Displaying 1 result from an estimated 1 matches for "conservativeresult".
2015 Jan 15
4
[LLVMdev] confusion w.r.t. scalar evolution and nuw
...t;(S)) {
// If there's no unsigned wrap, the value will never be less than its
// initial value.
if (AddRec->getNoWrapFlags(SCEV::FlagNUW))
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(AddRec->getStart()))
if (!C->getValue()->isZero())
ConservativeResult =
ConservativeResult.intersectWith(
ConstantRange(C->getValue()->getValue(), APInt(BitWidth, 0)));
and conclude that %idx.dec is always UGE %begin. This is a real bug
waiting to happen.
As far as I can tell, in the presence of no-wrap flags, 'sub X Y' is
n...