PPCISelDAGToDAG.cpp

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//===-- PPCISelDAGToDAG.cpp - PPC --pattern matching inst selector --------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file defines a pattern matching instruction selector for PowerPC,
// converting from a legalized dag to a PPC dag.
//
//===----------------------------------------------------------------------===//
 
#include "MCTargetDesc/PPCMCTargetDesc.h"
#include "MCTargetDesc/PPCPredicates.h"
#include "PPC.h"
#include "PPCISelLowering.h"
#include "PPCMachineFunctionInfo.h"
#include "PPCSubtarget.h"
#include "PPCTargetMachine.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/CodeGen/FunctionLoweringInfo.h"
#include "llvm/CodeGen/ISDOpcodes.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/IntrinsicsPowerPC.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Support/MachineValueType.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <iterator>
#include <limits>
#include <memory>
#include <new>
#include <tuple>
#include <utility>
 
using namespace llvm;
 
#define DEBUG_TYPE "ppc-codegen"
 
STATISTIC(NumSextSetcc,
          "Number of (sext(setcc)) nodes expanded into GPR sequence.");
STATISTIC(NumZextSetcc,
          "Number of (zext(setcc)) nodes expanded into GPR sequence.");
STATISTIC(SignExtensionsAdded,
          "Number of sign extensions for compare inputs added.");
STATISTIC(ZeroExtensionsAdded,
          "Number of zero extensions for compare inputs added.");
STATISTIC(NumLogicOpsOnComparison,
          "Number of logical ops on i1 values calculated in GPR.");
STATISTIC(OmittedForNonExtendUses,
          "Number of compares not eliminated as they have non-extending uses.");
STATISTIC(NumP9Setb,
          "Number of compares lowered to setb.");
 
// FIXME: Remove this once the bug has been fixed!
cl::opt<bool> ANDIGlueBug("expose-ppc-andi-glue-bug",
cl::desc("expose the ANDI glue bug on PPC"), cl::Hidden);
 
static cl::opt<bool>
    UseBitPermRewriter("ppc-use-bit-perm-rewriter", cl::init(true),
                       cl::desc("use aggressive ppc isel for bit permutations"),
                       cl::Hidden);
static cl::opt<bool> BPermRewriterNoMasking(
    "ppc-bit-perm-rewriter-stress-rotates",
    cl::desc("stress rotate selection in aggressive ppc isel for "
             "bit permutations"),
    cl::Hidden);
 
static cl::opt<bool> EnableBranchHint(
  "ppc-use-branch-hint", cl::init(true),
    cl::desc("Enable static hinting of branches on ppc"),
    cl::Hidden);
 
static cl::opt<bool> EnableTLSOpt(
  "ppc-tls-opt", cl::init(true),
    cl::desc("Enable tls optimization peephole"),
    cl::Hidden);
 
enum ICmpInGPRType { ICGPR_All, ICGPR_None, ICGPR_I32, ICGPR_I64,
  ICGPR_NonExtIn, ICGPR_Zext, ICGPR_Sext, ICGPR_ZextI32,
  ICGPR_SextI32, ICGPR_ZextI64, ICGPR_SextI64 };
 
static cl::opt<ICmpInGPRType> CmpInGPR(
  "ppc-gpr-icmps", cl::Hidden, cl::init(ICGPR_All),
  cl::desc("Specify the types of comparisons to emit GPR-only code for."),
  cl::values(clEnumValN(ICGPR_None, "none", "Do not modify integer comparisons."),
             clEnumValN(ICGPR_All, "all", "All possible int comparisons in GPRs."),
             clEnumValN(ICGPR_I32, "i32", "Only i32 comparisons in GPRs."),
             clEnumValN(ICGPR_I64, "i64", "Only i64 comparisons in GPRs."),
             clEnumValN(ICGPR_NonExtIn, "nonextin",
                        "Only comparisons where inputs don't need [sz]ext."),
             clEnumValN(ICGPR_Zext, "zext", "Only comparisons with zext result."),
             clEnumValN(ICGPR_ZextI32, "zexti32",
                        "Only i32 comparisons with zext result."),
             clEnumValN(ICGPR_ZextI64, "zexti64",
                        "Only i64 comparisons with zext result."),
             clEnumValN(ICGPR_Sext, "sext", "Only comparisons with sext result."),
             clEnumValN(ICGPR_SextI32, "sexti32",
                        "Only i32 comparisons with sext result."),
             clEnumValN(ICGPR_SextI64, "sexti64",
                        "Only i64 comparisons with sext result.")));
namespace {
 
  //===--------------------------------------------------------------------===//
  /// PPCDAGToDAGISel - PPC specific code to select PPC machine
  /// instructions for SelectionDAG operations.
  ///
  class PPCDAGToDAGISel : public SelectionDAGISel {
    const PPCTargetMachine &TM;
    const PPCSubtarget *Subtarget = nullptr;
    const PPCTargetLowering *PPCLowering = nullptr;
    unsigned GlobalBaseReg = 0;
 
  public:
    explicit PPCDAGToDAGISel(PPCTargetMachine &tm, CodeGenOpt::Level OptLevel)
        : SelectionDAGISel(tm, OptLevel), TM(tm) {}
 
    bool runOnMachineFunction(MachineFunction &MF) override {
      // Make sure we re-emit a set of the global base reg if necessary
      GlobalBaseReg = 0;
      Subtarget = &MF.getSubtarget<PPCSubtarget>();
      PPCLowering = Subtarget->getTargetLowering();
      if (Subtarget->hasROPProtect()) {
        // Create a place on the stack for the ROP Protection Hash.
        // The ROP Protection Hash will always be 8 bytes and aligned to 8
        // bytes.
        MachineFrameInfo &MFI = MF.getFrameInfo();
        PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
        const int Result = MFI.CreateStackObject(8, Align(8), false);
        FI->setROPProtectionHashSaveIndex(Result);
      }
      SelectionDAGISel::runOnMachineFunction(MF);
 
      return true;
    }
 
    void PreprocessISelDAG() override;
    void PostprocessISelDAG() override;
 
    /// getI16Imm - Return a target constant with the specified value, of type
    /// i16.
    inline SDValue getI16Imm(unsigned Imm, const SDLoc &dl) {
      return CurDAG->getTargetConstant(Imm, dl, MVT::i16);
    }
 
    /// getI32Imm - Return a target constant with the specified value, of type
    /// i32.
    inline SDValue getI32Imm(unsigned Imm, const SDLoc &dl) {
      return CurDAG->getTargetConstant(Imm, dl, MVT::i32);
    }
 
    /// getI64Imm - Return a target constant with the specified value, of type
    /// i64.
    inline SDValue getI64Imm(uint64_t Imm, const SDLoc &dl) {
      return CurDAG->getTargetConstant(Imm, dl, MVT::i64);
    }
 
    /// getSmallIPtrImm - Return a target constant of pointer type.
    inline SDValue getSmallIPtrImm(uint64_t Imm, const SDLoc &dl) {
      return CurDAG->getTargetConstant(
          Imm, dl, PPCLowering->getPointerTy(CurDAG->getDataLayout()));
    }
 
    /// isRotateAndMask - Returns true if Mask and Shift can be folded into a
    /// rotate and mask opcode and mask operation.
    static bool isRotateAndMask(SDNode *N, unsigned Mask, bool isShiftMask,
                                unsigned &SH, unsigned &MB, unsigned &ME);
 
    /// getGlobalBaseReg - insert code into the entry mbb to materialize the PIC
    /// base register.  Return the virtual register that holds this value.
    SDNode *getGlobalBaseReg();
 
    void selectFrameIndex(SDNode *SN, SDNode *N, uint64_t Offset = 0);
 
    // Select - Convert the specified operand from a target-independent to a
    // target-specific node if it hasn't already been changed.
    void Select(SDNode *N) override;
 
    bool tryBitfieldInsert(SDNode *N);
    bool tryBitPermutation(SDNode *N);
    bool tryIntCompareInGPR(SDNode *N);
 
    // tryTLSXFormLoad - Convert an ISD::LOAD fed by a PPCISD::ADD_TLS into
    // an X-Form load instruction with the offset being a relocation coming from
    // the PPCISD::ADD_TLS.
    bool tryTLSXFormLoad(LoadSDNode *N);
    // tryTLSXFormStore - Convert an ISD::STORE fed by a PPCISD::ADD_TLS into
    // an X-Form store instruction with the offset being a relocation coming from
    // the PPCISD::ADD_TLS.
    bool tryTLSXFormStore(StoreSDNode *N);
    /// SelectCC - Select a comparison of the specified values with the
    /// specified condition code, returning the CR# of the expression.
    SDValue SelectCC(SDValue LHS, SDValue RHS, ISD::CondCode CC,
                     const SDLoc &dl, SDValue Chain = SDValue());
 
    /// SelectAddrImmOffs - Return true if the operand is valid for a preinc
    /// immediate field.  Note that the operand at this point is already the
    /// result of a prior SelectAddressRegImm call.
    bool SelectAddrImmOffs(SDValue N, SDValue &Out) const {
      if (N.getOpcode() == ISD::TargetConstant ||
          N.getOpcode() == ISD::TargetGlobalAddress) {
        Out = N;
        return true;
      }
 
      return false;
    }
 
    /// SelectDSForm - Returns true if address N can be represented by the
    /// addressing mode of DSForm instructions (a base register, plus a signed
    /// 16-bit displacement that is a multiple of 4.
    bool SelectDSForm(SDNode *Parent, SDValue N, SDValue &Disp, SDValue &Base) {
      return PPCLowering->SelectOptimalAddrMode(Parent, N, Disp, Base, *CurDAG,
                                                Align(4)) == PPC::AM_DSForm;
    }
 
    /// SelectDQForm - Returns true if address N can be represented by the
    /// addressing mode of DQForm instructions (a base register, plus a signed
    /// 16-bit displacement that is a multiple of 16.
    bool SelectDQForm(SDNode *Parent, SDValue N, SDValue &Disp, SDValue &Base) {
      return PPCLowering->SelectOptimalAddrMode(Parent, N, Disp, Base, *CurDAG,
                                                Align(16)) == PPC::AM_DQForm;
    }
 
    /// SelectDForm - Returns true if address N can be represented by
    /// the addressing mode of DForm instructions (a base register, plus a
    /// signed 16-bit immediate.
    bool SelectDForm(SDNode *Parent, SDValue N, SDValue &Disp, SDValue &Base) {
      return PPCLowering->SelectOptimalAddrMode(Parent, N, Disp, Base, *CurDAG,
                                                None) == PPC::AM_DForm;
    }
 
    /// SelectPCRelForm - Returns true if address N can be represented by
    /// PC-Relative addressing mode.
    bool SelectPCRelForm(SDNode *Parent, SDValue N, SDValue &Disp,
                         SDValue &Base) {
      return PPCLowering->SelectOptimalAddrMode(Parent, N, Disp, Base, *CurDAG,
                                                None) == PPC::AM_PCRel;
    }
 
    /// SelectPDForm - Returns true if address N can be represented by Prefixed
    /// DForm addressing mode (a base register, plus a signed 34-bit immediate.
    bool SelectPDForm(SDNode *Parent, SDValue N, SDValue &Disp, SDValue &Base) {
      return PPCLowering->SelectOptimalAddrMode(Parent, N, Disp, Base, *CurDAG,
                                                None) == PPC::AM_PrefixDForm;
    }
 
    /// SelectXForm - Returns true if address N can be represented by the
    /// addressing mode of XForm instructions (an indexed [r+r] operation).
    bool SelectXForm(SDNode *Parent, SDValue N, SDValue &Disp, SDValue &Base) {
      return PPCLowering->SelectOptimalAddrMode(Parent, N, Disp, Base, *CurDAG,
                                                None) == PPC::AM_XForm;
    }
 
    /// SelectForceXForm - Given the specified address, force it to be
    /// represented as an indexed [r+r] operation (an XForm instruction).
    bool SelectForceXForm(SDNode *Parent, SDValue N, SDValue &Disp,
                          SDValue &Base) {
      return PPCLowering->SelectForceXFormMode(N, Disp, Base, *CurDAG) ==
             PPC::AM_XForm;
    }
 
    /// SelectAddrIdx - Given the specified address, check to see if it can be
    /// represented as an indexed [r+r] operation.
    /// This is for xform instructions whose associated displacement form is D.
    /// The last parameter \p 0 means associated D form has no requirment for 16
    /// bit signed displacement.
    /// Returns false if it can be represented by [r+imm], which are preferred.
    bool SelectAddrIdx(SDValue N, SDValue &Base, SDValue &Index) {
      return PPCLowering->SelectAddressRegReg(N, Base, Index, *CurDAG, None);
    }
 
    /// SelectAddrIdx4 - Given the specified address, check to see if it can be
    /// represented as an indexed [r+r] operation.
    /// This is for xform instructions whose associated displacement form is DS.
    /// The last parameter \p 4 means associated DS form 16 bit signed
    /// displacement must be a multiple of 4.
    /// Returns false if it can be represented by [r+imm], which are preferred.
    bool SelectAddrIdxX4(SDValue N, SDValue &Base, SDValue &Index) {
      return PPCLowering->SelectAddressRegReg(N, Base, Index, *CurDAG,
                                              Align(4));
    }
 
    /// SelectAddrIdx16 - Given the specified address, check to see if it can be
    /// represented as an indexed [r+r] operation.
    /// This is for xform instructions whose associated displacement form is DQ.
    /// The last parameter \p 16 means associated DQ form 16 bit signed
    /// displacement must be a multiple of 16.
    /// Returns false if it can be represented by [r+imm], which are preferred.
    bool SelectAddrIdxX16(SDValue N, SDValue &Base, SDValue &Index) {
      return PPCLowering->SelectAddressRegReg(N, Base, Index, *CurDAG,
                                              Align(16));
    }
 
    /// SelectAddrIdxOnly - Given the specified address, force it to be
    /// represented as an indexed [r+r] operation.
    bool SelectAddrIdxOnly(SDValue N, SDValue &Base, SDValue &Index) {
      return PPCLowering->SelectAddressRegRegOnly(N, Base, Index, *CurDAG);
    }
 
    /// SelectAddrImm - Returns true if the address N can be represented by
    /// a base register plus a signed 16-bit displacement [r+imm].
    /// The last parameter \p 0 means D form has no requirment for 16 bit signed
    /// displacement.
    bool SelectAddrImm(SDValue N, SDValue &Disp,
                       SDValue &Base) {
      return PPCLowering->SelectAddressRegImm(N, Disp, Base, *CurDAG, None);
    }
 
    /// SelectAddrImmX4 - Returns true if the address N can be represented by
    /// a base register plus a signed 16-bit displacement that is a multiple of
    /// 4 (last parameter). Suitable for use by STD and friends.
    bool SelectAddrImmX4(SDValue N, SDValue &Disp, SDValue &Base) {
      return PPCLowering->SelectAddressRegImm(N, Disp, Base, *CurDAG, Align(4));
    }
 
    /// SelectAddrImmX16 - Returns true if the address N can be represented by
    /// a base register plus a signed 16-bit displacement that is a multiple of
    /// 16(last parameter). Suitable for use by STXV and friends.
    bool SelectAddrImmX16(SDValue N, SDValue &Disp, SDValue &Base) {
      return PPCLowering->SelectAddressRegImm(N, Disp, Base, *CurDAG,
                                              Align(16));
    }
 
    /// SelectAddrImmX34 - Returns true if the address N can be represented by
    /// a base register plus a signed 34-bit displacement. Suitable for use by
    /// PSTXVP and friends.
    bool SelectAddrImmX34(SDValue N, SDValue &Disp, SDValue &Base) {
      return PPCLowering->SelectAddressRegImm34(N, Disp, Base, *CurDAG);
    }
 
    // Select an address into a single register.
    bool SelectAddr(SDValue N, SDValue &Base) {
      Base = N;
      return true;
    }
 
    bool SelectAddrPCRel(SDValue N, SDValue &Base) {
      return PPCLowering->SelectAddressPCRel(N, Base);
    }
 
    /// SelectInlineAsmMemoryOperand - Implement addressing mode selection for
    /// inline asm expressions.  It is always correct to compute the value into
    /// a register.  The case of adding a (possibly relocatable) constant to a
    /// register can be improved, but it is wrong to substitute Reg+Reg for
    /// Reg in an asm, because the load or store opcode would have to change.
    bool SelectInlineAsmMemoryOperand(const SDValue &Op,
                                      unsigned ConstraintID,
                                      std::vector<SDValue> &OutOps) override {
      switch(ConstraintID) {
      default:
        errs() << "ConstraintID: " << ConstraintID << "\n";
        llvm_unreachable("Unexpected asm memory constraint");
      case InlineAsm::Constraint_es:
      case InlineAsm::Constraint_m:
      case InlineAsm::Constraint_o:
      case InlineAsm::Constraint_Q:
      case InlineAsm::Constraint_Z:
      case InlineAsm::Constraint_Zy:
        // We need to make sure that this one operand does not end up in r0
        // (because we might end up lowering this as 0(%op)).
        const TargetRegisterInfo *TRI = Subtarget->getRegisterInfo();
        const TargetRegisterClass *TRC = TRI->getPointerRegClass(*MF, /*Kind=*/1);
        SDLoc dl(Op);
        SDValue RC = CurDAG->getTargetConstant(TRC->getID(), dl, MVT::i32);
        SDValue NewOp =
          SDValue(CurDAG->getMachineNode(TargetOpcode::COPY_TO_REGCLASS,
                                         dl, Op.getValueType(),
                                         Op, RC), 0);
 
        OutOps.push_back(NewOp);
        return false;
      }
      return true;
    }
 
    StringRef getPassName() const override {
      return "PowerPC DAG->DAG Pattern Instruction Selection";
    }
 
// Include the pieces autogenerated from the target description.
#include "PPCGenDAGISel.inc"
 
private:
    bool trySETCC(SDNode *N);
    bool tryFoldSWTestBRCC(SDNode *N);
    bool trySelectLoopCountIntrinsic(SDNode *N);
    bool tryAsSingleRLDICL(SDNode *N);
    bool tryAsSingleRLDICR(SDNode *N);
    bool tryAsSingleRLWINM(SDNode *N);
    bool tryAsSingleRLWINM8(SDNode *N);
    bool tryAsSingleRLWIMI(SDNode *N);
    bool tryAsPairOfRLDICL(SDNode *N);
    bool tryAsSingleRLDIMI(SDNode *N);
 
    void PeepholePPC64();
    void PeepholePPC64ZExt();
    void PeepholeCROps();
 
    SDValue combineToCMPB(SDNode *N);
    void foldBoolExts(SDValue &Res, SDNode *&N);
 
    bool AllUsersSelectZero(SDNode *N);
    void SwapAllSelectUsers(SDNode *N);
 
    bool isOffsetMultipleOf(SDNode *N, unsigned Val) const;
    void transferMemOperands(SDNode *N, SDNode *Result);
  };
 
} // end anonymous namespace
 
/// getGlobalBaseReg - Output the instructions required to put the
/// base address to use for accessing globals into a register.
///
SDNode *PPCDAGToDAGISel::getGlobalBaseReg() {
  if (!GlobalBaseReg) {
    const TargetInstrInfo &TII = *Subtarget->getInstrInfo();
    // Insert the set of GlobalBaseReg into the first MBB of the function
    MachineBasicBlock &FirstMBB = MF->front();
    MachineBasicBlock::iterator MBBI = FirstMBB.begin();
    const Module *M = MF->getFunction().getParent();
    DebugLoc dl;
 
    if (PPCLowering->getPointerTy(CurDAG->getDataLayout()) == MVT::i32) {
      if (Subtarget->isTargetELF()) {
        GlobalBaseReg = PPC::R30;
        if (!Subtarget->isSecurePlt() &&
            M->getPICLevel() == PICLevel::SmallPIC) {
          BuildMI(FirstMBB, MBBI, dl, TII.get(PPC::MoveGOTtoLR));
          BuildMI(FirstMBB, MBBI, dl, TII.get(PPC::MFLR), GlobalBaseReg);
          MF->getInfo<PPCFunctionInfo>()->setUsesPICBase(true);
        } else {
          BuildMI(FirstMBB, MBBI, dl, TII.get(PPC::MovePCtoLR));
          BuildMI(FirstMBB, MBBI, dl, TII.get(PPC::MFLR), GlobalBaseReg);
          Register TempReg = RegInfo->createVirtualRegister(&PPC::GPRCRegClass);
          BuildMI(FirstMBB, MBBI, dl,
                  TII.get(PPC::UpdateGBR), GlobalBaseReg)
                  .addReg(TempReg, RegState::Define).addReg(GlobalBaseReg);
          MF->getInfo<PPCFunctionInfo>()->setUsesPICBase(true);
        }
      } else {
        GlobalBaseReg =
          RegInfo->createVirtualRegister(&PPC::GPRC_and_GPRC_NOR0RegClass);
        BuildMI(FirstMBB, MBBI, dl, TII.get(PPC::MovePCtoLR));
        BuildMI(FirstMBB, MBBI, dl, TII.get(PPC::MFLR), GlobalBaseReg);
      }
    } else {
      // We must ensure that this sequence is dominated by the prologue.
      // FIXME: This is a bit of a big hammer since we don't get the benefits
      // of shrink-wrapping whenever we emit this instruction. Considering
      // this is used in any function where we emit a jump table, this may be
      // a significant limitation. We should consider inserting this in the
      // block where it is used and then commoning this sequence up if it
      // appears in multiple places.
      // Note: on ISA 3.0 cores, we can use lnia (addpcis) instead of
      // MovePCtoLR8.
      MF->getInfo<PPCFunctionInfo>()->setShrinkWrapDisabled(true);
      GlobalBaseReg = RegInfo->createVirtualRegister(&PPC::G8RC_and_G8RC_NOX0RegClass);
      BuildMI(FirstMBB, MBBI, dl, TII.get(PPC::MovePCtoLR8));
      BuildMI(FirstMBB, MBBI, dl, TII.get(PPC::MFLR8), GlobalBaseReg);
    }
  }
  return CurDAG->getRegister(GlobalBaseReg,
                             PPCLowering->getPointerTy(CurDAG->getDataLayout()))
      .getNode();
}
 
// Check if a SDValue has the toc-data attribute.
static bool hasTocDataAttr(SDValue Val, unsigned PointerSize) {
  GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(Val);
  if (!GA)
    return false;
 
  const GlobalVariable *GV = dyn_cast_or_null<GlobalVariable>(GA->getGlobal());
  if (!GV)
    return false;
 
  if (!GV->hasAttribute("toc-data"))
    return false;
 
  // TODO: These asserts should be updated as more support for the toc data
  // transformation is added (struct support, etc.).
 
  assert(
      PointerSize >= GV->getAlign().valueOrOne().value() &&
      "GlobalVariables with an alignment requirement stricter than TOC entry "
      "size not supported by the toc data transformation.");
 
  Type *GVType = GV->getValueType();
 
  assert(GVType->isSized() && "A GlobalVariable's size must be known to be "
                              "supported by the toc data transformation.");
 
  if (GVType->isVectorTy())
    report_fatal_error("A GlobalVariable of Vector type is not currently "
                       "supported by the toc data transformation.");
 
  if (GVType->isArrayTy())
    report_fatal_error("A GlobalVariable of Array type is not currently "
                       "supported by the toc data transformation.");
 
  if (GVType->isStructTy())
    report_fatal_error("A GlobalVariable of Struct type is not currently "
                       "supported by the toc data transformation.");
 
  assert(GVType->getPrimitiveSizeInBits() <= PointerSize * 8 &&
         "A GlobalVariable with size larger than a TOC entry is not currently "
         "supported by the toc data transformation.");
 
  if (GV->hasLocalLinkage() || GV->hasPrivateLinkage())
    report_fatal_error("A GlobalVariable with private or local linkage is not "
                       "currently supported by the toc data transformation.");
 
  assert(!GV->hasCommonLinkage() &&
         "Tentative definitions cannot have the mapping class XMC_TD.");
 
  return true;
}
 
/// isInt32Immediate - This method tests to see if the node is a 32-bit constant
/// operand. If so Imm will receive the 32-bit value.
static bool isInt32Immediate(SDNode *N, unsigned &Imm) {
  if (N->getOpcode() == ISD::Constant && N->getValueType(0) == MVT::i32) {
    Imm = cast<ConstantSDNode>(N)->getZExtValue();
    return true;
  }
  return false;
}
 
/// isInt64Immediate - This method tests to see if the node is a 64-bit constant
/// operand.  If so Imm will receive the 64-bit value.
static bool isInt64Immediate(SDNode *N, uint64_t &Imm) {
  if (N->getOpcode() == ISD::Constant && N->getValueType(0) == MVT::i64) {
    Imm = cast<ConstantSDNode>(N)->getZExtValue();
    return true;
  }
  return false;
}
 
// isInt32Immediate - This method tests to see if a constant operand.
// If so Imm will receive the 32 bit value.
static bool isInt32Immediate(SDValue N, unsigned &Imm) {
  return isInt32Immediate(N.getNode(), Imm);
}
 
/// isInt64Immediate - This method tests to see if the value is a 64-bit
/// constant operand. If so Imm will receive the 64-bit value.
static bool isInt64Immediate(SDValue N, uint64_t &Imm) {
  return isInt64Immediate(N.getNode(), Imm);
}
 
static unsigned getBranchHint(unsigned PCC,
                              const FunctionLoweringInfo &FuncInfo,
                              const SDValue &DestMBB) {
  assert(isa<BasicBlockSDNode>(DestMBB));
 
  if (!FuncInfo.BPI) return PPC::BR_NO_HINT;
 
  const BasicBlock *BB = FuncInfo.MBB->getBasicBlock();
  const Instruction *BBTerm = BB->getTerminator();
 
  if (BBTerm->getNumSuccessors() != 2) return PPC::BR_NO_HINT;
 
  const BasicBlock *TBB = BBTerm->getSuccessor(0);
  const BasicBlock *FBB = BBTerm->getSuccessor(1);
 
  auto TProb = FuncInfo.BPI->getEdgeProbability(BB, TBB);
  auto FProb = FuncInfo.BPI->getEdgeProbability(BB, FBB);
 
  // We only want to handle cases which are easy to predict at static time, e.g.
  // C++ throw statement, that is very likely not taken, or calling never
  // returned function, e.g. stdlib exit(). So we set Threshold to filter
  // unwanted cases.
  //
  // Below is LLVM branch weight table, we only want to handle case 1, 2
  //
  // Case                  Taken:Nontaken  Example
  // 1. Unreachable        1048575:1       C++ throw, stdlib exit(),
  // 2. Invoke-terminating 1:1048575
  // 3. Coldblock          4:64            __builtin_expect
  // 4. Loop Branch        124:4           For loop
  // 5. PH/ZH/FPH          20:12
  const uint32_t Threshold = 10000;
 
  if (std::max(TProb, FProb) / Threshold < std::min(TProb, FProb))
    return PPC::BR_NO_HINT;
 
  LLVM_DEBUG(dbgs() << "Use branch hint for '" << FuncInfo.Fn->getName()
                    << "::" << BB->getName() << "'\n"
                    << " -> " << TBB->getName() << ": " << TProb << "\n"
                    << " -> " << FBB->getName() << ": " << FProb << "\n");
 
  const BasicBlockSDNode *BBDN = cast<BasicBlockSDNode>(DestMBB);
 
