--- a/src/hotspot/share/gc/z/zBarrierSet.inline.hpp	Tue Jul 02 12:24:26 2019 +0200
+++ b/src/hotspot/share/gc/z/zBarrierSet.inline.hpp	Tue Jul 02 12:24:28 2019 +0200
@@ -62,6 +62,7 @@
     } else if (HasDecorator<decorators, ON_WEAK_OOP_REF>::value) {
       return ZBarrier::weak_load_barrier_on_weak_oop_field_preloaded(addr, o);
     } else {
+      assert((HasDecorator<decorators, ON_PHANTOM_OOP_REF>::value), "Must be");
       return ZBarrier::weak_load_barrier_on_phantom_oop_field_preloaded(addr, o);
     }
   } else {
@@ -70,6 +71,7 @@
     } else if (HasDecorator<decorators, ON_WEAK_OOP_REF>::value) {
       return ZBarrier::load_barrier_on_weak_oop_field_preloaded(addr, o);
     } else {
+      assert((HasDecorator<decorators, ON_PHANTOM_OOP_REF>::value), "Must be");
       return ZBarrier::load_barrier_on_phantom_oop_field_preloaded(addr, o);
     }
   }
@@ -89,6 +91,7 @@
     } else if (decorators_known_strength & ON_WEAK_OOP_REF) {
       return ZBarrier::weak_load_barrier_on_weak_oop_field_preloaded(addr, o);
     } else {
+      assert(decorators_known_strength & ON_PHANTOM_OOP_REF, "Must be");
       return ZBarrier::weak_load_barrier_on_phantom_oop_field_preloaded(addr, o);
     }
   } else {
@@ -97,6 +100,7 @@
     } else if (decorators_known_strength & ON_WEAK_OOP_REF) {
       return ZBarrier::load_barrier_on_weak_oop_field_preloaded(addr, o);
     } else {
+      assert(decorators_known_strength & ON_PHANTOM_OOP_REF, "Must be");
       return ZBarrier::load_barrier_on_phantom_oop_field_preloaded(addr, o);
     }
   }