SelectionDAG.h

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//===- llvm/CodeGen/SelectionDAG.h - InstSelection DAG ----------*- 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
//
//===----------------------------------------------------------------------===//
//
// This file declares the SelectionDAG class, and transitively defines the
// SDNode class and subclasses.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_CODEGEN_SELECTIONDAG_H
#define LLVM_CODEGEN_SELECTIONDAG_H
 
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/ilist.h"
#include "llvm/ADT/iterator.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/CodeGen/DAGCombine.h"
#include "llvm/CodeGen/ISDOpcodes.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachinePassManager.h"
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/CodeGenTypes/MachineValueType.h"
#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/RuntimeLibcalls.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/ArrayRecycler.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/KnownFPClass.h"
#include "llvm/Support/RecyclingAllocator.h"
#include "llvm/Support/UndefPoison.h"
#include <cassert>
#include <cstdint>
#include <functional>
#include <map>
#include <set>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
 
namespace llvm {
 
class DIExpression;
class DILabel;
class DIVariable;
class Function;
class Pass;
class Type;
template <class GraphType> struct GraphTraits;
template <typename T, unsigned int N> class SmallSetVector;
template <typename T, typename Enable> struct FoldingSetTrait;
class BatchAAResults;
class BlockAddress;
class BlockFrequencyInfo;
class Constant;
class ConstantFP;
class ConstantInt;
class DataLayout;
struct fltSemantics;
class FunctionLoweringInfo;
class FunctionVarLocs;
class GlobalValue;
struct KnownBits;
class LLVMContext;
class MachineBasicBlock;
class MachineConstantPoolValue;
class MCSymbol;
class ProfileSummaryInfo;
class SDDbgValue;
class SDDbgOperand;
class SDDbgLabel;
class SelectionDAG;
class SelectionDAGTargetInfo;
class TargetLibraryInfo;
class TargetLowering;
class TargetMachine;
class TargetSubtargetInfo;
class Value;
 
template <typename T> class GenericSSAContext;
using SSAContext = GenericSSAContext<Function>;
template <typename T> class GenericUniformityInfo;
using UniformityInfo = GenericUniformityInfo<SSAContext>;
 
/// The key SelectionDAG uniques SDNodes by.  \p Tail carries the opcode
/// specific data, which most opcodes do not have, still serialized; a lookup
/// site appends it through the FoldingSetNodeID-shaped forwarders below.
struct SDNodeKey {
  unsigned Opcode;
  const EVT *VTs;
  ArrayRef<SDValue> Ops;
  FoldingSetNodeID Tail;
  /// Backs \p Ops when the key is built from a node; empty otherwise.  No
  /// inline capacity: only that one path pays for the storage.
  SmallVector<SDValue, 0> OpStorage;
 
  SDNodeKey(unsigned Opcode, SDVTList VTList, ArrayRef<SDValue> Ops)
      : Opcode(Opcode), VTs(VTList.VTs), Ops(Ops) {}
  LLVM_ABI explicit SDNodeKey(const SDNode &N);
 
  SDNodeKey(const SDNodeKey &) = delete;
  SDNodeKey &operator=(const SDNodeKey &) = delete;
 
  // Forward to FoldingSetNodeID's own overload set, so a lookup site resolves
  // the same way it did when profiling into one.
  template <typename T> void AddInteger(T I) { Tail.AddInteger(I); }
  void AddBoolean(bool B) { Tail.AddBoolean(B); }
  void AddPointer(const void *P) { Tail.AddPointer(P); }
};
 
struct SDNodeKeyInfo {
  using KeyTy = SDNodeKey;
 
  static KeyTy getKey(const SDNode &N) { return SDNodeKey(N); }
 
  static unsigned getHashValue(const KeyTy &Key) {
    unsigned H = detail::combineHashValue(
        Key.Opcode, DenseMapInfo<const EVT *>::getHashValue(Key.VTs));
    for (const SDValue &Op : Key.Ops)
      H = detail::combineHashValue(H, DenseMapInfo<SDValue>::getHashValue(Op));
    for (unsigned Word : Key.Tail.getRef())
      H = detail::combineHashValue(H, Word);
    return H;
  }
 
  LLVM_ABI static bool isEqual(const KeyTy &Key, const SDNode &N);
};
 
template <> struct ilist_alloc_traits<SDNode> {
  static void deleteNode(SDNode *) {
    llvm_unreachable("ilist_traits<SDNode> shouldn't see a deleteNode call!");
  }
};
 
/// Keeps track of dbg_value information through SDISel.  We do
/// not build SDNodes for these so as not to perturb the generated code;
/// instead the info is kept off to the side in this structure. Each SDNode may
/// have one or more associated dbg_value entries. This information is kept in
/// DbgValMap.
/// Byval parameters are handled separately because they don't use alloca's,
/// which busts the normal mechanism.  There is good reason for handling all
/// parameters separately:  they may not have code generated for them, they
/// should always go at the beginning of the function regardless of other code
/// motion, and debug info for them is potentially useful even if the parameter
/// is unused.  Right now only byval parameters are handled separately.
class SDDbgInfo {
  BumpPtrAllocator Alloc;
  SmallVector<SDDbgValue*, 32> DbgValues;
  SmallVector<SDDbgValue*, 32> ByvalParmDbgValues;
  SmallVector<SDDbgLabel*, 4> DbgLabels;
  using DbgValMapType = DenseMap<const SDNode *, SmallVector<SDDbgValue *, 2>>;
  DbgValMapType DbgValMap;
 
public:
  SDDbgInfo() = default;
  SDDbgInfo(const SDDbgInfo &) = delete;
  SDDbgInfo &operator=(const SDDbgInfo &) = delete;
 
  LLVM_ABI void add(SDDbgValue *V, bool isParameter);
 
  void add(SDDbgLabel *L) { DbgLabels.push_back(L); }
 
  /// Invalidate all DbgValues attached to the node and remove
  /// it from the Node-to-DbgValues map.
  LLVM_ABI void erase(const SDNode *Node);
 
  void clear() {
    DbgValMap.clear();
    DbgValues.clear();
    ByvalParmDbgValues.clear();
    DbgLabels.clear();
    Alloc.Reset();
  }
 
  BumpPtrAllocator &getAlloc() { return Alloc; }
 
  bool empty() const {
    return DbgValues.empty() && ByvalParmDbgValues.empty() && DbgLabels.empty();
  }
 
  ArrayRef<SDDbgValue*> getSDDbgValues(const SDNode *Node) const {
    auto I = DbgValMap.find(Node);
    if (I != DbgValMap.end())
      return I->second;
    return ArrayRef<SDDbgValue*>();
  }
 
  using DbgIterator = SmallVectorImpl<SDDbgValue*>::iterator;
  using DbgLabelIterator = SmallVectorImpl<SDDbgLabel*>::iterator;
 
  DbgIterator DbgBegin() { return DbgValues.begin(); }
  DbgIterator DbgEnd()   { return DbgValues.end(); }
  DbgIterator ByvalParmDbgBegin() { return ByvalParmDbgValues.begin(); }
  DbgIterator ByvalParmDbgEnd()   { return ByvalParmDbgValues.end(); }
  DbgLabelIterator DbgLabelBegin() { return DbgLabels.begin(); }
  DbgLabelIterator DbgLabelEnd()   { return DbgLabels.end(); }
};
 
LLVM_ABI void checkForCycles(const SelectionDAG *DAG, bool force = false);
 
