STATISTIC(NumReSchedDowns, "Number of instructions re-scheduled down");
namespace {
- class TwoAddressInstructionPass : public MachineFunctionPass {
- MachineFunction *MF;
- const TargetInstrInfo *TII;
- const TargetRegisterInfo *TRI;
- const InstrItineraryData *InstrItins;
- MachineRegisterInfo *MRI;
- LiveVariables *LV;
- SlotIndexes *Indexes;
- LiveIntervals *LIS;
- AliasAnalysis *AA;
- CodeGenOpt::Level OptLevel;
-
- // DistanceMap - Keep track the distance of a MI from the start of the
- // current basic block.
- DenseMap<MachineInstr*, unsigned> DistanceMap;
-
- // SrcRegMap - A map from virtual registers to physical registers which
- // are likely targets to be coalesced to due to copies from physical
- // registers to virtual registers. e.g. v1024 = move r0.
- DenseMap<unsigned, unsigned> SrcRegMap;
-
- // DstRegMap - A map from virtual registers to physical registers which
- // are likely targets to be coalesced to due to copies to physical
- // registers from virtual registers. e.g. r1 = move v1024.
- DenseMap<unsigned, unsigned> DstRegMap;
-
- /// RegSequences - Keep track the list of REG_SEQUENCE instructions seen
- /// during the initial walk of the machine function.
- SmallVector<MachineInstr*, 16> RegSequences;
-
- bool Sink3AddrInstruction(MachineBasicBlock *MBB, MachineInstr *MI,
- unsigned Reg,
- MachineBasicBlock::iterator OldPos);
-
- bool NoUseAfterLastDef(unsigned Reg, MachineBasicBlock *MBB, unsigned Dist,
- unsigned &LastDef);
-
- bool isProfitableToCommute(unsigned regA, unsigned regB, unsigned regC,
- MachineInstr *MI, MachineBasicBlock *MBB,
- unsigned Dist);
+class TwoAddressInstructionPass : public MachineFunctionPass {
+ MachineFunction *MF;
+ const TargetInstrInfo *TII;
+ const TargetRegisterInfo *TRI;
+ const InstrItineraryData *InstrItins;
+ MachineRegisterInfo *MRI;
+ LiveVariables *LV;
+ SlotIndexes *Indexes;
+ LiveIntervals *LIS;
+ AliasAnalysis *AA;
+ CodeGenOpt::Level OptLevel;
+
+ // The current basic block being processed.
+ MachineBasicBlock *MBB;
+
+ // DistanceMap - Keep track the distance of a MI from the start of the
+ // current basic block.
+ DenseMap<MachineInstr*, unsigned> DistanceMap;
+
+ // Set of already processed instructions in the current block.
+ SmallPtrSet<MachineInstr*, 8> Processed;
- bool CommuteInstruction(MachineBasicBlock::iterator &mi,
- MachineFunction::iterator &mbbi,
- unsigned RegB, unsigned RegC, unsigned Dist);
+ // SrcRegMap - A map from virtual registers to physical registers which are
+ // likely targets to be coalesced to due to copies from physical registers to
+ // virtual registers. e.g. v1024 = move r0.
+ DenseMap<unsigned, unsigned> SrcRegMap;
- bool isProfitableToConv3Addr(unsigned RegA, unsigned RegB);
+ // DstRegMap - A map from virtual registers to physical registers which are
+ // likely targets to be coalesced to due to copies to physical registers from
+ // virtual registers. e.g. r1 = move v1024.
+ DenseMap<unsigned, unsigned> DstRegMap;
- bool ConvertInstTo3Addr(MachineBasicBlock::iterator &mi,
- MachineBasicBlock::iterator &nmi,
- MachineFunction::iterator &mbbi,
- unsigned RegA, unsigned RegB, unsigned Dist);
+ /// RegSequences - Keep track the list of REG_SEQUENCE instructions seen
+ /// during the initial walk of the machine function.