  // If Dest BasicBlock is False-BasicBlock (FBB), swap branch probabilities,
  // because we want 'TProb' stands for 'branch probability' to Dest BasicBlock
  if (BBDN->getBasicBlock()->getBasicBlock() != TBB)
    std::swap(TProb, FProb);
 
  return (TProb > FProb) ? PPC::BR_TAKEN_HINT : PPC::BR_NONTAKEN_HINT;
}
 
// isOpcWithIntImmediate - This method tests to see if the node is a specific
// opcode and that it has a immediate integer right operand.
// If so Imm will receive the 32 bit value.
static bool isOpcWithIntImmediate(SDNode *N, unsigned Opc, unsigned& Imm) {
  return N->getOpcode() == Opc
         && isInt32Immediate(N->getOperand(1).getNode(), Imm);
}
 
void PPCDAGToDAGISel::selectFrameIndex(SDNode *SN, SDNode *N, uint64_t Offset) {
  SDLoc dl(SN);
  int FI = cast<FrameIndexSDNode>(N)->getIndex();
  SDValue TFI = CurDAG->getTargetFrameIndex(FI, N->getValueType(0));
  unsigned Opc = N->getValueType(0) == MVT::i32 ? PPC::ADDI : PPC::ADDI8;
  if (SN->hasOneUse())
    CurDAG->SelectNodeTo(SN, Opc, N->getValueType(0), TFI,
                         getSmallIPtrImm(Offset, dl));
  else
    ReplaceNode(SN, CurDAG->getMachineNode(Opc, dl, N->getValueType(0), TFI,
                                           getSmallIPtrImm(Offset, dl)));
}
 
bool PPCDAGToDAGISel::isRotateAndMask(SDNode *N, unsigned Mask,
                                      bool isShiftMask, unsigned &SH,
                                      unsigned &MB, unsigned &ME) {
  // Don't even go down this path for i64, since different logic will be
  // necessary for rldicl/rldicr/rldimi.
  if (N->getValueType(0) != MVT::i32)
    return false;
 
  unsigned Shift  = 32;
  unsigned Indeterminant = ~0;  // bit mask marking indeterminant results
  unsigned Opcode = N->getOpcode();
  if (N->getNumOperands() != 2 ||
      !isInt32Immediate(N->getOperand(1).getNode(), Shift) || (Shift > 31))
    return false;
 
  if (Opcode == ISD::SHL) {
    // apply shift left to mask if it comes first
    if (isShiftMask) Mask = Mask << Shift;
    // determine which bits are made indeterminant by shift
    Indeterminant = ~(0xFFFFFFFFu << Shift);
  } else if (Opcode == ISD::SRL) {
    // apply shift right to mask if it comes first
    if (isShiftMask) Mask = Mask >> Shift;
    // determine which bits are made indeterminant by shift
    Indeterminant = ~(0xFFFFFFFFu >> Shift);
    // adjust for the left rotate
    Shift = 32 - Shift;
  } else if (Opcode == ISD::ROTL) {
    Indeterminant = 0;
  } else {
    return false;
  }
 
  // if the mask doesn't intersect any Indeterminant bits
  if (Mask && !(Mask & Indeterminant)) {
    SH = Shift & 31;
    // make sure the mask is still a mask (wrap arounds may not be)
    return isRunOfOnes(Mask, MB, ME);
  }
  return false;
}
 
bool PPCDAGToDAGISel::tryTLSXFormStore(StoreSDNode *ST) {
  SDValue Base = ST->getBasePtr();
  if (Base.getOpcode() != PPCISD::ADD_TLS)
    return false;
  SDValue Offset = ST->getOffset();
  if (!Offset.isUndef())
    return false;
  if (Base.getOperand(1).getOpcode() == PPCISD::TLS_LOCAL_EXEC_MAT_ADDR)
    return false;
 
  SDLoc dl(ST);
  EVT MemVT = ST->getMemoryVT();
  EVT RegVT = ST->getValue().getValueType();
 
  unsigned Opcode;
  switch (MemVT.getSimpleVT().SimpleTy) {
    default:
      return false;
    case MVT::i8: {
      Opcode = (RegVT == MVT::i32) ? PPC::STBXTLS_32 : PPC::STBXTLS;
      break;
    }
    case MVT::i16: {
      Opcode = (RegVT == MVT::i32) ? PPC::STHXTLS_32 : PPC::STHXTLS;
      break;
    }
    case MVT::i32: {
      Opcode = (RegVT == MVT::i32) ? PPC::STWXTLS_32 : PPC::STWXTLS;
      break;
    }
    case MVT::i64: {
      Opcode = PPC::STDXTLS;
      break;
    }
  }
  SDValue Chain = ST->getChain();
  SDVTList VTs = ST->getVTList();
  SDValue Ops[] = {ST->getValue(), Base.getOperand(0), Base.getOperand(1),
                   Chain};
  SDNode *MN = CurDAG->getMachineNode(Opcode, dl, VTs, Ops);
  transferMemOperands(ST, MN);
  ReplaceNode(ST, MN);
  return true;
}
 
bool PPCDAGToDAGISel::tryTLSXFormLoad(LoadSDNode *LD) {
  SDValue Base = LD->getBasePtr();
  if (Base.getOpcode() != PPCISD::ADD_TLS)
    return false;
  SDValue Offset = LD->getOffset();
  if (!Offset.isUndef())
    return false;
  if (Base.getOperand(1).getOpcode() == PPCISD::TLS_LOCAL_EXEC_MAT_ADDR)
    return false;
 
  SDLoc dl(LD);
  EVT MemVT = LD->getMemoryVT();
  EVT RegVT = LD->getValueType(0);
  unsigned Opcode;
  switch (MemVT.getSimpleVT().SimpleTy) {
    default:
      return false;
    case MVT::i8: {
      Opcode = (RegVT == MVT::i32) ? PPC::LBZXTLS_32 : PPC::LBZXTLS;
      break;
    }
    case MVT::i16: {
      Opcode = (RegVT == MVT::i32) ? PPC::LHZXTLS_32 : PPC::LHZXTLS;
      break;
    }
    case MVT::i32: {
      Opcode = (RegVT == MVT::i32) ? PPC::LWZXTLS_32 : PPC::LWZXTLS;
      break;
    }
    case MVT::i64: {
      Opcode = PPC::LDXTLS;
      break;
    }
  }
  SDValue Chain = LD->getChain();
  SDVTList VTs = LD->getVTList();
  SDValue Ops[] = {Base.getOperand(0), Base.getOperand(1), Chain};
  SDNode *MN = CurDAG->getMachineNode(Opcode, dl, VTs, Ops);
  transferMemOperands(LD, MN);
  ReplaceNode(LD, MN);
  return true;
}
 
/// Turn an or of two masked values into the rotate left word immediate then
/// mask insert (rlwimi) instruction.
bool PPCDAGToDAGISel::tryBitfieldInsert(SDNode *N) {
  SDValue Op0 = N->getOperand(0);
  SDValue Op1 = N->getOperand(1);
  SDLoc dl(N);
 
  KnownBits LKnown = CurDAG->computeKnownBits(Op0);
  KnownBits RKnown = CurDAG->computeKnownBits(Op1);
 
  unsigned TargetMask = LKnown.Zero.getZExtValue();
  unsigned InsertMask = RKnown.Zero.getZExtValue();
 
  if ((TargetMask | InsertMask) == 0xFFFFFFFF) {
    unsigned Op0Opc = Op0.getOpcode();
    unsigned Op1Opc = Op1.getOpcode();
    unsigned Value, SH = 0;
    TargetMask = ~TargetMask;
    InsertMask = ~InsertMask;
 
    // If the LHS has a foldable shift and the RHS does not, then swap it to the
    // RHS so that we can fold the shift into the insert.
    if (Op0Opc == ISD::AND && Op1Opc == ISD::AND) {
      if (Op0.getOperand(0).getOpcode() == ISD::SHL ||
          Op0.getOperand(0).getOpcode() == ISD::SRL) {
        if (Op1.getOperand(0).getOpcode() != ISD::SHL &&
            Op1.getOperand(0).getOpcode() != ISD::SRL) {
          std::swap(Op0, Op1);
          std::swap(Op0Opc, Op1Opc);
          std::swap(TargetMask, InsertMask);
        }
      }
    } else if (Op0Opc == ISD::SHL || Op0Opc == ISD::SRL) {
      if (Op1Opc == ISD::AND && Op1.getOperand(0).getOpcode() != ISD::SHL &&
          Op1.getOperand(0).getOpcode() != ISD::SRL) {
        std::swap(Op0, Op1);
        std::swap(Op0Opc, Op1Opc);
        std::swap(TargetMask, InsertMask);
      }
    }
 
    unsigned MB, ME;
    if (isRunOfOnes(InsertMask, MB, ME)) {
      if ((Op1Opc == ISD::SHL || Op1Opc == ISD::SRL) &&
          isInt32Immediate(Op1.getOperand(1), Value)) {
        Op1 = Op1.getOperand(0);
        SH  = (Op1Opc == ISD::SHL) ? Value : 32 - Value;
      }
      if (Op1Opc == ISD::AND) {
       // The AND mask might not be a constant, and we need to make sure that
       // if we're going to fold the masking with the insert, all bits not
       // know to be zero in the mask are known to be one.
        KnownBits MKnown = CurDAG->computeKnownBits(Op1.getOperand(1));
        bool CanFoldMask = InsertMask == MKnown.One.getZExtValue();
 
        unsigned SHOpc = Op1.getOperand(0).getOpcode();
        if ((SHOpc == ISD::SHL || SHOpc == ISD::SRL) && CanFoldMask &&
            isInt32Immediate(Op1.getOperand(0).getOperand(1), Value)) {
          // Note that Value must be in range here (less than 32) because
          // otherwise there would not be any bits set in InsertMask.
          Op1 = Op1.getOperand(0).getOperand(0);
          SH  = (SHOpc == ISD::SHL) ? Value : 32 - Value;
        }
      }
 
      SH &= 31;
      SDValue Ops[] = { Op0, Op1, getI32Imm(SH, dl), getI32Imm(MB, dl),
                          getI32Imm(ME, dl) };
      ReplaceNode(N, CurDAG->getMachineNode(PPC::RLWIMI, dl, MVT::i32, Ops));
      return true;
    }
  }
  return false;
}
 
static unsigned allUsesTruncate(SelectionDAG *CurDAG, SDNode *N) {
  unsigned MaxTruncation = 0;
  // Cannot use range-based for loop here as we need the actual use (i.e. we
  // need the operand number corresponding to the use). A range-based for
  // will unbox the use and provide an SDNode*.
  for (SDNode::use_iterator Use = N->use_begin(), UseEnd = N->use_end();
       Use != UseEnd; ++Use) {
    unsigned Opc =
      Use->isMachineOpcode() ? Use->getMachineOpcode() : Use->getOpcode();
    switch (Opc) {
    default: return 0;
    case ISD::TRUNCATE:
      if (Use->isMachineOpcode())
        return 0;
      MaxTruncation =
        std::max(MaxTruncation, (unsigned)Use->getValueType(0).getSizeInBits());
      continue;
    case ISD::STORE: {
      if (Use->isMachineOpcode())
        return 0;
      StoreSDNode *STN = cast<StoreSDNode>(*Use);
      unsigned MemVTSize = STN->getMemoryVT().getSizeInBits();
      if (MemVTSize == 64 || Use.getOperandNo() != 0)
        return 0;
      MaxTruncation = std::max(MaxTruncation, MemVTSize);
      continue;
    }
    case PPC::STW8:
    case PPC::STWX8:
    case PPC::STWU8:
    case PPC::STWUX8:
      if (Use.getOperandNo() != 0)
        return 0;
      MaxTruncation = std::max(MaxTruncation, 32u);
      continue;
    case PPC::STH8:
    case PPC::STHX8:
    case PPC::STHU8:
    case PPC::STHUX8:
      if (Use.getOperandNo() != 0)
        return 0;
      MaxTruncation = std::max(MaxTruncation, 16u);
      continue;
    case PPC::STB8:
    case PPC::STBX8:
    case PPC::STBU8:
    case PPC::STBUX8:
      if (Use.getOperandNo() != 0)
        return 0;
      MaxTruncation = std::max(MaxTruncation, 8u);
      continue;
    }
  }
  return MaxTruncation;
}
 
// For any 32 < Num < 64, check if the Imm contains at least Num consecutive
// zeros and return the number of bits by the left of these consecutive zeros.
static int findContiguousZerosAtLeast(uint64_t Imm, unsigned Num) {
  unsigned HiTZ = countTrailingZeros<uint32_t>(Hi_32(Imm));
  unsigned LoLZ = countLeadingZeros<uint32_t>(Lo_32(Imm));
  if ((HiTZ + LoLZ) >= Num)
    return (32 + HiTZ);
  return 0;
}
 
// Direct materialization of 64-bit constants by enumerated patterns.
static SDNode *selectI64ImmDirect(SelectionDAG *CurDAG, const SDLoc &dl,
                                  uint64_t Imm, unsigned &InstCnt) {
  unsigned TZ = countTrailingZeros<uint64_t>(Imm);
  unsigned LZ = countLeadingZeros<uint64_t>(Imm);
  unsigned TO = countTrailingOnes<uint64_t>(Imm);
  unsigned LO = countLeadingOnes<uint64_t>(Imm);
  unsigned Hi32 = Hi_32(Imm);
  unsigned Lo32 = Lo_32(Imm);
  SDNode *Result = nullptr;
  unsigned Shift = 0;
 
  auto getI32Imm = [CurDAG, dl](unsigned Imm) {
    return CurDAG->getTargetConstant(Imm, dl, MVT::i32);
  };
 
  // Following patterns use 1 instructions to materialize the Imm.
  InstCnt = 1;
  // 1-1) Patterns : {zeros}{15-bit valve}
  //                 {ones}{15-bit valve}
  if (isInt<16>(Imm)) {
    SDValue SDImm = CurDAG->getTargetConstant(Imm, dl, MVT::i64);
    return CurDAG->getMachineNode(PPC::LI8, dl, MVT::i64, SDImm);
  }
  // 1-2) Patterns : {zeros}{15-bit valve}{16 zeros}
  //                 {ones}{15-bit valve}{16 zeros}
  if (TZ > 15 && (LZ > 32 || LO > 32))
    return CurDAG->getMachineNode(PPC::LIS8, dl, MVT::i64,
                                  getI32Imm((Imm >> 16) & 0xffff));
 
  // Following patterns use 2 instructions to materialize the Imm.
  InstCnt = 2;
  assert(LZ < 64 && "Unexpected leading zeros here.");
  // Count of ones follwing the leading zeros.
  unsigned FO = countLeadingOnes<uint64_t>(Imm << LZ);
  // 2-1) Patterns : {zeros}{31-bit value}
  //                 {ones}{31-bit value}
  if (isInt<32>(Imm)) {
    uint64_t ImmHi16 = (Imm >> 16) & 0xffff;
    unsigned Opcode = ImmHi16 ? PPC::LIS8 : PPC::LI8;
    Result = CurDAG->getMachineNode(Opcode, dl, MVT::i64, getI32Imm(ImmHi16));
    return CurDAG->getMachineNode(PPC::ORI8, dl, MVT::i64, SDValue(Result, 0),
                                  getI32Imm(Imm & 0xffff));
  }
  // 2-2) Patterns : {zeros}{ones}{15-bit value}{zeros}
  //                 {zeros}{15-bit value}{zeros}
  //                 {zeros}{ones}{15-bit value}
  //                 {ones}{15-bit value}{zeros}
  // We can take advantage of LI's sign-extension semantics to generate leading
  // ones, and then use RLDIC to mask off the ones in both sides after rotation.
  if ((LZ + FO + TZ) > 48) {
    Result = CurDAG->getMachineNode(PPC::LI8, dl, MVT::i64,
                                    getI32Imm((Imm >> TZ) & 0xffff));
    return CurDAG->getMachineNode(PPC::RLDIC, dl, MVT::i64, SDValue(Result, 0),
                                  getI32Imm(TZ), getI32Imm(LZ));
  }
  // 2-3) Pattern : {zeros}{15-bit value}{ones}
  // Shift right the Imm by (48 - LZ) bits to construct a negtive 16 bits value,
  // therefore we can take advantage of LI's sign-extension semantics, and then
  // mask them off after rotation.
  //
  // +--LZ--||-15-bit-||--TO--+     +-------------|--16-bit--+
  // |00000001bbbbbbbbb1111111| ->  |00000000000001bbbbbbbbb1|
  // +------------------------+     +------------------------+
  // 63                      0      63                      0
  //          Imm                   (Imm >> (48 - LZ) & 0xffff)
  // +----sext-----|--16-bit--+     +clear-|-----------------+
  // |11111111111111bbbbbbbbb1| ->  |00000001bbbbbbbbb1111111|
  // +------------------------+     +------------------------+
  // 63                      0      63                      0
  // LI8: sext many leading zeros   RLDICL: rotate left (48 - LZ), clear left LZ
  if ((LZ + TO) > 48) {
    // Since the immediates with (LZ > 32) have been handled by previous
    // patterns, here we have (LZ <= 32) to make sure we will not shift right
    // the Imm by a negative value.
    assert(LZ <= 32 && "Unexpected shift value.");
    Result = CurDAG->getMachineNode(PPC::LI8, dl, MVT::i64,
                                    getI32Imm((Imm >> (48 - LZ) & 0xffff)));
    return CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, SDValue(Result, 0),
                                  getI32Imm(48 - LZ), getI32Imm(LZ));
  }
  // 2-4) Patterns : {zeros}{ones}{15-bit value}{ones}
  //                 {ones}{15-bit value}{ones}
  // We can take advantage of LI's sign-extension semantics to generate leading
  // ones, and then use RLDICL to mask off the ones in left sides (if required)
  // after rotation.
  //
  // +-LZ-FO||-15-bit-||--TO--+     +-------------|--16-bit--+
  // |00011110bbbbbbbbb1111111| ->  |000000000011110bbbbbbbbb|
  // +------------------------+     +------------------------+
  // 63                      0      63                      0
  //            Imm                    (Imm >> TO) & 0xffff
  // +----sext-----|--16-bit--+     +LZ|---------------------+
  // |111111111111110bbbbbbbbb| ->  |00011110bbbbbbbbb1111111|
  // +------------------------+     +------------------------+
  // 63                      0      63                      0
  // LI8: sext many leading zeros   RLDICL: rotate left TO, clear left LZ
  if ((LZ + FO + TO) > 48) {
    Result = CurDAG->getMachineNode(PPC::LI8, dl, MVT::i64,
                                    getI32Imm((Imm >> TO) & 0xffff));
    return CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, SDValue(Result, 0),
                                  getI32Imm(TO), getI32Imm(LZ));
  }
  // 2-5) Pattern : {32 zeros}{****}{0}{15-bit value}
  // If Hi32 is zero and the Lo16(in Lo32) can be presented as a positive 16 bit
  // value, we can use LI for Lo16 without generating leading ones then add the
  // Hi16(in Lo32).
  if (LZ == 32 && ((Lo32 & 0x8000) == 0)) {
    Result = CurDAG->getMachineNode(PPC::LI8, dl, MVT::i64,
                                    getI32Imm(Lo32 & 0xffff));
    return CurDAG->getMachineNode(PPC::ORIS8, dl, MVT::i64, SDValue(Result, 0),
                                  getI32Imm(Lo32 >> 16));
  }
  // 2-6) Patterns : {******}{49 zeros}{******}
  //                 {******}{49 ones}{******}
  // If the Imm contains 49 consecutive zeros/ones, it means that a total of 15
  // bits remain on both sides. Rotate right the Imm to construct an int<16>
  // value, use LI for int<16> value and then use RLDICL without mask to rotate
  // it back.
  //
  // 1) findContiguousZerosAtLeast(Imm, 49)
  // +------|--zeros-|------+     +---ones--||---15 bit--+
  // |bbbbbb0000000000aaaaaa| ->  |0000000000aaaaaabbbbbb|
  // +----------------------+     +----------------------+
  // 63                    0      63                    0
  //
  // 2) findContiguousZerosAtLeast(~Imm, 49)
  // +------|--ones--|------+     +---ones--||---15 bit--+
  // |bbbbbb1111111111aaaaaa| ->  |1111111111aaaaaabbbbbb|
  // +----------------------+     +----------------------+
  // 63                    0      63                    0
  if ((Shift = findContiguousZerosAtLeast(Imm, 49)) ||
      (Shift = findContiguousZerosAtLeast(~Imm, 49))) {
    uint64_t RotImm = APInt(64, Imm).rotr(Shift).getZExtValue();
    Result = CurDAG->getMachineNode(PPC::LI8, dl, MVT::i64,
                                    getI32Imm(RotImm & 0xffff));
    return CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, SDValue(Result, 0),
                                  getI32Imm(Shift), getI32Imm(0));
  }
 
  // Following patterns use 3 instructions to materialize the Imm.
  InstCnt = 3;
  // 3-1) Patterns : {zeros}{ones}{31-bit value}{zeros}
  //                 {zeros}{31-bit value}{zeros}
  //                 {zeros}{ones}{31-bit value}
  //                 {ones}{31-bit value}{zeros}
  // We can take advantage of LIS's sign-extension semantics to generate leading
  // ones, add the remaining bits with ORI, and then use RLDIC to mask off the
  // ones in both sides after rotation.
  if ((LZ + FO + TZ) > 32) {
    uint64_t ImmHi16 = (Imm >> (TZ + 16)) & 0xffff;
    unsigned Opcode = ImmHi16 ? PPC::LIS8 : PPC::LI8;
    Result = CurDAG->getMachineNode(Opcode, dl, MVT::i64, getI32Imm(ImmHi16));
    Result = CurDAG->getMachineNode(PPC::ORI8, dl, MVT::i64, SDValue(Result, 0),
                                    getI32Imm((Imm >> TZ) & 0xffff));
    return CurDAG->getMachineNode(PPC::RLDIC, dl, MVT::i64, SDValue(Result, 0),
                                  getI32Imm(TZ), getI32Imm(LZ));
  }
  // 3-2) Pattern : {zeros}{31-bit value}{ones}
  // Shift right the Imm by (32 - LZ) bits to construct a negtive 32 bits value,
  // therefore we can take advantage of LIS's sign-extension semantics, add
  // the remaining bits with ORI, and then mask them off after rotation.
  // This is similar to Pattern 2-3, please refer to the diagram there.
  if ((LZ + TO) > 32) {
    // Since the immediates with (LZ > 32) have been handled by previous
    // patterns, here we have (LZ <= 32) to make sure we will not shift right
    // the Imm by a negative value.
    assert(LZ <= 32 && "Unexpected shift value.");
    Result = CurDAG->getMachineNode(PPC::LIS8, dl, MVT::i64,
                                    getI32Imm((Imm >> (48 - LZ)) & 0xffff));
    Result = CurDAG->getMachineNode(PPC::ORI8, dl, MVT::i64, SDValue(Result, 0),
                                    getI32Imm((Imm >> (32 - LZ)) & 0xffff));
    return CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, SDValue(Result, 0),
                                  getI32Imm(32 - LZ), getI32Imm(LZ));
  }
  // 3-3) Patterns : {zeros}{ones}{31-bit value}{ones}
  //                 {ones}{31-bit value}{ones}
  // We can take advantage of LIS's sign-extension semantics to generate leading
  // ones, add the remaining bits with ORI, and then use RLDICL to mask off the
  // ones in left sides (if required) after rotation.
  // This is similar to Pattern 2-4, please refer to the diagram there.
  if ((LZ + FO + TO) > 32) {
    Result = CurDAG->getMachineNode(PPC::LIS8, dl, MVT::i64,
                                    getI32Imm((Imm >> (TO + 16)) & 0xffff));
    Result = CurDAG->getMachineNode(PPC::ORI8, dl, MVT::i64, SDValue(Result, 0),
                                    getI32Imm((Imm >> TO) & 0xffff));
    return CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, SDValue(Result, 0),
                                  getI32Imm(TO), getI32Imm(LZ));
  }
  // 3-4) Patterns : High word == Low word
  if (Hi32 == Lo32) {
    // Handle the first 32 bits.
    uint64_t ImmHi16 = (Lo32 >> 16) & 0xffff;
    unsigned Opcode = ImmHi16 ? PPC::LIS8 : PPC::LI8;
    Result = CurDAG->getMachineNode(Opcode, dl, MVT::i64, getI32Imm(ImmHi16));
    Result = CurDAG->getMachineNode(PPC::ORI8, dl, MVT::i64, SDValue(Result, 0),
                                    getI32Imm(Lo32 & 0xffff));
    // Use rldimi to insert the Low word into High word.
    SDValue Ops[] = {SDValue(Result, 0), SDValue(Result, 0), getI32Imm(32),
                     getI32Imm(0)};
    return CurDAG->getMachineNode(PPC::RLDIMI, dl, MVT::i64, Ops);
  }
  // 3-5) Patterns : {******}{33 zeros}{******}
  //                 {******}{33 ones}{******}
  // If the Imm contains 33 consecutive zeros/ones, it means that a total of 31
  // bits remain on both sides. Rotate right the Imm to construct an int<32>
  // value, use LIS + ORI for int<32> value and then use RLDICL without mask to
  // rotate it back.
  // This is similar to Pattern 2-6, please refer to the diagram there.
  if ((Shift = findContiguousZerosAtLeast(Imm, 33)) ||
      (Shift = findContiguousZerosAtLeast(~Imm, 33))) {
    uint64_t RotImm = APInt(64, Imm).rotr(Shift).getZExtValue();
    uint64_t ImmHi16 = (RotImm >> 16) & 0xffff;
    unsigned Opcode = ImmHi16 ? PPC::LIS8 : PPC::LI8;
    Result = CurDAG->getMachineNode(Opcode, dl, MVT::i64, getI32Imm(ImmHi16));
    Result = CurDAG->getMachineNode(PPC::ORI8, dl, MVT::i64, SDValue(Result, 0),
                                    getI32Imm(RotImm & 0xffff));
    return CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, SDValue(Result, 0),
                                  getI32Imm(Shift), getI32Imm(0));
  }
 
  InstCnt = 0;
  return nullptr;
}
 
// Try to select instructions to generate a 64 bit immediate using prefix as
// well as non prefix instructions. The function will return the SDNode
// to materialize that constant or it will return nullptr if it does not
// find one. The variable InstCnt is set to the number of instructions that
// were selected.
static SDNode *selectI64ImmDirectPrefix(SelectionDAG *CurDAG, const SDLoc &dl,
                                        uint64_t Imm, unsigned &InstCnt) {
  unsigned TZ = countTrailingZeros<uint64_t>(Imm);
  unsigned LZ = countLeadingZeros<uint64_t>(Imm);
  unsigned TO = countTrailingOnes<uint64_t>(Imm);
  unsigned FO = countLeadingOnes<uint64_t>(LZ == 64 ? 0 : (Imm << LZ));
  unsigned Hi32 = Hi_32(Imm);
  unsigned Lo32 = Lo_32(Imm);
 
  auto getI32Imm = [CurDAG, dl](unsigned Imm) {
    return CurDAG->getTargetConstant(Imm, dl, MVT::i32);
  };
 
  auto getI64Imm = [CurDAG, dl](uint64_t Imm) {
    return CurDAG->getTargetConstant(Imm, dl, MVT::i64);
  };
 
  // Following patterns use 1 instruction to materialize Imm.
  InstCnt = 1;
 
  // The pli instruction can materialize up to 34 bits directly.
  // If a constant fits within 34-bits, emit the pli instruction here directly.
  if (isInt<34>(Imm))
    return CurDAG->getMachineNode(PPC::PLI8, dl, MVT::i64,
                                  CurDAG->getTargetConstant(Imm, dl, MVT::i64));
 
