HStoreNamedField for Smis optimized for x64

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 4dd24fd871552456a10bb77ab8f6a0e4b4b25138..93b3758df8fdbfe670a943f5fe3e6f044c5e3544 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -6512,10 +6512,20 @@ class HLoadKeyedGeneric V8_FINAL : public HTemplateInstruction<3> {
 };
 
 
+// Indicates whether the store is a store to an entry that was previously
+// initialized or not.
+enum StoreFieldOrKeyedMode {
+  INITIALIZING_STORE,
+  STORE_TO_INITIALIZED_ENTRY
+};
+
+
 class HStoreNamedField V8_FINAL : public HTemplateInstruction<3> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P3(HStoreNamedField, HValue*,
                                  HObjectAccess, HValue*);
+  DECLARE_INSTRUCTION_FACTORY_P4(HStoreNamedField, HValue*,
+                                 HObjectAccess, HValue*, StoreFieldOrKeyedMode);
 
   DECLARE_CONCRETE_INSTRUCTION(StoreNamedField)
 
@@ -6536,8 +6546,12 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<3> {
           field_representation().IsUInteger16() ||
           field_representation().IsInteger32()) {
         return Representation::Integer32();
-      } else if (field_representation().IsDouble() ||
-                 field_representation().IsSmi()) {
+      } else if (field_representation().IsDouble()) {
+        return field_representation();
+      } else if (field_representation().IsSmi()) {
+        if (SmiValuesAre32Bits() && store_mode_ == STORE_TO_INITIALIZED_ENTRY) {
+          return Representation::Integer32();
+        }
         return field_representation();
       } else if (field_representation().IsExternal()) {
         return Representation::External();
@@ -6564,6 +6578,7 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<3> {
   HObjectAccess access() const { return access_; }
   HValue* new_space_dominator() const { return new_space_dominator_; }
   bool has_transition() const { return has_transition_; }
+  StoreFieldOrKeyedMode store_mode() const { return store_mode_; }
 
   Handle<Map> transition_map() const {
     if (has_transition()) {
@@ -6614,11 +6629,13 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<3> {
  private:
   HStoreNamedField(HValue* obj,
                    HObjectAccess access,
-                   HValue* val)
+                   HValue* val,
+                   StoreFieldOrKeyedMode store_mode = INITIALIZING_STORE)
       : access_(access),
         new_space_dominator_(NULL),
         write_barrier_mode_(UPDATE_WRITE_BARRIER),
-        has_transition_(false) {
+        has_transition_(false),
+        store_mode_(store_mode) {
     SetOperandAt(0, obj);
     SetOperandAt(1, val);
     SetOperandAt(2, obj);
@@ -6629,6 +6646,7 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<3> {
   HValue* new_space_dominator_;
   WriteBarrierMode write_barrier_mode_ : 1;
   bool has_transition_ : 1;
+  StoreFieldOrKeyedMode store_mode_ : 1;
 };