From ec93c3ed238c591b0167a8d7f08772308f4e7bd5 Mon Sep 17 00:00:00 2001
From: Mikael Ronstrom <mikael@mysql.com>
Date: Mon, 21 Dec 2009 14:08:11 +0100
Subject: [PATCH] Force use of c-register in CAS instruction on x86-32 bit
 architecture, b-register used for push and pop, so don't want to give compile
 the chance to choose the wrong register

---
 include/atomic/x86-gcc.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/atomic/x86-gcc.h b/include/atomic/x86-gcc.h
index 32839e0a67d..77c32f8d70c 100644
--- a/include/atomic/x86-gcc.h
+++ b/include/atomic/x86-gcc.h
@@ -108,7 +108,7 @@
   int32 ebx=(set & 0xFFFFFFFF), ecx=(set >> 32);                \
   asm volatile ("push %%ebx; movl %3, %%ebx;"                   \
                 LOCK_prefix "; cmpxchg8b %0; setz %2; pop %%ebx"\
-               : "+m" (*a), "+A" (*cmp), "=q" (ret)             \
+               : "+m" (*a), "+A" (*cmp), "=c" (ret)             \
                :"m" (ebx), "c" (ecx))
 #endif