--- a/src/hotspot/share/c1/c1_GraphBuilder.cpp	Thu Oct 17 20:27:44 2019 +0100
+++ b/src/hotspot/share/c1/c1_GraphBuilder.cpp	Thu Oct 17 20:53:35 2019 +0100
@@ -33,13 +33,13 @@
 #include "ci/ciKlass.hpp"
 #include "ci/ciMemberName.hpp"
 #include "ci/ciUtilities.inline.hpp"
+#include "compiler/compilationPolicy.hpp"
 #include "compiler/compileBroker.hpp"
 #include "interpreter/bytecode.hpp"
 #include "jfr/jfrEvents.hpp"
 #include "memory/resourceArea.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/sharedRuntime.hpp"
-#include "runtime/compilationPolicy.hpp"
 #include "runtime/vm_version.hpp"
 #include "utilities/bitMap.inline.hpp"
 
@@ -1467,11 +1467,12 @@
     call_register_finalizer();
   }
 
+  // The conditions for a memory barrier are described in Parse::do_exits().
   bool need_mem_bar = false;
   if (method()->name() == ciSymbol::object_initializer_name() &&
-      (scope()->wrote_final() || (AlwaysSafeConstructors && scope()->wrote_fields())
-                              || (support_IRIW_for_not_multiple_copy_atomic_cpu && scope()->wrote_volatile())
-     )){
+       (scope()->wrote_final() ||
+         (AlwaysSafeConstructors && scope()->wrote_fields()) ||
+         (support_IRIW_for_not_multiple_copy_atomic_cpu && scope()->wrote_volatile()))) {
     need_mem_bar = true;
   }
 
@@ -1957,12 +1958,11 @@
       // number of implementors for decl_interface is 0 or 1. If
       // it's 0 then no class implements decl_interface and there's
       // no point in inlining.
-      ciInstanceKlass* singleton = NULL;
       ciInstanceKlass* declared_interface = callee_holder;
-      if (declared_interface->nof_implementors() == 1 &&
-          (!target->is_default_method() || target->is_overpass()) /* CHA doesn't support default methods yet. */) {
-        singleton = declared_interface->implementor();
-        assert(singleton != NULL && singleton != declared_interface, "");
+      ciInstanceKlass* singleton = declared_interface->unique_implementor();
+      if (singleton != NULL &&
+          (!target->is_default_method() || target->is_overpass()) /* CHA doesn't support default methods yet. */ ) {
+        assert(singleton != declared_interface, "not a unique implementor");
         cha_monomorphic_target = target->find_monomorphic_target(calling_klass, declared_interface, singleton);
         if (cha_monomorphic_target != NULL) {
           if (cha_monomorphic_target->holder() != compilation()->env()->Object_klass()) {
@@ -3168,7 +3168,7 @@
     ciType* type = sig->type_at(i);
     BasicType basic_type = type->basic_type();
     // don't allow T_ARRAY to propagate into locals types
-    if (basic_type == T_ARRAY) basic_type = T_OBJECT;
+    if (is_reference_type(basic_type)) basic_type = T_OBJECT;
     ValueType* vt = as_ValueType(basic_type);
     state->store_local(idx, new Local(type, vt, idx, false));
     idx += type->size();