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-rw-r--r--sysdeps/powerpc/powerpc64/power7/memchr.S12
1 files changed, 11 insertions, 1 deletions
diff --git a/sysdeps/powerpc/powerpc64/power7/memchr.S b/sysdeps/powerpc/powerpc64/power7/memchr.S
index 03f0d7c2dd..0737100fd5 100644
--- a/sysdeps/powerpc/powerpc64/power7/memchr.S
+++ b/sysdeps/powerpc/powerpc64/power7/memchr.S
@@ -26,7 +26,17 @@ ENTRY (__memchr)
 	dcbt	0,r3
 	clrrdi  r8,r3,3
 	insrdi	r4,r4,8,48
-	add	r7,r3,r5      /* Calculate the last acceptable address.  */
+
+	/* Calculate the last acceptable address and check for possible
+	   addition overflow by using satured math:
+	   r7 = r3 + r5
+	   r7 |= -(r7 < x)  */
+	add     r7,r3,r5
+	subfc   r6,r3,r7
+	subfe   r9,r9,r9
+	extsw   r6,r9
+	or      r7,r7,r6
+
 	insrdi	r4,r4,16,32
 	cmpldi	r5,32
 	li	r9, -1