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ReMaterializeTrivialDef need to trim the live interval to the last kill if the copy kills the source register. This fixes uint64tof64.ll after ARM::MOVi is marked as isAsCheapAsAMove.
llvm-svn: 63853
This commit is contained in:
Evan Cheng
parent
87def37f67
commit
7ed9ce65f7
@ -450,6 +450,97 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
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return true;
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}
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/// isSameOrFallThroughBB - Return true if MBB == SuccMBB or MBB simply
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/// fallthoughs to SuccMBB.
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static bool isSameOrFallThroughBB(MachineBasicBlock *MBB,
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MachineBasicBlock *SuccMBB,
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const TargetInstrInfo *tii_) {
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if (MBB == SuccMBB)
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return true;
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MachineBasicBlock *TBB = 0, *FBB = 0;
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SmallVector<MachineOperand, 4> Cond;
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return !tii_->AnalyzeBranch(*MBB, TBB, FBB, Cond) && !TBB && !FBB &&
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MBB->isSuccessor(SuccMBB);
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}
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/// removeRange - Wrapper for LiveInterval::removeRange. This removes a range
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/// from a physical register live interval as well as from the live intervals
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/// of its sub-registers.
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static void removeRange(LiveInterval &li, unsigned Start, unsigned End,
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LiveIntervals *li_, const TargetRegisterInfo *tri_) {
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li.removeRange(Start, End, true);
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if (TargetRegisterInfo::isPhysicalRegister(li.reg)) {
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for (const unsigned* SR = tri_->getSubRegisters(li.reg); *SR; ++SR) {
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if (!li_->hasInterval(*SR))
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continue;
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LiveInterval &sli = li_->getInterval(*SR);
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unsigned RemoveEnd = Start;
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while (RemoveEnd != End) {
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LiveInterval::iterator LR = sli.FindLiveRangeContaining(Start);
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if (LR == sli.end())
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break;
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RemoveEnd = (LR->end < End) ? LR->end : End;
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sli.removeRange(Start, RemoveEnd, true);
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Start = RemoveEnd;
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}
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}
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}
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}
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/// TrimLiveIntervalToLastUse - If there is a last use in the same basic block
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/// as the copy instruction, trim the ive interval to the last use and return
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/// true.
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bool
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SimpleRegisterCoalescing::TrimLiveIntervalToLastUse(unsigned CopyIdx,
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MachineBasicBlock *CopyMBB,
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LiveInterval &li,
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const LiveRange *LR) {
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unsigned MBBStart = li_->getMBBStartIdx(CopyMBB);
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unsigned LastUseIdx;
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MachineOperand *LastUse = lastRegisterUse(LR->start, CopyIdx-1, li.reg,
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LastUseIdx);
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if (LastUse) {
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MachineInstr *LastUseMI = LastUse->getParent();
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if (!isSameOrFallThroughBB(LastUseMI->getParent(), CopyMBB, tii_)) {
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// r1024 = op
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// ...
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// BB1:
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// = r1024
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//
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// BB2:
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// r1025<dead> = r1024<kill>
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if (MBBStart < LR->end)
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removeRange(li, MBBStart, LR->end, li_, tri_);
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return true;
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}
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// There are uses before the copy, just shorten the live range to the end
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// of last use.
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LastUse->setIsKill();
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removeRange(li, li_->getDefIndex(LastUseIdx), LR->end, li_, tri_);
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unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
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if (tii_->isMoveInstr(*LastUseMI, SrcReg, DstReg, SrcSubIdx, DstSubIdx) &&
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DstReg == li.reg) {
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// Last use is itself an identity code.
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int DeadIdx = LastUseMI->findRegisterDefOperandIdx(li.reg, false, tri_);
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LastUseMI->getOperand(DeadIdx).setIsDead();
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}
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return true;
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}
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// Is it livein?
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if (LR->start <= MBBStart && LR->end > MBBStart) {
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if (LR->start == 0) {
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assert(TargetRegisterInfo::isPhysicalRegister(li.reg));
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// Live-in to the function but dead. Remove it from entry live-in set.
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mf_->begin()->removeLiveIn(li.reg);
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}
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// FIXME: Shorten intervals in BBs that reaches this BB.
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}
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return false;
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}
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/// ReMaterializeTrivialDef - If the source of a copy is defined by a trivial
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/// computation, replace the copy by rematerialize the definition.
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bool SimpleRegisterCoalescing::ReMaterializeTrivialDef(LiveInterval &SrcInt,
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@ -485,7 +576,12 @@ bool SimpleRegisterCoalescing::ReMaterializeTrivialDef(LiveInterval &SrcInt,
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}
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}
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// If copy kills the source register, find the last use and propagate
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// kill.
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MachineBasicBlock *MBB = CopyMI->getParent();
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if (CopyMI->killsRegister(SrcInt.reg))
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TrimLiveIntervalToLastUse(CopyIdx, MBB, SrcInt, SrcLR);
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MachineBasicBlock::iterator MII = next(MachineBasicBlock::iterator(CopyMI));
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CopyMI->removeFromParent();
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tii_->reMaterialize(*MBB, MII, DstReg, DefMI);
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@ -660,30 +756,6 @@ void SimpleRegisterCoalescing::RemoveUnnecessaryKills(unsigned Reg,
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}
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}
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/// removeRange - Wrapper for LiveInterval::removeRange. This removes a range
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/// from a physical register live interval as well as from the live intervals
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/// of its sub-registers.