+ SmallVector<MachineInstr*, 16> RegSequences;
- bool isDefTooClose(unsigned Reg, unsigned Dist,
- MachineInstr *MI, MachineBasicBlock *MBB);
+ bool sink3AddrInstruction(MachineInstr *MI, unsigned Reg,
+ MachineBasicBlock::iterator OldPos);
- bool RescheduleMIBelowKill(MachineBasicBlock *MBB,
- MachineBasicBlock::iterator &mi,
- MachineBasicBlock::iterator &nmi,
- unsigned Reg);
- bool RescheduleKillAboveMI(MachineBasicBlock *MBB,
- MachineBasicBlock::iterator &mi,
- MachineBasicBlock::iterator &nmi,
- unsigned Reg);
+ bool noUseAfterLastDef(unsigned Reg, unsigned Dist, unsigned &LastDef);
- bool TryInstructionTransform(MachineBasicBlock::iterator &mi,
- MachineBasicBlock::iterator &nmi,
- MachineFunction::iterator &mbbi,
- unsigned SrcIdx, unsigned DstIdx,
- unsigned Dist,
- SmallPtrSet<MachineInstr*, 8> &Processed);
+ bool isProfitableToCommute(unsigned regA, unsigned regB, unsigned regC,
+ MachineInstr *MI, unsigned Dist);
- void ScanUses(unsigned DstReg, MachineBasicBlock *MBB,
- SmallPtrSet<MachineInstr*, 8> &Processed);
+ bool commuteInstruction(MachineBasicBlock::iterator &mi,
+ unsigned RegB, unsigned RegC, unsigned Dist);
- void ProcessCopy(MachineInstr *MI, MachineBasicBlock *MBB,
- SmallPtrSet<MachineInstr*, 8> &Processed);
+ bool isProfitableToConv3Addr(unsigned RegA, unsigned RegB);
- typedef SmallVector<std::pair<unsigned, unsigned>, 4> TiedPairList;
- typedef SmallDenseMap<unsigned, TiedPairList> TiedOperandMap;
- bool collectTiedOperands(MachineInstr *MI, TiedOperandMap&);
- void processTiedPairs(MachineInstr *MI, TiedPairList&, unsigned &Dist);
+ bool convertInstTo3Addr(MachineBasicBlock::iterator &mi,
+ MachineBasicBlock::iterator &nmi,
+ unsigned RegA, unsigned RegB, unsigned Dist);
- void CoalesceExtSubRegs(SmallVector<unsigned,4> &Srcs, unsigned DstReg);
+ bool isDefTooClose(unsigned Reg, unsigned Dist, MachineInstr *MI);
- /// EliminateRegSequences - Eliminate REG_SEQUENCE instructions as part
- /// of the de-ssa process. This replaces sources of REG_SEQUENCE as
- /// sub-register references of the register defined by REG_SEQUENCE.
- bool EliminateRegSequences();
+ bool rescheduleMIBelowKill(MachineBasicBlock::iterator &mi,
+ MachineBasicBlock::iterator &nmi,
+ unsigned Reg);
+ bool rescheduleKillAboveMI(MachineBasicBlock::iterator &mi,
+ MachineBasicBlock::iterator &nmi,
+ unsigned Reg);
- public:
- static char ID; // Pass identification, replacement for typeid
- TwoAddressInstructionPass() : MachineFunctionPass(ID) {
- initializeTwoAddressInstructionPassPass(*PassRegistry::getPassRegistry());
- }
+ bool tryInstructionTransform(MachineBasicBlock::iterator &mi,
+ MachineBasicBlock::iterator &nmi,
+ unsigned SrcIdx, unsigned DstIdx,
+ unsigned Dist);
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesCFG();
- AU.addRequired<AliasAnalysis>();
- AU.addPreserved<LiveVariables>();
- AU.addPreserved<SlotIndexes>();
- AU.addPreserved<LiveIntervals>();
- AU.addPreservedID(MachineLoopInfoID);
- AU.addPreservedID(MachineDominatorsID);
- MachineFunctionPass::getAnalysisUsage(AU);
- }
+ void scanUses(unsigned DstReg);
- /// runOnMachineFunction - Pass entry point.
- bool runOnMachineFunction(MachineFunction&);
- };
-}
+ void processCopy(MachineInstr *MI);
+
+ typedef SmallVector<std::pair<unsigned, unsigned>, 4> TiedPairList;
+ typedef SmallDenseMap<unsigned, TiedPairList> TiedOperandMap;
+ bool collectTiedOperands(MachineInstr *MI, TiedOperandMap&);
+ void processTiedPairs(MachineInstr *MI, TiedPairList&, unsigned &Dist);
+
+ /// eliminateRegSequences - Eliminate REG_SEQUENCE instructions as part of
+ /// the de-ssa process. This replaces sources of REG_SEQUENCE as sub-register
+ /// references of the register defined by REG_SEQUENCE.
