From 2cb4202f0748ed1e1a40a85dc9cc805629262abf Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Thu, 11 Mar 2010 00:11:33 +0000 Subject: [PATCH] VirtRegRewriter spring cleaning. No functional change. Move methods out of line and M-x whitespace-cleanup. Promote common method arguments to member variables. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98207 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/VirtRegRewriter.cpp | 2547 ++++++++++++++++--------------- 1 file changed, 1292 insertions(+), 1255 deletions(-) diff --git a/lib/CodeGen/VirtRegRewriter.cpp b/lib/CodeGen/VirtRegRewriter.cpp index 7aa0a915352..69a4d20d37f 100644 --- a/lib/CodeGen/VirtRegRewriter.cpp +++ b/lib/CodeGen/VirtRegRewriter.cpp @@ -98,7 +98,7 @@ struct TrivialRewriter : public VirtRegRewriter { bool runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM, LiveIntervals* LIs) { DEBUG(dbgs() << "********** REWRITE MACHINE CODE **********\n"); - DEBUG(dbgs() << "********** Function: " + DEBUG(dbgs() << "********** Function: " << MF.getFunction()->getName() << '\n'); DEBUG(dbgs() << "**** Machine Instrs" << "(NOTE! Does not include spills and reloads!) ****\n"); @@ -135,10 +135,10 @@ struct TrivialRewriter : public VirtRegRewriter { changed |= !reglist.empty(); } } - + DEBUG(dbgs() << "**** Post Machine Instrs ****\n"); DEBUG(MF.dump()); - + return changed; } @@ -208,7 +208,7 @@ public: /// in the specified physreg. If CanClobber is true, the physreg can be /// modified at any time without changing the semantics of the program. void addAvailable(int SlotOrReMat, unsigned Reg, bool CanClobber = true) { - // If this stack slot is thought to be available in some other physreg, + // If this stack slot is thought to be available in some other physreg, // remove its record. ModifyStackSlotOrReMat(SlotOrReMat); @@ -364,7 +364,7 @@ struct ReusedOp { // AssignedPhysReg - The physreg that was assigned for use by the reload. unsigned AssignedPhysReg; - + // VirtReg - The virtual register itself. unsigned VirtReg; @@ -384,11 +384,11 @@ public: ReuseInfo(MachineInstr &mi, const TargetRegisterInfo *tri) : MI(mi) { PhysRegsClobbered.resize(tri->getNumRegs()); } - + bool hasReuses() const { return !Reuses.empty(); } - + /// addReuse - If we choose to reuse a virtual register that is already /// available instead of reloading it, remember that we did so. void addReuse(unsigned OpNo, unsigned StackSlotOrReMat, @@ -397,9 +397,9 @@ public: // If the reload is to the assigned register anyway, no undo will be // required. if (PhysRegReused == AssignedPhysReg) return; - + // Otherwise, remember this. - Reuses.push_back(ReusedOp(OpNo, StackSlotOrReMat, PhysRegReused, + Reuses.push_back(ReusedOp(OpNo, StackSlotOrReMat, PhysRegReused, AssignedPhysReg, VirtReg)); } @@ -410,10 +410,10 @@ public: bool isClobbered(unsigned PhysReg) const { return PhysRegsClobbered.test(PhysReg); } - + /// GetRegForReload - We are about to emit a reload into PhysReg. If there /// is some other operand that is using the specified register, either pick - /// a new register to use, or evict the previous reload and use this reg. + /// a new register to use, or evict the previous reload and use this reg. unsigned GetRegForReload(const TargetRegisterClass *RC, unsigned PhysReg, MachineFunction &MF, MachineInstr *MI, AvailableSpills &Spills, @@ -525,7 +525,7 @@ static void InvalidateKills(MachineInstr &MI, /// reference. static bool InvalidateRegDef(MachineBasicBlock::iterator I, MachineInstr &NewDef, unsigned Reg, - bool &HasLiveDef, + bool &HasLiveDef, const TargetRegisterInfo *TRI) { // Due to remat, it's possible this reg isn't being reused. That is, // the def of this reg (by prev MI) is now dead. @@ -579,7 +579,7 @@ static void UpdateKills(MachineInstr &MI, const TargetRegisterInfo* TRI, unsigned Reg = MO.getReg(); if (Reg == 0) continue; - + if (RegKills[Reg] && KillOps[Reg]->getParent() != &MI) { // That can't be right. Register is killed but not re-defined and it's // being reused. Let's fix that. @@ -597,7 +597,7 @@ static void UpdateKills(MachineInstr &MI, const TargetRegisterInfo* TRI, } } else { // Check for subreg kills as well. - // d4 = + // d4 = // store d4, fi#0 // ... // = s8 @@ -802,7 +802,7 @@ void AvailableSpills::ModifyStackSlotOrReMat(int SlotOrReMat) { if (It == SpillSlotsOrReMatsAvailable.end()) return; unsigned Reg = It->second >> 1; SpillSlotsOrReMatsAvailable.erase(It); - + // This register may hold the value of multiple stack slots, only remove this // stack slot from the set of values the register contains. std::multimap::iterator I = PhysRegsAvailable.lower_bound(Reg); @@ -832,7 +832,7 @@ unsigned ReuseInfo::GetRegForReload(const TargetRegisterClass *RC, VirtRegMap &VRM) { const TargetInstrInfo* TII = MF.getTarget().getInstrInfo(); const TargetRegisterInfo *TRI = Spills.getRegInfo(); - + if (Reuses.empty()) return PhysReg; // This is most often empty. for (unsigned ro = 0, e = Reuses.size(); ro != e; ++ro) { @@ -853,7 +853,7 @@ unsigned ReuseInfo::GetRegForReload(const TargetRegisterClass *RC, } else { // Otherwise, we might also have a problem if a previously reused // value aliases the new register. If so, codegen the previous reload - // and use this one. + // and use this one. unsigned PRRU = Op.PhysRegReused; if (TRI->regsOverlap(PRRU, PhysReg)) { // Okay, we found out that an alias of a reused register @@ -900,13 +900,13 @@ unsigned ReuseInfo::GetRegForReload(const TargetRegisterClass *RC, if (DoReMat) { ReMaterialize(*MBB, InsertLoc, NewPhysReg, NewOp.VirtReg, TII, TRI, VRM); - } else { + } else { TII->loadRegFromStackSlot(*MBB, InsertLoc, NewPhysReg, NewOp.StackSlotOrReMat, AliasRC); MachineInstr *LoadMI = prior(InsertLoc); VRM.addSpillSlotUse(NewOp.StackSlotOrReMat, LoadMI); // Any stores to this stack slot are not dead anymore. - MaybeDeadStores[NewOp.StackSlotOrReMat] = NULL; + MaybeDeadStores[NewOp.StackSlotOrReMat] = NULL; ++NumLoads; } Spills.ClobberPhysReg(NewPhysReg); @@ -919,10 +919,10 @@ unsigned ReuseInfo::GetRegForReload(const TargetRegisterClass *RC, Spills.addAvailable(NewOp.StackSlotOrReMat, NewPhysReg); UpdateKills(*prior(InsertLoc), TRI, RegKills, KillOps); DEBUG(dbgs() << '\t' << *prior(InsertLoc)); - + DEBUG(dbgs() << "Reuse undone!\n"); --NumReused; - + // Finally, PhysReg is now available, go ahead and use it. return PhysReg; } @@ -1037,1410 +1037,1447 @@ void AssignPhysToVirtReg(MachineInstr *MI, unsigned VirtReg, unsigned PhysReg, } namespace { - struct RefSorter { - bool operator()(const std::pair &A, - const std::pair &B) { - return A.second < B.second; - } - }; -} + +struct RefSorter { + bool operator()(const std::pair &A, + const std::pair &B) { + return A.second < B.second; + } +}; // ***************************** // // Local Spiller Implementation // // ***************************** // -namespace { - class LocalRewriter : public VirtRegRewriter { - MachineRegisterInfo *RegInfo; + MachineRegisterInfo *MRI; const TargetRegisterInfo *TRI; const TargetInstrInfo *TII; + VirtRegMap *VRM; BitVector AllocatableRegs; DenseMap DistanceMap; -public: - - bool runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM, - LiveIntervals* LIs) { - RegInfo = &MF.getRegInfo(); - TRI = MF.getTarget().getRegisterInfo(); - TII = MF.getTarget().getInstrInfo(); - AllocatableRegs = TRI->getAllocatableSet(MF); - DEBUG(dbgs() << "\n**** Local spiller rewriting function '" - << MF.getFunction()->getName() << "':\n"); - DEBUG(dbgs() << "**** Machine Instrs (NOTE! Does not include spills and" - " reloads!) ****\n"); - DEBUG(MF.dump()); - - // Spills - Keep track of which spilled values are available in physregs - // so that we can choose to reuse the physregs instead of emitting - // reloads. This is usually refreshed per basic block. - AvailableSpills Spills(TRI, TII); - - // Keep track of kill information. - BitVector RegKills(TRI->getNumRegs()); - std::vector KillOps; - KillOps.resize(TRI->getNumRegs(), NULL); - - // SingleEntrySuccs - Successor blocks which have a single predecessor. - SmallVector SinglePredSuccs; - SmallPtrSet EarlyVisited; - - // Traverse the basic blocks depth first. - MachineBasicBlock *Entry = MF.begin(); - SmallPtrSet Visited; - for (df_ext_iterator > - DFI = df_ext_begin(Entry, Visited), E = df_ext_end(Entry, Visited); - DFI != E; ++DFI) { - MachineBasicBlock *MBB = *DFI; - if (!EarlyVisited.count(MBB)) - RewriteMBB(*MBB, VRM, LIs, Spills, RegKills, KillOps); - - // If this MBB is the only predecessor of a successor. Keep the - // availability information and visit it next. - do { - // Keep visiting single predecessor successor as long as possible. - SinglePredSuccs.clear(); - findSinglePredSuccessor(MBB, SinglePredSuccs); - if (SinglePredSuccs.empty()) - MBB = 0; - else { - // FIXME: More than one successors, each of which has MBB has - // the only predecessor. - MBB = SinglePredSuccs[0]; - if (!Visited.count(MBB) && EarlyVisited.insert(MBB)) { - Spills.AddAvailableRegsToLiveIn(*MBB, RegKills, KillOps); - RewriteMBB(*MBB, VRM, LIs, Spills, RegKills, KillOps); - } - } - } while (MBB); - // Clear the availability info. - Spills.clear(); - } - - DEBUG(dbgs() << "**** Post Machine Instrs ****\n"); - DEBUG(MF.dump()); + MachineBasicBlock *MBB; // Basic block currently being processed. - // Mark unused spill slots. - MachineFrameInfo *MFI = MF.getFrameInfo(); - int SS = VRM.getLowSpillSlot(); - if (SS != VirtRegMap::NO_STACK_SLOT) - for (int e = VRM.getHighSpillSlot(); SS <= e; ++SS) - if (!VRM.isSpillSlotUsed(SS)) { - MFI->RemoveStackObject(SS); - ++NumDSS; - } +public: - return true; - } + bool runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM, + LiveIntervals* LIs); private: - /// OptimizeByUnfold2 - Unfold a series of load / store folding instructions if - /// a scratch register is available. - /// xorq %r12, %r13 - /// addq %rax, -184(%rbp) - /// addq %r13, -184(%rbp) - /// ==> - /// xorq %r12, %r13 - /// movq -184(%rbp), %r12 - /// addq %rax, %r12 - /// addq %r13, %r12 - /// movq %r12, -184(%rbp) bool OptimizeByUnfold2(unsigned VirtReg, int SS, - MachineBasicBlock &MBB, MachineBasicBlock::iterator &MII, std::vector &MaybeDeadStores, AvailableSpills &Spills, BitVector &RegKills, - std::vector &KillOps, - VirtRegMap &VRM) { + std::vector &KillOps); - MachineBasicBlock::iterator NextMII = llvm::next(MII); - if (NextMII == MBB.end()) - return false; + bool OptimizeByUnfold(MachineBasicBlock::iterator &MII, + std::vector &MaybeDeadStores, + AvailableSpills &Spills, + BitVector &RegKills, + std::vector &KillOps); - if (TII->getOpcodeAfterMemoryUnfold(MII->getOpcode(), true, true) == 0) - return false; + bool CommuteToFoldReload(MachineBasicBlock::iterator &MII, + unsigned VirtReg, unsigned SrcReg, int SS, + AvailableSpills &Spills, + BitVector &RegKills, + std::vector &KillOps, + const TargetRegisterInfo *TRI); - // Now let's see if the last couple of instructions happens to have freed up - // a register. - const TargetRegisterClass* RC = RegInfo->getRegClass(VirtReg); - unsigned PhysReg = FindFreeRegister(MII, MBB, RC, TRI, AllocatableRegs); - if (!PhysReg) - return false; + void SpillRegToStackSlot(MachineBasicBlock::iterator &MII, + int Idx, unsigned PhysReg, int StackSlot, + const TargetRegisterClass *RC, + bool isAvailable, MachineInstr *&LastStore, + AvailableSpills &Spills, + SmallSet &ReMatDefs, + BitVector &RegKills, + std::vector &KillOps); - MachineFunction &MF = *MBB.getParent(); - TRI = MF.getTarget().getRegisterInfo(); - MachineInstr &MI = *MII; - if (!FoldsStackSlotModRef(MI, SS, PhysReg, TII, TRI, VRM)) - return false; + void TransferDeadness(unsigned CurDist, + unsigned Reg, BitVector &RegKills, + std::vector &KillOps); - // If the next instruction also folds the same SS modref and can be unfoled, - // then it's worthwhile to issue a load from SS into the free register and - // then unfold these instructions. - if (!FoldsStackSlotModRef(*NextMII, SS, PhysReg, TII, TRI, VRM)) - return false; + void RewriteMBB(LiveIntervals *LIs, + AvailableSpills &Spills, BitVector &RegKills, + std::vector &KillOps); +}; +} - // Back-schedule reloads and remats. - ComputeReloadLoc(MII, MBB.begin(), PhysReg, TRI, false, SS, TII, MF); +bool LocalRewriter::runOnMachineFunction(MachineFunction &MF, VirtRegMap &vrm, + LiveIntervals* LIs) { + MRI = &MF.getRegInfo(); + TRI = MF.getTarget().getRegisterInfo(); + TII = MF.getTarget().getInstrInfo(); + VRM = &vrm; + AllocatableRegs = TRI->getAllocatableSet(MF); + DEBUG(dbgs() << "\n**** Local spiller rewriting function '" + << MF.getFunction()->getName() << "':\n"); + DEBUG(dbgs() << "**** Machine Instrs (NOTE! Does not include spills and" + " reloads!) ****\n"); + DEBUG(MF.dump()); + + // Spills - Keep track of which spilled values are available in physregs + // so that we can