/// This is used to represent a portion of an LLVM function in a low-level
/// Data Dependence DAG representation suitable for instruction selection.
/// This DAG is constructed as the first step of instruction selection in order
/// to allow implementation of machine specific optimizations
/// and code simplifications.
///
/// The representation used by the SelectionDAG is a target-independent
/// representation, which has some similarities to the GCC RTL representation,
/// but is significantly more simple, powerful, and is a graph form instead of a
/// linear form.
///
class SelectionDAG {
  const TargetMachine &TM;
  const SelectionDAGTargetInfo *TSI = nullptr;
  const TargetLowering *TLI = nullptr;
  const TargetLibraryInfo *LibInfo = nullptr;
  const LibcallLoweringInfo *Libcalls = nullptr;
 
  const FunctionVarLocs *FnVarLocs = nullptr;
  MachineFunction *MF;
  MachineFunctionAnalysisManager *MFAM = nullptr;
  LLVMContext *Context;
  CodeGenOptLevel OptLevel;
 
  UniformityInfo *UA = nullptr;
  FunctionLoweringInfo * FLI = nullptr;
 
  ProfileSummaryInfo *PSI = nullptr;
  BlockFrequencyInfo *BFI = nullptr;
 
  /// Uniquing of VT lists.  Each key aliases the EVT array that the returned
  /// SDVTList points at, allocated from \p Allocator.
  struct VTListInfo {
    static unsigned getHashValue(ArrayRef<EVT> VTs) {
      unsigned H = VTs.size();
      for (EVT VT : VTs)
        H = detail::combineHashValue(
            H, DenseMapInfo<intptr_t>::getHashValue(VT.getRawBits()));
      return H;
    }
    static bool isEqual(ArrayRef<EVT> LHS, ArrayRef<EVT> RHS) {
      return LHS == RHS;
    }
  };
  DenseSet<ArrayRef<EVT>, VTListInfo> VTLists;
 
  /// Pool allocation for misc. objects that are created once per SelectionDAG.
  BumpPtrAllocator Allocator;
 
  /// The starting token.
  SDNode EntryNode;
 
  /// The root of the entire DAG.
  SDValue Root;
 
  /// A linked list of nodes in the current DAG.
  ilist<SDNode> AllNodes;
 
  /// The AllocatorType for allocating SDNodes. We use
  /// pool allocation with recycling.
  using NodeAllocatorType = RecyclingAllocator<BumpPtrAllocator, SDNode,
                                               sizeof(LargestSDNode),
                                               alignof(MostAlignedSDNode)>;
 
  /// Pool allocation for nodes.
  NodeAllocatorType NodeAllocator;
 
  /// This structure is used to memoize nodes, automatically performing
  /// CSE with existing nodes when a duplicate is requested.
  UniquingSet<SDNode, SDNodeKeyInfo> CSEMap;
 
  /// Pool allocation for machine-opcode SDNode operands.
  BumpPtrAllocator OperandAllocator;
  ArrayRecycler<SDUse> OperandRecycler;
 
  /// Tracks dbg_value and dbg_label information through SDISel.
  SDDbgInfo *DbgInfo;
 
  using CallSiteInfo = MachineFunction::CallSiteInfo;
  using CalledGlobalInfo = MachineFunction::CalledGlobalInfo;
 
  struct NodeExtraInfo {
    CallSiteInfo CSInfo;
    MDNode *HeapAllocSite = nullptr;
    MDNode *PCSections = nullptr;
    MDNode *MMRA = nullptr;
    CalledGlobalInfo CalledGlobal{};
    bool NoMerge = false;
  };
  /// Out-of-line extra information for SDNodes.
  DenseMap<const SDNode *, NodeExtraInfo> SDEI;
 
  /// PersistentId counter to be used when inserting the next
  /// SDNode to this SelectionDAG. We do not place that under
  /// `#if LLVM_ENABLE_ABI_BREAKING_CHECKS` intentionally because
  /// it adds unneeded complexity without noticeable
  /// benefits (see discussion with @thakis in D120714).
  uint16_t NextPersistentId = 0;
 
public:
  /// Clients of various APIs that cause global effects on
  /// the DAG can optionally implement this interface.  This allows the clients
  /// to handle the various sorts of updates that happen.
  ///
  /// A DAGUpdateListener automatically registers itself with DAG when it is
  /// constructed, and removes itself when destroyed in RAII fashion.
  struct LLVM_ABI DAGUpdateListener {
    DAGUpdateListener *const Next;
    SelectionDAG &DAG;
 
    explicit DAGUpdateListener(SelectionDAG &D)
      : Next(D.UpdateListeners), DAG(D) {
      DAG.UpdateListeners = this;
    }
 
    virtual ~DAGUpdateListener() {
      assert(DAG.UpdateListeners == this &&
             "DAGUpdateListeners must be destroyed in LIFO order");
      DAG.UpdateListeners = Next;
    }
 
    /// The node N that was deleted and, if E is not null, an
    /// equivalent node E that replaced it.
    virtual void NodeDeleted(SDNode *N, SDNode *E);
 
    /// The node N that was updated.
    virtual void NodeUpdated(SDNode *N);
 
    /// The node N that was inserted.
    virtual void NodeInserted(SDNode *N);
  };
 
  struct LLVM_ABI DAGNodeDeletedListener : public DAGUpdateListener {
    std::function<void(SDNode *, SDNode *)> Callback;
 
    DAGNodeDeletedListener(SelectionDAG &DAG,
                           std::function<void(SDNode *, SDNode *)> Callback)
        : DAGUpdateListener(DAG), Callback(std::move(Callback)) {}
 
    void NodeDeleted(SDNode *N, SDNode *E) override { Callback(N, E); }
 
   private:
    virtual void anchor();
  };
 
  struct LLVM_ABI DAGNodeInsertedListener : public DAGUpdateListener {
    std::function<void(SDNode *)> Callback;
 
    DAGNodeInsertedListener(SelectionDAG &DAG,
                            std::function<void(SDNode *)> Callback)
        : DAGUpdateListener(DAG), Callback(std::move(Callback)) {}
 
    void NodeInserted(SDNode *N) override { Callback(N); }
 
  private:
    virtual void anchor();
  };
 
  /// Help to insert SDNodeFlags automatically in transforming. Use
  /// RAII to save and resume flags in current scope.
  class FlagInserter {
    SelectionDAG &DAG;
    SDNodeFlags Flags;
    FlagInserter *LastInserter;
 
  public:
    FlagInserter(SelectionDAG &SDAG, SDNodeFlags Flags)
        : DAG(SDAG), Flags(Flags),
          LastInserter(SDAG.getFlagInserter()) {
      SDAG.setFlagInserter(this);
    }
    FlagInserter(SelectionDAG &SDAG, SDNode *N)
        : FlagInserter(SDAG, N->getFlags()) {}
 
    FlagInserter(const FlagInserter &) = delete;
    FlagInserter &operator=(const FlagInserter &) = delete;
    ~FlagInserter() { DAG.setFlagInserter(LastInserter); }
 
    SDNodeFlags getFlags() const { return Flags; }
  };
 
  /// When true, additional steps are taken to
  /// ensure that getConstant() and similar functions return DAG nodes that
  /// have legal types. This is important after type legalization since
  /// any illegally typed nodes generated after this point will not experience
  /// type legalization.
  bool NewNodesMustHaveLegalTypes = false;
 
private:
  /// DAGUpdateListener is a friend so it can manipulate the listener stack.
  friend struct DAGUpdateListener;
 
  /// Linked list of registered DAGUpdateListener instances.
  /// This stack is maintained by DAGUpdateListener RAII.
  DAGUpdateListener *UpdateListeners = nullptr;
 