  // Require at least two instructions.
  InstCnt = 2;
  SDNode *Result = nullptr;
  // Patterns : {zeros}{ones}{33-bit value}{zeros}
  //            {zeros}{33-bit value}{zeros}
  //            {zeros}{ones}{33-bit value}
  //            {ones}{33-bit value}{zeros}
  // We can take advantage of PLI's sign-extension semantics to generate leading
  // ones, and then use RLDIC to mask off the ones on both sides after rotation.
  if ((LZ + FO + TZ) > 30) {
    APInt SignedInt34 = APInt(34, (Imm >> TZ) & 0x3ffffffff);
    APInt Extended = SignedInt34.sext(64);
    Result = CurDAG->getMachineNode(PPC::PLI8, dl, MVT::i64,
                                    getI64Imm(*Extended.getRawData()));
    return CurDAG->getMachineNode(PPC::RLDIC, dl, MVT::i64, SDValue(Result, 0),
                                  getI32Imm(TZ), getI32Imm(LZ));
  }
  // Pattern : {zeros}{33-bit value}{ones}
  // Shift right the Imm by (30 - LZ) bits to construct a negative 34 bit value,
  // therefore we can take advantage of PLI's sign-extension semantics, and then
  // mask them off after rotation.
  //
  // +--LZ--||-33-bit-||--TO--+     +-------------|--34-bit--+
  // |00000001bbbbbbbbb1111111| ->  |00000000000001bbbbbbbbb1|
  // +------------------------+     +------------------------+
  // 63                      0      63                      0
  //
  // +----sext-----|--34-bit--+     +clear-|-----------------+
  // |11111111111111bbbbbbbbb1| ->  |00000001bbbbbbbbb1111111|
  // +------------------------+     +------------------------+
  // 63                      0      63                      0
  if ((LZ + TO) > 30) {
    APInt SignedInt34 = APInt(34, (Imm >> (30 - LZ)) & 0x3ffffffff);
    APInt Extended = SignedInt34.sext(64);
    Result = CurDAG->getMachineNode(PPC::PLI8, dl, MVT::i64,
                                    getI64Imm(*Extended.getRawData()));
    return CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, SDValue(Result, 0),
                                  getI32Imm(30 - LZ), getI32Imm(LZ));
  }
  // Patterns : {zeros}{ones}{33-bit value}{ones}
  //            {ones}{33-bit value}{ones}
  // Similar to LI we can take advantage of PLI's sign-extension semantics to
  // generate leading ones, and then use RLDICL to mask off the ones in left
  // sides (if required) after rotation.
  if ((LZ + FO + TO) > 30) {
    APInt SignedInt34 = APInt(34, (Imm >> TO) & 0x3ffffffff);
    APInt Extended = SignedInt34.sext(64);
    Result = CurDAG->getMachineNode(PPC::PLI8, dl, MVT::i64,
                                    getI64Imm(*Extended.getRawData()));
    return CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, SDValue(Result, 0),
                                  getI32Imm(TO), getI32Imm(LZ));
  }
  // Patterns : {******}{31 zeros}{******}
  //          : {******}{31 ones}{******}
  // If Imm contains 31 consecutive zeros/ones then the remaining bit count
  // is 33. Rotate right the Imm to construct a int<33> value, we can use PLI
  // for the int<33> value and then use RLDICL without a mask to rotate it back.
  //
  // +------|--ones--|------+     +---ones--||---33 bit--+
  // |bbbbbb1111111111aaaaaa| ->  |1111111111aaaaaabbbbbb|
  // +----------------------+     +----------------------+
  // 63                    0      63                    0
  for (unsigned Shift = 0; Shift < 63; ++Shift) {
    uint64_t RotImm = APInt(64, Imm).rotr(Shift).getZExtValue();
    if (isInt<34>(RotImm)) {
      Result =
          CurDAG->getMachineNode(PPC::PLI8, dl, MVT::i64, getI64Imm(RotImm));
      return CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64,
                                    SDValue(Result, 0), getI32Imm(Shift),
                                    getI32Imm(0));
    }
  }
 
  // Patterns : High word == Low word
  // This is basically a splat of a 32 bit immediate.
  if (Hi32 == Lo32) {
    Result = CurDAG->getMachineNode(PPC::PLI8, dl, MVT::i64, getI64Imm(Hi32));
    SDValue Ops[] = {SDValue(Result, 0), SDValue(Result, 0), getI32Imm(32),
                     getI32Imm(0)};
    return CurDAG->getMachineNode(PPC::RLDIMI, dl, MVT::i64, Ops);
  }
 
  InstCnt = 3;
  // Catch-all
  // This pattern can form any 64 bit immediate in 3 instructions.
  SDNode *ResultHi =
      CurDAG->getMachineNode(PPC::PLI8, dl, MVT::i64, getI64Imm(Hi32));
  SDNode *ResultLo =
      CurDAG->getMachineNode(PPC::PLI8, dl, MVT::i64, getI64Imm(Lo32));
  SDValue Ops[] = {SDValue(ResultLo, 0), SDValue(ResultHi, 0), getI32Imm(32),
                   getI32Imm(0)};
  return CurDAG->getMachineNode(PPC::RLDIMI, dl, MVT::i64, Ops);
}
 
static SDNode *selectI64Imm(SelectionDAG *CurDAG, const SDLoc &dl, uint64_t Imm,
                            unsigned *InstCnt = nullptr) {
  unsigned InstCntDirect = 0;
  // No more than 3 instructions is used if we can select the i64 immediate
  // directly.
  SDNode *Result = selectI64ImmDirect(CurDAG, dl, Imm, InstCntDirect);
 
  const PPCSubtarget &Subtarget =
      CurDAG->getMachineFunction().getSubtarget<PPCSubtarget>();
 
  // If we have prefixed instructions and there is a chance we can
  // materialize the constant with fewer prefixed instructions than
  // non-prefixed, try that.
  if (Subtarget.hasPrefixInstrs() && InstCntDirect != 1) {
    unsigned InstCntDirectP = 0;
    SDNode *ResultP = selectI64ImmDirectPrefix(CurDAG, dl, Imm, InstCntDirectP);
    // Use the prefix case in either of two cases:
    // 1) We have no result from the non-prefix case to use.
    // 2) The non-prefix case uses more instructions than the prefix case.
    // If the prefix and non-prefix cases use the same number of instructions
    // we will prefer the non-prefix case.
    if (ResultP && (!Result || InstCntDirectP < InstCntDirect)) {
      if (InstCnt)
        *InstCnt = InstCntDirectP;
      return ResultP;
    }
  }
 
  if (Result) {
    if (InstCnt)
      *InstCnt = InstCntDirect;
    return Result;
  }
  auto getI32Imm = [CurDAG, dl](unsigned Imm) {
    return CurDAG->getTargetConstant(Imm, dl, MVT::i32);
  };
  // Handle the upper 32 bit value.
  Result =
      selectI64ImmDirect(CurDAG, dl, Imm & 0xffffffff00000000, InstCntDirect);
  // Add in the last bits as required.
  if (uint32_t Hi16 = (Lo_32(Imm) >> 16) & 0xffff) {
    Result = CurDAG->getMachineNode(PPC::ORIS8, dl, MVT::i64,
                                    SDValue(Result, 0), getI32Imm(Hi16));
    ++InstCntDirect;
  }
  if (uint32_t Lo16 = Lo_32(Imm) & 0xffff) {
    Result = CurDAG->getMachineNode(PPC::ORI8, dl, MVT::i64, SDValue(Result, 0),
                                    getI32Imm(Lo16));
    ++InstCntDirect;
  }
  if (InstCnt)
    *InstCnt = InstCntDirect;
  return Result;
}
 
// Select a 64-bit constant.
static SDNode *selectI64Imm(SelectionDAG *CurDAG, SDNode *N) {
  SDLoc dl(N);
 
  // Get 64 bit value.
  int64_t Imm = cast<ConstantSDNode>(N)->getZExtValue();
  if (unsigned MinSize = allUsesTruncate(CurDAG, N)) {
    uint64_t SextImm = SignExtend64(Imm, MinSize);
    SDValue SDImm = CurDAG->getTargetConstant(SextImm, dl, MVT::i64);
    if (isInt<16>(SextImm))
      return CurDAG->getMachineNode(PPC::LI8, dl, MVT::i64, SDImm);
  }
  return selectI64Imm(CurDAG, dl, Imm);
}
 
namespace {
 
class BitPermutationSelector {
  struct ValueBit {
    SDValue V;
 
    // The bit number in the value, using a convention where bit 0 is the
    // lowest-order bit.
    unsigned Idx;
 
    // ConstZero means a bit we need to mask off.
    // Variable is a bit comes from an input variable.
    // VariableKnownToBeZero is also a bit comes from an input variable,
    // but it is known to be already zero. So we do not need to mask them.
    enum Kind {
      ConstZero,
      Variable,
      VariableKnownToBeZero
    } K;
 
    ValueBit(SDValue V, unsigned I, Kind K = Variable)
      : V(V), Idx(I), K(K) {}
    ValueBit(Kind K = Variable) : Idx(UINT32_MAX), K(K) {}
 
    bool isZero() const {
      return K == ConstZero || K == VariableKnownToBeZero;
    }
 
    bool hasValue() const {
      return K == Variable || K == VariableKnownToBeZero;
    }
 
    SDValue getValue() const {
      assert(hasValue() && "Cannot get the value of a constant bit");
      return V;
    }
 
    unsigned getValueBitIndex() const {
      assert(hasValue() && "Cannot get the value bit index of a constant bit");
      return Idx;
    }
  };
 
  // A bit group has the same underlying value and the same rotate factor.
  struct BitGroup {
    SDValue V;
    unsigned RLAmt;
    unsigned StartIdx, EndIdx;
 
    // This rotation amount assumes that the lower 32 bits of the quantity are
    // replicated in the high 32 bits by the rotation operator (which is done
    // by rlwinm and friends in 64-bit mode).
    bool Repl32;
    // Did converting to Repl32 == true change the rotation factor? If it did,
    // it decreased it by 32.
    bool Repl32CR;
    // Was this group coalesced after setting Repl32 to true?
    bool Repl32Coalesced;
 
    BitGroup(SDValue V, unsigned R, unsigned S, unsigned E)
      : V(V), RLAmt(R), StartIdx(S), EndIdx(E), Repl32(false), Repl32CR(false),
        Repl32Coalesced(false) {
      LLVM_DEBUG(dbgs() << "\tbit group for " << V.getNode() << " RLAmt = " << R
                        << " [" << S << ", " << E << "]\n");
    }
  };
 
  // Information on each (Value, RLAmt) pair (like the number of groups
  // associated with each) used to choose the lowering method.
  struct ValueRotInfo {
    SDValue V;
    unsigned RLAmt = std::numeric_limits<unsigned>::max();
    unsigned NumGroups = 0;
    unsigned FirstGroupStartIdx = std::numeric_limits<unsigned>::max();
    bool Repl32 = false;
 
    ValueRotInfo() = default;
 
    // For sorting (in reverse order) by NumGroups, and then by
    // FirstGroupStartIdx.
    bool operator < (const ValueRotInfo &Other) const {
      // We need to sort so that the non-Repl32 come first because, when we're
      // doing masking, the Repl32 bit groups might be subsumed into the 64-bit
      // masking operation.
      if (Repl32 < Other.Repl32)
        return true;
      else if (Repl32 > Other.Repl32)
        return false;
      else if (NumGroups > Other.NumGroups)
        return true;
      else if (NumGroups < Other.NumGroups)
        return false;
      else if (RLAmt == 0 && Other.RLAmt != 0)
        return true;
      else if (RLAmt != 0 && Other.RLAmt == 0)
        return false;
      else if (FirstGroupStartIdx < Other.FirstGroupStartIdx)
        return true;
      return false;
    }
  };
 
  using ValueBitsMemoizedValue = std::pair<bool, SmallVector<ValueBit, 64>>;
  using ValueBitsMemoizer =
      DenseMap<SDValue, std::unique_ptr<ValueBitsMemoizedValue>>;
  ValueBitsMemoizer Memoizer;
 
  // Return a pair of bool and a SmallVector pointer to a memoization entry.
  // The bool is true if something interesting was deduced, otherwise if we're
  // providing only a generic representation of V (or something else likewise
  // uninteresting for instruction selection) through the SmallVector.
  std::pair<bool, SmallVector<ValueBit, 64> *> getValueBits(SDValue V,
                                                            unsigned NumBits) {
    auto &ValueEntry = Memoizer[V];
    if (ValueEntry)
      return std::make_pair(ValueEntry->first, &ValueEntry->second);
    ValueEntry.reset(new ValueBitsMemoizedValue());
    bool &Interesting = ValueEntry->first;
    SmallVector<ValueBit, 64> &Bits = ValueEntry->second;
    Bits.resize(NumBits);
 
    switch (V.getOpcode()) {
    default: break;
    case ISD::ROTL:
      if (isa<ConstantSDNode>(V.getOperand(1))) {
        unsigned RotAmt = V.getConstantOperandVal(1);
 
        const auto &LHSBits = *getValueBits(V.getOperand(0), NumBits).second;
 
        for (unsigned i = 0; i < NumBits; ++i)
          Bits[i] = LHSBits[i < RotAmt ? i + (NumBits - RotAmt) : i - RotAmt];
 
        return std::make_pair(Interesting = true, &Bits);
      }
      break;
    case ISD::SHL:
    case PPCISD::SHL:
      if (isa<ConstantSDNode>(V.getOperand(1))) {
        unsigned ShiftAmt = V.getConstantOperandVal(1);
 
        const auto &LHSBits = *getValueBits(V.getOperand(0), NumBits).second;
 
        for (unsigned i = ShiftAmt; i < NumBits; ++i)
          Bits[i] = LHSBits[i - ShiftAmt];
 
        for (unsigned i = 0; i < ShiftAmt; ++i)
          Bits[i] = ValueBit(ValueBit::ConstZero);
 
        return std::make_pair(Interesting = true, &Bits);
      }
      break;
    case ISD::SRL:
    case PPCISD::SRL:
      if (isa<ConstantSDNode>(V.getOperand(1))) {
        unsigned ShiftAmt = V.getConstantOperandVal(1);
 
        const auto &LHSBits = *getValueBits(V.getOperand(0), NumBits).second;
 
        for (unsigned i = 0; i < NumBits - ShiftAmt; ++i)
          Bits[i] = LHSBits[i + ShiftAmt];
 
        for (unsigned i = NumBits - ShiftAmt; i < NumBits; ++i)
          Bits[i] = ValueBit(ValueBit::ConstZero);
 
        return std::make_pair(Interesting = true, &Bits);
      }
      break;
    case ISD::AND:
      if (isa<ConstantSDNode>(V.getOperand(1))) {
        uint64_t Mask = V.getConstantOperandVal(1);
 
        const SmallVector<ValueBit, 64> *LHSBits;
        // Mark this as interesting, only if the LHS was also interesting. This
        // prevents the overall procedure from matching a single immediate 'and'
        // (which is non-optimal because such an and might be folded with other
        // things if we don't select it here).
        std::tie(Interesting, LHSBits) = getValueBits(V.getOperand(0), NumBits);
 
        for (unsigned i = 0; i < NumBits; ++i)
          if (((Mask >> i) & 1) == 1)
            Bits[i] = (*LHSBits)[i];
          else {
            // AND instruction masks this bit. If the input is already zero,
            // we have nothing to do here. Otherwise, make the bit ConstZero.
            if ((*LHSBits)[i].isZero())
              Bits[i] = (*LHSBits)[i];
            else
              Bits[i] = ValueBit(ValueBit::ConstZero);
          }
 
        return std::make_pair(Interesting, &Bits);
      }
      break;
    case ISD::OR: {
      const auto &LHSBits = *getValueBits(V.getOperand(0), NumBits).second;
      const auto &RHSBits = *getValueBits(V.getOperand(1), NumBits).second;
 
      bool AllDisjoint = true;
      SDValue LastVal = SDValue();
      unsigned LastIdx = 0;
      for (unsigned i = 0; i < NumBits; ++i) {
        if (LHSBits[i].isZero() && RHSBits[i].isZero()) {
          // If both inputs are known to be zero and one is ConstZero and
          // another is VariableKnownToBeZero, we can select whichever
          // we like. To minimize the number of bit groups, we select
          // VariableKnownToBeZero if this bit is the next bit of the same
          // input variable from the previous bit. Otherwise, we select
          // ConstZero.
          if (LHSBits[i].hasValue() && LHSBits[i].getValue() == LastVal &&
              LHSBits[i].getValueBitIndex() == LastIdx + 1)
            Bits[i] = LHSBits[i];
          else if (RHSBits[i].hasValue() && RHSBits[i].getValue() == LastVal &&
                   RHSBits[i].getValueBitIndex() == LastIdx + 1)
            Bits[i] = RHSBits[i];
          else
            Bits[i] = ValueBit(ValueBit::ConstZero);
        }
        else if (LHSBits[i].isZero())
          Bits[i] = RHSBits[i];
        else if (RHSBits[i].isZero())
          Bits[i] = LHSBits[i];
        else {
          AllDisjoint = false;
          break;
        }
        // We remember the value and bit index of this bit.
        if (Bits[i].hasValue()) {
          LastVal = Bits[i].getValue();
          LastIdx = Bits[i].getValueBitIndex();
        }
        else {
          if (LastVal) LastVal = SDValue();
          LastIdx = 0;
        }
      }
 
      if (!AllDisjoint)
        break;
 
      return std::make_pair(Interesting = true, &Bits);
    }
    case ISD::ZERO_EXTEND: {
      // We support only the case with zero extension from i32 to i64 so far.
      if (V.getValueType() != MVT::i64 ||
          V.getOperand(0).getValueType() != MVT::i32)
        break;
 
      const SmallVector<ValueBit, 64> *LHSBits;
      const unsigned NumOperandBits = 32;
      std::tie(Interesting, LHSBits) = getValueBits(V.getOperand(0),
                                                    NumOperandBits);
 
      for (unsigned i = 0; i < NumOperandBits; ++i)
        Bits[i] = (*LHSBits)[i];
 
      for (unsigned i = NumOperandBits; i < NumBits; ++i)
        Bits[i] = ValueBit(ValueBit::ConstZero);
 
      return std::make_pair(Interesting, &Bits);
    }
    case ISD::TRUNCATE: {
      EVT FromType = V.getOperand(0).getValueType();
      EVT ToType = V.getValueType();
      // We support only the case with truncate from i64 to i32.
      if (FromType != MVT::i64 || ToType != MVT::i32)
        break;
      const unsigned NumAllBits = FromType.getSizeInBits();
      SmallVector<ValueBit, 64> *InBits;
      std::tie(Interesting, InBits) = getValueBits(V.getOperand(0),
                                                    NumAllBits);
      const unsigned NumValidBits = ToType.getSizeInBits();
 
      // A 32-bit instruction cannot touch upper 32-bit part of 64-bit value.
      // So, we cannot include this truncate.
      bool UseUpper32bit = false;
      for (unsigned i = 0; i < NumValidBits; ++i)
        if ((*InBits)[i].hasValue() && (*InBits)[i].getValueBitIndex() >= 32) {
          UseUpper32bit = true;
          break;
        }
      if (UseUpper32bit)
        break;
 
      for (unsigned i = 0; i < NumValidBits; ++i)
        Bits[i] = (*InBits)[i];
 
      return std::make_pair(Interesting, &Bits);
    }
    case ISD::AssertZext: {
      // For AssertZext, we look through the operand and
      // mark the bits known to be zero.
      const SmallVector<ValueBit, 64> *LHSBits;
      std::tie(Interesting, LHSBits) = getValueBits(V.getOperand(0),
                                                    NumBits);
 
      EVT FromType = cast<VTSDNode>(V.getOperand(1))->getVT();
      const unsigned NumValidBits = FromType.getSizeInBits();
      for (unsigned i = 0; i < NumValidBits; ++i)
        Bits[i] = (*LHSBits)[i];
 
      // These bits are known to be zero but the AssertZext may be from a value
      // that already has some constant zero bits (i.e. from a masking and).
      for (unsigned i = NumValidBits; i < NumBits; ++i)
        Bits[i] = (*LHSBits)[i].hasValue()
                      ? ValueBit((*LHSBits)[i].getValue(),
                                 (*LHSBits)[i].getValueBitIndex(),
                                 ValueBit::VariableKnownToBeZero)
                      : ValueBit(ValueBit::ConstZero);
 
      return std::make_pair(Interesting, &Bits);
    }
    case ISD::LOAD:
      LoadSDNode *LD = cast<LoadSDNode>(V);
      if (ISD::isZEXTLoad(V.getNode()) && V.getResNo() == 0) {
        EVT VT = LD->getMemoryVT();
        const unsigned NumValidBits = VT.getSizeInBits();
 
        for (unsigned i = 0; i < NumValidBits; ++i)
          Bits[i] = ValueBit(V, i);
 
        // These bits are known to be zero.
        for (unsigned i = NumValidBits; i < NumBits; ++i)
          Bits[i] = ValueBit(V, i, ValueBit::VariableKnownToBeZero);
 
        // Zero-extending load itself cannot be optimized. So, it is not
        // interesting by itself though it gives useful information.
        return std::make_pair(Interesting = false, &Bits);
      }
      break;
    }
 
    for (unsigned i = 0; i < NumBits; ++i)
      Bits[i] = ValueBit(V, i);
 
    return std::make_pair(Interesting = false, &Bits);
  }
 
  // For each value (except the constant ones), compute the left-rotate amount
  // to get it from its original to final position.
  void computeRotationAmounts() {
    NeedMask = false;
    RLAmt.resize(Bits.size());
    for (unsigned i = 0; i < Bits.size(); ++i)
      if (Bits[i].hasValue()) {
        unsigned VBI = Bits[i].getValueBitIndex();
        if (i >= VBI)
          RLAmt[i] = i - VBI;
        else
          RLAmt[i] = Bits.size() - (VBI - i);
      } else if (Bits[i].isZero()) {
        NeedMask = true;
        RLAmt[i] = UINT32_MAX;
      } else {
        llvm_unreachable("Unknown value bit type");
      }
  }
 
  // Collect groups of consecutive bits with the same underlying value and
  // rotation factor. If we're doing late masking, we ignore zeros, otherwise
  // they break up groups.
  void collectBitGroups(bool LateMask) {
    BitGroups.clear();
 
    unsigned LastRLAmt = RLAmt[0];
    SDValue LastValue = Bits[0].hasValue() ? Bits[0].getValue() : SDValue();
    unsigned LastGroupStartIdx = 0;
    bool IsGroupOfZeros = !Bits[LastGroupStartIdx].hasValue();
    for (unsigned i = 1; i < Bits.size(); ++i) {
      unsigned ThisRLAmt = RLAmt[i];
      SDValue ThisValue = Bits[i].hasValue() ? Bits[i].getValue() : SDValue();
      if (LateMask && !ThisValue) {
        ThisValue = LastValue;
        ThisRLAmt = LastRLAmt;
        // If we're doing late masking, then the first bit group always starts
        // at zero (even if the first bits were zero).
        if (BitGroups.empty())
          LastGroupStartIdx = 0;
      }
 
      // If this bit is known to be zero and the current group is a bit group
      // of zeros, we do not need to terminate the current bit group even the
      // Value or RLAmt does not match here. Instead, we terminate this group
      // when the first non-zero bit appears later.
      if (IsGroupOfZeros && Bits[i].isZero())
        continue;
 
      // If this bit has the same underlying value and the same rotate factor as
      // the last one, then they're part of the same group.
      if (ThisRLAmt == LastRLAmt && ThisValue == LastValue)
        // We cannot continue the current group if this bits is not known to
        // be zero in a bit group of zeros.
        if (!(IsGroupOfZeros && ThisValue && !Bits[i].isZero()))
          continue;
 
      if (LastValue.getNode())
        BitGroups.push_back(BitGroup(LastValue, LastRLAmt, LastGroupStartIdx,
                                     i-1));
      LastRLAmt = ThisRLAmt;
      LastValue = ThisValue;
      LastGroupStartIdx = i;
      IsGroupOfZeros = !Bits[LastGroupStartIdx].hasValue();
    }
    if (LastValue.getNode())
      BitGroups.push_back(BitGroup(LastValue, LastRLAmt, LastGroupStartIdx,
                                   Bits.size()-1));
 
    if (BitGroups.empty())
      return;
 
    // We might be able to combine the first and last groups.
    if (BitGroups.size() > 1) {
      // If the first and last groups are the same, then remove the first group
      // in favor of the last group, making the ending index of the last group
      // equal to the ending index of the to-be-removed first group.
      if (BitGroups[0].StartIdx == 0 &&
          BitGroups[BitGroups.size()-1].EndIdx == Bits.size()-1 &&
          BitGroups[0].V == BitGroups[BitGroups.size()-1].V &&
          BitGroups[0].RLAmt == BitGroups[BitGroups.size()-1].RLAmt) {
        LLVM_DEBUG(dbgs() << "\tcombining final bit group with initial one\n");
        BitGroups[BitGroups.size()-1].EndIdx = BitGroups[0].EndIdx;
        BitGroups.erase(BitGroups.begin());
      }
    }
  }
 
  // Take all (SDValue, RLAmt) pairs and sort them by the number of groups
  // associated with each. If the number of groups are same, we prefer a group
  // which does not require rotate, i.e. RLAmt is 0, to avoid the first rotate
  // instruction. If there is a degeneracy, pick the one that occurs
  // first (in the final value).
  void collectValueRotInfo() {
    ValueRots.clear();
 
    for (auto &BG : BitGroups) {
      unsigned RLAmtKey = BG.RLAmt + (BG.Repl32 ? 64 : 0);
      ValueRotInfo &VRI = ValueRots[std::make_pair(BG.V, RLAmtKey)];
      VRI.V = BG.V;
      VRI.RLAmt = BG.RLAmt;
      VRI.Repl32 = BG.Repl32;
      VRI.NumGroups += 1;
      VRI.FirstGroupStartIdx = std::min(VRI.FirstGroupStartIdx, BG.StartIdx);
    }
 
    // Now that we've collected the various ValueRotInfo instances, we need to
    // sort them.
    ValueRotsVec.clear();
    for (auto &I : ValueRots) {
      ValueRotsVec.push_back(I.second);
    }
    llvm::sort(ValueRotsVec);
  }
 
  // In 64-bit mode, rlwinm and friends have a rotation operator that
  // replicates the low-order 32 bits into the high-order 32-bits. The mask
  // indices of these instructions can only be in the lower 32 bits, so they
  // can only represent some 64-bit bit groups. However, when they can be used,
  // the 32-bit replication can be used to represent, as a single bit group,
  // otherwise separate bit groups. We'll convert to replicated-32-bit bit
  // groups when possible. Returns true if any of the bit groups were
  // converted.
  void assignRepl32BitGroups() {
    // If we have bits like this:
    //
    // Indices:    15 14 13 12 11 10 9 8  7  6  5  4  3  2  1  0
    // V bits: ... 7  6  5  4  3  2  1 0 31 30 29 28 27 26 25 24
    // Groups:    |      RLAmt = 8      |      RLAmt = 40       |
    //
    // But, making use of a 32-bit operation that replicates the low-order 32
    // bits into the high-order 32 bits, this can be one bit group with a RLAmt
    // of 8.
 
