Crankshaft: Recognize (i >>> 0) === i for integer32 inputs and replace

src/hydrogen-instructions.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 3892 matching lines @@
   virtual Representation RequiredInputRepresentation(int index) {
     return representation();
   }
   virtual Representation observed_input_representation(int index) {
     return observed_input_representation_[index];
   }
   virtual void PrintDataTo(StringStream* stream);
 
   virtual void AddInformativeDefinitions();
 
+  virtual HValue* Canonicalize();
+
   DECLARE_CONCRETE_INSTRUCTION(CompareIDAndBranch)
 
  private:
   Representation observed_input_representation_[2];
   Token::Value token_;
 };
 
 
 class HCompareObjectEqAndBranch: public HTemplateControlInstruction<2, 2> {
  public:
@@ skipping 683 matching lines @@
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
                            HValue* right);
 
   virtual bool TryDecompose(DecompositionResult* decomposition) {
     if (right()->IsInteger32Constant()) {
       if (decomposition->Apply(left(), 0, right()->GetInteger32Constant())) {
         // This is intended to look for HAdd and HSub, to handle compounds
-        // like ((base + offset) >> scale) with one single decomposition.
+        // like ((base + offset) >>> scale) with one single decomposition.
         left()->TryDecompose(decomposition);
         return true;
       }
     }
     return false;
   }
 
   virtual Range* InferRange(Zone* zone);
 
   DECLARE_CONCRETE_INSTRUCTION(Shr)
@@ skipping 1864 matching lines @@
   virtual bool IsDeletable() const { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_