diff options
Diffstat (limited to 'lib/Transforms/Scalar/JumpThreading.cpp')
| -rw-r--r-- | lib/Transforms/Scalar/JumpThreading.cpp | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp index 141c9938bf8be..2f1645433fb87 100644 --- a/lib/Transforms/Scalar/JumpThreading.cpp +++ b/lib/Transforms/Scalar/JumpThreading.cpp @@ -1454,6 +1454,9 @@ FindMostPopularDest(BasicBlock *BB, if (PredToDest.second) DestPopularity[PredToDest.second]++; + if (DestPopularity.empty()) + return nullptr; + // Find the most popular dest. DenseMap<BasicBlock*, unsigned>::iterator DPI = DestPopularity.begin(); BasicBlock *MostPopularDest = DPI->first; @@ -1629,8 +1632,20 @@ bool JumpThreadingPass::ProcessThreadableEdges(Value *Cond, BasicBlock *BB, // threadable destination (the common case) we can avoid this. BasicBlock *MostPopularDest = OnlyDest; - if (MostPopularDest == MultipleDestSentinel) + if (MostPopularDest == MultipleDestSentinel) { + // Remove any loop headers from the Dest list, ThreadEdge conservatively + // won't process them, but we might have other destination that are eligible + // and we still want to process. + erase_if(PredToDestList, + [&](const std::pair<BasicBlock *, BasicBlock *> &PredToDest) { + return LoopHeaders.count(PredToDest.second) != 0; + }); + + if (PredToDestList.empty()) + return false; + MostPopularDest = FindMostPopularDest(BB, PredToDestList); + } // Now that we know what the most popular destination is, factor all // predecessors that will jump to it into a single predecessor. |