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1//===- ARMInstructionSelector.cpp ----------------------------*- C++ -*-==//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-exception6//7//===----------------------------------------------------------------------===//8/// \file9/// This file implements the targeting of the InstructionSelector class for ARM.10/// \todo This should be generated by TableGen.11//===----------------------------------------------------------------------===//12 13#include "ARMRegisterBankInfo.h"14#include "ARMSubtarget.h"15#include "ARMTargetMachine.h"16#include "llvm/CodeGen/GlobalISel/GIMatchTableExecutorImpl.h"17#include "llvm/CodeGen/GlobalISel/GenericMachineInstrs.h"18#include "llvm/CodeGen/GlobalISel/InstructionSelector.h"19#include "llvm/CodeGen/MachineConstantPool.h"20#include "llvm/CodeGen/MachineRegisterInfo.h"21#include "llvm/Support/Debug.h"22 23#define DEBUG_TYPE "arm-isel"24 25using namespace llvm;26 27namespace {28 29#define GET_GLOBALISEL_PREDICATE_BITSET30#include "ARMGenGlobalISel.inc"31#undef GET_GLOBALISEL_PREDICATE_BITSET32 33class ARMInstructionSelector : public InstructionSelector {34public:35  ARMInstructionSelector(const ARMBaseTargetMachine &TM, const ARMSubtarget &STI,36                         const ARMRegisterBankInfo &RBI);37 38  bool select(MachineInstr &I) override;39  static const char *getName() { return DEBUG_TYPE; }40 41private:42  bool selectImpl(MachineInstr &I, CodeGenCoverage &CoverageInfo) const;43 44  struct CmpConstants;45  struct InsertInfo;46 47  bool selectCmp(CmpConstants Helper, MachineInstrBuilder &MIB,48                 MachineRegisterInfo &MRI) const;49 50  // Helper for inserting a comparison sequence that sets \p ResReg to either 151  // if \p LHSReg and \p RHSReg are in the relationship defined by \p Cond, or52  // \p PrevRes otherwise. In essence, it computes PrevRes OR (LHS Cond RHS).53  bool insertComparison(CmpConstants Helper, InsertInfo I, unsigned ResReg,54                        ARMCC::CondCodes Cond, unsigned LHSReg, unsigned RHSReg,55                        unsigned PrevRes) const;56 57  // Set \p DestReg to \p Constant.58  void putConstant(InsertInfo I, unsigned DestReg, unsigned Constant) const;59 60  bool selectGlobal(MachineInstrBuilder &MIB, MachineRegisterInfo &MRI) const;61  bool selectSelect(MachineInstrBuilder &MIB, MachineRegisterInfo &MRI) const;62  bool selectShift(unsigned ShiftOpc, MachineInstrBuilder &MIB) const;63 64  // Check if the types match and both operands have the expected size and65  // register bank.66  bool validOpRegPair(MachineRegisterInfo &MRI, unsigned LHS, unsigned RHS,67                      unsigned ExpectedSize, unsigned ExpectedRegBankID) const;68 69  // Check if the register has the expected size and register bank.70  bool validReg(MachineRegisterInfo &MRI, unsigned Reg, unsigned ExpectedSize,71                unsigned ExpectedRegBankID) const;72 73  const ARMBaseInstrInfo &TII;74  const ARMBaseRegisterInfo &TRI;75  const ARMBaseTargetMachine &TM;76  const ARMRegisterBankInfo &RBI;77  const ARMSubtarget &STI;78 79  // FIXME: This is necessary because DAGISel uses "Subtarget->" and GlobalISel80  // uses "STI." in the code generated by TableGen. If we want to reuse some of81  // the custom C++ predicates written for DAGISel, we need to have both around.82  const ARMSubtarget *Subtarget = &STI;83 84  // Store the opcodes that we might need, so we don't have to check what kind85  // of subtarget (ARM vs Thumb) we have all the time.86  struct OpcodeCache {87    unsigned ZEXT16;88    unsigned SEXT16;89 90    unsigned ZEXT8;91    unsigned SEXT8;92 93    // Used for implementing ZEXT/SEXT from i194    unsigned AND;95    unsigned RSB;96 97    unsigned STORE32;98    unsigned LOAD32;99 100    unsigned STORE16;101    unsigned LOAD16;102 103    unsigned STORE8;104    unsigned LOAD8;105 106    unsigned ADDrr;107    unsigned ADDri;108 109    // Used for G_ICMP110    unsigned CMPrr;111    unsigned MOVi;112    unsigned MOVCCi;113 114    // Used for G_SELECT115    unsigned MOVCCr;116 117    unsigned TSTri;118    unsigned Bcc;119 120    // Used for G_GLOBAL_VALUE121    unsigned MOVi32imm;122    unsigned ConstPoolLoad;123    unsigned MOV_ga_pcrel;124    unsigned LDRLIT_ga_pcrel;125    unsigned LDRLIT_ga_abs;126 127    OpcodeCache(const ARMSubtarget &STI);128  } const Opcodes;129 130  // Select the opcode for simple extensions (that translate to a single SXT/UXT131  // instruction). Extension operations more complicated than that should not132  // invoke this. Returns the original opcode if it doesn't know how to select a133  // better one.134  unsigned selectSimpleExtOpc(unsigned Opc, unsigned Size) const;135 136  // Select the opcode for simple loads and stores. Returns the original opcode137  // if it doesn't know how to select a better one.138  unsigned selectLoadStoreOpCode(unsigned Opc, unsigned RegBank,139                                 unsigned Size) const;140 141  void renderVFPF32Imm(MachineInstrBuilder &New, const MachineInstr &Old,142                       int OpIdx = -1) const;143  void renderVFPF64Imm(MachineInstrBuilder &New, const MachineInstr &Old,144                       int OpIdx = -1) const;145  void renderInvertedImm(MachineInstrBuilder &MIB, const MachineInstr &MI,146                         int OpIdx = -1) const;147 148#define GET_GLOBALISEL_PREDICATES_DECL149#include "ARMGenGlobalISel.inc"150#undef GET_GLOBALISEL_PREDICATES_DECL151 152// We declare the temporaries used by selectImpl() in the class to minimize the153// cost of constructing placeholder values.154#define GET_GLOBALISEL_TEMPORARIES_DECL155#include "ARMGenGlobalISel.inc"156#undef GET_GLOBALISEL_TEMPORARIES_DECL157};158} // end anonymous namespace159 160namespace llvm {161InstructionSelector *162createARMInstructionSelector(const ARMBaseTargetMachine &TM,163                             const ARMSubtarget &STI,164                             const ARMRegisterBankInfo &RBI) {165  return new ARMInstructionSelector(TM, STI, RBI);166}167}168 169#define GET_GLOBALISEL_IMPL170#include "ARMGenGlobalISel.inc"171#undef GET_GLOBALISEL_IMPL172 173ARMInstructionSelector::ARMInstructionSelector(const ARMBaseTargetMachine &TM,174                                               const ARMSubtarget &STI,175                                               const ARMRegisterBankInfo &RBI)176    : TII(*STI.getInstrInfo()), TRI(*STI.getRegisterInfo()), TM(TM), RBI(RBI),177      STI(STI), Opcodes(STI),178#define GET_GLOBALISEL_PREDICATES_INIT179#include "ARMGenGlobalISel.inc"180#undef GET_GLOBALISEL_PREDICATES_INIT181#define GET_GLOBALISEL_TEMPORARIES_INIT182#include "ARMGenGlobalISel.inc"183#undef GET_GLOBALISEL_TEMPORARIES_INIT184{185}186 187static const TargetRegisterClass *guessRegClass(unsigned Reg,188                                                MachineRegisterInfo &MRI,189                                                const TargetRegisterInfo &TRI,190                                                const RegisterBankInfo &RBI) {191  const RegisterBank *RegBank = RBI.getRegBank(Reg, MRI, TRI);192  assert(RegBank && "Can't get reg bank for virtual register");193 194  const unsigned Size = MRI.getType(Reg).getSizeInBits();195  assert((RegBank->getID() == ARM::GPRRegBankID ||196          RegBank->getID() == ARM::FPRRegBankID) &&197         "Unsupported reg bank");198 199  if (RegBank->getID() == ARM::FPRRegBankID) {200    if (Size == 32)201      return &ARM::SPRRegClass;202    else if (Size == 64)203      return &ARM::DPRRegClass;204    else if (Size == 128)205      return &ARM::QPRRegClass;206    else207      llvm_unreachable("Unsupported destination size");208  }209 210  return &ARM::GPRRegClass;211}212 213static bool selectCopy(MachineInstr &I, const TargetInstrInfo &TII,214                       MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,215                       const RegisterBankInfo &RBI) {216  Register DstReg = I.getOperand(0).getReg();217  if (DstReg.isPhysical())218    return true;219 220  const TargetRegisterClass *RC = guessRegClass(DstReg, MRI, TRI, RBI);221 222  // No need to constrain SrcReg. It will get constrained when223  // we hit another of its uses or its defs.224  // Copies do not have constraints.225  if (!RBI.constrainGenericRegister(DstReg, *RC, MRI)) {226    LLVM_DEBUG(dbgs() << "Failed to constrain " << TII.getName(I.getOpcode())227                      << " operand\n");228    return false;229  }230  return true;231}232 233static bool selectMergeValues(MachineInstrBuilder &MIB,234                              const ARMBaseInstrInfo &TII,235                              MachineRegisterInfo &MRI,236                              const TargetRegisterInfo &TRI,237                              const RegisterBankInfo &RBI) {238  assert(TII.getSubtarget().hasVFP2Base() && "Can't select merge without VFP");239 240  // We only support G_MERGE_VALUES as a way to stick together two scalar GPRs241  // into one DPR.242  Register VReg0 = MIB.getReg(0);243  (void)VReg0;244  assert(MRI.getType(VReg0).getSizeInBits() == 64 &&245         RBI.getRegBank(VReg0, MRI, TRI)->getID() == ARM::FPRRegBankID &&246         "Unsupported operand for G_MERGE_VALUES");247  Register VReg1 = MIB.getReg(1);248  (void)VReg1;249  assert(MRI.getType(VReg1).getSizeInBits() == 32 &&250         RBI.getRegBank(VReg1, MRI, TRI)->getID() == ARM::GPRRegBankID &&251         "Unsupported operand for G_MERGE_VALUES");252  Register VReg2 = MIB.getReg(2);253  (void)VReg2;254  assert(MRI.getType(VReg2).getSizeInBits() == 32 &&255         RBI.getRegBank(VReg2, MRI, TRI)->getID() == ARM::GPRRegBankID &&256         "Unsupported operand for G_MERGE_VALUES");257 258  MIB->setDesc(TII.get(ARM::VMOVDRR));259  MIB.add(predOps(ARMCC::AL));260 261  return true;262}263 264static bool selectUnmergeValues(MachineInstrBuilder &MIB,265                                const ARMBaseInstrInfo &TII,266                                MachineRegisterInfo &MRI,267                                const TargetRegisterInfo &TRI,268                                const RegisterBankInfo &RBI) {269  assert(TII.getSubtarget().hasVFP2Base() &&270         "Can't select unmerge without VFP");271 272  // We only support G_UNMERGE_VALUES as a way to break up one DPR into two273  // GPRs.274  Register VReg0 = MIB.getReg(0);275  (void)VReg0;276  assert(MRI.getType(VReg0).getSizeInBits() == 32 &&277         RBI.getRegBank(VReg0, MRI, TRI)->getID() == ARM::GPRRegBankID &&278         "Unsupported operand for G_UNMERGE_VALUES");279  Register VReg1 = MIB.getReg(1);280  (void)VReg1;281  assert(MRI.getType(VReg1).getSizeInBits() == 32 &&282         RBI.getRegBank(VReg1, MRI, TRI)->getID() == ARM::GPRRegBankID &&283         "Unsupported operand for G_UNMERGE_VALUES");284  