rs6000: Warn for "GCC vector passed by reference" only with -Wpsabi

	* config/rs6000/rs6000.c (rs6000_return_in_memory): Warn for
	vector return by reference only if -Wpsabi.
	(rs6000_pass_by_reference): Similarly, for argument passing.

From-SVN: r241058

gcc/ChangeLog

+2016-10-12  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	* config/rs6000/rs6000.c (rs6000_return_in_memory): Warn for
+	vector return by reference only if -Wpsabi.
+	(rs6000_pass_by_reference): Similarly, for argument passing.
+
 2016-10-12  David Malcolm  <dmalcolm@redhat.com>
 
 	* function-tests.c: Include "print-rtl.h".

gcc/config/rs6000/rs6000.c

@@ -10952,7 +10952,7 @@ rs6000_return_in_memory (const_tree type, const_tree fntype ATTRIBUTE_UNUSED)
       static bool warned_for_return_big_vectors = false;
       if (!warned_for_return_big_vectors)
 	{
-	  warning (0, "GCC vector returned by reference: "
+	  warning (OPT_Wpsabi, "GCC vector returned by reference: "
 		   "non-standard ABI extension with no compatibility guarantee");
 	  warned_for_return_big_vectors = true;
 	}
@@ -12610,7 +12610,7 @@ rs6000_pass_by_reference (cumulative_args_t cum ATTRIBUTE_UNUSED,
 	fprintf (stderr, "function_arg_pass_by_reference: synthetic vector\n");
       if (!warned_for_pass_big_vectors)
 	{
-	  warning (0, "GCC vector passed by reference: "
+	  warning (OPT_Wpsabi, "GCC vector passed by reference: "
 		   "non-standard ABI extension with no compatibility guarantee");
 	  warned_for_pass_big_vectors = true;
 	}