//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "spiller"
#include "Spiller.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/ADT/DepthFirstIterator.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/STLExtras.h"
-#include <algorithm>
+#include "llvm/CodeGen/LiveIntervalAnalysis.h"
+#include "llvm/CodeGen/LiveRangeEdit.h"
+#include "llvm/CodeGen/LiveStackAnalysis.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/VirtRegMap.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetInstrInfo.h"
+
using namespace llvm;
-STATISTIC(NumDSE , "Number of dead stores elided");
-STATISTIC(NumDSS , "Number of dead spill slots removed");
-STATISTIC(NumCommutes, "Number of instructions commuted");
-STATISTIC(NumDRM , "Number of re-materializable defs elided");
-STATISTIC(NumStores , "Number of stores added");
-STATISTIC(NumPSpills , "Number of physical register spills");
-STATISTIC(NumOmitted , "Number of reloads omited");
-STATISTIC(NumCopified, "Number of available reloads turned into copies");
-STATISTIC(NumReMats , "Number of re-materialization");
-STATISTIC(NumLoads , "Number of loads added");
-STATISTIC(NumReused , "Number of values reused");
-STATISTIC(NumDCE , "Number of copies elided");
-STATISTIC(NumSUnfold , "Number of stores unfolded");
-STATISTIC(NumModRefUnfold, "Number of modref unfolded");
+#define DEBUG_TYPE "spiller"
namespace {
- enum SpillerName { simple, local };
+ enum SpillerName { trivial, inline_ };
}
static cl::opt<SpillerName>
-SpillerOpt("spiller",
- cl::desc("Spiller to use: (default: local)"),
+spillerOpt("spiller",
+ cl::desc("Spiller to use: (default: standard)"),
cl::Prefix,
- cl::values(clEnumVal(simple, "simple spiller"),
- clEnumVal(local, "local spiller"),
+ cl::values(clEnumVal(trivial, "trivial spiller"),
+ clEnumValN(inline_, "inline", "inline spiller"),
clEnumValEnd),
- cl::init(local));
-
-// ****************************** //
-// Simple Spiller Implementation //
-// ****************************** //
+ cl::init(trivial));
+// Spiller virtual destructor implementation.
Spiller::~Spiller() {}
-bool SimpleSpiller::runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM) {
- DOUT << "********** REWRITE MACHINE CODE **********\n";
- DOUT << "********** Function: " << MF.getFunction()->getName() << '\n';
- const TargetMachine &TM = MF.getTarget();
- const TargetInstrInfo &TII = *TM.getInstrInfo();
- const TargetRegisterInfo &TRI = *TM.getRegisterInfo();
-
-
- // LoadedRegs - Keep track of which vregs are loaded, so that we only load
- // each vreg once (in the case where a spilled vreg is used by multiple
- // operands). This is always smaller than the number of operands to the
- // current machine instr, so it should be small.
- std::vector<unsigned> LoadedRegs;
-
- for (MachineFunction::iterator MBBI = MF.begin(), E = MF.end();
- MBBI != E; ++MBBI) {
- DOUT << MBBI->getBasicBlock()->getName() << ":\n";
- MachineBasicBlock &MBB = *MBBI;
- for (MachineBasicBlock::iterator MII = MBB.begin(), E = MBB.end();
- MII != E; ++MII) {
- MachineInstr &MI = *MII;
- for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI.getOperand(i);
- if (MO.isReg() && MO.getReg()) {
- if (TargetRegisterInfo::isVirtualRegister(MO.getReg())) {
- unsigned VirtReg = MO.getReg();
- unsigned SubIdx = MO.getSubReg();
- unsigned PhysReg = VRM.getPhys(VirtReg);
- unsigned RReg = SubIdx ? TRI.getSubReg(PhysReg, SubIdx) : PhysReg;
- if (!VRM.isAssignedReg(VirtReg)) {
- int StackSlot = VRM.getStackSlot(VirtReg);
- const TargetRegisterClass* RC =
- MF.getRegInfo().getRegClass(VirtReg);
-
- if (MO.isUse() &&
- std::find(LoadedRegs.begin(), LoadedRegs.end(), VirtReg)
- == LoadedRegs.end()) {
- TII.loadRegFromStackSlot(MBB, &MI, PhysReg, StackSlot, RC);
- MachineInstr *LoadMI = prior(MII);
- VRM.addSpillSlotUse(StackSlot, LoadMI);
- LoadedRegs.push_back(VirtReg);
- ++NumLoads;
- DOUT << '\t' << *LoadMI;
- }
-
- if (MO.isDef()) {
- TII.storeRegToStackSlot(MBB, next(MII), PhysReg, true,
- StackSlot, RC);
- MachineInstr *StoreMI = next(MII);
- VRM.addSpillSlotUse(StackSlot, StoreMI);
- ++NumStores;
- }
- }
- MF.getRegInfo().setPhysRegUsed(RReg);
- MI.getOperand(i).setReg(RReg);
- MI.getOperand(i).setSubReg(0);
- } else {
- MF.getRegInfo().setPhysRegUsed(MO.getReg());
- }
- }
- }
-
- DOUT << '\t' << MI;
- LoadedRegs.clear();
- }
- }
- return true;
-}
-
-// ****************** //
-// Utility Functions //
-// ****************** //
-
-/// InvalidateKill - A MI that defines the specified register is being deleted,
-/// invalidate the register kill information.
-static void InvalidateKill(unsigned Reg, BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps) {
- if (RegKills[Reg]) {
- KillOps[Reg]->setIsKill(false);
- KillOps[Reg] = NULL;
- RegKills.reset(Reg);
- }
-}
-
-/// findSinglePredSuccessor - Return via reference a vector of machine basic
-/// blocks each of which is a successor of the specified BB and has no other
-/// predecessor.
-static void findSinglePredSuccessor(MachineBasicBlock *MBB,
- SmallVectorImpl<MachineBasicBlock *> &Succs) {
- for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
- SE = MBB->succ_end(); SI != SE; ++SI) {
- MachineBasicBlock *SuccMBB = *SI;
- if (SuccMBB->pred_size() == 1)
- Succs.push_back(SuccMBB);
- }
-}
-
-/// InvalidateKills - MI is going to be deleted. If any of its operands are
-/// marked kill, then invalidate the information.
