TargetTransformInfo.h

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//===- TargetTransformInfo.h ------------------------------------*- C++ -*-===//
//
// 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 pass exposes codegen information to IR-level passes. Every
/// transformation that uses codegen information is broken into three parts:
/// 1. The IR-level analysis pass.
/// 2. The IR-level transformation interface which provides the needed
///    information.
/// 3. Codegen-level implementation which uses target-specific hooks.
///
/// This file defines #2, which is the interface that IR-level transformations
/// use for querying the codegen.
///
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_ANALYSIS_TARGETTRANSFORMINFO_H
#define LLVM_ANALYSIS_TARGETTRANSFORMINFO_H
 
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/BitmaskEnum.h"
#include "llvm/ADT/STLFunctionalExtras.h"
#include "llvm/ADT/Uniformity.h"
#include "llvm/Analysis/IVDescriptors.h"
#include "llvm/Analysis/InterestingMemoryOperand.h"
#include "llvm/IR/FMF.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
#include "llvm/Support/AtomicOrdering.h"
#include "llvm/Support/BranchProbability.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/InstructionCost.h"
#include <functional>
#include <optional>
#include <utility>
 
namespace llvm {
 
namespace Intrinsic {
typedef unsigned ID;
}
 
class AllocaInst;
class AssumptionCache;
class BlockFrequencyInfo;
class DominatorTree;
class CondBrInst;
class Function;
class GlobalValue;
class InstCombiner;
class OptimizationRemarkEmitter;
class InterleavedAccessInfo;
class ICmpInst;
class IntrinsicInst;
class LoadInst;
class Loop;
class LoopInfo;
class LoopVectorizationLegality;
class ProfileSummaryInfo;
class RecurrenceDescriptor;
class SCEV;
class ScalarEvolution;
class SmallBitVector;
class StoreInst;
class SwitchInst;
class TargetLibraryInfo;
class Type;
class VPIntrinsic;
struct KnownBits;
 
/// Information about a load/store intrinsic defined by the target.
struct MemIntrinsicInfo {
  /// This is the pointer that the intrinsic is loading from or storing to.
  /// If this is non-null, then analysis/optimization passes can assume that
  /// this intrinsic is functionally equivalent to a load/store from this
  /// pointer.
  Value *PtrVal = nullptr;
 
  // Ordering for atomic operations.
  AtomicOrdering Ordering = AtomicOrdering::NotAtomic;
 
  // Same Id is set by the target for corresponding load/store intrinsics.
  unsigned short MatchingId = 0;
 
  bool ReadMem = false;
  bool WriteMem = false;
  bool IsVolatile = false;
 
  SmallVector<InterestingMemoryOperand, 1> InterestingOperands;
 
  bool isUnordered() const {
    return (Ordering == AtomicOrdering::NotAtomic ||
            Ordering == AtomicOrdering::Unordered) &&
           !IsVolatile;
  }
};
 
/// Attributes of a target dependent hardware loop.
struct HardwareLoopInfo {
  HardwareLoopInfo() = delete;
  LLVM_ABI HardwareLoopInfo(Loop *L);
  Loop *L = nullptr;
  BasicBlock *ExitBlock = nullptr;
  CondBrInst *ExitBranch = nullptr;
  const SCEV *ExitCount = nullptr;
  IntegerType *CountType = nullptr;
  Value *LoopDecrement = nullptr; // Decrement the loop counter by this
                                  // value in every iteration.
  bool IsNestingLegal = false;    // Can a hardware loop be a parent to
                                  // another hardware loop?
  bool CounterInReg = false;      // Should loop counter be updated in
                                  // the loop via a phi?
  bool PerformEntryTest = false;  // Generate the intrinsic which also performs
                                  // icmp ne zero on the loop counter value and
                                  // produces an i1 to guard the loop entry.
  LLVM_ABI bool isHardwareLoopCandidate(ScalarEvolution &SE, LoopInfo &LI,
                                        DominatorTree &DT,
                                        bool ForceNestedLoop = false,
                                        bool ForceHardwareLoopPHI = false);
  LLVM_ABI bool canAnalyze(LoopInfo &LI);
};
 
/// Information for memory intrinsic cost model.
class MemIntrinsicCostAttributes {
  /// Optional context instruction, if one exists, e.g. the
  /// load/store to transform to the intrinsic.
  const Instruction *I = nullptr;
 
  /// Address in memory.
  const Value *Ptr = nullptr;
 
  /// Vector type of the data to be loaded or stored.
  Type *DataTy = nullptr;
 
  /// ID of the memory intrinsic.
  Intrinsic::ID IID;
 
  /// True when the memory access is predicated with a mask
  /// that is not a compile-time constant.
  bool VariableMask = true;
 
  /// Address space of the pointer.
  unsigned AddressSpace = 0;
 
  /// Alignment of single element.
  Align Alignment;
 
  const Value *StrideVal;
 
public:
  MemIntrinsicCostAttributes(Intrinsic::ID Id, Type *DataTy, const Value *Ptr,
                             bool VariableMask, Align Alignment,
                             const Instruction *I = nullptr,
                             const Value *StrideVal = nullptr)
 
      : I(I), Ptr(Ptr), DataTy(DataTy), IID(Id), VariableMask(VariableMask),
        Alignment(Alignment), StrideVal(StrideVal) {}
 
  MemIntrinsicCostAttributes(Intrinsic::ID Id, Type *DataTy, Align Alignment,
                             unsigned AddressSpace = 0,
                             const Value *StrideVal = nullptr)
      : DataTy(DataTy), IID(Id), AddressSpace(AddressSpace),
        Alignment(Alignment), StrideVal(StrideVal) {}
 
  MemIntrinsicCostAttributes(Intrinsic::ID Id, Type *DataTy, bool VariableMask,
                             Align Alignment, const Instruction *I = nullptr,
                             const Value *StrideVal = nullptr)
 
      : I(I), DataTy(DataTy), IID(Id), VariableMask(VariableMask),
        Alignment(Alignment), StrideVal(StrideVal) {}
 
  Intrinsic::ID getID() const { return IID; }
  const Instruction *getInst() const { return I; }
  const Value *getPointer() const { return Ptr; }
  Type *getDataType() const { return DataTy; }
  bool getVariableMask() const { return VariableMask; }
  unsigned getAddressSpace() const { return AddressSpace; }
  Align getAlignment() const { return Alignment; }
  const Value *getStrideVal() const { return StrideVal; }
};
 
/// Represents a hint about the context in which a vector instruction or
/// intrinsic is used.
///
/// On some targets, inserts/extracts can cheaply be folded into loads/stores.
/// Similarly, vp.merge can also be folded into binary ops on some targets.
///
/// This enum allows the vectorizer to give getVectorInstrCost and
/// getIntrinsicInstrCost an idea of how the values are used.
///
/// See \c getVectorInstrContextHint to compute a VectorInstrContext from an
/// insert/extract Instruction*.
enum class VectorInstrContext : uint8_t {
  None,  ///< The instruction is not folded.
  Load,  ///< The value being inserted comes from a load (InsertElement only).
  Store, ///< The extracted value is stored (ExtractElement only).
  BinaryOp,      ///< One of the operands is a binary op.
  SplatOpFolded, ///< All of the value's users support splatting the value.
};
 
class IntrinsicCostAttributes {
  const IntrinsicInst *II = nullptr;
  Type *RetTy = nullptr;
  Intrinsic::ID IID;
  SmallVector<Type *, 4> ParamTys;
  SmallVector<const Value *, 4> Arguments;
  FastMathFlags FMF;
  // If ScalarizationCost is UINT_MAX, the cost of scalarizing the
  // arguments and the return value will be computed based on types.
  InstructionCost ScalarizationCost = InstructionCost::getInvalid();
  VectorInstrContext VIC = VectorInstrContext::None;
 
public:
  LLVM_ABI IntrinsicCostAttributes(
      Intrinsic::ID Id, const CallBase &CI,
      InstructionCost ScalarCost = InstructionCost::getInvalid(),
      bool TypeBasedOnly = false);
 
  LLVM_ABI IntrinsicCostAttributes(
      Intrinsic::ID Id, Type *RTy, ArrayRef<Type *> Tys,
      FastMathFlags Flags = FastMathFlags(), const IntrinsicInst *I = nullptr,
      InstructionCost ScalarCost = InstructionCost::getInvalid());
 
  LLVM_ABI IntrinsicCostAttributes(Intrinsic::ID Id, Type *RTy,
                                   ArrayRef<const Value *> Args);
 
  LLVM_ABI IntrinsicCostAttributes(
      Intrinsic::ID Id, Type *RTy, ArrayRef<const Value *> Args,
      ArrayRef<Type *> Tys, FastMathFlags Flags = FastMathFlags(),
      const IntrinsicInst *I = nullptr,
      InstructionCost ScalarCost = InstructionCost::getInvalid(),
      VectorInstrContext VIC = VectorInstrContext::None);
 
  Intrinsic::ID getID() const { return IID; }
  const IntrinsicInst *getInst() const { return II; }
  Type *getReturnType() const { return RetTy; }
  FastMathFlags getFlags() const { return FMF; }
  InstructionCost getScalarizationCost() const { return ScalarizationCost; }
  VectorInstrContext getVectorInstrContext() const { return VIC; }
  const SmallVectorImpl<const Value *> &getArgs() const { return Arguments; }
  const SmallVectorImpl<Type *> &getArgTypes() const { return ParamTys; }
 
  bool isTypeBasedOnly() const {
    return Arguments.empty();
  }
 
  bool skipScalarizationCost() const { return ScalarizationCost.isValid(); }
};
 
enum class TailFoldingStyle {
  /// Don't use tail folding
  None,
  /// Use predicate only to mask operations on data in the loop.
  /// When the VL is not known to be a power-of-2, this method requires a
  /// runtime overflow check for the i + VL in the loop because it compares the
  /// scalar induction variable against the tripcount rounded up by VL which may
  /// overflow. When the VL is a power-of-2, both the increment and uprounded
  /// tripcount will overflow to 0, which does not require a runtime check
  /// since the loop is exited when the loop induction variable equals the
  /// uprounded trip-count, which are both 0.
  Data,
  /// Same as Data, but avoids using the get.active.lane.mask intrinsic to
  /// calculate the mask and instead implements this with a
  /// splat/stepvector/cmp.
  /// FIXME: Can this kind be removed now that SelectionDAGBuilder expands the
  /// active.lane.mask intrinsic when it is not natively supported?
  DataWithoutLaneMask,
  /// Use predicate to control both data and control flow.
  /// This method always requires a runtime overflow check for the i + VL
  /// increment inside the loop, because it uses the result direclty in the
  /// active.lane.mask to calculate the mask for the next iteration. If the
  /// increment overflows, the mask is no longer correct.
  DataAndControlFlow,
  /// Use predicated EVL instructions for tail-folding.
  /// Indicates that VP intrinsics should be used.
  DataWithEVL,
};
 
struct TailFoldingInfo {
  TargetLibraryInfo *TLI;
  LoopVectorizationLegality *LVL;
  InterleavedAccessInfo *IAI;
  TailFoldingInfo(TargetLibraryInfo *TLI, LoopVectorizationLegality *LVL,
                  InterleavedAccessInfo *IAI)
      : TLI(TLI), LVL(LVL), IAI(IAI) {}
};
 
class TargetTransformInfo;
typedef TargetTransformInfo TTI;
class TargetTransformInfoImplBase;
 
/// This pass provides access to the codegen interfaces that are needed
/// for IR-level transformations.
class TargetTransformInfo {
public:
  enum PartialReductionExtendKind {
    PR_None,
    PR_SignExtend,
    PR_ZeroExtend,
    PR_FPExtend
  };
 
  /// Get the kind of extension that an instruction represents.
  LLVM_ABI static PartialReductionExtendKind
  getPartialReductionExtendKind(Instruction *I);
  /// Get the kind of extension that a cast opcode represents.
  LLVM_ABI static PartialReductionExtendKind
  getPartialReductionExtendKind(Instruction::CastOps CastOpc);
  /// Get the cast opcode for an extension kind.
  LLVM_ABI static Instruction::CastOps
  getOpcodeForPartialReductionExtendKind(PartialReductionExtendKind Kind);
 
  /// Construct a TTI object using a type implementing the \c Concept
  /// API below.
  ///
  /// This is used by targets to construct a TTI wrapping their target-specific
  /// implementation that encodes appropriate costs for their target.
  LLVM_ABI explicit TargetTransformInfo(
      std::unique_ptr<const TargetTransformInfoImplBase> Impl);
 
  /// Construct a baseline TTI object using a minimal implementation of
  /// the \c Concept API below.
  ///
  /// The TTI implementation will reflect the information in the DataLayout
  /// provided if non-null.
  LLVM_ABI explicit TargetTransformInfo(const DataLayout &DL);
 
  // Provide move semantics.
  LLVM_ABI TargetTransformInfo(TargetTransformInfo &&Arg);
  LLVM_ABI TargetTransformInfo &operator=(TargetTransformInfo &&RHS);
 
  // We need to define the destructor out-of-line to define our sub-classes
  // out-of-line.
  LLVM_ABI ~TargetTransformInfo();
 
  /// Handle the invalidation of this information.
  ///
  /// When used as a result of \c TargetIRAnalysis this method will be called
  /// when the function this was computed for changes. When it returns false,
  /// the information is preserved across those changes.
  bool invalidate(Function &, const PreservedAnalyses &,
                  FunctionAnalysisManager::Invalidator &) {
    // FIXME: We should probably in some way ensure that the subtarget
    // information for a function hasn't changed.
    return false;
  }
 
