Improve code for integral modulus calculation.

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 1021 matching lines @@
   }
 
   GVNFlagSet ObservableChangesFlags() const {
     GVNFlagSet result = gvn_flags_;
     result.Intersect(AllChangesFlagSet());
     result.Intersect(AllObservableSideEffectsFlagSet());
     return result;
   }
 
   Range* range() const { return range_; }
+  // We should really use the null object pattern here...

[Jakob Kummerow, 2013/06/07 16:50:07]

nit: I don't think this comment adds value.

[Sven Panne, 2013/06/10 11:05:39]

I'll change this into a real TODO then, code like this is fundamentally
embarrassing and I really like to to this in cleaner way, but not in this CL.

   bool HasRange() const { return range_ != NULL; }
+  bool CanBeNegative() const { return !HasRange() || range()->CanBeNegative(); }
+  bool CanBeZero() const { return !HasRange() || range()->CanBeZero(); }
+  bool RangeCanInclude(int value) const {
+    return !HasRange() || range()->Includes(value);
+  }
   void AddNewRange(Range* r, Zone* zone);
   void RemoveLastAddedRange();
   void ComputeInitialRange(Zone* zone);
 
   // Representation helpers.
   virtual Representation observed_input_representation(int index) {
     return Representation::None();
   }
   virtual Representation RequiredInputRepresentation(int index) = 0;
   virtual void InferRepresentation(HInferRepresentation* h_infer);
@@ skipping 5509 matching lines @@
   virtual bool IsDeletable() const { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_