class.c (is_really_empty_class): A zero-length array is empty.

	* class.c (is_really_empty_class): A zero-length array is empty.
	An unnamed bit-field doesn't make a class non-empty.

From-SVN: r234916

gcc/cp/ChangeLog

+2016-04-12  Jason Merrill  <jason@redhat.com>
+
+	* class.c (is_really_empty_class): A zero-length array is empty.
+	An unnamed bit-field doesn't make a class non-empty.
+
 2016-04-12  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/68722

gcc/cp/class.c

@@ -8406,12 +8406,15 @@ is_really_empty_class (tree type)
       for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
 	if (TREE_CODE (field) == FIELD_DECL
 	    && !DECL_ARTIFICIAL (field)
+	    /* An unnamed bit-field is not a data member.  */
+	    && (DECL_NAME (field) || !DECL_C_BIT_FIELD (field))
 	    && !is_really_empty_class (TREE_TYPE (field)))
 	  return false;
       return true;
     }
   else if (TREE_CODE (type) == ARRAY_TYPE)
-    return is_really_empty_class (TREE_TYPE (type));
+    return (integer_zerop (array_type_nelts_top (type))
+	    || is_really_empty_class (TREE_TYPE (type)));
   return false;
 }