  /// \name Generic Target Information
  /// @{
 
  /// The kind of cost model.
  ///
  /// There are several different cost models that can be customized by the
  /// target. The normalization of each cost model may be target specific.
  /// e.g. TCK_SizeAndLatency should be comparable to target thresholds such as
  /// those derived from MCSchedModel::LoopMicroOpBufferSize etc.
  enum TargetCostKind {
    TCK_RecipThroughput, ///< Reciprocal throughput.
    TCK_Latency,         ///< The latency of instruction.
    TCK_CodeSize,        ///< Instruction code size.
    TCK_SizeAndLatency   ///< The weighted sum of size and latency.
  };
 
  /// Underlying constants for 'cost' values in this interface.
  ///
  /// Many APIs in this interface return a cost. This enum defines the
  /// fundamental values that should be used to interpret (and produce) those
  /// costs. The costs are returned as an int rather than a member of this
  /// enumeration because it is expected that the cost of one IR instruction
  /// may have a multiplicative factor to it or otherwise won't fit directly
  /// into the enum. Moreover, it is common to sum or average costs which works
  /// better as simple integral values. Thus this enum only provides constants.
  /// Also note that the returned costs are signed integers to make it natural
  /// to add, subtract, and test with zero (a common boundary condition). It is
  /// not expected that 2^32 is a realistic cost to be modeling at any point.
  ///
  /// Note that these costs should usually reflect the intersection of code-size
  /// cost and execution cost. A free instruction is typically one that folds
  /// into another instruction. For example, reg-to-reg moves can often be
  /// skipped by renaming the registers in the CPU, but they still are encoded
  /// and thus wouldn't be considered 'free' here.
  enum TargetCostConstants {
    TCC_Free = 0,     ///< Expected to fold away in lowering.
    TCC_Basic = 1,    ///< The cost of a typical 'add' instruction.
    TCC_Expensive = 4 ///< The cost of a 'div' instruction on x86.
  };
 
  /// Estimate the cost of a GEP operation when lowered.
  ///
  /// \p PointeeType is the source element type of the GEP.
  /// \p Ptr is the base pointer operand.
  /// \p Operands is the list of indices following the base pointer.
  ///
  /// \p AccessType is a hint as to what type of memory might be accessed by
  /// users of the GEP. getGEPCost will use it to determine if the GEP can be
  /// folded into the addressing mode of a load/store. If AccessType is null,
  /// then the resulting target type based off of PointeeType will be used as an
  /// approximation.
  LLVM_ABI InstructionCost getGEPCost(Type *PointeeType, const Value *Ptr,
                                      ArrayRef<const Value *> Operands,
                                      TargetCostKind CostKind,
                                      Type *AccessType = nullptr) const;
 
  /// Describe known properties for a set of pointers.
  struct PointersChainInfo {
    /// All the GEPs in a set have same base address.
    unsigned IsSameBaseAddress : 1;
    /// These properties only valid if SameBaseAddress is set.
    /// True if all pointers are separated by a unit stride.
    unsigned IsUnitStride : 1;
    /// True if distance between any two neigbouring pointers is a known value.
    unsigned IsKnownStride : 1;
    unsigned Reserved : 29;
 
    bool isSameBase() const { return IsSameBaseAddress; }
    bool isUnitStride() const { return IsSameBaseAddress && IsUnitStride; }
    bool isKnownStride() const { return IsSameBaseAddress && IsKnownStride; }
 
    static PointersChainInfo getUnitStride() {
      return {/*IsSameBaseAddress=*/1, /*IsUnitStride=*/1,
              /*IsKnownStride=*/1, 0};
    }
    static PointersChainInfo getKnownStride() {
      return {/*IsSameBaseAddress=*/1, /*IsUnitStride=*/0,
              /*IsKnownStride=*/1, 0};
    }
    static PointersChainInfo getUnknownStride() {
      return {/*IsSameBaseAddress=*/1, /*IsUnitStride=*/0,
              /*IsKnownStride=*/0, 0};
    }
  };
  static_assert(sizeof(PointersChainInfo) == 4, "Was size increase justified?");
 
  /// Estimate the cost of a chain of pointers (typically pointer operands of a
  /// chain of loads or stores within same block) operations set when lowered.
  /// \p AccessTy is the type of the loads/stores that will ultimately use the
  /// \p Ptrs.
  LLVM_ABI InstructionCost
  getPointersChainCost(ArrayRef<const Value *> Ptrs, const Value *Base,
                       const PointersChainInfo &Info, Type *AccessTy,
                       const TargetCostKind CostKind) const;
 
  /// \returns A value by which our inlining threshold should be multiplied.
  /// This is primarily used to bump up the inlining threshold wholesale on
  /// targets where calls are unusually expensive.
  ///
  /// TODO: This is a rather blunt instrument.  Perhaps altering the costs of
  /// individual classes of instructions would be better.
  LLVM_ABI unsigned getInliningThresholdMultiplier() const;
 
  LLVM_ABI unsigned getInliningCostBenefitAnalysisSavingsMultiplier() const;
  LLVM_ABI unsigned getInliningCostBenefitAnalysisProfitableMultiplier() const;
 
  /// \returns The bonus of inlining the last call to a static function.
  LLVM_ABI int getInliningLastCallToStaticBonus() const;
 
  /// \returns A value to be added to the inlining threshold.
  LLVM_ABI unsigned adjustInliningThreshold(const CallBase *CB) const;
 
  /// \returns The cost of having an Alloca in the caller if not inlined, to be
  /// added to the threshold
  LLVM_ABI unsigned getCallerAllocaCost(const CallBase *CB,
                                        const AllocaInst *AI) const;
 
  /// \returns Vector bonus in percent.
  ///
  /// Vector bonuses: We want to more aggressively inline vector-dense kernels
  /// and apply this bonus based on the percentage of vector instructions. A
  /// bonus is applied if the vector instructions exceed 50% and half that
  /// amount is applied if it exceeds 10%. Note that these bonuses are some what
  /// arbitrary and evolved over time by accident as much as because they are
  /// principled bonuses.
  /// FIXME: It would be nice to base the bonus values on something more
  /// scientific. A target may has no bonus on vector instructions.
  LLVM_ABI int getInlinerVectorBonusPercent() const;
 
  /// \return the expected cost of a memcpy, which could e.g. depend on the
  /// source/destination type and alignment and the number of bytes copied.
  LLVM_ABI InstructionCost getMemcpyCost(const Instruction *I) const;
 
  /// Returns the maximum memset / memcpy size in bytes that still makes it
  /// profitable to inline the call.
  LLVM_ABI uint64_t getMaxMemIntrinsicInlineSizeThreshold() const;
 
  /// Returns the maximum length in bytes for which a memset with a
  /// non-constant length, known to be bounded by that value, is preferably
  /// expanded inline instead of calling the library. Zero disables the
  /// expansion.
  LLVM_ABI uint64_t getMaxBoundedMemSetInlineSize() const;
 
  /// \return The estimated number of case clusters when lowering \p 'SI'.
  /// \p JTSize Set a jump table size only when \p SI is suitable for a jump
  /// table.
  LLVM_ABI unsigned
  getEstimatedNumberOfCaseClusters(const SwitchInst &SI, unsigned &JTSize,
                                   ProfileSummaryInfo *PSI,
                                   BlockFrequencyInfo *BFI) const;
 
  /// Estimate the cost of a given IR user when lowered.
  ///
  /// This can estimate the cost of either a ConstantExpr or Instruction when
  /// lowered.
  ///
  /// \p Operands is a list of operands which can be a result of transformations
  /// of the current operands. The number of the operands on the list must equal
  /// to the number of the current operands the IR user has. Their order on the
  /// list must be the same as the order of the current operands the IR user
  /// has.
  ///
  /// The returned cost is defined in terms of \c TargetCostConstants, see its
  /// comments for a detailed explanation of the cost values.
  LLVM_ABI InstructionCost getInstructionCost(const User *U,
                                              ArrayRef<const Value *> Operands,
                                              TargetCostKind CostKind) const;
 
  /// This is a helper function which calls the three-argument
  /// getInstructionCost with \p Operands which are the current operands U has.
  InstructionCost getInstructionCost(const User *U,
                                     TargetCostKind CostKind) const {
    SmallVector<const Value *, 4> Operands(U->operand_values());
    return getInstructionCost(U, Operands, CostKind);
  }
 
  /// If a branch or a select condition is skewed in one direction by more than
  /// this factor, it is very likely to be predicted correctly.
  LLVM_ABI BranchProbability getPredictableBranchThreshold() const;
 
  /// Returns estimated penalty of a branch misprediction in latency. Indicates
  /// how aggressive the target wants for eliminating unpredictable branches. A
  /// zero return value means extra optimization applied to them should be
  /// minimal.
  LLVM_ABI InstructionCost getBranchMispredictPenalty() const;
 
  /// Return true if branch divergence exists.
  ///
  /// Branch divergence has a significantly negative impact on GPU performance
  /// when threads in the same wavefront take different paths due to conditional
  /// branches.
  ///
  /// If \p F is passed, provides a context function. If \p F is known to only
  /// execute in a single threaded environment, the target may choose to skip
  /// uniformity analysis and assume all values are uniform.
  LLVM_ABI bool hasBranchDivergence(const Function *F = nullptr) const;
 
  /// Get target-specific uniformity information for a value.
  /// This allows targets to provide more fine-grained control over
  /// uniformity analysis by specifying whether specific values
  /// should always or never be considered uniform, or require custom
  /// operand-based analysis.
  /// \param V The value to query for uniformity information.
  /// \return ValueUniformity.
  LLVM_ABI ValueUniformity getValueUniformity(const Value *V) const;
 
  /// Query the target whether the specified address space cast from FromAS to
  /// ToAS is valid.
  LLVM_ABI bool isValidAddrSpaceCast(unsigned FromAS, unsigned ToAS) const;
 
  /// Return false if a \p AS0 address cannot possibly alias a \p AS1 address.
  LLVM_ABI bool addrspacesMayAlias(unsigned AS0, unsigned AS1) const;
 
  /// Returns the address space ID for a target's 'flat' address space. Note
  /// this is not necessarily the same as addrspace(0), which LLVM sometimes
  /// refers to as the generic address space. The flat address space is a
  /// generic address space that can be used access multiple segments of memory
  /// with different address spaces. Access of a memory location through a
  /// pointer with this address space is expected to be legal but slower
  /// compared to the same memory location accessed through a pointer with a
  /// different address space.
  //
  /// This is for targets with different pointer representations which can
  /// be converted with the addrspacecast instruction. If a pointer is converted
  /// to this address space, optimizations should attempt to replace the access
  /// with the source address space.
  ///
  /// \returns ~0u if the target does not have such a flat address space to
  /// optimize away.
  LLVM_ABI unsigned getFlatAddressSpace() const;
 
  /// Return the most specific common address space containing AS1 and AS2.
  /// AS1 and AS2 must be distinct, and pointers from both spaces must be
  /// convertible to the target's flat address space with addrspacecast.
  /// Pointers from either input space must be convertible to the result with
  /// addrspacecast. Return getFlatAddressSpace() if no more specific common
  /// address space is available.
  LLVM_ABI unsigned getAddressSpaceJoin(unsigned AS1, unsigned AS2) const;
 
  /// Return any intrinsic address operand indexes which may be rewritten if
  /// they use a flat address space pointer.
  ///
  /// \returns true if the intrinsic was handled.
  LLVM_ABI bool collectFlatAddressOperands(SmallVectorImpl<int> &OpIndexes,
                                           Intrinsic::ID IID) const;
 
  LLVM_ABI bool isNoopAddrSpaceCast(unsigned FromAS, unsigned ToAS) const;
 
  // Given an address space cast of the given pointer value, calculate the known
  // bits of the source pointer in the source addrspace and the destination
  // pointer in the destination addrspace.
  LLVM_ABI std::pair<KnownBits, KnownBits>
  computeKnownBitsAddrSpaceCast(unsigned ToAS, const Value &PtrOp) const;
 
  // Given an address space cast, calculate the known bits of the resulting ptr
  // in the destination addrspace using the known bits of the source pointer in
  // the source addrspace.
  LLVM_ABI KnownBits computeKnownBitsAddrSpaceCast(
      unsigned FromAS, unsigned ToAS, const KnownBits &FromPtrBits) const;
 
  /// Returns a mask indicating which bits of a pointer remain unchanged when
  /// casting between address spaces. The returned APInt has the same bit width
  /// as the source address space pointer size.
  ///
  /// Some targets allow certain bits of a pointer to change (e.g., the low
  /// bits within a page) while still preserving the address space. This mask
  /// identifies those bits that are guaranteed to be preserved. If the mask is
  /// all zeros, no bits are preserved and address space inference cannot be
  /// performed safely.
  ///
  /// For example, given:
  ///   %gp = addrspacecast ptr addrspace(2) %sp to ptr
  ///   %a = ptrtoint ptr %gp to i64
  ///   %b = xor i64 7, %a
  ///   %gp2 = inttoptr i64 %b to ptr
  ///   store i16 0, ptr %gp2, align 2
  /// if the target preserves the upper bits, `%gp2` can be safely replaced
  /// with `inttoptr i64 %b to ptr addrspace(2)`.
  LLVM_ABI APInt getAddrSpaceCastPreservedPtrMask(unsigned SrcAS,
                                                  unsigned DstAS) const;
 
  /// Return true if globals in this address space can have initializers other
  /// than `undef`.
  LLVM_ABI bool
  canHaveNonUndefGlobalInitializerInAddressSpace(unsigned AS) const;
 
  LLVM_ABI unsigned getAssumedAddrSpace(const Value *V) const;
 
