diff options
| author | Nikita Popov <npopov@redhat.com> | 2022-07-18 12:25:26 +0200 |
|---|---|---|
| committer | Nikita Popov <npopov@redhat.com> | 2022-07-18 12:26:29 +0200 |
| commit | 8201e3ef5c84561260218bc041209611aac690e3 (patch) | |
| tree | 6c1603fe96a79038ac2eaa82cc9a13e454f09b77 /llvm/lib/Transforms/Utils/BasicBlockUtils.cpp | |
| parent | 9c66c02e2e7e4dcf519239fed4d2e88fc27a228c (diff) | |
| download | llvm-8201e3ef5c84561260218bc041209611aac690e3.zip llvm-8201e3ef5c84561260218bc041209611aac690e3.tar.gz llvm-8201e3ef5c84561260218bc041209611aac690e3.tar.bz2 | |
[BasicBlockUtils] Don't drop callbr with unique successor
As callbr is now allowed to have duplicate destinations, we can
have a callbr with a unique successor. Make sure it doesn't get
dropped, as we still need to preserve the side-effect.
Diffstat (limited to 'llvm/lib/Transforms/Utils/BasicBlockUtils.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Utils/BasicBlockUtils.cpp | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp index 079b2fc..b08bf48 100644 --- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp +++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp @@ -188,8 +188,10 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, DomTreeUpdater *DTU, // Don't break self-loops. if (PredBB == BB) return false; - // Don't break unwinding instructions. - if (PredBB->getTerminator()->isExceptionalTerminator()) + + // Don't break unwinding instructions or terminators with other side-effects. + Instruction *PTI = PredBB->getTerminator(); + if (PTI->isExceptionalTerminator() || PTI->mayHaveSideEffects()) return false; // Can't merge if there are multiple distinct successors. @@ -202,7 +204,7 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, DomTreeUpdater *DTU, BasicBlock *NewSucc = nullptr; unsigned FallThruPath; if (PredecessorWithTwoSuccessors) { - if (!(PredBB_BI = dyn_cast<BranchInst>(PredBB->getTerminator()))) + if (!(PredBB_BI = dyn_cast<BranchInst>(PTI))) return false; BranchInst *BB_JmpI = dyn_cast<BranchInst>(BB->getTerminator()); if (!BB_JmpI || !BB_JmpI->isUnconditional()) @@ -256,7 +258,6 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, DomTreeUpdater *DTU, Updates.push_back({DominatorTree::Delete, PredBB, BB}); } - Instruction *PTI = PredBB->getTerminator(); Instruction *STI = BB->getTerminator(); Instruction *Start = &*BB->begin(); // If there's nothing to move, mark the starting instruction as the last |