Use a register spec for StoreIC and KeyedStoreIC.

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 6d1c3dd3009467e83b78d692cdfb3a6cb28d00ab..c0be3a53b065ddd5e4ffd871fb28da2f9a80158d 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -2272,9 +2272,10 @@ LInstruction* LChunkBuilder::DoStoreKeyed(HStoreKeyed* instr) {
 
 LInstruction* LChunkBuilder::DoStoreKeyedGeneric(HStoreKeyedGeneric* instr) {
   LOperand* context = UseFixed(instr->context(), rsi);
-  LOperand* object = UseFixed(instr->object(), rdx);
-  LOperand* key = UseFixed(instr->key(), rcx);
-  LOperand* value = UseFixed(instr->value(), rax);
+  LOperand* object = UseFixed(instr->object(),
+                              KeyedStoreIC::ReceiverRegister());
+  LOperand* key = UseFixed(instr->key(), KeyedStoreIC::NameRegister());
+  LOperand* value = UseFixed(instr->value(), KeyedStoreIC::ValueRegister());
 
   ASSERT(instr->object()->representation().IsTagged());
   ASSERT(instr->key()->representation().IsTagged());
@@ -2369,8 +2370,8 @@ LInstruction* LChunkBuilder::DoStoreNamedField(HStoreNamedField* instr) {
 
 LInstruction* LChunkBuilder::DoStoreNamedGeneric(HStoreNamedGeneric* instr) {
   LOperand* context = UseFixed(instr->context(), rsi);
-  LOperand* object = UseFixed(instr->object(), rdx);
-  LOperand* value = UseFixed(instr->value(), rax);
+  LOperand* object = UseFixed(instr->object(), StoreIC::ReceiverRegister());
+  LOperand* value = UseFixed(instr->value(), StoreIC::ValueRegister());
 
   LStoreNamedGeneric* result =
       new(zone()) LStoreNamedGeneric(context, object, value);