[gcc/devel/omp/gcc-12] nvptx: Allow '--with-arch' to override the default '-misa'

[gcc/devel/omp/gcc-12] nvptx: Allow '--with-arch' to override the default '-misa'

[Thomas Schwinge]

https://gcc.gnu.org/g:8cf4c2316cb6a4082bf24fcc3003124e4b0a05c3

commit 8cf4c2316cb6a4082bf24fcc3003124e4b0a05c3
Author: Thomas Schwinge <thomas@codesourcery.com>
Date:   Sat Jun 11 19:37:10 2022 +0200

    nvptx: Allow '--with-arch' to override the default '-misa'
    
            gcc/
            * config.gcc (with_arch) [nvptx]: Allow '--with-arch' to override
            the default.
            * config/nvptx/gen-multilib-matches.sh: New.
            * config/nvptx/t-nvptx (MULTILIB_OPTIONS, MULTILIB_MATCHES)
            (MULTILIB_EXCEPTIONS): Handle this.
            * doc/install.texi (Specific) <nvptx-*-none>: Document this.
            * doc/invoke.texi (Nvidia PTX Options): Likewise.
    
    (cherry picked from commit e9019085e17554c209ca8531022f116b2d7f94fe)

Diff:
---
 gcc/ChangeLog.omp                        | 13 +++++++
 gcc/config.gcc                           |  5 +++
 gcc/config/nvptx/gen-multilib-matches.sh | 60 ++++++++++++++++++++++++++++++++
 gcc/config/nvptx/t-nvptx                 | 21 ++++++++---
 gcc/doc/install.texi                     |  9 +++++
 gcc/doc/invoke.texi                      |  4 ++-
 6 files changed, 106 insertions(+), 6 deletions(-)

diff --git a/gcc/ChangeLog.omp b/gcc/ChangeLog.omp
index 43fa05159b6..ed2073297e7 100644
--- a/gcc/ChangeLog.omp
+++ b/gcc/ChangeLog.omp
@@ -1,3 +1,16 @@
+2022-09-26  Thomas Schwinge  <thomas@codesourcery.com>
+
+	Backported from master:
+	2022-09-26  Thomas Schwinge  <thomas@codesourcery.com>
+
+	* config.gcc (with_arch) [nvptx]: Allow '--with-arch' to override
+	the default.
+	* config/nvptx/gen-multilib-matches.sh: New.
+	* config/nvptx/t-nvptx (MULTILIB_OPTIONS, MULTILIB_MATCHES)
+	(MULTILIB_EXCEPTIONS): Handle this.
+	* doc/install.texi (Specific) <nvptx-*-none>: Document this.
+	* doc/invoke.texi (Nvidia PTX Options): Likewise.
+
 2022-09-26  Thomas Schwinge  <thomas@codesourcery.com>
 
 	Backported from master:
diff --git a/gcc/config.gcc b/gcc/config.gcc
index d492b7769fe..8f51d333668 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -5442,10 +5442,15 @@ case "${target}" in
 	nvptx-*)
 		supported_defaults=arch
 		TM_MULTILIB_CONFIG=$with_arch
+		#TODO 'sm_[...]' list per 'nvptx-sm.def'.
 		case $with_arch in
 			sm_30 )
 				# OK; default.
 				;;
+			sm_35 | sm_53 | sm_70 | sm_75 | sm_80 )
+				# OK, but we'd like 'sm_30', too.
+				TM_MULTILIB_CONFIG="$TM_MULTILIB_CONFIG sm_30"
+				;;
 			* )
 				echo "Unknown arch used in --with-arch=$with_arch" 1>&2
 				exit 1
diff --git a/gcc/config/nvptx/gen-multilib-matches.sh b/gcc/config/nvptx/gen-multilib-matches.sh
new file mode 100755
index 00000000000..9a5878e855b
--- /dev/null
+++ b/gcc/config/nvptx/gen-multilib-matches.sh
@@ -0,0 +1,60 @@
+#!/bin/sh
+
+# Print nvptx 'MULTILIB_MATCHES'
+
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of GCC.
+#
+# GCC is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+#
+# GCC is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+
+set -e
+
+nvptx_sm_def="$1/nvptx-sm.def"
+multilib_options_isa_default=$2
+multilib_options_isa_list=$3
+
+sms=$(grep ^NVPTX_SM $nvptx_sm_def | sed 's/.*(//;s/,.*//')
+
+# Every variant in 'sms' has to either be remapped to the default variant
+# ('.', which is always built), or does get built as non-default variant
+# ('misa=sm_SM'; thus not remapped), or has to be remapped to the "next lower"
+# variant that does get built.
+
+# The "lowest" variant has to be built.
+sm_next_lower=INVALID
+
+for sm in $sms; do
+    if [ x"sm_$sm" = x"$multilib_options_isa_default" ]; then
+	sm_map=.
+    elif expr " $multilib_options_isa_list " : ".* sm_$sm " > /dev/null; then
+	sm_map=
+    else
+	sm_map=$sm_next_lower
+    fi
+
+    if [ x"$sm_map" = x ]; then
+	sm_next_lower=$sm
+    else
+	# Output format as required for 'MULTILIB_MATCHES'.
+	if [ x"$sm_map" = x. ]; then
+	    echo ".=misa?sm_$sm"
+	else
+	    echo "misa?sm_$sm_map=misa?sm_$sm"
+	fi
+
+	sm_next_lower=$sm_map
+    fi
+done
diff --git a/gcc/config/nvptx/t-nvptx b/gcc/config/nvptx/t-nvptx
index c797d57690f..9c5cbda0070 100644
--- a/gcc/config/nvptx/t-nvptx
+++ b/gcc/config/nvptx/t-nvptx
@@ -42,11 +42,22 @@ MULTILIB_OPTIONS += mgomp
 
