PR c++/72457 - ICE with list-value-initialized base.

	* init.c (expand_aggr_init_1): Only handle value-init of bases.
	* constexpr.c (build_data_member_initialization): Handle multiple
	initializers for the same field.

From-SVN: r238867

gcc/cp/ChangeLog

+2016-07-29  Jason Merrill  <jason@redhat.com>
+
+	PR c++/72457
+	* init.c (expand_aggr_init_1): Only handle value-init of bases.
+	* constexpr.c (build_data_member_initialization): Handle multiple
+	initializers for the same field.
+
 2016-07-28  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/71665

gcc/cp/constexpr.c

@@ -391,7 +391,12 @@ build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec)
 	gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node);
     }
 
-  CONSTRUCTOR_APPEND_ELT (*vec, member, init);
+  /* Value-initialization can produce multiple initializers for the
+     same field; use the last one.  */
+  if (!vec_safe_is_empty (*vec) && (*vec)->last().index == member)
+    (*vec)->last().value = init;
+  else
+    CONSTRUCTOR_APPEND_ELT (*vec, member, init);
   return true;
 }
 

gcc/cp/init.c

@@ -1818,9 +1818,9 @@ expand_aggr_init_1 (tree binfo, tree true_exp, tree exp, tree init, int flags,
     }
 
   /* List-initialization from {} becomes value-initialization for non-aggregate
-     classes with default constructors.  Handle this here so protected access
-     works.  */
-  if (init && TREE_CODE (init) == TREE_LIST)
+     classes with default constructors.  Handle this here when we're
+     initializing a base, so protected access works.  */
+  if (exp != true_exp && init && TREE_CODE (init) == TREE_LIST)
     {
       tree elt = TREE_VALUE (init);
       if (DIRECT_LIST_INIT_P (elt)

gcc/testsuite/g++.dg/cpp0x/constexpr-list1.C

+// PR c++/72457
+// { dg-do compile { target c++11 } }
+
+struct A {
+  int i;
+  constexpr A(): i(0) {}
+};
+
+struct B: A { };
+
+struct C
+{
+  B b;
+  constexpr C() : b{} {}
+};