+ bool eliminateRegSequences();
+
+public:
+ static char ID; // Pass identification, replacement for typeid
+ TwoAddressInstructionPass() : MachineFunctionPass(ID) {
+ initializeTwoAddressInstructionPassPass(*PassRegistry::getPassRegistry());
+ }
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesCFG();
+ AU.addRequired<AliasAnalysis>();
+ AU.addPreserved<LiveVariables>();
+ AU.addPreserved<SlotIndexes>();
+ AU.addPreserved<LiveIntervals>();
+ AU.addPreservedID(MachineLoopInfoID);
+ AU.addPreservedID(MachineDominatorsID);
+ MachineFunctionPass::getAnalysisUsage(AU);
+ }
+
+ /// runOnMachineFunction - Pass entry point.
+ bool runOnMachineFunction(MachineFunction&);
+};
+} // end anonymous namespace
char TwoAddressInstructionPass::ID = 0;
INITIALIZE_PASS_BEGIN(TwoAddressInstructionPass, "twoaddressinstruction",
char &llvm::TwoAddressInstructionPassID = TwoAddressInstructionPass::ID;
-/// Sink3AddrInstruction - A two-address instruction has been converted to a
+/// sink3AddrInstruction - A two-address instruction has been converted to a
/// three-address instruction to avoid clobbering a register. Try to sink it
/// past the instruction that would kill the above mentioned register to reduce
/// register pressure.
-bool TwoAddressInstructionPass::Sink3AddrInstruction(MachineBasicBlock *MBB,
- MachineInstr *MI, unsigned SavedReg,
- MachineBasicBlock::iterator OldPos) {
+bool TwoAddressInstructionPass::
+sink3AddrInstruction(MachineInstr *MI, unsigned SavedReg,
+ MachineBasicBlock::iterator OldPos) {
// FIXME: Shouldn't we be trying to do this before we three-addressify the
// instruction? After this transformation is done, we no longer need
// the instruction to be in three-address form.
return true;
}
-/// NoUseAfterLastDef - Return true if there are no intervening uses between the
+/// noUseAfterLastDef - Return true if there are no intervening uses between the
/// last instruction in the MBB that defines the specified register and the
/// two-address instruction which is being processed. It also returns the last
/// def location by reference
-bool TwoAddressInstructionPass::NoUseAfterLastDef(unsigned Reg,
- MachineBasicBlock *MBB, unsigned Dist,
- unsigned &LastDef) {
+bool TwoAddressInstructionPass::noUseAfterLastDef(unsigned Reg, unsigned Dist,
+ unsigned &LastDef) {
LastDef = 0;
unsigned LastUse = Dist;
for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(Reg),
/// isProfitableToCommute - Return true if it's potentially profitable to commute
/// the two-address instruction that's being processed.
bool
-TwoAddressInstructionPass::isProfitableToCommute(unsigned regA, unsigned regB,
- unsigned regC,
- MachineInstr *MI, MachineBasicBlock *MBB,
- unsigned Dist) {
+TwoAddressInstructionPass::
+isProfitableToCommute(unsigned regA, unsigned regB, unsigned regC,
+ MachineInstr *MI, unsigned Dist) {
if (OptLevel == CodeGenOpt::None)
return false;
// If there is a use of regC between its last def (could be livein) and this
// instruction, then bail.
unsigned LastDefC = 0;
- if (!NoUseAfterLastDef(regC, MBB, Dist, LastDefC))
+ if (!noUseAfterLastDef(regC, Dist, LastDefC))
return false;
// If there is a use of regB between its last def (could be livein) and this
// instruction, then go ahead and make this transformation.
unsigned LastDefB = 0;
- if (!NoUseAfterLastDef(regB, MBB, Dist, LastDefB))
+ if (!noUseAfterLastDef(regB, Dist, LastDefB))
return true;
// Since there are no intervening uses for both registers, then commute
return LastDefB && LastDefC && LastDefC > LastDefB;
}
-/// CommuteInstruction - Commute a two-address instruction and update the basic
+/// commuteInstruction - Commute a two-address instruction and update the basic
/// block, distance map, and live variables if needed. Return true if it is
/// successful.
