LLVM  14.0.0git
X86FixupLEAs.cpp
Go to the documentation of this file.
1 //===-- X86FixupLEAs.cpp - use or replace LEA instructions -----------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the pass that finds instructions that can be
10 // re-written as LEA instructions in order to reduce pipeline delays.
11 // It replaces LEAs with ADD/INC/DEC when that is better for size/speed.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "X86.h"
16 #include "X86InstrInfo.h"
17 #include "X86Subtarget.h"
18 #include "llvm/ADT/Statistic.h"
24 #include "llvm/CodeGen/Passes.h"
26 #include "llvm/Support/Debug.h"
28 using namespace llvm;
29 
30 #define FIXUPLEA_DESC "X86 LEA Fixup"
31 #define FIXUPLEA_NAME "x86-fixup-LEAs"
32 
33 #define DEBUG_TYPE FIXUPLEA_NAME
34 
35 STATISTIC(NumLEAs, "Number of LEA instructions created");
36 
37 namespace {
38 class FixupLEAPass : public MachineFunctionPass {
39  enum RegUsageState { RU_NotUsed, RU_Write, RU_Read };
40 
41  /// Given a machine register, look for the instruction
42  /// which writes it in the current basic block. If found,
43  /// try to replace it with an equivalent LEA instruction.
44  /// If replacement succeeds, then also process the newly created
45  /// instruction.
46  void seekLEAFixup(MachineOperand &p, MachineBasicBlock::iterator &I,
48 
49  /// Given a memory access or LEA instruction
50  /// whose address mode uses a base and/or index register, look for
51  /// an opportunity to replace the instruction which sets the base or index
52  /// register with an equivalent LEA instruction.
53  void processInstruction(MachineBasicBlock::iterator &I,
55 
56  /// Given a LEA instruction which is unprofitable
57  /// on SlowLEA targets try to replace it with an equivalent ADD instruction.
58  void processInstructionForSlowLEA(MachineBasicBlock::iterator &I,
60 
61  /// Given a LEA instruction which is unprofitable
62  /// on SNB+ try to replace it with other instructions.
63  /// According to Intel's Optimization Reference Manual:
64  /// " For LEA instructions with three source operands and some specific
65  /// situations, instruction latency has increased to 3 cycles, and must
66  /// dispatch via port 1:
67  /// - LEA that has all three source operands: base, index, and offset
68  /// - LEA that uses base and index registers where the base is EBP, RBP,
69  /// or R13
70  /// - LEA that uses RIP relative addressing mode
71  /// - LEA that uses 16-bit addressing mode "
72  /// This function currently handles the first 2 cases only.
73  void processInstrForSlow3OpLEA(MachineBasicBlock::iterator &I,
74  MachineBasicBlock &MBB, bool OptIncDec);
75 
76  /// Look for LEAs that are really two address LEAs that we might be able to
77  /// turn into regular ADD instructions.
78  bool optTwoAddrLEA(MachineBasicBlock::iterator &I,
79  MachineBasicBlock &MBB, bool OptIncDec,
80  bool UseLEAForSP) const;
81 
82  /// Look for and transform the sequence
83  /// lea (reg1, reg2), reg3
84  /// sub reg3, reg4
85  /// to
86  /// sub reg1, reg4
87  /// sub reg2, reg4
88  /// It can also optimize the sequence lea/add similarly.
89  bool optLEAALU(MachineBasicBlock::iterator &I, MachineBasicBlock &MBB) const;
90 
91  /// Step forwards in MBB, looking for an ADD/SUB instruction which uses
92  /// the dest register of LEA instruction I.
94  MachineBasicBlock &MBB) const;
95 
96  /// Check instructions between LeaI and AluI (exclusively).
97  /// Set BaseIndexDef to true if base or index register from LeaI is defined.
98  /// Set AluDestRef to true if the dest register of AluI is used or defined.
99  /// *KilledBase is set to the killed base register usage.
100  /// *KilledIndex is set to the killed index register usage.
101  void checkRegUsage(MachineBasicBlock::iterator &LeaI,
102  MachineBasicBlock::iterator &AluI, bool &BaseIndexDef,
103  bool &AluDestRef, MachineOperand **KilledBase,
104  MachineOperand **KilledIndex) const;
105 
106  /// Determine if an instruction references a machine register
107  /// and, if so, whether it reads or writes the register.
108  RegUsageState usesRegister(MachineOperand &p, MachineBasicBlock::iterator I);
109 
110  /// Step backwards through a basic block, looking
111  /// for an instruction which writes a register within
112  /// a maximum of INSTR_DISTANCE_THRESHOLD instruction latency cycles.
116 
117  /// if an instruction can be converted to an
118  /// equivalent LEA, insert the new instruction into the basic block
119  /// and return a pointer to it. Otherwise, return zero.
120  MachineInstr *postRAConvertToLEA(MachineBasicBlock &MBB,
122 
123 public:
124  static char ID;
125 
126  StringRef getPassName() const override { return FIXUPLEA_DESC; }
127 
128  FixupLEAPass() : MachineFunctionPass(ID) { }
129 
130  /// Loop over all of the basic blocks,
131  /// replacing instructions by equivalent LEA instructions
132  /// if needed and when possible.
133  bool runOnMachineFunction(MachineFunction &MF) override;
134 
135  // This pass runs after regalloc and doesn't support VReg operands.
136  MachineFunctionProperties getRequiredProperties() const override {
139  }
140 
141  void getAnalysisUsage(AnalysisUsage &AU) const override {
145  }
146 
147 private:
148  TargetSchedModel TSM;
149  const X86InstrInfo *TII = nullptr;
150  const X86RegisterInfo *TRI = nullptr;
151 };
152 }
153 
154 char FixupLEAPass::ID = 0;
155 
156 INITIALIZE_PASS(FixupLEAPass, FIXUPLEA_NAME, FIXUPLEA_DESC, false, false)
157 
158 MachineInstr *
159 FixupLEAPass::postRAConvertToLEA(MachineBasicBlock &MBB,
160  MachineBasicBlock::iterator &MBBI) const {
161  MachineInstr &MI = *MBBI;
162  switch (MI.getOpcode()) {
163  case X86::MOV32rr:
164  case X86::MOV64rr: {
165  const MachineOperand &Src = MI.getOperand(1);
166  const MachineOperand &Dest = MI.getOperand(0);
167  MachineInstr *NewMI =
168  BuildMI(MBB, MBBI, MI.getDebugLoc(),
169  TII->get(MI.getOpcode() == X86::MOV32rr ? X86::LEA32r
170  : X86::LEA64r))
171  .add(Dest)
172  .add(Src)
173  .addImm(1)
174  .addReg(0)
175  .addImm(0)
176  .addReg(0);
177  return NewMI;
178  }
179  }
180 
181  if (!MI.isConvertibleTo3Addr())
182  return nullptr;
183 
184  switch (MI.getOpcode()) {
185  default:
186  // Only convert instructions that we've verified are safe.
