New class for Date objects: caches individual date components.

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index 04e9d246a93ed15dde8d2f325359a28eec8be02c..ac8d7c0e50cb81e8be17303906a04bc4ba9427e4 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -1648,6 +1648,14 @@ LInstruction* LChunkBuilder::DoValueOf(HValueOf* instr) {
 }
 
 
+LInstruction* LChunkBuilder::DoDateField(HDateField* instr) {
+  LOperand* object = UseRegister(instr->value());
+  LDateField* result =
+      new(zone()) LDateField(object, TempRegister(), instr->index());
+  return DefineSameAsFirst(result);
+}
+
+
 LInstruction* LChunkBuilder::DoBoundsCheck(HBoundsCheck* instr) {
   return AssignEnvironment(new(zone()) LBoundsCheck(
       UseRegisterOrConstantAtStart(instr->index()),