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From: Aurelien Jarno <aurel32@sourceware.org>
To: glibc-cvs@sourceware.org
Subject: [glibc/release/2.34/master] x86-64: Require BMI2 for AVX2 (raw|w)memchr implementations
Date: Mon,  3 Oct 2022 22:02:31 +0000 (GMT)	[thread overview]
Message-ID: <20221003220231.E9E28385416E@sourceware.org> (raw)

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=94b9c1b6409e34f3f0b2339f77d7ee78087422eb

commit 94b9c1b6409e34f3f0b2339f77d7ee78087422eb
Author: Aurelien Jarno <aurelien@aurel32.net>
Date:   Mon Oct 3 23:16:46 2022 +0200

    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)

Diff:
---
 sysdeps/x86_64/multiarch/ifunc-impl-list.c | 12 +++++++++---
 1 file 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,

                 reply	other threads:[~2022-10-03 22:02 UTC|newest]

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