Undefined is not a literal.

src/ast.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 335 matching lines @@
 
   // True iff the expression is a literal represented as a smi.
   bool IsSmiLiteral();
 
   // True iff the expression is a string literal.
   bool IsStringLiteral();
 
   // True iff the expression is the null literal.
   bool IsNullLiteral();
 
-  // True iff the expression is the undefined literal.
-  bool IsUndefinedLiteral();
+  // True if we can prove that the expression is the undefined literal.
+  bool IsUndefinedLiteral(Isolate* isolate);
 
   // Expression type bounds
   Bounds bounds() { return bounds_; }
   void set_bounds(Bounds bounds) { bounds_ = bounds; }
 
   // Type feedback information for assignments and properties.
   virtual bool IsMonomorphic() {
     UNREACHABLE();
     return false;
   }
@@ skipping 1619 matching lines @@
   Expression* right() const { return right_; }
   virtual int position() const { return pos_; }
 
   // Type feedback information.
   TypeFeedbackId CompareOperationFeedbackId() const { return reuse(id()); }
   Handle<Type> combined_type() const { return combined_type_; }
   void set_combined_type(Handle<Type> type) { combined_type_ = type; }
 
   // Match special cases.
   bool IsLiteralCompareTypeof(Expression** expr, Handle<String>* check);
-  bool IsLiteralCompareUndefined(Expression** expr);
+  bool IsLiteralCompareUndefined(Expression** expr, Isolate* isolate);
   bool IsLiteralCompareNull(Expression** expr);
 
  protected:
   CompareOperation(Isolate* isolate,
                    Token::Value op,
                    Expression* left,
                    Expression* right,
                    int pos)
       : Expression(isolate),
         op_(op),
@@ skipping 1201 matching lines @@
  private:
   Isolate* isolate_;
   Zone* zone_;
   Visitor visitor_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_