//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the VirtRegMap class.
//
-// It also contains implementations of the the Spiller interface, which, given a
+// It also contains implementations of the Spiller interface, which, given a
// virtual register map and a machine function, eliminates all virtual
// references by replacing them with physical register references - adding spill
// code as necessary.
//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "spiller"
+#define DEBUG_TYPE "virtregmap"
#include "VirtRegMap.h"
#include "llvm/Function.h"
+#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/SSARegMap.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Debug.h"
#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallSet.h"
#include <algorithm>
using namespace llvm;
-STATISTIC(NumSpills, "Number of register spills");
-STATISTIC(NumReMats, "Number of re-materialization");
-STATISTIC(NumStores, "Number of stores added");
-STATISTIC(NumLoads , "Number of loads added");
-STATISTIC(NumReused, "Number of values reused");
-STATISTIC(NumDSE , "Number of dead stores elided");
-STATISTIC(NumDCE , "Number of copies elided");
-
-namespace {
- enum SpillerName { simple, local };
-
- static cl::opt<SpillerName>
- SpillerOpt("spiller",
- cl::desc("Spiller to use: (default: local)"),
- cl::Prefix,
- cl::values(clEnumVal(simple, " simple spiller"),
- clEnumVal(local, " local spiller"),
- clEnumValEnd),
- cl::init(local));
-}
+STATISTIC(NumSpills , "Number of register spills");
//===----------------------------------------------------------------------===//
// VirtRegMap implementation
//===----------------------------------------------------------------------===//
-VirtRegMap::VirtRegMap(MachineFunction &mf)
- : TII(*mf.getTarget().getInstrInfo()), MF(mf),
- Virt2PhysMap(NO_PHYS_REG), Virt2StackSlotMap(NO_STACK_SLOT),
- ReMatId(MAX_STACK_SLOT+1) {
+char VirtRegMap::ID = 0;
+
+static RegisterPass<VirtRegMap>
+X("virtregmap", "Virtual Register Map");
+
+bool VirtRegMap::runOnMachineFunction(MachineFunction &mf) {
+ MRI = &mf.getRegInfo();
+ TII = mf.getTarget().getInstrInfo();
+ TRI = mf.getTarget().getRegisterInfo();
+ MF = &mf;
+
+ ReMatId = MAX_STACK_SLOT+1;
+ LowSpillSlot = HighSpillSlot = NO_STACK_SLOT;
+
+ Virt2PhysMap.clear();
+ Virt2StackSlotMap.clear();
+ Virt2ReMatIdMap.clear();
+ Virt2SplitMap.clear();
+ Virt2SplitKillMap.clear();
+ ReMatMap.clear();
+ ImplicitDefed.clear();
+ SpillSlotToUsesMap.clear();
+ MI2VirtMap.clear();
+ SpillPt2VirtMap.clear();
+ RestorePt2VirtMap.clear();
+ EmergencySpillMap.clear();
+ EmergencySpillSlots.clear();
+
+ SpillSlotToUsesMap.resize(8);
+ ImplicitDefed.resize(MF->getRegInfo().getLastVirtReg()+1-
+ TargetRegisterInfo::FirstVirtualRegister);
+
+ allocatableRCRegs.clear();
+ for (TargetRegisterInfo::regclass_iterator I = TRI->regclass_begin(),
+ E = TRI->regclass_end(); I != E; ++I)
+ allocatableRCRegs.insert(std::make_pair(*I,
+ TRI->getAllocatableSet(mf, *I)));
+
grow();
+
+ return false;
}
void VirtRegMap::grow() {
- Virt2PhysMap.grow(MF.getSSARegMap()->getLastVirtReg());
- Virt2StackSlotMap.grow(MF.getSSARegMap()->getLastVirtReg());
+ unsigned LastVirtReg = MF->getRegInfo().getLastVirtReg();
+ Virt2PhysMap.grow(LastVirtReg);
+ Virt2StackSlotMap.grow(LastVirtReg);
+ Virt2ReMatIdMap.grow(LastVirtReg);
+ Virt2SplitMap.grow(LastVirtReg);
+ Virt2SplitKillMap.grow(LastVirtReg);
+ ReMatMap.grow(LastVirtReg);
+ ImplicitDefed.resize(LastVirtReg-TargetRegisterInfo::FirstVirtualRegister+1);
+}
+
+unsigned VirtRegMap::getRegAllocPref(unsigned virtReg) {
+ std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(virtReg);
+ unsigned physReg = Hint.second;
+ if (physReg &&
+ TargetRegisterInfo::isVirtualRegister(physReg) && hasPhys(physReg))
+ physReg = getPhys(physReg);
+ if (Hint.first == 0)
+ return (physReg && TargetRegisterInfo::isPhysicalRegister(physReg))
+ ? physReg : 0;
+ return TRI->ResolveRegAllocHint(Hint.first, physReg, *MF);
}
int VirtRegMap::assignVirt2StackSlot(unsigned virtReg) {
- assert(MRegisterInfo::isVirtualRegister(virtReg));