 multilib_options_isa_list := $(TM_MULTILIB_CONFIG)
 multilib_options_isa_default := $(word 1,$(multilib_options_isa_list))
-# Add the default '-misa' as a multilib option:
-MULTILIB_OPTIONS += misa=$(multilib_options_isa_default)
-# ..., but don't handle it specially (remap to default):
-MULTILIB_MATCHES += .=misa?$(multilib_options_isa_default)
-# ..., and don't actually build it:
+multilib_options_misa_list := $(addprefix misa=,$(multilib_options_isa_list))
+# Add the requested '-misa' variants as a multilib option ('misa=VAR1/misa=VAR2/misa=VAR3' etc.):
+empty :=
+space := $(empty) $(empty)
+MULTILIB_OPTIONS += $(subst $(space),/,$(multilib_options_misa_list))
+# ..., and remap '-misa' variants as appropriate:
+multilib_matches := $(shell $(srcdir)/config/nvptx/gen-multilib-matches.sh $(srcdir)/config/nvptx $(multilib_options_isa_default) "$(multilib_options_isa_list)")
+MULTILIB_MATCHES += $(multilib_matches)
+# ..., and don't actually build what's the default '-misa':
 MULTILIB_EXCEPTIONS += *misa=$(multilib_options_isa_default)*
 
 MULTILIB_OPTIONS += mptx=3.1
+# Filter out invalid '-misa'/'-mptx=3.1' combinations; per 'nvptx-sm.def',
+# 'nvptx.opt:ptx_version', 'nvptx.cc:first_ptx_version_supporting_sm'
+# (that is, '-mptx=3.1' only for sm_30, sm_35 variants):
+MULTILIB_EXCEPTIONS += $(foreach misa,$(filter-out %=sm_30 %=sm_35,$(multilib_options_misa_list)),*$(misa)/mptx=3.1)
+# ..., and special care has to be taken if '-mptx=3.1' is invalid for the
+# default variant:
+MULTILIB_EXCEPTIONS += $(if $(filter-out sm_30 sm_35,$(multilib_options_isa_default)),mgomp/mptx=3.1 mptx=3.1)
diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index ed0d1d882c3..13310d6b981 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -4632,6 +4632,15 @@ the GCC sources.
 Use the @option{--disable-sjlj-exceptions} and
 @option{--enable-newlib-io-long-long} options when configuring.
 
+The @option{--with-arch} option may be specified to override the
+default value for the @option{-march} option, and to also build
+corresponding target libraries.
+The default is @option{--with-arch=sm_30}.
+
+For example, if @option{--with-arch=sm_70} is specified,
+@option{-march=sm_30} and @option{-march=sm_70} target libraries are
+built, and code generation defaults to @option{-march=sm_70}.
+
 @html
 <hr />
 @end html
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 1b290e153d0..3477d4426a0 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -27606,7 +27606,9 @@ supported.
 Generate code for the specified PTX ISA target architecture
 (e.g.@: @samp{sm_35}).  Valid architecture strings are @samp{sm_30},
 @samp{sm_35}, @samp{sm_53}, @samp{sm_70}, @samp{sm_75} and
-@samp{sm_80}.  The default target architecture is sm_30.
+@samp{sm_80}.
+The default depends on how the compiler has been configured, see
+@option{--with-arch}.
 
 This option sets the value of the preprocessor macro
 @code{__PTX_SM__}; for instance, for @samp{sm_35}, it has the value