commit 67e863742d98c990b3d3b814b80042c0fa0d50a5
Author: Aurelien Jarno <aurelien@aurel32.net>
Date:   Mon Oct 3 23:16:46 2022 +0200

    x86-64: Require BMI2 for AVX2 wcs(n)cmp implementations
    
    The AVX2 wcs(n)cmp implementations use the 'bzhi' instruction, which
    belongs to the BMI2 CPU feature.
    
    NB: It also uses the 'tzcnt' BMI1 instruction, but it is executed as BSF
    as BSF if the CPU doesn't support TZCNT, and produces the same result
    for non-zero input.
    
    Partially fixes: b77b06e0e296 ("x86: Optimize strcmp-avx2.S")
    Partially resolves: BZ #29611
    
    Reviewed-by: Noah Goldstein  <goldstein.w.n@gmail.com>
    (cherry picked from commit f31a5a884ed84bd37032729d4d1eb9d06c9f3c29)

diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index 34d5f6efe5421014..e76a991dc671c1a9 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -693,10 +693,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   /* Support sysdeps/x86_64/multiarch/wcscmp.c.  */
   IFUNC_IMPL (i, name, wcscmp,
 	      IFUNC_IMPL_ADD (array, i, wcscmp,
-			      CPU_FEATURE_USABLE (AVX2),
+			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)),
 			      __wcscmp_avx2)
 	      IFUNC_IMPL_ADD (array, i, wcscmp,
 			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)
 			       && CPU_FEATURE_USABLE (RTM)),
 			      __wcscmp_avx2_rtm)
 	      IFUNC_IMPL_ADD (array, i, wcscmp,
@@ -709,10 +711,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   /* Support sysdeps/x86_64/multiarch/wcsncmp.c.  */
   IFUNC_IMPL (i, name, wcsncmp,
 	      IFUNC_IMPL_ADD (array, i, wcsncmp,
-			      CPU_FEATURE_USABLE (AVX2),
+			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)),
 			      __wcsncmp_avx2)
 	      IFUNC_IMPL_ADD (array, i, wcsncmp,
 			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)
 			       && CPU_FEATURE_USABLE (RTM)),
 			      __wcsncmp_avx2_rtm)
 	      IFUNC_IMPL_ADD (array, i, wcsncmp,