+ assert(TargetRegisterInfo::isVirtualRegister(virtReg));
assert(Virt2StackSlotMap[virtReg] == NO_STACK_SLOT &&
"attempt to assign stack slot to already spilled register");
- const TargetRegisterClass* RC = MF.getSSARegMap()->getRegClass(virtReg);
- int frameIndex = MF.getFrameInfo()->CreateStackObject(RC->getSize(),
- RC->getAlignment());
- Virt2StackSlotMap[virtReg] = frameIndex;
+ const TargetRegisterClass* RC = MF->getRegInfo().getRegClass(virtReg);
+ int SS = MF->getFrameInfo()->CreateSpillStackObject(RC->getSize(),
+ RC->getAlignment());
+ if (LowSpillSlot == NO_STACK_SLOT)
+ LowSpillSlot = SS;
+ if (HighSpillSlot == NO_STACK_SLOT || SS > HighSpillSlot)
+ HighSpillSlot = SS;
+ unsigned Idx = SS-LowSpillSlot;
+ while (Idx >= SpillSlotToUsesMap.size())
+ SpillSlotToUsesMap.resize(SpillSlotToUsesMap.size()*2);
+ Virt2StackSlotMap[virtReg] = SS;
++NumSpills;
- return frameIndex;
+ return SS;
}
-void VirtRegMap::assignVirt2StackSlot(unsigned virtReg, int frameIndex) {
- assert(MRegisterInfo::isVirtualRegister(virtReg));
+void VirtRegMap::assignVirt2StackSlot(unsigned virtReg, int SS) {
+ assert(TargetRegisterInfo::isVirtualRegister(virtReg));
assert(Virt2StackSlotMap[virtReg] == NO_STACK_SLOT &&
"attempt to assign stack slot to already spilled register");
- assert((frameIndex >= 0 ||
- (frameIndex >= MF.getFrameInfo()->getObjectIndexBegin())) &&
+ assert((SS >= 0 ||
+ (SS >= MF->getFrameInfo()->getObjectIndexBegin())) &&
"illegal fixed frame index");
- Virt2StackSlotMap[virtReg] = frameIndex;
+ Virt2StackSlotMap[virtReg] = SS;
}
int VirtRegMap::assignVirtReMatId(unsigned virtReg) {
- assert(MRegisterInfo::isVirtualRegister(virtReg));
- assert(Virt2StackSlotMap[virtReg] == NO_STACK_SLOT &&
+ assert(TargetRegisterInfo::isVirtualRegister(virtReg));
+ assert(Virt2ReMatIdMap[virtReg] == NO_STACK_SLOT &&
"attempt to assign re-mat id to already spilled register");
- const MachineInstr *DefMI = getReMaterializedMI(virtReg);
- int FrameIdx;
- if (TII.isLoadFromStackSlot((MachineInstr*)DefMI, FrameIdx)) {
- // Load from stack slot is re-materialize as reload from the stack slot!
- Virt2StackSlotMap[virtReg] = FrameIdx;
- return FrameIdx;
- }
- Virt2StackSlotMap[virtReg] = ReMatId;
+ Virt2ReMatIdMap[virtReg] = ReMatId;
return ReMatId++;
}
+void VirtRegMap::assignVirtReMatId(unsigned virtReg, int id) {
+ assert(TargetRegisterInfo::isVirtualRegister(virtReg));
+ assert(Virt2ReMatIdMap[virtReg] == NO_STACK_SLOT &&
+ "attempt to assign re-mat id to already spilled register");
+ Virt2ReMatIdMap[virtReg] = id;
+}
+
+int VirtRegMap::getEmergencySpillSlot(const TargetRegisterClass *RC) {
+ std::map<const TargetRegisterClass*, int>::iterator I =
+ EmergencySpillSlots.find(RC);
+ if (I != EmergencySpillSlots.end())
+ return I->second;
+ int SS = MF->getFrameInfo()->CreateSpillStackObject(RC->getSize(),
+ RC->getAlignment());
+ if (LowSpillSlot == NO_STACK_SLOT)
+ LowSpillSlot = SS;
+ if (HighSpillSlot == NO_STACK_SLOT || SS > HighSpillSlot)
+ HighSpillSlot = SS;
+ EmergencySpillSlots[RC] = SS;
+ return SS;
+}
+
+void VirtRegMap::addSpillSlotUse(int FI, MachineInstr *MI) {
+ if (!MF->getFrameInfo()->isFixedObjectIndex(FI)) {
+ // If FI < LowSpillSlot, this stack reference was produced by
+ // instruction selection and is not a spill
+ if (FI >= LowSpillSlot) {
+ assert(FI >= 0 && "Spill slot index should not be negative!");
+ assert((unsigned)FI-LowSpillSlot < SpillSlotToUsesMap.size()
+ && "Invalid spill slot");
+ SpillSlotToUsesMap[FI-LowSpillSlot].insert(MI);
+ }
+ }
+}
+
void VirtRegMap::virtFolded(unsigned VirtReg, MachineInstr *OldMI,
- unsigned OpNo, MachineInstr *NewMI) {
+ MachineInstr *NewMI, ModRef MRInfo) {
// Move previous memory references folded to new instruction.
MI2VirtMapTy::iterator IP = MI2VirtMap.lower_bound(NewMI);
for (MI2VirtMapTy::iterator I = MI2VirtMap.lower_bound(OldMI),
MI2VirtMap.erase(I++);
}
- ModRef MRInfo;
- const TargetInstrDescriptor *TID = OldMI->getInstrDescriptor();
- if (TID->getOperandConstraint(OpNo, TOI::TIED_TO) != -1 ||
- TID->findTiedToSrcOperand(OpNo) != -1) {
- // Folded a two-address operand.
