Add rotate-right instruction to hydrogen and use it instead of bitwise operations

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 135 matching lines @@
   V(Mul)                                       \
   V(ObjectLiteral)                             \
   V(OsrEntry)                                  \
   V(OuterContext)                              \
   V(Parameter)                                 \
   V(Power)                                     \
   V(PushArgument)                              \
   V(Random)                                    \
   V(RegExpLiteral)                             \
   V(Return)                                    \
+  V(Ror)                                       \
   V(Sar)                                       \
   V(Shl)                                       \
   V(Shr)                                       \
   V(Simulate)                                  \
   V(SoftDeoptimize)                            \
   V(StackCheck)                                \
   V(StoreContextSlot)                          \
   V(StoreGlobalCell)                           \
   V(StoreGlobalGeneric)                        \
   V(StoreKeyedFastDoubleElement)               \
@@ skipping 724 matching lines @@
   bool CanTruncateToInt32() const { return CheckFlag(kTruncatingToInt32); }
 
   virtual LInstruction* CompileToLithium(LChunkBuilder* builder) = 0;
 
 #ifdef DEBUG
   virtual void Verify();
 #endif
 
   virtual bool IsCall() { return false; }
 
+  bool UnusedAndSafeToDelete() const {
+    bool deleteable_operation = IsBitwiseBinaryOperation();

[ulan, 2012/10/01 18:15:19]

danno, michael: any suggestions for other instruction types to add here?

+    return HasNoUses() && !HasObservableSideEffects() && deleteable_operation;
+  }
+
   DECLARE_ABSTRACT_INSTRUCTION(Instruction)
 
  protected:
   HInstruction()
       : next_(NULL),
         previous_(NULL),
         position_(RelocInfo::kNoPosition) {
     SetGVNFlag(kDependsOnOsrEntries);
   }
 
@@ skipping 2732 matching lines @@
                                HValue* left,
                                HValue* right);
 
   DECLARE_CONCRETE_INSTRUCTION(Sar)
 
  protected:
   virtual bool DataEquals(HValue* other) { return true; }
 };
 
 
+class HRor: public HBitwiseBinaryOperation {
+ public:
+  HRor(HValue* context, HValue* left, HValue* right)
+      : HBitwiseBinaryOperation(context, left, right) {
+    ChangeRepresentation(Representation::Integer32());
+  }
+
+  virtual Representation RequiredInputRepresentation(int index) {
+    return Representation::Integer32();
+  }
+
+  static HInstruction* NewHRor(Zone* zone,
+                               HValue* context,
+                               HValue* left,
+                               HValue* right);
+
+  DECLARE_CONCRETE_INSTRUCTION(Ror)
+
+ protected:
+  virtual bool DataEquals(HValue* other) { return true; }
+};
+
+
 class HOsrEntry: public HTemplateInstruction<0> {
  public:
   explicit HOsrEntry(BailoutId ast_id) : ast_id_(ast_id) {
     SetGVNFlag(kChangesOsrEntries);
   }
 
   BailoutId ast_id() const { return ast_id_; }
 
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::None();
@@ skipping 1620 matching lines @@
   DECLARE_CONCRETE_INSTRUCTION(LoadFieldByIndex);
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_