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static void removeRange(LiveInterval &li, unsigned Start, unsigned End,
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LiveIntervals *li_, const TargetRegisterInfo *tri_) {
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li.removeRange(Start, End, true);
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if (TargetRegisterInfo::isPhysicalRegister(li.reg)) {
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for (const unsigned* SR = tri_->getSubRegisters(li.reg); *SR; ++SR) {
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if (!li_->hasInterval(*SR))
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continue;
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LiveInterval &sli = li_->getInterval(*SR);
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unsigned RemoveEnd = Start;
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while (RemoveEnd != End) {
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LiveInterval::iterator LR = sli.FindLiveRangeContaining(Start);
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if (LR == sli.end())
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break;
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RemoveEnd = (LR->end < End) ? LR->end : End;
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sli.removeRange(Start, RemoveEnd, true);
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Start = RemoveEnd;
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}
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}
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}
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}
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/// removeIntervalIfEmpty - Check if the live interval of a physical register
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/// is empty, if so remove it and also remove the empty intervals of its
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/// sub-registers. Return true if live interval is removed.
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@ -752,19 +824,6 @@ static void PropagateDeadness(LiveInterval &li, MachineInstr *CopyMI,
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}
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}
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/// isSameOrFallThroughBB - Return true if MBB == SuccMBB or MBB simply
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/// fallthoughs to SuccMBB.
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static bool isSameOrFallThroughBB(MachineBasicBlock *MBB,
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MachineBasicBlock *SuccMBB,
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const TargetInstrInfo *tii_) {
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if (MBB == SuccMBB)
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return true;
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MachineBasicBlock *TBB = 0, *FBB = 0;
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SmallVector<MachineOperand, 4> Cond;
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return !tii_->AnalyzeBranch(*MBB, TBB, FBB, Cond) && !TBB && !FBB &&
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MBB->isSuccessor(SuccMBB);
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}
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/// ShortenDeadCopySrcLiveRange - Shorten a live range as it's artificially
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/// extended by a dead copy. Mark the last use (if any) of the val# as kill as
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/// ends the live range there. If there isn't another use, then this live range
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@ -796,49 +855,10 @@ SimpleRegisterCoalescing::ShortenDeadCopySrcLiveRange(LiveInterval &li,
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// More uses past this copy? Nothing to do.
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return false;
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MachineBasicBlock *CopyMBB = CopyMI->getParent();
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unsigned MBBStart = li_->getMBBStartIdx(CopyMBB);
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unsigned LastUseIdx;
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MachineOperand *LastUse = lastRegisterUse(LR->start, CopyIdx-1, li.reg,
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LastUseIdx);
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if (LastUse) {
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MachineInstr *LastUseMI = LastUse->getParent();
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if (!isSameOrFallThroughBB(LastUseMI->getParent(), CopyMBB, tii_)) {
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// r1024 = op
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// ...
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// BB1:
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// = r1024
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//
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// BB2:
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// r1025<dead> = r1024<kill>
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if (MBBStart < LR->end)
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removeRange(li, MBBStart, LR->end, li_, tri_);
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return false;
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}
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// There are uses before the copy, just shorten the live range to the end
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// of last use.
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LastUse->setIsKill();
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removeRange(li, li_->getDefIndex(LastUseIdx), LR->end, li_, tri_);
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unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
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if (tii_->isMoveInstr(*LastUseMI, SrcReg, DstReg, SrcSubIdx, DstSubIdx) &&
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DstReg == li.reg) {
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// Last use is itself an identity code.
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int DeadIdx = LastUseMI->findRegisterDefOperandIdx(li.reg, false, tri_);
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LastUseMI->getOperand(DeadIdx).setIsDead();
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}
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// If there is a last use in the same bb, we can't remove the live range.
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// Shorten the live interval and return.
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if (TrimLiveIntervalToLastUse(CopyIdx, CopyMI->getParent(), li, LR))
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return false;
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}
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// Is it livein?
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if (LR->start <= MBBStart && LR->end > MBBStart) {
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if (LR->start == 0) {
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assert(TargetRegisterInfo::isPhysicalRegister(li.reg));
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// Live-in to the function but dead. Remove it from entry live-in set.
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mf_->begin()->removeLiveIn(li.reg);
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}
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// FIXME: Shorten intervals in BBs that reaches this BB.
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}
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if (LR->valno->def == RemoveStart)
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// If the def MI defines the val#, propagate the dead marker.
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@ -196,6 +196,15 @@ namespace llvm {
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bool RemoveCopyByCommutingDef(LiveInterval &IntA, LiveInterval &IntB,
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MachineInstr *CopyMI);
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/// TrimLiveIntervalToLastUse - If there is a last use in the same basic
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/// block as the copy instruction, trim the ive interval to the last use
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/// and return true.
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bool TrimLiveIntervalToLastUse(unsigned CopyIdx,
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MachineBasicBlock *CopyMBB,
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LiveInterval &li, const LiveRange *LR);
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/// ReMaterializeTrivialDef - If the source of a copy is defined by a trivial
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/// computation, replace the copy by rematerialize the definition.
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bool ReMaterializeTrivialDef(LiveInterval &SrcInt, unsigned DstReg,
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MachineInstr *CopyMI);
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