187  return nullptr;
188  case X86::ADD64ri32:
189  case X86::ADD64ri8:
190  case X86::ADD64ri32_DB:
191  case X86::ADD64ri8_DB:
192  case X86::ADD32ri:
193  case X86::ADD32ri8:
194  case X86::ADD32ri_DB:
195  case X86::ADD32ri8_DB:
196  if (!MI.getOperand(2).isImm()) {
197  // convertToThreeAddress will call getImm()
198  // which requires isImm() to be true
199  return nullptr;
200  }
201  break;
202  case X86::SHL64ri:
203  case X86::SHL32ri:
204  case X86::INC64r:
205  case X86::INC32r:
206  case X86::DEC64r:
207  case X86::DEC32r:
208  case X86::ADD64rr:
209  case X86::ADD64rr_DB:
210  case X86::ADD32rr:
211  case X86::ADD32rr_DB:
212  // These instructions are all fine to convert.
213  break;
214  }
215  return TII->convertToThreeAddress(MI, nullptr, nullptr);
216 }
217 
218 FunctionPass *llvm::createX86FixupLEAs() { return new FixupLEAPass(); }
219 
220 static bool isLEA(unsigned Opcode) {
221  return Opcode == X86::LEA32r || Opcode == X86::LEA64r ||
222  Opcode == X86::LEA64_32r;
223 }
224 
225 bool FixupLEAPass::runOnMachineFunction(MachineFunction &MF) {
226  if (skipFunction(MF.getFunction()))
227  return false;
228 
229  const X86Subtarget &ST = MF.getSubtarget<X86Subtarget>();
230  bool IsSlowLEA = ST.slowLEA();
231  bool IsSlow3OpsLEA = ST.slow3OpsLEA();
232  bool LEAUsesAG = ST.LEAusesAG();
233 
234  bool OptIncDec = !ST.slowIncDec() || MF.getFunction().hasOptSize();
235  bool UseLEAForSP = ST.useLeaForSP();
236 
237  TSM.init(&ST);
238  TII = ST.getInstrInfo();
239  TRI = ST.getRegisterInfo();
240  auto *PSI = &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
241  auto *MBFI = (PSI && PSI->hasProfileSummary())
242  ? &getAnalysis<LazyMachineBlockFrequencyInfoPass>().getBFI()
243  : nullptr;
244 
245  LLVM_DEBUG(dbgs() << "Start X86FixupLEAs\n";);
246  for (MachineBasicBlock &MBB : MF) {
247  // First pass. Try to remove or optimize existing LEAs.
248  bool OptIncDecPerBB =
249  OptIncDec || llvm::shouldOptimizeForSize(&MBB, PSI, MBFI);
250  for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ++I) {
251  if (!isLEA(I->getOpcode()))
252  continue;
253 
254  if (optTwoAddrLEA(I, MBB, OptIncDecPerBB, UseLEAForSP))
255  continue;
256 
257  if (IsSlowLEA)
258  processInstructionForSlowLEA(I, MBB);
259  else if (IsSlow3OpsLEA)
260  processInstrForSlow3OpLEA(I, MBB, OptIncDecPerBB);
261  }
262 
263  // Second pass for creating LEAs. This may reverse some of the
264  // transformations above.
265  if (LEAUsesAG) {
266  for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ++I)
267  processInstruction(I, MBB);
268  }
269  }
270 
271  LLVM_DEBUG(dbgs() << "End X86FixupLEAs\n";);
272 
273  return true;
274 }
275 
276 FixupLEAPass::RegUsageState
277 FixupLEAPass::usesRegister(MachineOperand &p, MachineBasicBlock::iterator I) {
278  RegUsageState RegUsage = RU_NotUsed;
279  MachineInstr &MI = *I;
280 
281  for (const MachineOperand &MO : MI.operands()) {
282  if (MO.isReg() && MO.getReg() == p.getReg()) {
283  if (MO.isDef())
284  return RU_Write;
285  RegUsage = RU_Read;
286  }
287  }
288  return RegUsage;
289 }
290 
291 /// getPreviousInstr - Given a reference to an instruction in a basic
292 /// block, return a reference to the previous instruction in the block,
293 /// wrapping around to the last instruction of the block if the block
294 /// branches to itself.
297  if (I == MBB.begin()) {
298  if (MBB.isPredecessor(&MBB)) {
299  I = --MBB.end();
300  return true;
301  } else
302  return false;
303  }
304  --I;
305  return true;
306 }
307 
309 FixupLEAPass::searchBackwards(MachineOperand &p, MachineBasicBlock::iterator &I,
311  int InstrDistance = 1;
313  static const int INSTR_DISTANCE_THRESHOLD = 5;
314 
315  CurInst = I;
316  bool Found;
317  Found = getPreviousInstr(CurInst, MBB);
318  while (Found && I != CurInst) {
319  if (CurInst->isCall() || CurInst->isInlineAsm())
320  break;
321  if (InstrDistance > INSTR_DISTANCE_THRESHOLD)
322  break; // too far back to make a difference
323  if (usesRegister(p, CurInst) == RU_Write) {
324  return CurInst;
325  }
326  InstrDistance += TSM.computeInstrLatency(&*CurInst);
327  Found = getPreviousInstr(CurInst, MBB);
328  }
330 }
331 
332 static inline bool isInefficientLEAReg(unsigned Reg) {
333  return Reg == X86::EBP || Reg == X86::RBP ||
334  Reg == X86::R13D || Reg == X86::R13;
335 }
336 
337 /// Returns true if this LEA uses base an index registers, and the base register
338 /// is known to be inefficient for the subtarget.
339 // TODO: use a variant scheduling class to model the latency profile
340 // of LEA instructions, and implement this logic as a scheduling predicate.