  LLVM_ABI std::pair<const Value *, unsigned>
  getPredicatedAddrSpace(const Value *V) const;
 
  /// Rewrite intrinsic call \p II such that \p OldV will be replaced with \p
  /// NewV, which has a different address space. This should happen for every
  /// operand index that collectFlatAddressOperands returned for the intrinsic.
  /// \returns nullptr if the intrinsic was not handled. Otherwise, returns the
  /// new value (which may be the original \p II with modified operands).
  /// If a different value is returned, the caller replaces all uses of \p II
  /// and erases it, including any side effects of the original call.
  LLVM_ABI Value *rewriteIntrinsicWithAddressSpace(IntrinsicInst *II,
                                                   Value *OldV,
                                                   Value *NewV) const;
 
  /// Test whether calls to a function lower to actual program function
  /// calls.
  ///
  /// The idea is to test whether the program is likely to require a 'call'
  /// instruction or equivalent in order to call the given function.
  ///
  /// FIXME: It's not clear that this is a good or useful query API. Client's
  /// should probably move to simpler cost metrics using the above.
  /// Alternatively, we could split the cost interface into distinct code-size
  /// and execution-speed costs. This would allow modelling the core of this
  /// query more accurately as a call is a single small instruction, but
  /// incurs significant execution cost.
  LLVM_ABI bool isLoweredToCall(const Function *F) const;
 
  struct LSRCost {
    /// TODO: Some of these could be merged. Also, a lexical ordering
    /// isn't always optimal.
    unsigned Insns;
    unsigned NumRegs;
    unsigned AddRecCost;
    unsigned NumIVMuls;
    unsigned NumBaseAdds;
    unsigned ImmCost;
    unsigned SetupCost;
    unsigned ScaleCost;
    unsigned NumPrePostIndex;
  };
 
  /// Parameters that control the generic loop unrolling transformation.
  struct UnrollingPreferences {
    /// The cost threshold for the unrolled loop. Should be relative to the
    /// getInstructionCost values returned by this API, and the expectation is
    /// that the unrolled loop's instructions when run through that interface
    /// should not exceed this cost. However, this is only an estimate. Also,
    /// specific loops may be unrolled even with a cost above this threshold if
    /// deemed profitable. Set this to UINT_MAX to disable the loop body cost
    /// restriction.
    unsigned Threshold;
    /// If complete unrolling will reduce the cost of the loop, we will boost
    /// the Threshold by a certain percent to allow more aggressive complete
    /// unrolling. This value provides the maximum boost percentage that we
    /// can apply to Threshold (The value should be no less than 100).
    /// BoostedThreshold = Threshold * min(RolledCost / UnrolledCost,
    ///                                    MaxPercentThresholdBoost / 100)
    /// E.g. if complete unrolling reduces the loop execution time by 50%
    /// then we boost the threshold by the factor of 2x. If unrolling is not
    /// expected to reduce the running time, then we do not increase the
    /// threshold.
    unsigned MaxPercentThresholdBoost;
    /// The cost threshold for the unrolled loop when optimizing for size (set
    /// to UINT_MAX to disable).
    unsigned OptSizeThreshold;
    /// The cost threshold for the unrolled loop, like Threshold, but used
    /// for partial/runtime unrolling (set to UINT_MAX to disable).
    unsigned PartialThreshold;
    /// The cost threshold for the unrolled loop when optimizing for size, like
    /// OptSizeThreshold, but used for partial/runtime unrolling (set to
    /// UINT_MAX to disable).
    unsigned PartialOptSizeThreshold;
    /// Default unroll count for loops with run-time trip count.
    unsigned DefaultUnrollRuntimeCount;
    // Set the maximum unrolling factor. The unrolling factor may be selected
    // using the appropriate cost threshold, but may not exceed this number
    // (set to UINT_MAX to disable). This does not apply in cases where the
    // loop is being fully unrolled.
    unsigned MaxCount;
    /// Set the maximum upper bound of trip count. Allowing the MaxUpperBound
    /// to be overrided by a target gives more flexiblity on certain cases.
    /// By default, MaxUpperBound uses UnrollMaxUpperBound which value is 8.
    unsigned MaxUpperBound;
    /// Set the maximum unrolling factor for full unrolling. Like MaxCount, but
    /// applies even if full unrolling is selected. This allows a target to fall
    /// back to Partial unrolling if full unrolling is above FullUnrollMaxCount.
    unsigned FullUnrollMaxCount;
    // Represents number of instructions optimized when "back edge"
    // becomes "fall through" in unrolled loop.
    // For now we count a conditional branch on a backedge and a comparison
    // feeding it.
    unsigned BEInsns;
    /// Allow partial unrolling (unrolling of loops to expand the size of the
    /// loop body, not only to eliminate small constant-trip-count loops).
    bool Partial;
    /// Allow runtime unrolling (unrolling of loops to expand the size of the
    /// loop body even when the number of loop iterations is not known at
    /// compile time).
    bool Runtime;
    /// Allow generation of a loop remainder (extra iterations after unroll).
    bool AllowRemainder;
    /// Allow emitting expensive instructions (such as divisions) when computing
    /// the trip count of a loop for runtime unrolling.
    bool AllowExpensiveTripCount;
    /// Apply loop unroll on any kind of loop
    /// (mainly to loops that fail runtime unrolling).
    bool Force;
    /// Allow using trip count upper bound to unroll loops.
    bool UpperBound;
    /// Allow unrolling of all the iterations of the runtime loop remainder.
    bool UnrollRemainder;
    /// Allow unroll and jam. Used to enable unroll and jam for the target.
    bool UnrollAndJam;
    /// Threshold for unroll and jam, for inner loop size. The 'Threshold'
    /// value above is used during unroll and jam for the outer loop size.
    /// This value is used in the same manner to limit the size of the inner
    /// loop.
    unsigned UnrollAndJamInnerLoopThreshold;
    /// Don't allow loop unrolling to simulate more than this number of
    /// iterations when checking full unroll profitability
    unsigned MaxIterationsCountToAnalyze;
    /// Disable runtime unrolling by default for vectorized loops.
    bool UnrollVectorizedLoop = false;
    /// Don't allow runtime unrolling if expanding the trip count takes more
    /// than SCEVExpansionBudget.
    unsigned SCEVExpansionBudget;
    /// Allow runtime unrolling multi-exit loops. Should only be set if the
    /// target determined that multi-exit unrolling is profitable for the loop.
    /// Fall back to the generic logic to determine whether multi-exit unrolling
    /// is profitable if set to false.
    bool RuntimeUnrollMultiExit;
    /// Allow unrolling to add parallel reduction phis.
    bool AddAdditionalAccumulators;
  };
 
  /// Get target-customized preferences for the generic loop unrolling
  /// transformation. The caller will initialize UP with the current
  /// target-independent defaults.
  LLVM_ABI void getUnrollingPreferences(Loop *L, ScalarEvolution &,
                                        UnrollingPreferences &UP,
                                        OptimizationRemarkEmitter *ORE) const;
 
  /// Query the target whether it would be profitable to convert the given loop
  /// into a hardware loop.
  LLVM_ABI bool isHardwareLoopProfitable(Loop *L, ScalarEvolution &SE,
                                         AssumptionCache &AC,
                                         TargetLibraryInfo *LibInfo,
                                         HardwareLoopInfo &HWLoopInfo) const;
 
  // Query the target for which minimum vectorization factor epilogue
  // vectorization should be considered.
  LLVM_ABI unsigned getEpilogueVectorizationMinVF() const;
 
  /// Query the target whether it would be preferred to create a tail-folded
  /// vector loop, which can avoid the need to emit a scalar epilogue loop.
  LLVM_ABI bool preferTailFoldingOverEpilogue(TailFoldingInfo *TFI) const;
 
  /// Query the target what the preferred style of tail folding is.
  LLVM_ABI TailFoldingStyle getPreferredTailFoldingStyle() const;
 
  // Parameters that control the loop peeling transformation
  struct PeelingPreferences {
    /// A forced peeling factor (the number of bodied of the original loop
    /// that should be peeled off before the loop body). When set to 0, the
    /// a peeling factor based on profile information and other factors.
    unsigned PeelCount;
    /// Allow peeling off loop iterations.
    bool AllowPeeling;
    /// Allow peeling off loop iterations for loop nests.
    bool AllowLoopNestsPeeling;
    /// Allow peeling basing on profile. Uses to enable peeling off all
    /// iterations basing on provided profile.
    /// If the value is true the peeling cost model can decide to peel only
    /// some iterations and in this case it will set this to false.
    bool PeelProfiledIterations;
 
    /// Peel off the last PeelCount loop iterations.
    bool PeelLast;
  };
 
  /// Get target-customized preferences for the generic loop peeling
  /// transformation. The caller will initialize \p PP with the current
  /// target-independent defaults with information from \p L and \p SE.
  LLVM_ABI void getPeelingPreferences(Loop *L, ScalarEvolution &SE,
                                      PeelingPreferences &PP) const;
 
  /// Targets can implement their own combinations for target-specific
  /// intrinsics. This function will be called from the InstCombine pass every
  /// time a target-specific intrinsic is encountered.
  ///
  /// \returns std::nullopt to not do anything target specific or a value that
  /// will be returned from the InstCombiner. It is possible to return null and
  /// stop further processing of the intrinsic by returning nullptr.
  LLVM_ABI std::optional<Instruction *>
  instCombineIntrinsic(InstCombiner &IC, IntrinsicInst &II) const;
  /// Can be used to implement target-specific instruction combining.
  /// \see instCombineIntrinsic
  LLVM_ABI std::optional<Value *>
  simplifyDemandedUseBitsIntrinsic(InstCombiner &IC, IntrinsicInst &II,
                                   APInt DemandedMask, KnownBits &Known,
                                   bool &KnownBitsComputed) const;
  /// Can be used to implement target-specific instruction combining.
  /// \see instCombineIntrinsic
  LLVM_ABI std::optional<Value *> simplifyDemandedVectorEltsIntrinsic(
      InstCombiner &IC, IntrinsicInst &II, APInt DemandedElts, APInt &UndefElts,
      APInt &UndefElts2, APInt &UndefElts3,
      std::function<void(Instruction *, unsigned, APInt, APInt &)>
          SimplifyAndSetOp) const;
  /// @}
 
  /// \name Scalar Target Information
  /// @{
 
  /// Flags indicating the kind of support for population count.
  ///
  /// Compared to the SW implementation, HW support is supposed to
  /// significantly boost the performance when the population is dense, and it
  /// may or may not degrade performance if the population is sparse. A HW
  /// support is considered as "Fast" if it can outperform, or is on a par
  /// with, SW implementation when the population is sparse; otherwise, it is
  /// considered as "Slow".
  enum PopcntSupportKind { PSK_Software, PSK_SlowHardware, PSK_FastHardware };
 
  /// Return true if the specified immediate is legal add immediate, that
  /// is the target has add instructions which can add a register with the
  /// immediate without having to materialize the immediate into a register.
  LLVM_ABI bool isLegalAddImmediate(int64_t Imm) const;
 
  /// Return true if adding the specified scalable immediate is legal, that is
  /// the target has add instructions which can add a register with the
  /// immediate (multiplied by vscale) without having to materialize the
  /// immediate into a register.
  LLVM_ABI bool isLegalAddScalableImmediate(int64_t Imm) const;
 
  /// Return true if the specified immediate is legal icmp immediate,
  /// that is the target has icmp instructions which can compare a register
  /// against the immediate without having to materialize the immediate into a
  /// register.
  LLVM_ABI bool isLegalICmpImmediate(int64_t Imm) const;
 
  /// Return true if replacing the relational loop exit comparison \p Cond
  /// with an equality comparison against \p PostIncExitValue is profitable.
  LLVM_ABI bool
  preferLoopExitWithEqualityComparison(const ICmpInst &Cond,
                                       const APInt &PostIncExitValue) const;
 
  /// Return true if the addressing mode represented by AM is legal for
  /// this target, for a load/store of the specified type.
  /// The type may be VoidTy, in which case only return true if the addressing
  /// mode is legal for a load/store of any legal type.
  /// If target returns true in LSRWithInstrQueries(), I may be valid.
  /// \param ScalableOffset represents a quantity of bytes multiplied by vscale,
  /// an invariant value known only at runtime. Most targets should not accept
  /// a scalable offset.
  ///
  /// TODO: Handle pre/postinc as well.
  LLVM_ABI bool isLegalAddressingMode(Type *Ty, GlobalValue *BaseGV,
                                      int64_t BaseOffset, bool HasBaseReg,
                                      int64_t Scale, unsigned AddrSpace = 0,
                                      Instruction *I = nullptr,
                                      int64_t ScalableOffset = 0) const;
 
  /// Return true if LSR cost of C1 is lower than C2.
  LLVM_ABI bool isLSRCostLess(const TargetTransformInfo::LSRCost &C1,
                              const TargetTransformInfo::LSRCost &C2) const;
 
  /// Return true if LSR major cost is number of registers. Targets which
  /// implement their own isLSRCostLess and unset number of registers as major
  /// cost should return false, otherwise return true.
  LLVM_ABI bool isNumRegsMajorCostOfLSR() const;
 
  /// Return true if LSR should drop a found solution if it's calculated to be
  /// less profitable than the baseline.
  LLVM_ABI bool shouldDropLSRSolutionIfLessProfitable() const;
 
  /// \returns true if LSR should not optimize a chain that includes \p I.
  LLVM_ABI bool isProfitableLSRChainElement(Instruction *I) const;
 
  /// Return true if the target can fuse a compare and branch.
  /// Loop-strength-reduction (LSR) uses that knowledge to adjust its cost
  /// calculation for the instructions in a loop.
  LLVM_ABI bool canMacroFuseCmp() const;
 
