///
/// That function will return NULL if the virtual registers have incompatible
/// constraints.
+ ///
+ /// Note that if ToReg is a physical register the function will replace and
+ /// apply sub registers to ToReg in order to obtain a final/proper physical
+ /// register.
void replaceRegWith(unsigned FromReg, unsigned ToReg);
-
+
/// getVRegDef - Return the machine instr that defines the specified virtual
/// register or null if none is found. This assumes that the code is in SSA
/// form, so there should only be one definition.
MachineRegisterInfo* MRI;
MachineBasicBlock *MBB;
MachineBasicBlock::iterator MBBI;
- unsigned NumPhysRegs;
+ unsigned NumRegUnits;
/// Tracking - True if RegScavenger is currently tracking the liveness of
/// registers.
/// A vector of information on scavenged registers.
SmallVector<ScavengedInfo, 2> Scavenged;
- /// CalleeSavedrRegs - A bitvector of callee saved registers for the target.
- ///
- BitVector CalleeSavedRegs;
-
- /// RegsAvailable - The current state of all the physical registers immediately
- /// before MBBI. One bit per physical register. If bit is set that means it's
- /// available, unset means the register is currently being used.
- BitVector RegsAvailable;
+ /// RegUnitsAvailable - The current state of each reg unit immediatelly
+ /// before MBBI. One bit per register unit. If bit is not set it means any
+ /// register containing that register unit is currently being used.
+ BitVector RegUnitsAvailable;
// These BitVectors are only used internally to forward(). They are members
// to avoid frequent reallocations.
- BitVector KillRegs, DefRegs;
+ BitVector KillRegUnits, DefRegUnits;
+ BitVector TmpRegUnits;
public:
RegScavenger()
- : MBB(nullptr), NumPhysRegs(0), Tracking(false) {}
+ : MBB(nullptr), NumRegUnits(0), Tracking(false) {}
/// enterBasicBlock - Start tracking liveness from the begin of the specific
/// basic block.
MachineBasicBlock::iterator getCurrentPosition() const {
return MBBI;
}
-
- /// getRegsUsed - return all registers currently in use in used.
- void getRegsUsed(BitVector &used, bool includeReserved);
+
+ /// isRegUsed - return if a specific register is currently used.
+ bool isRegUsed(unsigned Reg, bool includeReserved = true) const;
/// getRegsAvailable - Return all available registers in the register class
/// in Mask.
return scavengeRegister(RegClass, MBBI, SPAdj);
}
- /// setUsed - Tell the scavenger a register is used.
+ /// setRegUsed - Tell the scavenger a register is used.
///
- void setUsed(unsigned Reg);
+ void setRegUsed(unsigned Reg);
private:
/// isReserved - Returns true if a register is reserved. It is never "unused".
bool isReserved(unsigned Reg) const { return MRI->isReserved(Reg); }
- /// isUsed - Test if a register is currently being used. When called by the
- /// isAliasUsed function, we only check isReserved if this is the original
- /// register, not an alias register.
+ /// setUsed / setUnused - Mark the state of one or a number of register units.
///
- bool isUsed(unsigned Reg, bool CheckReserved = true) const {
- return !RegsAvailable.test(Reg) || (CheckReserved && isReserved(Reg));
+ void setUsed(BitVector &RegUnits) {
+ RegUnitsAvailable.reset(RegUnits);
}
-
- /// isAliasUsed - Is Reg or an alias currently in use?
- bool isAliasUsed(unsigned Reg) const;
-
- /// setUsed / setUnused - Mark the state of one or a number of registers.
- ///
- void setUsed(BitVector &Regs) {
- RegsAvailable.reset(Regs);
- }
- void setUnused(BitVector &Regs) {
- RegsAvailable |= Regs;
+ void setUnused(BitVector &RegUnits) {
+ RegUnitsAvailable |= RegUnits;
}
- /// Processes the current instruction and fill the KillRegs and DefRegs bit
- /// vectors.
+ /// Processes the current instruction and fill the KillRegUnits and
+ /// DefRegUnits bit vectors.
void determineKillsAndDefs();
-
- /// Add Reg and all its sub-registers to BV.
- void addRegWithSubRegs(BitVector &BV, unsigned Reg);
-
+
+ /// Add all Reg Units that Reg contains to BV.
+ void addRegUnits(BitVector &BV, unsigned Reg);
+
/// findSurvivorReg - Return the candidate register that is unused for the
/// longest after StartMI. UseMI is set to the instruction where the search
/// stopped.
