diff options
Diffstat (limited to 'lib/Transforms/Utils/SimplifyCFG.cpp')
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 23 |
1 files changed, 16 insertions, 7 deletions
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index 2f575b9d50272..f86e97b6cc72f 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -60,6 +60,7 @@ #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/KnownBits.h" #include "llvm/Support/MathExtras.h" #include "llvm/Support/raw_ostream.h" #include "llvm/Transforms/Utils/BasicBlockUtils.h" @@ -3055,6 +3056,15 @@ static bool mergeConditionalStores(BranchInst *PBI, BranchInst *QBI) { BasicBlock *QFB = QBI->getSuccessor(1); BasicBlock *PostBB = QFB->getSingleSuccessor(); + // Make sure we have a good guess for PostBB. If QTB's only successor is + // QFB, then QFB is a better PostBB. + if (QTB->getSingleSuccessor() == QFB) + PostBB = QFB; + + // If we couldn't find a good PostBB, stop. + if (!PostBB) + return false; + bool InvertPCond = false, InvertQCond = false; // Canonicalize fallthroughs to the true branches. if (PFB == QBI->getParent()) { @@ -3079,8 +3089,7 @@ static bool mergeConditionalStores(BranchInst *PBI, BranchInst *QBI) { auto HasOnePredAndOneSucc = [](BasicBlock *BB, BasicBlock *P, BasicBlock *S) { return BB->getSinglePredecessor() == P && BB->getSingleSuccessor() == S; }; - if (!PostBB || - !HasOnePredAndOneSucc(PFB, PBI->getParent(), QBI->getParent()) || + if (!HasOnePredAndOneSucc(PFB, PBI->getParent(), QBI->getParent()) || !HasOnePredAndOneSucc(QFB, QBI->getParent(), PostBB)) return false; if ((PTB && !HasOnePredAndOneSucc(PTB, PBI->getParent(), QBI->getParent())) || @@ -3746,7 +3755,7 @@ bool SimplifyCFGOpt::SimplifyCommonResume(ResumeInst *RI) { if (!isa<DbgInfoIntrinsic>(I)) return false; - SmallSet<BasicBlock *, 4> TrivialUnwindBlocks; + SmallSetVector<BasicBlock *, 4> TrivialUnwindBlocks; auto *PhiLPInst = cast<PHINode>(RI->getValue()); // Check incoming blocks to see if any of them are trivial. @@ -4359,8 +4368,8 @@ static bool EliminateDeadSwitchCases(SwitchInst *SI, AssumptionCache *AC, const DataLayout &DL) { Value *Cond = SI->getCondition(); unsigned Bits = Cond->getType()->getIntegerBitWidth(); - APInt KnownZero(Bits, 0), KnownOne(Bits, 0); - computeKnownBits(Cond, KnownZero, KnownOne, DL, 0, AC, SI); + KnownBits Known(Bits); + computeKnownBits(Cond, Known, DL, 0, AC, SI); // We can also eliminate cases by determining that their values are outside of // the limited range of the condition based on how many significant (non-sign) @@ -4372,7 +4381,7 @@ static bool EliminateDeadSwitchCases(SwitchInst *SI, AssumptionCache *AC, SmallVector<ConstantInt *, 8> DeadCases; for (auto &Case : SI->cases()) { APInt CaseVal = Case.getCaseValue()->getValue(); - if ((CaseVal & KnownZero) != 0 || (CaseVal & KnownOne) != KnownOne || + if (Known.Zero.intersects(CaseVal) || !Known.One.isSubsetOf(CaseVal) || (CaseVal.getMinSignedBits() > MaxSignificantBitsInCond)) { DeadCases.push_back(Case.getCaseValue()); DEBUG(dbgs() << "SimplifyCFG: switch case " << CaseVal << " is dead.\n"); @@ -4386,7 +4395,7 @@ static bool EliminateDeadSwitchCases(SwitchInst *SI, AssumptionCache *AC, bool HasDefault = !isa<UnreachableInst>(SI->getDefaultDest()->getFirstNonPHIOrDbg()); const unsigned NumUnknownBits = - Bits - (KnownZero | KnownOne).countPopulation(); + Bits - (Known.Zero | Known.One).countPopulation(); assert(NumUnknownBits <= Bits); if (HasDefault && DeadCases.empty() && NumUnknownBits < 64 /* avoid overflow */ && |