[llvm-commits] CVS: llvm/lib/VMCore/Constants.cpp

[Reid Spencer]

Chris,

Can't we just change this part of ConstantInt:

 /// getTrue/getFalse - Return the singleton true/false values.
  static inline ConstantInt *getTrue() {
    if (TheTrueVal) return TheTrueVal;
    return CreateTrueFalseVals(true);
  }
  static inline ConstantInt *getFalse() {
    if (TheFalseVal) return TheFalseVal;
    return CreateTrueFalseVals(false);
  }

into:
 /// getTrue/getFalse - Return the singleton true/false values.
  static inline ConstantInt *getTrue() {
    return get(Type::Int1Ty, 1);
  }
  static inline ConstantInt *getFalse() {
    return get(Type::Int1Ty, 0);
  }

and get rid of all the special handling of true/false values? Or have we
provided this simply as an optimization on frequently obtained integer
values?

Reid.

On Tue, 2007-02-27 at 11:34 -0800, Reid Spencer wrote:
> On Tue, 2007-02-27 at 09:10 -0800, Chris Lattner wrote:
> > > Index: llvm/lib/VMCore/Constants.cpp
> > > diff -u llvm/lib/VMCore/Constants.cpp:1.222 llvm/lib/VMCore/ 
> > > Constants.cpp:1.223
> > > --- llvm/lib/VMCore/Constants.cpp:1.222	Mon Feb 26 21:05:06 2007
> > > +++ llvm/lib/VMCore/Constants.cpp	Tue Feb 27 01:57:53 2007
> > > @@ -118,7 +118,7 @@
> > >      if (ITy->getBitWidth() == 1)
> > >        return ConstantInt::getTrue();
> > >      else
> > > -      return ConstantInt::get(Ty, int64_t(-1));
> > > +      return ConstantInt::get(Ty, APInt::getAllOnesValue(ITy- 
> > > >getBitWidth()));
> > >    return 0;
> > >  }
> > 
> > The special case for 'i1' can be removed, right?
> 
> I assumed the special case was because of this mess:
> 
> > ConstantInt *ConstantInt::TheTrueVal = 0;
> > ConstantInt *ConstantInt::TheFalseVal = 0;
> > 
> > namespace llvm {
> >   void CleanupTrueFalse(void *) {
> >     ConstantInt::ResetTrueFalse();
> >   }
> > }
> > 
> > static ManagedCleanup<llvm::CleanupTrueFalse> TrueFalseCleanup;
> > 
> > ConstantInt *ConstantInt::CreateTrueFalseVals(bool WhichOne) {
> >   assert(TheTrueVal == 0 && TheFalseVal == 0);
> >   TheTrueVal  = get(Type::Int1Ty, 1);
> >   TheFalseVal = get(Type::Int1Ty, 0);
> > 
> >   // Ensure that llvm_shutdown nulls out TheTrueVal/TheFalseVal.
> >   TrueFalseCleanup.Register();
> > 
> >   return WhichOne ? TheTrueVal : TheFalseVal;
> > }
> 
> why do we need this?
> 
> > 
> > -Chris
> 
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