  /// Implementation of setSubgraphColor.
  /// Return whether we had to truncate the search.
  bool setSubgraphColorHelper(SDNode *N, const char *Color,
                              DenseSet<SDNode *> &visited,
                              int level, bool &printed);
 
  template <typename SDNodeT, typename... ArgTypes>
  SDNodeT *newSDNode(ArgTypes &&... Args) {
    return new (NodeAllocator.template Allocate<SDNodeT>())
        SDNodeT(std::forward<ArgTypes>(Args)...);
  }
 
  /// Build a synthetic SDNodeT with the given args and extract its subclass
  /// data as an integer (e.g. for use in a folding set).
  ///
  /// The args to this function are the same as the args to SDNodeT's
  /// constructor, except the second arg (assumed to be a const DebugLoc&) is
  /// omitted.
  template <typename SDNodeT, typename... ArgTypes>
  static uint16_t getSyntheticNodeSubclassData(unsigned IROrder,
                                               ArgTypes &&... Args) {
    // The compiler can reduce this expression to a constant iff we pass an
    // empty DebugLoc.  Thankfully, the debug location doesn't have any bearing
    // on the subclass data.
    return SDNodeT(IROrder, DebugLoc(), std::forward<ArgTypes>(Args)...)
        .getRawSubclassData();
  }
 
  template <typename SDNodeTy>
  static uint16_t getSyntheticNodeSubclassData(unsigned Opc, unsigned Order,
                                               SDVTList VTs, EVT MemoryVT,
                                               MachineMemOperand *MMO) {
    return SDNodeTy(Opc, Order, DebugLoc(), VTs, MemoryVT, MMO)
        .getRawSubclassData();
  }
 
  template <typename SDNodeTy>
  static uint16_t getSyntheticNodeSubclassData(
      unsigned Opc, unsigned Order, SDVTList VTs, EVT MemoryVT,
      PointerUnion<MachineMemOperand *, MachineMemOperand **> MemRefs) {
    return SDNodeTy(Opc, Order, DebugLoc(), VTs, MemoryVT, MemRefs)
        .getRawSubclassData();
  }
 
  void createOperands(SDNode *Node, ArrayRef<SDValue> Vals);
 
  void removeOperands(SDNode *Node) {
    if (!Node->OperandList)
      return;
    OperandRecycler.deallocate(
        ArrayRecycler<SDUse>::Capacity::get(Node->NumOperands),
        Node->OperandList);
    Node->NumOperands = 0;
    Node->OperandList = nullptr;
  }
  void CreateTopologicalOrder(std::vector<SDNode*>& Order);
 
public:
  // Maximum depth for recursive analysis such as computeKnownBits, etc.
  static constexpr unsigned MaxRecursionDepth = 6;
 
  // Returns the maximum steps for SDNode->hasPredecessor() like searches.
  LLVM_ABI static unsigned getHasPredecessorMaxSteps();
 
  LLVM_ABI explicit SelectionDAG(const TargetMachine &TM, CodeGenOptLevel);
  SelectionDAG(const SelectionDAG &) = delete;
  SelectionDAG &operator=(const SelectionDAG &) = delete;
  LLVM_ABI ~SelectionDAG();
 
  /// Prepare this SelectionDAG to process code in the given MachineFunction.
  LLVM_ABI void init(MachineFunction &NewMF,
                     const TargetLibraryInfo *LibraryInfo,
                     const LibcallLoweringInfo *LibcallsInfo,
                     UniformityInfo *UA, ProfileSummaryInfo *PSIin,
                     BlockFrequencyInfo *BFIin,
                     FunctionVarLocs const *FnVarLocs);
 
  void init(MachineFunction &NewMF, MachineFunctionAnalysisManager &AM,
            const TargetLibraryInfo *LibraryInfo,
            const LibcallLoweringInfo *LibcallsInfo, UniformityInfo *UA,
            ProfileSummaryInfo *PSIin, BlockFrequencyInfo *BFIin,
            FunctionVarLocs const *FnVarLocs) {
    init(NewMF, LibraryInfo, LibcallsInfo, UA, PSIin, BFIin, FnVarLocs);
    MFAM = &AM;
  }
 
  void setFunctionLoweringInfo(FunctionLoweringInfo * FuncInfo) {
    FLI = FuncInfo;
  }
 
  /// Clear state and free memory necessary to make this
  /// SelectionDAG ready to process a new block.
  LLVM_ABI void clear();
 
  MachineFunction &getMachineFunction() const { return *MF; }
  MachineFunctionAnalysisManager *getMFAM() { return MFAM; }
 
  bool hasSwiftErrorArg() const;
 
  CodeGenOptLevel getOptLevel() const { return OptLevel; }
  const DataLayout &getDataLayout() const { return MF->getDataLayout(); }
  const TargetMachine &getTarget() const { return TM; }
  const TargetSubtargetInfo &getSubtarget() const { return MF->getSubtarget(); }
  template <typename STC> const STC &getSubtarget() const {
    return MF->getSubtarget<STC>();
  }
  const TargetLowering &getTargetLoweringInfo() const { return *TLI; }
  const TargetLibraryInfo &getLibInfo() const { return *LibInfo; }
 
  const LibcallLoweringInfo &getLibcalls() const { return *Libcalls; }
 
  const SelectionDAGTargetInfo &getSelectionDAGInfo() const { return *TSI; }
  const UniformityInfo *getUniformityInfo() const { return UA; }
  /// Returns the result of the AssignmentTrackingAnalysis pass if it's
  /// available, otherwise return nullptr.
  const FunctionVarLocs *getFunctionVarLocs() const { return FnVarLocs; }
  LLVMContext *getContext() const { return Context; }
  ProfileSummaryInfo *getPSI() const { return PSI; }
  BlockFrequencyInfo *getBFI() const { return BFI; }
 
  FlagInserter *getFlagInserter() { return Inserter; }
  void setFlagInserter(FlagInserter *FI) { Inserter = FI; }
 
  /// Just dump dot graph to a user-provided path and title.
  /// This doesn't open the dot viewer program and
  /// helps visualization when outside debugging session.
  /// FileName expects absolute path. If provided
  /// without any path separators then the file
  /// will be created in the current directory.
  /// Error will be emitted if the path is insane.
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
  LLVM_DUMP_METHOD void dumpDotGraph(const Twine &FileName, const Twine &Title);
#endif
 
  /// Pop up a GraphViz/gv window with the DAG rendered using 'dot'.
  LLVM_ABI void viewGraph(const std::string &Title);
  LLVM_ABI void viewGraph();
 
#if LLVM_ENABLE_ABI_BREAKING_CHECKS
  std::map<const SDNode *, std::string> NodeGraphAttrs;
#endif
 
  /// Clear all previously defined node graph attributes.
  /// Intended to be used from a debugging tool (eg. gdb).
  LLVM_ABI void clearGraphAttrs();
 
  /// Set graph attributes for a node. (eg. "color=red".)
  LLVM_ABI void setGraphAttrs(const SDNode *N, const char *Attrs);
 
  /// Get graph attributes for a node. (eg. "color=red".)
  /// Used from getNodeAttributes.
  LLVM_ABI std::string getGraphAttrs(const SDNode *N) const;
 
  /// Convenience for setting node color attribute.
  LLVM_ABI void setGraphColor(const SDNode *N, const char *Color);
 
