//===-- AMDGPURegBankLegalizeHelper.cpp -----------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
/// Implements actual lowering algorithms for each ID that can be used in
/// Rule.OperandMapping. Similar to legalizer helper but with register banks.
//
//===----------------------------------------------------------------------===//

#include "AMDGPURegBankLegalizeHelper.h"
#include "AMDGPUGlobalISelUtils.h"
#include "AMDGPUInstrInfo.h"
#include "AMDGPULaneMaskUtils.h"
#include "AMDGPURegBankLegalizeRules.h"
#include "AMDGPURegisterBankInfo.h"
#include "GCNSubtarget.h"
#include "MCTargetDesc/AMDGPUMCTargetDesc.h"
#include "llvm/CodeGen/GlobalISel/GenericMachineInstrs.h"
#include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineUniformityAnalysis.h"
#include "llvm/IR/IntrinsicsAMDGPU.h"

#define DEBUG_TYPE "amdgpu-regbanklegalize"

using namespace llvm;
using namespace AMDGPU;

RegBankLegalizeHelper::RegBankLegalizeHelper(
    MachineIRBuilder &B, const MachineUniformityInfo &MUI,
    const RegisterBankInfo &RBI, const RegBankLegalizeRules &RBLRules)
    : MF(B.getMF()), ST(MF.getSubtarget<GCNSubtarget>()), B(B),
      MRI(*B.getMRI()), MUI(MUI), RBI(RBI), MORE(MF, nullptr),
      RBLRules(RBLRules), IsWave32(ST.isWave32()),
      SgprRB(&RBI.getRegBank(AMDGPU::SGPRRegBankID)),
      VgprRB(&RBI.getRegBank(AMDGPU::VGPRRegBankID)),
      AgprRB(&RBI.getRegBank(AMDGPU::AGPRRegBankID)),
      VccRB(&RBI.getRegBank(AMDGPU::VCCRegBankID)) {}

bool RegBankLegalizeHelper::findRuleAndApplyMapping(MachineInstr &MI) {
  const SetOfRulesForOpcode *RuleSet = RBLRules.getRulesForOpc(MI);
  if (!RuleSet) {
    reportGISelFailure(MF, MORE, "amdgpu-regbanklegalize",
                       "No AMDGPU RegBankLegalize rules defined for opcode",
                       MI);
    return false;
  }

  const RegBankLLTMapping *Mapping = RuleSet->findMappingForMI(MI, MRI, MUI);
  if (!Mapping) {
    reportGISelFailure(MF, MORE, "amdgpu-regbanklegalize",
                       "AMDGPU RegBankLegalize: none of the rules defined with "
                       "'Any' for MI's opcode matched MI",
                       MI);
    return false;
  }

  WaterfallInfo WFI;
  unsigned OpIdx = 0;
  if (!Mapping->DstOpMapping.empty()) {
    B.setInsertPt(*MI.getParent(), std::next(MI.getIterator()));
    if (!applyMappingDst(MI, OpIdx, Mapping->DstOpMapping))
      return false;
  }
  if (!Mapping->SrcOpMapping.empty()) {
    B.setInstr(MI);
    if (!applyMappingSrc(MI, OpIdx, Mapping->SrcOpMapping, WFI))
      return false;
  }

  if (!lower(MI, *Mapping, WFI))
    return false;

  return true;
}

bool RegBankLegalizeHelper::executeInWaterfallLoop(MachineIRBuilder &B,
                                                   const WaterfallInfo &WFI) {
  assert(WFI.Start.isValid() && WFI.End.isValid() &&
         "Waterfall range not initialized");

  // Track use registers which have already been expanded with a readfirstlane
  // sequence. This may have multiple uses if moving a sequence.
  DenseMap<Register, Register> WaterfalledRegMap;

  MachineBasicBlock &MBB = B.getMBB();
  MachineFunction &MF = B.getMF();

  MachineBasicBlock::iterator BeginIt = WFI.Start;
  MachineBasicBlock::iterator EndIt = WFI.End;

  const SIRegisterInfo *TRI = ST.getRegisterInfo();
  const TargetRegisterClass *WaveRC = TRI->getWaveMaskRegClass();
  const AMDGPU::LaneMaskConstants &LMC = AMDGPU::LaneMaskConstants::get(ST);

#ifndef NDEBUG
  const int OrigRangeSize = std::distance(BeginIt, EndIt);
#endif

  MachineRegisterInfo &MRI = *B.getMRI();
  Register SaveExecReg = MRI.createVirtualRegister(WaveRC);
  Register InitSaveExecReg = MRI.createVirtualRegister(WaveRC);

  // Don't bother using generic instructions/registers for the exec mask.
  B.buildInstr(TargetOpcode::IMPLICIT_DEF).addDef(InitSaveExecReg);

  Register SavedExec = MRI.createVirtualRegister(WaveRC);

  // To insert the loop we need to split the block. Move everything before
  // this point to a new block, and insert a new empty block before this
  // instruction.
  MachineBasicBlock *LoopBB = MF.CreateMachineBasicBlock();
  MachineBasicBlock *BodyBB = MF.CreateMachineBasicBlock();
  MachineBasicBlock *RestoreExecBB = MF.CreateMachineBasicBlock();
  MachineBasicBlock *RemainderBB = MF.CreateMachineBasicBlock();
  MachineFunction::iterator MBBI(MBB);
  ++MBBI;
  MF.insert(MBBI, LoopBB);
  MF.insert(MBBI, BodyBB);
  MF.insert(MBBI, RestoreExecBB);
  MF.insert(MBBI, RemainderBB);

  LoopBB->addSuccessor(BodyBB);
  BodyBB->addSuccessor(RestoreExecBB);
  BodyBB->addSuccessor(LoopBB);

  // Move the rest of the block into a new block.
  RemainderBB->transferSuccessorsAndUpdatePHIs(&MBB);
  RemainderBB->splice(RemainderBB->begin(), &MBB, EndIt, MBB.end());

  MBB.addSuccessor(LoopBB);
  RestoreExecBB->addSuccessor(RemainderBB);

  B.setInsertPt(*LoopBB, LoopBB->end());

  // +-MBB:------------+
  // | ...             |
  // | %0 = G_INST_1   |
  // | %Dst = MI %Vgpr |
  // | %1 = G_INST_2   |
  // | ...             |
  // +-----------------+
  // ->
  // +-MBB-------------------------------+
  // | ...                               |
  // | %0 = G_INST_1                     |
  // | %SaveExecReg = S_MOV_B32 $exec_lo |
  // +----------------|------------------+
  //                  |                         /------------------------------|
  //                  V                        V                               |
  // +-LoopBB---------------------------------------------------------------+  |
  // | %CurrentLaneReg:sgpr(s32) = READFIRSTLANE %Vgpr                      |  |
  // |   instead of executing for each lane, see if other lanes had         |  |
  // |   same value for %Vgpr and execute for them also.                    |  |
  // | %CondReg:vcc(s1) = G_ICMP eq %CurrentLaneReg, %Vgpr                  |  |
  // | %CondRegLM:sreg_32 = ballot %CondReg // copy vcc to sreg32 lane mask |  |
  // | %SavedExec = S_AND_SAVEEXEC_B32 %CondRegLM                           |  |
  // |   exec is active for lanes with the same "CurrentLane value" in Vgpr |  |
  // +----------------|-----------------------------------------------------+  |
  //                  V                                                        |
  // +-BodyBB------------------------------------------------------------+     |
  // | %Dst = MI %CurrentLaneReg:sgpr(s32)                               |     |
  // |   executed only for active lanes and written to Dst               |     |
  // | $exec = S_XOR_B32 $exec, %SavedExec                               |     |
  // |   set active lanes to 0 in SavedExec, lanes that did not write to |     |
  // |   Dst yet, and set this as new exec (for READFIRSTLANE and ICMP)  |     |
  // | SI_WATERFALL_LOOP LoopBB                                          |-----|
  // +----------------|--------------------------------------------------+
  //                  V
  // +-RestoreExecBB--------------------------+
  // | $exec_lo = S_MOV_B32_term %SaveExecReg |
  // +----------------|-----------------------+
  //                  V
  // +-RemainderBB:----------------------+
  // | %1 = G_INST_2                     |
  // | ...                               |
  // +---------------------------------- +

  // Move the instruction into the loop body. Note we moved everything after
  // Range.end() already into a new block, so Range.end() is no longer valid.
  BodyBB->splice(BodyBB->end(), &MBB, BeginIt, MBB.end());

  // Figure out the iterator range after splicing the instructions.
  MachineBasicBlock::iterator NewBegin = BeginIt;
  auto NewEnd = BodyBB->end();
  assert(std::distance(NewBegin, NewEnd) == OrigRangeSize);

  B.setMBB(*LoopBB);
  Register CondReg;

  for (MachineInstr &MI : make_range(NewBegin, NewEnd)) {
    for (MachineOperand &Op : MI.all_uses()) {
      Register OldReg = Op.getReg();
      if (!WFI.SgprWaterfallOperandRegs.count(OldReg))
        continue;

      // See if we already processed this register in another instruction in
      // the sequence.
      auto OldVal = WaterfalledRegMap.find(OldReg);
      if (OldVal != WaterfalledRegMap.end()) {
        Op.setReg(OldVal->second);
        continue;
      }

      Register OpReg = Op.getReg();
      LLT OpTy = MRI.getType(OpReg);

      // TODO: support for agpr
      assert(MRI.getRegBank(OpReg) == VgprRB);
      Register CurrentLaneReg = MRI.createVirtualRegister({SgprRB, OpTy});
      buildReadFirstLane(B, CurrentLaneReg, OpReg, RBI);

      // Build the comparison(s), CurrentLaneReg == OpReg.
      unsigned OpSize = OpTy.getSizeInBits();
      unsigned PartSize = (OpSize % 64 == 0) ? 64 : 32;
      LLT PartTy = LLT::scalar(PartSize);
      unsigned NumParts = OpSize / PartSize;
      SmallVector<Register, 8> OpParts;
      SmallVector<Register, 8> CurrentLaneParts;

      if (NumParts == 1) {
        OpParts.push_back(OpReg);
        CurrentLaneParts.push_back(CurrentLaneReg);
      } else {
        auto UnmergeOp = B.buildUnmerge({VgprRB, PartTy}, OpReg);
        auto UnmergeCurrLane = B.buildUnmerge({SgprRB, PartTy}, CurrentLaneReg);
        for (unsigned i = 0; i < NumParts; ++i) {
          OpParts.push_back(UnmergeOp.getReg(i));
          CurrentLaneParts.push_back(UnmergeCurrLane.getReg(i));
        }
      }

      for (unsigned i = 0; i < NumParts; ++i) {
        Register CmpReg = MRI.createVirtualRegister(VccRB_S1);
        B.buildICmp(CmpInst::ICMP_EQ, CmpReg, CurrentLaneParts[i], OpParts[i]);

        if (!CondReg)
          CondReg = CmpReg;
        else
          CondReg = B.buildAnd(VccRB_S1, CondReg, CmpReg).getReg(0);
      }

      Op.setReg(CurrentLaneReg);

      // Make sure we don't re-process this register again.
      WaterfalledRegMap.insert(std::pair(OldReg, Op.getReg()));
    }
  }

  // Copy vcc to sgpr32/64, ballot becomes a no-op during instruction selection.
  Register CondRegLM =
      MRI.createVirtualRegister({WaveRC, LLT::scalar(IsWave32 ? 32 : 64)});
  B.buildIntrinsic(Intrinsic::amdgcn_ballot, CondRegLM).addReg(CondReg);

  // Update EXEC, save the original EXEC value to SavedExec.
  B.buildInstr(LMC.AndSaveExecOpc)
      .addDef(SavedExec)
      .addReg(CondRegLM, RegState::Kill);
  MRI.setSimpleHint(SavedExec, CondRegLM);

  B.setInsertPt(*BodyBB, BodyBB->end());

  // Update EXEC, switch all done bits to 0 and all todo bits to 1.
  B.buildInstr(LMC.XorTermOpc)
      .addDef(LMC.ExecReg)
      .addReg(LMC.ExecReg)
      .addReg(SavedExec);

  // XXX - s_xor_b64 sets scc to 1 if the result is nonzero, so can we use
  // s_cbranch_scc0?

