optabs.c (expand_atomic_compare_and_swap): Allow expander to fail.

2014-02-07  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>

	* optabs.c (expand_atomic_compare_and_swap): Allow expander to
	fail.

From-SVN: r207599

gcc/ChangeLog

+2014-02-07  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>
+
+	* optabs.c (expand_atomic_compare_and_swap): Allow expander to
+	fail.
+
 2014-02-07  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/60092

gcc/optabs.c

@@ -7383,12 +7383,13 @@ expand_atomic_compare_and_swap (rtx *ptarget_bool, rtx *ptarget_oval,
       create_integer_operand (&ops[5], is_weak);
       create_integer_operand (&ops[6], succ_model);
       create_integer_operand (&ops[7], fail_model);
-      expand_insn (icode, 8, ops);
-
-      /* Return success/failure.  */
-      target_bool = ops[0].value;
-      target_oval = ops[1].value;
-      goto success;
+      if (maybe_expand_insn (icode, 8, ops))
+	{
+	  /* Return success/failure.  */
+	  target_bool = ops[0].value;
+	  target_oval = ops[1].value;
+	  goto success;
+	}
     }
 
   /* Otherwise fall back to the original __sync_val_compare_and_swap