-static void InvalidateKills(MachineInstr &MI, BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps,
- SmallVector<unsigned, 2> *KillRegs = NULL) {
- for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI.getOperand(i);
- if (!MO.isReg() || !MO.isUse() || !MO.isKill())
- continue;
- unsigned Reg = MO.getReg();
- if (TargetRegisterInfo::isVirtualRegister(Reg))
- continue;
- if (KillRegs)
- KillRegs->push_back(Reg);
- assert(Reg < KillOps.size());
- if (KillOps[Reg] == &MO) {
- RegKills.reset(Reg);
- KillOps[Reg] = NULL;
- }
- }
-}
-
-/// InvalidateRegDef - If the def operand of the specified def MI is now dead
-/// (since it's spill instruction is removed), mark it isDead. Also checks if
-/// the def MI has other definition operands that are not dead. Returns it by
-/// reference.
-static bool InvalidateRegDef(MachineBasicBlock::iterator I,
- MachineInstr &NewDef, unsigned Reg,
- bool &HasLiveDef) {
- // 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.
- MachineInstr *DefMI = I;
- MachineOperand *DefOp = NULL;
- for (unsigned i = 0, e = DefMI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = DefMI->getOperand(i);
- if (MO.isReg() && MO.isDef()) {
- if (MO.getReg() == Reg)
- DefOp = &MO;
- else if (!MO.isDead())
- HasLiveDef = true;
- }
- }
- if (!DefOp)
- return false;
-
- bool FoundUse = false, Done = false;
- MachineBasicBlock::iterator E = &NewDef;
- ++I; ++E;
- for (; !Done && I != E; ++I) {
- MachineInstr *NMI = I;
- for (unsigned j = 0, ee = NMI->getNumOperands(); j != ee; ++j) {
- MachineOperand &MO = NMI->getOperand(j);
- if (!MO.isReg() || MO.getReg() != Reg)
- continue;
- if (MO.isUse())
- FoundUse = true;
- Done = true; // Stop after scanning all the operands of this MI.
- }
- }
- if (!FoundUse) {
- // Def is dead!
- DefOp->setIsDead();
- return true;
- }
- return false;
-}
-
-/// UpdateKills - Track and update kill info. If a MI reads a register that is
-/// marked kill, then it must be due to register reuse. Transfer the kill info
-/// over.
-static void UpdateKills(MachineInstr &MI, BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps,
- const TargetRegisterInfo* TRI) {
- for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI.getOperand(i);
- if (!MO.isReg() || !MO.isUse())
- continue;
- 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.
- KillOps[Reg]->setIsKill(false);
- KillOps[Reg] = NULL;
- RegKills.reset(Reg);
- if (!MI.isRegTiedToDefOperand(i))
- // Unless it's a two-address operand, this is the new kill.
- MO.setIsKill();
- }
- if (MO.isKill()) {
- RegKills.set(Reg);
- KillOps[Reg] = &MO;
- }
- }
-
- for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
- const MachineOperand &MO = MI.getOperand(i);
- if (!MO.isReg() || !MO.isDef())
- continue;
- unsigned Reg = MO.getReg();
- RegKills.reset(Reg);
- KillOps[Reg] = NULL;
- // It also defines (or partially define) aliases.
- for (const unsigned *AS = TRI->getAliasSet(Reg); *AS; ++AS) {
- RegKills.reset(*AS);
- KillOps[*AS] = NULL;
- }
- }
-}
-
-/// ReMaterialize - Re-materialize definition for Reg targetting DestReg.
-///
-static void ReMaterialize(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MII,
- unsigned DestReg, unsigned Reg,
- const TargetInstrInfo *TII,
- const TargetRegisterInfo *TRI,
- VirtRegMap &VRM) {
- TII->reMaterialize(MBB, MII, DestReg, VRM.getReMaterializedMI(Reg));
- MachineInstr *NewMI = prior(MII);
- for (unsigned i = 0, e = NewMI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = NewMI->getOperand(i);
- if (!MO.isReg() || MO.getReg() == 0)
- continue;
- unsigned VirtReg = MO.getReg();
- if (TargetRegisterInfo::isPhysicalRegister(VirtReg))
- continue;
- assert(MO.isUse());
- unsigned SubIdx = MO.getSubReg();
- unsigned Phys = VRM.getPhys(VirtReg);
- assert(Phys);
- unsigned RReg = SubIdx ? TRI->getSubReg(Phys, SubIdx) : Phys;
- MO.setReg(RReg);
- MO.setSubReg(0);
- }
- ++NumReMats;
-}
-
-/// findSuperReg - Find the SubReg's super-register of given register class
-/// where its SubIdx sub-register is SubReg.
-static unsigned findSuperReg(const TargetRegisterClass *RC, unsigned SubReg,
- unsigned SubIdx, const TargetRegisterInfo *TRI) {
- for (TargetRegisterClass::iterator I = RC->begin(), E = RC->end();
- I != E; ++I) {
- unsigned Reg = *I;
- if (TRI->getSubReg(Reg, SubIdx) == SubReg)
- return Reg;
- }
- return 0;
-}
-
-// ******************************** //
-// Available Spills Implementation //
-// ******************************** //
-
-/// disallowClobberPhysRegOnly - Unset the CanClobber bit of the specified
-/// stackslot register. The register is still available but is no longer
-/// allowed to be modifed.
-void AvailableSpills::disallowClobberPhysRegOnly(unsigned PhysReg) {
- std::multimap<unsigned, int>::iterator I =
- PhysRegsAvailable.lower_bound(PhysReg);
- while (I != PhysRegsAvailable.end() && I->first == PhysReg) {
- int SlotOrReMat = I->second;
- I++;
- assert((SpillSlotsOrReMatsAvailable[SlotOrReMat] >> 1) == PhysReg &&
- "Bidirectional map mismatch!");
- SpillSlotsOrReMatsAvailable[SlotOrReMat] &= ~1;
- DOUT << "PhysReg " << TRI->getName(PhysReg)
- << " copied, it is available for use but can no longer be modified\n";
- }
-}
-
-/// disallowClobberPhysReg - Unset the CanClobber bit of the specified
-/// stackslot register and its aliases. The register and its aliases may
-/// still available but is no longer allowed to be modifed.
