+ // First collect all the def / use in this live range that will be rewritten.
+ // Make sure they are sorted according to instruction index.
+ std::vector<RewriteInfo> RewriteMIs;
+ for (MachineRegisterInfo::reg_iterator ri = mri_->reg_begin(li.reg),
+ re = mri_->reg_end(); ri != re; ) {
+ MachineInstr *MI = &*ri;
+ MachineOperand &O = ri.getOperand();
+ ++ri;
+ assert(!O.isImplicit() && "Spilling register that's used as implicit use?");
+ unsigned index = getInstructionIndex(MI);
+ if (index < start || index >= end)
+ continue;
+ RewriteMIs.push_back(RewriteInfo(index, MI, O.isUse(), O.isDef()));
+ }
+ std::sort(RewriteMIs.begin(), RewriteMIs.end(), RewriteInfoCompare());
+
+ unsigned ImpUse = DefIsReMat ? getReMatImplicitUse(li, ReMatDefMI) : 0;
+ // Now rewrite the defs and uses.
+ for (unsigned i = 0, e = RewriteMIs.size(); i != e; ) {
+ RewriteInfo &rwi = RewriteMIs[i];
+ ++i;
+ unsigned index = rwi.Index;
+ bool MIHasUse = rwi.HasUse;
+ bool MIHasDef = rwi.HasDef;
+ MachineInstr *MI = rwi.MI;
+ // If MI def and/or use the same register multiple times, then there
+ // are multiple entries.
+ unsigned NumUses = MIHasUse;
+ while (i != e && RewriteMIs[i].MI == MI) {
+ assert(RewriteMIs[i].Index == index);
+ bool isUse = RewriteMIs[i].HasUse;
+ if (isUse) ++NumUses;
+ MIHasUse |= isUse;
+ MIHasDef |= RewriteMIs[i].HasDef;
+ ++i;
+ }
+ MachineBasicBlock *MBB = MI->getParent();
+
+ if (ImpUse && MI != ReMatDefMI) {
+ // Re-matting an instruction with virtual register use. Update the
+ // register interval's spill weight to HUGE_VALF to prevent it from
+ // being spilled.
+ LiveInterval &ImpLi = getInterval(ImpUse);
+ ImpLi.weight = HUGE_VALF;
+ }
+
+ unsigned MBBId = MBB->getNumber();
+ unsigned ThisVReg = 0;
+ if (TrySplit) {
+ std::map<unsigned,unsigned>::const_iterator NVI = MBBVRegsMap.find(MBBId);
+ if (NVI != MBBVRegsMap.end()) {
+ ThisVReg = NVI->second;
+ // One common case:
+ // x = use
+ // ...
+ // ...
+ // def = ...
+ // = use
+ // It's better to start a new interval to avoid artifically
+ // extend the new interval.
+ if (MIHasDef && !MIHasUse) {
+ MBBVRegsMap.erase(MBB->getNumber());
+ ThisVReg = 0;
+ }
+ }
+ }
+
+ bool IsNew = ThisVReg == 0;
+ if (IsNew) {
+ // This ends the previous live interval. If all of its def / use
+ // can be folded, give it a low spill weight.
+ if (NewVReg && TrySplit && AllCanFold) {
+ LiveInterval &nI = getOrCreateInterval(NewVReg);
+ nI.weight /= 10.0F;
+ }
+ AllCanFold = true;
+ }
+ NewVReg = ThisVReg;
+
+ bool HasDef = false;
+ bool HasUse = false;
+ bool CanFold = rewriteInstructionForSpills(li, I->valno, TrySplit,
+ index, end, MI, ReMatOrigDefMI, ReMatDefMI,
+ Slot, LdSlot, isLoad, isLoadSS, DefIsReMat,
+ CanDelete, vrm, rc, ReMatIds, loopInfo, NewVReg,
+ ImpUse, HasDef, HasUse, MBBVRegsMap, NewLIs, SSWeight);
+ if (!HasDef && !HasUse)
+ continue;
+
+ AllCanFold &= CanFold;
+
+ // Update weight of spill interval.
+ LiveInterval &nI = getOrCreateInterval(NewVReg);
+ if (!TrySplit) {
+ // The spill weight is now infinity as it cannot be spilled again.
+ nI.weight = HUGE_VALF;
+ continue;
+ }
+
+ // Keep track of the last def and first use in each MBB.
+ if (HasDef) {
+ if (MI != ReMatOrigDefMI || !CanDelete) {
+ bool HasKill = false;
+ if (!HasUse)
+ HasKill = anyKillInMBBAfterIdx(li, I->valno, MBB, getDefIndex(index));
+ else {
+ // If this is a two-address code, then this index starts a new VNInfo.
+ const VNInfo *VNI = li.findDefinedVNInfo(getDefIndex(index));
+ if (VNI)
+ HasKill = anyKillInMBBAfterIdx(li, VNI, MBB, getDefIndex(index));
+ }
+ std::map<unsigned, std::vector<SRInfo> >::iterator SII =
+ SpillIdxes.find(MBBId);
+ if (!HasKill) {
+ if (SII == SpillIdxes.end()) {
+ std::vector<SRInfo> S;
+ S.push_back(SRInfo(index, NewVReg, true));
+ SpillIdxes.insert(std::make_pair(MBBId, S));
+ } else if (SII->second.back().vreg != NewVReg) {
+ SII->second.push_back(SRInfo(index, NewVReg, true));
+ } else if ((int)index > SII->second.back().index) {
+ // If there is an earlier def and this is a two-address
+ // instruction, then it's not possible to fold the store (which
+ // would also fold the load).