  // Loop back to V_READFIRSTLANE_B32 if there are still variants to cover.
  B.buildInstr(AMDGPU::SI_WATERFALL_LOOP).addMBB(LoopBB);

  // Save the EXEC mask before the loop.
  B.setInsertPt(MBB, MBB.end());
  B.buildInstr(LMC.MovOpc).addDef(SaveExecReg).addReg(LMC.ExecReg);

  // Restore the EXEC mask after the loop.
  B.setInsertPt(*RestoreExecBB, RestoreExecBB->begin());
  B.buildInstr(LMC.MovTermOpc).addDef(LMC.ExecReg).addReg(SaveExecReg);

  // Set the insert point after the original instruction, so any new
  // instructions will be in the remainder.
  B.setInsertPt(*RemainderBB, RemainderBB->begin());

  return true;
}

bool RegBankLegalizeHelper::splitLoad(MachineInstr &MI,
                                      ArrayRef<LLT> LLTBreakdown, LLT MergeTy) {
  MachineFunction &MF = B.getMF();
  assert(MI.getNumMemOperands() == 1);
  MachineMemOperand &BaseMMO = **MI.memoperands_begin();
  Register Dst = MI.getOperand(0).getReg();
  const RegisterBank *DstRB = MRI.getRegBankOrNull(Dst);
  Register Base = MI.getOperand(1).getReg();
  LLT PtrTy = MRI.getType(Base);
  const RegisterBank *PtrRB = MRI.getRegBankOrNull(Base);
  LLT OffsetTy = LLT::scalar(PtrTy.getSizeInBits());
  SmallVector<Register, 4> LoadPartRegs;

  unsigned ByteOffset = 0;
  for (LLT PartTy : LLTBreakdown) {
    Register BasePlusOffset;
    if (ByteOffset == 0) {
      BasePlusOffset = Base;
    } else {
      auto Offset = B.buildConstant({PtrRB, OffsetTy}, ByteOffset);
      BasePlusOffset =
          B.buildObjectPtrOffset({PtrRB, PtrTy}, Base, Offset).getReg(0);
    }
    auto *OffsetMMO = MF.getMachineMemOperand(&BaseMMO, ByteOffset, PartTy);
    auto LoadPart = B.buildLoad({DstRB, PartTy}, BasePlusOffset, *OffsetMMO);
    LoadPartRegs.push_back(LoadPart.getReg(0));
    ByteOffset += PartTy.getSizeInBytes();
  }

  if (!MergeTy.isValid()) {
    // Loads are of same size, concat or merge them together.
    B.buildMergeLikeInstr(Dst, LoadPartRegs);
  } else {
    // Loads are not all of same size, need to unmerge them to smaller pieces
    // of MergeTy type, then merge pieces to Dst.
    SmallVector<Register, 4> MergeTyParts;
    for (Register Reg : LoadPartRegs) {
      if (MRI.getType(Reg) == MergeTy) {
        MergeTyParts.push_back(Reg);
      } else {
        auto Unmerge = B.buildUnmerge({DstRB, MergeTy}, Reg);
        for (unsigned i = 0; i < Unmerge->getNumOperands() - 1; ++i)
          MergeTyParts.push_back(Unmerge.getReg(i));
      }
    }
    B.buildMergeLikeInstr(Dst, MergeTyParts);
  }
  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::widenLoad(MachineInstr &MI, LLT WideTy,
                                      LLT MergeTy) {
  MachineFunction &MF = B.getMF();
  assert(MI.getNumMemOperands() == 1);
  MachineMemOperand &BaseMMO = **MI.memoperands_begin();
  Register Dst = MI.getOperand(0).getReg();
  const RegisterBank *DstRB = MRI.getRegBankOrNull(Dst);
  Register Base = MI.getOperand(1).getReg();

  MachineMemOperand *WideMMO = MF.getMachineMemOperand(&BaseMMO, 0, WideTy);
  auto WideLoad = B.buildLoad({DstRB, WideTy}, Base, *WideMMO);

  if (WideTy.isScalar()) {
    B.buildTrunc(Dst, WideLoad);
  } else {
    SmallVector<Register, 4> MergeTyParts;
    auto Unmerge = B.buildUnmerge({DstRB, MergeTy}, WideLoad);

    LLT DstTy = MRI.getType(Dst);
    unsigned NumElts = DstTy.getSizeInBits() / MergeTy.getSizeInBits();
    for (unsigned i = 0; i < NumElts; ++i) {
      MergeTyParts.push_back(Unmerge.getReg(i));
    }
    B.buildMergeLikeInstr(Dst, MergeTyParts);
  }
  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::widenMMOToS32(GAnyLoad &MI) const {
  Register Dst = MI.getDstReg();
  Register Ptr = MI.getPointerReg();
  MachineMemOperand &MMO = MI.getMMO();
  unsigned MemSize = 8 * MMO.getSize().getValue();

  MachineMemOperand *WideMMO = B.getMF().getMachineMemOperand(&MMO, 0, S32);

  if (MI.getOpcode() == G_LOAD) {
    B.buildLoad(Dst, Ptr, *WideMMO);
  } else {
    auto Load = B.buildLoad(SgprRB_S32, Ptr, *WideMMO);

    if (MI.getOpcode() == G_ZEXTLOAD) {
      APInt Mask = APInt::getLowBitsSet(S32.getSizeInBits(), MemSize);
      auto MaskCst = B.buildConstant(SgprRB_S32, Mask);
      B.buildAnd(Dst, Load, MaskCst);
    } else {
      assert(MI.getOpcode() == G_SEXTLOAD);
      B.buildSExtInReg(Dst, Load, MemSize);
    }
  }

  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerVccExtToSel(MachineInstr &MI) {
  Register Dst = MI.getOperand(0).getReg();
  LLT Ty = MRI.getType(Dst);
  Register Src = MI.getOperand(1).getReg();
  unsigned Opc = MI.getOpcode();
  int TrueExtCst = Opc == G_SEXT ? -1 : 1;
  if (Ty == S32 || Ty == S16) {
    auto True = B.buildConstant({VgprRB, Ty}, TrueExtCst);
    auto False = B.buildConstant({VgprRB, Ty}, 0);
    B.buildSelect(Dst, Src, True, False);
  } else if (Ty == S64) {
    auto True = B.buildConstant({VgprRB_S32}, TrueExtCst);
    auto False = B.buildConstant({VgprRB_S32}, 0);
    auto Lo = B.buildSelect({VgprRB_S32}, Src, True, False);
    MachineInstrBuilder Hi;
    switch (Opc) {
    case G_SEXT:
      Hi = Lo;
      break;
    case G_ZEXT:
      Hi = False;
      break;
    case G_ANYEXT:
      Hi = B.buildUndef({VgprRB_S32});
      break;
    default:
      reportGISelFailure(
          MF, MORE, "amdgpu-regbanklegalize",
          "AMDGPU RegBankLegalize: lowerVccExtToSel, Opcode not supported", MI);
      return false;
    }

    B.buildMergeValues(Dst, {Lo.getReg(0), Hi.getReg(0)});
  } else {
    reportGISelFailure(
        MF, MORE, "amdgpu-regbanklegalize",
        "AMDGPU RegBankLegalize: lowerVccExtToSel, Type not supported", MI);
    return false;
  }

  MI.eraseFromParent();
  return true;
}

std::pair<Register, Register> RegBankLegalizeHelper::unpackZExt(Register Reg) {
  auto PackedS32 = B.buildBitcast(SgprRB_S32, Reg);
  auto Mask = B.buildConstant(SgprRB_S32, 0x0000ffff);
  auto Lo = B.buildAnd(SgprRB_S32, PackedS32, Mask);
  auto Hi = B.buildLShr(SgprRB_S32, PackedS32, B.buildConstant(SgprRB_S32, 16));
  return {Lo.getReg(0), Hi.getReg(0)};
}

std::pair<Register, Register> RegBankLegalizeHelper::unpackSExt(Register Reg) {
  auto PackedS32 = B.buildBitcast(SgprRB_S32, Reg);
  auto Lo = B.buildSExtInReg(SgprRB_S32, PackedS32, 16);
  auto Hi = B.buildAShr(SgprRB_S32, PackedS32, B.buildConstant(SgprRB_S32, 16));
  return {Lo.getReg(0), Hi.getReg(0)};
}

std::pair<Register, Register> RegBankLegalizeHelper::unpackAExt(Register Reg) {
  auto PackedS32 = B.buildBitcast(SgprRB_S32, Reg);
  auto Lo = PackedS32;
  auto Hi = B.buildLShr(SgprRB_S32, PackedS32, B.buildConstant(SgprRB_S32, 16));
  return {Lo.getReg(0), Hi.getReg(0)};
}

std::pair<Register, Register>
RegBankLegalizeHelper::unpackAExtTruncS16(Register Reg) {
  auto [Lo32, Hi32] = unpackAExt(Reg);
  return {B.buildTrunc(SgprRB_S16, Lo32).getReg(0),
          B.buildTrunc(SgprRB_S16, Hi32).getReg(0)};
}

bool RegBankLegalizeHelper::lowerUnpackBitShift(MachineInstr &MI) {
  Register Lo, Hi;
  switch (MI.getOpcode()) {
  case AMDGPU::G_SHL: {
    auto [Val0, Val1] = unpackAExt(MI.getOperand(1).getReg());
    auto [Amt0, Amt1] = unpackAExt(MI.getOperand(2).getReg());
    Lo = B.buildInstr(MI.getOpcode(), {SgprRB_S32}, {Val0, Amt0}).getReg(0);
    Hi = B.buildInstr(MI.getOpcode(), {SgprRB_S32}, {Val1, Amt1}).getReg(0);
    break;
  }
  case AMDGPU::G_LSHR: {
    auto [Val0, Val1] = unpackZExt(MI.getOperand(1).getReg());
    auto [Amt0, Amt1] = unpackZExt(MI.getOperand(2).getReg());
    Lo = B.buildInstr(MI.getOpcode(), {SgprRB_S32}, {Val0, Amt0}).getReg(0);
    Hi = B.buildInstr(MI.getOpcode(), {SgprRB_S32}, {Val1, Amt1}).getReg(0);
    break;
  }
  case AMDGPU::G_ASHR: {
    auto [Val0, Val1] = unpackSExt(MI.getOperand(1).getReg());
    auto [Amt0, Amt1] = unpackSExt(MI.getOperand(2).getReg());
    Lo = B.buildAShr(SgprRB_S32, Val0, Amt0).getReg(0);
    Hi = B.buildAShr(SgprRB_S32, Val1, Amt1).getReg(0);
    break;
  }
  default:
    reportGISelFailure(
        MF, MORE, "amdgpu-regbanklegalize",
        "AMDGPU RegBankLegalize: lowerUnpackBitShift, case not implemented",
        MI);
    return false;
  }
  B.buildBuildVectorTrunc(MI.getOperand(0).getReg(), {Lo, Hi});
  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerUnpackMinMax(MachineInstr &MI) {
  Register Lo, Hi;
  switch (MI.getOpcode()) {
  case AMDGPU::G_SMIN:
  case AMDGPU::G_SMAX: {
    // For signed operations, use sign extension
    auto [Val0_Lo, Val0_Hi] = unpackSExt(MI.getOperand(1).getReg());
    auto [Val1_Lo, Val1_Hi] = unpackSExt(MI.getOperand(2).getReg());
    Lo = B.buildInstr(MI.getOpcode(), {SgprRB_S32}, {Val0_Lo, Val1_Lo})
             .getReg(0);
    Hi = B.buildInstr(MI.getOpcode(), {SgprRB_S32}, {Val0_Hi, Val1_Hi})
             .getReg(0);
    break;
  }
  case AMDGPU::G_UMIN:
  case AMDGPU::G_UMAX: {
    // For unsigned operations, use zero extension
    auto [Val0_Lo, Val0_Hi] = unpackZExt(MI.getOperand(1).getReg());
    auto [Val1_Lo, Val1_Hi] = unpackZExt(MI.getOperand(2).getReg());
    Lo = B.buildInstr(MI.getOpcode(), {SgprRB_S32}, {Val0_Lo, Val1_Lo})
             .getReg(0);
    Hi = B.buildInstr(MI.getOpcode(), {SgprRB_S32}, {Val0_Hi, Val1_Hi})
             .getReg(0);
    break;
  }
  default:
    reportGISelFailure(
        MF, MORE, "amdgpu-regbanklegalize",
        "AMDGPU RegBankLegalize: lowerUnpackMinMax, case not implemented", MI);
    return false;
  }
  B.buildBuildVectorTrunc(MI.getOperand(0).getReg(), {Lo, Hi});
  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerUnpackAExt(MachineInstr &MI) {
  auto [Op1Lo, Op1Hi] = unpackAExt(MI.getOperand(1).getReg());
  auto [Op2Lo, Op2Hi] = unpackAExt(MI.getOperand(2).getReg());
  auto ResLo = B.buildInstr(MI.getOpcode(), {SgprRB_S32}, {Op1Lo, Op2Lo});
  auto ResHi = B.buildInstr(MI.getOpcode(), {SgprRB_S32}, {Op1Hi, Op2Hi});
  B.buildBuildVectorTrunc(MI.getOperand(0).getReg(),
                          {ResLo.getReg(0), ResHi.getReg(0)});
  MI.eraseFromParent();
  return true;
}

