#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Compiler.h"
+#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallSet.h"
#include <algorithm>
-#include <iostream>
using namespace llvm;
-namespace {
- static Statistic<> NumSpills("spiller", "Number of register spills");
- static Statistic<> NumStores("spiller", "Number of stores added");
- static Statistic<> NumLoads ("spiller", "Number of loads added");
- static Statistic<> NumReused("spiller", "Number of values reused");
- static Statistic<> NumDSE ("spiller", "Number of dead stores elided");
- static Statistic<> NumDCE ("spiller", "Number of copies elided");
+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>
VirtRegMap::VirtRegMap(MachineFunction &mf)
: TII(*mf.getTarget().getInstrInfo()), MF(mf),
- Virt2PhysMap(NO_PHYS_REG), Virt2StackSlotMap(NO_STACK_SLOT) {
+ Virt2PhysMap(NO_PHYS_REG), Virt2StackSlotMap(NO_STACK_SLOT),
+ ReMatId(MAX_STACK_SLOT+1) {
grow();
}
assert(MRegisterInfo::isVirtualRegister(virtReg));
assert(Virt2StackSlotMap[virtReg] == NO_STACK_SLOT &&
"attempt to assign stack slot to already spilled register");
+ assert((frameIndex >= 0 ||
+ (frameIndex >= MF.getFrameInfo()->getObjectIndexBegin())) &&
+ "illegal fixed frame index");
Virt2StackSlotMap[virtReg] = frameIndex;
}
+int VirtRegMap::assignVirtReMatId(unsigned virtReg) {
+ assert(MRegisterInfo::isVirtualRegister(virtReg));
+ assert(Virt2StackSlotMap[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;
+ return ReMatId++;
+}
+
void VirtRegMap::virtFolded(unsigned VirtReg, MachineInstr *OldMI,
unsigned OpNo, MachineInstr *NewMI) {
// Move previous memory references folded to new instruction.
}
ModRef MRInfo;
- if (OpNo < 2 && TII.isTwoAddrInstr(OldMI->getOpcode())) {
+ 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()) {
OS << '\n';
}
-void VirtRegMap::dump() const { print(std::cerr); }
+void VirtRegMap::dump() const {
+ print(DOUT);
+}
//===----------------------------------------------------------------------===//
}
bool SimpleSpiller::runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM) {
- DEBUG(std::cerr << "********** REWRITE MACHINE CODE **********\n");
- DEBUG(std::cerr << "********** Function: "
- << MF.getFunction()->getName() << '\n');
+ DOUT << "********** REWRITE MACHINE CODE **********\n";
+ DOUT << "********** Function: " << MF.getFunction()->getName() << '\n';
const TargetMachine &TM = MF.getTarget();
const MRegisterInfo &MRI = *TM.getRegisterInfo();
- bool *PhysRegsUsed = MF.getUsedPhysregs();
// 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
for (MachineFunction::iterator MBBI = MF.begin(), E = MF.end();
MBBI != E; ++MBBI) {
- DEBUG(std::cerr << MBBI->getBasicBlock()->getName() << ":\n");
+ DOUT << MBBI->getBasicBlock()->getName() << ":\n";
MachineBasicBlock &MBB = *MBBI;
for (MachineBasicBlock::iterator MII = MBB.begin(),
E = MBB.end(); MII != E; ++MII) {
MRI.loadRegFromStackSlot(MBB, &MI, PhysReg, StackSlot, RC);
LoadedRegs.push_back(VirtReg);
++NumLoads;
- DEBUG(std::cerr << '\t' << *prior(MII));
+ DOUT << '\t' << *prior(MII);
}
if (MO.isDef()) {
++NumStores;
}
}
- PhysRegsUsed[PhysReg] = true;
+ MF.setPhysRegUsed(PhysReg);
MI.getOperand(i).setReg(PhysReg);
} else {
- PhysRegsUsed[MO.getReg()] = true;
+ MF.setPhysRegUsed(MO.getReg());
}
}
- DEBUG(std::cerr << '\t' << MI);
+ DOUT << '\t' << MI;
LoadedRegs.clear();
}
}
bool runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM) {
MRI = MF.getTarget().getRegisterInfo();
TII = MF.getTarget().getInstrInfo();
- DEBUG(std::cerr << "\n**** Local spiller rewriting function '"
- << MF.getFunction()->getName() << "':\n");
+ 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);
+ 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);
- void ClobberPhysReg(unsigned PR, std::map<int, unsigned> &SpillSlots,
- std::multimap<unsigned, int> &PhysRegs);
- void ClobberPhysRegOnly(unsigned PR, std::map<int, unsigned> &SpillSlots,
- std::multimap<unsigned, int> &PhysRegs);
- void ModifyStackSlot(int Slot, std::map<int, unsigned> &SpillSlots,
- std::multimap<unsigned, int> &PhysRegs);
+ void RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM,
+ std::vector<MachineInstr*> &ReMatedMIs);
};
}
// 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;
+ // but not invalidated yet. It also tracks the instructions that defined
+ // or used the register.