341 static inline bool hasInefficientLEABaseReg(const MachineOperand &Base,
342  const MachineOperand &Index) {
343  return Base.isReg() && isInefficientLEAReg(Base.getReg()) && Index.isReg() &&
344  Index.getReg() != X86::NoRegister;
345 }
346 
347 static inline bool hasLEAOffset(const MachineOperand &Offset) {
348  return (Offset.isImm() && Offset.getImm() != 0) || Offset.isGlobal();
349 }
350 
351 static inline unsigned getADDrrFromLEA(unsigned LEAOpcode) {
352  switch (LEAOpcode) {
353  default:
354  llvm_unreachable("Unexpected LEA instruction");
355  case X86::LEA32r:
356  case X86::LEA64_32r:
357  return X86::ADD32rr;
358  case X86::LEA64r:
359  return X86::ADD64rr;
360  }
361 }
362 
363 static inline unsigned getSUBrrFromLEA(unsigned LEAOpcode) {
364  switch (LEAOpcode) {
365  default:
366  llvm_unreachable("Unexpected LEA instruction");
367  case X86::LEA32r:
368  case X86::LEA64_32r:
369  return X86::SUB32rr;
370  case X86::LEA64r:
371  return X86::SUB64rr;
372  }
373 }
374 
375 static inline unsigned getADDriFromLEA(unsigned LEAOpcode,
376  const MachineOperand &Offset) {
377  bool IsInt8 = Offset.isImm() && isInt<8>(Offset.getImm());
378  switch (LEAOpcode) {
379  default:
380  llvm_unreachable("Unexpected LEA instruction");
381  case X86::LEA32r:
382  case X86::LEA64_32r:
383  return IsInt8 ? X86::ADD32ri8 : X86::ADD32ri;
384  case X86::LEA64r:
385  return IsInt8 ? X86::ADD64ri8 : X86::ADD64ri32;
386  }
387 }
388 
389 static inline unsigned getINCDECFromLEA(unsigned LEAOpcode, bool IsINC) {
390  switch (LEAOpcode) {
391  default:
392  llvm_unreachable("Unexpected LEA instruction");
393  case X86::LEA32r:
394  case X86::LEA64_32r:
395  return IsINC ? X86::INC32r : X86::DEC32r;
396  case X86::LEA64r:
397  return IsINC ? X86::INC64r : X86::DEC64r;
398  }
399 }
400 
402 FixupLEAPass::searchALUInst(MachineBasicBlock::iterator &I,
403  MachineBasicBlock &MBB) const {
404  const int InstrDistanceThreshold = 5;
405  int InstrDistance = 1;
406  MachineBasicBlock::iterator CurInst = std::next(I);
407 
408  unsigned LEAOpcode = I->getOpcode();
409  unsigned AddOpcode = getADDrrFromLEA(LEAOpcode);
410  unsigned SubOpcode = getSUBrrFromLEA(LEAOpcode);
411  Register DestReg = I->getOperand(0).getReg();
412 
413  while (CurInst != MBB.end()) {
414  if (CurInst->isCall() || CurInst->isInlineAsm())
415  break;
416  if (InstrDistance > InstrDistanceThreshold)
417  break;
418 
419  // Check if the lea dest register is used in an add/sub instruction only.
420  for (unsigned I = 0, E = CurInst->getNumOperands(); I != E; ++I) {
421  MachineOperand &Opnd = CurInst->getOperand(I);
422  if (Opnd.isReg()) {
423  if (Opnd.getReg() == DestReg) {
424  if (Opnd.isDef() || !Opnd.isKill())
426 
427  unsigned AluOpcode = CurInst->getOpcode();
428  if (AluOpcode != AddOpcode && AluOpcode != SubOpcode)
430 
431  MachineOperand &Opnd2 = CurInst->getOperand(3 - I);
432  MachineOperand AluDest = CurInst->getOperand(0);
433  if (Opnd2.getReg() != AluDest.getReg())
435 
436  // X - (Y + Z) may generate different flags than (X - Y) - Z when
437  // there is overflow. So we can't change the alu instruction if the
438  // flags register is live.
439  if (!CurInst->registerDefIsDead(X86::EFLAGS, TRI))
441 
442  return CurInst;
443  }
444  if (TRI->regsOverlap(DestReg, Opnd.getReg()))
446  }
447  }
448 
449  InstrDistance++;
450  ++CurInst;
451  }
453 }
454 
455 void FixupLEAPass::checkRegUsage(MachineBasicBlock::iterator &LeaI,
457  bool &BaseIndexDef, bool &AluDestRef,
458  MachineOperand **KilledBase,
459  MachineOperand **KilledIndex) const {
460  BaseIndexDef = AluDestRef = false;
461  *KilledBase = *KilledIndex = nullptr;
462  Register BaseReg = LeaI->getOperand(1 + X86::AddrBaseReg).getReg();
463  Register IndexReg = LeaI->getOperand(1 + X86::AddrIndexReg).getReg();
464  Register AluDestReg = AluI->getOperand(0).getReg();
465 
466  MachineBasicBlock::iterator CurInst = std::next(LeaI);
467  while (CurInst != AluI) {
468  for (unsigned I = 0, E = CurInst->getNumOperands(); I != E; ++I) {
469  MachineOperand &Opnd = CurInst->getOperand(I);
470  if (!Opnd.isReg())
471  continue;
472  Register Reg = Opnd.getReg();
473  if (TRI->regsOverlap(Reg, AluDestReg))
474  AluDestRef = true;
475  if (TRI->regsOverlap(Reg, BaseReg)) {
476  if (Opnd.isDef())
477  BaseIndexDef = true;
478  else if (Opnd.isKill())
479  *KilledBase = &Opnd;
480  }
481  if (TRI->regsOverlap(Reg, IndexReg)) {
482  if (Opnd.isDef())
483  BaseIndexDef = true;
484  else if (Opnd.isKill())
485  *KilledIndex = &Opnd;
486  }
487  }
488  ++CurInst;
489  }
490 }
491 
492 bool FixupLEAPass::optLEAALU(MachineBasicBlock::iterator &I,
493  MachineBasicBlock &MBB) const {
494  // Look for an add/sub instruction which uses the result of lea.
495  MachineBasicBlock::iterator AluI = searchALUInst(I, MBB);
496  if (AluI == MachineBasicBlock::iterator())
497  return false;
498 
499  // Check if there are any related register usage between lea and alu.
500  bool BaseIndexDef, AluDestRef;
501  MachineOperand *KilledBase, *KilledIndex;
502  checkRegUsage(I, AluI, BaseIndexDef, AluDestRef, &KilledBase, &KilledIndex);
503 
504  MachineBasicBlock::iterator InsertPos = AluI;
505  if (BaseIndexDef) {
506  if (AluDestRef)
507  return false;
508  InsertPos = I;
509  KilledBase = KilledIndex = nullptr;
510  }
511 
512  // Check if there are same registers.
