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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2023-11-06 17:25:42 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2023-11-21 16:15:42 -0300
commit4862d546c04bd2caf496d48335a546c0a44ad4a5 (patch)
tree3e8bbae532c3dcc5ff93dde172500467aaaaf1f5 /sysdeps/x86_64/multiarch
parenteb9291aaa6ff6af158a1436b881ef8b834559621 (diff)
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x86: Use dl-symbol-redir-ifunc.h on cpu-tunables
The dl-symbol-redir-ifunc.h redirects compiler-generated libcalls to
arch-specific memory implementations to avoid ifunc calls where it is not
yet possible. The memcmp-isa-default-impl.h aims to fix the same issue
by calling the specific memset implementation directly.

Using the memcmp symbol directly allows the compiler to inline the memset
calls (especially because _dl_tunable_set_hwcaps uses constants values),
generating better code.

Checked on x86_64-linux-gnu.

Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Diffstat (limited to 'sysdeps/x86_64/multiarch')
-rw-r--r--sysdeps/x86_64/multiarch/dl-symbol-redir-ifunc.h15
1 files changed, 15 insertions, 0 deletions
diff --git a/sysdeps/x86_64/multiarch/dl-symbol-redir-ifunc.h b/sysdeps/x86_64/multiarch/dl-symbol-redir-ifunc.h
index 3fe73ca1c3..c7d8961bb6 100644
--- a/sysdeps/x86_64/multiarch/dl-symbol-redir-ifunc.h
+++ b/sysdeps/x86_64/multiarch/dl-symbol-redir-ifunc.h
@@ -19,6 +19,8 @@
 #ifndef _DL_IFUNC_GENERIC_H
 #define _DL_IFUNC_GENERIC_H
 
+#ifndef SHARED
+
 #include <isa-level.h>
 
 #if MINIMUM_X86_ISA_LEVEL >= 4
@@ -31,4 +33,17 @@
 
 asm ("memset = " HAVE_MEMSET_IFUNC_GENERIC);
 
+
+#if MINIMUM_X86_ISA_LEVEL >= 4
+# define HAVE_MEMCMP_IFUNC_GENERIC "__memcmp_evex_movbe"
+#elif MINIMUM_X86_ISA_LEVEL == 3
+# define HAVE_MEMCMP_IFUNC_GENERIC "__memcmp_avx2_movbe"
+#else
+# define HAVE_MEMCMP_IFUNC_GENERIC "__memcmp_sse2"
+#endif
+
+asm ("memcmp = " HAVE_MEMCMP_IFUNC_GENERIC);
+
+#endif /* SHARED */
+
 #endif