static bool isSignedBFE(MachineInstr &MI) {
  if (GIntrinsic *GI = dyn_cast<GIntrinsic>(&MI))
    return (GI->is(Intrinsic::amdgcn_sbfe));

  return MI.getOpcode() == AMDGPU::G_SBFX;
}

bool RegBankLegalizeHelper::lowerV_BFE(MachineInstr &MI) {
  Register Dst = MI.getOperand(0).getReg();
  assert(MRI.getType(Dst) == LLT::scalar(64));
  bool Signed = isSignedBFE(MI);
  unsigned FirstOpnd = isa<GIntrinsic>(MI) ? 2 : 1;
  // Extract bitfield from Src, LSBit is the least-significant bit for the
  // extraction (field offset) and Width is size of bitfield.
  Register Src = MI.getOperand(FirstOpnd).getReg();
  Register LSBit = MI.getOperand(FirstOpnd + 1).getReg();
  Register Width = MI.getOperand(FirstOpnd + 2).getReg();
  // Comments are for signed bitfield extract, similar for unsigned. x is sign
  // bit. s is sign, l is LSB and y are remaining bits of bitfield to extract.

  // Src >> LSBit Hi|Lo: x?????syyyyyyl??? -> xxxx?????syyyyyyl
  unsigned SHROpc = Signed ? AMDGPU::G_ASHR : AMDGPU::G_LSHR;
  auto SHRSrc = B.buildInstr(SHROpc, {{VgprRB, S64}}, {Src, LSBit});

  auto ConstWidth = getIConstantVRegValWithLookThrough(Width, MRI);

  // Expand to Src >> LSBit << (64 - Width) >> (64 - Width)
  // << (64 - Width): Hi|Lo: xxxx?????syyyyyyl -> syyyyyyl000000000
  // >> (64 - Width): Hi|Lo: syyyyyyl000000000 -> ssssssssssyyyyyyl
  if (!ConstWidth) {
    auto Amt = B.buildSub(VgprRB_S32, B.buildConstant(SgprRB_S32, 64), Width);
    auto SignBit = B.buildShl({VgprRB, S64}, SHRSrc, Amt);
    B.buildInstr(SHROpc, {Dst}, {SignBit, Amt});
    MI.eraseFromParent();
    return true;
  }

  uint64_t WidthImm = ConstWidth->Value.getZExtValue();
  auto UnmergeSHRSrc = B.buildUnmerge(VgprRB_S32, SHRSrc);
  Register SHRSrcLo = UnmergeSHRSrc.getReg(0);
  Register SHRSrcHi = UnmergeSHRSrc.getReg(1);
  auto Zero = B.buildConstant({VgprRB, S32}, 0);
  unsigned BFXOpc = Signed ? AMDGPU::G_SBFX : AMDGPU::G_UBFX;

  if (WidthImm <= 32) {
    // SHRSrc Hi|Lo: ????????|???syyyl -> ????????|ssssyyyl
    auto Lo = B.buildInstr(BFXOpc, {VgprRB_S32}, {SHRSrcLo, Zero, Width});
    MachineInstrBuilder Hi;
    if (Signed) {
      // SHRSrc Hi|Lo: ????????|ssssyyyl -> ssssssss|ssssyyyl
      Hi = B.buildAShr(VgprRB_S32, Lo, B.buildConstant(VgprRB_S32, 31));
    } else {
      // SHRSrc Hi|Lo: ????????|000syyyl -> 00000000|000syyyl
      Hi = Zero;
    }
    B.buildMergeLikeInstr(Dst, {Lo, Hi});
  } else {
    auto Amt = B.buildConstant(VgprRB_S32, WidthImm - 32);
    // SHRSrc Hi|Lo: ??????sy|yyyyyyyl -> sssssssy|yyyyyyyl
    auto Hi = B.buildInstr(BFXOpc, {VgprRB_S32}, {SHRSrcHi, Zero, Amt});
    B.buildMergeLikeInstr(Dst, {SHRSrcLo, Hi});
  }

  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerS_BFE(MachineInstr &MI) {
  Register DstReg = MI.getOperand(0).getReg();
  LLT Ty = MRI.getType(DstReg);
  bool Signed = isSignedBFE(MI);
  unsigned FirstOpnd = isa<GIntrinsic>(MI) ? 2 : 1;
  Register Src = MI.getOperand(FirstOpnd).getReg();
  Register LSBit = MI.getOperand(FirstOpnd + 1).getReg();
  Register Width = MI.getOperand(FirstOpnd + 2).getReg();
  // For uniform bit field extract there are 4 available instructions, but
  // LSBit(field offset) and Width(size of bitfield) need to be packed in S32,
  // field offset in low and size in high 16 bits.

  // Src1 Hi16|Lo16 = Size|FieldOffset
  auto Mask = B.buildConstant(SgprRB_S32, maskTrailingOnes<unsigned>(6));
  auto FieldOffset = B.buildAnd(SgprRB_S32, LSBit, Mask);
  auto Size = B.buildShl(SgprRB_S32, Width, B.buildConstant(SgprRB_S32, 16));
  auto Src1 = B.buildOr(SgprRB_S32, FieldOffset, Size);
  unsigned Opc32 = Signed ? AMDGPU::S_BFE_I32 : AMDGPU::S_BFE_U32;
  unsigned Opc64 = Signed ? AMDGPU::S_BFE_I64 : AMDGPU::S_BFE_U64;
  unsigned Opc = Ty == S32 ? Opc32 : Opc64;

  // Select machine instruction, because of reg class constraining, insert
  // copies from reg class to reg bank.
  auto S_BFE = B.buildInstr(Opc, {{SgprRB, Ty}},
                            {B.buildCopy(Ty, Src), B.buildCopy(S32, Src1)});
  constrainSelectedInstRegOperands(*S_BFE, *ST.getInstrInfo(),
                                   *ST.getRegisterInfo(), RBI);

  B.buildCopy(DstReg, S_BFE->getOperand(0).getReg());
  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerSplitTo32(MachineInstr &MI) {
  Register Dst = MI.getOperand(0).getReg();
  LLT DstTy = MRI.getType(Dst);
  assert(DstTy == V4S16 || DstTy == V2S32 || DstTy == S64);
  LLT Ty = DstTy == V4S16 ? V2S16 : S32;
  auto Op1 = B.buildUnmerge({VgprRB, Ty}, MI.getOperand(1).getReg());
  auto Op2 = B.buildUnmerge({VgprRB, Ty}, MI.getOperand(2).getReg());
  unsigned Opc = MI.getOpcode();
  auto Flags = MI.getFlags();
  auto Lo =
      B.buildInstr(Opc, {{VgprRB, Ty}}, {Op1.getReg(0), Op2.getReg(0)}, Flags);
  auto Hi =
      B.buildInstr(Opc, {{VgprRB, Ty}}, {Op1.getReg(1), Op2.getReg(1)}, Flags);
  B.buildMergeLikeInstr(Dst, {Lo, Hi});
  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerSplitTo32Mul(MachineInstr &MI) {
  Register Dst = MI.getOperand(0).getReg();
  assert(MRI.getType(Dst) == S64);
  auto Op1 = B.buildUnmerge({VgprRB_S32}, MI.getOperand(1).getReg());
  auto Op2 = B.buildUnmerge({VgprRB_S32}, MI.getOperand(2).getReg());

  // TODO: G_AMDGPU_MAD_* optimizations for G_MUL divergent S64 operation to
  // match GlobalISel with old regbankselect.
  auto Lo = B.buildMul(VgprRB_S32, Op1.getReg(0), Op2.getReg(0));
  auto Carry = B.buildUMulH(VgprRB_S32, Op1.getReg(0), Op2.getReg(0));
  auto MulLo0Hi1 = B.buildMul(VgprRB_S32, Op1.getReg(0), Op2.getReg(1));
  auto MulHi0Lo1 = B.buildMul(VgprRB_S32, Op1.getReg(1), Op2.getReg(0));
  auto Sum = B.buildAdd(VgprRB_S32, MulLo0Hi1, MulHi0Lo1);
  auto Hi = B.buildAdd(VgprRB_S32, Sum, Carry);

  B.buildMergeLikeInstr(Dst, {Lo, Hi});
  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerSplitTo16(MachineInstr &MI) {
  Register Dst = MI.getOperand(0).getReg();
  assert(MRI.getType(Dst) == V2S16);
  unsigned Opc = MI.getOpcode();
  unsigned NumOps = MI.getNumOperands();
  auto Flags = MI.getFlags();

  auto [Op1Lo, Op1Hi] = unpackAExtTruncS16(MI.getOperand(1).getReg());

  if (NumOps == 2) {
    auto Lo = B.buildInstr(Opc, {SgprRB_S16}, {Op1Lo}, Flags);
    auto Hi = B.buildInstr(Opc, {SgprRB_S16}, {Op1Hi}, Flags);
    B.buildMergeLikeInstr(Dst, {Lo, Hi});
    MI.eraseFromParent();
    return true;
  }

  auto [Op2Lo, Op2Hi] = unpackAExtTruncS16(MI.getOperand(2).getReg());

  if (NumOps == 3) {
    auto Lo = B.buildInstr(Opc, {SgprRB_S16}, {Op1Lo, Op2Lo}, Flags);
    auto Hi = B.buildInstr(Opc, {SgprRB_S16}, {Op1Hi, Op2Hi}, Flags);
    B.buildMergeLikeInstr(Dst, {Lo, Hi});
    MI.eraseFromParent();
    return true;
  }

  assert(NumOps == 4);
  auto [Op3Lo, Op3Hi] = unpackAExtTruncS16(MI.getOperand(3).getReg());
  auto Lo = B.buildInstr(Opc, {SgprRB_S16}, {Op1Lo, Op2Lo, Op3Lo}, Flags);
  auto Hi = B.buildInstr(Opc, {SgprRB_S16}, {Op1Hi, Op2Hi, Op3Hi}, Flags);
  B.buildMergeLikeInstr(Dst, {Lo, Hi});
  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerUniMAD64(MachineInstr &MI) {
  Register Dst0 = MI.getOperand(0).getReg();
  Register Dst1 = MI.getOperand(1).getReg();
  Register Src0 = MI.getOperand(2).getReg();
  Register Src1 = MI.getOperand(3).getReg();
  Register Src2 = MI.getOperand(4).getReg();

  const GCNSubtarget &ST = B.getMF().getSubtarget<GCNSubtarget>();

  // Keep the multiplication on the SALU.
  Register DstLo = B.buildMul(SgprRB_S32, Src0, Src1).getReg(0);
  Register DstHi = MRI.createVirtualRegister(SgprRB_S32);
  if (ST.hasScalarMulHiInsts()) {
    B.buildInstr(AMDGPU::G_UMULH, {{DstHi}}, {Src0, Src1});
  } else {
    auto VSrc0 = B.buildCopy(VgprRB_S32, Src0);
    auto VSrc1 = B.buildCopy(VgprRB_S32, Src1);
    auto MulHi = B.buildInstr(AMDGPU::G_UMULH, {VgprRB_S32}, {VSrc0, VSrc1});
    buildReadAnyLane(B, DstHi, MulHi.getReg(0), RBI);
  }

  // Accumulate and produce the "carry-out" bit.