-bool
-TwoAddressInstructionPass::CommuteInstruction(MachineBasicBlock::iterator &mi,
- MachineFunction::iterator &mbbi,
- unsigned RegB, unsigned RegC, unsigned Dist) {
+bool TwoAddressInstructionPass::
+commuteInstruction(MachineBasicBlock::iterator &mi,
+ unsigned RegB, unsigned RegC, unsigned Dist) {
MachineInstr *MI = mi;
DEBUG(dbgs() << "2addr: COMMUTING : " << *MI);
MachineInstr *NewMI = TII->commuteInstruction(MI);
if (Indexes)
Indexes->replaceMachineInstrInMaps(MI, NewMI);
- mbbi->insert(mi, NewMI); // Insert the new inst
- mbbi->erase(mi); // Nuke the old inst.
+ MBB->insert(mi, NewMI); // Insert the new inst
+ MBB->erase(mi); // Nuke the old inst.
mi = NewMI;
DistanceMap.insert(std::make_pair(NewMI, Dist));
}
return (ToRegA && !regsAreCompatible(FromRegB, ToRegA, TRI));
}
-/// ConvertInstTo3Addr - Convert the specified two-address instruction into a
+/// convertInstTo3Addr - Convert the specified two-address instruction into a
/// three address one. Return true if this transformation was successful.
bool
-TwoAddressInstructionPass::ConvertInstTo3Addr(MachineBasicBlock::iterator &mi,
+TwoAddressInstructionPass::convertInstTo3Addr(MachineBasicBlock::iterator &mi,
MachineBasicBlock::iterator &nmi,
- MachineFunction::iterator &mbbi,
unsigned RegA, unsigned RegB,
unsigned Dist) {
- MachineInstr *NewMI = TII->convertToThreeAddress(mbbi, mi, LV);
- if (NewMI) {
- DEBUG(dbgs() << "2addr: CONVERTING 2-ADDR: " << *mi);
- DEBUG(dbgs() << "2addr: TO 3-ADDR: " << *NewMI);
- bool Sunk = false;
+ // FIXME: Why does convertToThreeAddress() need an iterator reference?
+ MachineFunction::iterator MFI = MBB;
+ MachineInstr *NewMI = TII->convertToThreeAddress(MFI, mi, LV);
+ assert(MBB == MFI && "convertToThreeAddress changed iterator reference");
+ if (!NewMI)
+ return false;
- if (Indexes)
- Indexes->replaceMachineInstrInMaps(mi, NewMI);
+ DEBUG(dbgs() << "2addr: CONVERTING 2-ADDR: " << *mi);
+ DEBUG(dbgs() << "2addr: TO 3-ADDR: " << *NewMI);
+ bool Sunk = false;
- if (NewMI->findRegisterUseOperand(RegB, false, TRI))
- // FIXME: Temporary workaround. If the new instruction doesn't
- // uses RegB, convertToThreeAddress must have created more
- // then one instruction.
- Sunk = Sink3AddrInstruction(mbbi, NewMI, RegB, mi);
+ if (Indexes)
+ Indexes->replaceMachineInstrInMaps(mi, NewMI);
- mbbi->erase(mi); // Nuke the old inst.
+ if (NewMI->findRegisterUseOperand(RegB, false, TRI))
+ // FIXME: Temporary workaround. If the new instruction doesn't
+ // uses RegB, convertToThreeAddress must have created more
+ // then one instruction.
+ Sunk = sink3AddrInstruction(NewMI, RegB, mi);
- if (!Sunk) {
- DistanceMap.insert(std::make_pair(NewMI, Dist));
- mi = NewMI;
- nmi = llvm::next(mi);
- }
+ MBB->erase(mi); // Nuke the old inst.
- // Update source and destination register maps.
- SrcRegMap.erase(RegA);
- DstRegMap.erase(RegB);
- return true;
+ if (!Sunk) {
+ DistanceMap.insert(std::make_pair(NewMI, Dist));
+ mi = NewMI;
+ nmi = llvm::next(mi);
}
- return false;
+ // Update source and destination register maps.