513  Register AluDestReg = AluI->getOperand(0).getReg();
514  Register BaseReg = I->getOperand(1 + X86::AddrBaseReg).getReg();
515  Register IndexReg = I->getOperand(1 + X86::AddrIndexReg).getReg();
516  if (I->getOpcode() == X86::LEA64_32r) {
517  BaseReg = TRI->getSubReg(BaseReg, X86::sub_32bit);
518  IndexReg = TRI->getSubReg(IndexReg, X86::sub_32bit);
519  }
520  if (AluDestReg == IndexReg) {
521  if (BaseReg == IndexReg)
522  return false;
523  std::swap(BaseReg, IndexReg);
524  std::swap(KilledBase, KilledIndex);
525  }
526  if (BaseReg == IndexReg)
527  KilledBase = nullptr;
528 
529  // Now it's safe to change instructions.
530  MachineInstr *NewMI1, *NewMI2;
531  unsigned NewOpcode = AluI->getOpcode();
532  NewMI1 = BuildMI(MBB, InsertPos, AluI->getDebugLoc(), TII->get(NewOpcode),
533  AluDestReg)
534  .addReg(AluDestReg, RegState::Kill)
535  .addReg(BaseReg, KilledBase ? RegState::Kill : 0);
536  NewMI1->addRegisterDead(X86::EFLAGS, TRI);
537  NewMI2 = BuildMI(MBB, InsertPos, AluI->getDebugLoc(), TII->get(NewOpcode),
538  AluDestReg)
539  .addReg(AluDestReg, RegState::Kill)
540  .addReg(IndexReg, KilledIndex ? RegState::Kill : 0);
541  NewMI2->addRegisterDead(X86::EFLAGS, TRI);
542 
543  // Clear the old Kill flags.
544  if (KilledBase)
545  KilledBase->setIsKill(false);
546  if (KilledIndex)
547  KilledIndex->setIsKill(false);
548 
549  MBB.getParent()->substituteDebugValuesForInst(*AluI, *NewMI1, 1);
550  MBB.getParent()->substituteDebugValuesForInst(*AluI, *NewMI2, 1);
551  MBB.erase(I);
552  MBB.erase(AluI);
553  I = NewMI1;
554  return true;
555 }
556 
557 bool FixupLEAPass::optTwoAddrLEA(MachineBasicBlock::iterator &I,
558  MachineBasicBlock &MBB, bool OptIncDec,
559  bool UseLEAForSP) const {
560  MachineInstr &MI = *I;
561 
562  const MachineOperand &Base = MI.getOperand(1 + X86::AddrBaseReg);
563  const MachineOperand &Scale = MI.getOperand(1 + X86::AddrScaleAmt);
564  const MachineOperand &Index = MI.getOperand(1 + X86::AddrIndexReg);
565  const MachineOperand &Disp = MI.getOperand(1 + X86::AddrDisp);
566  const MachineOperand &Segment = MI.getOperand(1 + X86::AddrSegmentReg);
567 
568  if (Segment.getReg() != 0 || !Disp.isImm() || Scale.getImm() > 1 ||
569  MBB.computeRegisterLiveness(TRI, X86::EFLAGS, I) !=
571  return false;
572 
573  Register DestReg = MI.getOperand(0).getReg();
574  Register BaseReg = Base.getReg();
575  Register IndexReg = Index.getReg();
576 
577  // Don't change stack adjustment LEAs.
578  if (UseLEAForSP && (DestReg == X86::ESP || DestReg == X86::RSP))
579  return false;
580 
581  // LEA64_32 has 64-bit operands but 32-bit result.
582  if (MI.getOpcode() == X86::LEA64_32r) {
583  if (BaseReg != 0)
584  BaseReg = TRI->getSubReg(BaseReg, X86::sub_32bit);
585  if (IndexReg != 0)
586  IndexReg = TRI->getSubReg(IndexReg, X86::sub_32bit);
587  }
588 
589  MachineInstr *NewMI = nullptr;
590 
591  // Case 1.
592  // Look for lea(%reg1, %reg2), %reg1 or lea(%reg2, %reg1), %reg1
593  // which can be turned into add %reg2, %reg1
594  if (BaseReg != 0 && IndexReg != 0 && Disp.getImm() == 0 &&
595  (DestReg == BaseReg || DestReg == IndexReg)) {
596  unsigned NewOpcode = getADDrrFromLEA(MI.getOpcode());
597  if (DestReg != BaseReg)
598  std::swap(BaseReg, IndexReg);
599 
600  if (MI.getOpcode() == X86::LEA64_32r) {
601  // TODO: Do we need the super register implicit use?
602  NewMI = BuildMI(MBB, I, MI.getDebugLoc(), TII->get(NewOpcode), DestReg)
603  .addReg(BaseReg).addReg(IndexReg)
604  .addReg(Base.getReg(), RegState::Implicit)
605  .addReg(Index.getReg(), RegState::Implicit);
606  } else {
607  NewMI = BuildMI(MBB, I, MI.getDebugLoc(), TII->get(NewOpcode), DestReg)
608  .addReg(BaseReg).addReg(IndexReg);
609  }
610  } else if (DestReg == BaseReg && IndexReg == 0) {
611  // Case 2.
612  // This is an LEA with only a base register and a displacement,
613  // We can use ADDri or INC/DEC.
614 
615  // Does this LEA have one these forms:
616  // lea %reg, 1(%reg)
617  // lea %reg, -1(%reg)
618  if (OptIncDec && (Disp.getImm() == 1 || Disp.getImm() == -1)) {
619  bool IsINC = Disp.getImm() == 1;
620  unsigned NewOpcode = getINCDECFromLEA(MI.getOpcode(), IsINC);
621 
622  if (MI.getOpcode() == X86::LEA64_32r) {
623  // TODO: Do we need the super register implicit use?
624  NewMI = BuildMI(MBB, I, MI.getDebugLoc(), TII->get(NewOpcode), DestReg)
625  .addReg(BaseReg).addReg(Base.getReg(), RegState::Implicit);
626  } else {
627  NewMI = BuildMI(MBB, I, MI.getDebugLoc(), TII->get(NewOpcode), DestReg)
628  .addReg(BaseReg);
629  }
630  } else {
631  unsigned NewOpcode = getADDriFromLEA(MI.getOpcode(), Disp);
632  if (MI.getOpcode() == X86::LEA64_32r) {
633  // TODO: Do we need the super register implicit use?