  /// Return true if the target can save a compare for loop count, for example
  /// hardware loop saves a compare.
  LLVM_ABI bool canSaveCmp(Loop *L, CondBrInst **BI, ScalarEvolution *SE,
                           LoopInfo *LI, DominatorTree *DT, AssumptionCache *AC,
                           TargetLibraryInfo *LibInfo) const;
 
  /// Which addressing mode Loop Strength Reduction will try to generate.
  enum AddressingModeKind {
    AMK_None = 0x0,        ///< Don't prefer any addressing mode
    AMK_PreIndexed = 0x1,  ///< Prefer pre-indexed addressing mode
    AMK_PostIndexed = 0x2, ///< Prefer post-indexed addressing mode
    AMK_All = 0x3,         ///< Consider all addressing modes
    LLVM_MARK_AS_BITMASK_ENUM(/*LargestValue=*/AMK_All)
  };
 
  /// Return the preferred addressing mode LSR should make efforts to generate.
  LLVM_ABI AddressingModeKind
  getPreferredAddressingMode(const Loop *L, ScalarEvolution *SE) const;
 
  /// Some targets only support masked load/store with a constant mask.
  enum MaskKind {
    VariableOrConstantMask,
    ConstantMask,
  };
 
  /// Return true if the target supports masked store.
  LLVM_ABI bool
  isLegalMaskedStore(Type *DataType, Align Alignment, unsigned AddressSpace,
                     MaskKind MaskKind = VariableOrConstantMask) const;
  /// Return true if the target supports masked load.
  LLVM_ABI bool
  isLegalMaskedLoad(Type *DataType, Align Alignment, unsigned AddressSpace,
                    MaskKind MaskKind = VariableOrConstantMask) const;
 
  /// Return true if the target supports speculatively loading \p DataType from
  /// address space \p AddressSpace, i.e. @llvm.can.load.speculatively can
  /// return true for the store size of \p DataType.
  LLVM_ABI bool isLegalSpeculativeLoad(Type *DataType,
                                       unsigned AddressSpace) const;
 
  /// Return true if the target supports nontemporal store.
  LLVM_ABI bool isLegalNTStore(Type *DataType, Align Alignment) const;
  /// Return true if the target supports nontemporal load.
  LLVM_ABI bool isLegalNTLoad(Type *DataType, Align Alignment) const;
 
  /// \Returns true if the target supports broadcasting a load to a vector of
  /// type <NumElements x ElementTy>.
  LLVM_ABI bool isLegalBroadcastLoad(Type *ElementTy,
                                     ElementCount NumElements) const;
 
  /// Return true if the target supports masked scatter.
  LLVM_ABI bool isLegalMaskedScatter(Type *DataType, Align Alignment) const;
  /// Return true if the target supports masked gather.
  LLVM_ABI bool isLegalMaskedGather(Type *DataType, Align Alignment) const;
  /// Return true if the target forces scalarizing of llvm.masked.gather
  /// intrinsics.
  LLVM_ABI bool forceScalarizeMaskedGather(VectorType *Type,
                                           Align Alignment) const;
  /// Return true if the target forces scalarizing of llvm.masked.scatter
  /// intrinsics.
  LLVM_ABI bool forceScalarizeMaskedScatter(VectorType *Type,
                                            Align Alignment) const;
 
  /// Return true if the target supports masked compress store.
  LLVM_ABI bool isLegalMaskedCompressStore(Type *DataType,
                                           Align Alignment) const;
  /// Return true if the target supports masked expand load.
  LLVM_ABI bool isLegalMaskedExpandLoad(Type *DataType, Align Alignment) const;
 
  /// Return true if the target supports strided load.
  LLVM_ABI bool isLegalStridedLoadStore(Type *DataType, Align Alignment) const;
 
  /// Return true is the target supports interleaved access for the given vector
  /// type \p VTy, interleave factor \p Factor, alignment \p Alignment and
  /// address space \p AddrSpace.
  LLVM_ABI bool isLegalInterleavedAccessType(VectorType *VTy, unsigned Factor,
                                             Align Alignment,
                                             unsigned AddrSpace) const;
 
  // Return true if the target supports masked vector histograms.
  LLVM_ABI bool isLegalMaskedVectorHistogram(Type *AddrType,
                                             Type *DataType) const;
 
  /// Return true if this is an alternating opcode pattern that can be lowered
  /// to a single instruction on the target. In X86 this is for the addsub
  /// instruction which corrsponds to a Shuffle + Fadd + FSub pattern in IR.
  /// This function expectes two opcodes: \p Opcode1 and \p Opcode2 being
  /// selected by \p OpcodeMask. The mask contains one bit per lane and is a `0`
  /// when \p Opcode0 is selected and `1` when Opcode1 is selected.
  /// \p VecTy is the vector type of the instruction to be generated.
  /// \p Scalars are the scalar instructions of the lanes, if known. The target
  /// may use them to find the patterns, which depend on the operands, like
  /// the alternating fused multiply-add.
  LLVM_ABI bool isLegalAltInstr(VectorType *VecTy, unsigned Opcode0,
                                unsigned Opcode1,
                                const SmallBitVector &OpcodeMask,
                                ArrayRef<const Value *> Scalars = {}) const;
 
  /// Enum describing the source/producer of a mask.
  enum class MaskSource {
    /// The operation is unmasked.
    None,
    /// The operation is masked with an arbitrary predicate.
    ArbitraryPredicate,
    /// The operation is masked with a contiguous active lane mask.
    ActiveLaneMask,
  };
 
  /// Return true if the target supports loading or storing \p NumVectors
  /// contiguous vectors of type \p VectorTy as a single operation. A null
  /// \p VectorTy queries whether the target supports this operation in
  /// general.
  ///
  /// \p CastHint is non-null if a stored value is produced by a cast or a
  /// loaded value is consumed by one.
  LLVM_ABI bool hasMultiVectorLoadStore(
      unsigned NumVectors, MaskSource Mask, VectorType *VectorTy = nullptr,
      bool IsStore = false,
      std::optional<Instruction::CastOps> CastHint = std::nullopt) const;
 
  /// Return true if we should be enabling ordered reductions for the target.
  LLVM_ABI bool enableOrderedReductions() const;
 
  /// Return true if the target has a unified operation to calculate division
  /// and remainder. If so, the additional implicit multiplication and
  /// subtraction required to calculate a remainder from division are free. This
  /// can enable more aggressive transformations for division and remainder than
  /// would typically be allowed using throughput or size cost models.
  LLVM_ABI bool hasDivRemOp(Type *DataType, bool IsSigned) const;
 
  /// Return true if the given instruction (assumed to be a memory access
  /// instruction) has a volatile variant. If that's the case then we can avoid
  /// addrspacecast to generic AS for volatile loads/stores. Default
  /// implementation returns false, which prevents address space inference for
  /// volatile loads/stores.
  LLVM_ABI bool hasVolatileVariant(Instruction *I, unsigned AddrSpace) const;
 
  /// Return true if target doesn't mind addresses in vectors.
  LLVM_ABI bool prefersVectorizedAddressing() const;
 
  /// Return the cost of the scaling factor used in the addressing
  /// mode represented by AM for this target, for a load/store
  /// of the specified type.
  /// If the AM is supported, the return value must be >= 0.
  /// If the AM is not supported, it returns a negative value.
  /// TODO: Handle pre/postinc as well.
  LLVM_ABI InstructionCost getScalingFactorCost(Type *Ty, GlobalValue *BaseGV,
                                                StackOffset BaseOffset,
                                                bool HasBaseReg, int64_t Scale,
                                                unsigned AddrSpace = 0) const;
 
  /// Return true if the loop strength reduce pass should make
  /// Instruction* based TTI queries to isLegalAddressingMode(). This is
  /// needed on SystemZ, where e.g. a memcpy can only have a 12 bit unsigned
  /// immediate offset and no index register.
  LLVM_ABI bool LSRWithInstrQueries() const;
 
  /// Return true if it's free to truncate a value of type Ty1 to type
  /// Ty2. e.g. On x86 it's free to truncate a i32 value in register EAX to i16
  /// by referencing its sub-register AX.
  LLVM_ABI bool isTruncateFree(Type *Ty1, Type *Ty2) const;
 
  /// Return true if it is profitable to hoist instruction in the
  /// then/else to before if.
  LLVM_ABI bool isProfitableToHoist(Instruction *I) const;
 
  LLVM_ABI bool useAA() const;
 
  /// Return true if this type is legal.
  LLVM_ABI bool isTypeLegal(Type *Ty) const;
 
  /// Returns the estimated number of registers required to represent \p Ty.
  LLVM_ABI unsigned getRegUsageForType(Type *Ty) const;
 
  /// Return true if switches should be turned into lookup tables for the
  /// target.
  LLVM_ABI bool shouldBuildLookupTables() const;
 
  /// Return true if switches should be turned into lookup tables
  /// containing this constant value for the target.
  LLVM_ABI bool shouldBuildLookupTablesForConstant(Constant *C) const;
 
  /// Return the minimum bit width to use for integer switch lookup table
  /// elements on this target.
  LLVM_ABI unsigned getMinimumLookupTableEntryBitWidth() const;
 
  /// Return true if lookup tables should be turned into relative lookup tables.
  LLVM_ABI bool shouldBuildRelLookupTables() const;
 
  /// Return true if the input function which is cold at all call sites,
  ///  should use coldcc calling convention.
  LLVM_ABI bool useColdCCForColdCall(Function &F) const;
 
  /// Return true if the input function is internal, should use fastcc calling
  /// convention.
  LLVM_ABI bool useFastCCForInternalCall(Function &F) const;
 
  /// Identifies if the vector form of the intrinsic has a scalar operand.
  LLVM_ABI bool isTargetIntrinsicWithScalarOpAtArg(Intrinsic::ID ID,
                                                   unsigned ScalarOpdIdx) const;
 
  /// Identifies if the vector form of the intrinsic is overloaded on the type
  /// of the operand at index \p OpdIdx, or on the return type if \p OpdIdx is
  /// -1.
  LLVM_ABI bool isTargetIntrinsicWithOverloadTypeAtArg(Intrinsic::ID ID,
                                                       int OpdIdx) const;
 
  /// Identifies if the vector form of the intrinsic that returns a struct is
  /// overloaded at the struct element index \p RetIdx.
  LLVM_ABI bool
  isTargetIntrinsicWithStructReturnOverloadAtField(Intrinsic::ID ID,
                                                   int RetIdx) const;
 
  using VectorInstrContext = llvm::VectorInstrContext;
 
  /// Combines 2 context hints into a single value. If both are equal, keep the
  /// shared context, otherwise fall back to no specific context.
  LLVM_ABI static TargetTransformInfo::VectorInstrContext
  combineVectorInstrContexts(TargetTransformInfo::VectorInstrContext Ctx1,
                             TargetTransformInfo::VectorInstrContext Ctx2);
 
  /// Stores information about the uses of a build vector
  struct BuildVectorUseOp {
    unsigned Opcode = 0;
    Intrinsic::ID IntrinsicID = Intrinsic::not_intrinsic;
    int OperandIndex = -1;
    BuildVectorUseOp(unsigned Opcode, Intrinsic::ID IntrinsicID,
                     int OperandIndex)
        : Opcode(Opcode), IntrinsicID(IntrinsicID), OperandIndex(OperandIndex) {
    }
  };
 
  /// Calculates a VectorInstrContext from \p I.
  LLVM_ABI static VectorInstrContext
  getVectorInstrContextHint(const Instruction *I);
 
  /// Calculates a VectorInstrContext from the values in \p VL at indices in
  /// \p DemandedElts.
  LLVM_ABI static VectorInstrContext
  getVectorInstrContextHint(ArrayRef<Value *> VL, const APInt &DemandedElts);
 
  /// Calculates a VectorInstrContext for buildvector-like gather sequences.
  ///
  /// \p GatherUserOps must collect all users of \p Scalars relevant for
  /// determining whether a splat can be folded as a scalar operand. It returns
  /// false if those users cannot be gathered in the required form.
  LLVM_ABI VectorInstrContext getBuildVectorContextHint(
      ArrayRef<int> Mask, ArrayRef<Value *> Scalars,
      function_ref<bool(SmallVectorImpl<BuildVectorUseOp> &)> GatherUseOps)
      const;
 
  /// Estimate the overhead of scalarizing an instruction. Insert and Extract
  /// are set if the demanded result elements need to be inserted and/or
  /// extracted from vectors.  The involved values may be passed in VL if
  /// Insert is true.
  LLVM_ABI InstructionCost getScalarizationOverhead(
      VectorType *Ty, const APInt &DemandedElts, bool Insert, bool Extract,
      TTI::TargetCostKind CostKind, bool ForPoisonSrc = true,
      ArrayRef<Value *> VL = {},
      TTI::VectorInstrContext VIC = TTI::VectorInstrContext::None) const;
 
  /// Estimate the overhead of scalarizing operands with the given types. The
  /// (potentially vector) types to use for each of argument are passes via Tys.
  LLVM_ABI InstructionCost getOperandsScalarizationOverhead(
      ArrayRef<Type *> Tys, TTI::TargetCostKind CostKind,
      TTI::VectorInstrContext VIC = TTI::VectorInstrContext::None) const;
 
  /// If target has efficient vector element load/store instructions, it can
  /// return true here so that insertion/extraction costs are not added to
  /// the scalarization cost of a load/store.
  LLVM_ABI bool supportsEfficientVectorElementLoadStore() const;
 
  /// If the target supports tail calls.
  LLVM_ABI bool supportsTailCalls() const;
 
