitfalls:
+
+Macro Pitfalls
+**************
+
+.. index:: problems with macros
+
+.. index:: pitfalls of macros
+
+In this section we describe some special rules that apply to macros and
+macro expansion, and point out certain cases in which the rules have
+counter-intuitive consequences that you must watch out for.
+
+.. toctree::
+ :maxdepth: 2
+
+
+.. _misnesting:
+
+Misnesting
+^^^^^^^^^^
+
+When a macro is called with arguments, the arguments are substituted
+into the macro body and the result is checked, together with the rest of
+the input file, for more macro calls. It is possible to piece together
+a macro call coming partially from the macro body and partially from the
+arguments. For example,
+
+.. code-block::
+
+ #define twice(x) (2*(x))
+ #define call_with_1(x) x(1)
+ call_with_1 (twice)
+ → twice(1)
+ → (2*(1))
+
+Macro definitions do not have to have balanced parentheses. By writing
+an unbalanced open parenthesis in a macro body, it is possible to create
+a macro call that begins inside the macro body but ends outside of it.
+For example,
+
+.. code-block::
+
+ #define strange(file) fprintf (file, "%s %d",
+ ...
+ strange(stderr) p, 35)
+ → fprintf (stderr, "%s %d", p, 35)
+
+The ability to piece together a macro call can be useful, but the use of
+unbalanced open parentheses in a macro body is just confusing, and
+should be avoided.
+
+.. _operator-precedence-problems:
+
+Operator Precedence Problems
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: parentheses in macro bodies
+
+You may have noticed that in most of the macro definition examples shown
+above, each occurrence of a macro argument name had parentheses around
+it. In addition, another pair of parentheses usually surround the
+entire macro definition. Here is why it is best to write macros that
+way.
+
+Suppose you define a macro as follows,
+
+.. code-block:: c++
+
+ #define ceil_div(x, y) (x + y - 1) / y
+
+whose purpose is to divide, rounding up. (One use for this operation is
+to compute how many ``int`` objects are needed to hold a certain
+number of ``char`` objects.) Then suppose it is used as follows:
+
+.. code-block::
+
+ a = ceil_div (b & c, sizeof (int));
+ → a = (b & c + sizeof (int) - 1) / sizeof (int);
+
+This does not do what is intended. The operator-precedence rules of
+C make it equivalent to this:
+
+.. code-block:: c++
+
+ a = (b & (c + sizeof (int) - 1)) / sizeof (int);
+
+What we want is this:
+
+.. code-block:: c++
+
+ a = ((b & c) + sizeof (int) - 1)) / sizeof (int);
+
+Defining the macro as
+
+.. code-block:: c++
+
+ #define ceil_div(x, y) ((x) + (y) - 1) / (y)
+
+provides the desired result.
+
+Unintended grouping can result in another way. Consider ``sizeof
+ceil_div(1, 2)``. That has the appearance of a C expression that would
+compute the size of the type of ``ceil_div (1, 2)``, but in fact it
+means something very different. Here is what it expands to:
+
+.. code-block:: c++
+
+ sizeof ((1) + (2) - 1) / (2)
+
+This would take the size of an integer and divide it by two. The
+precedence rules have put the division outside the ``sizeof`` when it
+was intended to be inside.
+
+Parentheses around the entire macro definition prevent such problems.
+Here, then, is the recommended way to define ``ceil_div`` :
+
+.. code-block:: c++
+
+ #define ceil_div(x, y) (((x) + (y) - 1) / (y))
+
+.. _swallowing-the-semicolon:
+
+Swallowing the Semicolon
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: semicolons (after macro calls)
+
+Often it is desirable to define a macro that expands into a compound
+statement. Consider, for example, the following macro, that advances a
+pointer (the argument ``p`` says where to find it) across whitespace
+characters:
+
+.. code-block:: c++
+
+ #define SKIP_SPACES(p, limit) \
+ { char *lim = (limit); \
+ while (p < lim) { \
+ if (*p++ != ' ') { \
+ p--; break; }}}
+
+Here backslash-newline is used to split the macro definition, which must
+be a single logical line, so that it resembles the way such code would
+be laid out if not part of a macro definition.
+
+A call to this macro might be ``SKIP_SPACES (p, lim)``. Strictly
+speaking, the call expands to a compound statement, which is a complete
+statement with no need for a semicolon to end it. However, since it
+looks like a function call, it minimizes confusion if you can use it
+like a function call, writing a semicolon afterward, as in
+``SKIP_SPACES (p, lim);``
+
+This can cause trouble before ``else`` statements, because the
+semicolon is actually a null statement. Suppose you write
+
+.. code-block:: c++
+
+ if (*p != 0)
+ SKIP_SPACES (p, lim);
+ else ...
+
+The presence of two statements---the compound statement and a null
+statement---in between the ``if`` condition and the ``else``
+makes invalid C code.
+
+The definition of the macro ``SKIP_SPACES`` can be altered to solve
+this problem, using a ``do ... while`` statement. Here is how:
+
+.. code-block:: c++
+
+ #define SKIP_SPACES(p, limit) \
+ do { char *lim = (limit); \
+ while (p < lim) { \
+ if (*p++ != ' ') { \
+ p--; break; }}} \
+ while (0)
+
+Now ``SKIP_SPACES (p, lim);`` expands into
+
+.. code-block:: c++
+
+ do {...} while (0);
+
+which is one statement. The loop executes exactly once; most compilers
+generate no extra code for it.
+
+.. _duplication-of-side-effects:
+
+Duplication of Side Effects
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: side effects (in macro arguments)
+
+.. index:: unsafe macros
+
+Many C programs define a macro ``min``, for 'minimum', like this:
+
+.. code-block:: c++
+
+ #define min(X, Y) ((X) < (Y) ? (X) : (Y))
+
+When you use this macro with an argument containing a side effect,
+as shown here,
+
+.. code-block:: c++
+
+ next = min (x + y, foo (z));
+
+it expands as follows:
+
+.. code-block:: c++
+
+ next = ((x + y) < (foo (z)) ? (x + y) : (foo (z)));
+
+where ``x + y`` has been substituted for ``X`` and ``foo (z)``
+for ``Y``.
+
+The function ``foo`` is used only once in the statement as it appears
+in the program, but the expression ``foo (z)`` has been substituted
+twice into the macro expansion. As a result, ``foo`` might be called
+two times when the statement is executed. If it has side effects or if
+it takes a long time to compute, the results might not be what you
+intended. We say that ``min`` is an :dfn:`unsafe` macro.
+
+The best solution to this problem is to define ``min`` in a way that
+computes the value of ``foo (z)`` only once. The C language offers
+no standard way to do this, but it can be done with GNU extensions as
+follows:
+
+.. code-block:: c++
+
+ #define min(X, Y) \
+ ({ typeof (X) x_ = (X); \
+ typeof (Y) y_ = (Y); \
+ (x_ < y_) ? x_ : y_; })
+
+The :samp:`({ ... })` notation produces a compound statement that
+acts as an expression. Its value is the value of its last statement.
+This permits us to define local variables and assign each argument to
+one. The local variables have underscores after their names to reduce
+the risk of conflict with an identifier of wider scope (it is impossible
+to avoid this entirely). Now each argument is evaluated exactly once.
+
+If you do not wish to use GNU C extensions, the only solution is to be
+careful when *using* the macro ``min``. For example, you can
+calculate the value of ``foo (z)``, save it in a variable, and use
+that variable in ``min`` :
+
+.. code-block:: c++
+
+ #define min(X, Y) ((X) < (Y) ? (X) : (Y))
+ ...
+ {
+ int tem = foo (z);
+ next = min (x + y, tem);
+ }
+
+(where we assume that ``foo`` returns type ``int`` ).
+
+.. _self-referential-macros:
+
+Self-Referential Macros
+^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: self-reference
+
+A :dfn:`self-referential` macro is one whose name appears in its
+definition. Recall that all macro definitions are rescanned for more
+macros to replace. If the self-reference were considered a use of the
+macro, it would produce an infinitely large expansion. To prevent this,
+the self-reference is not considered a macro call. It is passed into
+the preprocessor output unchanged. Consider an example:
+
+.. code-block:: c++
+
+ #define foo (4 + foo)
+
+where ``foo`` is also a variable in your program.
+
+Following the ordinary rules, each reference to ``foo`` will expand
+into ``(4 + foo)`` ; then this will be rescanned and will expand into
+``(4 + (4 + foo))`` ; and so on until the computer runs out of memory.
+
+The self-reference rule cuts this process short after one step, at
+``(4 + foo)``. Therefore, this macro definition has the possibly
+useful effect of causing the program to add 4 to the value of ``foo``
+wherever ``foo`` is referred to.
+
+In most cases, it is a bad idea to take advantage of this feature. A
+person reading the program who sees that ``foo`` is a variable will
+not expect that it is a macro as well. The reader will come across the
+identifier ``foo`` in the program and think its value should be that
+of the variable ``foo``, whereas in fact the value is four greater.
+
+One common, useful use of self-reference is to create a macro which
+expands to itself. If you write
+
+.. code-block:: c++
+
+ #define EPERM EPERM
+
+then the macro ``EPERM`` expands to ``EPERM``. Effectively, it is
+left alone by the preprocessor whenever it's used in running text. You
+can tell that it's a macro with :samp:`#ifdef`. You might do this if you
+want to define numeric constants with an ``enum``, but have
+:samp:`#ifdef` be true for each constant.
+
+If a macro ``x`` expands to use a macro ``y``, and the expansion of
+``y`` refers to the macro ``x``, that is an :dfn:`indirect
+self-reference` of ``x``. ``x`` is not expanded in this case
+either. Thus, if we have
+
+.. code-block:: c++
+
+ #define x (4 + y)
+ #define y (2 * x)
+
+then ``x`` and ``y`` expand as follows:
+
+.. code-block::
+
+ x → (4 + y)
+ → (4 + (2 * x))
+
+ y → (2 * x)
+ → (2 * (4 + y))
+
+Each macro is expanded when it appears in the definition of the other
+macro, but not when it indirectly appears in its own definition.
+
+.. _argument-prescan:
+
+Argument Prescan
+^^^^^^^^^^^^^^^^
+
+.. index:: expansion of arguments
+
+.. index:: macro argument expansion
+
+.. index:: prescan of macro arguments
+
+Macro arguments are completely macro-expanded before they are
+substituted into a macro body, unless they are stringized or pasted
+with other tokens. After substitution, the entire macro body, including
+the substituted arguments, is scanned again for macros to be expanded.
+The result is that the arguments are scanned *twice* to expand
+macro calls in them.
+
+Most of the time, this has no effect. If the argument contained any
+macro calls, they are expanded during the first scan. The result
+therefore contains no macro calls, so the second scan does not change
+it. If the argument were substituted as given, with no prescan, the
+single remaining scan would find the same macro calls and produce the
+same results.
+
+You might expect the double scan to change the results when a
+self-referential macro is used in an argument of another macro
+(see :ref:`self-referential-macros`): the self-referential macro would be
+expanded once in the first scan, and a second time in the second scan.
+However, this is not what happens. The self-references that do not
+expand in the first scan are marked so that they will not expand in the
+second scan either.
+
+You might wonder, 'Why mention the prescan, if it makes no difference?
+And why not skip it and make the preprocessor faster?' The answer is
+that the prescan does make a difference in three special cases:
+
+* Nested calls to a macro.
+
+ We say that :dfn:`nested` calls to a macro occur when a macro's argument
+ contains a call to that very macro. For example, if ``f`` is a macro
+ that expects one argument, ``f (f (1))`` is a nested pair of calls to
+ ``f``. The desired expansion is made by expanding ``f (1)`` and
+ substituting that into the definition of ``f``. The prescan causes
+ the expected result to happen. Without the prescan, ``f (1)`` itself
+ would be substituted as an argument, and the inner use of ``f`` would
+ appear during the main scan as an indirect self-reference and would not
+ be expanded.
+
+* Macros that call other macros that stringize or concatenate.
+
+ If an argument is stringized or concatenated, the prescan does not
+ occur. If you *want* to expand a macro, then stringize or
+ concatenate its expansion, you can do that by causing one macro to call
+ another macro that does the stringizing or concatenation. For
+ instance, if you have
+
+ .. code-block:: c++
+
+ #define AFTERX(x) X_ ## x
+ #define XAFTERX(x) AFTERX(x)
+ #define TABLESIZE 1024
+ #define BUFSIZE TABLESIZE
+
+ then ``AFTERX(BUFSIZE)`` expands to ``X_BUFSIZE``, and
+ ``XAFTERX(BUFSIZE)`` expands to ``X_1024``. (Not to
+ ``X_TABLESIZE``. Prescan always does a complete expansion.)
+
+* Macros used in arguments, whose expansions contain unshielded commas.
+
+ This can cause a macro expanded on the second scan to be called with the
+ wrong number of arguments. Here is an example:
+
+ .. code-block:: c++
+
+ #define foo a,b
+ #define bar(x) lose(x)
+ #define lose(x) (1 + (x))
+
+ We would like ``bar(foo)`` to turn into ``(1 + (foo))``, which
+ would then turn into ``(1 + (a,b))``. Instead, ``bar(foo)``
+ expands into ``lose(a,b)``, and you get an error because ``lose``
+ requires a single argument. In this case, the problem is easily solved
+ by the same parentheses that ought to be used to prevent misnesting of
+ arithmetic operations:
+
+ .. code-block::
+
+ #define foo (a,b)
+ or#define bar(x) lose((x))
+
+ The extra pair of parentheses prevents the comma in ``foo`` 's
+ definition from being interpreted as an argument separator.
+
+.. _newlines-in-arguments:
+
+Newlines in Arguments
+^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: newlines in macro arguments
+
+The invocation of a function-like macro can extend over many logical
+lines. However, in the present implementation, the entire expansion
+comes out on one line. Thus line numbers emitted by the compiler or
+debugger refer to the line the invocation started on, which might be
+different to the line containing the argument causing the problem.
+
+Here is an example illustrating this:
+
+.. code-block:: c++
+
+ #define ignore_second_arg(a,b,c) a; c
+
+ ignore_second_arg (foo (),
+ ignored (),
+ syntax error);
+
+The syntax error triggered by the tokens ``syntax error`` results in
+an error message citing line three---the line of ignore_second_arg---
+even though the problematic code comes from line five.
+
+We consider this a bug, and intend to fix it in the near future.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/object-like-macros.rst b/gcc/doc/cpp/macros/object-like-macros.rst
new file mode 100644
index 00000000000..2ee47f288a3
--- /dev/null
+++ b/gcc/doc/cpp/macros/object-like-macros.rst
@@ -0,0 +1,130 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _object-like-macros:
+
+Object-like Macros
+******************
+
+.. index:: object-like macro
+
+.. index:: symbolic constants
+
+.. index:: manifest constants
+
+An :dfn:`object-like macro` is a simple identifier which will be replaced
+by a code fragment. It is called object-like because it looks like a
+data object in code that uses it. They are most commonly used to give
+symbolic names to numeric constants.
+
+.. index:: #define
+
+You create macros with the :samp:`#define` directive. :samp:`#define` is
+followed by the name of the macro and then the token sequence it should
+be an abbreviation for, which is variously referred to as the macro's
+:dfn:`body`, :dfn:`expansion` or :dfn:`replacement list`. For example,
+
+.. code-block:: c++
+
+ #define BUFFER_SIZE 1024
+
+defines a macro named ``BUFFER_SIZE`` as an abbreviation for the
+token ``1024``. If somewhere after this :samp:`#define` directive
+there comes a C statement of the form
+
+.. code-block:: c++
+
+ foo = (char *) malloc (BUFFER_SIZE);
+
+then the C preprocessor will recognize and :dfn:`expand` the macro
+``BUFFER_SIZE``. The C compiler will see the same tokens as it would
+if you had written
+
+.. code-block:: c++
+
+ foo = (char *) malloc (1024);
+
+By convention, macro names are written in uppercase. Programs are
+easier to read when it is possible to tell at a glance which names are
+macros.
+
+The macro's body ends at the end of the :samp:`#define` line. You may
+continue the definition onto multiple lines, if necessary, using
+backslash-newline. When the macro is expanded, however, it will all
+come out on one line. For example,
+
+.. code-block::
+
+ #define NUMBERS 1, \
+ 2, \
+ 3
+ int x[] = { NUMBERS };
+ → int x[] = { 1, 2, 3 };
+
+The most common visible consequence of this is surprising line numbers
+in error messages.
+
+There is no restriction on what can go in a macro body provided it
+decomposes into valid preprocessing tokens. Parentheses need not
+balance, and the body need not resemble valid C code. (If it does not,
+you may get error messages from the C compiler when you use the macro.)
+
+The C preprocessor scans your program sequentially. Macro definitions
+take effect at the place you write them. Therefore, the following input
+to the C preprocessor
+
+.. code-block:: c++
+
+ foo = X;
+ #define X 4
+ bar = X;
+
+produces
+
+.. code-block:: c++
+
+ foo = X;
+ bar = 4;
+
+When the preprocessor expands a macro name, the macro's expansion
+replaces the macro invocation, then the expansion is examined for more
+macros to expand. For example,
+
+.. code-block::
+
+ #define TABLESIZE BUFSIZE
+ #define BUFSIZE 1024
+ TABLESIZE
+ → BUFSIZE
+ → 1024
+
+``TABLESIZE`` is expanded first to produce ``BUFSIZE``, then that
+macro is expanded to produce the final result, ``1024``.
+
+Notice that ``BUFSIZE`` was not defined when ``TABLESIZE`` was
+defined. The :samp:`#define` for ``TABLESIZE`` uses exactly the
+expansion you specify---in this case, ``BUFSIZE`` ---and does not
+check to see whether it too contains macro names. Only when you
+*use* ``TABLESIZE`` is the result of its expansion scanned for
+more macro names.
+
+This makes a difference if you change the definition of ``BUFSIZE``
+at some point in the source file. ``TABLESIZE``, defined as shown,
+will always expand using the definition of ``BUFSIZE`` that is
+currently in effect:
+
+.. code-block:: c++
+
+ #define BUFSIZE 1020
+ #define TABLESIZE BUFSIZE
+ #undef BUFSIZE
+ #define BUFSIZE 37
+
+Now ``TABLESIZE`` expands (in two stages) to ``37``.
+
+If the expansion of a macro contains its own name, either directly or
+via intermediate macros, it is not expanded again when the expansion is
+examined for more macros. This prevents infinite recursion.
+See :ref:`self-referential-macros`, for the precise details.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/predefined-macros.rst b/gcc/doc/cpp/macros/predefined-macros.rst
new file mode 100644
index 00000000000..0821667d522
--- /dev/null
+++ b/gcc/doc/cpp/macros/predefined-macros.rst
@@ -0,0 +1,658 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _predefined-macros:
+
+Predefined Macros
+*****************
+
+.. index:: predefined macros
+
+Several object-like macros are predefined; you use them without
+supplying their definitions. They fall into three classes: standard,
+common, and system-specific.
+
+In C++, there is a fourth category, the named operators. They act like
+predefined macros, but you cannot undefine them.
+
+.. toctree::
+ :maxdepth: 2
+
+
+.. _standard-predefined-macros:
+
+Standard Predefined Macros
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: standard predefined macros.
+
+The standard predefined macros are specified by the relevant
+language standards, so they are available with all compilers that
+implement those standards. Older compilers may not provide all of
+them. Their names all start with double underscores.
+
+``__FILE__``
+ This macro expands to the name of the current input file, in the form of
+ a C string constant. This is the path by which the preprocessor opened
+ the file, not the short name specified in :samp:`#include` or as the
+ input file name argument. For example,
+ ``"/usr/local/include/myheader.h"`` is a possible expansion of this
+ macro.
+
+``__LINE__``
+ This macro expands to the current input line number, in the form of a
+ decimal integer constant. While we call it a predefined macro, it's
+ a pretty strange macro, since its 'definition' changes with each
+ new line of source code.
+
+ ``__FILE__`` and ``__LINE__`` are useful in generating an error
+ message to report an inconsistency detected by the program; the message
+ can state the source line at which the inconsistency was detected. For
+ example,
+
+.. code-block:: c++
+
+ fprintf (stderr, "Internal error: "
+ "negative string length "
+ "%d at %s, line %d.",
+ length, __FILE__, __LINE__);
+
+An :samp:`#include` directive changes the expansions of ``__FILE__``
+and ``__LINE__`` to correspond to the included file. At the end of
+that file, when processing resumes on the input file that contained
+the :samp:`#include` directive, the expansions of ``__FILE__`` and
+``__LINE__`` revert to the values they had before the
+:samp:`#include` (but ``__LINE__`` is then incremented by one as
+processing moves to the line after the :samp:`#include`).
+
+A :samp:`#line` directive changes ``__LINE__``, and may change
+``__FILE__`` as well. See :ref:`line-control`.
+
+C99 introduced ``__func__``, and GCC has provided ``__FUNCTION__``
+for a long time. Both of these are strings containing the name of the
+current function (there are slight semantic differences; see the GCC
+manual). Neither of them is a macro; the preprocessor does not know the
+name of the current function. They tend to be useful in conjunction
+with ``__FILE__`` and ``__LINE__``, though.
+
+``__DATE__``
+ This macro expands to a string constant that describes the date on which
+ the preprocessor is being run. The string constant contains eleven
+ characters and looks like ``"Feb 12 1996"``. If the day of the
+ month is less than 10, it is padded with a space on the left.
+
+ If GCC cannot determine the current date, it will emit a warning message
+ (once per compilation) and ``__DATE__`` will expand to
+ ``"??? ?? ????"``.
+
+``__TIME__``
+ This macro expands to a string constant that describes the time at
+ which the preprocessor is being run. The string constant contains
+ eight characters and looks like ``"23:59:01"``.
+
+ If GCC cannot determine the current time, it will emit a warning message
+ (once per compilation) and ``__TIME__`` will expand to
+ ``"??:??:??"``.
+
+``__STDC__``
+ In normal operation, this macro expands to the constant 1, to signify
+ that this compiler conforms to ISO Standard C. If GNU CPP is used with
+ a compiler other than GCC, this is not necessarily true; however, the
+ preprocessor always conforms to the standard unless the
+ :option:`-traditional-cpp` option is used.
+
+ This macro is not defined if the :option:`-traditional-cpp` option is used.
+
+ On some hosts, the system compiler uses a different convention, where
+ ``__STDC__`` is normally 0, but is 1 if the user specifies strict
+ conformance to the C Standard. CPP follows the host convention when
+ processing system header files, but when processing user files
+ ``__STDC__`` is always 1. This has been reported to cause problems;
+ for instance, some versions of Solaris provide X Windows headers that
+ expect ``__STDC__`` to be either undefined or 1. See :ref:`invocation`.
+
+``__STDC_VERSION__``
+ This macro expands to the C Standard's version number, a long integer
+ constant of the form ``yyyymmL`` where :samp:`{yyyy}` and
+ :samp:`{mm}` are the year and month of the Standard version. This signifies
+ which version of the C Standard the compiler conforms to. Like
+ ``__STDC__``, this is not necessarily accurate for the entire
+ implementation, unless GNU CPP is being used with GCC.
+
+ The value ``199409L`` signifies the 1989 C standard as amended in
+ 1994, which is the current default; the value ``199901L`` signifies
+ the 1999 revision of the C standard; the value ``201112L``
+ signifies the 2011 revision of the C standard; the value
+ ``201710L`` signifies the 2017 revision of the C standard (which is
+ otherwise identical to the 2011 version apart from correction of
+ defects). An unspecified value larger than ``201710L`` is used for
+ the experimental :option:`-std`:samp:`=c2x` and :option:`-std`:samp:`=gnu2x` modes.
+
+ This macro is not defined if the :option:`-traditional-cpp` option is
+ used, nor when compiling C++ or Objective-C.
+
+``__STDC_HOSTED__``
+ This macro is defined, with value 1, if the compiler's target is a
+ :dfn:`hosted environment`. A hosted environment has the complete
+ facilities of the standard C library available.
+
+``__cplusplus``
+ This macro is defined when the C++ compiler is in use. You can use
+ ``__cplusplus`` to test whether a header is compiled by a C compiler
+ or a C++ compiler. This macro is similar to ``__STDC_VERSION__``, in
+ that it expands to a version number. Depending on the language standard
+ selected, the value of the macro is
+ ``199711L`` for the 1998 C++ standard,
+ ``201103L`` for the 2011 C++ standard,
+ ``201402L`` for the 2014 C++ standard,
+ ``201703L`` for the 2017 C++ standard,
+ ``202002L`` for the 2020 C++ standard,
+ or an unspecified value strictly larger than ``202002L`` for the
+ experimental languages enabled by :option:`-std`:samp:`=c++23` and
+ :option:`-std`:samp:`=gnu++23`.
+
+``__OBJC__``
+ This macro is defined, with value 1, when the Objective-C compiler is in
+ use. You can use ``__OBJC__`` to test whether a header is compiled
+ by a C compiler or an Objective-C compiler.
+
+``__ASSEMBLER__``
+ This macro is defined with value 1 when preprocessing assembly
+ language.
+
+ .. _common-predefined-macros:
+
+Common Predefined Macros
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: common predefined macros
+
+The common predefined macros are GNU C extensions. They are available
+with the same meanings regardless of the machine or operating system on
+which you are using GNU C or GNU Fortran. Their names all start with
+double underscores.
+
+``__COUNTER__``
+ This macro expands to sequential integral values starting from 0. In
+ conjunction with the ``##`` operator, this provides a convenient means to
+ generate unique identifiers. Care must be taken to ensure that
+ ``__COUNTER__`` is not expanded prior to inclusion of precompiled headers
+ which use it. Otherwise, the precompiled headers will not be used.
+
+``__GFORTRAN__``
+ The GNU Fortran compiler defines this.
+
+``__GNUC__`` ``__GNUC_MINOR__`` ``__GNUC_PATCHLEVEL__``
+ These macros are defined by all GNU compilers that use the C
+ preprocessor: C, C++, Objective-C and Fortran. Their values are the major
+ version, minor version, and patch level of the compiler, as integer
+ constants. For example, GCC version :samp:`{x}`. :samp:`{y}`. :samp:`{z}`
+ defines ``__GNUC__`` to :samp:`{x}`, ``__GNUC_MINOR__`` to :samp:`{y}`,
+ and ``__GNUC_PATCHLEVEL__`` to :samp:`{z}`. These
+ macros are also defined if you invoke the preprocessor directly.
+
+ If all you need to know is whether or not your program is being compiled
+ by GCC, or a non-GCC compiler that claims to accept the GNU C dialects,
+ you can simply test ``__GNUC__``. If you need to write code
+ which depends on a specific version, you must be more careful. Each
+ time the minor version is increased, the patch level is reset to zero;
+ each time the major version is increased, the
+ minor version and patch level are reset. If you wish to use the
+ predefined macros directly in the conditional, you will need to write it
+ like this:
+
+ .. code-block:: c++
+
+ /* Test for GCC > 3.2.0 */
+ #if __GNUC__ > 3 || \
+ (__GNUC__ == 3 && (__GNUC_MINOR__ > 2 || \
+ (__GNUC_MINOR__ == 2 && \
+ __GNUC_PATCHLEVEL__ > 0))
+
+ Another approach is to use the predefined macros to
+ calculate a single number, then compare that against a threshold:
+
+ .. code-block:: c++
+
+ #define GCC_VERSION (__GNUC__ * 10000 \
+ + __GNUC_MINOR__ * 100 \
+ + __GNUC_PATCHLEVEL__)
+ ...
+ /* Test for GCC > 3.2.0 */
+ #if GCC_VERSION > 30200
+
+ Many people find this form easier to understand.
+
+``__GNUG__``
+ The GNU C++ compiler defines this. Testing it is equivalent to
+ testing ``(__GNUC__ && __cplusplus)``.
+
+``__STRICT_ANSI__``
+ GCC defines this macro if and only if the :option:`-ansi` switch, or a
+ :option:`-std` switch specifying strict conformance to some version of ISO C
+ or ISO C++, was specified when GCC was invoked. It is defined to :samp:`1`.
+ This macro exists primarily to direct GNU libc's header files to use only
+ definitions found in standard C.
+
+``__BASE_FILE__``
+ This macro expands to the name of the main input file, in the form
+ of a C string constant. This is the source file that was specified
+ on the command line of the preprocessor or C compiler.
+
+``__FILE_NAME__``
+ This macro expands to the basename of the current input file, in the
+ form of a C string constant. This is the last path component by which
+ the preprocessor opened the file. For example, processing
+ ``"/usr/local/include/myheader.h"`` would set this
+ macro to ``"myheader.h"``.
+
+``__INCLUDE_LEVEL__``
+ This macro expands to a decimal integer constant that represents the
+ depth of nesting in include files. The value of this macro is
+ incremented on every :samp:`#include` directive and decremented at the
+ end of every included file. It starts out at 0, its value within the
+ base file specified on the command line.
+
+``__ELF__``
+ This macro is defined if the target uses the ELF object format.
+
+``__VERSION__``
+ This macro expands to a string constant which describes the version of
+ the compiler in use. You should not rely on its contents having any
+ particular form, but it can be counted on to contain at least the
+ release number.
+
+``__OPTIMIZE__`` ``__OPTIMIZE_SIZE__`` ``__NO_INLINE__``
+ These macros describe the compilation mode. ``__OPTIMIZE__`` is
+ defined in all optimizing compilations. ``__OPTIMIZE_SIZE__`` is
+ defined if the compiler is optimizing for size, not speed.
+ ``__NO_INLINE__`` is defined if no functions will be inlined into
+ their callers (when not optimizing, or when inlining has been
+ specifically disabled by :option:`-fno-inline` ).
+
+ These macros cause certain GNU header files to provide optimized
+ definitions, using macros or inline functions, of system library
+ functions. You should not use these macros in any way unless you make
+ sure that programs will execute with the same effect whether or not they
+ are defined. If they are defined, their value is 1.
+
+``__GNUC_GNU_INLINE__``
+ GCC defines this macro if functions declared ``inline`` will be
+ handled in GCC's traditional gnu90 mode. Object files will contain
+ externally visible definitions of all functions declared ``inline``
+ without ``extern`` or ``static``. They will not contain any
+ definitions of any functions declared ``extern inline``.
+
+``__GNUC_STDC_INLINE__``
+ GCC defines this macro if functions declared ``inline`` will be
+ handled according to the ISO C99 or later standards. Object files will contain
+ externally visible definitions of all functions declared ``extern
+ inline``. They will not contain definitions of any functions declared
+ ``inline`` without ``extern``.
+
+ If this macro is defined, GCC supports the ``gnu_inline`` function
+ attribute as a way to always get the gnu90 behavior.
+
+``__CHAR_UNSIGNED__``
+ GCC defines this macro if and only if the data type ``char`` is
+ unsigned on the target machine. It exists to cause the standard header
+ file :samp:`limits.h` to work correctly. You should not use this macro
+ yourself; instead, refer to the standard macros defined in :samp:`limits.h`.
+
+``__WCHAR_UNSIGNED__``
+ Like ``__CHAR_UNSIGNED__``, this macro is defined if and only if the
+ data type ``wchar_t`` is unsigned and the front-end is in C++ mode.
+
+``__REGISTER_PREFIX__``
+ This macro expands to a single token (not a string constant) which is
+ the prefix applied to CPU register names in assembly language for this
+ target. You can use it to write assembly that is usable in multiple
+ environments. For example, in the ``m68k-aout`` environment it
+ expands to nothing, but in the ``m68k-coff`` environment it expands
+ to a single :samp:`%`.
+
+``__USER_LABEL_PREFIX__``
+ This macro expands to a single token which is the prefix applied to
+ user labels (symbols visible to C code) in assembly. For example, in
+ the ``m68k-aout`` environment it expands to an :samp:`_`, but in the
+ ``m68k-coff`` environment it expands to nothing.
+
+ This macro will have the correct definition even if
+ :option:`-f(no-)underscores` is in use, but it will not be correct if
+ target-specific options that adjust this prefix are used (e.g. the
+ OSF/rose :option:`-mno-underscores` option).
+
+``__SIZE_TYPE__`` ``__PTRDIFF_TYPE__`` ``__WCHAR_TYPE__`` ``__WINT_TYPE__`` ``__INTMAX_TYPE__`` ``__UINTMAX_TYPE__`` ``__SIG_ATOMIC_TYPE__`` ``__INT8_TYPE__`` ``__INT16_TYPE__`` ``__INT32_TYPE__`` ``__INT64_TYPE__`` ``__UINT8_TYPE__`` ``__UINT16_TYPE__`` ``__UINT32_TYPE__`` ``__UINT64_TYPE__`` ``__INT_LEAST8_TYPE__`` ``__INT_LEAST16_TYPE__`` ``__INT_LEAST32_TYPE__`` ``__INT_LEAST64_TYPE__`` ``__UINT_LEAST8_TYPE__`` ``__UINT_LEAST16_TYPE__`` ``__UINT_LEAST32_TYPE__`` ``__UINT_LEAST64_TYPE__`` ``__INT_FAST8_TYPE__`` ``__INT_FAST16_TYPE__`` ``__INT_FAST32_TYPE__`` ``__INT_FAST64_TYPE__`` ``__UINT_FAST8_TYPE__`` ``__UINT_FAST16_TYPE__`` ``__UINT_FAST32_TYPE__`` ``__UINT_FAST64_TYPE__`` ``__INTPTR_TYPE__`` ``__UINTPTR_TYPE__``
+ These macros are defined to the correct underlying types for the
+ ``size_t``, ``ptrdiff_t``, ``wchar_t``, ``wint_t``,
+ ``intmax_t``, ``uintmax_t``, ``sig_atomic_t``, ``int8_t``,
+ ``int16_t``, ``int32_t``, ``int64_t``, ``uint8_t``,
+ ``uint16_t``, ``uint32_t``, ``uint64_t``,
+ ``int_least8_t``, ``int_least16_t``, ``int_least32_t``,
+ ``int_least64_t``, ``uint_least8_t``, ``uint_least16_t``,
+ ``uint_least32_t``, ``uint_least64_t``, ``int_fast8_t``,
+ ``int_fast16_t``, ``int_fast32_t``, ``int_fast64_t``,
+ ``uint_fast8_t``, ``uint_fast16_t``, ``uint_fast32_t``,
+ ``uint_fast64_t``, ``intptr_t``, and ``uintptr_t`` typedefs,
+ respectively. They exist to make the standard header files
+ :samp:`stddef.h`, :samp:`stdint.h`, and :samp:`wchar.h` work correctly.
+ You should not use these macros directly; instead, include the
+ appropriate headers and use the typedefs. Some of these macros may
+ not be defined on particular systems if GCC does not provide a
+ :samp:`stdint.h` header on those systems.
+
+``__CHAR_BIT__``
+ Defined to the number of bits used in the representation of the
+ ``char`` data type. It exists to make the standard header given
+ numerical limits work correctly. You should not use
+ this macro directly; instead, include the appropriate headers.
+
+``__SCHAR_MAX__`` ``__WCHAR_MAX__`` ``__SHRT_MAX__`` ``__INT_MAX__`` ``__LONG_MAX__`` ``__LONG_LONG_MAX__`` ``__WINT_MAX__`` ``__SIZE_MAX__`` ``__PTRDIFF_MAX__`` ``__INTMAX_MAX__`` ``__UINTMAX_MAX__`` ``__SIG_ATOMIC_MAX__`` ``__INT8_MAX__`` ``__INT16_MAX__`` ``__INT32_MAX__`` ``__INT64_MAX__`` ``__UINT8_MAX__`` ``__UINT16_MAX__`` ``__UINT32_MAX__`` ``__UINT64_MAX__`` ``__INT_LEAST8_MAX__`` ``__INT_LEAST16_MAX__`` ``__INT_LEAST32_MAX__`` ``__INT_LEAST64_MAX__`` ``__UINT_LEAST8_MAX__`` ``__UINT_LEAST16_MAX__`` ``__UINT_LEAST32_MAX__`` ``__UINT_LEAST64_MAX__`` ``__INT_FAST8_MAX__`` ``__INT_FAST16_MAX__`` ``__INT_FAST32_MAX__`` ``__INT_FAST64_MAX__`` ``__UINT_FAST8_MAX__`` ``__UINT_FAST16_MAX__`` ``__UINT_FAST32_MAX__`` ``__UINT_FAST64_MAX__`` ``__INTPTR_MAX__`` ``__UINTPTR_MAX__`` ``__WCHAR_MIN__`` ``__WINT_MIN__`` ``__SIG_ATOMIC_MIN__``
+ Defined to the maximum value of the ``signed char``, ``wchar_t``,
+ ``signed short``,
+ ``signed int``, ``signed long``, ``signed long long``,
+ ``wint_t``, ``size_t``, ``ptrdiff_t``,
+ ``intmax_t``, ``uintmax_t``, ``sig_atomic_t``, ``int8_t``,
+ ``int16_t``, ``int32_t``, ``int64_t``, ``uint8_t``,
+ ``uint16_t``, ``uint32_t``, ``uint64_t``,
+ ``int_least8_t``, ``int_least16_t``, ``int_least32_t``,
+ ``int_least64_t``, ``uint_least8_t``, ``uint_least16_t``,
+ ``uint_least32_t``, ``uint_least64_t``, ``int_fast8_t``,
+ ``int_fast16_t``, ``int_fast32_t``, ``int_fast64_t``,
+ ``uint_fast8_t``, ``uint_fast16_t``, ``uint_fast32_t``,
+ ``uint_fast64_t``, ``intptr_t``, and ``uintptr_t`` types and
+ to the minimum value of the ``wchar_t``, ``wint_t``, and
+ ``sig_atomic_t`` types respectively. They exist to make the
+ standard header given numerical limits work correctly. You should not
+ use these macros directly; instead, include the appropriate headers.
+ Some of these macros may not be defined on particular systems if GCC
+ does not provide a :samp:`stdint.h` header on those systems.
+
+``__INT8_C`` ``__INT16_C`` ``__INT32_C`` ``__INT64_C`` ``__UINT8_C`` ``__UINT16_C`` ``__UINT32_C`` ``__UINT64_C`` ``__INTMAX_C`` ``__UINTMAX_C``
+ Defined to implementations of the standard :samp:`stdint.h` macros with
+ the same names without the leading ``__``. They exist the make the
+ implementation of that header work correctly. You should not use
+ these macros directly; instead, include the appropriate headers. Some
+ of these macros may not be defined on particular systems if GCC does
+ not provide a :samp:`stdint.h` header on those systems.
+
+``__SCHAR_WIDTH__`` ``__SHRT_WIDTH__`` ``__INT_WIDTH__`` ``__LONG_WIDTH__`` ``__LONG_LONG_WIDTH__`` ``__PTRDIFF_WIDTH__`` ``__SIG_ATOMIC_WIDTH__`` ``__SIZE_WIDTH__`` ``__WCHAR_WIDTH__`` ``__WINT_WIDTH__`` ``__INT_LEAST8_WIDTH__`` ``__INT_LEAST16_WIDTH__`` ``__INT_LEAST32_WIDTH__`` ``__INT_LEAST64_WIDTH__`` ``__INT_FAST8_WIDTH__`` ``__INT_FAST16_WIDTH__`` ``__INT_FAST32_WIDTH__`` ``__INT_FAST64_WIDTH__`` ``__INTPTR_WIDTH__`` ``__INTMAX_WIDTH__``
+ Defined to the bit widths of the corresponding types. They exist to
+ make the implementations of :samp:`limits.h` and :samp:`stdint.h` behave
+ correctly. You should not use these macros directly; instead, include
+ the appropriate headers. Some of these macros may not be defined on
+ particular systems if GCC does not provide a :samp:`stdint.h` header on
+ those systems.
+
+``__SIZEOF_INT__`` ``__SIZEOF_LONG__`` ``__SIZEOF_LONG_LONG__`` ``__SIZEOF_SHORT__`` ``__SIZEOF_POINTER__`` ``__SIZEOF_FLOAT__`` ``__SIZEOF_DOUBLE__`` ``__SIZEOF_LONG_DOUBLE__`` ``__SIZEOF_SIZE_T__`` ``__SIZEOF_WCHAR_T__`` ``__SIZEOF_WINT_T__`` ``__SIZEOF_PTRDIFF_T__``
+ Defined to the number of bytes of the C standard data types: ``int``,
+ ``long``, ``long long``, ``short``, ``void *``, ``float``,
+ ``double``, ``long double``, ``size_t``, ``wchar_t``, ``wint_t``
+ and ``ptrdiff_t``.
+
+``__BYTE_ORDER__`` ``__ORDER_LITTLE_ENDIAN__`` ``__ORDER_BIG_ENDIAN__`` ``__ORDER_PDP_ENDIAN__``
+ ``__BYTE_ORDER__`` is defined to one of the values
+ ``__ORDER_LITTLE_ENDIAN__``, ``__ORDER_BIG_ENDIAN__``, or
+ ``__ORDER_PDP_ENDIAN__`` to reflect the layout of multi-byte and
+ multi-word quantities in memory. If ``__BYTE_ORDER__`` is equal to
+ ``__ORDER_LITTLE_ENDIAN__`` or ``__ORDER_BIG_ENDIAN__``, then
+ multi-byte and multi-word quantities are laid out identically: the
+ byte (word) at the lowest address is the least significant or most
+ significant byte (word) of the quantity, respectively. If
+ ``__BYTE_ORDER__`` is equal to ``__ORDER_PDP_ENDIAN__``, then
+ bytes in 16-bit words are laid out in a little-endian fashion, whereas
+ the 16-bit subwords of a 32-bit quantity are laid out in big-endian
+ fashion.
+
+ You should use these macros for testing like this:
+
+ .. code-block:: c++
+
+ /* Test for a little-endian machine */
+ #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+
+``__FLOAT_WORD_ORDER__``
+ ``__FLOAT_WORD_ORDER__`` is defined to one of the values
+ ``__ORDER_LITTLE_ENDIAN__`` or ``__ORDER_BIG_ENDIAN__`` to reflect
+ the layout of the words of multi-word floating-point quantities.
+
+``__DEPRECATED``
+ This macro is defined, with value 1, when compiling a C++ source file
+ with warnings about deprecated constructs enabled. These warnings are
+ enabled by default, but can be disabled with :option:`-Wno-deprecated`.
+
+``__EXCEPTIONS``
+ This macro is defined, with value 1, when compiling a C++ source file
+ with exceptions enabled. If :option:`-fno-exceptions` is used when
+ compiling the file, then this macro is not defined.
+
+``__GXX_RTTI``
+ This macro is defined, with value 1, when compiling a C++ source file
+ with runtime type identification enabled. If :option:`-fno-rtti` is
+ used when compiling the file, then this macro is not defined.
+
+``__USING_SJLJ_EXCEPTIONS__``
+ This macro is defined, with value 1, if the compiler uses the old
+ mechanism based on ``setjmp`` and ``longjmp`` for exception
+ handling.
+
+``__GXX_EXPERIMENTAL_CXX0X__``
+ This macro is defined when compiling a C++ source file with C++11 features
+ enabled, i.e., for all C++ language dialects except :option:`-std`:samp:`=c++98`
+ and :option:`-std`:samp:`=gnu++98`. This macro is obsolete, but can be used to
+ detect experimental C++0x features in very old versions of GCC. Since
+ GCC 4.7.0 the ``__cplusplus`` macro is defined correctly, so most
+ code should test ``__cplusplus >= 201103L`` instead of using this
+ macro.
+
+``__GXX_WEAK__``
+ This macro is defined when compiling a C++ source file. It has the
+ value 1 if the compiler will use weak symbols, COMDAT sections, or
+ other similar techniques to collapse symbols with 'vague linkage'
+ that are defined in multiple translation units. If the compiler will
+ not collapse such symbols, this macro is defined with value 0. In
+ general, user code should not need to make use of this macro; the
+ purpose of this macro is to ease implementation of the C++ runtime
+ library provided with G++.
+
+``__NEXT_RUNTIME__``
+ This macro is defined, with value 1, if (and only if) the NeXT runtime
+ (as in :option:`-fnext-runtime` ) is in use for Objective-C. If the GNU
+ runtime is used, this macro is not defined, so that you can use this
+ macro to determine which runtime (NeXT or GNU) is being used.
+
+``__LP64__`` ``_LP64``
+ These macros are defined, with value 1, if (and only if) the compilation
+ is for a target where ``long int`` and pointer both use 64-bits and
+ ``int`` uses 32-bit.
+
+``__SSP__``
+ This macro is defined, with value 1, when :option:`-fstack-protector` is in
+ use.
+
+``__SSP_ALL__``
+ This macro is defined, with value 2, when :option:`-fstack-protector-all` is
+ in use.
+
+``__SSP_STRONG__``
+ This macro is defined, with value 3, when :option:`-fstack-protector-strong` is
+ in use.
+
+``__SSP_EXPLICIT__``
+ This macro is defined, with value 4, when :option:`-fstack-protector-explicit` is
+ in use.
+
+``__SANITIZE_ADDRESS__``
+ This macro is defined, with value 1, when :option:`-fsanitize`:samp:`=address`
+ or :option:`-fsanitize`:samp:`=kernel-address` are in use.
+
+``__SANITIZE_THREAD__``
+ This macro is defined, with value 1, when :option:`-fsanitize`:samp:`=thread` is in use.
+
+``__TIMESTAMP__``
+ This macro expands to a string constant that describes the date and time
+ of the last modification of the current source file. The string constant
+ contains abbreviated day of the week, month, day of the month, time in
+ hh:mm:ss form, year and looks like ``"Sun Sep 16 01:03:52 1973"``.
+ If the day of the month is less than 10, it is padded with a space on the left.
+
+ If GCC cannot determine the current date, it will emit a warning message
+ (once per compilation) and ``__TIMESTAMP__`` will expand to
+ ``"??? ??? ?? ??:??:?? ????"``.
+
+``__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1`` ``__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2`` ``__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4`` ``__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8`` ``__GCC_HAVE_SYNC_COMPARE_AND_SWAP_16``
+ These macros are defined when the target processor supports atomic compare
+ and swap operations on operands 1, 2, 4, 8 or 16 bytes in length, respectively.
+
+``__HAVE_SPECULATION_SAFE_VALUE``
+ This macro is defined with the value 1 to show that this version of GCC
+ supports ``__builtin_speculation_safe_value``.
+
+``__GCC_HAVE_DWARF2_CFI_ASM``
+ This macro is defined when the compiler is emitting DWARF CFI directives
+ to the assembler. When this is defined, it is possible to emit those same
+ directives in inline assembly.
+
+``__FP_FAST_FMA`` ``__FP_FAST_FMAF`` ``__FP_FAST_FMAL``
+ These macros are defined with value 1 if the backend supports the
+ ``fma``, ``fmaf``, and ``fmal`` builtin functions, so that
+ the include file :samp:`math.h` can define the macros
+ ``FP_FAST_FMA``, ``FP_FAST_FMAF``, and ``FP_FAST_FMAL``
+ for compatibility with the 1999 C standard.
+
+``__FP_FAST_FMAF16`` ``__FP_FAST_FMAF32`` ``__FP_FAST_FMAF64`` ``__FP_FAST_FMAF128`` ``__FP_FAST_FMAF32X`` ``__FP_FAST_FMAF64X`` ``__FP_FAST_FMAF128X``
+ These macros are defined with the value 1 if the backend supports the
+ ``fma`` functions using the additional ``_Floatn`` and
+ ``_Floatnx`` types that are defined in ISO/IEC TS
+ 18661-3:2015. The include file :samp:`math.h` can define the
+ ``FP_FAST_FMAFn`` and ``FP_FAST_FMAFnx`` macros if
+ the user defined ``__STDC_WANT_IEC_60559_TYPES_EXT__`` before
+ including :samp:`math.h`.
+
+``__GCC_IEC_559``
+ This macro is defined to indicate the intended level of support for
+ IEEE 754 (IEC 60559) floating-point arithmetic. It expands to a
+ nonnegative integer value. If 0, it indicates that the combination of
+ the compiler configuration and the command-line options is not
+ intended to support IEEE 754 arithmetic for ``float`` and
+ ``double`` as defined in C99 and C11 Annex F (for example, that the
+ standard rounding modes and exceptions are not supported, or that
+ optimizations are enabled that conflict with IEEE 754 semantics). If
+ 1, it indicates that IEEE 754 arithmetic is intended to be supported;
+ this does not mean that all relevant language features are supported
+ by GCC. If 2 or more, it additionally indicates support for IEEE
+ 754-2008 (in particular, that the binary encodings for quiet and
+ signaling NaNs are as specified in IEEE 754-2008).
+
+ This macro does not indicate the default state of command-line options
+ that control optimizations that C99 and C11 permit to be controlled by
+ standard pragmas, where those standards do not require a particular
+ default state. It does not indicate whether optimizations respect
+ signaling NaN semantics (the macro for that is
+ ``__SUPPORT_SNAN__`` ). It does not indicate support for decimal
+ floating point or the IEEE 754 binary16 and binary128 types.
+
+``__GCC_IEC_559_COMPLEX``
+ This macro is defined to indicate the intended level of support for
+ IEEE 754 (IEC 60559) floating-point arithmetic for complex numbers, as
+ defined in C99 and C11 Annex G. It expands to a nonnegative integer
+ value. If 0, it indicates that the combination of the compiler
+ configuration and the command-line options is not intended to support
+ Annex G requirements (for example, because :option:`-fcx-limited-range`
+ was used). If 1 or more, it indicates that it is intended to support
+ those requirements; this does not mean that all relevant language
+ features are supported by GCC.
+
+``__NO_MATH_ERRNO__``
+ This macro is defined if :option:`-fno-math-errno` is used, or enabled
+ by another option such as :option:`-ffast-math` or by default.
+
+``__GNUC_EXECUTION_CHARSET_NAME`` ``__GNUC_WIDE_EXECUTION_CHARSET_NAME``
+ These macros are defined to expand to a narrow string literal of
+ the name of the narrow and wide compile-time execution character
+ set used. It directly reflects the name passed to the options
+ :option:`-fexec-charset` and :option:`-fwide-exec-charset`, or the defaults
+ documented for those options (that is, it can expand to something like
+ ``"UTF-8"`` ). See :ref:`invocation`.
+
+ .. _system-specific-predefined-macros:
+
+System-specific Predefined Macros
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: system-specific predefined macros
+
+.. index:: predefined macros, system-specific
+
+.. index:: reserved namespace
+
+The C preprocessor normally predefines several macros that indicate what
+type of system and machine is in use. They are obviously different on
+each target supported by GCC. This manual, being for all systems and
+machines, cannot tell you what their names are, but you can use
+:command:`cpp -dM` to see them all. See :ref:`invocation`. All system-specific
+predefined macros expand to a constant value, so you can test them with
+either :samp:`#ifdef` or :samp:`#if`.
+
+The C standard requires that all system-specific macros be part of the
+:dfn:`reserved namespace`. All names which begin with two underscores,
+or an underscore and a capital letter, are reserved for the compiler and
+library to use as they wish. However, historically system-specific
+macros have had names with no special prefix; for instance, it is common
+to find ``unix`` defined on Unix systems. For all such macros, GCC
+provides a parallel macro with two underscores added at the beginning
+and the end. If ``unix`` is defined, ``__unix__`` will be defined
+too. There will never be more than two underscores; the parallel of
+``_mips`` is ``__mips__``.
+
+When the :option:`-ansi` option, or any :option:`-std` option that
+requests strict conformance, is given to the compiler, all the
+system-specific predefined macros outside the reserved namespace are
+suppressed. The parallel macros, inside the reserved namespace, remain
+defined.
+
+We are slowly phasing out all predefined macros which are outside the
+reserved namespace. You should never use them in new programs, and we
+encourage you to correct older code to use the parallel macros whenever
+you find it. We don't recommend you use the system-specific macros that
+are in the reserved namespace, either. It is better in the long run to
+check specifically for features you need, using a tool such as
+:command:`autoconf`.
+
+.. _c++-named-operators:
+
+C++ Named Operators
+^^^^^^^^^^^^^^^^^^^
+
+.. index:: named operators
+
+.. index:: C++ named operators
+
+.. index:: iso646.h
+
+In C++, there are eleven keywords which are simply alternate spellings
+of operators normally written with punctuation. These keywords are
+treated as such even in the preprocessor. They function as operators in
+:samp:`#if`, and they cannot be defined as macros or poisoned. In C, you
+can request that those keywords take their C++ meaning by including
+:samp:`iso646.h`. That header defines each one as a normal object-like
+macro expanding to the appropriate punctuator.
+
+These are the named operators and their corresponding punctuators:
+
+============== ==========
+Named Operator Punctuator
+``and`` ``&&``
+``and_eq`` ``&=``
+``bitand`` ``&``
+``bitor`` ``|``
+``compl`` ``~``
+``not`` ``!``
+``not_eq`` ``!=``
+``or`` ``||``
+``or_eq`` ``|=``
+``xor`` ``^``
+``xor_eq`` ``^=``
+============== ==========
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/stringizing.rst b/gcc/doc/cpp/macros/stringizing.rst
new file mode 100644
index 00000000000..94bf3b785b5
--- /dev/null
+++ b/gcc/doc/cpp/macros/stringizing.rst
@@ -0,0 +1,88 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _stringizing:
+
+Stringizing
+***********
+
+.. index:: stringizing
+
+.. index:: # operator
+
+Sometimes you may want to convert a macro argument into a string
+constant. Parameters are not replaced inside string constants, but you
+can use the :samp:`#` preprocessing operator instead. When a macro
+parameter is used with a leading :samp:`#`, the preprocessor replaces it
+with the literal text of the actual argument, converted to a string
+constant. Unlike normal parameter replacement, the argument is not
+macro-expanded first. This is called :dfn:`stringizing`.
+
+There is no way to combine an argument with surrounding text and
+stringize it all together. Instead, you can write a series of adjacent
+string constants and stringized arguments. The preprocessor
+replaces the stringized arguments with string constants. The C
+compiler then combines all the adjacent string constants into one
+long string.
+
+Here is an example of a macro definition that uses stringizing:
+
+.. code-block::
+
+ #define WARN_IF(EXP) \
+ do { if (EXP) \
+ fprintf (stderr, "Warning: " #EXP "\n"); } \
+ while (0)
+ WARN_IF (x == 0);
+ → do { if (x == 0)
+ fprintf (stderr, "Warning: " "x == 0" "\n"); } while (0);
+
+The argument for ``EXP`` is substituted once, as-is, into the
+``if`` statement, and once, stringized, into the argument to
+``fprintf``. If ``x`` were a macro, it would be expanded in the
+``if`` statement, but not in the string.
+
+The ``do`` and ``while (0)`` are a kludge to make it possible to
+write ``WARN_IF (arg);``, which the resemblance of
+``WARN_IF`` to a function would make C programmers want to do; see
+Swallowing the Semicolon.
+
+Stringizing in C involves more than putting double-quote characters
+around the fragment. The preprocessor backslash-escapes the quotes
+surrounding embedded string constants, and all backslashes within string and
+character constants, in order to get a valid C string constant with the
+proper contents. Thus, stringizing ``p = "foo\n";`` results in
+``"p = \"foo\\n\";"``. However, backslashes that are not inside string
+or character constants are not duplicated: :samp:`\\n` by itself
+stringizes to ``"\n"``.
+
+All leading and trailing whitespace in text being stringized is
+ignored. Any sequence of whitespace in the middle of the text is
+converted to a single space in the stringized result. Comments are
+replaced by whitespace long before stringizing happens, so they
+never appear in stringized text.
+
+There is no way to convert a macro argument into a character constant.
+
+If you want to stringize the result of expansion of a macro argument,
+you have to use two levels of macros.
+
+.. code-block::
+
+ #define xstr(s) str(s)
+ #define str(s) #s
+ #define foo 4
+ str (foo)
+ → "foo"
+ xstr (foo)
+ → xstr (4)
+ → str (4)
+ → "4"
+
+``s`` is stringized when it is used in ``str``, so it is not
+macro-expanded first. But ``s`` is an ordinary argument to
+``xstr``, so it is completely macro-expanded before ``xstr``
+itself is expanded (see :ref:`argument-prescan`). Therefore, by the time
+``str`` gets to its argument, it has already been macro-expanded.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/undefining-and-redefining-macros.rst b/gcc/doc/cpp/macros/undefining-and-redefining-macros.rst
new file mode 100644
index 00000000000..3194a6838c2
--- /dev/null
+++ b/gcc/doc/cpp/macros/undefining-and-redefining-macros.rst
@@ -0,0 +1,71 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _undefining-and-redefining-macros:
+
+Undefining and Redefining Macros
+********************************
+
+.. index:: undefining macros
+
+.. index:: redefining macros
+
+.. index:: #undef
+
+If a macro ceases to be useful, it may be :dfn:`undefined` with the
+:samp:`#undef` directive. :samp:`#undef` takes a single argument, the
+name of the macro to undefine. You use the bare macro name, even if the
+macro is function-like. It is an error if anything appears on the line
+after the macro name. :samp:`#undef` has no effect if the name is not a
+macro.
+
+.. code-block::
+
+ #define FOO 4
+ x = FOO; → x = 4;
+ #undef FOO
+ x = FOO; → x = FOO;
+
+Once a macro has been undefined, that identifier may be :dfn:`redefined`
+as a macro by a subsequent :samp:`#define` directive. The new definition
+need not have any resemblance to the old definition.
+
+However, if an identifier which is currently a macro is redefined, then
+the new definition must be :dfn:`effectively the same` as the old one.
+Two macro definitions are effectively the same if:
+
+* Both are the same type of macro (object- or function-like).
+
+* All the tokens of the replacement list are the same.
+
+* If there are any parameters, they are the same.
+
+* Whitespace appears in the same places in both. It need not be
+ exactly the same amount of whitespace, though. Remember that comments
+ count as whitespace.
+
+These definitions are effectively the same:
+
+.. code-block:: c++
+
+ #define FOUR (2 + 2)
+ #define FOUR (2 + 2)
+ #define FOUR (2 /* two */ + 2)
+
+but these are not:
+
+.. code-block:: c++
+
+ #define FOUR (2 + 2)
+ #define FOUR ( 2+2 )
+ #define FOUR (2 * 2)
+ #define FOUR(score,and,seven,years,ago) (2 + 2)
+
+If a macro is redefined with a definition that is not effectively the
+same as the old one, the preprocessor issues a warning and changes the
+macro to use the new definition. If the new definition is effectively
+the same, the redefinition is silently ignored. This allows, for
+instance, two different headers to define a common macro. The
+preprocessor will only complain if the definitions do not match.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/variadic-macros.rst b/gcc/doc/cpp/macros/variadic-macros.rst
new file mode 100644
index 00000000000..c96ab107654
--- /dev/null
+++ b/gcc/doc/cpp/macros/variadic-macros.rst
@@ -0,0 +1,145 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _variadic-macros:
+
+Variadic Macros
+***************
+
+.. index:: variable number of arguments
+
+.. index:: macros with variable arguments
+
+.. index:: variadic macros
+
+A macro can be declared to accept a variable number of arguments much as
+a function can. The syntax for defining the macro is similar to that of
+a function. Here is an example:
+
+.. code-block:: c++
+
+ #define eprintf(...) fprintf (stderr, __VA_ARGS__)
+
+This kind of macro is called :dfn:`variadic`. When the macro is invoked,
+all the tokens in its argument list after the last named argument (this
+macro has none), including any commas, become the :dfn:`variable
+argument`. This sequence of tokens replaces the identifier
+``__VA_ARGS__`` in the macro body wherever it appears. Thus, we
+have this expansion:
+
+.. code-block::
+
+ eprintf ("%s:%d: ", input_file, lineno)
+ → fprintf (stderr, "%s:%d: ", input_file, lineno)
+
+The variable argument is completely macro-expanded before it is inserted
+into the macro expansion, just like an ordinary argument. You may use
+the :samp:`#` and :samp:`##` operators to stringize the variable argument
+or to paste its leading or trailing token with another token. (But see
+below for an important special case for :samp:`##`.)
+
+If your macro is complicated, you may want a more descriptive name for
+the variable argument than ``__VA_ARGS__``. CPP permits
+this, as an extension. You may write an argument name immediately
+before the :samp:`...`; that name is used for the variable argument.
+The ``eprintf`` macro above could be written
+
+.. code-block:: c++
+
+ #define eprintf(args...) fprintf (stderr, args)
+
+using this extension. You cannot use ``__VA_ARGS__`` and this
+extension in the same macro.
+
+You can have named arguments as well as variable arguments in a variadic
+macro. We could define ``eprintf`` like this, instead:
+
+.. code-block:: c++
+
+ #define eprintf(format, ...) fprintf (stderr, format, __VA_ARGS__)
+
+This formulation looks more descriptive, but historically it was less
+flexible: you had to supply at least one argument after the format
+string. In standard C, you could not omit the comma separating the
+named argument from the variable arguments. (Note that this
+restriction has been lifted in C++2a, and never existed in GNU C; see
+below.)
+
+Furthermore, if you left the variable argument empty, you would have
+gotten a syntax error, because there would have been an extra comma
+after the format string.
+
+.. code-block::
+
+ eprintf("success!\n", );
+ → fprintf(stderr, "success!\n", );
+
+This has been fixed in C++2a, and GNU CPP also has a pair of
+extensions which deal with this problem.
+
+First, in GNU CPP, and in C++ beginning in C++2a, you are allowed to
+leave the variable argument out entirely:
+
+.. code-block::
+
+ eprintf ("success!\n")
+ → fprintf(stderr, "success!\n", );
+
+Second, C++2a introduces the ``__VA_OPT__`` function macro.