-void AvailableSpills::disallowClobberPhysReg(unsigned PhysReg) {
- for (const unsigned *AS = TRI->getAliasSet(PhysReg); *AS; ++AS)
- disallowClobberPhysRegOnly(*AS);
- disallowClobberPhysRegOnly(PhysReg);
-}
-
-/// ClobberPhysRegOnly - This is called when the specified physreg changes
-/// value. We use this to invalidate any info about stuff we thing lives in it.
-void AvailableSpills::ClobberPhysRegOnly(unsigned PhysReg) {
- std::multimap<unsigned, int>::iterator I =
- PhysRegsAvailable.lower_bound(PhysReg);
- while (I != PhysRegsAvailable.end() && I->first == PhysReg) {
- int SlotOrReMat = I->second;
- PhysRegsAvailable.erase(I++);
- assert((SpillSlotsOrReMatsAvailable[SlotOrReMat] >> 1) == PhysReg &&
- "Bidirectional map mismatch!");
- SpillSlotsOrReMatsAvailable.erase(SlotOrReMat);
- DOUT << "PhysReg " << TRI->getName(PhysReg)
- << " clobbered, invalidating ";
- if (SlotOrReMat > VirtRegMap::MAX_STACK_SLOT)
- DOUT << "RM#" << SlotOrReMat-VirtRegMap::MAX_STACK_SLOT-1 << "\n";
- else
- DOUT << "SS#" << SlotOrReMat << "\n";
- }
-}
-
-/// ClobberPhysReg - This is called when the specified physreg changes
-/// value. We use this to invalidate any info about stuff we thing lives in
-/// it and any of its aliases.
-void AvailableSpills::ClobberPhysReg(unsigned PhysReg) {
- for (const unsigned *AS = TRI->getAliasSet(PhysReg); *AS; ++AS)
- ClobberPhysRegOnly(*AS);
- ClobberPhysRegOnly(PhysReg);
-}
-
-/// AddAvailableRegsToLiveIn - Availability information is being kept coming
-/// into the specified MBB. Add available physical registers as potential
-/// live-in's. If they are reused in the MBB, they will be added to the
-/// live-in set to make register scavenger and post-allocation scheduler.
-void AvailableSpills::AddAvailableRegsToLiveIn(MachineBasicBlock &MBB,
- BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps) {
- std::set<unsigned> NotAvailable;
- for (std::multimap<unsigned, int>::iterator
- I = PhysRegsAvailable.begin(), E = PhysRegsAvailable.end();
- I != E; ++I) {
- unsigned Reg = I->first;
- const TargetRegisterClass* RC = TRI->getPhysicalRegisterRegClass(Reg);
- // FIXME: A temporary workaround. We can't reuse available value if it's
- // not safe to move the def of the virtual register's class. e.g.
- // X86::RFP* register classes. Do not add it as a live-in.
- if (!TII->isSafeToMoveRegClassDefs(RC))
- // This is no longer available.
- NotAvailable.insert(Reg);
- else {
- MBB.addLiveIn(Reg);
- InvalidateKill(Reg, RegKills, KillOps);
- }
-
- // Skip over the same register.
- std::multimap<unsigned, int>::iterator NI = next(I);
- while (NI != E && NI->first == Reg) {
- ++I;
- ++NI;
- }
- }
-
- for (std::set<unsigned>::iterator I = NotAvailable.begin(),
- E = NotAvailable.end(); I != E; ++I) {
- ClobberPhysReg(*I);
- for (const unsigned *SubRegs = TRI->getSubRegisters(*I);
- *SubRegs; ++SubRegs)
- ClobberPhysReg(*SubRegs);
- }
-}
-
-/// ModifyStackSlotOrReMat - This method is called when the value in a stack
-/// slot changes. This removes information about which register the previous
-/// value for this slot lives in (as the previous value is dead now).
-void AvailableSpills::ModifyStackSlotOrReMat(int SlotOrReMat) {
- std::map<int, unsigned>::iterator It =
- SpillSlotsOrReMatsAvailable.find(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<unsigned, int>::iterator I = PhysRegsAvailable.lower_bound(Reg);
- for (; ; ++I) {
- assert(I != PhysRegsAvailable.end() && I->first == Reg &&
- "Map inverse broken!");
- if (I->second == SlotOrReMat) break;
- }
- PhysRegsAvailable.erase(I);
-}
-
-// ************************** //
-// Reuse Info Implementation //
-// ************************** //
-
-/// 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.
-unsigned ReuseInfo::GetRegForReload(unsigned PhysReg, MachineInstr *MI,
- AvailableSpills &Spills,
- std::vector<MachineInstr*> &MaybeDeadStores,
- SmallSet<unsigned, 8> &Rejected,
- BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps,
- VirtRegMap &VRM) {
- const TargetInstrInfo* TII = MI->getParent()->getParent()->getTarget()
- .getInstrInfo();
-
- if (Reuses.empty()) return PhysReg; // This is most often empty.
-
- for (unsigned ro = 0, e = Reuses.size(); ro != e; ++ro) {
- ReusedOp &Op = Reuses[ro];
- // If we find some other reuse that was supposed to use this register
- // exactly for its reload, we can change this reload to use ITS reload
- // register. That is, unless its reload register has already been
- // considered and subsequently rejected because it has also been reused
- // by another operand.
- if (Op.PhysRegReused == PhysReg &&
- Rejected.count(Op.AssignedPhysReg) == 0) {
- // Yup, use the reload register that we didn't use before.
- unsigned NewReg = Op.AssignedPhysReg;
- Rejected.insert(PhysReg);
- return GetRegForReload(NewReg, MI, Spills, MaybeDeadStores, Rejected,
- RegKills, KillOps, VRM);
- } 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.