  /// If target supports tail call on \p CB
  LLVM_ABI bool supportsTailCallFor(const CallBase *CB) const;
 
  /// Don't restrict interleaved unrolling to small loops.
  LLVM_ABI bool enableAggressiveInterleaving(bool LoopHasReductions) const;
 
  /// Returns options for expansion of memcmp. IsZeroCmp is
  // true if this is the expansion of memcmp(p1, p2, s) == 0.
  struct MemCmpExpansionOptions {
    // Return true if memcmp expansion is enabled.
    operator bool() const { return MaxNumLoads > 0; }
 
    // Maximum number of load operations.
    unsigned MaxNumLoads = 0;
 
    // The list of available load sizes (in bytes), sorted in decreasing order.
    SmallVector<unsigned, 8> LoadSizes;
 
    // For memcmp expansion, allow up to this number of load pairs per block.
    // As an example, this may allow 'memcmp(a, b, 3) == 0' in a single block:
    //   a0 = load2bytes &a[0]
    //   b0 = load2bytes &b[0]
    //   a2 = load1byte  &a[2]
    //   b2 = load1byte  &b[2]
    //   r  = cmp eq (a0 ^ b0 | a2 ^ b2), 0
    // Equality comparisons combine the differences with xor/or. Ordering
    // comparisons pack the loads in memory order into a wider integer before
    // comparing, without exceeding the target's preferred load width.
    unsigned NumLoadsPerBlock = 1;
 
    // Set to true to allow overlapping loads. For example, 7-byte compares can
    // be done with two 4-byte compares instead of 4+2+1-byte compares. This
    // requires all loads in LoadSizes to be doable in an unaligned way.
    bool AllowOverlappingLoads = false;
 
    // Sometimes, the amount of data that needs to be compared is smaller than
    // the standard register size, but it cannot be loaded with just one load
    // instruction. For example, if the size of the memory comparison is 6
    // bytes, we can handle it more efficiently by loading all 6 bytes in a
    // single block and generating an 8-byte number, instead of generating two
    // separate blocks with conditional jumps for 4 and 2 byte loads. This
    // approach simplifies the process and produces the comparison result as
    // normal. This array lists the allowed sizes of memcmp tails that can be
    // merged into one block
    SmallVector<unsigned, 4> AllowedTailExpansions;
  };
  LLVM_ABI MemCmpExpansionOptions enableMemCmpExpansion(bool OptSize,
                                                        bool IsZeroCmp) const;
 
  /// Should the Select Optimization pass be enabled and ran.
  LLVM_ABI bool enableSelectOptimize() const;
 
  /// Should the Select Optimization pass treat the given instruction like a
  /// select, potentially converting it to a conditional branch. This can
  /// include select-like instructions like or(zext(c), x) that can be converted
  /// to selects.
  LLVM_ABI bool shouldTreatInstructionLikeSelect(const Instruction *I) const;
 
  /// Enable matching of interleaved access groups.
  LLVM_ABI bool enableInterleavedAccessVectorization() const;
 
  /// Enable matching of interleaved access groups that contain predicated
  /// accesses or gaps and therefore vectorized using masked
  /// vector loads/stores.
  LLVM_ABI bool enableMaskedInterleavedAccessVectorization() const;
 
  /// Indicate that it is potentially unsafe to automatically vectorize
  /// floating-point operations because the semantics of vector and scalar
  /// floating-point semantics may differ. For example, ARM NEON v7 SIMD math
  /// does not support IEEE-754 denormal numbers, while depending on the
  /// platform, scalar floating-point math does.
  /// This applies to floating-point math operations and calls, not memory
  /// operations, shuffles, or casts.
  LLVM_ABI bool isFPVectorizationPotentiallyUnsafe() const;
 
  /// Determine if the target supports unaligned memory accesses.
  LLVM_ABI bool allowsMisalignedMemoryAccesses(LLVMContext &Context,
                                               unsigned BitWidth,
                                               unsigned AddressSpace = 0,
                                               Align Alignment = Align(1),
                                               unsigned *Fast = nullptr) const;
 
  /// Return hardware support for population count.
  LLVM_ABI PopcntSupportKind getPopcntSupport(unsigned IntTyWidthInBit) const;
 
  /// Return true if the hardware has a fast square-root instruction.
  LLVM_ABI bool haveFastSqrt(Type *Ty) const;
 
  /// Return true if the cost of the instruction is too high to speculatively
  /// execute and should be kept behind a branch.
  /// This normally just wraps around a getInstructionCost() call, but some
  /// targets might report a low TCK_SizeAndLatency value that is incompatible
  /// with the fixed TCC_Expensive value.
  /// NOTE: This assumes the instruction passes isSafeToSpeculativelyExecute().
  LLVM_ABI bool isExpensiveToSpeculativelyExecute(const Instruction *I) const;
 
  /// Return true if it is faster to check if a floating-point value is NaN
  /// (or not-NaN) versus a comparison against a constant FP zero value.
  /// Targets should override this if materializing a 0.0 for comparison is
  /// generally as cheap as checking for ordered/unordered.
  LLVM_ABI bool isFCmpOrdCheaperThanFCmpZero(Type *Ty) const;
 
  /// Return the expected cost of supporting the floating point operation
  /// of the specified type.
  LLVM_ABI InstructionCost getFPOpCost(Type *Ty) const;
 
  /// Return the expected cost of materializing for the given integer
  /// immediate of the specified type.
  LLVM_ABI InstructionCost getIntImmCost(const APInt &Imm, Type *Ty,
                                         TargetCostKind CostKind) const;
 
  /// Return the expected cost of materialization for the given integer
  /// immediate of the specified type for a given instruction. The cost can be
  /// zero if the immediate can be folded into the specified instruction.
  LLVM_ABI InstructionCost getIntImmCostInst(unsigned Opc, unsigned Idx,
                                             const APInt &Imm, Type *Ty,
                                             TargetCostKind CostKind,
                                             Instruction *Inst = nullptr) const;
  LLVM_ABI InstructionCost getIntImmCostIntrin(Intrinsic::ID IID, unsigned Idx,
                                               const APInt &Imm, Type *Ty,
                                               TargetCostKind CostKind) const;
 
  /// Return the expected cost for the given integer when optimising
  /// for size. This is different than the other integer immediate cost
  /// functions in that it is subtarget agnostic. This is useful when you e.g.
  /// target one ISA such as Aarch32 but smaller encodings could be possible
  /// with another such as Thumb. This return value is used as a penalty when
  /// the total costs for a constant is calculated (the bigger the cost, the
  /// more beneficial constant hoisting is).
  LLVM_ABI InstructionCost getIntImmCodeSizeCost(unsigned Opc, unsigned Idx,
                                                 const APInt &Imm,
                                                 Type *Ty) const;
 
  /// It can be advantageous to detach complex constants from their uses to make
  /// their generation cheaper. This hook allows targets to report when such
  /// transformations might negatively effect the code generation of the
  /// underlying operation. The motivating example is divides whereby hoisting
  /// constants prevents the code generator's ability to transform them into
  /// combinations of simpler operations.
  LLVM_ABI bool preferToKeepConstantsAttached(const Instruction &Inst,
                                              const Function &Fn) const;
 
  /// @}
 
  /// \name Vector Target Information
  /// @{
 
  /// The various kinds of shuffle patterns for vector queries.
  enum ShuffleKind {
    SK_Broadcast,        ///< Broadcast element 0 to all other elements.
    SK_Reverse,          ///< Reverse the order of the vector.
    SK_Select,           ///< Selects elements from the corresponding lane of
                         ///< either source operand. This is equivalent to a
                         ///< vector select with a constant condition operand.
    SK_Transpose,        ///< Transpose two vectors.
    SK_InsertSubvector,  ///< InsertSubvector. Index indicates start offset.
    SK_ExtractSubvector, ///< ExtractSubvector Index indicates start offset.
    SK_PermuteTwoSrc,    ///< Merge elements from two source vectors into one
                         ///< with any shuffle mask.
    SK_PermuteSingleSrc, ///< Shuffle elements of single source vector with any
                         ///< shuffle mask.
    SK_Splice            ///< Concatenates elements from the first input vector
                         ///< with elements of the second input vector. Returning
                         ///< a vector of the same type as the input vectors.
                         ///< Index indicates start offset in first input vector.
  };
 
  /// Additional information about an operand's possible values.
  enum OperandValueKind {
    OK_AnyValue,               // Operand can have any value.
    OK_UniformValue,           // Operand is uniform (splat of a value).
    OK_UniformConstantValue,   // Operand is uniform constant.
    OK_NonUniformConstantValue // Operand is a non uniform constant value.
  };
 
  /// Additional properties of an operand's values.
  enum OperandValueProperties {
    OP_None = 0,
    OP_PowerOf2 = 1,
    OP_NegatedPowerOf2 = 2,
  };
 
  // Describe the values an operand can take.  We're in the process
  // of migrating uses of OperandValueKind and OperandValueProperties
  // to use this class, and then will change the internal representation.
  struct OperandValueInfo {
    OperandValueKind Kind = OK_AnyValue;
    OperandValueProperties Properties = OP_None;
 
    bool isConstant() const {
      return Kind == OK_UniformConstantValue || Kind == OK_NonUniformConstantValue;
    }
    bool isUniform() const {
      return Kind == OK_UniformConstantValue || Kind == OK_UniformValue;
    }
    bool isPowerOf2() const {
      return Properties == OP_PowerOf2;
    }
    bool isNegatedPowerOf2() const {
      return Properties == OP_NegatedPowerOf2;
    }
 
    OperandValueInfo getNoProps() const {
      return {Kind, OP_None};
    }
 
    OperandValueInfo mergeWith(const OperandValueInfo OpInfoY) {
      OperandValueKind MergeKind = OK_AnyValue;
      if (isConstant() && OpInfoY.isConstant())
        MergeKind = OK_NonUniformConstantValue;
 
      OperandValueProperties MergeProp = OP_None;
      if (Properties == OpInfoY.Properties)
        MergeProp = Properties;
      return {MergeKind, MergeProp};
    }
  };
 
  /// \return the number of registers in the target-provided register class.
  LLVM_ABI unsigned getNumberOfRegisters(unsigned ClassID) const;
 
  /// \return true if the target supports load/store that enables fault
  /// suppression of memory operands when the source condition is false.
  LLVM_ABI bool hasConditionalLoadStoreForType(Type *Ty, bool IsStore) const;
 
  /// \return the target-provided register class ID for the provided type,
  /// accounting for type promotion and other type-legalization techniques that
  /// the target might apply. However, it specifically does not account for the
  /// scalarization or splitting of vector types. Should a vector type require
  /// scalarization or splitting into multiple underlying vector registers, that
  /// type should be mapped to a register class containing no registers.
  /// Specifically, this is designed to provide a simple, high-level view of the
  /// register allocation later performed by the backend. These register classes
  /// don't necessarily map onto the register classes used by the backend.
  /// FIXME: It's not currently possible to determine how many registers
  /// are used by the provided type.
  LLVM_ABI unsigned getRegisterClassForType(bool Vector,
                                            Type *Ty = nullptr) const;
 
  /// \return the target-provided register class name
  LLVM_ABI const char *getRegisterClassName(unsigned ClassID) const;
 
  /// \return the cost of spilling a register in the target-provided register
  /// class to the stack.
  LLVM_ABI InstructionCost
  getRegisterClassSpillCost(unsigned ClassID, TargetCostKind CostKind) const;
 
  /// \return the cost of reloading a register in the target-provided register
  /// class from the stack.
  LLVM_ABI InstructionCost
  getRegisterClassReloadCost(unsigned ClassID, TargetCostKind CostKind) const;
 
  enum RegisterKind { RGK_Scalar, RGK_FixedWidthVector, RGK_ScalableVector };
 
  /// \return The width of the largest scalar or vector register type.
  LLVM_ABI TypeSize getRegisterBitWidth(RegisterKind K) const;
 
  /// \return The width of the smallest vector register type.
  LLVM_ABI unsigned getMinVectorRegisterBitWidth() const;
 
  /// \return the value of vscale to tune the cost model for.
  LLVM_ABI std::optional<unsigned> getVScaleForTuning() const;
 
  /// \return True if the vectorization factor should be chosen to
  /// make the vector of the smallest element type match the size of a
  /// vector register. For wider element types, this could result in
  /// creating vectors that span multiple vector registers.
  /// If false, the vectorization factor will be chosen based on the
  /// size of the widest element type.
  /// \p K Register Kind for vectorization.
  LLVM_ABI bool
  shouldMaximizeVectorBandwidth(TargetTransformInfo::RegisterKind K) const;
 
  /// \return The minimum vectorization factor for types of given element
  /// bit width, or 0 if there is no minimum VF. The returned value only
  /// applies when shouldMaximizeVectorBandwidth returns true.
  /// If IsScalable is true, the returned ElementCount must be a scalable VF.
  LLVM_ABI ElementCount getMinimumVF(unsigned ElemWidth, bool IsScalable) const;
 
  /// \return The maximum vectorization factor for types of given element
  /// bit width and opcode, or 0 if there is no maximum VF.
  /// Currently only used by the SLP vectorizer.
  LLVM_ABI unsigned getMaximumVF(unsigned ElemWidth, unsigned Opcode) const;
 
  /// \return The minimum vectorization factor for the store instruction. Given
  /// the initial estimation of the minimum vector factor and store value type,
  /// it tries to find possible lowest VF, which still might be profitable for
  /// the vectorization.
  /// \param VF Initial estimation of the minimum vector factor.
  /// \param ScalarMemTy Scalar memory type of the store operation.
  /// \param ScalarValTy Scalar type of the stored value.
  /// \param Alignment Alignment of the store
  /// \param AddrSpace Address space of the store
  /// Currently only used by the SLP vectorizer.
  LLVM_ABI unsigned getStoreMinimumVF(unsigned VF, Type *ScalarMemTy,
                                      Type *ScalarValTy, Align Alignment,
                                      unsigned AddrSpace) const;
 
