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authorAurelien Jarno <aurelien@aurel32.net>2022-10-03 23:16:46 +0200
committerAurelien Jarno <aurelien@aurel32.net>2022-10-04 00:00:59 +0200
commit94b9c1b6409e34f3f0b2339f77d7ee78087422eb (patch)
tree1ceec291c8fb2c38a5adb20d95eb8e529f806457
parent67e863742d98c990b3d3b814b80042c0fa0d50a5 (diff)
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x86-64: Require BMI2 for AVX2 (raw|w)memchr implementations
The AVX2 memchr, rawmemchr and wmemchr implementations use the 'bzhi'
and 'sarx' instructions, which belongs to the BMI2 CPU feature.

Fixes: acfd088a1963 ("x86: Optimize memchr-avx2.S")
Partially resolves: BZ #29611

Reviewed-by: Noah Goldstein  <goldstein.w.n@gmail.com>
(cherry picked from commit e3e7fab7fe5186d18ca2046d99ba321c27db30ad)
-rw-r--r--sysdeps/x86_64/multiarch/ifunc-impl-list.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index e76a991dc6..81640cf006 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -41,10 +41,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   /* Support sysdeps/x86_64/multiarch/memchr.c.  */
   IFUNC_IMPL (i, name, memchr,
 	      IFUNC_IMPL_ADD (array, i, memchr,
-			      CPU_FEATURE_USABLE (AVX2),
+			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)),
 			      __memchr_avx2)
 	      IFUNC_IMPL_ADD (array, i, memchr,
 			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)
 			       && CPU_FEATURE_USABLE (RTM)),
 			      __memchr_avx2_rtm)
 	      IFUNC_IMPL_ADD (array, i, memchr,
@@ -283,10 +285,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   /* Support sysdeps/x86_64/multiarch/rawmemchr.c.  */
   IFUNC_IMPL (i, name, rawmemchr,
 	      IFUNC_IMPL_ADD (array, i, rawmemchr,
-			      CPU_FEATURE_USABLE (AVX2),
+			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)),
 			      __rawmemchr_avx2)
 	      IFUNC_IMPL_ADD (array, i, rawmemchr,
 			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)
 			       && CPU_FEATURE_USABLE (RTM)),
 			      __rawmemchr_avx2_rtm)
 	      IFUNC_IMPL_ADD (array, i, rawmemchr,
@@ -787,10 +791,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   /* Support sysdeps/x86_64/multiarch/wmemchr.c.  */
   IFUNC_IMPL (i, name, wmemchr,
 	      IFUNC_IMPL_ADD (array, i, wmemchr,
-			      CPU_FEATURE_USABLE (AVX2),
+			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)),
 			      __wmemchr_avx2)
 	      IFUNC_IMPL_ADD (array, i, wmemchr,
 			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)
 			       && CPU_FEATURE_USABLE (RTM)),
 			      __wmemchr_avx2_rtm)
 	      IFUNC_IMPL_ADD (array, i, wmemchr,