From ae308947ff0fa950431d53bcc90c875295d57715 Mon Sep 17 00:00:00 2001 From: Noah Goldstein Date: Wed, 29 Jun 2022 16:11:22 -0700 Subject: x86: Add support for building {w}memcmp{eq} with explicit ISA level 1. Refactor files so that all implementations are in the multiarch directory - Moved the implementation portion of memcmp sse2 from memcmp.S to multiarch/memcmp-sse2.S - The non-multiarch file now only includes one of the implementations in the multiarch directory based on the compiled ISA level (only used for non-multiarch builds. Otherwise we go through the ifunc selector). 2. Add ISA level build guards to different implementations. - I.e memcmp-avx2-movsb.S which is ISA level 3 will only build if compiled ISA level <= 3. Otherwise there is no reason to include it as we will always use one of the ISA level 4 implementations (memcmp-evex-movbe.S). 3. Add new multiarch/rtld-{w}memcmp{eq}.S that just include the non-multiarch {w}memcmp{eq}.S which will in turn select the best implementation based on the compiled ISA level. 4. Refactor the ifunc selector and ifunc implementation list to use the ISA level aware wrapper macros that allow functions below the compiled ISA level (with a guranteed replacement) to be skipped. Tested with and without multiarch on x86_64 for ISA levels: {generic, x86-64-v2, x86-64-v3, x86-64-v4} And m32 with and without multiarch. --- sysdeps/x86_64/memcmp-isa-default-impl.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 sysdeps/x86_64/memcmp-isa-default-impl.h (limited to 'sysdeps/x86_64/memcmp-isa-default-impl.h') diff --git a/sysdeps/x86_64/memcmp-isa-default-impl.h b/sysdeps/x86_64/memcmp-isa-default-impl.h new file mode 100644 index 0000000000..1e18d157f9 --- /dev/null +++ b/sysdeps/x86_64/memcmp-isa-default-impl.h @@ -0,0 +1,28 @@ +/* Set default memcmp impl based on ISA level. + Copyright (C) 2022 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#if MINIMUM_X86_ISA_LEVEL == 1 || MINIMUM_X86_ISA_LEVEL == 2 +# define DEFAULT_MEMCMP __memcmp_sse2 +#elif MINIMUM_X86_ISA_LEVEL == 3 +# define DEFAULT_MEMCMP __memcmp_avx2_movbe +#elif MINIMUM_X86_ISA_LEVEL == 4 +# define DEFAULT_MEMCMP __memcmp_evex_movbe +#else +# error "Unknown default memcmp implementation" +#endif -- cgit 1.4.1