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Don't use a potentially expensive shift if all we want is one set bit. 

No functionality change.

llvm-svn: 186095
This commit is contained in:
Benjamin Kramer 2013-07-11 16:05:50 +00:00
parent ce2c84e670
commit fc3ea6f4bc
4 changed files with 6 additions and 6 deletions
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6
llvm/lib/Analysis/ScalarEvolution.cpp
View File

@ -758,7 +758,7 @@ static const SCEV *BinomialCoefficient(const SCEV *It, unsigned K,
unsigned CalculationBits = W + T;
// Calculate 2^T, at width T+W.
APInt DivFactor = APInt(CalculationBits, 1).shl(T);
APInt DivFactor = APInt::getOneBitSet(CalculationBits, T);
// Calculate the multiplicative inverse of K! / 2^T;
// this multiplication factor will perform the exact division by
@ -3789,7 +3789,7 @@ const SCEV *ScalarEvolution::createSCEV(Value *V) {
break;
Constant *X = ConstantInt::get(getContext(),
APInt(BitWidth, 1).shl(SA->getZExtValue()));
APInt::getOneBitSet(BitWidth, SA->getZExtValue()));
return getMulExpr(getSCEV(U->getOperand(0)), getSCEV(X));
}
break;
@ -3807,7 +3807,7 @@ const SCEV *ScalarEvolution::createSCEV(Value *V) {
break;
Constant *X = ConstantInt::get(getContext(),
APInt(BitWidth, 1).shl(SA->getZExtValue()));
APInt::getOneBitSet(BitWidth, SA->getZExtValue()));
return getUDivExpr(getSCEV(U->getOperand(0)), getSCEV(X));
}
break;

2
llvm/lib/Support/ConstantRange.cpp
View File

@ -433,7 +433,7 @@ ConstantRange ConstantRange::zeroExtend(uint32_t DstTySize) const {
APInt LowerExt(DstTySize, 0);
if (!Upper) // special case: [X, 0) -- not really wrapping around
LowerExt = Lower.zext(DstTySize);
return ConstantRange(LowerExt, APInt(DstTySize, 1).shl(SrcTySize));
return ConstantRange(LowerExt, APInt::getOneBitSet(DstTySize, SrcTySize));
}
return ConstantRange(Lower.zext(DstTySize), Upper.zext(DstTySize));

2
llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
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@ -876,7 +876,7 @@ static inline Value *dyn_castFoldableMul(Value *V, ConstantInt *&CST) {
uint32_t BitWidth = cast<IntegerType>(V->getType())->getBitWidth();
uint32_t CSTVal = CST->getLimitedValue(BitWidth);
CST = ConstantInt::get(V->getType()->getContext(),
APInt(BitWidth, 1).shl(CSTVal));
APInt::getOneBitSet(BitWidth, CSTVal));
return I->getOperand(0);
}
return 0;

2
llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
View File

@ -119,7 +119,7 @@ Value *SimplifyIndvar::foldIVUser(Instruction *UseInst, Instruction *IVOperand)
return 0;
D = ConstantInt::get(UseInst->getContext(),
APInt(BitWidth, 1).shl(D->getZExtValue()));
APInt::getOneBitSet(BitWidth, D->getZExtValue()));
}
FoldedExpr = SE->getUDivExpr(SE->getSCEV(IVSrc), SE->getSCEV(D));
}