Add HLoadRoot hydrogen 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 125 matching lines @@
   V(LoadContextSlot)                           \
   V(LoadExternalArrayPointer)                  \
   V(LoadFieldByIndex)                          \
   V(LoadFunctionPrototype)                     \
   V(LoadGlobalCell)                            \
   V(LoadGlobalGeneric)                         \
   V(LoadKeyed)                                 \
   V(LoadKeyedGeneric)                          \
   V(LoadNamedField)                            \
   V(LoadNamedGeneric)                          \
+  V(LoadRoot)                                  \
   V(MapEnumLength)                             \
   V(MathFloorOfDiv)                            \
   V(MathMinMax)                                \
   V(Mod)                                       \
   V(Mul)                                       \
   V(OsrEntry)                                  \
   V(OuterContext)                              \
   V(Parameter)                                 \
   V(Power)                                     \
   V(PushArgument)                              \
@@ skipping 2352 matching lines @@
     SetFlag(kUseGVN);
     SetFlag(kAllowUndefinedAsNaN);
   }
 
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 
   BuiltinFunctionId op_;
 };
 
 
+class HLoadRoot V8_FINAL : public HTemplateInstruction<0> {
+ public:
+  DECLARE_INSTRUCTION_FACTORY_P1(HLoadRoot, Heap::RootListIndex);
+  DECLARE_INSTRUCTION_FACTORY_P2(HLoadRoot, Heap::RootListIndex, HType);
+
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
+    return Representation::None();
+  }
+
+  Heap::RootListIndex index() const { return index_; }
+
+  DECLARE_CONCRETE_INSTRUCTION(LoadRoot)
+
+ protected:
+  virtual bool DataEquals(HValue* other) V8_OVERRIDE {
+    HLoadRoot* b = HLoadRoot::cast(other);
+    return index_ == b->index_;
+  }
+
+ private:
+  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.
+    SetGVNFlag(kDependsOnCalls);
+  }
+
+  virtual bool IsDeletable() const V8_OVERRIDE { return true; }
+
+  const Heap::RootListIndex index_;
+};
+
+
 class HLoadExternalArrayPointer V8_FINAL : public HUnaryOperation {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HLoadExternalArrayPointer, HValue*);
 
   virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
 
   virtual HType CalculateInferredType() V8_OVERRIDE {
     return HType::None();
@@ skipping 4447 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_