  /// Convenience for setting subgraph color attribute.
  LLVM_ABI void setSubgraphColor(SDNode *N, const char *Color);
 
  using allnodes_const_iterator = ilist<SDNode>::const_iterator;
 
  allnodes_const_iterator allnodes_begin() const { return AllNodes.begin(); }
  allnodes_const_iterator allnodes_end() const { return AllNodes.end(); }
 
  using allnodes_iterator = ilist<SDNode>::iterator;
 
  allnodes_iterator allnodes_begin() { return AllNodes.begin(); }
  allnodes_iterator allnodes_end() { return AllNodes.end(); }
 
  ilist<SDNode>::size_type allnodes_size() const {
    return AllNodes.size();
  }
 
  iterator_range<allnodes_iterator> allnodes() {
    return make_range(allnodes_begin(), allnodes_end());
  }
  iterator_range<allnodes_const_iterator> allnodes() const {
    return make_range(allnodes_begin(), allnodes_end());
  }
 
  /// Return the root tag of the SelectionDAG.
  const SDValue &getRoot() const { return Root; }
 
  /// Return the token chain corresponding to the entry of the function.
  SDValue getEntryNode() const {
    return SDValue(const_cast<SDNode *>(&EntryNode), 0);
  }
 
  /// Set the current root tag of the SelectionDAG.
  ///
  const SDValue &setRoot(SDValue N) {
    assert((!N.getNode() || N.getValueType() == MVT::Other) &&
           "DAG root value is not a chain!");
    if (N.getNode())
      checkForCycles(N.getNode(), this);
    Root = N;
    if (N.getNode())
      checkForCycles(this);
    return Root;
  }
 
#if !defined(NDEBUG) && LLVM_ENABLE_ABI_BREAKING_CHECKS
  void VerifyDAGDivergence();
#endif
 
  /// This iterates over the nodes in the SelectionDAG, folding
  /// certain types of nodes together, or eliminating superfluous nodes.  The
  /// Level argument controls whether Combine is allowed to produce nodes and
  /// types that are illegal on the target.
  LLVM_ABI void Combine(CombineLevel Level, BatchAAResults *BatchAA,
                        CodeGenOptLevel OptLevel);
 
  /// This transforms the SelectionDAG into a SelectionDAG that
  /// only uses types natively supported by the target.
  /// Returns "true" if it made any changes.
  ///
  /// Note that this is an involved process that may invalidate pointers into
  /// the graph.
  LLVM_ABI bool LegalizeTypes();
 
  /// This transforms the SelectionDAG into a SelectionDAG that is
  /// compatible with the target instruction selector, as indicated by the
  /// TargetLowering object.
  ///
  /// Note that this is an involved process that may invalidate pointers into
  /// the graph.
  LLVM_ABI void Legalize();
 
  /// Transforms a SelectionDAG node and any operands to it into a node
  /// that is compatible with the target instruction selector, as indicated by
  /// the TargetLowering object.
  ///
  /// \returns true if \c N is a valid, legal node after calling this.
  ///
  /// This essentially runs a single recursive walk of the \c Legalize process
  /// over the given node (and its operands). This can be used to incrementally
  /// legalize the DAG. All of the nodes which are directly replaced,
  /// potentially including N, are added to the output parameter \c
  /// UpdatedNodes so that the delta to the DAG can be understood by the
  /// caller.
  ///
  /// When this returns false, N has been legalized in a way that make the
  /// pointer passed in no longer valid. It may have even been deleted from the
  /// DAG, and so it shouldn't be used further. When this returns true, the
  /// N passed in is a legal node, and can be immediately processed as such.
  /// This may still have done some work on the DAG, and will still populate
  /// UpdatedNodes with any new nodes replacing those originally in the DAG.
  LLVM_ABI bool LegalizeOp(SDNode *N,
                           SmallSetVector<SDNode *, 16> &UpdatedNodes);
 
  /// This transforms the SelectionDAG into a SelectionDAG
  /// that only uses vector math operations supported by the target.  This is
  /// necessary as a separate step from Legalize because unrolling a vector
  /// operation can introduce illegal types, which requires running
  /// LegalizeTypes again.
  ///
  /// This returns true if it made any changes; in that case, LegalizeTypes
  /// is called again before Legalize.
  ///
  /// Note that this is an involved process that may invalidate pointers into
  /// the graph.
  LLVM_ABI bool LegalizeVectors();
 
  /// This method deletes all unreachable nodes in the SelectionDAG.
  LLVM_ABI void RemoveDeadNodes();
 
  /// Remove the specified node from the system.  This node must
  /// have no referrers.
  LLVM_ABI void DeleteNode(SDNode *N);
 
  /// Return an SDVTList that represents the list of values specified.
  LLVM_ABI SDVTList getVTList(EVT VT);
  LLVM_ABI SDVTList getVTList(EVT VT1, EVT VT2);
  LLVM_ABI SDVTList getVTList(EVT VT1, EVT VT2, EVT VT3);
  LLVM_ABI SDVTList getVTList(EVT VT1, EVT VT2, EVT VT3, EVT VT4);
  LLVM_ABI SDVTList getVTList(ArrayRef<EVT> VTs);
 
  //===--------------------------------------------------------------------===//
  // Node creation methods.
 
  /// Create a ConstantSDNode wrapping a constant value.
  /// If VT is a vector type, the constant is splatted into a BUILD_VECTOR.
  ///
  /// If only legal types can be produced, this does the necessary
  /// transformations (e.g., if the vector element type is illegal).
  /// @{
  LLVM_ABI SDValue getConstant(uint64_t Val, const SDLoc &DL, EVT VT,
                               bool isTarget = false, bool isOpaque = false);
  LLVM_ABI SDValue getConstant(const APInt &Val, const SDLoc &DL, EVT VT,
                               bool isTarget = false, bool isOpaque = false);
 
  LLVM_ABI SDValue getSignedConstant(int64_t Val, const SDLoc &DL, EVT VT,
                                     bool isTarget = false,
                                     bool isOpaque = false);
 
  LLVM_ABI SDValue getAllOnesConstant(const SDLoc &DL, EVT VT,
                                      bool IsTarget = false,
                                      bool IsOpaque = false);
 
  LLVM_ABI SDValue getConstant(const ConstantInt &Val, const SDLoc &DL, EVT VT,
                               bool isTarget = false, bool isOpaque = false);
  LLVM_ABI SDValue getIntPtrConstant(uint64_t Val, const SDLoc &DL,
                                     bool isTarget = false);
  LLVM_ABI SDValue getShiftAmountConstant(uint64_t Val, EVT VT,
                                          const SDLoc &DL);
  LLVM_ABI SDValue getShiftAmountConstant(const APInt &Val, EVT VT,
                                          const SDLoc &DL);
  LLVM_ABI SDValue getVectorIdxConstant(uint64_t Val, const SDLoc &DL,
                                        bool isTarget = false);
 
  SDValue getTargetConstant(uint64_t Val, const SDLoc &DL, EVT VT,
                            bool isOpaque = false) {
    return getConstant(Val, DL, VT, true, isOpaque);
  }
  SDValue getTargetConstant(const APInt &Val, const SDLoc &DL, EVT VT,
                            bool isOpaque = false) {
    return getConstant(Val, DL, VT, true, isOpaque);
  }
  SDValue getTargetConstant(const ConstantInt &Val, const SDLoc &DL, EVT VT,
                            bool isOpaque = false) {
    return getConstant(Val, DL, VT, true, isOpaque);
  }
  SDValue getSignedTargetConstant(int64_t Val, const SDLoc &DL, EVT VT,
                                  bool isOpaque = false) {
    return getSignedConstant(Val, DL, VT, true, isOpaque);
  }
 
  /// Create a true or false constant of type \p VT using the target's
  /// BooleanContent for type \p OpVT.
  LLVM_ABI SDValue getBoolConstant(bool V, const SDLoc &DL, EVT VT, EVT OpVT);
  /// @}
 