RS->enterBasicBlock(CurMBB);
if (!CurMBB->empty())
RS->forward(std::prev(CurMBB->end()));
- BitVector RegsLiveAtExit(TRI->getNumRegs());
- RS->getRegsUsed(RegsLiveAtExit, false);
- for (unsigned int i = 0, e = TRI->getNumRegs(); i != e; i++)
- if (RegsLiveAtExit[i])
+ for (unsigned int i = 1, e = TRI->getNumRegs(); i != e; i++)
+ if (RS->isRegUsed(i, false))
NewMBB->addLiveIn(i);
}
}
/// replaceRegWith - Replace all instances of FromReg with ToReg in the
/// machine function. This is like llvm-level X->replaceAllUsesWith(Y),
/// except that it also changes any definitions of the register as well.
+/// If ToReg is a physical register we apply the sub register to obtain the
+/// final/proper physical register.
void MachineRegisterInfo::replaceRegWith(unsigned FromReg, unsigned ToReg) {
assert(FromReg != ToReg && "Cannot replace a reg with itself");
+ const TargetRegisterInfo *TRI = getTargetRegisterInfo();
+
// TODO: This could be more efficient by bulk changing the operands.
for (reg_iterator I = reg_begin(FromReg), E = reg_end(); I != E; ) {
MachineOperand &O = *I;
++I;
- O.setReg(ToReg);
+ if (TargetRegisterInfo::isPhysicalRegister(ToReg)) {
+ O.substPhysReg(ToReg, *TRI);
+ } else {
+ O.setReg(ToReg);
+ }
}
}
-
/// getVRegDef - Return the machine instr that defines the specified virtual
/// register or null if none is found. This assumes that the code is in SSA
/// form, so there should only be one definition.
/// FIXME: Iterating over the instruction stream is unnecessary. We can simply
/// iterate over the vreg use list, which at this point only contains machine
/// operands for which eliminateFrameIndex need a new scratch reg.
-void PEI::scavengeFrameVirtualRegs(MachineFunction &Fn) {
+void
+PEI::scavengeFrameVirtualRegs(MachineFunction &Fn) {
// Run through the instructions and find any virtual registers.
for (MachineFunction::iterator BB = Fn.begin(),
E = Fn.end(); BB != E; ++BB) {
// Replace this reference to the virtual register with the
// scratch register.
assert (ScratchReg && "Missing scratch register!");
+ MachineRegisterInfo &MRI = Fn.getRegInfo();
Fn.getRegInfo().replaceRegWith(Reg, ScratchReg);
+
+ // Make sure MRI now accounts this register as used.
+ MRI.setPhysRegUsed(ScratchReg);
// Because this instruction was processed by the RS before this
// register was allocated, make sure that the RS now records the
// register as being used.
- RS->setUsed(ScratchReg);
+ RS->setRegUsed(ScratchReg);
}
}
#define DEBUG_TYPE "reg-scavenging"
-/// setUsed - Set the register and its sub-registers as being used.
-void RegScavenger::setUsed(unsigned Reg) {
- for (MCSubRegIterator SubRegs(Reg, TRI, /*IncludeSelf=*/true);
- SubRegs.isValid(); ++SubRegs)
- RegsAvailable.reset(*SubRegs);
-}
-
-bool RegScavenger::isAliasUsed(unsigned Reg) const {
- for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
- if (isUsed(*AI, *AI == Reg))
- return true;
- return false;
+/// setUsed - Set the register units of this register as used.
+void RegScavenger::setRegUsed(unsigned Reg) {
+ for (MCRegUnitIterator RUI(Reg, TRI); RUI.isValid(); ++RUI)
+ RegUnitsAvailable.reset(*RUI);
}
void RegScavenger::initRegState() {
I->Restore = nullptr;
}
- // All registers started out unused.
- RegsAvailable.set();
+ // All register units start out unused.
+ RegUnitsAvailable.set();
if (!MBB)
return;
// Live-in registers are in use.
for (MachineBasicBlock::livein_iterator I = MBB->livein_begin(),
E = MBB->livein_end(); I != E; ++I)
- setUsed(*I);
+ setRegUsed(*I);
// Pristine CSRs are also unavailable.
