[llvm-commits] [llvm] r108429 - in /llvm/trunk/lib/Transforms/InstCombine: InstCombineAndOrXor.cpp InstCombineSelect.cpp

[Chris Lattner]

On Jul 15, 2010, at 10:24 AM, Owen Anderson wrote:

> Author: resistor
> Date: Thu Jul 15 12:24:23 2010
> New Revision: 108429
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=108429&view=rev
> Log:
> Per Chris' suggestion, get rid of the select canonicalization and just add
> the corresponding or-icmp-and pattern.  This has the added benefit of doing
> the matching earlier, and thus being less susceptible to being confused by
> earlier transforms.

Thanks, btw, the pattern would be cleaner to match with some match(x, m_And(... 's

-Chris

> 
> Modified:
>    llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
>    llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
> 
> Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp?rev=108429&r1=108428&r2=108429&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp (original)
> +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp Thu Jul 15 12:24:23 2010
> @@ -1177,6 +1177,25 @@
>     return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
>   }
> 
> +  // (icmp eq (A & C1), 0) | (icmp eq (A & C2), 0) -->
> +  // (icmp ne (A & (C1|C2)), (C1|C2))
> +  if (LHSCC == ICmpInst::ICMP_EQ && LHSCst->isZero()) {
> +    Instruction *I1 = dyn_cast<Instruction>(Val);
> +    Instruction *I2 = dyn_cast<Instruction>(Val2);
> +    if (I1 && I1->getOpcode() == Instruction::And &&
> +        I2 && I2->getOpcode() == Instruction::And &&
> +        I1->getOperand(0) == I1->getOperand(0)) {
> +      ConstantInt *CI1 = dyn_cast<ConstantInt>(I1->getOperand(1));
> +      ConstantInt *CI2 = dyn_cast<ConstantInt>(I2->getOperand(1));
> +      if (CI1 && !CI1->isZero() && CI2 && !CI2->isZero() &&
> +          CI1->getValue().operator&(CI2->getValue()) == 0) {
> +        Constant *ConstOr = ConstantExpr::getOr(CI1, CI2);
> +        Value *NewAnd = Builder->CreateAnd(I1->getOperand(0), ConstOr);
> +        return Builder->CreateICmp(ICmpInst::ICMP_NE, NewAnd, ConstOr);
> +      }
> +    }
> +  }
> +  
>   // From here on, we only handle:
>   //    (icmp1 A, C1) | (icmp2 A, C2) --> something simpler.
>   if (Val != Val2) return 0;
> 
> Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp?rev=108429&r1=108428&r2=108429&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp (original)
> +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp Thu Jul 15 12:24:23 2010
> @@ -699,34 +699,6 @@
>     SI.setOperand(2, TrueVal);
>     return &SI;
>   }
> -  
> -  // select (A == 0 | B == 0), T, F--> select (A != 0 & B != 0), F, T
> -  // Note: This is a canonicalization rather than an optimization, and is used
> -  // to expose opportunities to other instcombine transforms.
> -  Instruction* CondInst = dyn_cast<Instruction>(CondVal);
> -  if (CondInst && CondInst->hasOneUse() && 
> -      CondInst->getOpcode() == Instruction::Or) {
> -    ICmpInst *LHSCmp = dyn_cast<ICmpInst>(CondInst->getOperand(0));
> -    ICmpInst *RHSCmp = dyn_cast<ICmpInst>(CondInst->getOperand(1));
> -    if (LHSCmp && LHSCmp->hasOneUse() &&
> -                  LHSCmp->getPredicate() == ICmpInst::ICMP_EQ &&
> -        RHSCmp && RHSCmp->hasOneUse() &&
> -                  RHSCmp->getPredicate() == ICmpInst::ICMP_EQ) {
> -      ConstantInt* C1 = dyn_cast<ConstantInt>(LHSCmp->getOperand(1));
> -      ConstantInt* C2 = dyn_cast<ConstantInt>(RHSCmp->getOperand(1));
> -      if (C1 && C1->isZero() && C2 && C2->isZero()) {
> -        LHSCmp->setPredicate(ICmpInst::ICMP_NE);
> -        RHSCmp->setPredicate(ICmpInst::ICMP_NE);
> -        Value *And =
> -          InsertNewInstBefore(BinaryOperator::CreateAnd(LHSCmp, RHSCmp,
> -                                             "and."+CondVal->getName()), SI);
> -        SI.setOperand(0, And);
> -        SI.setOperand(1, FalseVal);
> -        SI.setOperand(2, TrueVal);
> -        return &SI;
> -      }
> -    }
> -  }
> 
>   return 0;
> }
> 
> 
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