return isLoopInvariant(Src, LoopNest);
const SCEV *Start = AddRec->getStart();
const SCEV *Step = AddRec->getStepRecurrence(*SE);
+ const SCEV *UB = SE->getBackedgeTakenCount(AddRec->getLoop());
+ if (!isa<SCEVCouldNotCompute>(UB)) {
+ if (SE->getTypeSizeInBits(Start->getType()) <
+ SE->getTypeSizeInBits(UB->getType())) {
+ if (!AddRec->getNoWrapFlags())
+ return false;
+ }
+ }
if (!isLoopInvariant(Step, LoopNest))
return false;
Loops.set(mapSrcLoop(AddRec->getLoop()));
return isLoopInvariant(Dst, LoopNest);
const SCEV *Start = AddRec->getStart();
const SCEV *Step = AddRec->getStepRecurrence(*SE);
+ const SCEV *UB = SE->getBackedgeTakenCount(AddRec->getLoop());
+ if (!isa<SCEVCouldNotCompute>(UB)) {
+ if (SE->getTypeSizeInBits(Start->getType()) <
+ SE->getTypeSizeInBits(UB->getType())) {
+ if (!AddRec->getNoWrapFlags())
+ return false;
+ }
+ }
if (!isLoopInvariant(Step, LoopNest))
return false;
Loops.set(mapDstLoop(AddRec->getLoop()));
// All subscripts are all the same type.
// Loop bound may be smaller (e.g., a char).
// Should zero extend loop bound, since it's always >= 0.
-// This routine collects upper bound and extends if needed.
+// This routine collects upper bound and extends or truncates if needed.
+// Truncating is safe when subscripts are known not to wrap. Cases without
+// nowrap flags should have been rejected earlier.
// Return null if no bound available.
const SCEV *DependenceAnalysis::collectUpperBound(const Loop *L,
Type *T) const {
if (SE->hasLoopInvariantBackedgeTakenCount(L)) {
const SCEV *UB = SE->getBackedgeTakenCount(L);
- return SE->getNoopOrZeroExtend(UB, T);
+ return SE->getTruncateOrZeroExtend(UB, T);
}
return nullptr;
}