BitVector PR = MBB->getParent()->getFrameInfo()->getPristineRegs(MBB);
for (int I = PR.find_first(); I>0; I = PR.find_next(I))
- setUsed(I);
+ setRegUsed(I);
}
void RegScavenger::enterBasicBlock(MachineBasicBlock *mbb) {
TRI = TM.getSubtargetImpl()->getRegisterInfo();
MRI = &MF.getRegInfo();
- assert((NumPhysRegs == 0 || NumPhysRegs == TRI->getNumRegs()) &&
+ assert((NumRegUnits == 0 || NumRegUnits == TRI->getNumRegUnits()) &&
"Target changed?");
// It is not possible to use the register scavenger after late optimization
// Self-initialize.
if (!MBB) {
- NumPhysRegs = TRI->getNumRegs();
- RegsAvailable.resize(NumPhysRegs);
- KillRegs.resize(NumPhysRegs);
- DefRegs.resize(NumPhysRegs);
-
- // Create callee-saved registers bitvector.
- CalleeSavedRegs.resize(NumPhysRegs);
- const MCPhysReg *CSRegs = TRI->getCalleeSavedRegs(&MF);
- if (CSRegs != nullptr)
- for (unsigned i = 0; CSRegs[i]; ++i)
- CalleeSavedRegs.set(CSRegs[i]);
+ NumRegUnits = TRI->getNumRegUnits();
+ RegUnitsAvailable.resize(NumRegUnits);
+ KillRegUnits.resize(NumRegUnits);
+ DefRegUnits.resize(NumRegUnits);
+ TmpRegUnits.resize(NumRegUnits);
}
MBB = mbb;
Tracking = false;
}
-void RegScavenger::addRegWithSubRegs(BitVector &BV, unsigned Reg) {
- for (MCSubRegIterator SubRegs(Reg, TRI, /*IncludeSelf=*/true);
- SubRegs.isValid(); ++SubRegs)
- BV.set(*SubRegs);
+void RegScavenger::addRegUnits(BitVector &BV, unsigned Reg) {
+ for (MCRegUnitIterator RUI(Reg, TRI); RUI.isValid(); ++RUI)
+ BV.set(*RUI);
}
void RegScavenger::determineKillsAndDefs() {
// predicated, conservatively assume "kill" markers do not actually kill the
// register. Similarly ignores "dead" markers.
bool isPred = TII->isPredicated(MI);
- KillRegs.reset();
- DefRegs.reset();
+ KillRegUnits.reset();
+ DefRegUnits.reset();
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
- if (MO.isRegMask())
- (isPred ? DefRegs : KillRegs).setBitsNotInMask(MO.getRegMask());
+ if (MO.isRegMask()) {
+
+ TmpRegUnits.clear();
+ for (unsigned RU = 0, RUEnd = TRI->getNumRegUnits(); RU != RUEnd; ++RU) {
+ for (MCRegUnitRootIterator RURI(RU, TRI); RURI.isValid(); ++RURI) {
+ if (MO.clobbersPhysReg(*RURI)) {
+ TmpRegUnits.set(RU);
+ break;
+ }
+ }
+ }
+
+ // Apply the mask.
+ (isPred ? DefRegUnits : KillRegUnits) |= TmpRegUnits;
+ }
if (!MO.isReg())
continue;
unsigned Reg = MO.getReg();
if (MO.isUndef())
continue;
if (!isPred && MO.isKill())
- addRegWithSubRegs(KillRegs, Reg);
+ addRegUnits(KillRegUnits, Reg);
} else {
assert(MO.isDef());
if (!isPred && MO.isDead())
- addRegWithSubRegs(KillRegs, Reg);
+ addRegUnits(KillRegUnits, Reg);
else
- addRegWithSubRegs(DefRegs, Reg);
+ addRegUnits(DefRegUnits, Reg);
}
}
}
determineKillsAndDefs();
// Commit the changes.
- setUsed(KillRegs);
- setUnused(DefRegs);
+ setUsed(KillRegUnits);
+ setUnused(DefRegUnits);
}
if (MBBI == MBB->begin()) {
if (MO.isUse()) {
if (MO.isUndef())
continue;
- if (!isUsed(Reg)) {
+ if (!isRegUsed(Reg)) {
// Check if it's partial live: e.g.
// D0 = insert_subreg D0<undef>, S0
// ... D0
// insert_subreg around causes both correctness and performance issues.
bool SubUsed = false;
for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
- if (isUsed(*SubRegs)) {
+ if (isRegUsed(*SubRegs)) {
SubUsed = true;
break;
}
- if (!SubUsed) {
+ bool SuperUsed = false;
+ for (MCSuperRegIterator SR(Reg, TRI); SR.isValid(); ++SR) {
+ if (isRegUsed(*SR)) {
+ SuperUsed = true;
+ break;
+ }
+ }
+ if (!SubUsed && !SuperUsed) {
MBB->getParent()->verify(nullptr, "In Register Scavenger");
llvm_unreachable("Using an undefined register!");
}
(void)SubUsed;
+ (void)SuperUsed;
}
} else {
assert(MO.isDef());
#endif // NDEBUG
// Commit the changes.