+ typedef std::pair<unsigned, std::vector<MachineInstr*> > SSInfo;
+ std::map<int, SSInfo> 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.
+ /// physical register, return that PhysReg, otherwise return 0. It also
+ /// returns by reference the instruction that either defines or last uses
+ /// the register.
+ unsigned getSpillSlotPhysReg(int Slot, MachineInstr *&SSMI) const {
+ std::map<int, SSInfo>::const_iterator I = SpillSlotsAvailable.find(Slot);
+ if (I != SpillSlotsAvailable.end()) {
+ if (!I->second.second.empty())
+ SSMI = I->second.second.back();
+ return I->second.first >> 1; // Remove the CanClobber bit.
+ }
return 0;
}
-
- const MRegisterInfo *getRegInfo() const { return MRI; }
+ /// addLastUse - Add the last use information of all stack slots whose
+ /// values are available in the specific register.
+ void addLastUse(unsigned PhysReg, MachineInstr *Use) {
+ std::multimap<unsigned, int>::iterator I =
+ PhysRegsAvailable.lower_bound(PhysReg);
+ while (I != PhysRegsAvailable.end() && I->first == PhysReg) {
+ int Slot = I->second;
+ I++;
+
+ std::map<int, SSInfo>::iterator II = SpillSlotsAvailable.find(Slot);
+ assert(II != SpillSlotsAvailable.end() && "Slot not available!");
+ unsigned Val = II->second.first;
+ assert((Val >> 1) == PhysReg && "Bidirectional map mismatch!");
+ // This can be true if there are multiple uses of the same register.
+ if (II->second.second.back() != Use)
+ II->second.second.push_back(Use);
+ }
+ }
+
+ /// removeLastUse - Remove the last use information of all stack slots whose
+ /// values are available in the specific register.
+ void removeLastUse(unsigned PhysReg, MachineInstr *Use) {
+ std::multimap<unsigned, int>::iterator I =
+ PhysRegsAvailable.lower_bound(PhysReg);
+ while (I != PhysRegsAvailable.end() && I->first == PhysReg) {
+ int Slot = I->second;
+ I++;
+
+ std::map<int, SSInfo>::iterator II = SpillSlotsAvailable.find(Slot);
+ assert(II != SpillSlotsAvailable.end() && "Slot not available!");
+ unsigned Val = II->second.first;
+ assert((Val >> 1) == PhysReg && "Bidirectional map mismatch!");
+ if (II->second.second.back() == Use)
+ II->second.second.pop_back();
+ }
+ }
+
/// 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, unsigned Reg, bool CanClobber = true) {
+ 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;
+ std::vector<MachineInstr*> DefUses;
+ DefUses.push_back(MI);
+ SpillSlotsAvailable[Slot] =
+ std::make_pair((Reg << 1) | (unsigned)CanClobber, DefUses);
- DEBUG(std::cerr << "Remembering SS#" << Slot << " in physreg "
- << MRI->getName(Reg) << "\n");
+ 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;
+ return SpillSlotsAvailable.find(Slot)->second.first & 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.
