Fix representation of HLoadRoot.

src/hydrogen-instructions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HYDROGEN_INSTRUCTIONS_H_
 #define V8_HYDROGEN_INSTRUCTIONS_H_
 
 #include <iosfwd>
 
 #include "src/v8.h"
@@ skipping 2698 matching lines @@
     return index_ == b->index_;
   }
 
  private:
   explicit HLoadRoot(Heap::RootListIndex index, HType type = HType::Tagged())
       : HTemplateInstruction<0>(type), index_(index) {
     SetFlag(kUseGVN);
     // TODO(bmeurer): We'll need kDependsOnRoots once we add the
     // corresponding HStoreRoot instruction.
     SetDependsOnFlag(kCalls);
+    set_representation(Representation::Tagged());
   }
 
   virtual bool IsDeletable() const OVERRIDE { return true; }
 
   const Heap::RootListIndex index_;
 };
 
 
 class HCheckMaps FINAL : public HTemplateInstruction<2> {
  public:
@@ skipping 3637 matching lines @@
       return access_.representation();
   }
 
   const UniqueSet<Map>* maps() const { return maps_; }
 
   virtual bool HasEscapingOperandAt(int index) OVERRIDE { return false; }
   virtual bool HasOutOfBoundsAccess(int size) OVERRIDE {
     return !access().IsInobject() || access().offset() >= size;
   }
   virtual Representation RequiredInputRepresentation(int index) OVERRIDE {
-    if (index == 0 && access().IsExternalMemory()) {
+    if (index == 0) {
       // object must be external in case of external memory access
-      return Representation::External();
+      return access().IsExternalMemory() ? Representation::External()
+                                         : Representation::Tagged();
     }
-    return Representation::Tagged();
+    DCHECK(index == 1);
+    return Representation::None();
   }
   virtual Range* InferRange(Zone* zone) OVERRIDE;
   virtual std::ostream& PrintDataTo(std::ostream& os) const OVERRIDE;  // NOLINT
 
   bool CanBeReplacedWith(HValue* other) const {
     if (!CheckFlag(HValue::kCantBeReplaced)) return false;
     if (!type().Equals(other->type())) return false;
     if (!representation().Equals(other->representation())) return false;
     if (!other->IsLoadNamedField()) return true;
     HLoadNamedField* that = HLoadNamedField::cast(other);
@@ skipping 1502 matching lines @@
 };
 
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_