public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
* [Bug c/105886] New: GCC optimizes structs with FP registers but ignores alignment in this case @ 2022-06-08 11:30 keven.kloeckner at siemens dot com 2022-06-08 22:40 ` [Bug target/105886] -mstrict-align is ignorning unalign in some cases pinskia at gcc dot gnu.org ` (6 more replies) 0 siblings, 7 replies; 8+ messages in thread From: keven.kloeckner at siemens dot com @ 2022-06-08 11:30 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105886 Bug ID: 105886 Summary: GCC optimizes structs with FP registers but ignores alignment in this case Product: gcc Version: 11.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: keven.kloeckner at siemens dot com Target Milestone: --- Compiler output -v: Using built-in specs. COLLECT_GCC=aarch64-elf-gcc.exe COLLECT_LTO_WRAPPER=c:/git/s74100gcc11/s74100cpu/s7p.tools/aarch64_gcc_elf_11.2.0/bin/../libexec/gcc/aarch64-elf/11.2.0/lto-wrapper.exe Target: aarch64-elf Configured with: ../../gcc-11.2.0//configure --host=x86_64-w64-mingw32 --build=x86_64-w64-mingw32 --prefix=/build/aarch64-elf_11.2.0-1/cross-gcc/aarch64-elf --target=aarch64-elf --disable-nls --enable-multilib --with-multilib-list=lp64,ilp32 --enable-languages=c,c++ --disable-decimal-float --with-sysroot=/build/aarch64-elf_11.2.0-1/cross-gcc/aarch64-elf --without-headers --disable-shared --disable-threads --disable-lto --disable-libmudflap --disable-libssp --disable-libgomp --disable-libffi --disable-libstdcxx-pch --disable-win32-registry --with-host-libstdcxx='-static-libgcc -Wl,-Bstatic,-lstdc++,-Bdynamic -lm' --with-newlib --with-gcc --with-gnu-as --with-gnu-ld --with-gmp=/build/aarch64-elf_11.2.0-1/host --with-mpfr=/build/aarch64-elf_11.2.0-1/host --with-mpc=/build/aarch64-elf_11.2.0-1/host --with-isl=/build/aarch64-elf_11.2.0-1/host --with-zstd=/build/aarch64-elf_11.2.0-1/host : (reconfigured) ../../gcc-11.2.0//configure --host=x86_64-w64-mingw32 --build=x86_64-w64-mingw32 --enable-languages=c,c++ --enable-multilib --with-multilib-list=lp64,ilp32 --disable-lto --disable-libmudflap --disable-libssp --disable-libgomp --disable-libffi --with-newlib --with-gcc --with-gnu-ld --with-gnu-as --with-stabs --disable-shared --disable-threads --disable-win32-registry --disable-nls --disable-libstdcxx-pch --with-host-libstdcxx='-static-libgcc -Wl,-Bstatic,-lstdc++,-Bdynamic -lm' --target=aarch64-elf --prefix=/build/aarch64-elf_11.2.0-1/cross-gcc/aarch64-elf --with-gmp=/build/aarch64-elf_11.2.0-1/host --with-mpfr=/build/aarch64-elf_11.2.0-1/host --with-mpc=/build/aarch64-elf_11.2.0-1/host --with-isl=/build/aarch64-elf_11.2.0-1/host --with-zstd=/build/aarch64-elf_11.2.0-1/host --with-sysroot=/build/aarch64-elf_11.2.0-1/cross-gcc/aarch64-elf Thread model: single Supported LTO compression algorithms: zlib zstd gcc version 11.2.0 (GCC) The problem occurs on our Windows to Arm Cortex A53 Cross compile. No errors or warnings during compilation. We have enabled alignment check for some purposes and we cannot disable it. This problem occurs also in C++, not only in C (iam sorry if i put the bug wrong). (for readability i removed all defines and link inputs) Command Line: ../../../../aarch64_gcc_elf_11.2.0/bin/aarch64-elf-gcc -fno-builtin -c -std=gnu11 -Wno-pointer-to-int-cast -Wno-int-to-pointer-cast -Wno-maybe-uninitialized -Werror -mabi=ilp32 -march=armv8-a+crypto+crc -mtune=cortex-a53 -mstrict-align -mno-outline-atomics -Werror=return-type -Werror=format -Werror=address -Werror=array-bounds -Werror=format-extra-args -Werror=init-self -Wno-error=array-bounds -Wno-error=stringop-overflow -Wno-error=free-nonheap-object -mlittle-endian -fno-common -fno-merge-constants -ffunction-sections -fdata-sections -fno-toplevel-reorder -O0 -Werror -nostdinc -ggdb For some reason the GCC 11.2 is using