+ SrcRegMap.erase(RegA);
+ DstRegMap.erase(RegB);
+ return true;
}
-/// ScanUses - Scan forward recursively for only uses, update maps if the use
+/// scanUses - Scan forward recursively for only uses, update maps if the use
/// is a copy or a two-address instruction.
void
-TwoAddressInstructionPass::ScanUses(unsigned DstReg, MachineBasicBlock *MBB,
- SmallPtrSet<MachineInstr*, 8> &Processed) {
+TwoAddressInstructionPass::scanUses(unsigned DstReg) {
SmallVector<unsigned, 4> VirtRegPairs;
bool IsDstPhys;
bool IsCopy = false;
}
}
-/// ProcessCopy - If the specified instruction is not yet processed, process it
+/// processCopy - If the specified instruction is not yet processed, process it
/// if it's a copy. For a copy instruction, we find the physical registers the
/// source and destination registers might be mapped to. These are kept in
/// point-to maps used to determine future optimizations. e.g.
/// coalesced to r0 (from the input side). v1025 is mapped to r1. v1026 is
/// potentially joined with r1 on the output side. It's worthwhile to commute
/// 'add' to eliminate a copy.
-void TwoAddressInstructionPass::ProcessCopy(MachineInstr *MI,
- MachineBasicBlock *MBB,
- SmallPtrSet<MachineInstr*, 8> &Processed) {
+void TwoAddressInstructionPass::processCopy(MachineInstr *MI) {
if (Processed.count(MI))
return;
assert(SrcRegMap[DstReg] == SrcReg &&
"Can't map to two src physical registers!");
- ScanUses(DstReg, MBB, Processed);
+ scanUses(DstReg);
}
Processed.insert(MI);
return;
}
-/// RescheduleMIBelowKill - If there is one more local instruction that reads
+/// rescheduleMIBelowKill - If there is one more local instruction that reads
/// 'Reg' and it kills 'Reg, consider moving the instruction below the kill
/// instruction in order to eliminate the need for the copy.
-bool
-TwoAddressInstructionPass::RescheduleMIBelowKill(MachineBasicBlock *MBB,
- MachineBasicBlock::iterator &mi,
- MachineBasicBlock::iterator &nmi,
- unsigned Reg) {
+bool TwoAddressInstructionPass::
+rescheduleMIBelowKill(MachineBasicBlock::iterator &mi,
+ MachineBasicBlock::iterator &nmi,
+ unsigned Reg) {
// Bail immediately if we don't have LV available. We use it to find kills
// efficiently.
if (!LV)
/// isDefTooClose - Return true if the re-scheduling will put the given
/// instruction too close to the defs of its register dependencies.
bool TwoAddressInstructionPass::isDefTooClose(unsigned Reg, unsigned Dist,
- MachineInstr *MI,
- MachineBasicBlock *MBB) {
+ MachineInstr *MI) {
for (MachineRegisterInfo::def_iterator DI = MRI->def_begin(Reg),
DE = MRI->def_end(); DI != DE; ++DI) {
MachineInstr *DefMI = &*DI;
return false;
}
-/// RescheduleKillAboveMI - If there is one more local instruction that reads
+/// rescheduleKillAboveMI - If there is one more local instruction that reads
/// 'Reg' and it kills 'Reg, consider moving the kill instruction above the
/// current two-address instruction in order to eliminate the need for the
/// copy.
-bool
-TwoAddressInstructionPass::RescheduleKillAboveMI(MachineBasicBlock *MBB,
- MachineBasicBlock::iterator &mi,
- MachineBasicBlock::iterator &nmi,
- unsigned Reg) {
+bool TwoAddressInstructionPass::
+rescheduleKillAboveMI(MachineBasicBlock::iterator &mi,
+ MachineBasicBlock::iterator &nmi,
+ unsigned Reg) {
// Bail immediately if we don't have LV available. We use it to find kills
// efficiently.
if (!LV)
if (MO.isUse()) {
if (!MOReg)
continue;
- if (isDefTooClose(MOReg, DI->second, MI, MBB))
+ if (isDefTooClose(MOReg, DI->second, MI))
return false;
if (MOReg == Reg && !MO.isKill())
return false;
return true;
}
-/// TryInstructionTransform - For the case where an instruction has a single
+/// tryInstructionTransform - For the case where an instruction has a single
/// pair of tied register operands, attempt some transformations that may
/// either eliminate the tied operands or improve the opportunities for
/// coalescing away the register copy. Returns true if no copy needs to be
/// inserted to untie mi's operands (either because they were untied, or
/// because mi was rescheduled, and will be visited again later).