choose to reuse the physregs instead of emitting + // reloads. This is usually refreshed per basic block. + AvailableSpills Spills(TRI, TII); + + // Keep track of kill information. + BitVector RegKills(TRI->getNumRegs()); + std::vector KillOps; + KillOps.resize(TRI->getNumRegs(), NULL); + + // SingleEntrySuccs - Successor blocks which have a single predecessor. + SmallVector SinglePredSuccs; + SmallPtrSet EarlyVisited; + + // Traverse the basic blocks depth first. + MachineBasicBlock *Entry = MF.begin(); + SmallPtrSet Visited; + for (df_ext_iterator > + DFI = df_ext_begin(Entry, Visited), E = df_ext_end(Entry, Visited); + DFI != E; ++DFI) { + MBB = *DFI; + if (!EarlyVisited.count(MBB)) + RewriteMBB(LIs, Spills, RegKills, KillOps); + + // If this MBB is the only predecessor of a successor. Keep the + // availability information and visit it next. + do { + // Keep visiting single predecessor successor as long as possible. + SinglePredSuccs.clear(); + findSinglePredSuccessor(MBB, SinglePredSuccs); + if (SinglePredSuccs.empty()) + MBB = 0; + else { + // FIXME: More than one successors, each of which has MBB has + // the only predecessor. + MBB = SinglePredSuccs[0]; + if (!Visited.count(MBB) && EarlyVisited.insert(MBB)) { + Spills.AddAvailableRegsToLiveIn(*MBB, RegKills, KillOps); + RewriteMBB(LIs, Spills, RegKills, KillOps); + } + } + } while (MBB); - // Load from SS to the spare physical register. - TII->loadRegFromStackSlot(MBB, MII, PhysReg, SS, RC); - // This invalidates Phys. - Spills.ClobberPhysReg(PhysReg); - // Remember it's available. - Spills.addAvailable(SS, PhysReg); - MaybeDeadStores[SS] = NULL; + // Clear the availability info. + Spills.clear(); + } - // Unfold current MI. - SmallVector NewMIs; - if (!TII->unfoldMemoryOperand(MF, &MI, VirtReg, false, false, NewMIs)) + DEBUG(dbgs() << "**** Post Machine Instrs ****\n"); + DEBUG(MF.dump()); + + // Mark unused spill slots. + MachineFrameInfo *MFI = MF.getFrameInfo(); + int SS = VRM->getLowSpillSlot(); + if (SS != VirtRegMap::NO_STACK_SLOT) + for (int e = VRM->getHighSpillSlot(); SS <= e; ++SS) + if (!VRM->isSpillSlotUsed(SS)) { + MFI->RemoveStackObject(SS); + ++NumDSS; + } + + return true; +} + +/// OptimizeByUnfold2 - Unfold a series of load / store folding instructions if +/// a scratch register is available. +/// xorq %r12, %r13 +/// addq %rax, -184(%rbp) +/// addq %r13, -184(%rbp) +/// ==> +/// xorq %r12, %r13 +/// movq -184(%rbp), %r12 +/// addq %rax, %r12 +/// addq %r13, %r12 +/// movq %r12, -184(%rbp) +bool LocalRewriter:: +OptimizeByUnfold2(unsigned VirtReg, int SS, + MachineBasicBlock::iterator &MII, + std::vector &MaybeDeadStores, + AvailableSpills &Spills, + BitVector &RegKills, + std::vector &KillOps) { + + MachineBasicBlock::iterator NextMII = llvm::next(MII); + if (NextMII == MBB->end()) + return false; + + if (TII->getOpcodeAfterMemoryUnfold(MII->getOpcode(), true, true) == 0) + return false; + + // Now let's see if the last couple of instructions happens to have freed up + // a register. + const TargetRegisterClass* RC = MRI->getRegClass(VirtReg); + unsigned PhysReg = FindFreeRegister(MII, *MBB, RC, TRI, AllocatableRegs); + if (!PhysReg) + return false; + + MachineFunction &MF = *MBB->getParent(); + TRI = MF.getTarget().getRegisterInfo(); + MachineInstr &MI = *MII; + if (!FoldsStackSlotModRef(MI, SS, PhysReg, TII, TRI, *VRM)) + return false; + + // If the next instruction also folds the same SS modref and can be unfoled, + // then it's worthwhile to issue a load from SS into the free register and + // then unfold these instructions. + if (!FoldsStackSlotModRef(*NextMII, SS, PhysReg, TII, TRI, *VRM)) + return false; + + // Back-schedule reloads and remats. + ComputeReloadLoc(MII, MBB->begin(), PhysReg, TRI, false, SS, TII, MF); + + // Load from SS to the spare physical register. + TII->loadRegFromStackSlot(*MBB, MII, PhysReg, SS, RC); + // This invalidates Phys. + Spills.ClobberPhysReg(PhysReg); + // Remember it's available. + Spills.addAvailable(SS, PhysReg); + MaybeDeadStores[SS] = NULL; + + // Unfold current MI. + SmallVector NewMIs; + if (!TII->unfoldMemoryOperand(MF, &MI, VirtReg, false, false, NewMIs)) + llvm_unreachable("Unable unfold the load / store folding instruction!"); + assert(NewMIs.size() == 1); + AssignPhysToVirtReg(NewMIs[0], VirtReg, PhysReg, *TRI); + VRM->transferRestorePts(&MI, NewMIs[0]); + MII = MBB->insert(MII, NewMIs[0]); + InvalidateKills(MI, TRI, RegKills, KillOps); + VRM->RemoveMachineInstrFromMaps(&MI); + MBB->erase(&MI); + ++NumModRefUnfold; + + // Unfold next instructions that fold the same SS. + do { + MachineInstr &NextMI = *NextMII; + NextMII = llvm::next(NextMII); + NewMIs.clear(); + if (!TII->unfoldMemoryOperand(MF, &NextMI, VirtReg, false, false, NewMIs)) llvm_unreachable("Unable unfold the load / store folding instruction!"); assert(NewMIs.size() == 1); AssignPhysToVirtReg(NewMIs[0], VirtReg, PhysReg, *TRI); - VRM.transferRestorePts(&MI, NewMIs[0]); - MII = MBB.insert(MII, NewMIs[0]); - InvalidateKills(MI, TRI, RegKills, KillOps); - VRM.RemoveMachineInstrFromMaps(&MI); - MBB.erase(&MI); + VRM->transferRestorePts(&NextMI, NewMIs[0]); + MBB->insert(NextMII, NewMIs[0]); + InvalidateKills(NextMI, TRI, RegKills, KillOps); + VRM->RemoveMachineInstrFromMaps(&NextMI); + MBB->erase(&NextMI); ++NumModRefUnfold; + if (NextMII == MBB->end()) + break; + } while (FoldsStackSlotModRef(*NextMII, SS, PhysReg, TII, TRI, *VRM)); - // Unfold next instructions that fold the same SS. - do { - MachineInstr &NextMI = *NextMII; - NextMII = llvm::next(NextMII); - NewMIs.clear(); - if (!TII->unfoldMemoryOperand(MF, &NextMI, VirtReg, false, false, NewMIs)) - llvm_unreachable("Unable unfold the load / store folding instruction!"); - assert(NewMIs.size() == 1); - AssignPhysToVirtReg(NewMIs[0], VirtReg, PhysReg, *TRI); - VRM.transferRestorePts(&NextMI, NewMIs[0]); - MBB.insert(NextMII, NewMIs[0]); - InvalidateKills(NextMI, TRI, RegKills, KillOps); - VRM.RemoveMachineInstrFromMaps(&NextMI); - MBB.erase(&NextMI); - ++NumModRefUnfold; - if (NextMII == MBB.end()) - break; - } while (FoldsStackSlotModRef(*NextMII, SS, PhysReg, TII, TRI, VRM)); - - // Store the value back into SS. - TII->storeRegToStackSlot(MBB, NextMII, PhysReg, true, SS, RC); - MachineInstr *StoreMI = prior(NextMII); - VRM.addSpillSlotUse(SS, StoreMI); - VRM.virtFolded(VirtReg, StoreMI, VirtRegMap::isMod); + // Store the value back into SS. + TII->storeRegToStackSlot(*MBB, NextMII, PhysReg, true, SS, RC); + MachineInstr *StoreMI = prior(NextMII); + VRM->addSpillSlotUse(SS, StoreMI); + VRM->virtFolded(VirtReg, StoreMI, VirtRegMap::isMod); - return true; - } + return true; +} - /// OptimizeByUnfold - Turn a store folding instruction into a load folding - /// instruction. e.g. - /// xorl %edi, %eax - /// movl %eax, -32(%ebp) - /// movl -36(%ebp), %eax - /// orl %eax, -32(%ebp) - /// ==> - /// xorl %edi, %eax - /// orl -36(%ebp), %eax - /// mov %eax, -32(%ebp) - /// This enables unfolding optimization for a subsequent instruction which will - /// also eliminate the newly introduced store instruction. - bool OptimizeByUnfold(MachineBasicBlock &MBB, - MachineBasicBlock::iterator &MII, - std::vector &MaybeDeadStores, - AvailableSpills &Spills, - BitVector &RegKills, - std::vector &KillOps, - VirtRegMap &VRM) { - MachineFunction &MF = *MBB.getParent(); - MachineInstr &MI = *MII; - unsigned UnfoldedOpc = 0; - unsigned UnfoldPR = 0; - unsigned UnfoldVR = 0; - int FoldedSS = VirtRegMap::NO_STACK_SLOT; - VirtRegMap::MI2VirtMapTy::const_iterator I, End; - for (tie(I, End) = VRM.getFoldedVirts(&MI); I != End; ) { - // Only transform a MI that folds a single register. - if (UnfoldedOpc) - return false; - UnfoldVR = I->second.first; - VirtRegMap::ModRef MR = I->second.second; - // MI2VirtMap be can updated which invalidate the iterator. - // Increment the iterator first. - ++I; - if (VRM.isAssignedReg(UnfoldVR)) +/// OptimizeByUnfold - Turn a store folding instruction into a load folding +/// instruction. e.g. +/// xorl %edi, %eax +/// movl %eax, -32(%ebp) +/// movl -36(%ebp), %eax +/// orl %eax, -32(%ebp) +/// ==> +/// xorl %edi, %eax +/// orl -36(%ebp), %eax +/// mov %eax, -32(%ebp) +/// This enables unfolding optimization for a subsequent instruction which will +/// also eliminate the newly introduced store instruction. +bool LocalRewriter:: +OptimizeByUnfold(MachineBasicBlock::iterator &MII, + std::vector &MaybeDeadStores, + AvailableSpills &Spills, + BitVector &RegKills, + std::vector &KillOps) { + MachineFunction &MF = *MBB->getParent(); + MachineInstr &MI = *MII; + unsigned UnfoldedOpc = 0; + unsigned UnfoldPR = 0; + unsigned UnfoldVR = 0; + int FoldedSS = VirtRegMap::NO_STACK_SLOT; + VirtRegMap::MI2VirtMapTy::const_iterator I, End; + for (tie(I, End) = VRM->getFoldedVirts(&MI); I != End; ) { + // Only transform a MI that folds a single register. + if (UnfoldedOpc) + return false; + UnfoldVR = I->second.first; + VirtRegMap::ModRef MR = I->second.second; + // MI2VirtMap be can updated which invalidate the iterator. + // Increment the iterator first. + ++I; + if (VRM->isAssignedReg(UnfoldVR)) + continue; + // If this reference is not a use, any previous store is now dead. + // Otherwise, the store to this stack slot is not dead anymore. + FoldedSS = VRM->getStackSlot(UnfoldVR); + MachineInstr* DeadStore = MaybeDeadStores[FoldedSS]; + if (DeadStore && (MR & VirtRegMap::isModRef)) { + unsigned PhysReg = Spills.getSpillSlotOrReMatPhysReg(FoldedSS); + if (!PhysReg || !DeadStore->readsRegister(PhysReg)) continue; - // If this reference is not a use, any previous store is now dead. - // Otherwise, the store to this stack slot is not dead anymore. - FoldedSS = VRM.getStackSlot(UnfoldVR); - MachineInstr* DeadStore = MaybeDeadStores[FoldedSS]; - if (DeadStore && (MR & VirtRegMap::isModRef)) { - unsigned PhysReg = Spills.getSpillSlotOrReMatPhysReg(FoldedSS); - if (!PhysReg || !DeadStore->readsRegister(PhysReg)) - continue; - UnfoldPR = PhysReg; - UnfoldedOpc = TII->getOpcodeAfterMemoryUnfold(MI.getOpcode(), - false, true); - } + UnfoldPR = PhysReg; + UnfoldedOpc = TII->getOpcodeAfterMemoryUnfold(MI.getOpcode(), + false, true); } + } - if (!UnfoldedOpc) { - if (!UnfoldVR) - return false; + if (!UnfoldedOpc) { + if (!UnfoldVR) + return false; - // Look for other unfolding opportunities. - return OptimizeByUnfold2(UnfoldVR, FoldedSS, MBB, MII, - MaybeDeadStores, Spills, RegKills, KillOps, VRM); - } + // Look for other unfolding opportunities. + return OptimizeByUnfold2(UnfoldVR, FoldedSS, MII, MaybeDeadStores, Spills, + RegKills, KillOps); + } - for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { - MachineOperand &MO = MI.getOperand(i); - if (!MO.isReg() || MO.getReg() == 0 || !MO.isUse()) - continue; - unsigned VirtReg = MO.getReg(); - if (TargetRegisterInfo::isPhysicalRegister(VirtReg) || MO.getSubReg()) - continue; - if (VRM.isAssignedReg(VirtReg)) { - unsigned PhysReg = VRM.getPhys(VirtReg); - if (PhysReg && TRI->regsOverlap(PhysReg, UnfoldPR)) - return false; - } else if (VRM.isReMaterialized(VirtReg)) - continue; - int SS = VRM.getStackSlot(VirtReg); - unsigned PhysReg = Spills.getSpillSlotOrReMatPhysReg(SS); - if (PhysReg) { - if (TRI->regsOverlap(PhysReg, UnfoldPR)) - return false; + for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { + MachineOperand &MO = MI.getOperand(i); + if (!MO.isReg() || MO.getReg() == 0 || !MO.isUse()) + continue; + unsigned VirtReg = MO.getReg(); + if (TargetRegisterInfo::isPhysicalRegister(VirtReg) || MO.getSubReg()) + continue; + if (VRM->isAssignedReg(VirtReg)) { + unsigned PhysReg = VRM->getPhys(VirtReg); + if (PhysReg && TRI->regsOverlap(PhysReg, UnfoldPR)) + return false; + } else if (VRM->isReMaterialized(VirtReg)) + continue; + int SS = VRM->getStackSlot(VirtReg); + unsigned PhysReg = Spills.getSpillSlotOrReMatPhysReg(SS); + if (PhysReg) { + if (TRI->regsOverlap(PhysReg, UnfoldPR)) + return false; + continue; + } + if (VRM->hasPhys(VirtReg)) { + PhysReg = VRM->getPhys(VirtReg); + if (!TRI->regsOverlap(PhysReg, UnfoldPR)) continue; - } - if (VRM.hasPhys(VirtReg)) { - PhysReg = VRM.getPhys(VirtReg); - if (!TRI->regsOverlap(PhysReg, UnfoldPR)) - continue; - } + } - // Ok, we'll need to reload the value into a register which makes - // it impossible to perform the store unfolding optimization later. - // Let's see if it is possible to fold the load if the store is - // unfolded. This allows us to perform the store unfolding - // optimization. - SmallVector NewMIs; - if (TII->unfoldMemoryOperand(MF, &MI, UnfoldVR, false, false, NewMIs)) { - assert(NewMIs.size() == 1); - MachineInstr *NewMI = NewMIs.back(); - NewMIs.clear(); - int Idx = NewMI->findRegisterUseOperandIdx(VirtReg, false); - assert(Idx != -1); - SmallVector Ops; - Ops.push_back(Idx); - MachineInstr *FoldedMI = TII->foldMemoryOperand(MF, NewMI, Ops, SS); - if (FoldedMI) { - VRM.addSpillSlotUse(SS, FoldedMI); - if (!VRM.hasPhys(UnfoldVR)) - VRM.assignVirt2Phys(UnfoldVR, UnfoldPR); - VRM.virtFolded(VirtReg, FoldedMI, VirtRegMap::isRef); - MII = MBB.insert(MII, FoldedMI); - InvalidateKills(MI, TRI, RegKills, KillOps); - VRM.RemoveMachineInstrFromMaps(&MI); - MBB.erase(&MI); - MF.DeleteMachineInstr(NewMI); - return true; - } + // Ok, we'll need to reload the value into a register which makes + // it impossible to perform the store unfolding optimization later. + // Let's see if it is possible to fold the load if the store is + // unfolded. This allows us to perform the store unfolding + // optimization. + SmallVector NewMIs; + if (TII->unfoldMemoryOperand(MF, &MI, UnfoldVR, false, false, NewMIs)) { + assert(NewMIs.size() == 1); + MachineInstr *NewMI = NewMIs.back(); + NewMIs.clear(); + int Idx = NewMI->findRegisterUseOperandIdx(VirtReg, false); + assert(Idx != -1); + SmallVector Ops; + Ops.push_back(Idx); + MachineInstr *FoldedMI = TII->foldMemoryOperand(MF, NewMI, Ops, SS); + if (FoldedMI) { + VRM->addSpillSlotUse(SS, FoldedMI); + if (!VRM->hasPhys(UnfoldVR)) + VRM->assignVirt2Phys(UnfoldVR, UnfoldPR); + VRM->virtFolded(VirtReg, FoldedMI, VirtRegMap::isRef); + MII = MBB->insert(MII, FoldedMI); + InvalidateKills(MI, TRI, RegKills, KillOps); + VRM->RemoveMachineInstrFromMaps(&MI); + MBB->erase(&MI); MF.DeleteMachineInstr(NewMI); + return true; } + MF.DeleteMachineInstr(NewMI); } + } + return false; +} + +/// CommuteChangesDestination - We are looking for r0 = op r1, r2 and +/// where SrcReg is r1 and it is tied to r0. Return true if after +/// commuting this instruction it will be r0 = op r2, r1. +static bool CommuteChangesDestination(MachineInstr *DefMI, + const TargetInstrDesc &TID, + unsigned SrcReg, + const TargetInstrInfo *TII, + unsigned &DstIdx) { + if (TID.getNumDefs() != 1 && TID.getNumOperands() != 3) + return false; + if (!DefMI->getOperand(1).isReg() || + DefMI->getOperand(1).getReg() != SrcReg) return false; + unsigned DefIdx; + if (!DefMI->isRegTiedToDefOperand(1, &DefIdx) || DefIdx != 0) + return false; + unsigned SrcIdx1, SrcIdx2; + if (!TII->findCommutedOpIndices(DefMI, SrcIdx1, SrcIdx2)) + return false; + if (SrcIdx1 == 1 && SrcIdx2 == 2) { + DstIdx = 2; + return true; } + return false; +} - /// CommuteChangesDestination - We are looking for r0 = op r1, r2 and - /// where SrcReg is r1 and it is tied to r0. Return true if after - /// commuting this instruction it will be r0 = op r2, r1. - static bool CommuteChangesDestination(MachineInstr *DefMI, - const TargetInstrDesc &TID, - unsigned SrcReg, - const TargetInstrInfo *TII, - unsigned &DstIdx) { - if (TID.getNumDefs() != 1 && TID.getNumOperands() != 3) +/// CommuteToFoldReload - +/// Look for +/// r1 = load fi#1 +/// r1 = op r1, r2 +/// store r1, fi#1 +/// +/// If op is commutable and r2 is killed, then we can xform these to +/// r2 = op r2, fi#1 +/// store r2, fi#1 +bool LocalRewriter:: +CommuteToFoldReload(MachineBasicBlock::iterator &MII, + unsigned VirtReg, unsigned SrcReg, int SS, + AvailableSpills &Spills, + BitVector &RegKills, + std::vector &KillOps, + const TargetRegisterInfo *TRI) { + if (MII == MBB->begin() || !MII->killsRegister(SrcReg)) + return false; + + MachineFunction &MF = *MBB->getParent(); + MachineInstr &MI = *MII; + MachineBasicBlock::iterator DefMII = prior(MII); + MachineInstr *DefMI = DefMII; + const TargetInstrDesc &TID = DefMI->getDesc(); + unsigned NewDstIdx; + if (DefMII != MBB->begin() && + TID.isCommutable() && + CommuteChangesDestination(DefMI, TID, SrcReg, TII, NewDstIdx)) { + MachineOperand &NewDstMO = DefMI->getOperand(NewDstIdx); + unsigned NewReg = NewDstMO.getReg(); + if (!NewDstMO.isKill() || TRI->regsOverlap(NewReg, SrcReg)) return false; - if (!DefMI->getOperand(1).isReg() || - DefMI->getOperand(1).getReg() != SrcReg) + MachineInstr *ReloadMI = prior(DefMII); + int FrameIdx; + unsigned DestReg = TII->isLoadFromStackSlot(ReloadMI, FrameIdx); + if (DestReg != SrcReg || FrameIdx != SS) return false; - unsigned DefIdx; - if (!DefMI->isRegTiedToDefOperand(1, &DefIdx) || DefIdx != 0) + int UseIdx = DefMI->findRegisterUseOperandIdx(DestReg, false); + if (UseIdx == -1) return false; - unsigned SrcIdx1, SrcIdx2; - if (!TII->findCommutedOpIndices(DefMI, SrcIdx1, SrcIdx2)) + unsigned DefIdx; + if (!MI.isRegTiedToDefOperand(UseIdx, &DefIdx)) return false; - if (SrcIdx1 == 1 && SrcIdx2 == 2) { - DstIdx = 2; - return true; - } - return false; - } + assert(DefMI->getOperand(DefIdx).isReg() && + DefMI->getOperand(DefIdx).getReg() == SrcReg); - /// CommuteToFoldReload - - /// Look for - /// r1 = load fi#1 - /// r1 = op r1, r2 - /// store r1, fi#1 - /// - /// If op is commutable and r2 is killed, then we can xform these to - /// r2 = op r2, fi#1 - /// store r2, fi#1 - bool CommuteToFoldReload(MachineBasicBlock &MBB, - MachineBasicBlock::iterator &MII, - unsigned VirtReg, unsigned SrcReg, int SS, - AvailableSpills &Spills, - BitVector &RegKills, - std::vector &KillOps, - const TargetRegisterInfo *TRI, - VirtRegMap &VRM) { - if (MII == MBB.begin() || !MII->killsRegister(SrcReg)) + // Now commute def instruction. + MachineInstr *CommutedMI = TII->commuteInstruction(DefMI, true); + if (!CommutedMI) + return false; + SmallVector Ops; + Ops.push_back(NewDstIdx); + MachineInstr *FoldedMI = TII->foldMemoryOperand(MF, CommutedMI, Ops, SS); + // Not needed since foldMemoryOperand returns new MI. + MF.DeleteMachineInstr(CommutedMI); + if (!FoldedMI) return false; - MachineFunction &MF = *MBB.getParent(); - MachineInstr &MI = *MII; - MachineBasicBlock::iterator DefMII = prior(MII); - MachineInstr *DefMI = DefMII; - const TargetInstrDesc &TID = DefMI->getDesc(); - unsigned NewDstIdx; - if (DefMII != MBB.begin() && - TID.isCommutable() && - CommuteChangesDestination(DefMI, TID, SrcReg, TII, NewDstIdx)) { - MachineOperand &NewDstMO = DefMI->getOperand(NewDstIdx); - unsigned NewReg = NewDstMO.getReg(); - if (!NewDstMO.isKill() || TRI->regsOverlap(NewReg, SrcReg)) - return false; - MachineInstr *ReloadMI = prior(DefMII); - int FrameIdx; - unsigned DestReg = TII->isLoadFromStackSlot(ReloadMI, FrameIdx); - if (DestReg != SrcReg || FrameIdx != SS) - return false; - int UseIdx = DefMI->findRegisterUseOperandIdx(DestReg, false); - if (UseIdx == -1) - return false; - unsigned DefIdx; - if (!MI.isRegTiedToDefOperand(UseIdx, &DefIdx)) - return false; - assert(DefMI->getOperand(DefIdx).isReg() && - DefMI->getOperand(DefIdx).getReg() == SrcReg); - - // Now commute def instruction. - MachineInstr *CommutedMI = TII->commuteInstruction(DefMI, true); - if (!CommutedMI) - return false; - SmallVector Ops; - Ops.push_back(NewDstIdx); - MachineInstr *FoldedMI = TII->foldMemoryOperand(MF, CommutedMI, Ops, SS); - // Not needed since foldMemoryOperand returns new MI. - MF.DeleteMachineInstr(CommutedMI); - if (!FoldedMI) - return false; - - VRM.addSpillSlotUse(SS, FoldedMI); - VRM.virtFolded(VirtReg, FoldedMI, VirtRegMap::isRef); - // Insert new def MI and spill MI. - const TargetRegisterClass* RC = RegInfo->getRegClass(VirtReg); - TII->storeRegToStackSlot(MBB, &MI, NewReg, true, SS, RC); - MII = prior(MII); - MachineInstr *StoreMI = MII; - VRM.addSpillSlotUse(SS, StoreMI); - VRM.virtFolded(VirtReg, StoreMI, VirtRegMap::isMod); - MII = MBB.insert(MII, FoldedMI); // Update MII to backtrack. - - // Delete all 3 old instructions. - InvalidateKills(*ReloadMI, TRI, RegKills, KillOps); - VRM.RemoveMachineInstrFromMaps(ReloadMI); - MBB.erase(ReloadMI); - InvalidateKills(*DefMI, TRI, RegKills, KillOps); - VRM.RemoveMachineInstrFromMaps(DefMI); - MBB.erase(DefMI); - InvalidateKills(MI, TRI, RegKills, KillOps); - VRM.RemoveMachineInstrFromMaps(&MI); - MBB.erase(&MI); - - // If NewReg was previously holding value of some SS, it's now clobbered. - // This has to be done now because it's a physical register. When this - // instruction is re-visited, it's ignored. - Spills.ClobberPhysReg(NewReg); + VRM->addSpillSlotUse(SS, FoldedMI); + VRM->virtFolded(VirtReg, FoldedMI, VirtRegMap::isRef); + // Insert new def MI and spill MI. + const TargetRegisterClass* RC = MRI->getRegClass(VirtReg); + TII->storeRegToStackSlot(*MBB, &MI, NewReg, true, SS, RC); + MII = prior(MII); + MachineInstr *StoreMI = MII; + VRM->addSpillSlotUse(SS, StoreMI); + VRM->virtFolded(VirtReg, StoreMI, VirtRegMap::isMod); + MII = MBB->insert(MII, FoldedMI); // Update MII to backtrack. + + // Delete all 3 old instructions. + InvalidateKills(*ReloadMI, TRI, RegKills, KillOps); + VRM->RemoveMachineInstrFromMaps(ReloadMI); + MBB->erase(ReloadMI); + InvalidateKills(*DefMI, TRI, RegKills, KillOps); + VRM->RemoveMachineInstrFromMaps(DefMI); + MBB->erase(DefMI); + InvalidateKills(MI, TRI, RegKills, KillOps); + VRM->RemoveMachineInstrFromMaps(&MI); + MBB->erase(&MI); - ++NumCommutes; - return true; - } + // If NewReg was previously holding value of some SS, it's now clobbered. + // This has to be done now because it's a physical register. When this + // instruction is re-visited, it's ignored. + Spills.ClobberPhysReg(NewReg); - return false; + ++NumCommutes; + return true; } - /// SpillRegToStackSlot - Spill a register to a specified stack slot. Check if - /// the last store to the same slot is now dead. If so, remove the last store. - void SpillRegToStackSlot(MachineBasicBlock &MBB, - MachineBasicBlock::iterator &MII, - int Idx, unsigned PhysReg, int StackSlot, - const TargetRegisterClass *RC, - bool isAvailable, MachineInstr *&LastStore, - AvailableSpills &Spills, - SmallSet &ReMatDefs, - BitVector &RegKills, - std::vector &KillOps, - VirtRegMap &VRM) { + return false; +} - MachineBasicBlock::iterator oldNextMII = llvm::next(MII); - TII->storeRegToStackSlot(MBB, llvm::next(MII), PhysReg, true, StackSlot, RC); - MachineInstr *StoreMI = prior(oldNextMII); - VRM.addSpillSlotUse(StackSlot, StoreMI); - DEBUG(dbgs() << "Store:\t" << *StoreMI); - - // If there is a dead store to this stack slot, nuke it now. - if (LastStore) { - DEBUG(dbgs() << "Removed dead store:\t" << *LastStore); - ++NumDSE; - SmallVector KillRegs; - InvalidateKills(*LastStore, TRI, RegKills, KillOps, &KillRegs); - MachineBasicBlock::iterator PrevMII = LastStore; - bool CheckDef = PrevMII != MBB.begin(); - if (CheckDef) - --PrevMII; - VRM.RemoveMachineInstrFromMaps(LastStore); - MBB.erase(LastStore); - if (CheckDef) { - // Look at defs of killed registers on the store. Mark the defs - // as dead since the store has been deleted and they aren't - // being reused. - for (unsigned j = 0, ee = KillRegs.size(); j != ee; ++j) { - bool HasOtherDef = false; - if (InvalidateRegDef(PrevMII, *MII, KillRegs[j], HasOtherDef, TRI)) { - MachineInstr *DeadDef = PrevMII; - if (ReMatDefs.count(DeadDef) && !HasOtherDef) { - // FIXME: This assumes a remat def does not have side effects. - VRM.RemoveMachineInstrFromMaps(DeadDef); - MBB.erase(DeadDef); - ++NumDRM; - } +/// SpillRegToStackSlot - Spill a register to a specified stack slot. Check if +/// the last store to the same slot is now dead. If so, remove the last store. +void LocalRewriter:: +SpillRegToStackSlot(MachineBasicBlock::iterator &MII, + int Idx, unsigned PhysReg, int StackSlot, + const TargetRegisterClass *RC, + bool isAvailable, MachineInstr *&LastStore, + AvailableSpills &Spills, + SmallSet &ReMatDefs, + BitVector &RegKills, + std::vector &KillOps) { + + MachineBasicBlock::iterator oldNextMII = llvm::next(MII); + TII->storeRegToStackSlot(*MBB, llvm::next(MII), PhysReg, true, StackSlot, RC); + MachineInstr *StoreMI = prior(oldNextMII); + VRM->addSpillSlotUse(StackSlot, StoreMI); + DEBUG(dbgs() << "Store:\t" << *StoreMI); + + // If there is a dead store to this stack slot, nuke it now. + if (LastStore) { + DEBUG(dbgs() << "Removed dead store:\t" << *LastStore); + ++NumDSE; + SmallVector KillRegs; + InvalidateKills(*LastStore, TRI, RegKills, KillOps, &KillRegs); + MachineBasicBlock::iterator PrevMII = LastStore; + bool CheckDef = PrevMII != MBB->begin(); + if (CheckDef) + --PrevMII; + VRM->RemoveMachineInstrFromMaps(LastStore); + MBB->erase(LastStore); + if (CheckDef) { + // Look at defs of killed registers on the store. Mark the defs + // as dead since the store has been deleted and they aren't + // being reused. + for (unsigned j = 0, ee = KillRegs.size(); j != ee; ++j) { + bool HasOtherDef = false; + if (InvalidateRegDef(PrevMII, *MII, KillRegs[j], HasOtherDef, TRI)) { + MachineInstr *DeadDef = PrevMII; + if (ReMatDefs.count(DeadDef) && !HasOtherDef) { + // FIXME: This assumes a remat def does not have side effects. + VRM->RemoveMachineInstrFromMaps(DeadDef); + MBB->erase(DeadDef); + ++NumDRM; } } } } - - // Allow for multi-instruction spill sequences, as on PPC Altivec. Presume - // the last of multiple