Change heuristics for deciding phi-representation types to use int32 more frequently.

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 536 matching lines @@
   Representation representation() const { return representation_; }
   void ChangeRepresentation(Representation r) {
     // Representation was already set and is allowed to be changed.
     ASSERT(!representation_.IsNone());
     ASSERT(!r.IsNone());
     ASSERT(CheckFlag(kFlexibleRepresentation));
     RepresentationChanged(r);
     representation_ = r;
   }
 
+  virtual bool IsConvertibleToInteger() const { return true; }
+
   HType type() const { return type_; }
   void set_type(HType type) {
     ASSERT(HasNoUses());
     type_ = type;
   }
 
   // An operation needs to override this function iff:
   //   1) it can produce an int32 output.
   //   2) the true value of its output can potentially be minus zero.
   // The implementation must set a flag so that it bails out in the case where
@@ skipping 1348 matching lines @@
   virtual bool DataEquals(HValue* other) { return true; }
 };
 
 
 class HPhi: public HValue {
  public:
   explicit HPhi(int merged_index)
       : inputs_(2),
         merged_index_(merged_index),
         phi_id_(-1),
-        is_live_(false) {
+        is_live_(false),
+        is_convertible_to_integer_(true) {
     for (int i = 0; i < Representation::kNumRepresentations; i++) {
       non_phi_uses_[i] = 0;
       indirect_uses_[i] = 0;
     }
     ASSERT(merged_index >= 0);
     set_representation(Representation::Tagged());
     SetFlag(kFlexibleRepresentation);
   }
 
   virtual Representation InferredRepresentation() {
@@ skipping 57 matching lines @@
   int phi_id() { return phi_id_; }
   bool is_live() { return is_live_; }
   void set_is_live(bool b) { is_live_ = b; }
 
   static HPhi* cast(HValue* value) {
     ASSERT(value->IsPhi());
     return reinterpret_cast<HPhi*>(value);
   }
   virtual Opcode opcode() const { return HValue::kPhi; }
 
+  virtual bool IsConvertibleToInteger() const {
+    return is_convertible_to_integer_;
+  }
+
+  void set_is_convertible_to_integer(bool b) {
+    is_convertible_to_integer_ = b;
+  }
+
  protected:
   virtual void DeleteFromGraph();
   virtual void InternalSetOperandAt(int index, HValue* value) {
     inputs_[index] = value;
   }
 
  private:
   ZoneList<HValue*> inputs_;
   int merged_index_;
 
   int non_phi_uses_[Representation::kNumRepresentations];
   int indirect_uses_[Representation::kNumRepresentations];
   int phi_id_;
   bool is_live_;
+  bool is_convertible_to_integer_;
 };
 
 
 class HArgumentsObject: public HTemplateInstruction<0> {
  public:
   HArgumentsObject() {
     set_representation(Representation::Tagged());
     SetFlag(kIsArguments);
   }
 
@@ skipping 10 matching lines @@
   HConstant(Handle<Object> handle, Representation r);
 
   Handle<Object> handle() const { return handle_; }
 
   bool InOldSpace() const { return !HEAP->InNewSpace(*handle_); }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::None();
   }
 
+  virtual bool IsConvertibleToInteger() const {
+    if (handle_->IsSmi()) return true;
+    if (handle_->IsHeapNumber() &&
+        (HeapNumber::cast(*handle_)->value() ==
+         static_cast<double>(NumberToInt32(*handle_)))) return true;
+    return false;
+  }
+
   virtual bool EmitAtUses() { return !representation().IsDouble(); }
   virtual void PrintDataTo(StringStream* stream);
   virtual HType CalculateInferredType();
   bool IsInteger() const { return handle_->IsSmi(); }
   HConstant* CopyToRepresentation(Representation r) const;
   HConstant* CopyToTruncatedInt32() const;
   bool HasInteger32Value() const { return has_int32_value_; }
   int32_t Integer32Value() const {
     ASSERT(HasInteger32Value());
     return int32_value_;
@@ skipping 1749 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(In)
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_