Register VReg2 = MIB.getReg(2);285  (void)VReg2;286  assert(MRI.getType(VReg2).getSizeInBits() == 64 &&287         RBI.getRegBank(VReg2, MRI, TRI)->getID() == ARM::FPRRegBankID &&288         "Unsupported operand for G_UNMERGE_VALUES");289 290  MIB->setDesc(TII.get(ARM::VMOVRRD));291  MIB.add(predOps(ARMCC::AL));292 293  return true;294}295 296ARMInstructionSelector::OpcodeCache::OpcodeCache(const ARMSubtarget &STI) {297  bool isThumb = STI.isThumb();298 299  using namespace TargetOpcode;300 301#define STORE_OPCODE(VAR, OPC) VAR = isThumb ? ARM::t2##OPC : ARM::OPC302  STORE_OPCODE(SEXT16, SXTH);303  STORE_OPCODE(ZEXT16, UXTH);304 305  STORE_OPCODE(SEXT8, SXTB);306  STORE_OPCODE(ZEXT8, UXTB);307 308  STORE_OPCODE(AND, ANDri);309  STORE_OPCODE(RSB, RSBri);310 311  STORE_OPCODE(STORE32, STRi12);312  STORE_OPCODE(LOAD32, LDRi12);313 314  // LDRH/STRH are special...315  STORE16 = isThumb ? ARM::t2STRHi12 : ARM::STRH;316  LOAD16 = isThumb ? ARM::t2LDRHi12 : ARM::LDRH;317 318  STORE_OPCODE(STORE8, STRBi12);319  STORE_OPCODE(LOAD8, LDRBi12);320 321  STORE_OPCODE(ADDrr, ADDrr);322  STORE_OPCODE(ADDri, ADDri);323 324  STORE_OPCODE(CMPrr, CMPrr);325  STORE_OPCODE(MOVi, MOVi);326  STORE_OPCODE(MOVCCi, MOVCCi);327 328  STORE_OPCODE(MOVCCr, MOVCCr);329 330  STORE_OPCODE(TSTri, TSTri);331  STORE_OPCODE(Bcc, Bcc);332 333  STORE_OPCODE(MOVi32imm, MOVi32imm);334  ConstPoolLoad = isThumb ? ARM::t2LDRpci : ARM::LDRi12;335  STORE_OPCODE(MOV_ga_pcrel, MOV_ga_pcrel);336  LDRLIT_ga_pcrel = isThumb ? ARM::tLDRLIT_ga_pcrel : ARM::LDRLIT_ga_pcrel;337  LDRLIT_ga_abs = isThumb ? ARM::tLDRLIT_ga_abs : ARM::LDRLIT_ga_abs;338#undef MAP_OPCODE339}340 341unsigned ARMInstructionSelector::selectSimpleExtOpc(unsigned Opc,342                                                    unsigned Size) const {343  using namespace TargetOpcode;344 345  if (Size != 8 && Size != 16)346    return Opc;347 348  if (Opc == G_SEXT)349    return Size == 8 ? Opcodes.SEXT8 : Opcodes.SEXT16;350 351  if (Opc == G_ZEXT)352    return Size == 8 ? Opcodes.ZEXT8 : Opcodes.ZEXT16;353 354  return Opc;355}356 357unsigned ARMInstructionSelector::selectLoadStoreOpCode(unsigned Opc,358                                                       unsigned RegBank,359                                                       unsigned Size) const {360  bool isStore = Opc == TargetOpcode::G_STORE;361 362  if (RegBank == ARM::GPRRegBankID) {363    switch (Size) {364    case 1:365    case 8:366      return isStore ? Opcodes.STORE8 : Opcodes.LOAD8;367    case 16:368      return isStore ? Opcodes.STORE16 : Opcodes.LOAD16;369    case 32:370      return isStore ? Opcodes.STORE32 : Opcodes.LOAD32;371    default:372      return Opc;373    }374  }375 376  if (RegBank == ARM::FPRRegBankID) {377    switch (Size) {378    case 32:379      return isStore ? ARM::VSTRS : ARM::VLDRS;380    case 64:381      return isStore ? ARM::VSTRD : ARM::VLDRD;382    default:383      return Opc;384    }385  }386 387  return Opc;388}389 390// When lowering comparisons, we sometimes need to perform two compares instead391// of just one. Get the condition codes for both comparisons. If only one is392// needed, the second member of the pair is ARMCC::AL.393static std::pair<ARMCC::CondCodes, ARMCC::CondCodes>394getComparePreds(CmpInst::Predicate Pred) {395  std::pair<ARMCC::CondCodes, ARMCC::CondCodes> Preds = {ARMCC::AL, ARMCC::AL};396  switch (Pred) {397  case CmpInst::FCMP_ONE:398    Preds = {ARMCC::GT, ARMCC::MI};399    break;400  case CmpInst::FCMP_UEQ:401    Preds = {ARMCC::EQ, ARMCC::VS};402    break;403  case CmpInst::ICMP_EQ:404  case CmpInst::FCMP_OEQ:405    Preds.first = ARMCC::EQ;406    break;407  case CmpInst::ICMP_SGT:408  case CmpInst::FCMP_OGT:409    Preds.first = ARMCC::GT;410    break;411  case CmpInst::ICMP_SGE:412  case CmpInst::FCMP_OGE:413    Preds.first = ARMCC::GE;414    break;415  case CmpInst::ICMP_UGT:416  case CmpInst::FCMP_UGT:417    Preds.first = ARMCC::HI;418    break;419  case CmpInst::FCMP_OLT:420    Preds.first = ARMCC::MI;421    break;422  case CmpInst::ICMP_ULE:423  case CmpInst::FCMP_OLE:424    Preds.first = ARMCC::LS;425    break;426  case CmpInst::FCMP_ORD:427    Preds.first = ARMCC::VC;428    break;429  case CmpInst::FCMP_UNO:430    Preds.first = ARMCC::VS;431    break;432  case CmpInst::FCMP_UGE:433    Preds.first = ARMCC::PL;434    break;435  case CmpInst::ICMP_SLT:436  case CmpInst::FCMP_ULT:437    Preds.first = ARMCC::LT;438    break;439  case CmpInst::ICMP_SLE:440  case CmpInst::FCMP_ULE:441    Preds.first = ARMCC::LE;442    break;443  case CmpInst::FCMP_UNE:444  case CmpInst::ICMP_NE:445    Preds.first = ARMCC::NE;446    break;447  case CmpInst::ICMP_UGE:448    Preds.first = ARMCC::HS;449    break;450  case CmpInst::ICMP_ULT:451    Preds.first = ARMCC::LO;452    break;453  default:454    break;455  }456  assert(Preds.first != ARMCC::AL && "No comparisons needed?");457  return Preds;458}459 460struct ARMInstructionSelector::CmpConstants {461  CmpConstants(unsigned CmpOpcode, unsigned FlagsOpcode, unsigned SelectOpcode,462               unsigned OpRegBank, unsigned OpSize)463      : ComparisonOpcode(CmpOpcode), ReadFlagsOpcode(FlagsOpcode),464        SelectResultOpcode(SelectOpcode), OperandRegBankID(OpRegBank),465        OperandSize(OpSize) {}466 467  // The opcode used for performing the comparison.468  const unsigned ComparisonOpcode;469 470  // The opcode used for reading the