    auto IsAllLow32 = [this](BitGroup & BG) {
      if (BG.StartIdx <= BG.EndIdx) {
        for (unsigned i = BG.StartIdx; i <= BG.EndIdx; ++i) {
          if (!Bits[i].hasValue())
            continue;
          if (Bits[i].getValueBitIndex() >= 32)
            return false;
        }
      } else {
        for (unsigned i = BG.StartIdx; i < Bits.size(); ++i) {
          if (!Bits[i].hasValue())
            continue;
          if (Bits[i].getValueBitIndex() >= 32)
            return false;
        }
        for (unsigned i = 0; i <= BG.EndIdx; ++i) {
          if (!Bits[i].hasValue())
            continue;
          if (Bits[i].getValueBitIndex() >= 32)
            return false;
        }
      }
 
      return true;
    };
 
    for (auto &BG : BitGroups) {
      // If this bit group has RLAmt of 0 and will not be merged with
      // another bit group, we don't benefit from Repl32. We don't mark
      // such group to give more freedom for later instruction selection.
      if (BG.RLAmt == 0) {
        auto PotentiallyMerged = [this](BitGroup & BG) {
          for (auto &BG2 : BitGroups)
            if (&BG != &BG2 && BG.V == BG2.V &&
                (BG2.RLAmt == 0 || BG2.RLAmt == 32))
              return true;
          return false;
        };
        if (!PotentiallyMerged(BG))
          continue;
      }
      if (BG.StartIdx < 32 && BG.EndIdx < 32) {
        if (IsAllLow32(BG)) {
          if (BG.RLAmt >= 32) {
            BG.RLAmt -= 32;
            BG.Repl32CR = true;
          }
 
          BG.Repl32 = true;
 
          LLVM_DEBUG(dbgs() << "\t32-bit replicated bit group for "
                            << BG.V.getNode() << " RLAmt = " << BG.RLAmt << " ["
                            << BG.StartIdx << ", " << BG.EndIdx << "]\n");
        }
      }
    }
 
    // Now walk through the bit groups, consolidating where possible.
    for (auto I = BitGroups.begin(); I != BitGroups.end();) {
      // We might want to remove this bit group by merging it with the previous
      // group (which might be the ending group).
      auto IP = (I == BitGroups.begin()) ?
                std::prev(BitGroups.end()) : std::prev(I);
      if (I->Repl32 && IP->Repl32 && I->V == IP->V && I->RLAmt == IP->RLAmt &&
          I->StartIdx == (IP->EndIdx + 1) % 64 && I != IP) {
 
        LLVM_DEBUG(dbgs() << "\tcombining 32-bit replicated bit group for "
                          << I->V.getNode() << " RLAmt = " << I->RLAmt << " ["
                          << I->StartIdx << ", " << I->EndIdx
                          << "] with group with range [" << IP->StartIdx << ", "
                          << IP->EndIdx << "]\n");
 
        IP->EndIdx = I->EndIdx;
        IP->Repl32CR = IP->Repl32CR || I->Repl32CR;
        IP->Repl32Coalesced = true;
        I = BitGroups.erase(I);
        continue;
      } else {
        // There is a special case worth handling: If there is a single group
        // covering the entire upper 32 bits, and it can be merged with both
        // the next and previous groups (which might be the same group), then
        // do so. If it is the same group (so there will be only one group in
        // total), then we need to reverse the order of the range so that it
        // covers the entire 64 bits.
        if (I->StartIdx == 32 && I->EndIdx == 63) {
          assert(std::next(I) == BitGroups.end() &&
                 "bit group ends at index 63 but there is another?");
          auto IN = BitGroups.begin();
 
          if (IP->Repl32 && IN->Repl32 && I->V == IP->V && I->V == IN->V &&
              (I->RLAmt % 32) == IP->RLAmt && (I->RLAmt % 32) == IN->RLAmt &&
              IP->EndIdx == 31 && IN->StartIdx == 0 && I != IP &&
              IsAllLow32(*I)) {
 
            LLVM_DEBUG(dbgs() << "\tcombining bit group for " << I->V.getNode()
                              << " RLAmt = " << I->RLAmt << " [" << I->StartIdx
                              << ", " << I->EndIdx
                              << "] with 32-bit replicated groups with ranges ["
                              << IP->StartIdx << ", " << IP->EndIdx << "] and ["
                              << IN->StartIdx << ", " << IN->EndIdx << "]\n");
 
            if (IP == IN) {
              // There is only one other group; change it to cover the whole
              // range (backward, so that it can still be Repl32 but cover the
              // whole 64-bit range).
              IP->StartIdx = 31;
              IP->EndIdx = 30;
              IP->Repl32CR = IP->Repl32CR || I->RLAmt >= 32;
              IP->Repl32Coalesced = true;
              I = BitGroups.erase(I);
            } else {
              // There are two separate groups, one before this group and one
              // after us (at the beginning). We're going to remove this group,
              // but also the group at the very beginning.
              IP->EndIdx = IN->EndIdx;
              IP->Repl32CR = IP->Repl32CR || IN->Repl32CR || I->RLAmt >= 32;
              IP->Repl32Coalesced = true;
              I = BitGroups.erase(I);
              BitGroups.erase(BitGroups.begin());
            }
 
            // This must be the last group in the vector (and we might have
            // just invalidated the iterator above), so break here.
            break;
          }
        }
      }
 
      ++I;
    }
  }
 
  SDValue getI32Imm(unsigned Imm, const SDLoc &dl) {
    return CurDAG->getTargetConstant(Imm, dl, MVT::i32);
  }
 
  uint64_t getZerosMask() {
    uint64_t Mask = 0;
    for (unsigned i = 0; i < Bits.size(); ++i) {
      if (Bits[i].hasValue())
        continue;
      Mask |= (UINT64_C(1) << i);
    }
 
    return ~Mask;
  }
 
  // This method extends an input value to 64 bit if input is 32-bit integer.
  // While selecting instructions in BitPermutationSelector in 64-bit mode,
  // an input value can be a 32-bit integer if a ZERO_EXTEND node is included.
  // In such case, we extend it to 64 bit to be consistent with other values.
  SDValue ExtendToInt64(SDValue V, const SDLoc &dl) {
    if (V.getValueSizeInBits() == 64)
      return V;
 
    assert(V.getValueSizeInBits() == 32);
    SDValue SubRegIdx = CurDAG->getTargetConstant(PPC::sub_32, dl, MVT::i32);
    SDValue ImDef = SDValue(CurDAG->getMachineNode(PPC::IMPLICIT_DEF, dl,
                                                   MVT::i64), 0);
    SDValue ExtVal = SDValue(CurDAG->getMachineNode(PPC::INSERT_SUBREG, dl,
                                                    MVT::i64, ImDef, V,
                                                    SubRegIdx), 0);
    return ExtVal;
  }
 
  SDValue TruncateToInt32(SDValue V, const SDLoc &dl) {
    if (V.getValueSizeInBits() == 32)
      return V;
 
    assert(V.getValueSizeInBits() == 64);
    SDValue SubRegIdx = CurDAG->getTargetConstant(PPC::sub_32, dl, MVT::i32);
    SDValue SubVal = SDValue(CurDAG->getMachineNode(PPC::EXTRACT_SUBREG, dl,
                                                    MVT::i32, V, SubRegIdx), 0);
    return SubVal;
  }
 
  // Depending on the number of groups for a particular value, it might be
  // better to rotate, mask explicitly (using andi/andis), and then or the
  // result. Select this part of the result first.
  void SelectAndParts32(const SDLoc &dl, SDValue &Res, unsigned *InstCnt) {
    if (BPermRewriterNoMasking)
      return;
 
    for (ValueRotInfo &VRI : ValueRotsVec) {
      unsigned Mask = 0;
      for (unsigned i = 0; i < Bits.size(); ++i) {
        if (!Bits[i].hasValue() || Bits[i].getValue() != VRI.V)
          continue;
        if (RLAmt[i] != VRI.RLAmt)
          continue;
        Mask |= (1u << i);
      }
 
      // Compute the masks for andi/andis that would be necessary.
      unsigned ANDIMask = (Mask & UINT16_MAX), ANDISMask = Mask >> 16;
      assert((ANDIMask != 0 || ANDISMask != 0) &&
             "No set bits in mask for value bit groups");
      bool NeedsRotate = VRI.RLAmt != 0;
 
      // We're trying to minimize the number of instructions. If we have one
      // group, using one of andi/andis can break even.  If we have three
      // groups, we can use both andi and andis and break even (to use both
      // andi and andis we also need to or the results together). We need four
      // groups if we also need to rotate. To use andi/andis we need to do more
      // than break even because rotate-and-mask instructions tend to be easier
      // to schedule.
 
      // FIXME: We've biased here against using andi/andis, which is right for
      // POWER cores, but not optimal everywhere. For example, on the A2,
      // andi/andis have single-cycle latency whereas the rotate-and-mask
      // instructions take two cycles, and it would be better to bias toward
      // andi/andis in break-even cases.
 
      unsigned NumAndInsts = (unsigned) NeedsRotate +
                             (unsigned) (ANDIMask != 0) +
                             (unsigned) (ANDISMask != 0) +
                             (unsigned) (ANDIMask != 0 && ANDISMask != 0) +
                             (unsigned) (bool) Res;
 
      LLVM_DEBUG(dbgs() << "\t\trotation groups for " << VRI.V.getNode()
                        << " RL: " << VRI.RLAmt << ":"
                        << "\n\t\t\tisel using masking: " << NumAndInsts
                        << " using rotates: " << VRI.NumGroups << "\n");
 
      if (NumAndInsts >= VRI.NumGroups)
        continue;
 
      LLVM_DEBUG(dbgs() << "\t\t\t\tusing masking\n");
 
      if (InstCnt) *InstCnt += NumAndInsts;
 
      SDValue VRot;
      if (VRI.RLAmt) {
        SDValue Ops[] =
          { TruncateToInt32(VRI.V, dl), getI32Imm(VRI.RLAmt, dl),
            getI32Imm(0, dl), getI32Imm(31, dl) };
        VRot = SDValue(CurDAG->getMachineNode(PPC::RLWINM, dl, MVT::i32,
                                              Ops), 0);
      } else {
        VRot = TruncateToInt32(VRI.V, dl);
      }
 
      SDValue ANDIVal, ANDISVal;
      if (ANDIMask != 0)
        ANDIVal = SDValue(CurDAG->getMachineNode(PPC::ANDI_rec, dl, MVT::i32,
                                                 VRot, getI32Imm(ANDIMask, dl)),
                          0);
      if (ANDISMask != 0)
        ANDISVal =
            SDValue(CurDAG->getMachineNode(PPC::ANDIS_rec, dl, MVT::i32, VRot,
                                           getI32Imm(ANDISMask, dl)),
                    0);
 
      SDValue TotalVal;
      if (!ANDIVal)
        TotalVal = ANDISVal;
      else if (!ANDISVal)
        TotalVal = ANDIVal;
      else
        TotalVal = SDValue(CurDAG->getMachineNode(PPC::OR, dl, MVT::i32,
                             ANDIVal, ANDISVal), 0);
 
      if (!Res)
        Res = TotalVal;
      else
        Res = SDValue(CurDAG->getMachineNode(PPC::OR, dl, MVT::i32,
                        Res, TotalVal), 0);
 
      // Now, remove all groups with this underlying value and rotation
      // factor.
      eraseMatchingBitGroups([VRI](const BitGroup &BG) {
        return BG.V == VRI.V && BG.RLAmt == VRI.RLAmt;
      });
    }
  }
 
  // Instruction selection for the 32-bit case.
  SDNode *Select32(SDNode *N, bool LateMask, unsigned *InstCnt) {
    SDLoc dl(N);
    SDValue Res;
 
    if (InstCnt) *InstCnt = 0;
 
    // Take care of cases that should use andi/andis first.
    SelectAndParts32(dl, Res, InstCnt);
 
    // If we've not yet selected a 'starting' instruction, and we have no zeros
    // to fill in, select the (Value, RLAmt) with the highest priority (largest
    // number of groups), and start with this rotated value.
    if ((!NeedMask || LateMask) && !Res) {
      ValueRotInfo &VRI = ValueRotsVec[0];
      if (VRI.RLAmt) {
        if (InstCnt) *InstCnt += 1;
        SDValue Ops[] =
          { TruncateToInt32(VRI.V, dl), getI32Imm(VRI.RLAmt, dl),
            getI32Imm(0, dl), getI32Imm(31, dl) };
        Res = SDValue(CurDAG->getMachineNode(PPC::RLWINM, dl, MVT::i32, Ops),
                      0);
      } else {
        Res = TruncateToInt32(VRI.V, dl);
      }
 
      // Now, remove all groups with this underlying value and rotation factor.
      eraseMatchingBitGroups([VRI](const BitGroup &BG) {
        return BG.V == VRI.V && BG.RLAmt == VRI.RLAmt;
      });
    }
 
    if (InstCnt) *InstCnt += BitGroups.size();
 
    // Insert the other groups (one at a time).
    for (auto &BG : BitGroups) {
      if (!Res) {
        SDValue Ops[] =
          { TruncateToInt32(BG.V, dl), getI32Imm(BG.RLAmt, dl),
            getI32Imm(Bits.size() - BG.EndIdx - 1, dl),
            getI32Imm(Bits.size() - BG.StartIdx - 1, dl) };
        Res = SDValue(CurDAG->getMachineNode(PPC::RLWINM, dl, MVT::i32, Ops), 0);
      } else {
        SDValue Ops[] =
          { Res, TruncateToInt32(BG.V, dl), getI32Imm(BG.RLAmt, dl),
              getI32Imm(Bits.size() - BG.EndIdx - 1, dl),
            getI32Imm(Bits.size() - BG.StartIdx - 1, dl) };
        Res = SDValue(CurDAG->getMachineNode(PPC::RLWIMI, dl, MVT::i32, Ops), 0);
      }
    }
 
    if (LateMask) {
      unsigned Mask = (unsigned) getZerosMask();
 
      unsigned ANDIMask = (Mask & UINT16_MAX), ANDISMask = Mask >> 16;
      assert((ANDIMask != 0 || ANDISMask != 0) &&
             "No set bits in zeros mask?");
 
      if (InstCnt) *InstCnt += (unsigned) (ANDIMask != 0) +
                               (unsigned) (ANDISMask != 0) +
                               (unsigned) (ANDIMask != 0 && ANDISMask != 0);
 
      SDValue ANDIVal, ANDISVal;
      if (ANDIMask != 0)
        ANDIVal = SDValue(CurDAG->getMachineNode(PPC::ANDI_rec, dl, MVT::i32,
                                                 Res, getI32Imm(ANDIMask, dl)),
                          0);
      if (ANDISMask != 0)
        ANDISVal =
            SDValue(CurDAG->getMachineNode(PPC::ANDIS_rec, dl, MVT::i32, Res,
                                           getI32Imm(ANDISMask, dl)),
                    0);
 
      if (!ANDIVal)
        Res = ANDISVal;
      else if (!ANDISVal)
        Res = ANDIVal;
      else
        Res = SDValue(CurDAG->getMachineNode(PPC::OR, dl, MVT::i32,
                        ANDIVal, ANDISVal), 0);
    }
 
    return Res.getNode();
  }
 
  unsigned SelectRotMask64Count(unsigned RLAmt, bool Repl32,
                                unsigned MaskStart, unsigned MaskEnd,
                                bool IsIns) {
    // In the notation used by the instructions, 'start' and 'end' are reversed
    // because bits are counted from high to low order.
    unsigned InstMaskStart = 64 - MaskEnd - 1,
             InstMaskEnd   = 64 - MaskStart - 1;
 
    if (Repl32)
      return 1;
 
    if ((!IsIns && (InstMaskEnd == 63 || InstMaskStart == 0)) ||
        InstMaskEnd == 63 - RLAmt)
      return 1;
 
    return 2;
  }
 
  // For 64-bit values, not all combinations of rotates and masks are
  // available. Produce one if it is available.
  SDValue SelectRotMask64(SDValue V, const SDLoc &dl, unsigned RLAmt,
                          bool Repl32, unsigned MaskStart, unsigned MaskEnd,
                          unsigned *InstCnt = nullptr) {
    // In the notation used by the instructions, 'start' and 'end' are reversed
    // because bits are counted from high to low order.
    unsigned InstMaskStart = 64 - MaskEnd - 1,
             InstMaskEnd   = 64 - MaskStart - 1;
 
    if (InstCnt) *InstCnt += 1;
 
    if (Repl32) {
      // This rotation amount assumes that the lower 32 bits of the quantity
      // are replicated in the high 32 bits by the rotation operator (which is
      // done by rlwinm and friends).
      assert(InstMaskStart >= 32 && "Mask cannot start out of range");
      assert(InstMaskEnd   >= 32 && "Mask cannot end out of range");
      SDValue Ops[] =
        { ExtendToInt64(V, dl), getI32Imm(RLAmt, dl),
          getI32Imm(InstMaskStart - 32, dl), getI32Imm(InstMaskEnd - 32, dl) };
      return SDValue(CurDAG->getMachineNode(PPC::RLWINM8, dl, MVT::i64,
                                            Ops), 0);
    }
 
    if (InstMaskEnd == 63) {
      SDValue Ops[] =
        { ExtendToInt64(V, dl), getI32Imm(RLAmt, dl),
          getI32Imm(InstMaskStart, dl) };
      return SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, Ops), 0);
    }
 
    if (InstMaskStart == 0) {
      SDValue Ops[] =
        { ExtendToInt64(V, dl), getI32Imm(RLAmt, dl),
          getI32Imm(InstMaskEnd, dl) };
      return SDValue(CurDAG->getMachineNode(PPC::RLDICR, dl, MVT::i64, Ops), 0);
    }
 
    if (InstMaskEnd == 63 - RLAmt) {
      SDValue Ops[] =
        { ExtendToInt64(V, dl), getI32Imm(RLAmt, dl),
          getI32Imm(InstMaskStart, dl) };
      return SDValue(CurDAG->getMachineNode(PPC::RLDIC, dl, MVT::i64, Ops), 0);
    }
 
    // We cannot do this with a single instruction, so we'll use two. The
    // problem is that we're not free to choose both a rotation amount and mask
    // start and end independently. We can choose an arbitrary mask start and
    // end, but then the rotation amount is fixed. Rotation, however, can be
    // inverted, and so by applying an "inverse" rotation first, we can get the
    // desired result.
    if (InstCnt) *InstCnt += 1;
 
    // The rotation mask for the second instruction must be MaskStart.
    unsigned RLAmt2 = MaskStart;
    // The first instruction must rotate V so that the overall rotation amount
    // is RLAmt.
    unsigned RLAmt1 = (64 + RLAmt - RLAmt2) % 64;
    if (RLAmt1)
      V = SelectRotMask64(V, dl, RLAmt1, false, 0, 63);
    return SelectRotMask64(V, dl, RLAmt2, false, MaskStart, MaskEnd);
  }
 
  // For 64-bit values, not all combinations of rotates and masks are
  // available. Produce a rotate-mask-and-insert if one is available.
  SDValue SelectRotMaskIns64(SDValue Base, SDValue V, const SDLoc &dl,
                             unsigned RLAmt, bool Repl32, unsigned MaskStart,
                             unsigned MaskEnd, unsigned *InstCnt = nullptr) {
    // In the notation used by the instructions, 'start' and 'end' are reversed
    // because bits are counted from high to low order.
    unsigned InstMaskStart = 64 - MaskEnd - 1,
             InstMaskEnd   = 64 - MaskStart - 1;
 
    if (InstCnt) *InstCnt += 1;
 
    if (Repl32) {
      // This rotation amount assumes that the lower 32 bits of the quantity
      // are replicated in the high 32 bits by the rotation operator (which is
      // done by rlwinm and friends).
      assert(InstMaskStart >= 32 && "Mask cannot start out of range");
      assert(InstMaskEnd   >= 32 && "Mask cannot end out of range");
      SDValue Ops[] =
        { ExtendToInt64(Base, dl), ExtendToInt64(V, dl), getI32Imm(RLAmt, dl),
          getI32Imm(InstMaskStart - 32, dl), getI32Imm(InstMaskEnd - 32, dl) };
      return SDValue(CurDAG->getMachineNode(PPC::RLWIMI8, dl, MVT::i64,
                                            Ops), 0);
    }
 
    if (InstMaskEnd == 63 - RLAmt) {
      SDValue Ops[] =
        { ExtendToInt64(Base, dl), ExtendToInt64(V, dl), getI32Imm(RLAmt, dl),
          getI32Imm(InstMaskStart, dl) };
      return SDValue(CurDAG->getMachineNode(PPC::RLDIMI, dl, MVT::i64, Ops), 0);
    }
 
    // We cannot do this with a single instruction, so we'll use two. The
    // problem is that we're not free to choose both a rotation amount and mask
    // start and end independently. We can choose an arbitrary mask start and
    // end, but then the rotation amount is fixed. Rotation, however, can be
    // inverted, and so by applying an "inverse" rotation first, we can get the
    // desired result.
    if (InstCnt) *InstCnt += 1;
 
    // The rotation mask for the second instruction must be MaskStart.
    unsigned RLAmt2 = MaskStart;
    // The first instruction must rotate V so that the overall rotation amount
    // is RLAmt.
    unsigned RLAmt1 = (64 + RLAmt - RLAmt2) % 64;
    if (RLAmt1)
      V = SelectRotMask64(V, dl, RLAmt1, false, 0, 63);
    return SelectRotMaskIns64(Base, V, dl, RLAmt2, false, MaskStart, MaskEnd);
  }
 
  void SelectAndParts64(const SDLoc &dl, SDValue &Res, unsigned *InstCnt) {
    if (BPermRewriterNoMasking)
      return;
 
    // The idea here is the same as in the 32-bit version, but with additional
    // complications from the fact that Repl32 might be true. Because we
    // aggressively convert bit groups to Repl32 form (which, for small
    // rotation factors, involves no other change), and then coalesce, it might
    // be the case that a single 64-bit masking operation could handle both
    // some Repl32 groups and some non-Repl32 groups. If converting to Repl32
    // form allowed coalescing, then we must use a 32-bit rotaton in order to
    // completely capture the new combined bit group.
 
    for (ValueRotInfo &VRI : ValueRotsVec) {
      uint64_t Mask = 0;
 
      // We need to add to the mask all bits from the associated bit groups.
      // If Repl32 is false, we need to add bits from bit groups that have
      // Repl32 true, but are trivially convertable to Repl32 false. Such a
      // group is trivially convertable if it overlaps only with the lower 32
      // bits, and the group has not been coalesced.
      auto MatchingBG = [VRI](const BitGroup &BG) {
        if (VRI.V != BG.V)
          return false;
 
        unsigned EffRLAmt = BG.RLAmt;
        if (!VRI.Repl32 && BG.Repl32) {
          if (BG.StartIdx < 32 && BG.EndIdx < 32 && BG.StartIdx <= BG.EndIdx &&
              !BG.Repl32Coalesced) {
            if (BG.Repl32CR)
              EffRLAmt += 32;
          } else {
            return false;
          }
        } else if (VRI.Repl32 != BG.Repl32) {
          return false;
        }
 
        return VRI.RLAmt == EffRLAmt;
      };
 
      for (auto &BG : BitGroups) {
        if (!MatchingBG(BG))
          continue;
 
        if (BG.StartIdx <= BG.EndIdx) {
          for (unsigned i = BG.StartIdx; i <= BG.EndIdx; ++i)
            Mask |= (UINT64_C(1) << i);
        } else {
          for (unsigned i = BG.StartIdx; i < Bits.size(); ++i)
            Mask |= (UINT64_C(1) << i);
          for (unsigned i = 0; i <= BG.EndIdx; ++i)
            Mask |= (UINT64_C(1) << i);
        }
      }
 
      // We can use the 32-bit andi/andis technique if the mask does not
      // require any higher-order bits. This can save an instruction compared
      // to always using the general 64-bit technique.
      bool Use32BitInsts = isUInt<32>(Mask);
      // Compute the masks for andi/andis that would be necessary.
      unsigned ANDIMask = (Mask & UINT16_MAX),
               ANDISMask = (Mask >> 16) & UINT16_MAX;
 
      bool NeedsRotate = VRI.RLAmt || (VRI.Repl32 && !isUInt<32>(Mask));
 
      unsigned NumAndInsts = (unsigned) NeedsRotate +
                             (unsigned) (bool) Res;
      unsigned NumOfSelectInsts = 0;
      selectI64Imm(CurDAG, dl, Mask, &NumOfSelectInsts);
      assert(NumOfSelectInsts > 0 && "Failed to select an i64 constant.");
      if (Use32BitInsts)
        NumAndInsts += (unsigned) (ANDIMask != 0) + (unsigned) (ANDISMask != 0) +
                       (unsigned) (ANDIMask != 0 && ANDISMask != 0);
      else
        NumAndInsts += NumOfSelectInsts + /* and */ 1;
 
      unsigned NumRLInsts = 0;
      bool FirstBG = true;
      bool MoreBG = false;
      for (auto &BG : BitGroups) {
        if (!MatchingBG(BG)) {
          MoreBG = true;
          continue;
        }
        NumRLInsts +=
          SelectRotMask64Count(BG.RLAmt, BG.Repl32, BG.StartIdx, BG.EndIdx,
                               !FirstBG);
        FirstBG = false;
      }
 
      LLVM_DEBUG(dbgs() << "\t\trotation groups for " << VRI.V.getNode()
                        << " RL: " << VRI.RLAmt << (VRI.Repl32 ? " (32):" : ":")
                        << "\n\t\t\tisel using masking: " << NumAndInsts
                        << " using rotates: " << NumRLInsts << "\n");
 
      // When we'd use andi/andis, we bias toward using the rotates (andi only
      // has a record form, and is cracked on POWER cores). However, when using
      // general 64-bit constant formation, bias toward the constant form,
      // because that exposes more opportunities for CSE.
      if (NumAndInsts > NumRLInsts)
        continue;
      // When merging multiple bit groups, instruction or is used.
      // But when rotate is used, rldimi can inert the rotated value into any
      // register, so instruction or can be avoided.
      if ((Use32BitInsts || MoreBG) && NumAndInsts == NumRLInsts)
        continue;
 
      LLVM_DEBUG(dbgs() << "\t\t\t\tusing masking\n");
 
      if (InstCnt) *InstCnt += NumAndInsts;
 
      SDValue VRot;
      // We actually need to generate a rotation if we have a non-zero rotation
      // factor or, in the Repl32 case, if we care about any of the
      // higher-order replicated bits. In the latter case, we generate a mask
      // backward so that it actually includes the entire 64 bits.
      if (VRI.RLAmt || (VRI.Repl32 && !isUInt<32>(Mask)))
        VRot = SelectRotMask64(VRI.V, dl, VRI.RLAmt, VRI.Repl32,
                               VRI.Repl32 ? 31 : 0, VRI.Repl32 ? 30 : 63);
      else
        VRot = VRI.V;
 
      SDValue TotalVal;
      if (Use32BitInsts) {
        assert((ANDIMask != 0 || ANDISMask != 0) &&
               "No set bits in mask when using 32-bit ands for 64-bit value");
 
        SDValue ANDIVal, ANDISVal;
        if (ANDIMask != 0)
          ANDIVal = SDValue(CurDAG->getMachineNode(PPC::ANDI8_rec, dl, MVT::i64,
                                                   ExtendToInt64(VRot, dl),
                                                   getI32Imm(ANDIMask, dl)),
                            0);
        if (ANDISMask != 0)
          ANDISVal =
              SDValue(CurDAG->getMachineNode(PPC::ANDIS8_rec, dl, MVT::i64,
                                             ExtendToInt64(VRot, dl),
                                             getI32Imm(ANDISMask, dl)),
                      0);
 
        if (!ANDIVal)
          TotalVal = ANDISVal;
        else if (!ANDISVal)
          TotalVal = ANDIVal;
        else
          TotalVal = SDValue(CurDAG->getMachineNode(PPC::OR8, dl, MVT::i64,
                               ExtendToInt64(ANDIVal, dl), ANDISVal), 0);
      } else {
        TotalVal = SDValue(selectI64Imm(CurDAG, dl, Mask), 0);
        TotalVal =
          SDValue(CurDAG->getMachineNode(PPC::AND8, dl, MVT::i64,
                                         ExtendToInt64(VRot, dl), TotalVal),
                  0);
     }
 
      if (!Res)
        Res = TotalVal;
      else
        Res = SDValue(CurDAG->getMachineNode(PPC::OR8, dl, MVT::i64,
                                             ExtendToInt64(Res, dl), TotalVal),
                      0);
 
