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| author | Leonardo Sandoval <leonardo.sandoval.gonzalez@linux.intel.com> | 2018-05-03 11:09:30 -0500 |
|---|---|---|
| committer | Leonardo Sandoval <leonardo.sandoval.gonzalez@linux.intel.com> | 2018-06-01 16:32:43 -0500 |
| commit | 1457016337072d1b6739f571846b619596990cb7 (patch) | |
| tree | 985983beef1070b9e01f6f31ad974f5038278799 /sysdeps/x86_64/multiarch/wcsncmp.c | |
| parent | e02c026f38505cd474ff1bdaa88fc671804f5805 (diff) | |
| download | glibc-1457016337072d1b6739f571846b619596990cb7.tar.gz glibc-1457016337072d1b6739f571846b619596990cb7.tar.xz glibc-1457016337072d1b6739f571846b619596990cb7.zip | |
x86-64: Optimize strcmp/wcscmp and strncmp/wcsncmp with AVX2
Optimize x86-64 strcmp/wcscmp and strncmp/wcsncmp with AVX2. It uses vector comparison as much as possible. Peak performance observed on a SkyLake machine: 9x, 3x, 2.5x and 5.5x for strcmp, strncmp, wcscmp and wcsncmp, respectively. The larger the comparison length, the more benefit using avx2 functions, except on the strcmp, where peak is observed at length == 32 bytes. Select AVX2 strcmp/wcscmp 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 strcmp-avx2, strncmp-avx2, wcscmp-avx2, wcscmp-sse2, wcsncmp-avx2 and wcsncmp-sse2. * sysdeps/x86_64/multiarch/ifunc-impl-list.c (__libc_ifunc_impl_list): Add tests for __strcmp_avx2, __strncmp_avx2, __wcscmp_avx2, __wcsncmp_avx2, __wcscmp_sse2 and __wcsncmp_sse2. * sysdeps/x86_64/multiarch/strcmp.c (OPTIMIZE (avx2)): (IFUNC_SELECTOR): Return OPTIMIZE (avx2) on AVX 2 machines if AVX unaligned load is fast and vzeroupper is preferred. * sysdeps/x86_64/multiarch/strncmp.c: Likewise. * sysdeps/x86_64/multiarch/strcmp-avx2.S: New file. * sysdeps/x86_64/multiarch/strncmp-avx2.S: Likewise. * sysdeps/x86_64/multiarch/wcscmp-avx2.S: Likewise. * sysdeps/x86_64/multiarch/wcscmp-sse2.S: Likewise. * sysdeps/x86_64/multiarch/wcscmp.c: Likewise. * sysdeps/x86_64/multiarch/wcsncmp-avx2.S: Likewise. * sysdeps/x86_64/multiarch/wcsncmp-sse2.c: Likewise. * sysdeps/x86_64/multiarch/wcsncmp.c: Likewise. * sysdeps/x86_64/wcscmp.S (__wcscmp): Add alias only if __wcscmp is undefined.
Diffstat (limited to 'sysdeps/x86_64/multiarch/wcsncmp.c')
| -rw-r--r-- | sysdeps/x86_64/multiarch/wcsncmp.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/sysdeps/x86_64/multiarch/wcsncmp.c b/sysdeps/x86_64/multiarch/wcsncmp.c new file mode 100644 index 0000000000..90e9a352d9 --- /dev/null +++ b/sysdeps/x86_64/multiarch/wcsncmp.c @@ -0,0 +1,31 @@ +/* Multiple versions of wcsncmp. + Copyright (C) 2018 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 wcsncmp __redirect_wcsncmp +# define __wcsncmp __redirect___wcsncmp +# include <wchar.h> +# undef wcsncmp +# undef __wcsncmp + +# define SYMBOL_NAME wcsncmp +# include "ifunc-avx2.h" + +libc_ifunc_redirected (__redirect_wcsncmp, wcsncmp, IFUNC_SELECTOR ()); +#endif |