[ported from trunk r163805, adjusted to apply to linux-atomic.c
 in config/m68k/, the commit didn't add a ChangeLog entry so it
 is based on the original patch submission <mikpe@it.uu.se>]

From: "Marcus Shawcroft" <marcus dot shawcroft at arm dot com>
Subject: [PATCH, ARM] Provide __builtin_expect() hints in linux-atomic.c
Date: Wed, 1 Sep 2010 16:17:57 +0100
List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>

The out of line linux-atomic.c code does not provide __builtin_expect()
hints, this patch adds them..

gcc/

2010-09-03  Marcus Shawcroft  <marcus.shawcroft@arm.com>

	* config/arm/linux-atomic.c (__sync_val_compare_and_swap_4): Insert __builtin_expect().
	(SUBWORD_VAL_CAS): Likewise.

--- gcc-4.6.3/gcc/config/m68k/linux-atomic.c.~1~	2012-06-18 22:09:59.000000000 +0200
+++ gcc-4.6.3/gcc/config/m68k/linux-atomic.c	2012-06-18 22:11:05.000000000 +0200
@@ -160,12 +160,12 @@ __sync_val_compare_and_swap_4 (int *ptr,
     {
       actual_oldval = *ptr;
 
-      if (oldval != actual_oldval)
+      if (__builtin_expect (oldval != actual_oldval, 0))
 	return actual_oldval;
 
       fail = __kernel_cmpxchg (actual_oldval, newval, ptr);
   
-      if (!fail)
+      if (__builtin_expect (!fail, 1))
         return oldval;
     }
 }
@@ -185,7 +185,8 @@ __sync_val_compare_and_swap_4 (int *ptr,
       {									\
 	actual_oldval = *wordptr;					\
 									\
-	if (((actual_oldval & mask) >> shift) != (unsigned int) oldval)	\
+	if (__builtin_expect (((actual_oldval & mask) >> shift) !=      \
+                              (unsigned int) oldval, 0))                \
           return (actual_oldval & mask) >> shift;			\
 									\
 	actual_newval = (actual_oldval & ~mask)				\
@@ -194,7 +195,7 @@ __sync_val_compare_and_swap_4 (int *ptr,
 	fail = __kernel_cmpxchg (actual_oldval, actual_newval,		\
 				 wordptr);				\
 									\
-	if (!fail)							\
+      if (__builtin_expect (!fail, 1))                                  \
           return oldval;						\
       }									\
   }