+This macro may only appear in the definition of a variadic macro. If
+the variable argument has any tokens, then a ``__VA_OPT__``
+invocation expands to its argument; but if the variable argument does
+not have any tokens, the ``__VA_OPT__`` expands to nothing:
+
+.. code-block:: c++
+
+ #define eprintf(format, ...) \
+ fprintf (stderr, format __VA_OPT__(,) __VA_ARGS__)
+
+``__VA_OPT__`` is also available in GNU C and GNU C++.
+
+Historically, GNU CPP has also had another extension to handle the
+trailing comma: the :samp:`##` token paste operator has a special
+meaning when placed between a comma and a variable argument. Despite
+the introduction of ``__VA_OPT__``, this extension remains
+supported in GNU CPP, for backward compatibility. If you write
+
+.. code-block:: c++
+
+ #define eprintf(format, ...) fprintf (stderr, format, ##__VA_ARGS__)
+
+and the variable argument is left out when the ``eprintf`` macro is
+used, then the comma before the :samp:`##` will be deleted. This does
+*not* happen if you pass an empty argument, nor does it happen if
+the token preceding :samp:`##` is anything other than a comma.
+
+.. code-block::
+
+ eprintf ("success!\n")
+ → fprintf(stderr, "success!\n");
+
+The above explanation is ambiguous about the case where the only macro
+parameter is a variable arguments parameter, as it is meaningless to
+try to distinguish whether no argument at all is an empty argument or
+a missing argument.
+CPP retains the comma when conforming to a specific C
+standard. Otherwise the comma is dropped as an extension to the standard.
+
+The C standard
+mandates that the only place the identifier ``__VA_ARGS__``
+can appear is in the replacement list of a variadic macro. It may not
+be used as a macro name, macro argument name, or within a different type
+of macro. It may also be forbidden in open text; the standard is
+ambiguous. We recommend you avoid using it except for its defined
+purpose.
+
+Likewise, C++ forbids ``__VA_OPT__`` anywhere outside the
+replacement list of a variadic macro.
+
+Variadic macros became a standard part of the C language with C99.
+GNU CPP previously supported them
+with a named variable argument
+(:samp:`args...`, not :samp:`...` and ``__VA_ARGS__`` ), which
+is still supported for backward compatibility.
\ No newline at end of file
diff --git a/gcc/doc/cpp/obsolete-features.rst b/gcc/doc/cpp/obsolete-features.rst
new file mode 100644
index 00000000000..7524b7d1a17
--- /dev/null
+++ b/gcc/doc/cpp/obsolete-features.rst
@@ -0,0 +1,100 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _obsolete-features:
+
+Obsolete Features
+*****************
+
+CPP has some features which are present mainly for compatibility with
+older programs. We discourage their use in new code. In some cases,
+we plan to remove the feature in a future version of GCC.
+
+Assertions
+^^^^^^^^^^
+
+.. index:: assertions
+
+:dfn:`Assertions` are a deprecated alternative to macros in writing
+conditionals to test what sort of computer or system the compiled
+program will run on. Assertions are usually predefined, but you can
+define them with preprocessing directives or command-line options.
+
+Assertions were intended to provide a more systematic way to describe
+the compiler's target system and we added them for compatibility with
+existing compilers. In practice they are just as unpredictable as the
+system-specific predefined macros. In addition, they are not part of
+any standard, and only a few compilers support them.
+Therefore, the use of assertions is **less** portable than the use
+of system-specific predefined macros. We recommend you do not use them at
+all.
+
+.. index:: predicates
+
+An assertion looks like this:
+
+.. code-block:: c++
+
+ #predicate (answer)
+
+:samp:`{predicate}` must be a single identifier. :samp:`{answer}` can be any
+sequence of tokens; all characters are significant except for leading
+and trailing whitespace, and differences in internal whitespace
+sequences are ignored. (This is similar to the rules governing macro
+redefinition.) Thus, ``(x + y)`` is different from ``(x+y)`` but
+equivalent to ``( x + y )``. Parentheses do not nest inside an
+answer.
+
+.. index:: testing predicates
+
+To test an assertion, you write it in an :samp:`#if`. For example, this
+conditional succeeds if either ``vax`` or ``ns16000`` has been
+asserted as an answer for ``machine``.
+
+.. code-block:: c++
+
+ #if #machine (vax) || #machine (ns16000)
+
+You can test whether *any* answer is asserted for a predicate by
+omitting the answer in the conditional:
+
+.. code-block:: c++
+
+ #if #machine
+
+.. index:: #assert
+
+Assertions are made with the :samp:`#assert` directive. Its sole
+argument is the assertion to make, without the leading :samp:`#` that
+identifies assertions in conditionals.
+
+.. code-block:: c++
+
+ #assert predicate (answer)
+
+You may make several assertions with the same predicate and different
+answers. Subsequent assertions do not override previous ones for the
+same predicate. All the answers for any given predicate are
+simultaneously true.
+
+.. index:: assertions, canceling
+
+.. index:: #unassert
+
+Assertions can be canceled with the :samp:`#unassert` directive. It
+has the same syntax as :samp:`#assert`. In that form it cancels only the
+answer which was specified on the :samp:`#unassert` line; other answers
+for that predicate remain true. You can cancel an entire predicate by
+leaving out the answer:
+
+.. code-block:: c++
+
+ #unassert predicate
+
+In either form, if no such assertion has been made, :samp:`#unassert` has
+no effect.
+
+You can also make or cancel assertions using command-line options.
+See :ref:`invocation`.
\ No newline at end of file
diff --git a/gcc/doc/cpp/option-index.rst b/gcc/doc/cpp/option-index.rst
new file mode 100644
index 00000000000..77718164b12
--- /dev/null
+++ b/gcc/doc/cpp/option-index.rst
@@ -0,0 +1,6 @@
+Option Index
+============
+
+.. only:: html
+
+ :ref:`genindex`
\ No newline at end of file
diff --git a/gcc/doc/cpp/other-directives.rst b/gcc/doc/cpp/other-directives.rst
new file mode 100644
index 00000000000..1799c04f558
--- /dev/null
+++ b/gcc/doc/cpp/other-directives.rst
@@ -0,0 +1,32 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+ .. _other-directives:
+
+Other Directives
+----------------
+
+.. index:: #ident
+
+.. index:: #sccs
+
+The :samp:`#ident` directive takes one argument, a string constant. On
+some systems, that string constant is copied into a special segment of
+the object file. On other systems, the directive is ignored. The
+:samp:`#sccs` directive is a synonym for :samp:`#ident`.
+
+These directives are not part of the C standard, but they are not
+official GNU extensions either. What historical information we have
+been able to find, suggests they originated with System V.
+
+.. index:: null directive
+
+The :dfn:`null directive` consists of a :samp:`#` followed by a newline,
+with only whitespace (including comments) in between. A null directive
+is understood as a preprocessing directive but has no effect on the
+preprocessor output. The primary significance of the existence of the
+null directive is that an input line consisting of just a :samp:`#` will
+produce no output, rather than a line of output containing just a
+:samp:`#`. Supposedly some old C programs contain such lines.
\ No newline at end of file
diff --git a/gcc/doc/cpp/overview.rst b/gcc/doc/cpp/overview.rst
new file mode 100644
index 00000000000..c09276d640c
--- /dev/null
+++ b/gcc/doc/cpp/overview.rst
@@ -0,0 +1,66 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _overview:
+
+Overview
+--------
+
+The C preprocessor, often known as :dfn:`cpp`, is a :dfn:`macro processor`
+that is used automatically by the C compiler to transform your program
+before compilation. It is called a macro processor because it allows
+you to define :dfn:`macros`, which are brief abbreviations for longer
+constructs.
+
+The C preprocessor is intended to be used only with C, C++, and
+Objective-C source code. In the past, it has been abused as a general
+text processor. It will choke on input which does not obey C's lexical
+rules. For example, apostrophes will be interpreted as the beginning of
+character constants, and cause errors. Also, you cannot rely on it
+preserving characteristics of the input which are not significant to
+C-family languages. If a Makefile is preprocessed, all the hard tabs
+will be removed, and the Makefile will not work.
+
+Having said that, you can often get away with using cpp on things which
+are not C. Other Algol-ish programming languages are often safe
+(Ada, etc.) So is assembly, with caution. :option:`-traditional-cpp`
+mode preserves more white space, and is otherwise more permissive. Many
+of the problems can be avoided by writing C or C++ style comments
+instead of native language comments, and keeping macros simple.
+
+Wherever possible, you should use a preprocessor geared to the language
+you are writing in. Modern versions of the GNU assembler have macro
+facilities. Most high level programming languages have their own
+conditional compilation and inclusion mechanism. If all else fails,
+try a true general text processor, such as GNU M4.
+
+C preprocessors vary in some details. This manual discusses the GNU C
+preprocessor, which provides a small superset of the features of ISO
+Standard C. In its default mode, the GNU C preprocessor does not do a
+few things required by the standard. These are features which are
+rarely, if ever, used, and may cause surprising changes to the meaning
+of a program which does not expect them. To get strict ISO Standard C,
+you should use the :option:`-std`:samp:`=c90`, :option:`-std`:samp:`=c99`,
+:option:`-std`:samp:`=c11` or :option:`-std`:samp:`=c17` options, depending
+on which version of the standard you want. To get all the mandatory
+diagnostics, you must also use :option:`-pedantic`. See :ref:`invocation`.
+
+This manual describes the behavior of the ISO preprocessor. To
+minimize gratuitous differences, where the ISO preprocessor's
+behavior does not conflict with traditional semantics, the
+traditional preprocessor should behave the same way. The various
+differences that do exist are detailed in the section Traditional
+Mode.
+
+For clarity, unless noted otherwise, references to :samp:`CPP` in this
+manual refer to GNU CPP.
+
+.. toctree::
+ :maxdepth: 2
+
+ character-sets
+ initial-processing
+ tokenization
+ the-preprocessing-language
\ No newline at end of file
diff --git a/gcc/doc/cpp/pragmas.rst b/gcc/doc/cpp/pragmas.rst
new file mode 100644
index 00000000000..40d037260a9
--- /dev/null
+++ b/gcc/doc/cpp/pragmas.rst
@@ -0,0 +1,121 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _pragmas:
+
+Pragmas
+-------
+
+.. index:: pragma directive
+
+The :samp:`#pragma` directive is the method specified by the C standard
+for providing additional information to the compiler, beyond what is
+conveyed in the language itself. The forms of this directive
+(commonly known as :dfn:`pragmas`) specified by C standard are prefixed with
+``STDC``. A C compiler is free to attach any meaning it likes to other
+pragmas. Most GNU-defined, supported pragmas have been given a
+``GCC`` prefix.
+
+.. index:: _Pragma
+
+C99 introduced the ``_Pragma`` operator. This feature addresses a
+major problem with :samp:`#pragma`: being a directive, it cannot be
+produced as the result of macro expansion. ``_Pragma`` is an
+operator, much like ``sizeof`` or ``defined``, and can be embedded
+in a macro.
+
+Its syntax is ``_Pragma (string-literal)``, where
+:samp:`{string-literal}` can be either a normal or wide-character string
+literal. It is destringized, by replacing all :samp:`\\\\` with a single
+:samp:`\\` and all :samp:`\\"` with a :samp:`"`. The result is then
+processed as if it had appeared as the right hand side of a
+:samp:`#pragma` directive. For example,
+
+.. code-block:: c++
+
+ _Pragma ("GCC dependency \"parse.y\"")
+
+has the same effect as ``#pragma GCC dependency "parse.y"``. The
+same effect could be achieved using macros, for example
+
+.. code-block:: c++
+
+ #define DO_PRAGMA(x) _Pragma (#x)
+ DO_PRAGMA (GCC dependency "parse.y")
+
+The standard is unclear on where a ``_Pragma`` operator can appear.
+The preprocessor does not accept it within a preprocessing conditional
+directive like :samp:`#if`. To be safe, you are probably best keeping it
+out of directives other than :samp:`#define`, and putting it on a line of
+its own.
+
+This manual documents the pragmas which are meaningful to the
+preprocessor itself. Other pragmas are meaningful to the C or C++
+compilers. They are documented in the GCC manual.
+
+GCC plugins may provide their own pragmas.
+
+``#pragma GCC dependency``
+ ``#pragma GCC dependency`` allows you to check the relative dates of
+ the current file and another file. If the other file is more recent than
+ the current file, a warning is issued. This is useful if the current
+ file is derived from the other file, and should be regenerated. The
+ other file is searched for using the normal include search path.
+ Optional trailing text can be used to give more information in the
+ warning message.
+
+ .. code-block:: c++
+
+ #pragma GCC dependency "parse.y"
+ #pragma GCC dependency "/usr/include/time.h" rerun fixincludes
+
+``#pragma GCC poison``
+ Sometimes, there is an identifier that you want to remove completely
+ from your program, and make sure that it never creeps back in. To
+ enforce this, you can :dfn:`poison` the identifier with this pragma.
+ ``#pragma GCC poison`` is followed by a list of identifiers to
+ poison. If any of those identifiers appears anywhere in the source
+ after the directive, it is a hard error. For example,
+
+ .. code-block:: c++
+
+ #pragma GCC poison printf sprintf fprintf
+ sprintf(some_string, "hello");
+
+ will produce an error.
+
+ If a poisoned identifier appears as part of the expansion of a macro
+ which was defined before the identifier was poisoned, it will *not*
+ cause an error. This lets you poison an identifier without worrying
+ about system headers defining macros that use it.
+
+ For example,
+
+ .. code-block:: c++
+
+ #define strrchr rindex
+ #pragma GCC poison rindex
+ strrchr(some_string, 'h');
+
+ will not produce an error.
+
+``#pragma GCC system_header``
+ This pragma takes no arguments. It causes the rest of the code in the
+ current file to be treated as if it came from a system header.
+ See :ref:`system-headers`.
+
+``#pragma GCC warning`` :samp:`{#pragma GCC error}#pragma GCC error`
+ ``#pragma GCC warning "message"`` causes the preprocessor to issue
+ a warning diagnostic with the text :samp:`message`. The message
+ contained in the pragma must be a single string literal. Similarly,
+ ``#pragma GCC error "message"`` issues an error message. Unlike
+ the :samp:`#warning` and :samp:`#error` directives, these pragmas can be
+ embedded in preprocessor macros using :samp:`_Pragma`.
+
+``#pragma once``
+ If ``#pragma once`` is seen when scanning a header file, that
+ file will never be read again, no matter what. It is a less-portable
+ alternative to using :samp:`#ifndef` to guard the contents of header files
+ against multiple inclusions.
\ No newline at end of file
diff --git a/gcc/doc/cpp/preprocessor-output.rst b/gcc/doc/cpp/preprocessor-output.rst
new file mode 100644
index 00000000000..8aff8b36ea0
--- /dev/null
+++ b/gcc/doc/cpp/preprocessor-output.rst
@@ -0,0 +1,86 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _preprocessor-output:
+
+Preprocessor Output
+-------------------
+
+When the C preprocessor is used with the C, C++, or Objective-C
+compilers, it is integrated into the compiler and communicates a stream
+of binary tokens directly to the compiler's parser. However, it can
+also be used in the more conventional standalone mode, where it produces
+textual output.
+
+.. FIXME: Document the library interface.
+
+.. index:: output format
+
+The output from the C preprocessor looks much like the input, except
+that all preprocessing directive lines have been replaced with blank
+lines and all comments with spaces. Long runs of blank lines are
+discarded.
+
+The ISO standard specifies that it is implementation defined whether a
+preprocessor preserves whitespace between tokens, or replaces it with
+e.g. a single space. In GNU CPP, whitespace between tokens is collapsed
+to become a single space, with the exception that the first token on a
+non-directive line is preceded with sufficient spaces that it appears in
+the same column in the preprocessed output that it appeared in the
+original source file. This is so the output is easy to read.
+CPP does not insert any
+whitespace where there was none in the original source, except where
+necessary to prevent an accidental token paste.
+
+.. index:: linemarkers
+
+Source file name and line number information is conveyed by lines
+of the form
+
+.. code-block:: c++
+
+ # linenum filename flags
+
+These are called :dfn:`linemarkers`. They are inserted as needed into
+the output (but never within a string or character constant). They mean
+that the following line originated in file :samp:`{filename}` at line
+:samp:`{linenum}`. :samp:`{filename}` will never contain any non-printing
+characters; they are replaced with octal escape sequences.
+
+After the file name comes zero or more flags, which are :samp:`1`,
+:samp:`2`, :samp:`3`, or :samp:`4`. If there are multiple flags, spaces
+separate them. Here is what the flags mean:
+
+:samp:`1`
+ This indicates the start of a new file.
+
+:samp:`2`
+ This indicates returning to a file (after having included another file).
+
+:samp:`3`
+ This indicates that the following text comes from a system header file,
+ so certain warnings should be suppressed.
+
+:samp:`4`
+ This indicates that the following text should be treated as being
+ wrapped in an implicit ``extern "C"`` block.
+
+ .. maybe cross reference SYSTEM_IMPLICIT_EXTERN_C
+
+As an extension, the preprocessor accepts linemarkers in non-assembler
+input files. They are treated like the corresponding :samp:`#line`
+directive, (see :ref:`line-control`), except that trailing flags are
+permitted, and are interpreted with the meanings described above. If
+multiple flags are given, they must be in ascending order.
+
+Some directives may be duplicated in the output of the preprocessor.
+These are :samp:`#ident` (always), :samp:`#pragma` (only if the
+preprocessor does not handle the pragma itself), and :samp:`#define` and
+:samp:`#undef` (with certain debugging options). If this happens, the
+:samp:`#` of the directive will always be in the first column, and there
+will be no space between the :samp:`#` and the directive name. If macro
+expansion happens to generate tokens which might be mistaken for a
+duplicated directive, a space will be inserted between the :samp:`#` and
+the directive name.
\ No newline at end of file
diff --git a/gcc/doc/cpp/the-preprocessing-language.rst b/gcc/doc/cpp/the-preprocessing-language.rst
new file mode 100644
index 00000000000..83136439cc8
--- /dev/null
+++ b/gcc/doc/cpp/the-preprocessing-language.rst
@@ -0,0 +1,75 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _the-preprocessing-language:
+
+The preprocessing language
+**************************
+
+.. index:: directives
+
+.. index:: preprocessing directives
+
+.. index:: directive line
+
+.. index:: directive name
+
+After tokenization, the stream of tokens may simply be passed straight
+to the compiler's parser. However, if it contains any operations in the
+:dfn:`preprocessing language`, it will be transformed first. This stage
+corresponds roughly to the standard's 'translation phase 4' and is
+what most people think of as the preprocessor's job.
+
+The preprocessing language consists of :dfn:`directives` to be executed
+and :dfn:`macros` to be expanded. Its primary capabilities are:
+
+* Inclusion of header files. These are files of declarations that can be
+ substituted into your program.
+
+* Macro expansion. You can define :dfn:`macros`, which are abbreviations
+ for arbitrary fragments of C code. The preprocessor will replace the
+ macros with their definitions throughout the program. Some macros are
+ automatically defined for you.
+
+* Conditional compilation. You can include or exclude parts of the
+ program according to various conditions.
+
+* Line control. If you use a program to combine or rearrange source files
+ into an intermediate file which is then compiled, you can use line
+ control to inform the compiler where each source line originally came
+ from.
+
+* Diagnostics. You can detect problems at compile time and issue errors
+ or warnings.
+
+There are a few more, less useful, features.
+
+Except for expansion of predefined macros, all these operations are
+triggered with :dfn:`preprocessing directives`. Preprocessing directives
+are lines in your program that start with :samp:`#`. Whitespace is
+allowed before and after the :samp:`#`. The :samp:`#` is followed by an
+identifier, the :dfn:`directive name`. It specifies the operation to
+perform. Directives are commonly referred to as :samp:`#{name}`
+where :samp:`{name}` is the directive name. For example, :samp:`#define` is
+the directive that defines a macro.
+
+The :samp:`#` which begins a directive cannot come from a macro
+expansion. Also, the directive name is not macro expanded. Thus, if
+``foo`` is defined as a macro expanding to ``define``, that does
+not make :samp:`#foo` a valid preprocessing directive.
+
+The set of valid directive names is fixed. Programs cannot define new
+preprocessing directives.
+
+Some directives require arguments; these make up the rest of the
+directive line and must be separated from the directive name by
+whitespace. For example, :samp:`#define` must be followed by a macro
+name and the intended expansion of the macro.
+
+A preprocessing directive cannot cover more than one line. The line
+may, however, be continued with backslash-newline, or by a block comment
+which extends past the end of the line. In either case, when the
+directive is processed, the continuations have already been merged with
+the first line to make one long line.
\ No newline at end of file
diff --git a/gcc/doc/cpp/tokenization.rst b/gcc/doc/cpp/tokenization.rst
new file mode 100644
index 00000000000..62089b24780
--- /dev/null
+++ b/gcc/doc/cpp/tokenization.rst
@@ -0,0 +1,182 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _tokenization:
+
+Tokenization
+************
+
+.. index:: tokens
+
+.. index:: preprocessing tokens
+
+After the textual transformations are finished, the input file is
+converted into a sequence of :dfn:`preprocessing tokens`. These mostly
+correspond to the syntactic tokens used by the C compiler, but there are
+a few differences. White space separates tokens; it is not itself a
+token of any kind. Tokens do not have to be separated by white space,
+but it is often necessary to avoid ambiguities.
+
+When faced with a sequence of characters that has more than one possible
+tokenization, the preprocessor is greedy. It always makes each token,
+starting from the left, as big as possible before moving on to the next
+token. For instance, ``a+++++b`` is interpreted as
+``a ++ ++ + b``, not as ``a ++ + ++ b``, even though the
+latter tokenization could be part of a valid C program and the former
+could not.
+
+Once the input file is broken into tokens, the token boundaries never
+change, except when the :samp:`##` preprocessing operator is used to paste
+tokens together. See :ref:`concatenation`. For example,
+
+.. code-block::
+
+ #define foo() bar
+ foo()baz
+ → bar baz
+ not
+ → barbaz
+
+The compiler does not re-tokenize the preprocessor's output. Each
+preprocessing token becomes one compiler token.
+
+.. index:: identifiers
+
+Preprocessing tokens fall into five broad classes: identifiers,
+preprocessing numbers, string literals, punctuators, and other. An
+:dfn:`identifier` is the same as an identifier in C: any sequence of
+letters, digits, or underscores, which begins with a letter or
+underscore. Keywords of C have no significance to the preprocessor;
+they are ordinary identifiers. You can define a macro whose name is a
+keyword, for instance. The only identifier which can be considered a
+preprocessing keyword is ``defined``. See :ref:`defined`.
+
+This is mostly true of other languages which use the C preprocessor.
+However, a few of the keywords of C++ are significant even in the
+preprocessor. See :ref:`c++-named-operators`.
+
+In the 1999 C standard, identifiers may contain letters which are not
+part of the 'basic source character set', at the implementation's
+discretion (such as accented Latin letters, Greek letters, or Chinese
+ideograms). This may be done with an extended character set, or the
+:samp:`\\u` and :samp:`\\U` escape sequences.
+
+As an extension, GCC treats :samp:`$` as a letter. This is for
+compatibility with some systems, such as VMS, where :samp:`$` is commonly
+used in system-defined function and object names. :samp:`$` is not a
+letter in strictly conforming mode, or if you specify the :option:`-$`
+option. See :ref:`invocation`.
+
+.. index:: numbers
+
+.. index:: preprocessing numbers
+
+A :dfn:`preprocessing number` has a rather bizarre definition. The
+category includes all the normal integer and floating point constants
+one expects of C, but also a number of other things one might not
+initially recognize as a number. Formally, preprocessing numbers begin
+with an optional period, a required decimal digit, and then continue
+with any sequence of letters, digits, underscores, periods, and
+exponents. Exponents are the two-character sequences :samp:`e+`,
+:samp:`e-`, :samp:`E+`, :samp:`E-`, :samp:`p+`, :samp:`p-`, :samp:`P+`, and
+:samp:`P-`. (The exponents that begin with :samp:`p` or :samp:`P` are
+used for hexadecimal floating-point constants.)
+
+The purpose of this unusual definition is to isolate the preprocessor
+from the full complexity of numeric constants. It does not have to
+distinguish between lexically valid and invalid floating-point numbers,
+which is complicated. The definition also permits you to split an
+identifier at any position and get exactly two tokens, which can then be
+pasted back together with the :samp:`##` operator.
+
+It's possible for preprocessing numbers to cause programs to be
+misinterpreted. For example, ``0xE+12`` is a preprocessing number
+which does not translate to any valid numeric constant, therefore a
+syntax error. It does not mean ``0xE + 12``, which is what you
+might have intended.
+
+.. index:: string literals
+
+.. index:: string constants
+
+.. index:: character constants
+
+.. index:: header file names
+
+.. the @: prevents makeinfo from turning '' into ".
+
+:dfn:`String literals` are string constants, character constants, and
+header file names (the argument of :samp:`#include`) [#f1]_.
+
+String constants and character
+constants are straightforward: ``"..."`` or ``'...'``. In
+either case embedded quotes should be escaped with a backslash:
+``'\''`` is the character constant for :samp:`'`. There is no limit on
+the length of a character constant, but the value of a character
+constant that contains more than one character is
+implementation-defined. See :ref:`implementation-details`.
+
+Header file names either look like string constants, ``"..."``, or are
+written with angle brackets instead, ``<...>``. In either case,
+backslash is an ordinary character. There is no way to escape the
+closing quote or angle bracket. The preprocessor looks for the header
+file in different places depending on which form you use. See :ref:`include-operation`.
+
+No string literal may extend past the end of a line. You may use continued
+lines instead, or string constant concatenation.
+
+.. index:: punctuators
+
+.. index:: digraphs
+
+.. index:: alternative tokens
+
+:dfn:`Punctuators` are all the usual bits of punctuation which are
+meaningful to C and C++. All but three of the punctuation characters in
+ASCII are C punctuators. The exceptions are :samp:`@`, :samp:`$`, and
+:samp:`\``. In addition, all the two- and three-character operators are
+punctuators. There are also six :dfn:`digraphs`, which the C++ standard
+calls :dfn:`alternative tokens`, which are merely alternate ways to spell
+other punctuators. This is a second attempt to work around missing
+punctuation in obsolete systems. It has no negative side effects,
+unlike trigraphs, but does not cover as much ground. The digraphs and
+their corresponding normal punctuators are:
+
+.. code-block::
+
+ Digraph: <% %> <: :> %: %:%:
+ Punctuator: { } [ ] # ##
+
+.. index:: other tokens
+
+Any other single byte is considered 'other' and passed on to the
+preprocessor's output unchanged. The C compiler will almost certainly
+reject source code containing 'other' tokens. In ASCII, the only
+'other' characters are :samp:`@`, :samp:`$`, :samp:`\``, and control
+characters other than NUL (all bits zero). (Note that :samp:`$` is
+normally considered a letter.) All bytes with the high bit set
+(numeric range 0x7F--0xFF) that were not succesfully interpreted as
+part of an extended character in the input encoding are also 'other'
+in the present implementation.
+
+NUL is a special case because of the high probability that its
+appearance is accidental, and because it may be invisible to the user
+(many terminals do not display NUL at all). Within comments, NULs are
+silently ignored, just as any other character would be. In running
+text, NUL is considered white space. For example, these two directives
+have the same meaning.
+
+.. code-block:: c++
+
+ #define X^@1
+ #define X 1
+
+(where :samp:`^@` is ASCII NUL). Within string or character constants,
+NULs are preserved. In the latter two cases the preprocessor emits a
+warning message.
+
+.. [#f1] The C
+ standard uses the term :dfn:`string literal` to refer only to what we are
+ calling :dfn:`string constants`.
\ No newline at end of file
diff --git a/gcc/doc/cpp/traditional-lexical-analysis.rst b/gcc/doc/cpp/traditional-lexical-analysis.rst
new file mode 100644
index 00000000000..7887526a899
--- /dev/null
+++ b/gcc/doc/cpp/traditional-lexical-analysis.rst
@@ -0,0 +1,74 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _traditional-lexical-analysis:
+
+Tradit[...]
[diff truncated at 524288 bytes]
^ permalink raw reply [flat|nested] 2+ messages in thread
* [gcc(refs/users/marxin/heads/sphinx-v2)] Add RST files with config files.
@ 2021-06-23 10:21 Martin Liska
0 siblings, 0 replies; 2+ messages in thread
From: Martin Liska @ 2021-06-23 10:21 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:ef7c93748c1e1a234e7f4d251ddf429cd3ddd45e
commit ef7c93748c1e1a234e7f4d251ddf429cd3ddd45e
Author: Martin Liska <mliska@suse.cz>
Date: Wed Jun 23 11:24:27 2021 +0200
Add RST files with config files.
Diff:
---
doc/Makefile | 97 +
doc/baseconf.py | 103 +
doc/bsd.rst | 39 +
doc/contrib.rst | 1277 ++++++
doc/contribute.rst | 26 +
doc/copyright.rst | 25 +
doc/cppdiropts.rst | 215 +
doc/cppenv.rst | 97 +
doc/cppopts.rst | 559 +++
doc/cppwarnopts.rst | 4 +
doc/funding.rst | 47 +
doc/gnu.rst | 24 +
doc/gnu_free_documentation_license.rst | 463 ++
doc/gpl-3.0.rst | 707 +++
doc/lgpl-2.1.rst | 512 +++
doc/md.rst | 3272 ++++++++++++++
gcc/doc/cpp/character-sets.rst | 56 +
gcc/doc/cpp/conditional-syntax.rst | 413 ++
gcc/doc/cpp/conditional-uses.rst | 32 +
gcc/doc/cpp/conditionals.rst | 44 +
gcc/doc/cpp/conf.py | 29 +
gcc/doc/cpp/copyright.rst | 1 +
gcc/doc/cpp/deleted-code.rst | 34 +
gcc/doc/cpp/diagnostics.rst | 57 +
gcc/doc/cpp/environment-variables.rst | 26 +
gcc/doc/cpp/gnu-free-documentation-license.rst | 6 +
| 57 +
.../alternatives-to-wrapper-#ifndef.rst | 40 +
| 88 +
| 67 +
| 42 +
| 58 +
| 53 +
| 41 +
| 62 +
gcc/doc/cpp/implementation-defined-behavior.rst | 99 +
gcc/doc/cpp/implementation-details.rst | 23 +
gcc/doc/cpp/implementation-limits.rst | 68 +
gcc/doc/cpp/index.rst | 34 +
gcc/doc/cpp/initial-processing.rst | 174 +
gcc/doc/cpp/invocation.rst | 85 +
gcc/doc/cpp/line-control.rst | 55 +
gcc/doc/cpp/macros.rst | 37 +
gcc/doc/cpp/macros/concatenation.rst | 91 +
.../macros/directives-within-macro-arguments.rst | 39 +
gcc/doc/cpp/macros/function-like-macros.rst | 55 +
gcc/doc/cpp/macros/macro-arguments.rst | 116 +
gcc/doc/cpp/macros/macro-pitfalls.rst | 457 ++
gcc/doc/cpp/macros/object-like-macros.rst | 130 +
gcc/doc/cpp/macros/predefined-macros.rst | 658 +++
gcc/doc/cpp/macros/stringizing.rst | 88 +
.../macros/undefining-and-redefining-macros.rst | 71 +
gcc/doc/cpp/macros/variadic-macros.rst | 145 +
gcc/doc/cpp/obsolete-features.rst | 100 +
gcc/doc/cpp/option-index.rst | 6 +
gcc/doc/cpp/other-directives.rst | 32 +
gcc/doc/cpp/overview.rst | 66 +
gcc/doc/cpp/pragmas.rst | 121 +
gcc/doc/cpp/preprocessor-output.rst | 86 +
gcc/doc/cpp/the-preprocessing-language.rst | 75 +
gcc/doc/cpp/tokenization.rst | 182 +
gcc/doc/cpp/traditional-lexical-analysis.rst | 74 +
gcc/doc/cpp/traditional-macros.rst | 99 +
gcc/doc/cpp/traditional-miscellany.rst | 30 +
gcc/doc/cpp/traditional-mode.rst | 35 +
gcc/doc/cpp/traditional-warnings.rst | 49 +
gcc/doc/cppinternals/conf.py | 23 +
gcc/doc/cppinternals/copyright.rst | 1 +
gcc/doc/cppinternals/cppinternals.rst | 435 ++
gcc/doc/cppinternals/cpplib.rst | 29 +
gcc/doc/cppinternals/files.rst | 70 +
gcc/doc/cppinternals/index.rst | 18 +
gcc/doc/cppinternals/indices-and-tables.rst | 6 +
.../internal-representation-of-macros.rst | 27 +
.../cppinternals/just-which-line-number-anyway.rst | 62 +
gcc/doc/cppinternals/lexing-a-line.rst | 91 +
gcc/doc/cppinternals/lexing-a-token.rst | 177 +
...-a-function-like-macros-opening-parenthesis.rst | 24 +
gcc/doc/cppinternals/macro-expansion-overview.rst | 51 +
...king-tokens-ineligible-for-future-expansion.rst | 24 +
gcc/doc/cppinternals/overview.rst | 24 +
.../representation-of-line-numbers.rst | 32 +
...g-the-replacement-list-for-macros-to-expand.rst | 57 +
gcc/doc/gcc/binary-compatibility.rst | 155 +
.../gcc/c++-implementation-defined-behavior.rst | 35 +
gcc/doc/gcc/c-implementation-defined-behavior.rst | 48 +
.../architecture.rst | 47 +
.../arrays-and-pointers.rst | 46 +
.../characters.rst | 101 +
.../declarators.rst | 14 +
.../environment.rst | 19 +
.../floating-point.rst | 87 +
.../c-implementation-defined-behavior/hints.rst | 35 +
.../identifiers.rst | 29 +
.../c-implementation-defined-behavior/integers.rst | 66 +
.../library-functions.rst | 19 +
.../locale-specific-behavior.rst | 12 +
.../preprocessing-directives.rst | 56 +
.../qualifiers.rst | 53 +
.../statements.rst | 14 +
...ructures-unions-enumerations-and-bit-fields.rst | 78 +
.../translation.rst | 21 +
gcc/doc/gcc/conditionally-supported-behavior.rst | 20 +
gcc/doc/gcc/conf.py | 36 +
gcc/doc/gcc/contributing-to-gcc-development.rst | 6 +
gcc/doc/gcc/contributors-to-gcc.rst | 6 +
gcc/doc/gcc/copyright.rst | 1 +
gcc/doc/gcc/exception-handling.rst | 15 +
gcc/doc/gcc/extensions-to-the-c++-language.rst | 36 +
.../backwards-compatibility.rst | 32 +
.../c++-concepts.rst | 44 +
.../c++-interface-and-implementation-pragmas.rst | 107 +
...cific-variable-function-and-type-attributes.rst | 99 +
.../deprecated-features.rst | 43 +
...ter-from-a-bound-pointer-to-member-function.rst | 52 +
.../function-multiversioning.rst | 65 +
.../restricting-pointer-aliasing.rst | 56 +
.../extensions-to-the-c++-language/type-traits.rst | 159 +
.../vague-linkage.rst | 86 +
.../when-is-a-volatile-c++-object-accessed.rst | 64 +
.../wheres-the-template.rst | 131 +
.../gcc/extensions-to-the-c-language-family.rst | 97 +
.../128-bit-integers.rst | 18 +
.../additional-floating-types.rst | 100 +
.../alternate-keywords.rst | 50 +
.../an-inline-function-is-as-fast-as-a-macro.rst | 142 +
.../arithmetic-on-void-and-function-pointers.rst | 29 +
.../arrays-of-length-zero.rst | 117 +
.../arrays-of-variable-length.rst | 107 +
.../attribute-syntax.rst | 259 ++
.../binary-constants-using-the-0b-prefix.rst | 29 +
...ns-for-memory-model-aware-atomic-operations.rst | 302 ++
...o-perform-arithmetic-with-overflow-checking.rst | 122 +
| 22 +
.../case-ranges.rst | 43 +
.../cast-to-a-union-type.rst | 71 +
.../complex-numbers.rst | 72 +
.../compound-literals.rst | 112 +
.../conditionals-with-omitted-operands.rst | 49 +
.../constructing-function-calls.rst | 127 +
.../decimal-floating-types.rst | 65 +
.../declaring-attributes-of-functions.rst | 115 +
.../aarch64-function-attributes.rst | 192 +
.../amd-gcn-function-attributes.rst | 93 +
.../arc-function-attributes.rst | 94 +
.../arm-function-attributes.rst | 172 +
.../avr-function-attributes.rst | 122 +
.../blackfin-function-attributes.rst | 105 +
.../bpf-function-attributes.rst | 24 +
.../c-sky-function-attributes.rst | 39 +
.../common-function-attributes.rst | 1811 ++++++++
.../cr16-function-attributes.rst | 20 +
.../epiphany-function-attributes.rst | 86 +
.../h8-300-function-attributes.rst | 41 +
.../ia-64-function-attributes.rst | 36 +
.../m32c-function-attributes.rst | 75 +
.../m32r-d-function-attributes.rst | 44 +
.../m68k-function-attributes.rst | 32 +
.../mcore-function-attributes.rst | 24 +
.../mep-function-attributes.rst | 53 +
.../microblaze-function-attributes.rst | 50 +
.../microsoft-windows-function-attributes.rst | 108 +
.../mips-function-attributes.rst | 146 +
.../msp430-function-attributes.rst | 107 +
.../nds32-function-attributes.rst | 100 +
.../nios-ii-function-attributes.rst | 44 +
.../nvidia-ptx-function-attributes.rst | 22 +
.../powerpc-function-attributes.rst | 229 +
.../risc-v-function-attributes.rst | 43 +
.../rl78-function-attributes.rst | 39 +
.../rx-function-attributes.rst | 75 +
.../s-390-function-attributes.rst | 52 +
.../sh-function-attributes.rst | 103 +
.../symbian-os-function-attributes.rst | 12 +
.../v850-function-attributes.rst | 22 +
.../visium-function-attributes.rst | 20 +
.../x86-function-attributes.rst | 983 ++++
.../xstormy16-function-attributes.rst | 20 +
.../designated-initializers.rst | 153 +
...e-alignment-of-functions-types-or-variables.rst | 48 +
.../dollar-signs-in-identifier-names.rst | 20 +
.../double-word-integers.rst | 43 +
.../enumerator-attributes.rst | 45 +
.../fixed-point-types.rst | 198 +
...ecks-specific-to-particular-target-machines.rst | 47 +
.../function-names-as-strings.rst | 75 +
...g-the-return-or-frame-address-of-a-function.rst | 97 +
.../half-precision-floating-point.rst | 60 +
.../hex-floats.rst | 30 +
...w-to-use-inline-assembly-language-in-c-code.rst | 1865 ++++++++
.../incomplete-enum-types.rst | 23 +
.../label-attributes.rst | 65 +
.../labels-as-values.rst | 93 +
...built-in-functions-for-atomic-memory-access.rst | 185 +
.../locally-declared-labels.rst | 84 +
.../macros-with-a-variable-number-of-arguments.rst | 74 +
.../mixed-declarations-labels-and-code.rst | 31 +
.../named-address-spaces.rst | 231 +
.../nested-functions.rst | 136 +
.../non-constant-initializers.rst | 25 +
.../non-lvalue-arrays-may-have-subscripts.rst | 34 +
.../nonlocal-gotos.rst | 62 +
.../object-size-checking-built-in-functions.rst | 167 +
.../other-built-in-functions-provided-by-gcc.rst | 2018 +++++++++
.../pointer-arguments-in-variadic-functions.rst | 24 +
...-to-arrays-with-qualifiers-work-as-expected.rst | 29 +
.../pragmas-accepted-by-gcc.rst | 719 +++
...ototypes-and-old-style-function-definitions.rst | 67 +
.../referring-to-a-type-with-typeof.rst | 149 +
.../slightly-looser-rules-for-escaped-newlines.rst | 25 +
.../specifying-attributes-of-types.rst | 704 +++
.../specifying-attributes-of-variables.rst | 1123 +++++
.../statement-attributes.rst | 46 +
.../statements-and-declarations-in-expressions.rst | 170 +
.../structures-with-no-members.rst | 24 +
.../support-for-offsetof.rst | 34 +
.../target-builtins.rst | 55 +
.../target-builtins/aarch64-built-in-functions.rst | 24 +
.../target-builtins/alpha-built-in-functions.rst | 88 +
.../altera-nios-ii-built-in-functions.rst | 118 +
.../target-builtins/arc-built-in-functions.rst | 232 +
.../arc-simd-built-in-functions.rst | 243 +
.../arm-armv8-m-security-extensions.rst | 35 +
.../arm-c-language-extensions-acle.rst | 30 +
...loating-point-status-and-control-intrinsics.rst | 17 +
.../arm-iwmmxt-built-in-functions.rst | 159 +
.../target-builtins/avr-built-in-functions.rst | 99 +
.../basic-powerpc-built-in-functions.rst | 728 +++
.../blackfin-built-in-functions.rst | 20 +
.../target-builtins/bpf-built-in-functions.rst | 23 +
.../target-builtins/fr-v-built-in-functions.rst | 231 +
.../mips-dsp-built-in-functions.rst | 299 ++
.../mips-loongson-built-in-functions.rst | 423 ++
.../target-builtins/mips-paired-single-support.rst | 44 +
.../mips-simd-architecture-msa-support.rst | 812 ++++
.../target-builtins/msp430-built-in-functions.rst | 33 +
.../target-builtins/nds32-built-in-functions.rst | 44 +
.../other-mips-built-in-functions.rst | 24 +
.../picochip-built-in-functions.rst | 39 +
.../powerpc-altivec-vsx-built-in-functions.rst | 1871 ++++++++
.../powerpc-atomic-memory-operation-functions.rst | 68 +
...are-transactional-memory-built-in-functions.rst | 226 +
...c-matrix-multiply-assist-built-in-functions.rst | 101 +
.../target-builtins/pru-built-in-functions.rst | 31 +
.../target-builtins/risc-v-built-in-functions.rst | 16 +
.../target-builtins/rx-built-in-functions.rst | 122 +
.../s-390-system-z-built-in-functions.rst | 121 +
.../target-builtins/sh-built-in-functions.rst | 50 +
.../sparc-vis-built-in-functions.rst | 226 +
.../target-builtins/ti-c6x-built-in-functions.rst | 43 +
.../target-builtins/tile-gx-built-in-functions.rst | 37 +
.../target-builtins/tilepro-built-in-functions.rst | 39 +
.../target-builtins/x86-built-in-functions.rst | 1643 +++++++
.../x86-control-flow-protection-intrinsics.rst | 50 +
.../x86-transactional-memory-intrinsics.rst | 102 +
.../the-character-esc-in-constants.rst | 12 +
.../thread-local-storage.rst | 223 +
.../unnamed-structure-and-union-fields.rst | 88 +
...tor-instructions-through-built-in-functions.rst | 285 ++
.../when-is-a-volatile-object-accessed.rst | 92 +
...y-model-extensions-for-transactional-memory.rst | 38 +
gcc/doc/gcc/funding.rst | 6 +
gcc/doc/gcc/gcc-command-options.rst | 71 +
gcc/doc/gcc/gcc-command-options/c++-modules.rst | 361 ++
.../gcc-command-options/compiling-c++-programs.rst | 46 +
gcc/doc/gcc/gcc-command-options/description.rst | 83 +
.../environment-variables-affecting-gcc.rst | 163 +
.../gcc-command-options/gcc-developer-options.rst | 1155 +++++
.../machine-dependent-options.rst | 100 +
.../machine-dependent-options/aarch64-options.rst | 482 ++
.../adapteva-epiphany-options.rst | 161 +
.../machine-dependent-options/amd-gcn-options.rst | 37 +
.../machine-dependent-options/arc-options.rst | 749 ++++
.../machine-dependent-options/arm-options.rst | 1010 +++++
.../machine-dependent-options/avr-options.rst | 640 +++
.../machine-dependent-options/blackfin-options.rst | 225 +
.../machine-dependent-options/c-sky-options.rst | 191 +
.../machine-dependent-options/c6x-options.rst | 53 +
.../machine-dependent-options/cr16-options.rst | 42 +
.../machine-dependent-options/cris-options.rst | 113 +
.../machine-dependent-options/darwin-options.rst | 166 +
.../dec-alpha-options.rst | 272 ++
.../machine-dependent-options/ebpf-options.rst | 45 +
.../machine-dependent-options/fr30-options.rst | 25 +
.../machine-dependent-options/frv-options.rst | 277 ++
.../machine-dependent-options/ft32-options.rst | 42 +
.../gnu-linux-options.rst | 54 +
.../machine-dependent-options/h8-300-options.rst | 61 +
.../machine-dependent-options/hppa-options.rst | 243 +
.../machine-dependent-options/ia-64-options.rst | 259 ++
.../ibm-rs-6000-and-powerpc-options.rst | 1011 +++++
.../machine-dependent-options/lm32-options.rst | 33 +
.../machine-dependent-options/m32c-options.rst | 36 +
.../machine-dependent-options/m32r-d-options.rst | 135 +
.../machine-dependent-options/m680x0-options.rst | 375 ++
.../machine-dependent-options/mcore-options.rst | 64 +
.../machine-dependent-options/mep-options.rst | 165 +
.../microblaze-options.rst | 118 +
.../machine-dependent-options/mips-options.rst | 974 ++++
.../machine-dependent-options/mmix-options.rst | 73 +
.../machine-dependent-options/mn10300-options.rst | 91 +
.../machine-dependent-options/moxie-options.rst | 29 +
.../machine-dependent-options/msp430-options.rst | 184 +
.../machine-dependent-options/nds32-options.rst | 114 +
.../machine-dependent-options/nios-ii-options.rst | 365 ++
.../nvidia-ptx-options.rst | 73 +
.../machine-dependent-options/openrisc-options.rst | 84 +
.../options-for-system-v.rst | 41 +
.../machine-dependent-options/pdp-11-options.rst | 71 +
.../machine-dependent-options/picochip-options.rst | 53 +
.../machine-dependent-options/powerpc-options.rst | 13 +
.../machine-dependent-options/pru-options.rst | 61 +
.../machine-dependent-options/risc-v-options.rst | 192 +
.../machine-dependent-options/rl78-options.rst | 89 +
.../machine-dependent-options/rx-options.rst | 203 +
.../s-390-and-zseries-options.rst | 241 +
.../machine-dependent-options/score-options.rst | 49 +
.../machine-dependent-options/sh-options.rst | 442 ++
.../solaris-2-options.rst | 40 +
.../machine-dependent-options/sparc-options.rst | 385 ++
.../machine-dependent-options/tile-gx-options.rst | 39 +
.../machine-dependent-options/tilepro-options.rst | 24 +
.../machine-dependent-options/v850-options.rst | 205 +
.../machine-dependent-options/vax-options.rst | 28 +
.../machine-dependent-options/visium-options.rst | 71 +
.../machine-dependent-options/vms-options.rst | 36 +
.../machine-dependent-options/vxworks-options.rst | 43 +
.../machine-dependent-options/x86-options.rst | 1496 +++++++
.../x86-windows-options.rst | 95 +
.../xstormy16-options.rst | 17 +
.../machine-dependent-options/xtensa-options.rst | 128 +
.../machine-dependent-options/zseries-options.rst | 13 +
gcc/doc/gcc/gcc-command-options/option-summary.rst | 1340 ++++++
.../options-controlling-c++-dialect.rst | 1935 ++++++++
.../options-controlling-c-dialect.rst | 496 +++
...ling-objective-c-and-objective-c++-dialects.rst | 319 ++
.../options-controlling-the-kind-of-output.rst | 729 +++
.../options-controlling-the-preprocessor.rst | 81 +
.../options-for-code-generation-conventions.rst | 714 +++
.../options-for-debugging-your-program.rst | 475 ++
.../options-for-directory-search.rst | 106 +
.../gcc-command-options/options-for-linking.rst | 411 ++
.../options-that-control-optimization.rst | 4678 ++++++++++++++++++++
.../options-that-control-static-analysis.rst | 563 +++
...s-to-control-diagnostic-messages-formatting.rst | 831 ++++
.../options-to-request-or-suppress-warnings.rst | 4504 +++++++++++++++++++
.../passing-options-to-the-assembler.rst | 27 +
.../program-instrumentation-options.rst | 941 ++++
...bprocesses-and-the-switches-to-pass-to-them.rst | 688 +++
| 136 +
gcc/doc/gcc/gcc.rst | 47 +
gcc/doc/gcc/gcov-dump.rst | 52 +
gcc/doc/gcc/gcov-tool.rst | 154 +
gcc/doc/gcc/gcov.rst | 25 +
.../gcov/brief-description-of-gcov-data-files.rst | 33 +
...-file-relocation-to-support-cross-profiling.rst | 43 +
gcc/doc/gcc/gcov/introduction-to-gcov.rst | 62 +
gcc/doc/gcc/gcov/invoking-gcov.rst | 656 +++
.../gcc/gcov/using-gcov-with-gcc-optimization.rst | 86 +
gcc/doc/gcc/general-public-license-3.rst | 6 +
gcc/doc/gcc/gnu-free-documentation-license.rst | 6 +
gcc/doc/gcc/gnu-objective-c-features.rst | 29 +
.../compatibilityalias.rst | 28 +
.../constant-string-objects.rst | 66 +
.../gcc/gnu-objective-c-features/exceptions.rst | 81 +
.../gnu-objective-c-features/fast-enumeration.rst | 223 +
.../garbage-collection.rst | 83 +
.../gnu-objective-c-runtime-api.rst | 100 +
.../load-executing-code-before-main.rst | 141 +
.../messaging-with-the-gnu-objective-c-runtime.rst | 145 +
.../gnu-objective-c-features/synchronization.rst | 38 +
.../gcc/gnu-objective-c-features/type-encoding.rst | 242 +
gcc/doc/gcc/gnu.rst | 1 +
gcc/doc/gcc/have-you-found-a-bug.rst | 70 +
gcc/doc/gcc/how-and-where-to-report-bugs.rst | 13 +
gcc/doc/gcc/how-to-get-help-with-gcc.rst | 26 +
gcc/doc/gcc/index.rst | 39 +
gcc/doc/gcc/known-causes-of-trouble-with-gcc.rst | 36 +
.../actual-bugs-we-havent-fixed-yet.rst | 14 +
.../certain-changes-we-dont-want-to-make.rst | 242 +
.../common-misunderstandings-with-gnu-c.rst | 311 ++
.../disappointments-and-misunderstandings.rst | 105 +
| 39 +
.../incompatibilities-of-gcc.rst | 255 ++
.../interoperation.rst | 153 +
.../standard-libraries.rst | 33 +
.../warning-messages-and-error-messages.rst | 52 +
.../gcc/language-standards-supported-by-gcc.rst | 23 +
.../c++-language.rst | 71 +
.../c-language.rst | 232 +
.../d-language.rst | 11 +
.../go-language.rst | 10 +
.../objective-c-and-objective-c++-languages.rst | 64 +
.../references-for-other-languages.rst | 13 +
gcc/doc/gcc/lto-dump.rst | 92 +
gcc/doc/gcc/option-index.rst | 11 +
.../gcc/programming-languages-supported-by-gcc.rst | 82 +
gcc/doc/gcc/reporting-bugs.rst | 25 +
.../analysis-and-optimization-of-gimple-tuples.rst | 46 +
.../alias-analysis.rst | 108 +
.../annotations.rst | 17 +
.../memory-model.rst | 34 +
.../ssa-operands.rst | 396 ++
.../static-single-assignment.rst | 264 ++
.../analysis-and-representation-of-loops.rst | 27 +
.../data-dependency-analysis.rst | 135 +
.../iv-analysis-on-rtl.rst | 55 +
.../loop-closed-ssa-form.rst | 49 +
.../loop-manipulation.rst | 58 +
.../loop-querying.rst | 81 +
.../loop-representation.rst | 138 +
.../number-of-iterations-analysis.rst | 85 +
.../scalar-evolutions.rst | 73 +
gcc/doc/gccint/analyzer-internals.rst | 421 ++
gcc/doc/gccint/collect2.rst | 79 +
gcc/doc/gccint/conf.py | 23 +
gcc/doc/gccint/contributing-to-gcc-development.rst | 6 +
gcc/doc/gccint/contributors-to-gcc.rst | 6 +
gcc/doc/gccint/control-flow-graph.rst | 45 +
gcc/doc/gccint/control-flow-graph/basic-blocks.rst | 149 +
gcc/doc/gccint/control-flow-graph/edges.rst | 251 ++
.../control-flow-graph/liveness-information.rst | 53 +
.../control-flow-graph/maintaining-the-cfg.rst | 155 +
.../control-flow-graph/profile-information.rst | 116 +
gcc/doc/gccint/copyright.rst | 1 +
gcc/doc/gccint/debugging-the-analyzer.rst | 110 +
gcc/doc/gccint/funding.rst | 6 +
gcc/doc/gccint/gcc-and-portability.rst | 47 +
gcc/doc/gccint/general-public-license-3.rst | 6 +
gcc/doc/gccint/generic.rst | 51 +
gcc/doc/gccint/generic/attributes-in-trees.rst | 39 +
gcc/doc/gccint/generic/c-and-c++-trees.rst | 1026 +++++
gcc/doc/gccint/generic/declarations.rst | 384 ++
gcc/doc/gccint/generic/deficiencies.rst | 18 +
gcc/doc/gccint/generic/expressions.rst | 1142 +++++
gcc/doc/gccint/generic/functions.rst | 228 +
.../gccint/generic/language-dependent-trees.rst | 25 +
gcc/doc/gccint/generic/overview.rst | 239 +
gcc/doc/gccint/generic/statements.rst | 562 +++
gcc/doc/gccint/generic/types.rst | 387 ++
gcc/doc/gccint/gimple-api.rst | 58 +
gcc/doc/gccint/gimple.rst | 88 +
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.../class-hierarchy-of-gimple-statements.rst | 150 +
gcc/doc/gccint/gimple/exception-handling.rst | 46 +
gcc/doc/gccint/gimple/gimple-instruction-set.rst | 46 +
gcc/doc/gccint/gimple/gimple-sequences.rst | 94 +
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gcc/doc/gccint/gimple/operands.rst | 319 ++
gcc/doc/gccint/gimple/sequence-iterators.rst | 223 +
.../gimple/statement-and-operand-traversals.rst | 66 +
gcc/doc/gccint/gimple/temporaries.rst | 42 +
gcc/doc/gccint/gimple/tuple-representation.rst | 211 +
gcc/doc/gccint/gimple/tuple-specific-accessors.rst | 44 +
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.../tuple-specific-accessors/gimpleompordered.rst | 16 +
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.../tuple-specific-accessors/gimpleswitch.rst | 52 +
.../gimple/tuple-specific-accessors/gimpletry.rst | 51 +
.../gimplewithcleanupexpr.rst | 30 +
gcc/doc/gccint/gnu-free-documentation-license.rst | 6 +
gcc/doc/gccint/guidelines-for-diagnostics.rst | 614 +++
gcc/doc/gccint/guidelines-for-options.rst | 17 +
gcc/doc/gccint/host-common.rst | 59 +
gcc/doc/gccint/host-configuration.rst | 32 +
gcc/doc/gccint/host-filesystem.rst | 105 +
gcc/doc/gccint/host-makefile-fragments.rst | 16 +
gcc/doc/gccint/host-misc.rst | 71 +
gcc/doc/gccint/index.rst | 74 +
gcc/doc/gccint/interfacing-to-gcc-output.rst | 85 +
gcc/doc/gccint/language-front-ends-in-gcc.rst | 39 +
gcc/doc/gccint/link-time-optimization.rst | 34 +
.../link-time-optimization/design-overview.rst | 124 +
.../internal-flags-controlling-lto1.rst | 44 +
.../link-time-optimization/lto-file-sections.rst | 110 +
.../using-summary-information-in-ipa-passes.rst | 206 +
...tions-linker-plugin-and-symbol-visibilities.rst | 91 +
gcc/doc/gccint/machine-descriptions.rst | 49 +
.../c-statements-for-assembler-output.rst | 128 +
.../canonicalization-of-instructions.rst | 169 +
.../machine-descriptions/conditional-execution.rst | 100 +
.../machine-descriptions/constant-definitions.rst | 185 +
.../defining-how-to-split-instructions.rst | 378 ++
.../defining-jump-instruction-patterns.rst | 39 +
.../defining-looping-instruction-patterns.rst | 136 +
.../defining-rtl-sequences-for-code-generation.rst | 211 +
.../everything-about-instruction-patterns.rst | 113 +
.../machine-descriptions/example-of-defineinsn.rst | 54 +
.../including-patterns-in-machine-descriptions.rst | 76 +
.../instruction-attributes.rst | 1360 ++++++
.../interdependence-of-patterns.rst | 45 +
gcc/doc/gccint/machine-descriptions/iterators.rst | 555 +++
.../machine-specific-peephole-optimizers.rst | 335 ++
.../machine-descriptions/operand-constraints.rst | 429 ++
.../output-templates-and-operand-substitution.rst | 107 +
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gcc/doc/gccint/machine-descriptions/predicates.rst | 361 ++
.../gccint/machine-descriptions/rtl-template.rst | 263 ++
.../rtl-templates-transformations.rst | 225 +
.../standard-pattern-names-for-generation.rst | 3514 +++++++++++++++
.../when-the-order-of-patterns-matters.rst | 31 +
gcc/doc/gccint/makefile-fragments.rst | 37 +
gcc/doc/gccint/match-and-simplify.rst | 34 +
.../memory-management-and-type-information.rst | 97 +
.../how-to-invoke-the-garbage-collector.rst | 35 +
.../marking-roots-for-the-garbage-collector.rst | 30 +
.../source-files-containing-type-information.rst | 63 +
.../support-for-inheritance.rst | 59 +
...pport-for-user-provided-gc-marking-routines.rst | 121 +
.../the-inside-of-a-gty.rst | 304 ++
.../troubleshooting-the-garbage-collector.rst | 29 +
gcc/doc/gccint/option-file-format.rst | 149 +
gcc/doc/gccint/option-index.rst | 11 +
gcc/doc/gccint/option-properties.rst | 360 ++
gcc/doc/gccint/option-specification-files.rst | 23 +
.../gccint/passes-and-files-of-the-compiler.rst | 33 +
.../gimplification-pass.rst | 50 +
.../inter-procedural-optimization-passes.rst | 271 ++
.../optimization-info.rst | 262 ++
.../parsing-pass.rst | 96 +
.../pass-manager.rst | 42 +
.../rtl-passes.rst | 279 ++
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gcc/doc/gccint/plugins.rst | 35 +
gcc/doc/gccint/plugins/building-gcc-plugins.rst | 101 +
.../controlling-which-passes-are-being-run.rst | 16 +
.../plugins/giving-information-about-a-plugin.rst | 24 +
.../interacting-with-the-gcc-garbage-collector.rst | 37 +
.../plugins/interacting-with-the-pass-manager.rst | 57 +
.../plugins/keeping-track-of-available-passes.rst | 17 +
gcc/doc/gccint/plugins/loading-plugins.rst | 31 +
gcc/doc/gccint/plugins/plugin-api.rst | 213 +
.../recording-information-about-pass-execution.rst | 20 +
.../registering-custom-attributes-or-pragmas.rst | 73 +
gcc/doc/gccint/rtl-representation.rst | 52 +
.../rtl-representation/access-to-operands.rst | 85 +
.../access-to-special-operands.rst | 192 +
.../assembler-instructions-as-expressions.rst | 47 +
gcc/doc/gccint/rtl-representation/bit-fields.rst | 50 +
.../rtl-representation/comparison-operations.rst | 140 +
.../constant-expression-types.rst | 325 ++
gcc/doc/gccint/rtl-representation/conversions.rst | 154 +
gcc/doc/gccint/rtl-representation/declarations.rst | 31 +
.../embedded-side-effects-on-addresses.rst | 106 +
.../flags-in-an-rtl-expression.rst | 625 +++
gcc/doc/gccint/rtl-representation/insns.rst | 650 +++
.../gccint/rtl-representation/machine-modes.rst | 663 +++
.../on-the-side-ssa-form-for-rtl.rst | 774 ++++
gcc/doc/gccint/rtl-representation/reading-rtl.rst | 34 +
.../rtl-representation/registers-and-memory.rst | 471 ++
.../rtl-representation/rtl-classes-and-formats.rst | 198 +
.../rtl-expressions-for-arithmetic.rst | 434 ++
.../gccint/rtl-representation/rtl-object-types.rst | 102 +
.../rtl-representation-of-function-call-insns.rst | 76 +
.../rtl-representation/side-effect-expressions.rst | 380 ++
.../structure-sharing-assumptions.rst | 105 +
.../variable-location-debug-information-in-rtl.rst | 64 +
.../rtl-representation/vector-operations.rst | 60 +
.../sizes-and-offsets-as-runtime-invariants.rst | 53 +
.../alignment-of-polyints.rst | 82 +
.../arithmetic-on-polyints.rst | 178 +
.../comparisons-involving-polyint.rst | 321 ++
.../computing-bounds-on-polyints.rst | 34 +
.../consequences-of-using-polyint.rst | 55 +
.../converting-polyints.rst | 91 +
.../guidelines-for-using-polyint.rst | 123 +
.../miscellaneous-polyint-routines.rst | 16 +
.../overview-of-polyint.rst | 80 +
.../source-tree-structure-and-build-system.rst | 21 +
.../configure-terms-and-history.rst | 66 +
.../the-gcc-subdirectory.rst | 28 +
.../anatomy-of-a-language-front-end.rst | 286 ++
.../anatomy-of-a-target-back-end.rst | 116 +
.../build-system-in-the-gcc-directory.rst | 14 +
.../building-documentation.rst | 168 +
.../configuration-in-the-gcc-directory.rst | 128 +
| 49 +
...e-files-and-headers-under-the-gcc-directory.rst | 15 +
.../the-gcc-subdirectory/makefile-targets.rst | 192 +
.../the-gcc-subdirectory/subdirectories-of-gcc.rst | 56 +
.../top-level-source-directory.rst | 116 +
.../gccint/standard-header-file-directories.rst | 35 +
gcc/doc/gccint/static-analyzer.rst | 21 +
gcc/doc/gccint/target-macros.rst | 66 +
.../adding-support-for-named-address-spaces.rst | 163 +
gcc/doc/gccint/target-macros/addressing-modes.rst | 830 ++++
.../adjusting-the-instruction-scheduler.rst | 660 +++
.../gccint/target-macros/anchored-addresses.rst | 94 +
.../gccint/target-macros/c++-abi-parameters.rst | 164 +
.../gccint/target-macros/condition-code-status.rst | 212 +
.../controlling-debugging-information-format.rst | 490 ++
.../controlling-the-compilation-driver-gcc.rst | 484 ++
.../cross-compilation-and-floating-point.rst | 75 +
gcc/doc/gccint/target-macros/d-abi-parameters.rst | 107 +
...ning-coprocessor-specifics-for-mips-targets.rst | 35 +
...ata-structures-for-per-function-information.rst | 64 +
.../defining-target-specific-uses-of-attribute.rst | 284 ++
.../defining-the-output-assembler-language.rst | 27 +
.../assembler-commands-for-alignment.rst | 95 +
.../assembler-commands-for-exception-regions.rst | 188 +
.../how-initialization-functions-are-handled.rst | 130 +
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.../output-and-generation-of-labels.rst | 586 +++
.../output-of-assembler-instructions.rst | 255 ++
.../output-of-data.rst | 196 +
.../output-of-dispatch-tables.rst | 171 +
.../output-of-uninitialized-variables.rst | 105 +
.../the-overall-framework-of-an-assembler-file.rst | 287 ++
.../describing-relative-costs-of-operations.rst | 532 +++
...ividing-the-output-into-sections-texts-data.rst | 443 ++
gcc/doc/gccint/target-macros/emulating-tls.rst | 125 +
.../implementing-the-varargs-macros.rst | 237 +
.../implicit-calls-to-library-routines.rst | 147 +
.../layout-of-source-language-data-types.rst | 381 ++
.../target-macros/miscellaneous-parameters.rst | 1658 +++++++
.../target-macros/mode-switching-instructions.rst | 121 +
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.../target-macros/position-independent-code.rst | 55 +
gcc/doc/gccint/target-macros/register-classes.rst | 807 ++++
gcc/doc/gccint/target-macros/register-usage.rst | 595 +++
.../run-time-target-specification.rst | 259 ++
.../stack-layout-and-calling-conventions.rst | 35 +
.../basic-stack-layout.rst | 300 ++
.../caller-saves-register-allocation.rst | 21 +
.../eliminating-frame-pointer-and-arg-pointer.rst | 102 +
.../exception-handling-support.rst | 137 +
.../function-entry-and-exit.rst | 274 ++
.../generating-code-for-profiling.rst | 61 +
.../how-large-values-are-returned.rst | 138 +
.../how-scalar-function-values-are-returned.rst | 170 +
.../miscellaneous-register-hooks.rst | 26 +
.../passing-arguments-in-registers.rst | 643 +++
.../passing-function-arguments-on-the-stack.rst | 197 +
.../permitting-tail-calls.rst | 60 +
.../registers-that-address-the-stack-frame.rst | 202 +
.../shrink-wrapping-separate-components.rst | 93 +
.../specifying-how-stack-checking-is-done.rst | 118 +
.../stack-smashing-protection.rst | 75 +
gcc/doc/gccint/target-macros/storage-layout.rst | 722 +++
.../target-macros/support-for-nested-functions.rst | 228 +
.../target-macros/the-global-targetm-variable.rst | 67 +
gcc/doc/gccint/target-makefile-fragments.rst | 247 ++
gcc/doc/gccint/testsuites.rst | 29 +
.../gccint/testsuites/ada-language-testsuites.rst | 38 +
.../gccint/testsuites/c-language-testsuites.rst | 113 +
.../directives-used-within-dejagnu-tests.rst | 19 +
.../commands-for-use-in-dg-final.rst | 283 ++
.../features-for-dg-add-options.rst | 123 +
.../keywords-describing-target-attributes.rst | 1369 ++++++
.../selecting-targets-to-which-a-test-applies.rst | 106 +
.../syntax-and-descriptions-of-test-directives.rst | 311 ++
.../variants-of-dg-require-support.rst | 83 +
.../testsuites/idioms-used-in-testsuite-code.rst | 84 +
.../support-for-testing-binary-compatibility.rst | 109 +
.../gccint/testsuites/support-for-testing-gcov.rst | 72 +
.../support-for-testing-gimple-passes.rst | 55 +
...support-for-testing-link-time-optimizations.rst | 46 +
...-for-testing-profile-directed-optimizations.rst | 52 +
.../testsuites/support-for-testing-rtl-passes.rst | 48 +
...-for-torture-testing-using-multiple-options.rst | 52 +
.../gccint/the-gcc-low-level-runtime-library.rst | 49 +
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...utines-for-decimal-floating-point-emulation.rst | 470 ++
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.../routines-for-integer-arithmetic.rst | 218 +
gcc/doc/gccint/the-language.rst | 384 ++
gcc/doc/gccint/user-experience-guidelines.rst | 32 +
gcc/doc/install/binaries.rst | 61 +
gcc/doc/install/building.rst | 65 +
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gcc/doc/install/building/building-in-parallel.rst | 15 +
.../install/building/building-the-ada-compiler.rst | 9 +
.../building/building-with-profile-feedback.rst | 36 +
gcc/doc/install/conf.py | 23 +
gcc/doc/install/configuration.rst | 2055 +++++++++
gcc/doc/install/copyright.rst | 1 +
gcc/doc/install/downloading-gcc.rst | 46 +
gcc/doc/install/final-installation.rst | 136 +
gcc/doc/install/gnu-free-documentation-license.rst | 6 +
...-target-specific-installation-notes-for-gcc.rst | 1363 ++++++
...can-you-run-the-testsuite-on-selected-tests.rst | 46 +
gcc/doc/install/how-to-interpret-test-results.rst | 32 +
gcc/doc/install/index.rst | 26 +
gcc/doc/install/indices-and-tables.rst | 6 +
gcc/doc/install/installing-gcc.rst | 41 +
...ing-options-and-running-multiple-testsuites.rst | 74 +
gcc/doc/install/prerequisites.rst | 280 ++
gcc/doc/install/submitting-test-results.rst | 24 +
gcc/doc/install/testing.rst | 73 +
.../code-that-interacts-with-the-user.rst | 19 +
.../doc/gfc-internals/command-line-options.rst | 35 +
gcc/fortran/doc/gfc-internals/conf.py | 26 +
gcc/fortran/doc/gfc-internals/copyright.rst | 1 +
gcc/fortran/doc/gfc-internals/error-handling.rst | 79 +
.../doc/gfc-internals/frontend-data-structures.rst | 26 +
...-the-intermediate-language-for-later-stages.rst | 24 +
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gcc/fortran/doc/gfc-internals/gfccode.rst | 151 +
gcc/fortran/doc/gfc-internals/gfcexpr.rst | 162 +
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gcc/fortran/doc/gfc-internals/index.rst | 38 +
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gcc/fortran/doc/gfc-internals/introduction.rst | 22 +
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gcc/fortran/doc/gfortran/coarray-programming.rst | 17 +
.../doc/gfortran/compiler-characteristics.rst | 27 +
.../compiler-characteristics/asynchronous-i-o.rst | 29 +
.../data-consistency-and-durability.rst | 80 +
.../evaluation-of-logical-expressions.rst | 18 +
...file-format-of-unformatted-sequential-files.rst | 71 +
.../file-operations-on-symbolic-links.rst | 28 +
...pened-without-an-explicit-action=-specifier.rst | 23 +
...nternal-representation-of-logical-variables.rst | 24 +
.../kind-type-parameters.rst | 53 +
...-and-min-intrinsics-with-real-nan-arguments.rst | 21 +
.../thread-safety-of-the-runtime-library.rst | 53 +
gcc/fortran/doc/gfortran/conf.py | 32 +
gcc/fortran/doc/gfortran/contributing.rst | 29 +
.../doc/gfortran/contributors-to-gnu-fortran.rst | 111 +
gcc/fortran/doc/gfortran/copyright.rst | 1 +
.../extensions-implemented-in-gnu-fortran.rst | 1456 ++++++
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gcc/fortran/doc/gfortran/extensions.rst | 24 +
gcc/fortran/doc/gfortran/fortran-2003-status.rst | 206 +
gcc/fortran/doc/gfortran/fortran-2008-status.rst | 122 +
.../doc/gfortran/fortran-standards-status.rst | 16 +
.../doc/gfortran/function-abi-documentation.rst | 1526 +++++++
gcc/fortran/doc/gfortran/funding.rst | 6 +
.../doc/gfortran/general-public-license-3.rst | 6 +
.../doc/gfortran/gnu-fortran-command-options.rst | 38 +
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.../enable-and-customize-preprocessing.rst | 326 ++
.../environment-variables-affecting-gfortran.rst | 28 +
.../influencing-runtime-behavior.rst | 57 +
.../influencing-the-linking-step.rst | 26 +
.../gnu-fortran-command-options/option-summary.rst | 105 +
.../options-controlling-fortran-dialect.rst | 454 ++
.../options-for-code-generation-conventions.rst | 655 +++
...s-for-debugging-your-program-or-gnu-fortran.rst | 140 +
.../options-for-directory-search.rst | 82 +
...s-for-interoperability-with-other-languages.rst | 67 +
...-to-request-or-suppress-errors-and-warnings.rst | 518 +++
.../gfortran/gnu-fortran-compiler-directives.rst | 174 +
.../gfortran/gnu-free-documentation-license.rst | 6 +
gcc/fortran/doc/gfortran/index.rst | 43 +
.../doc/gfortran/interoperability-with-c.rst | 451 ++
gcc/fortran/doc/gfortran/intrinsic-modules.rst | 20 +
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.../openmp-modules-omplib-and-omplibkinds.rst | 161 +
gcc/fortran/doc/gfortran/intrinsic-procedures.rst | 300 ++
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.../ompunsetnestlock.rst | 35 +
libgomp/doc/reporting-bugs.rst | 18 +
libgomp/doc/the-libgomp-abi.rst | 31 +
.../implementing-atomic-construct.rst | 21 +
.../implementing-barrier-construct.rst | 13 +
.../implementing-critical-construct.rst | 30 +
...-lastprivate-copyin-and-copyprivate-clauses.rst | 45 +
.../implementing-flush-construct.rst | 11 +
.../the-libgomp-abi/implementing-for-construct.rst | 73 +
.../implementing-master-construct.rst | 18 +
.../implementing-openaccs-parallel-construct.rst | 17 +
.../implementing-ordered-construct.rst | 14 +
.../implementing-parallel-construct.rst | 55 +
.../implementing-private-clause.rst | 17 +
.../implementing-reduction-clause.rst | 15 +
.../implementing-sections-construct.rst | 42 +
.../implementing-single-construct.rst | 48 +
.../implementing-threadprivate-construct.rst | 18 +
libiberty/doc/bsd.rst | 6 +
libiberty/doc/conf.py | 24 +
libiberty/doc/copyright.rst | 1 +
libiberty/doc/extensions.rst | 756 ++++
.../doc/function-variable-and-macro-listing.rst | 1865 ++++++++
libiberty/doc/index.rst | 28 +
libiberty/doc/indices-and-tables.rst | 6 +
.../doc/lesser-general-public-license-2.1.rst | 6 +
libiberty/doc/overview.rst | 20 +
libiberty/doc/replacement-functions.rst | 66 +
libiberty/doc/supplemental-functions.rst | 35 +
libiberty/doc/using.rst | 44 +
libitm/doc/c-c++-language-constructs-for-tm.rst | 43 +
libitm/doc/conf.py | 23 +
libitm/doc/copyright.rst | 1 +
libitm/doc/enabling-libitm.rst | 17 +
libitm/doc/gnu-free-documentation-license.rst | 6 +
libitm/doc/index.rst | 28 +
libitm/doc/indices-and-tables.rst | 6 +
libitm/doc/internals.rst | 16 +
libitm/doc/locking-conventions.rst | 268 ++
libitm/doc/nesting-flat-vs-closed.rst | 28 +
libitm/doc/the-libitm-abi.rst | 27 +
libitm/doc/the-libitm-abi/function-list.rst | 271 ++
.../future-enhancements-to-the-abi.rst | 7 +
.../the-libitm-abi/library-design-principles.rst | 61 +
libitm/doc/the-libitm-abi/memory-model.rst | 22 +
libitm/doc/the-libitm-abi/non-objectives.rst | 7 +
libitm/doc/the-libitm-abi/objectives.rst | 7 +
libitm/doc/the-libitm-abi/sample-code.rst | 10 +
.../doc/the-libitm-abi/types-and-macros-list.rst | 11 +
libitm/doc/tm-methods-and-method-groups.rst | 47 +
libquadmath/doc/conf.py | 23 +
libquadmath/doc/copyright.rst | 1 +
libquadmath/doc/gnu-free-documentation-license.rst | 6 +
libquadmath/doc/i-o-library-routines.rst | 15 +
libquadmath/doc/index.rst | 27 +
libquadmath/doc/indices-and-tables.rst | 6 +
libquadmath/doc/math-library-routines.rst | 108 +
libquadmath/doc/quadmathsnprintf.rst | 79 +
libquadmath/doc/reporting-bugs.rst | 20 +
libquadmath/doc/strtoflt128.rst | 40 +
libquadmath/doc/typedef-and-constants.rst | 47 +
1302 files changed, 176026 insertions(+)
diff --git a/doc/Makefile b/doc/Makefile
new file mode 100644
index 00000000000..9e305a8e7da
--- /dev/null
+++ b/doc/Makefile
@@ -0,0 +1,97 @@
+# Makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line.
