commit ebebf87d6d5668cd2d491aaf40cb2ef5e7479c02
author Adam Langley <agl@chromium.org> Fri Jun 20 12:00:00 2014 -0700
committer Adam Langley <agl@chromium.org> Fri Jun 20 13:17:33 2014 -0700
tree 7227ccd31634bd8be5ef7866c336b9976e861e90
parent 4d4bff89bb8ec345d289412f0f7f135c6e51b1a6

Add needed volatile qualifications.

Add volatile qualifications to two blocks of inline asm to stop GCC from
eliminating them as dead code.

crypto/bn/asm/x86_64-gcc.c

diff --git a/crypto/bn/asm/x86_64-gcc.c b/crypto/bn/asm/x86_64-gcc.c
index 836f001..be119aa 100644
--- a/crypto/bn/asm/x86_64-gcc.c
+++ b/crypto/bn/asm/x86_64-gcc.c
@@ -191,7 +191,8 @@
   if (n <= 0)
     return 0;
 
-  asm("	subq	%0,%0		\n" /* clear carry */
+  asm volatile (
+      "	subq	%0,%0		\n" /* clear carry */
       "	jmp	1f		\n"
       ".p2align 4			\n"
       "1:	movq	(%4,%2,8),%0	\n"
@@ -202,7 +203,7 @@
       "	sbbq	%0,%0		\n"
       : "=&r"(ret), "+c"(n), "+r"(i)
       : "r"(rp), "r"(ap), "r"(bp)
-      : "cc");
+      : "cc", "memory");
 
   return ret & 1;
 }
@@ -216,7 +217,8 @@
   if (n <= 0)
     return 0;
 
-  asm("	subq	%0,%0		\n" /* clear borrow */
+  asm volatile (
+      "	subq	%0,%0		\n" /* clear borrow */
       "	jmp	1f		\n"
       ".p2align 4			\n"
       "1:	movq	(%4,%2,8),%0	\n"
@@ -227,7 +229,7 @@
       "	sbbq	%0,%0		\n"
       : "=&r"(ret), "+c"(n), "+r"(i)
       : "r"(rp), "r"(ap), "r"(bp)
-      : "cc");
+      : "cc", "memory");
 
   return ret & 1;
 }