re PR c++/48834 (-fno-exceptions causes wrong code generation on C++ code)

	PR c++/48834
	* tree.c (build_vec_init_expr): Set TREE_SIDE_EFFECTS.
	Protect an explicit target.

From-SVN: r173272

gcc/cp/ChangeLog

 2011-05-02  Jason Merrill  <jason@redhat.com>
 
+	PR c++/48834
+	* tree.c (build_vec_init_expr): Set TREE_SIDE_EFFECTS.
+	Protect an explicit target.
+
 	PR c++/48446
 	* decl.c (stabilize_save_expr_r, stabilize_vla_size): New.
 	(compute_array_index_type): Revert earlier 48446 changes.

gcc/cp/tree.c

@@ -564,6 +564,7 @@ build_vec_init_expr (tree target, tree init, tree nelts,
     elt_init = build_vec_init_elt (type, init, complain);
 
   init = build3 (VEC_INIT_EXPR, type, slot, init, nelts);
+  TREE_SIDE_EFFECTS (init) = true;
   SET_EXPR_LOCATION (init, input_location);
 
   if (cxx_dialect >= cxx0x
@@ -571,7 +572,11 @@ build_vec_init_expr (tree target, tree init, tree nelts,
     VEC_INIT_EXPR_IS_CONSTEXPR (init) = true;
   VEC_INIT_EXPR_VALUE_INIT (init) = value_init;
 
-  if (slot != target)
+  if (slot == target)
+    /* If we specified what array we're initializing, make sure
+       we don't override that in cp_gimplify_init_expr.  */
+    init = cp_build_compound_expr (init, slot, complain);
+  else
     {
       init = build_target_expr (slot, init, complain);
       TARGET_EXPR_IMPLICIT_P (init) = 1;

gcc/testsuite/ChangeLog

+2011-05-02  Jason Merrill  <jason@redhat.com>
+
+	* g++.dg/init/new31.C: New.
+
 2011-05-02  Simon Martin  <simartin@users.sourceforge.net>
 
 	PR c/35445

gcc/testsuite/g++.dg/init/new31.C

+// PR c++/48834
+// { dg-options -Wuninitialized }
+// { dg-do run }
+
+struct S
+{
+  S ():i (0)
+  {
+  }
+  int i;
+};
+
+int
+main ()
+{
+  S *s = new S[2];
+  return 0;
+}