avoid constructing out of range shift amounts.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22230 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2005-06-17 01:29:28 +00:00
parent 41aaf7016e
commit d7e31cfaae

View File

@ -2511,8 +2511,10 @@ Instruction *InstCombiner::visitSetCondInst(SetCondInst &I) {
if (!CanFold) {
// To test for the bad case of the signed shr, see if any
// of the bits shifted in could be tested after the mask.
Constant *OShAmt = ConstantUInt::get(Type::UByteTy,
Ty->getPrimitiveSizeInBits()-ShAmt->getValue());
int ShAmtVal = Ty->getPrimitiveSizeInBits()-ShAmt->getValue();
if (ShAmtVal < 0) ShAmtVal = 0; // Out of range shift.
Constant *OShAmt = ConstantUInt::get(Type::UByteTy, ShAmtVal);
Constant *ShVal =
ConstantExpr::getShl(ConstantInt::getAllOnesValue(Ty), OShAmt);
if (ConstantExpr::getAnd(ShVal, AndCST)->isNullValue())