diff options
| -rw-r--r-- | llvm/include/llvm/Analysis/MustExecute.h | 7 | ||||
| -rw-r--r-- | llvm/lib/Analysis/MustExecute.cpp | 31 |
2 files changed, 27 insertions, 11 deletions
diff --git a/llvm/include/llvm/Analysis/MustExecute.h b/llvm/include/llvm/Analysis/MustExecute.h index 89774395415..40a02735d1b 100644 --- a/llvm/include/llvm/Analysis/MustExecute.h +++ b/llvm/include/llvm/Analysis/MustExecute.h @@ -49,6 +49,13 @@ class LoopSafetyInfo { // may throw. bool HeaderMayThrow = false; // Same as previous, but specific to loop header + /// Collect all blocks from \p CurLoop which lie on all possible paths from + /// the header of \p CurLoop (inclusive) to BB (exclusive) into the set + /// \p Predecessors. If \p BB is the header, \p Predecessors will be empty. + void collectTransitivePredecessors( + const Loop *CurLoop, const BasicBlock *BB, + SmallPtrSetImpl<const BasicBlock *> &Predecessors) const; + public: // Used to update funclet bundle operands. DenseMap<BasicBlock *, ColorVector> BlockColors; diff --git a/llvm/lib/Analysis/MustExecute.cpp b/llvm/lib/Analysis/MustExecute.cpp index ab091005a20..79ec8e400c0 100644 --- a/llvm/lib/Analysis/MustExecute.cpp +++ b/llvm/lib/Analysis/MustExecute.cpp @@ -98,19 +98,13 @@ static bool CanProveNotTakenFirstIteration(const BasicBlock *ExitBlock, return SimpleCst->isAllOnesValue(); } - -bool LoopSafetyInfo::allLoopPathsLeadToBlock(const Loop *CurLoop, - const BasicBlock *BB, - const DominatorTree *DT) const { +void LoopSafetyInfo::collectTransitivePredecessors( + const Loop *CurLoop, const BasicBlock *BB, + SmallPtrSetImpl<const BasicBlock *> &Predecessors) const { + assert(Predecessors.empty() && "Garbage in predecessors set?"); assert(CurLoop->contains(BB) && "Should only be called for loop blocks!"); - - // Fast path: header is always reached once the loop is entered. if (BB == CurLoop->getHeader()) - return true; - - // Collect all transitive predecessors of BB in the same loop. This set will - // be a subset of the blocks within the loop. - SmallPtrSet<const BasicBlock *, 4> Predecessors; + return; SmallVector<const BasicBlock *, 4> WorkList; for (auto *Pred : predecessors(BB)) { Predecessors.insert(Pred); @@ -132,6 +126,21 @@ bool LoopSafetyInfo::allLoopPathsLeadToBlock(const Loop *CurLoop, if (Predecessors.insert(PredPred).second) WorkList.push_back(PredPred); } +} + +bool LoopSafetyInfo::allLoopPathsLeadToBlock(const Loop *CurLoop, + const BasicBlock *BB, + const DominatorTree *DT) const { + assert(CurLoop->contains(BB) && "Should only be called for loop blocks!"); + + // Fast path: header is always reached once the loop is entered. + if (BB == CurLoop->getHeader()) + return true; + + // Collect all transitive predecessors of BB in the same loop. This set will + // be a subset of the blocks within the loop. + SmallPtrSet<const BasicBlock *, 4> Predecessors; + collectTransitivePredecessors(CurLoop, BB, Predecessors); // Make sure that all successors of all predecessors of BB are either: // 1) BB, |
