glibc/sysdeps/x86_64/multiarch/ifunc-evex.h
Noah Goldstein 4fc321dc58 x86: Fix backwards Prefer_No_VZEROUPPER check in ifunc-evex.h
Add third argument to X86_ISA_CPU_FEATURES_ARCH_P macro so the runtime
CPU_FEATURES_ARCH_P check can be inverted if the
MINIMUM_X86_ISA_LEVEL is not high enough to constantly evaluate
the check.

Use this new macro to correct the backwards check in ifunc-evex.h
2022-06-27 08:35:51 -07:00

63 lines
2.2 KiB
C

/* Common definition for ifunc selection optimized with EVEX.
All versions must be listed in ifunc-impl-list.c.
Copyright (C) 2017-2022 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
<https://www.gnu.org/licenses/>. */
#include <init-arch.h>
extern __typeof (REDIRECT_NAME) OPTIMIZE (evex) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (evex_rtm) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_rtm) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
static inline void *
IFUNC_SELECTOR (void)
{
const struct cpu_features *cpu_features = __get_cpu_features ();
/* NB: The X86_ISA_* feature check macros are evaluated at
compile time. */
if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX2)
&& X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, BMI2)
&& X86_ISA_CPU_FEATURES_ARCH_P (cpu_features,
AVX_Fast_Unaligned_Load, ))
{
if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
&& X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512BW))
{
if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
return OPTIMIZE (evex_rtm);
return OPTIMIZE (evex);
}
if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
return OPTIMIZE (avx2_rtm);
if (X86_ISA_CPU_FEATURES_ARCH_P (cpu_features,
Prefer_No_VZEROUPPER, !))
return OPTIMIZE (avx2);
}
/* This is unreachable (compile time checked) if ISA level >= 3
so no need for a robust fallback here. */
return OPTIMIZE (sse2);
}