  /// Create a ConstantFPSDNode wrapping a constant value.
  /// If VT is a vector type, the constant is splatted into a BUILD_VECTOR.
  ///
  /// If only legal types can be produced, this does the necessary
  /// transformations (e.g., if the vector element type is illegal).
  /// The forms that take a double should only be used for simple constants
  /// that can be exactly represented in VT.  No checks are made.
  /// @{
  LLVM_ABI SDValue getConstantFP(double Val, const SDLoc &DL, EVT VT,
                                 bool isTarget = false);
  LLVM_ABI SDValue getConstantFP(const APFloat &Val, const SDLoc &DL, EVT VT,
                                 bool isTarget = false);
  LLVM_ABI SDValue getConstantFP(const ConstantFP &V, const SDLoc &DL, EVT VT,
                                 bool isTarget = false);
  SDValue getTargetConstantFP(double Val, const SDLoc &DL, EVT VT) {
    return getConstantFP(Val, DL, VT, true);
  }
  SDValue getTargetConstantFP(const APFloat &Val, const SDLoc &DL, EVT VT) {
    return getConstantFP(Val, DL, VT, true);
  }
  SDValue getTargetConstantFP(const ConstantFP &Val, const SDLoc &DL, EVT VT) {
    return getConstantFP(Val, DL, VT, true);
  }
  /// @}
 
  LLVM_ABI SDValue getGlobalAddress(const GlobalValue *GV, const SDLoc &DL,
                                    EVT VT, int64_t offset = 0,
                                    bool isTargetGA = false,
                                    unsigned TargetFlags = 0);
  SDValue getTargetGlobalAddress(const GlobalValue *GV, const SDLoc &DL, EVT VT,
                                 int64_t offset = 0, unsigned TargetFlags = 0) {
    return getGlobalAddress(GV, DL, VT, offset, true, TargetFlags);
  }
  LLVM_ABI SDValue getDeactivationSymbol(const GlobalValue *GV);
  LLVM_ABI SDValue getFrameIndex(int FI, EVT VT, bool isTarget = false);
  SDValue getTargetFrameIndex(int FI, EVT VT) {
    return getFrameIndex(FI, VT, true);
  }
  LLVM_ABI SDValue getJumpTable(int JTI, EVT VT, bool isTarget = false,
                                unsigned TargetFlags = 0);
  SDValue getTargetJumpTable(int JTI, EVT VT, unsigned TargetFlags = 0) {
    return getJumpTable(JTI, VT, true, TargetFlags);
  }
  LLVM_ABI SDValue getJumpTableDebugInfo(int JTI, SDValue Chain,
                                         const SDLoc &DL);
  LLVM_ABI SDValue getConstantPool(const Constant *C, EVT VT,
                                   MaybeAlign Align = std::nullopt,
                                   int Offs = 0, bool isT = false,
                                   unsigned TargetFlags = 0);
  SDValue getTargetConstantPool(const Constant *C, EVT VT,
                                MaybeAlign Align = std::nullopt, int Offset = 0,
                                unsigned TargetFlags = 0) {
    return getConstantPool(C, VT, Align, Offset, true, TargetFlags);
  }
  LLVM_ABI SDValue getConstantPool(MachineConstantPoolValue *C, EVT VT,
                                   MaybeAlign Align = std::nullopt,
                                   int Offs = 0, bool isT = false,
                                   unsigned TargetFlags = 0);
  SDValue getTargetConstantPool(MachineConstantPoolValue *C, EVT VT,
                                MaybeAlign Align = std::nullopt, int Offset = 0,
                                unsigned TargetFlags = 0) {
    return getConstantPool(C, VT, Align, Offset, true, TargetFlags);
  }
  // When generating a branch to a BB, we don't in general know enough
  // to provide debug info for the BB at that time, so keep this one around.
  LLVM_ABI SDValue getBasicBlock(MachineBasicBlock *MBB);
  LLVM_ABI SDValue getExternalSymbol(const char *Sym, EVT VT);
  LLVM_ABI SDValue getExternalSymbol(RTLIB::LibcallImpl LCImpl, EVT VT);
  LLVM_ABI SDValue getTargetExternalSymbol(const char *Sym, EVT VT,
                                           unsigned TargetFlags = 0);
  LLVM_ABI SDValue getTargetExternalSymbol(RTLIB::LibcallImpl LCImpl, EVT VT,
                                           unsigned TargetFlags = 0);
 
  LLVM_ABI SDValue getMCSymbol(MCSymbol *Sym, EVT VT);
 
  LLVM_ABI SDValue getValueType(EVT);
  LLVM_ABI SDValue getRegister(Register Reg, EVT VT);
  LLVM_ABI SDValue getRegisterMask(const uint32_t *RegMask);
  LLVM_ABI SDValue getEHLabel(const SDLoc &dl, SDValue Root, MCSymbol *Label);
  LLVM_ABI SDValue getLabelNode(unsigned Opcode, const SDLoc &dl, SDValue Root,
                                MCSymbol *Label);
  LLVM_ABI SDValue getBlockAddress(const BlockAddress *BA, EVT VT,
                                   int64_t Offset = 0, bool isTarget = false,
                                   unsigned TargetFlags = 0);
  SDValue getTargetBlockAddress(const BlockAddress *BA, EVT VT,
                                int64_t Offset = 0, unsigned TargetFlags = 0) {
    return getBlockAddress(BA, VT, Offset, true, TargetFlags);
  }
 
  SDValue getCopyToReg(SDValue Chain, const SDLoc &dl, Register Reg,
                       SDValue N) {
    return getNode(ISD::CopyToReg, dl, MVT::Other, Chain,
                   getRegister(Reg, N.getValueType()), N);
  }
 
  // This version of the getCopyToReg method takes an extra operand, which
  // indicates that there is potentially an incoming glue value (if Glue is not
  // null) and that there should be a glue result.
  SDValue getCopyToReg(SDValue Chain, const SDLoc &dl, Register Reg, SDValue N,
                       SDValue Glue) {
    SDVTList VTs = getVTList(MVT::Other, MVT::Glue);
    SDValue Ops[] = { Chain, getRegister(Reg, N.getValueType()), N, Glue };
    return getNode(ISD::CopyToReg, dl, VTs,
                   ArrayRef(Ops, Glue.getNode() ? 4 : 3));
  }
 
  // Similar to last getCopyToReg() except parameter Reg is a SDValue
  SDValue getCopyToReg(SDValue Chain, const SDLoc &dl, SDValue Reg, SDValue N,
                       SDValue Glue) {
    SDVTList VTs = getVTList(MVT::Other, MVT::Glue);
    SDValue Ops[] = { Chain, Reg, N, Glue };
    return getNode(ISD::CopyToReg, dl, VTs,
                   ArrayRef(Ops, Glue.getNode() ? 4 : 3));
  }
 
  SDValue getCopyFromReg(SDValue Chain, const SDLoc &dl, Register Reg, EVT VT) {
    SDVTList VTs = getVTList(VT, MVT::Other);
    SDValue Ops[] = { Chain, getRegister(Reg, VT) };
    return getNode(ISD::CopyFromReg, dl, VTs, Ops);
  }
 
  // This version of the getCopyFromReg method takes an extra operand, which
  // indicates that there is potentially an incoming glue value (if Glue is not
  // null) and that there should be a glue result.
  SDValue getCopyFromReg(SDValue Chain, const SDLoc &dl, Register Reg, EVT VT,
                         SDValue Glue) {
    SDVTList VTs = getVTList(VT, MVT::Other, MVT::Glue);
    SDValue Ops[] = { Chain, getRegister(Reg, VT), Glue };
    return getNode(ISD::CopyFromReg, dl, VTs,
                   ArrayRef(Ops, Glue.getNode() ? 3 : 2));
  }
 
