diff options
Diffstat (limited to 'lib/CodeGen/MachineBasicBlock.cpp')
| -rw-r--r-- | lib/CodeGen/MachineBasicBlock.cpp | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp index d4f901d793..31d12ebdc4 100644 --- a/lib/CodeGen/MachineBasicBlock.cpp +++ b/lib/CodeGen/MachineBasicBlock.cpp @@ -450,14 +450,24 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { MachineFunction *MF = getParent(); DebugLoc dl; // FIXME: this is nowhere - // We may need to update this's terminator, but we can't do that if AnalyzeBranch - // fails. If this uses a jump table, we won't touch it. + // We may need to update this's terminator, but we can't do that if + // AnalyzeBranch fails. If this uses a jump table, we won't touch it. const TargetInstrInfo *TII = MF->getTarget().getInstrInfo(); MachineBasicBlock *TBB = 0, *FBB = 0; SmallVector<MachineOperand, 4> Cond; if (TII->AnalyzeBranch(*this, TBB, FBB, Cond)) return NULL; + // Avoid bugpoint weirdness: A block may end with a conditional branch but + // jumps to the same MBB is either case. We have duplicate CFG edges in that + // case that we can't handle. Since this never happens in properly optimized + // code, just skip those edges. + if (TBB && TBB == FBB) { + DEBUG(dbgs() << "Won't split critical edge after degenerate BB#" + << getNumber() << '\n'); + return NULL; + } + MachineBasicBlock *NMBB = MF->CreateMachineBasicBlock(); MF->insert(llvm::next(MachineFunction::iterator(this)), NMBB); DEBUG(dbgs() << "Splitting critical edge:" |