+SPHINXOPTS ?= -j auto -q
+SPHINXBUILD ?= sphinx-build
+PAPER ?=
+SOURCEDIR = .
+BUILDDIR = _build
+
+# Internal variables.
+PAPEROPT_a4 = -D latex_elements.papersize=a4paper
+PAPEROPT_letter = -D latex_elements.papersize=letterpaper
+# $(O) is meant as a shortcut for $(SPHINXOPTS)
+ALLSPHINXOPTS = -d $(BUILDDIR)/doctrees $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) $(O) $(SOURCEDIR)
+# the i18n builder cannot share the environment and doctrees with the others
+I18NSPHINXOPTS = $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) $(O) $(SOURCEDIR)
+
+.PHONY: help
+help:
+ @echo "Please use \`make <target>' where <target> is one of"
+ @echo " html to make standalone HTML files"
+ @echo " dirhtml to make HTML files named index.html in directories"
+ @echo " singlehtml to make a single large HTML file"
+ @echo " pickle to make pickle files"
+ @echo " json to make JSON files"
+ @echo " htmlhelp to make HTML files and an HTML help project"
+ @echo " qthelp to make HTML files and a qthelp project"
+ @echo " applehelp to make an Apple Help Book"
+ @echo " devhelp to make HTML files and a Devhelp project"
+ @echo " epub to make an epub"
+ @echo " latex to make LaTeX files (you can set PAPER=a4 or PAPER=letter)"
+ @echo " latexpdf to make LaTeX files and then PDFs out of them"
+ @echo " latexpdfja to make LaTeX files and run them through platex/dvipdfmx"
+ @echo " lualatexpdf to make LaTeX files and run them through lualatex"
+ @echo " xelatexpdf to make LaTeX files and run them through xelatex"
+ @echo " text to make text files"
+ @echo " man to make manual pages"
+ @echo " texinfo to make Texinfo files"
+ @echo " info to make Texinfo files and run them through makeinfo"
+ @echo " gettext to make PO message catalogs"
+ @echo " changes to make an overview of all changed/added/deprecated items"
+ @echo " xml to make Docutils-native XML files"
+ @echo " pseudoxml to make pseudoxml-XML files for display purposes"
+ @echo " linkcheck to check all external links for integrity"
+ @echo " doctest to run all doctests embedded in the documentation (if enabled)"
+ @echo " coverage to run coverage check of the documentation (if enabled)"
+ @echo " dummy to check syntax errors of document sources"
+
+.PHONY: clean
+clean:
+ rm -rf $(BUILDDIR)
+
+.PHONY: latexpdf
+latexpdf:
+ $(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+ @echo "Running LaTeX files through pdflatex..."
+ $(MAKE) LATEXMKOPTS="-interaction=nonstopmode -f" -C $(BUILDDIR)/latex all-pdf
+ @echo "pdflatex finished; the PDF files are in $(BUILDDIR)/latex."
+
+.PHONY: latexpdfja
+latexpdfja:
+ $(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+ @echo "Running LaTeX files through platex and dvipdfmx..."
+ $(MAKE) -C $(BUILDDIR)/latex all-pdf-ja
+ @echo "pdflatex finished; the PDF files are in $(BUILDDIR)/latex."
+
+.PHONY: lualatexpdf
+lualatexpdf:
+ $(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+ @echo "Running LaTeX files through lualatex..."
+ $(MAKE) PDFLATEX=lualatex -C $(BUILDDIR)/latex all-pdf
+ @echo "lualatex finished; the PDF files are in $(BUILDDIR)/latex."
+
+.PHONY: xelatexpdf
+xelatexpdf:
+ $(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+ @echo "Running LaTeX files through xelatex..."
+ $(MAKE) PDFLATEX=xelatex -C $(BUILDDIR)/latex all-pdf
+ @echo "xelatex finished; the PDF files are in $(BUILDDIR)/latex."
+
+.PHONY: info
+info:
+ $(SPHINXBUILD) -b texinfo $(ALLSPHINXOPTS) $(BUILDDIR)/texinfo
+ @echo "Running Texinfo files through makeinfo..."
+ make -C $(BUILDDIR)/texinfo info
+ @echo "makeinfo finished; the Info files are in $(BUILDDIR)/texinfo."
+
+.PHONY: gettext
+gettext:
+ $(SPHINXBUILD) -b gettext $(I18NSPHINXOPTS) $(BUILDDIR)/locale
+
+# Catch-all target: route all unknown targets to Sphinx
+.PHONY: Makefile
+%: Makefile
+ $(SPHINXBUILD) -b "$@" $(ALLSPHINXOPTS) "$(BUILDDIR)/$@"
+
diff --git a/doc/baseconf.py b/doc/baseconf.py
new file mode 100644
index 00000000000..1ed19cc0579
--- /dev/null
+++ b/doc/baseconf.py
@@ -0,0 +1,103 @@
+# Configuration file for the Sphinx documentation builder.
+#
+# This file only contains a selection of the most common options. For a full
+# list see the documentation:
+# https://www.sphinx-doc.org/en/master/usage/configuration.html
+
+# -- Path setup --------------------------------------------------------------
+
+# If extensions (or modules to document with autodoc) are in another directory,
+# add these directories to sys.path here. If the directory is relative to the
+# documentation root, use os.path.abspath to make it absolute, like shown here.
+#
+import os
+# import sys
+# sys.path.insert(0, os.path.abspath('.'))
+
+
+# -- Project information -----------------------------------------------------
+
+# The full version, including alpha/beta/rc tags
+
+# FIXME
+folder = os.path.dirname(os.path.realpath(__file__))
+gcc_srcdir = os.path.join(folder, './objdir')
+
+def __read_file(name):
+ path = os.path.join(gcc_srcdir, name)
+ if os.path.exists(path):
+ return open(path).read().strip()
+ else:
+ return ''
+
+gcc_BASEVER = __read_file('BASE-VER')
+gcc_DEVPHASE = __read_file('DEV-PHASE')
+gcc_DATESTAMP = __read_file('DATESTAMP')
+gcc_REVISION = __read_file('REVISION')
+
+VERSION_PACKAGE = os.getenv('VERSION_PACKAGE', '(GCC)')
+BUGURL = os.getenv('BUGURL', 'https://gcc.gnu.org/bugs/')
+
+# The short X.Y version.
+version = gcc_BASEVER
+
+# The full version, including alpha/beta/rc tags.
+release = ('%s (%s %s%s)'
+ % (gcc_BASEVER, gcc_DEVPHASE, gcc_DATESTAMP,
+ (' %s' % gcc_REVISION) if gcc_REVISION else ''))
+
+rst_epilog = '''
+.. |gcc_version| replace:: %s
+.. |package_version| replace:: %s
+.. |bugurl| replace:: %s
+''' % (gcc_BASEVER, VERSION_PACKAGE, BUGURL)
+
+# -- General configuration ---------------------------------------------------
+
+# Add any Sphinx extension module names here, as strings. They can be
+# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
+# ones.
+extensions = [
+]
+
+# Add any paths that contain templates here, relative to this directory.
+templates_path = ['_templates']
+
+# List of patterns, relative to source directory, that match files and
+# directories to ignore when looking for source files.
+# This pattern also affects html_static_path and html_extra_path.
+exclude_patterns = ['_build']
+
+# For legacy Sphinx versions (< 2.0)
+master_doc = 'index'
+
+# -- Options for HTML output -------------------------------------------------
+
+# The theme to use for HTML and HTML Help pages. See the documentation for
+# a list of builtin themes.
+#
+html_theme = 'sphinx_rtd_theme'
+
+# Theme options are theme-specific and customize the look and feel of a theme
+# further. For a list of options available for each theme, see the
+# documentation.
+html_theme_options = {
+ 'prev_next_buttons_location': 'both',
+ 'navigation_with_keys': True
+}
+
+# By default, do not generate any manual pages
+man_pages = []
+
+# FIXME: handle WARNINGs: unknown option issues and cross refs
+suppress_warnings = [
+ 'ref.option',
+ 'ref.ref'
+]
+
+# RTD template requires at least Sphinx 1.6
+# sphinx-build -j auto is supported since 1.7
+needs_sphinx = '1.7'
+
+# Use xelatex by default
+latex_engine = 'xelatex'
diff --git a/doc/bsd.rst b/doc/bsd.rst
new file mode 100644
index 00000000000..5624c3701b4
--- /dev/null
+++ b/doc/bsd.rst
@@ -0,0 +1,39 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+BSD
+===
+
+Copyright (C) 1990 Regents of the University of California.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+#. Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+
+#. Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+
+#. [rescinded 22 July 1999]
+
+#. Neither the name of the University nor the names of its contributors
+ may be used to endorse or promote products derived from this software
+ without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS 'AS IS' AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGE.
\ No newline at end of file
diff --git a/doc/contrib.rst b/doc/contrib.rst
new file mode 100644
index 00000000000..7e877dc94f8
--- /dev/null
+++ b/doc/contrib.rst
@@ -0,0 +1,1277 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _contributors:
+
+Contributors to GCC
+===================
+
+.. index:: contributors
+
+The GCC project would like to thank its many contributors. Without them the
+project would not have been nearly as successful as it has been. Any omissions
+in this list are accidental. Feel free to contact
+law@redhat.com or gerald@pfeifer.com if you have been left
+out or some of your contributions are not listed. Please keep this list in
+alphabetical order.
+
+* Analog Devices helped implement the support for complex data types
+ and iterators.
+
+* John David Anglin for threading-related fixes and improvements to
+ libstdc++-v3, and the HP-UX port.
+
+* James van Artsdalen wrote the code that makes efficient use of
+ the Intel 80387 register stack.
+
+* Abramo and Roberto Bagnara for the SysV68 Motorola 3300 Delta Series
+ port.
+
+* Alasdair Baird for various bug fixes.
+
+* Giovanni Bajo for analyzing lots of complicated C++ problem reports.
+
+* Peter Barada for his work to improve code generation for new
+ ColdFire cores.
+
+* Gerald Baumgartner added the signature extension to the C++ front end.
+
+* Godmar Back for his Java improvements and encouragement.
+
+* Scott Bambrough for help porting the Java compiler.
+
+* Wolfgang Bangerth for processing tons of bug reports.
+
+* Jon Beniston for his Microsoft Windows port of Java and port to Lattice Mico32.
+
+* Daniel Berlin for better DWARF 2 support, faster/better optimizations,
+ improved alias analysis, plus migrating GCC to Bugzilla.
+
+* Geoff Berry for his Java object serialization work and various patches.
+
+* David Binderman tests weekly snapshots of GCC trunk against Fedora Rawhide
+ for several architectures.
+
+* Laurynas Biveinis for memory management work and DJGPP port fixes.
+
+* Uros Bizjak for the implementation of x87 math built-in functions and
+ for various middle end and i386 back end improvements and bug fixes.
+
+* Eric Blake for helping to make GCJ and libgcj conform to the
+ specifications.
+
+* Janne Blomqvist for contributions to GNU Fortran.
+
+* Hans-J. Boehm for his garbage collector, IA-64 libffi port, and other
+ Java work.
+
+* Segher Boessenkool for helping maintain the PowerPC port and the
+ instruction combiner plus various contributions to the middle end.
+
+* Neil Booth for work on cpplib, lang hooks, debug hooks and other
+ miscellaneous clean-ups.
+
+* Steven Bosscher for integrating the GNU Fortran front end into GCC and for
+ contributing to the tree-ssa branch.
+
+* Eric Botcazou for fixing middle- and backend bugs left and right.
+
+* Per Bothner for his direction via the steering committee and various
+ improvements to the infrastructure for supporting new languages. Chill
+ front end implementation. Initial implementations of
+ cpplib, fix-header, config.guess, libio, and past C++ library (libg++)
+ maintainer. Dreaming up, designing and implementing much of GCJ.
+
+* Devon Bowen helped port GCC to the Tahoe.
+
+* Don Bowman for mips-vxworks contributions.
+
+* James Bowman for the FT32 port.
+
+* Dave Brolley for work on cpplib and Chill.
+
+* Paul Brook for work on the ARM architecture and maintaining GNU Fortran.
+
+* Robert Brown implemented the support for Encore 32000 systems.
+
+* Christian Bruel for improvements to local store elimination.
+
+* Herman A.J. ten Brugge for various fixes.
+
+* Joerg Brunsmann for Java compiler hacking and help with the GCJ FAQ.
+
+* Joe Buck for his direction via the steering committee from its creation
+ to 2013.
+
+* Iain Buclaw for the D frontend.
+
+* Craig Burley for leadership of the G77 Fortran effort.
+
+* Tobias Burnus for contributions to GNU Fortran.
+
+* Stephan Buys for contributing Doxygen notes for libstdc++.
+
+* Paolo Carlini for libstdc++ work: lots of efficiency improvements to
+ the C++ strings, streambufs and formatted I/O, hard detective work on
+ the frustrating localization issues, and keeping up with the problem reports.
+
+* John Carr for his alias work, SPARC hacking, infrastructure improvements,
+ previous contributions to the steering committee, loop optimizations, etc.
+
+* Stephane Carrez for 68HC11 and 68HC12 ports.
+
+* Steve Chamberlain for support for the Renesas SH and H8 processors
+ and the PicoJava processor, and for GCJ config fixes.
+
+* Glenn Chambers for help with the GCJ FAQ.
+
+* John-Marc Chandonia for various libgcj patches.
+
+* Denis Chertykov for contributing and maintaining the AVR port, the first GCC port
+ for an 8-bit architecture.
+
+* Kito Cheng for his work on the RISC-V port, including bringing up the test
+ suite and maintenance.
+
+* Scott Christley for his Objective-C contributions.
+
+* Eric Christopher for his Java porting help and clean-ups.
+
+* Branko Cibej for more warning contributions.
+
+* The `GNU Classpath project <http://www.gnu.org/software/classpath/>`_
+ for all of their merged runtime code.
+
+* Nick Clifton for arm, mcore, fr30, v850, m32r, msp430 rx work,
+ :option:`--help`, and other random hacking.
+
+* Michael Cook for libstdc++ cleanup patches to reduce warnings.
+
+* R. Kelley Cook for making GCC buildable from a read-only directory as
+ well as other miscellaneous build process and documentation clean-ups.
+
+* Ralf Corsepius for SH testing and minor bug fixing.
+
+* François-Xavier Coudert for contributions to GNU Fortran.
+
+* Stan Cox for care and feeding of the x86 port and lots of behind
+ the scenes hacking.
+
+* Alex Crain provided changes for the 3b1.
+
+* Ian Dall for major improvements to the NS32k port.
+
+* Paul Dale for his work to add uClinux platform support to the
+ m68k backend.
+
+* Palmer Dabbelt for his work maintaining the RISC-V port.
+
+* Dario Dariol contributed the four varieties of sample programs
+ that print a copy of their source.
+
+* Russell Davidson for fstream and stringstream fixes in libstdc++.
+
+* Bud Davis for work on the G77 and GNU Fortran compilers.
+
+* Mo DeJong for GCJ and libgcj bug fixes.
+
+* Jerry DeLisle for contributions to GNU Fortran.
+
+* DJ Delorie for the DJGPP port, build and libiberty maintenance,
+ various bug fixes, and the M32C, MeP, MSP430, and RL78 ports.
+
+* Arnaud Desitter for helping to debug GNU Fortran.
+
+* Gabriel Dos Reis for contributions to G++, contributions and
+ maintenance of GCC diagnostics infrastructure, libstdc++-v3,
+ including ``valarray<>``, ``complex<>``, maintaining the numerics library
+ (including that pesky ``<limits>`` :-) and keeping up-to-date anything
+ to do with numbers.
+
+* Ulrich Drepper for his work on glibc, testing of GCC using glibc, ISO C99
+ support, CFG dumping support, etc., plus support of the C++ runtime
+ libraries including for all kinds of C interface issues, contributing and
+ maintaining ``complex<>``, sanity checking and disbursement, configuration
+ architecture, libio maintenance, and early math work.
+
+* François Dumont for his work on libstdc++-v3, especially maintaining and
+ improving ``debug-mode`` and associative and unordered containers.
+
+* Zdenek Dvorak for a new loop unroller and various fixes.
+
+* Michael Eager for his work on the Xilinx MicroBlaze port.
+
+* Richard Earnshaw for his ongoing work with the ARM.
+
+* David Edelsohn for his direction via the steering committee, ongoing work
+ with the RS6000/PowerPC port, help cleaning up Haifa loop changes,
+ doing the entire AIX port of libstdc++ with his bare hands, and for
+ ensuring GCC properly keeps working on AIX.
+
+* Kevin Ediger for the floating point formatting of num_put::do_put in
+ libstdc++.
+
+* Phil Edwards for libstdc++ work including configuration hackery,
+ documentation maintainer, chief breaker of the web pages, the occasional
+ iostream bug fix, and work on shared library symbol versioning.
+
+* Paul Eggert for random hacking all over GCC.
+
+* Mark Elbrecht for various DJGPP improvements, and for libstdc++
+ configuration support for locales and fstream-related fixes.
+
+* Vadim Egorov for libstdc++ fixes in strings, streambufs, and iostreams.
+
+* Christian Ehrhardt for dealing with bug reports.
+
+* Ben Elliston for his work to move the Objective-C runtime into its
+ own subdirectory and for his work on autoconf.
+
+* Revital Eres for work on the PowerPC 750CL port.
+
+* Marc Espie for OpenBSD support.
+
+* Doug Evans for much of the global optimization framework, arc, m32r,
+ and SPARC work.
+
+* Christopher Faylor for his work on the Cygwin port and for caring and
+ feeding the gcc.gnu.org box and saving its users tons of spam.
+
+* Fred Fish for BeOS support and Ada fixes.
+
+* Ivan Fontes Garcia for the Portuguese translation of the GCJ FAQ.
+
+* Peter Gerwinski for various bug fixes and the Pascal front end.
+
+* Kaveh R. Ghazi for his direction via the steering committee, amazing
+ work to make :samp:`-W -Wall -W* -Werror` useful, and
+ testing GCC on a plethora of platforms. Kaveh extends his gratitude to
+ the CAIP Center at Rutgers University for providing him with computing
+ resources to work on Free Software from the late 1980s to 2010.
+
+* John Gilmore for a donation to the FSF earmarked improving GNU Java.
+
+* Judy Goldberg for c++ contributions.
+
+* Torbjorn Granlund for various fixes and the c-torture testsuite,
+ multiply- and divide-by-constant optimization, improved long long
+ support, improved leaf function register allocation, and his direction
+ via the steering committee.
+
+* Jonny Grant for improvements to ``collect2's`` :option:`--help` documentation.
+
+* Anthony Green for his :option:`-Os` contributions, the moxie port, and
+ Java front end work.
+
+* Stu Grossman for gdb hacking, allowing GCJ developers to debug Java code.
+
+* Michael K. Gschwind contributed the port to the PDP-11.
+
+* Richard Biener for his ongoing middle-end contributions and bug fixes
+ and for release management.
+
+* Ron Guilmette implemented the :command:`protoize` and :command:`unprotoize`
+ tools, the support for DWARF 1 symbolic debugging information, and much of
+ the support for System V Release 4. He has also worked heavily on the
+ Intel 386 and 860 support.
+
+* Sumanth Gundapaneni for contributing the CR16 port.
+
+* Mostafa Hagog for Swing Modulo Scheduling (SMS) and post reload GCSE.
+
+* Bruno Haible for improvements in the runtime overhead for EH, new
+ warnings and assorted bug fixes.
+
+* Andrew Haley for his amazing Java compiler and library efforts.
+
+* Chris Hanson assisted in making GCC work on HP-UX for the 9000 series 300.
+
+* Michael Hayes for various thankless work he's done trying to get
+ the c30/c40 ports functional. Lots of loop and unroll improvements and
+ fixes.
+
+* Dara Hazeghi for wading through myriads of target-specific bug reports.
+
+* Kate Hedstrom for staking the G77 folks with an initial testsuite.
+
+* Richard Henderson for his ongoing SPARC, alpha, ia32, and ia64 work, loop
+ opts, and generally fixing lots of old problems we've ignored for
+ years, flow rewrite and lots of further stuff, including reviewing
+ tons of patches.
+
+* Aldy Hernandez for working on the PowerPC port, SIMD support, and
+ various fixes.
+
+* Nobuyuki Hikichi of Software Research Associates, Tokyo, contributed
+ the support for the Sony NEWS machine.
+
+* Kazu Hirata for caring and feeding the Renesas H8/300 port and various fixes.
+
+* Katherine Holcomb for work on GNU Fortran.
+
+* Manfred Hollstein for his ongoing work to keep the m88k alive, lots
+ of testing and bug fixing, particularly of GCC configury code.
+
+* Steve Holmgren for MachTen patches.
+
+* Mat Hostetter for work on the TILE-Gx and TILEPro ports.
+
+* Jan Hubicka for his x86 port improvements.
+
+* Falk Hueffner for working on C and optimization bug reports.
+
+* Bernardo Innocenti for his m68k work, including merging of
+ ColdFire improvements and uClinux support.
+
+* Christian Iseli for various bug fixes.
+
+* Kamil Iskra for general m68k hacking.
+
+* Lee Iverson for random fixes and MIPS testing.
+
+* Balaji V. Iyer for Cilk+ development and merging.
+
+* Andreas Jaeger for testing and benchmarking of GCC and various bug fixes.
+
+* Martin Jambor for his work on inter-procedural optimizations, the
+ switch conversion pass, and scalar replacement of aggregates.
+
+* Jakub Jelinek for his SPARC work and sibling call optimizations as well
+ as lots of bug fixes and test cases, and for improving the Java build
+ system.
+
+* Janis Johnson for ia64 testing and fixes, her quality improvement
+ sidetracks, and web page maintenance.
+
+* Kean Johnston for SCO OpenServer support and various fixes.
+
+* Tim Josling for the sample language treelang based originally on Richard
+ Kenner's 'toy' language.
+
+* Nicolai Josuttis for additional libstdc++ documentation.
+
+* Klaus Kaempf for his ongoing work to make alpha-vms a viable target.
+
+* Steven G. Kargl for work on GNU Fortran.
+
+* David Kashtan of SRI adapted GCC to VMS.
+
+* Ryszard Kabatek for many, many libstdc++ bug fixes and optimizations of
+ strings, especially member functions, and for auto_ptr fixes.
+
+* Geoffrey Keating for his ongoing work to make the PPC work for GNU/Linux
+ and his automatic regression tester.
+
+* Brendan Kehoe for his ongoing work with G++ and for a lot of early work
+ in just about every part of libstdc++.
+
+* Oliver M. Kellogg of Deutsche Aerospace contributed the port to the
+ MIL-STD-1750A.
+
+* Richard Kenner of the New York University Ultracomputer Research
+ Laboratory wrote the machine descriptions for the AMD 29000, the DEC
+ Alpha, the IBM RT PC, and the IBM RS/6000 as well as the support for
+ instruction attributes. He also made changes to better support RISC
+ processors including changes to common subexpression elimination,
+ strength reduction, function calling sequence handling, and condition
+ code support, in addition to generalizing the code for frame pointer
+ elimination and delay slot scheduling. Richard Kenner was also the
+ head maintainer of GCC for several years.
+
+* Mumit Khan for various contributions to the Cygwin and Mingw32 ports and
+ maintaining binary releases for Microsoft Windows hosts, and for massive libstdc++
+ porting work to Cygwin/Mingw32.
+
+* Robin Kirkham for cpu32 support.
+
+* Mark Klein for PA improvements.
+
+* Thomas Koenig for various bug fixes.
+
+* Bruce Korb for the new and improved fixincludes code.
+
+* Benjamin Kosnik for his G++ work and for leading the libstdc++-v3 effort.
+
+* Maxim Kuvyrkov for contributions to the instruction scheduler, the Android
+ and m68k/Coldfire ports, and optimizations.
+
+* Charles LaBrec contributed the support for the Integrated Solutions
+ 68020 system.
+
+* Asher Langton and Mike Kumbera for contributing Cray pointer support
+ to GNU Fortran, and for other GNU Fortran improvements.
+
+* Jeff Law for his direction via the steering committee, coordinating the
+ entire egcs project and GCC 2.95, rolling out snapshots and releases,
+ handling merges from GCC2, reviewing tons of patches that might have
+ fallen through the cracks else, and random but extensive hacking.
+
+* Walter Lee for work on the TILE-Gx and TILEPro ports.
+
+* Marc Lehmann for his direction via the steering committee and helping
+ with analysis and improvements of x86 performance.
+
+* Victor Leikehman for work on GNU Fortran.
+
+* Ted Lemon wrote parts of the RTL reader and printer.
+
+* Kriang Lerdsuwanakij for C++ improvements including template as template
+ parameter support, and many C++ fixes.
+
+* Warren Levy for tremendous work on libgcj (Java Runtime Library) and
+ random work on the Java front end.
+
+* Alain Lichnewsky ported GCC to the MIPS CPU.
+
+* Oskar Liljeblad for hacking on AWT and his many Java bug reports and
+ patches.
+
+* Robert Lipe for OpenServer support, new testsuites, testing, etc.
+
+* Chen Liqin for various S+core related fixes/improvement, and for
+ maintaining the S+core port.
+
+* Martin Liska for his work on identical code folding, the sanitizers,
+ HSA, general bug fixing and for running automated regression testing of GCC
+ and reporting numerous bugs.
+
+* Weiwen Liu for testing and various bug fixes.
+
+* Manuel López-Ibáñez for improving :option:`-Wconversion` and
+ many other diagnostics fixes and improvements.
+
+* Dave Love for his ongoing work with the Fortran front end and
+ runtime libraries.
+
+* Martin von Löwis for internal consistency checking infrastructure,
+ various C++ improvements including namespace support, and tons of
+ assistance with libstdc++/compiler merges.
+
+* H.J. Lu for his previous contributions to the steering committee, many x86
+ bug reports, prototype patches, and keeping the GNU/Linux ports working.
+
+* Greg McGary for random fixes and (someday) bounded pointers.
+
+* Andrew MacLeod for his ongoing work in building a real EH system,
+ various code generation improvements, work on the global optimizer, etc.
+
+* Vladimir Makarov for hacking some ugly i960 problems, PowerPC hacking
+ improvements to compile-time performance, overall knowledge and
+ direction in the area of instruction scheduling, design and
+ implementation of the automaton based instruction scheduler and
+ design and implementation of the integrated and local register allocators.
+
+* David Malcolm for his work on improving GCC diagnostics, JIT, self-tests
+ and unit testing.
+
+* Bob Manson for his behind the scenes work on dejagnu.
+
+* John Marino for contributing the DragonFly BSD port.
+
+* Philip Martin for lots of libstdc++ string and vector iterator fixes and
+ improvements, and string clean up and testsuites.
+
+* Michael Matz for his work on dominance tree discovery, the x86-64 port,
+ link-time optimization framework and general optimization improvements.
+
+* All of the Mauve project contributors for Java test code.
+
+* Bryce McKinlay for numerous GCJ and libgcj fixes and improvements.
+
+* Adam Megacz for his work on the Microsoft Windows port of GCJ.
+
+* Michael Meissner for LRS framework, ia32, m32r, v850, m88k, MIPS,
+ powerpc, haifa, ECOFF debug support, and other assorted hacking.
+
+* Jason Merrill for his direction via the steering committee and leading
+ the G++ effort.
+
+* Martin Michlmayr for testing GCC on several architectures using the
+ entire Debian archive.
+
+* David Miller for his direction via the steering committee, lots of
+ SPARC work, improvements in jump.c and interfacing with the Linux kernel
+ developers.
+
+* Gary Miller ported GCC to Charles River Data Systems machines.
+
+* Alfred Minarik for libstdc++ string and ios bug fixes, and turning the
+ entire libstdc++ testsuite namespace-compatible.
+
+* Mark Mitchell for his direction via the steering committee, mountains of
+ C++ work, load/store hoisting out of loops, alias analysis improvements,
+ ISO C ``restrict`` support, and serving as release manager from 2000
+ to 2011.
+
+* Alan Modra for various GNU/Linux bits and testing.
+
+* Toon Moene for his direction via the steering committee, Fortran
+ maintenance, and his ongoing work to make us make Fortran run fast.
+
+* Jason Molenda for major help in the care and feeding of all the services
+ on the gcc.gnu.org (formerly egcs.cygnus.com) machine---mail, web
+ services, ftp services, etc etc. Doing all this work on scrap paper and
+ the backs of envelopes would have been... difficult.
+
+* Catherine Moore for fixing various ugly problems we have sent her
+ way, including the haifa bug which was killing the Alpha & PowerPC
+ Linux kernels.
+
+* Mike Moreton for his various Java patches.
+
+* David Mosberger-Tang for various Alpha improvements, and for the initial
+ IA-64 port.
+
+* Stephen Moshier contributed the floating point emulator that assists in
+ cross-compilation and permits support for floating point numbers wider
+ than 64 bits and for ISO C99 support.
+
+* Bill Moyer for his behind the scenes work on various issues.
+
+* Philippe De Muyter for his work on the m68k port.
+
+* Joseph S. Myers for his work on the PDP-11 port, format checking and ISO
+ C99 support, and continuous emphasis on (and contributions to) documentation.
+
+* Nathan Myers for his work on libstdc++-v3: architecture and authorship
+ through the first three snapshots, including implementation of locale
+ infrastructure, string, shadow C headers, and the initial project
+ documentation (DESIGN, CHECKLIST, and so forth). Later, more work on
+ MT-safe string and shadow headers.
+
+* Felix Natter for documentation on porting libstdc++.
+
+* Nathanael Nerode for cleaning up the configuration/build process.
+
+* NeXT, Inc. donated the front end that supports the Objective-C
+ language.
+
+* Hans-Peter Nilsson for the CRIS and MMIX ports, improvements to the search
+ engine setup, various documentation fixes and other small fixes.
+
+* Geoff Noer for his work on getting cygwin native builds working.
+
+* Vegard Nossum for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Diego Novillo for his work on Tree SSA, OpenMP, SPEC performance
+ tracking web pages, GIMPLE tuples, and assorted fixes.
+
+* David O'Brien for the FreeBSD/alpha, FreeBSD/AMD x86-64, FreeBSD/ARM,
+ FreeBSD/PowerPC, and FreeBSD/SPARC64 ports and related infrastructure
+ improvements.
+
+* Alexandre Oliva for various build infrastructure improvements, scripts and
+ amazing testing work, including keeping libtool issues sane and happy.
+
+* Stefan Olsson for work on mt_alloc.
+
+* Melissa O'Neill for various NeXT fixes.
+
+* Rainer Orth for random MIPS work, including improvements to GCC's o32
+ ABI support, improvements to dejagnu's MIPS support, Java configuration
+ clean-ups and porting work, and maintaining the IRIX, Solaris 2, and
+ Tru64 UNIX ports.
+
+* Steven Pemberton for his contribution of :samp:`enquire` which allowed GCC to
+ determine various properties of the floating point unit and generate
+ :samp:`float.h` in older versions of GCC.
+
+* Hartmut Penner for work on the s390 port.
+
+* Paul Petersen wrote the machine description for the Alliant FX/8.
+
+* Alexandre Petit-Bianco for implementing much of the Java compiler and
+ continued Java maintainership.
+
+* Matthias Pfaller for major improvements to the NS32k port.
+
+* Gerald Pfeifer for his direction via the steering committee, pointing
+ out lots of problems we need to solve, maintenance of the web pages, and
+ taking care of documentation maintenance in general.
+
+* Marek Polacek for his work on the C front end, the sanitizers and general
+ bug fixing.
+
+* Andrew Pinski for processing bug reports by the dozen.
+
+* Ovidiu Predescu for his work on the Objective-C front end and runtime
+ libraries.
+
+* Jerry Quinn for major performance improvements in C++ formatted I/O.
+
+* Ken Raeburn for various improvements to checker, MIPS ports and various
+ cleanups in the compiler.
+
+* Rolf W. Rasmussen for hacking on AWT.
+
+* David Reese of Sun Microsystems contributed to the Solaris on PowerPC
+ port.
+
+* John Regehr for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Volker Reichelt for running automated regression testing of GCC and reporting
+ numerous bugs and for keeping up with the problem reports.
+
+* Joern Rennecke for maintaining the sh port, loop, regmove & reload
+ hacking and developing and maintaining the Epiphany port.
+
+* Loren J. Rittle for improvements to libstdc++-v3 including the FreeBSD
+ port, threading fixes, thread-related configury changes, critical
+ threading documentation, and solutions to really tricky I/O problems,
+ as well as keeping GCC properly working on FreeBSD and continuous testing.
+
+* Craig Rodrigues for processing tons of bug reports.
+
+* Ola Rönnerup for work on mt_alloc.
+
+* Gavin Romig-Koch for lots of behind the scenes MIPS work.
+
+* David Ronis inspired and encouraged Craig to rewrite the G77
+ documentation in texinfo format by contributing a first pass at a
+ translation of the old :samp:`g77-0.5.16/f/DOC` file.
+
+* Ken Rose for fixes to GCC's delay slot filling code.
+
+* Ira Rosen for her contributions to the auto-vectorizer.
+
+* Paul Rubin wrote most of the preprocessor.
+
+* Pétur Runólfsson for major performance improvements in C++ formatted I/O and
+ large file support in C++ filebuf.
+
+* Chip Salzenberg for libstdc++ patches and improvements to locales, traits,
+ Makefiles, libio, libtool hackery, and 'long long' support.
+
+* Juha Sarlin for improvements to the H8 code generator.
+
+* Greg Satz assisted in making GCC work on HP-UX for the 9000 series 300.
+
+* Roger Sayle for improvements to constant folding and GCC's RTL optimizers
+ as well as for fixing numerous bugs.
+
+* Bradley Schatz for his work on the GCJ FAQ.
+
+* Peter Schauer wrote the code to allow debugging to work on the Alpha.
+
+* William Schelter did most of the work on the Intel 80386 support.
+
+* Tobias Schlüter for work on GNU Fortran.
+
+* Bernd Schmidt for various code generation improvements and major
+ work in the reload pass, serving as release manager for
+ GCC 2.95.3, and work on the Blackfin and C6X ports.
+
+* Peter Schmid for constant testing of libstdc++---especially application
+ testing, going above and beyond what was requested for the release
+ criteria---and libstdc++ header file tweaks.
+
+* Jason Schroeder for jcf-dump patches.
+
+* Andreas Schwab for his work on the m68k port.
+
+* Lars Segerlund for work on GNU Fortran.
+
+* Dodji Seketeli for numerous C++ bug fixes and debug info improvements.
+
+* Tim Shen for major work on ``<regex>``.
+
+* Joel Sherrill for his direction via the steering committee, RTEMS
+ contributions and RTEMS testing.
+
+* Nathan Sidwell for many C++ fixes/improvements.
+
+* Jeffrey Siegal for helping RMS with the original design of GCC, some
+ code which handles the parse tree and RTL data structures, constant
+ folding and help with the original VAX & m68k ports.
+
+* Kenny Simpson for prompting libstdc++ fixes due to defect reports from
+ the LWG (thereby keeping GCC in line with updates from the ISO).
+
+* Franz Sirl for his ongoing work with making the PPC port stable
+ for GNU/Linux.
+
+* Andrey Slepuhin for assorted AIX hacking.
+
+* Trevor Smigiel for contributing the SPU port.
+
+* Christopher Smith did the port for Convex machines.
+
+* Danny Smith for his major efforts on the Mingw (and Cygwin) ports.
+ Retired from GCC maintainership August 2010, having mentored two
+ new maintainers into the role.
+
+* Randy Smith finished the Sun FPA support.
+
+* Ed Smith-Rowland for his continuous work on libstdc++-v3, special functions,
+ ``<random>``, and various improvements to C++11 features.
+
+* Scott Snyder for queue, iterator, istream, and string fixes and libstdc++
+ testsuite entries. Also for providing the patch to G77 to add
+ rudimentary support for ``INTEGER*1``, ``INTEGER*2``, and
+ ``LOGICAL*1``.
+
+* Zdenek Sojka for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Arseny Solokha for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Jayant Sonar for contributing the CR16 port.
+
+* Brad Spencer for contributions to the GLIBCPP_FORCE_NEW technique.
+
+* Richard Stallman, for writing the original GCC and launching the GNU project.
+
+* Jan Stein of the Chalmers Computer Society provided support for
+ Genix, as well as part of the 32000 machine description.
+
+* Gerhard Steinmetz for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Nigel Stephens for various mips16 related fixes/improvements.
+
+* Jonathan Stone wrote the machine description for the Pyramid computer.
+
+* Graham Stott for various infrastructure improvements.
+
+* John Stracke for his Java HTTP protocol fixes.
+
+* Mike Stump for his Elxsi port, G++ contributions over the years and more
+ recently his vxworks contributions
+
+* Jeff Sturm for Java porting help, bug fixes, and encouragement.
+
+* Zhendong Su for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Chengnian Sun for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Shigeya Suzuki for this fixes for the bsdi platforms.
+
+* Ian Lance Taylor for the Go frontend, the initial mips16 and mips64
+ support, general configury hacking, fixincludes, etc.
+
+* Holger Teutsch provided the support for the Clipper CPU.
+
+* Gary Thomas for his ongoing work to make the PPC work for GNU/Linux.
+
+* Paul Thomas for contributions to GNU Fortran.
+
+* Philipp Thomas for random bug fixes throughout the compiler
+
+* Jason Thorpe for thread support in libstdc++ on NetBSD.
+
+* Kresten Krab Thorup wrote the run time support for the Objective-C
+ language and the fantastic Java bytecode interpreter.
+
+* Michael Tiemann for random bug fixes, the first instruction scheduler,
+ initial C++ support, function integration, NS32k, SPARC and M88k
+ machine description work, delay slot scheduling.
+
+* Andreas Tobler for his work porting libgcj to Darwin.
+
+* Teemu Torma for thread safe exception handling support.
+
+* Leonard Tower wrote parts of the parser, RTL generator, and RTL
+ definitions, and of the VAX machine description.
+
+* Daniel Towner and Hariharan Sandanagobalane contributed and
+ maintain the picoChip port.
+
+* Tom Tromey for internationalization support and for his many Java
+ contributions and libgcj maintainership.
+
+* Lassi Tuura for improvements to config.guess to determine HP processor
+ types.
+
+* Petter Urkedal for libstdc++ CXXFLAGS, math, and algorithms fixes.
+
+* Andy Vaught for the design and initial implementation of the GNU Fortran
+ front end.
+
+* Brent Verner for work with the libstdc++ cshadow files and their
+ associated configure steps.
+
+* Todd Vierling for contributions for NetBSD ports.
+
+* Andrew Waterman for contributing the RISC-V port, as well as maintaining it.
+
+* Jonathan Wakely for contributing libstdc++ Doxygen notes and XHTML
+ guidance and maintaining libstdc++.
+
+* Dean Wakerley for converting the install documentation from HTML to texinfo
+ in time for GCC 3.0.
+
+* Krister Walfridsson for random bug fixes.
+
+* Feng Wang for contributions to GNU Fortran.
+
+* Stephen M. Webb for time and effort on making libstdc++ shadow files
+ work with the tricky Solaris 8+ headers, and for pushing the build-time
+ header tree. Also, for starting and driving the ``<regex>`` effort.
+
+* John Wehle for various improvements for the x86 code generator,
+ related infrastructure improvements to help x86 code generation,
+ value range propagation and other work, WE32k port.
+
+* Ulrich Weigand for work on the s390 port.
+
+* Janus Weil for contributions to GNU Fortran.
+
+* Zack Weinberg for major work on cpplib and various other bug fixes.
+
+* Matt Welsh for help with Linux Threads support in GCJ.
+
+* Urban Widmark for help fixing java.io.
+
+* Mark Wielaard for new Java library code and his work integrating with
+ Classpath.
+
+* Dale Wiles helped port GCC to the Tahoe.
+
+* Bob Wilson from Tensilica, Inc. for the Xtensa port.
+
+* Jim Wilson for his direction via the steering committee, tackling hard
+ problems in various places that nobody else wanted to work on, strength
+ reduction and other loop optimizations.
+
+* Paul Woegerer and Tal Agmon for the CRX port.
+
+* Carlo Wood for various fixes.
+
+* Tom Wood for work on the m88k port.
+
+* Chung-Ju Wu for his work on the Andes NDS32 port.
+
+* Canqun Yang for work on GNU Fortran.
+
+* Masanobu Yuhara of Fujitsu Laboratories implemented the machine
+ description for the Tron architecture (specifically, the Gmicro).
+
+* Kevin Zachmann helped port GCC to the Tahoe.
+
+* Ayal Zaks for Swing Modulo Scheduling (SMS).
+
+* Qirun Zhang for running automated regression testing of GCC and reporting
+ numerous bugs.
+
+* Xiaoqiang Zhang for work on GNU Fortran.
+
+* Gilles Zunino for help porting Java to Irix.
+
+The following people are recognized for their contributions to GNAT,
+the Ada front end of GCC:
+
+* Bernard Banner
+
+* Romain Berrendonner
+
+* Geert Bosch
+
+* Emmanuel Briot
+
+* Joel Brobecker
+
+* Ben Brosgol
+
+* Vincent Celier
+
+* Arnaud Charlet
+
+* Chien Chieng
+
+* Cyrille Comar
+
+* Cyrille Crozes
+
+* Robert Dewar
+
+* Gary Dismukes
+
+* Robert Duff
+
+* Ed Falis
+
+* Ramon Fernandez
+
+* Sam Figueroa
+
+* Vasiliy Fofanov
+
+* Michael Friess
+
+* Franco Gasperoni
+
+* Ted Giering
+
+* Matthew Gingell
+
+* Laurent Guerby
+
+* Jerome Guitton
+
+* Olivier Hainque
+
+* Jerome Hugues
+
+* Hristian Kirtchev
+
+* Jerome Lambourg
+
+* Bruno Leclerc
+
+* Albert Lee
+
+* Sean McNeil
+
+* Javier Miranda
+
+* Laurent Nana
+
+* Pascal Obry
+
+* Dong-Ik Oh
+
+* Laurent Pautet
+
+* Brett Porter
+
+* Thomas Quinot
+
+* Nicolas Roche
+
+* Pat Rogers
+
+* Jose Ruiz
+
+* Douglas Rupp
+
+* Sergey Rybin
+
+* Gail Schenker
+
+* Ed Schonberg
+
+* Nicolas Setton
+
+* Samuel Tardieu
+
+The following people are recognized for their contributions of new
+features, bug reports, testing and integration of classpath/libgcj for
+GCC version 4.1:
+
+* Lillian Angel for ``JTree`` implementation and lots Free Swing
+ additions and bug fixes.
+
+* Wolfgang Baer for ``GapContent`` bug fixes.
+
+* Anthony Balkissoon for ``JList``, Free Swing 1.5 updates and mouse event
+ fixes, lots of Free Swing work including ``JTable`` editing.
+
+* Stuart Ballard for RMI constant fixes.
+
+* Goffredo Baroncelli for ``HTTPURLConnection`` fixes.
+
+* Gary Benson for ``MessageFormat`` fixes.
+
+* Daniel Bonniot for ``Serialization`` fixes.
+
+* Chris Burdess for lots of gnu.xml and http protocol fixes, ``StAX``
+ and ``DOM xml:id`` support.
+
+* Ka-Hing Cheung for ``TreePath`` and ``TreeSelection`` fixes.
+
+* Archie Cobbs for build fixes, VM interface updates,
+ ``URLClassLoader`` updates.
+
+* Kelley Cook for build fixes.
+
+* Martin Cordova for Suggestions for better ``SocketTimeoutException``.
+
+* David Daney for ``BitSet`` bug fixes, ``HttpURLConnection``
+ rewrite and improvements.
+
+* Thomas Fitzsimmons for lots of upgrades to the gtk+ AWT and Cairo 2D
+ support. Lots of imageio framework additions, lots of AWT and Free
+ Swing bug fixes.
+
+* Jeroen Frijters for ``ClassLoader`` and nio cleanups, serialization fixes,
+ better ``Proxy`` support, bug fixes and IKVM integration.
+
+* Santiago Gala for ``AccessControlContext`` fixes.
+
+* Nicolas Geoffray for ``VMClassLoader`` and ``AccessController``
+ improvements.
+
+* David Gilbert for ``basic`` and ``metal`` icon and plaf support
+ and lots of documenting, Lots of Free Swing and metal theme
+ additions. ``MetalIconFactory`` implementation.
+
+* Anthony Green for ``MIDI`` framework, ``ALSA`` and ``DSSI``
+ providers.
+
+* Andrew Haley for ``Serialization`` and ``URLClassLoader`` fixes,
+ gcj build speedups.
+
+* Kim Ho for ``JFileChooser`` implementation.
+
+* Andrew John Hughes for ``Locale`` and net fixes, URI RFC2986
+ updates, ``Serialization`` fixes, ``Properties`` XML support and
+ generic branch work, VMIntegration guide update.
+
+* Bastiaan Huisman for ``TimeZone`` bug fixing.
+
+* Andreas Jaeger for mprec updates.
+
+* Paul Jenner for better :option:`-Werror` support.
+
+* Ito Kazumitsu for ``NetworkInterface`` implementation and updates.
+
+* Roman Kennke for ``BoxLayout``, ``GrayFilter`` and
+ ``SplitPane``, plus bug fixes all over. Lots of Free Swing work
+ including styled text.
+
+* Simon Kitching for ``String`` cleanups and optimization suggestions.
+
+* Michael Koch for configuration fixes, ``Locale`` updates, bug and
+ build fixes.
+
+* Guilhem Lavaux for configuration, thread and channel fixes and Kaffe
+ integration. JCL native ``Pointer`` updates. Logger bug fixes.
+
+* David Lichteblau for JCL support library global/local reference
+ cleanups.
+
+* Aaron Luchko for JDWP updates and documentation fixes.
+
+* Ziga Mahkovec for ``Graphics2D`` upgraded to Cairo 0.5 and new regex
+ features.
+
+* Sven de Marothy for BMP imageio support, CSS and ``TextLayout``
+ fixes. ``GtkImage`` rewrite, 2D, awt, free swing and date/time fixes and
+ implementing the Qt4 peers.
+
+* Casey Marshall for crypto algorithm fixes, ``FileChannel`` lock,
+ ``SystemLogger`` and ``FileHandler`` rotate implementations, NIO
+ ``FileChannel.map`` support, security and policy updates.
+
+* Bryce McKinlay for RMI work.
+
+* Audrius Meskauskas for lots of Free Corba, RMI and HTML work plus
+ testing and documenting.
+
+* Kalle Olavi Niemitalo for build fixes.
+
+* Rainer Orth for build fixes.
+
+* Andrew Overholt for ``File`` locking fixes.
+
+* Ingo Proetel for ``Image``, ``Logger`` and ``URLClassLoader``
+ updates.
+
+* Olga Rodimina for ``MenuSelectionManager`` implementation.
+
+* Jan Roehrich for ``BasicTreeUI`` and ``JTree`` fixes.
+
+* Julian Scheid for documentation updates and gjdoc support.
+
+* Christian Schlichtherle for zip fixes and cleanups.
