[PATCH] ppc32: Reduce WARN_ON(0) to nothing

The last patch I sent means that we have WARN_ON(0) in a couple of
places when CONFIG_PREEMPT=n.  This patch makes that reduce to
nothing (rather than a conditional trap on a 0 value), and also makes
BUG_ON(0) reduce to nothing for completeness.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/asm-ppc/bug.h

@@ -24,6 +24,7 @@ struct bug_entry {
 } while (0)
 
 #define BUG_ON(x) do {							\
+	if (!__builtin_constant_p(x) || (x)) {				\
 		__asm__ __volatile__(					\
 			"1:	twnei %0,0\n"				\
 			".section __bug_table,\"a\"\n\t"		\
@@ -31,11 +32,13 @@ struct bug_entry {
 			".previous"					\
 			: : "r" (x), "i" (__LINE__), "i" (__FILE__),	\
 			    "i" (__FUNCTION__));			\
+	}								\
 } while (0)
 
-#define PAGE_BUG(page) do { BUG(); } while (0)
+#define PAGE_BUG(page)	BUG()
 
 #define WARN_ON(x) do {							\
+	if (!__builtin_constant_p(x) || (x)) {				\
 		__asm__ __volatile__(					\
 			"1:	twnei %0,0\n"				\
 			".section __bug_table,\"a\"\n\t"		\
@@ -43,6 +46,7 @@ struct bug_entry {
 			".previous"					\
 			: : "r" (x), "i" (__LINE__ + BUG_WARNING_TRAP),	\
 			    "i" (__FILE__), "i" (__FUNCTION__));	\
+	}								\
 } while (0)
 
 #endif