+ SRInfo &Info = SII->second.back();
+ Info.index = index;
+ Info.canFold = !HasUse;
+ }
+ SpillMBBs.set(MBBId);
+ } else if (SII != SpillIdxes.end() &&
+ SII->second.back().vreg == NewVReg &&
+ (int)index > SII->second.back().index) {
+ // There is an earlier def that's not killed (must be two-address).
+ // The spill is no longer needed.
+ SII->second.pop_back();
+ if (SII->second.empty()) {
+ SpillIdxes.erase(MBBId);
+ SpillMBBs.reset(MBBId);
+ }
+ }
+ }
+ }
+
+ if (HasUse) {
+ std::map<unsigned, std::vector<SRInfo> >::iterator SII =
+ SpillIdxes.find(MBBId);
+ if (SII != SpillIdxes.end() &&
+ SII->second.back().vreg == NewVReg &&
+ (int)index > SII->second.back().index)
+ // Use(s) following the last def, it's not safe to fold the spill.
+ SII->second.back().canFold = false;
+ std::map<unsigned, std::vector<SRInfo> >::iterator RII =
+ RestoreIdxes.find(MBBId);
+ if (RII != RestoreIdxes.end() && RII->second.back().vreg == NewVReg)
+ // If we are splitting live intervals, only fold if it's the first
+ // use and there isn't another use later in the MBB.
+ RII->second.back().canFold = false;
+ else if (IsNew) {
+ // Only need a reload if there isn't an earlier def / use.
+ if (RII == RestoreIdxes.end()) {
+ std::vector<SRInfo> Infos;
+ Infos.push_back(SRInfo(index, NewVReg, true));
+ RestoreIdxes.insert(std::make_pair(MBBId, Infos));
+ } else {
+ RII->second.push_back(SRInfo(index, NewVReg, true));
+ }
+ RestoreMBBs.set(MBBId);
+ }
+ }
+
+ // Update spill weight.
+ unsigned loopDepth = loopInfo->getLoopDepth(MBB);
+ nI.weight += getSpillWeight(HasDef, HasUse, loopDepth);
+ }
+
+ if (NewVReg && TrySplit && AllCanFold) {
+ // If all of its def / use can be folded, give it a low spill weight.
+ LiveInterval &nI = getOrCreateInterval(NewVReg);
+ nI.weight /= 10.0F;
+ }
+}
+
+bool LiveIntervals::alsoFoldARestore(int Id, int index, unsigned vr,
+ BitVector &RestoreMBBs,
+ std::map<unsigned,std::vector<SRInfo> > &RestoreIdxes) {
+ if (!RestoreMBBs[Id])
+ return false;
+ std::vector<SRInfo> &Restores = RestoreIdxes[Id];
+ for (unsigned i = 0, e = Restores.size(); i != e; ++i)
+ if (Restores[i].index == index &&
+ Restores[i].vreg == vr &&
+ Restores[i].canFold)
+ return true;
+ return false;
+}
+
+void LiveIntervals::eraseRestoreInfo(int Id, int index, unsigned vr,
+ BitVector &RestoreMBBs,
+ std::map<unsigned,std::vector<SRInfo> > &RestoreIdxes) {
+ if (!RestoreMBBs[Id])
+ return;
+ std::vector<SRInfo> &Restores = RestoreIdxes[Id];
+ for (unsigned i = 0, e = Restores.size(); i != e; ++i)
+ if (Restores[i].index == index && Restores[i].vreg)
+ Restores[i].index = -1;
+}
+
+/// handleSpilledImpDefs - Remove IMPLICIT_DEF instructions which are being
+/// spilled and create empty intervals for their uses.
+void
+LiveIntervals::handleSpilledImpDefs(const LiveInterval &li, VirtRegMap &vrm,
+ const TargetRegisterClass* rc,
+ std::vector<LiveInterval*> &NewLIs) {
+ for (MachineRegisterInfo::reg_iterator ri = mri_->reg_begin(li.reg),
+ re = mri_->reg_end(); ri != re; ) {
+ MachineOperand &O = ri.getOperand();
+ MachineInstr *MI = &*ri;
+ ++ri;
+ if (O.isDef()) {
+ assert(MI->getOpcode() == TargetInstrInfo::IMPLICIT_DEF &&
+ "Register def was not rewritten?");
+ RemoveMachineInstrFromMaps(MI);
+ vrm.RemoveMachineInstrFromMaps(MI);
+ MI->eraseFromParent();
+ } else {
+ // This must be an use of an implicit_def so it's not part of the live
+ // interval. Create a new empty live interval for it.
+ // FIXME: Can we simply erase some of the instructions? e.g. Stores?
+ unsigned NewVReg = mri_->createVirtualRegister(rc);
+ vrm.grow();
+ vrm.setIsImplicitlyDefined(NewVReg);
+ NewLIs.push_back(&getOrCreateInterval(NewVReg));
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = MI->getOperand(i);
+ if (MO.isReg() && MO.getReg() == li.reg)
+ MO.setReg(NewVReg);
+ }
+ }