+
+* Robert Schuster for documentation updates and beans fixes,
+ ``TreeNode`` enumerations and ``ActionCommand`` and various
+ fixes, XML and URL, AWT and Free Swing bug fixes.
+
+* Keith Seitz for lots of JDWP work.
+
+* Christian Thalinger for 64-bit cleanups, Configuration and VM
+ interface fixes and ``CACAO`` integration, ``fdlibm`` updates.
+
+* Gael Thomas for ``VMClassLoader`` boot packages support suggestions.
+
+* Andreas Tobler for Darwin and Solaris testing and fixing, ``Qt4``
+ support for Darwin/OS X, ``Graphics2D`` support, ``gtk+``
+ updates.
+
+* Dalibor Topic for better ``DEBUG`` support, build cleanups and
+ Kaffe integration. ``Qt4`` build infrastructure, ``SHA1PRNG``
+ and ``GdkPixbugDecoder`` updates.
+
+* Tom Tromey for Eclipse integration, generics work, lots of bug fixes
+ and gcj integration including coordinating The Big Merge.
+
+* Mark Wielaard for bug fixes, packaging and release management,
+ ``Clipboard`` implementation, system call interrupts and network
+ timeouts and ``GdkPixpufDecoder`` fixes.
+
+In addition to the above, all of which also contributed time and energy in
+testing GCC, we would like to thank the following for their contributions
+to testing:
+
+* Michael Abd-El-Malek
+
+* Thomas Arend
+
+* Bonzo Armstrong
+
+* Steven Ashe
+
+* Chris Baldwin
+
+* David Billinghurst
+
+* Jim Blandy
+
+* Stephane Bortzmeyer
+
+* Horst von Brand
+
+* Frank Braun
+
+* Rodney Brown
+
+* Sidney Cadot
+
+* Bradford Castalia
+
+* Robert Clark
+
+* Jonathan Corbet
+
+* Ralph Doncaster
+
+* Richard Emberson
+
+* Levente Farkas
+
+* Graham Fawcett
+
+* Mark Fernyhough
+
+* Robert A. French
+
+* Jörgen Freyh
+
+* Mark K. Gardner
+
+* Charles-Antoine Gauthier
+
+* Yung Shing Gene
+
+* David Gilbert
+
+* Simon Gornall
+
+* Fred Gray
+
+* John Griffin
+
+* Patrik Hagglund
+
+* Phil Hargett
+
+* Amancio Hasty
+
+* Takafumi Hayashi
+
+* Bryan W. Headley
+
+* Kevin B. Hendricks
+
+* Joep Jansen
+
+* Christian Joensson
+
+* Michel Kern
+
+* David Kidd
+
+* Tobias Kuipers
+
+* Anand Krishnaswamy
+
+* A. O. V. Le Blanc
+
+* llewelly
+
+* Damon Love
+
+* Brad Lucier
+
+* Matthias Klose
+
+* Martin Knoblauch
+
+* Rick Lutowski
+
+* Jesse Macnish
+
+* Stefan Morrell
+
+* Anon A. Mous
+
+* Matthias Mueller
+
+* Pekka Nikander
+
+* Rick Niles
+
+* Jon Olson
+
+* Magnus Persson
+
+* Chris Pollard
+
+* Richard Polton
+
+* Derk Reefman
+
+* David Rees
+
+* Paul Reilly
+
+* Tom Reilly
+
+* Torsten Rueger
+
+* Danny Sadinoff
+
+* Marc Schifer
+
+* Erik Schnetter
+
+* Wayne K. Schroll
+
+* David Schuler
+
+* Vin Shelton
+
+* Tim Souder
+
+* Adam Sulmicki
+
+* Bill Thorson
+
+* George Talbot
+
+* Pedro A. M. Vazquez
+
+* Gregory Warnes
+
+* Ian Watson
+
+* David E. Young
+
+* And many others
+
+And finally we'd like to thank everyone who uses the compiler, provides
+feedback and generally reminds us why we're doing this work in the first
+place.
+
+.. -
+ Indexes
+ -
\ No newline at end of file
diff --git a/doc/contribute.rst b/doc/contribute.rst
new file mode 100644
index 00000000000..45e0c5f340c
--- /dev/null
+++ b/doc/contribute.rst
@@ -0,0 +1,26 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _contributing:
+
+Contributing to GCC Development
+-------------------------------
+
+If you would like to help pretest GCC releases to assure they work well,
+current development sources are available via Git (see
+http://gcc.gnu.org/git.html). Source and binary snapshots are
+also available for FTP; see http://gcc.gnu.org/snapshots.html.
+
+If you would like to work on improvements to GCC, please read the
+advice at these URLs:
+
+.. code-block:: c++
+
+ http://gcc.gnu.org/contribute.html
+ http://gcc.gnu.org/contributewhy.html
+
+for information on how to make useful contributions and avoid
+duplication of effort. Suggested projects are listed at
+http://gcc.gnu.org/projects/.
\ No newline at end of file
diff --git a/doc/copyright.rst b/doc/copyright.rst
new file mode 100644
index 00000000000..c28243a85e2
--- /dev/null
+++ b/doc/copyright.rst
@@ -0,0 +1,25 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+Copyright
+^^^^^^^^^
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.3 or
+any later version published by the Free Software Foundation; with the
+Invariant Sections being **GNU General Public License** and
+**Funding Free Software**, the Front-Cover texts being (a) (see below), and with
+the Back-Cover Texts being (b) (see below). A copy of the license is
+included in the gfdl(7) man page.
+
+(a) The FSF's Front-Cover Text is:
+
+ A GNU Manual
+
+(b) The FSF's Back-Cover Text is:
+
+ You have freedom to copy and modify this GNU Manual, like GNU
+ software. Copies published by the Free Software Foundation raise
+ funds for GNU development.
\ No newline at end of file
diff --git a/doc/cppdiropts.rst b/doc/cppdiropts.rst
new file mode 100644
index 00000000000..d00f69f67b9
--- /dev/null
+++ b/doc/cppdiropts.rst
@@ -0,0 +1,215 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. option:: -I dir, -iquote dir, -isystem dir, -idirafter dir
+
+ Add the directory :samp:`{dir}` to the list of directories to be searched
+ for header files during preprocessing.
+
+ .. only:: cpp
+
+ See :ref:`search-path`.
+
+ If :samp:`{dir}` begins with :samp:`=` or ``$SYSROOT``, then the :samp:`=`
+ or ``$SYSROOT`` is replaced by the sysroot prefix; see
+ :option:`--sysroot` and :option:`-isysroot`.
+
+ Directories specified with :option:`-iquote` apply only to the quote
+ form of the directive, ``#include "file"``.
+ Directories specified with :option:`-I`, :option:`-isystem`,
+ or :option:`-idirafter` apply to lookup for both the
+ ``#include "file"`` and
+ ``#include <file>`` directives.
+
+ You can specify any number or combination of these options on the
+ command line to search for header files in several directories.
+ The lookup order is as follows:
+
+ * For the quote form of the include directive, the directory of the current
+ file is searched first.
+
+ * For the quote form of the include directive, the directories specified
+ by :option:`-iquote` options are searched in left-to-right order,
+ as they appear on the command line.
+
+ * Directories specified with :option:`-I` options are scanned in
+ left-to-right order.
+
+ * Directories specified with :option:`-isystem` options are scanned in
+ left-to-right order.
+
+ * Standard system directories are scanned.
+
+ * Directories specified with :option:`-idirafter` options are scanned in
+ left-to-right order.
+
+ You can use :option:`-I` to override a system header
+ file, substituting your own version, since these directories are
+ searched before the standard system header file directories.
+ However, you should
+ not use this option to add directories that contain vendor-supplied
+ system header files; use :option:`-isystem` for that.
+
+ The :option:`-isystem` and :option:`-idirafter` options also mark the directory
+ as a system directory, so that it gets the same special treatment that
+ is applied to the standard system directories.
+
+ .. only:: cpp
+
+ See :ref:`system-headers`.
+
+
+ If a standard system include directory, or a directory specified with
+ :option:`-isystem`, is also specified with :option:`-I`, the :option:`-I`
+ option is ignored. The directory is still searched but as a
+ system directory at its normal position in the system include chain.
+ This is to ensure that GCC's procedure to fix buggy system headers and
+ the ordering for the ``#include_next`` directive are not inadvertently
+ changed.
+ If you really need to change the search order for system directories,
+ use the :option:`-nostdinc` and/or :option:`-isystem` options.
+
+ .. only:: cpp
+
+ See :ref:`system-headers`.
+
+
+.. option:: -I-
+
+ Split the include path.
+ This option has been deprecated. Please use :option:`-iquote` instead for
+ :option:`-I` directories before the :option:`-I-` and remove the :option:`-I-`
+ option.
+
+ Any directories specified with :option:`-I`
+ options before :option:`-I-` are searched only for headers requested with
+ ``#include "file"`` ; they are not searched for
+ ``#include <file>``. If additional directories are
+ specified with :option:`-I` options after the :option:`-I-`, those
+ directories are searched for all :samp:`#include` directives.
+
+ In addition, :option:`-I-` inhibits the use of the directory of the current
+ file directory as the first search directory for ``#include
+ "file"``. There is no way to override this effect of :option:`-I-`.
+
+ .. only:: cpp
+
+ See :ref:`search-path`.
+
+
+.. option:: -iprefix prefix
+
+ Specify :samp:`{prefix}` as the prefix for subsequent :option:`-iwithprefix`
+ options. If the prefix represents a directory, you should include the
+ final :samp:`/`.
+
+.. option:: -iwithprefix dir, -iwithprefixbefore dir
+
+ Append :samp:`{dir}` to the prefix specified previously with
+ :option:`-iprefix`, and add the resulting directory to the include search
+ path. :option:`-iwithprefixbefore` puts it in the same place :option:`-I`
+ would; :option:`-iwithprefix` puts it where :option:`-idirafter` would.
+
+.. option:: -isysroot dir
+
+ This option is like the :option:`--sysroot` option, but applies only to
+ header files (except for Darwin targets, where it applies to both header
+ files and libraries). See the :option:`--sysroot` option for more
+ information.
+
+.. option:: -imultilib dir
+
+ Use :samp:`{dir}` as a subdirectory of the directory containing
+ target-specific C++ headers.
+
+.. option:: -nostdinc
+
+ Do not search the standard system directories for header files.
+ Only the directories explicitly specified with :option:`-I`,
+ :option:`-iquote`, :option:`-isystem`, and/or :option:`-idirafter`
+ options (and the directory of the current file, if appropriate)
+ are searched.
+
+.. option:: -nostdinc++
+
+ Do not search for header files in the C++-specific standard directories,
+ but do still search the other standard directories. (This option is
+ used when building the C++ library.)
+
+.. option:: -Wcomment, -Wcomments
+
+ Warn whenever a comment-start sequence :samp:`/*` appears in a :samp:`/*`
+ comment, or whenever a backslash-newline appears in a :samp:`//` comment.
+ This warning is enabled by :option:`-Wall`.
+
+.. option:: -Wtrigraphs
+
+.. _wtrigraphs:
+
+ Warn if any trigraphs are encountered that might change the meaning of
+ the program. Trigraphs within comments are not warned about,
+ except those that would form escaped newlines.
+
+ This option is implied by :option:`-Wall`. If :option:`-Wall` is not
+ given, this option is still enabled unless trigraphs are enabled. To
+ get trigraph conversion without warnings, but get the other
+ :option:`-Wall` warnings, use :samp:`-trigraphs -Wall -Wno-trigraphs`.
+
+.. option:: -Wundef
+
+ Warn if an undefined identifier is evaluated in an ``#if`` directive.
+ Such identifiers are replaced with zero.
+
+.. option:: -Wno-undef
+
+ Default option value for :option:`-Wundef`.
+
+.. option:: -Wexpansion-to-defined
+
+ Warn whenever :samp:`defined` is encountered in the expansion of a macro
+ (including the case where the macro is expanded by an :samp:`#if` directive).
+ Such usage is not portable.
+ This warning is also enabled by :option:`-Wpedantic` and :option:`-Wextra`.
+
+.. option:: -Wunused-macros
+
+ Warn about macros defined in the main file that are unused. A macro
+ is :dfn:`used` if it is expanded or tested for existence at least once.
+ The preprocessor also warns if the macro has not been used at the
+ time it is redefined or undefined.
+
+ Built-in macros, macros defined on the command line, and macros
+ defined in include files are not warned about.
+
+ *Note:* If a macro is actually used, but only used in skipped
+ conditional blocks, then the preprocessor reports it as unused. To avoid the
+ warning in such a case, you might improve the scope of the macro's
+ definition by, for example, moving it into the first skipped block.
+ Alternatively, you could provide a dummy use with something like:
+
+ .. code-block:: c++
+
+ #if defined the_macro_causing_the_warning
+ #endif
+
+.. option:: -Wno-endif-labels
+
+ Do not warn whenever an ``#else`` or an ``#endif`` are followed by text.
+ This sometimes happens in older programs with code of the form
+
+ .. code-block:: c++
+
+ #if FOO
+ ...
+ #else FOO
+ ...
+ #endif FOO
+
+ The second and third ``FOO`` should be in comments.
+ This warning is on by default.
+
+.. option:: -Wendif-labels
+
+ Default option value for :option:`-Wno-endif-labels`.
\ No newline at end of file
diff --git a/doc/cppenv.rst b/doc/cppenv.rst
new file mode 100644
index 00000000000..9d035bb1125
--- /dev/null
+++ b/doc/cppenv.rst
@@ -0,0 +1,97 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. envvar:: CPATH, C_INCLUDE_PATH, CPLUS_INCLUDE_PATH, OBJC_INCLUDE_PATH
+
+ .. Commented out until ObjC++ is part of GCC:
+ @itemx OBJCPLUS_INCLUDE_PATH
+
+ Each variable's value is a list of directories separated by a special
+ character, much like :envvar:`PATH`, in which to look for header files.
+ The special character, ``PATH_SEPARATOR``, is target-dependent and
+ determined at GCC build time. For Microsoft Windows-based targets it is a
+ semicolon, and for almost all other targets it is a colon.
+
+ :envvar:`CPATH` specifies a list of directories to be searched as if
+ specified with :option:`-I`, but after any paths given with :option:`-I`
+ options on the command line. This environment variable is used
+ regardless of which language is being preprocessed.
+
+ The remaining environment variables apply only when preprocessing the
+ particular language indicated. Each specifies a list of directories
+ to be searched as if specified with :option:`-isystem`, but after any
+ paths given with :option:`-isystem` options on the command line.
+
+ In all these variables, an empty element instructs the compiler to
+ search its current working directory. Empty elements can appear at the
+ beginning or end of a path. For instance, if the value of
+ :envvar:`CPATH` is ``:/special/include``, that has the same
+ effect as :samp:`-I. -I/special/include`.
+
+ .. only:: cpp
+
+ See also Search Path.
+
+.. envvar:: DEPENDENCIES_OUTPUT
+
+ .. index:: dependencies for make as output
+
+ If this variable is set, its value specifies how to output
+ dependencies for Make based on the non-system header files processed
+ by the compiler. System header files are ignored in the dependency
+ output.
+
+ The value of :envvar:`DEPENDENCIES_OUTPUT` can be just a file name, in
+ which case the Make rules are written to that file, guessing the target
+ name from the source file name. Or the value can have the form
+ :samp:`{file}{target}`, in which case the rules are written to
+ file :samp:`{file}` using :samp:`{target}` as the target name.
+
+ In other words, this environment variable is equivalent to combining
+ the options :option:`-MM` and :option:`-MF`
+
+ .. only:: cpp
+
+ (see :ref:`invocation`),
+
+ .. only:: not cpp
+
+ (see :ref:`preprocessor-options`),
+
+ with an optional :option:`-MT` switch too.
+
+.. envvar:: SUNPRO_DEPENDENCIES
+
+ .. index:: dependencies for make as output
+
+ This variable is the same as :envvar:`DEPENDENCIES_OUTPUT` (see above),
+ except that system header files are not ignored, so it implies
+ :option:`-M` rather than :option:`-MM`. However, the dependence on the
+ main input file is omitted.
+
+ .. only:: cpp
+
+ See :ref:`invocation`.
+
+ .. only:: not cpp
+
+ See :ref:`preprocessor-options`.
+
+.. envvar:: SOURCE_DATE_EPOCH
+
+ If this variable is set, its value specifies a UNIX timestamp to be
+ used in replacement of the current date and time in the ``__DATE__``
+ and ``__TIME__`` macros, so that the embedded timestamps become
+ reproducible.
+
+ The value of :envvar:`SOURCE_DATE_EPOCH` must be a UNIX timestamp,
+ defined as the number of seconds (excluding leap seconds) since
+ 01 Jan 1970 00:00:00 represented in ASCII; identical to the output of
+ ``date +%s`` on GNU/Linux and other systems that support the
+ ``%s`` extension in the ``date`` command.
+
+ The value should be a known timestamp such as the last modification
+ time of the source or package and it should be set by the build
+ process.
\ No newline at end of file
diff --git a/doc/cppopts.rst b/doc/cppopts.rst
new file mode 100644
index 00000000000..aed3d972d5f
--- /dev/null
+++ b/doc/cppopts.rst
@@ -0,0 +1,559 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. option:: -D name
+
+ Predefine :samp:`{name}` as a macro, with definition ``1``.
+
+:samp:`-D {name}={definition}`
+ The contents of :samp:`{definition}` are tokenized and processed as if
+ they appeared during translation phase three in a :samp:`#define`
+ directive. In particular, the definition is truncated by
+ embedded newline characters.
+
+ If you are invoking the preprocessor from a shell or shell-like
+ program you may need to use the shell's quoting syntax to protect
+ characters such as spaces that have a meaning in the shell syntax.
+
+ If you wish to define a function-like macro on the command line, write
+ its argument list with surrounding parentheses before the equals sign
+ (if any). Parentheses are meaningful to most shells, so you should
+ quote the option. With :command:`sh` and :command:`csh`,
+ :option:`-D'`:samp:`{name}` ( :samp:`{args...}` )= :samp:`{definition}` ' works.
+
+ :option:`-D` and :option:`-U` options are processed in the order they
+ are given on the command line. All :option:`-imacros` :samp:`{file}` and
+ :option:`-include` :samp:`{file}` options are processed after all
+ :option:`-D` and :option:`-U` options.
+
+.. option:: -U name
+
+ Cancel any previous definition of :samp:`{name}`, either built in or
+ provided with a :option:`-D` option.
+
+.. option:: -include file
+
+ Process :samp:`{file}` as if ``#include "file"`` appeared as the first
+ line of the primary source file. However, the first directory searched
+ for :samp:`{file}` is the preprocessor's working directory *instead of*
+ the directory containing the main source file. If not found there, it
+ is searched for in the remainder of the ``#include "..."`` search
+ chain as normal.
+
+ If multiple :option:`-include` options are given, the files are included
+ in the order they appear on the command line.
+
+.. option:: -imacros file
+
+ Exactly like :option:`-include`, except that any output produced by
+ scanning :samp:`{file}` is thrown away. Macros it defines remain defined.
+ This allows you to acquire all the macros from a header without also
+ processing its declarations.
+
+ All files specified by :option:`-imacros` are processed before all files
+ specified by :option:`-include`.
+
+.. option:: -undef
+
+ Do not predefine any system-specific or GCC-specific macros. The
+ standard predefined macros remain defined.
+
+ .. only:: cpp
+
+ See :ref:`standard-predefined-macros`.
+
+.. option:: -pthread
+
+ Define additional macros required for using the POSIX threads library.
+ You should use this option consistently for both compilation and linking.
+ This option is supported on GNU/Linux targets, most other Unix derivatives,
+ and also on x86 Cygwin and MinGW targets.
+
+.. option:: -M
+
+ .. index:: make
+
+ .. index:: dependencies, make
+
+ Instead of outputting the result of preprocessing, output a rule
+ suitable for :command:`make` describing the dependencies of the main
+ source file. The preprocessor outputs one :command:`make` rule containing
+ the object file name for that source file, a colon, and the names of all
+ the included files, including those coming from :option:`-include` or
+ :option:`-imacros` command-line options.
+
+ Unless specified explicitly (with :option:`-MT` or :option:`-MQ` ), the
+ object file name consists of the name of the source file with any
+ suffix replaced with object file suffix and with any leading directory
+ parts removed. If there are many included files then the rule is
+ split into several lines using :samp:`\\` -newline. The rule has no
+ commands.
+
+ This option does not suppress the preprocessor's debug output, such as
+ :option:`-dM`. To avoid mixing such debug output with the dependency
+ rules you should explicitly specify the dependency output file with
+ :option:`-MF`, or use an environment variable like
+ :envvar:`DEPENDENCIES_OUTPUT` (see :ref:`environment-variables`). Debug output
+ is still sent to the regular output stream as normal.
+
+ Passing :option:`-M` to the driver implies :option:`-E`, and suppresses
+ warnings with an implicit :option:`-w`.
+
+.. option:: -MM
+
+ Like :option:`-M` but do not mention header files that are found in
+ system header directories, nor header files that are included,
+ directly or indirectly, from such a header.
+
+ This implies that the choice of angle brackets or double quotes in an
+ :samp:`#include` directive does not in itself determine whether that
+ header appears in :option:`-MM` dependency output.
+
+.. option:: -MF file
+
+ When used with :option:`-M` or :option:`-MM`, specifies a
+ file to write the dependencies to. If no :option:`-MF` switch is given
+ the preprocessor sends the rules to the same place it would send
+ preprocessed output.
+
+ When used with the driver options :option:`-MD` or :option:`-MMD`,
+ :option:`-MF` overrides the default dependency output file.
+
+ If :samp:`{file}` is :samp:`-`, then the dependencies are written to :samp:`stdout`.
+
+.. option:: -MG
+
+ In conjunction with an option such as :option:`-M` requesting
+ dependency generation, :option:`-MG` assumes missing header files are
+ generated files and adds them to the dependency list without raising
+ an error. The dependency filename is taken directly from the
+ ``#include`` directive without prepending any path. :option:`-MG`
+ also suppresses preprocessed output, as a missing header file renders
+ this useless.
+
+ This feature is used in automatic updating of makefiles.
+
+.. option:: -Mno-modules
+
+ Disable dependency generation for compiled module interfaces.
+
+.. option:: -MP
+
+ This option instructs CPP to add a phony target for each dependency
+ other than the main file, causing each to depend on nothing. These
+ dummy rules work around errors :command:`make` gives if you remove header
+ files without updating the :samp:`Makefile` to match.
+
+ This is typical output:
+
+ .. code-block:: c++
+
+ test.o: test.c test.h
+
+ test.h:
+
+.. option:: -MT target
+
+ Change the target of the rule emitted by dependency generation. By
+ default CPP takes the name of the main input file, deletes any
+ directory components and any file suffix such as :samp:`.c`, and
+ appends the platform's usual object suffix. The result is the target.
+
+ An :option:`-MT` option sets the target to be exactly the string you
+ specify. If you want multiple targets, you can specify them as a single
+ argument to :option:`-MT`, or use multiple :option:`-MT` options.
+
+ For example, -MT '$(objpfx)foo.o' might give
+
+ .. code-block:: c++
+
+ $(objpfx)foo.o: foo.c
+
+.. option:: -MQ target
+
+ Same as :option:`-MT`, but it quotes any characters which are special to
+ Make. -MQ '$(objpfx)foo.o' gives
+
+ .. code-block:: c++
+
+ $$(objpfx)foo.o: foo.c
+
+ The default target is automatically quoted, as if it were given with
+ :option:`-MQ`.
+
+.. option:: -MD
+
+ :option:`-MD` is equivalent to :option:`-M -MF` :samp:`{file}`, except that
+ :option:`-E` is not implied. The driver determines :samp:`{file}` based on
+ whether an :option:`-o` option is given. If it is, the driver uses its
+ argument but with a suffix of :samp:`.d`, otherwise it takes the name
+ of the input file, removes any directory components and suffix, and
+ applies a :samp:`.d` suffix.
+
+ If :option:`-MD` is used in conjunction with :option:`-E`, any
+ :option:`-o` switch is understood to specify the dependency output file
+ (see :ref:`-MF <dashmf>`), but if used without :option:`-E`, each :option:`-o`
+ is understood to specify a target object file.
+
+ Since :option:`-E` is not implied, :option:`-MD` can be used to generate
+ a dependency output file as a side effect of the compilation process.
+
+.. option:: -MMD
+
+ Like :option:`-MD` except mention only user header files, not system
+ header files.
+
+.. option:: -fpreprocessed
+
+ Indicate to the preprocessor that the input file has already been
+ preprocessed. This suppresses things like macro expansion, trigraph
+ conversion, escaped newline splicing, and processing of most directives.
+ The preprocessor still recognizes and removes comments, so that you can
+ pass a file preprocessed with :option:`-C` to the compiler without
+ problems. In this mode the integrated preprocessor is little more than
+ a tokenizer for the front ends.
+
+ :option:`-fpreprocessed` is implicit if the input file has one of the
+ extensions :samp:`.i`, :samp:`.ii` or :samp:`.mi`. These are the
+ extensions that GCC uses for preprocessed files created by
+ :option:`-save-temps`.
+
+.. option:: -fdirectives-only
+
+ When preprocessing, handle directives, but do not expand macros.
+
+ The option's behavior depends on the :option:`-E` and :option:`-fpreprocessed`
+ options.
+
+ With :option:`-E`, preprocessing is limited to the handling of directives
+ such as ``#define``, ``#ifdef``, and ``#error``. Other
+ preprocessor operations, such as macro expansion and trigraph
+ conversion are not performed. In addition, the :option:`-dD` option is
+ implicitly enabled.
+
+ With :option:`-fpreprocessed`, predefinition of command line and most
+ builtin macros is disabled. Macros such as ``__LINE__``, which are
+ contextually dependent, are handled normally. This enables compilation of
+ files previously preprocessed with ``-E -fdirectives-only``.
+
+ With both :option:`-E` and :option:`-fpreprocessed`, the rules for
+ :option:`-fpreprocessed` take precedence. This enables full preprocessing of
+ files previously preprocessed with ``-E -fdirectives-only``.
+
+.. option:: -fdollars-in-identifiers
+
+.. _fdollars-in-identifiers:
+
+ Accept :samp:`$` in identifiers.
+
+ .. only:: cpp
+
+ See :ref:`identifier-characters`.
+
+.. option:: -fextended-identifiers
+
+ Accept universal character names and extended characters in
+ identifiers. This option is enabled by default for C99 (and later C
+ standard versions) and C++.
+
+.. option:: -fno-canonical-system-headers
+
+ When preprocessing, do not shorten system header paths with canonicalization.
+
+.. option:: -fmax-include-depth=depth
+
+ Set the maximum depth of the nested #include. The default is 200.
+
+.. option:: -ftabstop=width
+
+ Set the distance between tab stops. This helps the preprocessor report
+ correct column numbers in warnings or errors, even if tabs appear on the
+ line. If the value is less than 1 or greater than 100, the option is
+ ignored. The default is 8.
+
+.. option:: -ftrack-macro-expansion[=level]
+
+ Track locations of tokens across macro expansions. This allows the
+ compiler to emit diagnostic about the current macro expansion stack
+ when a compilation error occurs in a macro expansion. Using this
+ option makes the preprocessor and the compiler consume more
+ memory. The :samp:`{level}` parameter can be used to choose the level of
+ precision of token location tracking thus decreasing the memory
+ consumption if necessary. Value :samp:`0` of :samp:`{level}` de-activates
+ this option. Value :samp:`1` tracks tokens locations in a
+ degraded mode for the sake of minimal memory overhead. In this mode
+ all tokens resulting from the expansion of an argument of a
+ function-like macro have the same location. Value :samp:`2` tracks
+ tokens locations completely. This value is the most memory hungry.
+ When this option is given no argument, the default parameter value is
+ :samp:`2`.
+
+ Note that ``-ftrack-macro-expansion=2`` is activated by default.
+
+.. option:: -fmacro-prefix-map=old=new
+
+ When preprocessing files residing in directory :samp:`{old}`,
+ expand the ``__FILE__`` and ``__BASE_FILE__`` macros as if the
+ files resided in directory :samp:`{new}` instead. This can be used
+ to change an absolute path to a relative path by using :samp:`.` for
+ :samp:`{new}` which can result in more reproducible builds that are
+ location independent. This option also affects
+ ``__builtin_FILE()`` during compilation. See also
+ :option:`-ffile-prefix-map`.
+
+.. option:: -fexec-charset=charset
+
+ .. index:: character set, execution
+
+ Set the execution character set, used for string and character
+ constants. The default is UTF-8. :samp:`{charset}` can be any encoding
+ supported by the system's ``iconv`` library routine.
+
+.. option:: -fwide-exec-charset=charset
+
+ .. index:: character set, wide execution
+
+ Set the wide execution character set, used for wide string and
+ character constants. The default is UTF-32 or UTF-16, whichever
+ corresponds to the width of ``wchar_t``. As with
+ :option:`-fexec-charset`, :samp:`{charset}` can be any encoding supported
+ by the system's ``iconv`` library routine; however, you will have
+ problems with encodings that do not fit exactly in ``wchar_t``.
+
+.. option:: -finput-charset=charset
+
+ .. index:: character set, input
+
+ Set the input character set, used for translation from the character
+ set of the input file to the source character set used by GCC. If the
+ locale does not specify, or GCC cannot get this information from the
+ locale, the default is UTF-8. This can be overridden by either the locale
+ or this command-line option. Currently the command-line option takes
+ precedence if there's a conflict. :samp:`{charset}` can be any encoding
+ supported by the system's ``iconv`` library routine.
+
+.. only:: not cpp
+
+ .. option:: -fpch-deps
+
+ When using precompiled headers (see :ref:`precompiled-headers`), this flag
+ causes the dependency-output flags to also list the files from the
+ precompiled header's dependencies. If not specified, only the
+ precompiled header are listed and not the files that were used to
+ create it, because those files are not consulted when a precompiled
+ header is used.
+
+ .. option:: -fpch-preprocess
+
+ This option allows use of a precompiled header (see :ref:`precompiled-headers`) together with :option:`-E`. It inserts a special ``#pragma``,
+ ``#pragma GCC pch_preprocess "filename"`` in the output to mark
+ the place where the precompiled header was found, and its :samp:`{filename}`.
+ When :option:`-fpreprocessed` is in use, GCC recognizes this ``#pragma``
+ and loads the PCH.
+
+ This option is off by default, because the resulting preprocessed output
+ is only really suitable as input to GCC. It is switched on by
+ :option:`-save-temps`.
+
+ You should not write this ``#pragma`` in your own code, but it is
+ safe to edit the filename if the PCH file is available in a different
+ location. The filename may be absolute or it may be relative to GCC's
+ current directory.
+
+.. option:: -fworking-directory
+
+ Enable generation of linemarkers in the preprocessor output that
+ let the compiler know the current working directory at the time of
+ preprocessing. When this option is enabled, the preprocessor
+ emits, after the initial linemarker, a second linemarker with the
+ current working directory followed by two slashes. GCC uses this
+ directory, when it's present in the preprocessed input, as the
+ directory emitted as the current working directory in some debugging
+ information formats. This option is implicitly enabled if debugging
+ information is enabled, but this can be inhibited with the negated
+ form :option:`-fno-working-directory`. If the :option:`-P` flag is
+ present in the command line, this option has no effect, since no
+ ``#line`` directives are emitted whatsoever.
+
+.. option:: -fno-working-directory
+
+ Default option value for :option:`-fworking-directory`.
+
+.. option:: -A predicate=answer
+
+ Make an assertion with the predicate :samp:`{predicate}` and answer
+ :samp:`{answer}`. This form is preferred to the older form :option:`-A`
+ :samp:`{predicate}` ( :samp:`{answer}` ), which is still supported, because
+ it does not use shell special characters.
+
+ .. only:: cpp
+
+ See :ref:`obsolete-features`.
+
+:samp:`-A -{predicate}={answer}`
+ Cancel an assertion with the predicate :samp:`{predicate}` and answer
+ :samp:`{answer}`.
+
+.. option:: -C
+
+ Do not discard comments. All comments are passed through to the output
+ file, except for comments in processed directives, which are deleted
+ along with the directive.
+
+ You should be prepared for side effects when using :option:`-C` ; it
+ causes the preprocessor to treat comments as tokens in their own right.
+ For example, comments appearing at the start of what would be a
+ directive line have the effect of turning that line into an ordinary
+ source line, since the first token on the line is no longer a :samp:`#`.
+
+.. option:: -CC
+
+ Do not discard comments, including during macro expansion. This is
+ like :option:`-C`, except that comments contained within macros are
+ also passed through to the output file where the macro is expanded.
+
+ In addition to the side effects of the :option:`-C` option, the
+ :option:`-CC` option causes all C++-style comments inside a macro
+ to be converted to C-style comments. This is to prevent later use
+ of that macro from inadvertently commenting out the remainder of
+ the source line.
+
+ The :option:`-CC` option is generally used to support lint comments.
+
+.. option:: -P
+
+ Inhibit generation of linemarkers in the output from the preprocessor.
+ This might be useful when running the preprocessor on something that is
+ not C code, and will be sent to a program which might be confused by the
+ linemarkers.
+
+ .. only:: cpp
+
+ See :ref:`preprocessor-output`.
+
+ .. index:: traditional C language
+
+ .. index:: C language, traditional
+
+.. option:: -traditional, -traditional-cpp
+
+ Try to imitate the behavior of pre-standard C preprocessors, as
+ opposed to ISO C preprocessors.
+
+ .. only:: cpp
+
+ See :ref:`traditional-mode`.
+
+ .. only:: not cpp
+
+ See the GNU CPP manual for details.
+
+ Note that GCC does not otherwise attempt to emulate a pre-standard
+ C compiler, and these options are only supported with the :option:`-E`
+ switch, or when invoking CPP explicitly.
+
+.. option:: -trigraphs
+
+ Support ISO C trigraphs.
+ These are three-character sequences, all starting with :samp:`??`, that
+ are defined by ISO C to stand for single characters. For example,
+ :samp:`??/` stands for :samp:`\\`, so :samp:`??/n` is a character
+ constant for a newline.
+
+ .. only:: cpp
+
+ See :ref:`initial-processing`.
+
+ .. only:: not cpp
+
+ The nine trigraphs and their replacements are
+
+ .. code-block::
+
+ Trigraph: ??( ??) ??< ??> ??= ??/ ??' ??! ??-
+ Replacement: [ ] { } # \ ^ | ~
+
+ By default, GCC ignores trigraphs, but in
+ standard-conforming modes it converts them. See the :option:`-std` and
+ :option:`-ansi` options.
+
+.. option:: -remap
+
+ Enable special code to work around file systems which only permit very
+ short file names, such as MS-DOS.
+
+.. option:: -H
+
+ Print the name of each header file used, in addition to other normal
+ activities. Each name is indented to show how deep in the
+ :samp:`#include` stack it is. Precompiled header files are also
+ printed, even if they are found to be invalid; an invalid precompiled
+ header file is printed with :samp:`...x` and a valid one with :samp:`...!` .
+
+.. option:: -dletters
+
+ Says to make debugging dumps during compilation as specified by
+ :samp:`{letters}`. The flags documented here are those relevant to the
+ preprocessor. Other :samp:`{letters}` are interpreted
+ by the compiler proper, or reserved for future versions of GCC, and so
+ are silently ignored. If you specify :samp:`{letters}` whose behavior
+ conflicts, the result is undefined.
+
+ .. only:: not cpp
+
+ See :ref:`developer-options`, for more information.
+
+ .. option:: -dM
+
+ Instead of the normal output, generate a list of :samp:`#define`
+ directives for all the macros defined during the execution of the
+ preprocessor, including predefined macros. This gives you a way of
+ finding out what is predefined in your version of the preprocessor.
+ Assuming you have no file :samp:`foo.h`, the command
+
+ .. code-block:: c++
+
+ touch foo.h; cpp -dM foo.h
+
+ shows all the predefined macros.
+
+ .. only:: cpp
+
+ If you use :option:`-dM` without the :option:`-E` option, :option:`-dM` is
+ interpreted as a synonym for :option:`-fdump-rtl-mach`.
+ See :ref:`developer-options`.
+
+ .. option:: -dD
+
+ Like :option:`-dM` except in two respects: it does *not* include the
+ predefined macros, and it outputs *both* the :samp:`#define`
+ directives and the result of preprocessing. Both kinds of output go to
+ the standard output file.
+
+ .. option:: -dN
+
+ Like :option:`-dD`, but emit only the macro names, not their expansions.
+
+ .. option:: -dI
+
+ Output :samp:`#include` directives in addition to the result of
+ preprocessing.
+
+ .. option:: -dU
+
+ Like :option:`-dD` except that only macros that are expanded, or whose
+ definedness is tested in preprocessor directives, are output; the
+ output is delayed until the use or test of the macro; and
+ :samp:`#undef` directives are also output for macros tested but
+ undefined at the time.
+
+.. option:: -fdebug-cpp
+
+ This option is only useful for debugging GCC. When used from CPP or with
+ :option:`-E`, it dumps debugging information about location maps. Every
+ token in the output is preceded by the dump of the map its location
+ belongs to.
+
+ When used from GCC without :option:`-E`, this option has no effect.
\ No newline at end of file
diff --git a/doc/cppwarnopts.rst b/doc/cppwarnopts.rst
new file mode 100644
index 00000000000..4814ff34eb9
--- /dev/null
+++ b/doc/cppwarnopts.rst
@@ -0,0 +1,4 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
\ No newline at end of file
diff --git a/doc/funding.rst b/doc/funding.rst
new file mode 100644
index 00000000000..245e3d4bf22
--- /dev/null
+++ b/doc/funding.rst
@@ -0,0 +1,47 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+Funding Free Software
+=====================
+
+If you want to have more free software a few years from now, it makes
+sense for you to help encourage people to contribute funds for its
+development. The most effective approach known is to encourage
+commercial redistributors to donate.
+
+Users of free software systems can boost the pace of development by
+encouraging for-a-fee distributors to donate part of their selling price
+to free software developers-the Free Software Foundation, and others.
+
+The way to convince distributors to do this is to demand it and expect
+it from them. So when you compare distributors, judge them partly by
+how much they give to free software development. Show distributors
+they must compete to be the one who gives the most.
+
+To make this approach work, you must insist on numbers that you can
+compare, such as, 'We will donate ten dollars to the Frobnitz project
+for each disk sold.' Don't be satisfied with a vague promise, such as
+'A portion of the profits are donated,' since it doesn't give a basis
+for comparison.
+
+Even a precise fraction 'of the profits from this disk' is not very
+meaningful, since creative accounting and unrelated business decisions
+can greatly alter what fraction of the sales price counts as profit.
+If the price you pay is $50, ten percent of the profit is probably
+less than a dollar; it might be a few cents, or nothing at all.
+
+Some redistributors do development work themselves. This is useful too;
+but to keep everyone honest, you need to inquire how much they do, and
+what kind. Some kinds of development make much more long-term
+difference than others. For example, maintaining a separate version of
+a program contributes very little; maintaining the standard version of a
+program for the whole community contributes much. Easy new ports
+contribute little, since someone else would surely do them; difficult
+ports such as adding a new CPU to the GNU Compiler Collection contribute more;
+major new features or packages contribute the most.
+
+By establishing the idea that supporting further development is 'the
+proper thing to do' when distributing free software for a fee, we can
+assure a steady flow of resources into making more free software.
\ No newline at end of file
diff --git a/doc/gnu.rst b/doc/gnu.rst
new file mode 100644
index 00000000000..8003f925c4c
--- /dev/null
+++ b/doc/gnu.rst
@@ -0,0 +1,24 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _gnu-project:
+
+The GNU Project and GNU/Linux
+=============================
+
+The GNU Project was launched in 1984 to develop a complete Unix-like
+operating system which is free software: the GNU system. (GNU is a
+recursive acronym for 'GNU's Not Unix'; it is pronounced
+'guh-NEW'.) Variants of the GNU operating system, which use the
+kernel Linux, are now widely used; though these systems are often
+referred to as 'Linux', they are more accurately called GNU/Linux
+systems.
+
+For more information, see:
+
+.. code-block:: c++
+
+ http://www.gnu.org/
+ http://www.gnu.org/gnu/linux-and-gnu.html
\ No newline at end of file
diff --git a/doc/gnu_free_documentation_license.rst b/doc/gnu_free_documentation_license.rst
new file mode 100644
index 00000000000..d12a088fc14
--- /dev/null
+++ b/doc/gnu_free_documentation_license.rst
@@ -0,0 +1,463 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _gnu_fdl:
+
+******************************
+GNU Free Documentation License
+******************************
+
+Version 1.3, 3 November 2008
+
+Copyright 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc
+http://fsf.org/
+
+Everyone is permitted to copy and distribute verbatim copies of this
+license document, but changing it is not allowed.
+
+**Preamble**
+
+The purpose of this License is to make a manual, textbook, or other
+functional and useful document "free" in the sense of freedom: to
+assure everyone the effective freedom to copy and redistribute it,
+with or without modifying it, either commercially or noncommercially.
+Secondarily, this License preserves for the author and publisher a way
+to get credit for their work, while not being considered responsible
+for modifications made by others.
+
+This License is a kind of "copyleft", which means that derivative
+works of the document must themselves be free in the same sense. It
+complements the GNU General Public License, which is a copyleft
+license designed for free software.
+
+We have designed this License in order to use it for manuals for free
+software, because free software needs free documentation: a free
+program should come with manuals providing the same freedoms that the
+software does. But this License is not limited to software manuals;
+it can be used for any textual work, regardless of subject matter or
+whether it is published as a printed book. We recommend this License
+principally for works whose purpose is instruction or reference.
+
+**1. APPLICABILITY AND DEFINITIONS**
+
+This License applies to any manual or other work, in any medium, that
+contains a notice placed by the copyright holder saying it can be
+distributed under the terms of this License. Such a notice grants a
+world-wide, royalty-free license, unlimited in duration, to use that
+work under the conditions stated herein. The **Document**, below,
+refers to any such manual or work. Any member of the public is a
+licensee, and is addressed as "**you**". You accept the license if you
+copy, modify or distribute the work in a way requiring permission
+under copyright law.
+
+A "**Modified Version**" of the Document means any work containing the
+Document or a portion of it, either copied verbatim, or with
+modifications and/or translated into another language.
+
+A "**Secondary Section**" is a named appendix or a front-matter section of
+the Document that deals exclusively with the relationship of the
+publishers or authors of the Document to the Document's overall subject
+(or to related matters) and contains nothing that could fall directly
+within that overall subject. (Thus, if the Document is in part a
+textbook of mathematics, a Secondary Section may not explain any
+mathematics.) The relationship could be a matter of historical
+connection with the subject or with related matters, or of legal,
+commercial, philosophical, ethical or political position regarding
+them.
+
+The "**Invariant Sections**" are certain Secondary Sections whose titles
+are designated, as being those of Invariant Sections, in the notice
+that says that the Document is released under this License. If a
+section does not fit the above definition of Secondary then it is not
+allowed to be designated as Invariant. The Document may contain zero
+Invariant Sections. If the Document does not identify any Invariant
+Sections then there are none.
+
+The "**Cover Texts**" are certain short passages of text that are listed,
+as Front-Cover Texts or Back-Cover Texts, in the notice that says that
+the Document is released under this License. A Front-Cover Text may
+be at most 5 words, and a Back-Cover Text may be at most 25 words.
+
+A "**Transparent**" copy of the Document means a machine-readable copy,
+represented in a format whose specification is available to the
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+drawing editor, and that is suitable for input to text formatters or
+for automatic translation to a variety of formats suitable for input
+to text formatters. A copy made in an otherwise Transparent file
+format whose markup, or absence of markup, has been arranged to thwart
+or discourage subsequent modification by readers is not Transparent.
+An image format is not Transparent if used for any substantial amount
+of text. A copy that is not "Transparent" is called **Opaque**.
+
+Examples of suitable formats for Transparent copies include plain
+ASCII without markup, Texinfo input format, LaTeX input format, SGML
+or XML using a publicly available DTD, and standard-conforming simple
+HTML, PostScript or PDF designed for human modification. Examples of
+transparent image formats include PNG, XCF and JPG. Opaque formats
+include proprietary formats that can be read and edited only by
+proprietary word processors, SGML or XML for which the DTD and/or
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+machine-generated HTML, PostScript or PDF produced by some word
+processors for output purposes only.
+
+The "**Title Page**" means, for a printed book, the title page itself,
+plus such following pages as are needed to hold, legibly, the material
+this License requires to appear in the title page. For works in
+formats which do not have any title page as such, "Title Page" means
+the text near the most prominent appearance of the work's title,
+preceding the beginning of the body of the text.
+
+The "**publisher**" means any person or entity that distributes
+copies of the Document to the public.
+
+A section "**Entitled XYZ**" means a named subunit of the Document whose
+title either is precisely XYZ or contains XYZ in parentheses following
+text that translates XYZ in another language. (Here XYZ stands for a
+specific section name mentioned below, such as "**Acknowledgements**",
+"**Dedications**", "**Endorsements**", or "**History**".)
+To "**Preserve the Title**"
+of such a section when you modify the Document means that it remains a
+section "Entitled XYZ" according to this definition.
+
+The Document may include Warranty Disclaimers next to the notice which
+states that this License applies to the Document. These Warranty
+Disclaimers are considered to be included by reference in this
+License, but only as regards disclaiming warranties: any other
+implication that these Warranty Disclaimers may have is void and has
+no effect on the meaning of this License.
+
+**2. VERBATIM COPYING**
+
+You may copy and distribute the Document in any medium, either
+commercially or noncommercially, provided that this License, the
+copyright notices, and the license notice saying this License applies
+to the Document are reproduced in all copies, and that you add no other
+conditions whatsoever to those of this License. You may not use
+technical measures to obstruct or control the reading or further
+copying of the copies you make or distribute. However, you may accept
+compensation in exchange for copies. If you distribute a large enough
+number of copies you must also follow the conditions in section 3.
+
+You may also lend copies, under the same conditions stated above, and
+you may publicly display copies.
+
+**3. COPYING IN QUANTITY**
+
+If you publish printed copies (or copies in media that commonly have
+printed covers) of the Document, numbering more than 100, and the
+Document's license notice requires Cover Texts, you must enclose the
+copies in covers that carry, clearly and legibly, all these Cover
+Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
+the back cover. Both covers must also clearly and legibly identify
+you as the publisher of these copies. The front cover must present
+the full title with all words of the title equally prominent and
+visible. You may add other material on the covers in addition.
+Copying with changes limited to the covers, as long as they preserve
+the title of the Document and satisfy these conditions, can be treated
+as verbatim copying in other respects.
+
+If the required texts for either cover are too voluminous to fit
+legibly, you should put the first ones listed (as many as fit
+reasonably) on the actual cover, and continue the rest onto adjacent
+pages.
+
+If you publish or distribute Opaque copies of the Document numbering
+more than 100, you must either include a machine-readable Transparent
+copy along with each Opaque copy, or state in or with each Opaque copy
+a computer-network location from which the general network-using
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+that this Transparent copy will remain thus accessible at the stated
+location until at least one year after the last time you distribute an
+Opaque copy (directly or through your agents or retailers) of that
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+
+It is requested, but not required, that you contact the authors of the
+Document well before redistributing any large number of copies, to give
+them a chance to provide you with an updated version of the Document.
+
+**4. MODIFICATIONS**
+
+You may copy and distribute a Modified Version of the Document under
+the conditions of sections 2 and 3 above, provided that you release
+the Modified Version under precisely this License, with the Modified
+Version filling the role of the Document, thus licensing distribution
+and modification of the Modified Version to whoever possesses a copy
+of it. In addition, you must do these things in the Modified Version:
+
+A. Use in the Title Page (and on the covers, if any) a title distinct
+ from that of the Document, and from those of previous versions
+ (which should, if there were any, be listed in the History section
+ of the Document). You may use the same title as a previous version
+ if the original publisher of that version gives permission.
+
+B. List on the Title Page, as authors, one or more persons or entities
+ responsible for authorship of the modifications in the Modified
+ Version, together with at least five of the principal authors of the
+ Document (all of its principal authors, if it has fewer than five),
+ unless they release you from this requirement.
+
+C. State on the Title page the name of the publisher of the
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+D. Preserve all the copyright notices of the Document.
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+ Preserve the Title of the section, and preserve in the section all
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+A compilation of the Document or its derivatives with other separate
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+distribution medium, is called an "aggregate" if the copyright
+resulting from the compilation is not used to limit the legal rights
+of the compilation's users beyond what the individual works permit.
+When the Document is included in an aggregate, this License does not
+apply to the other works in the aggregate which are not themselves
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+or disclaimer, the original version will prevail.
+
+If a section in the Document is Entitled "Acknowledgements",
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+its Title (section 1) will typically require changing the actual
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+**9. TERMINATION**
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+You may not copy, modify, sublicense, or distribute the Document
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+will automatically terminate your rights under this License.
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+However, if you cease all violation of this License, then your license
+from a particular copyright holder is reinstated (a) provisionally,
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+received notice of violation of this License (for any work) from that
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+Termination of your rights under this section does not terminate the
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+not give you any rights to use it.
+
+**10. FUTURE REVISIONS OF THIS LICENSE**
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+The Free Software Foundation may publish new, revised versions
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+http://www.gnu.org/copyleft/.
+
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+If the Document specifies that a particular numbered version of this
+License "or any later version" applies to it, you have the option of
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+**11. RELICENSING**
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+"Incorporate" means to publish or republish a Document, in whole or
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+provided the MMC is eligible for relicensing.
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+**ADDENDUM: How to use this License for your documents**
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+To use this License in a document you have written, include a copy of
+the License in the document and put the following copyright and
+license notices just after the title page:
+
+ Copyright © YEAR YOUR NAME.
+ Permission is granted to copy, distribute and/or modify this document
+ under the terms of the GNU Free Documentation License, Version 1.3
+ or any later version published by the Free Software Foundation;
+ with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
+ A copy of the license is included in the section entitled "GNU
+ Free Documentation License".
+
+
+If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
+replace the "with ... Texts." line with this:
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+If you have Invariant Sections without Cover Texts, or some other
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+If your document contains nontrivial examples of program code, we
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+to permit their use in free software.
\ No newline at end of file
diff --git a/doc/gpl-3.0.rst b/doc/gpl-3.0.rst
new file mode 100644
index 00000000000..058a049da17
--- /dev/null
+++ b/doc/gpl-3.0.rst
@@ -0,0 +1,707 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+GNU GENERAL PUBLIC LICENSE
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Version 3, 29 June 2007
+
+Copyright (C) 2007 Free Software Foundation, Inc. https://fsf.org/
+
+Everyone is permitted to copy and distribute verbatim copies of this
+license document, but changing it is not allowed.
+
+Preamble
+########
+
+The GNU General Public License is a free, copyleft license for software
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+For example, if you distribute copies of such a program, whether gratis
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+TERMS AND CONDITIONS
+####################
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\ No newline at end of file
diff --git a/doc/lgpl-2.1.rst b/doc/lgpl-2.1.rst
new file mode 100644
index 00000000000..a4c346be676
--- /dev/null
+++ b/doc/lgpl-2.1.rst
@@ -0,0 +1,512 @@
+..
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\ No newline at end of file
diff --git a/doc/md.rst b/doc/md.rst
new file mode 100644
index 00000000000..e0b19b276c6
--- /dev/null
+++ b/doc/md.rst
@@ -0,0 +1,3272 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _simple-constraints:
+
+Simple Constraints
+^^^^^^^^^^^^^^^^^^
+
+.. index:: simple constraints
+
+The simplest kind of constraint is a string full of letters, each of
+which describes one kind of operand that is permitted. Here are
+the letters that are allowed:
+
+whitespace
+ Whitespace characters are ignored and can be inserted at any position
+ except the first. This enables each alternative for different operands to
+ be visually aligned in the machine description even if they have different
+ number of constraints and modifiers.
+
+ .. index:: m in constraint
+
+ .. index:: memory references in constraints
+
+m
+ A memory operand is allowed, with any kind of address that the machine
+ supports in general.
+ Note that the letter used for the general memory constraint can be
+ re-defined by a back end using the ``TARGET_MEM_CONSTRAINT`` macro.
+
+ .. index:: offsettable address
+
+ .. index:: o in constraint
+
+o
+ A memory operand is allowed, but only if the address is
+ :dfn:`offsettable`. This means that adding a small integer (actually,
+ the width in bytes of the operand, as determined by its machine mode)
+ may be added to the address and the result is also a valid memory
+ address.
+
+ .. index:: autoincrement/decrement addressing
+
+ For example, an address which is constant is offsettable; so is an
+ address that is the sum of a register and a constant (as long as a
+ slightly larger constant is also within the range of address-offsets
+ supported by the machine); but an autoincrement or autodecrement
+ address is not offsettable. More complicated indirect/indexed
+ addresses may or may not be offsettable depending on the other
+ addressing modes that the machine supports.
+
+ Note that in an output operand which can be matched by another
+ operand, the constraint letter :samp:`o` is valid only when accompanied
+ by both :samp:`<` (if the target machine has predecrement addressing)
+ and :samp:`>` (if the target machine has preincrement addressing).
+
+ .. index:: V in constraint
+
+V
+ A memory operand that is not offsettable. In other words, anything that
+ would fit the :samp:`m` constraint but not the :samp:`o` constraint.
+
+ .. index:: < in constraint
+
+<
+ A memory operand with autodecrement addressing (either predecrement or
+ postdecrement) is allowed. In inline ``asm`` this constraint is only
+ allowed if the operand is used exactly once in an instruction that can
+ handle the side effects. Not using an operand with :samp:`<` in constraint
+ string in the inline ``asm`` pattern at all or using it in multiple
+ instructions isn't valid, because the side effects wouldn't be performed
+ or would be performed more than once. Furthermore, on some targets
+ the operand with :samp:`<` in constraint string must be accompanied by
+ special instruction suffixes like ``%U0`` instruction suffix on PowerPC
+ or ``%P0`` on IA-64.
+
+ .. index:: > in constraint
+
+>
+ A memory operand with autoincrement addressing (either preincrement or
+ postincrement) is allowed. In inline ``asm`` the same restrictions
+ as for :samp:`<` apply.
+
+ .. index:: r in constraint
+
+ .. index:: registers in constraints
+
+r
+ A register operand is allowed provided that it is in a general
+ register.
+
+ .. index:: constants in constraints
+
+ .. index:: i in constraint
+
+i
+ An immediate integer operand (one with constant value) is allowed.
+ This includes symbolic constants whose values will be known only at
+ assembly time or later.
+
+ .. index:: n in constraint
+
+n
+ An immediate integer operand with a known numeric value is allowed.
+ Many systems cannot support assembly-time constants for operands less
+ than a word wide. Constraints for these operands should use :samp:`n`
+ rather than :samp:`i`.
+
+ .. index:: I in constraint
+
+:samp:`{I}, {J}, {K}, ... {P}`
+ Other letters in the range :samp:`I` through :samp:`P` may be defined in
+ a machine-dependent fashion to permit immediate integer operands with
+ explicit integer values in specified ranges. For example, on the
+ 68000, :samp:`I` is defined to stand for the range of values 1 to 8.
+ This is the range permitted as a shift count in the shift
+ instructions.
+
+ .. index:: E in constraint
+
+E
+ An immediate floating operand (expression code ``const_double`` ) is
+ allowed, but only if the target floating point format is the same as
+ that of the host machine (on which the compiler is running).
+
+ .. index:: F in constraint
+
+F
+ An immediate floating operand (expression code ``const_double`` or
+ ``const_vector`` ) is allowed.
+
+ .. index:: G in constraint
+
+ .. index:: H in constraint
+
+:samp:`{G}, {H}`
+ :samp:`G` and :samp:`H` may be defined in a machine-dependent fashion to
+ permit immediate floating operands in particular ranges of values.
+
+ .. index:: s in constraint
+
+s
+ An immediate integer operand whose value is not an explicit integer is
+ allowed.
+
+ This might appear strange; if an insn allows a constant operand with a
+ value not known at compile time, it certainly must allow any known
+ value. So why use :samp:`s` instead of :samp:`i`? Sometimes it allows
+ better code to be generated.
+
+ For example, on the 68000 in a fullword instruction it is possible to
+ use an immediate operand; but if the immediate value is between -128
+ and 127, better code results from loading the value into a register and
+ using the register. This is because the load into the register can be
+ done with a :samp:`moveq` instruction. We arrange for this to happen
+ by defining the letter :samp:`K` to mean 'any integer outside the
+ range -128 to 127', and then specifying :samp:`Ks` in the operand
+ constraints.
+
+ .. index:: g in constraint
+
+g
+ Any register, memory or immediate integer operand is allowed, except for
+ registers that are not general registers.
+
+ .. index:: X in constraint
+
+X
+
+ .. only:: gccint
+
+ Any operand whatsoever is allowed, even if it does not satisfy
+ ``general_operand``. This is normally used in the constraint of
+ a ``match_scratch`` when certain alternatives will not actually
+ require a scratch register.
+
+ .. only:: not gccint
+
+ Any operand whatsoever is allowed.
+
+ .. index:: 0 in constraint
+
+ .. index:: digits in constraint
+
+:samp:`{0}, {1}, {2}, ... {9}`
+ An operand that matches the specified operand number is allowed. If a
+ digit is used together with letters within the same alternative, the
+ digit should come last.
+
+ This number is allowed to be more than a single digit. If multiple
+ digits are encountered consecutively, they are interpreted as a single
+ decimal integer. There is scant chance for ambiguity, since to-date
+ it has never been desirable that :samp:`10` be interpreted as matching
+ either operand 1 *or* operand 0. Should this be desired, one
+ can use multiple alternatives instead.
+
+ .. index:: matching constraint
+
+ .. index:: constraint, matching
+
+ This is called a :dfn:`matching constraint` and what it really means is
+ that the assembler has only a single operand that fills two roles
+
+ .. only:: gccint
+
+ considered separate in the RTL insn. For example, an add insn has two
+ input operands and one output operand in the RTL, but on most CISC
+
+ .. only:: not gccint
+
+ which ``asm`` distinguishes. For example, an add instruction uses
+ two input operands and an output operand, but on most CISC
+
+ machines an add instruction really has only two operands, one of them an
+ input-output operand:
+
+ .. code-block::
+
+ addl #35,r12
+
+ Matching constraints are used in these circumstances.
+ More precisely, the two operands that match must include one input-only
+ operand and one output-only operand. Moreover, the digit must be a
+ smaller number than the number of the operand that uses it in the
+ constraint.
+
+ .. only:: gccint
+
+ For operands to match in a particular case usually means that they
+ are identical-looking RTL expressions. But in a few special cases
+ specific kinds of dissimilarity are allowed. For example, ``*x``
+ as an input operand will match ``*x++`` as an output operand.
+ For proper results in such cases, the output template should always
+ use the output-operand's number when printing the operand.
+
+ .. index:: load address instruction
+
+ .. index:: push address instruction
+
+ .. index:: address constraints
+
+ .. index:: p in constraint
+
+p
+ An operand that is a valid memory address is allowed. This is
+ for 'load address' and 'push address' instructions.
+
+ .. index:: address_operand
+
+ :samp:`p` in the constraint must be accompanied by ``address_operand``
+ as the predicate in the ``match_operand``. This predicate interprets
+ the mode specified in the ``match_operand`` as the mode of the memory
+ reference for which the address would be valid.
+
+ .. index:: other register constraints
+
+ .. index:: extensible constraints
+
+other-letters
+ Other letters can be defined in machine-dependent fashion to stand for
+ particular classes of registers or other arbitrary operand types.
+ :samp:`d`, :samp:`a` and :samp:`f` are defined on the 68000/68020 to stand
+ for data, address and floating point registers.
+
+.. only:: gccint
+
+ In order to have valid assembler code, each operand must satisfy
+ its constraint. But a failure to do so does not prevent the pattern
+ from applying to an insn. Instead, it directs the compiler to modify
+ the code so that the constraint will be satisfied. Usually this is
+ done by copying an operand into a register.
+
+ Contrast, therefore, the two instruction patterns that follow:
+
+ .. code-block:: c++
+
+ (define_insn ""
+ [(set (match_operand:SI 0 "general_operand" "=r")
+ (plus:SI (match_dup 0)
+ (match_operand:SI 1 "general_operand" "r")))]
+ ""
+ "...")
+
+ which has two operands, one of which must appear in two places, and
+
+ .. code-block:: c++
+
+ (define_insn ""
+ [(set (match_operand:SI 0 "general_operand" "=r")
+ (plus:SI (match_operand:SI 1 "general_operand" "0")
+ (match_operand:SI 2 "general_operand" "r")))]
+ ""
+ "...")
+
+ which has three operands, two of which are required by a constraint to be
+ identical. If we are considering an insn of the form
+
+ .. code-block:: c++
+
+ (insn n prev next
+ (set (reg:SI 3)
+ (plus:SI (reg:SI 6) (reg:SI 109)))
+ ...)
+
+ the first pattern would not apply at all, because this insn does not
+ contain two identical subexpressions in the right place. The pattern would
+ say, 'That does not look like an add instruction; try other patterns'.
+ The second pattern would say, 'Yes, that's an add instruction, but there
+ is something wrong with it'. It would direct the reload pass of the
+ compiler to generate additional insns to make the constraint true. The
+ results might look like this:
+
+ .. code-block:: c++
+
+ (insn n2 prev n
+ (set (reg:SI 3) (reg:SI 6))
+ ...)