instructions is the actual store. - LastStore = prior(oldNextMII); - - // If the stack slot value was previously available in some other - // register, change it now. Otherwise, make the register available, - // in PhysReg. - Spills.ModifyStackSlotOrReMat(StackSlot); - Spills.ClobberPhysReg(PhysReg); - Spills.addAvailable(StackSlot, PhysReg, isAvailable); - ++NumStores; } - /// isSafeToDelete - Return true if this instruction doesn't produce any side - /// effect and all of its defs are dead. - static bool isSafeToDelete(MachineInstr &MI) { - const TargetInstrDesc &TID = MI.getDesc(); - if (TID.mayLoad() || TID.mayStore() || TID.isCall() || TID.isTerminator() || - TID.isCall() || TID.isBarrier() || TID.isReturn() || - TID.hasUnmodeledSideEffects()) + // Allow for multi-instruction spill sequences, as on PPC Altivec. Presume + // the last of multiple instructions is the actual store. + LastStore = prior(oldNextMII); + + // If the stack slot value was previously available in some other + // register, change it now. Otherwise, make the register available, + // in PhysReg. + Spills.ModifyStackSlotOrReMat(StackSlot); + Spills.ClobberPhysReg(PhysReg); + Spills.addAvailable(StackSlot, PhysReg, isAvailable); + ++NumStores; +} + +/// isSafeToDelete - Return true if this instruction doesn't produce any side +/// effect and all of its defs are dead. +static bool isSafeToDelete(MachineInstr &MI) { + const TargetInstrDesc &TID = MI.getDesc(); + if (TID.mayLoad() || TID.mayStore() || TID.isCall() || TID.isTerminator() || + TID.isCall() || TID.isBarrier() || TID.isReturn() || + TID.hasUnmodeledSideEffects()) + return false; + for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { + MachineOperand &MO = MI.getOperand(i); + if (!MO.isReg() || !MO.getReg()) + continue; + if (MO.isDef() && !MO.isDead()) + return false; + if (MO.isUse() && MO.isKill()) + // FIXME: We can't remove kill markers or else the scavenger will assert. + // An alternative is to add a ADD pseudo instruction to replace kill + // markers. return false; - for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { - MachineOperand &MO = MI.getOperand(i); - if (!MO.isReg() || !MO.getReg()) - continue; - if (MO.isDef() && !MO.isDead()) - return false; - if (MO.isUse() && MO.isKill()) - // FIXME: We can't remove kill markers or else the scavenger will assert. - // An alternative is to add a ADD pseudo instruction to replace kill - // markers. - return false; - } - return true; } + return true; +} - /// TransferDeadness - A identity copy definition is dead and it's being - /// removed. Find the last def or use and mark it as dead / kill. - void TransferDeadness(MachineBasicBlock *MBB, unsigned CurDist, - unsigned Reg, BitVector &RegKills, - std::vector &KillOps, - VirtRegMap &VRM) { - SmallPtrSet Seens; - SmallVector,8> Refs; - for (MachineRegisterInfo::reg_iterator RI = RegInfo->reg_begin(Reg), - RE = RegInfo->reg_end(); RI != RE; ++RI) { - MachineInstr *UDMI = &*RI; - if (UDMI->getParent() != MBB) - continue; - DenseMap::iterator DI = DistanceMap.find(UDMI); - if (DI == DistanceMap.end() || DI->second > CurDist) - continue; - if (Seens.insert(UDMI)) - Refs.push_back(std::make_pair(UDMI, DI->second)); - } +/// TransferDeadness - A identity copy definition is dead and it's being +/// removed. Find the last def or use and mark it as dead / kill. +void LocalRewriter:: +TransferDeadness(unsigned CurDist, + unsigned Reg, BitVector &RegKills, + std::vector &KillOps) { + SmallPtrSet Seens; + SmallVector,8> Refs; + for (MachineRegisterInfo::reg_iterator RI = MRI->reg_begin(Reg), + RE = MRI->reg_end(); RI != RE; ++RI) { + MachineInstr *UDMI = &*RI; + if (UDMI->getParent() != MBB) + continue; + DenseMap::iterator DI = DistanceMap.find(UDMI); + if (DI == DistanceMap.end() || DI->second > CurDist) + continue; + if (Seens.insert(UDMI)) + Refs.push_back(std::make_pair(UDMI, DI->second)); + } - if (Refs.empty()) - return; - std::sort(Refs.begin(), Refs.end(), RefSorter()); + if (Refs.empty()) + return; + std::sort(Refs.begin(), Refs.end(), RefSorter()); - while (!Refs.empty()) { - MachineInstr *LastUDMI = Refs.back().first; - Refs.pop_back(); + while (!Refs.empty()) { + MachineInstr *LastUDMI = Refs.back().first; + Refs.pop_back(); - MachineOperand *LastUD = NULL; - for (unsigned i = 0, e = LastUDMI->getNumOperands(); i != e; ++i) { - MachineOperand &MO = LastUDMI->getOperand(i); - if (!MO.isReg() || MO.getReg() != Reg) - continue; - if (!LastUD || (LastUD->isUse() && MO.isDef())) - LastUD = &MO; - if (LastUDMI->isRegTiedToDefOperand(i)) - break; - } - if (LastUD->isDef()) { - // If the instruction has no side effect, delete it and propagate - // backward further. Otherwise, mark is dead and we are done. - if (!isSafeToDelete(*LastUDMI)) { - LastUD->setIsDead(); - break; - } - VRM.RemoveMachineInstrFromMaps(LastUDMI); - MBB->erase(LastUDMI); - } else { - LastUD->setIsKill(); - RegKills.set(Reg); - KillOps[Reg] = LastUD; + MachineOperand *LastUD = NULL; + for (unsigned i = 0, e = LastUDMI->getNumOperands(); i != e; ++i) { + MachineOperand &MO = LastUDMI->getOperand(i); + if (!MO.isReg() || MO.getReg() != Reg) + continue; + if (!LastUD || (LastUD->isUse() && MO.isDef())) + LastUD = &MO; + if (LastUDMI->isRegTiedToDefOperand(i)) + break; + } + if (LastUD->isDef()) { + // If the instruction has no side effect, delete it and propagate + // backward further. Otherwise, mark is dead and we are done. + if (!isSafeToDelete(*LastUDMI)) { + LastUD->setIsDead(); break; } + VRM->RemoveMachineInstrFromMaps(LastUDMI); + MBB->erase(LastUDMI); + } else { + LastUD->setIsKill(); + RegKills.set(Reg); + KillOps[Reg] = LastUD; + break; } } +} - /// rewriteMBB - Keep track of which spills are available even after the - /// register allocator is done with them. If possible, avid reloading vregs. - void RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM, - LiveIntervals *LIs, - AvailableSpills &Spills, BitVector &RegKills, - std::vector &KillOps) { +/// rewriteMBB - Keep track of which spills are available even after the +/// register allocator is done with them. If possible, avid reloading vregs. +void +LocalRewriter::RewriteMBB(LiveIntervals *LIs, + AvailableSpills &Spills, BitVector &RegKills, + std::vector &KillOps) { + + DEBUG(dbgs() << "\n**** Local spiller rewriting MBB '" + << MBB->getName() << "':\n"); + + MachineFunction &MF = *MBB->getParent(); + + // MaybeDeadStores - When we need to write a value back into a stack slot, + // keep track of the inserted store. If the stack slot value is never read + // (because the value was used from some available register, for example), and + // subsequently stored to, the original store is dead. This map keeps track + // of inserted stores that are not used. If we see a subsequent store to the + // same stack slot, the original store is deleted. + std::vector MaybeDeadStores; + MaybeDeadStores.resize(MF.getFrameInfo()->getObjectIndexEnd(), NULL); + + // ReMatDefs - These are rematerializable def MIs which are not deleted. + SmallSet ReMatDefs; + + // Clear kill info. + SmallSet KilledMIRegs; + RegKills.reset(); + KillOps.clear(); + KillOps.resize(TRI->getNumRegs(), NULL); + + unsigned Dist = 0; + DistanceMap.clear(); + for (MachineBasicBlock::iterator MII = MBB->begin(), E = MBB->end(); + MII != E; ) { + MachineBasicBlock::iterator NextMII = llvm::next(MII); - DEBUG(dbgs() << "\n**** Local spiller rewriting MBB '" - << MBB.getName() << "':\n"); - - MachineFunction &MF = *MBB.getParent(); - - // MaybeDeadStores - When we need to write a value back into a stack slot, - // keep track of the inserted store. If the stack slot value is never read - // (because the value was used from some available register, for example), and - // subsequently stored to, the original store is dead. This map keeps track - // of inserted stores that are not used. If we see a subsequent store to the - // same stack slot, the original store is deleted. - std::vector MaybeDeadStores; - MaybeDeadStores.resize(MF.getFrameInfo()->getObjectIndexEnd(), NULL); - - // ReMatDefs - These are rematerializable def MIs which are not deleted. - SmallSet ReMatDefs; - - // Clear kill info. - SmallSet KilledMIRegs; - RegKills.reset(); - KillOps.clear(); - KillOps.resize(TRI->getNumRegs(), NULL); - - unsigned Dist = 0; - DistanceMap.clear(); - for (MachineBasicBlock::iterator MII = MBB.begin(), E = MBB.end(); - MII != E; ) { - MachineBasicBlock::iterator NextMII = llvm::next(MII); - - VirtRegMap::MI2VirtMapTy::const_iterator I, End; - bool Erased = false; - bool BackTracked = false; - if (OptimizeByUnfold(MBB, MII, - MaybeDeadStores, Spills, RegKills, KillOps, VRM)) - NextMII = llvm::next(MII); + VirtRegMap::MI2VirtMapTy::const_iterator I, End; + bool Erased = false; + bool BackTracked = false; + if (OptimizeByUnfold(MII, MaybeDeadStores, Spills, RegKills, KillOps)) + NextMII = llvm::next(MII); - MachineInstr &MI = *MII; - - if (VRM.hasEmergencySpills(&MI)) { - // Spill physical register(s) in the rare case the allocator has run out - // of registers to allocate. - SmallSet UsedSS; - std::vector &EmSpills = VRM.getEmergencySpills(&MI); - for (unsigned i = 0, e = EmSpills.size(); i != e; ++i) { - unsigned PhysReg = EmSpills[i]; - const TargetRegisterClass *RC = - TRI->getPhysicalRegisterRegClass(PhysReg); - assert(RC && "Unable to determine register class!"); - int SS = VRM.getEmergencySpillSlot(RC); - if (UsedSS.count(SS)) - llvm_unreachable("Need to spill more than one physical registers!"); - UsedSS.insert(SS); - TII->storeRegToStackSlot(MBB, MII, PhysReg, true, SS, RC); - MachineInstr *StoreMI = prior(MII); - VRM.addSpillSlotUse(SS, StoreMI); + MachineInstr &MI = *MII; - // Back-schedule reloads and remats. - MachineBasicBlock::iterator InsertLoc = - ComputeReloadLoc(llvm::next(MII), MBB.begin(), PhysReg, TRI, false, - SS, TII, MF); + if (VRM->hasEmergencySpills(&MI)) { + // Spill physical register(s) in the rare case the allocator has run out + // of registers to allocate. + SmallSet UsedSS; + std::vector &EmSpills = VRM->getEmergencySpills(&MI); + for (unsigned i = 0, e = EmSpills.size(); i != e; ++i) { + unsigned PhysReg = EmSpills[i]; + const TargetRegisterClass *RC = + TRI->getPhysicalRegisterRegClass(PhysReg); + assert(RC && "Unable to determine register class!"); + int SS = VRM->getEmergencySpillSlot(RC); + if (UsedSS.count(SS)) + llvm_unreachable("Need to spill more than one physical registers!"); + UsedSS.insert(SS); + TII->storeRegToStackSlot(*MBB, MII, PhysReg, true, SS, RC); + MachineInstr *StoreMI = prior(MII); + VRM->addSpillSlotUse(SS, StoreMI); - TII->loadRegFromStackSlot(MBB, InsertLoc, PhysReg, SS, RC); + // Back-schedule reloads and remats. + MachineBasicBlock::iterator InsertLoc = + ComputeReloadLoc(llvm::next(MII), MBB->begin(), PhysReg, TRI, false, + SS, TII, MF); - MachineInstr *LoadMI = prior(InsertLoc); - VRM.addSpillSlotUse(SS, LoadMI); - ++NumPSpills; - DistanceMap.insert(std::make_pair(LoadMI, Dist++)); - } - NextMII = llvm::next(MII); + TII->loadRegFromStackSlot(*MBB, InsertLoc, PhysReg, SS, RC); + + MachineInstr *LoadMI = prior(InsertLoc); + VRM->addSpillSlotUse(SS, LoadMI); + ++NumPSpills; + DistanceMap.insert(std::make_pair(LoadMI, Dist++)); } + NextMII = llvm::next(MII); + } - // Insert restores here if asked to. - if (VRM.isRestorePt(&MI)) { - std::vector &RestoreRegs = VRM.getRestorePtRestores(&MI); - for (unsigned i = 0, e = RestoreRegs.size(); i != e; ++i) { - unsigned VirtReg = RestoreRegs[e-i-1]; // Reverse order. - if (!VRM.getPreSplitReg(VirtReg)) - continue; // Split interval spilled again. - unsigned Phys = VRM.getPhys(VirtReg); - RegInfo->setPhysRegUsed(Phys); - - // Check if the value being restored if available. If so, it must be - // from a predecessor BB that fallthrough into this BB. We do not - // expect: - // BB1: - // r1 = load fi#1 - // ... - // = r1 - // ... # r1 not clobbered - // ... - // = load fi#1 - bool DoReMat = VRM.isReMaterialized(VirtReg); - int SSorRMId = DoReMat - ? VRM.getReMatId(VirtReg) : VRM.getStackSlot(VirtReg); - const TargetRegisterClass* RC = RegInfo->getRegClass(VirtReg); - unsigned InReg = Spills.getSpillSlotOrReMatPhysReg(SSorRMId); - if (InReg == Phys) { - // If the value is already available in the expected register, save - // a reload / remat. - if (SSorRMId) - DEBUG(dbgs() << "Reusing RM#" - << SSorRMId-VirtRegMap::MAX_STACK_SLOT-1); - else - DEBUG(dbgs() << "Reusing SS#" << SSorRMId); - DEBUG(dbgs() << " from physreg " - << TRI->getName(InReg) << " for vreg" - << VirtReg <<" instead of reloading into physreg " - << TRI->getName(Phys) << '\n'); - ++NumOmitted; - continue; - } else if (InReg && InReg != Phys) { - if (SSorRMId) - DEBUG(dbgs() << "Reusing RM#" - << SSorRMId-VirtRegMap::MAX_STACK_SLOT-1); - else - DEBUG(dbgs() << "Reusing