MachineSSAUpdater.cpp Source File (original) (raw)

31#include

33using namespace llvm;

35#define DEBUG_TYPE "machine-ssaupdater"

45 : InsertedPHIs(NewPHI), TII(MF.getSubtarget().getInstrInfo()),

46 MRI(&MF.getRegInfo()) {}

55 if (!AV)

57 else

60 RegAttrs = MRI->getVRegAttrs(V);

61}

78 return GetValueAtEndOfBlockInternal(BB);

79}

81static

83 SmallVectorImpl<std::pair<MachineBasicBlock *, Register>> &PredValues) {

88 if (->isPHI())

92 for (const auto &[SrcBB, SrcReg] : PredValues)

93 AVals[SrcBB] = SrcReg;

94 while (I != BB->end() && I->isPHI()) {

95 bool Same = true;

96 for (unsigned i = 1, e = I->getNumOperands(); i != e; i += 2) {

97 Register SrcReg = I->getOperand(i).getReg();

99 if (AVals[SrcBB] != SrcReg) {

100 Same = false;

101 break;

102 }

103 }

104 if (Same)

105 return I->getOperand(0).getReg();

106 ++I;

107 }

109}

110

111

112

113

119 Register NewVR = MRI->createVirtualRegister(RegAttrs);

121}

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144 bool ExistingValueOnly) {

145

146

148 return GetValueAtEndOfBlockInternal(BB, ExistingValueOnly);

149

150

152

153 if (ExistingValueOnly)

155

158 RegAttrs, MRI, TII);

160 }

161

162

163

166

167 bool isFirstPred = true;

169 Register PredVal = GetValueAtEndOfBlockInternal(PredBB, ExistingValueOnly);

170 PredValues.push_back(std::make_pair(PredBB, PredVal));

171

172

173 if (isFirstPred) {

174 SingularValue = PredVal;

175 isFirstPred = false;

176 } else if (PredVal != SingularValue)

178 }

179

180

181 if (SingularValue)

182 return SingularValue;

183

184

186 if (DupPHI)

187 return DupPHI;

188

189

190 if (ExistingValueOnly)

192

193

196 InsertNewDef(TargetOpcode::PHI, BB, Loc, RegAttrs, MRI, TII);

197

198

199 for (const auto &[SrcBB, SrcReg] : PredValues)

201

202

203

206 return ConstVal;

207 }

208

209

210 if (InsertedPHIs) InsertedPHIs->push_back(InsertedPHI);

211

212 LLVM_DEBUG(dbgs() << " Inserted PHI: " << *InsertedPHI);

213 return InsertedPHI.getReg(0);

214}

215

216static

219 for (unsigned i = 1, e = MI->getNumOperands(); i != e; i += 2) {

220 if (&MI->getOperand(i) == U)

221 return MI->getOperand(i+1).getMBB();

222 }

223

225}

226

227

228

232 if (UseMI->isPHI()) {

234 NewVR = GetValueAtEndOfBlockInternal(SourceBB);

235 } else {

237 }

238

239

240

241

242 if (NewVR) {

245 if (UseRC && !MRI->constrainRegClass(NewVR, UseRC)) {

249 RegAttrs, MRI, TII)

252 LLVM_DEBUG(dbgs() << " Inserted COPY: " << *InsertedCopy);

253 }

254 }

255 U.setReg(NewVR);

256}

257

258namespace llvm {

259

260

261

262template<>

264public:

269

272

273

275 private:

277 unsigned idx;

278

279 public:

283 : PHI(P), idx(PHI->getNumOperands()) {}

284

288

290

292 return PHI->getOperand(idx+1).getMBB();

293 }

294 };

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316 Updater->RegAttrs, Updater->MRI, Updater->TII);

318 }

319

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321

326 InsertNewDef(TargetOpcode::PHI, BB, Loc, Updater->RegAttrs,

327 Updater->MRI, Updater->TII);

328 return PHI->getOperand(0).getReg();

329 }

330

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337

338

340 if (I && I->isPHI())

341 return I;

342 return nullptr;

343 }

344

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355 if (PHI && PHI->getNumOperands() <= 1)

356 return PHI;

357 return nullptr;

358 }

359

360

361

363 return PHI->getOperand(0).getReg();

364 }

365};

366

367}

368

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372

374MachineSSAUpdater::GetValueAtEndOfBlockInternal(MachineBasicBlock *BB,

375 bool ExistingValueOnly) {

378 if (ExistingVal || ExistingValueOnly)