+
+ (insn n n2 next
+ (set (reg:SI 3)
+ (plus:SI (reg:SI 3) (reg:SI 109)))
+ ...)
+
+ It is up to you to make sure that each operand, in each pattern, has
+ constraints that can handle any RTL expression that could be present for
+ that operand. (When multiple alternatives are in use, each pattern must,
+ for each possible combination of operand expressions, have at least one
+ alternative which can handle that combination of operands.) The
+ constraints don't need to *allow* any possible operand---when this is
+ the case, they do not constrain---but they must at least point the way to
+ reloading any possible operand so that it will fit.
+
+ * If the constraint accepts whatever operands the predicate permits,
+ there is no problem: reloading is never necessary for this operand.
+
+ For example, an operand whose constraints permit everything except
+ registers is safe provided its predicate rejects registers.
+
+ An operand whose predicate accepts only constant values is safe
+ provided its constraints include the letter :samp:`i`. If any possible
+ constant value is accepted, then nothing less than :samp:`i` will do;
+ if the predicate is more selective, then the constraints may also be
+ more selective.
+
+ * Any operand expression can be reloaded by copying it into a register.
+ So if an operand's constraints allow some kind of register, it is
+ certain to be safe. It need not permit all classes of registers; the
+ compiler knows how to copy a register into another register of the
+ proper class in order to make an instruction valid.
+
+ .. index:: nonoffsettable memory reference
+
+ .. index:: memory reference, nonoffsettable
+
+ * A nonoffsettable memory reference can be reloaded by copying the
+ address into a register. So if the constraint uses the letter
+ :samp:`o`, all memory references are taken care of.
+
+ * A constant operand can be reloaded by allocating space in memory to
+ hold it as preinitialized data. Then the memory reference can be used
+ in place of the constant. So if the constraint uses the letters
+ :samp:`o` or :samp:`m`, constant operands are not a problem.
+
+ * If the constraint permits a constant and a pseudo register used in an insn
+ was not allocated to a hard register and is equivalent to a constant,
+ the register will be replaced with the constant. If the predicate does
+ not permit a constant and the insn is re-recognized for some reason, the
+ compiler will crash. Thus the predicate must always recognize any
+ objects allowed by the constraint.
+
+ If the operand's predicate can recognize registers, but the constraint does
+ not permit them, it can make the compiler crash. When this operand happens
+ to be a register, the reload pass will be stymied, because it does not know
+ how to copy a register temporarily into memory.
+
+ If the predicate accepts a unary operator, the constraint applies to the
+ operand. For example, the MIPS processor at ISA level 3 supports an
+ instruction which adds two registers in ``SImode`` to produce a
+ ``DImode`` result, but only if the registers are correctly sign
+ extended. This predicate for the input operands accepts a
+ ``sign_extend`` of an ``SImode`` register. Write the constraint
+ to indicate the type of register that is required for the operand of the
+ ``sign_extend``.
+
+.. only:: not gccint
+
+ So the first alternative for the 68000's logical-or could be written as
+ ``"+m" (output) : "ir" (input)``. The second could be ``"+r"
+ (output): "irm" (input)``. However, the fact that two memory locations
+ cannot be used in a single instruction prevents simply using ``"+rm"
+ (output) : "irm" (input)``. Using multi-alternatives, this might be
+ written as ``"+m,r" (output) : "ir,irm" (input)``. This describes
+ all the available alternatives to the compiler, allowing it to choose
+ the most efficient one for the current conditions.
+
+ There is no way within the template to determine which alternative was
+ chosen. However you may be able to wrap your ``asm`` statements with
+ builtins such as ``__builtin_constant_p`` to achieve the desired results.
+
+.. _multi-alternative:
+
+Multiple Alternative Constraints
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: multiple alternative constraints
+
+Sometimes a single instruction has multiple alternative sets of possible
+operands. For example, on the 68000, a logical-or instruction can combine
+register or an immediate value into memory, or it can combine any kind of
+operand into a register; but it cannot combine one memory location into
+another.
+
+These constraints are represented as multiple alternatives. An alternative
+can be described by a series of letters for each operand. The overall
+constraint for an operand is made from the letters for this operand
+from the first alternative, a comma, the letters for this operand from
+the second alternative, a comma, and so on until the last alternative.
+All operands for a single instruction must have the same number of
+alternatives.
+
+.. only:: gccint
+
+ Here is how it is done for fullword logical-or on the 68000:
+
+ .. code-block:: c++
+
+ (define_insn "iorsi3"
+ [(set (match_operand:SI 0 "general_operand" "=m,d")
+ (ior:SI (match_operand:SI 1 "general_operand" "%0,0")
+ (match_operand:SI 2 "general_operand" "dKs,dmKs")))]
+ ...)
+
+ The first alternative has :samp:`m` (memory) for operand 0, :samp:`0` for
+ operand 1 (meaning it must match operand 0), and :samp:`dKs` for operand
+ 2. The second alternative has :samp:`d` (data register) for operand 0,
+ :samp:`0` for operand 1, and :samp:`dmKs` for operand 2. The :samp:`=` and
+ :samp:`%` in the constraints apply to all the alternatives; their
+ meaning is explained in the next section (see :ref:`class-preferences`).
+
+ If all the operands fit any one alternative, the instruction is valid.
+ Otherwise, for each alternative, the compiler counts how many instructions
+ must be added to copy the operands so that that alternative applies.
+ The alternative requiring the least copying is chosen. If two alternatives
+ need the same amount of copying, the one that comes first is chosen.
+ These choices can be altered with the :samp:`?` and :samp:`!` characters:
+
+ .. index:: ? in constraint
+
+ .. index:: question mark
+
+ ``?``
+ Disparage slightly the alternative that the :samp:`?` appears in,
+ as a choice when no alternative applies exactly. The compiler regards
+ this alternative as one unit more costly for each :samp:`?` that appears
+ in it.
+
+ .. index:: ! in constraint
+
+ .. index:: exclamation point
+
+ ``!``
+ Disparage severely the alternative that the :samp:`!` appears in.
+ This alternative can still be used if it fits without reloading,
+ but if reloading is needed, some other alternative will be used.
+
+ .. index:: ^ in constraint
+
+ .. index:: caret
+
+ ``^``
+ This constraint is analogous to :samp:`?` but it disparages slightly
+ the alternative only if the operand with the :samp:`^` needs a reload.
+
+ .. index:: $ in constraint
+
+ .. index:: dollar sign
+
+ ``$``
+ This constraint is analogous to :samp:`!` but it disparages severely
+ the alternative only if the operand with the :samp:`$` needs a reload.
+
+ When an insn pattern has multiple alternatives in its constraints, often
+ the appearance of the assembler code is determined mostly by which
+ alternative was matched. When this is so, the C code for writing the
+ assembler code can use the variable ``which_alternative``, which is
+ the ordinal number of the alternative that was actually satisfied (0 for
+ the first, 1 for the second alternative, etc.). See :ref:`output-statement`.
+
+.. _class-preferences:
+
+Register Class Preferences
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. only:: gccint
+
+ .. index:: class preference constraints
+
+ .. index:: register class preference constraints
+
+ .. index:: voting between constraint alternatives
+
+ The operand constraints have another function: they enable the compiler
+ to decide which kind of hardware register a pseudo register is best
+ allocated to. The compiler examines the constraints that apply to the
+ insns that use the pseudo register, looking for the machine-dependent
+ letters such as :samp:`d` and :samp:`a` that specify classes of registers.
+ The pseudo register is put in whichever class gets the most 'votes'.
+ The constraint letters :samp:`g` and :samp:`r` also vote: they vote in
+ favor of a general register. The machine description says which registers
+ are considered general.
+
+ Of course, on some machines all registers are equivalent, and no register
+ classes are defined. Then none of this complexity is relevant.
+
+.. _modifiers:
+
+Constraint Modifier Characters
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: modifiers in constraints
+
+.. index:: constraint modifier characters
+
+.. prevent bad page break with this line
+
+Here are constraint modifier characters.
+
+.. index:: = in constraint
+
+:samp:`=`
+ Means that this operand is written to by this instruction:
+ the previous value is discarded and replaced by new data.
+
+ .. index:: + in constraint
+
+:samp:`+`
+ Means that this operand is both read and written by the instruction.
+
+ When the compiler fixes up the operands to satisfy the constraints,
+ it needs to know which operands are read by the instruction and
+ which are written by it. :samp:`=` identifies an operand which is only
+ written; :samp:`+` identifies an operand that is both read and written; all
+ other operands are assumed to only be read.
+
+ If you specify :samp:`=` or :samp:`+` in a constraint, you put it in the
+ first character of the constraint string.
+
+ .. index:: & in constraint
+
+ .. index:: earlyclobber operand
+
+:samp:`&`
+ Means (in a particular alternative) that this operand is an
+ :dfn:`earlyclobber` operand, which is written before the instruction is
+ finished using the input operands. Therefore, this operand may not lie
+ in a register that is read by the instruction or as part of any memory
+ address.
+
+ :samp:`&` applies only to the alternative in which it is written. In
+ constraints with multiple alternatives, sometimes one alternative
+ requires :samp:`&` while others do not. See, for example, the
+ :samp:`movdf` insn of the 68000.
+
+ An operand which is read by the instruction can be tied to an earlyclobber
+ operand if its only use as an input occurs before the early result is
+ written. Adding alternatives of this form often allows GCC to produce
+ better code when only some of the read operands can be affected by the
+ earlyclobber. See, for example, the :samp:`mulsi3` insn of the ARM.
+
+ Furthermore, if the :dfn:`earlyclobber` operand is also a read/write
+ operand, then that operand is written only after it's used.
+
+ :samp:`&` does not obviate the need to write :samp:`=` or :samp:`+`. As
+ :dfn:`earlyclobber` operands are always written, a read-only
+ :dfn:`earlyclobber` operand is ill-formed and will be rejected by the
+ compiler.
+
+ .. index:: % in constraint
+
+:samp:`%`
+ Declares the instruction to be commutative for this operand and the
+ following operand. This means that the compiler may interchange the
+ two operands if that is the cheapest way to make all operands fit the
+ constraints. :samp:`%` applies to all alternatives and must appear as
+ the first character in the constraint. Only read-only operands can use
+ :samp:`%`.
+
+ .. only:: gccint
+
+ This is often used in patterns for addition instructions
+ that really have only two operands: the result must go in one of the
+ arguments. Here for example, is how the 68000 halfword-add
+ instruction is defined:
+
+ .. code-block:: c++
+
+ (define_insn "addhi3"
+ [(set (match_operand:HI 0 "general_operand" "=m,r")
+ (plus:HI (match_operand:HI 1 "general_operand" "%0,0")
+ (match_operand:HI 2 "general_operand" "di,g")))]
+ ...)
+
+ GCC can only handle one commutative pair in an asm; if you use more,
+ the compiler may fail. Note that you need not use the modifier if
+ the two alternatives are strictly identical; this would only waste
+ time in the reload pass.
+
+ .. only:: gccint
+
+ The modifier is not operational after
+ register allocation, so the result of ``define_peephole2``
+ and ``define_split`` s performed after reload cannot rely on
+ :samp:`%` to make the intended insn match.
+
+ .. index:: # in constraint
+
+ :samp:`#`
+ Says that all following characters, up to the next comma, are to be
+ ignored as a constraint. They are significant only for choosing
+ register preferences.
+
+ .. index:: * in constraint
+
+ :samp:`*`
+ Says that the following character should be ignored when choosing
+ register preferences. :samp:`*` has no effect on the meaning of the
+ constraint as a constraint, and no effect on reloading. For LRA
+ :samp:`*` additionally disparages slightly the alternative if the
+ following character matches the operand.
+
+ Here is an example: the 68000 has an instruction to sign-extend a
+ halfword in a data register, and can also sign-extend a value by
+ copying it into an address register. While either kind of register is
+ acceptable, the constraints on an address-register destination are
+ less strict, so it is best if register allocation makes an address
+ register its goal. Therefore, :samp:`*` is used so that the :samp:`d`
+ constraint letter (for data register) is ignored when computing
+ register preferences.
+
+ .. code-block:: c++
+
+ (define_insn "extendhisi2"
+ [(set (match_operand:SI 0 "general_operand" "=*d,a")
+ (sign_extend:SI
+ (match_operand:HI 1 "general_operand" "0,g")))]
+ ...)
+
+ .. _machine-constraints:
+
+Constraints for Particular Machines
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: machine specific constraints
+
+.. index:: constraints, machine specific
+
+Whenever possible, you should use the general-purpose constraint letters
+in ``asm`` arguments, since they will convey meaning more readily to
+people reading your code. Failing that, use the constraint letters
+that usually have very similar meanings across architectures. The most
+commonly used constraints are :samp:`m` and :samp:`r` (for memory and
+general-purpose registers respectively; see :ref:`simple-constraints`), and
+:samp:`I`, usually the letter indicating the most common
+immediate-constant format.
+
+Each architecture defines additional constraints. These constraints
+are used by the compiler itself for instruction generation, as well as
+for ``asm`` statements; therefore, some of the constraints are not
+particularly useful for ``asm``. Here is a summary of some of the
+machine-dependent constraints available on some particular machines;
+it includes both constraints that are useful for ``asm`` and
+constraints that aren't. The compiler source file mentioned in the
+table heading for each architecture is the definitive reference for
+the meanings of that architecture's constraints.
+
+.. Please keep this table alphabetized by target!
+
+AArch64 family---:samp:`{config/aarch64/constraints.md}`
+
+ ``k``
+ The stack pointer register ( ``SP`` )
+
+ ``w``
+ Floating point register, Advanced SIMD vector register or SVE vector register
+
+ ``x``
+ Like ``w``, but restricted to registers 0 to 15 inclusive.
+
+ ``y``
+ Like ``w``, but restricted to registers 0 to 7 inclusive.
+
+ ``Upl``
+ One of the low eight SVE predicate registers ( ``P0`` to ``P7`` )
+
+ ``Upa``
+ Any of the SVE predicate registers ( ``P0`` to ``P15`` )
+
+ ``I``
+ Integer constant that is valid as an immediate operand in an ``ADD``
+ instruction
+
+ ``J``
+ Integer constant that is valid as an immediate operand in a ``SUB``
+ instruction (once negated)
+
+ ``K``
+ Integer constant that can be used with a 32-bit logical instruction
+
+ ``L``
+ Integer constant that can be used with a 64-bit logical instruction
+
+ ``M``
+ Integer constant that is valid as an immediate operand in a 32-bit ``MOV``
+ pseudo instruction. The ``MOV`` may be assembled to one of several different
+ machine instructions depending on the value
+
+ ``N``
+ Integer constant that is valid as an immediate operand in a 64-bit ``MOV``
+ pseudo instruction
+
+ ``S``
+ An absolute symbolic address or a label reference
+
+ ``Y``
+ Floating point constant zero
+
+ ``Z``
+ Integer constant zero
+
+ ``Ush``
+ The high part (bits 12 and upwards) of the pc-relative address of a symbol
+ within 4GB of the instruction
+
+ ``Q``
+ A memory address which uses a single base register with no offset
+
+ ``Ump``
+ A memory address suitable for a load/store pair instruction in SI, DI, SF and
+ DF modes
+
+AMD GCN ---:samp:`{config/gcn/constraints.md}`
+
+ ``I``
+ Immediate integer in the range -16 to 64
+
+ ``J``
+ Immediate 16-bit signed integer
+
+ ``Kf``
+ Immediate constant -1
+
+ ``L``
+ Immediate 15-bit unsigned integer
+
+ ``A``
+ Immediate constant that can be inlined in an instruction encoding: integer
+ -16..64, or float 0.0, +/-0.5, +/-1.0, +/-2.0,
+ +/-4.0, 1.0/(2.0\*PI)
+
+ ``B``
+ Immediate 32-bit signed integer that can be attached to an instruction encoding
+
+ ``C``
+ Immediate 32-bit integer in range -16..4294967295 (i.e. 32-bit unsigned
+ integer or :samp:`A` constraint)
+
+ ``DA``
+ Immediate 64-bit constant that can be split into two :samp:`A` constants
+
+ ``DB``
+ Immediate 64-bit constant that can be split into two :samp:`B` constants
+
+ ``U``
+ Any ``unspec``
+
+ ``Y``
+ Any ``symbol_ref`` or ``label_ref``
+
+ ``v``
+ VGPR register
+
+ ``Sg``
+ SGPR register
+
+ ``SD``
+ SGPR registers valid for instruction destinations, including VCC, M0 and EXEC
+
+ ``SS``
+ SGPR registers valid for instruction sources, including VCC, M0, EXEC and SCC
+
+ ``Sm``
+ SGPR registers valid as a source for scalar memory instructions (excludes M0
+ and EXEC)
+
+ ``Sv``
+ SGPR registers valid as a source or destination for vector instructions
+ (excludes EXEC)
+
+ ``ca``
+ All condition registers: SCC, VCCZ, EXECZ
+
+ ``cs``
+ Scalar condition register: SCC
+
+ ``cV``
+ Vector condition register: VCC, VCC_LO, VCC_HI
+
+ ``e``
+ EXEC register (EXEC_LO and EXEC_HI)
+
+ ``RB``
+ Memory operand with address space suitable for ``buffer_*`` instructions
+
+ ``RF``
+ Memory operand with address space suitable for ``flat_*`` instructions
+
+ ``RS``
+ Memory operand with address space suitable for ``s_*`` instructions
+
+ ``RL``
+ Memory operand with address space suitable for ``ds_*`` LDS instructions
+
+ ``RG``
+ Memory operand with address space suitable for ``ds_*`` GDS instructions
+
+ ``RD``
+ Memory operand with address space suitable for any ``ds_*`` instructions
+
+ ``RM``
+ Memory operand with address space suitable for ``global_*`` instructions
+
+ARC ---:samp:`{config/arc/constraints.md}`
+
+ ``q``
+ Registers usable in ARCompact 16-bit instructions: ``r0`` - ``r3``,
+ ``r12`` - ``r15``. This constraint can only match when the :option:`-mq`
+ option is in effect.
+
+ ``e``
+ Registers usable as base-regs of memory addresses in ARCompact 16-bit memory
+ instructions: ``r0`` - ``r3``, ``r12`` - ``r15``, ``sp``.
+ This constraint can only match when the :option:`-mq`
+ option is in effect.
+
+ ``D``
+ ARC FPX (dpfp) 64-bit registers. ``D0``, ``D1``.
+
+ ``I``
+ A signed 12-bit integer constant.
+
+ ``Cal``
+ constant for arithmetic/logical operations. This might be any constant
+ that can be put into a long immediate by the assmbler or linker without
+ involving a PIC relocation.
+
+ ``K``
+ A 3-bit unsigned integer constant.
+
+ ``L``
+ A 6-bit unsigned integer constant.
+
+ ``CnL``
+ One's complement of a 6-bit unsigned integer constant.
+
+ ``CmL``
+ Two's complement of a 6-bit unsigned integer constant.
+
+ ``M``
+ A 5-bit unsigned integer constant.
+
+ ``O``
+ A 7-bit unsigned integer constant.
+
+ ``P``
+ A 8-bit unsigned integer constant.
+
+ ``H``
+ Any const_double value.
+
+ARM family---:samp:`{config/arm/constraints.md}`
+
+ ``h``
+ In Thumb state, the core registers ``r8`` - ``r15``.
+
+ ``k``
+ The stack pointer register.
+
+ ``l``
+ In Thumb State the core registers ``r0`` - ``r7``. In ARM state this
+ is an alias for the ``r`` constraint.
+
+ ``t``
+ VFP floating-point registers ``s0`` - ``s31``. Used for 32 bit values.
+
+ ``w``
+ VFP floating-point registers ``d0`` - ``d31`` and the appropriate
+ subset ``d0`` - ``d15`` based on command line options.
+ Used for 64 bit values only. Not valid for Thumb1.
+
+ ``y``
+ The iWMMX co-processor registers.
+
+ ``z``
+ The iWMMX GR registers.
+
+ ``G``
+ The floating-point constant 0.0
+
+ ``I``
+ Integer that is valid as an immediate operand in a data processing
+ instruction. That is, an integer in the range 0 to 255 rotated by a
+ multiple of 2
+
+ ``J``
+ Integer in the range -4095 to 4095
+
+ ``K``
+ Integer that satisfies constraint :samp:`I` when inverted (ones complement)
+
+ ``L``
+ Integer that satisfies constraint :samp:`I` when negated (twos complement)
+
+ ``M``
+ Integer in the range 0 to 32
+
+ ``Q``
+ A memory reference where the exact address is in a single register
+ (':samp:`m`' is preferable for ``asm`` statements)
+
+ ``R``
+ An item in the constant pool
+
+ ``S``
+ A symbol in the text segment of the current file
+
+ ``Uv``
+ A memory reference suitable for VFP load/store insns (reg+constant offset)
+
+ ``Uy``
+ A memory reference suitable for iWMMXt load/store instructions.
+
+ ``Uq``
+ A memory reference suitable for the ARMv4 ldrsb instruction.
+
+AVR family---:samp:`{config/avr/constraints.md}`
+
+ ``l``
+ Registers from r0 to r15
+
+ ``a``
+ Registers from r16 to r23
+
+ ``d``
+ Registers from r16 to r31
+
+ ``w``
+ Registers from r24 to r31. These registers can be used in :samp:`adiw` command
+
+ ``e``
+ Pointer register (r26--r31)
+
+ ``b``
+ Base pointer register (r28--r31)
+
+ ``q``
+ Stack pointer register (SPH:SPL)
+
+ ``t``
+ Temporary register r0
+
+ ``x``
+ Register pair X (r27:r26)
+
+ ``y``
+ Register pair Y (r29:r28)
+
+ ``z``
+ Register pair Z (r31:r30)
+
+ ``I``
+ Constant greater than -1, less than 64
+
+ ``J``
+ Constant greater than -64, less than 1
+
+ ``K``
+ Constant integer 2
+
+ ``L``
+ Constant integer 0
+
+ ``M``
+ Constant that fits in 8 bits
+
+ ``N``
+ Constant integer -1
+
+ ``O``
+ Constant integer 8, 16, or 24
+
+ ``P``
+ Constant integer 1
+
+ ``G``
+ A floating point constant 0.0
+
+ ``Q``
+ A memory address based on Y or Z pointer with displacement.
+
+Blackfin family---:samp:`{config/bfin/constraints.md}`
+
+ ``a``
+ P register
+
+ ``d``
+ D register
+
+ ``z``
+ A call clobbered P register.
+
+ :samp:`q{n}`
+ A single register. If :samp:`{n}` is in the range 0 to 7, the corresponding D
+ register. If it is ``A``, then the register P0.
+
+ ``D``
+ Even-numbered D register
+
+ ``W``
+ Odd-numbered D register
+
+ ``e``
+ Accumulator register.
+
+ ``A``
+ Even-numbered accumulator register.
+
+ ``B``
+ Odd-numbered accumulator register.
+
+ ``b``
+ I register
+
+ ``v``
+ B register
+
+ ``f``
+ M register
+
+ ``c``
+ Registers used for circular buffering, i.e. I, B, or L registers.
+
+ ``C``
+ The CC register.
+
+ ``t``
+ LT0 or LT1.
+
+ ``k``
+ LC0 or LC1.
+
+ ``u``
+ LB0 or LB1.
+
+ ``x``
+ Any D, P, B, M, I or L register.
+
+ ``y``
+ Additional registers typically used only in prologues and epilogues: RETS,
+ RETN, RETI, RETX, RETE, ASTAT, SEQSTAT and USP.
+
+ ``w``
+ Any register except accumulators or CC.
+
+ ``Ksh``
+ Signed 16 bit integer (in the range -32768 to 32767)
+
+ ``Kuh``
+ Unsigned 16 bit integer (in the range 0 to 65535)
+
+ ``Ks7``
+ Signed 7 bit integer (in the range -64 to 63)
+
+ ``Ku7``
+ Unsigned 7 bit integer (in the range 0 to 127)
+
+ ``Ku5``
+ Unsigned 5 bit integer (in the range 0 to 31)
+
+ ``Ks4``
+ Signed 4 bit integer (in the range -8 to 7)
+
+ ``Ks3``
+ Signed 3 bit integer (in the range -3 to 4)
+
+ ``Ku3``
+ Unsigned 3 bit integer (in the range 0 to 7)
+
+ :samp:`P{n}`
+ Constant :samp:`{n}`, where :samp:`{n}` is a single-digit constant in the range 0 to 4.
+
+ ``PA``
+ An integer equal to one of the MACFLAG_XXX constants that is suitable for
+ use with either accumulator.
+
+ ``PB``
+ An integer equal to one of the MACFLAG_XXX constants that is suitable for
+ use only with accumulator A1.
+
+ ``M1``
+ Constant 255.
+
+ ``M2``
+ Constant 65535.
+
+ ``J``
+ An integer constant with exactly a single bit set.
+
+ ``L``
+ An integer constant with all bits set except exactly one.
+
+ ``H``
+
+ ``Q``
+ Any SYMBOL_REF.
+
+CR16 Architecture---:samp:`{config/cr16/cr16.h}`
+
+ ``b``
+ Registers from r0 to r14 (registers without stack pointer)
+
+ ``t``
+ Register from r0 to r11 (all 16-bit registers)
+
+ ``p``
+ Register from r12 to r15 (all 32-bit registers)
+
+ ``I``
+ Signed constant that fits in 4 bits
+
+ ``J``
+ Signed constant that fits in 5 bits
+
+ ``K``
+ Signed constant that fits in 6 bits
+
+ ``L``
+ Unsigned constant that fits in 4 bits
+
+ ``M``
+ Signed constant that fits in 32 bits
+
+ ``N``
+ Check for 64 bits wide constants for add/sub instructions
+
+ ``G``
+ Floating point constant that is legal for store immediate
+
+C-SKY---:samp:`{config/csky/constraints.md}`
+
+ ``a``
+ The mini registers r0 - r7.
+
+ ``b``
+ The low registers r0 - r15.
+
+ ``c``
+ C register.
+
+ ``y``
+ HI and LO registers.
+
+ ``l``
+ LO register.
+
+ ``h``
+ HI register.
+
+ ``v``
+ Vector registers.
+
+ ``z``
+ Stack pointer register (SP).
+
+ ``Q``
+ A memory address which uses a base register with a short offset
+ or with a index register with its scale.
+
+ ``W``
+ A memory address which uses a base register with a index register
+ with its scale.
+
+ .. only:: gccint
+
+ The C-SKY back end supports a large set of additional constraints
+ that are only useful for instruction selection or splitting rather
+ than inline asm, such as constraints representing constant integer
+ ranges accepted by particular instruction encodings.
+ Refer to the source code for details.
+
+Epiphany---:samp:`{config/epiphany/constraints.md}`
+
+ ``U16``
+ An unsigned 16-bit constant.
+
+ ``K``
+ An unsigned 5-bit constant.
+
+ ``L``
+ A signed 11-bit constant.
+
+ ``Cm1``
+ A signed 11-bit constant added to -1.
+ Can only match when the :option:`-m1reg-`:samp:`{reg}` option is active.
+
+ ``Cl1``
+ Left-shift of -1, i.e., a bit mask with a block of leading ones, the rest
+ being a block of trailing zeroes.
+ Can only match when the :option:`-m1reg-`:samp:`{reg}` option is active.
+
+ ``Cr1``
+ Right-shift of -1, i.e., a bit mask with a trailing block of ones, the
+ rest being zeroes. Or to put it another way, one less than a power of two.
+ Can only match when the :option:`-m1reg-`:samp:`{reg}` option is active.
+
+ ``Cal``
+ Constant for arithmetic/logical operations.
+ This is like ``i``, except that for position independent code,
+ no symbols / expressions needing relocations are allowed.
+
+ ``Csy``
+ Symbolic constant for call/jump instruction.
+
+ ``Rcs``
+ The register class usable in short insns. This is a register class
+ constraint, and can thus drive register allocation.
+ This constraint won't match unless :option:`-mprefer-short-insn-regs` is
+ in effect.
+
+ ``Rsc``
+ The the register class of registers that can be used to hold a
+ sibcall call address. I.e., a caller-saved register.
+
+ ``Rct``
+ Core control register class.
+
+ ``Rgs``
+ The register group usable in short insns.
+ This constraint does not use a register class, so that it only
+ passively matches suitable registers, and doesn't drive register allocation.
+
+ .. only:: gccint
+
+ ``Car``
+ Constant suitable for the addsi3_r pattern. This is a valid offset
+ For byte, halfword, or word addressing.
+
+ ``Rra``
+ Matches the return address if it can be replaced with the link register.
+
+ ``Rcc``
+ Matches the integer condition code register.
+
+ ``Sra``
+ Matches the return address if it is in a stack slot.
+
+ ``Cfm``
+ Matches control register values to switch fp mode, which are encapsulated in
+ ``UNSPEC_FP_MODE``.
+
+FRV---:samp:`{config/frv/frv.h}`
+
+ ``a``
+ Register in the class ``ACC_REGS`` ( ``acc0`` to ``acc7`` ).
+
+ ``b``
+ Register in the class ``EVEN_ACC_REGS`` ( ``acc0`` to ``acc7`` ).
+
+ ``c``
+ Register in the class ``CC_REGS`` ( ``fcc0`` to ``fcc3`` and
+ ``icc0`` to ``icc3`` ).
+
+ ``d``
+ Register in the class ``GPR_REGS`` ( ``gr0`` to ``gr63`` ).
+
+ ``e``
+ Register in the class ``EVEN_REGS`` ( ``gr0`` to ``gr63`` ).
+ Odd registers are excluded not in the class but through the use of a machine
+ mode larger than 4 bytes.
+
+ ``f``
+ Register in the class ``FPR_REGS`` ( ``fr0`` to ``fr63`` ).
+
+ ``h``
+ Register in the class ``FEVEN_REGS`` ( ``fr0`` to ``fr63`` ).
+ Odd registers are excluded not in the class but through the use of a machine
+ mode larger than 4 bytes.
+
+ ``l``
+ Register in the class ``LR_REG`` (the ``lr`` register).
+
+ ``q``
+ Register in the class ``QUAD_REGS`` ( ``gr2`` to ``gr63`` ).
+ Register numbers not divisible by 4 are excluded not in the class but through
+ the use of a machine mode larger than 8 bytes.
+
+ ``t``
+ Register in the class ``ICC_REGS`` ( ``icc0`` to ``icc3`` ).
+
+ ``u``
+ Register in the class ``FCC_REGS`` ( ``fcc0`` to ``fcc3`` ).
+
+ ``v``
+ Register in the class ``ICR_REGS`` ( ``cc4`` to ``cc7`` ).
+
+ ``w``
+ Register in the class ``FCR_REGS`` ( ``cc0`` to ``cc3`` ).
+
+ ``x``
+ Register in the class ``QUAD_FPR_REGS`` ( ``fr0`` to ``fr63`` ).
+ Register numbers not divisible by 4 are excluded not in the class but through
+ the use of a machine mode larger than 8 bytes.
+
+ ``z``
+ Register in the class ``SPR_REGS`` ( ``lcr`` and ``lr`` ).
+
+ ``A``
+ Register in the class ``QUAD_ACC_REGS`` ( ``acc0`` to ``acc7`` ).
+
+ ``B``
+ Register in the class ``ACCG_REGS`` ( ``accg0`` to ``accg7`` ).
+
+ ``C``
+ Register in the class ``CR_REGS`` ( ``cc0`` to ``cc7`` ).
+
+ ``G``
+ Floating point constant zero
+
+ ``I``
+ 6-bit signed integer constant
+
+ ``J``
+ 10-bit signed integer constant
+
+ ``L``
+ 16-bit signed integer constant
+
+ ``M``
+ 16-bit unsigned integer constant
+
+ ``N``
+ 12-bit signed integer constant that is negative---i.e. in the
+ range of -2048 to -1
+
+ ``O``
+ Constant zero
+
+ ``P``
+ 12-bit signed integer constant that is greater than zero---i.e. in the
+ range of 1 to 2047.
+
+FT32---:samp:`{config/ft32/constraints.md}`
+
+ ``A``
+ An absolute address
+
+ ``B``
+ An offset address
+
+ ``W``
+ A register indirect memory operand
+
+ ``e``
+ An offset address.
+
+ ``f``
+ An offset address.
+
+ ``O``
+ The constant zero or one
+
+ ``I``
+ A 16-bit signed constant (-32768 ... 32767)
+
+ ``w``
+ A bitfield mask suitable for bext or bins
+
+ ``x``
+ An inverted bitfield mask suitable for bext or bins
+
+ ``L``
+ A 16-bit unsigned constant, multiple of 4 (0 ... 65532)
+
+ ``S``
+ A 20-bit signed constant (-524288 ... 524287)
+
+ ``b``
+ A constant for a bitfield width (1 ... 16)
+
+ ``KA``
+ A 10-bit signed constant (-512 ... 511)
+
+Hewlett-Packard PA-RISC---:samp:`{config/pa/pa.h}`
+
+ ``a``
+ General register 1
+
+ ``f``
+ Floating point register
+
+ ``q``
+ Shift amount register
+
+ ``x``
+ Floating point register (deprecated)
+
+ ``y``
+ Upper floating point register (32-bit), floating point register (64-bit)
+
+ ``Z``
+ Any register
+
+ ``I``
+ Signed 11-bit integer constant
+
+ ``J``
+ Signed 14-bit integer constant
+
+ ``K``
+ Integer constant that can be deposited with a ``zdepi`` instruction
+
+ ``L``
+ Signed 5-bit integer constant
+
+ ``M``
+ Integer constant 0
+
+ ``N``
+ Integer constant that can be loaded with a ``ldil`` instruction
+
+ ``O``
+ Integer constant whose value plus one is a power of 2
+
+ ``P``
+ Integer constant that can be used for ``and`` operations in ``depi``
+ and ``extru`` instructions
+
+ ``S``
+ Integer constant 31
+
+ ``U``
+ Integer constant 63
+
+ ``G``
+ Floating-point constant 0.0
+
+ ``A``
+ A ``lo_sum`` data-linkage-table memory operand
+
+ ``Q``
+ A memory operand that can be used as the destination operand of an
+ integer store instruction
+
+ ``R``
+ A scaled or unscaled indexed memory operand
+
+ ``T``
+ A memory operand for floating-point loads and stores
+
+ ``W``
+ A register indirect memory operand
+
+Intel IA-64---:samp:`{config/ia64/ia64.h}`
+
+ ``a``
+ General register ``r0`` to ``r3`` for ``addl`` instruction
+
+ ``b``
+ Branch register
+
+ ``c``
+ Predicate register (:samp:`c` as in 'conditional')
+
+ ``d``
+ Application register residing in M-unit
+
+ ``e``
+ Application register residing in I-unit
+
+ ``f``
+ Floating-point register
+
+ ``m``
+ Memory operand. If used together with :samp:`<` or :samp:`>`,
+ the operand can have postincrement and postdecrement which
+ require printing with :samp:`%Pn` on IA-64.
+
+ ``G``
+ Floating-point constant 0.0 or 1.0
+
+ ``I``
+ 14-bit signed integer constant
+
+ ``J``
+ 22-bit signed integer constant
+
+ ``K``
+ 8-bit signed integer constant for logical instructions
+
+ ``L``
+ 8-bit adjusted signed integer constant for compare pseudo-ops
+
+ ``M``
+ 6-bit unsigned integer constant for shift counts
+
+ ``N``
+ 9-bit signed integer constant for load and store postincrements
+
+ ``O``
+ The constant zero
+
+ ``P``
+ 0 or -1 for ``dep`` instruction
+
+ ``Q``
+ Non-volatile memory for floating-point loads and stores
+
+ ``R``
+ Integer constant in the range 1 to 4 for ``shladd`` instruction
+
+ ``S``
+ Memory operand except postincrement and postdecrement. This is
+ now roughly the same as :samp:`m` when not used together with :samp:`<`
+ or :samp:`>`.
+
+M32C---:samp:`{config/m32c/m32c.c}`
+
+ ``Rsp`` ``Rfb`` ``Rsb``
+ :samp:`$sp`, :samp:`$fb`, :samp:`$sb`.
+
+ ``Rcr``
+ Any control register, when they're 16 bits wide (nothing if control
+ registers are 24 bits wide)
+
+ ``Rcl``
+ Any control register, when they're 24 bits wide.
+
+ ``R0w`` ``R1w`` ``R2w`` ``R3w``
+ $r0, $r1, $r2, $r3.
+
+ ``R02``
+ $r0 or $r2, or $r2r0 for 32 bit values.
+
+ ``R13``
+ $r1 or $r3, or $r3r1 for 32 bit values.
+
+ ``Rdi``
+ A register that can hold a 64 bit value.
+
+ ``Rhl``
+ $r0 or $r1 (registers with addressable high/low bytes)
+
+ ``R23``
+ $r2 or $r3
+
+ ``Raa``
+ Address registers
+
+ ``Raw``
+ Address registers when they're 16 bits wide.
+
+ ``Ral``
+ Address registers when they're 24 bits wide.
+
+ ``Rqi``
+ Registers that can hold QI values.
+
+ ``Rad``
+ Registers that can be used with displacements ($a0, $a1, $sb).
+
+ ``Rsi``
+ Registers that can hold 32 bit values.
+
+ ``Rhi``
+ Registers that can hold 16 bit values.
+
+ ``Rhc``
+ Registers chat can hold 16 bit values, including all control
+ registers.
+
+ ``Rra``
+ $r0 through R1, plus $a0 and $a1.
+
+ ``Rfl``
+ The flags register.
+
+ ``Rmm``
+ The memory-based pseudo-registers $mem0 through $mem15.
+
+ ``Rpi``
+ Registers that can hold pointers (16 bit registers for r8c, m16c; 24
+ bit registers for m32cm, m32c).
+
+ ``Rpa``
+ Matches multiple registers in a PARALLEL to form a larger register.
+ Used to match function return values.
+
+ ``Is3``
+ -8 ... 7
+
+ ``IS1``
+ -128 ... 127
+
+ ``IS2``
+ -32768 ... 32767
+
+ ``IU2``
+ 0 ... 65535
+
+ ``In4``
+ -8 ... -1 or 1 ... 8
+
+ ``In5``
+ -16 ... -1 or 1 ... 16
+
+ ``In6``
+ -32 ... -1 or 1 ... 32
+
+ ``IM2``
+ -65536 ... -1
+
+ ``Ilb``
+ An 8 bit value with exactly one bit set.
+
+ ``Ilw``
+ A 16 bit value with exactly one bit set.
+
+ ``Sd``
+ The common src/dest memory addressing modes.
+
+ ``Sa``
+ Memory addressed using $a0 or $a1.
+
+ ``Si``
+ Memory addressed with immediate addresses.
+
+ ``Ss``
+ Memory addressed using the stack pointer ($sp).
+
+ ``Sf``
+ Memory addressed using the frame base register ($fb).
+
+ ``Ss``
+ Memory addressed using the small base register ($sb).
+
+ ``S1``
+ $r1h
+
+MicroBlaze---:samp:`{config/microblaze/constraints.md}`
+
+ ``d``
+ A general register ( ``r0`` to ``r31`` ).
+
+ ``z``
+ A status register ( ``rmsr``, ``$fcc1`` to ``$fcc7`` ).
+
+MIPS---:samp:`{config/mips/constraints.md}`
+
+ ``d``
+ A general-purpose register. This is equivalent to ``r`` unless
+ generating MIPS16 code, in which case the MIPS16 register set is used.
+
+ ``f``
+ A floating-point register (if available).
+
+ ``h``
+ Formerly the ``hi`` register. This constraint is no longer supported.
+
+ ``l``
+ The ``lo`` register. Use this register to store values that are
+ no bigger than a word.
+
+ ``x``
+ The concatenated ``hi`` and ``lo`` registers. Use this register
+ to store doubleword values.
+
+ ``c``
+ A register suitable for use in an indirect jump. This will always be
+ ``$25`` for :option:`-mabicalls`.
+
+ ``v``
+ Register ``$3``. Do not use this constraint in new code;
+ it is retained only for compatibility with glibc.
+
+ ``y``
+ Equivalent to ``r`` ; retained for backwards compatibility.
+
+ ``z``
+ A floating-point condition code register.
+
+ ``I``
+ A signed 16-bit constant (for arithmetic instructions).
+
+ ``J``
+ Integer zero.
+
+ ``K``
+ An unsigned 16-bit constant (for logic instructions).
+
+ ``L``
+ A signed 32-bit constant in which the lower 16 bits are zero.
+ Such constants can be loaded using ``lui``.
+
+ ``M``
+ A constant that cannot be loaded using ``lui``, ``addiu``
+ or ``ori``.
+
+ ``N``
+ A constant in the range -65535 to -1 (inclusive).
+
+ ``O``
+ A signed 15-bit constant.
+
+ ``P``
+ A constant in the range 1 to 65535 (inclusive).
+
+ ``G``
+ Floating-point zero.
+
+ ``R``
+ An address that can be used in a non-macro load or store.
+
+ ``ZC``
+ A memory operand whose address is formed by a base register and offset
+ that is suitable for use in instructions with the same addressing mode
+ as ``ll`` and ``sc``.
+
+ ``ZD``
+ An address suitable for a ``prefetch`` instruction, or for any other
+ instruction with the same addressing mode as ``prefetch``.
+
+Motorola 680x0---:samp:`{config/m68k/constraints.md}`
+
+ ``a``
+ Address register
+
+ ``d``
+ Data register
+
+ ``f``
+ 68881 floating-point register, if available
+
+ ``I``
+ Integer in the range 1 to 8
+
+ ``J``
+ 16-bit signed number
+
+ ``K``
+ Signed number whose magnitude is greater than 0x80
+
+ ``L``
+ Integer in the range -8 to -1
+
+ ``M``
+ Signed number whose magnitude is greater than 0x100
+
+ ``N``
+ Range 24 to 31, rotatert:SI 8 to 1 expressed as rotate
+
+ ``O``
+ 16 (for rotate using swap)
+
+ ``P``
+ Range 8 to 15, rotatert:HI 8 to 1 expressed as rotate
+
+ ``R``
+ Numbers that mov3q can handle
+
+ ``G``
+ Floating point constant that is not a 68881 constant
+
+ ``S``
+ Operands that satisfy 'm' when -mpcrel is in effect
+
+ ``T``
+ Operands that satisfy 's' when -mpcrel is not in effect
+
+ ``Q``
+ Address register indirect addressing mode
+
+ ``U``
+ Register offset addressing
+
+ ``W``
+ const_call_operand
+
+ ``Cs``
+ symbol_ref or const
+
+ ``Ci``
+ const_int
+
+ ``C0``
+ const_int 0
+
+ ``Cj``
+ Range of signed numbers that don't fit in 16 bits
+
+ ``Cmvq``
+ Integers valid for mvq
+
+ ``Capsw``
+ Integers valid for a moveq followed by a swap
+
+ ``Cmvz``
+ Integers valid for mvz
+
+ ``Cmvs``
+ Integers valid for mvs
+
+ ``Ap``
+ push_operand
+
+ ``Ac``
+ Non-register operands allowed in clr
+
+Moxie---:samp:`{config/moxie/constraints.md}`
+
+ ``A``
+ An absolute address
+
+ ``B``
+ An offset address
+
+ ``W``
+ A register indirect memory operand
+
+ ``I``
+ A constant in the range of 0 to 255.
+
+ ``N``
+ A constant in the range of 0 to -255.
+
+:samp:`MSP430--{config/msp430/constraints.md}`
+
+ ``R12``
+ Register R12.
+
+ ``R13``
+ Register R13.
+
+ ``K``
+ Integer constant 1.
+
+ ``L``
+ Integer constant -1^20..1^19.
+
+ ``M``
+ Integer constant 1-4.
+
+ ``Ya``
+ Memory references which do not require an extended MOVX instruction.
+
+ ``Yl``
+ Memory reference, labels only.
+
+ ``Ys``
+ Memory reference, stack only.
+
+NDS32---:samp:`{config/nds32/constraints.md}`
+
+ ``w``
+ LOW register class $r0 to $r7 constraint for V3/V3M ISA.
+
+ ``l``
+ LOW register class $r0 to $r7.
+
+ ``d``
+ MIDDLE register class $r0 to $r11, $r16 to $r19.
+
+ ``h``
+ HIGH register class $r12 to $r14, $r20 to $r31.
+
+ ``t``
+ Temporary assist register $ta (i.e. $r15).
+
+ ``k``
+ Stack register $sp.
+
+ ``Iu03``
+ Unsigned immediate 3-bit value.
+
+ ``In03``
+ Negative immediate 3-bit value in the range of -7--0.
+
+ ``Iu04``
+ Unsigned immediate 4-bit value.
+
+ ``Is05``
+ Signed immediate 5-bit value.
+
+ ``Iu05``
+ Unsigned immediate 5-bit value.
+
+ ``In05``
+ Negative immediate 5-bit value in the range of -31--0.
+
+ ``Ip05``
+ Unsigned immediate 5-bit value for movpi45 instruction with range 16--47.
+
+ ``Iu06``
+ Unsigned immediate 6-bit value constraint for addri36.sp instruction.
+
+ ``Iu08``
+ Unsigned immediate 8-bit value.
+
+ ``Iu09``
+ Unsigned immediate 9-bit value.
+
+ ``Is10``
+ Signed immediate 10-bit value.
+
+ ``Is11``
+ Signed immediate 11-bit value.
+
+ ``Is15``
+ Signed immediate 15-bit value.
+
+ ``Iu15``
+ Unsigned immediate 15-bit value.
+
+ ``Ic15``
+ A constant which is not in the range of imm15u but ok for bclr instruction.
+
+ ``Ie15``
+ A constant which is not in the range of imm15u but ok for bset instruction.
+
+ ``It15``
+ A constant which is not in the range of imm15u but ok for btgl instruction.
+
+ ``Ii15``
+ A constant whose compliment value is in the range of imm15u
+ and ok for bitci instruction.
+
+ ``Is16``
+ Signed immediate 16-bit value.
+
+ ``Is17``
+ Signed immediate 17-bit value.
+
+ ``Is19``
+ Signed immediate 19-bit value.
+
+ ``Is20``
+ Signed immediate 20-bit value.
+
+ ``Ihig``
+ The immediate value that can be simply set high 20-bit.
+
+ ``Izeb``
+ The immediate value 0xff.
+
+ ``Izeh``
+ The immediate value 0xffff.
+
+ ``Ixls``
+ The immediate value 0x01.
+
+ ``Ix11``
+ The immediate value 0x7ff.
+
+ ``Ibms``
+ The immediate value with power of 2.
+
+ ``Ifex``
+ The immediate value with power of 2 minus 1.
+
+ ``U33``
+ Memory constraint for 333 format.
+
+ ``U45``
+ Memory constraint for 45 format.
+
+ ``U37``
+ Memory constraint for 37 format.
+
+Nios II family---:samp:`{config/nios2/constraints.md}`
+
+ ``I``
+ Integer that is valid as an immediate operand in an
+ instruction taking a signed 16-bit number. Range
+ -32768 to 32767.
+
+ ``J``
+ Integer that is valid as an immediate operand in an
+ instruction taking an unsigned 16-bit number. Range
+ 0 to 65535.
+
+ ``K``
+ Integer that is valid as an immediate operand in an
+ instruction taking only the upper 16-bits of a
+ 32-bit number. Range 32-bit numbers with the lower
+ 16-bits being 0.
+
+ ``L``
+ Integer that is valid as an immediate operand for a
+ shift instruction. Range 0 to 31.
+
+ ``M``
+ Integer that is valid as an immediate operand for
+ only the value 0. Can be used in conjunction with
+ the format modifier ``z`` to use ``r0``
+ instead of ``0`` in the assembly output.
+
+ ``N``
+ Integer that is valid as an immediate operand for
+ a custom instruction opcode. Range 0 to 255.
+
+ ``P``
+ An immediate operand for R2 andchi/andci instructions.
+
+ ``S``
+ Matches immediates which are addresses in the small
+ data section and therefore can be added to ``gp``
+ as a 16-bit immediate to re-create their 32-bit value.
+
+ ``U``
+ Matches constants suitable as an operand for the rdprs and
+ cache instructions.
+
+ ``v``
+ A memory operand suitable for Nios II R2 load/store
+ exclusive instructions.
+
+ ``w``
+ A memory operand suitable for load/store IO and cache
+ instructions.
+
+ .. only:: gccint
+
+ ``T``
+ A ``const`` wrapped ``UNSPEC`` expression,
+ representing a supported PIC or TLS relocation.
+
+OpenRISC---:samp:`{config/or1k/constraints.md}`
+
+ ``I``
+ Integer that is valid as an immediate operand in an
+ instruction taking a signed 16-bit number. Range
+ -32768 to 32767.
+
+ ``K``
+ Integer that is valid as an immediate operand in an
+ instruction taking an unsigned 16-bit number. Range
+ 0 to 65535.
+
+ ``M``
+ Signed 16-bit constant shifted left 16 bits. (Used with ``l.movhi`` )
+
+ ``O``
+ Zero
+
+ .. only:: gccint
+
+ ``c``
+ Register usable for sibcalls.
+
+PDP-11---:samp:`{config/pdp11/constraints.md}`
+
+ ``a``
+ Floating point registers AC0 through AC3. These can be loaded from/to
+ memory with a single instruction.
+
+ ``d``
+ Odd numbered general registers (R1, R3, R5). These are used for
+ 16-bit multiply operations.
+
+ ``D``
+ A memory reference that is encoded within the opcode, but not
+ auto-increment or auto-decrement.
+
+ ``f``
+ Any of the floating point registers (AC0 through AC5).
+
+ ``G``
+ Floating point constant 0.
+
+ ``h``
+ Floating point registers AC4 and AC5. These cannot be loaded from/to
+ memory with a single instruction.
+
+ ``I``
+ An integer constant that fits in 16 bits.
+
+ ``J``
+ An integer constant whose low order 16 bits are zero.
+
+ ``K``
+ An integer constant that does not meet the constraints for codes
+ :samp:`I` or :samp:`J`.
+
+ ``L``
+ The integer constant 1.
+
+ ``M``
+ The integer constant -1.
+
+ ``N``
+ The integer constant 0.
+
+ ``O``
+ Integer constants 0 through 3; shifts by these
+ amounts are handled as multiple single-bit shifts rather than a single
+ variable-length shift.
+
+ ``Q``
+ A memory reference which requires an additional word (address or
+ offset) after the opcode.
+
+ ``R``
+ A memory reference that is encoded within the opcode.
+
+PowerPC and IBM RS6000---:samp:`{config/rs6000/constraints.md}`
+
+ ``r``
+ A general purpose register (GPR), ``r0``... ``r31``.
+
+ ``b``
+ A base register. Like ``r``, but ``r0`` is not allowed, so
+ ``r1``... ``r31``.
+
+ ``f``
+ A floating point register (FPR), ``f0``... ``f31``.
+
+ ``d``
+ A floating point register. This is the same as ``f`` nowadays;
+ historically ``f`` was for single-precision and ``d`` was for
+ double-precision floating point.
+
+ ``v``
+ An Altivec vector register (VR), ``v0``... ``v31``.
+
+ ``wa``
+ A VSX register (VSR), ``vs0``... ``vs63``. This is either an
+ FPR ( ``vs0``... ``vs31`` are ``f0``... ``f31`` ) or a VR
+ ( ``vs32``... ``vs63`` are ``v0``... ``v31`` ).
+
+ When using ``wa``, you should use the ``%x`` output modifier, so that
+ the correct register number is printed. For example:
+
+ .. code-block:: c++
+
+ asm ("xvadddp %x0,%x1,%x2"
+ : "=wa" (v1)
+ : "wa" (v2), "wa" (v3));
+
+ You should not use ``%x`` for ``v`` operands:
+
+ .. code-block:: c++
+
+ asm ("xsaddqp %0,%1,%2"
+ : "=v" (v1)
+ : "v" (v2), "v" (v3));
+
+
+ .. only:: gccint
+
+ ``h``
+ A special register ( ``vrsave``, ``ctr``, or ``lr`` ).
+
+ ``c``
+ The count register, ``ctr``.
+
+ ``l``
+ The link register, ``lr``.
+
+ ``x``
+ Condition register field 0, ``cr0``.
+
+ ``y``
+ Any condition register field, ``cr0``... ``cr7``.
+
+ .. only:: gccint
+
+ ``z``
+ The carry bit, ``XER[CA]``.
+
+ ``we``
+ Like ``wa``, if :option:`-mpower9-vector` and :option:`-m64` are used;
+ otherwise, ``NO_REGS``.
+
+ ``wn``
+ No register ( ``NO_REGS`` ).
+
+ ``wr``
+ Like ``r``, if :option:`-mpowerpc64` is used; otherwise, ``NO_REGS``.
+
+ ``wx``
+ Like ``d``, if :option:`-mpowerpc-gfxopt` is used; otherwise, ``NO_REGS``.
+
+ ``wA``
+ Like ``b``, if :option:`-mpowerpc64` is used; otherwise, ``NO_REGS``.
+
+ ``wB``
+ Signed 5-bit constant integer that can be loaded into an Altivec register.
+
+ ``wD``
+ Int constant that is the element number of the 64-bit scalar in a vector.
+
+ ``wE``
+ Vector constant that can be loaded with the XXSPLTIB instruction.
+
+ ``wF``
+ Memory operand suitable for power8 GPR load fusion.
+
+ ``wL``
+ Int constant that is the element number mfvsrld accesses in a vector.
+
+ ``wM``
+ Match vector constant with all 1's if the XXLORC instruction is available.
+
+ ``wO``
+ Memory operand suitable for the ISA 3.0 vector d-form instructions.
+
+ ``wQ``
+ Memory operand suitable for the load/store quad instructions.
+
+ ``wS``
+ Vector constant that can be loaded with XXSPLTIB & sign extension.
+
+ ``wY``
+ A memory operand for a DS-form instruction.
+
+ ``wZ``
+ An indexed or indirect memory operand, ignoring the bottom 4 bits.
+
+ ``I``
+ A signed 16-bit constant.
+
+ ``J``
+ An unsigned 16-bit constant shifted left 16 bits (use ``L`` instead
+ for ``SImode`` constants).
+
+ ``K``
+ An unsigned 16-bit constant.
+
+ ``L``
+ A signed 16-bit constant shifted left 16 bits.
+
+ .. only:: gccint
+
+ ``M``
+ An integer constant greater than 31.
+
+ ``N``
+ An exact power of 2.
+
+ ``O``
+ The integer constant zero.
+
+ ``P``
+ A constant whose negation is a signed 16-bit constant.
+
+ ``eI``
+ A signed 34-bit integer constant if prefixed instructions are supported.
+
+ .. only:: gccint
+
+ ``G``
+ A floating point constant that can be loaded into a register with one
+ instruction per word.
+
+ ``H``
+ A floating point constant that can be loaded into a register using
+ three instructions.
+
+ ``m``
+ A memory operand.
+ Normally, ``m`` does not allow addresses that update the base register.
+ If the ``<`` or ``>`` constraint is also used, they are allowed and
+ therefore on PowerPC targets in that case it is only safe
+ to use ``m<>`` in an ``asm`` statement if that ``asm`` statement
+ accesses the operand exactly once. The ``asm`` statement must also
+ use ``%U<opno>`` as a placeholder for the 'update' flag in the
+ corresponding load or store instruction. For example:
+
+ .. code-block:: c++
+
+ asm ("st%U0 %1,%0" : "=m<>" (mem) : "r" (val));
+
+ is correct but:
+
+ .. code-block:: c++
+
+ asm ("st %1,%0" : "=m<>" (mem) : "r" (val));
+
+ is not.
+
+ .. only:: gccint
+
+ ``es``
+ A 'stable' memory operand; that is, one which does not include any
+ automodification of the base register. This used to be useful when
+ ``m`` allowed automodification of the base register, but as those
+ are now only allowed when ``<`` or ``>`` is used, ``es`` is
+ basically the same as ``m`` without ``<`` and ``>``.
+
+ ``Q``
+ A memory operand addressed by just a base register.
+
+ .. only:: gccint
+
+ ``Y``
+ A memory operand for a DQ-form instruction.
+
+ ``Z``
+ A memory operand accessed with indexed or indirect addressing.
+
+ .. only:: gccint
+
+ ``R``
+ An AIX TOC entry.
+
+ ``a``
+ An indexed or indirect address.
+
+ .. only:: gccint
+
+ ``U``
+ A V.4 small data reference.
+
+ ``W``
+ A vector constant that does not require memory.
+
+ ``j``
+ The zero vector constant.
+
+PRU---:samp:`{config/pru/constraints.md}`
+
+ ``I``
+ An unsigned 8-bit integer constant.
+
+ ``J``
+ An unsigned 16-bit integer constant.
+
+ ``L``
+ An unsigned 5-bit integer constant (for shift counts).
+
+ ``T``
+ A text segment (program memory) constant label.
+
+ ``Z``
+ Integer constant zero.
+
+RL78---:samp:`{config/rl78/constraints.md}`
+
+ ``Int3``
+ An integer constant in the range 1 ... 7.
+
+ ``Int8``
+ An integer constant in the range 0 ... 255.
+
+ ``J``
+ An integer constant in the range -255 ... 0
+
+ ``K``
+ The integer constant 1.
+
+ ``L``
+ The integer constant -1.
+
+ ``M``
+ The integer constant 0.
+
+ ``N``
+ The integer constant 2.
+
+ ``O``
+ The integer constant -2.
+
+ ``P``
+ An integer constant in the range 1 ... 15.
+
+ ``Qbi``
+ The built-in compare types--eq, ne, gtu, ltu, geu, and leu.
+
+ ``Qsc``
+ The synthetic compare types--gt, lt, ge, and le.
+
+ ``Wab``
+ A memory reference with an absolute address.
+
+ ``Wbc``
+ A memory reference using ``BC`` as a base register, with an optional offset.
+
+ ``Wca``
+ A memory reference using ``AX``, ``BC``, ``DE``, or ``HL`` for the address, for calls.
+
+ ``Wcv``
+ A memory reference using any 16-bit register pair for the address, for calls.
+
+ ``Wd2``
+ A memory reference using ``DE`` as a base register, with an optional offset.
+
+ ``Wde``
+ A memory reference using ``DE`` as a base register, without any offset.
+
+ ``Wfr``
+ Any memory reference to an address in the far address space.
+
+ ``Wh1``
+ A memory reference using ``HL`` as a base register, with an optional one-byte offset.
+
+ ``Whb``
+ A memory reference using ``HL`` as a base register, with ``B`` or ``C`` as the index register.
+
+ ``Whl``
+ A memory reference using ``HL`` as a base register, without any offset.
+
+ ``Ws1``
+ A memory reference using ``SP`` as a base register, with an optional one-byte offset.
+
+ ``Y``
+ Any memory reference to an address in the near address space.
+
+ ``A``
+ The ``AX`` register.
+
+ ``B``
+ The ``BC`` register.
+
+ ``D``
+ The ``DE`` register.
+
+ ``R``
+ ``A`` through ``L`` registers.
+
+ ``S``
+ The ``SP`` register.
+
+ ``T``
+ The ``HL`` register.
+
+ ``Z08W``
+ The 16-bit ``R8`` register.
+
+ ``Z10W``
+ The 16-bit ``R10`` register.
+
+ ``Zint``
+ The registers reserved for interrupts ( ``R24`` to ``R31`` ).
+
+ ``a``
+ The ``A`` register.
+
+ ``b``
+ The ``B`` register.
+
+ ``c``
+ The ``C`` register.
+
+ ``d``
+ The ``D`` register.
+
+ ``e``
+ The ``E`` register.
+
+ ``h``
+ The ``H`` register.
+
+ ``l``
+ The ``L`` register.
+
+ ``v``
+ The virtual registers.
+
+ ``w``
+ The ``PSW`` register.
+
+ ``x``
+ The ``X`` register.
+
+RISC-V---:samp:`{config/riscv/constraints.md}`
+
+ ``f``
+ A floating-point register (if available).
+
+ ``I``
+ An I-type 12-bit signed immediate.
+
+ ``J``
+ Integer zero.
+
+ ``K``
+ A 5-bit unsigned immediate for CSR access instructions.
+
+ ``A``
+ An address that is held in a general-purpose register.
+
+RX---:samp:`{config/rx/constraints.md}`
+
+ ``Q``
+ An address which does not involve register indirect addressing or
+ pre/post increment/decrement addressing.
+
+ ``Symbol``
+ A symbol reference.
+
+ ``Int08``
+ A constant in the range -256 to 255, inclusive.
+
+ ``Sint08``
+ A constant in the range -128 to 127, inclusive.
+
+ ``Sint16``
+ A constant in the range -32768 to 32767, inclusive.
+
+ ``Sint24``
+ A constant in the range -8388608 to 8388607, inclusive.
+
+ ``Uint04``
+ A constant in the range 0 to 15, inclusive.
+
+S/390 and zSeries---:samp:`{config/s390/s390.h}`
+
+ ``a``
+ Address register (general purpose register except r0)
+
+ ``c``
+ Condition code register
+
+ ``d``
+ Data register (arbitrary general purpose register)
+
+ ``f``
+ Floating-point register
+
+ ``I``
+ Unsigned 8-bit constant (0--255)
+
+ ``J``
+ Unsigned 12-bit constant (0--4095)
+
+ ``K``
+ Signed 16-bit constant (-32768--32767)
+
+ ``L``
+ Value appropriate as displacement.
+
+ ``(0..4095)``
+ for short displacement
+
+ ``(-524288..524287)``
+ for long displacement
+
+ ``M``
+ Constant integer with a value of 0x7fffffff.
