[glibc/release/2.35/master] x86-64: Fix SSE2 memcmp and SSSE3 memmove for x32

[glibc/release/2.35/master] x86-64: Fix SSE2 memcmp and SSSE3 memmove for x32

[Sunil Pandey]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=bc35e22be4ca69f3e2c2e1403ac30d028e092a38

commit bc35e22be4ca69f3e2c2e1403ac30d028e092a38
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Apr 22 10:53:13 2022 -0700

    x86-64: Fix SSE2 memcmp and SSSE3 memmove for x32
    
    Clear the upper 32 bits in RDX (memory size) for x32 to fix
    
    FAIL: string/tst-size_t-memcmp
    FAIL: string/tst-size_t-memcmp-2
    FAIL: string/tst-size_t-memcpy
    FAIL: wcsmbs/tst-size_t-wmemcmp
    
    on x32 introduced by
    
    8804157ad9 x86: Optimize memcmp SSE2 in memcmp.S
    26b2478322 x86: Reduce code size of mem{move|pcpy|cpy}-ssse3
    
    Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
    (cherry picked from commit 8ea20ee5f6145de4bff9481d3e09ac36ba9df8f3)

Diff:
---
 sysdeps/x86_64/memcmp.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sysdeps/x86_64/memcmp.S b/sysdeps/x86_64/memcmp.S
index b153694048..5718a7da86 100644
--- a/sysdeps/x86_64/memcmp.S
+++ b/sysdeps/x86_64/memcmp.S
@@ -46,6 +46,10 @@
 
 	.text
 ENTRY(MEMCMP)
+# ifdef __ILP32__
+	/* Clear the upper 32 bits.  */
+	movl	%edx, %edx
+# endif
 #ifdef USE_AS_WMEMCMP
 	/* Use 0xffff to test for mismatches on pmovmskb bitmask. Store
 	   in ecx for code size. This is preferable to using `incw` as