379 return ExistingVal;

380

381 SSAUpdaterImpl Impl(this, &AvailableVals, InsertedPHIs);

382 return Impl.GetValue(BB);

383}

unsigned const MachineRegisterInfo * MRI

MachineInstrBuilder & UseMI

const TargetInstrInfo & TII

This file defines the DenseMap class.

static MachineInstrBuilder InsertNewDef(unsigned Opcode, MachineBasicBlock *BB, MachineBasicBlock::iterator I, MachineRegisterInfo::VRegAttrs RegAttrs, MachineRegisterInfo *MRI, const TargetInstrInfo *TII)

InsertNewDef - Insert an empty PHI or IMPLICIT_DEF instruction which define a value of the given regi...

Definition MachineSSAUpdater.cpp:114

static MachineBasicBlock * findCorrespondingPred(const MachineInstr *MI, MachineOperand *U)

Definition MachineSSAUpdater.cpp:217

static Register LookForIdenticalPHI(MachineBasicBlock *BB, SmallVectorImpl< std::pair< MachineBasicBlock *, Register > > &PredValues)

Definition MachineSSAUpdater.cpp:82

static AvailableValsTy & getAvailableVals(void *AV)

Definition MachineSSAUpdater.cpp:39

DenseMap< MachineBasicBlock *, Register > AvailableValsTy

Definition MachineSSAUpdater.cpp:37

Promote Memory to Register

This file defines the SmallVector class.

ValueT lookup(const_arg_type_t< KeyT > Val) const

lookup - Return the entry for the specified key, or a default constructed value if no such entry exis...

size_type count(const_arg_type_t< KeyT > Val) const

Return 1 if the specified key is in the map, 0 otherwise.

succ_iterator succ_begin()

LLVM_ABI iterator getFirstTerminator()

Returns an iterator to the first terminator instruction of this basic block.

SmallVectorImpl< MachineBasicBlock * >::iterator succ_iterator

LLVM_ABI iterator getFirstNonPHI()

Returns a pointer to the first instruction in this block that is not a PHINode instruction.

iterator_range< pred_iterator > predecessors()

MachineInstrBundleIterator< MachineInstr > iterator

Get the register for the operand index.

const MachineInstrBuilder & addReg(Register RegNo, unsigned flags=0, unsigned SubReg=0) const

Add a new virtual register operand.

const MachineInstrBuilder & addMBB(MachineBasicBlock *MBB, unsigned TargetFlags=0) const

Representation of each machine instruction.

LLVM_ABI Register isConstantValuePHI() const

If the specified instruction is a PHI that always merges together the same virtual register,...

LLVM_ABI void eraseFromParent()

Unlink 'this' from the containing basic block and delete it.

const MachineOperand & getOperand(unsigned i) const

MachineOperand class - Representation of each machine instruction operand.

getReg - Returns the register number.

MachineRegisterInfo - Keep track of information for virtual and physical registers,...

LLVM_ABI MachineInstr * getVRegDef(Register Reg) const

getVRegDef - Return the machine instr that defines the specified virtual register or null if none is ...

MachineSSAUpdater - This class updates SSA form for a set of virtual registers defined in multiple bl...

void Initialize(Register V)

Initialize - Reset this object to get ready for a new set of SSA updates.

Definition MachineSSAUpdater.cpp:54

~MachineSSAUpdater()

Definition MachineSSAUpdater.cpp:48

GetValueInMiddleOfBlock - Construct SSA form, materializing a value that is live in the middle of the...

Definition MachineSSAUpdater.cpp:143

void RewriteUse(MachineOperand &U)

RewriteUse - Rewrite a use of the symbolic value.

Definition MachineSSAUpdater.cpp:229

GetValueAtEndOfBlock - Construct SSA form, materializing a value that is live at the end of the speci...

Definition MachineSSAUpdater.cpp:77

void AddAvailableValue(MachineBasicBlock *BB, Register V)

AddAvailableValue - Indicate that a rewritten value is available at the end of the specified block wi...

Definition MachineSSAUpdater.cpp:71

bool HasValueForBlock(MachineBasicBlock *BB) const

HasValueForBlock - Return true if the MachineSSAUpdater already has a value for the specified block.

Definition MachineSSAUpdater.cpp:65

MachineSSAUpdater(MachineFunction &MF, SmallVectorImpl< MachineInstr * > *NewPHI=nullptr)

MachineSSAUpdater constructor.