  LLVM_ABI SDValue getCondCode(ISD::CondCode Cond);
 
  /// Return an ISD::VECTOR_SHUFFLE node. The number of elements in VT,
  /// which must be a vector type, must match the number of mask elements
  /// NumElts. An integer mask element equal to -1 is treated as undefined.
  LLVM_ABI SDValue getVectorShuffle(EVT VT, const SDLoc &dl, SDValue N1,
                                    SDValue N2, ArrayRef<int> Mask);
 
  /// Return an ISD::BUILD_VECTOR node. The number of elements in VT,
  /// which must be a vector type, must match the number of operands in Ops.
  /// The operands must have the same type as (or, for integers, a type wider
  /// than) VT's element type.
  SDValue getBuildVector(EVT VT, const SDLoc &DL, ArrayRef<SDValue> Ops) {
    // VerifySDNode (via InsertNode) checks BUILD_VECTOR later.
    return getNode(ISD::BUILD_VECTOR, DL, VT, Ops);
  }
 
  /// Return an ISD::BUILD_VECTOR node. The number of elements in VT,
  /// which must be a vector type, must match the number of operands in Ops.
  /// The operands must have the same type as (or, for integers, a type wider
  /// than) VT's element type.
  SDValue getBuildVector(EVT VT, const SDLoc &DL, ArrayRef<SDUse> Ops) {
    // VerifySDNode (via InsertNode) checks BUILD_VECTOR later.
    return getNode(ISD::BUILD_VECTOR, DL, VT, Ops);
  }
 
  /// Return a splat ISD::BUILD_VECTOR node, consisting of Op splatted to all
  /// elements. VT must be a vector type. Op's type must be the same as (or,
  /// for integers, a type wider than) VT's element type.
  SDValue getSplatBuildVector(EVT VT, const SDLoc &DL, SDValue Op) {
    // VerifySDNode (via InsertNode) checks BUILD_VECTOR later.
    if (Op.isUndef()) {
      assert((VT.getVectorElementType() == Op.getValueType() ||
              (VT.isInteger() &&
               VT.getVectorElementType().bitsLE(Op.getValueType()))) &&
             "A splatted value must have a width equal or (for integers) "
             "greater than the vector element type!");
      return getNode(ISD::UNDEF, SDLoc(), VT);
    }
 
    SmallVector<SDValue, 16> Ops(VT.getVectorNumElements(), Op);
    return getNode(ISD::BUILD_VECTOR, DL, VT, Ops);
  }
 
  // Return a splat ISD::SPLAT_VECTOR node, consisting of Op splatted to all
  // elements.
  SDValue getSplatVector(EVT VT, const SDLoc &DL, SDValue Op) {
    if (Op.isUndef()) {
      assert((VT.getVectorElementType() == Op.getValueType() ||
              (VT.isInteger() &&
               VT.getVectorElementType().bitsLE(Op.getValueType()))) &&
             "A splatted value must have a width equal or (for integers) "
             "greater than the vector element type!");
      return getNode(ISD::UNDEF, SDLoc(), VT);
    }
    return getNode(ISD::SPLAT_VECTOR, DL, VT, Op);
  }
 
  /// Returns a node representing a splat of one value into all lanes
  /// of the provided vector type.  This is a utility which returns
  /// either a BUILD_VECTOR or SPLAT_VECTOR depending on the
  /// scalability of the desired vector type.
  SDValue getSplat(EVT VT, const SDLoc &DL, SDValue Op) {
    assert(VT.isVector() && "Can't splat to non-vector type");
    return VT.isScalableVector() ?
      getSplatVector(VT, DL, Op) : getSplatBuildVector(VT, DL, Op);
  }
 
  /// Returns a vector of type ResVT whose elements contain the linear sequence
  ///   <0, Step, Step * 2, Step * 3, ...>
  LLVM_ABI SDValue getStepVector(const SDLoc &DL, EVT ResVT,
                                 const APInt &StepVal);
 
  /// Returns a vector of type ResVT whose elements contain the linear sequence
  ///   <0, 1, 2, 3, ...>
  LLVM_ABI SDValue getStepVector(const SDLoc &DL, EVT ResVT);
 
  /// Returns an ISD::VECTOR_SHUFFLE node semantically equivalent to
  /// the shuffle node in input but with swapped operands.
  ///
  /// Example: shuffle A, B, <0,5,2,7> -> shuffle B, A, <4,1,6,3>
  LLVM_ABI SDValue getCommutedVectorShuffle(const ShuffleVectorSDNode &SV);
 
  /// Extract element at \p Idx from \p Vec.  See EXTRACT_VECTOR_ELT
  /// description for result type handling.
  SDValue getExtractVectorElt(const SDLoc &DL, EVT VT, SDValue Vec,
                              unsigned Idx) {
    return getNode(ISD::EXTRACT_VECTOR_ELT, DL, VT, Vec,
                   getVectorIdxConstant(Idx, DL));
  }
 
  /// Insert \p Elt into \p Vec at offset \p Idx.  See INSERT_VECTOR_ELT
  /// description for element type handling.
  SDValue getInsertVectorElt(const SDLoc &DL, SDValue Vec, SDValue Elt,
                             unsigned Idx) {
    return getNode(ISD::INSERT_VECTOR_ELT, DL, Vec.getValueType(), Vec, Elt,
                   getVectorIdxConstant(Idx, DL));
  }
 
  /// Insert \p SubVec at the \p Idx element of \p Vec.
  SDValue getInsertSubvector(const SDLoc &DL, SDValue Vec, SDValue SubVec,
                             unsigned Idx) {
    return getNode(ISD::INSERT_SUBVECTOR, DL, Vec.getValueType(), Vec, SubVec,
                   getVectorIdxConstant(Idx, DL));
  }
 
  /// Return the \p VT typed sub-vector of \p Vec at \p Idx
  SDValue getExtractSubvector(const SDLoc &DL, EVT VT, SDValue Vec,
                              unsigned Idx) {
    return getNode(ISD::EXTRACT_SUBVECTOR, DL, VT, Vec,
                   getVectorIdxConstant(Idx, DL));
  }
 
  /// Convert Op, which must be of float type, to the
  /// float type VT, by either extending or rounding (by truncation).
  LLVM_ABI SDValue getFPExtendOrRound(SDValue Op, const SDLoc &DL, EVT VT);
 
  /// Convert Op, which must be a STRICT operation of float type, to the
  /// float type VT, by either extending or rounding (by truncation).
  LLVM_ABI std::pair<SDValue, SDValue>
  getStrictFPExtendOrRound(SDValue Op, SDValue Chain, const SDLoc &DL, EVT VT);
 
  /// Convert *_EXTEND_VECTOR_INREG to *_EXTEND opcode.
  static unsigned getOpcode_EXTEND(unsigned Opcode) {
    switch (Opcode) {
    case ISD::ANY_EXTEND:
    case ISD::ANY_EXTEND_VECTOR_INREG:
      return ISD::ANY_EXTEND;
    case ISD::ZERO_EXTEND:
    case ISD::ZERO_EXTEND_VECTOR_INREG:
      return ISD::ZERO_EXTEND;
    case ISD::SIGN_EXTEND:
    case ISD::SIGN_EXTEND_VECTOR_INREG:
      return ISD::SIGN_EXTEND;
    }
    llvm_unreachable("Unknown opcode");
  }
 
