If the input to an HChange is of type smi, then no need to mark gvn flag changes new space promotio…

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 1739 matching lines @@
 class HChange: public HUnaryOperation {
  public:
   HChange(HValue* value,
           Representation to,
           bool is_truncating,
           bool deoptimize_on_undefined)
       : HUnaryOperation(value) {
     ASSERT(!value->representation().IsNone() && !to.IsNone());
     ASSERT(!value->representation().Equals(to));
     set_representation(to);
-    set_type(HType::TaggedNumber());
     SetFlag(kUseGVN);
     if (deoptimize_on_undefined) SetFlag(kDeoptimizeOnUndefined);
     if (is_truncating) SetFlag(kTruncatingToInt32);
-    if (to.IsTagged()) SetGVNFlag(kChangesNewSpacePromotion);
+    if (value->type().IsSmi()) {
+      set_type(HType::Smi());
+    } else {
+      set_type(HType::TaggedNumber());
+      if (to.IsTagged()) SetGVNFlag(kChangesNewSpacePromotion);
+    }
   }
 
   virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
   virtual HType CalculateInferredType();
   virtual HValue* Canonicalize();
 
   Representation from() const { return value()->representation(); }
   Representation to() const { return representation(); }
   bool deoptimize_on_undefined() const {
     return CheckFlag(kDeoptimizeOnUndefined);
@@ skipping 4716 matching lines @@
   virtual bool IsDeletable() const { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_