- MRInfo = isModRef;
- } else if (OldMI->getOperand(OpNo).isDef()) {
- MRInfo = isMod;
- } else {
- MRInfo = isRef;
- }
-
// add new memory reference
MI2VirtMap.insert(IP, std::make_pair(NewMI, std::make_pair(VirtReg, MRInfo)));
}
-void VirtRegMap::print(std::ostream &OS) const {
- const MRegisterInfo* MRI = MF.getTarget().getRegisterInfo();
-
- OS << "********** REGISTER MAP **********\n";
- for (unsigned i = MRegisterInfo::FirstVirtualRegister,
- e = MF.getSSARegMap()->getLastVirtReg(); i <= e; ++i) {
- if (Virt2PhysMap[i] != (unsigned)VirtRegMap::NO_PHYS_REG)
- OS << "[reg" << i << " -> " << MRI->getName(Virt2PhysMap[i]) << "]\n";
-
- }
-
- for (unsigned i = MRegisterInfo::FirstVirtualRegister,
- e = MF.getSSARegMap()->getLastVirtReg(); i <= e; ++i)
- if (Virt2StackSlotMap[i] != VirtRegMap::NO_STACK_SLOT)
- OS << "[reg" << i << " -> fi#" << Virt2StackSlotMap[i] << "]\n";
- OS << '\n';
-}
-
-void VirtRegMap::dump() const {
- print(DOUT);
-}
-
-
-//===----------------------------------------------------------------------===//
-// Simple Spiller Implementation
-//===----------------------------------------------------------------------===//
-
-Spiller::~Spiller() {}
-
-namespace {
- struct VISIBILITY_HIDDEN SimpleSpiller : public Spiller {
- bool runOnMachineFunction(MachineFunction& mf, VirtRegMap &VRM);
- };
+void VirtRegMap::virtFolded(unsigned VirtReg, MachineInstr *MI, ModRef MRInfo) {
+ MI2VirtMapTy::iterator IP = MI2VirtMap.lower_bound(MI);
+ MI2VirtMap.insert(IP, std::make_pair(MI, std::make_pair(VirtReg, MRInfo)));
}
-bool SimpleSpiller::runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM) {
- DOUT << "********** REWRITE MACHINE CODE **********\n";
- DOUT << "********** Function: " << MF.getFunction()->getName() << '\n';
- const TargetMachine &TM = MF.getTarget();
- const MRegisterInfo &MRI = *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.isRegister() && MO.getReg())
- if (MRegisterInfo::isVirtualRegister(MO.getReg())) {
- unsigned VirtReg = MO.getReg();
- unsigned PhysReg = VRM.getPhys(VirtReg);
- if (VRM.hasStackSlot(VirtReg)) {
- int StackSlot = VRM.getStackSlot(VirtReg);
- const TargetRegisterClass* RC =
- MF.getSSARegMap()->getRegClass(VirtReg);
-
- if (MO.isUse() &&
- std::find(LoadedRegs.begin(), LoadedRegs.end(), VirtReg)
- == LoadedRegs.end()) {
- MRI.loadRegFromStackSlot(MBB, &MI, PhysReg, StackSlot, RC);
- LoadedRegs.push_back(VirtReg);
- ++NumLoads;
- DOUT << '\t' << *prior(MII);
- }
-
- if (MO.isDef()) {
- MRI.storeRegToStackSlot(MBB, next(MII), PhysReg, StackSlot, RC);
- ++NumStores;
- }
- }
- MF.setPhysRegUsed(PhysReg);
- MI.getOperand(i).setReg(PhysReg);
- } else {
- MF.setPhysRegUsed(MO.getReg());
- }
- }
-
- DOUT << '\t' << MI;
- LoadedRegs.clear();
- }
- }
- return true;
-}
-
-//===----------------------------------------------------------------------===//
-// Local Spiller Implementation
-//===----------------------------------------------------------------------===//
-
-namespace {
- /// LocalSpiller - This spiller does a simple pass over the machine basic
- /// block to attempt to keep spills in registers as much as possible for
- /// blocks that have low register pressure (the vreg may be spilled due to
- /// register pressure in other blocks).
- class VISIBILITY_HIDDEN LocalSpiller : public Spiller {
- const MRegisterInfo *MRI;
- const TargetInstrInfo *TII;
- public:
- bool runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM) {
- MRI = MF.getTarget().getRegisterInfo();
- TII = MF.getTarget().getInstrInfo();
- DOUT << "\n**** Local spiller rewriting function '"
- << MF.getFunction()->getName() << "':\n";
-
- std::vector<MachineInstr *> ReMatedMIs;
- for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
- MBB != E; ++MBB)
- RewriteMBB(*MBB, VRM, ReMatedMIs);
- for (unsigned i = 0, e = ReMatedMIs.size(); i != e; ++i)
- delete ReMatedMIs[i];
- return true;
- }
- private:
- void RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM,
- std::vector<MachineInstr*> &ReMatedMIs);
- };
-}
-
-/// AvailableSpills - As the local spiller is scanning and rewriting an MBB from
-/// top down, keep track of which spills slots are available in each register.
