Use ICData to collect type feedback on instance setter value. If value is always Smi, insert a smi …

runtime/vm/intermediate_language_x64.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
@@ skipping 1008 matching lines @@
   summary->set_in(1,
       value()->NeedsStoreBuffer() ? Location::WritableRegister()
                                   : Location::RequiresRegister());
   return summary;
 }
 
 
 void StoreInstanceFieldInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Register instance_reg = locs()->in(0).reg();
   Register value_reg = locs()->in(1).reg();
-  if (this->value()->NeedsStoreBuffer()) {
+  if (this->value()->NeedsStoreBuffer() && may_need_store_barrier()) {
     __ StoreIntoObject(instance_reg,
         FieldAddress(instance_reg, field().Offset()), value_reg);
   } else {
     __ StoreIntoObjectNoBarrier(instance_reg,
         FieldAddress(instance_reg, field().Offset()), value_reg);
   }
 }
 
 
 LocationSummary* LoadStaticFieldInstr::MakeLocationSummary() const {
@@ skipping 1291 matching lines @@
     __ j(ABOVE_EQUAL, deopt);
   }
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64