glibc/sysdeps/x86_64/multiarch/ifunc-memmove.h

/* Common definition for memcpy, mempcpy and memmove implementation.
   All versions must be listed in ifunc-impl-list.c.
   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>

extern __typeof (REDIRECT_NAME) OPTIMIZE (erms) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2_unaligned)
  attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2_unaligned_erms)
  attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (ssse3) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (ssse3_back) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (avx_unaligned) attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (avx_unaligned_erms)
  attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (avx512_unaligned)
  attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (avx512_unaligned_erms)
  attribute_hidden;
extern __typeof (REDIRECT_NAME) OPTIMIZE (avx512_no_vzeroupper)
  attribute_hidden;

static inline void *
IFUNC_SELECTOR (void)
{
  const struct cpu_features* cpu_features = __get_cpu_features ();

  if (CPU_FEATURES_ARCH_P (cpu_features, Prefer_ERMS))
    return OPTIMIZE (erms);

  if (CPU_FEATURES_ARCH_P (cpu_features, AVX512F_Usable)
      && !CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_AVX512))
    {
      if (CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER))
	return OPTIMIZE (avx512_no_vzeroupper);

      if (CPU_FEATURES_CPU_P (cpu_features, ERMS))
	return OPTIMIZE (avx512_unaligned_erms);

      return OPTIMIZE (avx512_unaligned);
    }

  if (CPU_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load))
    {
      if (CPU_FEATURES_CPU_P (cpu_features, ERMS))
	return OPTIMIZE (avx_unaligned_erms);

      return OPTIMIZE (avx_unaligned);
    }

  if (!CPU_FEATURES_CPU_P (cpu_features, SSSE3)
      || CPU_FEATURES_ARCH_P (cpu_features, Fast_Unaligned_Copy))
    {
      if (CPU_FEATURES_CPU_P (cpu_features, ERMS))
	return OPTIMIZE (sse2_unaligned_erms);

      return OPTIMIZE (sse2_unaligned);
    }

  if (CPU_FEATURES_ARCH_P (cpu_features, Fast_Copy_Backward))
    return OPTIMIZE (ssse3_back);

  return OPTIMIZE (ssse3);
}