+
+ ``N``
+ Multiple letter constraint followed by 4 parameter letters.
+
+ ``0..9:``
+ number of the part counting from most to least significant
+
+ ``H,Q:``
+ mode of the part
+
+ ``D,S,H:``
+ mode of the containing operand
+
+ ``0,F:``
+ value of the other parts (F---all bits set)
+
+ The constraint matches if the specified part of a constant
+ has a value different from its other parts.
+
+ ``Q``
+ Memory reference without index register and with short displacement.
+
+ ``R``
+ Memory reference with index register and short displacement.
+
+ ``S``
+ Memory reference without index register but with long displacement.
+
+ ``T``
+ Memory reference with index register and long displacement.
+
+ ``U``
+ Pointer with short displacement.
+
+ ``W``
+ Pointer with long displacement.
+
+ ``Y``
+ Shift count operand.
+
+SPARC---:samp:`{config/sparc/sparc.h}`
+
+ ``f``
+ Floating-point register on the SPARC-V8 architecture and
+ lower floating-point register on the SPARC-V9 architecture.
+
+ ``e``
+ Floating-point register. It is equivalent to :samp:`f` on the
+ SPARC-V8 architecture and contains both lower and upper
+ floating-point registers on the SPARC-V9 architecture.
+
+ ``c``
+ Floating-point condition code register.
+
+ ``d``
+ Lower floating-point register. It is only valid on the SPARC-V9
+ architecture when the Visual Instruction Set is available.
+
+ ``b``
+ Floating-point register. It is only valid on the SPARC-V9 architecture
+ when the Visual Instruction Set is available.
+
+ ``h``
+ 64-bit global or out register for the SPARC-V8+ architecture.
+
+ ``C``
+ The constant all-ones, for floating-point.
+
+ ``A``
+ Signed 5-bit constant
+
+ ``D``
+ A vector constant
+
+ ``I``
+ Signed 13-bit constant
+
+ ``J``
+ Zero
+
+ ``K``
+ 32-bit constant with the low 12 bits clear (a constant that can be
+ loaded with the ``sethi`` instruction)
+
+ ``L``
+ A constant in the range supported by ``movcc`` instructions (11-bit
+ signed immediate)
+
+ ``M``
+ A constant in the range supported by ``movrcc`` instructions (10-bit
+ signed immediate)
+
+ ``N``
+ Same as :samp:`K`, except that it verifies that bits that are not in the
+ lower 32-bit range are all zero. Must be used instead of :samp:`K` for
+ modes wider than ``SImode``
+
+ ``O``
+ The constant 4096
+
+ ``G``
+ Floating-point zero
+
+ ``H``
+ Signed 13-bit constant, sign-extended to 32 or 64 bits
+
+ ``P``
+ The constant -1
+
+ ``Q``
+ Floating-point constant whose integral representation can
+ be moved into an integer register using a single sethi
+ instruction
+
+ ``R``
+ Floating-point constant whose integral representation can
+ be moved into an integer register using a single mov
+ instruction
+
+ ``S``
+ Floating-point constant whose integral representation can
+ be moved into an integer register using a high/lo_sum
+ instruction sequence
+
+ ``T``
+ Memory address aligned to an 8-byte boundary
+
+ ``U``
+ Even register
+
+ ``W``
+ Memory address for :samp:`e` constraint registers
+
+ ``w``
+ Memory address with only a base register
+
+ ``Y``
+ Vector zero
+
+TI C6X family---:samp:`{config/c6x/constraints.md}`
+
+ ``a``
+ Register file A (A0--A31).
+
+ ``b``
+ Register file B (B0--B31).
+
+ ``A``
+ Predicate registers in register file A (A0--A2 on C64X and
+ higher, A1 and A2 otherwise).
+
+ ``B``
+ Predicate registers in register file B (B0--B2).
+
+ ``C``
+ A call-used register in register file B (B0--B9, B16--B31).
+
+ ``Da``
+ Register file A, excluding predicate registers (A3--A31,
+ plus A0 if not C64X or higher).
+
+ ``Db``
+ Register file B, excluding predicate registers (B3--B31).
+
+ ``Iu4``
+ Integer constant in the range 0 ... 15.
+
+ ``Iu5``
+ Integer constant in the range 0 ... 31.
+
+ ``In5``
+ Integer constant in the range -31 ... 0.
+
+ ``Is5``
+ Integer constant in the range -16 ... 15.
+
+ ``I5x``
+ Integer constant that can be the operand of an ADDA or a SUBA insn.
+
+ ``IuB``
+ Integer constant in the range 0 ... 65535.
+
+ ``IsB``
+ Integer constant in the range -32768 ... 32767.
+
+ ``IsC``
+ Integer constant in the range -2^{20} ... 2^{20} - 1.
+
+ ``Jc``
+ Integer constant that is a valid mask for the clr instruction.
+
+ ``Js``
+ Integer constant that is a valid mask for the set instruction.
+
+ ``Q``
+ Memory location with A base register.
+
+ ``R``
+ Memory location with B base register.
+
+ .. only:: gccint
+
+ ``S0``
+ On C64x+ targets, a GP-relative small data reference.
+
+ ``S1``
+ Any kind of ``SYMBOL_REF``, for use in a call address.
+
+ ``Si``
+ Any kind of immediate operand, unless it matches the S0 constraint.
+
+ ``T``
+ Memory location with B base register, but not using a long offset.
+
+ ``W``
+ A memory operand with an address that cannot be used in an unaligned access.
+
+ ``Z``
+ Register B14 (aka DP).
+
+TILE-Gx---:samp:`{config/tilegx/constraints.md}`
+
+ ``R00`` ``R01`` ``R02`` ``R03`` ``R04`` ``R05`` ``R06`` ``R07`` ``R08`` ``R09`` ``R10``
+ Each of these represents a register constraint for an individual
+ register, from r0 to r10.
+
+ ``I``
+ Signed 8-bit integer constant.
+
+ ``J``
+ Signed 16-bit integer constant.
+
+ ``K``
+ Unsigned 16-bit integer constant.
+
+ ``L``
+ Integer constant that fits in one signed byte when incremented by one
+ (-129 ... 126).
+
+ ``m``
+ Memory operand. If used together with :samp:`<` or :samp:`>`, the
+ operand can have postincrement which requires printing with :samp:`%In`
+ and :samp:`%in` on TILE-Gx. For example:
+
+ .. code-block:: c++
+
+ asm ("st_add %I0,%1,%i0" : "=m<>" (*mem) : "r" (val));
+
+ ``M``
+ A bit mask suitable for the BFINS instruction.
+
+ ``N``
+ Integer constant that is a byte tiled out eight times.
+
+ ``O``
+ The integer zero constant.
+
+ ``P``
+ Integer constant that is a sign-extended byte tiled out as four shorts.
+
+ ``Q``
+ Integer constant that fits in one signed byte when incremented
+ (-129 ... 126), but excluding -1.
+
+ ``S``
+ Integer constant that has all 1 bits consecutive and starting at bit 0.
+
+ ``T``
+ A 16-bit fragment of a got, tls, or pc-relative reference.
+
+ ``U``
+ Memory operand except postincrement. This is roughly the same as
+ :samp:`m` when not used together with :samp:`<` or :samp:`>`.
+
+ ``W``
+ An 8-element vector constant with identical elements.
+
+ ``Y``
+ A 4-element vector constant with identical elements.
+
+ ``Z0``
+ The integer constant 0xffffffff.
+
+ ``Z1``
+ The integer constant 0xffffffff00000000.
+
+TILEPro---:samp:`{config/tilepro/constraints.md}`
+
+ ``R00`` ``R01`` ``R02`` ``R03`` ``R04`` ``R05`` ``R06`` ``R07`` ``R08`` ``R09`` ``R10``
+ Each of these represents a register constraint for an individual
+ register, from r0 to r10.
+
+ ``I``
+ Signed 8-bit integer constant.
+
+ ``J``
+ Signed 16-bit integer constant.
+
+ ``K``
+ Nonzero integer constant with low 16 bits zero.
+
+ ``L``
+ Integer constant that fits in one signed byte when incremented by one
+ (-129 ... 126).
+
+ ``m``
+ Memory operand. If used together with :samp:`<` or :samp:`>`, the
+ operand can have postincrement which requires printing with :samp:`%In`
+ and :samp:`%in` on TILEPro. For example:
+
+ .. code-block:: c++
+
+ asm ("swadd %I0,%1,%i0" : "=m<>" (mem) : "r" (val));
+
+ ``M``
+ A bit mask suitable for the MM instruction.
+
+ ``N``
+ Integer constant that is a byte tiled out four times.
+
+ ``O``
+ The integer zero constant.
+
+ ``P``
+ Integer constant that is a sign-extended byte tiled out as two shorts.
+
+ ``Q``
+ Integer constant that fits in one signed byte when incremented
+ (-129 ... 126), but excluding -1.
+
+ ``T``
+ A symbolic operand, or a 16-bit fragment of a got, tls, or pc-relative
+ reference.
+
+ ``U``
+ Memory operand except postincrement. This is roughly the same as
+ :samp:`m` when not used together with :samp:`<` or :samp:`>`.
+
+ ``W``
+ A 4-element vector constant with identical elements.
+
+ ``Y``
+ A 2-element vector constant with identical elements.
+
+Visium---:samp:`{config/visium/constraints.md}`
+
+ ``b``
+ EAM register ``mdb``
+
+ ``c``
+ EAM register ``mdc``
+
+ ``f``
+ Floating point register
+
+ .. only:: gccint
+
+ ``k``
+ Register for sibcall optimization
+
+ ``l``
+ General register, but not ``r29``, ``r30`` and ``r31``
+
+ ``t``
+ Register ``r1``
+
+ ``u``
+ Register ``r2``
+
+ ``v``
+ Register ``r3``
+
+ ``G``
+ Floating-point constant 0.0
+
+ ``J``
+ Integer constant in the range 0 .. 65535 (16-bit immediate)
+
+ ``K``
+ Integer constant in the range 1 .. 31 (5-bit immediate)
+
+ ``L``
+ Integer constant in the range -65535 .. -1 (16-bit negative immediate)
+
+ ``M``
+ Integer constant -1
+
+ ``O``
+ Integer constant 0
+
+ ``P``
+ Integer constant 32
+
+x86 family---:samp:`{config/i386/constraints.md}`
+
+ ``R``
+ Legacy register---the eight integer registers available on all
+ i386 processors ( ``a``, ``b``, ``c``, ``d``,
+ ``si``, ``di``, ``bp``, ``sp`` ).
+
+ ``q``
+ Any register accessible as ``rl``. In 32-bit mode, ``a``,
+ ``b``, ``c``, and ``d`` ; in 64-bit mode, any integer register.
+
+ ``Q``
+ Any register accessible as ``rh`` : ``a``, ``b``,
+ ``c``, and ``d``.
+
+ .. only:: gccint
+
+ ``l``
+ Any register that can be used as the index in a base+index memory
+ access: that is, any general register except the stack pointer.
+
+ ``a``
+ The ``a`` register.
+
+ ``b``
+ The ``b`` register.
+
+ ``c``
+ The ``c`` register.
+
+ ``d``
+ The ``d`` register.
+
+ ``S``
+ The ``si`` register.
+
+ ``D``
+ The ``di`` register.
+
+ ``A``
+ The ``a`` and ``d`` registers. This class is used for instructions
+ that return double word results in the ``ax:dx`` register pair. Single
+ word values will be allocated either in ``ax`` or ``dx``.
+ For example on i386 the following implements ``rdtsc`` :
+
+ .. code-block:: c++
+
+ unsigned long long rdtsc (void)
+ {
+ unsigned long long tick;
+ __asm__ __volatile__("rdtsc":"=A"(tick));
+ return tick;
+ }
+
+ This is not correct on x86-64 as it would allocate tick in either ``ax``
+ or ``dx``. You have to use the following variant instead:
+
+ .. code-block:: c++
+
+ unsigned long long rdtsc (void)
+ {
+ unsigned int tickl, tickh;
+ __asm__ __volatile__("rdtsc":"=a"(tickl),"=d"(tickh));
+ return ((unsigned long long)tickh << 32)|tickl;
+ }
+
+ ``U``
+ The call-clobbered integer registers.
+
+ ``f``
+ Any 80387 floating-point (stack) register.
+
+ ``t``
+ Top of 80387 floating-point stack ( ``%st(0)`` ).
+
+ ``u``
+ Second from top of 80387 floating-point stack ( ``%st(1)`` ).
+
+ .. only:: gccint
+
+ ``Yk``
+ Any mask register that can be used as a predicate, i.e. ``k1-k7``.
+
+ ``k``
+ Any mask register.
+
+ ``y``
+ Any MMX register.
+
+ ``x``
+ Any SSE register.
+
+ ``v``
+ Any EVEX encodable SSE register ( ``%xmm0-%xmm31`` ).
+
+ .. only:: gccint
+
+ ``w``
+ Any bound register.
+
+ ``Yz``
+ First SSE register ( ``%xmm0`` ).
+
+ .. only:: gccint
+
+ ``Yi``
+ Any SSE register, when SSE2 and inter-unit moves are enabled.
+
+ ``Yj``
+ Any SSE register, when SSE2 and inter-unit moves from vector registers are enabled.
+
+ ``Ym``
+ Any MMX register, when inter-unit moves are enabled.
+
+ ``Yn``
+ Any MMX register, when inter-unit moves from vector registers are enabled.
+
+ ``Yp``
+ Any integer register when ``TARGET_PARTIAL_REG_STALL`` is disabled.
+
+ ``Ya``
+ Any integer register when zero extensions with ``AND`` are disabled.
+
+ ``Yb``
+ Any register that can be used as the GOT base when calling
+
+ ``___tls_get_addr`` : that is, any general register except ``a``
+ and ``sp`` registers, for :option:`-fno-plt` if linker supports it.
+ Otherwise, ``b`` register.
+
+ ``Yf``
+ Any x87 register when 80387 floating-point arithmetic is enabled.
+
+ ``Yr``
+ Lower SSE register when avoiding REX prefix and all SSE registers otherwise.
+
+ ``Yv``
+ For AVX512VL, any EVEX-encodable SSE register ( ``%xmm0-%xmm31`` ),
+ otherwise any SSE register.
+
+ ``Yh``
+ Any EVEX-encodable SSE register, that has number factor of four.
+
+ ``Bf``
+ Flags register operand.
+
+ ``Bg``
+ GOT memory operand.
+
+ ``Bm``
+ Vector memory operand.
+
+ ``Bc``
+ Constant memory operand.
+
+ ``Bn``
+ Memory operand without REX prefix.
+
+ ``Bs``
+ Sibcall memory operand.
+
+ ``Bw``
+ Call memory operand.
+
+ ``Bz``
+ Constant call address operand.
+
+ ``BC``
+ SSE constant -1 operand.
+
+ ``I``
+ Integer constant in the range 0 ... 31, for 32-bit shifts.
+
+ ``J``
+ Integer constant in the range 0 ... 63, for 64-bit shifts.
+
+ ``K``
+ Signed 8-bit integer constant.
+
+ ``L``
+ ``0xFF`` or ``0xFFFF``, for andsi as a zero-extending move.
+
+ ``M``
+ 0, 1, 2, or 3 (shifts for the ``lea`` instruction).
+
+ ``N``
+ Unsigned 8-bit integer constant (for ``in`` and ``out``
+ instructions).
+
+ .. only:: gccint
+
+ ``O``
+ Integer constant in the range 0 ... 127, for 128-bit shifts.
+
+ ``G``
+ Standard 80387 floating point constant.
+
+ ``C``
+ SSE constant zero operand.
+
+ ``e``
+ 32-bit signed integer constant, or a symbolic reference known
+ to fit that range (for immediate operands in sign-extending x86-64
+ instructions).
+
+ ``We``
+ 32-bit signed integer constant, or a symbolic reference known
+ to fit that range (for sign-extending conversion operations that
+ require non- ``VOIDmode`` immediate operands).
+
+ ``Wz``
+ 32-bit unsigned integer constant, or a symbolic reference known
+ to fit that range (for zero-extending conversion operations that
+ require non- ``VOIDmode`` immediate operands).
+
+ ``Wd``
+ 128-bit integer constant where both the high and low 64-bit word
+ satisfy the ``e`` constraint.
+
+ ``Z``
+ 32-bit unsigned integer constant, or a symbolic reference known
+ to fit that range (for immediate operands in zero-extending x86-64
+ instructions).
+
+ ``Tv``
+ VSIB address operand.
+
+ ``Ts``
+ Address operand without segment register.
+
+Xstormy16---:samp:`{config/stormy16/stormy16.h}`
+
+ ``a``
+ Register r0.
+
+ ``b``
+ Register r1.
+
+ ``c``
+ Register r2.
+
+ ``d``
+ Register r8.
+
+ ``e``
+ Registers r0 through r7.
+
+ ``t``
+ Registers r0 and r1.
+
+ ``y``
+ The carry register.
+
+ ``z``
+ Registers r8 and r9.
+
+ ``I``
+ A constant between 0 and 3 inclusive.
+
+ ``J``
+ A constant that has exactly one bit set.
+
+ ``K``
+ A constant that has exactly one bit clear.
+
+ ``L``
+ A constant between 0 and 255 inclusive.
+
+ ``M``
+ A constant between -255 and 0 inclusive.
+
+ ``N``
+ A constant between -3 and 0 inclusive.
+
+ ``O``
+ A constant between 1 and 4 inclusive.
+
+ ``P``
+ A constant between -4 and -1 inclusive.
+
+ ``Q``
+ A memory reference that is a stack push.
+
+ ``R``
+ A memory reference that is a stack pop.
+
+ ``S``
+ A memory reference that refers to a constant address of known value.
+
+ ``T``
+ The register indicated by Rx (not implemented yet).
+
+ ``U``
+ A constant that is not between 2 and 15 inclusive.
+
+ ``Z``
+ The constant 0.
+
+Xtensa---:samp:`{config/xtensa/constraints.md}`
+
+ ``a``
+ General-purpose 32-bit register
+
+ ``b``
+ One-bit boolean register
+
+ ``A``
+ MAC16 40-bit accumulator register
+
+ ``I``
+ Signed 12-bit integer constant, for use in MOVI instructions
+
+ ``J``
+ Signed 8-bit integer constant, for use in ADDI instructions
+
+ ``K``
+ Integer constant valid for BccI instructions
+
+ ``L``
+ Unsigned constant valid for BccUI instructions
\ No newline at end of file
diff --git a/gcc/doc/cpp/character-sets.rst b/gcc/doc/cpp/character-sets.rst
new file mode 100644
index 00000000000..e31934ac79b
--- /dev/null
+++ b/gcc/doc/cpp/character-sets.rst
@@ -0,0 +1,56 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _character-sets:
+
+Character sets
+**************
+
+Source code character set processing in C and related languages is
+rather complicated. The C standard discusses two character sets, but
+there are really at least four.
+
+The files input to CPP might be in any character set at all. CPP's
+very first action, before it even looks for line boundaries, is to
+convert the file into the character set it uses for internal
+processing. That set is what the C standard calls the :dfn:`source`
+character set. It must be isomorphic with ISO 10646, also known as
+Unicode. CPP uses the UTF-8 encoding of Unicode.
+
+The character sets of the input files are specified using the
+:option:`-finput-charset` = option.
+
+All preprocessing work (the subject of the rest of this manual) is
+carried out in the source character set. If you request textual
+output from the preprocessor with the :option:`-E` option, it will be
+in UTF-8.
+
+After preprocessing is complete, string and character constants are
+converted again, into the :dfn:`execution` character set. This
+character set is under control of the user; the default is UTF-8,
+matching the source character set. Wide string and character
+constants have their own character set, which is not called out
+specifically in the standard. Again, it is under control of the user.
+The default is UTF-16 or UTF-32, whichever fits in the target's
+``wchar_t`` type, in the target machine's byte
+order [#f1]_.
+
+Octal and hexadecimal escape sequences do not undergo
+conversion; ``'\x12'`` has the value 0x12 regardless of the currently
+selected execution character set. All other escapes are replaced by
+the character in the source character set that they represent, then
+converted to the execution character set, just like unescaped
+characters.
+
+In identifiers, characters outside the ASCII range can be specified
+with the :samp:`\\u` and :samp:`\\U` escapes or used directly in the input
+encoding. If strict ISO C90 conformance is specified with an option
+such as :option:`-std`:samp:`=c90`, or :option:`-fno-extended-identifiers` is
+used, then those constructs are not permitted in identifiers.
+
+.. [#f1] UTF-16 does not meet the requirements of the C
+ standard for a wide character set, but the choice of 16-bit
+ ``wchar_t`` is enshrined in some system ABIs so we cannot fix
+ this.
\ No newline at end of file
diff --git a/gcc/doc/cpp/conditional-syntax.rst b/gcc/doc/cpp/conditional-syntax.rst
new file mode 100644
index 00000000000..73311228508
--- /dev/null
+++ b/gcc/doc/cpp/conditional-syntax.rst
@@ -0,0 +1,413 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _conditional-syntax:
+
+Conditional Syntax
+******************
+
+.. index:: #if
+
+A conditional in the C preprocessor begins with a :dfn:`conditional
+directive`: :samp:`#if`, :samp:`#ifdef` or :samp:`#ifndef`.
+
+.. toctree::
+ :maxdepth: 2
+
+
+.. _ifdef:
+
+Ifdef
+^^^^^
+
+.. index:: #ifdef
+
+.. index:: #endif
+
+The simplest sort of conditional is
+
+.. code-block:: c++
+
+ #ifdef MACRO
+
+ controlled text
+
+ #endif /* MACRO */
+
+.. index:: conditional group
+
+This block is called a :dfn:`conditional group`. :samp:`{controlled text}`
+will be included in the output of the preprocessor if and only if
+:samp:`{MACRO}` is defined. We say that the conditional :dfn:`succeeds` if
+:samp:`{MACRO}` is defined, :dfn:`fails` if it is not.
+
+The :samp:`{controlled text}` inside of a conditional can include
+preprocessing directives. They are executed only if the conditional
+succeeds. You can nest conditional groups inside other conditional
+groups, but they must be completely nested. In other words,
+:samp:`#endif` always matches the nearest :samp:`#ifdef` (or
+:samp:`#ifndef`, or :samp:`#if`). Also, you cannot start a conditional
+group in one file and end it in another.
+
+Even if a conditional fails, the :samp:`{controlled text}` inside it is
+still run through initial transformations and tokenization. Therefore,
+it must all be lexically valid C. Normally the only way this matters is
+that all comments and string literals inside a failing conditional group
+must still be properly ended.
+
+The comment following the :samp:`#endif` is not required, but it is a
+good practice if there is a lot of :samp:`{controlled text}`, because it
+helps people match the :samp:`#endif` to the corresponding :samp:`#ifdef`.
+Older programs sometimes put :samp:`{MACRO}` directly after the
+:samp:`#endif` without enclosing it in a comment. This is invalid code
+according to the C standard. CPP accepts it with a warning. It
+never affects which :samp:`#ifndef` the :samp:`#endif` matches.
+
+.. index:: #ifndef
+
+Sometimes you wish to use some code if a macro is *not* defined.
+You can do this by writing :samp:`#ifndef` instead of :samp:`#ifdef`.
+One common use of :samp:`#ifndef` is to include code only the first
+time a header file is included. See :ref:`once-only-headers`.
+
+Macro definitions can vary between compilations for several reasons.
+Here are some samples.
+
+* Some macros are predefined on each kind of machine
+ (see :ref:`system-specific-predefined-macros`). This allows you to provide
+ code specially tuned for a particular machine.
+
+* System header files define more macros, associated with the features
+ they implement. You can test these macros with conditionals to avoid
+ using a system feature on a machine where it is not implemented.
+
+* Macros can be defined or undefined with the :option:`-D` and :option:`-U`
+ command-line options when you compile the program. You can arrange to
+ compile the same source file into two different programs by choosing a
+ macro name to specify which program you want, writing conditionals to
+ test whether or how this macro is defined, and then controlling the
+ state of the macro with command-line options, perhaps set in the
+ Makefile. See :ref:`invocation`.
+
+* Your program might have a special header file (often called
+ :samp:`config.h`) that is adjusted when the program is compiled. It can
+ define or not define macros depending on the features of the system and
+ the desired capabilities of the program. The adjustment can be
+ automated by a tool such as :command:`autoconf`, or done by hand.
+
+.. _if:
+
+If
+^^
+
+The :samp:`#if` directive allows you to test the value of an arithmetic
+expression, rather than the mere existence of one macro. Its syntax is
+
+.. code-block:: c++
+
+ #if expression
+
+ controlled text
+
+ #endif /* expression */
+
+:samp:`{expression}` is a C expression of integer type, subject to stringent
+restrictions. It may contain
+
+* Integer constants.
+
+* Character constants, which are interpreted as they would be in normal
+ code.
+
+* Arithmetic operators for addition, subtraction, multiplication,
+ division, bitwise operations, shifts, comparisons, and logical
+ operations ( ``&&`` and ``||`` ). The latter two obey the usual
+ short-circuiting rules of standard C.
+
+* Macros. All macros in the expression are expanded before actual
+ computation of the expression's value begins.
+
+* Uses of the ``defined`` operator, which lets you check whether macros
+ are defined in the middle of an :samp:`#if`.
+
+* Identifiers that are not macros, which are all considered to be the
+ number zero. This allows you to write ``#if MACRO`` instead of
+ ``#ifdef MACRO``, if you know that MACRO, when defined, will
+ always have a nonzero value. Function-like macros used without their
+ function call parentheses are also treated as zero.
+
+ In some contexts this shortcut is undesirable. The :option:`-Wundef`
+ option causes GCC to warn whenever it encounters an identifier which is
+ not a macro in an :samp:`#if`.
+
+The preprocessor does not know anything about types in the language.
+Therefore, ``sizeof`` operators are not recognized in :samp:`#if`, and
+neither are ``enum`` constants. They will be taken as identifiers
+which are not macros, and replaced by zero. In the case of
+``sizeof``, this is likely to cause the expression to be invalid.
+
+The preprocessor calculates the value of :samp:`{expression}`. It carries
+out all calculations in the widest integer type known to the compiler;
+on most machines supported by GCC this is 64 bits. This is not the same
+rule as the compiler uses to calculate the value of a constant
+expression, and may give different results in some cases. If the value
+comes out to be nonzero, the :samp:`#if` succeeds and the :samp:`{controlled
+text}` is included; otherwise it is skipped.
+
+.. _defined:
+
+Defined
+^^^^^^^
+
+.. index:: defined
+
+The special operator ``defined`` is used in :samp:`#if` and
+:samp:`#elif` expressions to test whether a certain name is defined as a
+macro. ``defined name`` and ``defined (name)`` are
+both expressions whose value is 1 if :samp:`{name}` is defined as a macro at
+the current point in the program, and 0 otherwise. Thus, ``#if
+defined MACRO`` is precisely equivalent to ``#ifdef MACRO``.
+
+``defined`` is useful when you wish to test more than one macro for
+existence at once. For example,
+
+.. code-block:: c++
+
+ #if defined (__vax__) || defined (__ns16000__)
+
+would succeed if either of the names ``__vax__`` or
+``__ns16000__`` is defined as a macro.
+
+Conditionals written like this:
+
+.. code-block:: c++
+
+ #if defined BUFSIZE && BUFSIZE >= 1024
+
+can generally be simplified to just ``#if BUFSIZE >= 1024``,
+since if ``BUFSIZE`` is not defined, it will be interpreted as having
+the value zero.
+
+If the ``defined`` operator appears as a result of a macro expansion,
+the C standard says the behavior is undefined. GNU cpp treats it as a
+genuine ``defined`` operator and evaluates it normally. It will warn
+wherever your code uses this feature if you use the command-line option
+:option:`-Wpedantic`, since other compilers may handle it differently. The
+warning is also enabled by :option:`-Wextra`, and can also be enabled
+individually with :option:`-Wexpansion-to-defined`.
+
+.. _else:
+
+Else
+^^^^
+
+.. index:: #else
+
+The :samp:`#else` directive can be added to a conditional to provide
+alternative text to be used if the condition fails. This is what it
+looks like:
+
+.. code-block:: c++
+
+ #if expression
+ text-if-true
+ #else /* Not expression */
+ text-if-false
+ #endif /* Not expression */
+
+If :samp:`{expression}` is nonzero, the :samp:`{text-if-true}` is included and
+the :samp:`{text-if-false}` is skipped. If :samp:`{expression}` is zero, the
+opposite happens.
+
+You can use :samp:`#else` with :samp:`#ifdef` and :samp:`#ifndef`, too.
+
+.. _elif:
+
+Elif
+^^^^
+
+.. index:: #elif
+
+One common case of nested conditionals is used to check for more than two
+possible alternatives. For example, you might have
+
+.. code-block:: c++
+
+ #if X == 1
+ ...
+ #else /* X != 1 */
+ #if X == 2
+ ...
+ #else /* X != 2 */
+ ...
+ #endif /* X != 2 */
+ #endif /* X != 1 */
+
+Another conditional directive, :samp:`#elif`, allows this to be
+abbreviated as follows:
+
+.. code-block:: c++
+
+ #if X == 1
+ ...
+ #elif X == 2
+ ...
+ #else /* X != 2 and X != 1*/
+ ...
+ #endif /* X != 2 and X != 1*/
+
+:samp:`#elif` stands for 'else if'. Like :samp:`#else`, it goes in the
+middle of a conditional group and subdivides it; it does not require a
+matching :samp:`#endif` of its own. Like :samp:`#if`, the :samp:`#elif`
+directive includes an expression to be tested. The text following the
+:samp:`#elif` is processed only if the original :samp:`#if`-condition
+failed and the :samp:`#elif` condition succeeds.
+
+More than one :samp:`#elif` can go in the same conditional group. Then
+the text after each :samp:`#elif` is processed only if the :samp:`#elif`
+condition succeeds after the original :samp:`#if` and all previous
+:samp:`#elif` directives within it have failed.
+
+:samp:`#else` is allowed after any number of :samp:`#elif` directives, but
+:samp:`#elif` may not follow :samp:`#else`.
+
+__has_attribute
+^^^^^^^^^^^^^^^
+
+.. index:: __has_attribute
+
+The special operator ``__has_attribute (operand)`` may be used
+in :samp:`#if` and :samp:`#elif` expressions to test whether the attribute
+referenced by its :samp:`{operand}` is recognized by GCC. Using the operator
+in other contexts is not valid. In C code, if compiling for strict
+conformance to standards before C2x, :samp:`{operand}` must be
+a valid identifier. Otherwise, :samp:`{operand}` may be optionally
+introduced by the ``attribute-scope::`` prefix.
+The :samp:`{attribute-scope}` prefix identifies the 'namespace' within
+which the attribute is recognized. The scope of GCC attributes is
+:samp:`gnu` or :samp:`__gnu__`. The ``__has_attribute`` operator by
+itself, without any :samp:`{operand}` or parentheses, acts as a predefined
+macro so that support for it can be tested in portable code. Thus,
+the recommended use of the operator is as follows:
+
+.. code-block:: c++
+
+ #if defined __has_attribute
+ # if __has_attribute (nonnull)
+ # define ATTR_NONNULL __attribute__ ((nonnull))
+ # endif
+ #endif
+
+The first :samp:`#if` test succeeds only when the operator is supported
+by the version of GCC (or another compiler) being used. Only when that
+test succeeds is it valid to use ``__has_attribute`` as a preprocessor
+operator. As a result, combining the two tests into a single expression as
+shown below would only be valid with a compiler that supports the operator
+but not with others that don't.
+
+.. code-block:: c++
+
+ #if defined __has_attribute && __has_attribute (nonnull) /* not portable */
+ ...
+ #endif
+
+__has_cpp_attribute
+^^^^^^^^^^^^^^^^^^^
+
+.. index:: __has_cpp_attribute
+
+The special operator ``__has_cpp_attribute (operand)`` may be used
+in :samp:`#if` and :samp:`#elif` expressions in C++ code to test whether
+the attribute referenced by its :samp:`{operand}` is recognized by GCC.
+``__has_cpp_attribute (operand)`` is equivalent to
+``__has_attribute (operand)`` except that when :samp:`{operand}`
+designates a supported standard attribute it evaluates to an integer
+constant of the form ``YYYYMM`` indicating the year and month when
+the attribute was first introduced into the C++ standard. For additional
+information including the dates of the introduction of current standard
+attributes, see `SD-6: SG10 Feature Test Recommendations <https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations/>`_.
+
+__has_c_attribute
+^^^^^^^^^^^^^^^^^
+
+.. index:: __has_c_attribute
+
+The special operator ``__has_c_attribute (operand)`` may be
+used in :samp:`#if` and :samp:`#elif` expressions in C code to test
+whether the attribute referenced by its :samp:`{operand}` is recognized by
+GCC in attributes using the :samp:`[[]]` syntax. GNU attributes must
+be specified with the scope :samp:`gnu` or :samp:`__gnu__` with
+``__has_c_attribute``. When :samp:`{operand}` designates a supported
+standard attribute it evaluates to an integer constant of the form
+``YYYYMM`` indicating the year and month when the attribute was
+first introduced into the C standard, or when the syntax of operands
+to the attribute was extended in the C standard.
+
+__has_builtin
+^^^^^^^^^^^^^
+
+.. index:: __has_builtin
+
+The special operator ``__has_builtin (operand)`` may be used in
+constant integer contexts and in preprocessor :samp:`#if` and :samp:`#elif`
+expressions to test whether the symbol named by its :samp:`{operand}` is
+recognized as a built-in function by GCC in the current language and
+conformance mode. It evaluates to a constant integer with a nonzero
+value if the argument refers to such a function, and to zero otherwise.
+The operator may also be used in preprocessor :samp:`#if` and :samp:`#elif`
+expressions. The ``__has_builtin`` operator by itself, without any
+:samp:`{operand}` or parentheses, acts as a predefined macro so that support
+for it can be tested in portable code. Thus, the recommended use of
+the operator is as follows:
+
+.. code-block:: c++
+
+ #if defined __has_builtin
+ # if __has_builtin (__builtin_object_size)
+ # define builtin_object_size(ptr) __builtin_object_size (ptr, 2)
+ # endif
+ #endif
+ #ifndef builtin_object_size
+ # define builtin_object_size(ptr) ((size_t)-1)
+ #endif
+
+__has_include
+^^^^^^^^^^^^^
+
+.. index:: __has_include
+
+The special operator ``__has_include (operand)`` may be used in
+:samp:`#if` and :samp:`#elif` expressions to test whether the header referenced
+by its :samp:`{operand}` can be included using the :samp:`#include` directive. Using
+the operator in other contexts is not valid. The :samp:`{operand}` takes
+the same form as the file in the :samp:`#include` directive (see :ref:`include-syntax`) and evaluates to a nonzero value if the header can be included and
+to zero otherwise. Note that that the ability to include a header doesn't
+imply that the header doesn't contain invalid constructs or :samp:`#error`
+directives that would cause the preprocessor to fail.
+
+The ``__has_include`` operator by itself, without any :samp:`{operand}` or
+parentheses, acts as a predefined macro so that support for it can be tested
+in portable code. Thus, the recommended use of the operator is as follows:
+
+.. code-block:: c++
+
+ #if defined __has_include
+ # if __has_include (<stdatomic.h>)
+ # include <stdatomic.h>
+ # endif
+ #endif
+
+The first :samp:`#if` test succeeds only when the operator is supported
+by the version of GCC (or another compiler) being used. Only when that
+test succeeds is it valid to use ``__has_include`` as a preprocessor
+operator. As a result, combining the two tests into a single expression
+as shown below would only be valid with a compiler that supports the operator
+but not with others that don't.
+
+.. code-block:: c++
+
+ #if defined __has_include && __has_include ("header.h") /* not portable */
+ ...
+ #endif
\ No newline at end of file
diff --git a/gcc/doc/cpp/conditional-uses.rst b/gcc/doc/cpp/conditional-uses.rst
new file mode 100644
index 00000000000..0418a9af710
--- /dev/null
+++ b/gcc/doc/cpp/conditional-uses.rst
@@ -0,0 +1,32 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _conditional-uses:
+
+Conditional Uses
+****************
+
+There are three general reasons to use a conditional.
+
+* A program may need to use different code depending on the machine or
+ operating system it is to run on. In some cases the code for one
+ operating system may be erroneous on another operating system; for
+ example, it might refer to data types or constants that do not exist on
+ the other system. When this happens, it is not enough to avoid
+ executing the invalid code. Its mere presence will cause the compiler
+ to reject the program. With a preprocessing conditional, the offending
+ code can be effectively excised from the program when it is not valid.
+
+* You may want to be able to compile the same source file into two
+ different programs. One version might make frequent time-consuming
+ consistency checks on its intermediate data, or print the values of
+ those data for debugging, and the other not.
+
+* A conditional whose condition is always false is one way to exclude code
+ from the program but keep it as a sort of comment for future reference.
+
+Simple programs that do not need system-specific logic or complex
+debugging hooks generally will not need to use preprocessing
+conditionals.
\ No newline at end of file
diff --git a/gcc/doc/cpp/conditionals.rst b/gcc/doc/cpp/conditionals.rst
new file mode 100644
index 00000000000..4ef20544394
--- /dev/null
+++ b/gcc/doc/cpp/conditionals.rst
@@ -0,0 +1,44 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _conditionals:
+
+Conditionals
+------------
+
+.. index:: conditionals
+
+A :dfn:`conditional` is a directive that instructs the preprocessor to
+select whether or not to include a chunk of code in the final token
+stream passed to the compiler. Preprocessor conditionals can test
+arithmetic expressions, or whether a name is defined as a macro, or both
+simultaneously using the special ``defined`` operator.
+
+A conditional in the C preprocessor resembles in some ways an ``if``
+statement in C, but it is important to understand the difference between
+them. The condition in an ``if`` statement is tested during the
+execution of your program. Its purpose is to allow your program to
+behave differently from run to run, depending on the data it is
+operating on. The condition in a preprocessing conditional directive is
+tested when your program is compiled. Its purpose is to allow different
+code to be included in the program depending on the situation at the
+time of compilation.
+
+However, the distinction is becoming less clear. Modern compilers often
+do test ``if`` statements when a program is compiled, if their
+conditions are known not to vary at run time, and eliminate code which
+can never be executed. If you can count on your compiler to do this,
+you may find that your program is more readable if you use ``if``
+statements with constant conditions (perhaps determined by macros). Of
+course, you can only use this to exclude code, not type definitions or
+other preprocessing directives, and you can only do it if the code
+remains syntactically valid when it is not to be used.
+
+.. toctree::
+ :maxdepth: 2
+
+ conditional-uses
+ conditional-syntax
+ deleted-code
\ No newline at end of file
diff --git a/gcc/doc/cpp/conf.py b/gcc/doc/cpp/conf.py
new file mode 100644
index 00000000000..2363a677b49
--- /dev/null
+++ b/gcc/doc/cpp/conf.py
@@ -0,0 +1,29 @@
+# Configuration file for the Sphinx documentation builder.
+
+import sys
+sys.path.append('../../..//doc')
+
+from baseconf import *
+
+project = 'The C Preprocessor'
+copyright = '1987-2021 Free Software Foundation, Inc.'
+authors = 'Richard M. Stallman, Zachary Weinberg'
+
+# Grouping the document tree into Texinfo files. List of tuples
+# (source start file, target name, title, author,
+# dir menu entry, description, category)
+latex_documents = [
+ ('index', 'cpp.tex', project, authors, 'manual'),
+]
+
+# One entry per manual page. List of tuples
+# (source start file, name, description, authors, manual section).
+man_pages = [
+ ('invocation', 'cpp', project, [authors], 1),
+]
+
+texinfo_documents = [
+ ('index', 'cpp', project, authors, None, None, None, True)
+]
+
+tags.add('cpp')
\ No newline at end of file
diff --git a/gcc/doc/cpp/copyright.rst b/gcc/doc/cpp/copyright.rst
new file mode 100644
index 00000000000..8e6b42353d3
--- /dev/null
+++ b/gcc/doc/cpp/copyright.rst
@@ -0,0 +1 @@
+.. include:: ../../../doc/copyright.rst
\ No newline at end of file
diff --git a/gcc/doc/cpp/deleted-code.rst b/gcc/doc/cpp/deleted-code.rst
new file mode 100644
index 00000000000..53340ccd672
--- /dev/null
+++ b/gcc/doc/cpp/deleted-code.rst
@@ -0,0 +1,34 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _deleted-code:
+
+Deleted Code
+************
+
+.. index:: commenting out code
+
+If you replace or delete a part of the program but want to keep the old
+code around for future reference, you often cannot simply comment it
+out. Block comments do not nest, so the first comment inside the old
+code will end the commenting-out. The probable result is a flood of
+syntax errors.
+
+One way to avoid this problem is to use an always-false conditional
+instead. For instance, put ``#if 0`` before the deleted code and
+``#endif`` after it. This works even if the code being turned
+off contains conditionals, but they must be entire conditionals
+(balanced :samp:`#if` and :samp:`#endif`).
+
+Some people use ``#ifdef notdef`` instead. This is risky, because
+``notdef`` might be accidentally defined as a macro, and then the
+conditional would succeed. ``#if 0`` can be counted on to fail.
+
+Do not use ``#if 0`` for comments which are not C code. Use a real
+comment, instead. The interior of ``#if 0`` must consist of complete
+tokens; in particular, single-quote characters must balance. Comments
+often contain unbalanced single-quote characters (known in English as
+apostrophes). These confuse ``#if 0``. They don't confuse
+:samp:`/*`.
\ No newline at end of file
diff --git a/gcc/doc/cpp/diagnostics.rst b/gcc/doc/cpp/diagnostics.rst
new file mode 100644
index 00000000000..092d31796e1
--- /dev/null
+++ b/gcc/doc/cpp/diagnostics.rst
@@ -0,0 +1,57 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _diagnostics:
+
+Diagnostics
+-----------
+
+.. index:: diagnostic
+
+.. index:: reporting errors
+
+.. index:: reporting warnings
+
+.. index:: #error
+
+The directive :samp:`#error` causes the preprocessor to report a fatal
+error. The tokens forming the rest of the line following :samp:`#error`
+are used as the error message.
+
+You would use :samp:`#error` inside of a conditional that detects a
+combination of parameters which you know the program does not properly
+support. For example, if you know that the program will not run
+properly on a VAX, you might write
+
+.. code-block:: c++
+
+ #ifdef __vax__
+ #error "Won't work on VAXen. See comments at get_last_object."
+ #endif
+
+If you have several configuration parameters that must be set up by
+the installation in a consistent way, you can use conditionals to detect
+an inconsistency and report it with :samp:`#error`. For example,
+
+.. code-block:: c++
+
+ #if !defined(FOO) && defined(BAR)
+ #error "BAR requires FOO."
+ #endif
+
+.. index:: #warning
+
+The directive :samp:`#warning` is like :samp:`#error`, but causes the
+preprocessor to issue a warning and continue preprocessing. The tokens
+following :samp:`#warning` are used as the warning message.
+
+You might use :samp:`#warning` in obsolete header files, with a message
+directing the user to the header file which should be used instead.
+
+Neither :samp:`#error` nor :samp:`#warning` macro-expands its argument.
+Internal whitespace sequences are each replaced with a single space.
+The line must consist of complete tokens. It is wisest to make the
+argument of these directives be a single string constant; this avoids
+problems with apostrophes and the like.
\ No newline at end of file
diff --git a/gcc/doc/cpp/environment-variables.rst b/gcc/doc/cpp/environment-variables.rst
new file mode 100644
index 00000000000..7c8a60df259
--- /dev/null
+++ b/gcc/doc/cpp/environment-variables.rst
@@ -0,0 +1,26 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _environment-variables:
+
+Environment Variables
+---------------------
+
+.. index:: environment variables
+
+This section describes the environment variables that affect how CPP
+operates. You can use them to specify directories or prefixes to use
+when searching for include files, or to control dependency output.
+
+Note that you can also specify places to search using options such as
+:option:`-I`, and control dependency output with options like
+:option:`-M` (see :ref:`invocation`). These take precedence over
+environment variables, which in turn take precedence over the
+configuration of GCC.
+
+.. include:: ../../../doc/cppenv.rst
+
+
+.. Special handling for inclusion in the install manual.
\ No newline at end of file
diff --git a/gcc/doc/cpp/gnu-free-documentation-license.rst b/gcc/doc/cpp/gnu-free-documentation-license.rst
new file mode 100644
index 00000000000..a9f00f268fa
--- /dev/null
+++ b/gcc/doc/cpp/gnu-free-documentation-license.rst
@@ -0,0 +1,6 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. include:: ../../../doc/gnu_free_documentation_license.rst
\ No newline at end of file
--git a/gcc/doc/cpp/header-files.rst b/gcc/doc/cpp/header-files.rst
new file mode 100644
index 00000000000..8583233f800
--- /dev/null
+++ b/gcc/doc/cpp/header-files.rst
@@ -0,0 +1,57 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _header-files:
+
+Header Files
+------------
+
+.. index:: header file
+
+A header file is a file containing C declarations and macro definitions
+(see :ref:`macros`) to be shared between several source files. You request
+the use of a header file in your program by :dfn:`including` it, with the
+C preprocessing directive :samp:`#include`.
+
+Header files serve two purposes.
+
+*
+ .. index:: system header files
+
+ System header files declare the interfaces to parts of the operating
+ system. You include them in your program to supply the definitions and
+ declarations you need to invoke system calls and libraries.
+
+* Your own header files contain declarations for interfaces between the
+ source files of your program. Each time you have a group of related
+ declarations and macro definitions all or most of which are needed in
+ several different source files, it is a good idea to create a header
+ file for them.
+
+Including a header file produces the same results as copying the header
+file into each source file that needs it. Such copying would be
+time-consuming and error-prone. With a header file, the related
+declarations appear in only one place. If they need to be changed, they
+can be changed in one place, and programs that include the header file
+will automatically use the new version when next recompiled. The header
+file eliminates the labor of finding and changing all the copies as well
+as the risk that a failure to find one copy will result in
+inconsistencies within a program.
+
+In C, the usual convention is to give header files names that end with
+:samp:`.h`. It is most portable to use only letters, digits, dashes, and
+underscores in header file names, and at most one dot.
+
+.. toctree::
+ :maxdepth: 2
+
+ header-files/include-syntax
+ header-files/include-operation
+ header-files/search-path
+ header-files/once-only-headers
+ header-files/alternatives-to-wrapper-#ifndef
+ header-files/computed-includes
+ header-files/wrapper-headers
+ header-files/system-headers
\ No newline at end of file
diff --git a/gcc/doc/cpp/header-files/alternatives-to-wrapper-#ifndef.rst b/gcc/doc/cpp/header-files/alternatives-to-wrapper-#ifndef.rst
new file mode 100644
index 00000000000..1674ba6f018
--- /dev/null
+++ b/gcc/doc/cpp/header-files/alternatives-to-wrapper-#ifndef.rst
@@ -0,0 +1,40 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _alternatives-to-wrapper-#ifndef:
+
+Alternatives to Wrapper #ifndef
+*******************************
+
+CPP supports two more ways of indicating that a header file should be
+read only once. Neither one is as portable as a wrapper :samp:`#ifndef`
+and we recommend you do not use them in new programs, with the caveat
+that :samp:`#import` is standard practice in Objective-C.
+
+.. index:: #import
+
+CPP supports a variant of :samp:`#include` called :samp:`#import` which
+includes a file, but does so at most once. If you use :samp:`#import`
+instead of :samp:`#include`, then you don't need the conditionals
+inside the header file to prevent multiple inclusion of the contents.
+:samp:`#import` is standard in Objective-C, but is considered a
+deprecated extension in C and C++.
+
+:samp:`#import` is not a well designed feature. It requires the users of
+a header file to know that it should only be included once. It is much
+better for the header file's implementor to write the file so that users
+don't need to know this. Using a wrapper :samp:`#ifndef` accomplishes
+this goal.
+
+In the present implementation, a single use of :samp:`#import` will
+prevent the file from ever being read again, by either :samp:`#import` or
+:samp:`#include`. You should not rely on this; do not use both
+:samp:`#import` and :samp:`#include` to refer to the same header file.
+
+Another way to prevent a header file from being included more than once
+is with the :samp:`#pragma once` directive (see :ref:`pragmas`).
+:samp:`#pragma once` does not have the problems that :samp:`#import` does,
+but it is not recognized by all preprocessors, so you cannot rely on it
+in a portable program.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/computed-includes.rst b/gcc/doc/cpp/header-files/computed-includes.rst
new file mode 100644
index 00000000000..cf4a2b67b0b
--- /dev/null
+++ b/gcc/doc/cpp/header-files/computed-includes.rst
@@ -0,0 +1,88 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _computed-includes:
+
+Computed Includes
+*****************
+
+.. index:: computed includes
+
+.. index:: macros in include
+
+Sometimes it is necessary to select one of several different header
+files to be included into your program. They might specify
+configuration parameters to be used on different sorts of operating
+systems, for instance. You could do this with a series of conditionals,
+
+.. code-block:: c++
+
+ #if SYSTEM_1
+ # include "system_1.h"
+ #elif SYSTEM_2
+ # include "system_2.h"
+ #elif SYSTEM_3
+ ...
+ #endif
+
+That rapidly becomes tedious. Instead, the preprocessor offers the
+ability to use a macro for the header name. This is called a
+:dfn:`computed include`. Instead of writing a header name as the direct
+argument of :samp:`#include`, you simply put a macro name there instead:
+
+.. code-block:: c++
+
+ #define SYSTEM_H "system_1.h"
+ ...
+ #include SYSTEM_H
+
+``SYSTEM_H`` will be expanded, and the preprocessor will look for
+:samp:`system_1.h` as if the :samp:`#include` had been written that way
+originally. ``SYSTEM_H`` could be defined by your Makefile with a
+:option:`-D` option.
+
+You must be careful when you define the macro. :samp:`#define` saves
+tokens, not text. The preprocessor has no way of knowing that the macro
+will be used as the argument of :samp:`#include`, so it generates
+ordinary tokens, not a header name. This is unlikely to cause problems
+if you use double-quote includes, which are close enough to string
+constants. If you use angle brackets, however, you may have trouble.
+
+The syntax of a computed include is actually a bit more general than the
+above. If the first non-whitespace character after :samp:`#include` is
+not :samp:`"` or :samp:`<`, then the entire line is macro-expanded
+like running text would be.
+
+If the line expands to a single string constant, the contents of that
+string constant are the file to be included. CPP does not re-examine the
+string for embedded quotes, but neither does it process backslash
+escapes in the string. Therefore
+
+.. code-block:: c++
+
+ #define HEADER "a\"b"
+ #include HEADER
+
+looks for a file named :samp:`a\\"b`. CPP searches for the file according
+to the rules for double-quoted includes.
+
+If the line expands to a token stream beginning with a :samp:`<` token
+and including a :samp:`>` token, then the tokens between the :samp:`<` and
+the first :samp:`>` are combined to form the filename to be included.
+Any whitespace between tokens is reduced to a single space; then any
+space after the initial :samp:`<` is retained, but a trailing space
+before the closing :samp:`>` is ignored. CPP searches for the file
+according to the rules for angle-bracket includes.
+
+In either case, if there are any tokens on the line after the file name,
+an error occurs and the directive is not processed. It is also an error
+if the result of expansion does not match either of the two expected
+forms.
+
+These rules are implementation-defined behavior according to the C
+standard. To minimize the risk of different compilers interpreting your
+computed includes differently, we recommend you use only a single
+object-like macro which expands to a string constant. This will also
+minimize confusion for people reading your program.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/include-operation.rst b/gcc/doc/cpp/header-files/include-operation.rst
new file mode 100644
index 00000000000..966dfcb28ab
--- /dev/null
+++ b/gcc/doc/cpp/header-files/include-operation.rst
@@ -0,0 +1,67 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _include-operation:
+
+Include Operation
+*****************
+
+The :samp:`#include` directive works by directing the C preprocessor to
+scan the specified file as input before continuing with the rest of the
+current file. The output from the preprocessor contains the output
+already generated, followed by the output resulting from the included
+file, followed by the output that comes from the text after the
+:samp:`#include` directive. For example, if you have a header file
+:samp:`header.h` as follows,
+
+.. code-block:: c++
+
+ char *test (void);
+
+and a main program called :samp:`program.c` that uses the header file,
+like this,
+
+.. code-block:: c++
+
+ int x;
+ #include "header.h"
+
+ int
+ main (void)
+ {
+ puts (test ());
+ }
+
+the compiler will see the same token stream as it would if
+:samp:`program.c` read
+
+.. code-block:: c++
+
+ int x;
+ char *test (void);
+
+ int
+ main (void)
+ {
+ puts (test ());
+ }
+
+Included files are not limited to declarations and macro definitions;
+those are merely the typical uses. Any fragment of a C program can be
+included from another file. The include file could even contain the
+beginning of a statement that is concluded in the containing file, or
+the end of a statement that was started in the including file. However,
+an included file must consist of complete tokens. Comments and string
+literals which have not been closed by the end of an included file are
+invalid. For error recovery, they are considered to end at the end of
+the file.
+
+To avoid confusion, it is best if header files contain only complete
+syntactic units---function declarations or definitions, type
+declarations, etc.
+
+The line following the :samp:`#include` directive is always treated as a
+separate line by the C preprocessor, even if the included file lacks a
+final newline.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/include-syntax.rst b/gcc/doc/cpp/header-files/include-syntax.rst
new file mode 100644
index 00000000000..757dace51ea
--- /dev/null
+++ b/gcc/doc/cpp/header-files/include-syntax.rst
@@ -0,0 +1,42 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _include-syntax:
+
+Include Syntax
+**************
+
+.. index:: #include
+
+Both user and system header files are included using the preprocessing
+directive :samp:`#include`. It has two variants:
+
+:samp:`#include <{file}>`
+ This variant is used for system header files. It searches for a file
+ named :samp:`{file}` in a standard list of system directories. You can prepend
+ directories to this list with the :option:`-I` option (see :ref:`invocation`).
+
+:samp:`#include "{file}"`
+ This variant is used for header files of your own program. It
+ searches for a file named :samp:`{file}` first in the directory containing
+ the current file, then in the quote directories and then the same
+ directories used for ``<file>``. You can prepend directories
+ to the list of quote directories with the :option:`-iquote` option.
+
+The argument of :samp:`#include`, whether delimited with quote marks or
+angle brackets, behaves like a string constant in that comments are not
+recognized, and macro names are not expanded. Thus, ``#include
+<x/*y>`` specifies inclusion of a system header file named :samp:`x/*y`.
+
+However, if backslashes occur within :samp:`{file}`, they are considered
+ordinary text characters, not escape characters. None of the character
+escape sequences appropriate to string constants in C are processed.
+Thus, ``#include "x\n\\y"`` specifies a filename containing three
+backslashes. (Some systems interpret :samp:`\\` as a pathname separator.
+All of these also interpret :samp:`/` the same way. It is most portable
+to use only :samp:`/`.)
+
+It is an error if there is anything (other than comments) on the line
+after the file name.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/once-only-headers.rst b/gcc/doc/cpp/header-files/once-only-headers.rst
new file mode 100644
index 00000000000..aa6ee950320
--- /dev/null
+++ b/gcc/doc/cpp/header-files/once-only-headers.rst
@@ -0,0 +1,58 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _once-only-headers:
+
+Once-Only Headers
+*****************
+
+.. index:: repeated inclusion
+
+.. index:: including just once
+
+.. index:: wrapper #ifndef
+
+If a header file happens to be included twice, the compiler will process
+its contents twice. This is very likely to cause an error, e.g. when the
+compiler sees the same structure definition twice. Even if it does not,
+it will certainly waste time.
+
+The standard way to prevent this is to enclose the entire real contents
+of the file in a conditional, like this:
+
+.. code-block:: c++
+
+ /* File foo. */
+ #ifndef FILE_FOO_SEEN
+ #define FILE_FOO_SEEN
+
+ the entire file
+
+ #endif /* !FILE_FOO_SEEN */
+
+This construct is commonly known as a :dfn:`wrapper #ifndef`.
+When the header is included again, the conditional will be false,
+because ``FILE_FOO_SEEN`` is defined. The preprocessor will skip
+over the entire contents of the file, and the compiler will not see it
+twice.
+
+CPP optimizes even further. It remembers when a header file has a
+wrapper :samp:`#ifndef`. If a subsequent :samp:`#include` specifies that
+header, and the macro in the :samp:`#ifndef` is still defined, it does
+not bother to rescan the file at all.
+
+You can put comments outside the wrapper. They will not interfere with
+this optimization.
+
+.. index:: controlling macro
+
+.. index:: guard macro
+
+The macro ``FILE_FOO_SEEN`` is called the :dfn:`controlling macro` or
+:dfn:`guard macro`. In a user header file, the macro name should not
+begin with :samp:`_`. In a system header file, it should begin with
+:samp:`__` to avoid conflicts with user programs. In any kind of header
+file, the macro name should contain the name of the file and some
+additional text, to avoid conflicts with other header files.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/search-path.rst b/gcc/doc/cpp/header-files/search-path.rst
new file mode 100644
index 00000000000..d421235e6a8
--- /dev/null
+++ b/gcc/doc/cpp/header-files/search-path.rst
@@ -0,0 +1,53 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _search-path:
+
+Search Path
+***********
+
+By default, the preprocessor looks for header files included by the quote
+form of the directive ``#include "file"`` first relative to
+the directory of the current file, and then in a preconfigured list
+of standard system directories.
+For example, if :samp:`/usr/include/sys/stat.h` contains
+``#include "types.h"``, GCC looks for :samp:`types.h` first in
+:samp:`/usr/include/sys`, then in its usual search path.
+
+For the angle-bracket form ``#include <file>``, the
+preprocessor's default behavior is to look only in the standard system
+directories. The exact search directory list depends on the target
+system, how GCC is configured, and where it is installed. You can
+find the default search directory list for your version of CPP by
+invoking it with the :option:`-v` option. For example,
+
+.. code-block:: c++
+
+ cpp -v /dev/null -o /dev/null
+
+There are a number of command-line options you can use to add
+additional directories to the search path.
+The most commonly-used option is :option:`-I`:samp:`{dir}`, which causes
+:samp:`{dir}` to be searched after the current directory (for the quote
+form of the directive) and ahead of the standard system directories.
+You can specify multiple :option:`-I` options on the command line,
+in which case the directories are searched in left-to-right order.
+
+If you need separate control over the search paths for the quote and
+angle-bracket forms of the :samp:`#include` directive, you can use the
+:option:`-iquote` and/or :option:`-isystem` options instead of :option:`-I`.
+See :ref:`invocation`, for a detailed description of these options, as
+well as others that are less generally useful.
+
+If you specify other options on the command line, such as :option:`-I`,
+that affect where the preprocessor searches for header files, the
+directory list printed by the :option:`-v` option reflects the actual
+search path used by the preprocessor.
+
+Note that you can also prevent the preprocessor from searching any of
+the default system header directories with the :option:`-nostdinc`
+option. This is useful when you are compiling an operating system
+kernel or some other program that does not use the standard C library
+facilities, or the standard C library itself.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/system-headers.rst b/gcc/doc/cpp/header-files/system-headers.rst
new file mode 100644
index 00000000000..b5475471eaf
--- /dev/null
+++ b/gcc/doc/cpp/header-files/system-headers.rst
@@ -0,0 +1,41 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _system-headers:
+
+System Headers
+**************
+
+.. index:: system header files
+
+The header files declaring interfaces to the operating system and
+runtime libraries often cannot be written in strictly conforming C.
+Therefore, GCC gives code found in :dfn:`system headers` special
+treatment. All warnings, other than those generated by :samp:`#warning`
+(see :ref:`diagnostics`), are suppressed while GCC is processing a system
+header. Macros defined in a system header are immune to a few warnings
+wherever they are expanded. This immunity is granted on an ad-hoc
+basis, when we find that a warning generates lots of false positives
+because of code in macros defined in system headers.
+
+Normally, only the headers found in specific directories are considered
+system headers. These directories are determined when GCC is compiled.
+There are, however, two ways to make normal headers into system headers:
+
+* Header files found in directories added to the search path with the
+ :option:`-isystem` and :option:`-idirafter` command-line options are
+ treated as system headers for the purposes of diagnostics.
+
+*
+ .. index:: #pragma GCC system_header
+
+ There is also a directive, ``#pragma GCC system_header``, which
+ tells GCC to consider the rest of the current include file a system
+ header, no matter where it was found. Code that comes before the
+ :samp:`#pragma` in the file is not affected. ``#pragma GCC
+ system_header`` has no effect in the primary source file.
+
+On some targets, such as RS/6000 AIX, GCC implicitly surrounds all
+system headers with an :samp:`extern "C"` block when compiling as C++.
\ No newline at end of file
--git a/gcc/doc/cpp/header-files/wrapper-headers.rst b/gcc/doc/cpp/header-files/wrapper-headers.rst
new file mode 100644
index 00000000000..7ccd8725576
--- /dev/null
+++ b/gcc/doc/cpp/header-files/wrapper-headers.rst
@@ -0,0 +1,62 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _wrapper-headers:
+
+Wrapper Headers
+***************
+
+.. index:: wrapper headers
+
+.. index:: overriding a header file
+
+.. index:: #include_next
+
+Sometimes it is necessary to adjust the contents of a system-provided
+header file without editing it directly. GCC's :command:`fixincludes`
+operation does this, for example. One way to do that would be to create
+a new header file with the same name and insert it in the search path
+before the original header. That works fine as long as you're willing
+to replace the old header entirely. But what if you want to refer to
+the old header from the new one?