};
}
+/// 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].first >> 1) == PhysReg &&
+ "Bidirectional map mismatch!");
+ SpillSlotsAvailable[Slot].first &= ~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) {
while (I != PhysRegsAvailable.end() && I->first == PhysReg) {
int Slot = I->second;
PhysRegsAvailable.erase(I++);
- assert((SpillSlotsAvailable[Slot] >> 1) == PhysReg &&
+ assert((SpillSlotsAvailable[Slot].first >> 1) == PhysReg &&
"Bidirectional map mismatch!");
SpillSlotsAvailable.erase(Slot);
- DEBUG(std::cerr << "PhysReg " << MRI->getName(PhysReg)
- << " clobbered, invalidating SS#" << Slot << "\n");
+ 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";
}
}
/// 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);
+ std::map<int, SSInfo>::iterator It = SpillSlotsAvailable.find(Slot);
if (It == SpillSlotsAvailable.end()) return;
- unsigned Reg = It->second >> 1;
+ unsigned Reg = It->second.first >> 1;
SpillSlotsAvailable.erase(It);
// This register may hold the value of multiple stack slots, only remove this
class VISIBILITY_HIDDEN ReuseInfo {
MachineInstr &MI;
std::vector<ReusedOp> Reuses;
+ BitVector PhysRegsClobbered;
public:
- ReuseInfo(MachineInstr &mi) : MI(mi) {}
+ ReuseInfo(MachineInstr &mi, const MRegisterInfo *mri) : MI(mi) {
+ PhysRegsClobbered.resize(mri->getNumRegs());
+ }
bool hasReuses() const {
return !Reuses.empty();
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) {
+ 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.
- if (Op.PhysRegReused == PhysReg) {
+ // 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;
-
- // Remove the record for the previous reuse. We know it can never be
- // invalidated now.
- Reuses.erase(Reuses.begin()+ro);
- return GetRegForReload(NewReg, MI, Spills, MaybeDeadStores);
+ 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
// 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);
+ MI, Spills, MaybeDeadStores, Rejected);
MRI->loadRegFromStackSlot(*MBB, MI, NewPhysReg,
NewOp.StackSlot, AliasRC);
MI->getOperand(NewOp.Operand).setReg(NewPhysReg);
- Spills.addAvailable(NewOp.StackSlot, NewPhysReg);
+ Spills.addAvailable(NewOp.StackSlot, MI, NewPhysReg);
++NumLoads;
DEBUG(MachineBasicBlock::iterator MII = MI;
- std::cerr << '\t' << *prior(MII));
+ DOUT << '\t' << *prior(MII));
- DEBUG(std::cerr << "Reuse undone!\n");
+ DOUT << "Reuse undone!\n";
--NumReused;
// Finally, PhysReg is now available, go ahead and use it.
}
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);
+ }
};
}
/// 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) {
-
- DEBUG(std::cerr << MBB.getBasicBlock()->getName() << ":\n");
+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.
// same stack slot, the original store is deleted.
std::map<int, MachineInstr*> MaybeDeadStores;
- bool *PhysRegsUsed = MBB.getParent()->getUsedPhysregs();
-
+ MachineFunction &MF = *MBB.getParent();
for (MachineBasicBlock::iterator MII = MBB.begin(), E = MBB.end();
MII != E; ) {
MachineInstr &MI = *MII;
/// ReusedOperands - Keep track of operand reuse in case we need to undo
/// reuse.
