Fix GetMinTrailingZeros for SCEVSignExtend and SCEVZeroExtendExpr to

return the correct value when the cast operand is all zeros. This ought
to be pretty rare, because it would mean that the regular SCEV folding
routines missed a case, though there are cases they might legitimately
miss. Also, it's unlikely anything currently using GetMinTrailingZeros
cares about this case.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71532 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-05-12 01:23:18 +00:00
parent 6ed34918eb
commit 42a5875e10

View File

@ -1984,13 +1984,13 @@ static uint32_t GetMinTrailingZeros(SCEVHandle S, const ScalarEvolution &SE) {
if (const SCEVZeroExtendExpr *E = dyn_cast<SCEVZeroExtendExpr>(S)) {
uint32_t OpRes = GetMinTrailingZeros(E->getOperand(), SE);
return OpRes == SE.getTypeSizeInBits(E->getOperand()->getType()) ?
SE.getTypeSizeInBits(E->getOperand()->getType()) : OpRes;
SE.getTypeSizeInBits(E->getType()) : OpRes;
}
if (const SCEVSignExtendExpr *E = dyn_cast<SCEVSignExtendExpr>(S)) {
uint32_t OpRes = GetMinTrailingZeros(E->getOperand(), SE);
return OpRes == SE.getTypeSizeInBits(E->getOperand()->getType()) ?
SE.getTypeSizeInBits(E->getOperand()->getType()) : OpRes;
SE.getTypeSizeInBits(E->getType()) : OpRes;
}
if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(S)) {