634  NewMI = BuildMI(MBB, I, MI.getDebugLoc(), TII->get(NewOpcode), DestReg)
635  .addReg(BaseReg).addImm(Disp.getImm())
636  .addReg(Base.getReg(), RegState::Implicit);
637  } else {
638  NewMI = BuildMI(MBB, I, MI.getDebugLoc(), TII->get(NewOpcode), DestReg)
639  .addReg(BaseReg).addImm(Disp.getImm());
640  }
641  }
642  } else if (BaseReg != 0 && IndexReg != 0 && Disp.getImm() == 0) {
643  // Case 3.
644  // Look for and transform the sequence
645  // lea (reg1, reg2), reg3
646  // sub reg3, reg4
647  return optLEAALU(I, MBB);
648  } else
649  return false;
650 
652  MBB.erase(I);
653  I = NewMI;
654  return true;
655 }
656 
657 void FixupLEAPass::processInstruction(MachineBasicBlock::iterator &I,
659  // Process a load, store, or LEA instruction.
660  MachineInstr &MI = *I;
661  const MCInstrDesc &Desc = MI.getDesc();
662  int AddrOffset = X86II::getMemoryOperandNo(Desc.TSFlags);
663  if (AddrOffset >= 0) {
664  AddrOffset += X86II::getOperandBias(Desc);
665  MachineOperand &p = MI.getOperand(AddrOffset + X86::AddrBaseReg);
666  if (p.isReg() && p.getReg() != X86::ESP) {
667  seekLEAFixup(p, I, MBB);
668  }
669  MachineOperand &q = MI.getOperand(AddrOffset + X86::AddrIndexReg);
670  if (q.isReg() && q.getReg() != X86::ESP) {
671  seekLEAFixup(q, I, MBB);
672  }
673  }
674 }
675 
676 void FixupLEAPass::seekLEAFixup(MachineOperand &p,
679  MachineBasicBlock::iterator MBI = searchBackwards(p, I, MBB);
680  if (MBI != MachineBasicBlock::iterator()) {
681  MachineInstr *NewMI = postRAConvertToLEA(MBB, MBI);
682  if (NewMI) {
683  ++NumLEAs;
684  LLVM_DEBUG(dbgs() << "FixLEA: Candidate to replace:"; MBI->dump(););
685  // now to replace with an equivalent LEA...
686  LLVM_DEBUG(dbgs() << "FixLEA: Replaced by: "; NewMI->dump(););
687  MBB.getParent()->substituteDebugValuesForInst(*MBI, *NewMI, 1);
688  MBB.erase(MBI);
690  static_cast<MachineBasicBlock::iterator>(NewMI);
691  processInstruction(J, MBB);
692  }
693  }
694 }
695 
696 void FixupLEAPass::processInstructionForSlowLEA(MachineBasicBlock::iterator &I,
698  MachineInstr &MI = *I;
699  const unsigned Opcode = MI.getOpcode();
700 
701  const MachineOperand &Dst = MI.getOperand(0);
702  const MachineOperand &Base = MI.getOperand(1 + X86::AddrBaseReg);
703  const MachineOperand &Scale = MI.getOperand(1 + X86::AddrScaleAmt);
704  const MachineOperand &Index = MI.getOperand(1 + X86::AddrIndexReg);
705  const MachineOperand &Offset = MI.getOperand(1 + X86::AddrDisp);
706  const MachineOperand &Segment = MI.getOperand(1 + X86::AddrSegmentReg);
707 
708  if (Segment.getReg() != 0 || !Offset.isImm() ||
709  MBB.computeRegisterLiveness(TRI, X86::EFLAGS, I, 4) !=
711  return;
712  const Register DstR = Dst.getReg();
713  const Register SrcR1 = Base.getReg();
714  const Register SrcR2 = Index.getReg();
715  if ((SrcR1 == 0 || SrcR1 != DstR) && (SrcR2 == 0 || SrcR2 != DstR))
716  return;
717  if (Scale.getImm() > 1)
718  return;
719  LLVM_DEBUG(dbgs() << "FixLEA: Candidate to replace:"; I->dump(););
720  LLVM_DEBUG(dbgs() << "FixLEA: Replaced by: ";);
721  MachineInstr *NewMI = nullptr;
722  // Make ADD instruction for two registers writing to LEA's destination
723  if (SrcR1 != 0 && SrcR2 != 0) {
724  const MCInstrDesc &ADDrr = TII->get(getADDrrFromLEA(Opcode));
725  const MachineOperand &Src = SrcR1 == DstR ? Index : Base;
726  NewMI =
727  BuildMI(MBB, I, MI.getDebugLoc(), ADDrr, DstR).addReg(DstR).add(Src);
728  LLVM_DEBUG(NewMI->dump(););
729  }
730  // Make ADD instruction for immediate
731  if (Offset.getImm() != 0) {
732  const MCInstrDesc &ADDri =
733  TII->get(getADDriFromLEA(Opcode, Offset));
734  const MachineOperand &SrcR = SrcR1 == DstR ? Base : Index;
735  NewMI = BuildMI(MBB, I, MI.getDebugLoc(), ADDri, DstR)
736  .add(SrcR)
737  .addImm(Offset.getImm());
738  LLVM_DEBUG(NewMI->dump(););
739  }
740  if (NewMI) {
742  MBB.erase(I);
743  I = NewMI;
744  }
745 }
746 
747 void FixupLEAPass::processInstrForSlow3OpLEA(MachineBasicBlock::iterator &I,
749  bool OptIncDec) {
750  MachineInstr &MI = *I;
751  const unsigned LEAOpcode = MI.getOpcode();
752 
753  const MachineOperand &Dest = MI.getOperand(0);
754  const MachineOperand &Base = MI.getOperand(1 + X86::AddrBaseReg);
755  const MachineOperand &Scale = MI.getOperand(1 + X86::AddrScaleAmt);
756  const MachineOperand &Index = MI.getOperand(1 + X86::AddrIndexReg);
757  const MachineOperand &Offset = MI.getOperand(1 + X86::AddrDisp);
758  const MachineOperand &Segment = MI.getOperand(1 + X86::AddrSegmentReg);
759 
760  if (!(TII->isThreeOperandsLEA(MI) || hasInefficientLEABaseReg(Base, Index)) ||
761  MBB.computeRegisterLiveness(TRI, X86::EFLAGS, I, 4) !=
763  Segment.getReg() != X86::NoRegister)
764  return;
765 
766  Register DestReg = Dest.getReg();
767  Register BaseReg = Base.getReg();
768  Register IndexReg = Index.getReg();
769 
770  if (MI.getOpcode() == X86::LEA64_32r) {
771  if (BaseReg != 0)
772  BaseReg = TRI->getSubReg(BaseReg, X86::sub_32bit);
773  if (IndexReg != 0)
774  IndexReg = TRI->getSubReg(IndexReg, X86::sub_32bit);
775  }
776 
777  bool IsScale1 = Scale.getImm() == 1;
778  bool IsInefficientBase = isInefficientLEAReg(BaseReg);
779  bool IsInefficientIndex = isInefficientLEAReg(IndexReg);
780 
781  // Skip these cases since it takes more than 2 instructions
782  // to replace the LEA instruction.
