re PR c++/55419 (ICE in gimplify_init_ctor_preeval, at gimplify.c:3587)

	PR c++/55419
	PR c++/55753
	* pt.c (tsubst_copy_and_build) [TARGET_EXPR]: Don't touch
	TREE_CONSTANT.

From-SVN: r194870

gcc/cp/ChangeLog

 2013-01-03  Jason Merrill  <jason@redhat.com>
 
+	PR c++/55419
+	PR c++/55753
+	* pt.c (tsubst_copy_and_build) [TARGET_EXPR]: Don't touch
+	TREE_CONSTANT.
+
 	PR c++/55842
 	* semantics.c (trait_expr_value): Call maybe_instantiate_noexcept.
 

gcc/cp/pt.c

@@ -14333,11 +14333,9 @@ tsubst_copy_and_build (tree t,
     case TARGET_EXPR:
       /* We can get here for a constant initializer of non-dependent type.
          FIXME stop folding in cp_parser_initializer_clause.  */
-      gcc_assert (TREE_CONSTANT (t));
       {
 	tree r = get_target_expr_sfinae (RECUR (TARGET_EXPR_INITIAL (t)),
 					 complain);
-	TREE_CONSTANT (r) = true;
 	RETURN (r);
       }
 

gcc/testsuite/g++.dg/cpp0x/constexpr-ctor12.C

+// PR c++/55753
+// { dg-options -std=c++11 }
+
+template <typename Tp>
+struct C {
+  constexpr C(const Tp& r) { }
+};
+
+template <typename Tp>
+struct B {
+  B() {
+    C<double> cpl = C<double>((true ? 1.0 : C<double>()));
+  }
+};