Get rid of the HInstanceSize instruction.

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 108 matching lines @@
   V(FunctionLiteral)                           \
   V(GetCachedArrayIndex)                       \
   V(GlobalObject)                              \
   V(GlobalReceiver)                            \
   V(Goto)                                      \
   V(HasCachedArrayIndexAndBranch)              \
   V(HasInstanceTypeAndBranch)                  \
   V(InnerAllocatedObject)                      \
   V(InstanceOf)                                \
   V(InstanceOfKnownGlobal)                     \
-  V(InstanceSize)                              \
   V(InvokeFunction)                            \
   V(IsConstructCallAndBranch)                  \
   V(IsObjectAndBranch)                         \
   V(IsStringAndBranch)                         \
   V(IsSmiAndBranch)                            \
   V(IsUndetectableAndBranch)                   \
   V(LeaveInlined)                              \
   V(LoadContextSlot)                           \
   V(LoadExternalArrayPointer)                  \
   V(LoadFieldByIndex)                          \
@@ skipping 4303 matching lines @@
     SetOperandAt(0, context);
     SetOperandAt(1, left);
     set_representation(Representation::Tagged());
     SetAllSideEffects();
   }
 
   Handle<JSFunction> function_;
 };
 
 
-// TODO(mstarzinger): This instruction should be modeled as a load of the map
-// field followed by a load of the instance size field once HLoadNamedField is
-// flexible enough to accommodate byte-field loads.
-class HInstanceSize V8_FINAL : public HTemplateInstruction<1> {
- public:
-  explicit HInstanceSize(HValue* object) {
-    SetOperandAt(0, object);
-    set_representation(Representation::Integer32());
-  }
-
-  HValue* object() { return OperandAt(0); }
-
-  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
-    return Representation::Tagged();
-  }
-
-  DECLARE_CONCRETE_INSTRUCTION(InstanceSize)
-};
-
-
 class HPower V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HInstruction* New(Zone* zone,
                            HValue* context,
                            HValue* left,
                            HValue* right);
 
   HValue* left() { return OperandAt(0); }
   HValue* right() const { return OperandAt(1); }
 
@@ skipping 1315 matching lines @@
   }
 
   static HObjectAccess ForFunctionContextPointer() {
     return HObjectAccess(kInobject, JSFunction::kContextOffset);
   }
 
   static HObjectAccess ForMap() {
     return HObjectAccess(kMaps, JSObject::kMapOffset);
   }
 
+  static HObjectAccess ForMapInstanceSize() {
+    return HObjectAccess(kInobject,
+                         Map::kInstanceSizeOffset,
+                         Representation::Byte());
+  }
+
   static HObjectAccess ForPropertyCellValue() {
     return HObjectAccess(kInobject, PropertyCell::kValueOffset);
   }
 
   static HObjectAccess ForCellValue() {
     return HObjectAccess(kInobject, Cell::kValueOffset);
   }
 
   static HObjectAccess ForAllocationMementoSite() {
     return HObjectAccess(kInobject, AllocationMemento::kAllocationSiteOffset);
@@ skipping 1293 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_