Next bunch of fixes for check elimination.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index c49fa930f88f6620bfc0fe96939380a7bbd9a639..0cb42dc82dc347ab2e9dcd0bbf7edbd67ebc2701 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -1691,8 +1691,14 @@ void LCodeGen::DoConstantE(LConstantE* instr) {
 
 
 void LCodeGen::DoConstantT(LConstantT* instr) {
-  Handle<Object> value = instr->value(isolate());
-  __ Move(ToRegister(instr->result()), value);
+  Handle<Object> object = instr->value(isolate());
+  if (instr->hydrogen()->HasObjectMap()) {
+    Handle<Map> object_map = instr->hydrogen()->ObjectMap().handle();
+    CHECK(object->IsHeapObject());
+    CHECK(!object_map->is_stable() ||
+          *object_map == Handle<HeapObject>::cast(object)->map());
+  }
+  __ Move(ToRegister(instr->result()), object);
 }