-///
-/// Note that not all physregs are created equal here. In particular, some
-/// physregs are reloads that we are allowed to clobber or ignore at any time.
-/// Other physregs are values that the register allocated program is using that
-/// we cannot CHANGE, but we can read if we like. We keep track of this on a
-/// per-stack-slot basis as the low bit in the value of the SpillSlotsAvailable
-/// entries. The predicate 'canClobberPhysReg()' checks this bit and
-/// addAvailable sets it if.
-namespace {
-class VISIBILITY_HIDDEN AvailableSpills {
- const MRegisterInfo *MRI;
- const TargetInstrInfo *TII;
-
- // SpillSlotsAvailable - This map keeps track of all of the spilled virtual
- // register values that are still available, due to being loaded or stored to,
- // but not invalidated yet.
- std::map<int, unsigned> SpillSlotsAvailable;
-
- // PhysRegsAvailable - This is the inverse of SpillSlotsAvailable, indicating
- // which stack slot values are currently held by a physreg. This is used to
- // invalidate entries in SpillSlotsAvailable when a physreg is modified.
- std::multimap<unsigned, int> PhysRegsAvailable;
-
- void disallowClobberPhysRegOnly(unsigned PhysReg);
-
- void ClobberPhysRegOnly(unsigned PhysReg);
-public:
- AvailableSpills(const MRegisterInfo *mri, const TargetInstrInfo *tii)
- : MRI(mri), TII(tii) {
- }
-
- const MRegisterInfo *getRegInfo() const { return MRI; }
-
- /// getSpillSlotPhysReg - If the specified stack slot is available in a
- /// physical register, return that PhysReg, otherwise return 0.
- unsigned getSpillSlotPhysReg(int Slot) const {
- std::map<int, unsigned>::const_iterator I = SpillSlotsAvailable.find(Slot);
- if (I != SpillSlotsAvailable.end()) {
- return I->second >> 1; // Remove the CanClobber bit.
- }
- return 0;
- }
-
- /// addAvailable - Mark that the specified stack slot is available 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 Slot, MachineInstr *MI, unsigned Reg,
- bool CanClobber = true) {
- // If this stack slot is thought to be available in some other physreg,
- // remove its record.
- ModifyStackSlot(Slot);
-
- PhysRegsAvailable.insert(std::make_pair(Reg, Slot));
- SpillSlotsAvailable[Slot] = (Reg << 1) | (unsigned)CanClobber;
-
- if (Slot > VirtRegMap::MAX_STACK_SLOT)
- DOUT << "Remembering RM#" << Slot-VirtRegMap::MAX_STACK_SLOT-1;
- else
- DOUT << "Remembering SS#" << Slot;
- DOUT << " in physreg " << MRI->getName(Reg) << "\n";
- }
-
- /// canClobberPhysReg - Return true if the spiller is allowed to change the
- /// value of the specified stackslot register if it desires. The specified
- /// stack slot must be available in a physreg for this query to make sense.
- bool canClobberPhysReg(int Slot) const {
- assert(SpillSlotsAvailable.count(Slot) && "Slot not available!");
- return SpillSlotsAvailable.find(Slot)->second & 1;
- }
-
- /// disallowClobberPhysReg - Unset the CanClobber bit of the specified
- /// stackslot register. The register is still available but is no longer
- /// allowed to be modifed.
- void disallowClobberPhysReg(unsigned PhysReg);
-
- /// 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 ClobberPhysReg(unsigned PhysReg);
-
- /// ModifyStackSlot - 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 ModifyStackSlot(int Slot);
-};
-}
-
-/// 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 Slot = I->second;
- I++;
- assert((SpillSlotsAvailable[Slot] >> 1) == PhysReg &&
- "Bidirectional map mismatch!");
- SpillSlotsAvailable[Slot] &= ~1;
- DOUT << "PhysReg " << MRI->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 = MRI->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 Slot = I->second;
- PhysRegsAvailable.erase(I++);
- assert((SpillSlotsAvailable[Slot] >> 1) == PhysReg &&
- "Bidirectional map mismatch!");
- SpillSlotsAvailable.erase(Slot);
- DOUT << "PhysReg " << MRI->getName(PhysReg)
- << " clobbered, invalidating ";
- if (Slot > VirtRegMap::MAX_STACK_SLOT)
- DOUT << "RM#" << Slot-VirtRegMap::MAX_STACK_SLOT-1 << "\n";
- else
- DOUT << "SS#" << Slot << "\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 = MRI->getAliasSet(PhysReg); *AS; ++AS)
- ClobberPhysRegOnly(*AS);
- ClobberPhysRegOnly(PhysReg);
-}
-
-/// ModifyStackSlot - 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::ModifyStackSlot(int Slot) {
- std::map<int, unsigned>::iterator It = SpillSlotsAvailable.find(Slot);
- if (It == SpillSlotsAvailable.end()) return;
- unsigned Reg = It->second >> 1;
- SpillSlotsAvailable.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 == Slot) break;
- }
- PhysRegsAvailable.erase(I);
-}
-
-
-
-// ReusedOp - For each reused operand, we keep track of a bit of information, in
-// case we need to rollback upon processing a new operand. See comments below.
-namespace {
- struct ReusedOp {
- // The MachineInstr operand that reused an available value.
- unsigned Operand;
-
- // StackSlot - The spill slot of the value being reused.