  /// \return True if it should be considered for address type promotion.
  /// \p AllowPromotionWithoutCommonHeader Set true if promoting \p I is
  /// profitable without finding other extensions fed by the same input.
  LLVM_ABI bool shouldConsiderAddressTypePromotion(
      const Instruction &I, bool &AllowPromotionWithoutCommonHeader) const;
 
  /// \return The size of a cache line in bytes.
  LLVM_ABI unsigned getCacheLineSize() const;
 
  /// The possible cache levels
  enum class CacheLevel {
    L1D, // The L1 data cache
    L2D, // The L2 data cache
 
    // We currently do not model L3 caches, as their sizes differ widely between
    // microarchitectures. Also, we currently do not have a use for L3 cache
    // size modeling yet.
  };
 
  /// \return The size of the cache level in bytes, if available.
  LLVM_ABI std::optional<unsigned> getCacheSize(CacheLevel Level) const;
 
  /// \return The associativity of the cache level, if available.
  LLVM_ABI std::optional<unsigned>
  getCacheAssociativity(CacheLevel Level) const;
 
  /// \return The minimum architectural page size for the target.
  LLVM_ABI std::optional<unsigned> getMinPageSize() const;
 
  /// \return How much before a load we should place the prefetch
  /// instruction.  This is currently measured in number of
  /// instructions.
  LLVM_ABI unsigned getPrefetchDistance() const;
 
  /// Some HW prefetchers can handle accesses up to a certain constant stride.
  /// Sometimes prefetching is beneficial even below the HW prefetcher limit,
  /// and the arguments provided are meant to serve as a basis for deciding this
  /// for a particular loop.
  ///
  /// \param NumMemAccesses        Number of memory accesses in the loop.
  /// \param NumStridedMemAccesses Number of the memory accesses that
  ///                              ScalarEvolution could find a known stride
  ///                              for.
  /// \param NumPrefetches         Number of software prefetches that will be
  ///                              emitted as determined by the addresses
  ///                              involved and the cache line size.
  /// \param HasCall               True if the loop contains a call.
  ///
  /// \return This is the minimum stride in bytes where it makes sense to start
  ///         adding SW prefetches. The default is 1, i.e. prefetch with any
  ///         stride.
  LLVM_ABI unsigned getMinPrefetchStride(unsigned NumMemAccesses,
                                         unsigned NumStridedMemAccesses,
                                         unsigned NumPrefetches,
                                         bool HasCall) const;
 
  /// \return The maximum number of iterations to prefetch ahead.  If
  /// the required number of iterations is more than this number, no
  /// prefetching is performed.
  LLVM_ABI unsigned getMaxPrefetchIterationsAhead() const;
 
  /// \return True if prefetching should also be done for writes.
  LLVM_ABI bool enableWritePrefetching() const;
 
  /// \return if target want to issue a prefetch in address space \p AS.
  LLVM_ABI bool shouldPrefetchAddressSpace(unsigned AS) const;
 
  /// \return The cost of a partial reduction, which is a reduction from a
  /// vector to another vector with fewer elements of larger size. They are
  /// represented by the llvm.vector.partial.reduce.add and
  /// llvm.vector.partial.reduce.fadd intrinsics, which take an accumulator of
  /// type \p AccumType and a second vector operand to be accumulated, whose
  /// element count is specified by \p VF. The type of reduction is specified by
  /// \p Opcode. The second operand passed to the intrinsic could be the result
  /// of an extend, such as sext or zext. In this case \p BinOp is nullopt,
  /// \p InputTypeA represents the type being extended and \p OpAExtend the
  /// operation, i.e. sign- or zero-extend.
  /// For floating-point partial reductions, any fast math flags (FMF) should be
  /// provided to govern which reductions are valid to perform (depending on
  /// reassoc or contract, for example), whereas this must be nullopt for
  /// integer partial reductions.
  /// Also, \p InputTypeB should be nullptr and OpBExtend should be None.
  /// Alternatively, the second operand could be the result of a binary
  /// operation performed on two extends, i.e.
  ///   mul(zext i8 %a -> i32, zext i8 %b -> i32).
  /// In this case \p BinOp may specify the opcode of the binary operation,
  /// \p InputTypeA and \p InputTypeB the types being extended, and
  /// \p OpAExtend, \p OpBExtend the form of extensions. An example of an
  /// operation that uses a partial reduction is a dot product, which reduces
  /// two vectors in binary mul operation to another of 4 times fewer and 4
  /// times larger elements.
  LLVM_ABI InstructionCost getPartialReductionCost(
      unsigned Opcode, Type *InputTypeA, Type *InputTypeB, Type *AccumType,
      ElementCount VF, PartialReductionExtendKind OpAExtend,
      PartialReductionExtendKind OpBExtend, std::optional<unsigned> BinOp,
      TTI::TargetCostKind CostKind, std::optional<FastMathFlags> FMF) const;
 
  /// \return The maximum interleave factor that any transform should try to
  /// perform for this target. This number depends on the level of parallelism
  /// and the number of execution units in the CPU. HasUnorderedReductions
  /// specifies whether (unordered) reductions are present in the loop being
  /// vectorized.
  LLVM_ABI unsigned getMaxInterleaveFactor(ElementCount VF,
                                           bool HasUnorderedReductions) const;
 
  /// Collect properties of V used in cost analysis, e.g. OP_PowerOf2.
  LLVM_ABI static OperandValueInfo getOperandInfo(const Value *V);
 
  /// Return information about the vector formed for the specified index
  /// of a vector of (the same) instruction.
  LLVM_ABI static OperandValueInfo getOperandInfo(ArrayRef<Value *> Ops);
 
  /// Collect common data between two OperandValueInfo inputs
  LLVM_ABI static OperandValueInfo commonOperandInfo(const Value *X,
                                                     const Value *Y);
 
  /// This is an approximation of reciprocal throughput of a math/logic op.
  /// A higher cost indicates less expected throughput.
  /// From Agner Fog's guides, reciprocal throughput is "the average number of
  /// clock cycles per instruction when the instructions are not part of a
  /// limiting dependency chain."
  /// Therefore, costs should be scaled to account for multiple execution units
  /// on the target that can process this type of instruction. For example, if
  /// there are 5 scalar integer units and 2 vector integer units that can
  /// calculate an 'add' in a single cycle, this model should indicate that the
  /// cost of the vector add instruction is 2.5 times the cost of the scalar
  /// add instruction.
  /// \p Args is an optional argument which holds the instruction operands
  /// values so the TTI can analyze those values searching for special
  /// cases or optimizations based on those values.
  /// \p CtxI is the optional original context instruction, if one exists, to
  /// provide even more information.
  /// \p TLibInfo is used to search for platform specific vector library
  /// functions for instructions that might be converted to calls (e.g. frem).
  LLVM_ABI InstructionCost getArithmeticInstrCost(
      unsigned Opcode, Type *Ty, TTI::TargetCostKind CostKind,
      TTI::OperandValueInfo Opd1Info = {TTI::OK_AnyValue, TTI::OP_None},
      TTI::OperandValueInfo Opd2Info = {TTI::OK_AnyValue, TTI::OP_None},
      ArrayRef<const Value *> Args = {}, const Instruction *CtxI = nullptr,
      const TargetLibraryInfo *TLibInfo = nullptr) const;
 
  /// Returns the cost estimation for alternating opcode pattern that can be
  /// lowered to a single instruction on the target. In X86 this is for the
  /// addsub instruction which corrsponds to a Shuffle + Fadd + FSub pattern in
  /// IR. This function expects two opcodes: \p Opcode1 and \p Opcode2 being
  /// selected by \p OpcodeMask. The mask contains one bit per lane and is a `0`
  /// when \p Opcode0 is selected and `1` when Opcode1 is selected.
  /// \p VecTy is the vector type of the instruction to be generated.
  /// \p Scalars are the scalar instructions of the lanes, if known. The target
  /// may use them to find the patterns, which depend on the operands, like
  /// the alternating fused multiply-add.
  LLVM_ABI InstructionCost getAltInstrCost(
      VectorType *VecTy, unsigned Opcode0, unsigned Opcode1,
      const SmallBitVector &OpcodeMask, TTI::TargetCostKind CostKind,
      ArrayRef<const Value *> Scalars = {}) const;
 
  /// \return The cost of a shuffle instruction of kind Kind with inputs of type
  /// SrcTy, producing a vector of type DstTy. The exact mask may be passed as
  /// Mask, or else the array will be empty. The Index and SubTp parameters
  /// are used by the subvector insertions shuffle kinds to show the insert
  /// point and the type of the subvector being inserted. The operands of the
  /// shuffle can be passed through \p Args, which helps improve the cost
  /// estimation in some cases, like in broadcast loads.
  LLVM_ABI InstructionCost getShuffleCost(
      ShuffleKind Kind, VectorType *DstTy, VectorType *SrcTy,
      TTI::TargetCostKind CostKind, ArrayRef<int> Mask = {}, int Index = 0,
      VectorType *SubTp = nullptr, ArrayRef<const Value *> Args = {},
      const Instruction *CtxI = nullptr,
      TTI::VectorInstrContext VIC = TTI::VectorInstrContext::None) const;
 
  /// Represents a hint about the context in which a cast is used.
  ///
  /// For zext/sext, the context of the cast is the operand, which must be a
  /// load of some kind. For trunc, the context is of the cast is the single
  /// user of the instruction, which must be a store of some kind.
  ///
  /// This enum allows the vectorizer to give getCastInstrCost an idea of the
  /// type of cast it's dealing with, as not every cast is equal. For instance,
  /// the zext of a load may be free, but the zext of an interleaving load can
  //// be (very) expensive!
  ///
  /// See \c getCastContextHint to compute a CastContextHint from a cast
  /// Instruction*. Callers can use it if they don't need to override the
  /// context and just want it to be calculated from the instruction.
  ///
  /// FIXME: This handles the types of load/store that the vectorizer can
  /// produce, which are the cases where the context instruction is most
  /// likely to be incorrect. There are other situations where that can happen
  /// too, which might be handled here but in the long run a more general
  /// solution of costing multiple instructions at the same times may be better.
  enum class CastContextHint : uint8_t {
    None,          ///< The cast is not used with a load/store of any kind.
    Normal,        ///< The cast is used with a normal load/store.
    Masked,        ///< The cast is used with a masked load/store.
    GatherScatter, ///< The cast is used with a gather/scatter.
    Interleave,    ///< The cast is used with an interleaved load/store.
    Reversed,      ///< The cast is used with a reversed load/store.
  };
 
  /// Calculates a CastContextHint from \p I.
  /// This should be used by callers of getCastInstrCost if they wish to
  /// determine the context from some instruction.
  /// \returns the CastContextHint for ZExt/SExt/Trunc, None if \p I is nullptr,
  /// or if it's another type of cast.
  LLVM_ABI static CastContextHint getCastContextHint(const Instruction *I);
 
  /// \return The expected cost of cast instructions, such as bitcast, trunc,
  /// zext, etc. If there is an existing instruction that holds Opcode, it
  /// may be passed in the 'I' parameter.
  LLVM_ABI InstructionCost getCastInstrCost(
      unsigned Opcode, Type *Dst, Type *Src, TTI::CastContextHint CCH,
      TTI::TargetCostKind CostKind, const Instruction *I = nullptr) const;
 
  /// \return The expected cost of a sign- or zero-extended vector extract. Use
  /// Index = -1 to indicate that there is no information about the index value.
  LLVM_ABI InstructionCost
  getExtractWithExtendCost(unsigned Opcode, Type *Dst, VectorType *VecTy,
                           unsigned Index, TTI::TargetCostKind CostKind) const;
 
  /// \return The expected cost of control-flow related instructions such as
  /// Phi, Ret, Br, Switch.
  LLVM_ABI InstructionCost getCFInstrCost(unsigned Opcode,
                                          TTI::TargetCostKind CostKind,
                                          const Instruction *I = nullptr) const;
 
  /// \returns The expected cost of compare and select instructions. If there
  /// is an existing instruction that holds Opcode, it may be passed in the
  /// 'I' parameter. The \p VecPred parameter can be used to indicate the select
  /// is using a compare with the specified predicate as condition. When vector
  /// types are passed, \p VecPred must be used for all lanes.  For a
  /// comparison, the two operands are the natural values.  For a select, the
  /// two operands are the *value* operands, not the condition operand.
  LLVM_ABI InstructionCost
  getCmpSelInstrCost(unsigned Opcode, Type *ValTy, Type *CondTy,
                     CmpInst::Predicate VecPred, TTI::TargetCostKind CostKind,
                     OperandValueInfo Op1Info = {OK_AnyValue, OP_None},
                     OperandValueInfo Op2Info = {OK_AnyValue, OP_None},
                     const Instruction *I = nullptr) const;
 
  /// \return The expected cost of vector Insert and Extract.
  /// Use -1 to indicate that there is no information on the index value.
  /// This is used when the instruction is not available; a typical use
  /// case is to provision the cost of vectorization/scalarization in
  /// vectorizer passes.
  LLVM_ABI InstructionCost getVectorInstrCost(
      unsigned Opcode, Type *Val, TTI::TargetCostKind CostKind,
      unsigned Index = -1, const Value *Op0 = nullptr,
      const Value *Op1 = nullptr,
      TTI::VectorInstrContext VIC = TTI::VectorInstrContext::None) const;
 
