[llvm-commits] [llvm] r45250 - /llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp

[Evan Cheng]

Hi Chris,

Are you forgetting PatternMatch.h? m_Zero isn't defined anywhere.

Evan

On Dec 19, 2007, at 5:56 PM, Chris Lattner wrote:

> Author: lattner
> Date: Wed Dec 19 19:56:58 2007
> New Revision: 45250
>
> URL: http://llvm.org/viewvc/llvm-project?rev=45250&view=rev
> Log:
> simplify this code with the new m_Zero() pattern.  Make sure the  
> select only
> has a single use, and generalize it to not require N to be a constant.
>
>
> Modified:
>     llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
>
> Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/ 
> Scalar/InstructionCombining.cpp?rev=45250&r1=45249&r2=45250&view=diff
>
> ====================================================================== 
> ========
> --- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp  
> (original)
> +++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Wed  
> Dec 19 19:56:58 2007
> @@ -2109,8 +2109,7 @@
>    }
>
>    // add (cast *A to intptrtype) B ->
> -  //   cast (GEP (cast *A to sbyte*) B) ->
> -  //     intptrtype
> +  //   cast (GEP (cast *A to sbyte*) B)  -->  intptrtype
>    {
>      CastInst *CI = dyn_cast<CastInst>(LHS);
>      Value *Other = RHS;
> @@ -2131,8 +2130,7 @@
>      }
>    }
>
> -  // add (select X 0 (sub n A)) A ->
> -  //  select X A n
> +  // add (select X 0 (sub n A)) A  -->  select X A n
>    {
>      SelectInst *SI = dyn_cast<SelectInst>(LHS);
>      Value *Other = RHS;
> @@ -2140,25 +2138,19 @@
>        SI = dyn_cast<SelectInst>(RHS);
>        Other = LHS;
>      }
> -    if (SI) {
> +    if (SI && SI->hasOneUse()) {
>        Value *TV = SI->getTrueValue();
>        Value *FV = SI->getFalseValue();
> -      Value *A;
> +      Value *A, *N;
>
>        // Can we fold the add into the argument of the select?
>        // We check both true and false select arguments for a  
> matching subtract.
> -      ConstantInt *C1, *C2;
> -      if (match(FV, m_ConstantInt(C1)) && C1->getValue() == 0 &&
> -          match(TV, m_Sub(m_ConstantInt(C2), m_Value(A))) &&
> -          A == Other) {
> -        // We managed to fold the add into the true select value.
> -        return new SelectInst(SI->getCondition(), C2, A);
> -      } else if (match(TV, m_ConstantInt(C1)) && C1->getValue() ==  
> 0 &&
> -                 match(FV, m_Sub(m_ConstantInt(C2), m_Value(A))) &&
> -                 A == Other) {
> -        // We managed to fold the add into the false select value.
> -        return new SelectInst(SI->getCondition(), A, C2);
> -      }
> +      if (match(FV, m_Zero()) && match(TV, m_Sub(m_Value(N),  
> m_Value(A))) &&
> +          A == Other)  // Fold the add into the true select value.
> +        return new SelectInst(SI->getCondition(), N, A);
> +      if (match(TV, m_Zero()) && match(FV, m_Sub(m_Value(N),  
> m_Value(A))) &&
> +          A == Other)  // Fold the add into the false select value.
> +        return new SelectInst(SI->getCondition(), A, N);
>      }
>    }
>
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits