VPlanRecipes.cpp

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//===- VPlanRecipes.cpp - Implementations for VPlan recipes ---------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file contains implementations for different VPlan recipes.
///
//===----------------------------------------------------------------------===//
 
#include "VPlan.h"
#include "VPlanAnalysis.h"
#include "VPlanPatternMatch.h"
#include "VPlanUtils.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Analysis/IVDescriptors.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/VectorBuilder.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/LoopUtils.h"
#include "llvm/Transforms/Utils/ScalarEvolutionExpander.h"
#include <cassert>
 
using namespace llvm;
 
using VectorParts = SmallVector<Value *, 2>;
 
namespace llvm {
extern cl::opt<bool> EnableVPlanNativePath;
}
extern cl::opt<unsigned> ForceTargetInstructionCost;
 
#define LV_NAME "loop-vectorize"
#define DEBUG_TYPE LV_NAME
 
bool VPRecipeBase::mayWriteToMemory() const {
  switch (getVPDefID()) {
  case VPInstructionSC:
    return cast<VPInstruction>(this)->opcodeMayReadOrWriteFromMemory();
  case VPInterleaveSC:
    return cast<VPInterleaveRecipe>(this)->getNumStoreOperands() > 0;
  case VPWidenStoreEVLSC:
  case VPWidenStoreSC:
    return true;
  case VPReplicateSC:
    return cast<Instruction>(getVPSingleValue()->getUnderlyingValue())
        ->mayWriteToMemory();
  case VPWidenCallSC:
    return !cast<VPWidenCallRecipe>(this)
                ->getCalledScalarFunction()
                ->onlyReadsMemory();
  case VPWidenIntrinsicSC:
    return cast<VPWidenIntrinsicRecipe>(this)->mayWriteToMemory();
  case VPBranchOnMaskSC:
  case VPScalarIVStepsSC:
  case VPPredInstPHISC:
    return false;
  case VPBlendSC:
  case VPReductionEVLSC:
  case VPReductionSC:
  case VPVectorPointerSC:
  case VPWidenCanonicalIVSC:
  case VPWidenCastSC:
  case VPWidenGEPSC:
  case VPWidenIntOrFpInductionSC:
  case VPWidenLoadEVLSC:
  case VPWidenLoadSC:
  case VPWidenPHISC:
  case VPWidenSC:
  case VPWidenEVLSC:
  case VPWidenSelectSC: {
    const Instruction *I =
        dyn_cast_or_null<Instruction>(getVPSingleValue()->getUnderlyingValue());
    (void)I;
    assert((!I || !I->mayWriteToMemory()) &&
           "underlying instruction may write to memory");
    return false;
  }
  default:
    return true;
  }
}
 
bool VPRecipeBase::mayReadFromMemory() const {
  switch (getVPDefID()) {
  case VPInstructionSC:
    return cast<VPInstruction>(this)->opcodeMayReadOrWriteFromMemory();
  case VPWidenLoadEVLSC:
  case VPWidenLoadSC:
    return true;
  case VPReplicateSC:
    return cast<Instruction>(getVPSingleValue()->getUnderlyingValue())
        ->mayReadFromMemory();
  case VPWidenCallSC:
    return !cast<VPWidenCallRecipe>(this)
                ->getCalledScalarFunction()
                ->onlyWritesMemory();
  case VPWidenIntrinsicSC:
    return cast<VPWidenIntrinsicRecipe>(this)->mayReadFromMemory();
  case VPBranchOnMaskSC:
  case VPPredInstPHISC:
  case VPScalarIVStepsSC:
  case VPWidenStoreEVLSC:
  case VPWidenStoreSC:
    return false;
  case VPBlendSC:
  case VPReductionEVLSC:
  case VPReductionSC:
  case VPVectorPointerSC:
  case VPWidenCanonicalIVSC:
  case VPWidenCastSC:
  case VPWidenGEPSC:
  case VPWidenIntOrFpInductionSC:
  case VPWidenPHISC:
  case VPWidenSC:
  case VPWidenEVLSC:
  case VPWidenSelectSC: {
    const Instruction *I =
        dyn_cast_or_null<Instruction>(getVPSingleValue()->getUnderlyingValue());
    (void)I;
    assert((!I || !I->mayReadFromMemory()) &&
           "underlying instruction may read from memory");
    return false;
  }
  default:
    return true;
  }
}
 
bool VPRecipeBase::mayHaveSideEffects() const {
  switch (getVPDefID()) {
  case VPDerivedIVSC:
  case VPPredInstPHISC:
  case VPScalarCastSC:
  case VPReverseVectorPointerSC:
    return false;
  case VPInstructionSC:
    return mayWriteToMemory();
  case VPWidenCallSC: {
    Function *Fn = cast<VPWidenCallRecipe>(this)->getCalledScalarFunction();
    return mayWriteToMemory() || !Fn->doesNotThrow() || !Fn->willReturn();
  }
  case VPWidenIntrinsicSC:
    return cast<VPWidenIntrinsicRecipe>(this)->mayHaveSideEffects();
  case VPBlendSC:
  case VPReductionEVLSC:
  case VPReductionSC:
  case VPScalarIVStepsSC:
  case VPVectorPointerSC:
  case VPWidenCanonicalIVSC:
  case VPWidenCastSC:
  case VPWidenGEPSC:
  case VPWidenIntOrFpInductionSC:
  case VPWidenPHISC:
  case VPWidenPointerInductionSC:
  case VPWidenSC:
  case VPWidenEVLSC:
  case VPWidenSelectSC: {
    const Instruction *I =
        dyn_cast_or_null<Instruction>(getVPSingleValue()->getUnderlyingValue());
    (void)I;
    assert((!I || !I->mayHaveSideEffects()) &&
           "underlying instruction has side-effects");
    return false;
  }
  case VPInterleaveSC:
    return mayWriteToMemory();
  case VPWidenLoadEVLSC:
  case VPWidenLoadSC:
  case VPWidenStoreEVLSC:
  case VPWidenStoreSC:
    assert(
        cast<VPWidenMemoryRecipe>(this)->getIngredient().mayHaveSideEffects() ==
            mayWriteToMemory() &&
        "mayHaveSideffects result for ingredient differs from this "
        "implementation");
    return mayWriteToMemory();
  case VPReplicateSC: {
    auto *R = cast<VPReplicateRecipe>(this);
    return R->getUnderlyingInstr()->mayHaveSideEffects();
  }
  default:
    return true;
  }
}
 
void VPRecipeBase::insertBefore(VPRecipeBase *InsertPos) {
  assert(!Parent && "Recipe already in some VPBasicBlock");
  assert(InsertPos->getParent() &&
         "Insertion position not in any VPBasicBlock");
  InsertPos->getParent()->insert(this, InsertPos->getIterator());
}
 
void VPRecipeBase::insertBefore(VPBasicBlock &BB,
                                iplist<VPRecipeBase>::iterator I) {
  assert(!Parent && "Recipe already in some VPBasicBlock");
  assert(I == BB.end() || I->getParent() == &BB);
  BB.insert(this, I);
}
 
void VPRecipeBase::insertAfter(VPRecipeBase *InsertPos) {
  assert(!Parent && "Recipe already in some VPBasicBlock");
  assert(InsertPos->getParent() &&
         "Insertion position not in any VPBasicBlock");
  InsertPos->getParent()->insert(this, std::next(InsertPos->getIterator()));
}
 
void VPRecipeBase::removeFromParent() {
  assert(getParent() && "Recipe not in any VPBasicBlock");
  getParent()->getRecipeList().remove(getIterator());
  Parent = nullptr;
}
 
iplist<VPRecipeBase>::iterator VPRecipeBase::eraseFromParent() {
  assert(getParent() && "Recipe not in any VPBasicBlock");
  return getParent()->getRecipeList().erase(getIterator());
}
 
void VPRecipeBase::moveAfter(VPRecipeBase *InsertPos) {
  removeFromParent();
  insertAfter(InsertPos);
}
 
void VPRecipeBase::moveBefore(VPBasicBlock &BB,
                              iplist<VPRecipeBase>::iterator I) {
  removeFromParent();
  insertBefore(BB, I);
}
 
InstructionCost VPRecipeBase::cost(ElementCount VF, VPCostContext &Ctx) {
  // Get the underlying instruction for the recipe, if there is one. It is used
  // to
  //   * decide if cost computation should be skipped for this recipe,
  //   * apply forced target instruction cost.
  Instruction *UI = nullptr;
  if (auto *S = dyn_cast<VPSingleDefRecipe>(this))
    UI = dyn_cast_or_null<Instruction>(S->getUnderlyingValue());
  else if (auto *IG = dyn_cast<VPInterleaveRecipe>(this))
    UI = IG->getInsertPos();
  else if (auto *WidenMem = dyn_cast<VPWidenMemoryRecipe>(this))
    UI = &WidenMem->getIngredient();
 
  InstructionCost RecipeCost;
  if (UI && Ctx.skipCostComputation(UI, VF.isVector())) {
    RecipeCost = 0;
  } else {
    RecipeCost = computeCost(VF, Ctx);
    if (UI && ForceTargetInstructionCost.getNumOccurrences() > 0 &&
        RecipeCost.isValid())
      RecipeCost = InstructionCost(ForceTargetInstructionCost);
  }
 
  LLVM_DEBUG({
    dbgs() << "Cost of " << RecipeCost << " for VF " << VF << ": ";
    dump();
  });
  return RecipeCost;
}
 
InstructionCost VPRecipeBase::computeCost(ElementCount VF,
                                          VPCostContext &Ctx) const {
  llvm_unreachable("subclasses should implement computeCost");
}
 
FastMathFlags VPRecipeWithIRFlags::getFastMathFlags() const {
  assert(OpType == OperationType::FPMathOp &&
         "recipe doesn't have fast math flags");
  FastMathFlags Res;
  Res.setAllowReassoc(FMFs.AllowReassoc);
  Res.setNoNaNs(FMFs.NoNaNs);
  Res.setNoInfs(FMFs.NoInfs);
  Res.setNoSignedZeros(FMFs.NoSignedZeros);
  Res.setAllowReciprocal(FMFs.AllowReciprocal);
  Res.setAllowContract(FMFs.AllowContract);
  Res.setApproxFunc(FMFs.ApproxFunc);
  return Res;
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPSingleDefRecipe::dump() const { VPDef::dump(); }
#endif
 
template <unsigned PartOpIdx>
VPValue *
VPUnrollPartAccessor<PartOpIdx>::getUnrollPartOperand(VPUser &U) const {
  if (U.getNumOperands() == PartOpIdx + 1)
    return U.getOperand(PartOpIdx);
  return nullptr;
}
 
template <unsigned PartOpIdx>
unsigned VPUnrollPartAccessor<PartOpIdx>::getUnrollPart(VPUser &U) const {
  if (auto *UnrollPartOp = getUnrollPartOperand(U))
    return cast<ConstantInt>(UnrollPartOp->getLiveInIRValue())->getZExtValue();
  return 0;
}
 
VPInstruction::VPInstruction(unsigned Opcode, CmpInst::Predicate Pred,
                             VPValue *A, VPValue *B, DebugLoc DL,
                             const Twine &Name)
    : VPRecipeWithIRFlags(VPDef::VPInstructionSC, ArrayRef<VPValue *>({A, B}),
                          Pred, DL),
      Opcode(Opcode), Name(Name.str()) {
  assert(Opcode == Instruction::ICmp &&
         "only ICmp predicates supported at the moment");
}
 
VPInstruction::VPInstruction(unsigned Opcode,
                             std::initializer_list<VPValue *> Operands,
                             FastMathFlags FMFs, DebugLoc DL, const Twine &Name)
    : VPRecipeWithIRFlags(VPDef::VPInstructionSC, Operands, FMFs, DL),
      Opcode(Opcode), Name(Name.str()) {
  // Make sure the VPInstruction is a floating-point operation.
  assert(isFPMathOp() && "this op can't take fast-math flags");
}
 
bool VPInstruction::doesGeneratePerAllLanes() const {
  return Opcode == VPInstruction::PtrAdd && !vputils::onlyFirstLaneUsed(this);
}
 
bool VPInstruction::canGenerateScalarForFirstLane() const {
  if (Instruction::isBinaryOp(getOpcode()))
    return true;
  if (isSingleScalar() || isVectorToScalar())
    return true;
  switch (Opcode) {
  case Instruction::ICmp:
  case Instruction::Select:
  case VPInstruction::BranchOnCond:
  case VPInstruction::BranchOnCount:
  case VPInstruction::CalculateTripCountMinusVF:
  case VPInstruction::CanonicalIVIncrementForPart:
  case VPInstruction::PtrAdd:
  case VPInstruction::ExplicitVectorLength:
  case VPInstruction::AnyOf:
    return true;
  default:
    return false;
  }
}
 
Value *VPInstruction::generatePerLane(VPTransformState &State,
                                      const VPLane &Lane) {
  IRBuilderBase &Builder = State.Builder;
 
  assert(getOpcode() == VPInstruction::PtrAdd &&
         "only PtrAdd opcodes are supported for now");
  return Builder.CreatePtrAdd(State.get(getOperand(0), Lane),
                              State.get(getOperand(1), Lane), Name);
}
 
Value *VPInstruction::generate(VPTransformState &State) {
  IRBuilderBase &Builder = State.Builder;
 
  if (Instruction::isBinaryOp(getOpcode())) {
    bool OnlyFirstLaneUsed = vputils::onlyFirstLaneUsed(this);
    Value *A = State.get(getOperand(0), OnlyFirstLaneUsed);
    Value *B = State.get(getOperand(1), OnlyFirstLaneUsed);
    auto *Res =
        Builder.CreateBinOp((Instruction::BinaryOps)getOpcode(), A, B, Name);
    if (auto *I = dyn_cast<Instruction>(Res))
      setFlags(I);
    return Res;
  }
 
  switch (getOpcode()) {
  case VPInstruction::Not: {
    Value *A = State.get(getOperand(0));
    return Builder.CreateNot(A, Name);
  }
  case Instruction::ICmp: {
    bool OnlyFirstLaneUsed = vputils::onlyFirstLaneUsed(this);
    Value *A = State.get(getOperand(0), OnlyFirstLaneUsed);
    Value *B = State.get(getOperand(1), OnlyFirstLaneUsed);
    return Builder.CreateCmp(getPredicate(), A, B, Name);
  }
  case Instruction::Select: {
    bool OnlyFirstLaneUsed = vputils::onlyFirstLaneUsed(this);
    Value *Cond = State.get(getOperand(0), OnlyFirstLaneUsed);
    Value *Op1 = State.get(getOperand(1), OnlyFirstLaneUsed);
    Value *Op2 = State.get(getOperand(2), OnlyFirstLaneUsed);
    return Builder.CreateSelect(Cond, Op1, Op2, Name);
  }
  case VPInstruction::ActiveLaneMask: {
    // Get first lane of vector induction variable.
    Value *VIVElem0 = State.get(getOperand(0), VPLane(0));
    // Get the original loop tripcount.
    Value *ScalarTC = State.get(getOperand(1), VPLane(0));
 
    // If this part of the active lane mask is scalar, generate the CMP directly
    // to avoid unnecessary extracts.
    if (State.VF.isScalar())
      return Builder.CreateCmp(CmpInst::Predicate::ICMP_ULT, VIVElem0, ScalarTC,
                               Name);
 
    auto *Int1Ty = Type::getInt1Ty(Builder.getContext());
    auto *PredTy = VectorType::get(Int1Ty, State.VF);
    return Builder.CreateIntrinsic(Intrinsic::get_active_lane_mask,
                                   {PredTy, ScalarTC->getType()},
                                   {VIVElem0, ScalarTC}, nullptr, Name);
  }
  case VPInstruction::FirstOrderRecurrenceSplice: {
    // Generate code to combine the previous and current values in vector v3.
    //
    //   vector.ph:
    //     v_init = vector(..., ..., ..., a[-1])
    //     br vector.body
    //
    //   vector.body
    //     i = phi [0, vector.ph], [i+4, vector.body]
    //     v1 = phi [v_init, vector.ph], [v2, vector.body]
    //     v2 = a[i, i+1, i+2, i+3];
    //     v3 = vector(v1(3), v2(0, 1, 2))
 
    auto *V1 = State.get(getOperand(0));
    if (!V1->getType()->isVectorTy())
      return V1;
    Value *V2 = State.get(getOperand(1));
    return Builder.CreateVectorSplice(V1, V2, -1, Name);
  }
  case VPInstruction::CalculateTripCountMinusVF: {
    unsigned UF = getParent()->getPlan()->getUF();
    Value *ScalarTC = State.get(getOperand(0), VPLane(0));
    Value *Step = createStepForVF(Builder, ScalarTC->getType(), State.VF, UF);
    Value *Sub = Builder.CreateSub(ScalarTC, Step);
    Value *Cmp = Builder.CreateICmp(CmpInst::Predicate::ICMP_UGT, ScalarTC, Step);
    Value *Zero = ConstantInt::get(ScalarTC->getType(), 0);
    return Builder.CreateSelect(Cmp, Sub, Zero);
  }
  case VPInstruction::ExplicitVectorLength: {
    // TODO: Restructure this code with an explicit remainder loop, vsetvli can
    // be outside of the main loop.
    Value *AVL = State.get(getOperand(0), /*IsScalar*/ true);
    // Compute EVL
    assert(AVL->getType()->isIntegerTy() &&
           "Requested vector length should be an integer.");
 
    assert(State.VF.isScalable() && "Expected scalable vector factor.");
    Value *VFArg = State.Builder.getInt32(State.VF.getKnownMinValue());
 
    Value *EVL = State.Builder.CreateIntrinsic(
        State.Builder.getInt32Ty(), Intrinsic::experimental_get_vector_length,
        {AVL, VFArg, State.Builder.getTrue()});
    return EVL;
  }
  case VPInstruction::CanonicalIVIncrementForPart: {
    unsigned Part = getUnrollPart(*this);
    auto *IV = State.get(getOperand(0), VPLane(0));
    assert(Part != 0 && "Must have a positive part");
    // The canonical IV is incremented by the vectorization factor (num of
    // SIMD elements) times the unroll part.
    Value *Step = createStepForVF(Builder, IV->getType(), State.VF, Part);
    return Builder.CreateAdd(IV, Step, Name, hasNoUnsignedWrap(),
                             hasNoSignedWrap());
  }
  case VPInstruction::BranchOnCond: {
    Value *Cond = State.get(getOperand(0), VPLane(0));
    // Replace the temporary unreachable terminator with a new conditional
    // branch, hooking it up to backward destination for exiting blocks now and
    // to forward destination(s) later when they are created.
    BranchInst *CondBr =
        Builder.CreateCondBr(Cond, Builder.GetInsertBlock(), nullptr);
    CondBr->setSuccessor(0, nullptr);
    Builder.GetInsertBlock()->getTerminator()->eraseFromParent();
 
    if (!getParent()->isExiting())
      return CondBr;
 
    VPRegionBlock *ParentRegion = getParent()->getParent();
    VPBasicBlock *Header = ParentRegion->getEntryBasicBlock();
    CondBr->setSuccessor(1, State.CFG.VPBB2IRBB[Header]);
    return CondBr;
  }
  case VPInstruction::BranchOnCount: {
    // First create the compare.
    Value *IV = State.get(getOperand(0), /*IsScalar*/ true);
    Value *TC = State.get(getOperand(1), /*IsScalar*/ true);
    Value *Cond = Builder.CreateICmpEQ(IV, TC);
 
    // Now create the branch.
    auto *Plan = getParent()->getPlan();
    VPRegionBlock *TopRegion = Plan->getVectorLoopRegion();
    VPBasicBlock *Header = TopRegion->getEntry()->getEntryBasicBlock();
 
    // Replace the temporary unreachable terminator with a new conditional
    // branch, hooking it up to backward destination (the header) now and to the
    // forward destination (the exit/middle block) later when it is created.
    // Note that CreateCondBr expects a valid BB as first argument, so we need
    // to set it to nullptr later.
    BranchInst *CondBr = Builder.CreateCondBr(Cond, Builder.GetInsertBlock(),
                                              State.CFG.VPBB2IRBB[Header]);
    CondBr->setSuccessor(0, nullptr);
    Builder.GetInsertBlock()->getTerminator()->eraseFromParent();
    return CondBr;
  }
  case VPInstruction::ComputeReductionResult: {
    // FIXME: The cross-recipe dependency on VPReductionPHIRecipe is temporary
    // and will be removed by breaking up the recipe further.
    auto *PhiR = cast<VPReductionPHIRecipe>(getOperand(0));
    auto *OrigPhi = cast<PHINode>(PhiR->getUnderlyingValue());
    // Get its reduction variable descriptor.
    const RecurrenceDescriptor &RdxDesc = PhiR->getRecurrenceDescriptor();
 
    RecurKind RK = RdxDesc.getRecurrenceKind();
 
    Type *PhiTy = OrigPhi->getType();
    // The recipe's operands are the reduction phi, followed by one operand for
    // each part of the reduction.
    unsigned UF = getNumOperands() - 1;
    VectorParts RdxParts(UF);
    for (unsigned Part = 0; Part < UF; ++Part)
      RdxParts[Part] = State.get(getOperand(1 + Part), PhiR->isInLoop());
 
    // If the vector reduction can be performed in a smaller type, we truncate
    // then extend the loop exit value to enable InstCombine to evaluate the
    // entire expression in the smaller type.
    // TODO: Handle this in truncateToMinBW.
    if (State.VF.isVector() && PhiTy != RdxDesc.getRecurrenceType()) {
      Type *RdxVecTy = VectorType::get(RdxDesc.getRecurrenceType(), State.VF);
      for (unsigned Part = 0; Part < UF; ++Part)
        RdxParts[Part] = Builder.CreateTrunc(RdxParts[Part], RdxVecTy);
    }
    // Reduce all of the unrolled parts into a single vector.
    Value *ReducedPartRdx = RdxParts[0];
    unsigned Op = RdxDesc.getOpcode();
    if (RecurrenceDescriptor::isAnyOfRecurrenceKind(RK))
      Op = Instruction::Or;
 
    if (PhiR->isOrdered()) {
      ReducedPartRdx = RdxParts[UF - 1];
    } else {
      // Floating-point operations should have some FMF to enable the reduction.
      IRBuilderBase::FastMathFlagGuard FMFG(Builder);
      Builder.setFastMathFlags(RdxDesc.getFastMathFlags());
      for (unsigned Part = 1; Part < UF; ++Part) {
        Value *RdxPart = RdxParts[Part];
        if (Op != Instruction::ICmp && Op != Instruction::FCmp)
          ReducedPartRdx = Builder.CreateBinOp(
              (Instruction::BinaryOps)Op, RdxPart, ReducedPartRdx, "bin.rdx");
        else if (RecurrenceDescriptor::isFindLastIVRecurrenceKind(RK))
          ReducedPartRdx =
              createMinMaxOp(Builder, RecurKind::SMax, ReducedPartRdx, RdxPart);
        else
          ReducedPartRdx = createMinMaxOp(Builder, RK, ReducedPartRdx, RdxPart);
      }
    }
 
    // Create the reduction after the loop. Note that inloop reductions create
    // the target reduction in the loop using a Reduction recipe.
    if ((State.VF.isVector() ||
         RecurrenceDescriptor::isAnyOfRecurrenceKind(RK) ||
         RecurrenceDescriptor::isFindLastIVRecurrenceKind(RK)) &&
        !PhiR->isInLoop()) {
      ReducedPartRdx =
          createReduction(Builder, RdxDesc, ReducedPartRdx, OrigPhi);
      // If the reduction can be performed in a smaller type, we need to extend
      // the reduction to the wider type before we branch to the original loop.
      if (PhiTy != RdxDesc.getRecurrenceType())
        ReducedPartRdx = RdxDesc.isSigned()
                             ? Builder.CreateSExt(ReducedPartRdx, PhiTy)
                             : Builder.CreateZExt(ReducedPartRdx, PhiTy);
    }
 
    return ReducedPartRdx;
  }
  case VPInstruction::ExtractFromEnd: {
    auto *CI = cast<ConstantInt>(getOperand(1)->getLiveInIRValue());
    unsigned Offset = CI->getZExtValue();
    assert(Offset > 0 && "Offset from end must be positive");
    Value *Res;
    if (State.VF.isVector()) {
      assert(Offset <= State.VF.getKnownMinValue() &&
             "invalid offset to extract from");
      // Extract lane VF - Offset from the operand.
      Res = State.get(getOperand(0), VPLane::getLaneFromEnd(State.VF, Offset));
    } else {
      assert(Offset <= 1 && "invalid offset to extract from");
      Res = State.get(getOperand(0));
    }
    if (isa<ExtractElementInst>(Res))
      Res->setName(Name);
    return Res;
  }
  case VPInstruction::LogicalAnd: {
    Value *A = State.get(getOperand(0));
    Value *B = State.get(getOperand(1));
    return Builder.CreateLogicalAnd(A, B, Name);
  }
  case VPInstruction::PtrAdd: {
    assert(vputils::onlyFirstLaneUsed(this) &&
           "can only generate first lane for PtrAdd");
    Value *Ptr = State.get(getOperand(0), VPLane(0));
    Value *Addend = State.get(getOperand(1), VPLane(0));
    return Builder.CreatePtrAdd(Ptr, Addend, Name, getGEPNoWrapFlags());
  }
  case VPInstruction::ResumePhi: {
    Value *IncomingFromVPlanPred =
        State.get(getOperand(0), /* IsScalar */ true);
    Value *IncomingFromOtherPreds =
        State.get(getOperand(1), /* IsScalar */ true);
    auto *NewPhi =
        Builder.CreatePHI(State.TypeAnalysis.inferScalarType(this), 2, Name);
    BasicBlock *VPlanPred =
        State.CFG
            .VPBB2IRBB[cast<VPBasicBlock>(getParent()->getPredecessors()[0])];
    NewPhi->addIncoming(IncomingFromVPlanPred, VPlanPred);
    for (auto *OtherPred : predecessors(Builder.GetInsertBlock())) {
      if (OtherPred == VPlanPred)
        continue;
      NewPhi->addIncoming(IncomingFromOtherPreds, OtherPred);
    }
    return NewPhi;
  }
  case VPInstruction::AnyOf: {
    Value *A = State.get(getOperand(0));
    return Builder.CreateOrReduce(A);
  }
 
  default:
    llvm_unreachable("Unsupported opcode for instruction");
  }
}
 
bool VPInstruction::isVectorToScalar() const {
  return getOpcode() == VPInstruction::ExtractFromEnd ||
         getOpcode() == VPInstruction::ComputeReductionResult ||
         getOpcode() == VPInstruction::AnyOf;
}
 
bool VPInstruction::isSingleScalar() const {
  return getOpcode() == VPInstruction::ResumePhi;
}
 
#if !defined(NDEBUG)
bool VPInstruction::isFPMathOp() const {
  // Inspired by FPMathOperator::classof. Notable differences are that we don't
  // support Call, PHI and Select opcodes here yet.
  return Opcode == Instruction::FAdd || Opcode == Instruction::FMul ||
         Opcode == Instruction::FNeg || Opcode == Instruction::FSub ||
         Opcode == Instruction::FDiv || Opcode == Instruction::FRem ||
         Opcode == Instruction::FCmp || Opcode == Instruction::Select;
}
#endif
 
void VPInstruction::execute(VPTransformState &State) {
  assert(!State.Lane && "VPInstruction executing an Lane");
  IRBuilderBase::FastMathFlagGuard FMFGuard(State.Builder);
  assert((hasFastMathFlags() == isFPMathOp() ||
          getOpcode() == Instruction::Select) &&
         "Recipe not a FPMathOp but has fast-math flags?");
  if (hasFastMathFlags())
    State.Builder.setFastMathFlags(getFastMathFlags());
  State.setDebugLocFrom(getDebugLoc());
  bool GeneratesPerFirstLaneOnly = canGenerateScalarForFirstLane() &&
                                   (vputils::onlyFirstLaneUsed(this) ||
                                    isVectorToScalar() || isSingleScalar());
  bool GeneratesPerAllLanes = doesGeneratePerAllLanes();
  if (GeneratesPerAllLanes) {
    for (unsigned Lane = 0, NumLanes = State.VF.getKnownMinValue();
         Lane != NumLanes; ++Lane) {
      Value *GeneratedValue = generatePerLane(State, VPLane(Lane));
      assert(GeneratedValue && "generatePerLane must produce a value");
      State.set(this, GeneratedValue, VPLane(Lane));
    }
    return;
  }
 
  Value *GeneratedValue = generate(State);
  if (!hasResult())
    return;
  assert(GeneratedValue && "generate must produce a value");
  assert(
      (GeneratedValue->getType()->isVectorTy() == !GeneratesPerFirstLaneOnly ||
       State.VF.isScalar()) &&
      "scalar value but not only first lane defined");
  State.set(this, GeneratedValue,
            /*IsScalar*/ GeneratesPerFirstLaneOnly);
}
 
bool VPInstruction::opcodeMayReadOrWriteFromMemory() const {
  if (Instruction::isBinaryOp(getOpcode()))
    return false;
  switch (getOpcode()) {
  case Instruction::ICmp:
  case Instruction::Select:
  case VPInstruction::AnyOf:
  case VPInstruction::CalculateTripCountMinusVF:
  case VPInstruction::CanonicalIVIncrementForPart:
  case VPInstruction::ExtractFromEnd:
  case VPInstruction::FirstOrderRecurrenceSplice:
  case VPInstruction::LogicalAnd:
  case VPInstruction::Not:
  case VPInstruction::PtrAdd:
    return false;
  default:
    return true;
  }
}
 
bool VPInstruction::onlyFirstLaneUsed(const VPValue *Op) const {
  assert(is_contained(operands(), Op) && "Op must be an operand of the recipe");
  if (Instruction::isBinaryOp(getOpcode()))
    return vputils::onlyFirstLaneUsed(this);
 
  switch (getOpcode()) {
  default:
    return false;
  case Instruction::ICmp:
  case Instruction::Select:
  case Instruction::Or:
  case VPInstruction::PtrAdd:
    // TODO: Cover additional opcodes.
    return vputils::onlyFirstLaneUsed(this);
  case VPInstruction::ActiveLaneMask:
  case VPInstruction::ExplicitVectorLength:
  case VPInstruction::CalculateTripCountMinusVF:
  case VPInstruction::CanonicalIVIncrementForPart:
  case VPInstruction::BranchOnCount:
  case VPInstruction::BranchOnCond:
  case VPInstruction::ResumePhi:
    return true;
  };
  llvm_unreachable("switch should return");
}
 
bool VPInstruction::onlyFirstPartUsed(const VPValue *Op) const {
  assert(is_contained(operands(), Op) && "Op must be an operand of the recipe");
  if (Instruction::isBinaryOp(getOpcode()))
    return vputils::onlyFirstPartUsed(this);
 
  switch (getOpcode()) {
  default:
    return false;
  case Instruction::ICmp:
  case Instruction::Select:
    return vputils::onlyFirstPartUsed(this);
  case VPInstruction::BranchOnCount:
  case VPInstruction::BranchOnCond:
  case VPInstruction::CanonicalIVIncrementForPart:
    return true;
  };
  llvm_unreachable("switch should return");
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPInstruction::dump() const {
  VPSlotTracker SlotTracker(getParent()->getPlan());
  print(dbgs(), "", SlotTracker);
}
 
void VPInstruction::print(raw_ostream &O, const Twine &Indent,
                          VPSlotTracker &SlotTracker) const {
  O << Indent << "EMIT ";
 
  if (hasResult()) {
    printAsOperand(O, SlotTracker);
    O << " = ";
  }
 
  switch (getOpcode()) {
  case VPInstruction::Not:
    O << "not";
    break;
  case VPInstruction::SLPLoad:
    O << "combined load";
    break;
  case VPInstruction::SLPStore:
    O << "combined store";
    break;
  case VPInstruction::ActiveLaneMask:
    O << "active lane mask";
    break;
  case VPInstruction::ResumePhi:
    O << "resume-phi";
    break;
  case VPInstruction::ExplicitVectorLength:
    O << "EXPLICIT-VECTOR-LENGTH";
    break;
  case VPInstruction::FirstOrderRecurrenceSplice:
    O << "first-order splice";
    break;
  case VPInstruction::BranchOnCond:
    O << "branch-on-cond";
    break;
  case VPInstruction::CalculateTripCountMinusVF:
    O << "TC > VF ? TC - VF : 0";
    break;
  case VPInstruction::CanonicalIVIncrementForPart:
    O << "VF * Part +";
    break;
  case VPInstruction::BranchOnCount:
    O << "branch-on-count";
    break;
  case VPInstruction::ExtractFromEnd:
    O << "extract-from-end";
    break;
  case VPInstruction::ComputeReductionResult:
    O << "compute-reduction-result";
    break;
  case VPInstruction::LogicalAnd:
    O << "logical-and";
    break;
  case VPInstruction::PtrAdd:
    O << "ptradd";
    break;
  case VPInstruction::AnyOf:
    O << "any-of";
    break;
  default:
    O << Instruction::getOpcodeName(getOpcode());
  }
 
  printFlags(O);
  printOperands(O, SlotTracker);
 
  if (auto DL = getDebugLoc()) {
    O << ", !dbg ";
    DL.print(O);
  }
}
#endif
 
void VPIRInstruction::execute(VPTransformState &State) {
  assert((isa<PHINode>(&I) || getNumOperands() == 0) &&
         "Only PHINodes can have extra operands");
  for (const auto &[Idx, Op] : enumerate(operands())) {
    VPValue *ExitValue = Op;
    auto Lane = vputils::isUniformAfterVectorization(ExitValue)
                    ? VPLane::getFirstLane()
                    : VPLane::getLastLaneForVF(State.VF);
    VPBlockBase *Pred = getParent()->getPredecessors()[Idx];
    auto *PredVPBB = Pred->getExitingBasicBlock();
    BasicBlock *PredBB = State.CFG.VPBB2IRBB[PredVPBB];
    // Set insertion point in PredBB in case an extract needs to be generated.
    // TODO: Model extracts explicitly.
    State.Builder.SetInsertPoint(PredBB, PredBB->getFirstNonPHIIt());
    Value *V = State.get(ExitValue, VPLane(Lane));
    auto *Phi = cast<PHINode>(&I);
    // If there is no existing block for PredBB in the phi, add a new incoming
    // value. Otherwise update the existing incoming value for PredBB.
    if (Phi->getBasicBlockIndex(PredBB) == -1)
      Phi->addIncoming(V, PredBB);
    else
      Phi->setIncomingValueForBlock(PredBB, V);
  }
 
  // Advance the insert point after the wrapped IR instruction. This allows
  // interleaving VPIRInstructions and other recipes.
  State.Builder.SetInsertPoint(I.getParent(), std::next(I.getIterator()));
}
 
InstructionCost VPIRInstruction::computeCost(ElementCount VF,
                                             VPCostContext &Ctx) const {
  // The recipe wraps an existing IR instruction on the border of VPlan's scope,
  // hence it does not contribute to the cost-modeling for the VPlan.
  return 0;
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPIRInstruction::print(raw_ostream &O, const Twine &Indent,
                            VPSlotTracker &SlotTracker) const {
  O << Indent << "IR " << I;
 
  if (getNumOperands() != 0) {
    O << " (extra operand" << (getNumOperands() > 1 ? "s" : "") << ": ";
    interleaveComma(
        enumerate(operands()), O, [this, &O, &SlotTracker](auto Op) {
          Op.value()->printAsOperand(O, SlotTracker);
          O << " from ";
          getParent()->getPredecessors()[Op.index()]->printAsOperand(O);
        });
    O << ")";
  }
}
#endif
 
void VPWidenCallRecipe::execute(VPTransformState &State) {
  assert(State.VF.isVector() && "not widening");
  State.setDebugLocFrom(getDebugLoc());
 
  FunctionType *VFTy = Variant->getFunctionType();
  // Add return type if intrinsic is overloaded on it.
  SmallVector<Value *, 4> Args;
  for (const auto &I : enumerate(arg_operands())) {
    Value *Arg;
    // Some vectorized function variants may also take a scalar argument,
    // e.g. linear parameters for pointers. This needs to be the scalar value
    // from the start of the respective part when interleaving.
    if (!VFTy->getParamType(I.index())->isVectorTy())
      Arg = State.get(I.value(), VPLane(0));
    else
      Arg = State.get(I.value(), onlyFirstLaneUsed(I.value()));
    Args.push_back(Arg);
  }
 
  assert(Variant != nullptr && "Can't create vector function.");
 
  auto *CI = cast_or_null<CallInst>(getUnderlyingValue());
  SmallVector<OperandBundleDef, 1> OpBundles;
  if (CI)
    CI->getOperandBundlesAsDefs(OpBundles);
 
  CallInst *V = State.Builder.CreateCall(Variant, Args, OpBundles);
  setFlags(V);
 
  if (!V->getType()->isVoidTy())
    State.set(this, V);
  State.addMetadata(V, CI);
}
 
InstructionCost VPWidenCallRecipe::computeCost(ElementCount VF,
                                               VPCostContext &Ctx) const {
  TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
  return Ctx.TTI.getCallInstrCost(nullptr, Variant->getReturnType(),
                                  Variant->getFunctionType()->params(),
                                  CostKind);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPWidenCallRecipe::print(raw_ostream &O, const Twine &Indent,
                              VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN-CALL ";
 
  Function *CalledFn = getCalledScalarFunction();
  if (CalledFn->getReturnType()->isVoidTy())
    O << "void ";
  else {
    printAsOperand(O, SlotTracker);
    O << " = ";
  }
 
  O << "call";
  printFlags(O);
  O << " @" << CalledFn->getName() << "(";
  interleaveComma(arg_operands(), O, [&O, &SlotTracker](VPValue *Op) {
    Op->printAsOperand(O, SlotTracker);
  });
  O << ")";
 
  O << " (using library function";
  if (Variant->hasName())
    O << ": " << Variant->getName();
  O << ")";
}
#endif
 
void VPWidenIntrinsicRecipe::execute(VPTransformState &State) {
  assert(State.VF.isVector() && "not widening");
  State.setDebugLocFrom(getDebugLoc());
 
  SmallVector<Type *, 2> TysForDecl;
  // Add return type if intrinsic is overloaded on it.
  if (isVectorIntrinsicWithOverloadTypeAtArg(VectorIntrinsicID, -1, State.TTI))
    TysForDecl.push_back(VectorType::get(getResultType(), State.VF));
  SmallVector<Value *, 4> Args;
  for (const auto &I : enumerate(operands())) {
    // Some intrinsics have a scalar argument - don't replace it with a
    // vector.
    Value *Arg;
    if (isVectorIntrinsicWithScalarOpAtArg(VectorIntrinsicID, I.index(),
                                           State.TTI))
      Arg = State.get(I.value(), VPLane(0));
    else
      Arg = State.get(I.value(), onlyFirstLaneUsed(I.value()));
    if (isVectorIntrinsicWithOverloadTypeAtArg(VectorIntrinsicID, I.index(),
                                               State.TTI))
      TysForDecl.push_back(Arg->getType());
    Args.push_back(Arg);
  }
 
  // Use vector version of the intrinsic.
  Module *M = State.Builder.GetInsertBlock()->getModule();
  Function *VectorF =
      Intrinsic::getOrInsertDeclaration(M, VectorIntrinsicID, TysForDecl);
  assert(VectorF &&
         "Can't retrieve vector intrinsic or vector-predication intrinsics.");
 
  auto *CI = cast_or_null<CallInst>(getUnderlyingValue());
  SmallVector<OperandBundleDef, 1> OpBundles;
  if (CI)
    CI->getOperandBundlesAsDefs(OpBundles);
 
  CallInst *V = State.Builder.CreateCall(VectorF, Args, OpBundles);
 
  setFlags(V);
 
  if (!V->getType()->isVoidTy())
    State.set(this, V);
  State.addMetadata(V, CI);
}
 
InstructionCost VPWidenIntrinsicRecipe::computeCost(ElementCount VF,
                                                    VPCostContext &Ctx) const {
  TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
 
  // Some backends analyze intrinsic arguments to determine cost. Use the
  // underlying value for the operand if it has one. Otherwise try to use the
  // operand of the underlying call instruction, if there is one. Otherwise
  // clear Arguments.
  // TODO: Rework TTI interface to be independent of concrete IR values.
  SmallVector<const Value *> Arguments;
  for (const auto &[Idx, Op] : enumerate(operands())) {
    auto *V = Op->getUnderlyingValue();
    if (!V) {
      // Push all the VP Intrinsic's ops into the Argments even if is nullptr.
      // Some VP Intrinsic's cost will assert the number of parameters.
      // Mainly appears in the following two scenarios:
      // 1. EVL Op is nullptr
      // 2. The Argmunt of the VP Intrinsic is also the VP Intrinsic
      if (VPIntrinsic::isVPIntrinsic(VectorIntrinsicID)) {
        Arguments.push_back(V);
        continue;
      }
      if (auto *UI = dyn_cast_or_null<CallBase>(getUnderlyingValue())) {
        Arguments.push_back(UI->getArgOperand(Idx));
        continue;
      }
      Arguments.clear();
      break;
    }
    Arguments.push_back(V);
  }
 
  Type *RetTy = toVectorTy(Ctx.Types.inferScalarType(this), VF);
  SmallVector<Type *> ParamTys;
  for (unsigned I = 0; I != getNumOperands(); ++I)
    ParamTys.push_back(
        toVectorTy(Ctx.Types.inferScalarType(getOperand(I)), VF));
 
  // TODO: Rework TTI interface to avoid reliance on underlying IntrinsicInst.
  FastMathFlags FMF = hasFastMathFlags() ? getFastMathFlags() : FastMathFlags();
  IntrinsicCostAttributes CostAttrs(
      VectorIntrinsicID, RetTy, Arguments, ParamTys, FMF,
      dyn_cast_or_null<IntrinsicInst>(getUnderlyingValue()));
  return Ctx.TTI.getIntrinsicInstrCost(CostAttrs, CostKind);
}
 
StringRef VPWidenIntrinsicRecipe::getIntrinsicName() const {
  return Intrinsic::getBaseName(VectorIntrinsicID);
}
 
bool VPWidenIntrinsicRecipe::onlyFirstLaneUsed(const VPValue *Op) const {
  assert(is_contained(operands(), Op) && "Op must be an operand of the recipe");
  // Vector predication intrinsics only demand the the first lane the last
  // operand (the EVL operand).
  return VPIntrinsic::isVPIntrinsic(VectorIntrinsicID) &&
         Op == getOperand(getNumOperands() - 1);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPWidenIntrinsicRecipe::print(raw_ostream &O, const Twine &Indent,
                                   VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN-INTRINSIC ";
  if (ResultTy->isVoidTy()) {
    O << "void ";
  } else {
    printAsOperand(O, SlotTracker);
    O << " = ";
  }
 
  O << "call";
  printFlags(O);
  O << getIntrinsicName() << "(";
 
  interleaveComma(operands(), O, [&O, &SlotTracker](VPValue *Op) {
    Op->printAsOperand(O, SlotTracker);
  });
  O << ")";
}
#endif
 
void VPHistogramRecipe::execute(VPTransformState &State) {
  State.setDebugLocFrom(getDebugLoc());
  IRBuilderBase &Builder = State.Builder;
 
  Value *Address = State.get(getOperand(0));
  Value *IncAmt = State.get(getOperand(1), /*IsScalar=*/true);
  VectorType *VTy = cast<VectorType>(Address->getType());
 
  // The histogram intrinsic requires a mask even if the recipe doesn't;
  // if the mask operand was omitted then all lanes should be executed and
  // we just need to synthesize an all-true mask.
  Value *Mask = nullptr;
  if (VPValue *VPMask = getMask())
    Mask = State.get(VPMask);
  else
    Mask =
        Builder.CreateVectorSplat(VTy->getElementCount(), Builder.getInt1(1));
 
  // If this is a subtract, we want to invert the increment amount. We may
  // add a separate intrinsic in future, but for now we'll try this.
  if (Opcode == Instruction::Sub)
    IncAmt = Builder.CreateNeg(IncAmt);
  else
    assert(Opcode == Instruction::Add && "only add or sub supported for now");
 
  State.Builder.CreateIntrinsic(Intrinsic::experimental_vector_histogram_add,
                                {VTy, IncAmt->getType()},
                                {Address, IncAmt, Mask});
}
 
InstructionCost VPHistogramRecipe::computeCost(ElementCount VF,
                                               VPCostContext &Ctx) const {
  // FIXME: Take the gather and scatter into account as well. For now we're
  //        generating the same cost as the fallback path, but we'll likely
  //        need to create a new TTI method for determining the cost, including
  //        whether we can use base + vec-of-smaller-indices or just
  //        vec-of-pointers.
  assert(VF.isVector() && "Invalid VF for histogram cost");
  Type *AddressTy = Ctx.Types.inferScalarType(getOperand(0));
  VPValue *IncAmt = getOperand(1);
  Type *IncTy = Ctx.Types.inferScalarType(IncAmt);
  VectorType *VTy = VectorType::get(IncTy, VF);
 
  // Assume that a non-constant update value (or a constant != 1) requires
  // a multiply, and add that into the cost.
  InstructionCost MulCost =
      Ctx.TTI.getArithmeticInstrCost(Instruction::Mul, VTy);
  if (IncAmt->isLiveIn()) {
    ConstantInt *CI = dyn_cast<ConstantInt>(IncAmt->getLiveInIRValue());
 
    if (CI && CI->getZExtValue() == 1)
      MulCost = TTI::TCC_Free;
  }
 
  // Find the cost of the histogram operation itself.
  Type *PtrTy = VectorType::get(AddressTy, VF);
  Type *MaskTy = VectorType::get(Type::getInt1Ty(Ctx.LLVMCtx), VF);
  IntrinsicCostAttributes ICA(Intrinsic::experimental_vector_histogram_add,
                              Type::getVoidTy(Ctx.LLVMCtx),
                              {PtrTy, IncTy, MaskTy});
 
  // Add the costs together with the add/sub operation.
  return Ctx.TTI.getIntrinsicInstrCost(
             ICA, TargetTransformInfo::TCK_RecipThroughput) +
         MulCost + Ctx.TTI.getArithmeticInstrCost(Opcode, VTy);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPHistogramRecipe::print(raw_ostream &O, const Twine &Indent,
                              VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN-HISTOGRAM buckets: ";
  getOperand(0)->printAsOperand(O, SlotTracker);
 
  if (Opcode == Instruction::Sub)
    O << ", dec: ";
  else {
    assert(Opcode == Instruction::Add);
    O << ", inc: ";
  }
  getOperand(1)->printAsOperand(O, SlotTracker);
 
  if (VPValue *Mask = getMask()) {
    O << ", mask: ";
    Mask->printAsOperand(O, SlotTracker);
  }
}
 
void VPWidenSelectRecipe::print(raw_ostream &O, const Twine &Indent,
                                VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN-SELECT ";
  printAsOperand(O, SlotTracker);
  O << " = select ";
  getOperand(0)->printAsOperand(O, SlotTracker);
  O << ", ";
  getOperand(1)->printAsOperand(O, SlotTracker);
  O << ", ";
  getOperand(2)->printAsOperand(O, SlotTracker);
  O << (isInvariantCond() ? " (condition is loop invariant)" : "");
}
#endif
 
void VPWidenSelectRecipe::execute(VPTransformState &State) {
  State.setDebugLocFrom(getDebugLoc());
 
  // The condition can be loop invariant but still defined inside the
  // loop. This means that we can't just use the original 'cond' value.
  // We have to take the 'vectorized' value and pick the first lane.
  // Instcombine will make this a no-op.
  auto *InvarCond =
      isInvariantCond() ? State.get(getCond(), VPLane(0)) : nullptr;
 
  Value *Cond = InvarCond ? InvarCond : State.get(getCond());
  Value *Op0 = State.get(getOperand(1));
  Value *Op1 = State.get(getOperand(2));
  Value *Sel = State.Builder.CreateSelect(Cond, Op0, Op1);
  State.set(this, Sel);
  State.addMetadata(Sel, dyn_cast_or_null<Instruction>(getUnderlyingValue()));
}
 
InstructionCost VPWidenSelectRecipe::computeCost(ElementCount VF,
                                                 VPCostContext &Ctx) const {
  SelectInst *SI = cast<SelectInst>(getUnderlyingValue());
  bool ScalarCond = getOperand(0)->isDefinedOutsideLoopRegions();
  Type *ScalarTy = Ctx.Types.inferScalarType(this);
  Type *VectorTy = toVectorTy(Ctx.Types.inferScalarType(this), VF);
  TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
 
  VPValue *Op0, *Op1;
  using namespace llvm::VPlanPatternMatch;
  if (!ScalarCond && ScalarTy->getScalarSizeInBits() == 1 &&
      (match(this, m_LogicalAnd(m_VPValue(Op0), m_VPValue(Op1))) ||
       match(this, m_LogicalOr(m_VPValue(Op0), m_VPValue(Op1))))) {
    // select x, y, false --> x & y
    // select x, true, y --> x | y
    const auto [Op1VK, Op1VP] = Ctx.getOperandInfo(Op0);
    const auto [Op2VK, Op2VP] = Ctx.getOperandInfo(Op1);
 
    SmallVector<const Value *, 2> Operands;
    if (all_of(operands(),
               [](VPValue *Op) { return Op->getUnderlyingValue(); }))
      Operands.append(SI->op_begin(), SI->op_end());
    bool IsLogicalOr = match(this, m_LogicalOr(m_VPValue(Op0), m_VPValue(Op1)));
    return Ctx.TTI.getArithmeticInstrCost(
        IsLogicalOr ? Instruction::Or : Instruction::And, VectorTy, CostKind,
        {Op1VK, Op1VP}, {Op2VK, Op2VP}, Operands, SI);
  }
 
  Type *CondTy = Ctx.Types.inferScalarType(getOperand(0));
  if (!ScalarCond)
    CondTy = VectorType::get(CondTy, VF);
 
  CmpInst::Predicate Pred = CmpInst::BAD_ICMP_PREDICATE;
  if (auto *Cmp = dyn_cast<CmpInst>(SI->getCondition()))
    Pred = Cmp->getPredicate();
  return Ctx.TTI.getCmpSelInstrCost(Instruction::Select, VectorTy, CondTy, Pred,
                                    CostKind, {TTI::OK_AnyValue, TTI::OP_None},
                                    {TTI::OK_AnyValue, TTI::OP_None}, SI);
}
 
VPRecipeWithIRFlags::FastMathFlagsTy::FastMathFlagsTy(
    const FastMathFlags &FMF) {
  AllowReassoc = FMF.allowReassoc();
  NoNaNs = FMF.noNaNs();
  NoInfs = FMF.noInfs();
  NoSignedZeros = FMF.noSignedZeros();
  AllowReciprocal = FMF.allowReciprocal();
  AllowContract = FMF.allowContract();
  ApproxFunc = FMF.approxFunc();
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPRecipeWithIRFlags::printFlags(raw_ostream &O) const {
  switch (OpType) {
  case OperationType::Cmp:
    O << " " << CmpInst::getPredicateName(getPredicate());
    break;
  case OperationType::DisjointOp:
    if (DisjointFlags.IsDisjoint)
      O << " disjoint";
    break;
  case OperationType::PossiblyExactOp:
    if (ExactFlags.IsExact)
      O << " exact";
    break;
  case OperationType::OverflowingBinOp:
    if (WrapFlags.HasNUW)
      O << " nuw";
    if (WrapFlags.HasNSW)
      O << " nsw";
    break;
  case OperationType::FPMathOp:
    getFastMathFlags().print(O);
    break;
  case OperationType::GEPOp:
    if (GEPFlags.isInBounds())
      O << " inbounds";
    else if (GEPFlags.hasNoUnsignedSignedWrap())
      O << " nusw";
    if (GEPFlags.hasNoUnsignedWrap())
      O << " nuw";
    break;
  case OperationType::NonNegOp:
    if (NonNegFlags.NonNeg)
      O << " nneg";
    break;
  case OperationType::Other:
    break;
  }
  if (getNumOperands() > 0)
    O << " ";
}
#endif
 
void VPWidenRecipe::execute(VPTransformState &State) {
  State.setDebugLocFrom(getDebugLoc());
  auto &Builder = State.Builder;
  switch (Opcode) {
  case Instruction::Call:
  case Instruction::Br:
  case Instruction::PHI:
  case Instruction::GetElementPtr:
  case Instruction::Select:
    llvm_unreachable("This instruction is handled by a different recipe.");
  case Instruction::UDiv:
  case Instruction::SDiv:
  case Instruction::SRem:
  case Instruction::URem:
  case Instruction::Add:
  case Instruction::FAdd:
  case Instruction::Sub:
  case Instruction::FSub:
  case Instruction::FNeg:
  case Instruction::Mul:
  case Instruction::FMul:
  case Instruction::FDiv:
  case Instruction::FRem:
  case Instruction::Shl:
  case Instruction::LShr:
  case Instruction::AShr:
  case Instruction::And:
  case Instruction::Or:
  case Instruction::Xor: {
    // Just widen unops and binops.
    SmallVector<Value *, 2> Ops;
    for (VPValue *VPOp : operands())
      Ops.push_back(State.get(VPOp));
 
    Value *V = Builder.CreateNAryOp(Opcode, Ops);
 
    if (auto *VecOp = dyn_cast<Instruction>(V))
      setFlags(VecOp);
 
    // Use this vector value for all users of the original instruction.
    State.set(this, V);
    State.addMetadata(V, dyn_cast_or_null<Instruction>(getUnderlyingValue()));
    break;
  }
  case Instruction::Freeze: {
    Value *Op = State.get(getOperand(0));
 
    Value *Freeze = Builder.CreateFreeze(Op);
    State.set(this, Freeze);
    break;
  }
  case Instruction::ICmp:
  case Instruction::FCmp: {
    // Widen compares. Generate vector compares.
    bool FCmp = Opcode == Instruction::FCmp;
    Value *A = State.get(getOperand(0));
    Value *B = State.get(getOperand(1));
    Value *C = nullptr;
    if (FCmp) {
      // Propagate fast math flags.
      C = Builder.CreateFCmpFMF(
          getPredicate(), A, B,
          dyn_cast_or_null<Instruction>(getUnderlyingValue()));
    } else {
      C = Builder.CreateICmp(getPredicate(), A, B);
    }
    State.set(this, C);
    State.addMetadata(C, dyn_cast_or_null<Instruction>(getUnderlyingValue()));
    break;
  }
  default:
    // This instruction is not vectorized by simple widening.
    LLVM_DEBUG(dbgs() << "LV: Found an unhandled opcode : "
                      << Instruction::getOpcodeName(Opcode));
    llvm_unreachable("Unhandled instruction!");
  } // end of switch.
 
#if !defined(NDEBUG)
  // Verify that VPlan type inference results agree with the type of the
  // generated values.
  assert(VectorType::get(State.TypeAnalysis.inferScalarType(this), State.VF) ==
             State.get(this)->getType() &&
         "inferred type and type from generated instructions do not match");
#endif
}
 
InstructionCost VPWidenRecipe::computeCost(ElementCount VF,
                                           VPCostContext &Ctx) const {
  TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
  switch (Opcode) {
  case Instruction::FNeg: {
    Type *VectorTy = toVectorTy(Ctx.Types.inferScalarType(this), VF);
    return Ctx.TTI.getArithmeticInstrCost(
        Opcode, VectorTy, CostKind,
        {TargetTransformInfo::OK_AnyValue, TargetTransformInfo::OP_None},
        {TargetTransformInfo::OK_AnyValue, TargetTransformInfo::OP_None});
  }
 
  case Instruction::UDiv:
  case Instruction::SDiv:
  case Instruction::SRem:
  case Instruction::URem:
    // More complex computation, let the legacy cost-model handle this for now.
    return Ctx.getLegacyCost(cast<Instruction>(getUnderlyingValue()), VF);
  case Instruction::Add:
  case Instruction::FAdd:
  case Instruction::Sub:
  case Instruction::FSub:
  case Instruction::Mul:
  case Instruction::FMul:
  case Instruction::FDiv:
  case Instruction::FRem:
  case Instruction::Shl:
  case Instruction::LShr:
  case Instruction::AShr:
  case Instruction::And:
  case Instruction::Or:
  case Instruction::Xor: {
    VPValue *RHS = getOperand(1);
    // Certain instructions can be cheaper to vectorize if they have a constant
    // second vector operand. One example of this are shifts on x86.
    TargetTransformInfo::OperandValueInfo RHSInfo = {
        TargetTransformInfo::OK_AnyValue, TargetTransformInfo::OP_None};
    if (RHS->isLiveIn())
      RHSInfo = Ctx.TTI.getOperandInfo(RHS->getLiveInIRValue());
 
    if (RHSInfo.Kind == TargetTransformInfo::OK_AnyValue &&
        getOperand(1)->isDefinedOutsideLoopRegions())
      RHSInfo.Kind = TargetTransformInfo::OK_UniformValue;
    Type *VectorTy = toVectorTy(Ctx.Types.inferScalarType(this), VF);
    Instruction *CtxI = dyn_cast_or_null<Instruction>(getUnderlyingValue());
 
    SmallVector<const Value *, 4> Operands;
    if (CtxI)
      Operands.append(CtxI->value_op_begin(), CtxI->value_op_end());
    return Ctx.TTI.getArithmeticInstrCost(
        Opcode, VectorTy, CostKind,
        {TargetTransformInfo::OK_AnyValue, TargetTransformInfo::OP_None},
        RHSInfo, Operands, CtxI, &Ctx.TLI);
  }
  case Instruction::Freeze: {
    // This opcode is unknown. Assume that it is the same as 'mul'.
    Type *VectorTy = toVectorTy(Ctx.Types.inferScalarType(this), VF);
    return Ctx.TTI.getArithmeticInstrCost(Instruction::Mul, VectorTy, CostKind);
  }
  case Instruction::ICmp:
  case Instruction::FCmp: {
    Instruction *CtxI = dyn_cast_or_null<Instruction>(getUnderlyingValue());
    Type *VectorTy = toVectorTy(Ctx.Types.inferScalarType(getOperand(0)), VF);
    return Ctx.TTI.getCmpSelInstrCost(Opcode, VectorTy, nullptr, getPredicate(),
                                      CostKind,
                                      {TTI::OK_AnyValue, TTI::OP_None},
                                      {TTI::OK_AnyValue, TTI::OP_None}, CtxI);
  }
  default:
    llvm_unreachable("Unsupported opcode for instruction");
  }
}
 
void VPWidenEVLRecipe::execute(VPTransformState &State) {
  unsigned Opcode = getOpcode();
  // TODO: Support other opcodes
  if (!Instruction::isBinaryOp(Opcode) && !Instruction::isUnaryOp(Opcode))
    llvm_unreachable("Unsupported opcode in VPWidenEVLRecipe::execute");
 
  State.setDebugLocFrom(getDebugLoc());
 
  assert(State.get(getOperand(0))->getType()->isVectorTy() &&
         "VPWidenEVLRecipe should not be used for scalars");
 
  VPValue *EVL = getEVL();
  Value *EVLArg = State.get(EVL, /*NeedsScalar=*/true);
  IRBuilderBase &BuilderIR = State.Builder;
  VectorBuilder Builder(BuilderIR);
  Value *Mask = BuilderIR.CreateVectorSplat(State.VF, BuilderIR.getTrue());
 
  SmallVector<Value *, 4> Ops;
  for (unsigned I = 0, E = getNumOperands() - 1; I < E; ++I) {
    VPValue *VPOp = getOperand(I);
    Ops.push_back(State.get(VPOp));
  }
 
  Builder.setMask(Mask).setEVL(EVLArg);
  Value *VPInst =
      Builder.createVectorInstruction(Opcode, Ops[0]->getType(), Ops, "vp.op");
  // Currently vp-intrinsics only accept FMF flags.
  // TODO: Enable other flags when support is added.
  if (isa<FPMathOperator>(VPInst))
    setFlags(cast<Instruction>(VPInst));
 
  State.set(this, VPInst);
  State.addMetadata(VPInst,
                    dyn_cast_or_null<Instruction>(getUnderlyingValue()));
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPWidenRecipe::print(raw_ostream &O, const Twine &Indent,
                          VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN ";
  printAsOperand(O, SlotTracker);
  O << " = " << Instruction::getOpcodeName(Opcode);
  printFlags(O);
  printOperands(O, SlotTracker);
}
 
void VPWidenEVLRecipe::print(raw_ostream &O, const Twine &Indent,
                             VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN ";
  printAsOperand(O, SlotTracker);
  O << " = vp." << Instruction::getOpcodeName(getOpcode());
  printFlags(O);
  printOperands(O, SlotTracker);
}
#endif
 
void VPWidenCastRecipe::execute(VPTransformState &State) {
  State.setDebugLocFrom(getDebugLoc());
  auto &Builder = State.Builder;
  /// Vectorize casts.
  assert(State.VF.isVector() && "Not vectorizing?");
  Type *DestTy = VectorType::get(getResultType(), State.VF);
  VPValue *Op = getOperand(0);
  Value *A = State.get(Op);
  Value *Cast = Builder.CreateCast(Instruction::CastOps(Opcode), A, DestTy);
  State.set(this, Cast);
  State.addMetadata(Cast, cast_or_null<Instruction>(getUnderlyingValue()));
  if (auto *CastOp = dyn_cast<Instruction>(Cast))
    setFlags(CastOp);
}
 
InstructionCost VPWidenCastRecipe::computeCost(ElementCount VF,
                                               VPCostContext &Ctx) const {
  // TODO: In some cases, VPWidenCastRecipes are created but not considered in
  // the legacy cost model, including truncates/extends when evaluating a
  // reduction in a smaller type.
  if (!getUnderlyingValue())
    return 0;
  // Computes the CastContextHint from a recipes that may access memory.
  auto ComputeCCH = [&](const VPRecipeBase *R) -> TTI::CastContextHint {
    if (VF.isScalar())
      return TTI::CastContextHint::Normal;
    if (isa<VPInterleaveRecipe>(R))
      return TTI::CastContextHint::Interleave;
    if (const auto *ReplicateRecipe = dyn_cast<VPReplicateRecipe>(R))
      return ReplicateRecipe->isPredicated() ? TTI::CastContextHint::Masked
                                             : TTI::CastContextHint::Normal;
    const auto *WidenMemoryRecipe = dyn_cast<VPWidenMemoryRecipe>(R);
    if (WidenMemoryRecipe == nullptr)
      return TTI::CastContextHint::None;
    if (!WidenMemoryRecipe->isConsecutive())
      return TTI::CastContextHint::GatherScatter;
    if (WidenMemoryRecipe->isReverse())
      return TTI::CastContextHint::Reversed;
    if (WidenMemoryRecipe->isMasked())
      return TTI::CastContextHint::Masked;
    return TTI::CastContextHint::Normal;
  };
 
  VPValue *Operand = getOperand(0);
  TTI::CastContextHint CCH = TTI::CastContextHint::None;
  // For Trunc/FPTrunc, get the context from the only user.
  if ((Opcode == Instruction::Trunc || Opcode == Instruction::FPTrunc) &&
      !hasMoreThanOneUniqueUser() && getNumUsers() > 0) {
    if (auto *StoreRecipe = dyn_cast<VPRecipeBase>(*user_begin()))
      CCH = ComputeCCH(StoreRecipe);
  }
  // For Z/Sext, get the context from the operand.
  else if (Opcode == Instruction::ZExt || Opcode == Instruction::SExt ||
           Opcode == Instruction::FPExt) {
    if (Operand->isLiveIn())
      CCH = TTI::CastContextHint::Normal;
    else if (Operand->getDefiningRecipe())
      CCH = ComputeCCH(Operand->getDefiningRecipe());
  }
 
  auto *SrcTy =
      cast<VectorType>(toVectorTy(Ctx.Types.inferScalarType(Operand), VF));
  auto *DestTy = cast<VectorType>(toVectorTy(getResultType(), VF));
  // Arm TTI will use the underlying instruction to determine the cost.
  return Ctx.TTI.getCastInstrCost(
      Opcode, DestTy, SrcTy, CCH, TTI::TCK_RecipThroughput,
      dyn_cast_if_present<Instruction>(getUnderlyingValue()));
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPWidenCastRecipe::print(raw_ostream &O, const Twine &Indent,
                              VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN-CAST ";
  printAsOperand(O, SlotTracker);
  O << " = " << Instruction::getOpcodeName(Opcode);
  printFlags(O);
  printOperands(O, SlotTracker);
  O << " to " << *getResultType();
}
#endif
 
InstructionCost VPHeaderPHIRecipe::computeCost(ElementCount VF,
                                               VPCostContext &Ctx) const {
  return Ctx.TTI.getCFInstrCost(Instruction::PHI, TTI::TCK_RecipThroughput);
}
 
/// This function adds
/// (0 * Step, 1 * Step, 2 * Step, ...)
/// to each vector element of Val.
/// \p Opcode is relevant for FP induction variable.
static Value *getStepVector(Value *Val, Value *Step,
                            Instruction::BinaryOps BinOp, ElementCount VF,
                            IRBuilderBase &Builder) {
  assert(VF.isVector() && "only vector VFs are supported");
 
  // Create and check the types.
  auto *ValVTy = cast<VectorType>(Val->getType());
  ElementCount VLen = ValVTy->getElementCount();
 
  Type *STy = Val->getType()->getScalarType();
  assert((STy->isIntegerTy() || STy->isFloatingPointTy()) &&
         "Induction Step must be an integer or FP");
  assert(Step->getType() == STy && "Step has wrong type");
 
  SmallVector<Constant *, 8> Indices;
 
  // Create a vector of consecutive numbers from zero to VF.
  VectorType *InitVecValVTy = ValVTy;
  if (STy->isFloatingPointTy()) {
    Type *InitVecValSTy =
        IntegerType::get(STy->getContext(), STy->getScalarSizeInBits());
    InitVecValVTy = VectorType::get(InitVecValSTy, VLen);
  }
  Value *InitVec = Builder.CreateStepVector(InitVecValVTy);
 
  if (STy->isIntegerTy()) {
    Step = Builder.CreateVectorSplat(VLen, Step);
    assert(Step->getType() == Val->getType() && "Invalid step vec");
    // FIXME: The newly created binary instructions should contain nsw/nuw
    // flags, which can be found from the original scalar operations.
    Step = Builder.CreateMul(InitVec, Step);
    return Builder.CreateAdd(Val, Step, "induction");
  }
 
  // Floating point induction.
  assert((BinOp == Instruction::FAdd || BinOp == Instruction::FSub) &&
         "Binary Opcode should be specified for FP induction");
  InitVec = Builder.CreateUIToFP(InitVec, ValVTy);
 
  Step = Builder.CreateVectorSplat(VLen, Step);
  Value *MulOp = Builder.CreateFMul(InitVec, Step);
  return Builder.CreateBinOp(BinOp, Val, MulOp, "induction");
}
 
/// A helper function that returns an integer or floating-point constant with
/// value C.
static Constant *getSignedIntOrFpConstant(Type *Ty, int64_t C) {
  return Ty->isIntegerTy() ? ConstantInt::getSigned(Ty, C)
                           : ConstantFP::get(Ty, C);
}
 
void VPWidenIntOrFpInductionRecipe::execute(VPTransformState &State) {
  assert(!State.Lane && "Int or FP induction being replicated.");
 
  Value *Start = getStartValue()->getLiveInIRValue();
  const InductionDescriptor &ID = getInductionDescriptor();
  TruncInst *Trunc = getTruncInst();
  IRBuilderBase &Builder = State.Builder;
  assert(getPHINode()->getType() == ID.getStartValue()->getType() &&
         "Types must match");
  assert(State.VF.isVector() && "must have vector VF");
 
  // The value from the original loop to which we are mapping the new induction
  // variable.
  Instruction *EntryVal = Trunc ? cast<Instruction>(Trunc) : getPHINode();
 
  // Fast-math-flags propagate from the original induction instruction.
  IRBuilder<>::FastMathFlagGuard FMFG(Builder);
  if (ID.getInductionBinOp() && isa<FPMathOperator>(ID.getInductionBinOp()))
    Builder.setFastMathFlags(ID.getInductionBinOp()->getFastMathFlags());
 
  // Now do the actual transformations, and start with fetching the step value.
  Value *Step = State.get(getStepValue(), VPLane(0));
 
  assert((isa<PHINode>(EntryVal) || isa<TruncInst>(EntryVal)) &&
         "Expected either an induction phi-node or a truncate of it!");
 
  // Construct the initial value of the vector IV in the vector loop preheader
  auto CurrIP = Builder.saveIP();
  BasicBlock *VectorPH = State.CFG.getPreheaderBBFor(this);
  Builder.SetInsertPoint(VectorPH->getTerminator());
  if (isa<TruncInst>(EntryVal)) {
    assert(Start->getType()->isIntegerTy() &&
           "Truncation requires an integer type");
    auto *TruncType = cast<IntegerType>(EntryVal->getType());
    Step = Builder.CreateTrunc(Step, TruncType);
    Start = Builder.CreateCast(Instruction::Trunc, Start, TruncType);
  }
 
  Value *SplatStart = Builder.CreateVectorSplat(State.VF, Start);
  Value *SteppedStart = getStepVector(SplatStart, Step, ID.getInductionOpcode(),
                                      State.VF, State.Builder);
 
  // We create vector phi nodes for both integer and floating-point induction
  // variables. Here, we determine the kind of arithmetic we will perform.
  Instruction::BinaryOps AddOp;
  Instruction::BinaryOps MulOp;
  if (Step->getType()->isIntegerTy()) {
    AddOp = Instruction::Add;
    MulOp = Instruction::Mul;
  } else {
    AddOp = ID.getInductionOpcode();
    MulOp = Instruction::FMul;
  }
 
  Value *SplatVF;
  if (VPValue *SplatVFOperand = getSplatVFValue()) {
    // The recipe has been unrolled. In that case, fetch the splat value for the
    // induction increment.
    SplatVF = State.get(SplatVFOperand);
  } else {
    // Multiply the vectorization factor by the step using integer or
    // floating-point arithmetic as appropriate.
    Type *StepType = Step->getType();
    Value *RuntimeVF = State.get(getVFValue(), VPLane(0));
    if (Step->getType()->isFloatingPointTy())
      RuntimeVF = Builder.CreateUIToFP(RuntimeVF, StepType);
    else
      RuntimeVF = Builder.CreateZExtOrTrunc(RuntimeVF, StepType);
    Value *Mul = Builder.CreateBinOp(MulOp, Step, RuntimeVF);
 
    // Create a vector splat to use in the induction update.
    SplatVF = Builder.CreateVectorSplat(State.VF, Mul);
  }
 
  Builder.restoreIP(CurrIP);
 
  // We may need to add the step a number of times, depending on the unroll
  // factor. The last of those goes into the PHI.
  PHINode *VecInd = PHINode::Create(SteppedStart->getType(), 2, "vec.ind");
  VecInd->insertBefore(State.CFG.PrevBB->getFirstInsertionPt());
  VecInd->setDebugLoc(getDebugLoc());
  State.set(this, VecInd);
 
  Instruction *LastInduction = cast<Instruction>(
      Builder.CreateBinOp(AddOp, VecInd, SplatVF, "vec.ind.next"));
  if (isa<TruncInst>(EntryVal))
    State.addMetadata(LastInduction, EntryVal);
  LastInduction->setDebugLoc(getDebugLoc());
 
  VecInd->addIncoming(SteppedStart, VectorPH);
  // Add induction update using an incorrect block temporarily. The phi node
  // will be fixed after VPlan execution. Note that at this point the latch
  // block cannot be used, as it does not exist yet.
  // TODO: Model increment value in VPlan, by turning the recipe into a
  // multi-def and a subclass of VPHeaderPHIRecipe.
  VecInd->addIncoming(LastInduction, VectorPH);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPWidenIntOrFpInductionRecipe::print(raw_ostream &O, const Twine &Indent,
                                          VPSlotTracker &SlotTracker) const {
  O << Indent;
  printAsOperand(O, SlotTracker);
  O << " = WIDEN-INDUCTION  ";
  printOperands(O, SlotTracker);
 
  if (auto *TI = getTruncInst())
    O << " (truncated to " << *TI->getType() << ")";
}
#endif
 
bool VPWidenIntOrFpInductionRecipe::isCanonical() const {
  // The step may be defined by a recipe in the preheader (e.g. if it requires
  // SCEV expansion), but for the canonical induction the step is required to be
  // 1, which is represented as live-in.
  if (getStepValue()->getDefiningRecipe())
    return false;
  auto *StepC = dyn_cast<ConstantInt>(getStepValue()->getLiveInIRValue());
  auto *StartC = dyn_cast<ConstantInt>(getStartValue()->getLiveInIRValue());
  auto *CanIV = cast<VPCanonicalIVPHIRecipe>(&*getParent()->begin());
  return StartC && StartC->isZero() && StepC && StepC->isOne() &&
         getScalarType() == CanIV->getScalarType();
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPDerivedIVRecipe::print(raw_ostream &O, const Twine &Indent,
                              VPSlotTracker &SlotTracker) const {
  O << Indent;
  printAsOperand(O, SlotTracker);
  O << " = DERIVED-IV ";
  getStartValue()->printAsOperand(O, SlotTracker);
  O << " + ";
  getOperand(1)->printAsOperand(O, SlotTracker);
  O << " * ";
  getStepValue()->printAsOperand(O, SlotTracker);
}
#endif
 
void VPScalarIVStepsRecipe::execute(VPTransformState &State) {
  // Fast-math-flags propagate from the original induction instruction.
  IRBuilder<>::FastMathFlagGuard FMFG(State.Builder);
  if (hasFastMathFlags())
    State.Builder.setFastMathFlags(getFastMathFlags());
 
  /// Compute scalar induction steps. \p ScalarIV is the scalar induction
  /// variable on which to base the steps, \p Step is the size of the step.
 
  Value *BaseIV = State.get(getOperand(0), VPLane(0));
  Value *Step = State.get(getStepValue(), VPLane(0));
  IRBuilderBase &Builder = State.Builder;
 
  // Ensure step has the same type as that of scalar IV.
  Type *BaseIVTy = BaseIV->getType()->getScalarType();
  assert(BaseIVTy == Step->getType() && "Types of BaseIV and Step must match!");
 
  // We build scalar steps for both integer and floating-point induction
  // variables. Here, we determine the kind of arithmetic we will perform.
  Instruction::BinaryOps AddOp;
  Instruction::BinaryOps MulOp;
  if (BaseIVTy->isIntegerTy()) {
    AddOp = Instruction::Add;
    MulOp = Instruction::Mul;
  } else {
    AddOp = InductionOpcode;
    MulOp = Instruction::FMul;
  }
 
  // Determine the number of scalars we need to generate for each unroll
  // iteration.
  bool FirstLaneOnly = vputils::onlyFirstLaneUsed(this);
  // Compute the scalar steps and save the results in State.
  Type *IntStepTy =
      IntegerType::get(BaseIVTy->getContext(), BaseIVTy->getScalarSizeInBits());
  Type *VecIVTy = nullptr;
  Value *UnitStepVec = nullptr, *SplatStep = nullptr, *SplatIV = nullptr;
  if (!FirstLaneOnly && State.VF.isScalable()) {
    VecIVTy = VectorType::get(BaseIVTy, State.VF);
    UnitStepVec =
        Builder.CreateStepVector(VectorType::get(IntStepTy, State.VF));
    SplatStep = Builder.CreateVectorSplat(State.VF, Step);
    SplatIV = Builder.CreateVectorSplat(State.VF, BaseIV);
  }
 
  unsigned StartLane = 0;
  unsigned EndLane = FirstLaneOnly ? 1 : State.VF.getKnownMinValue();
  if (State.Lane) {
    StartLane = State.Lane->getKnownLane();
    EndLane = StartLane + 1;
  }
  Value *StartIdx0 =
      createStepForVF(Builder, IntStepTy, State.VF, getUnrollPart(*this));
 
  if (!FirstLaneOnly && State.VF.isScalable()) {
    auto *SplatStartIdx = Builder.CreateVectorSplat(State.VF, StartIdx0);
    auto *InitVec = Builder.CreateAdd(SplatStartIdx, UnitStepVec);
    if (BaseIVTy->isFloatingPointTy())
      InitVec = Builder.CreateSIToFP(InitVec, VecIVTy);
    auto *Mul = Builder.CreateBinOp(MulOp, InitVec, SplatStep);
    auto *Add = Builder.CreateBinOp(AddOp, SplatIV, Mul);
    State.set(this, Add);
    // It's useful to record the lane values too for the known minimum number
    // of elements so we do those below. This improves the code quality when
    // trying to extract the first element, for example.
  }
 
  if (BaseIVTy->isFloatingPointTy())
    StartIdx0 = Builder.CreateSIToFP(StartIdx0, BaseIVTy);
 
  for (unsigned Lane = StartLane; Lane < EndLane; ++Lane) {
    Value *StartIdx = Builder.CreateBinOp(
        AddOp, StartIdx0, getSignedIntOrFpConstant(BaseIVTy, Lane));
    // The step returned by `createStepForVF` is a runtime-evaluated value
    // when VF is scalable. Otherwise, it should be folded into a Constant.
    assert((State.VF.isScalable() || isa<Constant>(StartIdx)) &&
           "Expected StartIdx to be folded to a constant when VF is not "
           "scalable");
    auto *Mul = Builder.CreateBinOp(MulOp, StartIdx, Step);
    auto *Add = Builder.CreateBinOp(AddOp, BaseIV, Mul);
    State.set(this, Add, VPLane(Lane));
  }
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPScalarIVStepsRecipe::print(raw_ostream &O, const Twine &Indent,
                                  VPSlotTracker &SlotTracker) const {
  O << Indent;
  printAsOperand(O, SlotTracker);
  O << " = SCALAR-STEPS ";
  printOperands(O, SlotTracker);
}
#endif
 
void VPWidenGEPRecipe::execute(VPTransformState &State) {
  assert(State.VF.isVector() && "not widening");
  auto *GEP = cast<GetElementPtrInst>(getUnderlyingInstr());
  // Construct a vector GEP by widening the operands of the scalar GEP as
  // necessary. We mark the vector GEP 'inbounds' if appropriate. A GEP
  // results in a vector of pointers when at least one operand of the GEP
  // is vector-typed. Thus, to keep the representation compact, we only use
  // vector-typed operands for loop-varying values.
 
  if (areAllOperandsInvariant()) {
    // If we are vectorizing, but the GEP has only loop-invariant operands,
    // the GEP we build (by only using vector-typed operands for
    // loop-varying values) would be a scalar pointer. Thus, to ensure we
    // produce a vector of pointers, we need to either arbitrarily pick an
    // operand to broadcast, or broadcast a clone of the original GEP.
    // Here, we broadcast a clone of the original.
    //
    // TODO: If at some point we decide to scalarize instructions having
    //       loop-invariant operands, this special case will no longer be
    //       required. We would add the scalarization decision to
    //       collectLoopScalars() and teach getVectorValue() to broadcast
    //       the lane-zero scalar value.
    SmallVector<Value *> Ops;
    for (unsigned I = 0, E = getNumOperands(); I != E; I++)
      Ops.push_back(State.get(getOperand(I), VPLane(0)));
 
    auto *NewGEP = State.Builder.CreateGEP(GEP->getSourceElementType(), Ops[0],
                                           ArrayRef(Ops).drop_front(), "",
                                           getGEPNoWrapFlags());
    Value *Splat = State.Builder.CreateVectorSplat(State.VF, NewGEP);
    State.set(this, Splat);
    State.addMetadata(Splat, GEP);
  } else {
    // If the GEP has at least one loop-varying operand, we are sure to
    // produce a vector of pointers unless VF is scalar.
    // The pointer operand of the new GEP. If it's loop-invariant, we
    // won't broadcast it.
    auto *Ptr = isPointerLoopInvariant() ? State.get(getOperand(0), VPLane(0))
                                         : State.get(getOperand(0));
 
    // Collect all the indices for the new GEP. If any index is
    // loop-invariant, we won't broadcast it.
    SmallVector<Value *, 4> Indices;
    for (unsigned I = 1, E = getNumOperands(); I < E; I++) {
      VPValue *Operand = getOperand(I);
      if (isIndexLoopInvariant(I - 1))
        Indices.push_back(State.get(Operand, VPLane(0)));
      else
        Indices.push_back(State.get(Operand));
    }
 
    // Create the new GEP. Note that this GEP may be a scalar if VF == 1,
    // but it should be a vector, otherwise.
    auto *NewGEP = State.Builder.CreateGEP(GEP->getSourceElementType(), Ptr,
                                           Indices, "", getGEPNoWrapFlags());
    assert((State.VF.isScalar() || NewGEP->getType()->isVectorTy()) &&
           "NewGEP is not a pointer vector");
    State.set(this, NewGEP);
    State.addMetadata(NewGEP, GEP);
  }
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPWidenGEPRecipe::print(raw_ostream &O, const Twine &Indent,
                             VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN-GEP ";
  O << (isPointerLoopInvariant() ? "Inv" : "Var");
  for (size_t I = 0; I < getNumOperands() - 1; ++I)
    O << "[" << (isIndexLoopInvariant(I) ? "Inv" : "Var") << "]";
 
  O << " ";
  printAsOperand(O, SlotTracker);
  O << " = getelementptr";
  printFlags(O);
  printOperands(O, SlotTracker);
}
#endif
 
static Type *getGEPIndexTy(bool IsScalable, bool IsReverse,
                           unsigned CurrentPart, IRBuilderBase &Builder) {
  // Use i32 for the gep index type when the value is constant,
  // or query DataLayout for a more suitable index type otherwise.
  const DataLayout &DL = Builder.GetInsertBlock()->getDataLayout();
  return IsScalable && (IsReverse || CurrentPart > 0)
             ? DL.getIndexType(Builder.getPtrTy(0))
             : Builder.getInt32Ty();
}
 
void VPReverseVectorPointerRecipe::execute(VPTransformState &State) {
  auto &Builder = State.Builder;
  State.setDebugLocFrom(getDebugLoc());
  unsigned CurrentPart = getUnrollPart(*this);
  Type *IndexTy = getGEPIndexTy(State.VF.isScalable(), /*IsReverse*/ true,
                                CurrentPart, Builder);
 
  // The wide store needs to start at the last vector element.
  Value *RunTimeVF = State.get(getVFValue(), VPLane(0));
  if (IndexTy != RunTimeVF->getType())
    RunTimeVF = Builder.CreateZExtOrTrunc(RunTimeVF, IndexTy);
  // NumElt = -CurrentPart * RunTimeVF
  Value *NumElt = Builder.CreateMul(
      ConstantInt::get(IndexTy, -(int64_t)CurrentPart), RunTimeVF);
  // LastLane = 1 - RunTimeVF
  Value *LastLane = Builder.CreateSub(ConstantInt::get(IndexTy, 1), RunTimeVF);
  Value *Ptr = State.get(getOperand(0), VPLane(0));
  Value *ResultPtr =
      Builder.CreateGEP(IndexedTy, Ptr, NumElt, "", getGEPNoWrapFlags());
  ResultPtr = Builder.CreateGEP(IndexedTy, ResultPtr, LastLane, "",
                                getGEPNoWrapFlags());
 
  State.set(this, ResultPtr, /*IsScalar*/ true);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPReverseVectorPointerRecipe::print(raw_ostream &O, const Twine &Indent,
                                         VPSlotTracker &SlotTracker) const {
  O << Indent;
  printAsOperand(O, SlotTracker);
  O << " = reverse-vector-pointer";
  printFlags(O);
  printOperands(O, SlotTracker);
}
#endif
 
void VPVectorPointerRecipe::execute(VPTransformState &State) {
  auto &Builder = State.Builder;
  State.setDebugLocFrom(getDebugLoc());
  unsigned CurrentPart = getUnrollPart(*this);
  Type *IndexTy = getGEPIndexTy(State.VF.isScalable(), /*IsReverse*/ false,
                                CurrentPart, Builder);
  Value *Ptr = State.get(getOperand(0), VPLane(0));
 
  Value *Increment = createStepForVF(Builder, IndexTy, State.VF, CurrentPart);
  Value *ResultPtr =
      Builder.CreateGEP(IndexedTy, Ptr, Increment, "", getGEPNoWrapFlags());
 
  State.set(this, ResultPtr, /*IsScalar*/ true);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPVectorPointerRecipe::print(raw_ostream &O, const Twine &Indent,
                                  VPSlotTracker &SlotTracker) const {
  O << Indent;
  printAsOperand(O, SlotTracker);
  O << " = vector-pointer ";
 
  printOperands(O, SlotTracker);
}
#endif
 
void VPBlendRecipe::execute(VPTransformState &State) {
  assert(isNormalized() && "Expected blend to be normalized!");
  State.setDebugLocFrom(getDebugLoc());
  // We know that all PHIs in non-header blocks are converted into
  // selects, so we don't have to worry about the insertion order and we
  // can just use the builder.
  // At this point we generate the predication tree. There may be
  // duplications since this is a simple recursive scan, but future
  // optimizations will clean it up.
 
  unsigned NumIncoming = getNumIncomingValues();
 
  // Generate a sequence of selects of the form:
  // SELECT(Mask3, In3,
  //        SELECT(Mask2, In2,
  //               SELECT(Mask1, In1,
  //                      In0)))
  // Note that Mask0 is never used: lanes for which no path reaches this phi and
  // are essentially undef are taken from In0.
  bool OnlyFirstLaneUsed = vputils::onlyFirstLaneUsed(this);
  Value *Result = nullptr;
  for (unsigned In = 0; In < NumIncoming; ++In) {
    // We might have single edge PHIs (blocks) - use an identity
    // 'select' for the first PHI operand.
    Value *In0 = State.get(getIncomingValue(In), OnlyFirstLaneUsed);
    if (In == 0)
      Result = In0; // Initialize with the first incoming value.
    else {
      // Select between the current value and the previous incoming edge
      // based on the incoming mask.
      Value *Cond = State.get(getMask(In), OnlyFirstLaneUsed);
      Result = State.Builder.CreateSelect(Cond, In0, Result, "predphi");
    }
  }
  State.set(this, Result, OnlyFirstLaneUsed);
}
 
InstructionCost VPBlendRecipe::computeCost(ElementCount VF,
                                           VPCostContext &Ctx) const {
  TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
 
  // Handle cases where only the first lane is used the same way as the legacy
  // cost model.
  if (vputils::onlyFirstLaneUsed(this))
    return Ctx.TTI.getCFInstrCost(Instruction::PHI, CostKind);
 
  Type *ResultTy = toVectorTy(Ctx.Types.inferScalarType(this), VF);
  Type *CmpTy = toVectorTy(Type::getInt1Ty(Ctx.Types.getContext()), VF);
  return (getNumIncomingValues() - 1) *
         Ctx.TTI.getCmpSelInstrCost(Instruction::Select, ResultTy, CmpTy,
                                    CmpInst::BAD_ICMP_PREDICATE, CostKind);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPBlendRecipe::print(raw_ostream &O, const Twine &Indent,
                          VPSlotTracker &SlotTracker) const {
  O << Indent << "BLEND ";
  printAsOperand(O, SlotTracker);
  O << " =";
  if (getNumIncomingValues() == 1) {
    // Not a User of any mask: not really blending, this is a
    // single-predecessor phi.
    O << " ";
    getIncomingValue(0)->printAsOperand(O, SlotTracker);
  } else {
    for (unsigned I = 0, E = getNumIncomingValues(); I < E; ++I) {
      O << " ";
      getIncomingValue(I)->printAsOperand(O, SlotTracker);
      if (I == 0)
        continue;
      O << "/";
      getMask(I)->printAsOperand(O, SlotTracker);
    }
  }
}
#endif
 
void VPReductionRecipe::execute(VPTransformState &State) {
  assert(!State.Lane && "Reduction being replicated.");
  Value *PrevInChain = State.get(getChainOp(), /*IsScalar*/ true);
  RecurKind Kind = RdxDesc.getRecurrenceKind();
  // Propagate the fast-math flags carried by the underlying instruction.
  IRBuilderBase::FastMathFlagGuard FMFGuard(State.Builder);
  State.Builder.setFastMathFlags(RdxDesc.getFastMathFlags());
  State.setDebugLocFrom(getDebugLoc());
  Value *NewVecOp = State.get(getVecOp());
  if (VPValue *Cond = getCondOp()) {
    Value *NewCond = State.get(Cond, State.VF.isScalar());
    VectorType *VecTy = dyn_cast<VectorType>(NewVecOp->getType());
    Type *ElementTy = VecTy ? VecTy->getElementType() : NewVecOp->getType();
 
    Value *Start;
    if (RecurrenceDescriptor::isAnyOfRecurrenceKind(Kind))
      Start = RdxDesc.getRecurrenceStartValue();
    else
      Start = llvm::getRecurrenceIdentity(Kind, ElementTy,
                                          RdxDesc.getFastMathFlags());
    if (State.VF.isVector())
      Start = State.Builder.CreateVectorSplat(VecTy->getElementCount(), Start);
 
    Value *Select = State.Builder.CreateSelect(NewCond, NewVecOp, Start);
    NewVecOp = Select;
  }
  Value *NewRed;
  Value *NextInChain;
  if (IsOrdered) {
    if (State.VF.isVector())
      NewRed =
          createOrderedReduction(State.Builder, RdxDesc, NewVecOp, PrevInChain);
    else
      NewRed = State.Builder.CreateBinOp(
          (Instruction::BinaryOps)RdxDesc.getOpcode(), PrevInChain, NewVecOp);
    PrevInChain = NewRed;
    NextInChain = NewRed;
  } else {
    PrevInChain = State.get(getChainOp(), /*IsScalar*/ true);
    NewRed = createReduction(State.Builder, RdxDesc, NewVecOp);
    if (RecurrenceDescriptor::isMinMaxRecurrenceKind(Kind))
      NextInChain = createMinMaxOp(State.Builder, RdxDesc.getRecurrenceKind(),
                                   NewRed, PrevInChain);
    else
      NextInChain = State.Builder.CreateBinOp(
          (Instruction::BinaryOps)RdxDesc.getOpcode(), NewRed, PrevInChain);
  }
  State.set(this, NextInChain, /*IsScalar*/ true);
}
 
void VPReductionEVLRecipe::execute(VPTransformState &State) {
  assert(!State.Lane && "Reduction being replicated.");
 
  auto &Builder = State.Builder;
  // Propagate the fast-math flags carried by the underlying instruction.
  IRBuilderBase::FastMathFlagGuard FMFGuard(Builder);
  const RecurrenceDescriptor &RdxDesc = getRecurrenceDescriptor();
  Builder.setFastMathFlags(RdxDesc.getFastMathFlags());
 
  RecurKind Kind = RdxDesc.getRecurrenceKind();
  Value *Prev = State.get(getChainOp(), /*IsScalar*/ true);
  Value *VecOp = State.get(getVecOp());
  Value *EVL = State.get(getEVL(), VPLane(0));
 
  VectorBuilder VBuilder(Builder);
  VBuilder.setEVL(EVL);
  Value *Mask;
  // TODO: move the all-true mask generation into VectorBuilder.
  if (VPValue *CondOp = getCondOp())
    Mask = State.get(CondOp);
  else
    Mask = Builder.CreateVectorSplat(State.VF, Builder.getTrue());
  VBuilder.setMask(Mask);
 
  Value *NewRed;
  if (isOrdered()) {
    NewRed = createOrderedReduction(VBuilder, RdxDesc, VecOp, Prev);
  } else {
    NewRed = createSimpleReduction(VBuilder, VecOp, RdxDesc);
    if (RecurrenceDescriptor::isMinMaxRecurrenceKind(Kind))
      NewRed = createMinMaxOp(Builder, Kind, NewRed, Prev);
    else
      NewRed = Builder.CreateBinOp((Instruction::BinaryOps)RdxDesc.getOpcode(),
                                   NewRed, Prev);
  }
  State.set(this, NewRed, /*IsScalar*/ true);
}
 
InstructionCost VPReductionRecipe::computeCost(ElementCount VF,
                                               VPCostContext &Ctx) const {
  RecurKind RdxKind = RdxDesc.getRecurrenceKind();
  Type *ElementTy = Ctx.Types.inferScalarType(this);
  auto *VectorTy = cast<VectorType>(toVectorTy(ElementTy, VF));
  TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
  unsigned Opcode = RdxDesc.getOpcode();
 
  // TODO: Support any-of and in-loop reductions.
  assert(
      (!RecurrenceDescriptor::isAnyOfRecurrenceKind(RdxKind) ||
       ForceTargetInstructionCost.getNumOccurrences() > 0) &&
      "Any-of reduction not implemented in VPlan-based cost model currently.");
  assert(
      (!cast<VPReductionPHIRecipe>(getOperand(0))->isInLoop() ||
       ForceTargetInstructionCost.getNumOccurrences() > 0) &&
      "In-loop reduction not implemented in VPlan-based cost model currently.");
 
  assert(ElementTy->getTypeID() == RdxDesc.getRecurrenceType()->getTypeID() &&
         "Inferred type and recurrence type mismatch.");
 