flags set by the comparison. May be471  // ARM::INSTRUCTION_LIST_END if we don't need to read the flags.472  const unsigned ReadFlagsOpcode;473 474  // The opcode used for materializing the result of the comparison.475  const unsigned SelectResultOpcode;476 477  // The assumed register bank ID for the operands.478  const unsigned OperandRegBankID;479 480  // The assumed size in bits for the operands.481  const unsigned OperandSize;482};483 484struct ARMInstructionSelector::InsertInfo {485  InsertInfo(MachineInstrBuilder &MIB)486      : MBB(*MIB->getParent()), InsertBefore(std::next(MIB->getIterator())),487        DbgLoc(MIB->getDebugLoc()) {}488 489  MachineBasicBlock &MBB;490  const MachineBasicBlock::instr_iterator InsertBefore;491  const DebugLoc &DbgLoc;492};493 494void ARMInstructionSelector::putConstant(InsertInfo I, unsigned DestReg,495                                         unsigned Constant) const {496  (void)BuildMI(I.MBB, I.InsertBefore, I.DbgLoc, TII.get(Opcodes.MOVi))497      .addDef(DestReg)498      .addImm(Constant)499      .add(predOps(ARMCC::AL))500      .add(condCodeOp());501}502 503bool ARMInstructionSelector::validOpRegPair(MachineRegisterInfo &MRI,504                                            unsigned LHSReg, unsigned RHSReg,505                                            unsigned ExpectedSize,506                                            unsigned ExpectedRegBankID) const {507  return MRI.getType(LHSReg) == MRI.getType(RHSReg) &&508         validReg(MRI, LHSReg, ExpectedSize, ExpectedRegBankID) &&509         validReg(MRI, RHSReg, ExpectedSize, ExpectedRegBankID);510}511 512bool ARMInstructionSelector::validReg(MachineRegisterInfo &MRI, unsigned Reg,513                                      unsigned ExpectedSize,514                                      unsigned ExpectedRegBankID) const {515  if (MRI.getType(Reg).getSizeInBits() != ExpectedSize) {516    LLVM_DEBUG(dbgs() << "Unexpected size for register");517    return false;518  }519 520  if (RBI.getRegBank(Reg, MRI, TRI)->getID() != ExpectedRegBankID) {521    LLVM_DEBUG(dbgs() << "Unexpected register bank for register");522    return false;523  }524 525  return true;526}527 528bool ARMInstructionSelector::selectCmp(CmpConstants Helper,529                                       MachineInstrBuilder &MIB,530                                       MachineRegisterInfo &MRI) const {531  const InsertInfo I(MIB);532 533  auto ResReg = MIB.getReg(0);534  if (!validReg(MRI, ResReg, 1, ARM::GPRRegBankID))535    return false;536 537  auto Cond =538      static_cast<CmpInst::Predicate>(MIB->getOperand(1).getPredicate());539  if (Cond == CmpInst::FCMP_TRUE || Cond == CmpInst::FCMP_FALSE) {540    putConstant(I, ResReg, Cond == CmpInst::FCMP_TRUE ? 1 : 0);541    MIB->eraseFromParent();542    return true;543  }544 545  auto LHSReg = MIB.getReg(2);546  auto RHSReg = MIB.getReg(3);547  if (!validOpRegPair(MRI, LHSReg, RHSReg, Helper.OperandSize,548                      Helper.OperandRegBankID))549    return false;550 551  auto ARMConds = getComparePreds(Cond);552  auto ZeroReg = MRI.createVirtualRegister(&ARM::GPRRegClass);553  putConstant(I, ZeroReg, 0);554 555  if (ARMConds.second == ARMCC::AL) {556    // Simple case, we only need one comparison and we're done.557    if (!insertComparison(Helper, I, ResReg, ARMConds.first, LHSReg, RHSReg,558                          ZeroReg))559      return false;560  } else {561    // Not so simple, we need two successive comparisons.562    auto IntermediateRes = MRI.createVirtualRegister(&ARM::GPRRegClass);563    if (!insertComparison(Helper, I, IntermediateRes, ARMConds.first, LHSReg,564                          RHSReg, ZeroReg))565      return false;566    if (!insertComparison(Helper, I, ResReg, ARMConds.second, LHSReg, RHSReg,567                          IntermediateRes))568      return false;569  }570 571  MIB->eraseFromParent();572  return true;573}574 575bool ARMInstructionSelector::insertComparison(CmpConstants Helper, InsertInfo I,576                                              unsigned ResReg,577                                              ARMCC::CondCodes Cond,578                                              unsigned LHSReg, unsigned RHSReg,579                                              unsigned PrevRes) const {580  // Perform the comparison.581  auto CmpI =582      BuildMI(I.MBB, I.InsertBefore, I.DbgLoc, TII.get(Helper.ComparisonOpcode))583          .addUse(LHSReg)584          .addUse(RHSReg)585          .add(predOps(ARMCC::AL));586  if (!constrainSelectedInstRegOperands(*CmpI, TII, TRI, RBI))587    return false;588 589  // Read the comparison flags (if necessary).590  if (Helper.ReadFlagsOpcode != ARM::INSTRUCTION_LIST_END) {591    auto ReadI = BuildMI(I.MBB, I.InsertBefore, I.DbgLoc,592                         TII.get(Helper.ReadFlagsOpcode))593                     .add(predOps(ARMCC::AL));594    if (!constrainSelectedInstRegOperands(*ReadI, TII, TRI, RBI))595      return false;596  }597 598  // Select either 1 or the previous result based on the value of the flags.599  auto Mov1I = BuildMI(I.MBB, I.InsertBefore, I.DbgLoc,600                       TII.get(Helper.SelectResultOpcode))601                   .addDef(ResReg)602                   .addUse(PrevRes)603                   .addImm(1)604                   .add(predOps(Cond, ARM::CPSR));605  if (!constrainSelectedInstRegOperands(*Mov1I, TII, TRI, RBI))606    