re PR c++/67364 ("accessing uninitialized member" error in constexpr context)

	PR c++/67364
	* constexpr.c (cxx_eval_store_expression): Replace
	CONSTRUCTOR_ELTS in nested CONSTRUCTORs, too.

From-SVN: r234013

gcc/cp/ChangeLog

+2016-03-05  Jason Merrill  <jason@redhat.com>
+
+	PR c++/67364
+	* constexpr.c (cxx_eval_store_expression): Replace
+	CONSTRUCTOR_ELTS in nested CONSTRUCTORs, too.
+
 2016-03-05  Patrick Palka  <ppalka@gcc.gnu.org>
 
 	PR c++/66786

gcc/cp/constexpr.c

@@ -2939,9 +2939,9 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t,
   /* Don't share a CONSTRUCTOR that might be changed later.  */
   init = unshare_expr (init);
   if (target == object)
-    {
     /* The hash table might have moved since the get earlier.  */
     valp = ctx->values->get (object);
+
   if (TREE_CODE (init) == CONSTRUCTOR)
     {
       /* An outer ctx->ctor might be pointing to *valp, so replace
@@ -2952,13 +2952,9 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t,
     }
   else
     *valp = init;
-    }
-  else
-    {
-      *valp = init;
 
   /* Update TREE_CONSTANT and TREE_SIDE_EFFECTS on enclosing
-	 CONSTRUCTORs.  */
+     CONSTRUCTORs, if any.  */
   tree elt;
   unsigned i;
   bool c = TREE_CONSTANT (init);
@@ -2971,7 +2967,6 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t,
 	if (s)
 	  TREE_SIDE_EFFECTS (elt) = true;
       }
-    }
   release_tree_vector (ctors);
 
   if (*non_constant_p)

gcc/testsuite/g++.dg/cpp0x/constexpr-aggr3.C

+// PR c++/67364
+// { dg-do compile { target c++11 } }
+
+template <typename Xn>
+struct tuple {
+  Xn storage_;
+
+  constexpr tuple(Xn const& xn)
+    : storage_(xn)
+  { }
+
+  template <typename ...dummy>
+  constexpr tuple(tuple const& other)
+    : storage_(other.storage_)
+  { }
+
+  template <typename ...dummy>
+  constexpr tuple(tuple& other)
+    : tuple(const_cast<tuple const&>(other))
+  { }
+};
+
+template <typename T>
+struct wrapper { T value; };
+
+template <typename T>
+constexpr wrapper<T> wrap(T t) { return {t}; }
+
+constexpr wrapper<tuple<int>> t = wrap(tuple<int>{2});
+static_assert(t.value.storage_ == 2, "");