- unsigned PRRU = Op.PhysRegReused;
- const TargetRegisterInfo *TRI = Spills.getRegInfo();
- if (TRI->areAliases(PRRU, PhysReg)) {
- // Okay, we found out that an alias of a reused register
- // was used. This isn't good because it means we have
- // to undo a previous reuse.
- MachineBasicBlock *MBB = MI->getParent();
- const TargetRegisterClass *AliasRC =
- MBB->getParent()->getRegInfo().getRegClass(Op.VirtReg);
-
- // Copy Op out of the vector and remove it, we're going to insert an
- // explicit load for it.
- ReusedOp NewOp = Op;
- Reuses.erase(Reuses.begin()+ro);
-
- // Ok, we're going to try to reload the assigned physreg into the
- // slot that we were supposed to in the first place. However, that
- // register could hold a reuse. Check to see if it conflicts or
- // would prefer us to use a different register.
- unsigned NewPhysReg = GetRegForReload(NewOp.AssignedPhysReg,
- MI, Spills, MaybeDeadStores,
- Rejected, RegKills, KillOps, VRM);
-
- MachineBasicBlock::iterator MII = MI;
- if (NewOp.StackSlotOrReMat > VirtRegMap::MAX_STACK_SLOT) {
- ReMaterialize(*MBB, MII, NewPhysReg, NewOp.VirtReg, TII, TRI,VRM);
- } else {
- TII->loadRegFromStackSlot(*MBB, MII, NewPhysReg,
- NewOp.StackSlotOrReMat, AliasRC);
- MachineInstr *LoadMI = prior(MII);
- VRM.addSpillSlotUse(NewOp.StackSlotOrReMat, LoadMI);
- // Any stores to this stack slot are not dead anymore.
- MaybeDeadStores[NewOp.StackSlotOrReMat] = NULL;
- ++NumLoads;
- }
- Spills.ClobberPhysReg(NewPhysReg);
- Spills.ClobberPhysReg(NewOp.PhysRegReused);
-
- unsigned SubIdx = MI->getOperand(NewOp.Operand).getSubReg();
- unsigned RReg = SubIdx ? TRI->getSubReg(NewPhysReg, SubIdx) : NewPhysReg;
- MI->getOperand(NewOp.Operand).setReg(RReg);
- MI->getOperand(NewOp.Operand).setSubReg(0);
+namespace {
- Spills.addAvailable(NewOp.StackSlotOrReMat, NewPhysReg);
- --MII;
- UpdateKills(*MII, RegKills, KillOps, TRI);
- DOUT << '\t' << *MII;
-
- DOUT << "Reuse undone!\n";
- --NumReused;
-
- // Finally, PhysReg is now available, go ahead and use it.
- return PhysReg;
+/// Utility class for spillers.
+class SpillerBase : public Spiller {
+protected:
+ MachineFunctionPass *pass;
+ MachineFunction *mf;
+ VirtRegMap *vrm;
+ LiveIntervals *lis;
+ MachineFrameInfo *mfi;
+ MachineRegisterInfo *mri;
+ const TargetInstrInfo *tii;
+ const TargetRegisterInfo *tri;
+
+ /// Construct a spiller base.
+ SpillerBase(MachineFunctionPass &pass, MachineFunction &mf, VirtRegMap &vrm)
+ : pass(&pass), mf(&mf), vrm(&vrm)
+ {
+ lis = &pass.getAnalysis<LiveIntervals>();
+ mfi = mf.getFrameInfo();
+ mri = &mf.getRegInfo();
+ tii = mf.getSubtarget().getInstrInfo();
+ tri = mf.getSubtarget().getRegisterInfo();
+ }
+
+ /// Add spill ranges for every use/def of the live interval, inserting loads
+ /// immediately before each use, and stores after each def. No folding or
+ /// remat is attempted.
+ void trivialSpillEverywhere(LiveRangeEdit& LRE) {
+ LiveInterval* li = &LRE.getParent();
+
+ DEBUG(dbgs() << "Spilling everywhere " << *li << "\n");
+
+ assert(li->weight != llvm::huge_valf &&
+ "Attempting to spill already spilled value.");
+
+ assert(!TargetRegisterInfo::isStackSlot(li->reg) &&
+ "Trying to spill a stack slot.");
+
+ DEBUG(dbgs() << "Trivial spill everywhere of reg" << li->reg << "\n");
+
+ const TargetRegisterClass *trc = mri->getRegClass(li->reg);
+ unsigned ss = vrm->assignVirt2StackSlot(li->reg);
+
+ // Iterate over reg uses/defs.
+ for (MachineRegisterInfo::reg_instr_iterator
+ regItr = mri->reg_instr_begin(li->reg);
+ regItr != mri->reg_instr_end();) {
+
+ // Grab the use/def instr.
+ MachineInstr *mi = &*regItr;
+
+ DEBUG(dbgs() << " Processing " << *mi);
+
+ // Step regItr to the next use/def instr.
+ ++regItr;
+
+ // Collect uses & defs for this instr.
+ SmallVector<unsigned, 2> indices;
+ bool hasUse = false;
+ bool hasDef = false;
+ for (unsigned i = 0; i != mi->getNumOperands(); ++i) {
+ MachineOperand &op = mi->getOperand(i);
+ if (!op.isReg() || op.getReg() != li->reg)
+ continue;
+ hasUse |= mi->getOperand(i).isUse();
+ hasDef |= mi->getOperand(i).isDef();
+ indices.push_back(i);
}
- }
- }
- return PhysReg;
-}
-
-// ***************************** //
-// Local Spiller Implementation //
-// ***************************** //
-bool LocalSpiller::runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM) {
- RegInfo = &MF.getRegInfo();
- TRI = MF.getTarget().getRegisterInfo();
- TII = MF.getTarget().getInstrInfo();
- AllocatableRegs = TRI->getAllocatableSet(MF);
- DOUT << "\n**** Local spiller rewriting function '"
- << MF.getFunction()->getName() << "':\n";
- DOUT << "**** Machine Instrs (NOTE! Does not include spills and reloads!)"
- " ****\n";
- DEBUG(MF.dump());
+ // Create a new virtual register for the load and/or store.