- unsigned StackSlot;
-
- // PhysRegReused - The physical register the value was available in.
- unsigned PhysRegReused;
-
- // AssignedPhysReg - The physreg that was assigned for use by the reload.
- unsigned AssignedPhysReg;
-
- // VirtReg - The virtual register itself.
- unsigned VirtReg;
-
- ReusedOp(unsigned o, unsigned ss, unsigned prr, unsigned apr,
- unsigned vreg)
- : Operand(o), StackSlot(ss), PhysRegReused(prr), AssignedPhysReg(apr),
- VirtReg(vreg) {}
- };
-
- /// ReuseInfo - This maintains a collection of ReuseOp's for each operand that
- /// is reused instead of reloaded.
- class VISIBILITY_HIDDEN ReuseInfo {
- MachineInstr &MI;
- std::vector<ReusedOp> Reuses;
- BitVector PhysRegsClobbered;
- public:
- ReuseInfo(MachineInstr &mi, const MRegisterInfo *mri) : MI(mi) {
- PhysRegsClobbered.resize(mri->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 StackSlot,
- unsigned PhysRegReused, unsigned AssignedPhysReg,
- unsigned VirtReg) {
- // 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, StackSlot, PhysRegReused,
- AssignedPhysReg, VirtReg));
- }
-
- void markClobbered(unsigned PhysReg) {
- PhysRegsClobbered.set(PhysReg);
- }
-
- 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.
- unsigned GetRegForReload(unsigned PhysReg, MachineInstr *MI,
- AvailableSpills &Spills,
- std::map<int, MachineInstr*> &MaybeDeadStores,
- SmallSet<unsigned, 8> &Rejected) {
- 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);
- } 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 MRegisterInfo *MRI = Spills.getRegInfo();
- if (MRI->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()->getSSARegMap()->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);
-
- MRI->loadRegFromStackSlot(*MBB, MI, NewPhysReg,
- NewOp.StackSlot, AliasRC);
- Spills.ClobberPhysReg(NewPhysReg);
- Spills.ClobberPhysReg(NewOp.PhysRegReused);
-
- // Any stores to this stack slot are not dead anymore.
- MaybeDeadStores.erase(NewOp.StackSlot);
-
- MI->getOperand(NewOp.Operand).setReg(NewPhysReg);
-
- Spills.addAvailable(NewOp.StackSlot, MI, NewPhysReg);
- ++NumLoads;
- DEBUG(MachineBasicBlock::iterator MII = MI;
- DOUT << '\t' << *prior(MII));
-
- DOUT << "Reuse undone!\n";
- --NumReused;
-
- // Finally, PhysReg is now available, go ahead and use it.
- return PhysReg;
- }
- }
- }
- return PhysReg;
- }
-
- /// GetRegForReload - Helper for the above GetRegForReload(). Add a
- /// 'Rejected' set to remember which registers have been considered and
- /// rejected for the reload. This avoids infinite looping in case like
- /// this:
- /// t1 := op t2, t3
- /// t2 <- assigned r0 for use by the reload but ended up reuse r1
- /// t3 <- assigned r1 for use by the reload but ended up reuse r0
- /// t1 <- desires r1
- /// sees r1 is taken by t2, tries t2's reload register r0
- /// sees r0 is taken by t3, tries t3's reload register r1
- /// sees r1 is taken by t2, tries t2's reload register r0 ...
- unsigned GetRegForReload(unsigned PhysReg, MachineInstr *MI,
- AvailableSpills &Spills,
- std::map<int, MachineInstr*> &MaybeDeadStores) {
- SmallSet<unsigned, 8> Rejected;
- return GetRegForReload(PhysReg, MI, Spills, MaybeDeadStores, Rejected);
- }
- };
-}
-
-
-/// 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) {
- 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 (KillOps[Reg] == &MO) {
- RegKills.reset(Reg);
- KillOps[Reg] = NULL;
- }
- }
-}
-
-/// 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 TargetInstrDescriptor *TID = MI.getInstrDescriptor();
- for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI.getOperand(i);
- if (!MO.isReg() || !MO.isUse())
+void VirtRegMap::RemoveMachineInstrFromMaps(MachineInstr *MI) {
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = MI->getOperand(i);
+ if (!MO.isFI())
continue;
- unsigned Reg = MO.getReg();
- if (Reg == 0)
+ int FI = MO.getIndex();
+ if (MF->getFrameInfo()->isFixedObjectIndex(FI))
continue;
-
- if (RegKills[Reg]) {
- // That can't be right. Register is killed but not re-defined and it's
- // being reused. Let's fix that.
- KillOps[Reg]->unsetIsKill();
- if (i < TID->numOperands &&
- TID->getOperandConstraint(i, TOI::TIED_TO) == -1)
- // 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())
+ // This stack reference was produced by instruction selection and
+ // is not a spill
+ if (FI < LowSpillSlot)
continue;
- unsigned Reg = MO.getReg();
- RegKills.reset(Reg);
- KillOps[Reg] = NULL;
+ assert((unsigned)FI-LowSpillSlot < SpillSlotToUsesMap.size()
+ && "Invalid spill slot");
+ SpillSlotToUsesMap[FI-LowSpillSlot].erase(MI);
}
+ MI2VirtMap.erase(MI);
+ SpillPt2VirtMap.erase(MI);
+ RestorePt2VirtMap.erase(MI);
+ EmergencySpillMap.erase(MI);
}
+/// FindUnusedRegisters - Gather a list of allocatable registers that
+/// have not been allocated to any virtual register.