- ReuseInfo ReusedOperands(MI);
-
+ 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 ((TID->Flags & M_REMATERIALIZIBLE) ||
+ TII->isLoadFromStackSlot(&MI, FrameIdx)) {
+ bool Remove = 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())) {
+ Remove = false;
+ break;
+ }
+ }
+ if (Remove) {
+ VRM.RemoveFromFoldedVirtMap(&MI);
+ ReMatedMIs.push_back(MI.removeFromParent());
+ MII = NextMII;
+ continue;
+ }
+ }
+
+ const unsigned *ImpDef = TID->ImplicitDefs;
+ if (ImpDef) {
+ 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 (MRegisterInfo::isPhysicalRegister(MO.getReg())) {
// Ignore physregs for spilling, but remember that it is used by this
// function.
- PhysRegsUsed[MO.getReg()] = true;
+ MF.setPhysRegUsed(MO.getReg());
+ ReusedOperands.markClobbered(MO.getReg());
continue;
}
if (!VRM.hasStackSlot(VirtReg)) {
// This virtual register was assigned a physreg!
unsigned Phys = VRM.getPhys(VirtReg);
- PhysRegsUsed[Phys] = true;
+ MF.setPhysRegUsed(Phys);
+ if (MO.isDef())
+ ReusedOperands.markClobbered(Phys);
MI.getOperand(i).setReg(Phys);
continue;
}
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))) {
-
+ MachineInstr *SSMI = NULL;
+ if ((PhysReg = Spills.getSpillSlotPhysReg(StackSlot, SSMI))) {
// 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;
- if (i == 1 && MI.getOperand(0).isReg() &&
- MI.getOperand(0).getReg() == VirtReg &&
- TII->isTwoAddrInstr(MI.getOpcode())) {
+ 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.
- CanReuse = Spills.canClobberPhysReg(StackSlot);
+ // 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!
- DEBUG(std::cerr << "Reusing SS#" << StackSlot << " from physreg "
- << MRI->getName(PhysReg) << " for vreg"
- << VirtReg <<" instead of reloading into physreg "
- << MRI->getName(VRM.getPhys(VirtReg)) << "\n");
+ 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);
+ // Extend the live range of the MI that last kill the register if
+ // necessary.
+ bool WasKill = false;
+ if (SSMI) {
+ int UIdx = SSMI->findRegisterUseOperand(PhysReg, true);
+ if (UIdx != -1) {
+ MachineOperand &MOK = SSMI->getOperand(UIdx);
+ WasKill = MOK.isKill();
+ MOK.unsetIsKill();
+ }
+ }
+ if (ti == -1) {
+ // Unless it's the use of a two-address code, transfer the kill
+ // of the reused register to this use.
+ if (WasKill)
+ MI.getOperand(i).setIsKill();
+ Spills.addLastUse(PhysReg, &MI);
+ }
+
// 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'.
// 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;
}
// incoming, we don't need to inserted a dead copy.
if (DesignatedReg == PhysReg) {
// If this stack slot value is already available, reuse it!
- DEBUG(std::cerr << "Reusing SS#" << StackSlot << " from physreg "
- << MRI->getName(PhysReg) << " for vreg"
- << VirtReg
- << " instead of reloading into same physreg.\n");
+ 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 =
- MBB.getParent()->getSSARegMap()->getRegClass(VirtReg);
-
- PhysRegsUsed[DesignatedReg] = true;
+ const TargetRegisterClass* RC = MF.getSSARegMap()->getRegClass(VirtReg);
+ MF.setPhysRegUsed(DesignatedReg);
+ ReusedOperands.markClobbered(DesignatedReg);
MRI->copyRegToReg(MBB, &MI, DesignatedReg, PhysReg, RC);
-
+
+ // Extend the live range of the MI that last kill the register if
+ // necessary.
+ bool WasKill = false;
+ if (SSMI) {
+ int UIdx = SSMI->findRegisterUseOperand(PhysReg, true);
+ if (UIdx != -1) {
+ MachineOperand &MOK = SSMI->getOperand(UIdx);
+ WasKill = MOK.isKill();
+ MOK.unsetIsKill();
+ }
+ }
+ MachineInstr *CopyMI = prior(MII);
+ if (WasKill) {
+ // Transfer kill to the next use.
