Make sure to use signed arithmetic in APInt to fix a regression.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71090 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
David Greene 2009-05-06 17:39:26 +00:00
parent e9d87f4906
commit e19c840d6c

View File

@ -2027,9 +2027,10 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond,
Scale = SSInt / CmpSSInt;
int64_t NewCmpVal = CmpVal * Scale;
APInt Mul = APInt(BitWidth, NewCmpVal);
APInt Mul = APInt(BitWidth*2, CmpVal, true);
Mul = Mul * APInt(BitWidth*2, Scale, true);
// Check for overflow.
if (Mul.getSExtValue() != NewCmpVal)
if (!Mul.isSignedIntN(BitWidth)) {
continue;
// Watch out for overflow.