PR c++/70709 - zero-length array member

	* class.c (walk_subobject_offsets): Handle 0-length array.

From-SVN: r238687

gcc/cp/ChangeLog

 2016-07-23  Jason Merrill  <jason@redhat.com>
 
+	PR c++/70709
+	* class.c (walk_subobject_offsets): Handle 0-length array.
+
 	PR c++/70778
 	* pt.c (tsubst): Also substitute into the template of a
 	BOUND_TEMPLATE_TEMPLATE_PARM.

gcc/cp/class.c

@@ -4175,7 +4175,8 @@ walk_subobject_offsets (tree type,
       /* Avoid recursing into objects that are not interesting.  */
       if (!CLASS_TYPE_P (element_type)
 	  || !CLASSTYPE_CONTAINS_EMPTY_CLASS_P (element_type)
-	  || !domain)
+	  || !domain
+	  || integer_minus_onep (TYPE_MAX_VALUE (domain)))
 	return 0;
 
       /* Step through each of the elements in the array.  */

gcc/testsuite/g++.dg/ext/array3.C

+// PR c++/70709
+// { dg-options "" }
+
+struct A
+{
+  A (int);
+};
+
+struct B
+{
+  B () {} 
+  A a[0];
+};
+
+struct C
+{
+  C () {} 
+  B a[0];
+};