-/// isSameOrFallThroughBB - Return true if MBB == SuccMBB or MBB simply
-/// fallthoughs to SuccMBB.
-static bool isSameOrFallThroughBB(MachineBasicBlock *MBB,
- MachineBasicBlock *SuccMBB,
- const TargetInstrInfo *tii_) {
- if (MBB == SuccMBB)
- return true;
- MachineBasicBlock *TBB = 0, *FBB = 0;
- SmallVector<MachineOperand, 4> Cond;
- return !tii_->AnalyzeBranch(*MBB, TBB, FBB, Cond) && !TBB && !FBB &&
- MBB->isSuccessor(SuccMBB);
-}
-
-/// removeRange - Wrapper for LiveInterval::removeRange. This removes a range
-/// from a physical register live interval as well as from the live intervals
-/// of its sub-registers.
-static void removeRange(LiveInterval &li,
- SlotIndex Start, SlotIndex End,
- LiveIntervals *li_, const TargetRegisterInfo *tri_) {
- li.removeRange(Start, End, true);
- if (TargetRegisterInfo::isPhysicalRegister(li.reg)) {
- for (const unsigned* SR = tri_->getSubRegisters(li.reg); *SR; ++SR) {
- if (!li_->hasInterval(*SR))
- continue;
- LiveInterval &sli = li_->getInterval(*SR);
- SlotIndex RemoveStart = Start;
- SlotIndex RemoveEnd = Start;
-
- while (RemoveEnd != End) {
- LiveInterval::iterator LR = sli.FindLiveRangeContaining(RemoveStart);
- if (LR == sli.end())
- break;
- RemoveEnd = (LR->end < End) ? LR->end : End;
- sli.removeRange(RemoveStart, RemoveEnd, true);
- RemoveStart = RemoveEnd;
- }
- }
- }
-}
-
-/// TrimLiveIntervalToLastUse - If there is a last use in the same basic block
-/// as the copy instruction, trim the live interval to the last use and return
-/// true.
-bool
-SimpleRegisterCoalescing::TrimLiveIntervalToLastUse(SlotIndex CopyIdx,
- MachineBasicBlock *CopyMBB,
- LiveInterval &li,
- const LiveRange *LR) {
- SlotIndex MBBStart = li_->getMBBStartIdx(CopyMBB);
- SlotIndex LastUseIdx;
- MachineOperand *LastUse =
- lastRegisterUse(LR->start, CopyIdx.getPrevSlot(), li.reg, LastUseIdx);
- if (LastUse) {
- MachineInstr *LastUseMI = LastUse->getParent();
- if (!isSameOrFallThroughBB(LastUseMI->getParent(), CopyMBB, tii_)) {
- // r1024 = op
- // ...
- // BB1:
- // = r1024
- //
- // BB2:
- // r1025<dead> = r1024<kill>
- if (MBBStart < LR->end)
- removeRange(li, MBBStart, LR->end, li_, tri_);
- return true;
- }
-
- // There are uses before the copy, just shorten the live range to the end
- // of last use.
- LastUse->setIsKill();
- removeRange(li, LastUseIdx.getDefIndex(), LR->end, li_, tri_);
- if (LastUseMI->isCopy()) {
- MachineOperand &DefMO = LastUseMI->getOperand(0);
- if (DefMO.getReg() == li.reg && !DefMO.getSubReg())
- DefMO.setIsDead();
- }
- unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
- if (tii_->isMoveInstr(*LastUseMI, SrcReg, DstReg, SrcSubIdx, DstSubIdx) &&
- DstReg == li.reg && DstSubIdx == 0) {
- // Last use is itself an identity code.
- int DeadIdx = LastUseMI->findRegisterDefOperandIdx(li.reg,
- false, false, tri_);
- LastUseMI->getOperand(DeadIdx).setIsDead();
- }
- return true;
- }
-
- // Is it livein?
- if (LR->start <= MBBStart && LR->end > MBBStart) {
- if (LR->start == li_->getZeroIndex()) {
- assert(TargetRegisterInfo::isPhysicalRegister(li.reg));
- // Live-in to the function but dead. Remove it from entry live-in set.
- mf_->begin()->removeLiveIn(li.reg);
- }
- // FIXME: Shorten intervals in BBs that reaches this BB.
- }
-
- return false;
-}
-