  // The "carry-out" is defined as bit 64 of the result when computed as a
  // big integer. For unsigned multiply-add, this matches the usual
  // definition of carry-out.
  if (mi_match(Src2, MRI, MIPatternMatch::m_ZeroInt())) {
    // No accumulate: result is just the multiplication, carry is 0.
    B.buildMergeLikeInstr(Dst0, {DstLo, DstHi});
    B.buildConstant(Dst1, 0);
  } else {
    // Accumulate: add Src2 to the multiplication result with carry chain.
    Register Src2Lo = MRI.createVirtualRegister(SgprRB_S32);
    Register Src2Hi = MRI.createVirtualRegister(SgprRB_S32);
    B.buildUnmerge({Src2Lo, Src2Hi}, Src2);

    auto AddLo = B.buildUAddo(SgprRB_S32, SgprRB_S32, DstLo, Src2Lo);
    auto AddHi =
        B.buildUAdde(SgprRB_S32, SgprRB_S32, DstHi, Src2Hi, AddLo.getReg(1));
    B.buildMergeLikeInstr(Dst0, {AddLo.getReg(0), AddHi.getReg(0)});
    B.buildCopy(Dst1, AddHi.getReg(1));
  }

  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerSplitTo32Select(MachineInstr &MI) {
  Register Dst = MI.getOperand(0).getReg();
  LLT DstTy = MRI.getType(Dst);
  assert(DstTy == V4S16 || DstTy == V2S32 || DstTy == S64 ||
         (DstTy.isPointer() && DstTy.getSizeInBits() == 64));
  LLT Ty = DstTy == V4S16 ? V2S16 : S32;
  auto Op2 = B.buildUnmerge({VgprRB, Ty}, MI.getOperand(2).getReg());
  auto Op3 = B.buildUnmerge({VgprRB, Ty}, MI.getOperand(3).getReg());
  Register Cond = MI.getOperand(1).getReg();
  auto Flags = MI.getFlags();
  auto Lo =
      B.buildSelect({VgprRB, Ty}, Cond, Op2.getReg(0), Op3.getReg(0), Flags);
  auto Hi =
      B.buildSelect({VgprRB, Ty}, Cond, Op2.getReg(1), Op3.getReg(1), Flags);

  B.buildMergeLikeInstr(Dst, {Lo, Hi});
  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerSplitTo32SExtInReg(MachineInstr &MI) {
  auto Op1 = B.buildUnmerge(VgprRB_S32, MI.getOperand(1).getReg());
  int Amt = MI.getOperand(2).getImm();
  Register Lo, Hi;
  // Hi|Lo: s sign bit, ?/x bits changed/not changed by sign-extend
  if (Amt <= 32) {
    auto Freeze = B.buildFreeze(VgprRB_S32, Op1.getReg(0));
    if (Amt == 32) {
      // Hi|Lo: ????????|sxxxxxxx -> ssssssss|sxxxxxxx
      Lo = Freeze.getReg(0);
    } else {
      // Hi|Lo: ????????|???sxxxx -> ssssssss|ssssxxxx
      Lo = B.buildSExtInReg(VgprRB_S32, Freeze, Amt).getReg(0);
    }

    auto SignExtCst = B.buildConstant(SgprRB_S32, 31);
    Hi = B.buildAShr(VgprRB_S32, Lo, SignExtCst).getReg(0);
  } else {
    // Hi|Lo: ?????sxx|xxxxxxxx -> ssssssxx|xxxxxxxx
    Lo = Op1.getReg(0);
    Hi = B.buildSExtInReg(VgprRB_S32, Op1.getReg(1), Amt - 32).getReg(0);
  }

  B.buildMergeLikeInstr(MI.getOperand(0).getReg(), {Lo, Hi});
  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerSplitBitCount64To32(MachineInstr &MI) {
  // Split 64-bit find-first-bit operations into 32-bit halves:
  //   (ffbh hi:lo)            -> umin(ffbh(hi), uaddsat(ffbh(lo), 32))
  //   (ffbl hi:lo)            -> umin(ffbl(lo), uaddsat(ffbl(hi), 32))
  //   (ctlz_zero_undef hi:lo) -> umin(ffbh(hi), add(ffbh(lo), 32))
  //   (cttz_zero_undef hi:lo) -> umin(ffbl(lo), add(ffbl(hi), 32))
  unsigned Opc = MI.getOpcode();

  // FFBH/FFBL return 0xFFFFFFFF on zero input, using uaddsat to avoid
  // wrapping. CTLZ/CTTZ guarantee non-zero input (zero_undef), so plain add
  // is fine.
  unsigned FFBOpc;
  unsigned AddOpc;
  bool SearchFromMSB;
  switch (Opc) {
  case AMDGPU::G_AMDGPU_FFBH_U32:
    FFBOpc = Opc;
    AddOpc = AMDGPU::G_UADDSAT;
    SearchFromMSB = true;
    break;
  case AMDGPU::G_AMDGPU_FFBL_B32:
    FFBOpc = Opc;
    AddOpc = AMDGPU::G_UADDSAT;
    SearchFromMSB = false;
    break;
  case AMDGPU::G_CTLZ_ZERO_UNDEF:
    FFBOpc = AMDGPU::G_AMDGPU_FFBH_U32;
    AddOpc = AMDGPU::G_ADD;
    SearchFromMSB = true;
    break;
  case AMDGPU::G_CTTZ_ZERO_UNDEF:
    FFBOpc = AMDGPU::G_AMDGPU_FFBL_B32;
    AddOpc = AMDGPU::G_ADD;
    SearchFromMSB = false;
    break;
  default:
    llvm_unreachable("unexpected opcode in lowerSplitBitCount64To32");
  }

  auto Unmerge = B.buildUnmerge(VgprRB_S32, MI.getOperand(1).getReg());
  Register Lo = Unmerge.getReg(0);
  Register Hi = Unmerge.getReg(1);

  // MSB-first (FFBH/CTLZ) searches hi first; LSB-first (FFBL/CTTZ) searches
  // lo first. The secondary half adds 32 to account for the primary half's
  // width.
  auto Primary = B.buildInstr(FFBOpc, {VgprRB_S32}, {SearchFromMSB ? Hi : Lo});
  auto Secondary =
      B.buildInstr(FFBOpc, {VgprRB_S32}, {SearchFromMSB ? Lo : Hi});

  auto Adjusted = B.buildInstr(AddOpc, {VgprRB_S32},
                               {Secondary, B.buildConstant(VgprRB_S32, 32)});
  B.buildUMin(MI.getOperand(0).getReg(), Primary, Adjusted);

  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerExtrVecEltToSel(MachineInstr &MI) {
  // Lower extract vector element to a compare-select chain:
  //   result = elt[0]
  //   for i in 1..N-1:
  //     result = (idx == i) ? elt[i] : result
  //
  // When the index is divergent, each lane may want a different element, so
  // we must check every element per lane.
  Register Dst = MI.getOperand(0).getReg();
  Register Src = MI.getOperand(1).getReg();
  Register Idx = MI.getOperand(2).getReg();

  LLT VecTy = MRI.getType(Src);
  LLT ScalarTy = VecTy.getScalarType();
  unsigned NumElts = VecTy.getNumElements();
  MachineRegisterInfo::VRegAttrs VgprRB_EltTy = {VgprRB, ScalarTy};

  auto Unmerge = B.buildUnmerge(VgprRB_EltTy, Src);

  if (ScalarTy.getSizeInBits() == 32) {
    Register PrevSelect = Unmerge.getReg(0);
    for (unsigned I = 1; I < NumElts; ++I) {
      auto IdxConst = B.buildConstant({SgprRB, MRI.getType(Idx)}, I);
      auto Cmp = B.buildICmp(CmpInst::ICMP_EQ, VccRB_S1, Idx, IdxConst);
      PrevSelect =
          B.buildSelect(VgprRB_EltTy, Cmp, Unmerge.getReg(I), PrevSelect)
              .getReg(0);
    }
    B.buildCopy(Dst, PrevSelect);
  } else if (ScalarTy.getSizeInBits() == 64) {
    auto InitUnmerge = B.buildUnmerge(VgprRB_S32, Unmerge.getReg(0));
    Register PrevLo = InitUnmerge.getReg(0);
    Register PrevHi = InitUnmerge.getReg(1);
    for (unsigned I = 1; I < NumElts; ++I) {
      auto IdxConst = B.buildConstant({SgprRB, MRI.getType(Idx)}, I);
      auto Cmp = B.buildICmp(CmpInst::ICMP_EQ, VccRB_S1, Idx, IdxConst);
      auto EltUnmerge = B.buildUnmerge(VgprRB_S32, Unmerge.getReg(I));
      PrevLo = B.buildSelect(VgprRB_S32, Cmp, EltUnmerge.getReg(0), PrevLo)
                   .getReg(0);
      PrevHi = B.buildSelect(VgprRB_S32, Cmp, EltUnmerge.getReg(1), PrevHi)
                   .getReg(0);
    }
    B.buildMergeLikeInstr(Dst, {PrevLo, PrevHi});
  } else {
    reportGISelFailure(
        MF, MORE, "amdgpu-regbanklegalize",
        "AMDGPU RegBankLegalize: ExtrVecEltToSel unsupported element type", MI);
    return false;
  }

  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerExtrVecEltTo32(MachineInstr &MI) {
  // Reduce a 64-bit element extract to two 32-bit extracts:
  //   vec32 = bitcast <N x s64> to <2N x s32>
  //   lo = vec32[idx * 2]
  //   hi = vec32[idx * 2 + 1]
  //   result = merge(lo, hi)
  //
  // When the index is uniform, all lanes extract the same element, so we can
  // just split the s64 extract into two s32 extracts which lower to MOVREL.
  Register Dst = MI.getOperand(0).getReg();
  Register Src = MI.getOperand(1).getReg();
  Register Idx = MI.getOperand(2).getReg();

  LLT SrcTy = MRI.getType(Src);
  LLT Vec32Ty = LLT::fixed_vector(2 * SrcTy.getNumElements(), 32);

  assert(MRI.getRegBank(Src) == VgprRB && MRI.getRegBank(Idx) == SgprRB &&
         "expected VGPR src and SGPR idx");

  auto CastSrc = B.buildBitcast({VgprRB, Vec32Ty}, Src);

  // Calculate new Lo and Hi indices
  auto One = B.buildConstant(SgprRB_S32, 1);
  auto IdxLo = B.buildShl(SgprRB_S32, Idx, One);
  auto IdxHi = B.buildAdd(SgprRB_S32, IdxLo, One);

  auto ExtLo = B.buildExtractVectorElement(VgprRB_S32, CastSrc, IdxLo);
  auto ExtHi = B.buildExtractVectorElement(VgprRB_S32, CastSrc, IdxHi);

  B.buildMergeLikeInstr(Dst, {ExtLo.getReg(0), ExtHi.getReg(0)});