floating point register instructions to optimize initialization of structs if a lot of members are initialized with the same constant successively. The problem is that the GCC generates the following instructions: stp q0, q0, [x0] //128 bit alignment required problem -> usually we use 64 bit //alignment str q0, [x0, #32] // 64 bit alignment -> ok stur q0, [x0, #44] // offset with 32 bit alignment but intruction with 64 bit //required alignment -> hard problem My assumption is the compiler somehow thinks the FP registers are 4 byte or the instructions require 4 byte alignment. I expected the compiler to ensure the alignment if he is optimizing, which i can clearly see he is ignoring or doing it wrong. If more informations are needed please contact me. With kind regards Keven Kloeckner ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/105886] -mstrict-align is ignorning unalign in some cases 2022-06-08 11:30 [Bug c/105886] New: GCC optimizes structs with FP registers but ignores alignment in this case keven.kloeckner at siemens dot com @ 2022-06-08 22:40 ` pinskia at gcc dot gnu.org 2022-06-08 22:40 ` pinskia at gcc dot gnu.org ` (5 subsequent siblings) 6 siblings, 0 replies; 8+ messages in thread From: pinskia at gcc dot gnu.org @ 2022-06-08 22:40 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105886 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |wrong-code Last reconfirmed| |2022-06-08 Summary|GCC optimizes structs with |-mstrict-align is ignorning |FP registers but ignores |unalign in some cases |alignment in this case | Ever confirmed|0 |1 Component|c |target Status|UNCONFIRMED |WAITING --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Can you attach the preprocessed source? ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/105886] -mstrict-align is ignorning unalign in some cases 2022-06-08 11:30 [Bug c/105886] New: GCC optimizes structs with FP registers but ignores alignment in this case keven.kloeckner at siemens dot com 2022-06-08 22:40 ` [Bug target/105886] -mstrict-align is ignorning unalign in some cases pinskia at gcc dot gnu.org @ 2022-06-08 22:40 ` pinskia at gcc dot gnu.org 2022-06-09 10:17 ` keven.kloeckner at siemens dot com ` (4 subsequent siblings) 6 siblings, 0 replies; 8+ messages in thread From: pinskia at gcc dot gnu.org @ 2022-06-08 22:40 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105886 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Depends on| |103100 --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- I suspect this is a dup of bug 103100 really. Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103100 [Bug 103100] [11/12/13 Regression] unaligned access generated with memset or {} and -O2 -mstrict-align ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/105886] -mstrict-align is ignorning unalign in some cases 2022-06-08 11:30 [Bug c/105886] New: GCC optimizes structs with FP registers but ignores alignment in this case keven.kloeckner at siemens dot com 2022-06-08 22:40 ` [Bug target/105886] -mstrict-align is ignorning unalign in some cases pinskia at gcc dot gnu.org 2022-06-08 22:40 ` pinskia at gcc dot gnu.org @ 2022-06-09 10:17 ` keven.kloeckner at siemens dot com 2022-06-09 10:19 ` keven.kloeckner at siemens dot com ` (3 subsequent siblings) 6 siblings, 0 replies; 8+ messages in thread From: keven.kloeckner at siemens dot com @ 2022-06-09 10:17 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105886 --- Comment #3 from Keven <keven.kloeckner at siemens dot com> --- Created attachment 53110 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53110&action=edit precompiled file ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/105886] -mstrict-align is ignorning unalign in some cases 2022-06-08 11:30 [Bug c/105886] New: GCC optimizes structs with FP registers but ignores alignment in this case keven.kloeckner at siemens dot com ` (2 preceding siblings ...) 