SS#" << SSorRMId); - DEBUG(dbgs() << " from physreg " - << TRI->getName(InReg) << " for vreg" - << VirtReg <<" by copying it into physreg " - << TRI->getName(Phys) << '\n'); - - // If the reloaded / remat value is available in another register, - // copy it to the desired register. - - // Back-schedule reloads and remats. - MachineBasicBlock::iterator InsertLoc = - ComputeReloadLoc(MII, MBB.begin(), Phys, TRI, DoReMat, - SSorRMId, TII, MF); - - TII->copyRegToReg(MBB, InsertLoc, Phys, InReg, RC, RC); - - // This invalidates Phys. - Spills.ClobberPhysReg(Phys); - // Remember it's available. - Spills.addAvailable(SSorRMId, Phys); - - // Mark is killed. - MachineInstr *CopyMI = prior(InsertLoc); - CopyMI->setAsmPrinterFlag(MachineInstr::ReloadReuse); - MachineOperand *KillOpnd = CopyMI->findRegisterUseOperand(InReg); - KillOpnd->setIsKill(); - UpdateKills(*CopyMI, TRI, RegKills, KillOps); - - DEBUG(dbgs() << '\t' << *CopyMI); - ++NumCopified; - continue; - } + // Insert restores here if asked to. + if (VRM->isRestorePt(&MI)) { + std::vector &RestoreRegs = VRM->getRestorePtRestores(&MI); + for (unsigned i = 0, e = RestoreRegs.size(); i != e; ++i) { + unsigned VirtReg = RestoreRegs[e-i-1]; // Reverse order. + if (!VRM->getPreSplitReg(VirtReg)) + continue; // Split interval spilled again. + unsigned Phys = VRM->getPhys(VirtReg); + MRI->setPhysRegUsed(Phys); + + // Check if the value being restored if available. If so, it must be + // from a predecessor BB that fallthrough into this BB. We do not + // expect: + // BB1: + // r1 = load fi#1 + // ... + // = r1 + // ... # r1 not clobbered + // ... + // = load fi#1 + bool DoReMat = VRM->isReMaterialized(VirtReg); + int SSorRMId = DoReMat + ? VRM->getReMatId(VirtReg) : VRM->getStackSlot(VirtReg); + const TargetRegisterClass* RC = MRI->getRegClass(VirtReg); + unsigned InReg = Spills.getSpillSlotOrReMatPhysReg(SSorRMId); + if (InReg == Phys) { + // If the value is already available in the expected register, save + // a reload / remat. + if (SSorRMId) + DEBUG(dbgs() << "Reusing RM#" + << SSorRMId-VirtRegMap::MAX_STACK_SLOT-1); + else + DEBUG(dbgs() << "Reusing SS#" << SSorRMId); + DEBUG(dbgs() << " from physreg " + << TRI->getName(InReg) << " for vreg" + << VirtReg <<" instead of reloading into physreg " + << TRI->getName(Phys) << '\n'); + ++NumOmitted; + continue; + } else if (InReg && InReg != Phys) { + if (SSorRMId) + DEBUG(dbgs() << "Reusing RM#" + << SSorRMId-VirtRegMap::MAX_STACK_SLOT-1); + else + DEBUG(dbgs() << "Reusing SS#" << SSorRMId); + DEBUG(dbgs() << " from physreg " + << TRI->getName(InReg) << " for vreg" + << VirtReg <<" by copying it into physreg " + << TRI->getName(Phys) << '\n'); + + // If the reloaded / remat value is available in another register, + // copy it to the desired register. // Back-schedule reloads and remats. MachineBasicBlock::iterator InsertLoc = - ComputeReloadLoc(MII, MBB.begin(), Phys, TRI, DoReMat, + ComputeReloadLoc(MII, MBB->begin(), Phys, TRI, DoReMat, SSorRMId, TII, MF); - if (VRM.isReMaterialized(VirtReg)) { - ReMaterialize(MBB, InsertLoc, Phys, VirtReg, TII, TRI, VRM); - } else { - const TargetRegisterClass* RC = RegInfo->getRegClass(VirtReg); - TII->loadRegFromStackSlot(MBB, InsertLoc, Phys, SSorRMId, RC); - MachineInstr *LoadMI = prior(InsertLoc); - VRM.addSpillSlotUse(SSorRMId, LoadMI); - ++NumLoads; - DistanceMap.insert(std::make_pair(LoadMI, Dist++)); - } + TII->copyRegToReg(*MBB, InsertLoc, Phys, InReg, RC, RC); // This invalidates Phys. Spills.ClobberPhysReg(Phys); // Remember it's available. Spills.addAvailable(SSorRMId, Phys); - UpdateKills(*prior(InsertLoc), TRI, RegKills, KillOps); - DEBUG(dbgs() << '\t' << *prior(MII)); - } - } - - // Insert spills here if asked to. - if (VRM.isSpillPt(&MI)) { - std::vector > &SpillRegs = - VRM.getSpillPtSpills(&MI); - for (unsigned i = 0, e = SpillRegs.size(); i != e; ++i) { - unsigned VirtReg = SpillRegs[i].first; - bool isKill = SpillRegs[i].second; - if (!VRM.getPreSplitReg(VirtReg)) - continue; // Split interval spilled again. - const TargetRegisterClass *RC = RegInfo->getRegClass(VirtReg); - unsigned Phys = VRM.getPhys(VirtReg); - int StackSlot = VRM.getStackSlot(VirtReg); - MachineBasicBlock::iterator oldNextMII = llvm::next(MII); - TII->storeRegToStackSlot(MBB, llvm::next(MII), Phys, isKill, StackSlot, RC); - MachineInstr *StoreMI = prior(oldNextMII); - VRM.addSpillSlotUse(StackSlot, StoreMI); - DEBUG(dbgs() << "Store:\t" << *StoreMI); - VRM.virtFolded(VirtReg, StoreMI, VirtRegMap::isMod); - } - NextMII = llvm::next(MII); - } + // Mark is killed. + MachineInstr *CopyMI = prior(InsertLoc); + CopyMI->setAsmPrinterFlag(MachineInstr::ReloadReuse); + MachineOperand *KillOpnd = CopyMI->findRegisterUseOperand(InReg); + KillOpnd->setIsKill(); + UpdateKills(*CopyMI, TRI, RegKills, KillOps); - /// ReusedOperands - Keep track of operand reuse in case we need to undo - /// reuse. - ReuseInfo ReusedOperands(MI, TRI); - SmallVector VirtUseOps; - for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { - MachineOperand &MO = MI.getOperand(i); - if (!MO.isReg() || MO.getReg() == 0) - continue; // Ignore non-register operands. - - unsigned VirtReg = MO.getReg(); - if (TargetRegisterInfo::isPhysicalRegister(VirtReg)) { - // Ignore physregs for spilling, but remember that it is used by this - // function. - RegInfo->setPhysRegUsed(VirtReg); + DEBUG(dbgs() << '\t' << *CopyMI); + ++NumCopified; continue; } - // We want to process implicit virtual register uses first. - if (MO.isImplicit()) - // If the virtual register is implicitly defined, emit a implicit_def - // before so scavenger knows it's "defined". - // FIXME: This is a horrible hack done the by register allocator to - // remat a definition with virtual register operand. - VirtUseOps.insert(VirtUseOps.begin(), i); - else - VirtUseOps.push_back(i); - } + // Back-schedule reloads and remats. + MachineBasicBlock::iterator InsertLoc = + ComputeReloadLoc(MII, MBB->begin(), Phys, TRI, DoReMat, + SSorRMId, TII, MF); - // Process all of the spilled uses and all non spilled reg references. - SmallVector PotentialDeadStoreSlots; - KilledMIRegs.clear(); - for (unsigned j = 0, e = VirtUseOps.size(); j != e; ++j) { - unsigned i = VirtUseOps[j]; - unsigned VirtReg = MI.getOperand(i).getReg(); - assert(TargetRegisterInfo::isVirtualRegister(VirtReg) && - "Not a virtual register?"); - - unsigned SubIdx = MI.getOperand(i).getSubReg(); - if (VRM.isAssignedReg(VirtReg)) { - // This virtual register was assigned a physreg! - unsigned Phys = VRM.getPhys(VirtReg); - RegInfo->setPhysRegUsed(Phys); - if (MI.getOperand(i).isDef()) - ReusedOperands.markClobbered(Phys); - substitutePhysReg(MI.getOperand(i), Phys, *TRI); - if (VRM.isImplicitlyDefined(VirtReg)) - // FIXME: Is this needed? - BuildMI(MBB, &MI, MI.getDebugLoc(), - TII->get(TargetOpcode::IMPLICIT_DEF), Phys); - continue; + if (VRM->isReMaterialized(VirtReg)) { + ReMaterialize(*MBB, InsertLoc, Phys, VirtReg, TII, TRI, *VRM); + } else { + const TargetRegisterClass* RC = MRI->getRegClass(VirtReg); + TII->loadRegFromStackSlot(*MBB, InsertLoc, Phys, SSorRMId, RC); + MachineInstr *LoadMI = prior(InsertLoc); + VRM->addSpillSlotUse(SSorRMId, LoadMI); + ++NumLoads; + DistanceMap.insert(std::make_pair(LoadMI, Dist++)); } - // This virtual register is now known to be a spilled value. - if (!MI.getOperand(i).isUse()) - continue; // Handle defs in the loop below (handle use&def here though) - - bool AvoidReload = MI.getOperand(i).isUndef(); - // Check if it is defined by an implicit def. It should not be spilled. - // Note, this is for correctness reason. e.g. - // 8 %reg1024 = IMPLICIT_DEF - // 12 %reg1024 = INSERT_SUBREG %reg1024, %reg1025, 2 - // The live range [12, 14) are not part of the r1024 live interval since - // it's defined by an implicit def. It will not conflicts with live - // interval of r1025. Now suppose both registers are spilled, you can - // easily see a situation where both registers are reloaded before - // the INSERT_SUBREG and both target registers that would overlap. - bool DoReMat = VRM.isReMaterialized(VirtReg); - int SSorRMId = DoReMat - ? VRM.getReMatId(VirtReg) : VRM.getStackSlot(VirtReg); - int ReuseSlot = SSorRMId; - - // Check to see if this stack slot is available. - unsigned PhysReg = Spills.getSpillSlotOrReMatPhysReg(SSorRMId); - - // If this is a sub-register use, make sure the reuse register is in the - // right register class. For example, for x86 not all of the 32-bit - // registers have accessible sub-registers. - // Similarly so for EXTRACT_SUBREG. Consider this: - // EDI = op - // MOV32_mr fi#1, EDI - // ... - // = EXTRACT_SUBREG fi#1 - // fi#1 is available in EDI, but it cannot be reused because it's not in - // the right register file. - if (PhysReg && !AvoidReload && (SubIdx || MI.isExtractSubreg())) { - const TargetRegisterClass* RC = RegInfo->getRegClass(VirtReg); - if (!RC->contains(PhysReg)) - PhysReg = 0; - } + // This invalidates Phys. + Spills.ClobberPhysReg(Phys); + // Remember it's available. + Spills.addAvailable(SSorRMId, Phys); - if (PhysReg && !AvoidReload) { - // This spilled operand might be part of a two-address operand. If this - // is the case, then changing it will necessarily require changing the - // def part of the instruction as well. However, in some cases, we - // aren't allowed to modify the reused register. If none of these cases - // apply, reuse it. - bool CanReuse = true; - bool isTied = MI.isRegTiedToDefOperand(i); - if (isTied) { - // Okay, we have a two address operand. We can reuse this physreg as - // long as we are allowed to clobber the value and there isn't an - // earlier def that has already clobbered the physreg. - CanReuse = !ReusedOperands.isClobbered(PhysReg) && - Spills.canClobberPhysReg(PhysReg); - } - - if (CanReuse) { - // If this stack slot value is already available, reuse it! - if (ReuseSlot > VirtRegMap::MAX_STACK_SLOT) - DEBUG(dbgs() << "Reusing RM#" - << ReuseSlot-VirtRegMap::MAX_STACK_SLOT-1); - else - DEBUG(dbgs() << "Reusing SS#" << ReuseSlot); - DEBUG(dbgs() << " from physreg " - << TRI->getName(PhysReg) << " for vreg" - << VirtReg <<" instead of reloading into physreg " - << TRI->getName(VRM.getPhys(VirtReg)) << '\n'); - unsigned RReg = SubIdx ? TRI->getSubReg(PhysReg, SubIdx) : PhysReg; - MI.getOperand(i).setReg(RReg); - MI.getOperand(i).setSubReg(0); - - // The only technical detail we have is that we don't know that - // PhysReg won't be clobbered by a reloaded stack slot that occurs - // later in the instruction. In particular, consider 'op V1, V2'. - // If V1 is available in physreg R0, we would choose to reuse it - // here, instead of reloading it into the register the allocator - // indicated (say R1). However, V2 might have to be reloaded - // later, and it might indicate that it needs to live in R0. When - // this occurs, we need to have information available that - // indicates it is safe to use R1 for the reload instead of R0. - // - // To further complicate matters, we might conflict with an alias, - // or R0 and R1 might not be compatible with each other. In this - // case, we actually insert a reload for V1 in R1, ensuring that - // we can get at R0 or its alias. - ReusedOperands.addReuse(i, ReuseSlot, PhysReg, - VRM.getPhys(VirtReg), VirtReg); - if (isTied) - // Only mark it clobbered if this is a use&def operand. - ReusedOperands.markClobbered(PhysReg); - ++NumReused; - - if (MI.getOperand(i).isKill() && - ReuseSlot <= VirtRegMap::MAX_STACK_SLOT) { - - // The store of this spilled value is potentially dead, but we - // won't know for certain until we've confirmed that the re-use - // above is valid, which means waiting until the other operands - // are processed. For now we just track the spill slot, we'll - // remove it after the other operands are processed if valid. - - PotentialDeadStoreSlots.push_back(ReuseSlot); - } + UpdateKills(*prior(InsertLoc), TRI, RegKills, KillOps); + DEBUG(dbgs() << '\t' << *prior(MII)); + } + } - // Mark is isKill if it's there no other uses of the same virtual - // register and it's not a two-address operand. IsKill will be - // unset if reg is reused. - if (!isTied && KilledMIRegs.count(VirtReg) == 0) { - MI.getOperand(i).setIsKill(); - KilledMIRegs.insert(VirtReg); - } + // Insert spills here if asked to. + if (VRM->isSpillPt(&MI)) { + std::vector > &SpillRegs = + VRM->getSpillPtSpills(&MI); + for (unsigned i = 0, e = SpillRegs.size(); i != e; ++i) { + unsigned VirtReg = SpillRegs[i].first; + bool isKill = SpillRegs[i].second; + if (!VRM->getPreSplitReg(VirtReg)) + continue; // Split interval spilled again. + const TargetRegisterClass *RC = MRI->getRegClass(VirtReg); + unsigned Phys = VRM->getPhys(VirtReg); + int StackSlot = VRM->getStackSlot(VirtReg); + MachineBasicBlock::iterator