+ unsigned NewVReg = LRE.create();
- // 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<MachineOperand*> KillOps;
- KillOps.resize(TRI->getNumRegs(), NULL);
-
- // SingleEntrySuccs - Successor blocks which have a single predecessor.
- SmallVector<MachineBasicBlock*, 4> SinglePredSuccs;
- SmallPtrSet<MachineBasicBlock*,16> EarlyVisited;
-
- // Traverse the basic blocks depth first.
- MachineBasicBlock *Entry = MF.begin();
- SmallPtrSet<MachineBasicBlock*,16> Visited;
- for (df_ext_iterator<MachineBasicBlock*,
- SmallPtrSet<MachineBasicBlock*,16> >
- 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, 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, Spills, RegKills, KillOps);
+ // Update the reg operands & kill flags.
+ for (unsigned i = 0; i < indices.size(); ++i) {
+ unsigned mopIdx = indices[i];
+ MachineOperand &mop = mi->getOperand(mopIdx);
+ mop.setReg(NewVReg);
+ if (mop.isUse() && !mi->isRegTiedToDefOperand(mopIdx)) {
+ mop.setIsKill(true);
}
}
- } while (MBB);
+ assert(hasUse || hasDef);
- // Clear the availability info.
- Spills.clear();
- }
-
- DOUT << "**** Post Machine Instrs ****\n";
- DEBUG(MF.dump());
+ // Insert reload if necessary.
+ MachineBasicBlock::iterator miItr(mi);
+ if (hasUse) {
+ MachineInstrSpan MIS(miItr);
- // 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;
+ tii->loadRegFromStackSlot(*mi->getParent(), miItr, NewVReg, ss, trc,
+ tri);
+ lis->InsertMachineInstrRangeInMaps(MIS.begin(), miItr);
}
- return true;
-}
-
+ // Insert store if necessary.
+ if (hasDef) {
+ MachineInstrSpan MIS(miItr);
-/// FoldsStackSlotModRef - Return true if the specified MI folds the specified
-/// stack slot mod/ref. It also checks if it's possible to unfold the
-/// instruction by having it define a specified physical register instead.
-static bool FoldsStackSlotModRef(MachineInstr &MI, int SS, unsigned PhysReg,
- const TargetInstrInfo *TII,
- const TargetRegisterInfo *TRI,
- VirtRegMap &VRM) {
- if (VRM.hasEmergencySpills(&MI) || VRM.isSpillPt(&MI))
- return false;
-
- bool Found = false;
- VirtRegMap::MI2VirtMapTy::const_iterator I, End;
- for (tie(I, End) = VRM.getFoldedVirts(&MI); I != End; ++I) {
- unsigned VirtReg = I->second.first;
- VirtRegMap::ModRef MR = I->second.second;
- if (MR & VirtRegMap::isModRef)
- if (VRM.getStackSlot(VirtReg) == SS) {
- Found= TII->getOpcodeAfterMemoryUnfold(MI.getOpcode(), true, true) != 0;
- break;
+ tii->storeRegToStackSlot(*mi->getParent(), std::next(miItr), NewVReg,
+ true, ss, trc, tri);
+ lis->InsertMachineInstrRangeInMaps(std::next(miItr), MIS.end());
}
- }
- if (!Found)
- return false;
-
- // Does the instruction uses a register that overlaps the scratch register?
- for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI.getOperand(i);
- if (!MO.isReg() || MO.getReg() == 0)
- continue;
- unsigned Reg = MO.getReg();
- if (TargetRegisterInfo::isVirtualRegister(Reg)) {
- if (!VRM.hasPhys(Reg))
- continue;
- Reg = VRM.getPhys(Reg);
}
- if (TRI->regsOverlap(PhysReg, Reg))
- return false;
}
- return true;
-}
+};
-/// FindFreeRegister - Find a free register of a given register class by looking
-/// at (at most) the last two machine instructions.
-static unsigned FindFreeRegister(MachineBasicBlock::iterator MII,
- MachineBasicBlock &MBB,
- const TargetRegisterClass *RC,
- const TargetRegisterInfo *TRI,
- BitVector &AllocatableRegs) {
- BitVector Defs(TRI->getNumRegs());
- BitVector Uses(TRI->getNumRegs());
- SmallVector<unsigned, 4> LocalUses;
- SmallVector<unsigned, 4> Kills;
+} // end anonymous namespace
- // Take a look at 2 instructions at most.
- for (unsigned Count = 0; Count < 2; ++Count) {
- if (MII == MBB.begin())
- break;
- MachineInstr *PrevMI = prior(MII);
- for (unsigned i = 0, e = PrevMI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = PrevMI->getOperand(i);
- if (!MO.isReg() || MO.getReg() == 0)
- continue;
- unsigned Reg = MO.getReg();
- if (MO.isDef()) {
- Defs.set(Reg);
- for (const unsigned *AS = TRI->getAliasSet(Reg); *AS; ++AS)
- Defs.set(*AS);
- } else {
- LocalUses.push_back(Reg);
- if (MO.isKill() && AllocatableRegs[Reg])
- Kills.push_back(Reg);
- }
- }
-
- for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
- unsigned Kill = Kills[i];
- if (!Defs[Kill] && !Uses[Kill] &&
- TRI->getPhysicalRegisterRegClass(Kill) == RC)
- return Kill;
- }
- for (unsigned i = 0, e = LocalUses.size(); i != e; ++i) {
- unsigned Reg = LocalUses[i];
- Uses.set(Reg);
- for (const unsigned *AS = TRI->getAliasSet(Reg); *AS; ++AS)
- Uses.set(*AS);
- }
-
- MII = PrevMI;
- }
-
- return 0;
-}
-
-static
-void AssignPhysToVirtReg(MachineInstr *MI, unsigned VirtReg, unsigned PhysReg) {
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI->getOperand(i);
- if (MO.isReg() && MO.getReg() == VirtReg)
- MO.setReg(PhysReg);
- }
-}
-
-/// OptimizeByUnfold2 - Unfold a series of load / store folding instructions if
-/// a scratch register is available.