return false;607 608  return true;609}610 611bool ARMInstructionSelector::selectGlobal(MachineInstrBuilder &MIB,612                                          MachineRegisterInfo &MRI) const {613  if ((STI.isROPI() || STI.isRWPI()) && !STI.isTargetELF()) {614    LLVM_DEBUG(dbgs() << "ROPI and RWPI only supported for ELF\n");615    return false;616  }617 618  auto GV = MIB->getOperand(1).getGlobal();619  if (GV->isThreadLocal()) {620    LLVM_DEBUG(dbgs() << "TLS variables not supported yet\n");621    return false;622  }623 624  auto &MBB = *MIB->getParent();625  auto &MF = *MBB.getParent();626 627  bool UseMovt = STI.useMovt();628 629  LLT PtrTy = MRI.getType(MIB->getOperand(0).getReg());630  const Align Alignment(4);631 632  auto addOpsForConstantPoolLoad = [&MF, Alignment, PtrTy](633                                       MachineInstrBuilder &MIB,634                                       const GlobalValue *GV, bool IsSBREL) {635    assert((MIB->getOpcode() == ARM::LDRi12 ||636            MIB->getOpcode() == ARM::t2LDRpci) &&637           "Unsupported instruction");638    auto ConstPool = MF.getConstantPool();639    auto CPIndex =640        // For SB relative entries we need a target-specific constant pool.641        // Otherwise, just use a regular constant pool entry.642        IsSBREL643            ? ConstPool->getConstantPoolIndex(644                  ARMConstantPoolConstant::Create(GV, ARMCP::SBREL), Alignment)645            : ConstPool->getConstantPoolIndex(GV, Alignment);646    MIB.addConstantPoolIndex(CPIndex, /*Offset*/ 0, /*TargetFlags*/ 0)647        .addMemOperand(MF.getMachineMemOperand(648            MachinePointerInfo::getConstantPool(MF), MachineMemOperand::MOLoad,649            PtrTy, Alignment));650    if (MIB->getOpcode() == ARM::LDRi12)651      MIB.addImm(0);652    MIB.add(predOps(ARMCC::AL));653  };654 655  auto addGOTMemOperand = [this, &MF, Alignment](MachineInstrBuilder &MIB) {656    MIB.addMemOperand(MF.getMachineMemOperand(657        MachinePointerInfo::getGOT(MF), MachineMemOperand::MOLoad,658        TM.getProgramPointerSize(), Alignment));659  };660 661  if (TM.isPositionIndependent()) {662    bool Indirect = STI.isGVIndirectSymbol(GV);663 664    // For ARM mode, we have different pseudoinstructions for direct accesses665    // and indirect accesses, and the ones for indirect accesses include the666    // load from GOT. For Thumb mode, we use the same pseudoinstruction for both667    // direct and indirect accesses, and we need to manually generate the load668    // from GOT.669    bool UseOpcodeThatLoads = Indirect && !STI.isThumb();670 671    // FIXME: Taking advantage of MOVT for ELF is pretty involved, so we don't672    // support it yet. See PR28229.673    unsigned Opc =674        UseMovt && !STI.isTargetELF()675            ? (UseOpcodeThatLoads ? (unsigned)ARM::MOV_ga_pcrel_ldr676                                  : Opcodes.MOV_ga_pcrel)677            : (UseOpcodeThatLoads ? (unsigned)ARM::LDRLIT_ga_pcrel_ldr678                                  : Opcodes.LDRLIT_ga_pcrel);679    MIB->setDesc(TII.get(Opc));680 681    int TargetFlags = ARMII::MO_NO_FLAG;682    if (STI.isTargetDarwin())683      TargetFlags |= ARMII::MO_NONLAZY;684    if (STI.isGVInGOT(GV))685      TargetFlags |= ARMII::MO_GOT;686    MIB->getOperand(1).setTargetFlags(TargetFlags);687 688    if (Indirect) {689      if (!UseOpcodeThatLoads) {690        auto ResultReg = MIB.getReg(0);691        auto AddressReg = MRI.createVirtualRegister(&ARM::GPRRegClass);692 693        MIB->getOperand(0).setReg(AddressReg);694 695        auto InsertBefore = std::next(MIB->getIterator());696        auto MIBLoad = BuildMI(MBB, InsertBefore, MIB->getDebugLoc(),697                               TII.get(Opcodes.LOAD32))698                           .addDef(ResultReg)699                           .addReg(AddressReg)700                           .addImm(0)701                           .add(predOps(ARMCC::AL));702        addGOTMemOperand(MIBLoad);703 704        if (!constrainSelectedInstRegOperands(*MIBLoad, TII, TRI, RBI))705          return false;706      } else {707        addGOTMemOperand(MIB);708      }709    }710 711    return constrainSelectedInstRegOperands(*MIB, TII, TRI, RBI);712  }713 714  bool isReadOnly = STI.getTargetLowering()->isReadOnly(GV);715  if (STI.isROPI() && isReadOnly) {716    unsigned Opc = UseMovt ? Opcodes.MOV_ga_pcrel : Opcodes.LDRLIT_ga_pcrel;717    MIB->setDesc(TII.get(Opc));718    return constrainSelectedInstRegOperands(*MIB, TII, TRI, RBI);719  }720  if (STI.isRWPI() && !isReadOnly) {721    auto Offset = MRI.createVirtualRegister(&ARM::GPRRegClass);722    MachineInstrBuilder OffsetMIB;723    if (UseMovt) {724      OffsetMIB = BuildMI(MBB, *MIB, MIB->getDebugLoc(),725                          TII.get(Opcodes.MOVi32imm), Offset);726      OffsetMIB.addGlobalAddress(GV, /*Offset*/ 0, ARMII::MO_SBREL);727    } else {728      // Load the offset from the constant pool.729      OffsetMIB = BuildMI(MBB, *MIB, MIB->getDebugLoc(),730                          TII.get(Opcodes.ConstPoolLoad), Offset);731      addOpsForConstantPoolLoad(OffsetMIB, GV, /*IsSBREL*/ true);732    }733    if (!constrainSelectedInstRegOperands(*OffsetMIB, TII, TRI, RBI))734      return false;735 736    // Add the offset to the SB register.737    MIB->setDesc(TII.get(Opcodes.ADDrr));738    MIB->removeOperand(1);739    