[glibc/release/2.32/master] x86-64: Require BMI2 for strchr-avx2.S [BZ #29611]

[glibc/release/2.32/master] x86-64: Require BMI2 for strchr-avx2.S [BZ #29611]

[Sunil Pandey]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=f9e29095fcc11f79a3afcb4b5dd3ce070e3d4084

commit f9e29095fcc11f79a3afcb4b5dd3ce070e3d4084
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Mon Apr 19 10:45:07 2021 -0700

    x86-64: Require BMI2 for strchr-avx2.S [BZ #29611]
    
    Since strchr-avx2.S updated by
    
    commit 1f745ecc2109890886b161d4791e1406fdfc29b8
    Author: noah <goldstein.w.n@gmail.com>
    Date:   Wed Feb 3 00:38:59 2021 -0500
    
        x86-64: Refactor and improve performance of strchr-avx2.S
    
    uses sarx:
    
    c4 e2 72 f7 c0          sarx   %ecx,%eax,%eax
    
    for strchr-avx2 family functions, require BMI2 in ifunc-impl-list.c and
    ifunc-avx2.h.
    
    This fixes BZ #29611.
    
    (cherry picked from commit 83c5b368226c34a2f0a5287df40fc290b2b34359)

Diff:
---
 sysdeps/x86_64/multiarch/ifunc-avx2.h      |  4 ++--
 sysdeps/x86_64/multiarch/ifunc-impl-list.c | 12 +++++++++---
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/sysdeps/x86_64/multiarch/ifunc-avx2.h b/sysdeps/x86_64/multiarch/ifunc-avx2.h
index f450c786f0..0d9d837488 100644
--- a/sysdeps/x86_64/multiarch/ifunc-avx2.h
+++ b/sysdeps/x86_64/multiarch/ifunc-avx2.h
@@ -30,11 +30,11 @@ IFUNC_SELECTOR (void)
   const struct cpu_features* cpu_features = __get_cpu_features ();
 
   if (CPU_FEATURE_USABLE_P (cpu_features, AVX2)
+      && CPU_FEATURE_USABLE_P (cpu_features, BMI2)
       && CPU_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load))
     {
       if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
-	  && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)
-	  && CPU_FEATURE_USABLE_P (cpu_features, BMI2))
+	  && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW))
 	return OPTIMIZE (evex);
 
       if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index 920e64241e..d4bbf61030 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -400,10 +400,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   /* Support sysdeps/x86_64/multiarch/strchr.c.  */
   IFUNC_IMPL (i, name, strchr,
 	      IFUNC_IMPL_ADD (array, i, strchr,
-			      CPU_FEATURE_USABLE (AVX2),
+			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)),
 			      __strchr_avx2)
 	      IFUNC_IMPL_ADD (array, i, strchr,
 			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)
 			       && CPU_FEATURE_USABLE (RTM)),
 			      __strchr_avx2_rtm)
 	      IFUNC_IMPL_ADD (array, i, strchr,
@@ -417,10 +419,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   /* Support sysdeps/x86_64/multiarch/strchrnul.c.  */
   IFUNC_IMPL (i, name, strchrnul,
 	      IFUNC_IMPL_ADD (array, i, strchrnul,
-			      CPU_FEATURE_USABLE (AVX2),
+			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)),
 			      __strchrnul_avx2)
 	      IFUNC_IMPL_ADD (array, i, strchrnul,
 			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)
 			       && CPU_FEATURE_USABLE (RTM)),
 			      __strchrnul_avx2_rtm)
 	      IFUNC_IMPL_ADD (array, i, strchrnul,
@@ -574,10 +578,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   /* Support sysdeps/x86_64/multiarch/wcschr.c.  */
   IFUNC_IMPL (i, name, wcschr,
 	      IFUNC_IMPL_ADD (array, i, wcschr,
-			      CPU_FEATURE_USABLE (AVX2),
+			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)),
 			      __wcschr_avx2)
 	      IFUNC_IMPL_ADD (array, i, wcschr,
 			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)
 			       && CPU_FEATURE_USABLE (RTM)),
 			      __wcschr_avx2_rtm)
 	      IFUNC_IMPL_ADD (array, i, wcschr,