-/// xorq %r12<kill>, %r13
-/// addq %rax, -184(%rbp)
-/// addq %r13, -184(%rbp)
-/// ==>
-/// xorq %r12<kill>, %r13
-/// movq -184(%rbp), %r12
-/// addq %rax, %r12
-/// addq %r13, %r12
-/// movq %r12, -184(%rbp)
-bool LocalSpiller::OptimizeByUnfold2(unsigned VirtReg, int SS,
- MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MII,
- std::vector<MachineInstr*> &MaybeDeadStores,
- AvailableSpills &Spills,
- BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps,
- VirtRegMap &VRM) {
- MachineBasicBlock::iterator NextMII = 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 = RegInfo->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;
-
- // 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<MachineInstr*, 4> NewMIs;
- if (!TII->unfoldMemoryOperand(MF, &MI, VirtReg, false, false, NewMIs))
- assert(0 && "Unable unfold the load / store folding instruction!");
- assert(NewMIs.size() == 1);
- AssignPhysToVirtReg(NewMIs[0], VirtReg, PhysReg);
- VRM.transferRestorePts(&MI, NewMIs[0]);
- MII = MBB.insert(MII, NewMIs[0]);
- InvalidateKills(MI, RegKills, KillOps);
- VRM.RemoveMachineInstrFromMaps(&MI);
- MBB.erase(&MI);
- ++NumModRefUnfold;
-
- // Unfold next instructions that fold the same SS.
- do {
- MachineInstr &NextMI = *NextMII;
- NextMII = next(NextMII);
- NewMIs.clear();
- if (!TII->unfoldMemoryOperand(MF, &NextMI, VirtReg, false, false, NewMIs))
- assert(0 && "Unable unfold the load / store folding instruction!");
- assert(NewMIs.size() == 1);
- AssignPhysToVirtReg(NewMIs[0], VirtReg, PhysReg);
- VRM.transferRestorePts(&NextMI, NewMIs[0]);
- MBB.insert(NextMII, NewMIs[0]);
- InvalidateKills(NextMI, RegKills, KillOps);
- VRM.RemoveMachineInstrFromMaps(&NextMI);
- MBB.erase(&NextMI);
- ++NumModRefUnfold;
- } 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);
-
- 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 LocalSpiller::OptimizeByUnfold(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MII,
- std::vector<MachineInstr*> &MaybeDeadStores,
- AvailableSpills &Spills,
- BitVector &RegKills,
- std::vector<MachineOperand*> &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))
- 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);
- }
- }
-
- if (!UnfoldedOpc) {
- if (!UnfoldVR)
- return false;
-
- // Look for other unfolding opportunities.
- return OptimizeByUnfold2(UnfoldVR, FoldedSS, MBB, MII,
- MaybeDeadStores, Spills, RegKills, KillOps, VRM);
- }
-
- 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;
- }
-
- // 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<MachineInstr*, 4> 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<unsigned, 1> 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, RegKills, KillOps);
- VRM.RemoveMachineInstrFromMaps(&MI);
- MBB.erase(&MI);
- MF.DeleteMachineInstr(NewMI);
- return true;
- }
- MF.DeleteMachineInstr(NewMI);
- }
- }
-
- return false;
-}
-
-/// CommuteToFoldReload -
-/// Look for
-/// r1 = load fi#1
-/// r1 = op r1, r2<kill>
-/// 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 LocalSpiller::CommuteToFoldReload(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MII,
- unsigned VirtReg, unsigned SrcReg, int SS,
- AvailableSpills &Spills,
- BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps,
- const TargetRegisterInfo *TRI,
- VirtRegMap &VRM) {
- 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() &&
- TII->CommuteChangesDestination(DefMI, 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<unsigned, 1> 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, RegKills, KillOps);
- VRM.RemoveMachineInstrFromMaps(ReloadMI);
- MBB.erase(ReloadMI);
- InvalidateKills(*DefMI, RegKills, KillOps);
- VRM.RemoveMachineInstrFromMaps(DefMI);
- MBB.erase(DefMI);
- InvalidateKills(MI, 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);
-
- ++NumCommutes;
- return true;
- }
-
- return false;
-}
-
-/// 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 LocalSpiller::SpillRegToStackSlot(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MII,
- int Idx, unsigned PhysReg, int StackSlot,
- const TargetRegisterClass *RC,
- bool isAvailable, MachineInstr *&LastStore,
- AvailableSpills &Spills,
- SmallSet<MachineInstr*, 4> &ReMatDefs,
- BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps,
- VirtRegMap &VRM) {
- TII->storeRegToStackSlot(MBB, next(MII), PhysReg, true, StackSlot, RC);
- MachineInstr *StoreMI = next(MII);
- VRM.addSpillSlotUse(StackSlot, StoreMI);
- DOUT << "Store:\t" << *StoreMI;
-
- // If there is a dead store to this stack slot, nuke it now.
- if (LastStore) {
- DOUT << "Removed dead store:\t" << *LastStore;
- ++NumDSE;
- SmallVector<unsigned, 2> KillRegs;
- InvalidateKills(*LastStore, 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)) {
- 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;
- }
- }
- }
- }
- }
-
- LastStore = next(MII);
+namespace {
- // 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;
-}
+/// Spills any live range using the spill-everywhere method with no attempt at
+/// folding.
+class TrivialSpiller : public SpillerBase {
+public:
-/// 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 LocalSpiller::TransferDeadness(MachineBasicBlock *MBB, unsigned CurDist,
- unsigned Reg, BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps) {
- int LastUDDist = -1;
- MachineInstr *LastUDMI = NULL;
- 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<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(UDMI);
- if (DI == DistanceMap.end() || DI->second > CurDist)
- continue;
- if ((int)DI->second < LastUDDist)
- continue;
- LastUDDist = DI->second;
- LastUDMI = UDMI;
- }
+ TrivialSpiller(MachineFunctionPass &pass, MachineFunction &mf,
+ VirtRegMap &vrm)
+ : SpillerBase(pass, mf, vrm) {}
- if (LastUDMI) {
- 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))
- return;
- }
- if (LastUD->isDef())
- LastUD->setIsDead();
- else {
- LastUD->setIsKill();
- RegKills.set(Reg);
- KillOps[Reg] = LastUD;
- }
+ void spill(LiveRangeEdit &LRE) override {
+ // Ignore spillIs - we don't use it.
