diff options
Diffstat (limited to 'llvm/lib/Analysis')
| -rw-r--r-- | llvm/lib/Analysis/LoopAccessAnalysis.cpp | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp index d7880cc2dfa..07ca4f513f6 100644 --- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp +++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp @@ -127,9 +127,25 @@ void RuntimePointerChecking::insert(Loop *Lp, Value *Ptr, bool WritePtr, const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Sc); assert(AR && "Invalid addrec expression"); const SCEV *Ex = SE->getBackedgeTakenCount(Lp); + + const SCEV *ScStart = AR->getStart(); const SCEV *ScEnd = AR->evaluateAtIteration(Ex, *SE); - Pointers.emplace_back(Ptr, AR->getStart(), ScEnd, WritePtr, DepSetId, ASId, - Sc); + const SCEV *Step = AR->getStepRecurrence(*SE); + + // For expressions with negative step, the upper bound is ScStart and the + // lower bound is ScEnd. + if (const SCEVConstant *CStep = dyn_cast<const SCEVConstant>(Step)) { + if (CStep->getValue()->isNegative()) + std::swap(ScStart, ScEnd); + } else { + // Fallback case: the step is not constant, but the we can still + // get the upper and lower bounds of the interval by using min/max + // expressions. + ScStart = SE->getUMinExpr(ScStart, ScEnd); + ScEnd = SE->getUMaxExpr(AR->getStart(), ScEnd); + } + + Pointers.emplace_back(Ptr, ScStart, ScEnd, WritePtr, DepSetId, ASId, Sc); } bool RuntimePointerChecking::needsChecking( |
