Implement caching scheme for Date fields.

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 57005ff77e08d3577070cccc764fcd2ffbea804c..db8fa2a637e861336a34dd6686cac853e9308b59 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -1656,8 +1656,8 @@ LInstruction* LChunkBuilder::DoDateField(HDateField* instr) {
 
 
 LInstruction* LChunkBuilder::DoSetDateField(HSetDateField* instr) {
-  LOperand* date = UseRegister(instr->OperandAt(1));
-  LOperand* value = UseRegister(instr->OperandAt(2));
+  LOperand* date = UseTempRegister(instr->OperandAt(1));
+  LOperand* value = UseTempRegister(instr->OperandAt(2));
   LSetDateField* result =
       new(zone()) LSetDateField(date, value, TempRegister(), instr->index());
   return DefineAsRegister(result);