+
+You cannot simply include the old header with :samp:`#include`. That
+will start from the beginning, and find your new header again. If your
+header is not protected from multiple inclusion (see :ref:`once-only-headers`), it will recurse infinitely and cause a fatal error.
+
+You could include the old header with an absolute pathname:
+
+.. code-block:: c++
+
+ #include "/usr/include/old-header.h"
+
+This works, but is not clean; should the system headers ever move, you
+would have to edit the new headers to match.
+
+There is no way to solve this problem within the C standard, but you can
+use the GNU extension :samp:`#include_next`. It means, 'Include the
+*next* file with this name'. This directive works like
+:samp:`#include` except in searching for the specified file: it starts
+searching the list of header file directories *after* the directory
+in which the current file was found.
+
+Suppose you specify :option:`-I /usr/local/include`, and the list of
+directories to search also includes :samp:`/usr/include`; and suppose
+both directories contain :samp:`signal.h`. Ordinary ``#include
+<signal.h>`` finds the file under :samp:`/usr/local/include`. If that
+file contains ``#include_next <signal.h>``, it starts searching
+after that directory, and finds the file in :samp:`/usr/include`.
+
+:samp:`#include_next` does not distinguish between ``<file>``
+and ``"file"`` inclusion, nor does it check that the file you
+specify has the same name as the current file. It simply looks for the
+file named, starting with the directory in the search path after the one
+where the current file was found.
+
+The use of :samp:`#include_next` can lead to great confusion. We
+recommend it be used only when there is no other alternative. In
+particular, it should not be used in the headers belonging to a specific
+program; it should be used only to make global corrections along the
+lines of :command:`fixincludes`.
\ No newline at end of file
diff --git a/gcc/doc/cpp/implementation-defined-behavior.rst b/gcc/doc/cpp/implementation-defined-behavior.rst
new file mode 100644
index 00000000000..f45530c960f
--- /dev/null
+++ b/gcc/doc/cpp/implementation-defined-behavior.rst
@@ -0,0 +1,99 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _implementation-defined-behavior:
+
+Implementation-defined behavior
+*******************************
+
+.. index:: implementation-defined behavior
+
+This is how CPP behaves in all the cases which the C standard
+describes as :dfn:`implementation-defined`. This term means that the
+implementation is free to do what it likes, but must document its choice
+and stick to it.
+
+.. FIXME: Check the C++ standard for more implementation-defined stuff.
+
+* The mapping of physical source file multi-byte characters to the
+ execution character set.
+
+ The input character set can be specified using the
+ :option:`-finput-charset` option, while the execution character set may
+ be controlled using the :option:`-fexec-charset` and
+ :option:`-fwide-exec-charset` options.
+
+* Identifier characters.
+
+.. _identifier-characters:
+
+ The C and C++ standards allow identifiers to be composed of :samp:`_`
+ and the alphanumeric characters. C++ also allows universal character
+ names. C99 and later C standards permit both universal character
+ names and implementation-defined characters. In both C and C++ modes,
+ GCC accepts in identifiers exactly those extended characters that
+ correspond to universal character names permitted by the chosen
+ standard.
+
+ GCC allows the :samp:`$` character in identifiers as an extension for
+ most targets. This is true regardless of the std = switch,
+ since this extension cannot conflict with standards-conforming
+ programs. When preprocessing assembler, however, dollars are not
+ identifier characters by default.
+
+ Currently the targets that by default do not permit :samp:`$` are AVR,
+ IP2K, MMIX, MIPS Irix 3, ARM aout, and PowerPC targets for the AIX
+ operating system.
+
+ You can override the default with :option:`-fdollars-in-identifiers` or
+ fno-dollars-in-identifiers. See :ref:`fdollars-in-identifiers`.
+
+* Non-empty sequences of whitespace characters.
+
+ In textual output, each whitespace sequence is collapsed to a single
+ space. For aesthetic reasons, the first token on each non-directive
+ line of output is preceded with sufficient spaces that it appears in the
+ same column as it did in the original source file.
+
+* The numeric value of character constants in preprocessor expressions.
+
+ The preprocessor and compiler interpret character constants in the
+ same way; i.e. escape sequences such as :samp:`\\a` are given the
+ values they would have on the target machine.
+
+ The compiler evaluates a multi-character character constant a character
+ at a time, shifting the previous value left by the number of bits per
+ target character, and then or-ing in the bit-pattern of the new
+ character truncated to the width of a target character. The final
+ bit-pattern is given type ``int``, and is therefore signed,
+ regardless of whether single characters are signed or not.
+ If there are more
+ characters in the constant than would fit in the target ``int`` the
+ compiler issues a warning, and the excess leading characters are
+ ignored.
+
+ For example, ``'ab'`` for a target with an 8-bit ``char`` would be
+ interpreted as :samp:`(int) ((unsigned char) 'a' * 256 + (unsigned char)
+ 'b')`, and ``'\234a'`` as :samp:`(int) ((unsigned char) '\\234' *
+ 256 + (unsigned char) 'a')`.
+
+* Source file inclusion.
+
+ For a discussion on how the preprocessor locates header files,
+ Include Operation.
+
+* Interpretation of the filename resulting from a macro-expanded
+ :samp:`#include` directive.
+
+ See :ref:`computed-includes`.
+
+* Treatment of a :samp:`#pragma` directive that after macro-expansion
+ results in a standard pragma.
+
+ No macro expansion occurs on any :samp:`#pragma` directive line, so the
+ question does not arise.
+
+ Note that GCC does not yet implement any of the standard
+ pragmas.
\ No newline at end of file
diff --git a/gcc/doc/cpp/implementation-details.rst b/gcc/doc/cpp/implementation-details.rst
new file mode 100644
index 00000000000..f5c3f2a1238
--- /dev/null
+++ b/gcc/doc/cpp/implementation-details.rst
@@ -0,0 +1,23 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _implementation-details:
+
+Implementation Details
+----------------------
+
+Here we document details of how the preprocessor's implementation
+affects its user-visible behavior. You should try to avoid undue
+reliance on behavior described here, as it is possible that it will
+change subtly in future implementations.
+
+Also documented here are obsolete features still supported by CPP.
+
+.. toctree::
+ :maxdepth: 2
+
+ implementation-defined-behavior
+ implementation-limits
+ obsolete-features
\ No newline at end of file
diff --git a/gcc/doc/cpp/implementation-limits.rst b/gcc/doc/cpp/implementation-limits.rst
new file mode 100644
index 00000000000..fedfcbdd1be
--- /dev/null
+++ b/gcc/doc/cpp/implementation-limits.rst
@@ -0,0 +1,68 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _implementation-limits:
+
+Implementation limits
+*********************
+
+.. index:: implementation limits
+
+CPP has a small number of internal limits. This section lists the
+limits which the C standard requires to be no lower than some minimum,
+and all the others known. It is intended that there should be as few limits
+as possible. If you encounter an undocumented or inconvenient limit,
+please report that as a bug. See :ref:`Reporting Bugs <bugs>`.
+
+Where we say something is limited :dfn:`only by available memory`, that
+means that internal data structures impose no intrinsic limit, and space
+is allocated with ``malloc`` or equivalent. The actual limit will
+therefore depend on many things, such as the size of other things
+allocated by the compiler at the same time, the amount of memory
+consumed by other processes on the same computer, etc.
+
+* Nesting levels of :samp:`#include` files.
+
+ We impose an arbitrary limit of 200 levels, to avoid runaway recursion.
+ The standard requires at least 15 levels.
+
+* Nesting levels of conditional inclusion.
+
+ The C standard mandates this be at least 63. CPP is limited only by
+ available memory.
+
+* Levels of parenthesized expressions within a full expression.
+
+ The C standard requires this to be at least 63. In preprocessor
+ conditional expressions, it is limited only by available memory.
+
+* Significant initial characters in an identifier or macro name.
+
+ The preprocessor treats all characters as significant. The C standard
+ requires only that the first 63 be significant.
+
+* Number of macros simultaneously defined in a single translation unit.
+
+ The standard requires at least 4095 be possible. CPP is limited only
+ by available memory.
+
+* Number of parameters in a macro definition and arguments in a macro call.
+
+ We allow ``USHRT_MAX``, which is no smaller than 65,535. The minimum
+ required by the standard is 127.
+
+* Number of characters on a logical source line.
+
+ The C standard requires a minimum of 4096 be permitted. CPP places
+ no limits on this, but you may get incorrect column numbers reported in
+ diagnostics for lines longer than 65,535 characters.
+
+* Maximum size of a source file.
+
+ The standard does not specify any lower limit on the maximum size of a
+ source file. GNU cpp maps files into memory, so it is limited by the
+ available address space. This is generally at least two gigabytes.
+ Depending on the operating system, the size of physical memory may or
+ may not be a limitation.
\ No newline at end of file
diff --git a/gcc/doc/cpp/index.rst b/gcc/doc/cpp/index.rst
new file mode 100644
index 00000000000..6896a4c8f26
--- /dev/null
+++ b/gcc/doc/cpp/index.rst
@@ -0,0 +1,34 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+Welcome to cpp documentation!
+===============================
+
+The C preprocessor implements the macro language used to transform C,
+C++, and Objective-C programs before they are compiled. It can also be
+useful on its own.
+
+Contents:
+
+.. toctree::
+ :maxdepth: 1
+
+ copyright
+ overview
+ header-files
+ macros
+ conditionals
+ diagnostics
+ line-control
+ pragmas
+ other-directives
+ preprocessor-output
+ traditional-mode
+ implementation-details
+ invocation
+ environment-variables
+ gnu-free-documentation-license
+
+ option-index
\ No newline at end of file
diff --git a/gcc/doc/cpp/initial-processing.rst b/gcc/doc/cpp/initial-processing.rst
new file mode 100644
index 00000000000..06e0532abf1
--- /dev/null
+++ b/gcc/doc/cpp/initial-processing.rst
@@ -0,0 +1,174 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _initial-processing:
+
+Initial processing
+******************
+
+The preprocessor performs a series of textual transformations on its
+input. These happen before all other processing. Conceptually, they
+happen in a rigid order, and the entire file is run through each
+transformation before the next one begins. CPP actually does them
+all at once, for performance reasons. These transformations correspond
+roughly to the first three 'phases of translation' described in the C
+standard.
+
+*
+ .. index:: line endings
+
+ The input file is read into memory and broken into lines.
+
+ Different systems use different conventions to indicate the end of a
+ line. GCC accepts the ASCII control sequences LF, CR
+ LF and CR as end-of-line markers. These are the canonical
+ sequences used by Unix, DOS and VMS, and the classic Mac OS (before
+ OSX) respectively. You may therefore safely copy source code written
+ on any of those systems to a different one and use it without
+ conversion. (GCC may lose track of the current line number if a file
+ doesn't consistently use one convention, as sometimes happens when it
+ is edited on computers with different conventions that share a network
+ file system.)
+
+ If the last line of any input file lacks an end-of-line marker, the end
+ of the file is considered to implicitly supply one. The C standard says
+ that this condition provokes undefined behavior, so GCC will emit a
+ warning message.
+
+*
+ .. index:: trigraphs
+
+ .. _trigraphs:
+
+ If trigraphs are enabled, they are replaced by their
+ corresponding single characters. By default GCC ignores trigraphs,
+ but if you request a strictly conforming mode with the :option:`-std`
+ option, or you specify the :option:`-trigraphs` option, then it
+ converts them.
+
+ These are nine three-character sequences, all starting with :samp:`??`,
+ that are defined by ISO C to stand for single characters. They permit
+ obsolete systems that lack some of C's punctuation to use C. For
+ example, :samp:`??/` stands for :samp:`\\`, so ``'??/n'`` is a character
+ constant for a newline.
+
+ Trigraphs are not popular and many compilers implement them
+ incorrectly. Portable code should not rely on trigraphs being either
+ converted or ignored. With :option:`-Wtrigraphs` GCC will warn you
+ when a trigraph may change the meaning of your program if it were
+ converted. See :ref:`wtrigraphs`.
+
+ In a string constant, you can prevent a sequence of question marks
+ from being confused with a trigraph by inserting a backslash between
+ the question marks, or by separating the string literal at the
+ trigraph and making use of string literal concatenation. ``"(??\?)"``
+ is the string :samp:`(???)`, not :samp:`(?]`. Traditional C compilers
+ do not recognize these idioms.
+
+ The nine trigraphs and their replacements are
+
+ .. code-block::
+
+ Trigraph: ??( ??) ??< ??> ??= ??/ ??' ??! ??-
+ Replacement: [ ] { } # \ ^ | ~
+
+*
+ .. index:: continued lines
+
+ .. index:: backslash-newline
+
+ Continued lines are merged into one long line.
+
+ A continued line is a line which ends with a backslash, :samp:`\\`. The
+ backslash is removed and the following line is joined with the current
+ one. No space is inserted, so you may split a line anywhere, even in
+ the middle of a word. (It is generally more readable to split lines
+ only at white space.)
+
+ The trailing backslash on a continued line is commonly referred to as a
+ :dfn:`backslash-newline`.
+
+ If there is white space between a backslash and the end of a line, that
+ is still a continued line. However, as this is usually the result of an
+ editing mistake, and many compilers will not accept it as a continued
+ line, GCC will warn you about it.
+
+*
+ .. index:: comments
+
+ .. index:: line comments
+
+ .. index:: block comments
+
+ All comments are replaced with single spaces.
+
+ There are two kinds of comments. :dfn:`Block comments` begin with
+ :samp:`/*` and continue until the next :samp:`*/`. Block comments do not
+ nest:
+
+ .. code-block:: c++
+
+ /* this is /* one comment */ text outside comment
+
+ :dfn:`Line comments` begin with :samp:`//` and continue to the end of the
+ current line. Line comments do not nest either, but it does not matter,
+ because they would end in the same place anyway.
+
+ .. code-block:: c++
+
+ // this is // one comment
+ text outside comment
+
+It is safe to put line comments inside block comments, or vice versa.
+
+.. code-block:: c++
+
+ /* block comment
+ // contains line comment
+ yet more comment
+ */ outside comment
+
+ // line comment /* contains block comment */
+
+But beware of commenting out one end of a block comment with a line
+comment.
+
+.. code-block::
+
+ // l.c. /* block comment begins
+ oops! this isn't a comment anymore */
+
+Comments are not recognized within string literals.
+``"/* blah */"`` is the string constant :samp:`/\* blah \*/`, not
+an empty string.
+
+Line comments are not in the 1989 edition of the C standard, but they
+are recognized by GCC as an extension. In C++ and in the 1999 edition
+of the C standard, they are an official part of the language.
+
+Since these transformations happen before all other processing, you can
+split a line mechanically with backslash-newline anywhere. You can
+comment out the end of a line. You can continue a line comment onto the
+next line with backslash-newline. You can even split :samp:`/*`,
+:samp:`*/`, and :samp:`//` onto multiple lines with backslash-newline.
+For example:
+
+.. code-block::
+
+ /\
+ *
+ */ # /*
+ */ defi\
+ ne FO\
+ O 10\
+ 20
+
+is equivalent to ``#define FOO 1020``. All these tricks are
+extremely confusing and should not be used in code intended to be
+readable.
+
+There is no way to prevent a backslash at the end of a line from being
+interpreted as a backslash-newline. This cannot affect any correct
+program, however.
\ No newline at end of file
diff --git a/gcc/doc/cpp/invocation.rst b/gcc/doc/cpp/invocation.rst
new file mode 100644
index 00000000000..ce6400af8b0
--- /dev/null
+++ b/gcc/doc/cpp/invocation.rst
@@ -0,0 +1,85 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _invocation:
+
+Invocation
+----------
+
+.. index:: invocation
+
+.. index:: command line
+
+Most often when you use the C preprocessor you do not have to invoke it
+explicitly: the C compiler does so automatically. However, the
+preprocessor is sometimes useful on its own. You can invoke the
+preprocessor either with the :command:`cpp` command, or via :command:`gcc -E`.
+In GCC, the preprocessor is actually integrated with the compiler
+rather than a separate program, and both of these commands invoke
+GCC and tell it to stop after the preprocessing phase.
+
+The :command:`cpp` options listed here are also accepted by
+:command:`gcc` and have the same meaning. Likewise the :command:`cpp`
+command accepts all the usual :command:`gcc` driver options, although those
+pertaining to compilation phases after preprocessing are ignored.
+
+Only options specific to preprocessing behavior are documented here.
+Refer to the GCC manual for full documentation of other driver options.
+
+.. only:: man
+
+ Synopsis
+ ^^^^^^^^
+
+ cpp [ :option:`-D`:samp:`{macro}` [= :samp:`{defn}` ]...] [ :option:`-U`:samp:`{macro}` ]
+ [ :option:`-I`:samp:`{dir}`...] [ :option:`-iquote`:samp:`{dir}`...]
+ [ :option:`-M` | :option:`-MM` ] [ :option:`-MG` ] [ :option:`-MF` :samp:`{filename}` ]
+ [ :option:`-MP` ] [ :option:`-MQ` :samp:`{target}`...]
+ [ :option:`-MT` :samp:`{target}`...]
+ :samp:`{infile}` [[ :option:`-o` ] :samp:`{outfile}` ]
+
+ Only the most useful options are given above; see below for a more
+ complete list of preprocessor-specific options.
+ In addition, :command:`cpp` accepts most :command:`gcc` driver options, which
+ are not listed here. Refer to the GCC documentation for details.
+
+Options
+^^^^^^^
+
+The :command:`cpp` command expects two file names as arguments, :samp:`{infile}` and
+:samp:`{outfile}`. The preprocessor reads :samp:`{infile}` together with any
+other files it specifies with :samp:`#include`. All the output generated
+by the combined input files is written in :samp:`{outfile}`.
+
+Either :samp:`{infile}` or :samp:`{outfile}` may be :option:`-`, which as
+:samp:`{infile}` means to read from standard input and as :samp:`{outfile}`
+means to write to standard output. If either file is omitted, it
+means the same as if :option:`-` had been specified for that file.
+You can also use the :option:`-o` :samp:`{outfile}` option to specify the
+output file.
+
+Unless otherwise noted, or the option ends in :samp:`=`, all options
+which take an argument may have that argument appear either immediately
+after the option, or with a space between option and argument:
+:option:`-Ifoo` and :option:`-I foo` have the same effect.
+
+.. index:: grouping options
+
+.. index:: options, grouping
+
+Many options have multi-letter names; therefore multiple single-letter
+options may *not* be grouped: :option:`-dM` is very different from
+:samp:`-d -M`.
+
+.. index:: options
+
+.. include:: ../../../doc/cppopts.rst
+
+
+.. include:: ../../../doc/cppdiropts.rst
+
+.. only:: man
+
+ .. include:: ../../../doc/copyright.rst
\ No newline at end of file
diff --git a/gcc/doc/cpp/line-control.rst b/gcc/doc/cpp/line-control.rst
new file mode 100644
index 00000000000..dcd297391e2
--- /dev/null
+++ b/gcc/doc/cpp/line-control.rst
@@ -0,0 +1,55 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _line-control:
+
+Line Control
+------------
+
+.. index:: line control
+
+The C preprocessor informs the C compiler of the location in your source
+code where each token came from. Presently, this is just the file name
+and line number. All the tokens resulting from macro expansion are
+reported as having appeared on the line of the source file where the
+outermost macro was used. We intend to be more accurate in the future.
+
+If you write a program which generates source code, such as the
+:command:`bison` parser generator, you may want to adjust the preprocessor's
+notion of the current file name and line number by hand. Parts of the
+output from :command:`bison` are generated from scratch, other parts come
+from a standard parser file. The rest are copied verbatim from
+:command:`bison`'s input. You would like compiler error messages and
+symbolic debuggers to be able to refer to ``bison`` 's input file.
+
+.. index:: #line
+
+:command:`bison` or any such program can arrange this by writing
+:samp:`#line` directives into the output file. :samp:`#line` is a
+directive that specifies the original line number and source file name
+for subsequent input in the current preprocessor input file.
+:samp:`#line` has three variants:
+
+:samp:`#line {linenum}`
+ :samp:`{linenum}` is a non-negative decimal integer constant. It specifies
+ the line number which should be reported for the following line of
+ input. Subsequent lines are counted from :samp:`{linenum}`.
+
+:samp:`#line {linenum}{filename}`
+ :samp:`{linenum}` is the same as for the first form, and has the same
+ effect. In addition, :samp:`{filename}` is a string constant. The
+ following line and all subsequent lines are reported to come from the
+ file it specifies, until something else happens to change that.
+ :samp:`{filename}` is interpreted according to the normal rules for a string
+ constant: backslash escapes are interpreted. This is different from
+ :samp:`#include`.
+
+:samp:`#line {anything else}`
+ :samp:`{anything else}` is checked for macro calls, which are expanded.
+ The result should match one of the above two forms.
+
+:samp:`#line` directives alter the results of the ``__FILE__`` and
+``__LINE__`` predefined macros from that point on. See :ref:`standard-predefined-macros`. They do not have any effect on :samp:`#include`'s
+idea of the directory containing the current file.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros.rst b/gcc/doc/cpp/macros.rst
new file mode 100644
index 00000000000..ba259608a1d
--- /dev/null
+++ b/gcc/doc/cpp/macros.rst
@@ -0,0 +1,37 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _macros:
+
+Macros
+------
+
+A :dfn:`macro` is a fragment of code which has been given a name.
+Whenever the name is used, it is replaced by the contents of the macro.
+There are two kinds of macros. They differ mostly in what they look
+like when they are used. :dfn:`Object-like` macros resemble data objects
+when used, :dfn:`function-like` macros resemble function calls.
+
+You may define any valid identifier as a macro, even if it is a C
+keyword. The preprocessor does not know anything about keywords. This
+can be useful if you wish to hide a keyword such as ``const`` from an
+older compiler that does not understand it. However, the preprocessor
+operator ``defined`` (see :ref:`defined`) can never be defined as a
+macro, and C++'s named operators (see :ref:`c++-named-operators`) cannot be
+macros when you are compiling C++.
+
+.. toctree::
+ :maxdepth: 2
+
+ macros/object-like-macros
+ macros/function-like-macros
+ macros/macro-arguments
+ macros/stringizing
+ macros/concatenation
+ macros/variadic-macros
+ macros/predefined-macros
+ macros/undefining-and-redefining-macros
+ macros/directives-within-macro-arguments
+ macros/macro-pitfalls
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/concatenation.rst b/gcc/doc/cpp/macros/concatenation.rst
new file mode 100644
index 00000000000..1ba6cde247a
--- /dev/null
+++ b/gcc/doc/cpp/macros/concatenation.rst
@@ -0,0 +1,91 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _concatenation:
+
+Concatenation
+*************
+
+.. index:: concatenation
+
+.. index:: token pasting
+
+.. index:: token concatenation
+
+.. index:: ## operator
+
+It is often useful to merge two tokens into one while expanding macros.
+This is called :dfn:`token pasting` or :dfn:`token concatenation`. The
+:samp:`##` preprocessing operator performs token pasting. When a macro
+is expanded, the two tokens on either side of each :samp:`##` operator
+are combined into a single token, which then replaces the :samp:`##` and
+the two original tokens in the macro expansion. Usually both will be
+identifiers, or one will be an identifier and the other a preprocessing
+number. When pasted, they make a longer identifier. This isn't the
+only valid case. It is also possible to concatenate two numbers (or a
+number and a name, such as ``1.5`` and ``e3`` ) into a number.
+Also, multi-character operators such as ``+=`` can be formed by
+token pasting.
+
+However, two tokens that don't together form a valid token cannot be
+pasted together. For example, you cannot concatenate ``x`` with
+``+`` in either order. If you try, the preprocessor issues a warning
+and emits the two tokens. Whether it puts white space between the
+tokens is undefined. It is common to find unnecessary uses of :samp:`##`
+in complex macros. If you get this warning, it is likely that you can
+simply remove the :samp:`##`.
+
+Both the tokens combined by :samp:`##` could come from the macro body,
+but you could just as well write them as one token in the first place.
+Token pasting is most useful when one or both of the tokens comes from a
+macro argument. If either of the tokens next to an :samp:`##` is a
+parameter name, it is replaced by its actual argument before :samp:`##`
+executes. As with stringizing, the actual argument is not
+macro-expanded first. If the argument is empty, that :samp:`##` has no
+effect.
+
+Keep in mind that the C preprocessor converts comments to whitespace
+before macros are even considered. Therefore, you cannot create a
+comment by concatenating :samp:`/` and :samp:`*`. You can put as much
+whitespace between :samp:`##` and its operands as you like, including
+comments, and you can put comments in arguments that will be
+concatenated. However, it is an error if :samp:`##` appears at either
+end of a macro body.
+
+Consider a C program that interprets named commands. There probably
+needs to be a table of commands, perhaps an array of structures declared
+as follows:
+
+.. code-block:: c++
+
+ struct command
+ {
+ char *name;
+ void (*function) (void);
+ };
+
+ struct command commands[] =
+ {
+ { "quit", quit_command },
+ { "help", help_command },
+ ...
+ };
+
+It would be cleaner not to have to give each command name twice, once in
+the string constant and once in the function name. A macro which takes the
+name of a command as an argument can make this unnecessary. The string
+constant can be created with stringizing, and the function name by
+concatenating the argument with :samp:`_command`. Here is how it is done:
+
+.. code-block:: c++
+
+ #define COMMAND(NAME) { #NAME, NAME ## _command }
+
+ struct command commands[] =
+ {
+ COMMAND (quit),
+ COMMAND (help),
+ ...
+ };
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/directives-within-macro-arguments.rst b/gcc/doc/cpp/macros/directives-within-macro-arguments.rst
new file mode 100644
index 00000000000..5c8f1c6dfcd
--- /dev/null
+++ b/gcc/doc/cpp/macros/directives-within-macro-arguments.rst
@@ -0,0 +1,39 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _directives-within-macro-arguments:
+
+Directives Within Macro Arguments
+*********************************
+
+.. index:: macro arguments and directives
+
+Occasionally it is convenient to use preprocessor directives within
+the arguments of a macro. The C and C++ standards declare that
+behavior in these cases is undefined. GNU CPP
+processes arbitrary directives within macro arguments in
+exactly the same way as it would have processed the directive were the
+function-like macro invocation not present.
+
+If, within a macro invocation, that macro is redefined, then the new
+definition takes effect in time for argument pre-expansion, but the
+original definition is still used for argument replacement. Here is a
+pathological example:
+
+.. code-block:: c++
+
+ #define f(x) x x
+ f (1
+ #undef f
+ #define f 2
+ f)
+
+which expands to
+
+.. code-block:: c++
+
+ 1 2 1 2
+
+with the semantics described above.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/function-like-macros.rst b/gcc/doc/cpp/macros/function-like-macros.rst
new file mode 100644
index 00000000000..12273bda869
--- /dev/null
+++ b/gcc/doc/cpp/macros/function-like-macros.rst
@@ -0,0 +1,55 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _function-like-macros:
+
+Function-like Macros
+********************
+
+.. index:: function-like macros
+
+You can also define macros whose use looks like a function call. These
+are called :dfn:`function-like macros`. To define a function-like macro,
+you use the same :samp:`#define` directive, but you put a pair of
+parentheses immediately after the macro name. For example,
+
+.. code-block::
+
+ #define lang_init() c_init()
+ lang_init()
+ → c_init()
+
+A function-like macro is only expanded if its name appears with a pair
+of parentheses after it. If you write just the name, it is left alone.
+This can be useful when you have a function and a macro of the same
+name, and you wish to use the function sometimes.
+
+.. code-block::
+
+ extern void foo(void);
+ #define foo() /* optimized inline version */
+ ...
+ foo();
+ funcptr = foo;
+
+Here the call to ``foo()`` will use the macro, but the function
+pointer will get the address of the real function. If the macro were to
+be expanded, it would cause a syntax error.
+
+If you put spaces between the macro name and the parentheses in the
+macro definition, that does not define a function-like macro, it defines
+an object-like macro whose expansion happens to begin with a pair of
+parentheses.
+
+.. code-block::
+
+ #define lang_init () c_init()
+ lang_init()
+ → () c_init()()
+
+The first two pairs of parentheses in this expansion come from the
+macro. The third is the pair that was originally after the macro
+invocation. Since ``lang_init`` is an object-like macro, it does not
+consume those parentheses.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/macro-arguments.rst b/gcc/doc/cpp/macros/macro-arguments.rst
new file mode 100644
index 00000000000..c65dfa1e12a
--- /dev/null
+++ b/gcc/doc/cpp/macros/macro-arguments.rst
@@ -0,0 +1,116 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _macro-arguments:
+
+Macro Arguments
+***************
+
+.. index:: arguments
+
+.. index:: macros with arguments
+
+.. index:: arguments in macro definitions
+
+Function-like macros can take :dfn:`arguments`, just like true functions.
+To define a macro that uses arguments, you insert :dfn:`parameters`
+between the pair of parentheses in the macro definition that make the
+macro function-like. The parameters must be valid C identifiers,
+separated by commas and optionally whitespace.
+
+To invoke a macro that takes arguments, you write the name of the macro
+followed by a list of :dfn:`actual arguments` in parentheses, separated
+by commas. The invocation of the macro need not be restricted to a
+single logical line---it can cross as many lines in the source file as
+you wish. The number of arguments you give must match the number of
+parameters in the macro definition. When the macro is expanded, each
+use of a parameter in its body is replaced by the tokens of the
+corresponding argument. (You need not use all of the parameters in the
+macro body.)
+
+As an example, here is a macro that computes the minimum of two numeric
+values, as it is defined in many C programs, and some uses.
+
+.. code-block::
+
+ #define min(X, Y) ((X) < (Y) ? (X) : (Y))
+ x = min(a, b); → x = ((a) < (b) ? (a) : (b));
+ y = min(1, 2); → y = ((1) < (2) ? (1) : (2));
+ z = min(a + 28, *p); → z = ((a + 28) < (*p) ? (a + 28) : (*p));
+
+(In this small example you can already see several of the dangers of
+macro arguments. See :ref:`macro-pitfalls`, for detailed explanations.)
+
+Leading and trailing whitespace in each argument is dropped, and all
+whitespace between the tokens of an argument is reduced to a single
+space. Parentheses within each argument must balance; a comma within
+such parentheses does not end the argument. However, there is no
+requirement for square brackets or braces to balance, and they do not
+prevent a comma from separating arguments. Thus,
+
+.. code-block:: c++
+
+ macro (array[x = y, x + 1])
+
+passes two arguments to ``macro`` : ``array[x = y`` and ``x +
+1]``. If you want to supply ``array[x = y, x + 1]`` as an argument,
+you can write it as ``array[(x = y, x + 1)]``, which is equivalent C
+code.
+
+All arguments to a macro are completely macro-expanded before they are
+substituted into the macro body. After substitution, the complete text
+is scanned again for macros to expand, including the arguments. This rule
+may seem strange, but it is carefully designed so you need not worry
+about whether any function call is actually a macro invocation. You can
+run into trouble if you try to be too clever, though. See :ref:`argument-prescan`, for detailed discussion.
+
+For example, ``min (min (a, b), c)`` is first expanded to
+
+.. code-block:: c++
+
+ min (((a) < (b) ? (a) : (b)), (c))
+
+and then to
+
+.. code-block:: c++
+
+ ((((a) < (b) ? (a) : (b))) < (c)
+ ? (((a) < (b) ? (a) : (b)))
+ : (c))
+
+(Line breaks shown here for clarity would not actually be generated.)
+
+.. index:: empty macro arguments
+
+You can leave macro arguments empty; this is not an error to the
+preprocessor (but many macros will then expand to invalid code).
+You cannot leave out arguments entirely; if a macro takes two arguments,
+there must be exactly one comma at the top level of its argument list.
+Here are some silly examples using ``min`` :
+
+.. code-block::
+
+ min(, b) → (( ) < (b) ? ( ) : (b))
+ min(a, ) → ((a ) < ( ) ? (a ) : ( ))
+ min(,) → (( ) < ( ) ? ( ) : ( ))
+ min((,),) → (((,)) < ( ) ? ((,)) : ( ))
+
+ min() error macro "min" requires 2 arguments, but only 1 given
+ min(,,) error macro "min" passed 3 arguments, but takes just 2
+
+Whitespace is not a preprocessing token, so if a macro ``foo`` takes
+one argument, ``foo ()`` and ``foo ( )`` both supply it an
+empty argument. Previous GNU preprocessor implementations and
+documentation were incorrect on this point, insisting that a
+function-like macro that takes a single argument be passed a space if an
+empty argument was required.
+
+Macro parameters appearing inside string literals are not replaced by
+their corresponding actual arguments.
+
+.. code-block::
+
+ #define foo(x) x, "x"
+ foo(bar) → bar, "x"
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/macro-pitfalls.rst b/gcc/doc/cpp/macros/macro-pitfalls.rst
new file mode 100644
index 00000000000..ff3dbbd8610
--- /dev/null
+++ b/gcc/doc/cpp/macros/macro-pitfalls.rst
@@ -0,0 +1,457 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _macro-pitfalls:
+
+Macro Pitfalls
+**************
+
+.. index:: problems with macros
+
+.. index:: pitfalls of macros
+
+In this section we describe some special rules that apply to macros and
+macro expansion, and point out certain cases in which the rules have
+counter-intuitive consequences that you must watch out for.
+
+.. toctree::
+ :maxdepth: 2
+
+
+.. _misnesting:
+
+Misnesting
+^^^^^^^^^^
+
+When a macro is called with arguments, the arguments are substituted
+into the macro body and the result is checked, together with the rest of
+the input file, for more macro calls. It is possible to piece together
+a macro call coming partially from the macro body and partially from the
+arguments. For example,
+
+.. code-block::
+
+ #define twice(x) (2*(x))
+ #define call_with_1(x) x(1)
+ call_with_1 (twice)
+ → twice(1)
+ → (2*(1))
+
+Macro definitions do not have to have balanced parentheses. By writing
+an unbalanced open parenthesis in a macro body, it is possible to create
+a macro call that begins inside the macro body but ends outside of it.
+For example,
+
+.. code-block::
+
+ #define strange(file) fprintf (file, "%s %d",
+ ...
+ strange(stderr) p, 35)
+ → fprintf (stderr, "%s %d", p, 35)
+
+The ability to piece together a macro call can be useful, but the use of
+unbalanced open parentheses in a macro body is just confusing, and
+should be avoided.
+
+.. _operator-precedence-problems:
+
+Operator Precedence Problems
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: parentheses in macro bodies
+
+You may have noticed that in most of the macro definition examples shown
+above, each occurrence of a macro argument name had parentheses around
+it. In addition, another pair of parentheses usually surround the
+entire macro definition. Here is why it is best to write macros that
+way.
+
+Suppose you define a macro as follows,
+
+.. code-block:: c++
+
+ #define ceil_div(x, y) (x + y - 1) / y
+
+whose purpose is to divide, rounding up. (One use for this operation is
+to compute how many ``int`` objects are needed to hold a certain
+number of ``char`` objects.) Then suppose it is used as follows:
+
+.. code-block::
+
+ a = ceil_div (b & c, sizeof (int));
+ → a = (b & c + sizeof (int) - 1) / sizeof (int);
+
+This does not do what is intended. The operator-precedence rules of
+C make it equivalent to this:
+
+.. code-block:: c++
+
+ a = (b & (c + sizeof (int) - 1)) / sizeof (int);
+
+What we want is this:
+
+.. code-block:: c++
+
+ a = ((b & c) + sizeof (int) - 1)) / sizeof (int);
+
+Defining the macro as
+
+.. code-block:: c++
+
+ #define ceil_div(x, y) ((x) + (y) - 1) / (y)
+
+provides the desired result.
+
+Unintended grouping can result in another way. Consider ``sizeof
+ceil_div(1, 2)``. That has the appearance of a C expression that would
+compute the size of the type of ``ceil_div (1, 2)``, but in fact it
+means something very different. Here is what it expands to:
+
+.. code-block:: c++
+
+ sizeof ((1) + (2) - 1) / (2)
+
+This would take the size of an integer and divide it by two. The
+precedence rules have put the division outside the ``sizeof`` when it
+was intended to be inside.
+
+Parentheses around the entire macro definition prevent such problems.
+Here, then, is the recommended way to define ``ceil_div`` :
+
+.. code-block:: c++
+
+ #define ceil_div(x, y) (((x) + (y) - 1) / (y))
+
+.. _swallowing-the-semicolon:
+
+Swallowing the Semicolon
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: semicolons (after macro calls)
+
+Often it is desirable to define a macro that expands into a compound
+statement. Consider, for example, the following macro, that advances a
+pointer (the argument ``p`` says where to find it) across whitespace
+characters:
+
+.. code-block:: c++
+
+ #define SKIP_SPACES(p, limit) \
+ { char *lim = (limit); \
+ while (p < lim) { \
+ if (*p++ != ' ') { \
+ p--; break; }}}
+
+Here backslash-newline is used to split the macro definition, which must
+be a single logical line, so that it resembles the way such code would
+be laid out if not part of a macro definition.
+
+A call to this macro might be ``SKIP_SPACES (p, lim)``. Strictly
+speaking, the call expands to a compound statement, which is a complete
+statement with no need for a semicolon to end it. However, since it
+looks like a function call, it minimizes confusion if you can use it
+like a function call, writing a semicolon afterward, as in
+``SKIP_SPACES (p, lim);``
+
+This can cause trouble before ``else`` statements, because the
+semicolon is actually a null statement. Suppose you write
+
+.. code-block:: c++
+
+ if (*p != 0)
+ SKIP_SPACES (p, lim);
+ else ...
+
+The presence of two statements---the compound statement and a null
+statement---in between the ``if`` condition and the ``else``
+makes invalid C code.
+
+The definition of the macro ``SKIP_SPACES`` can be altered to solve
+this problem, using a ``do ... while`` statement. Here is how:
+
+.. code-block:: c++
+
+ #define SKIP_SPACES(p, limit) \
+ do { char *lim = (limit); \
+ while (p < lim) { \
+ if (*p++ != ' ') { \
+ p--; break; }}} \
+ while (0)
+
+Now ``SKIP_SPACES (p, lim);`` expands into
+
+.. code-block:: c++
+
+ do {...} while (0);
+
+which is one statement. The loop executes exactly once; most compilers
+generate no extra code for it.
+
+.. _duplication-of-side-effects:
+
+Duplication of Side Effects
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: side effects (in macro arguments)
+
+.. index:: unsafe macros
+
+Many C programs define a macro ``min``, for 'minimum', like this:
+
+.. code-block:: c++
+
+ #define min(X, Y) ((X) < (Y) ? (X) : (Y))
+
+When you use this macro with an argument containing a side effect,
+as shown here,
+
+.. code-block:: c++
+
+ next = min (x + y, foo (z));
+
+it expands as follows:
+
+.. code-block:: c++
+
+ next = ((x + y) < (foo (z)) ? (x + y) : (foo (z)));
+
+where ``x + y`` has been substituted for ``X`` and ``foo (z)``
+for ``Y``.
+
+The function ``foo`` is used only once in the statement as it appears
+in the program, but the expression ``foo (z)`` has been substituted
+twice into the macro expansion. As a result, ``foo`` might be called
+two times when the statement is executed. If it has side effects or if
+it takes a long time to compute, the results might not be what you
+intended. We say that ``min`` is an :dfn:`unsafe` macro.
+
+The best solution to this problem is to define ``min`` in a way that
+computes the value of ``foo (z)`` only once. The C language offers
+no standard way to do this, but it can be done with GNU extensions as
+follows:
+
+.. code-block:: c++
+
+ #define min(X, Y) \
+ ({ typeof (X) x_ = (X); \
+ typeof (Y) y_ = (Y); \
+ (x_ < y_) ? x_ : y_; })
+
+The :samp:`({ ... })` notation produces a compound statement that
+acts as an expression. Its value is the value of its last statement.
+This permits us to define local variables and assign each argument to
+one. The local variables have underscores after their names to reduce
+the risk of conflict with an identifier of wider scope (it is impossible
+to avoid this entirely). Now each argument is evaluated exactly once.
+
+If you do not wish to use GNU C extensions, the only solution is to be
+careful when *using* the macro ``min``. For example, you can
+calculate the value of ``foo (z)``, save it in a variable, and use
+that variable in ``min`` :
+
+.. code-block:: c++
+
+ #define min(X, Y) ((X) < (Y) ? (X) : (Y))
+ ...
+ {
+ int tem = foo (z);
+ next = min (x + y, tem);
+ }
+
+(where we assume that ``foo`` returns type ``int`` ).
+
+.. _self-referential-macros:
+
+Self-Referential Macros
+^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: self-reference
+
+A :dfn:`self-referential` macro is one whose name appears in its
+definition. Recall that all macro definitions are rescanned for more
+macros to replace. If the self-reference were considered a use of the
+macro, it would produce an infinitely large expansion. To prevent this,
+the self-reference is not considered a macro call. It is passed into
+the preprocessor output unchanged. Consider an example:
+
+.. code-block:: c++
+
+ #define foo (4 + foo)
+
+where ``foo`` is also a variable in your program.
+
+Following the ordinary rules, each reference to ``foo`` will expand
+into ``(4 + foo)`` ; then this will be rescanned and will expand into
+``(4 + (4 + foo))`` ; and so on until the computer runs out of memory.
+
+The self-reference rule cuts this process short after one step, at
+``(4 + foo)``. Therefore, this macro definition has the possibly
+useful effect of causing the program to add 4 to the value of ``foo``
+wherever ``foo`` is referred to.
+
+In most cases, it is a bad idea to take advantage of this feature. A
+person reading the program who sees that ``foo`` is a variable will
+not expect that it is a macro as well. The reader will come across the
+identifier ``foo`` in the program and think its value should be that
+of the variable ``foo``, whereas in fact the value is four greater.
+
+One common, useful use of self-reference is to create a macro which
+expands to itself. If you write
+
+.. code-block:: c++
+
+ #define EPERM EPERM
+
+then the macro ``EPERM`` expands to ``EPERM``. Effectively, it is
+left alone by the preprocessor whenever it's used in running text. You
+can tell that it's a macro with :samp:`#ifdef`. You might do this if you
+want to define numeric constants with an ``enum``, but have
+:samp:`#ifdef` be true for each constant.
+
+If a macro ``x`` expands to use a macro ``y``, and the expansion of
+``y`` refers to the macro ``x``, that is an :dfn:`indirect
+self-reference` of ``x``. ``x`` is not expanded in this case
+either. Thus, if we have
+
+.. code-block:: c++
+
+ #define x (4 + y)
+ #define y (2 * x)
+
+then ``x`` and ``y`` expand as follows:
+
+.. code-block::
+
+ x → (4 + y)
+ → (4 + (2 * x))
+
+ y → (2 * x)
+ → (2 * (4 + y))
+
+Each macro is expanded when it appears in the definition of the other
+macro, but not when it indirectly appears in its own definition.
+
+.. _argument-prescan:
+
+Argument Prescan
+^^^^^^^^^^^^^^^^
+
+.. index:: expansion of arguments
+
+.. index:: macro argument expansion
+
+.. index:: prescan of macro arguments
+
+Macro arguments are completely macro-expanded before they are
+substituted into a macro body, unless they are stringized or pasted
+with other tokens. After substitution, the entire macro body, including
+the substituted arguments, is scanned again for macros to be expanded.
+The result is that the arguments are scanned *twice* to expand
+macro calls in them.
+
+Most of the time, this has no effect. If the argument contained any
+macro calls, they are expanded during the first scan. The result
+therefore contains no macro calls, so the second scan does not change
+it. If the argument were substituted as given, with no prescan, the
+single remaining scan would find the same macro calls and produce the
+same results.
+
+You might expect the double scan to change the results when a
+self-referential macro is used in an argument of another macro
+(see :ref:`self-referential-macros`): the self-referential macro would be
+expanded once in the first scan, and a second time in the second scan.
+However, this is not what happens. The self-references that do not
+expand in the first scan are marked so that they will not expand in the
+second scan either.
+
+You might wonder, 'Why mention the prescan, if it makes no difference?
+And why not skip it and make the preprocessor faster?' The answer is
+that the prescan does make a difference in three special cases:
+
+* Nested calls to a macro.
+
+ We say that :dfn:`nested` calls to a macro occur when a macro's argument
+ contains a call to that very macro. For example, if ``f`` is a macro
+ that expects one argument, ``f (f (1))`` is a nested pair of calls to
+ ``f``. The desired expansion is made by expanding ``f (1)`` and
+ substituting that into the definition of ``f``. The prescan causes
+ the expected result to happen. Without the prescan, ``f (1)`` itself
+ would be substituted as an argument, and the inner use of ``f`` would
+ appear during the main scan as an indirect self-reference and would not
+ be expanded.
+
+* Macros that call other macros that stringize or concatenate.
+
+ If an argument is stringized or concatenated, the prescan does not
+ occur. If you *want* to expand a macro, then stringize or
+ concatenate its expansion, you can do that by causing one macro to call
+ another macro that does the stringizing or concatenation. For
+ instance, if you have
+
+ .. code-block:: c++
+
+ #define AFTERX(x) X_ ## x
+ #define XAFTERX(x) AFTERX(x)
+ #define TABLESIZE 1024
+ #define BUFSIZE TABLESIZE
+
+ then ``AFTERX(BUFSIZE)`` expands to ``X_BUFSIZE``, and
+ ``XAFTERX(BUFSIZE)`` expands to ``X_1024``. (Not to
+ ``X_TABLESIZE``. Prescan always does a complete expansion.)
+
+* Macros used in arguments, whose expansions contain unshielded commas.
+
+ This can cause a macro expanded on the second scan to be called with the
+ wrong number of arguments. Here is an example:
+
+ .. code-block:: c++
+
+ #define foo a,b
+ #define bar(x) lose(x)
+ #define lose(x) (1 + (x))
+
+ We would like ``bar(foo)`` to turn into ``(1 + (foo))``, which
+ would then turn into ``(1 + (a,b))``. Instead, ``bar(foo)``
+ expands into ``lose(a,b)``, and you get an error because ``lose``
+ requires a single argument. In this case, the problem is easily solved
+ by the same parentheses that ought to be used to prevent misnesting of
+ arithmetic operations:
+
+ .. code-block::
+
+ #define foo (a,b)
+ or#define bar(x) lose((x))
+
+ The extra pair of parentheses prevents the comma in ``foo`` 's
+ definition from being interpreted as an argument separator.
+
+.. _newlines-in-arguments:
+
+Newlines in Arguments
+^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: newlines in macro arguments
+
+The invocation of a function-like macro can extend over many logical
+lines. However, in the present implementation, the entire expansion
+comes out on one line. Thus line numbers emitted by the compiler or
+debugger refer to the line the invocation started on, which might be
+different to the line containing the argument causing the problem.
+
+Here is an example illustrating this:
+
+.. code-block:: c++
+
+ #define ignore_second_arg(a,b,c) a; c
+
+ ignore_second_arg (foo (),
+ ignored (),
+ syntax error);
+
+The syntax error triggered by the tokens ``syntax error`` results in
+an error message citing line three---the line of ignore_second_arg---
+even though the problematic code comes from line five.
+
+We consider this a bug, and intend to fix it in the near future.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/object-like-macros.rst b/gcc/doc/cpp/macros/object-like-macros.rst
new file mode 100644
index 00000000000..2ee47f288a3
--- /dev/null
+++ b/gcc/doc/cpp/macros/object-like-macros.rst
@@ -0,0 +1,130 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _object-like-macros:
+
+Object-like Macros
+******************
+
+.. index:: object-like macro
+
+.. index:: symbolic constants
+
+.. index:: manifest constants
+
+An :dfn:`object-like macro` is a simple identifier which will be replaced
+by a code fragment. It is called object-like because it looks like a
+data object in code that uses it. They are most commonly used to give
+symbolic names to numeric constants.
+
+.. index:: #define
+
+You create macros with the :samp:`#define` directive. :samp:`#define` is
+followed by the name of the macro and then the token sequence it should
+be an abbreviation for, which is variously referred to as the macro's
+:dfn:`body`, :dfn:`expansion` or :dfn:`replacement list`. For example,
+
+.. code-block:: c++
+
+ #define BUFFER_SIZE 1024
+
+defines a macro named ``BUFFER_SIZE`` as an abbreviation for the
+token ``1024``. If somewhere after this :samp:`#define` directive
+there comes a C statement of the form
+
+.. code-block:: c++
+
+ foo = (char *) malloc (BUFFER_SIZE);
+
+then the C preprocessor will recognize and :dfn:`expand` the macro
+``BUFFER_SIZE``. The C compiler will see the same tokens as it would
+if you had written
+
+.. code-block:: c++
+
+ foo = (char *) malloc (1024);
+
+By convention, macro names are written in uppercase. Programs are
+easier to read when it is possible to tell at a glance which names are
+macros.
+
+The macro's body ends at the end of the :samp:`#define` line. You may
+continue the definition onto multiple lines, if necessary, using
+backslash-newline. When the macro is expanded, however, it will all
+come out on one line. For example,
+
+.. code-block::
+
+ #define NUMBERS 1, \
+ 2, \
+ 3
+ int x[] = { NUMBERS };
+ → int x[] = { 1, 2, 3 };
+
+The most common visible consequence of this is surprising line numbers
+in error messages.
+
+There is no restriction on what can go in a macro body provided it
+decomposes into valid preprocessing tokens. Parentheses need not
+balance, and the body need not resemble valid C code. (If it does not,
+you may get error messages from the C compiler when you use the macro.)
+
+The C preprocessor scans your program sequentially. Macro definitions
+take effect at the place you write them. Therefore, the following input
+to the C preprocessor
+
+.. code-block:: c++
+
+ foo = X;
+ #define X 4
+ bar = X;
+
+produces
+
+.. code-block:: c++
+
+ foo = X;
+ bar = 4;
+
+When the preprocessor expands a macro name, the macro's expansion
+replaces the macro invocation, then the expansion is examined for more
+macros to expand. For example,
+
+.. code-block::
+
+ #define TABLESIZE BUFSIZE
+ #define BUFSIZE 1024
+ TABLESIZE
+ → BUFSIZE
+ → 1024
+
+``TABLESIZE`` is expanded first to produce ``BUFSIZE``, then that
+macro is expanded to produce the final result, ``1024``.
+
+Notice that ``BUFSIZE`` was not defined when ``TABLESIZE`` was
+defined. The :samp:`#define` for ``TABLESIZE`` uses exactly the
+expansion you specify---in this case, ``BUFSIZE`` ---and does not
+check to see whether it too contains macro names. Only when you
+*use* ``TABLESIZE`` is the result of its expansion scanned for
+more macro names.
+
+This makes a difference if you change the definition of ``BUFSIZE``
+at some point in the source file. ``TABLESIZE``, defined as shown,
+will always expand using the definition of ``BUFSIZE`` that is
+currently in effect:
+
+.. code-block:: c++
+
+ #define BUFSIZE 1020
+ #define TABLESIZE BUFSIZE
+ #undef BUFSIZE
+ #define BUFSIZE 37
+
+Now ``TABLESIZE`` expands (in two stages) to ``37``.
+
+If the expansion of a macro contains its own name, either directly or
+via intermediate macros, it is not expanded again when the expansion is
+examined for more macros. This prevents infinite recursion.
+See :ref:`self-referential-macros`, for the precise details.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/predefined-macros.rst b/gcc/doc/cpp/macros/predefined-macros.rst
new file mode 100644
index 00000000000..0821667d522
--- /dev/null
+++ b/gcc/doc/cpp/macros/predefined-macros.rst
@@ -0,0 +1,658 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _predefined-macros:
+
+Predefined Macros
+*****************
+
+.. index:: predefined macros
+
+Several object-like macros are predefined; you use them without
+supplying their definitions. They fall into three classes: standard,
+common, and system-specific.
+
+In C++, there is a fourth category, the named operators. They act like
+predefined macros, but you cannot undefine them.
+
+.. toctree::
+ :maxdepth: 2
+
+
+.. _standard-predefined-macros:
+
+Standard Predefined Macros
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: standard predefined macros.
+
+The standard predefined macros are specified by the relevant
+language standards, so they are available with all compilers that
+implement those standards. Older compilers may not provide all of
+them. Their names all start with double underscores.
+
+``__FILE__``
+ This macro expands to the name of the current input file, in the form of
+ a C string constant. This is the path by which the preprocessor opened
+ the file, not the short name specified in :samp:`#include` or as the
+ input file name argument. For example,
+ ``"/usr/local/include/myheader.h"`` is a possible expansion of this
+ macro.
+
+``__LINE__``
+ This macro expands to the current input line number, in the form of a
+ decimal integer constant. While we call it a predefined macro, it's
+ a pretty strange macro, since its 'definition' changes with each
+ new line of source code.
+
+ ``__FILE__`` and ``__LINE__`` are useful in generating an error
+ message to report an inconsistency detected by the program; the message
+ can state the source line at which the inconsistency was detected. For
+ example,
+
+.. code-block:: c++
+
+ fprintf (stderr, "Internal error: "
+ "negative string length "
+ "%d at %s, line %d.",
+ length, __FILE__, __LINE__);
+
+An :samp:`#include` directive changes the expansions of ``__FILE__``
+and ``__LINE__`` to correspond to the included file. At the end of
+that file, when processing resumes on the input file that contained
+the :samp:`#include` directive, the expansions of ``__FILE__`` and
+``__LINE__`` revert to the values they had before the
+:samp:`#include` (but ``__LINE__`` is then incremented by one as
+processing moves to the line after the :samp:`#include`).
+
+A :samp:`#line` directive changes ``__LINE__``, and may change
+``__FILE__`` as well. See :ref:`line-control`.
+
+C99 introduced ``__func__``, and GCC has provided ``__FUNCTION__``
+for a long time. Both of these are strings containing the name of the
+current function (there are slight semantic differences; see the GCC
+manual). Neither of them is a macro; the preprocessor does not know the
+name of the current function. They tend to be useful in conjunction
+with ``__FILE__`` and ``__LINE__``, though.
+
+``__DATE__``
+ This macro expands to a string constant that describes the date on which
+ the preprocessor is being run. The string constant contains eleven
+ characters and looks like ``"Feb 12 1996"``. If the day of the
+ month is less than 10, it is padded with a space on the left.
+
+ If GCC cannot determine the current date, it will emit a warning message
+ (once per compilation) and ``__DATE__`` will expand to
+ ``"??? ?? ????"``.
+
+``__TIME__``
+ This macro expands to a string constant that describes the time at
+ which the preprocessor is being run. The string constant contains
+ eight characters and looks like ``"23:59:01"``.
+
+ If GCC cannot determine the current time, it will emit a warning message
+ (once per compilation) and ``__TIME__`` will expand to
+ ``"??:??:??"``.
+
+``__STDC__``
+ In normal operation, this macro expands to the constant 1, to signify
+ that this compiler conforms to ISO Standard C. If GNU CPP is used with
+ a compiler other than GCC, this is not necessarily true; however, the
+ preprocessor always conforms to the standard unless the
+ :option:`-traditional-cpp` option is used.
+
+ This macro is not defined if the :option:`-traditional-cpp` option is used.
+
+ On some hosts, the system compiler uses a different convention, where
+ ``__STDC__`` is normally 0, but is 1 if the user specifies strict
+ conformance to the C Standard. CPP follows the host convention when
+ processing system header files, but when processing user files
+ ``__STDC__`` is always 1. This has been reported to cause problems;
+ for instance, some versions of Solaris provide X Windows headers that
+ expect ``__STDC__`` to be either undefined or 1. See :ref:`invocation`.
+
+``__STDC_VERSION__``
+ This macro expands to the C Standard's version number, a long integer
+ constant of the form ``yyyymmL`` where :samp:`{yyyy}` and
+ :samp:`{mm}` are the year and month of the Standard version. This signifies
+ which version of the C Standard the compiler conforms to. Like
+ ``__STDC__``, this is not necessarily accurate for the entire
+ implementation, unless GNU CPP is being used with GCC.
+
+ The value ``199409L`` signifies the 1989 C standard as amended in
+ 1994, which is the current default; the value ``199901L`` signifies
+ the 1999 revision of the C standard; the value ``201112L``
+ signifies the 2011 revision of the C standard; the value
+ ``201710L`` signifies the 2017 revision of the C standard (which is
+ otherwise identical to the 2011 version apart from correction of
+ defects). An unspecified value larger than ``201710L`` is used for
+ the experimental :option:`-std`:samp:`=c2x` and :option:`-std`:samp:`=gnu2x` modes.
+
+ This macro is not defined if the :option:`-traditional-cpp` option is
+ used, nor when compiling C++ or Objective-C.
+
+``__STDC_HOSTED__``
+ This macro is defined, with value 1, if the compiler's target is a
+ :dfn:`hosted environment`. A hosted environment has the complete
+ facilities of the standard C library available.
+
+``__cplusplus``
+ This macro is defined when the C++ compiler is in use. You can use
+ ``__cplusplus`` to test whether a header is compiled by a C compiler
+ or a C++ compiler. This macro is similar to ``__STDC_VERSION__``, in
+ that it expands to a version number. Depending on the language standard
+ selected, the value of the macro is
+ ``199711L`` for the 1998 C++ standard,
+ ``201103L`` for the 2011 C++ standard,
+ ``201402L`` for the 2014 C++ standard,
+ ``201703L`` for the 2017 C++ standard,
+ ``202002L`` for the 2020 C++ standard,
+ or an unspecified value strictly larger than ``202002L`` for the
+ experimental languages enabled by :option:`-std`:samp:`=c++23` and
+ :option:`-std`:samp:`=gnu++23`.
+
+``__OBJC__``
+ This macro is defined, with value 1, when the Objective-C compiler is in
+ use. You can use ``__OBJC__`` to test whether a header is compiled
+ by a C compiler or an Objective-C compiler.
+
+``__ASSEMBLER__``
+ This macro is defined with value 1 when preprocessing assembly
+ language.
+
+ .. _common-predefined-macros:
+
+Common Predefined Macros
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: common predefined macros
+
+The common predefined macros are GNU C extensions. They are available
+with the same meanings regardless of the machine or operating system on
+which you are using GNU C or GNU Fortran. Their names all start with
+double underscores.
+
+``__COUNTER__``
+ This macro expands to sequential integral values starting from 0. In
+ conjunction with the ``##`` operator, this provides a convenient means to
+ generate unique identifiers. Care must be taken to ensure that
+ ``__COUNTER__`` is not expanded prior to inclusion of precompiled headers
+ which use it. Otherwise, the precompiled headers will not be used.
+
+``__GFORTRAN__``
+ The GNU Fortran compiler defines this.
+
+``__GNUC__`` ``__GNUC_MINOR__`` ``__GNUC_PATCHLEVEL__``
+ These macros are defined by all GNU compilers that use the C
+ preprocessor: C, C++, Objective-C and Fortran. Their values are the major
+ version, minor version, and patch level of the compiler, as integer
+ constants. For example, GCC version :samp:`{x}`. :samp:`{y}`. :samp:`{z}`
+ defines ``__GNUC__`` to :samp:`{x}`, ``__GNUC_MINOR__`` to :samp:`{y}`,
+ and ``__GNUC_PATCHLEVEL__`` to :samp:`{z}`. These
+ macros are also defined if you invoke the preprocessor directly.
+
+ If all you need to know is whether or not your program is being compiled
+ by GCC, or a non-GCC compiler that claims to accept the GNU C dialects,
+ you can simply test ``__GNUC__``. If you need to write code
+ which depends on a specific version, you must be more careful. Each
+ time the minor version is increased, the patch level is reset to zero;
+ each time the major version is increased, the
+ minor version and patch level are reset. If you wish to use the
+ predefined macros directly in the conditional, you will need to write it
+ like this:
+
+ .. code-block:: c++
+
+ /* Test for GCC > 3.2.0 */
+ #if __GNUC__ > 3 || \
+ (__GNUC__ == 3 && (__GNUC_MINOR__ > 2 || \
+ (__GNUC_MINOR__ == 2 && \
+ __GNUC_PATCHLEVEL__ > 0))
+
+ Another approach is to use the predefined macros to
+ calculate a single number, then compare that against a threshold:
+
+ .. code-block:: c++
+
+ #define GCC_VERSION (__GNUC__ * 10000 \
+ + __GNUC_MINOR__ * 100 \
+ + __GNUC_PATCHLEVEL__)
+ ...
+ /* Test for GCC > 3.2.0 */
+ #if GCC_VERSION > 30200
+
+ Many people find this form easier to understand.
+
+``__GNUG__``
+ The GNU C++ compiler defines this. Testing it is equivalent to
+ testing ``(__GNUC__ && __cplusplus)``.
+
+``__STRICT_ANSI__``
+ GCC defines this macro if and only if the :option:`-ansi` switch, or a
+ :option:`-std` switch specifying strict conformance to some version of ISO C
+ or ISO C++, was specified when GCC was invoked. It is defined to :samp:`1`.
+ This macro exists primarily to direct GNU libc's header files to use only
+ definitions found in standard C.
+
+``__BASE_FILE__``
+ This macro expands to the name of the main input file, in the form
+ of a C string constant. This is the source file that was specified
+ on the command line of the preprocessor or C compiler.
+
+``__FILE_NAME__``
+ This macro expands to the basename of the current input file, in the
+ form of a C string constant. This is the last path component by which
+ the preprocessor opened the file. For example, processing
+ ``"/usr/local/include/myheader.h"`` would set this
+ macro to ``"myheader.h"``.
