diff -r f6005102c6ef -r af52abc1f61e src/hotspot/share/gc/z/c2/zBarrierSetC2.cpp
--- a/src/hotspot/share/gc/z/c2/zBarrierSetC2.cpp	Tue Dec 04 21:13:45 2018 -0800
+++ b/src/hotspot/share/gc/z/c2/zBarrierSetC2.cpp	Fri Nov 30 15:22:44 2018 +0100
@@ -995,13 +995,12 @@
 }
 
 bool ZBarrierSetC2::expand_barriers(Compile* C, PhaseIterGVN& igvn) const {
-  PhaseMacroExpand macro(igvn);
   ZBarrierSetC2State* s = state();
   if (s->load_barrier_count() > 0) {
+    PhaseMacroExpand macro(igvn);
 #ifdef ASSERT
     verify_gc_barriers(false);
 #endif
-    igvn.set_delay_transform(true);
     int skipped = 0;
     while (s->load_barrier_count() > skipped) {
       int load_barrier_count = s->load_barrier_count();