  /// \return The expected cost of vector Insert and Extract.
  /// Use -1 to indicate that there is no information on the index value.
  /// This is used when the instruction is not available; a typical use
  /// case is to provision the cost of vectorization/scalarization in
  /// vectorizer passes.
  /// \param ScalarUserAndIdx encodes the information about extracts from a
  /// vector with 'Scalar' being the value being extracted,'User' being the user
  /// of the extract(nullptr if user is not known before vectorization) and
  /// 'Idx' being the extract lane.
  LLVM_ABI InstructionCost getVectorInstrCost(
      unsigned Opcode, Type *Val, TTI::TargetCostKind CostKind, unsigned Index,
      Value *Scalar,
      ArrayRef<std::tuple<Value *, User *, int>> ScalarUserAndIdx,
      TTI::VectorInstrContext VIC = TTI::VectorInstrContext::None) const;
 
  /// \return The expected cost of vector Insert and Extract.
  /// This is used when instruction is available, and implementation
  /// asserts 'I' is not nullptr.
  ///
  /// A typical suitable use case is cost estimation when vector instruction
  /// exists (e.g., from basic blocks during transformation).
  LLVM_ABI InstructionCost getVectorInstrCost(
      const Instruction &I, Type *Val, TTI::TargetCostKind CostKind,
      unsigned Index = -1,
      TTI::VectorInstrContext VIC = TTI::VectorInstrContext::None) const;
 
  /// \return The expected cost of inserting or extracting a lane that is \p
  /// Index elements from the end of a vector, i.e. the mathematical expression
  /// for the lane is (VF - 1 - Index). This is required for scalable vectors
  /// where the exact lane index is unknown at compile time.
  LLVM_ABI InstructionCost getIndexedVectorInstrCostFromEnd(
      unsigned Opcode, Type *Val, TTI::TargetCostKind CostKind,
      unsigned Index) const;
 
  /// \return The expected cost of aggregate inserts and extracts. This is
  /// used when the instruction is not available; a typical use case is to
  /// provision the cost of vectorization/scalarization in vectorizer passes.
  LLVM_ABI InstructionCost getInsertExtractValueCost(
      unsigned Opcode, TTI::TargetCostKind CostKind) const;
 
  /// \return The cost of replication shuffle of \p VF elements typed \p EltTy
  /// \p ReplicationFactor times.
  ///
  /// For example, the mask for \p ReplicationFactor=3 and \p VF=4 is:
  ///   <0,0,0,1,1,1,2,2,2,3,3,3>
  LLVM_ABI InstructionCost getReplicationShuffleCost(
      Type *EltTy, int ReplicationFactor, int VF, const APInt &DemandedDstElts,
      TTI::TargetCostKind CostKind) const;
 
  /// \return The cost of Load and Store instructions. The operand info
  /// \p OpdInfo should refer to the stored value for stores and the address
  /// for loads.
  LLVM_ABI InstructionCost
  getMemoryOpCost(unsigned Opcode, Type *Src, Align Alignment,
                  unsigned AddressSpace, TTI::TargetCostKind CostKind,
                  OperandValueInfo OpdInfo = {OK_AnyValue, OP_None},
                  const Instruction *I = nullptr) const;
 
  /// \return The cost of the interleaved memory operation.
  /// \p Opcode is the memory operation code
  /// \p VecTy is the vector type of the interleaved access.
  /// \p Factor is the interleave factor
  /// \p Indices is the indices for interleaved load members (as interleaved
  ///    load allows gaps)
  /// \p Alignment is the alignment of the memory operation
  /// \p AddressSpace is address space of the pointer.
  /// \p UseMaskForCond indicates if the memory access is predicated.
  /// \p UseMaskForGaps indicates if gaps should be masked.
  LLVM_ABI InstructionCost getInterleavedMemoryOpCost(
      unsigned Opcode, Type *VecTy, unsigned Factor, ArrayRef<unsigned> Indices,
      Align Alignment, unsigned AddressSpace, TTI::TargetCostKind CostKind,
      bool UseMaskForCond = false, bool UseMaskForGaps = false) const;
 
  /// A helper function to determine the type of reduction algorithm used
  /// for a given \p Opcode and set of FastMathFlags \p FMF.
  static bool requiresOrderedReduction(std::optional<FastMathFlags> FMF) {
    return FMF && !(*FMF).allowReassoc();
  }
 
  /// Calculate the cost of vector reduction intrinsics.
  ///
  /// This is the cost of reducing the vector value of type \p Ty to a scalar
  /// value using the operation denoted by \p Opcode. The FastMathFlags
  /// parameter \p FMF indicates what type of reduction we are performing:
  ///   1. Tree-wise. This is the typical 'fast' reduction performed that
  ///   involves successively splitting a vector into half and doing the
  ///   operation on the pair of halves until you have a scalar value. For
  ///   example:
  ///     (v0, v1, v2, v3)
  ///     ((v0+v2), (v1+v3), undef, undef)
  ///     ((v0+v2+v1+v3), undef, undef, undef)
  ///   This is the default behaviour for integer operations, whereas for
  ///   floating point we only do this if \p FMF indicates that
  ///   reassociation is allowed.
  ///   2. Ordered. For a vector with N elements this involves performing N
  ///   operations in lane order, starting with an initial scalar value, i.e.
  ///     result = InitVal + v0
  ///     result = result + v1
  ///     result = result + v2
  ///     result = result + v3
  ///   This is only the case for FP operations and when reassociation is not
  ///   allowed.
  ///
  LLVM_ABI InstructionCost getArithmeticReductionCost(
      unsigned Opcode, VectorType *Ty, std::optional<FastMathFlags> FMF,
      TTI::TargetCostKind CostKind) const;
 
  LLVM_ABI InstructionCost
  getMinMaxReductionCost(Intrinsic::ID IID, VectorType *Ty, FastMathFlags FMF,
                         TTI::TargetCostKind CostKind) const;
 
  /// Calculate the cost of an extended reduction pattern, similar to
  /// getArithmeticReductionCost of an Add/Sub reduction with multiply and
  /// optional extensions. This is the cost of as:
  /// * ResTy vecreduce.add/sub(mul (A, B)) or,
  /// * ResTy vecreduce.add/sub(mul(ext(Ty A), ext(Ty B)).
  LLVM_ABI InstructionCost
  getMulAccReductionCost(bool IsUnsigned, unsigned RedOpcode, Type *ResTy,
                         VectorType *Ty, TTI::TargetCostKind CostKind) const;
 
  /// Calculate the cost of an extended reduction pattern, similar to
  /// getArithmeticReductionCost of a reduction with an extension.
  /// This is the cost of as:
  /// ResTy vecreduce.opcode(ext(Ty A)).
  LLVM_ABI InstructionCost getExtendedReductionCost(
      unsigned Opcode, bool IsUnsigned, Type *ResTy, VectorType *Ty,
      std::optional<FastMathFlags> FMF, TTI::TargetCostKind CostKind) const;
 
  /// \returns The cost of Intrinsic instructions. Analyses the real arguments.
  /// Three cases are handled: 1. scalar instruction 2. vector instruction
  /// 3. scalar instruction which is to be vectorized.
  LLVM_ABI InstructionCost getIntrinsicInstrCost(
      const IntrinsicCostAttributes &ICA, TTI::TargetCostKind CostKind) const;
 
  /// \returns The cost of memory intrinsic instructions.
  /// Used when IntrinsicInst is not materialized.
  LLVM_ABI InstructionCost
  getMemIntrinsicInstrCost(const MemIntrinsicCostAttributes &MICA,
                           TTI::TargetCostKind CostKind) const;
 
  /// \returns The cost of Call instructions.
  LLVM_ABI InstructionCost getCallInstrCost(Function *F, Type *RetTy,
                                            ArrayRef<Type *> Tys,
                                            TTI::TargetCostKind CostKind) const;
 
  /// \returns The number of pieces into which the provided type must be
  /// split during legalization. Zero is returned when the answer is unknown.
  LLVM_ABI unsigned getNumberOfParts(Type *Tp) const;
 
  /// \returns The cost of the address computation. For most targets this can be
  /// merged into the instruction indexing mode. Some targets might want to
  /// distinguish between address computation for memory operations with vector
  /// pointer types and scalar pointer types. Such targets should override this
  /// function. \p SE holds the pointer for the scalar evolution object which
  /// was used in order to get the Ptr step value. \p Ptr holds the SCEV of the
  /// access pointer.
  LLVM_ABI InstructionCost
  getAddressComputationCost(Type *PtrTy, ScalarEvolution *SE, const SCEV *Ptr,
                            TTI::TargetCostKind CostKind) const;
 
  /// \returns The cost, if any, of keeping values of the given types alive
  /// over a callsite.
  ///
  /// Some types may require the use of register classes that do not have
  /// any callee-saved registers, so would require a spill and fill.
  LLVM_ABI InstructionCost
  getCostOfKeepingLiveOverCall(ArrayRef<Type *> Tys) const;
 
  /// \returns True if the intrinsic is a supported memory intrinsic.  Info
  /// will contain additional information - whether the intrinsic may write
  /// or read to memory, volatility and the pointer.  Info is undefined
  /// if false is returned.
  LLVM_ABI bool getTgtMemIntrinsic(IntrinsicInst *Inst,
                                   MemIntrinsicInfo &Info) const;
 
  /// \returns The maximum element size, in bytes, for an element
  /// unordered-atomic memory intrinsic.
  LLVM_ABI unsigned getAtomicMemIntrinsicMaxElementSize() const;
 
  /// \returns A value which is the result of the given memory intrinsic. If \p
  /// CanCreate is true, new instructions may be created to extract the result
  /// from the given intrinsic memory operation. Returns nullptr if the target
  /// cannot create a result from the given intrinsic.
  LLVM_ABI Value *
  getOrCreateResultFromMemIntrinsic(IntrinsicInst *Inst, Type *ExpectedType,
                                    bool CanCreate = true) const;
 
  /// \returns The type to use in a loop expansion of a memcpy call.
  LLVM_ABI Type *getMemcpyLoopLoweringType(
      LLVMContext &Context, Value *Length, unsigned SrcAddrSpace,
      unsigned DestAddrSpace, Align SrcAlign, Align DestAlign,
      std::optional<uint32_t> AtomicElementSize = std::nullopt) const;
 
  /// \param[out] OpsOut The operand types to copy RemainingBytes of memory.
  /// \param RemainingBytes The number of bytes to copy.
  ///
  /// Calculates the operand types to use when copying \p RemainingBytes of
  /// memory, where source and destination alignments are \p SrcAlign and
  /// \p DestAlign respectively.
  LLVM_ABI void getMemcpyLoopResidualLoweringType(
      SmallVectorImpl<Type *> &OpsOut, LLVMContext &Context,
      unsigned RemainingBytes, unsigned SrcAddrSpace, unsigned DestAddrSpace,
      Align SrcAlign, Align DestAlign,
      std::optional<uint32_t> AtomicCpySize = std::nullopt) const;
 
  /// \returns True if the two functions have compatible attributes for inlining
  /// purposes.
  LLVM_ABI bool areInlineCompatible(const Function *Caller,
                                    const Function *Callee) const;
 
  /// Returns a penalty for invoking call \p Call in \p F.
  /// For example, if a function F calls a function G, which in turn calls
  /// function H, then getInlineCallPenalty(F, H()) would return the
  /// penalty of calling H from F, e.g. after inlining G into F.
  /// \p DefaultCallPenalty is passed to give a default penalty that
  /// the target can amend or override.
  LLVM_ABI unsigned getInlineCallPenalty(const Function *F,
                                         const CallBase &Call,
                                         unsigned DefaultCallPenalty) const;
 
  /// \returns true if `Caller`'s `Attr` should be added to the new function
  /// created by outlining part of `Caller`.
  LLVM_ABI bool
  shouldCopyAttributeWhenOutliningFrom(const Function *Caller,
                                       const Attribute &Attr) const;
 
  /// \returns True if the caller and callee agree on how \p Types will be
  /// passed to or returned from the callee.
  /// to the callee.
  /// \param Types List of types to check.
  LLVM_ABI bool areTypesABICompatible(const Function *Caller,
                                      const Function *Callee,
                                      ArrayRef<Type *> Types) const;
 
  /// The type of load/store indexing.
  enum MemIndexedMode {
    MIM_Unindexed, ///< No indexing.
    MIM_PreInc,    ///< Pre-incrementing.
    MIM_PreDec,    ///< Pre-decrementing.
    MIM_PostInc,   ///< Post-incrementing.
    MIM_PostDec    ///< Post-decrementing.
  };
 
  /// \returns True if the specified indexed load for the given type is legal.
  LLVM_ABI bool isIndexedLoadLegal(enum MemIndexedMode Mode, Type *Ty) const;
 
  /// \returns True if the specified indexed store for the given type is legal.
  LLVM_ABI bool isIndexedStoreLegal(enum MemIndexedMode Mode, Type *Ty) const;
 
  /// \returns The bitwidth of the largest vector type that should be used to
  /// load/store in the given address space.
  LLVM_ABI unsigned getLoadStoreVecRegBitWidth(unsigned AddrSpace) const;
 
  /// \returns True if the load instruction is legal to vectorize.
  LLVM_ABI bool isLegalToVectorizeLoad(LoadInst *LI) const;
 
  /// \returns True if the store instruction is legal to vectorize.
  LLVM_ABI bool isLegalToVectorizeStore(StoreInst *SI) const;
 
  /// \returns True if it is legal to vectorize the given load chain.
  LLVM_ABI bool isLegalToVectorizeLoadChain(unsigned ChainSizeInBytes,
                                            Align Alignment,
                                            unsigned AddrSpace) const;
 