      // Now, remove all groups with this underlying value and rotation
      // factor.
      eraseMatchingBitGroups(MatchingBG);
    }
  }
 
  // Instruction selection for the 64-bit case.
  SDNode *Select64(SDNode *N, bool LateMask, unsigned *InstCnt) {
    SDLoc dl(N);
    SDValue Res;
 
    if (InstCnt) *InstCnt = 0;
 
    // Take care of cases that should use andi/andis first.
    SelectAndParts64(dl, Res, InstCnt);
 
    // If we've not yet selected a 'starting' instruction, and we have no zeros
    // to fill in, select the (Value, RLAmt) with the highest priority (largest
    // number of groups), and start with this rotated value.
    if ((!NeedMask || LateMask) && !Res) {
      // If we have both Repl32 groups and non-Repl32 groups, the non-Repl32
      // groups will come first, and so the VRI representing the largest number
      // of groups might not be first (it might be the first Repl32 groups).
      unsigned MaxGroupsIdx = 0;
      if (!ValueRotsVec[0].Repl32) {
        for (unsigned i = 0, ie = ValueRotsVec.size(); i < ie; ++i)
          if (ValueRotsVec[i].Repl32) {
            if (ValueRotsVec[i].NumGroups > ValueRotsVec[0].NumGroups)
              MaxGroupsIdx = i;
            break;
          }
      }
 
      ValueRotInfo &VRI = ValueRotsVec[MaxGroupsIdx];
      bool NeedsRotate = false;
      if (VRI.RLAmt) {
        NeedsRotate = true;
      } else if (VRI.Repl32) {
        for (auto &BG : BitGroups) {
          if (BG.V != VRI.V || BG.RLAmt != VRI.RLAmt ||
              BG.Repl32 != VRI.Repl32)
            continue;
 
          // We don't need a rotate if the bit group is confined to the lower
          // 32 bits.
          if (BG.StartIdx < 32 && BG.EndIdx < 32 && BG.StartIdx < BG.EndIdx)
            continue;
 
          NeedsRotate = true;
          break;
        }
      }
 
      if (NeedsRotate)
        Res = SelectRotMask64(VRI.V, dl, VRI.RLAmt, VRI.Repl32,
                              VRI.Repl32 ? 31 : 0, VRI.Repl32 ? 30 : 63,
                              InstCnt);
      else
        Res = VRI.V;
 
      // Now, remove all groups with this underlying value and rotation factor.
      if (Res)
        eraseMatchingBitGroups([VRI](const BitGroup &BG) {
          return BG.V == VRI.V && BG.RLAmt == VRI.RLAmt &&
                 BG.Repl32 == VRI.Repl32;
        });
    }
 
    // Because 64-bit rotates are more flexible than inserts, we might have a
    // preference regarding which one we do first (to save one instruction).
    if (!Res)
      for (auto I = BitGroups.begin(), IE = BitGroups.end(); I != IE; ++I) {
        if (SelectRotMask64Count(I->RLAmt, I->Repl32, I->StartIdx, I->EndIdx,
                                false) <
            SelectRotMask64Count(I->RLAmt, I->Repl32, I->StartIdx, I->EndIdx,
                                true)) {
          if (I != BitGroups.begin()) {
            BitGroup BG = *I;
            BitGroups.erase(I);
            BitGroups.insert(BitGroups.begin(), BG);
          }
 
          break;
        }
      }
 
    // Insert the other groups (one at a time).
    for (auto &BG : BitGroups) {
      if (!Res)
        Res = SelectRotMask64(BG.V, dl, BG.RLAmt, BG.Repl32, BG.StartIdx,
                              BG.EndIdx, InstCnt);
      else
        Res = SelectRotMaskIns64(Res, BG.V, dl, BG.RLAmt, BG.Repl32,
                                 BG.StartIdx, BG.EndIdx, InstCnt);
    }
 
    if (LateMask) {
      uint64_t Mask = getZerosMask();
 
      // We can use the 32-bit andi/andis technique if the mask does not
      // require any higher-order bits. This can save an instruction compared
      // to always using the general 64-bit technique.
      bool Use32BitInsts = isUInt<32>(Mask);
      // Compute the masks for andi/andis that would be necessary.
      unsigned ANDIMask = (Mask & UINT16_MAX),
               ANDISMask = (Mask >> 16) & UINT16_MAX;
 
      if (Use32BitInsts) {
        assert((ANDIMask != 0 || ANDISMask != 0) &&
               "No set bits in mask when using 32-bit ands for 64-bit value");
 
        if (InstCnt) *InstCnt += (unsigned) (ANDIMask != 0) +
                                 (unsigned) (ANDISMask != 0) +
                                 (unsigned) (ANDIMask != 0 && ANDISMask != 0);
 
        SDValue ANDIVal, ANDISVal;
        if (ANDIMask != 0)
          ANDIVal = SDValue(CurDAG->getMachineNode(PPC::ANDI8_rec, dl, MVT::i64,
                                                   ExtendToInt64(Res, dl),
                                                   getI32Imm(ANDIMask, dl)),
                            0);
        if (ANDISMask != 0)
          ANDISVal =
              SDValue(CurDAG->getMachineNode(PPC::ANDIS8_rec, dl, MVT::i64,
                                             ExtendToInt64(Res, dl),
                                             getI32Imm(ANDISMask, dl)),
                      0);
 
        if (!ANDIVal)
          Res = ANDISVal;
        else if (!ANDISVal)
          Res = ANDIVal;
        else
          Res = SDValue(CurDAG->getMachineNode(PPC::OR8, dl, MVT::i64,
                          ExtendToInt64(ANDIVal, dl), ANDISVal), 0);
      } else {
        unsigned NumOfSelectInsts = 0;
        SDValue MaskVal =
            SDValue(selectI64Imm(CurDAG, dl, Mask, &NumOfSelectInsts), 0);
        Res = SDValue(CurDAG->getMachineNode(PPC::AND8, dl, MVT::i64,
                                             ExtendToInt64(Res, dl), MaskVal),
                      0);
        if (InstCnt)
          *InstCnt += NumOfSelectInsts + /* and */ 1;
      }
    }
 
    return Res.getNode();
  }
 
  SDNode *Select(SDNode *N, bool LateMask, unsigned *InstCnt = nullptr) {
    // Fill in BitGroups.
    collectBitGroups(LateMask);
    if (BitGroups.empty())
      return nullptr;
 
    // For 64-bit values, figure out when we can use 32-bit instructions.
    if (Bits.size() == 64)
      assignRepl32BitGroups();
 
    // Fill in ValueRotsVec.
    collectValueRotInfo();
 
    if (Bits.size() == 32) {
      return Select32(N, LateMask, InstCnt);
    } else {
      assert(Bits.size() == 64 && "Not 64 bits here?");
      return Select64(N, LateMask, InstCnt);
    }
 
    return nullptr;
  }
 
  void eraseMatchingBitGroups(function_ref<bool(const BitGroup &)> F) {
    erase_if(BitGroups, F);
  }
 
  SmallVector<ValueBit, 64> Bits;
 
  bool NeedMask = false;
  SmallVector<unsigned, 64> RLAmt;
 
  SmallVector<BitGroup, 16> BitGroups;
 
  DenseMap<std::pair<SDValue, unsigned>, ValueRotInfo> ValueRots;
  SmallVector<ValueRotInfo, 16> ValueRotsVec;
 
  SelectionDAG *CurDAG = nullptr;
 
public:
  BitPermutationSelector(SelectionDAG *DAG)
    : CurDAG(DAG) {}
 
  // Here we try to match complex bit permutations into a set of
  // rotate-and-shift/shift/and/or instructions, using a set of heuristics
  // known to produce optimal code for common cases (like i32 byte swapping).
  SDNode *Select(SDNode *N) {
    Memoizer.clear();
    auto Result =
        getValueBits(SDValue(N, 0), N->getValueType(0).getSizeInBits());
    if (!Result.first)
      return nullptr;
    Bits = std::move(*Result.second);
 
    LLVM_DEBUG(dbgs() << "Considering bit-permutation-based instruction"
                         " selection for:    ");
    LLVM_DEBUG(N->dump(CurDAG));
 
    // Fill it RLAmt and set NeedMask.
    computeRotationAmounts();
 
    if (!NeedMask)
      return Select(N, false);
 
    // We currently have two techniques for handling results with zeros: early
    // masking (the default) and late masking. Late masking is sometimes more
    // efficient, but because the structure of the bit groups is different, it
    // is hard to tell without generating both and comparing the results. With
    // late masking, we ignore zeros in the resulting value when inserting each
    // set of bit groups, and then mask in the zeros at the end. With early
    // masking, we only insert the non-zero parts of the result at every step.
 
    unsigned InstCnt = 0, InstCntLateMask = 0;
    LLVM_DEBUG(dbgs() << "\tEarly masking:\n");
    SDNode *RN = Select(N, false, &InstCnt);
    LLVM_DEBUG(dbgs() << "\t\tisel would use " << InstCnt << " instructions\n");
 
    LLVM_DEBUG(dbgs() << "\tLate masking:\n");
    SDNode *RNLM = Select(N, true, &InstCntLateMask);
    LLVM_DEBUG(dbgs() << "\t\tisel would use " << InstCntLateMask
                      << " instructions\n");
 
    if (InstCnt <= InstCntLateMask) {
      LLVM_DEBUG(dbgs() << "\tUsing early-masking for isel\n");
      return RN;
    }
 
    LLVM_DEBUG(dbgs() << "\tUsing late-masking for isel\n");
    return RNLM;
  }
};
 
class IntegerCompareEliminator {
  SelectionDAG *CurDAG;
  PPCDAGToDAGISel *S;
  // Conversion type for interpreting results of a 32-bit instruction as
  // a 64-bit value or vice versa.
  enum ExtOrTruncConversion { Ext, Trunc };
 
  // Modifiers to guide how an ISD::SETCC node's result is to be computed
  // in a GPR.
  // ZExtOrig - use the original condition code, zero-extend value
  // ZExtInvert - invert the condition code, zero-extend value
  // SExtOrig - use the original condition code, sign-extend value
  // SExtInvert - invert the condition code, sign-extend value
  enum SetccInGPROpts { ZExtOrig, ZExtInvert, SExtOrig, SExtInvert };
 
  // Comparisons against zero to emit GPR code sequences for. Each of these
  // sequences may need to be emitted for two or more equivalent patterns.
  // For example (a >= 0) == (a > -1). The direction of the comparison (</>)
  // matters as well as the extension type: sext (-1/0), zext (1/0).
  // GEZExt - (zext (LHS >= 0))
  // GESExt - (sext (LHS >= 0))
  // LEZExt - (zext (LHS <= 0))
  // LESExt - (sext (LHS <= 0))
  enum ZeroCompare { GEZExt, GESExt, LEZExt, LESExt };
 
  SDNode *tryEXTEND(SDNode *N);
  SDNode *tryLogicOpOfCompares(SDNode *N);
  SDValue computeLogicOpInGPR(SDValue LogicOp);
  SDValue signExtendInputIfNeeded(SDValue Input);
  SDValue zeroExtendInputIfNeeded(SDValue Input);
  SDValue addExtOrTrunc(SDValue NatWidthRes, ExtOrTruncConversion Conv);
  SDValue getCompoundZeroComparisonInGPR(SDValue LHS, SDLoc dl,
                                        ZeroCompare CmpTy);
  SDValue get32BitZExtCompare(SDValue LHS, SDValue RHS, ISD::CondCode CC,
                              int64_t RHSValue, SDLoc dl);
 SDValue get32BitSExtCompare(SDValue LHS, SDValue RHS, ISD::CondCode CC,
                              int64_t RHSValue, SDLoc dl);
  SDValue get64BitZExtCompare(SDValue LHS, SDValue RHS, ISD::CondCode CC,
                              int64_t RHSValue, SDLoc dl);
  SDValue get64BitSExtCompare(SDValue LHS, SDValue RHS, ISD::CondCode CC,
                              int64_t RHSValue, SDLoc dl);
  SDValue getSETCCInGPR(SDValue Compare, SetccInGPROpts ConvOpts);
 
public:
  IntegerCompareEliminator(SelectionDAG *DAG,
                           PPCDAGToDAGISel *Sel) : CurDAG(DAG), S(Sel) {
    assert(CurDAG->getTargetLoweringInfo()
           .getPointerTy(CurDAG->getDataLayout()).getSizeInBits() == 64 &&
           "Only expecting to use this on 64 bit targets.");
  }
  SDNode *Select(SDNode *N) {
    if (CmpInGPR == ICGPR_None)
      return nullptr;
    switch (N->getOpcode()) {
    default: break;
    case ISD::ZERO_EXTEND:
      if (CmpInGPR == ICGPR_Sext || CmpInGPR == ICGPR_SextI32 ||
          CmpInGPR == ICGPR_SextI64)
        return nullptr;
      [[fallthrough]];
    case ISD::SIGN_EXTEND:
      if (CmpInGPR == ICGPR_Zext || CmpInGPR == ICGPR_ZextI32 ||
          CmpInGPR == ICGPR_ZextI64)
        return nullptr;
      return tryEXTEND(N);
    case ISD::AND:
    case ISD::OR:
    case ISD::XOR:
      return tryLogicOpOfCompares(N);
    }
    return nullptr;
  }
};
 
static bool isLogicOp(unsigned Opc) {
  return Opc == ISD::AND || Opc == ISD::OR || Opc == ISD::XOR;
}
// The obvious case for wanting to keep the value in a GPR. Namely, the
// result of the comparison is actually needed in a GPR.
SDNode *IntegerCompareEliminator::tryEXTEND(SDNode *N) {
  assert((N->getOpcode() == ISD::ZERO_EXTEND ||
          N->getOpcode() == ISD::SIGN_EXTEND) &&
         "Expecting a zero/sign extend node!");
  SDValue WideRes;
  // If we are zero-extending the result of a logical operation on i1
  // values, we can keep the values in GPRs.
  if (isLogicOp(N->getOperand(0).getOpcode()) &&
      N->getOperand(0).getValueType() == MVT::i1 &&
      N->getOpcode() == ISD::ZERO_EXTEND)
    WideRes = computeLogicOpInGPR(N->getOperand(0));
  else if (N->getOperand(0).getOpcode() != ISD::SETCC)
    return nullptr;
  else
    WideRes =
      getSETCCInGPR(N->getOperand(0),
                    N->getOpcode() == ISD::SIGN_EXTEND ?
                    SetccInGPROpts::SExtOrig : SetccInGPROpts::ZExtOrig);
 
  if (!WideRes)
    return nullptr;
 
  SDLoc dl(N);
  bool Input32Bit = WideRes.getValueType() == MVT::i32;
  bool Output32Bit = N->getValueType(0) == MVT::i32;
 
  NumSextSetcc += N->getOpcode() == ISD::SIGN_EXTEND ? 1 : 0;
  NumZextSetcc += N->getOpcode() == ISD::SIGN_EXTEND ? 0 : 1;
 
  SDValue ConvOp = WideRes;
  if (Input32Bit != Output32Bit)
    ConvOp = addExtOrTrunc(WideRes, Input32Bit ? ExtOrTruncConversion::Ext :
                           ExtOrTruncConversion::Trunc);
  return ConvOp.getNode();
}
 
// Attempt to perform logical operations on the results of comparisons while
// keeping the values in GPRs. Without doing so, these would end up being
// lowered to CR-logical operations which suffer from significant latency and
// low ILP.
SDNode *IntegerCompareEliminator::tryLogicOpOfCompares(SDNode *N) {
  if (N->getValueType(0) != MVT::i1)
    return nullptr;
  assert(isLogicOp(N->getOpcode()) &&
         "Expected a logic operation on setcc results.");
  SDValue LoweredLogical = computeLogicOpInGPR(SDValue(N, 0));
  if (!LoweredLogical)
    return nullptr;
 
  SDLoc dl(N);
  bool IsBitwiseNegate = LoweredLogical.getMachineOpcode() == PPC::XORI8;
  unsigned SubRegToExtract = IsBitwiseNegate ? PPC::sub_eq : PPC::sub_gt;
  SDValue CR0Reg = CurDAG->getRegister(PPC::CR0, MVT::i32);
  SDValue LHS = LoweredLogical.getOperand(0);
  SDValue RHS = LoweredLogical.getOperand(1);
  SDValue WideOp;
  SDValue OpToConvToRecForm;
 
  // Look through any 32-bit to 64-bit implicit extend nodes to find the
  // opcode that is input to the XORI.
  if (IsBitwiseNegate &&
      LoweredLogical.getOperand(0).getMachineOpcode() == PPC::INSERT_SUBREG)
    OpToConvToRecForm = LoweredLogical.getOperand(0).getOperand(1);
  else if (IsBitwiseNegate)
    // If the input to the XORI isn't an extension, that's what we're after.
    OpToConvToRecForm = LoweredLogical.getOperand(0);
  else
    // If this is not an XORI, it is a reg-reg logical op and we can convert
    // it to record-form.
    OpToConvToRecForm = LoweredLogical;
 
  // Get the record-form version of the node we're looking to use to get the
  // CR result from.
  uint16_t NonRecOpc = OpToConvToRecForm.getMachineOpcode();
  int NewOpc = PPCInstrInfo::getRecordFormOpcode(NonRecOpc);
 
  // Convert the right node to record-form. This is either the logical we're
  // looking at or it is the input node to the negation (if we're looking at
  // a bitwise negation).
  if (NewOpc != -1 && IsBitwiseNegate) {
    // The input to the XORI has a record-form. Use it.
    assert(LoweredLogical.getConstantOperandVal(1) == 1 &&
           "Expected a PPC::XORI8 only for bitwise negation.");
    // Emit the record-form instruction.
    std::vector<SDValue> Ops;
    for (int i = 0, e = OpToConvToRecForm.getNumOperands(); i < e; i++)
      Ops.push_back(OpToConvToRecForm.getOperand(i));
 
    WideOp =
      SDValue(CurDAG->getMachineNode(NewOpc, dl,
                                     OpToConvToRecForm.getValueType(),
                                     MVT::Glue, Ops), 0);
  } else {
    assert((NewOpc != -1 || !IsBitwiseNegate) &&
           "No record form available for AND8/OR8/XOR8?");
    WideOp =
        SDValue(CurDAG->getMachineNode(NewOpc == -1 ? PPC::ANDI8_rec : NewOpc,
                                       dl, MVT::i64, MVT::Glue, LHS, RHS),
                0);
  }
 
  // Select this node to a single bit from CR0 set by the record-form node
  // just created. For bitwise negation, use the EQ bit which is the equivalent
  // of negating the result (i.e. it is a bit set when the result of the
  // operation is zero).
  SDValue SRIdxVal =
    CurDAG->getTargetConstant(SubRegToExtract, dl, MVT::i32);
  SDValue CRBit =
    SDValue(CurDAG->getMachineNode(TargetOpcode::EXTRACT_SUBREG, dl,
                                   MVT::i1, CR0Reg, SRIdxVal,
                                   WideOp.getValue(1)), 0);
  return CRBit.getNode();
}
 
// Lower a logical operation on i1 values into a GPR sequence if possible.
// The result can be kept in a GPR if requested.
// Three types of inputs can be handled:
// - SETCC
// - TRUNCATE
// - Logical operation (AND/OR/XOR)
// There is also a special case that is handled (namely a complement operation
// achieved with xor %a, -1).
SDValue IntegerCompareEliminator::computeLogicOpInGPR(SDValue LogicOp) {
  assert(isLogicOp(LogicOp.getOpcode()) &&
        "Can only handle logic operations here.");
  assert(LogicOp.getValueType() == MVT::i1 &&
         "Can only handle logic operations on i1 values here.");
  SDLoc dl(LogicOp);
  SDValue LHS, RHS;
 
 // Special case: xor %a, -1
  bool IsBitwiseNegation = isBitwiseNot(LogicOp);
 
  // Produces a GPR sequence for each operand of the binary logic operation.
  // For SETCC, it produces the respective comparison, for TRUNCATE it truncates
  // the value in a GPR and for logic operations, it will recursively produce
  // a GPR sequence for the operation.
 auto getLogicOperand = [&] (SDValue Operand) -> SDValue {
    unsigned OperandOpcode = Operand.getOpcode();
    if (OperandOpcode == ISD::SETCC)
      return getSETCCInGPR(Operand, SetccInGPROpts::ZExtOrig);
    else if (OperandOpcode == ISD::TRUNCATE) {
      SDValue InputOp = Operand.getOperand(0);
     EVT InVT = InputOp.getValueType();
      return SDValue(CurDAG->getMachineNode(InVT == MVT::i32 ? PPC::RLDICL_32 :
                                            PPC::RLDICL, dl, InVT, InputOp,
                                            S->getI64Imm(0, dl),
                                            S->getI64Imm(63, dl)), 0);
    } else if (isLogicOp(OperandOpcode))
      return computeLogicOpInGPR(Operand);
    return SDValue();
  };
  LHS = getLogicOperand(LogicOp.getOperand(0));
  RHS = getLogicOperand(LogicOp.getOperand(1));
 
  // If a GPR sequence can't be produced for the LHS we can't proceed.
  // Not producing a GPR sequence for the RHS is only a problem if this isn't
  // a bitwise negation operation.
  if (!LHS || (!RHS && !IsBitwiseNegation))
    return SDValue();
 
  NumLogicOpsOnComparison++;
 
  // We will use the inputs as 64-bit values.
  if (LHS.getValueType() == MVT::i32)
    LHS = addExtOrTrunc(LHS, ExtOrTruncConversion::Ext);
  if (!IsBitwiseNegation && RHS.getValueType() == MVT::i32)
    RHS = addExtOrTrunc(RHS, ExtOrTruncConversion::Ext);
 
  unsigned NewOpc;
  switch (LogicOp.getOpcode()) {
  default: llvm_unreachable("Unknown logic operation.");
  case ISD::AND: NewOpc = PPC::AND8; break;
  case ISD::OR:  NewOpc = PPC::OR8;  break;
  case ISD::XOR: NewOpc = PPC::XOR8; break;
  }
 
  if (IsBitwiseNegation) {
    RHS = S->getI64Imm(1, dl);
    NewOpc = PPC::XORI8;
  }
 
  return SDValue(CurDAG->getMachineNode(NewOpc, dl, MVT::i64, LHS, RHS), 0);
 
}
 
/// If the value isn't guaranteed to be sign-extended to 64-bits, extend it.
/// Otherwise just reinterpret it as a 64-bit value.
/// Useful when emitting comparison code for 32-bit values without using
/// the compare instruction (which only considers the lower 32-bits).
SDValue IntegerCompareEliminator::signExtendInputIfNeeded(SDValue Input) {
  assert(Input.getValueType() == MVT::i32 &&
         "Can only sign-extend 32-bit values here.");
  unsigned Opc = Input.getOpcode();
 
  // The value was sign extended and then truncated to 32-bits. No need to
  // sign extend it again.
  if (Opc == ISD::TRUNCATE &&
      (Input.getOperand(0).getOpcode() == ISD::AssertSext ||
       Input.getOperand(0).getOpcode() == ISD::SIGN_EXTEND))
    return addExtOrTrunc(Input, ExtOrTruncConversion::Ext);
 
  LoadSDNode *InputLoad = dyn_cast<LoadSDNode>(Input);
  // The input is a sign-extending load. All ppc sign-extending loads
  // sign-extend to the full 64-bits.
  if (InputLoad && InputLoad->getExtensionType() == ISD::SEXTLOAD)
    return addExtOrTrunc(Input, ExtOrTruncConversion::Ext);
 
  ConstantSDNode *InputConst = dyn_cast<ConstantSDNode>(Input);
  // We don't sign-extend constants.
  if (InputConst)
    return addExtOrTrunc(Input, ExtOrTruncConversion::Ext);
 
  SDLoc dl(Input);
  SignExtensionsAdded++;
  return SDValue(CurDAG->getMachineNode(PPC::EXTSW_32_64, dl,
                                        MVT::i64, Input), 0);
}
 
/// If the value isn't guaranteed to be zero-extended to 64-bits, extend it.
/// Otherwise just reinterpret it as a 64-bit value.
/// Useful when emitting comparison code for 32-bit values without using
/// the compare instruction (which only considers the lower 32-bits).
SDValue IntegerCompareEliminator::zeroExtendInputIfNeeded(SDValue Input) {
  assert(Input.getValueType() == MVT::i32 &&
         "Can only zero-extend 32-bit values here.");
  unsigned Opc = Input.getOpcode();
 
  // The only condition under which we can omit the actual extend instruction:
  // - The value is a positive constant
  // - The value comes from a load that isn't a sign-extending load
  // An ISD::TRUNCATE needs to be zero-extended unless it is fed by a zext.
  bool IsTruncateOfZExt = Opc == ISD::TRUNCATE &&
    (Input.getOperand(0).getOpcode() == ISD::AssertZext ||
     Input.getOperand(0).getOpcode() == ISD::ZERO_EXTEND);
  if (IsTruncateOfZExt)
    return addExtOrTrunc(Input, ExtOrTruncConversion::Ext);
 
  ConstantSDNode *InputConst = dyn_cast<ConstantSDNode>(Input);
  if (InputConst && InputConst->getSExtValue() >= 0)
    return addExtOrTrunc(Input, ExtOrTruncConversion::Ext);
 
  LoadSDNode *InputLoad = dyn_cast<LoadSDNode>(Input);
  // The input is a load that doesn't sign-extend (it will be zero-extended).
  if (InputLoad && InputLoad->getExtensionType() != ISD::SEXTLOAD)
    return addExtOrTrunc(Input, ExtOrTruncConversion::Ext);
 
  // None of the above, need to zero-extend.
  SDLoc dl(Input);
  ZeroExtensionsAdded++;
  return SDValue(CurDAG->getMachineNode(PPC::RLDICL_32_64, dl, MVT::i64, Input,
                                        S->getI64Imm(0, dl),
                                        S->getI64Imm(32, dl)), 0);
}
 
// Handle a 32-bit value in a 64-bit register and vice-versa. These are of
// course not actual zero/sign extensions that will generate machine code,
// they're just a way to reinterpret a 32 bit value in a register as a
// 64 bit value and vice-versa.
SDValue IntegerCompareEliminator::addExtOrTrunc(SDValue NatWidthRes,
                                                ExtOrTruncConversion Conv) {
  SDLoc dl(NatWidthRes);
 
  // For reinterpreting 32-bit values as 64 bit values, we generate
  // INSERT_SUBREG IMPLICIT_DEF:i64, <input>, TargetConstant:i32<1>
  if (Conv == ExtOrTruncConversion::Ext) {
    SDValue ImDef(CurDAG->getMachineNode(PPC::IMPLICIT_DEF, dl, MVT::i64), 0);
    SDValue SubRegIdx =
      CurDAG->getTargetConstant(PPC::sub_32, dl, MVT::i32);
    return SDValue(CurDAG->getMachineNode(PPC::INSERT_SUBREG, dl, MVT::i64,
                                          ImDef, NatWidthRes, SubRegIdx), 0);
  }
 
  assert(Conv == ExtOrTruncConversion::Trunc &&
         "Unknown convertion between 32 and 64 bit values.");
  // For reinterpreting 64-bit values as 32-bit values, we just need to
  // EXTRACT_SUBREG (i.e. extract the low word).
  SDValue SubRegIdx =
    CurDAG->getTargetConstant(PPC::sub_32, dl, MVT::i32);
  return SDValue(CurDAG->getMachineNode(PPC::EXTRACT_SUBREG, dl, MVT::i32,
                                        NatWidthRes, SubRegIdx), 0);
}
 
