--- old/src/hotspot/share/gc/z/zBarrierSet.cpp	2019-03-11 14:25:55.414355304 +0100
+++ new/src/hotspot/share/gc/z/zBarrierSet.cpp	2019-03-11 14:25:55.186355307 +0100
@@ -66,6 +66,7 @@
   assert((decorators & AS_NO_KEEPALIVE) == 0, "Unexpected decorator");
   //assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "Unexpected decorator");
 
+  assert(type != T_VALUETYPE, "Not supported yet");
   if (type == T_OBJECT || type == T_ARRAY) {
     assert((decorators & (IN_HEAP | IN_NATIVE)) != 0, "Where is reference?");
     // Barrier needed even when IN_NATIVE, to allow concurrent scanning.