--- a/src/hotspot/share/oops/instanceRefKlass.inline.hpp	Fri Aug 24 09:38:11 2018 +0200
+++ b/src/hotspot/share/oops/instanceRefKlass.inline.hpp	Fri Jul 06 16:04:19 2018 +0200
@@ -183,8 +183,13 @@
   T* discovered_addr = (T*) java_lang_ref_Reference::discovered_addr_raw(obj);
 
   log_develop_trace(gc, ref)("InstanceRefKlass %s for obj " PTR_FORMAT, s, p2i(obj));
-  log_develop_trace(gc, ref)("     referent_addr/* " PTR_FORMAT " / " PTR_FORMAT,
-      p2i(referent_addr), p2i((oop)HeapAccess<ON_UNKNOWN_OOP_REF | AS_NO_KEEPALIVE>::oop_load_at(obj, java_lang_ref_Reference::referent_offset)));
+  if (java_lang_ref_Reference::is_phantom(obj)) {
+    log_develop_trace(gc, ref)("     referent_addr/* " PTR_FORMAT " / " PTR_FORMAT,
+                               p2i(referent_addr), p2i((oop)HeapAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE>::oop_load(referent_addr)));
+  } else {
+    log_develop_trace(gc, ref)("     referent_addr/* " PTR_FORMAT " / " PTR_FORMAT,
+                               p2i(referent_addr), p2i((oop)HeapAccess<ON_WEAK_OOP_REF | AS_NO_KEEPALIVE>::oop_load(referent_addr)));
+  }
   log_develop_trace(gc, ref)("     discovered_addr/* " PTR_FORMAT " / " PTR_FORMAT,
       p2i(discovered_addr), p2i((oop)HeapAccess<AS_NO_KEEPALIVE>::oop_load(discovered_addr)));
 }