// Produce a GPR sequence for compound comparisons (<=, >=) against zero.
// Handle both zero-extensions and sign-extensions.
SDValue
IntegerCompareEliminator::getCompoundZeroComparisonInGPR(SDValue LHS, SDLoc dl,
                                                         ZeroCompare CmpTy) {
  EVT InVT = LHS.getValueType();
  bool Is32Bit = InVT == MVT::i32;
  SDValue ToExtend;
 
  // Produce the value that needs to be either zero or sign extended.
  switch (CmpTy) {
  case ZeroCompare::GEZExt:
  case ZeroCompare::GESExt:
    ToExtend = SDValue(CurDAG->getMachineNode(Is32Bit ? PPC::NOR : PPC::NOR8,
                                              dl, InVT, LHS, LHS), 0);
    break;
  case ZeroCompare::LEZExt:
  case ZeroCompare::LESExt: {
    if (Is32Bit) {
      // Upper 32 bits cannot be undefined for this sequence.
      LHS = signExtendInputIfNeeded(LHS);
      SDValue Neg =
        SDValue(CurDAG->getMachineNode(PPC::NEG8, dl, MVT::i64, LHS), 0);
      ToExtend =
        SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64,
                                       Neg, S->getI64Imm(1, dl),
                                       S->getI64Imm(63, dl)), 0);
    } else {
      SDValue Addi =
        SDValue(CurDAG->getMachineNode(PPC::ADDI8, dl, MVT::i64, LHS,
                                       S->getI64Imm(~0ULL, dl)), 0);
      ToExtend = SDValue(CurDAG->getMachineNode(PPC::OR8, dl, MVT::i64,
                                                Addi, LHS), 0);
    }
    break;
  }
  }
 
  // For 64-bit sequences, the extensions are the same for the GE/LE cases.
  if (!Is32Bit &&
      (CmpTy == ZeroCompare::GEZExt || CmpTy == ZeroCompare::LEZExt))
    return SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64,
                                          ToExtend, S->getI64Imm(1, dl),
                                          S->getI64Imm(63, dl)), 0);
  if (!Is32Bit &&
      (CmpTy == ZeroCompare::GESExt || CmpTy == ZeroCompare::LESExt))
    return SDValue(CurDAG->getMachineNode(PPC::SRADI, dl, MVT::i64, ToExtend,
                                          S->getI64Imm(63, dl)), 0);
 
  assert(Is32Bit && "Should have handled the 32-bit sequences above.");
  // For 32-bit sequences, the extensions differ between GE/LE cases.
  switch (CmpTy) {
  case ZeroCompare::GEZExt: {
    SDValue ShiftOps[] = { ToExtend, S->getI32Imm(1, dl), S->getI32Imm(31, dl),
                           S->getI32Imm(31, dl) };
    return SDValue(CurDAG->getMachineNode(PPC::RLWINM, dl, MVT::i32,
                                          ShiftOps), 0);
  }
  case ZeroCompare::GESExt:
    return SDValue(CurDAG->getMachineNode(PPC::SRAWI, dl, MVT::i32, ToExtend,
                                          S->getI32Imm(31, dl)), 0);
  case ZeroCompare::LEZExt:
    return SDValue(CurDAG->getMachineNode(PPC::XORI8, dl, MVT::i64, ToExtend,
                                          S->getI32Imm(1, dl)), 0);
  case ZeroCompare::LESExt:
    return SDValue(CurDAG->getMachineNode(PPC::ADDI8, dl, MVT::i64, ToExtend,
                                          S->getI32Imm(-1, dl)), 0);
  }
 
  // The above case covers all the enumerators so it can't have a default clause
  // to avoid compiler warnings.
  llvm_unreachable("Unknown zero-comparison type.");
}
 
/// Produces a zero-extended result of comparing two 32-bit values according to
/// the passed condition code.
SDValue
IntegerCompareEliminator::get32BitZExtCompare(SDValue LHS, SDValue RHS,
                                              ISD::CondCode CC,
                                              int64_t RHSValue, SDLoc dl) {
  if (CmpInGPR == ICGPR_I64 || CmpInGPR == ICGPR_SextI64 ||
      CmpInGPR == ICGPR_ZextI64 || CmpInGPR == ICGPR_Sext)
    return SDValue();
  bool IsRHSZero = RHSValue == 0;
  bool IsRHSOne = RHSValue == 1;
  bool IsRHSNegOne = RHSValue == -1LL;
  switch (CC) {
  default: return SDValue();
  case ISD::SETEQ: {
    // (zext (setcc %a, %b, seteq)) -> (lshr (cntlzw (xor %a, %b)), 5)
    // (zext (setcc %a, 0, seteq))  -> (lshr (cntlzw %a), 5)
    SDValue Xor = IsRHSZero ? LHS :
      SDValue(CurDAG->getMachineNode(PPC::XOR, dl, MVT::i32, LHS, RHS), 0);
    SDValue Clz =
      SDValue(CurDAG->getMachineNode(PPC::CNTLZW, dl, MVT::i32, Xor), 0);
    SDValue ShiftOps[] = { Clz, S->getI32Imm(27, dl), S->getI32Imm(5, dl),
      S->getI32Imm(31, dl) };
    return SDValue(CurDAG->getMachineNode(PPC::RLWINM, dl, MVT::i32,
                                          ShiftOps), 0);
  }
  case ISD::SETNE: {
    // (zext (setcc %a, %b, setne)) -> (xor (lshr (cntlzw (xor %a, %b)), 5), 1)
    // (zext (setcc %a, 0, setne))  -> (xor (lshr (cntlzw %a), 5), 1)
    SDValue Xor = IsRHSZero ? LHS :
      SDValue(CurDAG->getMachineNode(PPC::XOR, dl, MVT::i32, LHS, RHS), 0);
    SDValue Clz =
      SDValue(CurDAG->getMachineNode(PPC::CNTLZW, dl, MVT::i32, Xor), 0);
    SDValue ShiftOps[] = { Clz, S->getI32Imm(27, dl), S->getI32Imm(5, dl),
      S->getI32Imm(31, dl) };
    SDValue Shift =
      SDValue(CurDAG->getMachineNode(PPC::RLWINM, dl, MVT::i32, ShiftOps), 0);
    return SDValue(CurDAG->getMachineNode(PPC::XORI, dl, MVT::i32, Shift,
                                          S->getI32Imm(1, dl)), 0);
  }
  case ISD::SETGE: {
    // (zext (setcc %a, %b, setge)) -> (xor (lshr (sub %a, %b), 63), 1)
    // (zext (setcc %a, 0, setge))  -> (lshr (~ %a), 31)
    if(IsRHSZero)
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::GEZExt);
 
    // Not a special case (i.e. RHS == 0). Handle (%a >= %b) as (%b <= %a)
    // by swapping inputs and falling through.
    std::swap(LHS, RHS);
    ConstantSDNode *RHSConst = dyn_cast<ConstantSDNode>(RHS);
    IsRHSZero = RHSConst && RHSConst->isZero();
    [[fallthrough]];
  }
  case ISD::SETLE: {
    if (CmpInGPR == ICGPR_NonExtIn)
      return SDValue();
    // (zext (setcc %a, %b, setle)) -> (xor (lshr (sub %b, %a), 63), 1)
    // (zext (setcc %a, 0, setle))  -> (xor (lshr (- %a), 63), 1)
    if(IsRHSZero) {
      if (CmpInGPR == ICGPR_NonExtIn)
        return SDValue();
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::LEZExt);
    }
 
    // The upper 32-bits of the register can't be undefined for this sequence.
    LHS = signExtendInputIfNeeded(LHS);
    RHS = signExtendInputIfNeeded(RHS);
    SDValue Sub =
      SDValue(CurDAG->getMachineNode(PPC::SUBF8, dl, MVT::i64, LHS, RHS), 0);
    SDValue Shift =
      SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, Sub,
                                     S->getI64Imm(1, dl), S->getI64Imm(63, dl)),
              0);
    return
      SDValue(CurDAG->getMachineNode(PPC::XORI8, dl,
                                     MVT::i64, Shift, S->getI32Imm(1, dl)), 0);
  }
  case ISD::SETGT: {
    // (zext (setcc %a, %b, setgt)) -> (lshr (sub %b, %a), 63)
    // (zext (setcc %a, -1, setgt)) -> (lshr (~ %a), 31)
    // (zext (setcc %a, 0, setgt))  -> (lshr (- %a), 63)
    // Handle SETLT -1 (which is equivalent to SETGE 0).
    if (IsRHSNegOne)
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::GEZExt);
 
    if (IsRHSZero) {
      if (CmpInGPR == ICGPR_NonExtIn)
        return SDValue();
      // The upper 32-bits of the register can't be undefined for this sequence.
      LHS = signExtendInputIfNeeded(LHS);
      RHS = signExtendInputIfNeeded(RHS);
      SDValue Neg =
        SDValue(CurDAG->getMachineNode(PPC::NEG8, dl, MVT::i64, LHS), 0);
      return SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64,
                     Neg, S->getI32Imm(1, dl), S->getI32Imm(63, dl)), 0);
    }
    // Not a special case (i.e. RHS == 0 or RHS == -1). Handle (%a > %b) as
    // (%b < %a) by swapping inputs and falling through.
    std::swap(LHS, RHS);
    ConstantSDNode *RHSConst = dyn_cast<ConstantSDNode>(RHS);
    IsRHSZero = RHSConst && RHSConst->isZero();
    IsRHSOne = RHSConst && RHSConst->getSExtValue() == 1;
    [[fallthrough]];
  }
  case ISD::SETLT: {
    // (zext (setcc %a, %b, setlt)) -> (lshr (sub %a, %b), 63)
    // (zext (setcc %a, 1, setlt))  -> (xor (lshr (- %a), 63), 1)
    // (zext (setcc %a, 0, setlt))  -> (lshr %a, 31)
    // Handle SETLT 1 (which is equivalent to SETLE 0).
    if (IsRHSOne) {
      if (CmpInGPR == ICGPR_NonExtIn)
        return SDValue();
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::LEZExt);
    }
 
    if (IsRHSZero) {
      SDValue ShiftOps[] = { LHS, S->getI32Imm(1, dl), S->getI32Imm(31, dl),
                             S->getI32Imm(31, dl) };
      return SDValue(CurDAG->getMachineNode(PPC::RLWINM, dl, MVT::i32,
                                            ShiftOps), 0);
    }
 
    if (CmpInGPR == ICGPR_NonExtIn)
      return SDValue();
    // The upper 32-bits of the register can't be undefined for this sequence.
    LHS = signExtendInputIfNeeded(LHS);
    RHS = signExtendInputIfNeeded(RHS);
    SDValue SUBFNode =
      SDValue(CurDAG->getMachineNode(PPC::SUBF8, dl, MVT::i64, RHS, LHS), 0);
    return SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64,
                                    SUBFNode, S->getI64Imm(1, dl),
                                    S->getI64Imm(63, dl)), 0);
  }
  case ISD::SETUGE:
    // (zext (setcc %a, %b, setuge)) -> (xor (lshr (sub %b, %a), 63), 1)
    // (zext (setcc %a, %b, setule)) -> (xor (lshr (sub %a, %b), 63), 1)
    std::swap(LHS, RHS);
    [[fallthrough]];
  case ISD::SETULE: {
    if (CmpInGPR == ICGPR_NonExtIn)
      return SDValue();
    // The upper 32-bits of the register can't be undefined for this sequence.
    LHS = zeroExtendInputIfNeeded(LHS);
    RHS = zeroExtendInputIfNeeded(RHS);
    SDValue Subtract =
      SDValue(CurDAG->getMachineNode(PPC::SUBF8, dl, MVT::i64, LHS, RHS), 0);
    SDValue SrdiNode =
      SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64,
                                          Subtract, S->getI64Imm(1, dl),
                                          S->getI64Imm(63, dl)), 0);
    return SDValue(CurDAG->getMachineNode(PPC::XORI8, dl, MVT::i64, SrdiNode,
                                            S->getI32Imm(1, dl)), 0);
  }
  case ISD::SETUGT:
    // (zext (setcc %a, %b, setugt)) -> (lshr (sub %b, %a), 63)
    // (zext (setcc %a, %b, setult)) -> (lshr (sub %a, %b), 63)
    std::swap(LHS, RHS);
    [[fallthrough]];
  case ISD::SETULT: {
    if (CmpInGPR == ICGPR_NonExtIn)
      return SDValue();
    // The upper 32-bits of the register can't be undefined for this sequence.
    LHS = zeroExtendInputIfNeeded(LHS);
    RHS = zeroExtendInputIfNeeded(RHS);
    SDValue Subtract =
      SDValue(CurDAG->getMachineNode(PPC::SUBF8, dl, MVT::i64, RHS, LHS), 0);
    return SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64,
                                          Subtract, S->getI64Imm(1, dl),
                                          S->getI64Imm(63, dl)), 0);
  }
  }
}
 
/// Produces a sign-extended result of comparing two 32-bit values according to
/// the passed condition code.
SDValue
IntegerCompareEliminator::get32BitSExtCompare(SDValue LHS, SDValue RHS,
                                              ISD::CondCode CC,
                                              int64_t RHSValue, SDLoc dl) {
  if (CmpInGPR == ICGPR_I64 || CmpInGPR == ICGPR_SextI64 ||
      CmpInGPR == ICGPR_ZextI64 || CmpInGPR == ICGPR_Zext)
    return SDValue();
  bool IsRHSZero = RHSValue == 0;
  bool IsRHSOne = RHSValue == 1;
  bool IsRHSNegOne = RHSValue == -1LL;
 
  switch (CC) {
  default: return SDValue();
  case ISD::SETEQ: {
    // (sext (setcc %a, %b, seteq)) ->
    //   (ashr (shl (ctlz (xor %a, %b)), 58), 63)
    // (sext (setcc %a, 0, seteq)) ->
    //   (ashr (shl (ctlz %a), 58), 63)
    SDValue CountInput = IsRHSZero ? LHS :
      SDValue(CurDAG->getMachineNode(PPC::XOR, dl, MVT::i32, LHS, RHS), 0);
    SDValue Cntlzw =
      SDValue(CurDAG->getMachineNode(PPC::CNTLZW, dl, MVT::i32, CountInput), 0);
    SDValue SHLOps[] = { Cntlzw, S->getI32Imm(27, dl),
                         S->getI32Imm(5, dl), S->getI32Imm(31, dl) };
    SDValue Slwi =
      SDValue(CurDAG->getMachineNode(PPC::RLWINM, dl, MVT::i32, SHLOps), 0);
    return SDValue(CurDAG->getMachineNode(PPC::NEG, dl, MVT::i32, Slwi), 0);
  }
  case ISD::SETNE: {
    // Bitwise xor the operands, count leading zeros, shift right by 5 bits and
    // flip the bit, finally take 2's complement.
    // (sext (setcc %a, %b, setne)) ->
    //   (neg (xor (lshr (ctlz (xor %a, %b)), 5), 1))
    // Same as above, but the first xor is not needed.
    // (sext (setcc %a, 0, setne)) ->
    //   (neg (xor (lshr (ctlz %a), 5), 1))
    SDValue Xor = IsRHSZero ? LHS :
      SDValue(CurDAG->getMachineNode(PPC::XOR, dl, MVT::i32, LHS, RHS), 0);
    SDValue Clz =
      SDValue(CurDAG->getMachineNode(PPC::CNTLZW, dl, MVT::i32, Xor), 0);
    SDValue ShiftOps[] =
      { Clz, S->getI32Imm(27, dl), S->getI32Imm(5, dl), S->getI32Imm(31, dl) };
    SDValue Shift =
      SDValue(CurDAG->getMachineNode(PPC::RLWINM, dl, MVT::i32, ShiftOps), 0);
    SDValue Xori =
      SDValue(CurDAG->getMachineNode(PPC::XORI, dl, MVT::i32, Shift,
                                     S->getI32Imm(1, dl)), 0);
    return SDValue(CurDAG->getMachineNode(PPC::NEG, dl, MVT::i32, Xori), 0);
  }
  case ISD::SETGE: {
    // (sext (setcc %a, %b, setge)) -> (add (lshr (sub %a, %b), 63), -1)
    // (sext (setcc %a, 0, setge))  -> (ashr (~ %a), 31)
    if (IsRHSZero)
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::GESExt);
 
    // Not a special case (i.e. RHS == 0). Handle (%a >= %b) as (%b <= %a)
    // by swapping inputs and falling through.
    std::swap(LHS, RHS);
    ConstantSDNode *RHSConst = dyn_cast<ConstantSDNode>(RHS);
    IsRHSZero = RHSConst && RHSConst->isZero();
    [[fallthrough]];
  }
  case ISD::SETLE: {
    if (CmpInGPR == ICGPR_NonExtIn)
      return SDValue();
    // (sext (setcc %a, %b, setge)) -> (add (lshr (sub %b, %a), 63), -1)
    // (sext (setcc %a, 0, setle))  -> (add (lshr (- %a), 63), -1)
    if (IsRHSZero)
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::LESExt);
 
    // The upper 32-bits of the register can't be undefined for this sequence.
    LHS = signExtendInputIfNeeded(LHS);
    RHS = signExtendInputIfNeeded(RHS);
    SDValue SUBFNode =
      SDValue(CurDAG->getMachineNode(PPC::SUBF8, dl, MVT::i64, MVT::Glue,
                                     LHS, RHS), 0);
    SDValue Srdi =
      SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64,
                                     SUBFNode, S->getI64Imm(1, dl),
                                     S->getI64Imm(63, dl)), 0);
    return SDValue(CurDAG->getMachineNode(PPC::ADDI8, dl, MVT::i64, Srdi,
                                          S->getI32Imm(-1, dl)), 0);
  }
  case ISD::SETGT: {
    // (sext (setcc %a, %b, setgt)) -> (ashr (sub %b, %a), 63)
    // (sext (setcc %a, -1, setgt)) -> (ashr (~ %a), 31)
    // (sext (setcc %a, 0, setgt))  -> (ashr (- %a), 63)
    if (IsRHSNegOne)
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::GESExt);
    if (IsRHSZero) {
      if (CmpInGPR == ICGPR_NonExtIn)
        return SDValue();
      // The upper 32-bits of the register can't be undefined for this sequence.
      LHS = signExtendInputIfNeeded(LHS);
      RHS = signExtendInputIfNeeded(RHS);
      SDValue Neg =
        SDValue(CurDAG->getMachineNode(PPC::NEG8, dl, MVT::i64, LHS), 0);
        return SDValue(CurDAG->getMachineNode(PPC::SRADI, dl, MVT::i64, Neg,
                                              S->getI64Imm(63, dl)), 0);
    }
    // Not a special case (i.e. RHS == 0 or RHS == -1). Handle (%a > %b) as
    // (%b < %a) by swapping inputs and falling through.
    std::swap(LHS, RHS);
    ConstantSDNode *RHSConst = dyn_cast<ConstantSDNode>(RHS);
    IsRHSZero = RHSConst && RHSConst->isZero();
    IsRHSOne = RHSConst && RHSConst->getSExtValue() == 1;
    [[fallthrough]];
  }
  case ISD::SETLT: {
    // (sext (setcc %a, %b, setgt)) -> (ashr (sub %a, %b), 63)
    // (sext (setcc %a, 1, setgt))  -> (add (lshr (- %a), 63), -1)
    // (sext (setcc %a, 0, setgt))  -> (ashr %a, 31)
    if (IsRHSOne) {
      if (CmpInGPR == ICGPR_NonExtIn)
        return SDValue();
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::LESExt);
    }
    if (IsRHSZero)
      return SDValue(CurDAG->getMachineNode(PPC::SRAWI, dl, MVT::i32, LHS,
                                            S->getI32Imm(31, dl)), 0);
 
    if (CmpInGPR == ICGPR_NonExtIn)
      return SDValue();
    // The upper 32-bits of the register can't be undefined for this sequence.
    LHS = signExtendInputIfNeeded(LHS);
    RHS = signExtendInputIfNeeded(RHS);
    SDValue SUBFNode =
      SDValue(CurDAG->getMachineNode(PPC::SUBF8, dl, MVT::i64, RHS, LHS), 0);
    return SDValue(CurDAG->getMachineNode(PPC::SRADI, dl, MVT::i64,
                                          SUBFNode, S->getI64Imm(63, dl)), 0);
  }
  case ISD::SETUGE:
    // (sext (setcc %a, %b, setuge)) -> (add (lshr (sub %a, %b), 63), -1)
    // (sext (setcc %a, %b, setule)) -> (add (lshr (sub %b, %a), 63), -1)
    std::swap(LHS, RHS);
    [[fallthrough]];
  case ISD::SETULE: {
    if (CmpInGPR == ICGPR_NonExtIn)
      return SDValue();
    // The upper 32-bits of the register can't be undefined for this sequence.
    LHS = zeroExtendInputIfNeeded(LHS);
    RHS = zeroExtendInputIfNeeded(RHS);
    SDValue Subtract =
      SDValue(CurDAG->getMachineNode(PPC::SUBF8, dl, MVT::i64, LHS, RHS), 0);
    SDValue Shift =
      SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, Subtract,
                                     S->getI32Imm(1, dl), S->getI32Imm(63,dl)),
              0);
    return SDValue(CurDAG->getMachineNode(PPC::ADDI8, dl, MVT::i64, Shift,
                                          S->getI32Imm(-1, dl)), 0);
  }
  case ISD::SETUGT:
    // (sext (setcc %a, %b, setugt)) -> (ashr (sub %b, %a), 63)
    // (sext (setcc %a, %b, setugt)) -> (ashr (sub %a, %b), 63)
    std::swap(LHS, RHS);
    [[fallthrough]];
  case ISD::SETULT: {
    if (CmpInGPR == ICGPR_NonExtIn)
      return SDValue();
    // The upper 32-bits of the register can't be undefined for this sequence.
    LHS = zeroExtendInputIfNeeded(LHS);
    RHS = zeroExtendInputIfNeeded(RHS);
    SDValue Subtract =
      SDValue(CurDAG->getMachineNode(PPC::SUBF8, dl, MVT::i64, RHS, LHS), 0);
    return SDValue(CurDAG->getMachineNode(PPC::SRADI, dl, MVT::i64,
                                          Subtract, S->getI64Imm(63, dl)), 0);
  }
  }
}
 
/// Produces a zero-extended result of comparing two 64-bit values according to
/// the passed condition code.
SDValue
IntegerCompareEliminator::get64BitZExtCompare(SDValue LHS, SDValue RHS,
                                              ISD::CondCode CC,
                                              int64_t RHSValue, SDLoc dl) {
  if (CmpInGPR == ICGPR_I32 || CmpInGPR == ICGPR_SextI32 ||
      CmpInGPR == ICGPR_ZextI32 || CmpInGPR == ICGPR_Sext)
    return SDValue();
  bool IsRHSZero = RHSValue == 0;
  bool IsRHSOne = RHSValue == 1;
  bool IsRHSNegOne = RHSValue == -1LL;
  switch (CC) {
  default: return SDValue();
  case ISD::SETEQ: {
    // (zext (setcc %a, %b, seteq)) -> (lshr (ctlz (xor %a, %b)), 6)
    // (zext (setcc %a, 0, seteq)) ->  (lshr (ctlz %a), 6)
    SDValue Xor = IsRHSZero ? LHS :
      SDValue(CurDAG->getMachineNode(PPC::XOR8, dl, MVT::i64, LHS, RHS), 0);
    SDValue Clz =
      SDValue(CurDAG->getMachineNode(PPC::CNTLZD, dl, MVT::i64, Xor), 0);
    return SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, Clz,
                                          S->getI64Imm(58, dl),
                                          S->getI64Imm(63, dl)), 0);
  }
  case ISD::SETNE: {
    // {addc.reg, addc.CA} = (addcarry (xor %a, %b), -1)
    // (zext (setcc %a, %b, setne)) -> (sube addc.reg, addc.reg, addc.CA)
    // {addcz.reg, addcz.CA} = (addcarry %a, -1)
    // (zext (setcc %a, 0, setne)) -> (sube addcz.reg, addcz.reg, addcz.CA)
    SDValue Xor = IsRHSZero ? LHS :
      SDValue(CurDAG->getMachineNode(PPC::XOR8, dl, MVT::i64, LHS, RHS), 0);
    SDValue AC =
      SDValue(CurDAG->getMachineNode(PPC::ADDIC8, dl, MVT::i64, MVT::Glue,
                                     Xor, S->getI32Imm(~0U, dl)), 0);
    return SDValue(CurDAG->getMachineNode(PPC::SUBFE8, dl, MVT::i64, AC,
                                          Xor, AC.getValue(1)), 0);
  }
  case ISD::SETGE: {
    // {subc.reg, subc.CA} = (subcarry %a, %b)
    // (zext (setcc %a, %b, setge)) ->
    //   (adde (lshr %b, 63), (ashr %a, 63), subc.CA)
    // (zext (setcc %a, 0, setge)) -> (lshr (~ %a), 63)
    if (IsRHSZero)
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::GEZExt);
    std::swap(LHS, RHS);
    ConstantSDNode *RHSConst = dyn_cast<ConstantSDNode>(RHS);
    IsRHSZero = RHSConst && RHSConst->isZero();
    [[fallthrough]];
  }
  case ISD::SETLE: {
    // {subc.reg, subc.CA} = (subcarry %b, %a)
    // (zext (setcc %a, %b, setge)) ->
    //   (adde (lshr %a, 63), (ashr %b, 63), subc.CA)
    // (zext (setcc %a, 0, setge)) -> (lshr (or %a, (add %a, -1)), 63)
    if (IsRHSZero)
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::LEZExt);
    SDValue ShiftL =
      SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, LHS,
                                     S->getI64Imm(1, dl),
                                     S->getI64Imm(63, dl)), 0);
    SDValue ShiftR =
      SDValue(CurDAG->getMachineNode(PPC::SRADI, dl, MVT::i64, RHS,
                                     S->getI64Imm(63, dl)), 0);
    SDValue SubtractCarry =
      SDValue(CurDAG->getMachineNode(PPC::SUBFC8, dl, MVT::i64, MVT::Glue,
                                     LHS, RHS), 1);
    return SDValue(CurDAG->getMachineNode(PPC::ADDE8, dl, MVT::i64, MVT::Glue,
                                          ShiftR, ShiftL, SubtractCarry), 0);
  }
  case ISD::SETGT: {
    // {subc.reg, subc.CA} = (subcarry %b, %a)
    // (zext (setcc %a, %b, setgt)) ->
    //   (xor (adde (lshr %a, 63), (ashr %b, 63), subc.CA), 1)
    // (zext (setcc %a, 0, setgt)) -> (lshr (nor (add %a, -1), %a), 63)
    if (IsRHSNegOne)
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::GEZExt);
    if (IsRHSZero) {
      SDValue Addi =
        SDValue(CurDAG->getMachineNode(PPC::ADDI8, dl, MVT::i64, LHS,
                                       S->getI64Imm(~0ULL, dl)), 0);
      SDValue Nor =
        SDValue(CurDAG->getMachineNode(PPC::NOR8, dl, MVT::i64, Addi, LHS), 0);
      return SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, Nor,
                                            S->getI64Imm(1, dl),
                                            S->getI64Imm(63, dl)), 0);
    }
    std::swap(LHS, RHS);
    ConstantSDNode *RHSConst = dyn_cast<ConstantSDNode>(RHS);
    IsRHSZero = RHSConst && RHSConst->isZero();
    IsRHSOne = RHSConst && RHSConst->getSExtValue() == 1;
    [[fallthrough]];
  }
  case ISD::SETLT: {
    // {subc.reg, subc.CA} = (subcarry %a, %b)
    // (zext (setcc %a, %b, setlt)) ->
    //   (xor (adde (lshr %b, 63), (ashr %a, 63), subc.CA), 1)
    // (zext (setcc %a, 0, setlt)) -> (lshr %a, 63)
    if (IsRHSOne)
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::LEZExt);
    if (IsRHSZero)
      return SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, LHS,
                                            S->getI64Imm(1, dl),
                                            S->getI64Imm(63, dl)), 0);
    SDValue SRADINode =
      SDValue(CurDAG->getMachineNode(PPC::SRADI, dl, MVT::i64,
                                     LHS, S->getI64Imm(63, dl)), 0);
    SDValue SRDINode =
      SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64,
                                     RHS, S->getI64Imm(1, dl),
                                     S->getI64Imm(63, dl)), 0);
    SDValue SUBFC8Carry =
      SDValue(CurDAG->getMachineNode(PPC::SUBFC8, dl, MVT::i64, MVT::Glue,
                                     RHS, LHS), 1);
    SDValue ADDE8Node =
      SDValue(CurDAG->getMachineNode(PPC::ADDE8, dl, MVT::i64, MVT::Glue,
                                     SRDINode, SRADINode, SUBFC8Carry), 0);
    return SDValue(CurDAG->getMachineNode(PPC::XORI8, dl, MVT::i64,
                                          ADDE8Node, S->getI64Imm(1, dl)), 0);
  }
  case ISD::SETUGE:
    // {subc.reg, subc.CA} = (subcarry %a, %b)
    // (zext (setcc %a, %b, setuge)) -> (add (sube %b, %b, subc.CA), 1)
    std::swap(LHS, RHS);
    [[fallthrough]];
  case ISD::SETULE: {
    // {subc.reg, subc.CA} = (subcarry %b, %a)
    // (zext (setcc %a, %b, setule)) -> (add (sube %a, %a, subc.CA), 1)
    SDValue SUBFC8Carry =
      SDValue(CurDAG->getMachineNode(PPC::SUBFC8, dl, MVT::i64, MVT::Glue,
                                     LHS, RHS), 1);
    SDValue SUBFE8Node =
      SDValue(CurDAG->getMachineNode(PPC::SUBFE8, dl, MVT::i64, MVT::Glue,
                                     LHS, LHS, SUBFC8Carry), 0);
    return SDValue(CurDAG->getMachineNode(PPC::ADDI8, dl, MVT::i64,
                                          SUBFE8Node, S->getI64Imm(1, dl)), 0);
  }
  case ISD::SETUGT:
    // {subc.reg, subc.CA} = (subcarry %b, %a)
    // (zext (setcc %a, %b, setugt)) -> -(sube %b, %b, subc.CA)
    std::swap(LHS, RHS);
    [[fallthrough]];
  case ISD::SETULT: {
    // {subc.reg, subc.CA} = (subcarry %a, %b)
    // (zext (setcc %a, %b, setult)) -> -(sube %a, %a, subc.CA)
    SDValue SubtractCarry =
      SDValue(CurDAG->getMachineNode(PPC::SUBFC8, dl, MVT::i64, MVT::Glue,
                                     RHS, LHS), 1);
    SDValue ExtSub =
      SDValue(CurDAG->getMachineNode(PPC::SUBFE8, dl, MVT::i64,
                                     LHS, LHS, SubtractCarry), 0);
    return SDValue(CurDAG->getMachineNode(PPC::NEG8, dl, MVT::i64,
                                          ExtSub), 0);
  }
  }
}
 