+ trivialSpillEverywhere(LRE);
}
-}
+};
-/// rewriteMBB - Keep track of which spills are available even after the
-/// register allocator is done with them. If possible, avid reloading vregs.
-void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM,
- AvailableSpills &Spills, BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps) {
- DOUT << "\n**** Local spiller rewriting MBB '"
- << MBB.getBasicBlock()->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<MachineInstr*> MaybeDeadStores;
- MaybeDeadStores.resize(MF.getFrameInfo()->getObjectIndexEnd(), NULL);
-
- // ReMatDefs - These are rematerializable def MIs which are not deleted.
- SmallSet<MachineInstr*, 4> ReMatDefs;
-
- // Clear kill info.
- SmallSet<unsigned, 2> 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 = next(MII);
-
- VirtRegMap::MI2VirtMapTy::const_iterator I, End;
- bool Erased = false;
- bool BackTracked = false;
- if (OptimizeByUnfold(MBB, MII,
- MaybeDeadStores, Spills, RegKills, KillOps, VRM))
- NextMII = 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<int, 4> UsedSS;
- std::vector<unsigned> &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))
- assert(0 && "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, next(MII), PhysReg, SS, RC);
- MachineInstr *LoadMI = next(MII);
- VRM.addSpillSlotUse(SS, LoadMI);
- ++NumPSpills;
- }
- NextMII = next(MII);
- }
-
- // Insert restores here if asked to.
- if (VRM.isRestorePt(&MI)) {
- std::vector<unsigned> &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<kill>
- // ... # 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)
- DOUT << "Reusing RM#" << SSorRMId-VirtRegMap::MAX_STACK_SLOT-1;
- else
- DOUT << "Reusing SS#" << SSorRMId;
- DOUT << " 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)
- DOUT << "Reusing RM#" << SSorRMId-VirtRegMap::MAX_STACK_SLOT-1;
- else
- DOUT << "Reusing SS#" << SSorRMId;
- DOUT << " 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.
- TII->copyRegToReg(MBB, &MI, Phys, InReg, RC, RC);
-
- // This invalidates Phys.
- Spills.ClobberPhysReg(Phys);
- // Remember it's available.
- Spills.addAvailable(SSorRMId, Phys);
-
- // Mark is killed.
- MachineInstr *CopyMI = prior(MII);
- MachineOperand *KillOpnd = CopyMI->findRegisterUseOperand(InReg);
- KillOpnd->setIsKill();
- UpdateKills(*CopyMI, RegKills, KillOps, TRI);
-
- DOUT << '\t' << *CopyMI;
- ++NumCopified;
- continue;
- }
-
- if (VRM.isReMaterialized(VirtReg)) {
- ReMaterialize(MBB, MII, Phys, VirtReg, TII, TRI, VRM);
- } else {
- const TargetRegisterClass* RC = RegInfo->getRegClass(VirtReg);
- TII->loadRegFromStackSlot(MBB, &MI, Phys, SSorRMId, RC);
- MachineInstr *LoadMI = prior(MII);
- VRM.addSpillSlotUse(SSorRMId, LoadMI);
- ++NumLoads;
- }
-
- // This invalidates Phys.
- Spills.ClobberPhysReg(Phys);
- // Remember it's available.
- Spills.addAvailable(SSorRMId, Phys);
-
- UpdateKills(*prior(MII), RegKills, KillOps, TRI);
- DOUT << '\t' << *prior(MII);
- }
- }
-
- // Insert spills here if asked to.
- if (VRM.isSpillPt(&MI)) {
- std::vector<std::pair<unsigned,bool> > &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);
- TII->storeRegToStackSlot(MBB, next(MII), Phys, isKill, StackSlot, RC);
- MachineInstr *StoreMI = next(MII);
- VRM.addSpillSlotUse(StackSlot, StoreMI);
- DOUT << "Store:\t" << *StoreMI;
- VRM.virtFolded(VirtReg, StoreMI, VirtRegMap::isMod);
- }
- NextMII = next(MII);
- }
-
- /// ReusedOperands - Keep track of operand reuse in case we need to undo
- /// reuse.
- ReuseInfo ReusedOperands(MI, TRI);
- SmallVector<unsigned, 4> 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);
- 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".
- VirtUseOps.insert(VirtUseOps.begin(), i);
- else
- VirtUseOps.push_back(i);
- }
-
- // Process all of the spilled uses and all non spilled reg references.
- SmallVector<int, 2> PotentialDeadStoreSlots;
- KilledMIRegs.clear();
- for (unsigned j = 0, e = VirtUseOps.size(); j != e; ++j) {
- unsigned i = VirtUseOps[j];
- MachineOperand &MO = MI.getOperand(i);
- unsigned VirtReg = MO.getReg();
- assert(TargetRegisterInfo::isVirtualRegister(VirtReg) &&
- "Not a virtual register?");
-
- unsigned SubIdx = MO.getSubReg();
- if (VRM.isAssignedReg(VirtReg)) {
- // This virtual register was assigned a physreg!
- unsigned Phys = VRM.getPhys(VirtReg);
- RegInfo->setPhysRegUsed(Phys);
- if (MO.isDef())
- ReusedOperands.markClobbered(Phys);
- unsigned RReg = SubIdx ? TRI->getSubReg(Phys, SubIdx) : Phys;
- MI.getOperand(i).setReg(RReg);
- MI.getOperand(i).setSubReg(0);
- if (VRM.isImplicitlyDefined(VirtReg))
- BuildMI(MBB, &MI, MI.getDebugLoc(),
- TII->get(TargetInstrInfo::IMPLICIT_DEF), RReg);
- continue;
- }
-
- // This virtual register is now known to be a spilled value.
