--- old/src/hotspot/share/opto/library_call.cpp	2018-11-30 10:23:19.601067133 +0100
+++ new/src/hotspot/share/opto/library_call.cpp	2018-11-30 10:23:19.448068703 +0100
@@ -4464,7 +4464,7 @@
         for (MergeMemStream mms(merged_memory(), mem->as_MergeMem()); mms.next_non_empty2(); ) {
           Node* n = mms.memory();
           if (n != mms.memory2() && !(n->is_Proj() && n->in(0) == alloc->initialization())) {
-            assert(n->is_Store(), "what else?");
+            assert(n->is_Store() || n->Opcode() == Op_ShenandoahWBMemProj, "what else?");
             no_interfering_store = false;
             break;
           }
@@ -4473,7 +4473,7 @@
         for (MergeMemStream mms(merged_memory()); mms.next_non_empty(); ) {
           Node* n = mms.memory();
           if (n != mem && !(n->is_Proj() && n->in(0) == alloc->initialization())) {
-            assert(n->is_Store(), "what else?");
+            assert(n->is_Store() || n->Opcode() == Op_ShenandoahWBMemProj, "what else?");
             no_interfering_store = false;
             break;
           }