MIB.addReg(ARM::R9) // FIXME: don't hardcode R9740        .addReg(Offset)741        .add(predOps(ARMCC::AL))742        .add(condCodeOp());743 744    return constrainSelectedInstRegOperands(*MIB, TII, TRI, RBI);745  }746 747  if (STI.isTargetELF()) {748    if (UseMovt) {749      MIB->setDesc(TII.get(Opcodes.MOVi32imm));750    } else {751      // Load the global's address from the constant pool.752      MIB->setDesc(TII.get(Opcodes.ConstPoolLoad));753      MIB->removeOperand(1);754      addOpsForConstantPoolLoad(MIB, GV, /*IsSBREL*/ false);755    }756  } else if (STI.isTargetMachO()) {757    if (UseMovt)758      MIB->setDesc(TII.get(Opcodes.MOVi32imm));759    else760      MIB->setDesc(TII.get(Opcodes.LDRLIT_ga_abs));761  } else {762    LLVM_DEBUG(dbgs() << "Object format not supported yet\n");763    return false;764  }765 766  return constrainSelectedInstRegOperands(*MIB, TII, TRI, RBI);767}768 769bool ARMInstructionSelector::selectSelect(MachineInstrBuilder &MIB,770                                          MachineRegisterInfo &MRI) const {771  auto &MBB = *MIB->getParent();772  auto InsertBefore = std::next(MIB->getIterator());773  auto &DbgLoc = MIB->getDebugLoc();774 775  // Compare the condition to 1.776  auto CondReg = MIB.getReg(1);777  assert(validReg(MRI, CondReg, 1, ARM::GPRRegBankID) &&778         "Unsupported types for select operation");779  auto CmpI = BuildMI(MBB, InsertBefore, DbgLoc, TII.get(Opcodes.TSTri))780                  .addUse(CondReg)781                  .addImm(1)782                  .add(predOps(ARMCC::AL));783  if (!constrainSelectedInstRegOperands(*CmpI, TII, TRI, RBI))784    return false;785 786  // Move a value into the result register based on the result of the787  // comparison.788  auto ResReg = MIB.getReg(0);789  auto TrueReg = MIB.getReg(2);790  auto FalseReg = MIB.getReg(3);791  assert(validOpRegPair(MRI, ResReg, TrueReg, 32, ARM::GPRRegBankID) &&792         validOpRegPair(MRI, TrueReg, FalseReg, 32, ARM::GPRRegBankID) &&793         "Unsupported types for select operation");794  auto Mov1I = BuildMI(MBB, InsertBefore, DbgLoc, TII.get(Opcodes.MOVCCr))795                   .addDef(ResReg)796                   .addUse(TrueReg)797                   .addUse(FalseReg)798                   .add(predOps(ARMCC::EQ, ARM::CPSR));799  if (!constrainSelectedInstRegOperands(*Mov1I, TII, TRI, RBI))800    return false;801 802  MIB->eraseFromParent();803  return true;804}805 806bool ARMInstructionSelector::selectShift(unsigned ShiftOpc,807                                         MachineInstrBuilder &MIB) const {808  assert(!STI.isThumb() && "Unsupported subtarget");809  MIB->setDesc(TII.get(ARM::MOVsr));810  MIB.addImm(ShiftOpc);811  MIB.add(predOps(ARMCC::AL)).add(condCodeOp());812  return constrainSelectedInstRegOperands(*MIB, TII, TRI, RBI);813}814 815void ARMInstructionSelector::renderVFPF32Imm(816  MachineInstrBuilder &NewInstBuilder, const MachineInstr &OldInst,817  int OpIdx) const {818  assert(OldInst.getOpcode() == TargetOpcode::G_FCONSTANT &&819         OpIdx == -1 && "Expected G_FCONSTANT");820 821  APFloat FPImmValue = OldInst.getOperand(1).getFPImm()->getValueAPF();822  int FPImmEncoding = ARM_AM::getFP32Imm(FPImmValue);823  assert(FPImmEncoding != -1 && "Invalid immediate value");824 825  NewInstBuilder.addImm(FPImmEncoding);826}827 828void ARMInstructionSelector::renderVFPF64Imm(829  MachineInstrBuilder &NewInstBuilder, const MachineInstr &OldInst, int OpIdx) const {830  assert(OldInst.getOpcode() == TargetOpcode::G_FCONSTANT &&831         OpIdx == -1 && "Expected G_FCONSTANT");832 833  APFloat FPImmValue = OldInst.getOperand(1).getFPImm()->getValueAPF();834  int FPImmEncoding = ARM_AM::getFP64Imm(FPImmValue);835  assert(FPImmEncoding != -1 && "Invalid immediate value");836 837  NewInstBuilder.addImm(FPImmEncoding);838}839 840void ARMInstructionSelector::renderInvertedImm(MachineInstrBuilder &MIB,841                                               const MachineInstr &MI,842                                               int OpIdx) const {843  assert(MI.getOpcode() == TargetOpcode::G_CONSTANT && OpIdx == -1 &&844         "Expected G_CONSTANT");845  int64_t CVal = MI.getOperand(1).getCImm()->getSExtValue();846  MIB.addImm(~CVal);847}848 849bool ARMInstructionSelector::select(MachineInstr &I) {850  assert(I.getParent() && "Instruction should be in a basic block!");851  assert(I.getParent()->getParent() && "Instruction should be in a function!");852 853  auto &MBB = *I.getParent();854  auto &MF = *MBB.getParent();855  auto &MRI = MF.getRegInfo();856 857  if (!isPreISelGenericOpcode(I.getOpcode())) {858    if (I.isCopy())859      return selectCopy(I, TII, MRI, TRI, RBI);860 861    return true;862  }863 864  using namespace TargetOpcode;865 866  if (selectImpl(I, *CoverageInfo))867    return true;868 869  MachineInstrBuilder MIB{MF, I};870  bool isSExt = false;871 872  switch (I.getOpcode()) {873  case G_SEXT:874    isSExt = true;875    [[fallthrough]];876  case G_ZEXT: {877    assert(MRI.getType(I.getOperand(0).getReg()).getSizeInBits() <= 32 &&878           "Unsupported destination size for extension");879 880    LLT SrcTy = MRI.getType(I.getOperand(1).getReg());881    unsigned SrcSize = SrcTy.getSizeInBits();882    switch (SrcSize) {883    case 1: {884      // ZExt boils down to & 0x1; for SExt we also subtract that from 0885      I.setDesc(TII.get(Opcodes.AND));886      