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[LFTR] Strengthen assertions in genLoopLimit [NFCI] 

llvm-svn: 360978
This commit is contained in:
Philip Reames 2019-05-17 02:18:03 +00:00
parent f51dc8d2f9
commit a74d654374
1 changed files with 3 additions and 3 deletions
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6
llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
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@ -2263,8 +2263,8 @@ static PHINode *FindLoopCounter(Loop *L, const SCEV *BECount,
/// is taken IVCount times.
static Value *genLoopLimit(PHINode *IndVar, const SCEV *IVCount, Loop *L,
SCEVExpander &Rewriter, ScalarEvolution *SE) {
const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(SE->getSCEV(IndVar));
assert(AR && AR->getLoop() == L && AR->isAffine() && "bad loop counter");
assert(isLoopCounter(IndVar, L, SE));
const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(SE->getSCEV(IndVar));
const SCEV *IVInit = AR->getStart();
// IVInit may be a pointer while IVCount is an integer when FindLoopCounter
@ -2311,13 +2311,13 @@ static Value *genLoopLimit(PHINode *IndVar, const SCEV *IVCount, Loop *L,
// IVInit integer and IVCount pointer would only occur if a canonical IV
// were generated on top of case #2, which is not expected.
assert(AR->getStepRecurrence(*SE)->isOne() && "only handles unit stride");
const SCEV *IVLimit = nullptr;
// For unit stride, IVCount = Start + BECount with 2's complement overflow.
// For non-zero Start, compute IVCount here.
if (AR->getStart()->isZero())
IVLimit = IVCount;
else {
assert(AR->getStepRecurrence(*SE)->isOne() && "only handles unit stride");
const SCEV *IVInit = AR->getStart();
// For integer IVs, truncate the IV before computing IVInit + BECount.