oldNextMII = llvm::next(MII); + TII->storeRegToStackSlot(*MBB, llvm::next(MII), Phys, isKill, StackSlot, + RC); + MachineInstr *StoreMI = prior(oldNextMII); + VRM->addSpillSlotUse(StackSlot, StoreMI); + DEBUG(dbgs() << "Store:\t" << *StoreMI); + VRM->virtFolded(VirtReg, StoreMI, VirtRegMap::isMod); + } + NextMII = llvm::next(MII); + } - continue; - } // CanReuse - - // Otherwise we have a situation where we have a two-address instruction - // whose mod/ref operand needs to be reloaded. This reload is already - // available in some register "PhysReg", but if we used PhysReg as the - // operand to our 2-addr instruction, the instruction would modify - // PhysReg. This isn't cool if something later uses PhysReg and expects - // to get its initial value. - // - // To avoid this problem, and to avoid doing a load right after a store, - // we emit a copy from PhysReg into the designated register for this - // operand. - unsigned DesignatedReg = VRM.getPhys(VirtReg); - assert(DesignatedReg && "Must map virtreg to physreg!"); - - // Note that, if we reused a register for a previous operand, the - // register we want to reload into might not actually be - // available. If this occurs, use the register indicated by the - // reuser. - if (ReusedOperands.hasReuses()) - DesignatedReg = ReusedOperands.GetRegForReload(VirtReg, - DesignatedReg, &MI, - Spills, MaybeDeadStores, RegKills, KillOps, VRM); - - // If the mapped designated register is actually the physreg we have - // incoming, we don't need to inserted a dead copy. - if (DesignatedReg == PhysReg) { - // If this stack slot value is already available, reuse it! - if (ReuseSlot > VirtRegMap::MAX_STACK_SLOT) - DEBUG(dbgs() << "Reusing RM#" - << ReuseSlot-VirtRegMap::MAX_STACK_SLOT-1); - else - DEBUG(dbgs() << "Reusing SS#" << ReuseSlot); - DEBUG(dbgs() << " from physreg " << TRI->getName(PhysReg) - << " for vreg" << VirtReg - << " instead of reloading into same physreg.\n"); - unsigned RReg = SubIdx ? TRI->getSubReg(PhysReg, SubIdx) : PhysReg; - MI.getOperand(i).setReg(RReg); - MI.getOperand(i).setSubReg(0); - ReusedOperands.markClobbered(RReg); - ++NumReused; - continue; - } - - const TargetRegisterClass* RC = RegInfo->getRegClass(VirtReg); - RegInfo->setPhysRegUsed(DesignatedReg); - ReusedOperands.markClobbered(DesignatedReg); + /// ReusedOperands - Keep track of operand reuse in case we need to undo + /// reuse. + ReuseInfo ReusedOperands(MI, TRI); + SmallVector VirtUseOps; + for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { + MachineOperand &MO = MI.getOperand(i); + if (!MO.isReg() || MO.getReg() == 0) + continue; // Ignore non-register operands. - // Back-schedule reloads and remats. - MachineBasicBlock::iterator InsertLoc = - ComputeReloadLoc(&MI, MBB.begin(), PhysReg, TRI, DoReMat, - SSorRMId, TII, MF); + unsigned VirtReg = MO.getReg(); + if (TargetRegisterInfo::isPhysicalRegister(VirtReg)) { + // Ignore physregs for spilling, but remember that it is used by this + // function. + MRI->setPhysRegUsed(VirtReg); + continue; + } - TII->copyRegToReg(MBB, InsertLoc, DesignatedReg, PhysReg, RC, RC); + // We want to process implicit virtual register uses first. + if (MO.isImplicit()) + // If the virtual register is implicitly defined, emit a implicit_def + // before so scavenger knows it's "defined". + // FIXME: This is a horrible hack done the by register allocator to + // remat a definition with virtual register operand. + VirtUseOps.insert(VirtUseOps.begin(), i); + else + VirtUseOps.push_back(i); + } - MachineInstr *CopyMI = prior(InsertLoc); - CopyMI->setAsmPrinterFlag(MachineInstr::ReloadReuse); - UpdateKills(*CopyMI, TRI, RegKills, KillOps); + // Process all of the spilled uses and all non spilled reg references. + SmallVector PotentialDeadStoreSlots; + KilledMIRegs.clear(); + for (unsigned j = 0, e = VirtUseOps.size(); j != e; ++j) { + unsigned i = VirtUseOps[j]; + unsigned VirtReg = MI.getOperand(i).getReg(); + assert(TargetRegisterInfo::isVirtualRegister(VirtReg) && + "Not a virtual register?"); + + unsigned SubIdx = MI.getOperand(i).getSubReg(); + if (VRM->isAssignedReg(VirtReg)) { + // This virtual register was assigned a physreg! + unsigned Phys = VRM->getPhys(VirtReg); + MRI->setPhysRegUsed(Phys); + if (MI.getOperand(i).isDef()) + ReusedOperands.markClobbered(Phys); + substitutePhysReg(MI.getOperand(i), Phys, *TRI); + if (VRM->isImplicitlyDefined(VirtReg)) + // FIXME: Is this needed? + BuildMI(*MBB, &MI, MI.getDebugLoc(), + TII->get(TargetOpcode::IMPLICIT_DEF), Phys); + continue; + } + + // This virtual register is now known to be a spilled value. + if (!MI.getOperand(i).isUse()) + continue; // Handle defs in the loop below (handle use&def here though) + + bool AvoidReload = MI.getOperand(i).isUndef(); + // Check if it is defined by an implicit def. It should not be spilled. + // Note, this is for correctness reason. e.g. + // 8 %reg1024 = IMPLICIT_DEF + // 12 %reg1024 = INSERT_SUBREG %reg1024, %reg1025, 2 + // The live range [12, 14) are not part of the r1024 live interval since + // it's defined by an implicit def. It will not conflicts with live + // interval of r1025. Now suppose both registers are spilled, you can + // easily see a situation where both registers are reloaded before + // the INSERT_SUBREG and both target registers that would overlap. + bool DoReMat = VRM->isReMaterialized(VirtReg); + int SSorRMId = DoReMat + ? VRM->getReMatId(VirtReg) : VRM->getStackSlot(VirtReg); + int ReuseSlot = SSorRMId; + + // Check to see if this stack slot is available. + unsigned PhysReg = Spills.getSpillSlotOrReMatPhysReg(SSorRMId); + + // If this is a sub-register use, make sure the reuse register is in the + // right register class. For example, for x86 not all of the 32-bit + // registers have accessible sub-registers. + // Similarly so for EXTRACT_SUBREG. Consider this: + // EDI = op + // MOV32_mr fi#1, EDI + // ... + // = EXTRACT_SUBREG fi#1 + // fi#1 is available in EDI, but it cannot be reused because it's not in + // the right register file. + if (PhysReg && !AvoidReload && (SubIdx || MI.isExtractSubreg())) { + const TargetRegisterClass* RC = MRI->getRegClass(VirtReg); + if (!RC->contains(PhysReg)) + PhysReg = 0; + } - // This invalidates DesignatedReg. - Spills.ClobberPhysReg(DesignatedReg); - - Spills.addAvailable(ReuseSlot, DesignatedReg); - unsigned RReg = - SubIdx ? TRI->getSubReg(DesignatedReg, SubIdx) : DesignatedReg; + if (PhysReg && !AvoidReload) { + // This spilled operand might be part of a two-address operand. If this + // is the case, then changing it will necessarily require changing the + // def part of the instruction as well. However, in some cases, we + // aren't allowed to modify the reused register. If none of these cases + // apply, reuse it. + bool CanReuse = true; + bool isTied = MI.isRegTiedToDefOperand(i); + if (isTied) { + // Okay, we have a two address operand. We can reuse this physreg as + // long as we are allowed to clobber the value and there isn't an + // earlier def that has already clobbered the physreg. + CanReuse = !ReusedOperands.isClobbered(PhysReg) && + Spills.canClobberPhysReg(PhysReg); + } + + if (CanReuse) { + // If this stack slot value is already available, reuse it! + if (ReuseSlot > VirtRegMap::MAX_STACK_SLOT) + DEBUG(dbgs() << "Reusing RM#" + << ReuseSlot-VirtRegMap::MAX_STACK_SLOT-1); + else + DEBUG(dbgs() << "Reusing SS#" << ReuseSlot); + DEBUG(dbgs() << " from physreg " + << TRI->getName(PhysReg) << " for vreg" + << VirtReg <<" instead of reloading into physreg " + << TRI->getName(VRM->getPhys(VirtReg)) << '\n'); + unsigned RReg = SubIdx ? TRI->getSubReg(PhysReg, SubIdx) : PhysReg; MI.getOperand(i).setReg(RReg); MI.getOperand(i).setSubReg(0); - DEBUG(dbgs() << '\t' << *prior(MII)); + + // The only technical detail we have is that we don't know that + // PhysReg won't be clobbered by a reloaded stack slot that occurs + // later in the instruction. In particular, consider 'op V1, V2'. + // If V1 is available in physreg R0, we would choose to reuse it + // here, instead of reloading it into the register the allocator + // indicated (say R1). However, V2 might have to be reloaded + // later, and it might indicate that it needs to live in R0. When + // this occurs, we need to have information available that + // indicates it is safe to use R1 for the reload instead of R0. + // + // To further complicate matters, we might conflict with an alias, + // or R0 and R1 might not be compatible with each other. In this + // case, we actually insert a reload for V1 in R1, ensuring that + // we can get at R0 or its alias. + ReusedOperands.addReuse(i, ReuseSlot, PhysReg, + VRM->getPhys(VirtReg), VirtReg); + if (isTied) + // Only mark it clobbered if this is a use&def operand. + ReusedOperands.markClobbered(PhysReg); ++NumReused; + + if (MI.getOperand(i).isKill() && + ReuseSlot <= VirtRegMap::MAX_STACK_SLOT) { + + // The store of this spilled value is potentially dead, but we + // won't know for certain until we've confirmed that the re-use + // above is valid, which means waiting until the other operands + // are processed. For now we just track the spill slot, we'll + // remove it after the other operands are processed if valid. + + PotentialDeadStoreSlots.push_back(ReuseSlot); + } + + // Mark is isKill if it's there no other uses of the same virtual + // register and it's not a two-address operand. IsKill will be + // unset if reg is reused. + if (!isTied && KilledMIRegs.count(VirtReg) == 0) { + MI.getOperand(i).setIsKill(); + KilledMIRegs.insert(VirtReg); + } + continue; - } // if (PhysReg) - - // Otherwise, reload it and remember that we have it. - PhysReg = VRM.getPhys(VirtReg); - assert(PhysReg && "Must map virtreg to physreg!"); + } // CanReuse + + // Otherwise we have a situation where we have a two-address instruction + // whose mod/ref operand needs to be reloaded. This reload is already + // available in some register "PhysReg", but if we used PhysReg as the + // operand to our 2-addr instruction, the instruction would modify + // PhysReg. This isn't cool if something later uses PhysReg and expects + // to get its initial value. + // + // To avoid this problem, and to avoid doing a load right after a store, + // we emit a copy from PhysReg into the designated register for this + // operand. + unsigned DesignatedReg = VRM->getPhys(VirtReg); + assert(DesignatedReg && "Must map virtreg to physreg!"); // Note that, if we reused a register for a previous operand, the // register we want to reload into might not actually be // available. If this occurs, use the register indicated by the // reuser. if (ReusedOperands.hasReuses()) - PhysReg = ReusedOperands.GetRegForReload(VirtReg, PhysReg, &MI, - Spills, MaybeDeadStores, RegKills, KillOps, VRM); - - RegInfo->setPhysRegUsed(PhysReg); - ReusedOperands.markClobbered(PhysReg); - if (AvoidReload) - ++NumAvoided; - else { - // Back-schedule reloads and remats. - MachineBasicBlock::iterator InsertLoc = - ComputeReloadLoc(MII, MBB.begin(), PhysReg, TRI, DoReMat, - SSorRMId, TII, MF); + DesignatedReg = ReusedOperands. + GetRegForReload(VirtReg, DesignatedReg, &MI, Spills, + MaybeDeadStores, RegKills, KillOps, *VRM); + + // If the mapped designated register is actually the physreg we have + // incoming, we don't need to inserted a dead copy. + if (DesignatedReg == PhysReg) { + // If this stack slot value is already available, reuse it! + if (ReuseSlot > VirtRegMap::MAX_STACK_SLOT) + DEBUG(dbgs() << "Reusing RM#" + << ReuseSlot-VirtRegMap::MAX_STACK_SLOT-1); + else + DEBUG(dbgs() << "Reusing SS#" << ReuseSlot); + DEBUG(dbgs() << " from physreg " << TRI->getName(PhysReg) + << " for vreg" << VirtReg + << " instead of reloading into same physreg.