diff options
Diffstat (limited to 'llvm/lib/CodeGen/MachineCSE.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/MachineCSE.cpp | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/llvm/lib/CodeGen/MachineCSE.cpp b/llvm/lib/CodeGen/MachineCSE.cpp index 29604089ad8..21b9c5aa063 100644 --- a/llvm/lib/CodeGen/MachineCSE.cpp +++ b/llvm/lib/CodeGen/MachineCSE.cpp @@ -580,8 +580,15 @@ bool MachineCSE::ProcessBlock(MachineBasicBlock *MBB) { // Actually perform the elimination. if (DoCSE) { for (unsigned i = 0, e = CSEPairs.size(); i != e; ++i) { - MRI->replaceRegWith(CSEPairs[i].first, CSEPairs[i].second); - MRI->clearKillFlags(CSEPairs[i].second); + unsigned OldReg = CSEPairs[i].first; + unsigned NewReg = CSEPairs[i].second; + // OldReg may have been unused but is used now, clear the Dead flag + MachineInstr *Def = MRI->getUniqueVRegDef(NewReg); + assert(Def != nullptr && "CSEd register has no unique definition?"); + Def->clearRegisterDeads(NewReg); + // Replace with NewReg and clear kill flags which may be wrong now. + MRI->replaceRegWith(OldReg, NewReg); + MRI->clearKillFlags(NewReg); } // Go through implicit defs of CSMI and MI, if a def is not dead at MI, |