+ int UIdx = CopyMI->findRegisterUseOperand(PhysReg);
+ assert(UIdx != -1);
+ MachineOperand &MOU = CopyMI->getOperand(UIdx);
+ MOU.setIsKill();
+ }
+ Spills.addLastUse(PhysReg, CopyMI);
+
// This invalidates DesignatedReg.
Spills.ClobberPhysReg(DesignatedReg);
- Spills.addAvailable(StackSlot, DesignatedReg);
+ Spills.addAvailable(StackSlot, &MI, DesignatedReg);
MI.getOperand(i).setReg(DesignatedReg);
- DEBUG(std::cerr << '\t' << *prior(MII));
+ 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 =
- MBB.getParent()->getSSARegMap()->getRegClass(VirtReg);
+ 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
PhysReg = ReusedOperands.GetRegForReload(PhysReg, &MI,
Spills, MaybeDeadStores);
- PhysRegsUsed[PhysReg] = true;
- MRI->loadRegFromStackSlot(MBB, &MI, PhysReg, StackSlot, RC);
+ 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.
- MaybeDeadStores.erase(StackSlot);
- Spills.addAvailable(StackSlot, PhysReg);
- ++NumLoads;
+ 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);
- DEBUG(std::cerr << '\t' << *prior(MII));
- }
-
- // Loop over all of the implicit defs, clearing them from our available
- // sets.
- const unsigned *ImpDef = TII->getImplicitDefs(MI.getOpcode());
- if (ImpDef) {
- for ( ; *ImpDef; ++ImpDef) {
- PhysRegsUsed[*ImpDef] = true;
- Spills.ClobberPhysReg(*ImpDef);
- }
+ DOUT << '\t' << *prior(MII);
}
- DEBUG(std::cerr << '\t' << MI);
+ 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
VirtRegMap::MI2VirtMapTy::const_iterator I, End;
for (tie(I, End) = VRM.getFoldedVirts(&MI); I != End; ++I) {
- DEBUG(std::cerr << "Folded vreg: " << I->second.first << " MR: "
- << I->second.second);
+ 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)) {
- DEBUG(std::cerr << ": No stack slot!\n");
+ DOUT << ": No stack slot!\n";
continue;
}
int SS = VRM.getStackSlot(VirtReg);
- DEBUG(std::cerr << " - StackSlot: " << SS << "\n");
+ 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 (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)) {
- DEBUG(std::cerr << "Promoted Load To Copy: " << MI);
- MachineFunction &MF = *MBB.getParent();
+ MachineInstr *SSMI = NULL;
+ if (unsigned InReg = Spills.getSpillSlotPhysReg(SS, SSMI)) {
+ DOUT << "Promoted Load To Copy: " << MI;
if (DestReg != InReg) {
MRI->copyRegToReg(MBB, &MI, DestReg, InReg,
MF.getSSARegMap()->getRegClass(VirtReg));
// virtual or needing to clobber any values if it's physical).
NextMII = &MI;
--NextMII; // backtrack to the copy.
+ } else
+ DOUT << "Removing now-noop copy: " << MI;
+
+ // Either way, the live range of the last kill of InReg has been
+ // extended. Remove its kill.
+ bool WasKill = false;
+ if (SSMI) {
+ int UIdx = SSMI->findRegisterUseOperand(InReg, true);
+ if (UIdx != -1) {
+ MachineOperand &MOK = SSMI->getOperand(UIdx);
+ WasKill = MOK.isKill();
+ MOK.unsetIsKill();
+ }
+ }
+ if (NextMII != MBB.end()) {
+ // If NextMII uses InReg and the use is not a two address
+ // operand, mark it killed.
