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authorH.J. Lu <hjl.tools@gmail.com>2017-01-30 10:59:15 -0800
committerH.J. Lu <hjl.tools@gmail.com>2017-01-30 10:59:31 -0800
commit02b78ff749f0c88771713368dbb2a09b1979814f (patch)
treef65e7fc16ef78b3e4254dcf0dcdb1e98864c5576 /sysdeps/x86_64/multiarch
parentf8bf15febcaf137bbec5a61101e88cd5a9d56ca8 (diff)
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Add VZEROUPPER to memset-vec-unaligned-erms.S [BZ #21081]
Since memset-vec-unaligned-erms.S has VDUP_TO_VEC0_AND_SET_RETURN at
function entry, memset optimized for AVX2 and AVX512 will always use
ymm/zmm register. VZEROUPPER should be placed before ret in

L(stosb):
        movq    %rdx, %rcx
        movzbl  %sil, %eax
        movq    %rdi, %rdx
        rep stosb
        movq    %rdx, %rax
        ret

since it can be reached from

L(stosb_more_2x_vec):
        cmpq    $REP_STOSB_THRESHOLD, %rdx
        ja      L(stosb)

	[BZ #21081]
	* sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
	(L(stosb)): Add VZEROUPPER before ret.
Diffstat (limited to 'sysdeps/x86_64/multiarch')
-rw-r--r--sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S2
1 files changed, 2 insertions, 0 deletions
diff --git a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
index ff214f0243..704eed9a3f 100644
--- a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
+++ b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
@@ -110,6 +110,8 @@ ENTRY (__memset_erms)
 ENTRY (MEMSET_SYMBOL (__memset, erms))
 # endif
 L(stosb):
+	/* Issue vzeroupper before rep stosb.  */
+	VZEROUPPER
 	movq	%rdx, %rcx
 	movzbl	%sil, %eax
 	movq	%rdi, %rdx