  /// Convert *_EXTEND to *_EXTEND_VECTOR_INREG opcode.
  static unsigned getOpcode_EXTEND_VECTOR_INREG(unsigned Opcode) {
    switch (Opcode) {
    case ISD::ANY_EXTEND:
    case ISD::ANY_EXTEND_VECTOR_INREG:
      return ISD::ANY_EXTEND_VECTOR_INREG;
    case ISD::ZERO_EXTEND:
    case ISD::ZERO_EXTEND_VECTOR_INREG:
      return ISD::ZERO_EXTEND_VECTOR_INREG;
    case ISD::SIGN_EXTEND:
    case ISD::SIGN_EXTEND_VECTOR_INREG:
      return ISD::SIGN_EXTEND_VECTOR_INREG;
    }
    llvm_unreachable("Unknown opcode");
  }
 
  /// Convert Op, which must be of integer type, to the
  /// integer type VT, by either any-extending or truncating it.
  LLVM_ABI SDValue getAnyExtOrTrunc(SDValue Op, const SDLoc &DL, EVT VT);
 
  /// Convert Op, which must be of integer type, to the
  /// integer type VT, by either sign-extending or truncating it.
  LLVM_ABI SDValue getSExtOrTrunc(SDValue Op, const SDLoc &DL, EVT VT);
 
  /// Convert Op, which must be of integer type, to the
  /// integer type VT, by either zero-extending or truncating it.
  LLVM_ABI SDValue getZExtOrTrunc(SDValue Op, const SDLoc &DL, EVT VT);
 
  /// Convert Op, which must be of integer type, to the
  /// integer type VT, by either any/sign/zero-extending (depending on IsAny /
  /// IsSigned) or truncating it.
  SDValue getExtOrTrunc(SDValue Op, const SDLoc &DL,
                        EVT VT, unsigned Opcode) {
    switch(Opcode) {
      case ISD::ANY_EXTEND:
        return getAnyExtOrTrunc(Op, DL, VT);
      case ISD::ZERO_EXTEND:
        return getZExtOrTrunc(Op, DL, VT);
      case ISD::SIGN_EXTEND:
        return getSExtOrTrunc(Op, DL, VT);
    }
    llvm_unreachable("Unsupported opcode");
  }
 
  /// Convert Op, which must be of integer type, to the
  /// integer type VT, by either sign/zero-extending (depending on IsSigned) or
  /// truncating it.
  SDValue getExtOrTrunc(bool IsSigned, SDValue Op, const SDLoc &DL, EVT VT) {
    return IsSigned ? getSExtOrTrunc(Op, DL, VT) : getZExtOrTrunc(Op, DL, VT);
  }
 
  /// Convert Op, which must be of integer type, to the
  /// integer type VT, by first bitcasting (from potential vector) to
  /// corresponding scalar type then either any-extending or truncating it.
  LLVM_ABI SDValue getBitcastedAnyExtOrTrunc(SDValue Op, const SDLoc &DL,
                                             EVT VT);
 
  /// Return the expression required to zero extend the Op
  /// value assuming it was the smaller SrcTy value.
  LLVM_ABI SDValue getZeroExtendInReg(SDValue Op, const SDLoc &DL, EVT VT);
 
  /// Convert Op, which must be of integer type, to the integer type VT, by
  /// either truncating it or performing either zero or sign extension as
  /// appropriate extension for the pointer's semantics.
  LLVM_ABI SDValue getPtrExtOrTrunc(SDValue Op, const SDLoc &DL, EVT VT);
 
  /// Return the expression required to extend the Op as a pointer value
  /// assuming it was the smaller SrcTy value. This may be either a zero extend
  /// or a sign extend.
  LLVM_ABI SDValue getPtrExtendInReg(SDValue Op, const SDLoc &DL, EVT VT);
 
  /// Convert Op, which must be of integer type, to the integer type VT,
  /// by using an extension appropriate for the target's
  /// BooleanContent for type OpVT or truncating it.
  LLVM_ABI SDValue getBoolExtOrTrunc(SDValue Op, const SDLoc &SL, EVT VT,
                                     EVT OpVT);
 
  /// Create negative operation as (SUB 0, Val).
  LLVM_ABI SDValue getNegative(SDValue Val, const SDLoc &DL, EVT VT);
 
  /// Create a bitwise NOT operation as (XOR Val, -1).
  LLVM_ABI SDValue getNOT(const SDLoc &DL, SDValue Val, EVT VT);
 
  /// Create a logical NOT operation as (XOR Val, BooleanOne).
  LLVM_ABI SDValue getLogicalNOT(const SDLoc &DL, SDValue Val, EVT VT);
 
  /// Returns sum of the base pointer and offset.
  /// Unlike getObjectPtrOffset this does not set NoUnsignedWrap and InBounds by
  /// default.
  LLVM_ABI SDValue
  getMemBasePlusOffset(SDValue Base, TypeSize Offset, const SDLoc &DL,
                       const SDNodeFlags Flags = SDNodeFlags());
  LLVM_ABI SDValue
  getMemBasePlusOffset(SDValue Base, SDValue Offset, const SDLoc &DL,
                       const SDNodeFlags Flags = SDNodeFlags());
 
  /// Create an add instruction with appropriate flags when used for
  /// addressing some offset of an object. i.e. if a load is split into multiple
  /// components, create an add nuw (or ptradd nuw inbounds) from the base
  /// pointer to the offset.
  SDValue getObjectPtrOffset(const SDLoc &SL, SDValue Ptr, TypeSize Offset) {
    return getMemBasePlusOffset(
        Ptr, Offset, SL, SDNodeFlags::NoUnsignedWrap | SDNodeFlags::InBounds);
  }
 
  SDValue getObjectPtrOffset(const SDLoc &SL, SDValue Ptr, SDValue Offset) {
    // The object itself can't wrap around the address space, so it shouldn't be
    // possible for the adds of the offsets to the split parts to overflow.
    return getMemBasePlusOffset(
        Ptr, Offset, SL, SDNodeFlags::NoUnsignedWrap | SDNodeFlags::InBounds);
  }
 
  /// Return a new CALLSEQ_START node, that starts new call frame, in which
  /// InSize bytes are set up inside CALLSEQ_START..CALLSEQ_END sequence and
  /// OutSize specifies part of the frame set up prior to the sequence.
  SDValue getCALLSEQ_START(SDValue Chain, uint64_t InSize, uint64_t OutSize,
                           const SDLoc &DL) {
    SDVTList VTs = getVTList(MVT::Other, MVT::Glue);
    SDValue Ops[] = { Chain,
                      getIntPtrConstant(InSize, DL, true),
                      getIntPtrConstant(OutSize, DL, true) };
    return getNode(ISD::CALLSEQ_START, DL, VTs, Ops);
  }
 
  /// Return a new CALLSEQ_END node, which always must have a
  /// glue result (to ensure it's not CSE'd).
  /// CALLSEQ_END does not have a useful SDLoc.
  SDValue getCALLSEQ_END(SDValue Chain, SDValue Op1, SDValue Op2,
                         SDValue InGlue, const SDLoc &DL) {
    SDVTList NodeTys = getVTList(MVT::Other, MVT::Glue);
    SmallVector<SDValue, 4> Ops;
    Ops.push_back(Chain);
    Ops.push_back(Op1);
    Ops.push_back(Op2);
    if (InGlue.getNode())
      Ops.push_back(InGlue);
    return getNode(ISD::CALLSEQ_END, DL, NodeTys, Ops);
  }
 