  // Cost = Reduction cost + BinOp cost
  InstructionCost Cost =
      Ctx.TTI.getArithmeticInstrCost(Opcode, ElementTy, CostKind);
  if (RecurrenceDescriptor::isMinMaxRecurrenceKind(RdxKind)) {
    Intrinsic::ID Id = getMinMaxReductionIntrinsicOp(RdxKind);
    return Cost + Ctx.TTI.getMinMaxReductionCost(
                      Id, VectorTy, RdxDesc.getFastMathFlags(), CostKind);
  }
 
  return Cost + Ctx.TTI.getArithmeticReductionCost(
                    Opcode, VectorTy, RdxDesc.getFastMathFlags(), CostKind);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPReductionRecipe::print(raw_ostream &O, const Twine &Indent,
                              VPSlotTracker &SlotTracker) const {
  O << Indent << "REDUCE ";
  printAsOperand(O, SlotTracker);
  O << " = ";
  getChainOp()->printAsOperand(O, SlotTracker);
  O << " +";
  if (isa<FPMathOperator>(getUnderlyingInstr()))
    O << getUnderlyingInstr()->getFastMathFlags();
  O << " reduce." << Instruction::getOpcodeName(RdxDesc.getOpcode()) << " (";
  getVecOp()->printAsOperand(O, SlotTracker);
  if (isConditional()) {
    O << ", ";
    getCondOp()->printAsOperand(O, SlotTracker);
  }
  O << ")";
  if (RdxDesc.IntermediateStore)
    O << " (with final reduction value stored in invariant address sank "
         "outside of loop)";
}
 
void VPReductionEVLRecipe::print(raw_ostream &O, const Twine &Indent,
                                 VPSlotTracker &SlotTracker) const {
  const RecurrenceDescriptor &RdxDesc = getRecurrenceDescriptor();
  O << Indent << "REDUCE ";
  printAsOperand(O, SlotTracker);
  O << " = ";
  getChainOp()->printAsOperand(O, SlotTracker);
  O << " +";
  if (isa<FPMathOperator>(getUnderlyingInstr()))
    O << getUnderlyingInstr()->getFastMathFlags();
  O << " vp.reduce." << Instruction::getOpcodeName(RdxDesc.getOpcode()) << " (";
  getVecOp()->printAsOperand(O, SlotTracker);
  O << ", ";
  getEVL()->printAsOperand(O, SlotTracker);
  if (isConditional()) {
    O << ", ";
    getCondOp()->printAsOperand(O, SlotTracker);
  }
  O << ")";
  if (RdxDesc.IntermediateStore)
    O << " (with final reduction value stored in invariant address sank "
         "outside of loop)";
}
#endif
 
bool VPReplicateRecipe::shouldPack() const {
  // Find if the recipe is used by a widened recipe via an intervening
  // VPPredInstPHIRecipe. In this case, also pack the scalar values in a vector.
  return any_of(users(), [](const VPUser *U) {
    if (auto *PredR = dyn_cast<VPPredInstPHIRecipe>(U))
      return any_of(PredR->users(), [PredR](const VPUser *U) {
        return !U->usesScalars(PredR);
      });
    return false;
  });
}
 
InstructionCost VPReplicateRecipe::computeCost(ElementCount VF,
                                               VPCostContext &Ctx) const {
  Instruction *UI = cast<Instruction>(getUnderlyingValue());
  // VPReplicateRecipe may be cloned as part of an existing VPlan-to-VPlan
  // transform, avoid computing their cost multiple times for now.
  Ctx.SkipCostComputation.insert(UI);
  return Ctx.getLegacyCost(UI, VF);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPReplicateRecipe::print(raw_ostream &O, const Twine &Indent,
                              VPSlotTracker &SlotTracker) const {
  O << Indent << (IsUniform ? "CLONE " : "REPLICATE ");
 
  if (!getUnderlyingInstr()->getType()->isVoidTy()) {
    printAsOperand(O, SlotTracker);
    O << " = ";
  }
  if (auto *CB = dyn_cast<CallBase>(getUnderlyingInstr())) {
    O << "call";
    printFlags(O);
    O << "@" << CB->getCalledFunction()->getName() << "(";
    interleaveComma(make_range(op_begin(), op_begin() + (getNumOperands() - 1)),
                    O, [&O, &SlotTracker](VPValue *Op) {
                      Op->printAsOperand(O, SlotTracker);
                    });
    O << ")";
  } else {
    O << Instruction::getOpcodeName(getUnderlyingInstr()->getOpcode());
    printFlags(O);
    printOperands(O, SlotTracker);
  }
 
  if (shouldPack())
    O << " (S->V)";
}
#endif
 
Value *VPScalarCastRecipe ::generate(VPTransformState &State) {
  State.setDebugLocFrom(getDebugLoc());
  assert(vputils::onlyFirstLaneUsed(this) &&
         "Codegen only implemented for first lane.");
  switch (Opcode) {
  case Instruction::SExt:
  case Instruction::ZExt:
  case Instruction::Trunc: {
    // Note: SExt/ZExt not used yet.
    Value *Op = State.get(getOperand(0), VPLane(0));
    return State.Builder.CreateCast(Instruction::CastOps(Opcode), Op, ResultTy);
  }
  default:
    llvm_unreachable("opcode not implemented yet");
  }
}
 
void VPScalarCastRecipe ::execute(VPTransformState &State) {
  State.set(this, generate(State), VPLane(0));
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPScalarCastRecipe ::print(raw_ostream &O, const Twine &Indent,
                                VPSlotTracker &SlotTracker) const {
  O << Indent << "SCALAR-CAST ";
  printAsOperand(O, SlotTracker);
  O << " = " << Instruction::getOpcodeName(Opcode) << " ";
  printOperands(O, SlotTracker);
  O << " to " << *ResultTy;
}
#endif
 
void VPBranchOnMaskRecipe::execute(VPTransformState &State) {
  assert(State.Lane && "Branch on Mask works only on single instance.");
 
  unsigned Lane = State.Lane->getKnownLane();
 
  Value *ConditionBit = nullptr;
  VPValue *BlockInMask = getMask();
  if (BlockInMask) {
    ConditionBit = State.get(BlockInMask);
    if (ConditionBit->getType()->isVectorTy())
      ConditionBit = State.Builder.CreateExtractElement(
          ConditionBit, State.Builder.getInt32(Lane));
  } else // Block in mask is all-one.
    ConditionBit = State.Builder.getTrue();
 
  // Replace the temporary unreachable terminator with a new conditional branch,
  // whose two destinations will be set later when they are created.
  auto *CurrentTerminator = State.CFG.PrevBB->getTerminator();
  assert(isa<UnreachableInst>(CurrentTerminator) &&
         "Expected to replace unreachable terminator with conditional branch.");
  auto *CondBr = BranchInst::Create(State.CFG.PrevBB, nullptr, ConditionBit);
  CondBr->setSuccessor(0, nullptr);
  ReplaceInstWithInst(CurrentTerminator, CondBr);
}
 
InstructionCost VPBranchOnMaskRecipe::computeCost(ElementCount VF,
                                                  VPCostContext &Ctx) const {
  // The legacy cost model doesn't assign costs to branches for individual
  // replicate regions. Match the current behavior in the VPlan cost model for
  // now.
  return 0;
}
 
void VPPredInstPHIRecipe::execute(VPTransformState &State) {
  State.setDebugLocFrom(getDebugLoc());
  assert(State.Lane && "Predicated instruction PHI works per instance.");
  Instruction *ScalarPredInst =
      cast<Instruction>(State.get(getOperand(0), *State.Lane));
  BasicBlock *PredicatedBB = ScalarPredInst->getParent();
  BasicBlock *PredicatingBB = PredicatedBB->getSinglePredecessor();
  assert(PredicatingBB && "Predicated block has no single predecessor.");
  assert(isa<VPReplicateRecipe>(getOperand(0)) &&
         "operand must be VPReplicateRecipe");
 
  // By current pack/unpack logic we need to generate only a single phi node: if
  // a vector value for the predicated instruction exists at this point it means
  // the instruction has vector users only, and a phi for the vector value is
  // needed. In this case the recipe of the predicated instruction is marked to
  // also do that packing, thereby "hoisting" the insert-element sequence.
  // Otherwise, a phi node for the scalar value is needed.
  if (State.hasVectorValue(getOperand(0))) {
    Value *VectorValue = State.get(getOperand(0));
    InsertElementInst *IEI = cast<InsertElementInst>(VectorValue);
    PHINode *VPhi = State.Builder.CreatePHI(IEI->getType(), 2);
    VPhi->addIncoming(IEI->getOperand(0), PredicatingBB); // Unmodified vector.
    VPhi->addIncoming(IEI, PredicatedBB); // New vector with inserted element.
    if (State.hasVectorValue(this))
      State.reset(this, VPhi);
    else
      State.set(this, VPhi);
    // NOTE: Currently we need to update the value of the operand, so the next
    // predicated iteration inserts its generated value in the correct vector.
    State.reset(getOperand(0), VPhi);
  } else {
    if (vputils::onlyFirstLaneUsed(this) && !State.Lane->isFirstLane())
      return;
 
    Type *PredInstType = getOperand(0)->getUnderlyingValue()->getType();
    PHINode *Phi = State.Builder.CreatePHI(PredInstType, 2);
    Phi->addIncoming(PoisonValue::get(ScalarPredInst->getType()),
                     PredicatingBB);
    Phi->addIncoming(ScalarPredInst, PredicatedBB);
    if (State.hasScalarValue(this, *State.Lane))
      State.reset(this, Phi, *State.Lane);
    else
      State.set(this, Phi, *State.Lane);
    // NOTE: Currently we need to update the value of the operand, so the next
    // predicated iteration inserts its generated value in the correct vector.
    State.reset(getOperand(0), Phi, *State.Lane);
  }
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPPredInstPHIRecipe::print(raw_ostream &O, const Twine &Indent,
                                VPSlotTracker &SlotTracker) const {
  O << Indent << "PHI-PREDICATED-INSTRUCTION ";
  printAsOperand(O, SlotTracker);
  O << " = ";
  printOperands(O, SlotTracker);
}
#endif
 
InstructionCost VPWidenMemoryRecipe::computeCost(ElementCount VF,
                                                 VPCostContext &Ctx) const {
  Type *Ty = toVectorTy(getLoadStoreType(&Ingredient), VF);
  const Align Alignment =
      getLoadStoreAlignment(const_cast<Instruction *>(&Ingredient));
  unsigned AS =
      getLoadStoreAddressSpace(const_cast<Instruction *>(&Ingredient));
  TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
 
  if (!Consecutive) {
    // TODO: Using the original IR may not be accurate.
    // Currently, ARM will use the underlying IR to calculate gather/scatter
    // instruction cost.
    const Value *Ptr = getLoadStorePointerOperand(&Ingredient);
    assert(!Reverse &&
           "Inconsecutive memory access should not have the order.");
    return Ctx.TTI.getAddressComputationCost(Ty) +
           Ctx.TTI.getGatherScatterOpCost(Ingredient.getOpcode(), Ty, Ptr,
                                          IsMasked, Alignment, CostKind,
                                          &Ingredient);
  }
 
  InstructionCost Cost = 0;
  if (IsMasked) {
    Cost += Ctx.TTI.getMaskedMemoryOpCost(Ingredient.getOpcode(), Ty, Alignment,
                                          AS, CostKind);
  } else {
    TTI::OperandValueInfo OpInfo =
        Ctx.TTI.getOperandInfo(Ingredient.getOperand(0));
    Cost += Ctx.TTI.getMemoryOpCost(Ingredient.getOpcode(), Ty, Alignment, AS,
                                    CostKind, OpInfo, &Ingredient);
  }
  if (!Reverse)
    return Cost;
 
  return Cost += Ctx.TTI.getShuffleCost(TargetTransformInfo::SK_Reverse,
                                        cast<VectorType>(Ty), {}, CostKind, 0);
}
 
void VPWidenLoadRecipe::execute(VPTransformState &State) {
  auto *LI = cast<LoadInst>(&Ingredient);
 
  Type *ScalarDataTy = getLoadStoreType(&Ingredient);
  auto *DataTy = VectorType::get(ScalarDataTy, State.VF);
  const Align Alignment = getLoadStoreAlignment(&Ingredient);
  bool CreateGather = !isConsecutive();
 
  auto &Builder = State.Builder;
  State.setDebugLocFrom(getDebugLoc());
  Value *Mask = nullptr;
  if (auto *VPMask = getMask()) {
    // Mask reversal is only needed for non-all-one (null) masks, as reverse
    // of a null all-one mask is a null mask.
    Mask = State.get(VPMask);
    if (isReverse())
      Mask = Builder.CreateVectorReverse(Mask, "reverse");
  }
 
  Value *Addr = State.get(getAddr(), /*IsScalar*/ !CreateGather);
  Value *NewLI;
  if (CreateGather) {
    NewLI = Builder.CreateMaskedGather(DataTy, Addr, Alignment, Mask, nullptr,
                                       "wide.masked.gather");
  } else if (Mask) {
    NewLI =
        Builder.CreateMaskedLoad(DataTy, Addr, Alignment, Mask,
                                 PoisonValue::get(DataTy), "wide.masked.load");
  } else {
    NewLI = Builder.CreateAlignedLoad(DataTy, Addr, Alignment, "wide.load");
  }
  // Add metadata to the load, but setVectorValue to the reverse shuffle.
  State.addMetadata(NewLI, LI);
  if (Reverse)
    NewLI = Builder.CreateVectorReverse(NewLI, "reverse");
  State.set(this, NewLI);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPWidenLoadRecipe::print(raw_ostream &O, const Twine &Indent,
                              VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN ";
  printAsOperand(O, SlotTracker);
  O << " = load ";
  printOperands(O, SlotTracker);
}
#endif
 
/// Use all-true mask for reverse rather than actual mask, as it avoids a
/// dependence w/o affecting the result.
static Instruction *createReverseEVL(IRBuilderBase &Builder, Value *Operand,
                                     Value *EVL, const Twine &Name) {
  VectorType *ValTy = cast<VectorType>(Operand->getType());
  Value *AllTrueMask =
      Builder.CreateVectorSplat(ValTy->getElementCount(), Builder.getTrue());
  return Builder.CreateIntrinsic(ValTy, Intrinsic::experimental_vp_reverse,
                                 {Operand, AllTrueMask, EVL}, nullptr, Name);
}
 
void VPWidenLoadEVLRecipe::execute(VPTransformState &State) {
  auto *LI = cast<LoadInst>(&Ingredient);
 
  Type *ScalarDataTy = getLoadStoreType(&Ingredient);
  auto *DataTy = VectorType::get(ScalarDataTy, State.VF);
  const Align Alignment = getLoadStoreAlignment(&Ingredient);
  bool CreateGather = !isConsecutive();
 
  auto &Builder = State.Builder;
  State.setDebugLocFrom(getDebugLoc());
  CallInst *NewLI;
  Value *EVL = State.get(getEVL(), VPLane(0));
  Value *Addr = State.get(getAddr(), !CreateGather);
  Value *Mask = nullptr;
  if (VPValue *VPMask = getMask()) {
    Mask = State.get(VPMask);
    if (isReverse())
      Mask = createReverseEVL(Builder, Mask, EVL, "vp.reverse.mask");
  } else {
    Mask = Builder.CreateVectorSplat(State.VF, Builder.getTrue());
  }
 
  if (CreateGather) {
    NewLI =
        Builder.CreateIntrinsic(DataTy, Intrinsic::vp_gather, {Addr, Mask, EVL},
                                nullptr, "wide.masked.gather");
  } else {
    VectorBuilder VBuilder(Builder);
    VBuilder.setEVL(EVL).setMask(Mask);
    NewLI = cast<CallInst>(VBuilder.createVectorInstruction(
        Instruction::Load, DataTy, Addr, "vp.op.load"));
  }
  NewLI->addParamAttr(
      0, Attribute::getWithAlignment(NewLI->getContext(), Alignment));
  State.addMetadata(NewLI, LI);
  Instruction *Res = NewLI;
  if (isReverse())
    Res = createReverseEVL(Builder, Res, EVL, "vp.reverse");
  State.set(this, Res);
}
 
InstructionCost VPWidenLoadEVLRecipe::computeCost(ElementCount VF,
                                                  VPCostContext &Ctx) const {
  if (!Consecutive || IsMasked)
    return VPWidenMemoryRecipe::computeCost(VF, Ctx);
 
  // We need to use the getMaskedMemoryOpCost() instead of getMemoryOpCost()
  // here because the EVL recipes using EVL to replace the tail mask. But in the
  // legacy model, it will always calculate the cost of mask.
  // TODO: Using getMemoryOpCost() instead of getMaskedMemoryOpCost when we
  // don't need to compare to the legacy cost model.
  Type *Ty = toVectorTy(getLoadStoreType(&Ingredient), VF);
  const Align Alignment =
      getLoadStoreAlignment(const_cast<Instruction *>(&Ingredient));
  unsigned AS =
      getLoadStoreAddressSpace(const_cast<Instruction *>(&Ingredient));
  TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
  InstructionCost Cost = Ctx.TTI.getMaskedMemoryOpCost(
      Ingredient.getOpcode(), Ty, Alignment, AS, CostKind);
  if (!Reverse)
    return Cost;
 
  return Cost + Ctx.TTI.getShuffleCost(TargetTransformInfo::SK_Reverse,
                                       cast<VectorType>(Ty), {}, CostKind, 0);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPWidenLoadEVLRecipe::print(raw_ostream &O, const Twine &Indent,
                                 VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN ";
  printAsOperand(O, SlotTracker);
  O << " = vp.load ";
  printOperands(O, SlotTracker);
}
#endif
 
void VPWidenStoreRecipe::execute(VPTransformState &State) {
  auto *SI = cast<StoreInst>(&Ingredient);
 
  VPValue *StoredVPValue = getStoredValue();
  bool CreateScatter = !isConsecutive();
  const Align Alignment = getLoadStoreAlignment(&Ingredient);
 
  auto &Builder = State.Builder;
  State.setDebugLocFrom(getDebugLoc());
 
  Value *Mask = nullptr;
  if (auto *VPMask = getMask()) {
    // Mask reversal is only needed for non-all-one (null) masks, as reverse
    // of a null all-one mask is a null mask.
    Mask = State.get(VPMask);
    if (isReverse())
      Mask = Builder.CreateVectorReverse(Mask, "reverse");
  }
 
  Value *StoredVal = State.get(StoredVPValue);
  if (isReverse()) {
    // If we store to reverse consecutive memory locations, then we need
    // to reverse the order of elements in the stored value.
    StoredVal = Builder.CreateVectorReverse(StoredVal, "reverse");
    // We don't want to update the value in the map as it might be used in
    // another expression. So don't call resetVectorValue(StoredVal).
  }
  Value *Addr = State.get(getAddr(), /*IsScalar*/ !CreateScatter);
  Instruction *NewSI = nullptr;
  if (CreateScatter)
    NewSI = Builder.CreateMaskedScatter(StoredVal, Addr, Alignment, Mask);
  else if (Mask)
    NewSI = Builder.CreateMaskedStore(StoredVal, Addr, Alignment, Mask);
  else
    NewSI = Builder.CreateAlignedStore(StoredVal, Addr, Alignment);
  State.addMetadata(NewSI, SI);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPWidenStoreRecipe::print(raw_ostream &O, const Twine &Indent,
                               VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN store ";
  printOperands(O, SlotTracker);
}
#endif
 
void VPWidenStoreEVLRecipe::execute(VPTransformState &State) {
  auto *SI = cast<StoreInst>(&Ingredient);
 
  VPValue *StoredValue = getStoredValue();
  bool CreateScatter = !isConsecutive();
  const Align Alignment = getLoadStoreAlignment(&Ingredient);
 
  auto &Builder = State.Builder;
  State.setDebugLocFrom(getDebugLoc());
 
  CallInst *NewSI = nullptr;
  Value *StoredVal = State.get(StoredValue);
  Value *EVL = State.get(getEVL(), VPLane(0));
  if (isReverse())
    StoredVal = createReverseEVL(Builder, StoredVal, EVL, "vp.reverse");
  Value *Mask = nullptr;
  if (VPValue *VPMask = getMask()) {
    Mask = State.get(VPMask);
    if (isReverse())
      Mask = createReverseEVL(Builder, Mask, EVL, "vp.reverse.mask");
  } else {
    Mask = Builder.CreateVectorSplat(State.VF, Builder.getTrue());
  }
  Value *Addr = State.get(getAddr(), !CreateScatter);
  if (CreateScatter) {
    NewSI = Builder.CreateIntrinsic(Type::getVoidTy(EVL->getContext()),
                                    Intrinsic::vp_scatter,
                                    {StoredVal, Addr, Mask, EVL});
  } else {
    VectorBuilder VBuilder(Builder);
    VBuilder.setEVL(EVL).setMask(Mask);
    NewSI = cast<CallInst>(VBuilder.createVectorInstruction(
        Instruction::Store, Type::getVoidTy(EVL->getContext()),
        {StoredVal, Addr}));
  }
  NewSI->addParamAttr(
      1, Attribute::getWithAlignment(NewSI->getContext(), Alignment));
  State.addMetadata(NewSI, SI);
}
 
InstructionCost VPWidenStoreEVLRecipe::computeCost(ElementCount VF,
                                                   VPCostContext &Ctx) const {
  if (!Consecutive || IsMasked)
    return VPWidenMemoryRecipe::computeCost(VF, Ctx);
 
  // We need to use the getMaskedMemoryOpCost() instead of getMemoryOpCost()
  // here because the EVL recipes using EVL to replace the tail mask. But in the
  // legacy model, it will always calculate the cost of mask.
  // TODO: Using getMemoryOpCost() instead of getMaskedMemoryOpCost when we
  // don't need to compare to the legacy cost model.
  Type *Ty = toVectorTy(getLoadStoreType(&Ingredient), VF);
  const Align Alignment =
      getLoadStoreAlignment(const_cast<Instruction *>(&Ingredient));
  unsigned AS =
      getLoadStoreAddressSpace(const_cast<Instruction *>(&Ingredient));
  TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
  InstructionCost Cost = Ctx.TTI.getMaskedMemoryOpCost(
      Ingredient.getOpcode(), Ty, Alignment, AS, CostKind);
  if (!Reverse)
    return Cost;
 
  return Cost + Ctx.TTI.getShuffleCost(TargetTransformInfo::SK_Reverse,
                                       cast<VectorType>(Ty), {}, CostKind, 0);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPWidenStoreEVLRecipe::print(raw_ostream &O, const Twine &Indent,
                                  VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN vp.store ";
  printOperands(O, SlotTracker);
}
#endif
 
static Value *createBitOrPointerCast(IRBuilderBase &Builder, Value *V,
                                     VectorType *DstVTy, const DataLayout &DL) {
  // Verify that V is a vector type with same number of elements as DstVTy.
  auto VF = DstVTy->getElementCount();
  auto *SrcVecTy = cast<VectorType>(V->getType());
  assert(VF == SrcVecTy->getElementCount() && "Vector dimensions do not match");
  Type *SrcElemTy = SrcVecTy->getElementType();
  Type *DstElemTy = DstVTy->getElementType();
  assert((DL.getTypeSizeInBits(SrcElemTy) == DL.getTypeSizeInBits(DstElemTy)) &&
         "Vector elements must have same size");
 
  // Do a direct cast if element types are castable.
  if (CastInst::isBitOrNoopPointerCastable(SrcElemTy, DstElemTy, DL)) {
    return Builder.CreateBitOrPointerCast(V, DstVTy);
  }
  // V cannot be directly casted to desired vector type.
  // May happen when V is a floating point vector but DstVTy is a vector of
  // pointers or vice-versa. Handle this using a two-step bitcast using an
  // intermediate Integer type for the bitcast i.e. Ptr <-> Int <-> Float.
  assert((DstElemTy->isPointerTy() != SrcElemTy->isPointerTy()) &&
         "Only one type should be a pointer type");
  assert((DstElemTy->isFloatingPointTy() != SrcElemTy->isFloatingPointTy()) &&
         "Only one type should be a floating point type");
  Type *IntTy =
      IntegerType::getIntNTy(V->getContext(), DL.getTypeSizeInBits(SrcElemTy));
  auto *VecIntTy = VectorType::get(IntTy, VF);
  Value *CastVal = Builder.CreateBitOrPointerCast(V, VecIntTy);
  return Builder.CreateBitOrPointerCast(CastVal, DstVTy);
}
 
/// Return a vector containing interleaved elements from multiple
/// smaller input vectors.
static Value *interleaveVectors(IRBuilderBase &Builder, ArrayRef<Value *> Vals,
                                const Twine &Name) {
  unsigned Factor = Vals.size();
  assert(Factor > 1 && "Tried to interleave invalid number of vectors");
 
  VectorType *VecTy = cast<VectorType>(Vals[0]->getType());
#ifndef NDEBUG
  for (Value *Val : Vals)
    assert(Val->getType() == VecTy && "Tried to interleave mismatched types");
#endif
 
  // Scalable vectors cannot use arbitrary shufflevectors (only splats), so
  // must use intrinsics to interleave.
  if (VecTy->isScalableTy()) {
    VectorType *WideVecTy = VectorType::getDoubleElementsVectorType(VecTy);
    return Builder.CreateIntrinsic(WideVecTy, Intrinsic::vector_interleave2,
                                   Vals,
                                   /*FMFSource=*/nullptr, Name);
  }
 
  // Fixed length. Start by concatenating all vectors into a wide vector.
  Value *WideVec = concatenateVectors(Builder, Vals);
 
  // Interleave the elements into the wide vector.
  const unsigned NumElts = VecTy->getElementCount().getFixedValue();
  return Builder.CreateShuffleVector(
      WideVec, createInterleaveMask(NumElts, Factor), Name);
}
 
// Try to vectorize the interleave group that \p Instr belongs to.
//
// E.g. Translate following interleaved load group (factor = 3):
//   for (i = 0; i < N; i+=3) {
//     R = Pic[i];             // Member of index 0
//     G = Pic[i+1];           // Member of index 1
//     B = Pic[i+2];           // Member of index 2
//     ... // do something to R, G, B
//   }
// To:
//   %wide.vec = load <12 x i32>                       ; Read 4 tuples of R,G,B
//   %R.vec = shuffle %wide.vec, poison, <0, 3, 6, 9>   ; R elements
//   %G.vec = shuffle %wide.vec, poison, <1, 4, 7, 10>  ; G elements
//   %B.vec = shuffle %wide.vec, poison, <2, 5, 8, 11>  ; B elements
//
// Or translate following interleaved store group (factor = 3):
//   for (i = 0; i < N; i+=3) {
//     ... do something to R, G, B
//     Pic[i]   = R;           // Member of index 0
//     Pic[i+1] = G;           // Member of index 1
//     Pic[i+2] = B;           // Member of index 2
//   }
// To:
//   %R_G.vec = shuffle %R.vec, %G.vec, <0, 1, 2, ..., 7>
//   %B_U.vec = shuffle %B.vec, poison, <0, 1, 2, 3, u, u, u, u>
//   %interleaved.vec = shuffle %R_G.vec, %B_U.vec,
//        <0, 4, 8, 1, 5, 9, 2, 6, 10, 3, 7, 11>    ; Interleave R,G,B elements
//   store <12 x i32> %interleaved.vec              ; Write 4 tuples of R,G,B
void VPInterleaveRecipe::execute(VPTransformState &State) {
  assert(!State.Lane && "Interleave group being replicated.");
  const InterleaveGroup<Instruction> *Group = IG;
  Instruction *Instr = Group->getInsertPos();
 
  // Prepare for the vector type of the interleaved load/store.
  Type *ScalarTy = getLoadStoreType(Instr);
  unsigned InterleaveFactor = Group->getFactor();
  auto *VecTy = VectorType::get(ScalarTy, State.VF * InterleaveFactor);
 
  // TODO: extend the masked interleaved-group support to reversed access.
  VPValue *BlockInMask = getMask();
  assert((!BlockInMask || !Group->isReverse()) &&
         "Reversed masked interleave-group not supported.");
 
  VPValue *Addr = getAddr();
  Value *ResAddr = State.get(Addr, VPLane(0));
  if (auto *I = dyn_cast<Instruction>(ResAddr))
    State.setDebugLocFrom(I->getDebugLoc());
 
  // If the group is reverse, adjust the index to refer to the last vector lane
  // instead of the first. We adjust the index from the first vector lane,
  // rather than directly getting the pointer for lane VF - 1, because the
  // pointer operand of the interleaved access is supposed to be uniform.
  if (Group->isReverse()) {
    Value *RuntimeVF =
        getRuntimeVF(State.Builder, State.Builder.getInt32Ty(), State.VF);
    Value *Index =
        State.Builder.CreateSub(RuntimeVF, State.Builder.getInt32(1));
    Index = State.Builder.CreateMul(Index,
                                    State.Builder.getInt32(Group->getFactor()));
    Index = State.Builder.CreateNeg(Index);
 
    bool InBounds = false;
    if (auto *Gep = dyn_cast<GetElementPtrInst>(ResAddr->stripPointerCasts()))
      InBounds = Gep->isInBounds();
    ResAddr = State.Builder.CreateGEP(ScalarTy, ResAddr, Index, "", InBounds);
  }
 
  State.setDebugLocFrom(Instr->getDebugLoc());
  Value *PoisonVec = PoisonValue::get(VecTy);
 
  auto CreateGroupMask = [&BlockInMask, &State,
                          &InterleaveFactor](Value *MaskForGaps) -> Value * {
    if (State.VF.isScalable()) {
      assert(!MaskForGaps && "Interleaved groups with gaps are not supported.");
      assert(InterleaveFactor == 2 &&
             "Unsupported deinterleave factor for scalable vectors");
      auto *ResBlockInMask = State.get(BlockInMask);
      SmallVector<Value *, 2> Ops = {ResBlockInMask, ResBlockInMask};
      auto *MaskTy = VectorType::get(State.Builder.getInt1Ty(),
                                     State.VF.getKnownMinValue() * 2, true);
      return State.Builder.CreateIntrinsic(
          MaskTy, Intrinsic::vector_interleave2, Ops,
          /*FMFSource=*/nullptr, "interleaved.mask");
    }
 
    if (!BlockInMask)
      return MaskForGaps;
 
    Value *ResBlockInMask = State.get(BlockInMask);
    Value *ShuffledMask = State.Builder.CreateShuffleVector(
        ResBlockInMask,
        createReplicatedMask(InterleaveFactor, State.VF.getKnownMinValue()),
        "interleaved.mask");
    return MaskForGaps ? State.Builder.CreateBinOp(Instruction::And,
                                                   ShuffledMask, MaskForGaps)
                       : ShuffledMask;
  };
 
  const DataLayout &DL = Instr->getDataLayout();
  // Vectorize the interleaved load group.
  if (isa<LoadInst>(Instr)) {
    Value *MaskForGaps = nullptr;
    if (NeedsMaskForGaps) {
      MaskForGaps = createBitMaskForGaps(State.Builder,
                                         State.VF.getKnownMinValue(), *Group);
      assert(MaskForGaps && "Mask for Gaps is required but it is null");
    }
 
    Instruction *NewLoad;
    if (BlockInMask || MaskForGaps) {
      Value *GroupMask = CreateGroupMask(MaskForGaps);
      NewLoad = State.Builder.CreateMaskedLoad(VecTy, ResAddr,
                                               Group->getAlign(), GroupMask,
                                               PoisonVec, "wide.masked.vec");
    } else
      NewLoad = State.Builder.CreateAlignedLoad(VecTy, ResAddr,
                                                Group->getAlign(), "wide.vec");
    Group->addMetadata(NewLoad);
 
    ArrayRef<VPValue *> VPDefs = definedValues();
    const DataLayout &DL = State.CFG.PrevBB->getDataLayout();
    if (VecTy->isScalableTy()) {
      assert(InterleaveFactor == 2 &&
             "Unsupported deinterleave factor for scalable vectors");
 
        // Scalable vectors cannot use arbitrary shufflevectors (only splats),
        // so must use intrinsics to deinterleave.
      Value *DI = State.Builder.CreateIntrinsic(
          Intrinsic::vector_deinterleave2, VecTy, NewLoad,
          /*FMFSource=*/nullptr, "strided.vec");
      unsigned J = 0;
      for (unsigned I = 0; I < InterleaveFactor; ++I) {
        Instruction *Member = Group->getMember(I);
 
        if (!Member)
          continue;
 
        Value *StridedVec = State.Builder.CreateExtractValue(DI, I);
        // If this member has different type, cast the result type.
        if (Member->getType() != ScalarTy) {
          VectorType *OtherVTy = VectorType::get(Member->getType(), State.VF);
          StridedVec =
              createBitOrPointerCast(State.Builder, StridedVec, OtherVTy, DL);
        }
 
        if (Group->isReverse())
          StridedVec = State.Builder.CreateVectorReverse(StridedVec, "reverse");
 
        State.set(VPDefs[J], StridedVec);
        ++J;
      }
 
      return;
    }
 
    // For each member in the group, shuffle out the appropriate data from the
    // wide loads.
    unsigned J = 0;
    for (unsigned I = 0; I < InterleaveFactor; ++I) {
      Instruction *Member = Group->getMember(I);
 
      // Skip the gaps in the group.
      if (!Member)
        continue;
 
      auto StrideMask =
          createStrideMask(I, InterleaveFactor, State.VF.getKnownMinValue());
      Value *StridedVec =
          State.Builder.CreateShuffleVector(NewLoad, StrideMask, "strided.vec");
 
      // If this member has different type, cast the result type.
      if (Member->getType() != ScalarTy) {
        assert(!State.VF.isScalable() && "VF is assumed to be non scalable.");
        VectorType *OtherVTy = VectorType::get(Member->getType(), State.VF);
        StridedVec =
            createBitOrPointerCast(State.Builder, StridedVec, OtherVTy, DL);
      }
 
      if (Group->isReverse())
        StridedVec = State.Builder.CreateVectorReverse(StridedVec, "reverse");
 
      State.set(VPDefs[J], StridedVec);
      ++J;
    }
    return;
  }
 
  // The sub vector type for current instruction.
  auto *SubVT = VectorType::get(ScalarTy, State.VF);
 
  // Vectorize the interleaved store group.
  Value *MaskForGaps =
      createBitMaskForGaps(State.Builder, State.VF.getKnownMinValue(), *Group);
  assert((!MaskForGaps || !State.VF.isScalable()) &&
         "masking gaps for scalable vectors is not yet supported.");
  ArrayRef<VPValue *> StoredValues = getStoredValues();
  // Collect the stored vector from each member.
  SmallVector<Value *, 4> StoredVecs;
  unsigned StoredIdx = 0;
  for (unsigned i = 0; i < InterleaveFactor; i++) {
    assert((Group->getMember(i) || MaskForGaps) &&
           "Fail to get a member from an interleaved store group");
    Instruction *Member = Group->getMember(i);
 
    // Skip the gaps in the group.
    if (!Member) {
      Value *Undef = PoisonValue::get(SubVT);
      StoredVecs.push_back(Undef);
      continue;
    }
 
    Value *StoredVec = State.get(StoredValues[StoredIdx]);
    ++StoredIdx;
 
    if (Group->isReverse())
      StoredVec = State.Builder.CreateVectorReverse(StoredVec, "reverse");
 
    // If this member has different type, cast it to a unified type.
 
    if (StoredVec->getType() != SubVT)
      StoredVec = createBitOrPointerCast(State.Builder, StoredVec, SubVT, DL);
 
    StoredVecs.push_back(StoredVec);
  }
 
  // Interleave all the smaller vectors into one wider vector.
  Value *IVec = interleaveVectors(State.Builder, StoredVecs, "interleaved.vec");
  Instruction *NewStoreInstr;
  if (BlockInMask || MaskForGaps) {
    Value *GroupMask = CreateGroupMask(MaskForGaps);
    NewStoreInstr = State.Builder.CreateMaskedStore(
        IVec, ResAddr, Group->getAlign(), GroupMask);
  } else
    NewStoreInstr =
        State.Builder.CreateAlignedStore(IVec, ResAddr, Group->getAlign());
 
  Group->addMetadata(NewStoreInstr);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPInterleaveRecipe::print(raw_ostream &O, const Twine &Indent,
                               VPSlotTracker &SlotTracker) const {
  O << Indent << "INTERLEAVE-GROUP with factor " << IG->getFactor() << " at ";
  IG->getInsertPos()->printAsOperand(O, false);
  O << ", ";
  getAddr()->printAsOperand(O, SlotTracker);
  VPValue *Mask = getMask();
  if (Mask) {
    O << ", ";
    Mask->printAsOperand(O, SlotTracker);
  }
 
  unsigned OpIdx = 0;
  for (unsigned i = 0; i < IG->getFactor(); ++i) {
    if (!IG->getMember(i))
      continue;
    if (getNumStoreOperands() > 0) {
      O << "\n" << Indent << "  store ";
      getOperand(1 + OpIdx)->printAsOperand(O, SlotTracker);
      O << " to index " << i;
    } else {
      O << "\n" << Indent << "  ";
      getVPValue(OpIdx)->printAsOperand(O, SlotTracker);
      O << " = load from index " << i;
    }
    ++OpIdx;
  }
}
#endif
 
InstructionCost VPInterleaveRecipe::computeCost(ElementCount VF,
                                                VPCostContext &Ctx) const {
  Instruction *InsertPos = getInsertPos();
  // Find the VPValue index of the interleave group. We need to skip gaps.
  unsigned InsertPosIdx = 0;
  for (unsigned Idx = 0; IG->getFactor(); ++Idx)
    if (auto *Member = IG->getMember(Idx)) {
      if (Member == InsertPos)
        break;
      InsertPosIdx++;
    }
  Type *ValTy = Ctx.Types.inferScalarType(
      getNumDefinedValues() > 0 ? getVPValue(InsertPosIdx)
                                : getStoredValues()[InsertPosIdx]);
  auto *VectorTy = cast<VectorType>(toVectorTy(ValTy, VF));
  unsigned AS = getLoadStoreAddressSpace(InsertPos);
  enum TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
 
  unsigned InterleaveFactor = IG->getFactor();
  auto *WideVecTy = VectorType::get(ValTy, VF * InterleaveFactor);
 
  // Holds the indices of existing members in the interleaved group.
  SmallVector<unsigned, 4> Indices;
  for (unsigned IF = 0; IF < InterleaveFactor; IF++)
    if (IG->getMember(IF))
      Indices.push_back(IF);
 
  // Calculate the cost of the whole interleaved group.
  InstructionCost Cost = Ctx.TTI.getInterleavedMemoryOpCost(
      InsertPos->getOpcode(), WideVecTy, IG->getFactor(), Indices,
      IG->getAlign(), AS, CostKind, getMask(), NeedsMaskForGaps);
 
  if (!IG->isReverse())
    return Cost;
 
  return Cost + IG->getNumMembers() *
                    Ctx.TTI.getShuffleCost(TargetTransformInfo::SK_Reverse,
                                           VectorTy, std::nullopt, CostKind, 0);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPCanonicalIVPHIRecipe::print(raw_ostream &O, const Twine &Indent,
                                   VPSlotTracker &SlotTracker) const {
  O << Indent << "EMIT ";
  printAsOperand(O, SlotTracker);
  O << " = CANONICAL-INDUCTION ";
  printOperands(O, SlotTracker);
}
#endif
 
bool VPWidenPointerInductionRecipe::onlyScalarsGenerated(bool IsScalable) {
  return IsScalarAfterVectorization &&
         (!IsScalable || vputils::onlyFirstLaneUsed(this));
}
 
void VPWidenPointerInductionRecipe::execute(VPTransformState &State) {
  assert(getInductionDescriptor().getKind() ==
             InductionDescriptor::IK_PtrInduction &&
         "Not a pointer induction according to InductionDescriptor!");
  assert(cast<PHINode>(getUnderlyingInstr())->getType()->isPointerTy() &&
         "Unexpected type.");
  assert(!onlyScalarsGenerated(State.VF.isScalable()) &&
         "Recipe should have been replaced");
 
  unsigned CurrentPart = getUnrollPart(*this);
 
  // Build a pointer phi
  Value *ScalarStartValue = getStartValue()->getLiveInIRValue();
  Type *ScStValueType = ScalarStartValue->getType();
 
  BasicBlock *VectorPH = State.CFG.getPreheaderBBFor(this);
  PHINode *NewPointerPhi = nullptr;
  if (CurrentPart == 0) {
    auto *IVR = cast<VPHeaderPHIRecipe>(&getParent()
                                             ->getPlan()
                                             ->getVectorLoopRegion()
                                             ->getEntryBasicBlock()
                                             ->front());
    PHINode *CanonicalIV = cast<PHINode>(State.get(IVR, /*IsScalar*/ true));
    NewPointerPhi = PHINode::Create(ScStValueType, 2, "pointer.phi",
                                    CanonicalIV->getIterator());
    NewPointerPhi->addIncoming(ScalarStartValue, VectorPH);
    NewPointerPhi->setDebugLoc(getDebugLoc());
  } else {
    // The recipe has been unrolled. In that case, fetch the single pointer phi
    // shared among all unrolled parts of the recipe.
    auto *GEP =
        cast<GetElementPtrInst>(State.get(getFirstUnrolledPartOperand()));
    NewPointerPhi = cast<PHINode>(GEP->getPointerOperand());
  }
 
  // A pointer induction, performed by using a gep
  BasicBlock::iterator InductionLoc = State.Builder.GetInsertPoint();
  Value *ScalarStepValue = State.get(getStepValue(), VPLane(0));
  Type *PhiType = State.TypeAnalysis.inferScalarType(getStepValue());
  Value *RuntimeVF = getRuntimeVF(State.Builder, PhiType, State.VF);
  // Add induction update using an incorrect block temporarily. The phi node
  // will be fixed after VPlan execution. Note that at this point the latch
  // block cannot be used, as it does not exist yet.
  // TODO: Model increment value in VPlan, by turning the recipe into a
  // multi-def and a subclass of VPHeaderPHIRecipe.
  if (CurrentPart == 0) {
    // The recipe represents the first part of the pointer induction. Create the
    // GEP to increment the phi across all unrolled parts.
    unsigned UF = CurrentPart == 0 ? getParent()->getPlan()->getUF() : 1;
    Value *NumUnrolledElems =
        State.Builder.CreateMul(RuntimeVF, ConstantInt::get(PhiType, UF));
 
    Value *InductionGEP = GetElementPtrInst::Create(
        State.Builder.getInt8Ty(), NewPointerPhi,
        State.Builder.CreateMul(ScalarStepValue, NumUnrolledElems), "ptr.ind",
        InductionLoc);
 
    NewPointerPhi->addIncoming(InductionGEP, VectorPH);
  }
 
  // Create actual address geps that use the pointer phi as base and a
  // vectorized version of the step value (<step*0, ..., step*N>) as offset.
  Type *VecPhiType = VectorType::get(PhiType, State.VF);
  Value *StartOffsetScalar = State.Builder.CreateMul(
      RuntimeVF, ConstantInt::get(PhiType, CurrentPart));
  Value *StartOffset =
      State.Builder.CreateVectorSplat(State.VF, StartOffsetScalar);
  // Create a vector of consecutive numbers from zero to VF.
  StartOffset = State.Builder.CreateAdd(
      StartOffset, State.Builder.CreateStepVector(VecPhiType));
 
  assert(ScalarStepValue == State.get(getOperand(1), VPLane(0)) &&
         "scalar step must be the same across all parts");
  Value *GEP = State.Builder.CreateGEP(
      State.Builder.getInt8Ty(), NewPointerPhi,
      State.Builder.CreateMul(StartOffset, State.Builder.CreateVectorSplat(
                                               State.VF, ScalarStepValue)),
      "vector.gep");
  State.set(this, GEP);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPWidenPointerInductionRecipe::print(raw_ostream &O, const Twine &Indent,
                                          VPSlotTracker &SlotTracker) const {
  assert((getNumOperands() == 2 || getNumOperands() == 4) &&
         "unexpected number of operands");
  O << Indent << "EMIT ";
  printAsOperand(O, SlotTracker);
  O << " = WIDEN-POINTER-INDUCTION ";
  getStartValue()->printAsOperand(O, SlotTracker);
  O << ", ";
  getStepValue()->printAsOperand(O, SlotTracker);
  if (getNumOperands() == 4) {
    O << ", ";
    getOperand(2)->printAsOperand(O, SlotTracker);
    O << ", ";
    getOperand(3)->printAsOperand(O, SlotTracker);
  }
}
#endif
 
void VPExpandSCEVRecipe::execute(VPTransformState &State) {
  assert(!State.Lane && "cannot be used in per-lane");
  if (State.ExpandedSCEVs.contains(Expr)) {
    // SCEV Expr has already been expanded, result must already be set. At the
    // moment we have to execute the entry block twice (once before skeleton
    // creation to get expanded SCEVs used by the skeleton and once during
    // regular VPlan execution).
    State.Builder.SetInsertPoint(State.CFG.VPBB2IRBB[getParent()]);
    assert(State.get(this, VPLane(0)) == State.ExpandedSCEVs[Expr] &&
           "Results must match");
    return;
  }
 
  const DataLayout &DL = State.CFG.PrevBB->getDataLayout();
  SCEVExpander Exp(SE, DL, "induction");
 
  Value *Res = Exp.expandCodeFor(Expr, Expr->getType(),
                                 &*State.Builder.GetInsertPoint());
  State.ExpandedSCEVs[Expr] = Res;
  State.set(this, Res, VPLane(0));
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPExpandSCEVRecipe::print(raw_ostream &O, const Twine &Indent,
                               VPSlotTracker &SlotTracker) const {
  O << Indent << "EMIT ";
  printAsOperand(O, SlotTracker);
  O << " = EXPAND SCEV " << *Expr;
}
#endif
 
void VPWidenCanonicalIVRecipe::execute(VPTransformState &State) {
  Value *CanonicalIV = State.get(getOperand(0), /*IsScalar*/ true);
  Type *STy = CanonicalIV->getType();
  IRBuilder<> Builder(State.CFG.PrevBB->getTerminator());
  ElementCount VF = State.VF;
  Value *VStart = VF.isScalar()
                      ? CanonicalIV
                      : Builder.CreateVectorSplat(VF, CanonicalIV, "broadcast");
  Value *VStep = createStepForVF(Builder, STy, VF, getUnrollPart(*this));
  if (VF.isVector()) {
    VStep = Builder.CreateVectorSplat(VF, VStep);
    VStep =
        Builder.CreateAdd(VStep, Builder.CreateStepVector(VStep->getType()));
  }
  Value *CanonicalVectorIV = Builder.CreateAdd(VStart, VStep, "vec.iv");
  State.set(this, CanonicalVectorIV);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPWidenCanonicalIVRecipe::print(raw_ostream &O, const Twine &Indent,
                                     VPSlotTracker &SlotTracker) const {
  O << Indent << "EMIT ";
  printAsOperand(O, SlotTracker);
  O << " = WIDEN-CANONICAL-INDUCTION ";
  printOperands(O, SlotTracker);
}
#endif
 
void VPFirstOrderRecurrencePHIRecipe::execute(VPTransformState &State) {
  auto &Builder = State.Builder;
  // Create a vector from the initial value.
  auto *VectorInit = getStartValue()->getLiveInIRValue();
 
  Type *VecTy = State.VF.isScalar()
                    ? VectorInit->getType()
                    : VectorType::get(VectorInit->getType(), State.VF);
 
  BasicBlock *VectorPH = State.CFG.getPreheaderBBFor(this);
  if (State.VF.isVector()) {
    auto *IdxTy = Builder.getInt32Ty();
    auto *One = ConstantInt::get(IdxTy, 1);
    IRBuilder<>::InsertPointGuard Guard(Builder);
    Builder.SetInsertPoint(VectorPH->getTerminator());
    auto *RuntimeVF = getRuntimeVF(Builder, IdxTy, State.VF);
    auto *LastIdx = Builder.CreateSub(RuntimeVF, One);
    VectorInit = Builder.CreateInsertElement(
        PoisonValue::get(VecTy), VectorInit, LastIdx, "vector.recur.init");
  }
 
  // Create a phi node for the new recurrence.
  PHINode *Phi = PHINode::Create(VecTy, 2, "vector.recur");
  Phi->insertBefore(State.CFG.PrevBB->getFirstInsertionPt());
  Phi->addIncoming(VectorInit, VectorPH);
  State.set(this, Phi);
}
 
InstructionCost
VPFirstOrderRecurrencePHIRecipe::computeCost(ElementCount VF,
                                             VPCostContext &Ctx) const {
  TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
  if (VF.isScalar())
  return Ctx.TTI.getCFInstrCost(Instruction::PHI, CostKind);
 
  if (VF.isScalable() && VF.getKnownMinValue() == 1)
    return InstructionCost::getInvalid();
 
  SmallVector<int> Mask(VF.getKnownMinValue());
  std::iota(Mask.begin(), Mask.end(), VF.getKnownMinValue() - 1);
  Type *VectorTy =
      toVectorTy(Ctx.Types.inferScalarType(this->getVPSingleValue()), VF);
 
  return Ctx.TTI.getShuffleCost(TargetTransformInfo::SK_Splice,
                                cast<VectorType>(VectorTy), Mask, CostKind,
                                VF.getKnownMinValue() - 1);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPFirstOrderRecurrencePHIRecipe::print(raw_ostream &O, const Twine &Indent,
                                            VPSlotTracker &SlotTracker) const {
  O << Indent << "FIRST-ORDER-RECURRENCE-PHI ";
  printAsOperand(O, SlotTracker);
  O << " = phi ";
  printOperands(O, SlotTracker);
}
#endif
 
void VPReductionPHIRecipe::execute(VPTransformState &State) {
  auto &Builder = State.Builder;
 
  // Reductions do not have to start at zero. They can start with
  // any loop invariant values.
  VPValue *StartVPV = getStartValue();
  Value *StartV = StartVPV->getLiveInIRValue();
 
  // In order to support recurrences we need to be able to vectorize Phi nodes.
  // Phi nodes have cycles, so we need to vectorize them in two stages. This is
  // stage #1: We create a new vector PHI node with no incoming edges. We'll use
  // this value when we vectorize all of the instructions that use the PHI.
  bool ScalarPHI = State.VF.isScalar() || IsInLoop;
  Type *VecTy = ScalarPHI ? StartV->getType()
                          : VectorType::get(StartV->getType(), State.VF);
 
  BasicBlock *HeaderBB = State.CFG.PrevBB;
  assert(State.CurrentParentLoop->getHeader() == HeaderBB &&
         "recipe must be in the vector loop header");
  auto *Phi = PHINode::Create(VecTy, 2, "vec.phi");
  Phi->insertBefore(HeaderBB->getFirstInsertionPt());
  State.set(this, Phi, IsInLoop);
 
  BasicBlock *VectorPH = State.CFG.getPreheaderBBFor(this);
 
  Value *Iden = nullptr;
  RecurKind RK = RdxDesc.getRecurrenceKind();
  unsigned CurrentPart = getUnrollPart(*this);
 
  if (RecurrenceDescriptor::isMinMaxRecurrenceKind(RK) ||
      RecurrenceDescriptor::isAnyOfRecurrenceKind(RK)) {
    // MinMax and AnyOf reductions have the start value as their identity.
    if (ScalarPHI) {
      Iden = StartV;
    } else {
      IRBuilderBase::InsertPointGuard IPBuilder(Builder);
      Builder.SetInsertPoint(VectorPH->getTerminator());
      StartV = Iden = State.get(StartVPV);
    }
  } else if (RecurrenceDescriptor::isFindLastIVRecurrenceKind(RK)) {
    // [I|F]FindLastIV will use a sentinel value to initialize the reduction
    // phi or the resume value from the main vector loop when vectorizing the
    // epilogue loop. In the exit block, ComputeReductionResult will generate
    // checks to verify if the reduction result is the sentinel value. If the
    // result is the sentinel value, it will be corrected back to the start
    // value.
    // TODO: The sentinel value is not always necessary. When the start value is
    // a constant, and smaller than the start value of the induction variable,
    // the start value can be directly used to initialize the reduction phi.
    Iden = StartV;
    if (!ScalarPHI) {
      IRBuilderBase::InsertPointGuard IPBuilder(Builder);
      Builder.SetInsertPoint(VectorPH->getTerminator());
      StartV = Iden = Builder.CreateVectorSplat(State.VF, Iden);
    }
  } else {
    Iden = llvm::getRecurrenceIdentity(RK, VecTy->getScalarType(),
                                       RdxDesc.getFastMathFlags());
 
    if (!ScalarPHI) {
      if (CurrentPart == 0) {
        // Create start and identity vector values for the reduction in the
        // preheader.
        // TODO: Introduce recipes in VPlan preheader to create initial values.
        Iden = Builder.CreateVectorSplat(State.VF, Iden);
        IRBuilderBase::InsertPointGuard IPBuilder(Builder);
        Builder.SetInsertPoint(VectorPH->getTerminator());
        Constant *Zero = Builder.getInt32(0);
        StartV = Builder.CreateInsertElement(Iden, StartV, Zero);
      } else {
        Iden = Builder.CreateVectorSplat(State.VF, Iden);
      }
    }
  }
 
  Phi = cast<PHINode>(State.get(this, IsInLoop));
  Value *StartVal = (CurrentPart == 0) ? StartV : Iden;
  Phi->addIncoming(StartVal, VectorPH);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPReductionPHIRecipe::print(raw_ostream &O, const Twine &Indent,
                                 VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN-REDUCTION-PHI ";
 
  printAsOperand(O, SlotTracker);
  O << " = phi ";
  printOperands(O, SlotTracker);
}
#endif
 
void VPWidenPHIRecipe::execute(VPTransformState &State) {
  assert(EnableVPlanNativePath &&
         "Non-native vplans are not expected to have VPWidenPHIRecipes.");
 
  Value *Op0 = State.get(getOperand(0));
  Type *VecTy = Op0->getType();
  Value *VecPhi = State.Builder.CreatePHI(VecTy, 2, "vec.phi");
  State.set(this, VecPhi);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPWidenPHIRecipe::print(raw_ostream &O, const Twine &Indent,
                             VPSlotTracker &SlotTracker) const {
  O << Indent << "WIDEN-PHI ";
 
  auto *OriginalPhi = cast<PHINode>(getUnderlyingValue());
  // Unless all incoming values are modeled in VPlan  print the original PHI
  // directly.
  // TODO: Remove once all VPWidenPHIRecipe instances keep all relevant incoming
  // values as VPValues.
  if (getNumOperands() != OriginalPhi->getNumOperands()) {
    O << VPlanIngredient(OriginalPhi);
    return;
  }
 
  printAsOperand(O, SlotTracker);
  O << " = phi ";
  printOperands(O, SlotTracker);
}
#endif
 
// TODO: It would be good to use the existing VPWidenPHIRecipe instead and
// remove VPActiveLaneMaskPHIRecipe.
void VPActiveLaneMaskPHIRecipe::execute(VPTransformState &State) {
  BasicBlock *VectorPH = State.CFG.getPreheaderBBFor(this);
  Value *StartMask = State.get(getOperand(0));
  PHINode *Phi =
      State.Builder.CreatePHI(StartMask->getType(), 2, "active.lane.mask");
  Phi->addIncoming(StartMask, VectorPH);
  Phi->setDebugLoc(getDebugLoc());
  State.set(this, Phi);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPActiveLaneMaskPHIRecipe::print(raw_ostream &O, const Twine &Indent,
                                      VPSlotTracker &SlotTracker) const {
  O << Indent << "ACTIVE-LANE-MASK-PHI ";
 
  printAsOperand(O, SlotTracker);
  O << " = phi ";
  printOperands(O, SlotTracker);
}
#endif
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPEVLBasedIVPHIRecipe::print(raw_ostream &O, const Twine &Indent,
                                  VPSlotTracker &SlotTracker) const {
  O << Indent << "EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI ";
 
  printAsOperand(O, SlotTracker);
  O << " = phi ";
  printOperands(O, SlotTracker);
}
#endif
 
void VPScalarPHIRecipe::execute(VPTransformState &State) {
  BasicBlock *VectorPH = State.CFG.getPreheaderBBFor(this);
  Value *Start = State.get(getStartValue(), VPLane(0));
  PHINode *Phi = State.Builder.CreatePHI(Start->getType(), 2, Name);
  Phi->addIncoming(Start, VectorPH);
  Phi->setDebugLoc(getDebugLoc());
  State.set(this, Phi, /*IsScalar=*/true);
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPScalarPHIRecipe::print(raw_ostream &O, const Twine &Indent,
                              VPSlotTracker &SlotTracker) const {
  O << Indent << "SCALAR-PHI ";
  printAsOperand(O, SlotTracker);
  O << " = phi ";
  printOperands(O, SlotTracker);
}
#endif