re PR c++/46688 (g++ requires a function declaration when it should not)

	PR c++/46688
	* tree.c (build_vec_init_expr): Handle flexible array
	properly.

From-SVN: r168782

gcc/cp/ChangeLog

+2011-01-14  Jason Merrill  <jason@redhat.com>
+
+	PR c++/46688
+	* tree.c (build_vec_init_expr): Handle flexible array
+	properly.
+
 2011-01-13  Kai Tietz  <kai.tietz@onevision.com>
 
 	PR c++/47213

gcc/cp/tree.c

@@ -474,7 +474,12 @@ build_vec_init_expr (tree type, tree init)
      what functions are needed.  Here we assume that init is either
      NULL_TREE, void_type_node (indicating value-initialization), or
      another array to copy.  */
-  if (init == void_type_node)
+  if (integer_zerop (array_type_nelts_total (type)))
+    {
+      /* No actual initialization to do.  */;
+      init = NULL_TREE;
+    }
+  else if (init == void_type_node)
     {
       elt_init = build_value_init (inner_type, tf_warning_or_error);
       value_init = true;

gcc/testsuite/ChangeLog

+2011-01-14  Jason Merrill  <jason@redhat.com>
+
+	* g++.dg/ext/flexary2.C: New.
+
 2011-01-14  Richard Guenther  <rguenther@suse.de>
 
 	PR middle-end/47281

gcc/testsuite/g++.dg/ext/flexary2.C

+// PR c++/46688
+// { dg-options "" }
+
+struct A {
+   A(int);
+};
+
+struct B {
+   B() {}
+   A a[];
+};