+bool VirtRegMap::FindUnusedRegisters(LiveIntervals* LIs) {
+ unsigned NumRegs = TRI->getNumRegs();
+ UnusedRegs.reset();
+ UnusedRegs.resize(NumRegs);
-/// rewriteMBB - Keep track of which spills are available even after the
-/// register allocator is done with them. If possible, avoid reloading vregs.
-void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM,
- std::vector<MachineInstr*> &ReMatedMIs) {
- DOUT << MBB.getBasicBlock()->getName() << ":\n";
-
- // Spills - Keep track of which spilled values are available in physregs so
- // that we can choose to reuse the physregs instead of emitting reloads.
- AvailableSpills Spills(MRI, TII);
-
- // 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::map<int, MachineInstr*> MaybeDeadStores;
-
- // Keep track of kill information.
- BitVector RegKills(MRI->getNumRegs());
- std::vector<MachineOperand*> KillOps;
- KillOps.resize(MRI->getNumRegs(), NULL);
-
- MachineFunction &MF = *MBB.getParent();
- for (MachineBasicBlock::iterator MII = MBB.begin(), E = MBB.end();
- MII != E; ) {
- MachineInstr &MI = *MII;
- MachineBasicBlock::iterator NextMII = MII; ++NextMII;
- VirtRegMap::MI2VirtMapTy::const_iterator I, End;
-
- bool Erased = false;
- bool BackTracked = false;
-
- /// ReusedOperands - Keep track of operand reuse in case we need to undo
- /// reuse.
- ReuseInfo ReusedOperands(MI, MRI);
-
- // Loop over all of the implicit defs, clearing them from our available
- // sets.
- const TargetInstrDescriptor *TID = MI.getInstrDescriptor();
-
- // If this instruction is being rematerialized, just remove it!
- int FrameIdx;
- if (TII->isTriviallyReMaterializable(&MI) ||
- TII->isLoadFromStackSlot(&MI, FrameIdx)) {
- Erased = true;
- for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI.getOperand(i);
- if (!MO.isRegister() || MO.getReg() == 0)
- continue; // Ignore non-register operands.
- if (MO.isDef() && !VRM.isReMaterialized(MO.getReg())) {
- Erased = false;
+ BitVector Used(NumRegs);
+ for (unsigned i = TargetRegisterInfo::FirstVirtualRegister,
+ e = MF->getRegInfo().getLastVirtReg(); i <= e; ++i)
+ if (Virt2PhysMap[i] != (unsigned)VirtRegMap::NO_PHYS_REG)
+ Used.set(Virt2PhysMap[i]);
+
+ BitVector Allocatable = TRI->getAllocatableSet(*MF);
+ bool AnyUnused = false;
+ for (unsigned Reg = 1; Reg < NumRegs; ++Reg) {
+ if (Allocatable[Reg] && !Used[Reg] && !LIs->hasInterval(Reg)) {
+ bool ReallyUnused = true;
+ for (const unsigned *AS = TRI->getAliasSet(Reg); *AS; ++AS) {
+ if (Used[*AS] || LIs->hasInterval(*AS)) {
+ ReallyUnused = false;
break;
}
}
- if (Erased) {
- VRM.RemoveFromFoldedVirtMap(&MI);
- ReMatedMIs.push_back(MI.removeFromParent());
- goto ProcessNextInst;
- }
- }
-
- if (TID->ImplicitDefs) {
- const unsigned *ImpDef = TID->ImplicitDefs;
- for ( ; *ImpDef; ++ImpDef) {
- MF.setPhysRegUsed(*ImpDef);
- ReusedOperands.markClobbered(*ImpDef);
- Spills.ClobberPhysReg(*ImpDef);
- }
- }
-
- // Process all of the spilled uses and all non spilled reg references.
- for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI.getOperand(i);
- if (!MO.isRegister() || MO.getReg() == 0)
- continue; // Ignore non-register operands.
-
- if (MRegisterInfo::isPhysicalRegister(MO.getReg())) {
- // Ignore physregs for spilling, but remember that it is used by this
- // function.
- MF.setPhysRegUsed(MO.getReg());
- ReusedOperands.markClobbered(MO.getReg());
- continue;
- }
-
- assert(MRegisterInfo::isVirtualRegister(MO.getReg()) &&
- "Not a virtual or a physical register?");
-
- unsigned VirtReg = MO.getReg();
- if (!VRM.hasStackSlot(VirtReg)) {
- // This virtual register was assigned a physreg!
- unsigned Phys = VRM.getPhys(VirtReg);
- MF.setPhysRegUsed(Phys);
- if (MO.isDef())
- ReusedOperands.markClobbered(Phys);
- MI.getOperand(i).setReg(Phys);
- 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 StackSlot = VRM.getStackSlot(VirtReg);
- unsigned PhysReg;
-
- // Check to see if this stack slot is available.
