[backport from gcc-4.8/trunk r195186 <mikpe@it.uu.se>]

gcc/

2013-01-15  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/48766
	* opts.c (common_handle_option): For -fwrapv disable -ftrapv, for
	-ftrapv disable -fwrapv.

--- gcc-4.6.3/gcc/opts.c.~1~	2011-02-17 23:51:57.000000000 +0100
+++ gcc-4.6.3/gcc/opts.c	2013-01-20 12:57:24.033682399 +0100
@@ -1696,6 +1696,16 @@ common_handle_option (struct gcc_options
       /* No-op. Used by the driver and passed to us because it starts with f.*/
       break;
 
+    case OPT_fwrapv:
+      if (value)
+	opts->x_flag_trapv = 0;
+      break;
+
+    case OPT_ftrapv:
+      if (value)
+	opts->x_flag_wrapv = 0;
+      break;
+
     default:
       /* If the flag was handled in a standard way, assume the lack of
 	 processing here is intentional.  */