Add boolean flag to HChange and LNumberUntagD to not convert undefined to NaN.

src/hydrogen-instructions.h

 // Copyright 2011 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 469 matching lines @@
   enum Flag {
     // Declare global value numbering flags.
   #define DECLARE_DO(type) kChanges##type, kDependsOn##type,
     GVN_FLAG_LIST(DECLARE_DO)
   #undef DECLARE_DO
     kFlexibleRepresentation,
     kUseGVN,
     kCanOverflow,
     kBailoutOnMinusZero,
     kCanBeDivByZero,
+    kDeoptimizeOnUndefined,
     kIsArguments,
     kTruncatingToInt32,
     kLastFlag = kTruncatingToInt32
   };
 
   STATIC_ASSERT(kLastFlag < kBitsPerInt);
 
   static const int kChangesToDependsFlagsLeftShift = 1;
 
   static int ChangesFlagsMask() {
@@ skipping 561 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(ForceRepresentation)
 };
 
 
 class HChange: public HUnaryOperation {
  public:
   HChange(HValue* value,
           Representation from,
           Representation to,
-          bool is_truncating)
-      : HUnaryOperation(value), from_(from) {
+          bool is_truncating,
+          bool deoptimize_on_undefined)
+      : HUnaryOperation(value),
+        from_(from),
+        deoptimize_on_undefined_(deoptimize_on_undefined) {
     ASSERT(!from.IsNone() && !to.IsNone());
     ASSERT(!from.Equals(to));
     set_representation(to);
     SetFlag(kUseGVN);
     if (is_truncating) SetFlag(kTruncatingToInt32);
     if (from.IsInteger32() && to.IsTagged() && value->range() != NULL &&
         value->range()->IsInSmiRange()) {
       set_type(HType::Smi());
     }
   }
 
   virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
 
   Representation from() const { return from_; }
   Representation to() const { return representation(); }
+  bool deoptimize_on_undefined() const { return deoptimize_on_undefined_; }
   virtual Representation RequiredInputRepresentation(int index) const {
     return from_;
   }
 
   virtual void PrintDataTo(StringStream* stream);
 
   DECLARE_CONCRETE_INSTRUCTION(Change)
 
  protected:
   virtual bool DataEquals(HValue* other) {
     if (!other->IsChange()) return false;
     HChange* change = HChange::cast(other);
     return value() == change->value()
-        && to().Equals(change->to());
+        && to().Equals(change->to())
+        && deoptimize_on_undefined() == change->deoptimize_on_undefined();
   }
 
  private:
   Representation from_;
+  bool deoptimize_on_undefined_;
 };
 
 
 class HClampToUint8: public HUnaryOperation {
  public:
   explicit HClampToUint8(HValue* value)
       : HUnaryOperation(value),
         input_rep_(Representation::None()) {
     SetFlag(kFlexibleRepresentation);
     set_representation(Representation::Tagged());
@@ skipping 2913 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(In)
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_