glibc/sysdeps/x86_64/multiarch/ifunc-memcmp.h
H.J. Lu 7ebba91361 x86-64: Add AVX optimized string/memory functions for RTM
Since VZEROUPPER triggers RTM abort while VZEROALL won't, select AVX
optimized string/memory functions with

	xtest
	jz	1f
	vzeroall
	ret
1:
	vzeroupper
	ret

at function exit on processors with usable RTM, but without 256-bit EVEX
instructions to avoid VZEROUPPER inside a transactionally executing RTM
region.
2021-03-29 07:40:17 -07:00

57 lines
2.1 KiB
C

/* Common definition for memcmp/wmemcmp ifunc selections.
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/>. */
# include <init-arch.h>
extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (ssse3) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (sse4_1) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_movbe) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_movbe_rtm) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (evex_movbe) 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_FEATURE_USABLE_P (cpu_features, MOVBE)
&& 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))
return OPTIMIZE (evex_movbe);
if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
return OPTIMIZE (avx2_movbe_rtm);
if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER))
return OPTIMIZE (avx2_movbe);
}
if (CPU_FEATURE_USABLE_P (cpu_features, SSE4_1))
return OPTIMIZE (sse4_1);
if (CPU_FEATURE_USABLE_P (cpu_features, SSSE3))
return OPTIMIZE (ssse3);
return OPTIMIZE (sse2);
}