go-lang.c (go_langhook_post_options): If -fisolate-erroneous-paths was turned on…

go-lang.c (go_langhook_post_options): If -fisolate-erroneous-paths was turned on by an optimization option, turn it off.

	* go-lang.c (go_langhook_post_options): If
	-fisolate-erroneous-paths was turned on by an optimization option,
	turn it off.

From-SVN: r204459

gcc/go/ChangeLog

+2013-11-06  Ian Lance Taylor  <iant@google.com>
+
+	* go-lang.c (go_langhook_post_options): If
+	-fisolate-erroneous-paths was turned on by an optimization option,
+	turn it off.
+
 2013-10-14  Chris Manghane  <cmang@google.com>
 
 	* go-gcc.cc (Gcc_backend::address_expression): New function.

gcc/go/go-lang.c

@@ -268,6 +268,12 @@ go_langhook_post_options (const char **pfilename ATTRIBUTE_UNUSED)
   if (flag_excess_precision_cmdline == EXCESS_PRECISION_DEFAULT)
     flag_excess_precision_cmdline = EXCESS_PRECISION_STANDARD;
 
+  /* The isolate_erroneous_paths optimization can change a nil
+     dereference from a panic to a trap, so we have to disable it for
+     Go, even though it is normally enabled by -O2.  */
+  if (!global_options_set.x_flag_isolate_erroneous_paths)
+    global_options.x_flag_isolate_erroneous_paths = 0;
+
   /* Returning false means that the backend should be used.  */
   return false;
 }