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 23dbbd289c6c5d5a9e07697368e9fba6ab05e22d..71cd70cd89027e86cdec4a3567c3073898582752 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -6532,8 +6532,12 @@ 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()) {
+          return Representation::Integer32();
+        }
         return field_representation();
       } else if (field_representation().IsExternal()) {
         return Representation::External();
@@ -6561,6 +6565,11 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<3> {
   HValue* new_space_dominator() const { return new_space_dominator_; }
   bool has_transition() const { return has_transition_; }
 
+  // Controls whether it is guaranteed that the smi word already contains
+  // correct smi tag (currently applicable only for x64).
+  bool can_omit_smi_tag_store() const { return can_omit_smi_tag_store_; }
+  void set_can_omit_smi_tag_store(bool v) { can_omit_smi_tag_store_ = v; }

[Toon Verwaest, 2013/12/09 15:51:10]

I'd rather distinguish between "initializing stores" and stores to existing
fields.

// Indicates whether this is a store to a field that was previously initialized
to a value of the same representation.
bool store_to_initialized_field();

[Igor Sheludko, 2013/12/10 09:13:08]

Good suggestion! Done.

+
   Handle<Map> transition_map() const {
     if (has_transition()) {
       return Handle<Map>::cast(
@@ -6614,7 +6623,8 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<3> {
       : access_(access),
         new_space_dominator_(NULL),
         write_barrier_mode_(UPDATE_WRITE_BARRIER),
-        has_transition_(false) {
+        has_transition_(false),
+        can_omit_smi_tag_store_(false) {
     SetOperandAt(0, obj);
     SetOperandAt(1, val);
     SetOperandAt(2, obj);
@@ -6625,6 +6635,7 @@ class HStoreNamedField V8_FINAL : public HTemplateInstruction<3> {
   HValue* new_space_dominator_;
   WriteBarrierMode write_barrier_mode_ : 1;
   bool has_transition_ : 1;
+  bool can_omit_smi_tag_store_ : 1;
 };