783  if (IsInefficientBase && DestReg == BaseReg && !IsScale1)
784  return;
785 
786  LLVM_DEBUG(dbgs() << "FixLEA: Candidate to replace:"; MI.dump(););
787  LLVM_DEBUG(dbgs() << "FixLEA: Replaced by: ";);
788 
789  MachineInstr *NewMI = nullptr;
790 
791  // First try to replace LEA with one or two (for the 3-op LEA case)
792  // add instructions:
793  // 1.lea (%base,%index,1), %base => add %index,%base
794  // 2.lea (%base,%index,1), %index => add %base,%index
795  if (IsScale1 && (DestReg == BaseReg || DestReg == IndexReg)) {
796  unsigned NewOpc = getADDrrFromLEA(MI.getOpcode());
797  if (DestReg != BaseReg)
798  std::swap(BaseReg, IndexReg);
799 
800  if (MI.getOpcode() == X86::LEA64_32r) {
801  // TODO: Do we need the super register implicit use?
802  NewMI = BuildMI(MBB, I, MI.getDebugLoc(), TII->get(NewOpc), DestReg)
803  .addReg(BaseReg)
804  .addReg(IndexReg)
805  .addReg(Base.getReg(), RegState::Implicit)
806  .addReg(Index.getReg(), RegState::Implicit);
807  } else {
808  NewMI = BuildMI(MBB, I, MI.getDebugLoc(), TII->get(NewOpc), DestReg)
809  .addReg(BaseReg)
810  .addReg(IndexReg);
811  }
812  } else if (!IsInefficientBase || (!IsInefficientIndex && IsScale1)) {
813  // If the base is inefficient try switching the index and base operands,
814  // otherwise just break the 3-Ops LEA inst into 2-Ops LEA + ADD instruction:
815  // lea offset(%base,%index,scale),%dst =>
816  // lea (%base,%index,scale); add offset,%dst
817  NewMI = BuildMI(MBB, MI, MI.getDebugLoc(), TII->get(LEAOpcode))
818  .add(Dest)
819  .add(IsInefficientBase ? Index : Base)
820  .add(Scale)
821  .add(IsInefficientBase ? Base : Index)
822  .addImm(0)
823  .add(Segment);
824  LLVM_DEBUG(NewMI->dump(););
825  }
826 
827  // If either replacement succeeded above, add the offset if needed, then
828  // replace the instruction.
829  if (NewMI) {
830  // Create ADD instruction for the Offset in case of 3-Ops LEA.
831  if (hasLEAOffset(Offset)) {
832  if (OptIncDec && Offset.isImm() &&
833  (Offset.getImm() == 1 || Offset.getImm() == -1)) {
834  unsigned NewOpc =
835  getINCDECFromLEA(MI.getOpcode(), Offset.getImm() == 1);
836  NewMI = BuildMI(MBB, I, MI.getDebugLoc(), TII->get(NewOpc), DestReg)
837  .addReg(DestReg);
838  LLVM_DEBUG(NewMI->dump(););
839  } else {
840  unsigned NewOpc = getADDriFromLEA(MI.getOpcode(), Offset);
841  NewMI = BuildMI(MBB, I, MI.getDebugLoc(), TII->get(NewOpc), DestReg)
842  .addReg(DestReg)
843  .add(Offset);
844  LLVM_DEBUG(NewMI->dump(););
845  }
846  }
847 
849  MBB.erase(I);
850  I = NewMI;
851  return;
852  }
853 
854  // Handle the rest of the cases with inefficient base register:
855  assert(DestReg != BaseReg && "DestReg == BaseReg should be handled already!");
856  assert(IsInefficientBase && "efficient base should be handled already!");
857 
858  // FIXME: Handle LEA64_32r.
859  if (LEAOpcode == X86::LEA64_32r)
860  return;
861 
862  // lea (%base,%index,1), %dst => mov %base,%dst; add %index,%dst
863  if (IsScale1 && !hasLEAOffset(Offset)) {
864  bool BIK = Base.isKill() && BaseReg != IndexReg;
865  TII->copyPhysReg(MBB, MI, MI.getDebugLoc(), DestReg, BaseReg, BIK);
866  LLVM_DEBUG(MI.getPrevNode()->dump(););
867 
868  unsigned NewOpc = getADDrrFromLEA(MI.getOpcode());
869  NewMI = BuildMI(MBB, MI, MI.getDebugLoc(), TII->get(NewOpc), DestReg)
870  .addReg(DestReg)
871  .add(Index);
872  LLVM_DEBUG(NewMI->dump(););
873 
875  MBB.erase(I);
876  I = NewMI;
877  return;
878  }
879 
880  // lea offset(%base,%index,scale), %dst =>
881  // lea offset( ,%index,scale), %dst; add %base,%dst
882  NewMI = BuildMI(MBB, MI, MI.getDebugLoc(), TII->get(LEAOpcode))
883  .add(Dest)
884  .addReg(0)
885  .add(Scale)
886  .add(Index)
887  .add(Offset)
888  .add(Segment);
889  LLVM_DEBUG(NewMI->dump(););
890 
891  unsigned NewOpc = getADDrrFromLEA(MI.getOpcode());
892  NewMI = BuildMI(MBB, MI, MI.getDebugLoc(), TII->get(NewOpc), DestReg)
893  .addReg(DestReg)
894  .add(Base);
895  LLVM_DEBUG(NewMI->dump(););
896 
898  MBB.erase(I);
899  I = NewMI;
900 }
hasInefficientLEABaseReg
static bool hasInefficientLEABaseReg(const MachineOperand &Base, const MachineOperand &Index)
Returns true if this LEA uses base an index registers, and the base register is known to be inefficie...
Definition: X86FixupLEAs.cpp:341
llvm::MachineInstr::addRegisterDead
bool addRegisterDead(Register Reg, const TargetRegisterInfo *RegInfo, bool AddIfNotFound=false)
We have determined MI defined a register without a use.
Definition: MachineInstr.cpp:1938
llvm::createX86FixupLEAs
FunctionPass * createX86FixupLEAs()
Return a pass that selectively replaces certain instructions (like add, sub, inc, dec,...