  /// \returns True if it is legal to vectorize the given store chain.
  LLVM_ABI bool isLegalToVectorizeStoreChain(unsigned ChainSizeInBytes,
                                             Align Alignment,
                                             unsigned AddrSpace) const;
 
  /// \returns True if it is legal to vectorize the given reduction kind.
  LLVM_ABI bool isLegalToVectorizeReduction(const RecurrenceDescriptor &RdxDesc,
                                            ElementCount VF) const;
 
  /// \returns True if the given type is supported for scalable vectors
  LLVM_ABI bool isElementTypeLegalForScalableVector(Type *Ty) const;
 
  /// \returns The new vector factor value if the target doesn't support \p
  /// SizeInBytes loads or has a better vector factor.
  LLVM_ABI unsigned getLoadVectorFactor(unsigned VF, unsigned LoadSize,
                                        unsigned ChainSizeInBytes,
                                        VectorType *VecTy) const;
 
  /// \returns The new vector factor value if the target doesn't support \p
  /// SizeInBytes stores or has a better vector factor.
  LLVM_ABI unsigned getStoreVectorFactor(unsigned VF, unsigned StoreSize,
                                         unsigned ChainSizeInBytes,
                                         VectorType *VecTy) const;
 
  /// \returns True if the target prefers fixed width vectorization if the
  /// loop vectorizer's cost-model assigns an equal cost to the fixed and
  /// scalable version of the vectorized loop.
  LLVM_ABI bool preferFixedOverScalableIfEqualCost() const;
 
  /// \returns True if target prefers SLP vectorizer with altermate opcode
  /// vectorization, false - otherwise.
  LLVM_ABI bool preferAlternateOpcodeVectorization() const;
 
  /// \returns True if the SLP vectorizer should apply the instruction-count
  /// check that rejects 2-element vector trees when the vector instruction
  /// count exceeds the scalar instruction count, false if the target opts out
  /// of this heuristic.
  LLVM_ABI bool preferSLPInstCountCheck() const;
 
  /// \returns True if the target prefers reductions of \p Kind to be performed
  /// in the loop.
  LLVM_ABI bool preferInLoopReduction(RecurKind Kind, Type *Ty) const;
 
  /// \returns True if the target prefers reductions select kept in the loop
  /// when tail folding. i.e.
  /// loop:
  ///   p = phi (0, s)
  ///   a = add (p, x)
  ///   s = select (mask, a, p)
  /// vecreduce.add(s)
  ///
  /// As opposed to the normal scheme of p = phi (0, a) which allows the select
  /// to be pulled out of the loop. If the select(.., add, ..) can be predicated
  /// by the target, this can lead to cleaner code generation.
  LLVM_ABI bool preferPredicatedReductionSelect() const;
 
  /// Return true if the loop vectorizer should consider vectorizing an
  /// otherwise scalar epilogue loop if the loop already has been vectorized
  /// processing \p Iters scalar iterations per vector iteration.
  LLVM_ABI bool preferEpilogueVectorization(ElementCount Iters) const;
 
  /// \returns True if the loop vectorizer should discard any VFs where the
  /// maximum register pressure exceeds getNumberOfRegisters.
  LLVM_ABI bool shouldConsiderVectorizationRegPressure() const;
 
  /// \returns True if the target wants to expand the given reduction intrinsic
  /// into a shuffle sequence.
  LLVM_ABI bool shouldExpandReduction(const IntrinsicInst *II) const;
 
  enum struct ReductionShuffle { SplitHalf, Pairwise };
 
  /// \returns The shuffle sequence pattern used to expand the given reduction
  /// intrinsic.
  LLVM_ABI ReductionShuffle
  getPreferredExpandedReductionShuffle(const IntrinsicInst *II) const;
 
  /// \returns the size cost of rematerializing a GlobalValue address relative
  /// to a stack reload.
  LLVM_ABI unsigned getGISelRematGlobalCost() const;
 
  /// \returns the lower bound of a trip count to decide on vectorization
  /// while tail-folding.
  LLVM_ABI unsigned getMinTripCountTailFoldingThreshold() const;
 
  /// \returns True if the target supports scalable vectors.
  LLVM_ABI bool supportsScalableVectors() const;
 
  /// \return true when scalable vectorization is preferred.
  LLVM_ABI bool enableScalableVectorization() const;
 
  /// \name Vector Predication Information
  /// @{
  /// Whether the target supports the %evl parameter of VP intrinsic efficiently
  /// in hardware. (see LLVM Language Reference - "Vector Predication
  /// Intrinsics"). Use of %evl is discouraged when that is not the case.
  LLVM_ABI bool hasActiveVectorLength() const;
 
  /// Return true if sinking I's operands to the same basic block as I is
  /// profitable, e.g. because the operands can be folded into a target
  /// instruction during instruction selection. After calling the function
  /// \p Ops contains the Uses to sink ordered by dominance (dominating users
  /// come first). \p LI, when available, lets targets account for loop
  /// boundaries when deciding profitability.
  LLVM_ABI bool isProfitableToSinkOperands(Instruction *I,
                                           SmallVectorImpl<Use *> &Ops,
                                           const LoopInfo *LI = nullptr) const;
 
  /// Return true if it's significantly cheaper to shift a vector by a uniform
  /// scalar than by an amount which will vary across each lane. On x86 before
  /// AVX2 for example, there is a "psllw" instruction for the former case, but
  /// no simple instruction for a general "a << b" operation on vectors.
  /// This should also apply to lowering for vector funnel shifts (rotates).
  LLVM_ABI bool isVectorShiftByScalarCheap(Type *Ty) const;
 
  struct VPLegalization {
    enum VPTransform {
      // keep the predicating parameter
      Legal = 0,
      // where legal, discard the predicate parameter
      Discard = 1,
      // transform into something else that is also predicating
      Convert = 2
    };
 
    // How to transform the EVL parameter.
    // Legal:   keep the EVL parameter as it is.
    // Discard: Ignore the EVL parameter where it is safe to do so.
    // Convert: Fold the EVL into the mask parameter.
    VPTransform EVLParamStrategy;
 
    // How to transform the operator.
    // Legal:   The target supports this operator.
    // Convert: Convert this to a non-VP operation.
    // The 'Discard' strategy is invalid.
    VPTransform OpStrategy;
 
    bool shouldDoNothing() const {
      return (EVLParamStrategy == Legal) && (OpStrategy == Legal);
    }
    VPLegalization(VPTransform EVLParamStrategy, VPTransform OpStrategy)
        : EVLParamStrategy(EVLParamStrategy), OpStrategy(OpStrategy) {}
  };
 
  /// \returns How the target needs this vector-predicated operation to be
  /// transformed.
  LLVM_ABI VPLegalization
  getVPLegalizationStrategy(const VPIntrinsic &PI) const;
  /// @}
 
  /// \returns Whether a 32-bit branch instruction is available in Arm or Thumb
  /// state.
  ///
  /// Used by the LowerTypeTests pass, which constructs an IR inline assembler
  /// node containing a jump table in a format suitable for the target, so it
  /// needs to know what format of jump table it can legally use.
  ///
  /// For non-Arm targets, this function isn't used. It defaults to returning
  /// false, but it shouldn't matter what it returns anyway.
  LLVM_ABI bool hasArmWideBranch(bool Thumb) const;
 
  /// Returns a bitmask constructed from the target-features or fmv-features
  /// metadata of a function corresponding to its Arch Extensions.
  LLVM_ABI APInt getFeatureMask(const Function &F) const;
 
  /// Returns a bitmask constructed from the target-features or fmv-features
  /// metadata of a function corresponding to its FMV priority.
  LLVM_ABI APInt getPriorityMask(const Function &F) const;
 
  /// Returns true if this is an instance of a function with multiple versions.
  LLVM_ABI bool isMultiversionedFunction(const Function &F) const;
 
  /// \return The maximum number of function arguments the target supports.
  LLVM_ABI unsigned getMaxNumArgs() const;
 
  /// @}
 
  /// Collect kernel launch bounds for \p F into \p LB.
  LLVM_ABI void collectKernelLaunchBounds(
      const Function &F,
      SmallVectorImpl<std::pair<StringRef, int64_t>> &LB) const;
 
  /// Returns true if GEP should not be used to index into vectors for this
  /// target.
  LLVM_ABI bool allowVectorElementIndexingUsingGEP() const;
 
  /// Determine if an instruction with Custom uniformity can be proven uniform
  /// based on which operands are uniform.
  ///
  /// \param I The instruction to check.
  /// \param UniformArgs A bitvector indicating which operands are known to be
  ///                    uniform (bit N corresponds to operand N).
  /// \returns true if the instruction result can be proven uniform given the
  ///          uniform operands, false otherwise.
  LLVM_ABI bool isUniform(const Instruction *I,
                          const SmallBitVector &UniformArgs) const;
 
private:
  std::unique_ptr<const TargetTransformInfoImplBase> TTIImpl;
};
 
/// Costs for each cost kind in a target cost table. Field order matches
/// TargetCostKind, since table entries initialize these fields positionally.
/// A cost of ~0U means the table provides no cost for that kind.
struct CostKindCosts {
  unsigned RecipThroughputCost = ~0U;
  unsigned LatencyCost = ~0U;
  unsigned CodeSizeCost = ~0U;
  unsigned SizeAndLatencyCost = ~0U;
 
  std::optional<unsigned>
  operator[](TargetTransformInfo::TargetCostKind Kind) const {
    unsigned Cost = ~0U;
    switch (Kind) {
    case TargetTransformInfo::TCK_RecipThroughput:
      Cost = RecipThroughputCost;
      break;
    case TargetTransformInfo::TCK_Latency:
      Cost = LatencyCost;
      break;
    case TargetTransformInfo::TCK_CodeSize:
      Cost = CodeSizeCost;
      break;
    case TargetTransformInfo::TCK_SizeAndLatency:
      Cost = SizeAndLatencyCost;
      break;
    }
    if (Cost == ~0U)
      return std::nullopt;
    return Cost;
  }
};
 
/// Analysis pass providing the \c TargetTransformInfo.
///
/// The core idea of the TargetIRAnalysis is to expose an interface through
/// which LLVM targets can analyze and provide information about the middle
/// end's target-independent IR. This supports use cases such as target-aware
/// cost modeling of IR constructs.
///
/// This is a function analysis because much of the cost modeling for targets
/// is done in a subtarget specific way and LLVM supports compiling different
/// functions targeting different subtargets in order to support runtime
/// dispatch according to the observed subtarget.
class TargetIRAnalysis : public AnalysisInfoMixin<TargetIRAnalysis> {
public:
  typedef TargetTransformInfo Result;
 
  /// Default construct a target IR analysis.
  ///
  /// This will use the module's datalayout to construct a baseline
  /// conservative TTI result.
  LLVM_ABI TargetIRAnalysis();
 
  /// Construct an IR analysis pass around a target-provide callback.
  ///
  /// The callback will be called with a particular function for which the TTI
  /// is needed and must return a TTI object for that function.
  LLVM_ABI
  TargetIRAnalysis(std::function<Result(const Function &)> TTICallback);
 
  // Value semantics. We spell out the constructors for MSVC.
  TargetIRAnalysis(const TargetIRAnalysis &Arg)
      : TTICallback(Arg.TTICallback) {}
  TargetIRAnalysis(TargetIRAnalysis &&Arg)
      : TTICallback(std::move(Arg.TTICallback)) {}
  TargetIRAnalysis &operator=(const TargetIRAnalysis &RHS) {
    TTICallback = RHS.TTICallback;
    return *this;
  }
  TargetIRAnalysis &operator=(TargetIRAnalysis &&RHS) {
    TTICallback = std::move(RHS.TTICallback);
    return *this;
  }
 
  LLVM_ABI Result run(const Function &F, FunctionAnalysisManager &);
 
private:
  friend AnalysisInfoMixin<TargetIRAnalysis>;
  LLVM_ABI static AnalysisKey Key;
 
  /// The callback used to produce a result.
  ///
  /// We use a completely opaque callback so that targets can provide whatever
  /// mechanism they desire for constructing the TTI for a given function.
  ///
  /// FIXME: Should we really use std::function? It's relatively inefficient.
  /// It might be possible to arrange for even stateful callbacks to outlive
  /// the analysis and thus use a function_ref which would be lighter weight.
  /// This may also be less error prone as the callback is likely to reference
  /// the external TargetMachine, and that reference needs to never dangle.
  std::function<Result(const Function &)> TTICallback;
 
  /// Helper function used as the callback in the default constructor.
  static Result getDefaultTTI(const Function &F);
};
 
/// Wrapper pass for TargetTransformInfo.
///
/// This pass can be constructed from a TTI object which it stores internally
/// and is queried by passes.
class LLVM_ABI TargetTransformInfoWrapperPass : public ImmutablePass {
  TargetIRAnalysis TIRA;
  std::optional<TargetTransformInfo> TTI;
 
  virtual void anchor();
 
public:
  static char ID;
 
  /// We must provide a default constructor for the pass but it should
  /// never be used.
  ///
  /// Use the constructor below or call one of the creation routines.
  TargetTransformInfoWrapperPass();
 
  explicit TargetTransformInfoWrapperPass(TargetIRAnalysis TIRA);
 
  TargetTransformInfo &getTTI(const Function &F);
};
 
/// Create an analysis pass wrapper around a TTI object.
///
/// This analysis pass just holds the TTI instance and makes it available to
/// clients.
LLVM_ABI ImmutablePass *
createTargetTransformInfoWrapperPass(TargetIRAnalysis TIRA);
 
} // namespace llvm
 
#endif