2022-06-09 10:17 ` keven.kloeckner at siemens dot com @ 2022-06-09 10:19 ` keven.kloeckner at siemens dot com 2022-06-09 10:20 ` keven.kloeckner at siemens dot com ` (2 subsequent siblings) 6 siblings, 0 replies; 8+ messages in thread From: keven.kloeckner at siemens dot com @ 2022-06-09 10:19 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105886 --- Comment #4 from Keven <keven.kloeckner at siemens dot com> --- Created attachment 53111 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53111&action=edit Disassembly screen ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/105886] -mstrict-align is ignorning unalign in some cases 2022-06-08 11:30 [Bug c/105886] New: GCC optimizes structs with FP registers but ignores alignment in this case keven.kloeckner at siemens dot com ` (3 preceding siblings ...) 2022-06-09 10:19 ` keven.kloeckner at siemens dot com @ 2022-06-09 10:20 ` keven.kloeckner at siemens dot com 2022-06-09 10:28 ` pinskia at gcc dot gnu.org 2022-06-09 10:30 ` keven.kloeckner at siemens dot com 6 siblings, 0 replies; 8+ messages in thread From: keven.kloeckner at siemens dot com @ 2022-06-09 10:20 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105886 --- Comment #5 from Keven <keven.kloeckner at siemens dot com> --- Created attachment 53112 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53112&action=edit source file ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/105886] -mstrict-align is ignorning unalign in some cases 2022-06-08 11:30 [Bug c/105886] New: GCC optimizes structs with FP registers but ignores alignment in this case keven.kloeckner at siemens dot com ` (4 preceding siblings ...) 2022-06-09 10:20 ` keven.kloeckner at siemens dot com @ 2022-06-09 10:28 ` pinskia at gcc dot gnu.org 2022-06-09 10:30 ` keven.kloeckner at siemens dot com 6 siblings, 0 replies; 8+ messages in thread From: pinskia at gcc dot gnu.org @ 2022-06-09 10:28 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105886 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |DUPLICATE Status|WAITING |RESOLVED --- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Yes it is a dup of bug 103100 . I hope next week I finish up the patch for it. *** This bug has been marked as a duplicate of bug 103100 *** ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/105886] -mstrict-align is ignorning unalign in some cases 2022-06-08 11:30 [Bug c/105886] New: GCC optimizes structs with FP registers but ignores alignment in this case keven.kloeckner at siemens dot com ` (5 preceding siblings ...) 2022-06-09 10:28 ` pinskia at gcc dot gnu.org @ 2022-06-09 10:30 ` keven.kloeckner at siemens dot com 6 siblings, 0 replies; 8+ messages in thread From: keven.kloeckner at siemens dot com @ 2022-06-09 10:30 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105886 --- Comment #7 from Keven <keven.kloeckner at siemens dot com> --- Thank you for your fast investigation :) ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2022-06-09 10:30 UTC | newest] Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-06-08 11:30 [Bug c/105886] New: GCC optimizes structs with FP registers but ignores alignment in this case keven.kloeckner at siemens dot com 2022-06-08 22:40 ` [Bug target/105886] -mstrict-align is ignorning unalign in some cases pinskia at gcc dot gnu.org 2022-06-08 22:40 ` pinskia at gcc dot gnu.org 2022-06-09 10:17 ` keven.kloeckner at siemens dot com 2022-06-09 10:19 ` keven.kloeckner at siemens dot com 2022-06-09 10:20 ` keven.kloeckner at siemens dot com 2022-06-09 10:28 ` pinskia at gcc dot gnu.org 2022-06-09 10:30 ` keven.kloeckner at siemens dot com
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).