#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetSubtargetInfo.h"
using namespace llvm;
#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, LaneBitmask LaneMask) {
+ for (MCRegUnitMaskIterator RUI(Reg, TRI); RUI.isValid(); ++RUI) {
+ LaneBitmask UnitMask = (*RUI).second;
+ if (UnitMask == 0 || (LaneMask & UnitMask) != 0)
+ RegUnitsAvailable.reset((*RUI).first);
+ }
}
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);
+ for (const auto &LI : MBB->liveins())
+ setRegUsed(LI.PhysReg, LI.LaneMask);
// Pristine CSRs are also unavailable.
- BitVector PR = MBB->getParent()->getFrameInfo()->getPristineRegs(MBB);
+ const MachineFunction &MF = *MBB->getParent();
+ BitVector PR = MF.getFrameInfo()->getPristineRegs(MF);
for (int I = PR.find_first(); I>0; I = PR.find_next(I))
- setUsed(I);
+ setRegUsed(I);
}
void RegScavenger::enterBasicBlock(MachineBasicBlock *mbb) {
MachineFunction &MF = *mbb->getParent();
- const TargetMachine &TM = MF.getTarget();
- TII = TM.getSubtargetImpl()->getInstrInfo();
- TRI = TM.getSubtargetImpl()->getRegisterInfo();
+ TII = MF.getSubtarget().getInstrInfo();
+ TRI = MF.getSubtarget().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() {
// Find out which registers are early clobbered, killed, defined, and marked
// def-dead in this instruction.
- // FIXME: The scavenger is not predication aware. If the instruction is
- // 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.
+ KillRegUnits |= TmpRegUnits;
+ }
if (!MO.isReg())
continue;
unsigned Reg = MO.getReg();
// Ignore undef uses.
if (MO.isUndef())
continue;
- if (!isPred && MO.isKill())
- addRegWithSubRegs(KillRegs, Reg);
+ if (MO.isKill())
+ addRegUnits(KillRegUnits, Reg);
} else {
assert(MO.isDef());
- if (!isPred && MO.isDead())
- addRegWithSubRegs(KillRegs, Reg);
+ if (MO.isDead())
+ 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;
}
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