Enable redundancy elimination for array loads.

runtime/vm/intermediate_language.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 2677 matching lines @@
   intptr_t class_id() const { return class_id_; }
 
   virtual bool CanDeoptimize() const { return false; }
 
   virtual bool HasSideEffect() const { return false; }
 
   virtual intptr_t ResultCid() const;
 
   virtual Representation representation() const;
 
+  virtual bool AttributesEqual(Instruction* other) const;
+
+  virtual bool AffectedBySideEffect() const { return true; }
+
  private:
   const intptr_t class_id_;
 
   DISALLOW_COPY_AND_ASSIGN(LoadIndexedInstr);
 };
 
 
 class StoreIndexedInstr : public TemplateDefinition<3> {
  public:
   StoreIndexedInstr(Value* array,
@@ skipping 1533 matching lines @@
   ForwardInstructionIterator* current_iterator_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_