Make HValue::ActualValue() traverse all idefs.

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 764 matching lines @@
   HValue* RedefinedOperand() {
     int index = RedefinedOperandIndex();
     return index == kNoRedefinedOperand ? NULL : OperandAt(index);
   }
 
   // A purely informative definition is an idef that will not emit code and
   // should therefore be removed from the graph in the RestoreActualValues
   // phase (so that live ranges will be shorter).
   virtual bool IsPurelyInformativeDefinition() { return false; }
 
-  // This method must always return the original HValue SSA definition
-  // (regardless of any iDef of this value).
+  // This method must always return the original HValue SSA definition,
+  // regardless of any chain of iDefs of this value.
   HValue* ActualValue() {
-    int index = RedefinedOperandIndex();
-    return index == kNoRedefinedOperand ? this : OperandAt(index);
+    HValue* value = this;
+    int index;
+    while ((index = value->RedefinedOperandIndex()) != kNoRedefinedOperand) {
+      value = value->OperandAt(index);
+    }
+    return value;
   }
 
   bool IsInteger32Constant();
   int32_t GetInteger32Constant();
   bool EqualsInteger32Constant(int32_t value);
 
   bool IsDefinedAfter(HBasicBlock* other) const;
 
   // Operands.
   virtual int OperandCount() = 0;
@@ skipping 6169 matching lines @@
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_