Set kTruncatingToSmi for HChange only when To rep is Smi

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 1245 matching lines @@
   virtual HSourcePosition operand_position(int index) const V8_OVERRIDE {
     const HSourcePosition pos = position_.operand_position(index);
     return pos.IsUnknown() ? position() : pos;
   }
   void set_operand_position(Zone* zone, int index, HSourcePosition pos) {
     ASSERT(0 <= index && index < OperandCount());
     position_.ensure_storage_for_operand_positions(zone, OperandCount());
     position_.set_operand_position(index, pos);
   }
 
+  bool CanTruncateToSmi() const { return CheckFlag(kTruncatingToSmi); }
   bool CanTruncateToInt32() const { return CheckFlag(kTruncatingToInt32); }
 
   virtual LInstruction* CompileToLithium(LChunkBuilder* builder) = 0;
 
 #ifdef DEBUG
   virtual void Verify() V8_OVERRIDE;
 #endif
 
   bool CanDeoptimize();
 
@@ skipping 450 matching lines @@
           Representation to,
           bool is_truncating_to_smi,
           bool is_truncating_to_int32)
       : HUnaryOperation(value) {
     ASSERT(!value->representation().IsNone());
     ASSERT(!to.IsNone());
     ASSERT(!value->representation().Equals(to));
     set_representation(to);
     SetFlag(kUseGVN);
     SetFlag(kCanOverflow);
-    if (is_truncating_to_smi) {
+    if (is_truncating_to_smi && to.IsSmi()) {
       SetFlag(kTruncatingToSmi);
       SetFlag(kTruncatingToInt32);
     }
     if (is_truncating_to_int32) SetFlag(kTruncatingToInt32);
     if (value->representation().IsSmi() || value->type().IsSmi()) {
       set_type(HType::Smi());
     } else {
       set_type(HType::TaggedNumber());
       if (to.IsTagged()) SetChangesFlag(kNewSpacePromotion);
     }
@@ skipping 5779 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_