Drop null/undefined check if we already check for IsUndetectable in BuildCompareNil

src/ic/ic.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/ic/ic.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/arguments.h"
 #include "src/base/bits.h"
@@ skipping 2720 matching lines @@
                         HydrogenCodeStub::UNINITIALIZED);
   stub.ClearState();
 
   Code* code = NULL;
   CHECK(stub.FindCodeInCache(&code));
 
   SetTargetAtAddress(address, code, constant_pool);
 }
 
 
-Handle<Object> CompareNilIC::DoCompareNilSlow(Isolate* isolate, NilValue nil,
-                                              Handle<Object> object) {
-  if (object->IsNull() || object->IsUndefined()) {
-    return isolate->factory()->true_value();
-  }
-  return isolate->factory()->ToBoolean(object->IsUndetectableObject());
-}
-
-
 Handle<Object> CompareNilIC::CompareNil(Handle<Object> object) {
   ExtraICState extra_ic_state = target()->extra_ic_state();
 
   CompareNilICStub stub(isolate(), extra_ic_state);
 
   // Extract the current supported types from the patched IC and calculate what
   // types must be supported as a result of the miss.
   bool already_monomorphic = stub.IsMonomorphic();
 
   stub.UpdateStatus(object);
 
-  NilValue nil = stub.nil_value();
-
   // Find or create the specialized stub to support the new set of types.
   Handle<Code> code;
   if (stub.IsMonomorphic()) {
     Handle<Map> monomorphic_map(already_monomorphic && FirstTargetMap() != NULL
                                     ? FirstTargetMap()
                                     : HeapObject::cast(*object)->map());
     code = PropertyICCompiler::ComputeCompareNil(monomorphic_map, &stub);
   } else {
     code = stub.GetCode();
   }
   set_target(*code);
-  return DoCompareNilSlow(isolate(), nil, object);
+  return isolate()->factory()->ToBoolean(object->IsUndetectableObject());
 }
 
 
 RUNTIME_FUNCTION(Runtime_CompareNilIC_Miss) {
   TimerEventScope<TimerEventIcMiss> timer(isolate);
   HandleScope scope(isolate);
   Handle<Object> object = args.at<Object>(0);
   CompareNilIC ic(isolate);
   return *ic.CompareNil(object);
 }
@@ skipping 191 matching lines @@
     KeyedLoadICNexus nexus(vector, vector_slot);
     KeyedLoadIC ic(IC::EXTRA_CALL_FRAME, isolate, &nexus);
     ic.UpdateState(receiver, key);
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
   }
 
   return *result;
 }
 }  // namespace internal
 }  // namespace v8