Assign less environments in StoreNamedField

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index 5463a9a87f8fda421cce745b36b6d5d2aa14a75f..548da2e40904f936f6b1940d390a2fd188e70287 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -2354,10 +2354,11 @@ LInstruction* LChunkBuilder::DoStoreNamedField(HStoreNamedField* instr) {
   LOperand* temp = needs_write_barrier_for_map ? TempRegister() : NULL;
 
   LStoreNamedField* result = new(zone()) LStoreNamedField(obj, val, temp);
-  if ((FLAG_track_fields && instr->field_representation().IsSmi()) ||
-      (FLAG_track_heap_object_fields &&
-       instr->field_representation().IsHeapObject())) {
-    return AssignEnvironment(result);
+  if (FLAG_track_heap_object_fields &&
+      instr->field_representation().IsHeapObject()) {
+    if (!instr->value()->type().IsHeapObject()) {
+      return AssignEnvironment(result);
+    }
   }
   return result;
 }