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Diffstat (limited to 'llvm/lib/Transforms/Utils/SimplifyCFG.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index f467de5..32b5855 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -4782,6 +4782,26 @@ static bool CasesAreContiguous(SmallVectorImpl<ConstantInt *> &Cases) { return true; } +static void createUnreachableSwitchDefault(SwitchInst *Switch, + DomTreeUpdater *DTU) { + LLVM_DEBUG(dbgs() << "SimplifyCFG: switch default is dead.\n"); + auto *BB = Switch->getParent(); + auto *OrigDefaultBlock = Switch->getDefaultDest(); + OrigDefaultBlock->removePredecessor(BB); + BasicBlock *NewDefaultBlock = BasicBlock::Create( + BB->getContext(), BB->getName() + ".unreachabledefault", BB->getParent(), + OrigDefaultBlock); + new UnreachableInst(Switch->getContext(), NewDefaultBlock); + Switch->setDefaultDest(&*NewDefaultBlock); + if (DTU) { + SmallVector<DominatorTree::UpdateType, 2> Updates; + Updates.push_back({DominatorTree::Insert, BB, &*NewDefaultBlock}); + if (!is_contained(successors(BB), OrigDefaultBlock)) + Updates.push_back({DominatorTree::Delete, BB, &*OrigDefaultBlock}); + DTU->applyUpdates(Updates); + } +} + /// Turn a switch with two reachable destinations into an integer range /// comparison and branch. bool SimplifyCFGOpt::TurnSwitchRangeIntoICmp(SwitchInst *SI, |