diff options
Diffstat (limited to 'llvm/lib/CodeGen/MachineBasicBlock.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/MachineBasicBlock.cpp | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/llvm/lib/CodeGen/MachineBasicBlock.cpp b/llvm/lib/CodeGen/MachineBasicBlock.cpp index bc1df26..1cb57a4 100644 --- a/llvm/lib/CodeGen/MachineBasicBlock.cpp +++ b/llvm/lib/CodeGen/MachineBasicBlock.cpp @@ -1180,7 +1180,7 @@ MachineBasicBlock *MachineBasicBlock::SplitCriticalEdge( MachineBasicBlock *MachineBasicBlock::SplitCriticalEdge( MachineBasicBlock *Succ, const SplitCriticalEdgeAnalyses &Analyses, std::vector<SparseBitVector<>> *LiveInSets, MachineDomTreeUpdater *MDTU) { - if (!canSplitCriticalEdge(Succ)) + if (!canSplitCriticalEdge(Succ, Analyses.MLI)) return nullptr; MachineFunction *MF = getParent(); @@ -1408,8 +1408,8 @@ MachineBasicBlock *MachineBasicBlock::SplitCriticalEdge( return NMBB; } -bool MachineBasicBlock::canSplitCriticalEdge( - const MachineBasicBlock *Succ) const { +bool MachineBasicBlock::canSplitCriticalEdge(const MachineBasicBlock *Succ, + const MachineLoopInfo *MLI) const { // Splitting the critical edge to a landing pad block is non-trivial. Don't do // it in this generic function. if (Succ->isEHPad()) @@ -1423,8 +1423,17 @@ bool MachineBasicBlock::canSplitCriticalEdge( const MachineFunction *MF = getParent(); // Performance might be harmed on HW that implements branching using exec mask // where both sides of the branches are always executed. - if (MF->getTarget().requiresStructuredCFG()) + + if (MF->getTarget().requiresStructuredCFG()) { + // If `Succ` is a loop header, splitting the critical edge will not + // break structured CFG. + if (MLI) { + const MachineLoop *L = MLI->getLoopFor(Succ); + return L && L->getHeader() == Succ; + } + return false; + } // Do we have an Indirect jump with a jumptable that we can rewrite? int JTI = findJumpTableIndex(*this); |