Add support to load/store byte fields.

src/hydrogen-instructions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 5874 matching lines @@
     HLoadNamedField* b = HLoadNamedField::cast(other);
     return access_.Equals(b->access_);
   }
 
  private:
   HLoadNamedField(HValue* object, HObjectAccess access) : access_(access) {
     ASSERT(object != NULL);
     SetOperandAt(0, object);
 
     Representation representation = access.representation();
-    if (representation.IsSmi()) {
+    if (representation.IsByte()) {
+      set_representation(Representation::Integer32());
+    } else if (representation.IsSmi()) {
       set_type(HType::Smi());
       set_representation(representation);
     } else if (representation.IsDouble() ||
                representation.IsExternal() ||
                representation.IsInteger32()) {
       set_representation(representation);
     } else if (FLAG_track_heap_object_fields &&
                representation.IsHeapObject()) {
       set_type(HType::NonPrimitive());
       set_representation(Representation::Tagged());
@@ skipping 277 matching lines @@
   virtual bool HasEscapingOperandAt(int index) V8_OVERRIDE {
     return index == 1;
   }
   virtual bool HasOutOfBoundsAccess(int size) V8_OVERRIDE {
     return !access().IsInobject() || access().offset() >= size;
   }
   virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     if (index == 0 && access().IsExternalMemory()) {
       // object must be external in case of external memory access
       return Representation::External();
-    } else if (index == 1 &&
-        (field_representation().IsDouble() ||
-         field_representation().IsSmi() ||
-         field_representation().IsInteger32())) {
-      return field_representation();
+    } else if (index == 1) {
+      if (field_representation().IsByte() ||
+          field_representation().IsInteger32()) {
+        return Representation::Integer32();
+      } else if (field_representation().IsDouble() ||
+                 field_representation().IsSmi()) {
+        return field_representation();
+      }
     }
     return Representation::Tagged();
   }
   virtual void HandleSideEffectDominator(GVNFlag side_effect,
                                          HValue* dominator) V8_OVERRIDE {
     ASSERT(side_effect == kChangesNewSpacePromotion);
     new_space_dominator_ = dominator;
   }
   virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
@@ skipping 856 matching lines @@
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_