/// Produces a sign-extended result of comparing two 64-bit values according to
/// the passed condition code.
SDValue
IntegerCompareEliminator::get64BitSExtCompare(SDValue LHS, SDValue RHS,
                                              ISD::CondCode CC,
                                              int64_t RHSValue, SDLoc dl) {
  if (CmpInGPR == ICGPR_I32 || CmpInGPR == ICGPR_SextI32 ||
      CmpInGPR == ICGPR_ZextI32 || CmpInGPR == ICGPR_Zext)
    return SDValue();
  bool IsRHSZero = RHSValue == 0;
  bool IsRHSOne = RHSValue == 1;
  bool IsRHSNegOne = RHSValue == -1LL;
  switch (CC) {
  default: return SDValue();
  case ISD::SETEQ: {
    // {addc.reg, addc.CA} = (addcarry (xor %a, %b), -1)
    // (sext (setcc %a, %b, seteq)) -> (sube addc.reg, addc.reg, addc.CA)
    // {addcz.reg, addcz.CA} = (addcarry %a, -1)
    // (sext (setcc %a, 0, seteq)) -> (sube addcz.reg, addcz.reg, addcz.CA)
    SDValue AddInput = IsRHSZero ? LHS :
      SDValue(CurDAG->getMachineNode(PPC::XOR8, dl, MVT::i64, LHS, RHS), 0);
    SDValue Addic =
      SDValue(CurDAG->getMachineNode(PPC::ADDIC8, dl, MVT::i64, MVT::Glue,
                                     AddInput, S->getI32Imm(~0U, dl)), 0);
    return SDValue(CurDAG->getMachineNode(PPC::SUBFE8, dl, MVT::i64, Addic,
                                          Addic, Addic.getValue(1)), 0);
  }
  case ISD::SETNE: {
    // {subfc.reg, subfc.CA} = (subcarry 0, (xor %a, %b))
    // (sext (setcc %a, %b, setne)) -> (sube subfc.reg, subfc.reg, subfc.CA)
    // {subfcz.reg, subfcz.CA} = (subcarry 0, %a)
    // (sext (setcc %a, 0, setne)) -> (sube subfcz.reg, subfcz.reg, subfcz.CA)
    SDValue Xor = IsRHSZero ? LHS :
      SDValue(CurDAG->getMachineNode(PPC::XOR8, dl, MVT::i64, LHS, RHS), 0);
    SDValue SC =
      SDValue(CurDAG->getMachineNode(PPC::SUBFIC8, dl, MVT::i64, MVT::Glue,
                                     Xor, S->getI32Imm(0, dl)), 0);
    return SDValue(CurDAG->getMachineNode(PPC::SUBFE8, dl, MVT::i64, SC,
                                          SC, SC.getValue(1)), 0);
  }
  case ISD::SETGE: {
    // {subc.reg, subc.CA} = (subcarry %a, %b)
    // (zext (setcc %a, %b, setge)) ->
    //   (- (adde (lshr %b, 63), (ashr %a, 63), subc.CA))
    // (zext (setcc %a, 0, setge)) -> (~ (ashr %a, 63))
    if (IsRHSZero)
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::GESExt);
    std::swap(LHS, RHS);
    ConstantSDNode *RHSConst = dyn_cast<ConstantSDNode>(RHS);
    IsRHSZero = RHSConst && RHSConst->isZero();
    [[fallthrough]];
  }
  case ISD::SETLE: {
    // {subc.reg, subc.CA} = (subcarry %b, %a)
    // (zext (setcc %a, %b, setge)) ->
    //   (- (adde (lshr %a, 63), (ashr %b, 63), subc.CA))
    // (zext (setcc %a, 0, setge)) -> (ashr (or %a, (add %a, -1)), 63)
    if (IsRHSZero)
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::LESExt);
    SDValue ShiftR =
      SDValue(CurDAG->getMachineNode(PPC::SRADI, dl, MVT::i64, RHS,
                                     S->getI64Imm(63, dl)), 0);
    SDValue ShiftL =
      SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, LHS,
                                     S->getI64Imm(1, dl),
                                     S->getI64Imm(63, dl)), 0);
    SDValue SubtractCarry =
      SDValue(CurDAG->getMachineNode(PPC::SUBFC8, dl, MVT::i64, MVT::Glue,
                                     LHS, RHS), 1);
    SDValue Adde =
      SDValue(CurDAG->getMachineNode(PPC::ADDE8, dl, MVT::i64, MVT::Glue,
                                     ShiftR, ShiftL, SubtractCarry), 0);
    return SDValue(CurDAG->getMachineNode(PPC::NEG8, dl, MVT::i64, Adde), 0);
  }
  case ISD::SETGT: {
    // {subc.reg, subc.CA} = (subcarry %b, %a)
    // (zext (setcc %a, %b, setgt)) ->
    //   -(xor (adde (lshr %a, 63), (ashr %b, 63), subc.CA), 1)
    // (zext (setcc %a, 0, setgt)) -> (ashr (nor (add %a, -1), %a), 63)
    if (IsRHSNegOne)
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::GESExt);
    if (IsRHSZero) {
      SDValue Add =
        SDValue(CurDAG->getMachineNode(PPC::ADDI8, dl, MVT::i64, LHS,
                                       S->getI64Imm(-1, dl)), 0);
      SDValue Nor =
        SDValue(CurDAG->getMachineNode(PPC::NOR8, dl, MVT::i64, Add, LHS), 0);
      return SDValue(CurDAG->getMachineNode(PPC::SRADI, dl, MVT::i64, Nor,
                                            S->getI64Imm(63, dl)), 0);
    }
    std::swap(LHS, RHS);
    ConstantSDNode *RHSConst = dyn_cast<ConstantSDNode>(RHS);
    IsRHSZero = RHSConst && RHSConst->isZero();
    IsRHSOne = RHSConst && RHSConst->getSExtValue() == 1;
    [[fallthrough]];
  }
  case ISD::SETLT: {
    // {subc.reg, subc.CA} = (subcarry %a, %b)
    // (zext (setcc %a, %b, setlt)) ->
    //   -(xor (adde (lshr %b, 63), (ashr %a, 63), subc.CA), 1)
    // (zext (setcc %a, 0, setlt)) -> (ashr %a, 63)
    if (IsRHSOne)
      return getCompoundZeroComparisonInGPR(LHS, dl, ZeroCompare::LESExt);
    if (IsRHSZero) {
      return SDValue(CurDAG->getMachineNode(PPC::SRADI, dl, MVT::i64, LHS,
                                            S->getI64Imm(63, dl)), 0);
    }
    SDValue SRADINode =
      SDValue(CurDAG->getMachineNode(PPC::SRADI, dl, MVT::i64,
                                     LHS, S->getI64Imm(63, dl)), 0);
    SDValue SRDINode =
      SDValue(CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64,
                                     RHS, S->getI64Imm(1, dl),
                                     S->getI64Imm(63, dl)), 0);
    SDValue SUBFC8Carry =
      SDValue(CurDAG->getMachineNode(PPC::SUBFC8, dl, MVT::i64, MVT::Glue,
                                     RHS, LHS), 1);
    SDValue ADDE8Node =
      SDValue(CurDAG->getMachineNode(PPC::ADDE8, dl, MVT::i64,
                                     SRDINode, SRADINode, SUBFC8Carry), 0);
    SDValue XORI8Node =
      SDValue(CurDAG->getMachineNode(PPC::XORI8, dl, MVT::i64,
                                     ADDE8Node, S->getI64Imm(1, dl)), 0);
    return SDValue(CurDAG->getMachineNode(PPC::NEG8, dl, MVT::i64,
                                          XORI8Node), 0);
  }
  case ISD::SETUGE:
    // {subc.reg, subc.CA} = (subcarry %a, %b)
    // (sext (setcc %a, %b, setuge)) -> ~(sube %b, %b, subc.CA)
    std::swap(LHS, RHS);
    [[fallthrough]];
  case ISD::SETULE: {
    // {subc.reg, subc.CA} = (subcarry %b, %a)
    // (sext (setcc %a, %b, setule)) -> ~(sube %a, %a, subc.CA)
    SDValue SubtractCarry =
      SDValue(CurDAG->getMachineNode(PPC::SUBFC8, dl, MVT::i64, MVT::Glue,
                                     LHS, RHS), 1);
    SDValue ExtSub =
      SDValue(CurDAG->getMachineNode(PPC::SUBFE8, dl, MVT::i64, MVT::Glue, LHS,
                                     LHS, SubtractCarry), 0);
    return SDValue(CurDAG->getMachineNode(PPC::NOR8, dl, MVT::i64,
                                          ExtSub, ExtSub), 0);
  }
  case ISD::SETUGT:
    // {subc.reg, subc.CA} = (subcarry %b, %a)
    // (sext (setcc %a, %b, setugt)) -> (sube %b, %b, subc.CA)
    std::swap(LHS, RHS);
    [[fallthrough]];
  case ISD::SETULT: {
    // {subc.reg, subc.CA} = (subcarry %a, %b)
    // (sext (setcc %a, %b, setult)) -> (sube %a, %a, subc.CA)
    SDValue SubCarry =
      SDValue(CurDAG->getMachineNode(PPC::SUBFC8, dl, MVT::i64, MVT::Glue,
                                     RHS, LHS), 1);
    return SDValue(CurDAG->getMachineNode(PPC::SUBFE8, dl, MVT::i64,
                                     LHS, LHS, SubCarry), 0);
  }
  }
}
 
/// Do all uses of this SDValue need the result in a GPR?
/// This is meant to be used on values that have type i1 since
/// it is somewhat meaningless to ask if values of other types
/// should be kept in GPR's.
static bool allUsesExtend(SDValue Compare, SelectionDAG *CurDAG) {
  assert(Compare.getOpcode() == ISD::SETCC &&
         "An ISD::SETCC node required here.");
 
  // For values that have a single use, the caller should obviously already have
  // checked if that use is an extending use. We check the other uses here.
  if (Compare.hasOneUse())
    return true;
  // We want the value in a GPR if it is being extended, used for a select, or
  // used in logical operations.
  for (auto *CompareUse : Compare.getNode()->uses())
    if (CompareUse->getOpcode() != ISD::SIGN_EXTEND &&
        CompareUse->getOpcode() != ISD::ZERO_EXTEND &&
        CompareUse->getOpcode() != ISD::SELECT &&
        !isLogicOp(CompareUse->getOpcode())) {
      OmittedForNonExtendUses++;
      return false;
    }
  return true;
}
 
/// Returns an equivalent of a SETCC node but with the result the same width as
/// the inputs. This can also be used for SELECT_CC if either the true or false
/// values is a power of two while the other is zero.
SDValue IntegerCompareEliminator::getSETCCInGPR(SDValue Compare,
                                                SetccInGPROpts ConvOpts) {
  assert((Compare.getOpcode() == ISD::SETCC ||
          Compare.getOpcode() == ISD::SELECT_CC) &&
         "An ISD::SETCC node required here.");
 
  // Don't convert this comparison to a GPR sequence because there are uses
  // of the i1 result (i.e. uses that require the result in the CR).
  if ((Compare.getOpcode() == ISD::SETCC) && !allUsesExtend(Compare, CurDAG))
    return SDValue();
 
  SDValue LHS = Compare.getOperand(0);
  SDValue RHS = Compare.getOperand(1);
 
  // The condition code is operand 2 for SETCC and operand 4 for SELECT_CC.
  int CCOpNum = Compare.getOpcode() == ISD::SELECT_CC ? 4 : 2;
  ISD::CondCode CC =
    cast<CondCodeSDNode>(Compare.getOperand(CCOpNum))->get();
  EVT InputVT = LHS.getValueType();
  if (InputVT != MVT::i32 && InputVT != MVT::i64)
    return SDValue();
 
  if (ConvOpts == SetccInGPROpts::ZExtInvert ||
      ConvOpts == SetccInGPROpts::SExtInvert)
    CC = ISD::getSetCCInverse(CC, InputVT);
 
  bool Inputs32Bit = InputVT == MVT::i32;
 
  SDLoc dl(Compare);
  ConstantSDNode *RHSConst = dyn_cast<ConstantSDNode>(RHS);
  int64_t RHSValue = RHSConst ? RHSConst->getSExtValue() : INT64_MAX;
  bool IsSext = ConvOpts == SetccInGPROpts::SExtOrig ||
    ConvOpts == SetccInGPROpts::SExtInvert;
 
  if (IsSext && Inputs32Bit)
    return get32BitSExtCompare(LHS, RHS, CC, RHSValue, dl);
  else if (Inputs32Bit)
    return get32BitZExtCompare(LHS, RHS, CC, RHSValue, dl);
  else if (IsSext)
    return get64BitSExtCompare(LHS, RHS, CC, RHSValue, dl);
  return get64BitZExtCompare(LHS, RHS, CC, RHSValue, dl);
}
 
} // end anonymous namespace
 
bool PPCDAGToDAGISel::tryIntCompareInGPR(SDNode *N) {
  if (N->getValueType(0) != MVT::i32 &&
      N->getValueType(0) != MVT::i64)
    return false;
 
  // This optimization will emit code that assumes 64-bit registers
  // so we don't want to run it in 32-bit mode. Also don't run it
  // on functions that are not to be optimized.
  if (TM.getOptLevel() == CodeGenOpt::None || !TM.isPPC64())
    return false;
 
  // For POWER10, it is more profitable to use the set boolean extension
  // instructions rather than the integer compare elimination codegen.
  // Users can override this via the command line option, `--ppc-gpr-icmps`.
  if (!(CmpInGPR.getNumOccurrences() > 0) && Subtarget->isISA3_1())
    return false;
 
  switch (N->getOpcode()) {
  default: break;
  case ISD::ZERO_EXTEND:
  case ISD::SIGN_EXTEND:
  case ISD::AND:
  case ISD::OR:
  case ISD::XOR: {
    IntegerCompareEliminator ICmpElim(CurDAG, this);
    if (SDNode *New = ICmpElim.Select(N)) {
      ReplaceNode(N, New);
      return true;
    }
  }
  }
  return false;
}
 
bool PPCDAGToDAGISel::tryBitPermutation(SDNode *N) {
  if (N->getValueType(0) != MVT::i32 &&
      N->getValueType(0) != MVT::i64)
    return false;
 
  if (!UseBitPermRewriter)
    return false;
 
  switch (N->getOpcode()) {
  default: break;
  case ISD::ROTL:
  case ISD::SHL:
  case ISD::SRL:
  case ISD::AND:
  case ISD::OR: {
    BitPermutationSelector BPS(CurDAG);
    if (SDNode *New = BPS.Select(N)) {
      ReplaceNode(N, New);
      return true;
    }
    return false;
  }
  }
 
  return false;
}
 
/// SelectCC - Select a comparison of the specified values with the specified
/// condition code, returning the CR# of the expression.
SDValue PPCDAGToDAGISel::SelectCC(SDValue LHS, SDValue RHS, ISD::CondCode CC,
                                  const SDLoc &dl, SDValue Chain) {
  // Always select the LHS.
  unsigned Opc;
 
  if (LHS.getValueType() == MVT::i32) {
    unsigned Imm;
    if (CC == ISD::SETEQ || CC == ISD::SETNE) {
      if (isInt32Immediate(RHS, Imm)) {
        // SETEQ/SETNE comparison with 16-bit immediate, fold it.
        if (isUInt<16>(Imm))
          return SDValue(CurDAG->getMachineNode(PPC::CMPLWI, dl, MVT::i32, LHS,
                                                getI32Imm(Imm & 0xFFFF, dl)),
                         0);
        // If this is a 16-bit signed immediate, fold it.
        if (isInt<16>((int)Imm))
          return SDValue(CurDAG->getMachineNode(PPC::CMPWI, dl, MVT::i32, LHS,
                                                getI32Imm(Imm & 0xFFFF, dl)),
                         0);
 
        // For non-equality comparisons, the default code would materialize the
        // constant, then compare against it, like this:
        //   lis r2, 4660
        //   ori r2, r2, 22136
        //   cmpw cr0, r3, r2
        // Since we are just comparing for equality, we can emit this instead:
        //   xoris r0,r3,0x1234
        //   cmplwi cr0,r0,0x5678
        //   beq cr0,L6
        SDValue Xor(CurDAG->getMachineNode(PPC::XORIS, dl, MVT::i32, LHS,
                                           getI32Imm(Imm >> 16, dl)), 0);
        return SDValue(CurDAG->getMachineNode(PPC::CMPLWI, dl, MVT::i32, Xor,
                                              getI32Imm(Imm & 0xFFFF, dl)), 0);
      }
      Opc = PPC::CMPLW;
    } else if (ISD::isUnsignedIntSetCC(CC)) {
      if (isInt32Immediate(RHS, Imm) && isUInt<16>(Imm))
        return SDValue(CurDAG->getMachineNode(PPC::CMPLWI, dl, MVT::i32, LHS,
                                              getI32Imm(Imm & 0xFFFF, dl)), 0);
      Opc = PPC::CMPLW;
    } else {
      int16_t SImm;
      if (isIntS16Immediate(RHS, SImm))
        return SDValue(CurDAG->getMachineNode(PPC::CMPWI, dl, MVT::i32, LHS,
                                              getI32Imm((int)SImm & 0xFFFF,
                                                        dl)),
                         0);
      Opc = PPC::CMPW;
    }
  } else if (LHS.getValueType() == MVT::i64) {
    uint64_t Imm;
    if (CC == ISD::SETEQ || CC == ISD::SETNE) {
      if (isInt64Immediate(RHS.getNode(), Imm)) {
        // SETEQ/SETNE comparison with 16-bit immediate, fold it.
        if (isUInt<16>(Imm))
          return SDValue(CurDAG->getMachineNode(PPC::CMPLDI, dl, MVT::i64, LHS,
                                                getI32Imm(Imm & 0xFFFF, dl)),
                         0);
        // If this is a 16-bit signed immediate, fold it.
        if (isInt<16>(Imm))
          return SDValue(CurDAG->getMachineNode(PPC::CMPDI, dl, MVT::i64, LHS,
                                                getI32Imm(Imm & 0xFFFF, dl)),
                         0);
 
        // For non-equality comparisons, the default code would materialize the
        // constant, then compare against it, like this:
        //   lis r2, 4660
        //   ori r2, r2, 22136
        //   cmpd cr0, r3, r2
        // Since we are just comparing for equality, we can emit this instead:
        //   xoris r0,r3,0x1234
        //   cmpldi cr0,r0,0x5678
        //   beq cr0,L6
        if (isUInt<32>(Imm)) {
          SDValue Xor(CurDAG->getMachineNode(PPC::XORIS8, dl, MVT::i64, LHS,
                                             getI64Imm(Imm >> 16, dl)), 0);
          return SDValue(CurDAG->getMachineNode(PPC::CMPLDI, dl, MVT::i64, Xor,
                                                getI64Imm(Imm & 0xFFFF, dl)),
                         0);
        }
      }
      Opc = PPC::CMPLD;
    } else if (ISD::isUnsignedIntSetCC(CC)) {
      if (isInt64Immediate(RHS.getNode(), Imm) && isUInt<16>(Imm))
        return SDValue(CurDAG->getMachineNode(PPC::CMPLDI, dl, MVT::i64, LHS,
                                              getI64Imm(Imm & 0xFFFF, dl)), 0);
      Opc = PPC::CMPLD;
    } else {
      int16_t SImm;
      if (isIntS16Immediate(RHS, SImm))
        return SDValue(CurDAG->getMachineNode(PPC::CMPDI, dl, MVT::i64, LHS,
                                              getI64Imm(SImm & 0xFFFF, dl)),
                         0);
      Opc = PPC::CMPD;
    }
  } else if (LHS.getValueType() == MVT::f32) {
    if (Subtarget->hasSPE()) {
      switch (CC) {
        default:
        case ISD::SETEQ:
        case ISD::SETNE:
          Opc = PPC::EFSCMPEQ;
          break;
        case ISD::SETLT:
        case ISD::SETGE:
        case ISD::SETOLT:
        case ISD::SETOGE:
        case ISD::SETULT:
        case ISD::SETUGE:
          Opc = PPC::EFSCMPLT;
          break;
        case ISD::SETGT:
        case ISD::SETLE:
        case ISD::SETOGT:
        case ISD::SETOLE:
        case ISD::SETUGT:
        case ISD::SETULE:
          Opc = PPC::EFSCMPGT;
          break;
      }
    } else
      Opc = PPC::FCMPUS;
  } else if (LHS.getValueType() == MVT::f64) {
    if (Subtarget->hasSPE()) {
      switch (CC) {
        default:
        case ISD::SETEQ:
        case ISD::SETNE:
          Opc = PPC::EFDCMPEQ;
          break;
        case ISD::SETLT:
        case ISD::SETGE:
        case ISD::SETOLT:
        case ISD::SETOGE:
        case ISD::SETULT:
        case ISD::SETUGE:
          Opc = PPC::EFDCMPLT;
          break;
        case ISD::SETGT:
        case ISD::SETLE:
        case ISD::SETOGT:
        case ISD::SETOLE:
        case ISD::SETUGT:
        case ISD::SETULE:
          Opc = PPC::EFDCMPGT;
          break;
      }
    } else
      Opc = Subtarget->hasVSX() ? PPC::XSCMPUDP : PPC::FCMPUD;
  } else {
    assert(LHS.getValueType() == MVT::f128 && "Unknown vt!");
    assert(Subtarget->hasP9Vector() && "XSCMPUQP requires Power9 Vector");
    Opc = PPC::XSCMPUQP;
  }
  if (Chain)
    return SDValue(
        CurDAG->getMachineNode(Opc, dl, MVT::i32, MVT::Other, LHS, RHS, Chain),
        0);
  else
    return SDValue(CurDAG->getMachineNode(Opc, dl, MVT::i32, LHS, RHS), 0);
}
 
static PPC::Predicate getPredicateForSetCC(ISD::CondCode CC, const EVT &VT,
                                           const PPCSubtarget *Subtarget) {
  // For SPE instructions, the result is in GT bit of the CR
  bool UseSPE = Subtarget->hasSPE() && VT.isFloatingPoint();
 
  switch (CC) {
  case ISD::SETUEQ:
  case ISD::SETONE:
  case ISD::SETOLE:
  case ISD::SETOGE:
    llvm_unreachable("Should be lowered by legalize!");
  default: llvm_unreachable("Unknown condition!");
  case ISD::SETOEQ:
  case ISD::SETEQ:
    return UseSPE ? PPC::PRED_GT : PPC::PRED_EQ;
  case ISD::SETUNE:
  case ISD::SETNE:
    return UseSPE ? PPC::PRED_LE : PPC::PRED_NE;
  case ISD::SETOLT:
  case ISD::SETLT:
    return UseSPE ? PPC::PRED_GT : PPC::PRED_LT;
  case ISD::SETULE:
  case ISD::SETLE:
    return PPC::PRED_LE;
  case ISD::SETOGT:
  case ISD::SETGT:
    return PPC::PRED_GT;
  case ISD::SETUGE:
  case ISD::SETGE:
    return UseSPE ? PPC::PRED_LE : PPC::PRED_GE;
  case ISD::SETO:   return PPC::PRED_NU;
  case ISD::SETUO:  return PPC::PRED_UN;
    // These two are invalid for floating point.  Assume we have int.
  case ISD::SETULT: return PPC::PRED_LT;
  case ISD::SETUGT: return PPC::PRED_GT;
  }
}
 
/// getCRIdxForSetCC - Return the index of the condition register field
/// associated with the SetCC condition, and whether or not the field is
/// treated as inverted.  That is, lt = 0; ge = 0 inverted.
static unsigned getCRIdxForSetCC(ISD::CondCode CC, bool &Invert) {
  Invert = false;
  switch (CC) {
  default: llvm_unreachable("Unknown condition!");
  case ISD::SETOLT:
  case ISD::SETLT:  return 0;                  // Bit #0 = SETOLT
  case ISD::SETOGT:
  case ISD::SETGT:  return 1;                  // Bit #1 = SETOGT
  case ISD::SETOEQ:
  case ISD::SETEQ:  return 2;                  // Bit #2 = SETOEQ
  case ISD::SETUO:  return 3;                  // Bit #3 = SETUO
  case ISD::SETUGE:
  case ISD::SETGE:  Invert = true; return 0;   // !Bit #0 = SETUGE
  case ISD::SETULE:
  case ISD::SETLE:  Invert = true; return 1;   // !Bit #1 = SETULE
  case ISD::SETUNE:
  case ISD::SETNE:  Invert = true; return 2;   // !Bit #2 = SETUNE
  case ISD::SETO:   Invert = true; return 3;   // !Bit #3 = SETO
  case ISD::SETUEQ:
  case ISD::SETOGE:
  case ISD::SETOLE:
  case ISD::SETONE:
    llvm_unreachable("Invalid branch code: should be expanded by legalize");
  // These are invalid for floating point.  Assume integer.
  case ISD::SETULT: return 0;
  case ISD::SETUGT: return 1;
  }
}
 