  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerInsVecEltToSel(MachineInstr &MI) {
  // Lower insert vector element to a compare-select chain:
  //   for i in 0..N-1:
  //     result[i] = (idx == i) ? elt : srcVec[i]
  //   dst = merge(result[0..N-1])
  //
  // VGPR B64 requires splitting to lo/hi s32 pairs since there is no
  // v_cndmask_b64. SGPR B64/B32 and VGPR B32 can be handled natively.
  Register Dst = MI.getOperand(0).getReg();
  Register Src = MI.getOperand(1).getReg();
  Register Elt = MI.getOperand(2).getReg();
  Register Idx = MI.getOperand(3).getReg();

  LLT VecTy = MRI.getType(Src);
  LLT ScalarTy = VecTy.getScalarType();
  unsigned NumElts = VecTy.getNumElements();
  const RegisterBank *SrcRB = MRI.getRegBank(Src);
  bool IsSGPR = (SrcRB == SgprRB);
  SmallVector<Register, 16> Selects;

  if (!IsSGPR && ScalarTy.getSizeInBits() == 64) {
    // VGPR B64: split to 32-bit lo/hi since there is no v_cndmask_b64.
    auto Unmerge = B.buildUnmerge(VgprRB_S32, Src);
    auto EltUnmerge = B.buildUnmerge(VgprRB_S32, Elt);
    Register EltLo = EltUnmerge.getReg(0);
    Register EltHi = EltUnmerge.getReg(1);
    for (unsigned I = 0; I < NumElts; ++I) {
      auto IdxConst = B.buildConstant(VgprRB_S32, I);
      auto Cmp = B.buildICmp(CmpInst::ICMP_EQ, VccRB_S1, Idx, IdxConst);
      Selects.push_back(
          B.buildSelect(VgprRB_S32, Cmp, EltLo, Unmerge.getReg(2 * I))
              .getReg(0));
      Selects.push_back(
          B.buildSelect(VgprRB_S32, Cmp, EltHi, Unmerge.getReg(2 * I + 1))
              .getReg(0));
    }
    LLT Vec32Ty = LLT::fixed_vector(2 * NumElts, 32);
    auto Vec32 = B.buildBuildVector({VgprRB, Vec32Ty}, Selects);
    B.buildBitcast(Dst, Vec32);
  } else if (ScalarTy.getSizeInBits() == 32 || ScalarTy.getSizeInBits() == 64) {
    // B32 (any bank) and SGPR B64: element-wise select at native width.
    MachineRegisterInfo::VRegAttrs SrcRB_EltTy = {SrcRB, ScalarTy};
    MachineRegisterInfo::VRegAttrs CmpTy = IsSGPR ? SgprRB_S32 : VccRB_S1;
    auto Unmerge = B.buildUnmerge(SrcRB_EltTy, Src);
    for (unsigned I = 0; I < NumElts; ++I) {
      auto IdxConst = B.buildConstant(SgprRB_S32, I);
      auto Cmp = B.buildICmp(CmpInst::ICMP_EQ, CmpTy, Idx, IdxConst);
      Selects.push_back(
          B.buildSelect(SrcRB_EltTy, Cmp, Elt, Unmerge.getReg(I)).getReg(0));
    }
    B.buildMergeLikeInstr(Dst, Selects);
  } else {
    reportGISelFailure(
        MF, MORE, "amdgpu-regbanklegalize",
        "AMDGPU RegBankLegalize: InsVecEltToSel unsupported element type", MI);
    return false;
  }

  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerInsVecEltTo32(MachineInstr &MI) {
  // Reduce a 64-bit element insert to two 32-bit inserts:
  //   vec32 = bitcast <N x s64> to <2N x s32>
  //   lo, hi = unmerge elt
  //   vec32[idx * 2] = lo
  //   vec32[idx * 2 + 1] = hi
  //   dst = bitcast <2N x s32> to <N x s64>
  //
  // When the index is uniform, all lanes insert at the same position, so we
  // can split the s64 insert into two s32 inserts which lower to MOVREL/GPRIDX.
  Register Dst = MI.getOperand(0).getReg();
  Register Src = MI.getOperand(1).getReg();
  Register Elt = MI.getOperand(2).getReg();
  Register Idx = MI.getOperand(3).getReg();

  LLT SrcTy = MRI.getType(Src);
  LLT Vec32Ty = LLT::fixed_vector(2 * SrcTy.getNumElements(), 32);

  assert(MRI.getRegBank(Src) == VgprRB && MRI.getRegBank(Idx) == SgprRB &&
         "expected VGPR src and SGPR idx");

  MachineRegisterInfo::VRegAttrs VgprRB_Vec32Ty = {VgprRB, Vec32Ty};

  auto CastSrc = B.buildBitcast(VgprRB_Vec32Ty, Src);
  auto EltUnmerge = B.buildUnmerge(VgprRB_S32, Elt);

  // Calculate new Lo and Hi indices
  auto One = B.buildConstant(SgprRB_S32, 1);
  auto IdxLo = B.buildShl(SgprRB_S32, Idx, One);
  auto IdxHi = B.buildAdd(SgprRB_S32, IdxLo, One);

  auto InsLo = B.buildInsertVectorElement(VgprRB_Vec32Ty, CastSrc,
                                          EltUnmerge.getReg(0), IdxLo);
  auto InsHi = B.buildInsertVectorElement(VgprRB_Vec32Ty, InsLo,
                                          EltUnmerge.getReg(1), IdxHi);

  B.buildBitcast(Dst, InsHi);

  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerAbsToNegMax(MachineInstr &MI) {
  // Lower divergent G_ABS to smax(x, 0 - x) in the VGPR bank:
  //   zero = 0
  //   neg  = G_SUB zero, x
  //   dst  = G_SMAX x, neg
  //
  // There is no integer v_abs instruction on AMDGPU, so divergent G_ABS is
  // expanded to this sub/smax pair.
  Register DstReg = MI.getOperand(0).getReg();
  Register SrcReg = MI.getOperand(1).getReg();
  LLT Ty = MRI.getType(DstReg);

  Register Zero;
  if (Ty == V2S16) {
    // buildConstant cannot produce a V2S16 directly; pack two S16 zeros.
    Register Zero16 = B.buildConstant({VgprRB, S16}, 0).getReg(0);
    Zero = B.buildBuildVector({VgprRB, Ty}, {Zero16, Zero16}).getReg(0);
  } else {
    assert((Ty == S32 || Ty == S16) && "unexpected type for AbsToNegMax");
    Zero = B.buildConstant({VgprRB, Ty}, 0).getReg(0);
  }

  auto Neg = B.buildSub({VgprRB, Ty}, Zero, SrcReg);
  B.buildSMax(DstReg, SrcReg, Neg);
  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lowerAbsToS32(MachineInstr &MI) {
  // Lower uniform V2S16 abs by unpacking the values to two separate SGPR
  // registers and re-emitting G_ABS on each:
  //   packed  = bitcast <2 x s16> src to s32
  //   lo      = sext_inreg packed, 16
  //   hi      = ashr packed, 16
  //   dst     = build_vector_trunc G_ABS(lo), G_ABS(hi)
  //
  // SALU only has s_abs_i32, with no direct uniform V2S16 abs. The
  // re-emitted G_ABS(SgprRB, S32) selects to s_abs_i32 on each value.
  auto Bitcast = B.buildBitcast({SgprRB_S32}, MI.getOperand(1).getReg());
  auto SextInReg = B.buildSExtInReg({SgprRB_S32}, Bitcast, 16);
  auto ShiftHi =
      B.buildAShr({SgprRB_S32}, Bitcast, B.buildConstant({SgprRB_S32}, 16));

  auto AbsLo = B.buildInstr(AMDGPU::G_ABS, {{SgprRB_S32}}, {SextInReg});
  auto AbsHi = B.buildInstr(AMDGPU::G_ABS, {{SgprRB_S32}}, {ShiftHi});
  B.buildBuildVectorTrunc(MI.getOperand(0).getReg(),
                          {AbsLo.getReg(0), AbsHi.getReg(0)});

  MI.eraseFromParent();
  return true;
}

bool RegBankLegalizeHelper::lower(MachineInstr &MI,
                                  const RegBankLLTMapping &Mapping,
                                  WaterfallInfo &WFI) {

  switch (Mapping.LoweringMethod) {
  case DoNotLower:
    break;
  case VccExtToSel:
    return lowerVccExtToSel(MI);
  case UniExtToSel: {
    LLT Ty = MRI.getType(MI.getOperand(0).getReg());
    auto True = B.buildConstant({SgprRB, Ty},
                                MI.getOpcode() == AMDGPU::G_SEXT ? -1 : 1);
    auto False = B.buildConstant({SgprRB, Ty}, 0);
    // Input to G_{Z|S}EXT is 'Legalizer legal' S1. Most common case is compare.
    // We are making select here. S1 cond was already 'any-extended to S32' +
    // 'AND with 1 to clean high bits' by Sgpr32AExtBoolInReg.
    B.buildSelect(MI.getOperand(0).getReg(), MI.getOperand(1).getReg(), True,
                  False);
    MI.eraseFromParent();
    return true;
  }
  case UnpackBitShift:
    return lowerUnpackBitShift(MI);
  case UnpackMinMax:
    return lowerUnpackMinMax(MI);
  case ScalarizeToS16:
    return lowerSplitTo16(MI);
  case Ext32To64: {
    const RegisterBank *RB = MRI.getRegBank(MI.getOperand(0).getReg());
    MachineInstrBuilder Hi;
    switch (MI.getOpcode()) {
    case AMDGPU::G_ZEXT: {
      Hi = B.buildConstant({RB, S32}, 0);
      break;
    }
    case AMDGPU::G_SEXT: {
      // Replicate sign bit from 32-bit extended part.
      auto ShiftAmt = B.buildConstant({RB, S32}, 31);
      Hi = B.buildAShr({RB, S32}, MI.getOperand(1).getReg(), ShiftAmt);
      break;
    }
    case AMDGPU::G_ANYEXT: {
      Hi = B.buildUndef({RB, S32});
      break;
    }
    default:
      reportGISelFailure(MF, MORE, "amdgpu-regbanklegalize",
                         "AMDGPU RegBankLegalize: Ext32To64, unsuported opcode",
                         MI);
      return false;
    }

    B.buildMergeLikeInstr(MI.getOperand(0).getReg(),
                          {MI.getOperand(1).getReg(), Hi});
    MI.eraseFromParent();
    return true;
  }
  case UniCstExt: {
    uint64_t ConstVal = MI.getOperand(1).getCImm()->getZExtValue();
    B.buildConstant(MI.getOperand(0).getReg(), ConstVal);

    MI.eraseFromParent();
    return true;
  }
  case VgprToVccCopy: {
    Register Src = MI.getOperand(1).getReg();
    LLT Ty = MRI.getType(Src);
    // Take lowest bit from each lane and put it in lane mask.
    // Lowering via compare, but we need to clean high bits first as compare
    // compares all bits in register.
    Register BoolSrc = MRI.createVirtualRegister({VgprRB, Ty});
    if (Ty == S64) {
      auto Src64 = B.buildUnmerge(VgprRB_S32, Src);
      auto One = B.buildConstant(VgprRB_S32, 1);
      auto AndLo = B.buildAnd(VgprRB_S32, Src64.getReg(0), One);
      auto Zero = B.buildConstant(VgprRB_S32, 0);
      auto AndHi = B.buildAnd(VgprRB_S32, Src64.getReg(1), Zero);
      B.buildMergeLikeInstr(BoolSrc, {AndLo, AndHi});
    } else {
      assert(Ty == S32 || Ty == S16);
      auto One = B.buildConstant({VgprRB, Ty}, 1);
      B.buildAnd(BoolSrc, Src, One);
    }
    auto Zero = B.buildConstant({VgprRB, Ty}, 0);
    B.buildICmp(CmpInst::ICMP_NE, MI.getOperand(0).getReg(), BoolSrc, Zero);
    MI.eraseFromParent();
    return true;
  }
  case V_BFE:
    return lowerV_BFE(MI);
  case S_BFE:
    return lowerS_BFE(MI);
  case UniMAD64:
    return lowerUniMAD64(MI);
  case UniMul64: {
    B.buildMul(MI.getOperand(0), MI.getOperand(1), MI.getOperand(2));
    MI.eraseFromParent();
    return true;
  }
  case DivSMulToMAD: {
    auto Op1 = B.buildTrunc(VgprRB_S32, MI.getOperand(1));
    auto Op2 = B.buildTrunc(VgprRB_S32, MI.getOperand(2));
    auto Zero = B.buildConstant({VgprRB, S64}, 0);

    unsigned NewOpc = MI.getOpcode() == AMDGPU::G_AMDGPU_S_MUL_U64_U32
                          ? AMDGPU::G_AMDGPU_MAD_U64_U32
                          : AMDGPU::G_AMDGPU_MAD_I64_I32;

