Handle non-object constants in HConstant::GetMonomorphicJSObjectMap.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 1844715dbdf91c7257f964cffd1622b6ab2e9484..1c32400e24b16ec0991cc2235c3e0c50de65ce43 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -3493,7 +3493,7 @@ class HConstant FINAL : public HTemplateInstruction<0> {
 
   virtual Handle<Map> GetMonomorphicJSObjectMap() OVERRIDE {
     Handle<Object> object = object_.handle();
-    if (object->IsHeapObject()) {
+    if (!object.is_null() && object->IsHeapObject()) {
       return v8::internal::handle(HeapObject::cast(*object)->map());
     }
     return Handle<Map>();