// getVCmpInst: return the vector compare instruction for the specified
// vector type and condition code. Since this is for altivec specific code,
// only support the altivec types (v16i8, v8i16, v4i32, v2i64, v1i128,
// and v4f32).
static unsigned int getVCmpInst(MVT VecVT, ISD::CondCode CC,
                                bool HasVSX, bool &Swap, bool &Negate) {
  Swap = false;
  Negate = false;
 
  if (VecVT.isFloatingPoint()) {
    /* Handle some cases by swapping input operands.  */
    switch (CC) {
      case ISD::SETLE: CC = ISD::SETGE; Swap = true; break;
      case ISD::SETLT: CC = ISD::SETGT; Swap = true; break;
      case ISD::SETOLE: CC = ISD::SETOGE; Swap = true; break;
      case ISD::SETOLT: CC = ISD::SETOGT; Swap = true; break;
      case ISD::SETUGE: CC = ISD::SETULE; Swap = true; break;
      case ISD::SETUGT: CC = ISD::SETULT; Swap = true; break;
      default: break;
    }
    /* Handle some cases by negating the result.  */
    switch (CC) {
      case ISD::SETNE: CC = ISD::SETEQ; Negate = true; break;
      case ISD::SETUNE: CC = ISD::SETOEQ; Negate = true; break;
      case ISD::SETULE: CC = ISD::SETOGT; Negate = true; break;
      case ISD::SETULT: CC = ISD::SETOGE; Negate = true; break;
      default: break;
    }
    /* We have instructions implementing the remaining cases.  */
    switch (CC) {
      case ISD::SETEQ:
      case ISD::SETOEQ:
        if (VecVT == MVT::v4f32)
          return HasVSX ? PPC::XVCMPEQSP : PPC::VCMPEQFP;
        else if (VecVT == MVT::v2f64)
          return PPC::XVCMPEQDP;
        break;
      case ISD::SETGT:
      case ISD::SETOGT:
        if (VecVT == MVT::v4f32)
          return HasVSX ? PPC::XVCMPGTSP : PPC::VCMPGTFP;
        else if (VecVT == MVT::v2f64)
          return PPC::XVCMPGTDP;
        break;
      case ISD::SETGE:
      case ISD::SETOGE:
        if (VecVT == MVT::v4f32)
          return HasVSX ? PPC::XVCMPGESP : PPC::VCMPGEFP;
        else if (VecVT == MVT::v2f64)
          return PPC::XVCMPGEDP;
        break;
      default:
        break;
    }
    llvm_unreachable("Invalid floating-point vector compare condition");
  } else {
    /* Handle some cases by swapping input operands.  */
    switch (CC) {
      case ISD::SETGE: CC = ISD::SETLE; Swap = true; break;
      case ISD::SETLT: CC = ISD::SETGT; Swap = true; break;
      case ISD::SETUGE: CC = ISD::SETULE; Swap = true; break;
      case ISD::SETULT: CC = ISD::SETUGT; Swap = true; break;
      default: break;
    }
    /* Handle some cases by negating the result.  */
    switch (CC) {
      case ISD::SETNE: CC = ISD::SETEQ; Negate = true; break;
      case ISD::SETUNE: CC = ISD::SETUEQ; Negate = true; break;
      case ISD::SETLE: CC = ISD::SETGT; Negate = true; break;
      case ISD::SETULE: CC = ISD::SETUGT; Negate = true; break;
      default: break;
    }
    /* We have instructions implementing the remaining cases.  */
    switch (CC) {
      case ISD::SETEQ:
      case ISD::SETUEQ:
        if (VecVT == MVT::v16i8)
          return PPC::VCMPEQUB;
        else if (VecVT == MVT::v8i16)
          return PPC::VCMPEQUH;
        else if (VecVT == MVT::v4i32)
          return PPC::VCMPEQUW;
        else if (VecVT == MVT::v2i64)
          return PPC::VCMPEQUD;
        else if (VecVT == MVT::v1i128)
          return PPC::VCMPEQUQ;
        break;
      case ISD::SETGT:
        if (VecVT == MVT::v16i8)
          return PPC::VCMPGTSB;
        else if (VecVT == MVT::v8i16)
          return PPC::VCMPGTSH;
        else if (VecVT == MVT::v4i32)
          return PPC::VCMPGTSW;
        else if (VecVT == MVT::v2i64)
          return PPC::VCMPGTSD;
        else if (VecVT == MVT::v1i128)
           return PPC::VCMPGTSQ;
        break;
      case ISD::SETUGT:
        if (VecVT == MVT::v16i8)
          return PPC::VCMPGTUB;
        else if (VecVT == MVT::v8i16)
          return PPC::VCMPGTUH;
        else if (VecVT == MVT::v4i32)
          return PPC::VCMPGTUW;
        else if (VecVT == MVT::v2i64)
          return PPC::VCMPGTUD;
        else if (VecVT == MVT::v1i128)
           return PPC::VCMPGTUQ;
        break;
      default:
        break;
    }
    llvm_unreachable("Invalid integer vector compare condition");
  }
}
 
bool PPCDAGToDAGISel::trySETCC(SDNode *N) {
  SDLoc dl(N);
  unsigned Imm;
  bool IsStrict = N->isStrictFPOpcode();
  ISD::CondCode CC =
      cast<CondCodeSDNode>(N->getOperand(IsStrict ? 3 : 2))->get();
  EVT PtrVT =
      CurDAG->getTargetLoweringInfo().getPointerTy(CurDAG->getDataLayout());
  bool isPPC64 = (PtrVT == MVT::i64);
  SDValue Chain = IsStrict ? N->getOperand(0) : SDValue();
 
  SDValue LHS = N->getOperand(IsStrict ? 1 : 0);
  SDValue RHS = N->getOperand(IsStrict ? 2 : 1);
 
  if (!IsStrict && !Subtarget->useCRBits() && isInt32Immediate(RHS, Imm)) {
    // We can codegen setcc op, imm very efficiently compared to a brcond.
    // Check for those cases here.
    // setcc op, 0
    if (Imm == 0) {
      SDValue Op = LHS;
      switch (CC) {
      default: break;
      case ISD::SETEQ: {
        Op = SDValue(CurDAG->getMachineNode(PPC::CNTLZW, dl, MVT::i32, Op), 0);
        SDValue Ops[] = { Op, getI32Imm(27, dl), getI32Imm(5, dl),
                          getI32Imm(31, dl) };
        CurDAG->SelectNodeTo(N, PPC::RLWINM, MVT::i32, Ops);
        return true;
      }
      case ISD::SETNE: {
        if (isPPC64) break;
        SDValue AD =
          SDValue(CurDAG->getMachineNode(PPC::ADDIC, dl, MVT::i32, MVT::Glue,
                                         Op, getI32Imm(~0U, dl)), 0);
        CurDAG->SelectNodeTo(N, PPC::SUBFE, MVT::i32, AD, Op, AD.getValue(1));
        return true;
      }
      case ISD::SETLT: {
        SDValue Ops[] = { Op, getI32Imm(1, dl), getI32Imm(31, dl),
                          getI32Imm(31, dl) };
        CurDAG->SelectNodeTo(N, PPC::RLWINM, MVT::i32, Ops);
        return true;
      }
      case ISD::SETGT: {
        SDValue T =
          SDValue(CurDAG->getMachineNode(PPC::NEG, dl, MVT::i32, Op), 0);
        T = SDValue(CurDAG->getMachineNode(PPC::ANDC, dl, MVT::i32, T, Op), 0);
        SDValue Ops[] = { T, getI32Imm(1, dl), getI32Imm(31, dl),
                          getI32Imm(31, dl) };
        CurDAG->SelectNodeTo(N, PPC::RLWINM, MVT::i32, Ops);
        return true;
      }
      }
    } else if (Imm == ~0U) {        // setcc op, -1
      SDValue Op = LHS;
      switch (CC) {
      default: break;
      case ISD::SETEQ:
        if (isPPC64) break;
        Op = SDValue(CurDAG->getMachineNode(PPC::ADDIC, dl, MVT::i32, MVT::Glue,
                                            Op, getI32Imm(1, dl)), 0);
        CurDAG->SelectNodeTo(N, PPC::ADDZE, MVT::i32,
                             SDValue(CurDAG->getMachineNode(PPC::LI, dl,
                                                            MVT::i32,
                                                            getI32Imm(0, dl)),
                                     0), Op.getValue(1));
        return true;
      case ISD::SETNE: {
        if (isPPC64) break;
        Op = SDValue(CurDAG->getMachineNode(PPC::NOR, dl, MVT::i32, Op, Op), 0);
        SDNode *AD = CurDAG->getMachineNode(PPC::ADDIC, dl, MVT::i32, MVT::Glue,
                                            Op, getI32Imm(~0U, dl));
        CurDAG->SelectNodeTo(N, PPC::SUBFE, MVT::i32, SDValue(AD, 0), Op,
                             SDValue(AD, 1));
        return true;
      }
      case ISD::SETLT: {
        SDValue AD = SDValue(CurDAG->getMachineNode(PPC::ADDI, dl, MVT::i32, Op,
                                                    getI32Imm(1, dl)), 0);
        SDValue AN = SDValue(CurDAG->getMachineNode(PPC::AND, dl, MVT::i32, AD,
                                                    Op), 0);
        SDValue Ops[] = { AN, getI32Imm(1, dl), getI32Imm(31, dl),
                          getI32Imm(31, dl) };
        CurDAG->SelectNodeTo(N, PPC::RLWINM, MVT::i32, Ops);
        return true;
      }
      case ISD::SETGT: {
        SDValue Ops[] = { Op, getI32Imm(1, dl), getI32Imm(31, dl),
                          getI32Imm(31, dl) };
        Op = SDValue(CurDAG->getMachineNode(PPC::RLWINM, dl, MVT::i32, Ops), 0);
        CurDAG->SelectNodeTo(N, PPC::XORI, MVT::i32, Op, getI32Imm(1, dl));
        return true;
      }
      }
    }
  }
 
  // Altivec Vector compare instructions do not set any CR register by default and
  // vector compare operations return the same type as the operands.
  if (!IsStrict && LHS.getValueType().isVector()) {
    if (Subtarget->hasSPE())
      return false;
 
    EVT VecVT = LHS.getValueType();
    bool Swap, Negate;
    unsigned int VCmpInst =
        getVCmpInst(VecVT.getSimpleVT(), CC, Subtarget->hasVSX(), Swap, Negate);
    if (Swap)
      std::swap(LHS, RHS);
 
    EVT ResVT = VecVT.changeVectorElementTypeToInteger();
    if (Negate) {
      SDValue VCmp(CurDAG->getMachineNode(VCmpInst, dl, ResVT, LHS, RHS), 0);
      CurDAG->SelectNodeTo(N, Subtarget->hasVSX() ? PPC::XXLNOR : PPC::VNOR,
                           ResVT, VCmp, VCmp);
      return true;
    }
 
    CurDAG->SelectNodeTo(N, VCmpInst, ResVT, LHS, RHS);
    return true;
  }
 
  if (Subtarget->useCRBits())
    return false;
 
  bool Inv;
  unsigned Idx = getCRIdxForSetCC(CC, Inv);
  SDValue CCReg = SelectCC(LHS, RHS, CC, dl, Chain);
  if (IsStrict)
    CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 1), CCReg.getValue(1));
  SDValue IntCR;
 
  // SPE e*cmp* instructions only set the 'gt' bit, so hard-code that
  // The correct compare instruction is already set by SelectCC()
  if (Subtarget->hasSPE() && LHS.getValueType().isFloatingPoint()) {
    Idx = 1;
  }
 
  // Force the ccreg into CR7.
  SDValue CR7Reg = CurDAG->getRegister(PPC::CR7, MVT::i32);
 
  SDValue InFlag;  // Null incoming flag value.
  CCReg = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, CR7Reg, CCReg,
                               InFlag).getValue(1);
 
  IntCR = SDValue(CurDAG->getMachineNode(PPC::MFOCRF, dl, MVT::i32, CR7Reg,
                                         CCReg), 0);
 
  SDValue Ops[] = { IntCR, getI32Imm((32 - (3 - Idx)) & 31, dl),
                      getI32Imm(31, dl), getI32Imm(31, dl) };
  if (!Inv) {
    CurDAG->SelectNodeTo(N, PPC::RLWINM, MVT::i32, Ops);
    return true;
  }
 
  // Get the specified bit.
  SDValue Tmp =
    SDValue(CurDAG->getMachineNode(PPC::RLWINM, dl, MVT::i32, Ops), 0);
  CurDAG->SelectNodeTo(N, PPC::XORI, MVT::i32, Tmp, getI32Imm(1, dl));
  return true;
}
 
/// Does this node represent a load/store node whose address can be represented
/// with a register plus an immediate that's a multiple of \p Val:
bool PPCDAGToDAGISel::isOffsetMultipleOf(SDNode *N, unsigned Val) const {
  LoadSDNode *LDN = dyn_cast<LoadSDNode>(N);
  StoreSDNode *STN = dyn_cast<StoreSDNode>(N);
  MemIntrinsicSDNode *MIN = dyn_cast<MemIntrinsicSDNode>(N);
  SDValue AddrOp;
  if (LDN || (MIN && MIN->getOpcode() == PPCISD::LD_SPLAT))
    AddrOp = N->getOperand(1);
  else if (STN)
    AddrOp = STN->getOperand(2);
 
  // If the address points a frame object or a frame object with an offset,
  // we need to check the object alignment.
  short Imm = 0;
  if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(
          AddrOp.getOpcode() == ISD::ADD ? AddrOp.getOperand(0) :
                                           AddrOp)) {
    // If op0 is a frame index that is under aligned, we can't do it either,
    // because it is translated to r31 or r1 + slot + offset. We won't know the
    // slot number until the stack frame is finalized.
    const MachineFrameInfo &MFI = CurDAG->getMachineFunction().getFrameInfo();
    unsigned SlotAlign = MFI.getObjectAlign(FI->getIndex()).value();
    if ((SlotAlign % Val) != 0)
      return false;
 
    // If we have an offset, we need further check on the offset.
    if (AddrOp.getOpcode() != ISD::ADD)
      return true;
  }
 
  if (AddrOp.getOpcode() == ISD::ADD)
    return isIntS16Immediate(AddrOp.getOperand(1), Imm) && !(Imm % Val);
 
  // If the address comes from the outside, the offset will be zero.
  return AddrOp.getOpcode() == ISD::CopyFromReg;
}
 
void PPCDAGToDAGISel::transferMemOperands(SDNode *N, SDNode *Result) {
  // Transfer memoperands.
  MachineMemOperand *MemOp = cast<MemSDNode>(N)->getMemOperand();
  CurDAG->setNodeMemRefs(cast<MachineSDNode>(Result), {MemOp});
}
 
static bool mayUseP9Setb(SDNode *N, const ISD::CondCode &CC, SelectionDAG *DAG,
                         bool &NeedSwapOps, bool &IsUnCmp) {
 
  assert(N->getOpcode() == ISD::SELECT_CC && "Expecting a SELECT_CC here.");
 
  SDValue LHS = N->getOperand(0);
  SDValue RHS = N->getOperand(1);
  SDValue TrueRes = N->getOperand(2);
  SDValue FalseRes = N->getOperand(3);
  ConstantSDNode *TrueConst = dyn_cast<ConstantSDNode>(TrueRes);
  if (!TrueConst || (N->getSimpleValueType(0) != MVT::i64 &&
                     N->getSimpleValueType(0) != MVT::i32))
    return false;
 
  // We are looking for any of:
  // (select_cc lhs, rhs,  1, (sext (setcc [lr]hs, [lr]hs, cc2)), cc1)
  // (select_cc lhs, rhs, -1, (zext (setcc [lr]hs, [lr]hs, cc2)), cc1)
  // (select_cc lhs, rhs,  0, (select_cc [lr]hs, [lr]hs,  1, -1, cc2), seteq)
  // (select_cc lhs, rhs,  0, (select_cc [lr]hs, [lr]hs, -1,  1, cc2), seteq)
  int64_t TrueResVal = TrueConst->getSExtValue();
  if ((TrueResVal < -1 || TrueResVal > 1) ||
      (TrueResVal == -1 && FalseRes.getOpcode() != ISD::ZERO_EXTEND) ||
      (TrueResVal == 1 && FalseRes.getOpcode() != ISD::SIGN_EXTEND) ||
      (TrueResVal == 0 &&
       (FalseRes.getOpcode() != ISD::SELECT_CC || CC != ISD::SETEQ)))
    return false;
 
  SDValue SetOrSelCC = FalseRes.getOpcode() == ISD::SELECT_CC
                           ? FalseRes
                           : FalseRes.getOperand(0);
  bool InnerIsSel = SetOrSelCC.getOpcode() == ISD::SELECT_CC;
  if (SetOrSelCC.getOpcode() != ISD::SETCC &&
      SetOrSelCC.getOpcode() != ISD::SELECT_CC)
    return false;
 
  // Without this setb optimization, the outer SELECT_CC will be manually
  // selected to SELECT_CC_I4/SELECT_CC_I8 Pseudo, then expand-isel-pseudos pass
  // transforms pseudo instruction to isel instruction. When there are more than
  // one use for result like zext/sext, with current optimization we only see
  // isel is replaced by setb but can't see any significant gain. Since
  // setb has longer latency than original isel, we should avoid this. Another
  // point is that setb requires comparison always kept, it can break the
  // opportunity to get the comparison away if we have in future.
  if (!SetOrSelCC.hasOneUse() || (!InnerIsSel && !FalseRes.hasOneUse()))
    return false;
 
  SDValue InnerLHS = SetOrSelCC.getOperand(0);
  SDValue InnerRHS = SetOrSelCC.getOperand(1);
  ISD::CondCode InnerCC =
      cast<CondCodeSDNode>(SetOrSelCC.getOperand(InnerIsSel ? 4 : 2))->get();
  // If the inner comparison is a select_cc, make sure the true/false values are
  // 1/-1 and canonicalize it if needed.
  if (InnerIsSel) {
    ConstantSDNode *SelCCTrueConst =
        dyn_cast<ConstantSDNode>(SetOrSelCC.getOperand(2));
    ConstantSDNode *SelCCFalseConst =
        dyn_cast<ConstantSDNode>(SetOrSelCC.getOperand(3));
    if (!SelCCTrueConst || !SelCCFalseConst)
      return false;
    int64_t SelCCTVal = SelCCTrueConst->getSExtValue();
    int64_t SelCCFVal = SelCCFalseConst->getSExtValue();
    // The values must be -1/1 (requiring a swap) or 1/-1.
    if (SelCCTVal == -1 && SelCCFVal == 1) {
      std::swap(InnerLHS, InnerRHS);
    } else if (SelCCTVal != 1 || SelCCFVal != -1)
      return false;
  }
 
  // Canonicalize unsigned case
  if (InnerCC == ISD::SETULT || InnerCC == ISD::SETUGT) {
    IsUnCmp = true;
    InnerCC = (InnerCC == ISD::SETULT) ? ISD::SETLT : ISD::SETGT;
  }
 
  bool InnerSwapped = false;
  if (LHS == InnerRHS && RHS == InnerLHS)
    InnerSwapped = true;
  else if (LHS != InnerLHS || RHS != InnerRHS)
    return false;
 
  switch (CC) {
  // (select_cc lhs, rhs,  0, \
  //     (select_cc [lr]hs, [lr]hs, 1, -1, setlt/setgt), seteq)
  case ISD::SETEQ:
    if (!InnerIsSel)
      return false;
    if (InnerCC != ISD::SETLT && InnerCC != ISD::SETGT)
      return false;
    NeedSwapOps = (InnerCC == ISD::SETGT) ? InnerSwapped : !InnerSwapped;
    break;
 
  // (select_cc lhs, rhs, -1, (zext (setcc [lr]hs, [lr]hs, setne)), setu?lt)
  // (select_cc lhs, rhs, -1, (zext (setcc lhs, rhs, setgt)), setu?lt)
  // (select_cc lhs, rhs, -1, (zext (setcc rhs, lhs, setlt)), setu?lt)
  // (select_cc lhs, rhs, 1, (sext (setcc [lr]hs, [lr]hs, setne)), setu?lt)
  // (select_cc lhs, rhs, 1, (sext (setcc lhs, rhs, setgt)), setu?lt)
  // (select_cc lhs, rhs, 1, (sext (setcc rhs, lhs, setlt)), setu?lt)
  case ISD::SETULT:
    if (!IsUnCmp && InnerCC != ISD::SETNE)
      return false;
    IsUnCmp = true;
    [[fallthrough]];
  case ISD::SETLT:
    if (InnerCC == ISD::SETNE || (InnerCC == ISD::SETGT && !InnerSwapped) ||
        (InnerCC == ISD::SETLT && InnerSwapped))
      NeedSwapOps = (TrueResVal == 1);
    else
      return false;
    break;
 
  // (select_cc lhs, rhs, 1, (sext (setcc [lr]hs, [lr]hs, setne)), setu?gt)
  // (select_cc lhs, rhs, 1, (sext (setcc lhs, rhs, setlt)), setu?gt)
  // (select_cc lhs, rhs, 1, (sext (setcc rhs, lhs, setgt)), setu?gt)
  // (select_cc lhs, rhs, -1, (zext (setcc [lr]hs, [lr]hs, setne)), setu?gt)
  // (select_cc lhs, rhs, -1, (zext (setcc lhs, rhs, setlt)), setu?gt)
  // (select_cc lhs, rhs, -1, (zext (setcc rhs, lhs, setgt)), setu?gt)
  case ISD::SETUGT:
    if (!IsUnCmp && InnerCC != ISD::SETNE)
      return false;
    IsUnCmp = true;
    [[fallthrough]];
  case ISD::SETGT:
    if (InnerCC == ISD::SETNE || (InnerCC == ISD::SETLT && !InnerSwapped) ||
        (InnerCC == ISD::SETGT && InnerSwapped))
      NeedSwapOps = (TrueResVal == -1);
    else
      return false;
    break;
 
  default:
    return false;
  }
 
  LLVM_DEBUG(dbgs() << "Found a node that can be lowered to a SETB: ");
  LLVM_DEBUG(N->dump());
 
  return true;
}
 
// Return true if it's a software square-root/divide operand.
static bool isSWTestOp(SDValue N) {
  if (N.getOpcode() == PPCISD::FTSQRT)
    return true;
  if (N.getNumOperands() < 1 || !isa<ConstantSDNode>(N.getOperand(0)) ||
      N.getOpcode() != ISD::INTRINSIC_WO_CHAIN)
    return false;
  switch (N.getConstantOperandVal(0)) {
  case Intrinsic::ppc_vsx_xvtdivdp:
  case Intrinsic::ppc_vsx_xvtdivsp:
  case Intrinsic::ppc_vsx_xvtsqrtdp:
  case Intrinsic::ppc_vsx_xvtsqrtsp:
    return true;
  }
  return false;
}
 
bool PPCDAGToDAGISel::tryFoldSWTestBRCC(SDNode *N) {
  assert(N->getOpcode() == ISD::BR_CC && "ISD::BR_CC is expected.");
  // We are looking for following patterns, where `truncate to i1` actually has
  // the same semantic with `and 1`.
  // (br_cc seteq, (truncateToi1 SWTestOp), 0) -> (BCC PRED_NU, SWTestOp)
  // (br_cc seteq, (and SWTestOp, 2), 0) -> (BCC PRED_NE, SWTestOp)
  // (br_cc seteq, (and SWTestOp, 4), 0) -> (BCC PRED_LE, SWTestOp)
  // (br_cc seteq, (and SWTestOp, 8), 0) -> (BCC PRED_GE, SWTestOp)
  // (br_cc setne, (truncateToi1 SWTestOp), 0) -> (BCC PRED_UN, SWTestOp)
  // (br_cc setne, (and SWTestOp, 2), 0) -> (BCC PRED_EQ, SWTestOp)
  // (br_cc setne, (and SWTestOp, 4), 0) -> (BCC PRED_GT, SWTestOp)
  // (br_cc setne, (and SWTestOp, 8), 0) -> (BCC PRED_LT, SWTestOp)
  ISD::CondCode CC = cast<CondCodeSDNode>(N->getOperand(1))->get();
  if (CC != ISD::SETEQ && CC != ISD::SETNE)
    return false;
 
  SDValue CmpRHS = N->getOperand(3);
  if (!isa<ConstantSDNode>(CmpRHS) ||
      cast<ConstantSDNode>(CmpRHS)->getSExtValue() != 0)
    return false;
 
  SDValue CmpLHS = N->getOperand(2);
  if (CmpLHS.getNumOperands() < 1 || !isSWTestOp(CmpLHS.getOperand(0)))
    return false;
 
  unsigned PCC = 0;
  bool IsCCNE = CC == ISD::SETNE;
  if (CmpLHS.getOpcode() == ISD::AND &&
      isa<ConstantSDNode>(CmpLHS.getOperand(1)))
    switch (CmpLHS.getConstantOperandVal(1)) {
    case 1:
      PCC = IsCCNE ? PPC::PRED_UN : PPC::PRED_NU;
      break;
    case 2:
      PCC = IsCCNE ? PPC::PRED_EQ : PPC::PRED_NE;
      break;
    case 4:
      PCC = IsCCNE ? PPC::PRED_GT : PPC::PRED_LE;
      break;
    case 8:
      PCC = IsCCNE ? PPC::PRED_LT : PPC::PRED_GE;
      break;
    default:
      return false;
    }
  else if (CmpLHS.getOpcode() == ISD::TRUNCATE &&
           CmpLHS.getValueType() == MVT::i1)
    PCC = IsCCNE ? PPC::PRED_UN : PPC::PRED_NU;
 
  if (PCC) {
    SDLoc dl(N);
    SDValue Ops[] = {getI32Imm(PCC, dl), CmpLHS.getOperand(0), N->getOperand(4),
                     N->getOperand(0)};
    CurDAG->SelectNodeTo(N, PPC::BCC, MVT::Other, Ops);
    return true;
  }
  return false;
}
 
bool PPCDAGToDAGISel::trySelectLoopCountIntrinsic(SDNode *N) {
  // Sometimes the promoted value of the intrinsic is ANDed by some non-zero
  // value, for example when crbits is disabled. If so, select the
  // loop_decrement intrinsics now.
  ISD::CondCode CC = cast<CondCodeSDNode>(N->getOperand(1))->get();
  SDValue LHS = N->getOperand(2), RHS = N->getOperand(3);
 
  if (LHS.getOpcode() != ISD::AND || !isa<ConstantSDNode>(LHS.getOperand(1)) ||
      isNullConstant(LHS.getOperand(1)))
    return false;
 
  if (LHS.getOperand(0).getOpcode() != ISD::INTRINSIC_W_CHAIN ||
      cast<ConstantSDNode>(LHS.getOperand(0).getOperand(1))->getZExtValue() !=
          Intrinsic::loop_decrement)
    return false;
 
  if (!isa<ConstantSDNode>(RHS))
    return false;
 
  assert((CC == ISD::SETEQ || CC == ISD::SETNE) &&
         "Counter decrement comparison is not EQ or NE");
 
  SDValue OldDecrement = LHS.getOperand(0);
  assert(OldDecrement.hasOneUse() && "loop decrement has more than one use!");