Re-use phi reachability information to avoid a fixed-point computation.

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 2191 matching lines @@
   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;
   }
 
+  bool AllOperandsConvertibleToInteger() {
+    for (int i = 0; i < OperandCount(); ++i) {
+      if (!OperandAt(i)->IsConvertibleToInteger()) return false;
+    }
+    return true;
+  }
+
  protected:
   virtual void DeleteFromGraph();
   virtual void InternalSetOperandAt(int index, HValue* value) {
     inputs_[index] = value;
   }
 
  private:
   ZoneList<HValue*> inputs_;
   int merged_index_;
 
@@ skipping 1970 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(In)
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_