bool TwoAddressInstructionPass::
-TryInstructionTransform(MachineBasicBlock::iterator &mi,
+tryInstructionTransform(MachineBasicBlock::iterator &mi,
MachineBasicBlock::iterator &nmi,
- MachineFunction::iterator &mbbi,
- unsigned SrcIdx, unsigned DstIdx, unsigned Dist,
- SmallPtrSet<MachineInstr*, 8> &Processed) {
+ unsigned SrcIdx, unsigned DstIdx, unsigned Dist) {
if (OptLevel == CodeGenOpt::None)
return false;
bool regBKilled = isKilled(MI, regB, MRI, TII);
if (TargetRegisterInfo::isVirtualRegister(regA))
- ScanUses(regA, &*mbbi, Processed);
+ scanUses(regA);
// Check if it is profitable to commute the operands.
unsigned SrcOp1, SrcOp2;
// If C dies but B does not, swap the B and C operands.
// This makes the live ranges of A and C joinable.
TryCommute = true;
- else if (isProfitableToCommute(regA, regB, regC, &MI, mbbi, Dist)) {
+ else if (isProfitableToCommute(regA, regB, regC, &MI, Dist)) {
TryCommute = true;
AggressiveCommute = true;
}
}
// If it's profitable to commute, try to do so.
- if (TryCommute && CommuteInstruction(mi, mbbi, regB, regC, Dist)) {
+ if (TryCommute && commuteInstruction(mi, regB, regC, Dist)) {
++NumCommuted;
if (AggressiveCommute)
++NumAggrCommuted;
// If there is one more use of regB later in the same MBB, consider
// re-schedule this MI below it.
- if (RescheduleMIBelowKill(mbbi, mi, nmi, regB)) {
+ if (rescheduleMIBelowKill(mi, nmi, regB)) {
++NumReSchedDowns;
return true;
}
// three-address instruction. Check if it is profitable.
if (!regBKilled || isProfitableToConv3Addr(regA, regB)) {
// Try to convert it.
- if (ConvertInstTo3Addr(mi, nmi, mbbi, regA, regB, Dist)) {
+ if (convertInstTo3Addr(mi, nmi, regA, regB, Dist)) {
++NumConvertedTo3Addr;
return true; // Done with this instruction.
}
// If there is one more use of regB later in the same MBB, consider
// re-schedule it before this MI if it's legal.
- if (RescheduleKillAboveMI(mbbi, mi, nmi, regB)) {
+ if (rescheduleKillAboveMI(mi, nmi, regB)) {
++NumReSchedUps;
return true;
}
// Tentatively insert the instructions into the block so that they
// look "normal" to the transformation logic.
- mbbi->insert(mi, NewMIs[0]);
- mbbi->insert(mi, NewMIs[1]);
+ MBB->insert(mi, NewMIs[0]);
+ MBB->insert(mi, NewMIs[1]);
DEBUG(dbgs() << "2addr: NEW LOAD: " << *NewMIs[0]
<< "2addr: NEW INST: " << *NewMIs[1]);
unsigned NewSrcIdx = NewMIs[1]->findRegisterUseOperandIdx(regB);
MachineBasicBlock::iterator NewMI = NewMIs[1];
bool TransformSuccess =
- TryInstructionTransform(NewMI, mi, mbbi,
- NewSrcIdx, NewDstIdx, Dist, Processed);
+ tryInstructionTransform(NewMI, mi, NewSrcIdx, NewDstIdx, Dist);
if (TransformSuccess ||
NewMIs[1]->getOperand(NewSrcIdx).isKill()) {
// Success, or at least we made an improvement. Keep the unfolded
MRI->leaveSSA();
TiedOperandMap TiedOperands;
-
- SmallPtrSet<MachineInstr*, 8> Processed;
- for (MachineFunction::iterator mbbi = MF->begin(), mbbe = MF->end();
- mbbi != mbbe; ++mbbi) {
+ for (MachineFunction::iterator MBBI = MF->begin(), MBBE = MF->end();
+ MBBI != MBBE; ++MBBI) {
+ MBB = MBBI;
unsigned Dist = 0;
DistanceMap.clear();
SrcRegMap.clear();
DstRegMap.clear();
Processed.clear();
- for (MachineBasicBlock::iterator mi = mbbi->begin(), me = mbbi->end();
+ for (MachineBasicBlock::iterator mi = MBB->begin(), me = MBB->end();
mi != me; ) {
MachineBasicBlock::iterator nmi = llvm::next(mi);
if (mi->isDebugValue()) {
DistanceMap.insert(std::make_pair(mi, ++Dist));
- ProcessCopy(&*mi, &*mbbi, Processed);
+ processCopy(&*mi);
// First scan through all the tied register uses in this instruction
// and record a list of pairs of tied operands for each register.