\n"); + unsigned RReg = SubIdx ? TRI->getSubReg(PhysReg, SubIdx) : PhysReg; + MI.getOperand(i).setReg(RReg); + MI.getOperand(i).setSubReg(0); + ReusedOperands.markClobbered(RReg); + ++NumReused; + continue; + } - if (DoReMat) { - ReMaterialize(MBB, InsertLoc, PhysReg, VirtReg, TII, TRI, VRM); - } else { - const TargetRegisterClass* RC = RegInfo->getRegClass(VirtReg); - TII->loadRegFromStackSlot(MBB, InsertLoc, PhysReg, SSorRMId, RC); - MachineInstr *LoadMI = prior(InsertLoc); - VRM.addSpillSlotUse(SSorRMId, LoadMI); - ++NumLoads; - DistanceMap.insert(std::make_pair(LoadMI, Dist++)); - } - // This invalidates PhysReg. - Spills.ClobberPhysReg(PhysReg); + const TargetRegisterClass* RC = MRI->getRegClass(VirtReg); + MRI->setPhysRegUsed(DesignatedReg); + ReusedOperands.markClobbered(DesignatedReg); - // Any stores to this stack slot are not dead anymore. - if (!DoReMat) - MaybeDeadStores[SSorRMId] = NULL; - Spills.addAvailable(SSorRMId, PhysReg); - // Assumes this is the last use. IsKill will be unset if reg is reused - // unless it's a two-address operand. - if (!MI.isRegTiedToDefOperand(i) && - KilledMIRegs.count(VirtReg) == 0) { - MI.getOperand(i).setIsKill(); - KilledMIRegs.insert(VirtReg); - } + // Back-schedule reloads and remats. + MachineBasicBlock::iterator InsertLoc = + ComputeReloadLoc(&MI, MBB->begin(), PhysReg, TRI, DoReMat, + SSorRMId, TII, MF); - UpdateKills(*prior(InsertLoc), TRI, RegKills, KillOps); - DEBUG(dbgs() << '\t' << *prior(InsertLoc)); - } - unsigned RReg = SubIdx ? TRI->getSubReg(PhysReg, SubIdx) : PhysReg; + TII->copyRegToReg(*MBB, InsertLoc, DesignatedReg, PhysReg, RC, RC); + + MachineInstr *CopyMI = prior(InsertLoc); + CopyMI->setAsmPrinterFlag(MachineInstr::ReloadReuse); + UpdateKills(*CopyMI, TRI, RegKills, KillOps); + + // This invalidates DesignatedReg. + Spills.ClobberPhysReg(DesignatedReg); + + Spills.addAvailable(ReuseSlot, DesignatedReg); + unsigned RReg = + SubIdx ? TRI->getSubReg(DesignatedReg, SubIdx) : DesignatedReg; MI.getOperand(i).setReg(RReg); MI.getOperand(i).setSubReg(0); - } + DEBUG(dbgs() << '\t' << *prior(MII)); + ++NumReused; + continue; + } // if (PhysReg) - // Ok - now we can remove stores that have been confirmed dead. - for (unsigned j = 0, e = PotentialDeadStoreSlots.size(); j != e; ++j) { - // This was the last use and the spilled value is still available - // for reuse. That means the spill was unnecessary! - int PDSSlot = PotentialDeadStoreSlots[j]; - MachineInstr* DeadStore = MaybeDeadStores[PDSSlot]; - if (DeadStore) { - DEBUG(dbgs() << "Removed dead store:\t" << *DeadStore); - InvalidateKills(*DeadStore, TRI, RegKills, KillOps); - VRM.RemoveMachineInstrFromMaps(DeadStore); - MBB.erase(DeadStore); - MaybeDeadStores[PDSSlot] = NULL; - ++NumDSE; + // Otherwise, reload it and remember that we have it. + PhysReg = VRM->getPhys(VirtReg); + assert(PhysReg && "Must map virtreg to physreg!"); + + // Note that, if we reused a register for a previous operand, the + // register we want to reload into might not actually be + // available. If this occurs, use the register indicated by the + // reuser. + if (ReusedOperands.hasReuses()) + PhysReg = ReusedOperands.GetRegForReload(VirtReg, PhysReg, &MI, + Spills, MaybeDeadStores, RegKills, KillOps, *VRM); + + MRI->setPhysRegUsed(PhysReg); + ReusedOperands.markClobbered(PhysReg); + if (AvoidReload) + ++NumAvoided; + else { + // Back-schedule reloads and remats. + MachineBasicBlock::iterator InsertLoc = + ComputeReloadLoc(MII, MBB->begin(), PhysReg, TRI, DoReMat, + SSorRMId, TII, MF); + + if (DoReMat) { + ReMaterialize(*MBB, InsertLoc, PhysReg, VirtReg, TII, TRI, *VRM); + } else { + const TargetRegisterClass* RC = MRI->getRegClass(VirtReg); + TII->loadRegFromStackSlot(*MBB, InsertLoc, PhysReg, SSorRMId, RC); + MachineInstr *LoadMI = prior(InsertLoc); + VRM->addSpillSlotUse(SSorRMId, LoadMI); + ++NumLoads; + DistanceMap.insert(std::make_pair(LoadMI, Dist++)); + } + // This invalidates PhysReg. + Spills.ClobberPhysReg(PhysReg); + + // Any stores to this stack slot are not dead anymore. + if (!DoReMat) + MaybeDeadStores[SSorRMId] = NULL; + Spills.addAvailable(SSorRMId, PhysReg); + // Assumes this is the last use. IsKill will be unset if reg is reused + // unless it's a two-address operand. + if (!MI.isRegTiedToDefOperand(i) && + KilledMIRegs.count(VirtReg) == 0) { + MI.getOperand(i).setIsKill(); + KilledMIRegs.insert(VirtReg); } + + UpdateKills(*prior(InsertLoc), TRI, RegKills, KillOps); + DEBUG(dbgs() << '\t' << *prior(InsertLoc)); } + unsigned RReg = SubIdx ? TRI->getSubReg(PhysReg, SubIdx) : PhysReg; + MI.getOperand(i).setReg(RReg); + MI.getOperand(i).setSubReg(0); + } + // Ok - now we can remove stores that have been confirmed dead. + for (unsigned j = 0, e = PotentialDeadStoreSlots.size(); j != e; ++j) { + // This was the last use and the spilled value is still available + // for reuse. That means the spill was unnecessary! + int PDSSlot = PotentialDeadStoreSlots[j]; + MachineInstr* DeadStore = MaybeDeadStores[PDSSlot]; + if (DeadStore) { + DEBUG(dbgs() << "Removed dead store:\t" << *DeadStore); + InvalidateKills(*DeadStore, TRI, RegKills, KillOps); + VRM->RemoveMachineInstrFromMaps(DeadStore); + MBB->erase(DeadStore); + MaybeDeadStores[PDSSlot] = NULL; + ++NumDSE; + } + } - DEBUG(dbgs() << '\t' << MI); + DEBUG(dbgs() << '\t' << MI); - // If we have folded references to memory operands, make sure we clear all - // physical registers that may contain the value of the spilled virtual - // register - SmallSet FoldedSS; - for (tie(I, End) = VRM.getFoldedVirts(&MI); I != End; ) { - unsigned VirtReg = I->second.first; - VirtRegMap::ModRef MR = I->second.second; - DEBUG(dbgs() << "Folded vreg: " << VirtReg << " MR: " << MR); - // MI2VirtMap be can updated which invalidate the iterator. - // Increment the iterator first. - ++I; - int SS = VRM.getStackSlot(VirtReg); - if (SS == VirtRegMap::NO_STACK_SLOT) - continue; - FoldedSS.insert(SS); - DEBUG(dbgs() << " - StackSlot: " << SS << "\n"); - - // If this folded instruction is just a use, check to see if it's a - // straight load from the virt reg slot. - if ((MR & VirtRegMap::isRef) && !(MR & VirtRegMap::isMod)) { - int FrameIdx; - unsigned DestReg = TII->isLoadFromStackSlot(&MI, FrameIdx); - if (DestReg && FrameIdx == SS) { - // If this spill slot is available, turn it into a copy (or nothing) - // instead of leaving it as a load! - if (unsigned InReg = Spills.getSpillSlotOrReMatPhysReg(SS)) { - DEBUG(dbgs() << "Promoted Load To Copy: " << MI); - if (DestReg != InReg) { - const TargetRegisterClass *RC = RegInfo->getRegClass(VirtReg); - TII->copyRegToReg(MBB, &MI, DestReg, InReg, RC, RC); - MachineOperand *DefMO = MI.findRegisterDefOperand(DestReg); - unsigned SubIdx = DefMO->getSubReg(); - // Revisit the copy so we make sure to notice the effects of the - // operation on the destreg (either needing to RA it if it's - // virtual or needing to clobber any values if it's physical). - NextMII = &MI; - --NextMII; // backtrack to the copy. - NextMII->setAsmPrinterFlag(MachineInstr::ReloadReuse); - // Propagate the sub-register index over. - if (SubIdx) { - DefMO = NextMII->findRegisterDefOperand(DestReg); - DefMO->setSubReg(SubIdx); - } - - // Mark is killed. - MachineOperand *KillOpnd = NextMII->findRegisterUseOperand(InReg); - KillOpnd->setIsKill(); - - BackTracked = true; - } else { - DEBUG(dbgs() << "Removing now-noop copy: " << MI); - // Unset last kill since it's being reused. - InvalidateKill(InReg, TRI, RegKills, KillOps); - Spills.disallowClobberPhysReg(InReg); + // If we have folded references to memory operands, make sure we clear all + // physical registers that may contain the value of the spilled virtual + // register + SmallSet FoldedSS; + for (tie(I, End) = VRM->getFoldedVirts(&MI); I != End; ) { + unsigned VirtReg = I->second.first; + VirtRegMap::ModRef MR = I->second.second; + DEBUG(dbgs() << "Folded vreg: " << VirtReg << " MR: " << MR); + + // MI2VirtMap be can updated which invalidate the iterator. + // Increment the iterator first. + ++I; + int SS = VRM->getStackSlot(VirtReg); + if (SS == VirtRegMap::NO_STACK_SLOT) + continue; + FoldedSS.insert(SS); + DEBUG(dbgs() << " - StackSlot: " << SS << "\n"); + + // If this folded instruction is just a use, check to see if it's a + // straight load from the virt reg slot. + if ((MR & VirtRegMap::isRef) && !(MR & VirtRegMap::isMod)) { + int FrameIdx; + unsigned DestReg = TII->isLoadFromStackSlot(&MI, FrameIdx); + if (DestReg && FrameIdx == SS) { + // If this spill slot is available, turn it into a copy (or nothing) + // instead of leaving it as a load! + if (unsigned InReg = Spills.getSpillSlotOrReMatPhysReg(SS)) { + DEBUG(dbgs() << "Promoted Load To Copy: " << MI); + if (DestReg != InReg) { + const TargetRegisterClass *RC = MRI->getRegClass(VirtReg); + TII->copyRegToReg(*MBB, &MI, DestReg, InReg, RC, RC); + MachineOperand *DefMO = MI.findRegisterDefOperand(DestReg); + unsigned SubIdx = DefMO->getSubReg(); + // Revisit the copy so we make sure to notice the effects of the + // operation on the destreg (either needing to RA it if it's + // virtual or needing to clobber any values if it's physical). + NextMII = &MI; + --NextMII; // backtrack to the copy. + NextMII->setAsmPrinterFlag(MachineInstr::ReloadReuse); + // Propagate the sub-register index over. + if (SubIdx) { + DefMO = NextMII->findRegisterDefOperand(DestReg); + DefMO->setSubReg(SubIdx); } - InvalidateKills(MI, TRI, RegKills, KillOps); - VRM.RemoveMachineInstrFromMaps(&MI); - MBB.erase(&MI); - Erased = true; - goto ProcessNextInst; + // Mark is killed. + MachineOperand *KillOpnd = NextMII->findRegisterUseOperand(InReg); + KillOpnd->setIsKill(); + + BackTracked = true; + } else { + DEBUG(dbgs() << "Removing now-noop copy: " << MI); + // Unset last kill since it's being reused. + InvalidateKill(InReg, TRI, RegKills, KillOps); + Spills.disallowClobberPhysReg(InReg); } - } else { - unsigned PhysReg = Spills.getSpillSlotOrReMatPhysReg(SS); - SmallVector NewMIs; - if (PhysReg && - TII->unfoldMemoryOperand(MF, &MI, PhysReg, false, false, NewMIs)) { - MBB.insert(MII, NewMIs[0]); + + InvalidateKills(MI, TRI, RegKills, KillOps); + VRM->RemoveMachineInstrFromMaps(&MI); + MBB->erase(&MI); + Erased = true; + goto ProcessNextInst; + } + } else { + unsigned PhysReg = Spills.getSpillSlotOrReMatPhysReg(SS); + SmallVector NewMIs; + if (PhysReg && + TII->unfoldMemoryOperand(MF, &MI, PhysReg, false, false, NewMIs)) { + MBB->insert(MII, NewMIs[0]); + InvalidateKills(MI, TRI, RegKills, KillOps); + VRM->RemoveMachineInstrFromMaps(&MI); + MBB->erase(&MI); + Erased = true; + --NextMII; // backtrack to the unfolded instruction. + BackTracked = true; + goto ProcessNextInst; + } + } + } + + // If this reference is not a use, any previous store is now dead. + // Otherwise, the store to this stack slot is not dead anymore. + MachineInstr* DeadStore = MaybeDeadStores[SS]; + if (DeadStore) { + bool isDead = !(MR & VirtRegMap::isRef); + MachineInstr *NewStore = NULL; + if (MR & VirtRegMap::isModRef) { + unsigned PhysReg = Spills.getSpillSlotOrReMatPhysReg(SS); + SmallVector NewMIs; + // We can reuse this physreg as long as we are allowed to clobber + // the value and there isn't an earlier def that has already clobbered + // the physreg. + if (PhysReg && + !ReusedOperands.isClobbered(PhysReg) && + Spills.canClobberPhysReg(PhysReg) && + !TII->isStoreToStackSlot(&MI, SS)) { // Not profitable! + MachineOperand *KillOpnd = + DeadStore->findRegisterUseOperand(PhysReg, true); + // Note, if the store is storing a sub-register, it's possible the + // super-register is needed below. + if (KillOpnd && !KillOpnd->getSubReg() && + TII->unfoldMemoryOperand(MF, &MI, PhysReg, false, true,NewMIs)){ + MBB->insert(MII, NewMIs[0]); + NewStore = NewMIs[1]; + MBB->insert(MII, NewStore); + VRM->addSpillSlotUse(SS, NewStore); InvalidateKills(MI, TRI, RegKills, KillOps); - VRM.RemoveMachineInstrFromMaps(&MI); - MBB.erase(&MI); + VRM->RemoveMachineInstrFromMaps(&MI); + MBB->erase(&MI); Erased = true; + --NextMII; --NextMII; // backtrack to the unfolded instruction. BackTracked = true; - goto ProcessNextInst; + isDead = true; + ++NumSUnfold; } } } - // If this reference is not a use, any previous store is now dead. - // Otherwise, the store to this stack slot is not dead anymore. - MachineInstr* DeadStore = MaybeDeadStores[SS]; - if (DeadStore) { - bool isDead = !(MR & VirtRegMap::isRef); - MachineInstr *NewStore = NULL; - if (MR & VirtRegMap::isModRef) { - unsigned PhysReg = Spills.getSpillSlotOrReMatPhysReg(SS); - SmallVector NewMIs; - // We can reuse this physreg as long as we are allowed to clobber - // the value and there isn't an earlier def that has already clobbered - // the physreg. - if (PhysReg && - !ReusedOperands.isClobbered(PhysReg) && - Spills.canClobberPhysReg(PhysReg) && - !TII->isStoreToStackSlot(&MI, SS)) { // Not profitable! - MachineOperand *KillOpnd = - DeadStore->findRegisterUseOperand(PhysReg, true); - // Note, if the store is storing a sub-register, it's possible the - // super-register is needed below. - if (KillOpnd && !KillOpnd->getSubReg() && - TII->unfoldMemoryOperand(MF, &MI, PhysReg, false, true,NewMIs)){ - MBB.insert(MII, NewMIs[0]); - NewStore = NewMIs[1]; - MBB.insert(MII, NewStore); - VRM.addSpillSlotUse(SS, NewStore); - InvalidateKills(MI, TRI, RegKills, KillOps); - VRM.RemoveMachineInstrFromMaps(&MI); - MBB.erase(&MI); - Erased = true; - --NextMII; - --NextMII; // backtrack to the unfolded instruction. - BackTracked = true; - isDead = true; - ++NumSUnfold; - } + if (isDead) { // Previous store is dead. + // If we get here, the store is dead, nuke it now. + DEBUG(dbgs() << "Removed dead store:\t" << *DeadStore); + InvalidateKills(*DeadStore, TRI, RegKills, KillOps); + VRM->RemoveMachineInstrFromMaps(DeadStore); + MBB->erase(DeadStore); + if (!NewStore) + ++NumDSE; + } + + MaybeDeadStores[SS] = NULL; + if (NewStore) { + // Treat this store as a spill merged into a copy. That makes the + // stack slot value available. + VRM->virtFolded(VirtReg, NewStore, VirtRegMap::isMod); + goto ProcessNextInst; + } + } + + // If the spill slot value is available, and this is a new definition of + // the value, the value is not available anymore. + if (MR & VirtRegMap::isMod) { + // Notice that the value in this stack slot has been modified. + Spills.ModifyStackSlotOrReMat(SS); + + // If this is *just* a mod of the value, check to see if this is just a + // store to the spill slot (i.e. the spill got merged into the copy). If + // so, realize that the vreg is available now, and add the store to the + // MaybeDeadStore info. + int StackSlot; + if (!