+ int UIdx = NextMII->findRegisterUseOperand(InReg);
+ if (UIdx != -1) {
+ MachineOperand &MOU = NextMII->getOperand(UIdx);
+ if (WasKill) {
+ const TargetInstrDescriptor *NTID =
+ NextMII->getInstrDescriptor();
+ if (UIdx >= NTID->numOperands ||
+ NTID->getOperandConstraint(UIdx, TOI::TIED_TO) == -1)
+ MOU.setIsKill();
+ }
+ Spills.addLastUse(InReg, &(*NextMII));
+ }
}
+
VRM.RemoveFromFoldedVirtMap(&MI);
MBB.erase(&MI);
goto ProcessNextInst;
else {
// If we get here, the store is dead, nuke it now.
assert(VirtRegMap::isMod && "Can't be modref!");
- DEBUG(std::cerr << "Removed dead store:\t" << *MDSI->second);
+ DOUT << "Removed dead store:\t" << *MDSI->second;
MBB.erase(MDSI->second);
VRM.RemoveFromFoldedVirtMap(MDSI->second);
MaybeDeadStores.erase(MDSI);
// 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, false /*don't clobber*/);
+ Spills.addAvailable(StackSlot, &MI, SrcReg, false/*don't clobber*/);
}
}
}
unsigned Src, Dst;
if (TII->isMoveInstr(MI, Src, Dst) && Src == Dst) {
++NumDCE;
- DEBUG(std::cerr << "Removing now-noop copy: " << MI);
+ DOUT << "Removing now-noop copy: " << MI;
+ Spills.removeLastUse(Src, &MI);
MBB.erase(&MI);
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.
assert(DestReg == VirtReg && "Unknown load situation!");
// Otherwise, if it wasn't available, remember that it is now!
- Spills.addAvailable(FrameIdx, DestReg);
+ Spills.addAvailable(FrameIdx, &MI, DestReg);
goto ProcessNextInst;
}
// The only vregs left are stack slot definitions.
int StackSlot = VRM.getStackSlot(VirtReg);
- const TargetRegisterClass *RC =
- MBB.getParent()->getSSARegMap()->getRegClass(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;
- if (i == 0 && TII->isTwoAddrInstr(MI.getOpcode()))
- PhysReg = MI.getOperand(1).getReg();
- else
+ 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);
+ }
+ }
- PhysRegsUsed[PhysReg] = true;
+ MF.setPhysRegUsed(PhysReg);
+ ReusedOperands.markClobbered(PhysReg);
MRI->storeRegToStackSlot(MBB, next(MII), PhysReg, StackSlot, RC);
- DEBUG(std::cerr << "Store:\t" << *next(MII));
+ DOUT << "Store:\t" << *next(MII);
MI.getOperand(i).setReg(PhysReg);
- // 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;
- DEBUG(std::cerr << "Removing now-noop copy: " << MI);
- MBB.erase(&MI);
- VRM.RemoveFromFoldedVirtMap(&MI);
- goto ProcessNextInst;
- }
- }
-
// If there is a dead store to this stack slot, nuke it now.
MachineInstr *&LastStore = MaybeDeadStores[StackSlot];
if (LastStore) {
- DEBUG(std::cerr << "Removed dead store:\t" << *LastStore);
+ DOUT << "Removed dead store:\t" << *LastStore;
++NumDSE;
MBB.erase(LastStore);
VRM.RemoveFromFoldedVirtMap(LastStore);
// in PhysReg.
Spills.ModifyStackSlot(StackSlot);
Spills.ClobberPhysReg(PhysReg);
- Spills.addAvailable(StackSlot, PhysReg);
+ Spills.addAvailable(StackSlot, LastStore, PhysReg);
++NumStores;
+
+ // 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;
+ Spills.removeLastUse(Src, &MI);
+ MBB.erase(&MI);
+ VRM.RemoveFromFoldedVirtMap(&MI);
+ goto ProcessNextInst;
+ }
+ }
}
}
ProcessNextInst:
projects / oota-llvm.git / blobdiff