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

src/ic/ic.h

 // 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.
 
 #ifndef V8_IC_H_
 #define V8_IC_H_
 
 #include "src/ic/ic-state.h"
 #include "src/macro-assembler.h"
 #include "src/messages.h"
@@ skipping 630 matching lines @@
 
 class CompareNilIC : public IC {
  public:
   explicit CompareNilIC(Isolate* isolate) : IC(EXTRA_CALL_FRAME, isolate) {}
 
   Handle<Object> CompareNil(Handle<Object> object);
 
   static Handle<Code> GetUninitialized();
 
   static void Clear(Address address, Code* target, Address constant_pool);
-
-  static Handle<Object> DoCompareNilSlow(Isolate* isolate, NilValue nil,
-                                         Handle<Object> object);
 };
 
 
 class ToBooleanIC : public IC {
  public:
   explicit ToBooleanIC(Isolate* isolate) : IC(EXTRA_CALL_FRAME, isolate) {}
 
   Handle<Object> ToBoolean(Handle<Object> object);
 };
 
 
 // Helper for BinaryOpIC and CompareIC.
 enum InlinedSmiCheck { ENABLE_INLINED_SMI_CHECK, DISABLE_INLINED_SMI_CHECK };
 void PatchInlinedSmiCode(Isolate* isolate, Address address,
                          InlinedSmiCheck check);
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_IC_H_