diff options
Diffstat (limited to 'llvm/lib/Transforms/Utils')
| -rw-r--r-- | llvm/lib/Transforms/Utils/PredicateInfo.cpp | 2 | ||||
| -rw-r--r-- | llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 27 |
2 files changed, 21 insertions, 8 deletions
diff --git a/llvm/lib/Transforms/Utils/PredicateInfo.cpp b/llvm/lib/Transforms/Utils/PredicateInfo.cpp index 371d9e6..a9ab3b3 100644 --- a/llvm/lib/Transforms/Utils/PredicateInfo.cpp +++ b/llvm/lib/Transforms/Utils/PredicateInfo.cpp @@ -819,7 +819,7 @@ public: OS << "]"; } else if (const auto *PS = dyn_cast<PredicateSwitch>(PI)) { OS << "; switch predicate info { CaseValue: " << *PS->CaseValue - << " Switch:" << *PS->Switch << " Edge: ["; + << " Edge: ["; PS->From->printAsOperand(OS); OS << ","; PS->To->printAsOperand(OS); diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index d831c27..c537be5c 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -7551,6 +7551,7 @@ static bool reduceSwitchRange(SwitchInst *SI, IRBuilder<> &Builder, /// log2(C)-indexed value table (instead of traditionally emitting a load of the /// address of the jump target, and indirectly jump to it). static bool simplifySwitchOfPowersOfTwo(SwitchInst *SI, IRBuilder<> &Builder, + DomTreeUpdater *DTU, const DataLayout &DL, const TargetTransformInfo &TTI) { Value *Condition = SI->getCondition(); @@ -7573,12 +7574,6 @@ static bool simplifySwitchOfPowersOfTwo(SwitchInst *SI, IRBuilder<> &Builder, if (SI->getNumCases() < 4) return false; - // We perform this optimization only for switches with - // unreachable default case. - // This assumtion will save us from checking if `Condition` is a power of two. - if (!SI->defaultDestUnreachable()) - return false; - // Check that switch cases are powers of two. SmallVector<uint64_t, 4> Values; for (const auto &Case : SI->cases()) { @@ -7598,6 +7593,24 @@ static bool simplifySwitchOfPowersOfTwo(SwitchInst *SI, IRBuilder<> &Builder, Builder.SetInsertPoint(SI); + if (!SI->defaultDestUnreachable()) { + // Let non-power-of-two inputs jump to the default case, when the latter is + // reachable. + auto *PopC = Builder.CreateUnaryIntrinsic(Intrinsic::ctpop, Condition); + auto *IsPow2 = Builder.CreateICmpEQ(PopC, ConstantInt::get(CondTy, 1)); + + auto *OrigBB = SI->getParent(); + auto *DefaultCaseBB = SI->getDefaultDest(); + BasicBlock *SplitBB = SplitBlock(OrigBB, SI, DTU); + auto It = OrigBB->getTerminator()->getIterator(); + BranchInst::Create(SplitBB, DefaultCaseBB, IsPow2, It); + It->eraseFromParent(); + + addPredecessorToBlock(DefaultCaseBB, OrigBB, SplitBB); + if (DTU) + DTU->applyUpdates({{DominatorTree::Insert, OrigBB, DefaultCaseBB}}); + } + // Replace each case with its trailing zeros number. for (auto &Case : SI->cases()) { auto *OrigValue = Case.getCaseValue(); @@ -7953,7 +7966,7 @@ bool SimplifyCFGOpt::simplifySwitch(SwitchInst *SI, IRBuilder<> &Builder) { Options.ConvertSwitchToLookupTable)) return requestResimplify(); - if (simplifySwitchOfPowersOfTwo(SI, Builder, DL, TTI)) + if (simplifySwitchOfPowersOfTwo(SI, Builder, DTU, DL, TTI)) return requestResimplify(); if (reduceSwitchRange(SI, Builder, DL, TTI)) |