diff options
Diffstat (limited to 'llvm/lib/Analysis/MustExecute.cpp')
| -rw-r--r-- | llvm/lib/Analysis/MustExecute.cpp | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/llvm/lib/Analysis/MustExecute.cpp b/llvm/lib/Analysis/MustExecute.cpp index e22831cd6a9..b616cd6f762 100644 --- a/llvm/lib/Analysis/MustExecute.cpp +++ b/llvm/lib/Analysis/MustExecute.cpp @@ -193,7 +193,8 @@ bool LoopSafetyInfo::allLoopPathsLeadToBlock(const Loop *CurLoop, SmallPtrSet<const BasicBlock *, 4> Predecessors; collectTransitivePredecessors(CurLoop, BB, Predecessors); - // Make sure that all successors of all predecessors of BB are either: + // Make sure that all successors of, all predecessors of BB which are not + // dominated by BB, are either: // 1) BB, // 2) Also predecessors of BB, // 3) Exit blocks which are not taken on 1st iteration. @@ -203,6 +204,12 @@ bool LoopSafetyInfo::allLoopPathsLeadToBlock(const Loop *CurLoop, // Predecessor block may throw, so it has a side exit. if (blockMayThrow(Pred)) return false; + + // BB dominates Pred, so if Pred runs, BB must run. + // This is true when Pred is a loop latch. + if (DT->dominates(BB, Pred)) + continue; + for (auto *Succ : successors(Pred)) if (CheckedSuccessors.insert(Succ).second && Succ != BB && !Predecessors.count(Succ)) |
