New class for Date objects: caches individual date components.

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 161 matching lines @@
   V(ThisFunction)                              \
   V(Throw)                                     \
   V(ToFastProperties)                          \
   V(ToInt32)                                   \
   V(TransitionElementsKind)                    \
   V(Typeof)                                    \
   V(TypeofIsAndBranch)                         \
   V(UnaryMathOperation)                        \
   V(UnknownOSRValue)                           \
   V(UseConst)                                  \
-  V(ValueOf)
+  V(ValueOf)                                   \
+  V(DateField)

[ulan, 2012/01/25 13:08:48]

Don't forget SetDateField.

[rossberg, 2012/01/25 15:48:37]

There was no HSetDateField instruction. ;) However, it exists now.

 
 #define GVN_FLAG_LIST(V)                       \
   V(Calls)                                     \
   V(InobjectFields)                            \
   V(BackingStoreFields)                        \
   V(ElementsKind)                              \
   V(ArrayElements)                             \
   V(DoubleArrayElements)                       \
   V(SpecializedArrayElements)                  \
   V(GlobalVars)                                \
@@ skipping 4310 matching lines @@
   }
 
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::Tagged();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(ValueOf)
 };
 
 
+class HDateField: public HUnaryOperation {

[ulan, 2012/01/25 13:08:48]

This instruction has two arguments, so HBinaryOperation or
HTemplateInstruction<2> seem more appropriate.

[rossberg, 2012/01/25 15:48:37]

No, it's a unary instruction. The index is merely a static attribute.

+ public:
+  HDateField(HValue* value, int index)
+    : HUnaryOperation(value), index_(index) {
+    set_representation(Representation::Tagged());

[ulan, 2012/01/25 13:08:48]

Is it possible to use Int32 representation and deoptimize if NaN?

[rossberg, 2012/01/25 15:48:37]

Then I would need to implement the untagging in the instruction. I don't see
what the win would be. The integers cannot be untagged on the object itself.

+  }
+
+  int index() const { return index_; }
+
+  virtual Representation RequiredInputRepresentation(int index) {
+    return Representation::Tagged();
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(DateField)
+
+ private:
+  int index_;
+};
+
+
 class HDeleteProperty: public HBinaryOperation {
  public:
   HDeleteProperty(HValue* context, HValue* obj, HValue* key)
       : HBinaryOperation(context, obj, key) {
     set_representation(Representation::Tagged());
     SetAllSideEffects();
   }
 
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::Tagged();
@@ skipping 34 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(In)
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_