HStoreNamedField for Smis optimized for x64

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 176dd9fa77a04f8c401cef6fd8da191bd736cefa..b619cbdf04300b4909c1f4fa8befd7412eaa40a9 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -5263,9 +5263,9 @@ HInstruction* HOptimizedGraphBuilder::BuildStoreNamedField(
     }
   } else {
     // This is a normal store.
-    instr = New<HStoreNamedField>(checked_object->ActualValue(),
-                                  field_access,
-                                  value);
+    instr = New<HStoreNamedField>(
+        checked_object->ActualValue(), field_access, value,
+        transition_to_field ? INITIALIZING_STORE : STORE_TO_INITIALIZED_ENTRY);
   }
 
   if (transition_to_field) {
@@ -9476,7 +9476,7 @@ void HOptimizedGraphBuilder::BuildEmitInObjectProperties(
       Add<HStoreNamedField>(object, access, result);
     } else {
       Representation representation = details.representation();
-      HInstruction* value_instruction = Add<HConstant>(value);
+      HInstruction* value_instruction;
 
       if (representation.IsDouble()) {
         // Allocate a HeapNumber box and store the value into it.
@@ -9491,8 +9491,12 @@ void HOptimizedGraphBuilder::BuildEmitInObjectProperties(
         AddStoreMapConstant(double_box,
             isolate()->factory()->heap_number_map());
         Add<HStoreNamedField>(double_box, HObjectAccess::ForHeapNumberValue(),
-            value_instruction);
+                              Add<HConstant>(value));
         value_instruction = double_box;
+      } else if (representation.IsSmi() && value->IsUninitialized()) {
+        value_instruction = graph()->GetConstant0();
+      } else {
+        value_instruction = Add<HConstant>(value);
       }
 
       Add<HStoreNamedField>(object, access, value_instruction);