unsigned SrcReg = mi->getOperand(SrcIdx).getReg();
unsigned DstReg = mi->getOperand(DstIdx).getReg();
if (SrcReg != DstReg &&
- TryInstructionTransform(mi, nmi, mbbi, SrcIdx, DstIdx, Dist,
- Processed)) {
+ tryInstructionTransform(mi, nmi, SrcIdx, DstIdx, Dist)) {
// The tied operands have been eliminated or shifted further down the
// block to ease elimination. Continue processing with 'nmi'.
TiedOperands.clear();
// Eliminate REG_SEQUENCE instructions. Their whole purpose was to preseve
// SSA form. It's now safe to de-SSA.
- MadeChange |= EliminateRegSequences();
+ MadeChange |= eliminateRegSequences();
return MadeChange;
}
return First;
}
-/// CoalesceExtSubRegs - If a number of sources of the REG_SEQUENCE are
-/// EXTRACT_SUBREG from the same register and to the same virtual register
-/// with different sub-register indices, attempt to combine the
-/// EXTRACT_SUBREGs and pre-coalesce them. e.g.
-/// %reg1026<def> = VLDMQ %reg1025<kill>, 260, pred:14, pred:%reg0
-/// %reg1029:6<def> = EXTRACT_SUBREG %reg1026, 6
-/// %reg1029:5<def> = EXTRACT_SUBREG %reg1026<kill>, 5
-/// Since D subregs 5, 6 can combine to a Q register, we can coalesce
-/// reg1026 to reg1029.
-void
-TwoAddressInstructionPass::CoalesceExtSubRegs(SmallVector<unsigned,4> &Srcs,
- unsigned DstReg) {
- SmallSet<unsigned, 4> Seen;
- for (unsigned i = 0, e = Srcs.size(); i != e; ++i) {
- unsigned SrcReg = Srcs[i];
- if (!Seen.insert(SrcReg))
- continue;
-
- // Check that the instructions are all in the same basic block.
- MachineInstr *SrcDefMI = MRI->getUniqueVRegDef(SrcReg);
- MachineInstr *DstDefMI = MRI->getUniqueVRegDef(DstReg);
- if (!SrcDefMI || !DstDefMI ||
- SrcDefMI->getParent() != DstDefMI->getParent())
- continue;
-
- // If there are no other uses than copies which feed into
- // the reg_sequence, then we might be able to coalesce them.
- bool CanCoalesce = true;
- SmallVector<unsigned, 4> SrcSubIndices, DstSubIndices;
- for (MachineRegisterInfo::use_nodbg_iterator
- UI = MRI->use_nodbg_begin(SrcReg),
- UE = MRI->use_nodbg_end(); UI != UE; ++UI) {
- MachineInstr *UseMI = &*UI;
- if (!UseMI->isCopy() || UseMI->getOperand(0).getReg() != DstReg) {
- CanCoalesce = false;
- break;
- }
- SrcSubIndices.push_back(UseMI->getOperand(1).getSubReg());
- DstSubIndices.push_back(UseMI->getOperand(0).getSubReg());
- }
-
- if (!CanCoalesce || SrcSubIndices.size() < 2)
- continue;
-
- // Check that the source subregisters can be combined.
- std::sort(SrcSubIndices.begin(), SrcSubIndices.end());
- unsigned NewSrcSubIdx = 0;
- if (!TRI->canCombineSubRegIndices(MRI->getRegClass(SrcReg), SrcSubIndices,
- NewSrcSubIdx))
- continue;
-
- // Check that the destination subregisters can also be combined.
