alias-1.c: New testcase.

	* gcc.c-torture/execute/alias-1.c: New testcase.
	* c-common.c: Do not silently ignore -fstrict-aliasing changes.

From-SVN: r231125

gcc/ChangeLog

 2015-12-01  Jan Hubicka  <hubicka@ucw.cz>
 
+	* c-common.c (parse_optimize_options): Do not silently ignore
+	-fstrict-aliasing changes.
+
+2015-12-01  Jan Hubicka  <hubicka@ucw.cz>
+
 	* lto-streamer-out.c (hash_tree): Do not stream TYPE_ALIAS_SET.
 	* tree-streamer-out.c (pack_ts_type_common_value_fields): Do not
 	stream TYPE_ALIAS_SET.

gcc/c-family/c-common.c

@@ -9988,7 +9988,6 @@ parse_optimize_options (tree args, bool attr_p)
   bool ret = true;
   unsigned opt_argc;
   unsigned i;
-  int saved_flag_strict_aliasing;
   const char **opt_argv;
   struct cl_decoded_option *decoded_options;
   unsigned int decoded_options_count;
@@ -10081,8 +10080,6 @@ parse_optimize_options (tree args, bool attr_p)
   for (i = 1; i < opt_argc; i++)
     opt_argv[i] = (*optimize_args)[i];
 
-  saved_flag_strict_aliasing = flag_strict_aliasing;
-
   /* Now parse the options.  */
   decode_cmdline_options_to_array_default_mask (opt_argc, opt_argv,
 						&decoded_options,
@@ -10093,9 +10090,6 @@ parse_optimize_options (tree args, bool attr_p)
 
   targetm.override_options_after_change();
 
-  /* Don't allow changing -fstrict-aliasing.  */
-  flag_strict_aliasing = saved_flag_strict_aliasing;
-
   optimize_args->truncate (0);
   return ret;
 }

gcc/testsuite/ChangeLog

+2015-12-01  Jan Hubicka  <hubicka@ucw.cz>
+
+	* gcc.c-torture/execute/alias-1.c: New testcase.
+
 2015-12-01  Marek Polacek  <polacek@redhat.com>
 
 	PR tree-optimization/64769

gcc/testsuite/gcc.c-torture/execute/alias-1.c

+int val;
+
+int *ptr = &val;
+float *ptr2 = &val;
+
+__attribute__((optimize ("-fno-strict-aliasing")))
+typepun ()
+{
+  *ptr2=0;
+}
+
+main()
+{
+  *ptr=1;
+  typepun ();
+  if (*ptr)
+    __builtin_abort ();
+}
+