Pass checked values to HLoadNamedField, removing the need for extra type-check field.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index b4fc65635f47b6db2396208e73b0b3b9e124f996..060066de4809fcbc049aadab68ef1976b4b8aa46 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -1359,6 +1359,9 @@ class HCompareMap: public HUnaryControlInstruction {
 
   DECLARE_CONCRETE_INSTRUCTION(CompareMap)
 
+ protected:
+  virtual int RedefinedOperandIndex() { return 0; }
+
  private:
   Handle<Map> map_;
 };
@@ -2598,6 +2601,8 @@ class HCheckMaps: public HTemplateInstruction<2> {
     return true;
   }
 
+  virtual int RedefinedOperandIndex() { return 0; }
+
  private:
   // Clients should use one of the static New* methods above.
   HCheckMaps(HValue* value, Zone *zone, HValue* typecheck)
@@ -2714,6 +2719,8 @@ class HCheckInstanceType: public HUnaryOperation {
     return check_ == b->check_;
   }
 
+  virtual int RedefinedOperandIndex() { return 0; }
+
  private:
   enum Check {
     IS_SPEC_OBJECT,
@@ -5555,20 +5562,13 @@ class HObjectAccess {
 };
 
 
-class HLoadNamedField: public HTemplateInstruction<2> {
+class HLoadNamedField: public HTemplateInstruction<1> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P2(HLoadNamedField, HValue*, HObjectAccess);
-  DECLARE_INSTRUCTION_FACTORY_P3(HLoadNamedField, HValue*, HObjectAccess,
-                                 HValue*);
 
   HValue* object() { return OperandAt(0); }
-  HValue* typecheck() {
-    ASSERT(HasTypeCheck());
-    return OperandAt(1);
-  }
-
-  bool HasTypeCheck() const { return OperandAt(0) != OperandAt(1); }
-  void ClearTypeCheck() { SetOperandAt(1, object()); }
+  bool HasTypeCheck() { return object()->IsCheckMaps(); }
+  void ClearTypeCheck() { SetOperandAt(0, object()->ActualValue()); }
   HObjectAccess access() const { return access_; }
   Representation field_representation() const {
       return access_.representation();
@@ -5594,13 +5594,9 @@ class HLoadNamedField: public HTemplateInstruction<2> {
   }
 
  private:
-  HLoadNamedField(HValue* object,
-                  HObjectAccess access,
-                  HValue* typecheck = NULL)
-      : access_(access) {
+  HLoadNamedField(HValue* object, HObjectAccess access) : access_(access) {
     ASSERT(object != NULL);
     SetOperandAt(0, object);
-    SetOperandAt(1, typecheck != NULL ? typecheck : object);
 
     Representation representation = access.representation();
     if (representation.IsSmi()) {