glibc/sysdeps/x86_64/multiarch/wcsnlen.c
H.J. Lu 1fd8c163a8 x86-64: Add ifunc-avx2.h functions with 256-bit EVEX
Update ifunc-avx2.h, strchr.c, strcmp.c, strncmp.c and wcsnlen.c to
select the function optimized with 256-bit EVEX instructions using
YMM16-YMM31 registers to avoid RTM abort with usable AVX512VL, AVX512BW
and BMI2 since VZEROUPPER isn't needed at function exit.

For strcmp/strncmp, prefer AVX2 strcmp/strncmp if Prefer_AVX2_STRCMP
is set.
2021-03-29 07:40:17 -07:00

60 lines
2.1 KiB
C

/* Multiple versions of wcsnlen.
All versions must be listed in ifunc-impl-list.c.
Copyright (C) 2017-2021 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
<https://www.gnu.org/licenses/>. */
/* Define multiple versions only for the definition in libc. */
#if IS_IN (libc)
# define __wcsnlen __redirect_wcsnlen
# include <wchar.h>
# undef __wcsnlen
# define SYMBOL_NAME wcsnlen
# include <init-arch.h>
extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (sse4_1) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (evex) attribute_hidden;
static inline void *
IFUNC_SELECTOR (void)
{
const struct cpu_features* cpu_features = __get_cpu_features ();
if (CPU_FEATURE_USABLE_P (cpu_features, AVX2)
&& CPU_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load))
{
if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
&& CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)
&& CPU_FEATURE_USABLE_P (cpu_features, BMI2))
return OPTIMIZE (evex);
if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER))
return OPTIMIZE (avx2);
}
if (CPU_FEATURE_USABLE_P (cpu_features, SSE4_1))
return OPTIMIZE (sse4_1);
return OPTIMIZE (sse2);
}
libc_ifunc_redirected (__redirect_wcsnlen, __wcsnlen, IFUNC_SELECTOR ());
weak_alias (__wcsnlen, wcsnlen);
#endif