Definition MachineSSAUpdater.cpp:43

Wrapper class representing virtual and physical registers.

Iterator for PHI operands.

Definition MachineSSAUpdater.cpp:274

bool operator!=(const PHI_iterator &x) const

Definition MachineSSAUpdater.cpp:287

bool operator==(const PHI_iterator &x) const

Definition MachineSSAUpdater.cpp:286

PHI_iterator & operator++()

Definition MachineSSAUpdater.cpp:285

Definition MachineSSAUpdater.cpp:289

PHI_iterator(MachineInstr *P, bool)

Definition MachineSSAUpdater.cpp:282

MachineBasicBlock * getIncomingBlock()

Definition MachineSSAUpdater.cpp:291

PHI_iterator(MachineInstr *P)

Definition MachineSSAUpdater.cpp:280

static MachineInstr * ValueIsNewPHI(Register Val, MachineSSAUpdater *Updater)

ValueIsNewPHI - Like ValueIsPHI but also check if the PHI has no source operands, i....

Definition MachineSSAUpdater.cpp:353

static Register CreateEmptyPHI(MachineBasicBlock *BB, unsigned NumPreds, MachineSSAUpdater *Updater)

CreateEmptyPHI - Create a PHI instruction that defines a new register.

Definition MachineSSAUpdater.cpp:322

static PHI_iterator PHI_begin(PhiT *PHI)

Definition MachineSSAUpdater.cpp:296

static Register GetPHIValue(MachineInstr *PHI)

GetPHIValue - For the specified PHI instruction, return the register that it defines.

Definition MachineSSAUpdater.cpp:362

MachineInstr PhiT

Definition MachineSSAUpdater.cpp:267

static void FindPredecessorBlocks(MachineBasicBlock *BB, SmallVectorImpl< MachineBasicBlock * > *Preds)

FindPredecessorBlocks - Put the predecessors of BB into the Preds vector.

Definition MachineSSAUpdater.cpp:304

MachineBasicBlock::succ_iterator BlkSucc_iterator

Definition MachineSSAUpdater.cpp:268

static MachineInstr * ValueIsPHI(Register Val, MachineSSAUpdater *Updater)

ValueIsPHI - Check if the instruction that defines the specified register is a PHI instruction.

Definition MachineSSAUpdater.cpp:347

static Register GetPoisonVal(MachineBasicBlock *BB, MachineSSAUpdater *Updater)

GetPoisonVal - Create an IMPLICIT_DEF instruction with a new register.

Definition MachineSSAUpdater.cpp:311

static MachineInstr * InstrIsPHI(MachineInstr *I)

InstrIsPHI - Check if an instruction is a PHI.

Definition MachineSSAUpdater.cpp:339

static BlkSucc_iterator BlkSucc_begin(BlkT *BB)

Definition MachineSSAUpdater.cpp:270

static BlkSucc_iterator BlkSucc_end(BlkT *BB)

Definition MachineSSAUpdater.cpp:271

static void AddPHIOperand(MachineInstr *PHI, Register Val, MachineBasicBlock *Pred)

AddPHIOperand - Add the specified value as an operand of the PHI for the specified predecessor block.

Definition MachineSSAUpdater.cpp:333

MachineBasicBlock BlkT

Definition MachineSSAUpdater.cpp:265

static PHI_iterator PHI_end(PhiT *PHI)

Definition MachineSSAUpdater.cpp:298

Definition MachineSSAUpdater.cpp:266

This class consists of common code factored out of the SmallVector class to reduce code duplication b...

void push_back(const T &Elt)

This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.

TargetInstrInfo - Interface to description of machine instruction set.

#define llvm_unreachable(msg)

Marks that the current location is not supposed to be reachable.

This is an optimization pass for GlobalISel generic memory operations.

MachineInstrBuilder BuildMI(MachineFunction &MF, const MIMetadata &MIMD, const MCInstrDesc &MCID)

Builder interface. Specify how to create the initial instruction itself.

void append_range(Container &C, Range &&R)

Wrapper function to append range R to container C.

bool operator==(const AddressRangeValuePair &LHS, const AddressRangeValuePair &RHS)

auto dyn_cast_or_null(const Y &Val)

LLVM_ABI raw_ostream & dbgs()

dbgs() - This returns a reference to a raw_ostream for debugging messages.

All attributes(register class or bank and low-level type) a virtual register can have.