    B.buildInstr(NewOpc, {MI.getOperand(0).getReg(), {SgprRB, S32}},
                 {Op1, Op2, Zero});
    MI.eraseFromParent();
    return true;
  }
  case SplitTo32:
    return lowerSplitTo32(MI);
  case SplitTo32Mul:
    return lowerSplitTo32Mul(MI);
  case SplitTo32Select:
    return lowerSplitTo32Select(MI);
  case SplitTo32SExtInReg:
    return lowerSplitTo32SExtInReg(MI);
  case SplitLoad: {
    LLT DstTy = MRI.getType(MI.getOperand(0).getReg());
    unsigned Size = DstTy.getSizeInBits();
    // Even split to 128-bit loads
    if (Size > 128) {
      LLT B128;
      if (DstTy.isVector()) {
        LLT EltTy = DstTy.getElementType();
        B128 = LLT::fixed_vector(128 / EltTy.getSizeInBits(), EltTy);
      } else {
        B128 = LLT::scalar(128);
      }
      if (Size / 128 == 2)
        splitLoad(MI, {B128, B128});
      else if (Size / 128 == 4)
        splitLoad(MI, {B128, B128, B128, B128});
      else {
        reportGISelFailure(MF, MORE, "amdgpu-regbanklegalize",
                           "AMDGPU RegBankLegalize: SplitLoad, unsuported type",
                           MI);
        return false;
      }
    }
    // 64 and 32 bit load
    else if (DstTy == S96)
      splitLoad(MI, {S64, S32}, S32);
    else if (DstTy == V3S32)
      splitLoad(MI, {V2S32, S32}, S32);
    else if (DstTy == V6S16)
      splitLoad(MI, {V4S16, V2S16}, V2S16);
    else {
      reportGISelFailure(MF, MORE, "amdgpu-regbanklegalize",
                         "AMDGPU RegBankLegalize: SplitLoad, unsuported type",
                         MI);
      return false;
    }
    return true;
  }
  case WidenLoad: {
    LLT DstTy = MRI.getType(MI.getOperand(0).getReg());
    if (DstTy == S96)
      widenLoad(MI, S128);
    else if (DstTy == V3S32)
      widenLoad(MI, V4S32, S32);
    else if (DstTy == V6S16)
      widenLoad(MI, V8S16, V2S16);
    else {
      reportGISelFailure(MF, MORE, "amdgpu-regbanklegalize",
                         "AMDGPU RegBankLegalize: WidenLoad, unsuported type",
                         MI);
      return false;
    }
    return true;
  }
  case UnpackAExt:
    return lowerUnpackAExt(MI);
  case WidenMMOToS32:
    return widenMMOToS32(cast<GAnyLoad>(MI));
  case VerifyAllSgpr: {
    assert(llvm::all_of(MI.operands(), [&](const MachineOperand &Op) {
      return MRI.getRegBankOrNull(Op.getReg()) == SgprRB;
    }));
    return true;
  }
  case ApplyAllVgpr: {
    assert(llvm::all_of(MI.defs(), [&](const MachineOperand &Op) {
      return MRI.getRegBankOrNull(Op.getReg()) == VgprRB;
    }));
    B.setInstrAndDebugLoc(MI);
    for (unsigned i = MI.getNumDefs(); i < MI.getNumOperands(); ++i) {
      MachineOperand &Op = MI.getOperand(i);
      if (!Op.isReg())
        continue;
      Register Reg = Op.getReg();
      if (MRI.getRegBank(Reg) != VgprRB) {
        auto Copy = B.buildCopy({VgprRB, MRI.getType(Reg)}, Reg);
        Op.setReg(Copy.getReg(0));
      }
    }
    return true;
  }
  case UnmergeToShiftTrunc: {
    GUnmerge *Unmerge = dyn_cast<GUnmerge>(&MI);
    LLT Ty = MRI.getType(Unmerge->getSourceReg());
    if (Ty.getSizeInBits() % 32 != 0) {
      reportGISelFailure(MF, MORE, "amdgpu-regbanklegalize",
                         "AMDGPU RegBankLegalize: unmerge not multiple of 32",
                         MI);
      return false;
    }

    B.setInstrAndDebugLoc(MI);
    if (Ty.getSizeInBits() > 32) {
      auto UnmergeV2S16 =
          B.buildUnmerge({SgprRB, V2S16}, Unmerge->getSourceReg());
      for (unsigned i = 0; i < UnmergeV2S16->getNumDefs(); ++i) {
        auto [Dst0S32, Dst1S32] =
            unpackAExt(UnmergeV2S16->getOperand(i).getReg());
        B.buildTrunc(MI.getOperand(i * 2).getReg(), Dst0S32);
        B.buildTrunc(MI.getOperand(i * 2 + 1).getReg(), Dst1S32);
      }
    } else {
      auto [Dst0S32, Dst1S32] = unpackAExt(MI.getOperand(2).getReg());
      B.buildTrunc(MI.getOperand(0).getReg(), Dst0S32);
      B.buildTrunc(MI.getOperand(1).getReg(), Dst1S32);
    }

    MI.eraseFromParent();
    return true;
  }
  case AextToS32InIncomingBlockGPHI: {
    Register Dst = MI.getOperand(0).getReg();
    Register NewDst = MRI.createVirtualRegister(SgprRB_S32);
    B.setInsertPt(*MI.getParent(), MI.getParent()->getFirstNonPHI());
    MI.getOperand(0).setReg(NewDst);
    B.buildTrunc(Dst, NewDst);

    for (unsigned i = 1; i < MI.getNumOperands(); i += 2) {
      Register UseReg = MI.getOperand(i).getReg();

      auto DefMI = MRI.getVRegDef(UseReg)->getIterator();
      MachineBasicBlock *DefMBB = DefMI->getParent();

      B.setInsertPt(*DefMBB, DefMBB->SkipPHIsAndLabels(std::next(DefMI)));

      auto NewUse = B.buildAnyExt(SgprRB_S32, UseReg);
      MI.getOperand(i).setReg(NewUse.getReg(0));
    }
    break;
  }
  case VerifyAllSgprGPHI: {
    assert(llvm::all_of(MI.operands(), [&](const MachineOperand &Op) {
      if (Op.isMBB())
        return true;
      return MRI.getRegBankOrNull(Op.getReg()) == SgprRB;
    }));
    return true;
  }
  case VerifyAllSgprOrVgprGPHI: {
    assert(MRI.getRegBankOrNull(MI.getOperand(0).getReg()) == VgprRB);
    assert(llvm::all_of(MI.operands(), [&](const MachineOperand &Op) {
      if (Op.isMBB())
        return true;
      const RegisterBank *RB = MRI.getRegBankOrNull(Op.getReg());
      return RB == VgprRB || RB == SgprRB;
    }));
    return true;
  }
  case ApplyINTRIN_IMAGE: {
    const AMDGPU::RsrcIntrinsic *RSrcIntrin =
        AMDGPU::lookupRsrcIntrinsic(AMDGPU::getIntrinsicID(MI));
    assert(RSrcIntrin && RSrcIntrin->IsImage);
    // The reported argument index is relative to the IR intrinsic call
    // arguments, so shift by the number of defs and the intrinsic ID.
    unsigned RsrcIdx = RSrcIntrin->RsrcArg + MI.getNumExplicitDefs() + 1;
    return applyRegisterBanksVgprWithSgprRsrc(MI, RsrcIdx);
  }
  case ApplyBVH_INTERSECT_RAY: {
    // Rsrc is the last register operand. Base BVH trails an A16 immediate
    // after rsrc; dual/BVH8 do not. Scan backwards for the last virtual
    // register.
    unsigned RsrcIdx = MI.getNumOperands();
    while (RsrcIdx-- > MI.getNumExplicitDefs()) {
      const MachineOperand &Op = MI.getOperand(RsrcIdx);
      if (Op.isReg() && Op.getReg().isVirtual())
        break;
    }
    return applyRegisterBanksVgprWithSgprRsrc(MI, RsrcIdx);
  }
  case SplitBitCount64To32:
    return lowerSplitBitCount64To32(MI);
  case ExtrVecEltToSel:
    return lowerExtrVecEltToSel(MI);
  case ExtrVecEltTo32:
    return lowerExtrVecEltTo32(MI);
  case InsVecEltToSel:
    return lowerInsVecEltToSel(MI);
  case InsVecEltTo32:
    return lowerInsVecEltTo32(MI);
  case AbsToNegMax:
    return lowerAbsToNegMax(MI);
  case AbsToS32:
    return lowerAbsToS32(MI);
  }

  if (!WFI.SgprWaterfallOperandRegs.empty()) {
    if (!executeInWaterfallLoop(B, WFI))
      return false;
  }
  return true;
}

LLT RegBankLegalizeHelper::getTyFromID(RegBankLLTMappingApplyID ID) {
  switch (ID) {
  case Vcc:
  case UniInVcc:
    return LLT::scalar(1);
  case Sgpr16:
  case Vgpr16:
  case UniInVgprS16:
    return LLT::scalar(16);
  case Sgpr32:
  case Sgpr32_WF:
  case Sgpr32Trunc:
  case Sgpr32AExt:
  case Sgpr32AExtBoolInReg:
  case Sgpr32SExt:
  case Sgpr32ZExt:
  case UniInVgprS32:
  case Sgpr32ToVgprDst:
  case Vgpr32:
  case Vgpr32AExt:
  case Vgpr32SExt:
  case Vgpr32ZExt:
    return LLT::scalar(32);
  case Sgpr64:
  case Vgpr64:
  case UniInVgprS64:
  case Sgpr64ToVgprDst:
    return LLT::scalar(64);
  case Sgpr128:
  case Vgpr128:
    return LLT::scalar(128);
  case SgprP0:
  case SgprP0Call_WF:
  case VgprP0:
    return LLT::pointer(0, 64);
  case SgprP1:
  case VgprP1:
    return LLT::pointer(1, 64);
  case SgprP2:
  case VgprP2:
    return LLT::pointer(2, 32);
  case SgprP3:
  case VgprP3:
    return LLT::pointer(3, 32);
  case SgprP4:
  case SgprP4Call_WF:
  case VgprP4:
    return LLT::pointer(4, 64);
  case SgprP5:
  case VgprP5:
    return LLT::pointer(5, 32);
  case SgprP8:
    return LLT::pointer(8, 128);
  case SgprV2S16:
  case VgprV2S16:
  case UniInVgprV2S16:
    return LLT::fixed_vector(2, 16);
  case SgprV2S32:
  case VgprV2S32:
  case UniInVgprV2S32:
    return LLT::fixed_vector(2, 32);
  case VgprV3S32:
    return LLT::fixed_vector(3, 32);
  case VgprV4S16:
    return LLT::fixed_vector(4, 16);
  case SgprV4S32:
  case SgprV4S32_WF:
  case SgprV4S32_ReadFirstLane:
  case VgprV4S32:
  case UniInVgprV4S32:
    return LLT::fixed_vector(4, 32);
  case VgprV8S32:
    return LLT::fixed_vector(8, 32);
  case VgprV2S64:
  case UniInVgprV2S64:
    return LLT::fixed_vector(2, 64);
  case VgprV6S32:
    return LLT::fixed_vector(6, 32);
  case VgprV32S16:
    return LLT::fixed_vector(32, 16);
  case VgprV32S32:
    return LLT::fixed_vector(32, 32);
  default:
    return LLT();
  }
}