Definition: X86FixupLEAs.cpp:218
MI
IRTranslator LLVM IR MI
Definition: IRTranslator.cpp:105
llvm::MachineInstrBuilder::addImm
const MachineInstrBuilder & addImm(int64_t Val) const
Add a new immediate operand.
Definition: MachineInstrBuilder.h:131
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AllocatorList.h:23
llvm::X86II::getMemoryOperandNo
int getMemoryOperandNo(uint64_t TSFlags)
The function returns the MCInst operand # for the first field of the memory operand.
Definition: X86BaseInfo.h:1095
Reg
unsigned Reg
Definition: MachineSink.cpp:1558
getPreviousInstr
static bool getPreviousInstr(MachineBasicBlock::iterator &I, MachineBasicBlock &MBB)
getPreviousInstr - Given a reference to an instruction in a basic block, return a reference to the pr...
Definition: X86FixupLEAs.cpp:295
X86Subtarget.h
llvm::MachineInstrBuilder::add
const MachineInstrBuilder & add(const MachineOperand &MO) const
Definition: MachineInstrBuilder.h:224
llvm::MachineOperand::setIsKill
void setIsKill(bool Val=true)
Definition: MachineOperand.h:500
Statistic.h
llvm::X86Subtarget
Definition: X86Subtarget.h:52
getSUBrrFromLEA
static unsigned getSUBrrFromLEA(unsigned LEAOpcode)
Definition: X86FixupLEAs.cpp:363
llvm::MachineFunctionPass
MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of pa...
Definition: MachineFunctionPass.h:30
MachineSizeOpts.h
llvm::MachineFunctionProperties
Properties which a MachineFunction may have at a given point in time.
Definition: MachineFunction.h:111
Offset
uint64_t Offset
Definition: ELFObjHandler.cpp:81
llvm::RegState::Kill
@ Kill
The last use of a register.
Definition: MachineInstrBuilder.h:48
TRI
unsigned const TargetRegisterInfo * TRI
Definition: MachineSink.cpp:1559
p
the resulting code requires compare and branches when and if * p
Definition: README.txt:396
llvm::MachineFunctionPass::getAnalysisUsage
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - Subclasses that override getAnalysisUsage must call this.
Definition: MachineFunctionPass.cpp:102
LLVM_DEBUG
#define LLVM_DEBUG(X)
Definition: Debug.h:101
llvm::MachineBasicBlock::erase
instr_iterator erase(instr_iterator I)
Remove an instruction from the instruction list and delete it.
Definition: MachineBasicBlock.cpp:1298
llvm::dbgs
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:163
llvm::RegUsage
@ RegUsage
Definition: SIMachineScheduler.h:33
llvm::MachineOperand::isKill
bool isKill() const
Definition: MachineOperand.h:390
llvm::MachineFunction::substituteDebugValuesForInst
void substituteDebugValuesForInst(const MachineInstr &Old, MachineInstr &New, unsigned MaxOperand=UINT_MAX)
Create substitutions for any tracked values in Old, to point at New.
Definition: MachineFunction.cpp:985
llvm::shouldOptimizeForSize
bool shouldOptimizeForSize(const MachineFunction *MF, ProfileSummaryInfo *PSI, const MachineBlockFrequencyInfo *BFI, PGSOQueryType QueryType=PGSOQueryType::Other)
Returns true if machine function MF is suggested to be size-optimized based on the profile.
Definition: MachineSizeOpts.cpp:183
llvm::MCInstrDesc::TSFlags
uint64_t TSFlags
Definition: MCInstrDesc.h:203
X86.h
llvm::N86::ESP
@ ESP
Definition: X86MCTargetDesc.h:51
E
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
llvm::MachineOperand::getImm
int64_t getImm() const
Definition: MachineOperand.h:537
llvm::X86::AddrScaleAmt
@ AddrScaleAmt
Definition: X86BaseInfo.h:33
INITIALIZE_PASS
#define INITIALIZE_PASS(passName, arg, name, cfg, analysis)
Definition: PassSupport.h:37
llvm::AnalysisUsage
Represent the analysis usage information of a pass.
Definition: PassAnalysisSupport.h:47
TII
const HexagonInstrInfo * TII
Definition: HexagonCopyToCombine.cpp:129
llvm::MCInstrDesc
Describe properties that are true of each instruction in the target description file.
Definition: MCInstrDesc.h:195
llvm::MachineOperand
MachineOperand class - Representation of each machine instruction operand.
Definition: MachineOperand.h:49
llvm::MachineFunctionProperties::set
MachineFunctionProperties & set(Property P)
Definition: MachineFunction.h:180
getADDriFromLEA
static unsigned getADDriFromLEA(unsigned LEAOpcode, const MachineOperand &Offset)
Definition: X86FixupLEAs.cpp:375
llvm::STATISTIC
STATISTIC(NumFunctions, "Total number of functions")
FIXUPLEA_DESC
#define FIXUPLEA_DESC
Definition: X86FixupLEAs.cpp:30
llvm::TargetRegisterInfo::regsOverlap
bool regsOverlap(Register regA, Register regB) const
Returns true if the two registers are equal or alias each other.
Definition: TargetRegisterInfo.h:418
llvm::MachineBasicBlock
Definition: MachineBasicBlock.h:95
llvm::MachineFunctionProperties::Property::NoVRegs
@ NoVRegs
Passes.h
llvm::isInt< 8 >
constexpr bool isInt< 8 >(int64_t x)
Definition: MathExtras.h:367
llvm::MachineFunction::getSubtarget
const TargetSubtargetInfo & getSubtarget() const
getSubtarget - Return the subtarget for which this machine code is being compiled.
Definition: MachineFunction.h:641
LazyMachineBlockFrequencyInfo.h
===- LazyMachineBlockFrequencyInfo.h - Lazy Block Frequency -*- C++ -*–===//
llvm::X86::AddrBaseReg
@ AddrBaseReg
Definition: X86BaseInfo.h:32
getADDrrFromLEA
static unsigned getADDrrFromLEA(unsigned LEAOpcode)
Definition: X86FixupLEAs.cpp:351
TargetSchedule.h
llvm::X86II::getOperandBias
unsigned getOperandBias(const MCInstrDesc &Desc)
Compute whether all of the def operands are repeated in the uses and therefore should be skipped.
Definition: X86BaseInfo.h:1055
getINCDECFromLEA
static unsigned getINCDECFromLEA(unsigned LEAOpcode, bool IsINC)
Definition: X86FixupLEAs.cpp:389
llvm::TargetSchedModel
Provide an instruction scheduling machine model to CodeGen passes.