+
+``__INCLUDE_LEVEL__``
+ This macro expands to a decimal integer constant that represents the
+ depth of nesting in include files. The value of this macro is
+ incremented on every :samp:`#include` directive and decremented at the
+ end of every included file. It starts out at 0, its value within the
+ base file specified on the command line.
+
+``__ELF__``
+ This macro is defined if the target uses the ELF object format.
+
+``__VERSION__``
+ This macro expands to a string constant which describes the version of
+ the compiler in use. You should not rely on its contents having any
+ particular form, but it can be counted on to contain at least the
+ release number.
+
+``__OPTIMIZE__`` ``__OPTIMIZE_SIZE__`` ``__NO_INLINE__``
+ These macros describe the compilation mode. ``__OPTIMIZE__`` is
+ defined in all optimizing compilations. ``__OPTIMIZE_SIZE__`` is
+ defined if the compiler is optimizing for size, not speed.
+ ``__NO_INLINE__`` is defined if no functions will be inlined into
+ their callers (when not optimizing, or when inlining has been
+ specifically disabled by :option:`-fno-inline` ).
+
+ These macros cause certain GNU header files to provide optimized
+ definitions, using macros or inline functions, of system library
+ functions. You should not use these macros in any way unless you make
+ sure that programs will execute with the same effect whether or not they
+ are defined. If they are defined, their value is 1.
+
+``__GNUC_GNU_INLINE__``
+ GCC defines this macro if functions declared ``inline`` will be
+ handled in GCC's traditional gnu90 mode. Object files will contain
+ externally visible definitions of all functions declared ``inline``
+ without ``extern`` or ``static``. They will not contain any
+ definitions of any functions declared ``extern inline``.
+
+``__GNUC_STDC_INLINE__``
+ GCC defines this macro if functions declared ``inline`` will be
+ handled according to the ISO C99 or later standards. Object files will contain
+ externally visible definitions of all functions declared ``extern
+ inline``. They will not contain definitions of any functions declared
+ ``inline`` without ``extern``.
+
+ If this macro is defined, GCC supports the ``gnu_inline`` function
+ attribute as a way to always get the gnu90 behavior.
+
+``__CHAR_UNSIGNED__``
+ GCC defines this macro if and only if the data type ``char`` is
+ unsigned on the target machine. It exists to cause the standard header
+ file :samp:`limits.h` to work correctly. You should not use this macro
+ yourself; instead, refer to the standard macros defined in :samp:`limits.h`.
+
+``__WCHAR_UNSIGNED__``
+ Like ``__CHAR_UNSIGNED__``, this macro is defined if and only if the
+ data type ``wchar_t`` is unsigned and the front-end is in C++ mode.
+
+``__REGISTER_PREFIX__``
+ This macro expands to a single token (not a string constant) which is
+ the prefix applied to CPU register names in assembly language for this
+ target. You can use it to write assembly that is usable in multiple
+ environments. For example, in the ``m68k-aout`` environment it
+ expands to nothing, but in the ``m68k-coff`` environment it expands
+ to a single :samp:`%`.
+
+``__USER_LABEL_PREFIX__``
+ This macro expands to a single token which is the prefix applied to
+ user labels (symbols visible to C code) in assembly. For example, in
+ the ``m68k-aout`` environment it expands to an :samp:`_`, but in the
+ ``m68k-coff`` environment it expands to nothing.
+
+ This macro will have the correct definition even if
+ :option:`-f(no-)underscores` is in use, but it will not be correct if
+ target-specific options that adjust this prefix are used (e.g. the
+ OSF/rose :option:`-mno-underscores` option).
+
+``__SIZE_TYPE__`` ``__PTRDIFF_TYPE__`` ``__WCHAR_TYPE__`` ``__WINT_TYPE__`` ``__INTMAX_TYPE__`` ``__UINTMAX_TYPE__`` ``__SIG_ATOMIC_TYPE__`` ``__INT8_TYPE__`` ``__INT16_TYPE__`` ``__INT32_TYPE__`` ``__INT64_TYPE__`` ``__UINT8_TYPE__`` ``__UINT16_TYPE__`` ``__UINT32_TYPE__`` ``__UINT64_TYPE__`` ``__INT_LEAST8_TYPE__`` ``__INT_LEAST16_TYPE__`` ``__INT_LEAST32_TYPE__`` ``__INT_LEAST64_TYPE__`` ``__UINT_LEAST8_TYPE__`` ``__UINT_LEAST16_TYPE__`` ``__UINT_LEAST32_TYPE__`` ``__UINT_LEAST64_TYPE__`` ``__INT_FAST8_TYPE__`` ``__INT_FAST16_TYPE__`` ``__INT_FAST32_TYPE__`` ``__INT_FAST64_TYPE__`` ``__UINT_FAST8_TYPE__`` ``__UINT_FAST16_TYPE__`` ``__UINT_FAST32_TYPE__`` ``__UINT_FAST64_TYPE__`` ``__INTPTR_TYPE__`` ``__UINTPTR_TYPE__``
+ These macros are defined to the correct underlying types for the
+ ``size_t``, ``ptrdiff_t``, ``wchar_t``, ``wint_t``,
+ ``intmax_t``, ``uintmax_t``, ``sig_atomic_t``, ``int8_t``,
+ ``int16_t``, ``int32_t``, ``int64_t``, ``uint8_t``,
+ ``uint16_t``, ``uint32_t``, ``uint64_t``,
+ ``int_least8_t``, ``int_least16_t``, ``int_least32_t``,
+ ``int_least64_t``, ``uint_least8_t``, ``uint_least16_t``,
+ ``uint_least32_t``, ``uint_least64_t``, ``int_fast8_t``,
+ ``int_fast16_t``, ``int_fast32_t``, ``int_fast64_t``,
+ ``uint_fast8_t``, ``uint_fast16_t``, ``uint_fast32_t``,
+ ``uint_fast64_t``, ``intptr_t``, and ``uintptr_t`` typedefs,
+ respectively. They exist to make the standard header files
+ :samp:`stddef.h`, :samp:`stdint.h`, and :samp:`wchar.h` work correctly.
+ You should not use these macros directly; instead, include the
+ appropriate headers and use the typedefs. Some of these macros may
+ not be defined on particular systems if GCC does not provide a
+ :samp:`stdint.h` header on those systems.
+
+``__CHAR_BIT__``
+ Defined to the number of bits used in the representation of the
+ ``char`` data type. It exists to make the standard header given
+ numerical limits work correctly. You should not use
+ this macro directly; instead, include the appropriate headers.
+
+``__SCHAR_MAX__`` ``__WCHAR_MAX__`` ``__SHRT_MAX__`` ``__INT_MAX__`` ``__LONG_MAX__`` ``__LONG_LONG_MAX__`` ``__WINT_MAX__`` ``__SIZE_MAX__`` ``__PTRDIFF_MAX__`` ``__INTMAX_MAX__`` ``__UINTMAX_MAX__`` ``__SIG_ATOMIC_MAX__`` ``__INT8_MAX__`` ``__INT16_MAX__`` ``__INT32_MAX__`` ``__INT64_MAX__`` ``__UINT8_MAX__`` ``__UINT16_MAX__`` ``__UINT32_MAX__`` ``__UINT64_MAX__`` ``__INT_LEAST8_MAX__`` ``__INT_LEAST16_MAX__`` ``__INT_LEAST32_MAX__`` ``__INT_LEAST64_MAX__`` ``__UINT_LEAST8_MAX__`` ``__UINT_LEAST16_MAX__`` ``__UINT_LEAST32_MAX__`` ``__UINT_LEAST64_MAX__`` ``__INT_FAST8_MAX__`` ``__INT_FAST16_MAX__`` ``__INT_FAST32_MAX__`` ``__INT_FAST64_MAX__`` ``__UINT_FAST8_MAX__`` ``__UINT_FAST16_MAX__`` ``__UINT_FAST32_MAX__`` ``__UINT_FAST64_MAX__`` ``__INTPTR_MAX__`` ``__UINTPTR_MAX__`` ``__WCHAR_MIN__`` ``__WINT_MIN__`` ``__SIG_ATOMIC_MIN__``
+ Defined to the maximum value of the ``signed char``, ``wchar_t``,
+ ``signed short``,
+ ``signed int``, ``signed long``, ``signed long long``,
+ ``wint_t``, ``size_t``, ``ptrdiff_t``,
+ ``intmax_t``, ``uintmax_t``, ``sig_atomic_t``, ``int8_t``,
+ ``int16_t``, ``int32_t``, ``int64_t``, ``uint8_t``,
+ ``uint16_t``, ``uint32_t``, ``uint64_t``,
+ ``int_least8_t``, ``int_least16_t``, ``int_least32_t``,
+ ``int_least64_t``, ``uint_least8_t``, ``uint_least16_t``,
+ ``uint_least32_t``, ``uint_least64_t``, ``int_fast8_t``,
+ ``int_fast16_t``, ``int_fast32_t``, ``int_fast64_t``,
+ ``uint_fast8_t``, ``uint_fast16_t``, ``uint_fast32_t``,
+ ``uint_fast64_t``, ``intptr_t``, and ``uintptr_t`` types and
+ to the minimum value of the ``wchar_t``, ``wint_t``, and
+ ``sig_atomic_t`` types respectively. They exist to make the
+ standard header given numerical limits work correctly. You should not
+ use these macros directly; instead, include the appropriate headers.
+ Some of these macros may not be defined on particular systems if GCC
+ does not provide a :samp:`stdint.h` header on those systems.
+
+``__INT8_C`` ``__INT16_C`` ``__INT32_C`` ``__INT64_C`` ``__UINT8_C`` ``__UINT16_C`` ``__UINT32_C`` ``__UINT64_C`` ``__INTMAX_C`` ``__UINTMAX_C``
+ Defined to implementations of the standard :samp:`stdint.h` macros with
+ the same names without the leading ``__``. They exist the make the
+ implementation of that header work correctly. You should not use
+ these macros directly; instead, include the appropriate headers. Some
+ of these macros may not be defined on particular systems if GCC does
+ not provide a :samp:`stdint.h` header on those systems.
+
+``__SCHAR_WIDTH__`` ``__SHRT_WIDTH__`` ``__INT_WIDTH__`` ``__LONG_WIDTH__`` ``__LONG_LONG_WIDTH__`` ``__PTRDIFF_WIDTH__`` ``__SIG_ATOMIC_WIDTH__`` ``__SIZE_WIDTH__`` ``__WCHAR_WIDTH__`` ``__WINT_WIDTH__`` ``__INT_LEAST8_WIDTH__`` ``__INT_LEAST16_WIDTH__`` ``__INT_LEAST32_WIDTH__`` ``__INT_LEAST64_WIDTH__`` ``__INT_FAST8_WIDTH__`` ``__INT_FAST16_WIDTH__`` ``__INT_FAST32_WIDTH__`` ``__INT_FAST64_WIDTH__`` ``__INTPTR_WIDTH__`` ``__INTMAX_WIDTH__``
+ Defined to the bit widths of the corresponding types. They exist to
+ make the implementations of :samp:`limits.h` and :samp:`stdint.h` behave
+ correctly. You should not use these macros directly; instead, include
+ the appropriate headers. Some of these macros may not be defined on
+ particular systems if GCC does not provide a :samp:`stdint.h` header on
+ those systems.
+
+``__SIZEOF_INT__`` ``__SIZEOF_LONG__`` ``__SIZEOF_LONG_LONG__`` ``__SIZEOF_SHORT__`` ``__SIZEOF_POINTER__`` ``__SIZEOF_FLOAT__`` ``__SIZEOF_DOUBLE__`` ``__SIZEOF_LONG_DOUBLE__`` ``__SIZEOF_SIZE_T__`` ``__SIZEOF_WCHAR_T__`` ``__SIZEOF_WINT_T__`` ``__SIZEOF_PTRDIFF_T__``
+ Defined to the number of bytes of the C standard data types: ``int``,
+ ``long``, ``long long``, ``short``, ``void *``, ``float``,
+ ``double``, ``long double``, ``size_t``, ``wchar_t``, ``wint_t``
+ and ``ptrdiff_t``.
+
+``__BYTE_ORDER__`` ``__ORDER_LITTLE_ENDIAN__`` ``__ORDER_BIG_ENDIAN__`` ``__ORDER_PDP_ENDIAN__``
+ ``__BYTE_ORDER__`` is defined to one of the values
+ ``__ORDER_LITTLE_ENDIAN__``, ``__ORDER_BIG_ENDIAN__``, or
+ ``__ORDER_PDP_ENDIAN__`` to reflect the layout of multi-byte and
+ multi-word quantities in memory. If ``__BYTE_ORDER__`` is equal to
+ ``__ORDER_LITTLE_ENDIAN__`` or ``__ORDER_BIG_ENDIAN__``, then
+ multi-byte and multi-word quantities are laid out identically: the
+ byte (word) at the lowest address is the least significant or most
+ significant byte (word) of the quantity, respectively. If
+ ``__BYTE_ORDER__`` is equal to ``__ORDER_PDP_ENDIAN__``, then
+ bytes in 16-bit words are laid out in a little-endian fashion, whereas
+ the 16-bit subwords of a 32-bit quantity are laid out in big-endian
+ fashion.
+
+ You should use these macros for testing like this:
+
+ .. code-block:: c++
+
+ /* Test for a little-endian machine */
+ #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+
+``__FLOAT_WORD_ORDER__``
+ ``__FLOAT_WORD_ORDER__`` is defined to one of the values
+ ``__ORDER_LITTLE_ENDIAN__`` or ``__ORDER_BIG_ENDIAN__`` to reflect
+ the layout of the words of multi-word floating-point quantities.
+
+``__DEPRECATED``
+ This macro is defined, with value 1, when compiling a C++ source file
+ with warnings about deprecated constructs enabled. These warnings are
+ enabled by default, but can be disabled with :option:`-Wno-deprecated`.
+
+``__EXCEPTIONS``
+ This macro is defined, with value 1, when compiling a C++ source file
+ with exceptions enabled. If :option:`-fno-exceptions` is used when
+ compiling the file, then this macro is not defined.
+
+``__GXX_RTTI``
+ This macro is defined, with value 1, when compiling a C++ source file
+ with runtime type identification enabled. If :option:`-fno-rtti` is
+ used when compiling the file, then this macro is not defined.
+
+``__USING_SJLJ_EXCEPTIONS__``
+ This macro is defined, with value 1, if the compiler uses the old
+ mechanism based on ``setjmp`` and ``longjmp`` for exception
+ handling.
+
+``__GXX_EXPERIMENTAL_CXX0X__``
+ This macro is defined when compiling a C++ source file with C++11 features
+ enabled, i.e., for all C++ language dialects except :option:`-std`:samp:`=c++98`
+ and :option:`-std`:samp:`=gnu++98`. This macro is obsolete, but can be used to
+ detect experimental C++0x features in very old versions of GCC. Since
+ GCC 4.7.0 the ``__cplusplus`` macro is defined correctly, so most
+ code should test ``__cplusplus >= 201103L`` instead of using this
+ macro.
+
+``__GXX_WEAK__``
+ This macro is defined when compiling a C++ source file. It has the
+ value 1 if the compiler will use weak symbols, COMDAT sections, or
+ other similar techniques to collapse symbols with 'vague linkage'
+ that are defined in multiple translation units. If the compiler will
+ not collapse such symbols, this macro is defined with value 0. In
+ general, user code should not need to make use of this macro; the
+ purpose of this macro is to ease implementation of the C++ runtime
+ library provided with G++.
+
+``__NEXT_RUNTIME__``
+ This macro is defined, with value 1, if (and only if) the NeXT runtime
+ (as in :option:`-fnext-runtime` ) is in use for Objective-C. If the GNU
+ runtime is used, this macro is not defined, so that you can use this
+ macro to determine which runtime (NeXT or GNU) is being used.
+
+``__LP64__`` ``_LP64``
+ These macros are defined, with value 1, if (and only if) the compilation
+ is for a target where ``long int`` and pointer both use 64-bits and
+ ``int`` uses 32-bit.
+
+``__SSP__``
+ This macro is defined, with value 1, when :option:`-fstack-protector` is in
+ use.
+
+``__SSP_ALL__``
+ This macro is defined, with value 2, when :option:`-fstack-protector-all` is
+ in use.
+
+``__SSP_STRONG__``
+ This macro is defined, with value 3, when :option:`-fstack-protector-strong` is
+ in use.
+
+``__SSP_EXPLICIT__``
+ This macro is defined, with value 4, when :option:`-fstack-protector-explicit` is
+ in use.
+
+``__SANITIZE_ADDRESS__``
+ This macro is defined, with value 1, when :option:`-fsanitize`:samp:`=address`
+ or :option:`-fsanitize`:samp:`=kernel-address` are in use.
+
+``__SANITIZE_THREAD__``
+ This macro is defined, with value 1, when :option:`-fsanitize`:samp:`=thread` is in use.
+
+``__TIMESTAMP__``
+ This macro expands to a string constant that describes the date and time
+ of the last modification of the current source file. The string constant
+ contains abbreviated day of the week, month, day of the month, time in
+ hh:mm:ss form, year and looks like ``"Sun Sep 16 01:03:52 1973"``.
+ If the day of the month is less than 10, it is padded with a space on the left.
+
+ If GCC cannot determine the current date, it will emit a warning message
+ (once per compilation) and ``__TIMESTAMP__`` will expand to
+ ``"??? ??? ?? ??:??:?? ????"``.
+
+``__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1`` ``__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2`` ``__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4`` ``__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8`` ``__GCC_HAVE_SYNC_COMPARE_AND_SWAP_16``
+ These macros are defined when the target processor supports atomic compare
+ and swap operations on operands 1, 2, 4, 8 or 16 bytes in length, respectively.
+
+``__HAVE_SPECULATION_SAFE_VALUE``
+ This macro is defined with the value 1 to show that this version of GCC
+ supports ``__builtin_speculation_safe_value``.
+
+``__GCC_HAVE_DWARF2_CFI_ASM``
+ This macro is defined when the compiler is emitting DWARF CFI directives
+ to the assembler. When this is defined, it is possible to emit those same
+ directives in inline assembly.
+
+``__FP_FAST_FMA`` ``__FP_FAST_FMAF`` ``__FP_FAST_FMAL``
+ These macros are defined with value 1 if the backend supports the
+ ``fma``, ``fmaf``, and ``fmal`` builtin functions, so that
+ the include file :samp:`math.h` can define the macros
+ ``FP_FAST_FMA``, ``FP_FAST_FMAF``, and ``FP_FAST_FMAL``
+ for compatibility with the 1999 C standard.
+
+``__FP_FAST_FMAF16`` ``__FP_FAST_FMAF32`` ``__FP_FAST_FMAF64`` ``__FP_FAST_FMAF128`` ``__FP_FAST_FMAF32X`` ``__FP_FAST_FMAF64X`` ``__FP_FAST_FMAF128X``
+ These macros are defined with the value 1 if the backend supports the
+ ``fma`` functions using the additional ``_Floatn`` and
+ ``_Floatnx`` types that are defined in ISO/IEC TS
+ 18661-3:2015. The include file :samp:`math.h` can define the
+ ``FP_FAST_FMAFn`` and ``FP_FAST_FMAFnx`` macros if
+ the user defined ``__STDC_WANT_IEC_60559_TYPES_EXT__`` before
+ including :samp:`math.h`.
+
+``__GCC_IEC_559``
+ This macro is defined to indicate the intended level of support for
+ IEEE 754 (IEC 60559) floating-point arithmetic. It expands to a
+ nonnegative integer value. If 0, it indicates that the combination of
+ the compiler configuration and the command-line options is not
+ intended to support IEEE 754 arithmetic for ``float`` and
+ ``double`` as defined in C99 and C11 Annex F (for example, that the
+ standard rounding modes and exceptions are not supported, or that
+ optimizations are enabled that conflict with IEEE 754 semantics). If
+ 1, it indicates that IEEE 754 arithmetic is intended to be supported;
+ this does not mean that all relevant language features are supported
+ by GCC. If 2 or more, it additionally indicates support for IEEE
+ 754-2008 (in particular, that the binary encodings for quiet and
+ signaling NaNs are as specified in IEEE 754-2008).
+
+ This macro does not indicate the default state of command-line options
+ that control optimizations that C99 and C11 permit to be controlled by
+ standard pragmas, where those standards do not require a particular
+ default state. It does not indicate whether optimizations respect
+ signaling NaN semantics (the macro for that is
+ ``__SUPPORT_SNAN__`` ). It does not indicate support for decimal
+ floating point or the IEEE 754 binary16 and binary128 types.
+
+``__GCC_IEC_559_COMPLEX``
+ This macro is defined to indicate the intended level of support for
+ IEEE 754 (IEC 60559) floating-point arithmetic for complex numbers, as
+ defined in C99 and C11 Annex G. It expands to a nonnegative integer
+ value. If 0, it indicates that the combination of the compiler
+ configuration and the command-line options is not intended to support
+ Annex G requirements (for example, because :option:`-fcx-limited-range`
+ was used). If 1 or more, it indicates that it is intended to support
+ those requirements; this does not mean that all relevant language
+ features are supported by GCC.
+
+``__NO_MATH_ERRNO__``
+ This macro is defined if :option:`-fno-math-errno` is used, or enabled
+ by another option such as :option:`-ffast-math` or by default.
+
+``__GNUC_EXECUTION_CHARSET_NAME`` ``__GNUC_WIDE_EXECUTION_CHARSET_NAME``
+ These macros are defined to expand to a narrow string literal of
+ the name of the narrow and wide compile-time execution character
+ set used. It directly reflects the name passed to the options
+ :option:`-fexec-charset` and :option:`-fwide-exec-charset`, or the defaults
+ documented for those options (that is, it can expand to something like
+ ``"UTF-8"`` ). See :ref:`invocation`.
+
+ .. _system-specific-predefined-macros:
+
+System-specific Predefined Macros
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. index:: system-specific predefined macros
+
+.. index:: predefined macros, system-specific
+
+.. index:: reserved namespace
+
+The C preprocessor normally predefines several macros that indicate what
+type of system and machine is in use. They are obviously different on
+each target supported by GCC. This manual, being for all systems and
+machines, cannot tell you what their names are, but you can use
+:command:`cpp -dM` to see them all. See :ref:`invocation`. All system-specific
+predefined macros expand to a constant value, so you can test them with
+either :samp:`#ifdef` or :samp:`#if`.
+
+The C standard requires that all system-specific macros be part of the
+:dfn:`reserved namespace`. All names which begin with two underscores,
+or an underscore and a capital letter, are reserved for the compiler and
+library to use as they wish. However, historically system-specific
+macros have had names with no special prefix; for instance, it is common
+to find ``unix`` defined on Unix systems. For all such macros, GCC
+provides a parallel macro with two underscores added at the beginning
+and the end. If ``unix`` is defined, ``__unix__`` will be defined
+too. There will never be more than two underscores; the parallel of
+``_mips`` is ``__mips__``.
+
+When the :option:`-ansi` option, or any :option:`-std` option that
+requests strict conformance, is given to the compiler, all the
+system-specific predefined macros outside the reserved namespace are
+suppressed. The parallel macros, inside the reserved namespace, remain
+defined.
+
+We are slowly phasing out all predefined macros which are outside the
+reserved namespace. You should never use them in new programs, and we
+encourage you to correct older code to use the parallel macros whenever
+you find it. We don't recommend you use the system-specific macros that
+are in the reserved namespace, either. It is better in the long run to
+check specifically for features you need, using a tool such as
+:command:`autoconf`.
+
+.. _c++-named-operators:
+
+C++ Named Operators
+^^^^^^^^^^^^^^^^^^^
+
+.. index:: named operators
+
+.. index:: C++ named operators
+
+.. index:: iso646.h
+
+In C++, there are eleven keywords which are simply alternate spellings
+of operators normally written with punctuation. These keywords are
+treated as such even in the preprocessor. They function as operators in
+:samp:`#if`, and they cannot be defined as macros or poisoned. In C, you
+can request that those keywords take their C++ meaning by including
+:samp:`iso646.h`. That header defines each one as a normal object-like
+macro expanding to the appropriate punctuator.
+
+These are the named operators and their corresponding punctuators:
+
+============== ==========
+Named Operator Punctuator
+``and`` ``&&``
+``and_eq`` ``&=``
+``bitand`` ``&``
+``bitor`` ``|``
+``compl`` ``~``
+``not`` ``!``
+``not_eq`` ``!=``
+``or`` ``||``
+``or_eq`` ``|=``
+``xor`` ``^``
+``xor_eq`` ``^=``
+============== ==========
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/stringizing.rst b/gcc/doc/cpp/macros/stringizing.rst
new file mode 100644
index 00000000000..94bf3b785b5
--- /dev/null
+++ b/gcc/doc/cpp/macros/stringizing.rst
@@ -0,0 +1,88 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _stringizing:
+
+Stringizing
+***********
+
+.. index:: stringizing
+
+.. index:: # operator
+
+Sometimes you may want to convert a macro argument into a string
+constant. Parameters are not replaced inside string constants, but you
+can use the :samp:`#` preprocessing operator instead. When a macro
+parameter is used with a leading :samp:`#`, the preprocessor replaces it
+with the literal text of the actual argument, converted to a string
+constant. Unlike normal parameter replacement, the argument is not
+macro-expanded first. This is called :dfn:`stringizing`.
+
+There is no way to combine an argument with surrounding text and
+stringize it all together. Instead, you can write a series of adjacent
+string constants and stringized arguments. The preprocessor
+replaces the stringized arguments with string constants. The C
+compiler then combines all the adjacent string constants into one
+long string.
+
+Here is an example of a macro definition that uses stringizing:
+
+.. code-block::
+
+ #define WARN_IF(EXP) \
+ do { if (EXP) \
+ fprintf (stderr, "Warning: " #EXP "\n"); } \
+ while (0)
+ WARN_IF (x == 0);
+ → do { if (x == 0)
+ fprintf (stderr, "Warning: " "x == 0" "\n"); } while (0);
+
+The argument for ``EXP`` is substituted once, as-is, into the
+``if`` statement, and once, stringized, into the argument to
+``fprintf``. If ``x`` were a macro, it would be expanded in the
+``if`` statement, but not in the string.
+
+The ``do`` and ``while (0)`` are a kludge to make it possible to
+write ``WARN_IF (arg);``, which the resemblance of
+``WARN_IF`` to a function would make C programmers want to do; see
+Swallowing the Semicolon.
+
+Stringizing in C involves more than putting double-quote characters
+around the fragment. The preprocessor backslash-escapes the quotes
+surrounding embedded string constants, and all backslashes within string and
+character constants, in order to get a valid C string constant with the
+proper contents. Thus, stringizing ``p = "foo\n";`` results in
+``"p = \"foo\\n\";"``. However, backslashes that are not inside string
+or character constants are not duplicated: :samp:`\\n` by itself
+stringizes to ``"\n"``.
+
+All leading and trailing whitespace in text being stringized is
+ignored. Any sequence of whitespace in the middle of the text is
+converted to a single space in the stringized result. Comments are
+replaced by whitespace long before stringizing happens, so they
+never appear in stringized text.
+
+There is no way to convert a macro argument into a character constant.
+
+If you want to stringize the result of expansion of a macro argument,
+you have to use two levels of macros.
+
+.. code-block::
+
+ #define xstr(s) str(s)
+ #define str(s) #s
+ #define foo 4
+ str (foo)
+ → "foo"
+ xstr (foo)
+ → xstr (4)
+ → str (4)
+ → "4"
+
+``s`` is stringized when it is used in ``str``, so it is not
+macro-expanded first. But ``s`` is an ordinary argument to
+``xstr``, so it is completely macro-expanded before ``xstr``
+itself is expanded (see :ref:`argument-prescan`). Therefore, by the time
+``str`` gets to its argument, it has already been macro-expanded.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/undefining-and-redefining-macros.rst b/gcc/doc/cpp/macros/undefining-and-redefining-macros.rst
new file mode 100644
index 00000000000..3194a6838c2
--- /dev/null
+++ b/gcc/doc/cpp/macros/undefining-and-redefining-macros.rst
@@ -0,0 +1,71 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _undefining-and-redefining-macros:
+
+Undefining and Redefining Macros
+********************************
+
+.. index:: undefining macros
+
+.. index:: redefining macros
+
+.. index:: #undef
+
+If a macro ceases to be useful, it may be :dfn:`undefined` with the
+:samp:`#undef` directive. :samp:`#undef` takes a single argument, the
+name of the macro to undefine. You use the bare macro name, even if the
+macro is function-like. It is an error if anything appears on the line
+after the macro name. :samp:`#undef` has no effect if the name is not a
+macro.
+
+.. code-block::
+
+ #define FOO 4
+ x = FOO; → x = 4;
+ #undef FOO
+ x = FOO; → x = FOO;
+
+Once a macro has been undefined, that identifier may be :dfn:`redefined`
+as a macro by a subsequent :samp:`#define` directive. The new definition
+need not have any resemblance to the old definition.
+
+However, if an identifier which is currently a macro is redefined, then
+the new definition must be :dfn:`effectively the same` as the old one.
+Two macro definitions are effectively the same if:
+
+* Both are the same type of macro (object- or function-like).
+
+* All the tokens of the replacement list are the same.
+
+* If there are any parameters, they are the same.
+
+* Whitespace appears in the same places in both. It need not be
+ exactly the same amount of whitespace, though. Remember that comments
+ count as whitespace.
+
+These definitions are effectively the same:
+
+.. code-block:: c++
+
+ #define FOUR (2 + 2)
+ #define FOUR (2 + 2)
+ #define FOUR (2 /* two */ + 2)
+
+but these are not:
+
+.. code-block:: c++
+
+ #define FOUR (2 + 2)
+ #define FOUR ( 2+2 )
+ #define FOUR (2 * 2)
+ #define FOUR(score,and,seven,years,ago) (2 + 2)
+
+If a macro is redefined with a definition that is not effectively the
+same as the old one, the preprocessor issues a warning and changes the
+macro to use the new definition. If the new definition is effectively
+the same, the redefinition is silently ignored. This allows, for
+instance, two different headers to define a common macro. The
+preprocessor will only complain if the definitions do not match.
\ No newline at end of file
diff --git a/gcc/doc/cpp/macros/variadic-macros.rst b/gcc/doc/cpp/macros/variadic-macros.rst
new file mode 100644
index 00000000000..c96ab107654
--- /dev/null
+++ b/gcc/doc/cpp/macros/variadic-macros.rst
@@ -0,0 +1,145 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _variadic-macros:
+
+Variadic Macros
+***************
+
+.. index:: variable number of arguments
+
+.. index:: macros with variable arguments
+
+.. index:: variadic macros
+
+A macro can be declared to accept a variable number of arguments much as
+a function can. The syntax for defining the macro is similar to that of
+a function. Here is an example:
+
+.. code-block:: c++
+
+ #define eprintf(...) fprintf (stderr, __VA_ARGS__)
+
+This kind of macro is called :dfn:`variadic`. When the macro is invoked,
+all the tokens in its argument list after the last named argument (this
+macro has none), including any commas, become the :dfn:`variable
+argument`. This sequence of tokens replaces the identifier
+``__VA_ARGS__`` in the macro body wherever it appears. Thus, we
+have this expansion:
+
+.. code-block::
+
+ eprintf ("%s:%d: ", input_file, lineno)
+ → fprintf (stderr, "%s:%d: ", input_file, lineno)
+
+The variable argument is completely macro-expanded before it is inserted
+into the macro expansion, just like an ordinary argument. You may use
+the :samp:`#` and :samp:`##` operators to stringize the variable argument
+or to paste its leading or trailing token with another token. (But see
+below for an important special case for :samp:`##`.)
+
+If your macro is complicated, you may want a more descriptive name for
+the variable argument than ``__VA_ARGS__``. CPP permits
+this, as an extension. You may write an argument name immediately
+before the :samp:`...`; that name is used for the variable argument.
+The ``eprintf`` macro above could be written
+
+.. code-block:: c++
+
+ #define eprintf(args...) fprintf (stderr, args)
+
+using this extension. You cannot use ``__VA_ARGS__`` and this
+extension in the same macro.
+
+You can have named arguments as well as variable arguments in a variadic
+macro. We could define ``eprintf`` like this, instead:
+
+.. code-block:: c++
+
+ #define eprintf(format, ...) fprintf (stderr, format, __VA_ARGS__)
+
+This formulation looks more descriptive, but historically it was less
+flexible: you had to supply at least one argument after the format
+string. In standard C, you could not omit the comma separating the
+named argument from the variable arguments. (Note that this
+restriction has been lifted in C++2a, and never existed in GNU C; see
+below.)
+
+Furthermore, if you left the variable argument empty, you would have
+gotten a syntax error, because there would have been an extra comma
+after the format string.
+
+.. code-block::
+
+ eprintf("success!\n", );
+ → fprintf(stderr, "success!\n", );
+
+This has been fixed in C++2a, and GNU CPP also has a pair of
+extensions which deal with this problem.
+
+First, in GNU CPP, and in C++ beginning in C++2a, you are allowed to
+leave the variable argument out entirely:
+
+.. code-block::
+
+ eprintf ("success!\n")
+ → fprintf(stderr, "success!\n", );
+
+Second, C++2a introduces the ``__VA_OPT__`` function macro.
+This macro may only appear in the definition of a variadic macro. If
+the variable argument has any tokens, then a ``__VA_OPT__``
+invocation expands to its argument; but if the variable argument does
+not have any tokens, the ``__VA_OPT__`` expands to nothing:
+
+.. code-block:: c++
+
+ #define eprintf(format, ...) \
+ fprintf (stderr, format __VA_OPT__(,) __VA_ARGS__)
+
+``__VA_OPT__`` is also available in GNU C and GNU C++.
+
+Historically, GNU CPP has also had another extension to handle the
+trailing comma: the :samp:`##` token paste operator has a special
+meaning when placed between a comma and a variable argument. Despite
+the introduction of ``__VA_OPT__``, this extension remains
+supported in GNU CPP, for backward compatibility. If you write
+
+.. code-block:: c++
+
+ #define eprintf(format, ...) fprintf (stderr, format, ##__VA_ARGS__)
+
+and the variable argument is left out when the ``eprintf`` macro is
+used, then the comma before the :samp:`##` will be deleted. This does
+*not* happen if you pass an empty argument, nor does it happen if
+the token preceding :samp:`##` is anything other than a comma.
+
+.. code-block::
+
+ eprintf ("success!\n")
+ → fprintf(stderr, "success!\n");
+
+The above explanation is ambiguous about the case where the only macro
+parameter is a variable arguments parameter, as it is meaningless to
+try to distinguish whether no argument at all is an empty argument or
+a missing argument.
+CPP retains the comma when conforming to a specific C
+standard. Otherwise the comma is dropped as an extension to the standard.
+
+The C standard
+mandates that the only place the identifier ``__VA_ARGS__``
+can appear is in the replacement list of a variadic macro. It may not
+be used as a macro name, macro argument name, or within a different type
+of macro. It may also be forbidden in open text; the standard is
+ambiguous. We recommend you avoid using it except for its defined
+purpose.
+
+Likewise, C++ forbids ``__VA_OPT__`` anywhere outside the
+replacement list of a variadic macro.
+
+Variadic macros became a standard part of the C language with C99.
+GNU CPP previously supported them
+with a named variable argument
+(:samp:`args...`, not :samp:`...` and ``__VA_ARGS__`` ), which
+is still supported for backward compatibility.
\ No newline at end of file
diff --git a/gcc/doc/cpp/obsolete-features.rst b/gcc/doc/cpp/obsolete-features.rst
new file mode 100644
index 00000000000..7524b7d1a17
--- /dev/null
+++ b/gcc/doc/cpp/obsolete-features.rst
@@ -0,0 +1,100 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _obsolete-features:
+
+Obsolete Features
+*****************
+
+CPP has some features which are present mainly for compatibility with
+older programs. We discourage their use in new code. In some cases,
+we plan to remove the feature in a future version of GCC.
+
+Assertions
+^^^^^^^^^^
+
+.. index:: assertions
+
+:dfn:`Assertions` are a deprecated alternative to macros in writing
+conditionals to test what sort of computer or system the compiled
+program will run on. Assertions are usually predefined, but you can
+define them with preprocessing directives or command-line options.
+
+Assertions were intended to provide a more systematic way to describe
+the compiler's target system and we added them for compatibility with
+existing compilers. In practice they are just as unpredictable as the
+system-specific predefined macros. In addition, they are not part of
+any standard, and only a few compilers support them.
+Therefore, the use of assertions is **less** portable than the use
+of system-specific predefined macros. We recommend you do not use them at
+all.
+
+.. index:: predicates
+
+An assertion looks like this:
+
+.. code-block:: c++
+
+ #predicate (answer)
+
+:samp:`{predicate}` must be a single identifier. :samp:`{answer}` can be any
+sequence of tokens; all characters are significant except for leading
+and trailing whitespace, and differences in internal whitespace
+sequences are ignored. (This is similar to the rules governing macro
+redefinition.) Thus, ``(x + y)`` is different from ``(x+y)`` but
+equivalent to ``( x + y )``. Parentheses do not nest inside an
+answer.
+
+.. index:: testing predicates
+
+To test an assertion, you write it in an :samp:`#if`. For example, this
+conditional succeeds if either ``vax`` or ``ns16000`` has been
+asserted as an answer for ``machine``.
+
+.. code-block:: c++
+
+ #if #machine (vax) || #machine (ns16000)
+
+You can test whether *any* answer is asserted for a predicate by
+omitting the answer in the conditional:
+
+.. code-block:: c++
+
+ #if #machine
+
+.. index:: #assert
+
+Assertions are made with the :samp:`#assert` directive. Its sole
+argument is the assertion to make, without the leading :samp:`#` that
+identifies assertions in conditionals.
+
+.. code-block:: c++
+
+ #assert predicate (answer)
+
+You may make several assertions with the same predicate and different
+answers. Subsequent assertions do not override previous ones for the
+same predicate. All the answers for any given predicate are
+simultaneously true.
+
+.. index:: assertions, canceling
+
+.. index:: #unassert
+
+Assertions can be canceled with the :samp:`#unassert` directive. It
+has the same syntax as :samp:`#assert`. In that form it cancels only the
+answer which was specified on the :samp:`#unassert` line; other answers
+for that predicate remain true. You can cancel an entire predicate by
+leaving out the answer:
+
+.. code-block:: c++
+
+ #unassert predicate
+
+In either form, if no such assertion has been made, :samp:`#unassert` has
+no effect.
+
+You can also make or cancel assertions using command-line options.
+See :ref:`invocation`.
\ No newline at end of file
diff --git a/gcc/doc/cpp/option-index.rst b/gcc/doc/cpp/option-index.rst
new file mode 100644
index 00000000000..77718164b12
--- /dev/null
+++ b/gcc/doc/cpp/option-index.rst
@@ -0,0 +1,6 @@
+Option Index
+============
+
+.. only:: html
+
+ :ref:`genindex`
\ No newline at end of file
diff --git a/gcc/doc/cpp/other-directives.rst b/gcc/doc/cpp/other-directives.rst
new file mode 100644
index 00000000000..1799c04f558
--- /dev/null
+++ b/gcc/doc/cpp/other-directives.rst
@@ -0,0 +1,32 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+ .. _other-directives:
+
+Other Directives
+----------------
+
+.. index:: #ident
+
+.. index:: #sccs
+
+The :samp:`#ident` directive takes one argument, a string constant. On
+some systems, that string constant is copied into a special segment of
+the object file. On other systems, the directive is ignored. The
+:samp:`#sccs` directive is a synonym for :samp:`#ident`.
+
+These directives are not part of the C standard, but they are not
+official GNU extensions either. What historical information we have
+been able to find, suggests they originated with System V.
+
+.. index:: null directive
+
+The :dfn:`null directive` consists of a :samp:`#` followed by a newline,
+with only whitespace (including comments) in between. A null directive
+is understood as a preprocessing directive but has no effect on the
+preprocessor output. The primary significance of the existence of the
+null directive is that an input line consisting of just a :samp:`#` will
+produce no output, rather than a line of output containing just a
+:samp:`#`. Supposedly some old C programs contain such lines.
\ No newline at end of file
diff --git a/gcc/doc/cpp/overview.rst b/gcc/doc/cpp/overview.rst
new file mode 100644
index 00000000000..c09276d640c
--- /dev/null
+++ b/gcc/doc/cpp/overview.rst
@@ -0,0 +1,66 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _overview:
+
+Overview
+--------
+
+The C preprocessor, often known as :dfn:`cpp`, is a :dfn:`macro processor`
+that is used automatically by the C compiler to transform your program
+before compilation. It is called a macro processor because it allows
+you to define :dfn:`macros`, which are brief abbreviations for longer
+constructs.
+
+The C preprocessor is intended to be used only with C, C++, and
+Objective-C source code. In the past, it has been abused as a general
+text processor. It will choke on input which does not obey C's lexical
+rules. For example, apostrophes will be interpreted as the beginning of
+character constants, and cause errors. Also, you cannot rely on it
+preserving characteristics of the input which are not significant to
+C-family languages. If a Makefile is preprocessed, all the hard tabs
+will be removed, and the Makefile will not work.
+
+Having said that, you can often get away with using cpp on things which
+are not C. Other Algol-ish programming languages are often safe
+(Ada, etc.) So is assembly, with caution. :option:`-traditional-cpp`
+mode preserves more white space, and is otherwise more permissive. Many
+of the problems can be avoided by writing C or C++ style comments
+instead of native language comments, and keeping macros simple.
+
+Wherever possible, you should use a preprocessor geared to the language
+you are writing in. Modern versions of the GNU assembler have macro
+facilities. Most high level programming languages have their own
+conditional compilation and inclusion mechanism. If all else fails,
+try a true general text processor, such as GNU M4.
+
+C preprocessors vary in some details. This manual discusses the GNU C
+preprocessor, which provides a small superset of the features of ISO
+Standard C. In its default mode, the GNU C preprocessor does not do a
+few things required by the standard. These are features which are
+rarely, if ever, used, and may cause surprising changes to the meaning
+of a program which does not expect them. To get strict ISO Standard C,
+you should use the :option:`-std`:samp:`=c90`, :option:`-std`:samp:`=c99`,
+:option:`-std`:samp:`=c11` or :option:`-std`:samp:`=c17` options, depending
+on which version of the standard you want. To get all the mandatory
+diagnostics, you must also use :option:`-pedantic`. See :ref:`invocation`.
+
+This manual describes the behavior of the ISO preprocessor. To
+minimize gratuitous differences, where the ISO preprocessor's
+behavior does not conflict with traditional semantics, the
+traditional preprocessor should behave the same way. The various
+differences that do exist are detailed in the section Traditional
+Mode.
+
+For clarity, unless noted otherwise, references to :samp:`CPP` in this
+manual refer to GNU CPP.
+
+.. toctree::
+ :maxdepth: 2
+
+ character-sets
+ initial-processing
+ tokenization
+ the-preprocessing-language
\ No newline at end of file
diff --git a/gcc/doc/cpp/pragmas.rst b/gcc/doc/cpp/pragmas.rst
new file mode 100644
index 00000000000..40d037260a9
--- /dev/null
+++ b/gcc/doc/cpp/pragmas.rst
@@ -0,0 +1,121 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _pragmas:
+
+Pragmas
+-------
+
+.. index:: pragma directive
+
+The :samp:`#pragma` directive is the method specified by the C standard
+for providing additional information to the compiler, beyond what is
+conveyed in the language itself. The forms of this directive
+(commonly known as :dfn:`pragmas`) specified by C standard are prefixed with
+``STDC``. A C compiler is free to attach any meaning it likes to other
+pragmas. Most GNU-defined, supported pragmas have been given a
+``GCC`` prefix.
+
+.. index:: _Pragma
+
+C99 introduced the ``_Pragma`` operator. This feature addresses a
+major problem with :samp:`#pragma`: being a directive, it cannot be
+produced as the result of macro expansion. ``_Pragma`` is an
+operator, much like ``sizeof`` or ``defined``, and can be embedded
+in a macro.
+
+Its syntax is ``_Pragma (string-literal)``, where
+:samp:`{string-literal}` can be either a normal or wide-character string
+literal. It is destringized, by replacing all :samp:`\\\\` with a single
+:samp:`\\` and all :samp:`\\"` with a :samp:`"`. The result is then
+processed as if it had appeared as the right hand side of a
+:samp:`#pragma` directive. For example,
+
+.. code-block:: c++
+
+ _Pragma ("GCC dependency \"parse.y\"")
+
+has the same effect as ``#pragma GCC dependency "parse.y"``. The
+same effect could be achieved using macros, for example
+
+.. code-block:: c++
+
+ #define DO_PRAGMA(x) _Pragma (#x)
+ DO_PRAGMA (GCC dependency "parse.y")
+
+The standard is unclear on where a ``_Pragma`` operator can appear.
+The preprocessor does not accept it within a preprocessing conditional
+directive like :samp:`#if`. To be safe, you are probably best keeping it
+out of directives other than :samp:`#define`, and putting it on a line of
+its own.
+
+This manual documents the pragmas which are meaningful to the
+preprocessor itself. Other pragmas are meaningful to the C or C++
+compilers. They are documented in the GCC manual.
+
+GCC plugins may provide their own pragmas.
+
+``#pragma GCC dependency``
+ ``#pragma GCC dependency`` allows you to check the relative dates of
+ the current file and another file. If the other file is more recent than
+ the current file, a warning is issued. This is useful if the current
+ file is derived from the other file, and should be regenerated. The
+ other file is searched for using the normal include search path.
+ Optional trailing text can be used to give more information in the
+ warning message.
+
+ .. code-block:: c++
+
+ #pragma GCC dependency "parse.y"
+ #pragma GCC dependency "/usr/include/time.h" rerun fixincludes
+
+``#pragma GCC poison``
+ Sometimes, there is an identifier that you want to remove completely
+ from your program, and make sure that it never creeps back in. To
+ enforce this, you can :dfn:`poison` the identifier with this pragma.
+ ``#pragma GCC poison`` is followed by a list of identifiers to
+ poison. If any of those identifiers appears anywhere in the source
+ after the directive, it is a hard error. For example,
+
+ .. code-block:: c++
+
+ #pragma GCC poison printf sprintf fprintf
+ sprintf(some_string, "hello");
+
+ will produce an error.
+
+ If a poisoned identifier appears as part of the expansion of a macro
+ which was defined before the identifier was poisoned, it will *not*
+ cause an error. This lets you poison an identifier without worrying
+ about system headers defining macros that use it.
+
+ For example,
+
+ .. code-block:: c++
+
+ #define strrchr rindex
+ #pragma GCC poison rindex
+ strrchr(some_string, 'h');
+
+ will not produce an error.
+
+``#pragma GCC system_header``
+ This pragma takes no arguments. It causes the rest of the code in the
+ current file to be treated as if it came from a system header.
+ See :ref:`system-headers`.
+
+``#pragma GCC warning`` :samp:`{#pragma GCC error}#pragma GCC error`
+ ``#pragma GCC warning "message"`` causes the preprocessor to issue
+ a warning diagnostic with the text :samp:`message`. The message
+ contained in the pragma must be a single string literal. Similarly,
+ ``#pragma GCC error "message"`` issues an error message. Unlike
+ the :samp:`#warning` and :samp:`#error` directives, these pragmas can be
+ embedded in preprocessor macros using :samp:`_Pragma`.
+
+``#pragma once``
+ If ``#pragma once`` is seen when scanning a header file, that
+ file will never be read again, no matter what. It is a less-portable
+ alternative to using :samp:`#ifndef` to guard the contents of header files
+ against multiple inclusions.
\ No newline at end of file
diff --git a/gcc/doc/cpp/preprocessor-output.rst b/gcc/doc/cpp/preprocessor-output.rst
new file mode 100644
index 00000000000..8aff8b36ea0
--- /dev/null
+++ b/gcc/doc/cpp/preprocessor-output.rst
@@ -0,0 +1,86 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _preprocessor-output:
+
+Preprocessor Output
+-------------------
+
+When the C preprocessor is used with the C, C++, or Objective-C
+compilers, it is integrated into the compiler and communicates a stream
+of binary tokens directly to the compiler's parser. However, it can
+also be used in the more conventional standalone mode, where it produces
+textual output.
+
+.. FIXME: Document the library interface.
+
+.. index:: output format
+
+The output from the C preprocessor looks much like the input, except
+that all preprocessing directive lines have been replaced with blank
+lines and all comments with spaces. Long runs of blank lines are
+discarded.
+
+The ISO standard specifies that it is implementation defined whether a
+preprocessor preserves whitespace between tokens, or replaces it with
+e.g. a single space. In GNU CPP, whitespace between tokens is collapsed
+to become a single space, with the exception that the first token on a
+non-directive line is preceded with sufficient spaces that it appears in
+the same column in the preprocessed output that it appeared in the
+original source file. This is so the output is easy to read.
+CPP does not insert any
+whitespace where there was none in the original source, except where
+necessary to prevent an accidental token paste.
+
+.. index:: linemarkers
+
+Source file name and line number information is conveyed by lines
+of the form
+
+.. code-block:: c++
+
+ # linenum filename flags
+
+These are called :dfn:`linemarkers`. They are inserted as needed into
+the output (but never within a string or character constant). They mean
+that the following line originated in file :samp:`{filename}` at line
+:samp:`{linenum}`. :samp:`{filename}` will never contain any non-printing
+characters; they are replaced with octal escape sequences.
+
+After the file name comes zero or more flags, which are :samp:`1`,
+:samp:`2`, :samp:`3`, or :samp:`4`. If there are multiple flags, spaces
+separate them. Here is what the flags mean:
+
+:samp:`1`
+ This indicates the start of a new file.
+
+:samp:`2`
+ This indicates returning to a file (after having included another file).
+
+:samp:`3`
+ This indicates that the following text comes from a system header file,
+ so certain warnings should be suppressed.
+
+:samp:`4`
+ This indicates that the following text should be treated as being
+ wrapped in an implicit ``extern "C"`` block.
+
+ .. maybe cross reference SYSTEM_IMPLICIT_EXTERN_C
+
+As an extension, the preprocessor accepts linemarkers in non-assembler
+input files. They are treated like the corresponding :samp:`#line`
+directive, (see :ref:`line-control`), except that trailing flags are
+permitted, and are interpreted with the meanings described above. If
+multiple flags are given, they must be in ascending order.
+
+Some directives may be duplicated in the output of the preprocessor.
+These are :samp:`#ident` (always), :samp:`#pragma` (only if the
+preprocessor does not handle the pragma itself), and :samp:`#define` and
+:samp:`#undef` (with certain debugging options). If this happens, the
+:samp:`#` of the directive will always be in the first column, and there
+will be no space between the :samp:`#` and the directive name. If macro
+expansion happens to generate tokens which might be mistaken for a
+duplicated directive, a space will be inserted between the :samp:`#` and
+the directive name.
\ No newline at end of file
diff --git a/gcc/doc/cpp/the-preprocessing-language.rst b/gcc/doc/cpp/the-preprocessing-language.rst
new file mode 100644
index 00000000000..83136439cc8
--- /dev/null
+++ b/gcc/doc/cpp/the-preprocessing-language.rst
@@ -0,0 +1,75 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _the-preprocessing-language:
+
+The preprocessing language
+**************************
+
+.. index:: directives
+
+.. index:: preprocessing directives
+
+.. index:: directive line
+
+.. index:: directive name
+
+After tokenization, the stream of tokens may simply be passed straight
+to the compiler's parser. However, if it contains any operations in the
+:dfn:`preprocessing language`, it will be transformed first. This stage
+corresponds roughly to the standard's 'translation phase 4' and is
+what most people think of as the preprocessor's job.
+
+The preprocessing language consists of :dfn:`directives` to be executed
+and :dfn:`macros` to be expanded. Its primary capabilities are:
+
+* Inclusion of header files. These are files of declarations that can be
+ substituted into your program.
+
+* Macro expansion. You can define :dfn:`macros`, which are abbreviations
+ for arbitrary fragments of C code. The preprocessor will replace the
+ macros with their definitions throughout the program. Some macros are
+ automatically defined for you.
+
+* Conditional compilation. You can include or exclude parts of the
+ program according to various conditions.
+
+* Line control. If you use a program to combine or rearrange source files
+ into an intermediate file which is then compiled, you can use line
+ control to inform the compiler where each source line originally came
+ from.
+
+* Diagnostics. You can detect problems at compile time and issue errors
+ or warnings.
+
+There are a few more, less useful, features.
+
+Except for expansion of predefined macros, all these operations are
+triggered with :dfn:`preprocessing directives`. Preprocessing directives
+are lines in your program that start with :samp:`#`. Whitespace is
+allowed before and after the :samp:`#`. The :samp:`#` is followed by an
+identifier, the :dfn:`directive name`. It specifies the operation to
+perform. Directives are commonly referred to as :samp:`#{name}`
+where :samp:`{name}` is the directive name. For example, :samp:`#define` is
+the directive that defines a macro.
+
+The :samp:`#` which begins a directive cannot come from a macro
+expansion. Also, the directive name is not macro expanded. Thus, if
+``foo`` is defined as a macro expanding to ``define``, that does
+not make :samp:`#foo` a valid preprocessing directive.
+
+The set of valid directive names is fixed. Programs cannot define new
+preprocessing directives.
+
+Some directives require arguments; these make up the rest of the
+directive line and must be separated from the directive name by
+whitespace. For example, :samp:`#define` must be followed by a macro
+name and the intended expansion of the macro.
+
+A preprocessing directive cannot cover more than one line. The line
+may, however, be continued with backslash-newline, or by a block comment
+which extends past the end of the line. In either case, when the
+directive is processed, the continuations have already been merged with
+the first line to make one long line.
\ No newline at end of file
diff --git a/gcc/doc/cpp/tokenization.rst b/gcc/doc/cpp/tokenization.rst
new file mode 100644
index 00000000000..62089b24780
--- /dev/null
+++ b/gcc/doc/cpp/tokenization.rst
@@ -0,0 +1,182 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _tokenization:
+
+Tokenization
+************
+
+.. index:: tokens
+
+.. index:: preprocessing tokens
+
+After the textual transformations are finished, the input file is
+converted into a sequence of :dfn:`preprocessing tokens`. These mostly
+correspond to the syntactic tokens used by the C compiler, but there are
+a few differences. White space separates tokens; it is not itself a
+token of any kind. Tokens do not have to be separated by white space,
+but it is often necessary to avoid ambiguities.
+
+When faced with a sequence of characters that has more than one possible
+tokenization, the preprocessor is greedy. It always makes each token,
+starting from the left, as big as possible before moving on to the next
+token. For instance, ``a+++++b`` is interpreted as
+``a ++ ++ + b``, not as ``a ++ + ++ b``, even though the
+latter tokenization could be part of a valid C program and the former
+could not.
+
+Once the input file is broken into tokens, the token boundaries never
+change, except when the :samp:`##` preprocessing operator is used to paste
+tokens together. See :ref:`concatenation`. For example,
+
+.. code-block::
+
+ #define foo() bar
+ foo()baz
+ → bar baz
+ not
+ → barbaz
+
+The compiler does not re-tokenize the preprocessor's output. Each
+preprocessing token becomes one compiler token.
+
+.. index:: identifiers
+
+Preprocessing tokens fall into five broad classes: identifiers,
+preprocessing numbers, string literals, punctuators, and other. An
+:dfn:`identifier` is the same as an identifier in C: any sequence of
+letters, digits, or underscores, which begins with a letter or
+underscore. Keywords of C have no significance to the preprocessor;
+they are ordinary identifiers. You can define a macro whose name is a
+keyword, for instance. The only identifier which can be considered a
+preprocessing keyword is ``defined``. See :ref:`defined`.
+
+This is mostly true of other languages which use the C preprocessor.
+However, a few of the keywords of C++ are significant even in the
+preprocessor. See :ref:`c++-named-operators`.
+
+In the 1999 C standard, identifiers may contain letters which are not
+part of the 'basic source character set', at the implementation's
+discretion (such as accented Latin letters, Greek letters, or Chinese
+ideograms). This may be done with an extended character set, or the
+:samp:`\\u` and :samp:`\\U` escape sequences.
+
+As an extension, GCC treats :samp:`$` as a letter. This is for
+compatibility with some systems, such as VMS, where :samp:`$` is commonly
+used in system-defined function and object names. :samp:`$` is not a
+letter in strictly conforming mode, or if you specify the :option:`-$`
+option. See :ref:`invocation`.
+
+.. index:: numbers
+
+.. index:: preprocessing numbers
+
+A :dfn:`preprocessing number` has a rather bizarre definition. The
+category includes all the normal integer and floating point constants
+one expects of C, but also a number of other things one might not
+initially recognize as a number. Formally, preprocessing numbers begin
+with an optional period, a required decimal digit, and then continue
+with any sequence of letters, digits, underscores, periods, and
+exponents. Exponents are the two-character sequences :samp:`e+`,
+:samp:`e-`, :samp:`E+`, :samp:`E-`, :samp:`p+`, :samp:`p-`, :samp:`P+`, and
+:samp:`P-`. (The exponents that begin with :samp:`p` or :samp:`P` are
+used for hexadecimal floating-point constants.)
+
+The purpose of this unusual definition is to isolate the preprocessor
+from the full complexity of numeric constants. It does not have to
+distinguish between lexically valid and invalid floating-point numbers,
+which is complicated. The definition also permits you to split an
+identifier at any position and get exactly two tokens, which can then be
+pasted back together with the :samp:`##` operator.
+
+It's possible for preprocessing numbers to cause programs to be
+misinterpreted. For example, ``0xE+12`` is a preprocessing number
+which does not translate to any valid numeric constant, therefore a
+syntax error. It does not mean ``0xE + 12``, which is what you
+might have intended.
+
+.. index:: string literals
+
+.. index:: string constants
+
+.. index:: character constants
+
+.. index:: header file names
+
+.. the @: prevents makeinfo from turning '' into ".
+
+:dfn:`String literals` are string constants, character constants, and
+header file names (the argument of :samp:`#include`) [#f1]_.
+
+String constants and character
+constants are straightforward: ``"..."`` or ``'...'``. In
+either case embedded quotes should be escaped with a backslash:
+``'\''`` is the character constant for :samp:`'`. There is no limit on
+the length of a character constant, but the value of a character
+constant that contains more than one character is
+implementation-defined. See :ref:`implementation-details`.
+
+Header file names either look like string constants, ``"..."``, or are
+written with angle brackets instead, ``<...>``. In either case,
+backslash is an ordinary character. There is no way to escape the
+closing quote or angle bracket. The preprocessor looks for the header
+file in different places depending on which form you use. See :ref:`include-operation`.
+
+No string literal may extend past the end of a line. You may use continued
+lines instead, or string constant concatenation.
+
+.. index:: punctuators
+
+.. index:: digraphs
+
+.. index:: alternative tokens
+
+:dfn:`Punctuators` are all the usual bits of punctuation which are
+meaningful to C and C++. All but three of the punctuation characters in
+ASCII are C punctuators. The exceptions are :samp:`@`, :samp:`$`, and
+:samp:`\``. In addition, all the two- and three-character operators are
+punctuators. There are also six :dfn:`digraphs`, which the C++ standard
+calls :dfn:`alternative tokens`, which are merely alternate ways to spell
+other punctuators. This is a second attempt to work around missing
+punctuation in obsolete systems. It has no negative side effects,
+unlike trigraphs, but does not cover as much ground. The digraphs and
+their corresponding normal punctuators are:
+
+.. code-block::
+
+ Digraph: <% %> <: :> %: %:%:
+ Punctuator: { } [ ] # ##
+
+.. index:: other tokens
+
+Any other single byte is considered 'other' and passed on to the
+preprocessor's output unchanged. The C compiler will almost certainly
+reject source code containing 'other' tokens. In ASCII, the only
+'other' characters are :samp:`@`, :samp:`$`, :samp:`\``, and control
+characters other than NUL (all bits zero). (Note that :samp:`$` is
+normally considered a letter.) All bytes with the high bit set
+(numeric range 0x7F--0xFF) that were not succesfully interpreted as
+part of an extended character in the input encoding are also 'other'
+in the present implementation.
+
+NUL is a special case because of the high probability that its
+appearance is accidental, and because it may be invisible to the user
+(many terminals do not display NUL at all). Within comments, NULs are
+silently ignored, just as any other character would be. In running
+text, NUL is considered white space. For example, these two directives
+have the same meaning.
+
+.. code-block:: c++
+
+ #define X^@1
+ #define X 1
+
+(where :samp:`^@` is ASCII NUL). Within string or character constants,
+NULs are preserved. In the latter two cases the preprocessor emits a
+warning message.
+
+.. [#f1] The C
+ standard uses the term :dfn:`string literal` to refer only to what we are
+ calling :dfn:`string constants`.
\ No newline at end of file
diff --git a/gcc/doc/cpp/traditional-lexical-analysis.rst b/gcc/doc/cpp/traditional-lexical-analysis.rst
new file mode 100644
index 00000000000..7887526a899
--- /dev/null
+++ b/gcc/doc/cpp/traditional-lexical-analysis.rst
@@ -0,0 +1,74 @@
+..
+ Copyright 1988-2021 Free Software Foundation, Inc.
+ This is part of the GCC manual.
+ For copying conditions, see the GPL license file
+
+.. _traditional-lexical-analysis:
+
+Tradit[...]
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