From: H.J. Lu <hjl.tools@gmail.com>
Date: Mon, 19 Apr 2021 17:45:07 +0000 (-0700)
Subject: x86-64: Require BMI2 for strchr-avx2.S [BZ #29611]
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=956cda8d9f222bba3558cf2949a35d3b477c8634;p=thirdparty%2Fglibc.git

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 --git a/sysdeps/x86_64/multiarch/ifunc-avx2.h b/sysdeps/x86_64/multiarch/ifunc-avx2.h
index 348d3d05311..14cfc48622c 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_FEATURES_ARCH_P (cpu_features, AVX2_Usable)
+      && CPU_FEATURES_CPU_P (cpu_features, BMI2)
       && CPU_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load))
     {
       if (CPU_FEATURES_ARCH_P (cpu_features, AVX512VL_Usable)
-	  && CPU_FEATURES_ARCH_P (cpu_features, AVX512BW_Usable)
-	  && CPU_FEATURES_CPU_P (cpu_features, BMI2))
+	  && CPU_FEATURES_ARCH_P (cpu_features, AVX512BW_Usable))
 	return OPTIMIZE (evex);
 
       if (CPU_FEATURES_CPU_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 1ad7a68fafe..b7c23dbec88 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -382,10 +382,12 @@ __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,
-			      HAS_ARCH_FEATURE (AVX2_Usable),
+			      (HAS_ARCH_FEATURE (AVX2_Usable)
+			       && HAS_CPU_FEATURE (BMI2)),
 			      __strchr_avx2)
 	      IFUNC_IMPL_ADD (array, i, strchr,
 			      (HAS_ARCH_FEATURE (AVX2_Usable)
+			       && HAS_CPU_FEATURE (BMI2)
 			       && HAS_CPU_FEATURE (RTM)),
 			      __strchr_avx2_rtm)
 	      IFUNC_IMPL_ADD (array, i, strchr,
@@ -399,10 +401,12 @@ __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,
-			      HAS_ARCH_FEATURE (AVX2_Usable),
+			      (HAS_ARCH_FEATURE (AVX2_Usable)
+			       && HAS_CPU_FEATURE (BMI2)),
 			      __strchrnul_avx2)
 	      IFUNC_IMPL_ADD (array, i, strchrnul,
 			      (HAS_ARCH_FEATURE (AVX2_Usable)
+			       && HAS_CPU_FEATURE (BMI2)
 			       && HAS_CPU_FEATURE (RTM)),
 			      __strchrnul_avx2_rtm)
 	      IFUNC_IMPL_ADD (array, i, strchrnul,
@@ -538,10 +542,12 @@ __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,
-			      HAS_ARCH_FEATURE (AVX2_Usable),
+			      (HAS_ARCH_FEATURE (AVX2_Usable)
+			       && HAS_CPU_FEATURE (BMI2)),
 			      __wcschr_avx2)
 	      IFUNC_IMPL_ADD (array, i, wcschr,
 			      (HAS_ARCH_FEATURE (AVX2_Usable)
+			       && HAS_CPU_FEATURE (BMI2)
 			       && HAS_CPU_FEATURE (RTM)),
 			      __wcschr_avx2_rtm)
 	      IFUNC_IMPL_ADD (array, i, wcschr,