From: Daniel Santos <daniel.santos@pobox.com>
Date: Wed, 20 Feb 2013 02:13:30 +0000 (+1100)
Subject: bug.h: Prevent double evaulation of in BUILD_BUG_ON
X-Git-Tag: next-20130220~1^2~682
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3a27efbe278b4a0e54e9c2a6f1f7c27c1e1327af;p=karo-tx-linux.git

bug.h: Prevent double evaulation of in BUILD_BUG_ON

When calling BUILD_BUG_ON in an optimized build using gcc 4.3 and later,
the condition will be evaulated twice, possibily with side-effects.  This
patch eliminates that error.

Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Joe Perches <joe@perches.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/include/linux/bug.h b/include/linux/bug.h
index 27d404f91b3e..0d75762cd415 100644
--- a/include/linux/bug.h
+++ b/include/linux/bug.h
@@ -59,8 +59,9 @@ struct pt_regs;
 extern int __build_bug_on_failed;
 #define BUILD_BUG_ON(condition)					\
 	do {							\
-		((void)sizeof(char[1 - 2*!!(condition)]));	\
-		if (condition) __build_bug_on_failed = 1;	\
+		bool __cond = !!(condition);			\
+		((void)sizeof(char[1 - 2 * __cond]));		\
+		if (__cond) __build_bug_on_failed = 1;		\
 	} while(0)
 #endif