LLT RegBankLegalizeHelper::getBTyFromID(RegBankLLTMappingApplyID ID, LLT Ty) {
  switch (ID) {
  case SgprB32:
  case VgprB32:
  case SgprB32_M0:
  case SgprB32_ReadFirstLane:
  case UniInVgprB32:
    if (Ty == LLT::scalar(32) || Ty == LLT::fixed_vector(2, 16) ||
        isAnyPtr(Ty, 32))
      return Ty;
    return LLT();
  case SgprPtr32:
  case VgprPtr32:
    return isAnyPtr(Ty, 32) ? Ty : LLT();
  case SgprPtr64:
  case VgprPtr64:
    return isAnyPtr(Ty, 64) ? Ty : LLT();
  case SgprPtr128:
  case VgprPtr128:
    return isAnyPtr(Ty, 128) ? Ty : LLT();
  case SgprB64:
  case VgprB64:
  case SgprB64_ReadFirstLane:
  case UniInVgprB64:
    if (Ty == LLT::scalar(64) || Ty == LLT::fixed_vector(2, 32) ||
        Ty == LLT::fixed_vector(4, 16) || isAnyPtr(Ty, 64))
      return Ty;
    return LLT();
  case SgprB96:
  case VgprB96:
  case UniInVgprB96:
    if (Ty == LLT::scalar(96) || Ty == LLT::fixed_vector(3, 32) ||
        Ty == LLT::fixed_vector(6, 16))
      return Ty;
    return LLT();
  case SgprB128:
  case VgprB128:
  case UniInVgprB128:
    if (Ty == LLT::scalar(128) || Ty == LLT::fixed_vector(4, 32) ||
        Ty == LLT::fixed_vector(2, 64) || Ty == LLT::fixed_vector(8, 16) ||
        isAnyPtr(Ty, 128))
      return Ty;
    return LLT();
  case VgprB160:
  case UniInVgprB160:
    if (Ty.getSizeInBits() == 160)
      return Ty;
    return LLT();
  case SgprB256:
  case VgprB256:
  case UniInVgprB256:
    if (Ty == LLT::scalar(256) || Ty == LLT::fixed_vector(8, 32) ||
        Ty == LLT::fixed_vector(4, 64) || Ty == LLT::fixed_vector(16, 16))
      return Ty;
    return LLT();
  case SgprB512:
  case VgprB512:
  case UniInVgprB512:
    if (Ty == LLT::scalar(512) || Ty == LLT::fixed_vector(16, 32) ||
        Ty == LLT::fixed_vector(8, 64))
      return Ty;
    return LLT();
  case SgprBRC: {
    const SIRegisterInfo *TRI =
        static_cast<const SIRegisterInfo *>(MRI.getTargetRegisterInfo());
    unsigned LLTSize = Ty.getSizeInBits();
    if (LLTSize >= 32 && TRI->getSGPRClassForBitWidth(LLTSize))
      return Ty;
    return LLT();
  }
  case VgprBRC: {
    const SIRegisterInfo *TRI =
        static_cast<const SIRegisterInfo *>(MRI.getTargetRegisterInfo());
    if (TRI->getSGPRClassForBitWidth(Ty.getSizeInBits()))
      return Ty;
    return LLT();
  }
  default:
    return LLT();
  }
}

const RegisterBank *
RegBankLegalizeHelper::getRegBankFromID(RegBankLLTMappingApplyID ID) {
  switch (ID) {
  case Vcc:
    return VccRB;
  case Sgpr16:
  case Sgpr32:
  case Sgpr32_WF:
  case Sgpr64:
  case Sgpr128:
  case SgprP0:
  case SgprP0Call_WF:
  case SgprP1:
  case SgprP2:
  case SgprP3:
  case SgprP4:
  case SgprP4Call_WF:
  case SgprP5:
  case SgprP8:
  case SgprPtr32:
  case SgprPtr64:
  case SgprPtr128:
  case SgprV2S16:
  case SgprV2S32:
  case SgprV4S32:
  case SgprV4S32_WF:
  case SgprV4S32_ReadFirstLane:
  case SgprB32:
  case SgprB64:
  case SgprB96:
  case SgprB128:
  case SgprB256:
  case SgprB512:
  case SgprBRC:
  case UniInVcc:
  case UniInVgprS16:
  case UniInVgprS32:
  case UniInVgprS64:
  case UniInVgprV2S16:
  case UniInVgprV2S32:
  case UniInVgprV4S32:
  case UniInVgprV2S64:
  case UniInVgprB32:
  case UniInVgprB64:
  case UniInVgprB96:
  case UniInVgprB128:
  case UniInVgprB160:
  case UniInVgprB256:
  case UniInVgprB512:
  case Sgpr32Trunc:
  case Sgpr32AExt:
  case Sgpr32AExtBoolInReg:
  case Sgpr32SExt:
  case Sgpr32ZExt:
    return SgprRB;
  case AgprAnyTy:
    return AgprRB;
  case Vgpr16:
  case Vgpr32:
  case Vgpr64:
  case Vgpr128:
  case VgprP0:
  case VgprP1:
  case VgprP2:
  case VgprP3:
  case VgprP4:
  case VgprP5:
  case VgprPtr32:
  case VgprPtr64:
  case VgprPtr128:
  case VgprV2S16:
  case VgprV2S32:
  case VgprV2S64:
  case VgprV3S32:
  case VgprV4S16:
  case VgprV4S32:
  case VgprV6S32:
  case VgprV8S32:
  case VgprV32S16:
  case VgprB32:
  case VgprB64:
  case VgprB96:
  case VgprB128:
  case VgprB160:
  case VgprB256:
  case VgprB512:
  case VgprBRC:
  case VgprAnyTy:
  case Vgpr32AExt:
  case Vgpr32SExt:
  case Vgpr32ZExt:
  case Sgpr32ToVgprDst:
  case Sgpr64ToVgprDst:
    return VgprRB;
  default:
    return nullptr;
  }
}

bool RegBankLegalizeHelper::applyMappingDst(
    MachineInstr &MI, unsigned &OpIdx,
    const SmallVectorImpl<RegBankLLTMappingApplyID> &MethodIDs) {
  // Defs start from operand 0
  for (; OpIdx < MethodIDs.size(); ++OpIdx) {
    if (MethodIDs[OpIdx] == None)
      continue;
    MachineOperand &Op = MI.getOperand(OpIdx);
    Register Reg = Op.getReg();
    LLT Ty = MRI.getType(Reg);
    [[maybe_unused]] const RegisterBank *RB = MRI.getRegBank(Reg);

    switch (MethodIDs[OpIdx]) {
    // vcc, sgpr and vgpr scalars, pointers and vectors
    case Vcc:
    case Sgpr16:
    case Sgpr32:
    case Sgpr64:
    case Sgpr128:
    case SgprP0:
    case SgprP1:
    case SgprP3:
    case SgprP4:
    case SgprP5:
    case SgprP8:
    case SgprV2S16:
    case SgprV2S32:
    case SgprV4S32:
    case Vgpr16:
    case Vgpr32:
    case Vgpr64:
    case Vgpr128:
    case VgprP0:
    case VgprP1:
    case VgprP2:
    case VgprP3:
    case VgprP4:
    case VgprP5:
    case VgprV2S16:
    case VgprV2S32:
    case VgprV2S64:
    case VgprV3S32:
    case VgprV4S16:
    case VgprV4S32:
    case VgprV6S32:
    case VgprV8S32:
    case VgprV32S16: {
      assert(Ty == getTyFromID(MethodIDs[OpIdx]));
      assert(RB == getRegBankFromID(MethodIDs[OpIdx]));
      break;
    }
    // sgpr and vgpr B-types
    case SgprB32:
    case SgprB64:
    case SgprB96:
    case SgprB128:
    case SgprB256:
    case SgprB512:
    case SgprBRC:
    case SgprPtr32:
    case SgprPtr64:
    case SgprPtr128:
    case VgprB32:
    case VgprB64:
    case VgprB96:
    case VgprB128:
    case VgprB160:
    case VgprB256:
    case VgprB512:
    case VgprBRC:
    case VgprPtr32:
    case VgprPtr64:
    case VgprPtr128: {
      assert(Ty == getBTyFromID(MethodIDs[OpIdx], Ty));
      assert(RB == getRegBankFromID(MethodIDs[OpIdx]));
      break;
    }
    case VgprAnyTy: {
      assert(RB == VgprRB);
      break;
    }
    case AgprAnyTy: {
      if (RB == AgprRB)
        break;
      Register NewAgprDst = MRI.createVirtualRegister({AgprRB, Ty});
      Op.setReg(NewAgprDst);
      if (!MRI.use_nodbg_empty(Reg))
        B.buildCopy(Reg, NewAgprDst);
      break;
    }
    // uniform in vcc/vgpr: scalars, vectors and B-types
    case UniInVcc: {
      assert(Ty == S1);
      assert(RB == SgprRB);
      Register NewDst = MRI.createVirtualRegister(VccRB_S1);
      Op.setReg(NewDst);
      if (!MRI.use_empty(Reg)) {
        auto CopyS32_Vcc =
            B.buildInstr(AMDGPU::G_AMDGPU_COPY_SCC_VCC, {SgprRB_S32}, {NewDst});
        B.buildTrunc(Reg, CopyS32_Vcc);
      }
      break;
    }
    case UniInVgprS16: {
      assert(Ty == getTyFromID(MethodIDs[OpIdx]));
      assert(RB == SgprRB);
      Register NewVgprDstS16 = MRI.createVirtualRegister({VgprRB, S16});
      Register NewVgprDstS32 = MRI.createVirtualRegister({VgprRB, S32});
      Register NewSgprDstS32 = MRI.createVirtualRegister({SgprRB, S32});
      Op.setReg(NewVgprDstS16);
      B.buildAnyExt(NewVgprDstS32, NewVgprDstS16);
      buildReadAnyLane(B, NewSgprDstS32, NewVgprDstS32, RBI);
      B.buildTrunc(Reg, NewSgprDstS32);
      break;
    }
    case UniInVgprS32:
    case UniInVgprS64:
    case UniInVgprV2S16:
    case UniInVgprV2S32:
    case UniInVgprV4S32:
    case UniInVgprV2S64: {
      assert(Ty == getTyFromID(MethodIDs[OpIdx]));
      assert(RB == SgprRB);
      Register NewVgprDst = MRI.createVirtualRegister({VgprRB, Ty});
      Op.setReg(NewVgprDst);
      buildReadAnyLane(B, Reg, NewVgprDst, RBI);
      break;
    }
    case UniInVgprB32:
    case UniInVgprB64:
    case UniInVgprB96:
    case UniInVgprB128:
    case UniInVgprB160:
    case UniInVgprB256:
    case UniInVgprB512: {
      assert(Ty == getBTyFromID(MethodIDs[OpIdx], Ty));
      assert(RB == SgprRB);
      Register NewVgprDst = MRI.createVirtualRegister({VgprRB, Ty});
      Op.setReg(NewVgprDst);
      AMDGPU::buildReadAnyLane(B, Reg, NewVgprDst, RBI);
      break;
    }
    // sgpr trunc
    case Sgpr32Trunc: {
      assert(Ty.getSizeInBits() < 32);
      assert(RB == SgprRB);
      Register NewDst = MRI.createVirtualRegister(SgprRB_S32);
      Op.setReg(NewDst);
      if (!MRI.use_empty(Reg))
        B.buildTrunc(Reg, NewDst);
      break;
    }
    case Sgpr32ToVgprDst:
    case Sgpr64ToVgprDst: {
      assert(Ty == getTyFromID(MethodIDs[OpIdx]));
      assert(RB == VgprRB);
      Op.setReg(MRI.createVirtualRegister({SgprRB, Ty}));
      B.buildCopy(Reg, Op.getReg());
      break;
    }
    case InvalidMapping: {
      reportGISelFailure(
          MF, MORE, "amdgpu-regbanklegalize",
          "AMDGPU RegBankLegalize: missing fast rule ('Div' or 'Uni') for", MI);
      return false;
    }
    default:
      reportGISelFailure(
          MF, MORE, "amdgpu-regbanklegalize",
          "AMDGPU RegBankLegalize: applyMappingDst, ID not supported", MI);
      return false;
    }
  }

  return true;
}

bool RegBankLegalizeHelper::applyMappingSrc(
    MachineInstr &MI, unsigned &OpIdx,
    const SmallVectorImpl<RegBankLLTMappingApplyID> &MethodIDs,
    WaterfallInfo &WFI) {
  for (unsigned i = 0; i < MethodIDs.size(); ++OpIdx, ++i) {
    if (MethodIDs[i] == None || MethodIDs[i] == IntrId || MethodIDs[i] == Imm)
      continue;