MIB.addImm(1).add(predOps(ARMCC::AL)).add(condCodeOp());887 888      if (isSExt) {889        Register SExtResult = I.getOperand(0).getReg();890 891        // Use a new virtual register for the result of the AND892        Register AndResult = MRI.createVirtualRegister(&ARM::GPRRegClass);893        I.getOperand(0).setReg(AndResult);894 895        auto InsertBefore = std::next(I.getIterator());896        auto SubI =897            BuildMI(MBB, InsertBefore, I.getDebugLoc(), TII.get(Opcodes.RSB))898                .addDef(SExtResult)899                .addUse(AndResult)900                .addImm(0)901                .add(predOps(ARMCC::AL))902                .add(condCodeOp());903        if (!constrainSelectedInstRegOperands(*SubI, TII, TRI, RBI))904          return false;905      }906      break;907    }908    case 8:909    case 16: {910      unsigned NewOpc = selectSimpleExtOpc(I.getOpcode(), SrcSize);911      if (NewOpc == I.getOpcode())912        return false;913      I.setDesc(TII.get(NewOpc));914      MIB.addImm(0).add(predOps(ARMCC::AL));915      break;916    }917    default:918      LLVM_DEBUG(dbgs() << "Unsupported source size for extension");919      return false;920    }921    break;922  }923  case G_ANYEXT:924  case G_TRUNC: {925    // The high bits are undefined, so there's nothing special to do, just926    // treat it as a copy.927    auto SrcReg = I.getOperand(1).getReg();928    auto DstReg = I.getOperand(0).getReg();929 930    const auto &SrcRegBank = *RBI.getRegBank(SrcReg, MRI, TRI);931    const auto &DstRegBank = *RBI.getRegBank(DstReg, MRI, TRI);932 933    if (SrcRegBank.getID() == ARM::FPRRegBankID) {934      // This should only happen in the obscure case where we have put a 64-bit935      // integer into a D register. Get it out of there and keep only the936      // interesting part.937      assert(I.getOpcode() == G_TRUNC && "Unsupported operand for G_ANYEXT");938      assert(DstRegBank.getID() == ARM::GPRRegBankID &&939             "Unsupported combination of register banks");940      assert(MRI.getType(SrcReg).getSizeInBits() == 64 && "Unsupported size");941      assert(MRI.getType(DstReg).getSizeInBits() <= 32 && "Unsupported size");942 943      Register IgnoredBits = MRI.createVirtualRegister(&ARM::GPRRegClass);944      auto InsertBefore = std::next(I.getIterator());945      auto MovI =946          BuildMI(MBB, InsertBefore, I.getDebugLoc(), TII.get(ARM::VMOVRRD))947              .addDef(DstReg)948              .addDef(IgnoredBits)949              .addUse(SrcReg)950              .add(predOps(ARMCC::AL));951      if (!constrainSelectedInstRegOperands(*MovI, TII, TRI, RBI))952        return false;953 954      MIB->eraseFromParent();955      return true;956    }957 958    if (SrcRegBank.getID() != DstRegBank.getID()) {959      LLVM_DEBUG(960          dbgs() << "G_TRUNC/G_ANYEXT operands on different register banks\n");961      return false;962    }963 964    if (SrcRegBank.getID() != ARM::GPRRegBankID) {965      LLVM_DEBUG(dbgs() << "G_TRUNC/G_ANYEXT on non-GPR not supported yet\n");966      return false;967    }968 969    I.setDesc(TII.get(COPY));970    return selectCopy(I, TII, MRI, TRI, RBI);971  }972  case G_CONSTANT: {973    if (!MRI.getType(I.getOperand(0).getReg()).isPointer()) {974      // Non-pointer constants should be handled by TableGen.975      LLVM_DEBUG(dbgs() << "Unsupported constant type\n");976      return false;977    }978 979    auto &Val = I.getOperand(1);980    if (Val.isCImm()) {981      if (!Val.getCImm()->isZero()) {982        LLVM_DEBUG(dbgs() << "Unsupported pointer constant value\n");983        return false;984      }985      Val.ChangeToImmediate(0);986    } else {987      assert(Val.isImm() && "Unexpected operand for G_CONSTANT");988      if (Val.getImm() != 0) {989        LLVM_DEBUG(dbgs() << "Unsupported pointer constant value\n");990        return false;991      }992    }993 994    assert(!STI.isThumb() && "Unsupported subtarget");995    I.setDesc(TII.get(ARM::MOVi));996    MIB.add(predOps(ARMCC::AL)).add(condCodeOp());997    break;998  }999  case G_FCONSTANT: {1000    // Load from constant pool1001    unsigned Size = MRI.getType(I.getOperand(0).getReg()).getSizeInBits() / 8;1002    Align Alignment(Size);1003 1004    assert((Size == 4 || Size == 8) && "Unsupported FP constant type");1005    auto LoadOpcode = Size == 4 ? ARM::VLDRS : ARM::VLDRD;1006 1007    auto ConstPool = MF.getConstantPool();1008    auto CPIndex =1009        ConstPool->getConstantPoolIndex(I.getOperand(1).getFPImm(), Alignment);1010    MIB->setDesc(TII.get(LoadOpcode));1011    MIB->removeOperand(1);1012    MIB.addConstantPoolIndex(CPIndex, /*Offset*/ 0, /*TargetFlags*/ 0)1013        .addMemOperand(1014            MF.getMachineMemOperand(MachinePointerInfo::getConstantPool(MF),1015                                    MachineMemOperand::MOLoad, Size, Alignment))1016        .addImm(0)1017        .add(predOps(ARMCC::AL));1018    break;1019  }1020  case G_INTTOPTR:1021  case G_PTRTOINT: {1022    auto SrcReg = I.getOperand(1).getReg();1023    auto DstReg = I.getOperand(0).getReg();1024 1025    const auto &SrcRegBank = *RBI.getRegBank(SrcReg, MRI, TRI);1026    const auto &DstRegBank = *RBI.getRegBank(DstReg, MRI, TRI);1027 1028    if (SrcRegBank.getID() != DstRegBank.getID()) {1029      LLVM_DEBUG(1030          dbgs()1031          << "G_INTTOPTR/G_PTRTOINT operands on different register banks\n");1032      