diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 18 | ||||
| -rw-r--r-- | llvm/lib/Transforms/Scalar/IndVarSimplify.cpp | 6 |
2 files changed, 18 insertions, 6 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index bfb0c0dfb60..163e1fe62d6 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -6606,7 +6606,7 @@ const SCEV *ScalarEvolution::getExitCount(const Loop *L, case Exact: return getBackedgeTakenInfo(L).getExact(ExitingBlock, this); case ConstantMaximum: - return getCouldNotCompute(); + return getBackedgeTakenInfo(L).getMax(ExitingBlock, this); }; llvm_unreachable("Invalid ExitCountKind!"); } @@ -6934,6 +6934,16 @@ ScalarEvolution::BackedgeTakenInfo::getExact(BasicBlock *ExitingBlock, return SE->getCouldNotCompute(); } +const SCEV * +ScalarEvolution::BackedgeTakenInfo::getMax(BasicBlock *ExitingBlock, + ScalarEvolution *SE) const { + for (auto &ENT : ExitNotTaken) + if (ENT.ExitingBlock == ExitingBlock && ENT.hasAlwaysTruePredicate()) + return ENT.MaxNotTaken; + + return SE->getCouldNotCompute(); +} + /// getMax - Get the max backedge taken count for the loop. const SCEV * ScalarEvolution::BackedgeTakenInfo::getMax(ScalarEvolution *SE) const { @@ -7025,13 +7035,15 @@ ScalarEvolution::BackedgeTakenInfo::BackedgeTakenInfo( BasicBlock *ExitBB = EEI.first; const ExitLimit &EL = EEI.second; if (EL.Predicates.empty()) - return ExitNotTakenInfo(ExitBB, EL.ExactNotTaken, nullptr); + return ExitNotTakenInfo(ExitBB, EL.ExactNotTaken, EL.MaxNotTaken, + nullptr); std::unique_ptr<SCEVUnionPredicate> Predicate(new SCEVUnionPredicate); for (auto *Pred : EL.Predicates) Predicate->add(Pred); - return ExitNotTakenInfo(ExitBB, EL.ExactNotTaken, std::move(Predicate)); + return ExitNotTakenInfo(ExitBB, EL.ExactNotTaken, EL.MaxNotTaken, + std::move(Predicate)); }); assert((isa<SCEVCouldNotCompute>(MaxCount) || isa<SCEVConstant>(MaxCount)) && "No point in having a non-constant max backedge taken count!"); diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp index 40cc3fc3af2..4520a468aca 100644 --- a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -2662,11 +2662,11 @@ static const SCEV* getMaxBackedgeTakenCount(ScalarEvolution &SE, // merge the max and exact information to approximate a version of // getConstantMaxBackedgeTakenCount which isn't restricted to just constants. SmallVector<const SCEV*, 4> ExitCounts; - const SCEV *MaxConstEC = SE.getConstantMaxBackedgeTakenCount(L); - if (!isa<SCEVCouldNotCompute>(MaxConstEC)) - ExitCounts.push_back(MaxConstEC); for (BasicBlock *ExitingBB : ExitingBlocks) { const SCEV *ExitCount = SE.getExitCount(L, ExitingBB); + if (isa<SCEVCouldNotCompute>(ExitCount)) + ExitCount = SE.getExitCount(L, ExitingBB, + ScalarEvolution::ConstantMaximum); if (!isa<SCEVCouldNotCompute>(ExitCount)) { assert(DT.dominates(ExitingBB, L->getLoopLatch()) && "We should only have known counts for exiting blocks that " |
