glibc/sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx512.h
H.J. Lu ef8adeb041 x86: Add MathVec_Prefer_No_AVX512 to cpu-features [BZ #21967]
AVX512 functions in mathvec are used on machines with AVX512.  An AVX2
wrapper is also provided and it can be used when the AVX512 version
isn't profitable.  MathVec_Prefer_No_AVX512 is addded to cpu-features.
If glibc.tune.hwcaps=MathVec_Prefer_No_AVX512 is set in GLIBC_TUNABLES
environment variable, the AVX2 wrapper will be used.

Tested on x86-64 machines with and without AVX512.  Also verified
glibc.tune.hwcaps=MathVec_Prefer_No_AVX512 on AVX512 machine.

	[BZ #21967]
	* sysdeps/x86/cpu-features.h (bit_arch_MathVec_Prefer_No_AVX512):
	New.
	(index_arch_MathVec_Prefer_No_AVX512): Likewise.
	* sysdeps/x86/cpu-tunables.c (TUNABLE_CALLBACK (set_hwcaps)):
	Handle MathVec_Prefer_No_AVX512.
	* sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx512.h
	(IFUNC_SELECTOR): Return AVX2 version if MathVec_Prefer_No_AVX512
	is set.
2017-09-12 07:54:47 -07:00

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C

/* Common definition for libmathvec ifunc selections optimized with
AVX512.
Copyright (C) 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/>. */
#include <init-arch.h>
#undef PASTER2
#define PASTER2(x,y) x##_##y
extern void REDIRECT_NAME (void);
extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_wrapper) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (knl) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (skx) attribute_hidden;
static inline void *
IFUNC_SELECTOR (void)
{
const struct cpu_features* cpu_features = __get_cpu_features ();
if (!CPU_FEATURES_ARCH_P (cpu_features, MathVec_Prefer_No_AVX512))
{
if (CPU_FEATURES_ARCH_P (cpu_features, AVX512DQ_Usable))
return OPTIMIZE (skx);
if (CPU_FEATURES_ARCH_P (cpu_features, AVX512F_Usable))
return OPTIMIZE (knl);
}
return OPTIMIZE (avx2_wrapper);
}