re PR c++/50793 (G++ doesn't value-initialize all members of non-trivial type in default argument)

	PR c++/50793
	* tree.c (bot_manip): Propagate AGGR_INIT_ZERO_FIRST.

From-SVN: r180227

gcc/cp/ChangeLog

+2011-10-19  Jason Merrill  <jason@redhat.com>
+
+	PR c++/50793
+	* tree.c (bot_manip): Propagate AGGR_INIT_ZERO_FIRST.
+
 2011-10-19  Roland Stigge  <stigge@antcom.de>
 
 	PR translation/49704

gcc/cp/tree.c

@@ -1879,8 +1879,12 @@ bot_manip (tree* tp, int* walk_subtrees, void* data)
       tree u;
 
       if (TREE_CODE (TREE_OPERAND (t, 1)) == AGGR_INIT_EXPR)
-	u = build_cplus_new (TREE_TYPE (t), TREE_OPERAND (t, 1),
-			     tf_warning_or_error);
+	{
+	  u = build_cplus_new (TREE_TYPE (t), TREE_OPERAND (t, 1),
+			       tf_warning_or_error);
+	  if (AGGR_INIT_ZERO_FIRST (TREE_OPERAND (t, 1)))
+	    AGGR_INIT_ZERO_FIRST (TREE_OPERAND (u, 1)) = true;
+	}
       else
 	u = build_target_expr_with_type (TREE_OPERAND (t, 1), TREE_TYPE (t),
 					 tf_warning_or_error);

gcc/testsuite/ChangeLog

+2011-10-19  Jason Merrill  <jason@redhat.com>
+
+	PR c++/50793
+	* g++.dg/init/value9.C: New.
+
 2011-10-19  Jakub Jelinek  <jakub@redhat.com>
 
 	* gcc.dg/torture/vshuf-32.inc: Add interleave permutations.

gcc/testsuite/g++.dg/init/value9.C

+// PR c++/50793
+// { dg-do run }
+
+struct NonTrivial
+{
+  NonTrivial() { }
+};
+
+struct S
+{
+  NonTrivial nt;
+  int i;
+};
+
+int f(S s)
+{
+  s.i = 0xdeadbeef;
+  return s.i;
+}
+
+int g(S s = S())
+{
+  return s.i;
+}
+
+int main()
+{
+  f(S());  // make stack dirty
+
+  if ( g() )
+    __builtin_abort();
+}