New class for Date objects: caches individual date components.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 1236e3870b20e84d2877ffa7a5b0cb9b51192749..1a8022b004b17c40938f29717a1d8198d9f3457e 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -1589,6 +1589,21 @@ LInstruction* LChunkBuilder::DoValueOf(HValueOf* instr) {
 }
 
 
+LInstruction* LChunkBuilder::DoDateField(HDateField* instr) {
+  LOperand* date = UseRegister(instr->value());
+  LDateField* result = new LDateField(date, instr->index());
+  return DefineSameAsFirst(result);
+}
+
+
+LInstruction* LChunkBuilder::DoSetDateField(HSetDateField* instr) {
+  LOperand* date = UseRegister(instr->OperandAt(1));
+  LOperand* value = UseRegister(instr->OperandAt(2));
+  LSetDateField* result = new LSetDateField(date, value, instr->index());
+  return DefineAsRegister(result);
+}
+
+
 LInstruction* LChunkBuilder::DoBoundsCheck(HBoundsCheck* instr) {
   return AssignEnvironment(new LBoundsCheck(
       UseRegisterOrConstantAtStart(instr->index()),