[PATCH] i386: Use TESTB instead of TESTL in ____longjmp_chk()

Uros Bizjak ubizjak@gmail.com
Mon Aug 18 09:19:47 GMT 2025


There is no need to use TESTL when checking the least-significant bit
with a TEST instruction. Use TESTB, which is three bytes shorter:

   f6 44 24 04 01          testb  $0x1,0x4(%esp)

vs:

   f7 44 24 04 01 00 00    testl  $0x1,0x4(%esp)
   00

for the same effect.

No functional changes intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: H.J.Lu <hjl.tools@gmail.com>
Cc: Carlos O'Donell <carlos@redhat.com>
---
 sysdeps/unix/sysv/linux/i386/____longjmp_chk.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
index e468d346d6..3e09f15662 100644
--- a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
+++ b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
@@ -67,7 +67,7 @@ ENTRY (____longjmp_chk)
 	/* Without working sigaltstack we cannot perform the test.  */
 	test	%eax, %eax
 	jne	.Lok2
-	testl	$1, 4(%esp)
+	testb	$1, 4(%esp)
 	jz	.Lfail
 
 	movl	(%esp), %eax
-- 
2.50.1



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