return false;1033    }1034 1035    if (SrcRegBank.getID() != ARM::GPRRegBankID) {1036      LLVM_DEBUG(1037          dbgs() << "G_INTTOPTR/G_PTRTOINT on non-GPR not supported yet\n");1038      return false;1039    }1040 1041    I.setDesc(TII.get(COPY));1042    return selectCopy(I, TII, MRI, TRI, RBI);1043  }1044  case G_SELECT:1045    return selectSelect(MIB, MRI);1046  case G_ICMP: {1047    CmpConstants Helper(Opcodes.CMPrr, ARM::INSTRUCTION_LIST_END,1048                        Opcodes.MOVCCi, ARM::GPRRegBankID, 32);1049    return selectCmp(Helper, MIB, MRI);1050  }1051  case G_FCMP: {1052    assert(STI.hasVFP2Base() && "Can't select fcmp without VFP");1053 1054    Register OpReg = I.getOperand(2).getReg();1055    unsigned Size = MRI.getType(OpReg).getSizeInBits();1056 1057    if (Size == 64 && !STI.hasFP64()) {1058      LLVM_DEBUG(dbgs() << "Subtarget only supports single precision");1059      return false;1060    }1061    if (Size != 32 && Size != 64) {1062      LLVM_DEBUG(dbgs() << "Unsupported size for G_FCMP operand");1063      return false;1064    }1065 1066    CmpConstants Helper(Size == 32 ? ARM::VCMPS : ARM::VCMPD, ARM::FMSTAT,1067                        Opcodes.MOVCCi, ARM::FPRRegBankID, Size);1068    return selectCmp(Helper, MIB, MRI);1069  }1070  case G_LSHR:1071    return selectShift(ARM_AM::ShiftOpc::lsr, MIB);1072  case G_ASHR:1073    return selectShift(ARM_AM::ShiftOpc::asr, MIB);1074  case G_SHL: {1075    return selectShift(ARM_AM::ShiftOpc::lsl, MIB);1076  }1077  case G_PTR_ADD:1078    I.setDesc(TII.get(Opcodes.ADDrr));1079    MIB.add(predOps(ARMCC::AL)).add(condCodeOp());1080    break;1081  case G_FRAME_INDEX:1082    // Add 0 to the given frame index and hope it will eventually be folded into1083    // the user(s).1084    I.setDesc(TII.get(Opcodes.ADDri));1085    MIB.addImm(0).add(predOps(ARMCC::AL)).add(condCodeOp());1086    break;1087  case G_GLOBAL_VALUE:1088    return selectGlobal(MIB, MRI);1089  case G_STORE:1090  case G_LOAD: {1091    auto &MemOp = **I.memoperands_begin();1092    if (MemOp.isAtomic()) {1093      LLVM_DEBUG(dbgs() << "Atomic load/store not supported yet\n");1094      return false;1095    }1096 1097    Register Reg = I.getOperand(0).getReg();1098    unsigned RegBank = RBI.getRegBank(Reg, MRI, TRI)->getID();1099 1100    LLT ValTy = MRI.getType(Reg);1101    const auto ValSize = ValTy.getSizeInBits();1102 1103    assert((ValSize != 64 || STI.hasVFP2Base()) &&1104           "Don't know how to load/store 64-bit value without VFP");1105 1106    if (auto *LoadMI = dyn_cast<GLoad>(&I)) {1107      Register PtrReg = LoadMI->getPointerReg();1108      MachineInstr *Ptr = MRI.getVRegDef(PtrReg);1109      if (Ptr->getOpcode() == TargetOpcode::G_CONSTANT_POOL) {1110        const MachineOperand &Index = Ptr->getOperand(1);1111        unsigned Opcode = Subtarget->isThumb() ? ARM::tLDRpci : ARM::LDRcp;1112 1113        auto Instr = BuildMI(MBB, I, I.getDebugLoc(), TII.get(Opcode))1114                         .addDef(Reg)1115                         .add(Index)1116                         .addImm(0)1117                         .add(predOps(ARMCC::AL))1118                         .addMemOperand(&MemOp);1119        if (!constrainSelectedInstRegOperands(*Instr, TII, TRI, RBI))1120          return false;1121        I.eraseFromParent();1122        return true;1123      }1124    }1125 1126    const auto NewOpc = selectLoadStoreOpCode(I.getOpcode(), RegBank, ValSize);1127    if (NewOpc == G_LOAD || NewOpc == G_STORE)1128      return false;1129 1130    I.setDesc(TII.get(NewOpc));1131 1132    if (NewOpc == ARM::LDRH || NewOpc == ARM::STRH)1133      // LDRH has a funny addressing mode (there's already a FIXME for it).1134      MIB.addReg(0);1135    MIB.addImm(0).add(predOps(ARMCC::AL));1136    break;1137  }1138  case G_MERGE_VALUES: {1139    if (!selectMergeValues(MIB, TII, MRI, TRI, RBI))1140      return false;1141    break;1142  }1143  case G_UNMERGE_VALUES: {1144    if (!selectUnmergeValues(MIB, TII, MRI, TRI, RBI))1145      return false;1146    break;1147  }1148  case G_BRCOND: {1149    if (!validReg(MRI, I.getOperand(0).getReg(), 1, ARM::GPRRegBankID)) {1150      LLVM_DEBUG(dbgs() << "Unsupported condition register for G_BRCOND");1151      return false;1152    }1153 1154    // Set the flags.1155    auto Test =1156        BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(Opcodes.TSTri))1157            .addReg(I.getOperand(0).getReg())1158            .addImm(1)1159            .add(predOps(ARMCC::AL));1160    if (!constrainSelectedInstRegOperands(*Test, TII, TRI, RBI))1161      return false;1162 1163    // Branch conditionally.1164    auto Branch =1165        BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(Opcodes.Bcc))1166            .add(I.getOperand(1))1167            .add(predOps(ARMCC::NE, ARM::CPSR));1168    if (!constrainSelectedInstRegOperands(*Branch, TII, TRI, RBI))1169      return false;1170    I.eraseFromParent();1171    return true;1172  }1173  case G_PHI: {1174    I.setDesc(TII.get(PHI));1175 1176    Register DstReg = I.getOperand(0).getReg();1177    const TargetRegisterClass *RC = guessRegClass(DstReg, MRI, TRI, RBI);1178    if (!RBI.constrainGenericRegister(DstReg, *RC, MRI)) {1179      break;1180    }1181 1182    return true;1183  }1184  default:1185    return false;1186  }1187 1188  return constrainSelectedInstRegOperands(I, TII, TRI, RBI);1189}1190