- if ((PhysReg = Spills.getSpillSlotPhysReg(StackSlot))) {
- // 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;
- int ti = TID->getOperandConstraint(i, TOI::TIED_TO);
- if (ti != -1 &&
- MI.getOperand(ti).isReg() &&
- MI.getOperand(ti).getReg() == VirtReg) {
- // 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 = Spills.canClobberPhysReg(StackSlot) &&
- !ReusedOperands.isClobbered(PhysReg);
- }
-
- if (CanReuse) {
- // If this stack slot value is already available, reuse it!
- if (StackSlot > VirtRegMap::MAX_STACK_SLOT)
- DOUT << "Reusing RM#" << StackSlot-VirtRegMap::MAX_STACK_SLOT-1;
- else
- DOUT << "Reusing SS#" << StackSlot;
- DOUT << " from physreg "
- << MRI->getName(PhysReg) << " for vreg"
- << VirtReg <<" instead of reloading into physreg "
- << MRI->getName(VRM.getPhys(VirtReg)) << "\n";
- MI.getOperand(i).setReg(PhysReg);
-
- // 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, StackSlot, PhysReg,
- VRM.getPhys(VirtReg), VirtReg);
- if (ti != -1)
- // Only mark it clobbered if this is a use&def operand.
- ReusedOperands.markClobbered(PhysReg);
- ++NumReused;
- continue;
- }
-
- // 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);
-
- // 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 (StackSlot > VirtRegMap::MAX_STACK_SLOT)
- DOUT << "Reusing RM#" << StackSlot-VirtRegMap::MAX_STACK_SLOT-1;
- else
- DOUT << "Reusing SS#" << StackSlot;
- DOUT << " from physreg " << MRI->getName(PhysReg) << " for vreg"
- << VirtReg
- << " instead of reloading into same physreg.\n";
- MI.getOperand(i).setReg(PhysReg);
- ReusedOperands.markClobbered(PhysReg);
- ++NumReused;
- continue;
- }
-
- const TargetRegisterClass* RC = MF.getSSARegMap()->getRegClass(VirtReg);
- MF.setPhysRegUsed(DesignatedReg);
- ReusedOperands.markClobbered(DesignatedReg);
- MRI->copyRegToReg(MBB, &MI, DesignatedReg, PhysReg, RC);
-
- MachineInstr *CopyMI = prior(MII);
- UpdateKills(*CopyMI, RegKills, KillOps);
-
- // This invalidates DesignatedReg.
- Spills.ClobberPhysReg(DesignatedReg);
-
- Spills.addAvailable(StackSlot, &MI, DesignatedReg);
- MI.getOperand(i).setReg(DesignatedReg);
- DOUT << '\t' << *prior(MII);
- ++NumReused;
- continue;
- }
-
- // Otherwise, reload it and remember that we have it.
- PhysReg = VRM.getPhys(VirtReg);
- assert(PhysReg && "Must map virtreg to physreg!");
- const TargetRegisterClass* RC = MF.getSSARegMap()->getRegClass(VirtReg);
-
- // 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);
-
- MF.setPhysRegUsed(PhysReg);
- ReusedOperands.markClobbered(PhysReg);
- if (doReMat) {
- MRI->reMaterialize(MBB, &MI, PhysReg, VRM.getReMaterializedMI(VirtReg));
- ++NumReMats;
- } else {
- MRI->loadRegFromStackSlot(MBB, &MI, PhysReg, StackSlot, RC);
- ++NumLoads;
- }
- // This invalidates PhysReg.
- Spills.ClobberPhysReg(PhysReg);
-
- // Any stores to this stack slot are not dead anymore.
- if (!doReMat)
- MaybeDeadStores.erase(StackSlot);
- Spills.addAvailable(StackSlot, &MI, PhysReg);
- // Assumes this is the last use. IsKill will be unset if reg is reused
- // unless it's a two-address operand.
- if (TID->getOperandConstraint(i, TOI::TIED_TO) == -1)
- MI.getOperand(i).setIsKill();
- MI.getOperand(i).setReg(PhysReg);
- UpdateKills(*prior(MII), RegKills, KillOps);
- DOUT << '\t' << *prior(MII);
- }
-
- 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
- for (tie(I, End) = VRM.getFoldedVirts(&MI); I != End; ++I) {
- DOUT << "Folded vreg: " << I->second.first << " MR: "
- << I->second.second;
- unsigned VirtReg = I->second.first;
- VirtRegMap::ModRef MR = I->second.second;
- if (!VRM.hasStackSlot(VirtReg)) {
- DOUT << ": No stack slot!\n";
- continue;
- }
- int SS = VRM.getStackSlot(VirtReg);
- 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;
- if (unsigned DestReg = TII->isLoadFromStackSlot(&MI, FrameIdx)) {
- if (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.getSpillSlotPhysReg(SS)) {
- DOUT << "Promoted Load To Copy: " << MI;
- if (DestReg != InReg) {
- MRI->copyRegToReg(MBB, &MI, DestReg, InReg,
- MF.getSSARegMap()->getRegClass(VirtReg));
- // 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.
- BackTracked = true;
- } else
- DOUT << "Removing now-noop copy: " << MI;
-
- VRM.RemoveFromFoldedVirtMap(&MI);
- MBB.erase(&MI);
- Erased = 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.
- std::map<int, MachineInstr*>::iterator MDSI = MaybeDeadStores.find(SS);
- if (MDSI != MaybeDeadStores.end()) {
- if (MR & VirtRegMap::isRef) // Previous store is not dead.