  SDValue getCALLSEQ_END(SDValue Chain, uint64_t Size1, uint64_t Size2,
                         SDValue Glue, const SDLoc &DL) {
    return getCALLSEQ_END(
        Chain, getIntPtrConstant(Size1, DL, /*isTarget=*/true),
        getIntPtrConstant(Size2, DL, /*isTarget=*/true), Glue, DL);
  }
 
  /// Return true if the result of this operation is always undefined.
  LLVM_ABI bool isUndef(unsigned Opcode, ArrayRef<SDValue> Ops);
 
  /// Return an UNDEF node. UNDEF does not have a useful SDLoc.
  SDValue getUNDEF(EVT VT) {
    return getNode(ISD::UNDEF, SDLoc(), VT);
  }
 
  /// Return a POISON node. POISON does not have a useful SDLoc.
  SDValue getPOISON(EVT VT) { return getNode(ISD::POISON, SDLoc(), VT); }
 
  /// Return a node that represents the runtime scaling 'MulImm * RuntimeVL'.
  LLVM_ABI SDValue getVScale(const SDLoc &DL, EVT VT, APInt MulImm);
 
  LLVM_ABI SDValue getElementCount(const SDLoc &DL, EVT VT, ElementCount EC);
 
  LLVM_ABI SDValue getTypeSize(const SDLoc &DL, EVT VT, TypeSize TS);
 
  /// Return a vector with the first 'Len' lanes set to true and remaining lanes
  /// set to false. The mask's ValueType is the same as when comparing vectors
  /// of type VT.
  LLVM_ABI SDValue getMaskFromElementCount(const SDLoc &DL, EVT VT,
                                           ElementCount Len);
 
  /// Return a GLOBAL_OFFSET_TABLE node. This does not have a useful SDLoc.
  SDValue getGLOBAL_OFFSET_TABLE(EVT VT) {
    return getNode(ISD::GLOBAL_OFFSET_TABLE, SDLoc(), VT);
  }
 
  /// Gets or creates the specified node.
  ///
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
                           ArrayRef<SDUse> Ops);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
                           ArrayRef<SDValue> Ops, const SDNodeFlags Flags);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL,
                           ArrayRef<EVT> ResultTys, ArrayRef<SDValue> Ops,
                           const SDNodeFlags Flags);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList,
                           ArrayRef<SDValue> Ops, const SDNodeFlags Flags);
 
  // Use flags from current flag inserter.
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
                           ArrayRef<SDValue> Ops);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL,
                           ArrayRef<EVT> ResultTys, ArrayRef<SDValue> Ops);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList,
                           ArrayRef<SDValue> Ops);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
                           SDValue Operand);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                           SDValue N2);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                           SDValue N2, SDValue N3);
 
  // Specialize based on number of operands.
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
                           SDValue Operand, const SDNodeFlags Flags);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                           SDValue N2, const SDNodeFlags Flags);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                           SDValue N2, SDValue N3, const SDNodeFlags Flags);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                           SDValue N2, SDValue N3, SDValue N4);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                           SDValue N2, SDValue N3, SDValue N4,
                           const SDNodeFlags Flags);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                           SDValue N2, SDValue N3, SDValue N4, SDValue N5);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                           SDValue N2, SDValue N3, SDValue N4, SDValue N5,
                           const SDNodeFlags Flags);
 
  // Specialize again based on number of operands for nodes with a VTList
  // rather than a single VT.
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList,
                           SDValue N);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList,
                           SDValue N1, SDValue N2);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList,
                           SDValue N1, SDValue N2, SDValue N3);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList,
                           SDValue N1, SDValue N2, SDValue N3, SDValue N4);
  LLVM_ABI SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList,
                           SDValue N1, SDValue N2, SDValue N3, SDValue N4,
                           SDValue N5);
 
  /// Compute a TokenFactor to force all the incoming stack arguments to be
  /// loaded from the stack. This is used in tail call lowering to protect
  /// stack arguments from being clobbered.
  LLVM_ABI SDValue getStackArgumentTokenFactor(SDValue Chain);
 
  /// Lower a memccpy operation into a target library call and return the
  /// resulting chain and call result as SelectionDAG SDValues.
  LLVM_ABI std::pair<SDValue, SDValue>
  getMemccpy(SDValue Chain, const SDLoc &dl, SDValue Dst, SDValue Src,
             SDValue C, SDValue Size, const CallInst *CI);
 
  /// Lower a memcmp operation into a target library call and return the
  /// resulting chain and call result as SelectionDAG SDValues.
  LLVM_ABI std::pair<SDValue, SDValue> getMemcmp(SDValue Chain, const SDLoc &dl,
                                                 SDValue Dst, SDValue Src,
                                                 SDValue Size,
                                                 const CallInst *CI);
 
  /// Lower a strcmp operation into a target library call and return the
  /// resulting chain and call result as SelectionDAG SDValues.
  LLVM_ABI std::pair<SDValue, SDValue> getStrcmp(SDValue Chain, const SDLoc &dl,
                                                 SDValue S0, SDValue S1,
                                                 const CallInst *CI);
 
  /// Lower a strcpy operation into a target library call and return the
  /// resulting chain and call result as SelectionDAG SDValues.
  LLVM_ABI std::pair<SDValue, SDValue> getStrcpy(SDValue Chain, const SDLoc &dl,
                                                 SDValue Dst, SDValue Src,
                                                 const CallInst *CI);
 
  /// Lower a strlen operation into a target library call and return the
  /// resulting chain and call result as SelectionDAG SDValues.
  LLVM_ABI std::pair<SDValue, SDValue>
  getStrlen(SDValue Chain, const SDLoc &dl, SDValue Src, const CallInst *CI);
 
  /// Lower a strstr operation into a target library call and return the
  /// resulting chain and call result as SelectionDAG SDValues.
  LLVM_ABI std::pair<SDValue, SDValue> getStrstr(SDValue Chain, const SDLoc &dl,
                                                 SDValue S0, SDValue S1,
                                                 const CallInst *CI);
 
  /* \p CI if not null is the memset call being lowered.
   * \p OverrideTailCall is an optional parameter that can be used to override
   * the tail call optimization decision. */
  LLVM_ABI SDValue getMemcpy(
      SDValue Chain, const SDLoc &dl, SDValue Dst, SDValue Src, SDValue Size,
      Align DstAlign, Align SrcAlign, bool isVol, bool AlwaysInline,
      const CallInst *CI, std::optional<bool> OverrideTailCall,
      MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo,
      const AAMDNodes &AAInfo = AAMDNodes(), BatchAAResults *BatchAA = nullptr);
 
  /* \p CI if not null is the memset call being lowered.
   * \p OverrideTailCall is an optional parameter that can be used to override
   * the tail call optimization decision. */
  LLVM_ABI SDValue getMemmove(SDValue Chain, const SDLoc &dl, SDValue Dst,
                              SDValue Src, SDValue Size, Align DstAlign,
                              Align SrcAlign, bool isVol, const CallInst *CI,
                              std::optional<bool> OverrideTailCall,
                              MachinePointerInfo DstPtrInfo,
                              MachinePointerInfo SrcPtrInfo,
                              const AAMDNodes &AAInfo = AAMDNodes(),
                              BatchAAResults *BatchAA = nullptr);
 
  LLVM_ABI SDValue getMemset(SDValue Chain, const SDLoc &dl, SDValue Dst,
                             SDValue Src, SDValue Size, Align Alignment,
                             bool isVol, bool AlwaysInline, const CallInst *CI,
                             MachinePointerInfo DstPtrInfo,
                             const AAMDNodes &AAInfo = AAMDNodes());
 
  LLVM_ABI SDValue getAtomicMemcpy(SDValue Chain, const SDLoc &dl, SDValue Dst,
                                   SDValue Src, SDValue Size, