1  /* Common definition for ifunc selections optimized with SSE2 and SSE4.2.
       2     All versions must be listed in ifunc-impl-list.c.
       3     Copyright (C) 2017-2023 Free Software Foundation, Inc.
       4     This file is part of the GNU C Library.
       5  
       6     The GNU C Library is free software; you can redistribute it and/or
       7     modify it under the terms of the GNU Lesser General Public
       8     License as published by the Free Software Foundation; either
       9     version 2.1 of the License, or (at your option) any later version.
      10  
      11     The GNU C Library is distributed in the hope that it will be useful,
      12     but WITHOUT ANY WARRANTY; without even the implied warranty of
      13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      14     Lesser General Public License for more details.
      15  
      16     You should have received a copy of the GNU Lesser General Public
      17     License along with the GNU C Library; if not, see
      18     <https://www.gnu.org/licenses/>.  */
      19  
      20  #include <init-arch.h>
      21  
      22  extern __typeof (REDIRECT_NAME) OPTIMIZE (generic) attribute_hidden;
      23  extern __typeof (REDIRECT_NAME) OPTIMIZE (sse42) attribute_hidden;
      24  
      25  static inline void *
      26  IFUNC_SELECTOR (void)
      27  {
      28    const struct cpu_features* cpu_features = __get_cpu_features ();
      29  
      30    /* This function uses the `pcmpstri` sse4.2 instruction which can be
      31       slow on some CPUs.  This normally would be guarded by a
      32       Slow_SSE4_2 check, but since there is no other optimized
      33       implementation its best to keep it regardless.  If an optimized
      34       fallback is added add a X86_ISA_CPU_FEATURE_ARCH_P (cpu_features,
      35       Slow_SSE4_2) check.  */
      36    if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, SSE4_2))
      37      return OPTIMIZE (sse42);
      38  
      39    return OPTIMIZE (generic);
      40  }