- MaybeDeadStores.erase(MDSI);
- else {
- // If we get here, the store is dead, nuke it now.
- assert(VirtRegMap::isMod && "Can't be modref!");
- DOUT << "Removed dead store:\t" << *MDSI->second;
- InvalidateKills(*MDSI->second, RegKills, KillOps);
- MBB.erase(MDSI->second);
- VRM.RemoveFromFoldedVirtMap(MDSI->second);
- MaybeDeadStores.erase(MDSI);
- ++NumDSE;
- }
- }
-
- // 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.ModifyStackSlot(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(MRegisterInfo::isPhysicalRegister(SrcReg) &&
- "Src hasn't been allocated yet?");
- // 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, &MI, SrcReg, false/*don't clobber*/);
- }
- }
+ if (ReallyUnused) {
+ AnyUnused = true;
+ UnusedRegs.set(Reg);
}
}
+ }
- // Process all of the spilled defs.
- for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI.getOperand(i);
- if (MO.isRegister() && MO.getReg() && MO.isDef()) {
- unsigned VirtReg = MO.getReg();
-
- if (!MRegisterInfo::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;
- if (TII->isMoveInstr(MI, Src, Dst) && Src == Dst) {
- ++NumDCE;
- DOUT << "Removing now-noop copy: " << MI;
- MBB.erase(&MI);
- Erased = true;
- VRM.RemoveFromFoldedVirtMap(&MI);
- 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!");
-
- // Otherwise, if it wasn't available, remember that it is now!
- Spills.addAvailable(FrameIdx, &MI, DestReg);
- goto ProcessNextInst;
- }
-
- continue;
- }
-
- // The only vregs left are stack slot definitions.
- int StackSlot = VRM.getStackSlot(VirtReg);
- const TargetRegisterClass *RC = MF.getSSARegMap()->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;
- int TiedOp = MI.getInstrDescriptor()->findTiedToSrcOperand(i);
- if (TiedOp != -1)
- PhysReg = MI.getOperand(TiedOp).getReg();
- 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);
- }
- }
-
- MF.setPhysRegUsed(PhysReg);
- ReusedOperands.markClobbered(PhysReg);
- MRI->storeRegToStackSlot(MBB, next(MII), PhysReg, StackSlot, RC);
- DOUT << "Store:\t" << *next(MII);
- MI.getOperand(i).setReg(PhysReg);
-
- // If there is a dead store to this stack slot, nuke it now.
- MachineInstr *&LastStore = MaybeDeadStores[StackSlot];
- if (LastStore) {
- DOUT << "Removed dead store:\t" << *LastStore;
- ++NumDSE;
- InvalidateKills(*LastStore, RegKills, KillOps);
- MBB.erase(LastStore);
- VRM.RemoveFromFoldedVirtMap(LastStore);
- }
- LastStore = next(MII);
+ return AnyUnused;
+}
- // If the stack slot value was previously available in some other
- // register, change it now. Otherwise, make the register available,
- // in PhysReg.
- Spills.ModifyStackSlot(StackSlot);
- Spills.ClobberPhysReg(PhysReg);
- Spills.addAvailable(StackSlot, LastStore, PhysReg);
- ++NumStores;
+void VirtRegMap::print(raw_ostream &OS, const Module* M) const {
+ const TargetRegisterInfo* TRI = MF->getTarget().getRegisterInfo();
+ const MachineRegisterInfo &MRI = MF->getRegInfo();
- // 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;
- if (TII->isMoveInstr(MI, Src, Dst) && Src == Dst) {
- ++NumDCE;
- DOUT << "Removing now-noop copy: " << MI;
- MBB.erase(&MI);
- Erased = true;
- VRM.RemoveFromFoldedVirtMap(&MI);
- goto ProcessNextInst;
- }
- }
- }
- }
- ProcessNextInst:
- if (!Erased && !BackTracked)
- for (MachineBasicBlock::iterator II = MI; II != NextMII; ++II)
- UpdateKills(*II, RegKills, KillOps);
- MII = NextMII;
+ OS << "********** REGISTER MAP **********\n";
+ for (unsigned i = TargetRegisterInfo::FirstVirtualRegister,
+ e = MF->getRegInfo().getLastVirtReg(); i <= e; ++i) {
+ if (Virt2PhysMap[i] != (unsigned)VirtRegMap::NO_PHYS_REG)
+ OS << "[reg" << i << " -> " << TRI->getName(Virt2PhysMap[i])
+ << "] " << MRI.getRegClass(i)->getName() << "\n";
}
-}
+ for (unsigned i = TargetRegisterInfo::FirstVirtualRegister,
+ e = MF->getRegInfo().getLastVirtReg(); i <= e; ++i)
+ if (Virt2StackSlotMap[i] != VirtRegMap::NO_STACK_SLOT)
+ OS << "[reg" << i << " -> fi#" << Virt2StackSlotMap[i]
+ << "] " << MRI.getRegClass(i)->getName() << "\n";
+ OS << '\n';
+}
-llvm::Spiller* llvm::createSpiller() {
- switch (SpillerOpt) {
- default: assert(0 && "Unreachable!");
- case local:
- return new LocalSpiller();
- case simple:
- return new SimpleSpiller();
- }
+void VirtRegMap::dump() const {
+ print(dbgs());
}