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avoid constructing out of range shift amounts. 

llvm-svn: 22230
This commit is contained in:
Chris Lattner 2005-06-17 01:29:28 +00:00
parent a2e8779b0d
commit c53cb9d3ff
1 changed files with 4 additions and 2 deletions
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6
llvm/lib/Transforms/Scalar/InstructionCombining.cpp
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@ -2511,8 +2511,10 @@ Instruction *InstCombiner::visitSetCondInst(SetCondInst &I) {
if (!CanFold) { if (!CanFold) {
// To test for the bad case of the signed shr, see if any // To test for the bad case of the signed shr, see if any
// of the bits shifted in could be tested after the mask. // of the bits shifted in could be tested after the mask.
Constant *OShAmt = ConstantUInt::get(Type::UByteTy, int ShAmtVal = Ty->getPrimitiveSizeInBits()-ShAmt->getValue();
Ty->getPrimitiveSizeInBits()-ShAmt->getValue()); if (ShAmtVal < 0) ShAmtVal = 0; // Out of range shift.
Constant *OShAmt = ConstantUInt::get(Type::UByteTy, ShAmtVal);
Constant *ShVal = Constant *ShVal =
ConstantExpr::getShl(ConstantInt::getAllOnesValue(Ty), OShAmt); ConstantExpr::getShl(ConstantInt::getAllOnesValue(Ty), OShAmt);
if (ConstantExpr::getAnd(ShVal, AndCST)->isNullValue()) if (ConstantExpr::getAnd(ShVal, AndCST)->isNullValue())