1  /* Multiple versions of strcmp.
       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  /* Define multiple versions only for the definition in libc.  */
      21  #if IS_IN (libc)
      22  # define strcmp __redirect_strcmp
      23  # include <string.h>
      24  # undef strcmp
      25  
      26  # define SYMBOL_NAME strcmp
      27  # include <init-arch.h>
      28  
      29  extern __typeof (REDIRECT_NAME) OPTIMIZE (evex) attribute_hidden;
      30  
      31  extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
      32  extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_rtm) attribute_hidden;
      33  
      34  extern __typeof (REDIRECT_NAME) OPTIMIZE (sse42) attribute_hidden;
      35  
      36  extern __typeof (REDIRECT_NAME)
      37      OPTIMIZE (sse2_unaligned) attribute_hidden;
      38  extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
      39  
      40  
      41  
      42  static inline void *
      43  IFUNC_SELECTOR (void)
      44  {
      45    const struct cpu_features *cpu_features = __get_cpu_features ();
      46  
      47    if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX2)
      48        && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, BMI2)
      49        && X86_ISA_CPU_FEATURES_ARCH_P (cpu_features,
      50  				      AVX_Fast_Unaligned_Load, ))
      51      {
      52        if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
      53  	  && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512BW))
      54  	return OPTIMIZE (evex);
      55  
      56        if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
      57  	return OPTIMIZE (avx2_rtm);
      58  
      59        if (X86_ISA_CPU_FEATURES_ARCH_P (cpu_features,
      60  				       Prefer_No_VZEROUPPER, !))
      61  	return OPTIMIZE (avx2);
      62      }
      63  
      64    if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, SSE4_2)
      65        /* Keep this as runtime check.  Some ISA level >= 2 CPUs such as
      66  	 Tremont, Silvermont, and more check this.  */
      67        && !CPU_FEATURES_ARCH_P (cpu_features, Slow_SSE4_2))
      68      return OPTIMIZE (sse42);
      69  
      70    /* Keep this as runtime check.  The standard SSE2 version has
      71       meaningful optimizations around keeping all loads aligned in the
      72       main loop which can benefit some ISA level >= 2 CPUs.  */
      73    if (CPU_FEATURES_ARCH_P (cpu_features, Fast_Unaligned_Load))
      74      return OPTIMIZE (sse2_unaligned);
      75  
      76    return OPTIMIZE (sse2);
      77  }
      78  
      79  libc_ifunc_redirected (__redirect_strcmp, strcmp, IFUNC_SELECTOR ());
      80  
      81  # ifdef SHARED
      82  __hidden_ver1 (strcmp, __GI_strcmp, __redirect_strcmp)
      83    __attribute__ ((visibility ("hidden"))) __attribute_copy__ (strcmp);
      84  # endif
      85  #endif