- setUnused(KillRegs);
- setUsed(DefRegs);
+ setUnused(KillRegUnits);
+ setUsed(DefRegUnits);
}
-void RegScavenger::getRegsUsed(BitVector &used, bool includeReserved) {
- used = RegsAvailable;
- used.flip();
- if (includeReserved)
- used |= MRI->getReservedRegs();
- else
- used.reset(MRI->getReservedRegs());
+bool RegScavenger::isRegUsed(unsigned Reg, bool includeReserved) const {
+ if (includeReserved && isReserved(Reg))
+ return true;
+ for (MCRegUnitIterator RUI(Reg, TRI); RUI.isValid(); ++RUI)
+ if (!RegUnitsAvailable.test(*RUI))
+ return true;
+ return false;
}
unsigned RegScavenger::FindUnusedReg(const TargetRegisterClass *RC) const {
for (TargetRegisterClass::iterator I = RC->begin(), E = RC->end();
I != E; ++I)
- if (!isAliasUsed(*I)) {
+ if (!isRegUsed(*I)) {
DEBUG(dbgs() << "Scavenger found unused reg: " << TRI->getName(*I) <<
"\n");
return *I;
BitVector Mask(TRI->getNumRegs());
for (TargetRegisterClass::iterator I = RC->begin(), E = RC->end();
I != E; ++I)
- if (!isAliasUsed(*I))
+ if (!isRegUsed(*I))
Mask.set(*I);
return Mask;
}
/// findSurvivorReg - Return the candidate register that is unused for the
-/// longest after StargMII. UseMI is set to the instruction where the search
+/// longest after StartMII. UseMI is set to the instruction where the search
/// stopped.
///
/// No more than InstrLimit instructions are inspected.
}
// Try to find a register that's unused if there is one, as then we won't
- // have to spill. Search explicitly rather than masking out based on
- // RegsAvailable, as RegsAvailable does not take aliases into account.
- // That's what getRegsAvailable() is for.
+ // have to spill.
BitVector Available = getRegsAvailable(RC);
Available &= Candidates;
if (Available.any())
unsigned SReg = findSurvivorReg(I, Candidates, 25, UseMI);
// If we found an unused register there is no reason to spill it.
- if (!isAliasUsed(SReg)) {
+ if (!isRegUsed(SReg)) {
DEBUG(dbgs() << "Scavenged register: " << TRI->getName(SReg) << "\n");
return SReg;
}
RS->enterBasicBlock(PredBB);
if (!PredBB->empty())
RS->forward(std::prev(PredBB->end()));
- BitVector RegsLiveAtExit(TRI->getNumRegs());
- RS->getRegsUsed(RegsLiveAtExit, false);
for (MachineBasicBlock::livein_iterator I = TailBB->livein_begin(),
E = TailBB->livein_end(); I != E; ++I) {
- if (!RegsLiveAtExit[*I])
+ if (!RS->isRegUsed(*I, false))
// If a register is previously livein to the tail but it's not live
// at the end of predecessor BB, then it should be added to its
// livein list.
MachineBasicBlock &MBB = *MI.getParent();
DebugLoc dl = MI.getDebugLoc();
unsigned ScratchOffset = RS->scavengeRegister(&XCore::GRRegsRegClass, II, 0);
- RS->setUsed(ScratchOffset);
+ RS->setRegUsed(ScratchOffset);
TII.loadImmediate(MBB, II, ScratchOffset, Offset);
switch (MI.getOpcode()) {
unsigned ScratchBase;
if (OpCode==XCore::STWFI) {
ScratchBase = RS->scavengeRegister(&XCore::GRRegsRegClass, II, 0);
- RS->setUsed(ScratchBase);
+ RS->setRegUsed(ScratchBase);
} else
ScratchBase = Reg;
BuildMI(MBB, II, dl, TII.get(XCore::LDAWSP_ru6), ScratchBase).addImm(0);
unsigned ScratchOffset = RS->scavengeRegister(&XCore::GRRegsRegClass, II, 0);
- RS->setUsed(ScratchOffset);
+ RS->setRegUsed(ScratchOffset);
TII.loadImmediate(MBB, II, ScratchOffset, Offset);
switch (OpCode) {
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