    MachineOperand &Op = MI.getOperand(OpIdx);
    Register Reg = Op.getReg();
    LLT Ty = MRI.getType(Reg);
    const RegisterBank *RB = MRI.getRegBank(Reg);

    switch (MethodIDs[i]) {
    case Vcc: {
      assert(Ty == S1);
      assert(RB == VccRB || RB == SgprRB);
      if (RB == SgprRB) {
        auto Aext = B.buildAnyExt(SgprRB_S32, Reg);
        auto CopyVcc_Scc =
            B.buildInstr(AMDGPU::G_AMDGPU_COPY_VCC_SCC, {VccRB_S1}, {Aext});
        Op.setReg(CopyVcc_Scc.getReg(0));
      }
      break;
    }
    // sgpr scalars, pointers and vectors
    case Sgpr16:
    case Sgpr32:
    case Sgpr64:
    case Sgpr128:
    case SgprP0:
    case SgprP1:
    case SgprP3:
    case SgprP4:
    case SgprP5:
    case SgprP8:
    case SgprV2S16:
    case SgprV2S32:
    case SgprV4S32: {
      assert(Ty == getTyFromID(MethodIDs[i]));
      assert(RB == getRegBankFromID(MethodIDs[i]));
      break;
    }
    // sgpr B-types
    case SgprB32:
    case SgprB64:
    case SgprB96:
    case SgprB128:
    case SgprB256:
    case SgprB512:
    case SgprBRC:
    case SgprPtr32:
    case SgprPtr64:
    case SgprPtr128: {
      assert(Ty == getBTyFromID(MethodIDs[i], Ty));
      assert(RB == getRegBankFromID(MethodIDs[i]));
      break;
    }
    // vgpr scalars, pointers and vectors
    case Vgpr16:
    case Vgpr32:
    case Vgpr64:
    case Vgpr128:
    case VgprP0:
    case VgprP1:
    case VgprP2:
    case VgprP3:
    case VgprP4:
    case VgprP5:
    case VgprV2S16:
    case VgprV2S32:
    case VgprV2S64:
    case VgprV3S32:
    case VgprV4S16:
    case VgprV4S32:
    case VgprV6S32:
    case VgprV8S32:
    case VgprV32S16:
    case VgprV32S32: {
      assert(Ty == getTyFromID(MethodIDs[i]));
      if (RB != VgprRB) {
        auto CopyToVgpr = B.buildCopy({VgprRB, Ty}, Reg);
        Op.setReg(CopyToVgpr.getReg(0));
      }
      break;
    }
    // vgpr B-types
    case VgprB32:
    case VgprB64:
    case VgprB96:
    case VgprB128:
    case VgprB160:
    case VgprB256:
    case VgprB512:
    case VgprBRC:
    case VgprPtr32:
    case VgprPtr64:
    case VgprPtr128: {
      assert(Ty == getBTyFromID(MethodIDs[i], Ty));
      if (RB != VgprRB) {
        auto CopyToVgpr = B.buildCopy({VgprRB, Ty}, Reg);
        Op.setReg(CopyToVgpr.getReg(0));
      }
      break;
    }
    case VgprAnyTy: {
      if (RB != VgprRB) {
        auto CopyToVgpr = B.buildCopy({VgprRB, Ty}, Reg);
        Op.setReg(CopyToVgpr.getReg(0));
      }
      break;
    }
    case AgprAnyTy: {
      if (RB != AgprRB) {
        auto CopyToAgpr = B.buildCopy({AgprRB, Ty}, Reg);
        Op.setReg(CopyToAgpr.getReg(0));
      }
      break;
    }
    // sgpr waterfall, scalars, and vectors
    case Sgpr32_WF:
    case SgprV4S32_WF: {
      assert(Ty == getTyFromID(MethodIDs[i]));
      if (RB != SgprRB) {
        WFI.SgprWaterfallOperandRegs.insert(Reg);
        if (!WFI.Start.isValid()) {
          WFI.Start = MI.getIterator();
          WFI.End = std::next(MI.getIterator());
        }
      }
      break;
    }
    case SgprP0Call_WF:
    case SgprP4Call_WF: {
      assert(Ty == getTyFromID(MethodIDs[i]));
      if (RB != SgprRB) {
        WFI.SgprWaterfallOperandRegs.insert(Reg);

        // Find the ADJCALLSTACKUP before the call.
        MachineBasicBlock::iterator Start = MI.getIterator();
        while (Start->getOpcode() != AMDGPU::ADJCALLSTACKUP)
          --Start;

        // Find the ADJCALLSTACKDOWN after the call (include it in range).
        MachineBasicBlock::iterator End = MI.getIterator();
        while (End->getOpcode() != AMDGPU::ADJCALLSTACKDOWN)
          ++End;
        ++End;

        B.setInsertPt(*MI.getParent(), Start);
        WFI.Start = Start;
        WFI.End = End;
      }
      break;
    }
    case SgprB32_M0:
    case SgprB32_ReadFirstLane:
    case SgprB64_ReadFirstLane: {
      assert(Ty == getBTyFromID(MethodIDs[i], Ty));
      if (RB == SgprRB)
        break;
      assert(RB == VgprRB);
      Register NewSGPR = MRI.createVirtualRegister({SgprRB, Ty});
      buildReadFirstLane(B, NewSGPR, Op.getReg(), RBI);
      Op.setReg(NewSGPR);
      break;
    }
    case SgprV4S32_ReadFirstLane: {
      assert(Ty == getTyFromID(MethodIDs[i]));
      if (RB == SgprRB)
        break;
      assert(RB == VgprRB);
      Register NewSGPR = MRI.createVirtualRegister({SgprRB, Ty});
      buildReadFirstLane(B, NewSGPR, Op.getReg(), RBI);
      Op.setReg(NewSGPR);
      break;
    }
    // sgpr and vgpr scalars with extend
    case Sgpr32AExt: {
      // Note: this ext allows S1, and it is meant to be combined away.
      assert(Ty.getSizeInBits() < 32);
      assert(RB == SgprRB);
      auto Aext = B.buildAnyExt(SgprRB_S32, Reg);
      Op.setReg(Aext.getReg(0));
      break;
    }
    case Sgpr32AExtBoolInReg: {
      // Note: this ext allows S1, and it is meant to be combined away.
      assert(Ty.getSizeInBits() == 1);
      assert(RB == SgprRB);
      auto Aext = B.buildAnyExt(SgprRB_S32, Reg);
      // Zext SgprS1 is not legal, make AND with 1 instead. This instruction is
      // most of times meant to be combined away in AMDGPURegBankCombiner.
      auto Cst1 = B.buildConstant(SgprRB_S32, 1);
      auto BoolInReg = B.buildAnd(SgprRB_S32, Aext, Cst1);
      Op.setReg(BoolInReg.getReg(0));
      break;
    }
    case Sgpr32SExt: {
      assert(1 < Ty.getSizeInBits() && Ty.getSizeInBits() < 32);
      assert(RB == SgprRB);
      auto Sext = B.buildSExt(SgprRB_S32, Reg);
      Op.setReg(Sext.getReg(0));
      break;
    }
    case Sgpr32ZExt: {
      assert(1 < Ty.getSizeInBits() && Ty.getSizeInBits() < 32);
      assert(RB == SgprRB);
      auto Zext = B.buildZExt({SgprRB, S32}, Reg);
      Op.setReg(Zext.getReg(0));
      break;
    }
    case Vgpr32AExt: {
      assert(Ty.getSizeInBits() < 32);
      assert(RB == VgprRB);
      auto Aext = B.buildAnyExt({VgprRB, S32}, Reg);
      Op.setReg(Aext.getReg(0));
      break;
    }
    case Vgpr32SExt: {
      // Note this ext allows S1, and it is meant to be combined away.
      assert(Ty.getSizeInBits() < 32);
      assert(RB == VgprRB);
      auto Sext = B.buildSExt({VgprRB, S32}, Reg);
      Op.setReg(Sext.getReg(0));
      break;
    }
    case Vgpr32ZExt: {
      // Note this ext allows S1, and it is meant to be combined away.
      assert(Ty.getSizeInBits() < 32);
      assert(RB == VgprRB);
      auto Zext = B.buildZExt({VgprRB, S32}, Reg);
      Op.setReg(Zext.getReg(0));
      break;
    }
    default:
      reportGISelFailure(
          MF, MORE, "amdgpu-regbanklegalize",
          "AMDGPU RegBankLegalize: applyMappingSrc, ID not supported", MI);
      return false;
    }
  }
  return true;
}

[[maybe_unused]] static bool verifyRegBankOnOperands(MachineInstr &MI,
                                                     const RegisterBank *RB,
                                                     MachineRegisterInfo &MRI,
                                                     unsigned StartOpIdx,
                                                     unsigned EndOpIdx) {
  for (unsigned i = StartOpIdx; i <= EndOpIdx; ++i) {
    if (MRI.getRegBankOrNull(MI.getOperand(i).getReg()) != RB)
      return false;
  }
  return true;
}

bool RegBankLegalizeHelper::applyRegisterBanksVgprWithSgprRsrc(
    MachineInstr &MI, unsigned RsrcIdx) {
  const unsigned NumDefs = MI.getNumExplicitDefs();

  MachineBasicBlock *MBB = MI.getParent();
  B.setInsertPt(*MBB, MBB->SkipPHIsAndLabels(std::next(MI.getIterator())));

  // Defs are vgpr.
  for (unsigned i = 0; i < NumDefs; ++i) {
    Register Reg = MI.getOperand(i).getReg();
    if (MRI.getRegBank(Reg) == VgprRB)
      continue;

    Register NewVgprDst = MRI.createVirtualRegister({VgprRB, MRI.getType(Reg)});
    MI.getOperand(i).setReg(NewVgprDst);
    buildReadAnyLane(B, Reg, NewVgprDst, RBI);
  }

  B.setInstrAndDebugLoc(MI);

  // Register uses before RsrcIdx are vgpr.
  for (unsigned i = NumDefs; i < RsrcIdx; ++i) {
    MachineOperand &Op = MI.getOperand(i);
    if (!Op.isReg())
      continue;

    Register Reg = Op.getReg();
    if (!Reg.isVirtual())
      continue;

    if (MRI.getRegBank(Reg) == VgprRB)
      continue;

    auto Copy = B.buildCopy({VgprRB, MRI.getType(Reg)}, Reg);
    Op.setReg(Copy.getReg(0));
  }

  SmallSet<Register, 4> OpsToWaterfall;

  // Register use RsrcIdx (and later register operands) is sgpr.
  for (unsigned i = RsrcIdx; i < MI.getNumOperands(); ++i) {
    MachineOperand &Op = MI.getOperand(i);
    if (!Op.isReg())
      continue;

    Register Reg = Op.getReg();
    if (MRI.getRegBank(Reg) != SgprRB)
      OpsToWaterfall.insert(Reg);
  }

  if (!OpsToWaterfall.empty()) {
    MachineBasicBlock::iterator MII = MI.getIterator();
    executeInWaterfallLoop(B, {OpsToWaterfall, MII, std::next(MII)});
  }

  return true;
}