(MR & VirtRegMap::isRef)) { + if (unsigned SrcReg = TII->isStoreToStackSlot(&MI, StackSlot)) { + assert(TargetRegisterInfo::isPhysicalRegister(SrcReg) && + "Src hasn't been allocated yet?"); + + if (CommuteToFoldReload(MII, VirtReg, SrcReg, StackSlot, + Spills, RegKills, KillOps, TRI)) { + NextMII = llvm::next(MII); + BackTracked = true; + goto ProcessNextInst; } - } - if (isDead) { // Previous store is dead. - // If we get here, the store is dead, nuke it now. - DEBUG(dbgs() << "Removed dead store:\t" << *DeadStore); - InvalidateKills(*DeadStore, TRI, RegKills, KillOps); - VRM.RemoveMachineInstrFromMaps(DeadStore); - MBB.erase(DeadStore); - if (!NewStore) - ++NumDSE; + // Okay, this is certainly a store of SrcReg to [StackSlot]. Mark + // this as a potentially dead store in case there is a subsequent + // store into the stack slot without a read from it. + MaybeDeadStores[StackSlot] = &MI; + + // If the stack slot value was previously available in some other + // register, change it now. Otherwise, make the register + // available in PhysReg. + Spills.addAvailable(StackSlot, SrcReg, MI.killsRegister(SrcReg)); } + } + } + } - MaybeDeadStores[SS] = NULL; - if (NewStore) { - // Treat this store as a spill merged into a copy. That makes the - // stack slot value available. - VRM.virtFolded(VirtReg, NewStore, VirtRegMap::isMod); - goto ProcessNextInst; + // Process all of the spilled defs. + for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { + MachineOperand &MO = MI.getOperand(i); + if (!(MO.isReg() && MO.getReg() && MO.isDef())) + continue; + + unsigned VirtReg = MO.getReg(); + if (!TargetRegisterInfo::isVirtualRegister(VirtReg)) { + // Check to see if this is a noop copy. If so, eliminate the + // instruction before considering the dest reg to be changed. + // Also check if it's copying from an "undef", if so, we can't + // eliminate this or else the undef marker is lost and it will + // confuses the scavenger. This is extremely rare. + unsigned Src, Dst, SrcSR, DstSR; + if (TII->isMoveInstr(MI, Src, Dst, SrcSR, DstSR) && Src == Dst && + !MI.findRegisterUseOperand(Src)->isUndef()) { + ++NumDCE; + DEBUG(dbgs() << "Removing now-noop copy: " << MI); + SmallVector KillRegs; + InvalidateKills(MI, TRI, RegKills, KillOps, &KillRegs); + if (MO.isDead() && !KillRegs.empty()) { + // Source register or an implicit super/sub-register use is killed. + assert(KillRegs[0] == Dst || + TRI->isSubRegister(KillRegs[0], Dst) || + TRI->isSuperRegister(KillRegs[0], Dst)); + // Last def is now dead. + TransferDeadness(Dist, Src, RegKills, KillOps); } + VRM->RemoveMachineInstrFromMaps(&MI); + MBB->erase(&MI); + Erased = true; + Spills.disallowClobberPhysReg(VirtReg); + goto ProcessNextInst; } - // If the spill slot value is available, and this is a new definition of - // the value, the value is not available anymore. - if (MR & VirtRegMap::isMod) { - // Notice that the value in this stack slot has been modified. - Spills.ModifyStackSlotOrReMat(SS); - - // If this is *just* a mod of the value, check to see if this is just a - // store to the spill slot (i.e. the spill got merged into the copy). If - // so, realize that the vreg is available now, and add the store to the - // MaybeDeadStore info. - int StackSlot; - if (!(MR & VirtRegMap::isRef)) { - if (unsigned SrcReg = TII->isStoreToStackSlot(&MI, StackSlot)) { - assert(TargetRegisterInfo::isPhysicalRegister(SrcReg) && - "Src hasn't been allocated yet?"); - - if (CommuteToFoldReload(MBB, MII, VirtReg, SrcReg, StackSlot, - Spills, RegKills, KillOps, TRI, VRM)) { - NextMII = llvm::next(MII); - BackTracked = true; - goto ProcessNextInst; - } + // If it's not a no-op copy, it clobbers the value in the destreg. + Spills.ClobberPhysReg(VirtReg); + ReusedOperands.markClobbered(VirtReg); + + // Check to see if this instruction is a load from a stack slot into + // a register. If so, this provides the stack slot value in the reg. + int FrameIdx; + if (unsigned DestReg = TII->isLoadFromStackSlot(&MI, FrameIdx)) { + assert(DestReg == VirtReg && "Unknown load situation!"); + + // If it is a folded reference, then it's not safe to clobber. + bool Folded = FoldedSS.count(FrameIdx); + // Otherwise, if it wasn't available, remember that it is now! + Spills.addAvailable(FrameIdx, DestReg, !Folded); + goto ProcessNextInst; + } - // Okay, this is certainly a store of SrcReg to [StackSlot]. Mark - // this as a potentially dead store in case there is a subsequent - // store into the stack slot without a read from it. - MaybeDeadStores[StackSlot] = &MI; + continue; + } - // If the stack slot value was previously available in some other - // register, change it now. Otherwise, make the register - // available in PhysReg. - Spills.addAvailable(StackSlot, SrcReg, MI.killsRegister(SrcReg)); - } - } + unsigned SubIdx = MO.getSubReg(); + bool DoReMat = VRM->isReMaterialized(VirtReg); + if (DoReMat) + ReMatDefs.insert(&MI); + + // The only vregs left are stack slot definitions. + int StackSlot = VRM->getStackSlot(VirtReg); + const TargetRegisterClass *RC = MRI->getRegClass(VirtReg); + + // If this def is part of a two-address operand, make sure to execute + // the store from the correct physical register. + unsigned PhysReg; + unsigned TiedOp; + if (MI.isRegTiedToUseOperand(i, &TiedOp)) { + PhysReg = MI.getOperand(TiedOp).getReg(); + if (SubIdx) { + unsigned SuperReg = findSuperReg(RC, PhysReg, SubIdx, TRI); + assert(SuperReg && TRI->getSubReg(SuperReg, SubIdx) == PhysReg && + "Can't find corresponding super-register!"); + PhysReg = SuperReg; + } + } else { + PhysReg = VRM->getPhys(VirtReg); + if (ReusedOperands.isClobbered(PhysReg)) { + // Another def has taken the assigned physreg. It must have been a + // use&def which got it due to reuse. Undo the reuse! + PhysReg = ReusedOperands.GetRegForReload(VirtReg, PhysReg, &MI, + Spills, MaybeDeadStores, RegKills, KillOps, *VRM); } } - // Process all of the spilled defs. - for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { - MachineOperand &MO = MI.getOperand(i); - if (!(MO.isReg() && MO.getReg() && MO.isDef())) - continue; + assert(PhysReg && "VR not assigned a physical register?"); + MRI->setPhysRegUsed(PhysReg); + unsigned RReg = SubIdx ? TRI->getSubReg(PhysReg, SubIdx) : PhysReg; + ReusedOperands.markClobbered(RReg); + MI.getOperand(i).setReg(RReg); + MI.getOperand(i).setSubReg(0); + + if (!MO.isDead()) { + MachineInstr *&LastStore = MaybeDeadStores[StackSlot]; + SpillRegToStackSlot(MII, -1, PhysReg, StackSlot, RC, true, + LastStore, Spills, ReMatDefs, RegKills, KillOps); + NextMII = llvm::next(MII); - unsigned VirtReg = MO.getReg(); - if (!TargetRegisterInfo::isVirtualRegister(VirtReg)) { - // Check to see if this is a noop copy. If so, eliminate the - // instruction before considering the dest reg to be changed. - // Also check if it's copying from an "undef", if so, we can't - // eliminate this or else the undef marker is lost and it will - // confuses the scavenger. This is extremely rare. + // Check to see if this is a noop copy. If so, eliminate the + // instruction before considering the dest reg to be changed. + { unsigned Src, Dst, SrcSR, DstSR; - if (TII->isMoveInstr(MI, Src, Dst, SrcSR, DstSR) && Src == Dst && - !MI.findRegisterUseOperand(Src)->isUndef()) { + if (TII->isMoveInstr(MI, Src, Dst, SrcSR, DstSR) && Src == Dst) { ++NumDCE; DEBUG(dbgs() << "Removing now-noop copy: " << MI); - SmallVector KillRegs; - InvalidateKills(MI, TRI, RegKills, KillOps, &KillRegs); - if (MO.isDead() && !KillRegs.empty()) { - // Source register or an implicit super/sub-register use is killed. - assert(KillRegs[0] == Dst || - TRI->isSubRegister(KillRegs[0], Dst) || - TRI->isSuperRegister(KillRegs[0], Dst)); - // Last def is now dead. - TransferDeadness(&MBB, Dist, Src, RegKills, KillOps, VRM); - } - VRM.RemoveMachineInstrFromMaps(&MI); - MBB.erase(&MI); + InvalidateKills(MI, TRI, RegKills, KillOps); + VRM->RemoveMachineInstrFromMaps(&MI); + MBB->erase(&MI); Erased = true; - Spills.disallowClobberPhysReg(VirtReg); + UpdateKills(*LastStore, TRI, RegKills, KillOps); goto ProcessNextInst; } - - // If it's not a no-op copy, it clobbers the value in the destreg. - Spills.ClobberPhysReg(VirtReg); - ReusedOperands.markClobbered(VirtReg); - - // Check to see if this instruction is a load from a stack slot into - // a register. If so, this provides the stack slot value in the reg. - int FrameIdx; - if (unsigned DestReg = TII->isLoadFromStackSlot(&MI, FrameIdx)) { - assert(DestReg == VirtReg && "Unknown load situation!"); - - // If it is a folded reference, then it's not safe to clobber. - bool Folded = FoldedSS.count(FrameIdx); - // Otherwise, if it wasn't available, remember that it is now! - Spills.addAvailable(FrameIdx, DestReg, !Folded); - goto ProcessNextInst; - } - - continue; - } - - unsigned SubIdx = MO.getSubReg(); - bool DoReMat = VRM.isReMaterialized(VirtReg); - if (DoReMat) - ReMatDefs.insert(&MI); - - // The only vregs left are stack slot definitions. - int StackSlot = VRM.getStackSlot(VirtReg); - const TargetRegisterClass *RC = RegInfo->getRegClass(VirtReg); - - // If this def is part of a two-address operand, make sure to execute - // the store from the correct physical register. - unsigned PhysReg; - unsigned TiedOp; - if (MI.isRegTiedToUseOperand(i, &TiedOp)) { - PhysReg = MI.getOperand(TiedOp).getReg(); - if (SubIdx) { - unsigned SuperReg = findSuperReg(RC, PhysReg, SubIdx, TRI); - assert(SuperReg && TRI->getSubReg(SuperReg, SubIdx) == PhysReg && - "Can't find corresponding super-register!"); - PhysReg = SuperReg; - } - } else { - PhysReg = VRM.getPhys(VirtReg); - if (ReusedOperands.isClobbered(PhysReg)) { - // Another def has taken the assigned physreg. It must have been a - // use&def which got it due to reuse. Undo the reuse! - PhysReg = ReusedOperands.GetRegForReload(VirtReg, PhysReg, &MI, - Spills, MaybeDeadStores, RegKills, KillOps, VRM); - } } - - assert(PhysReg && "VR not assigned a physical register?"); - RegInfo->setPhysRegUsed(PhysReg); - unsigned RReg = SubIdx ? TRI->getSubReg(PhysReg, SubIdx) : PhysReg; - ReusedOperands.markClobbered(RReg); - MI.getOperand(i).setReg(RReg); - MI.getOperand(i).setSubReg(0); - - if (!MO.isDead()) { - MachineInstr *&LastStore = MaybeDeadStores[StackSlot]; - SpillRegToStackSlot(MBB, MII, -1, PhysReg, StackSlot, RC, true, - LastStore, Spills, ReMatDefs, RegKills, KillOps, VRM); - NextMII = llvm::next(MII); - - // Check to see if this is a noop copy. If so, eliminate the - // instruction before considering the dest reg to be changed. - { - unsigned Src, Dst, SrcSR, DstSR; - if (TII->isMoveInstr(MI, Src, Dst, SrcSR, DstSR) && Src == Dst) { - ++NumDCE; - DEBUG(dbgs() << "Removing now-noop copy: " << MI); - InvalidateKills(MI, TRI, RegKills, KillOps); - VRM.RemoveMachineInstrFromMaps(&MI); - MBB.erase(&MI); - Erased = true; - UpdateKills(*LastStore, TRI, RegKills, KillOps); - goto ProcessNextInst; - } - } - } } + } ProcessNextInst: - // Delete dead instructions without side effects. - if (!Erased && !BackTracked && isSafeToDelete(MI)) { - InvalidateKills(MI, TRI, RegKills, KillOps); - VRM.RemoveMachineInstrFromMaps(&MI); - MBB.erase(&MI); - Erased = true; - } - if (!Erased) - DistanceMap.insert(std::make_pair(&MI, Dist++)); - if (!Erased && !BackTracked) { - for (MachineBasicBlock::iterator II = &MI; II != NextMII; ++II) - UpdateKills(*II, TRI, RegKills, KillOps); - } - MII = NextMII; + // Delete dead instructions without side effects. + if (!Erased && !BackTracked && isSafeToDelete(MI)) { + InvalidateKills(MI, TRI, RegKills, KillOps); + VRM->RemoveMachineInstrFromMaps(&MI); + MBB->erase(&MI); + Erased = true; } - + if (!Erased) + DistanceMap.insert(std::make_pair(&MI, Dist++)); + if (!Erased && !BackTracked) { + for (MachineBasicBlock::iterator II = &MI; II != NextMII; ++II) + UpdateKills(*II, TRI, RegKills, KillOps); + } + MII = NextMII; } -}; - } llvm::VirtRegRewriter* llvm::createVirtRegRewriter() { -- 2.34.1