Better codegen for '<expression> === void <literal>'.

src/hydrogen.h

 // Copyright 2011 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 863 matching lines @@
   void HandleCompoundAssignment(Assignment* expr);
   void HandlePolymorphicStoreNamedField(Assignment* expr,
                                         HValue* object,
                                         HValue* value,
                                         ZoneMapList* types,
                                         Handle<String> name);
   void HandlePolymorphicCallNamed(Call* expr,
                                   HValue* receiver,
                                   ZoneMapList* types,
                                   Handle<String> name);
+  void HandleLiteralCompareTypeof(CompareOperation* compare_expr,
+                                  Expression* expr,
+                                  Handle<String> check);
+  void HandleLiteralCompareUndefined(CompareOperation* compare_expr,
+                                     Expression* expr);                                  
 
   HCompareSymbolEq* BuildSymbolCompare(HValue* left,
                                        HValue* right,
                                        Token::Value op);
   HStringCharCodeAt* BuildStringCharCodeAt(HValue* string,
                                            HValue* index);
   HInstruction* BuildBinaryOperation(BinaryOperation* expr,
                                      HValue* left,
                                      HValue* right);
   HInstruction* BuildIncrement(bool returns_original_input,
@@ skipping 306 matching lines @@
   const char* filename_;
   HeapStringAllocator string_allocator_;
   StringStream trace_;
   int indent_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_H_