- std::sort(DstSubIndices.begin(), DstSubIndices.end());
- unsigned NewDstSubIdx = 0;
- if (!TRI->canCombineSubRegIndices(MRI->getRegClass(DstReg), DstSubIndices,
- NewDstSubIdx))
- continue;
-
- // If neither source nor destination can be combined to the full register,
- // just give up. This could be improved if it ever matters.
- if (NewSrcSubIdx != 0 && NewDstSubIdx != 0)
- continue;
-
- // Now that we know that all the uses are extract_subregs and that those
- // subregs can somehow be combined, scan all the extract_subregs again to
- // make sure the subregs are in the right order and can be composed.
- MachineInstr *SomeMI = 0;
- CanCoalesce = true;
- for (MachineRegisterInfo::use_nodbg_iterator
- UI = MRI->use_nodbg_begin(SrcReg),
- UE = MRI->use_nodbg_end(); UI != UE; ++UI) {
- MachineInstr *UseMI = &*UI;
- assert(UseMI->isCopy());
- unsigned DstSubIdx = UseMI->getOperand(0).getSubReg();
- unsigned SrcSubIdx = UseMI->getOperand(1).getSubReg();
- assert(DstSubIdx != 0 && "missing subreg from RegSequence elimination");
- if ((NewDstSubIdx == 0 &&
- TRI->composeSubRegIndices(NewSrcSubIdx, DstSubIdx) != SrcSubIdx) ||
- (NewSrcSubIdx == 0 &&
- TRI->composeSubRegIndices(NewDstSubIdx, SrcSubIdx) != DstSubIdx)) {
- CanCoalesce = false;
- break;
- }
- // Keep track of one of the uses. Preferably the first one which has a
- // <def,undef> flag.
- if (!SomeMI || UseMI->getOperand(0).isUndef())
- SomeMI = UseMI;
- }
- if (!CanCoalesce)
- continue;
-
- // Insert a copy to replace the original.
- MachineInstr *CopyMI = BuildMI(*SomeMI->getParent(), SomeMI,
- SomeMI->getDebugLoc(),
- TII->get(TargetOpcode::COPY))
- .addReg(DstReg, RegState::Define |
- getUndefRegState(SomeMI->getOperand(0).isUndef()),
- NewDstSubIdx)
- .addReg(SrcReg, 0, NewSrcSubIdx);
-
- // Remove all the old extract instructions.
- for (MachineRegisterInfo::use_nodbg_iterator
- UI = MRI->use_nodbg_begin(SrcReg),
- UE = MRI->use_nodbg_end(); UI != UE; ) {
- MachineInstr *UseMI = &*UI;
- ++UI;
- if (UseMI == CopyMI)
- continue;
- assert(UseMI->isCopy());
- // Move any kills to the new copy or extract instruction.
- if (UseMI->getOperand(1).isKill()) {
- CopyMI->getOperand(1).setIsKill();
- if (LV)
- // Update live variables
- LV->replaceKillInstruction(SrcReg, UseMI, &*CopyMI);
- }
- UseMI->eraseFromParent();
- }
- }
-}
-
static bool HasOtherRegSequenceUses(unsigned Reg, MachineInstr *RegSeq,
MachineRegisterInfo *MRI) {
for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(Reg),
return false;
}
-/// EliminateRegSequences - Eliminate REG_SEQUENCE instructions as part
+/// eliminateRegSequences - Eliminate REG_SEQUENCE instructions as part
/// of the de-ssa process. This replaces sources of REG_SEQUENCE as
/// sub-register references of the register defined by REG_SEQUENCE. e.g.
///
/// %reg1031<def> = REG_SEQUENCE %reg1029<kill>, 5, %reg1030<kill>, 6
/// =>
/// %reg1031:5<def>, %reg1031:6<def> = VLD1q16 %reg1024<kill>, ...
-bool TwoAddressInstructionPass::EliminateRegSequences() {
+bool TwoAddressInstructionPass::eliminateRegSequences() {
if (RegSequences.empty())
return false;
DEBUG(dbgs() << "Eliminated: " << *MI);
MI->eraseFromParent();
}
-
- // Try coalescing some EXTRACT_SUBREG instructions. This can create
- // INSERT_SUBREG instructions that must have <undef> flags added by
- // LiveIntervalAnalysis, so only run it when LiveVariables is available.
- if (LV)
- CoalesceExtSubRegs(RealSrcs, DstReg);
}
RegSequences.clear();
projects / oota-llvm.git / blobdiff