re PR middle-end/44878 (Build fails when compiling libstdc++)

2010-07-22  Steve Ellcey  <sje@cup.hp.com>

	PR middle-end/44878
	* stmt.c (expand_value_return):  Call promote_function_mode with
	a for_return argument of 2 when returning by reference.

From-SVN: r162423

gcc/ChangeLog

+2010-07-22  Steve Ellcey  <sje@cup.hp.com>
+
+	PR middle-end/44878
+	* stmt.c (expand_value_return):  Call promote_function_mode with
+	a for_return argument of 2 when returning by reference.
+
 2010-07-22  Dodji Seketeli  <dodji@redhat.com>
 
 	PR debug/45024

gcc/stmt.c

@@ -1595,8 +1595,11 @@ expand_value_return (rtx val)
       tree type = TREE_TYPE (decl);
       int unsignedp = TYPE_UNSIGNED (type);
       enum machine_mode old_mode = DECL_MODE (decl);
-      enum machine_mode mode = promote_function_mode (type, old_mode,
-						      &unsignedp, funtype, 1);
+      enum machine_mode mode;
+      if (DECL_BY_REFERENCE (decl))
+        mode = promote_function_mode (type, old_mode, &unsignedp, funtype, 2);
+      else
+        mode = promote_function_mode (type, old_mode, &unsignedp, funtype, 1);
 
       if (mode != old_mode)
 	val = convert_modes (mode, old_mode, val, unsignedp);