diff -r 13588c901957 -r 9cf78a70fa4f src/hotspot/share/opto/doCall.cpp
--- a/src/hotspot/share/opto/doCall.cpp	Thu Oct 17 20:27:44 2019 +0100
+++ b/src/hotspot/share/opto/doCall.cpp	Thu Oct 17 20:53:35 2019 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -310,10 +310,12 @@
     if (call_does_dispatch && bytecode == Bytecodes::_invokeinterface) {
       ciInstanceKlass* declared_interface =
           caller->get_declared_method_holder_at_bci(bci)->as_instance_klass();
+      ciInstanceKlass* singleton = declared_interface->unique_implementor();
 
-      if (declared_interface->nof_implementors() == 1 &&
+      if (singleton != NULL &&
           (!callee->is_default_method() || callee->is_overpass()) /* CHA doesn't support default methods yet */) {
-        ciInstanceKlass* singleton = declared_interface->implementor();
+        assert(singleton != declared_interface, "not a unique implementor");
+
         ciMethod* cha_monomorphic_target =
             callee->find_monomorphic_target(caller->holder(), declared_interface, singleton);
 
@@ -700,8 +702,8 @@
         } else if (rt == T_INT || is_subword_type(rt)) {
           // Nothing.  These cases are handled in lambda form bytecode.
           assert(ct == T_INT || is_subword_type(ct), "must match: rt=%s, ct=%s", type2name(rt), type2name(ct));
-        } else if (rt == T_OBJECT || rt == T_ARRAY) {
-          assert(ct == T_OBJECT || ct == T_ARRAY, "rt=%s, ct=%s", type2name(rt), type2name(ct));
+        } else if (is_reference_type(rt)) {
+          assert(is_reference_type(ct), "rt=%s, ct=%s", type2name(rt), type2name(ct));
           if (ctype->is_loaded()) {
             const TypeOopPtr* arg_type = TypeOopPtr::make_from_klass(rtype->as_klass());
             const Type*       sig_type = TypeOopPtr::make_from_klass(ctype->as_klass());
@@ -748,7 +750,7 @@
       set_bci(iter().cur_bci()); // put it back
     }
     BasicType ct = ctype->basic_type();
-    if (ct == T_OBJECT || ct == T_ARRAY) {
+    if (is_reference_type(ct)) {
       record_profiled_return_for_speculation();
     }
   }