mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-27 07:20:11 +00:00
8fe57365bf
Optimize strchr/strchrnul/wcschr with AVX2 to search 32 bytes with vector instructions. It is as fast as SSE2 versions for size <= 16 bytes and up to 1X faster for or size > 16 bytes on Haswell. Select AVX2 version on AVX2 machines where vzeroupper is preferred and AVX unaligned load is fast. NB: It uses TZCNT instead of BSF since TZCNT produces the same result as BSF for non-zero input. TZCNT is faster than BSF and is executed as BSF if machine doesn't support TZCNT. * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add strchr-sse2, strchrnul-sse2, strchr-avx2, strchrnul-avx2, wcschr-sse2 and wcschr-avx2. * sysdeps/x86_64/multiarch/ifunc-impl-list.c (__libc_ifunc_impl_list): Add tests for __strchr_avx2, __strchrnul_avx2, __strchrnul_sse2, __wcschr_avx2 and __wcschr_sse2. * sysdeps/x86_64/multiarch/strchr-avx2.S: New file. * sysdeps/x86_64/multiarch/strchr-sse2.S: Likewise. * sysdeps/x86_64/multiarch/strchr.c: Likewise. * sysdeps/x86_64/multiarch/strchrnul-avx2.S: Likewise. * sysdeps/x86_64/multiarch/strchrnul-sse2.S: Likewise. * sysdeps/x86_64/multiarch/strchrnul.c: Likewise. * sysdeps/x86_64/multiarch/wcschr-avx2.S: Likewise. * sysdeps/x86_64/multiarch/wcschr-sse2.S: Likewise. * sysdeps/x86_64/multiarch/wcschr.c: Likewise. * sysdeps/x86_64/multiarch/strchr.S: Removed.
56 lines
1.9 KiB
C
56 lines
1.9 KiB
C
/* Multiple versions of strchr.
|
|
All versions must be listed in ifunc-impl-list.c.
|
|
Copyright (C) 2009-2017 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
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
/* Define multiple versions only for the definition in libc. */
|
|
#if IS_IN (libc)
|
|
# define strchr __redirect_strchr
|
|
# include <string.h>
|
|
# undef strchr
|
|
|
|
# define SYMBOL_NAME strchr
|
|
# include <init-arch.h>
|
|
|
|
extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
|
|
extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2_no_bsf) attribute_hidden;
|
|
extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
|
|
|
|
static inline void *
|
|
IFUNC_SELECTOR (void)
|
|
{
|
|
const struct cpu_features* cpu_features = __get_cpu_features ();
|
|
|
|
if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER)
|
|
&& CPU_FEATURES_ARCH_P (cpu_features, AVX2_Usable)
|
|
&& CPU_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load))
|
|
return OPTIMIZE (avx2);
|
|
|
|
if (CPU_FEATURES_ARCH_P (cpu_features, Slow_BSF))
|
|
return OPTIMIZE (sse2_no_bsf);
|
|
|
|
return OPTIMIZE (sse2);
|
|
}
|
|
|
|
libc_ifunc_redirected (__redirect_strchr, strchr, IFUNC_SELECTOR ());
|
|
weak_alias (strchr, index)
|
|
# ifdef SHARED
|
|
__hidden_ver1 (strchr, __GI_strchr, __redirect_strchr)
|
|
__attribute__((visibility ("hidden")));
|
|
# endif
|
|
#endif
|