- if (!MO.isUse())
- continue; // Handle defs in the loop below (handle use&def here though)
-
- 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 &&
- (SubIdx || MI.getOpcode() == TargetInstrInfo::EXTRACT_SUBREG)) {
- const TargetRegisterClass* RC = RegInfo->getRegClass(VirtReg);
- if (!RC->contains(PhysReg))
- PhysReg = 0;
- }
-
- if (PhysReg) {
- // 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)
- DOUT << "Reusing RM#" << ReuseSlot-VirtRegMap::MAX_STACK_SLOT-1;
- else
- DOUT << "Reusing SS#" << ReuseSlot;
- DOUT << " 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);
+} // end anonymous namespace
- // 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;
- } // 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(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)
- DOUT << "Reusing RM#" << ReuseSlot-VirtRegMap::MAX_STACK_SLOT-1;
- else
- DOUT << "Reusing SS#" << ReuseSlot;
- DOUT << " 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);
- TII->copyRegToReg(MBB, &MI, DesignatedReg, PhysReg, RC, RC);
-
- MachineInstr *CopyMI = prior(MII);
- UpdateKills(*CopyMI, RegKills, KillOps, TRI);
-
- // 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);
- DOUT << '\t' << *prior(MII);
- ++NumReused;
- continue;
- } // if (PhysReg)
-
- // 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(PhysReg, &MI,
- Spills, MaybeDeadStores, RegKills, KillOps, VRM);
-
- RegInfo->setPhysRegUsed(PhysReg);
- ReusedOperands.markClobbered(PhysReg);
- if (DoReMat) {
- ReMaterialize(MBB, MII, PhysReg, VirtReg, TII, TRI, VRM);
- } else {
- const TargetRegisterClass* RC = RegInfo->getRegClass(VirtReg);
- TII->loadRegFromStackSlot(MBB, &MI, PhysReg, SSorRMId, RC);
- MachineInstr *LoadMI = prior(MII);
- VRM.addSpillSlotUse(SSorRMId, LoadMI);
- ++NumLoads;
- }
- // 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);
- }
- unsigned RReg = SubIdx ? TRI->getSubReg(PhysReg, SubIdx) : PhysReg;
- MI.getOperand(i).setReg(RReg);
- MI.getOperand(i).setSubReg(0);
- UpdateKills(*prior(MII), RegKills, KillOps, TRI);
- DOUT << '\t' << *prior(MII);
- }
-
- // 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) {
- DOUT << "Removed dead store:\t" << *DeadStore;
- InvalidateKills(*DeadStore, RegKills, KillOps);
- VRM.RemoveMachineInstrFromMaps(DeadStore);
- MBB.erase(DeadStore);
- MaybeDeadStores[PDSSlot] = NULL;
- ++NumDSE;
- }
- }
-
-
- DOUT << '\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<int, 2> FoldedSS;
- for (tie(I, End) = VRM.getFoldedVirts(&MI); I != End; ) {
- unsigned VirtReg = I->second.first;
- VirtRegMap::ModRef MR = I->second.second;
- DOUT << "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);
- DOUT << " - 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)) {
- DOUT << "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.
- // 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 {
- DOUT << "Removing now-noop copy: " << MI;
- // Unset last kill since it's being reused.
- InvalidateKill(InReg, RegKills, KillOps);
- Spills.disallowClobberPhysReg(InReg);
- }
-
- InvalidateKills(MI, RegKills, KillOps);
- VRM.RemoveMachineInstrFromMaps(&MI);
- MBB.erase(&MI);
- Erased = true;
- goto ProcessNextInst;
- }
- } else {
- unsigned PhysReg = Spills.getSpillSlotOrReMatPhysReg(SS);
- SmallVector<MachineInstr*, 4> NewMIs;
- if (PhysReg &&
- TII->unfoldMemoryOperand(MF, &MI, PhysReg, false, false, NewMIs)) {
- MBB.insert(MII, NewMIs[0]);
- InvalidateKills(MI, 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<MachineInstr*, 4> 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, 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.
- DOUT << "Removed dead store:\t" << *DeadStore;
- InvalidateKills(*DeadStore, 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(MBB, MII, VirtReg, SrcReg, StackSlot,
- Spills, RegKills, KillOps, TRI, VRM)) {
- NextMII = next(MII);
- BackTracked = true;
- 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;
-
- // 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));
- }
- }
- }
- }
-
- // 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.
- unsigned Src, Dst, SrcSR, DstSR;
- if (TII->isMoveInstr(MI, Src, Dst, SrcSR, DstSR) && Src == Dst) {
- ++NumDCE;
- DOUT << "Removing now-noop copy: " << MI;
- SmallVector<unsigned, 2> KillRegs;
- InvalidateKills(MI, 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.RemoveMachineInstrFromMaps(&MI);
- MBB.erase(&MI);
- Erased = true;
- Spills.disallowClobberPhysReg(VirtReg);
- 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(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 = 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;
- DOUT << "Removing now-noop copy: " << MI;
- InvalidateKills(MI, RegKills, KillOps);
- VRM.RemoveMachineInstrFromMaps(&MI);
- MBB.erase(&MI);
- Erased = true;
- UpdateKills(*LastStore, RegKills, KillOps, TRI);
- goto ProcessNextInst;
- }
- }
- }
- }
- ProcessNextInst:
- DistanceMap.insert(std::make_pair(&MI, Dist++));
- if (!Erased && !BackTracked) {
- for (MachineBasicBlock::iterator II = &MI; II != NextMII; ++II)
- UpdateKills(*II, RegKills, KillOps, TRI);
- }
- MII = NextMII;
- }
-
-}
+void Spiller::anchor() { }
-llvm::Spiller* llvm::createSpiller() {
- switch (SpillerOpt) {
- default: assert(0 && "Unreachable!");
- case local:
- return new LocalSpiller();
- case simple:
- return new SimpleSpiller();
+llvm::Spiller* llvm::createSpiller(MachineFunctionPass &pass,
+ MachineFunction &mf,
+ VirtRegMap &vrm) {
+ switch (spillerOpt) {
+ case trivial: return new TrivialSpiller(pass, mf, vrm);
+ case inline_: return createInlineSpiller(pass, mf, vrm);
}
+ llvm_unreachable("Invalid spiller optimization");
}
projects / oota-llvm.git / blobdiff