diff options
Diffstat (limited to 'lib/CodeGen/SimpleRegisterCoalescing.cpp')
| -rw-r--r-- | lib/CodeGen/SimpleRegisterCoalescing.cpp | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp index 870fcc4408..8ae36db115 100644 --- a/lib/CodeGen/SimpleRegisterCoalescing.cpp +++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp @@ -283,6 +283,17 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA, if (HasOtherReachingDefs(IntA, IntB, AValNo, BValNo)) return false; + // If some of the uses of IntA.reg is already coalesced away, return false. + // It's not possible to determine whether it's safe to perform the coalescing. + for (MachineRegisterInfo::use_iterator UI = mri_->use_begin(IntA.reg), + UE = mri_->use_end(); UI != UE; ++UI) { + MachineInstr *UseMI = &*UI; + unsigned UseIdx = li_->getInstructionIndex(UseMI); + LiveInterval::iterator ULR = IntA.FindLiveRangeContaining(UseIdx); + if (ULR->valno == AValNo && JoinedCopies.count(UseMI)) + return false; + } + // At this point we have decided that it is legal to do this // transformation. Start by commuting the instruction. MachineBasicBlock *MBB = DefMI->getParent(); @@ -323,8 +334,7 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA, MachineInstr *UseMI = &*UI; ++UI; if (JoinedCopies.count(UseMI)) - // It'll no longer be "joined" after the change. - JoinedCopies.erase(UseMI); + continue; unsigned UseIdx = li_->getInstructionIndex(UseMI); LiveInterval::iterator ULR = IntA.FindLiveRangeContaining(UseIdx); if (ULR->valno != AValNo) |