Definition: TargetSchedule.h:30
Index
uint32_t Index
Definition: ELFObjHandler.cpp:84
llvm::MachineOperand::isReg
bool isReg() const
isReg - Tests if this is a MO_Register operand.
Definition: MachineOperand.h:321
llvm::MachineInstr
Representation of each machine instruction.
Definition: MachineInstr.h:64
ProfileSummaryInfo.h
llvm::ARM_MB::ST
@ ST
Definition: ARMBaseInfo.h:73
llvm::X86::AddrIndexReg
@ AddrIndexReg
Definition: X86BaseInfo.h:34
isLEA
static bool isLEA(unsigned Opcode)
Definition: X86FixupLEAs.cpp:220
I
#define I(x, y, z)
Definition: MD5.cpp:59
llvm::ProfileSummaryInfoWrapperPass
An analysis pass based on legacy pass manager to deliver ProfileSummaryInfo.
Definition: ProfileSummaryInfo.h:193
MachineFunctionPass.h
FIXUPLEA_NAME
#define FIXUPLEA_NAME
Definition: X86FixupLEAs.cpp:31
assert
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
std::swap
void swap(llvm::BitVector &LHS, llvm::BitVector &RHS)
Implement std::swap in terms of BitVector swap.
Definition: BitVector.h:840
llvm::MachineBasicBlock::getParent
const MachineFunction * getParent() const
Return the MachineFunction containing this basic block.
Definition: MachineBasicBlock.h:225
hasLEAOffset
static bool hasLEAOffset(const MachineOperand &Offset)
Definition: X86FixupLEAs.cpp:347
llvm::X86::AddrDisp
@ AddrDisp
Definition: X86BaseInfo.h:35
llvm::MachineInstrBuilder::addReg
const MachineInstrBuilder & addReg(Register RegNo, unsigned flags=0, unsigned SubReg=0) const
Add a new virtual register operand.
Definition: MachineInstrBuilder.h:97
llvm::MachineOperand::getReg
Register getReg() const
getReg - Returns the register number.
Definition: MachineOperand.h:360
llvm::LazyMachineBlockFrequencyInfoPass
This is an alternative analysis pass to MachineBlockFrequencyInfo.
Definition: LazyMachineBlockFrequencyInfo.h:37
llvm::MachineBasicBlock::LQR_Dead
@ LQR_Dead
Register is known to be fully dead.
Definition: MachineBasicBlock.h:1019
llvm::MachineFunction
Definition: MachineFunction.h:241
llvm::MachineInstr::dump
void dump() const
Definition: MachineInstr.cpp:1521
llvm::X86InstrInfo
Definition: X86InstrInfo.h:130
llvm::X86::AddrSegmentReg
@ AddrSegmentReg
AddrSegmentReg - The operand # of the segment in the memory operand.
Definition: X86BaseInfo.h:38
llvm::MachineBasicBlock::iterator
MachineInstrBundleIterator< MachineInstr > iterator
Definition: MachineBasicBlock.h:233
llvm::StringRef
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:57
MBBI
MachineBasicBlock MachineBasicBlock::iterator MBBI
Definition: AArch64SLSHardening.cpp:75
llvm_unreachable
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
Definition: ErrorHandling.h:134
llvm::MachineOperand::isDef
bool isDef() const
Definition: MachineOperand.h:375
llvm::Pass::dump
void dump() const
Definition: Pass.cpp:131
llvm::Register
Wrapper class representing virtual and physical registers.
Definition: Register.h:19
llvm::Function::hasOptSize
bool hasOptSize() const
Optimize this function for size (-Os) or minimum size (-Oz).
Definition: Function.h:661
llvm::MachineBasicBlock::isPredecessor
bool isPredecessor(const MachineBasicBlock *MBB) const
Return true if the specified MBB is a predecessor of this block.
Definition: MachineBasicBlock.cpp:908
MBB
MachineBasicBlock & MBB
Definition: AArch64SLSHardening.cpp:74
llvm::MachineFunction::getFunction
Function & getFunction()
Return the LLVM function that this machine code represents.
Definition: MachineFunction.h:607
llvm::RegState::Implicit
@ Implicit
Not emitted register (e.g. carry, or temporary result).
Definition: MachineInstrBuilder.h:46
llvm::MachineBasicBlock::computeRegisterLiveness
LivenessQueryResult computeRegisterLiveness(const TargetRegisterInfo *TRI, MCRegister Reg, const_iterator Before, unsigned Neighborhood=10) const
Return whether (physical) register Reg has been defined and not killed as of just before Before.
Definition: MachineBasicBlock.cpp:1484
llvm::MachineOperand::isImm
bool isImm() const
isImm - Tests if this is a MO_Immediate operand.
Definition: MachineOperand.h:323
llvm::MachineBasicBlock::begin
iterator begin()
Definition: MachineBasicBlock.h:268
MachineInstrBuilder.h
llvm::BuildMI
MachineInstrBuilder BuildMI(MachineFunction &MF, const DebugLoc &DL, const MCInstrDesc &MCID)
Builder interface. Specify how to create the initial instruction itself.
Definition: MachineInstrBuilder.h:328
llvm::TargetRegisterInfo::getSubReg
MCRegister getSubReg(MCRegister Reg, unsigned Idx) const
Returns the physical register number of sub-register "Index" for physical register RegNo.
Definition: TargetRegisterInfo.h:1094
llvm::FunctionPass
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:298
llvm::AnalysisUsage::addRequired
AnalysisUsage & addRequired()
Definition: PassAnalysisSupport.h:75
raw_ostream.h
X86InstrInfo.h
llvm::MachineInstrBundleIterator
MachineBasicBlock iterator that automatically skips over MIs that are inside bundles (i....
Definition: MachineInstrBundleIterator.h:108
llvm::HexagonInstrInfo::copyPhysReg
void copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator I, const DebugLoc &DL, MCRegister DestReg, MCRegister SrcReg, bool KillSrc) const override
Emit instructions to copy a pair of physical registers.
Definition: HexagonInstrInfo.cpp:810
Debug.h
llvm::MachineBasicBlock::end
iterator end()
Definition: MachineBasicBlock.h:270
isInefficientLEAReg
static bool isInefficientLEAReg(unsigned Reg)
Definition: X86FixupLEAs.cpp:332
llvm::sampleprof::Base
@ Base
Definition: Discriminator.h:58
llvm::X86RegisterInfo
Definition: X86RegisterInfo.h:24
llvm::Intrinsic::ID
unsigned ID
Definition: TargetTransformInfo.h:38