Fix bug with GVN on array loads.

src/hydrogen-instructions.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 577 matching lines @@
   }
 
   bool IsDefinedAfter(HBasicBlock* other) const;
 
   // Operands.
   virtual int OperandCount() = 0;
   virtual HValue* OperandAt(int index) = 0;
   void SetOperandAt(int index, HValue* value);
 
   void DeleteAndReplaceWith(HValue* other);
+  void ReplaceAllUsesWith(HValue* other);
   bool HasNoUses() const { return use_list_ == NULL; }
   bool HasMultipleUses() const {
     return use_list_ != NULL && use_list_->tail() != NULL;
   }
   int UseCount() const;
   void ClearOperands();
 
   int flags() const { return flags_; }
   void SetFlag(Flag f) { flags_ |= (1 << f); }
   void ClearFlag(Flag f) { flags_ &= ~(1 << f); }
@@ skipping 69 matching lines @@
  private:
   // A flag mask to mark an instruction as having arbitrary side effects.
   static int AllSideEffects() {
     return ChangesFlagsMask() & ~(1 << kChangesOsrEntries);
   }
 
   // Remove the matching use from the use list if present.  Returns the
   // removed list node or NULL.
   HUseListNode* RemoveUse(HValue* value, int index);
 
-  void ReplaceAllUsesWith(HValue* other);
-
   void RegisterUse(int index, HValue* new_value);
 
   HBasicBlock* block_;
 
   // The id of this instruction in the hydrogen graph, assigned when first
   // added to the graph. Reflects creation order.
   int id_;
 
   Representation representation_;
   HType type_;
@@ skipping 1697 matching lines @@
   DECLARE_CONCRETE_INSTRUCTION(AccessArgumentsAt)
 
   virtual bool DataEquals(HValue* other) { return true; }
 };
 
 
 class HBoundsCheck: public HBinaryOperation {
  public:
   HBoundsCheck(HValue* index, HValue* length)
       : HBinaryOperation(index, length) {
+    set_representation(Representation::Integer32());
     SetFlag(kUseGVN);
   }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Integer32();
   }
 
 #ifdef DEBUG
   virtual void Verify();
 #endif
@@ skipping 1613 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(In)
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_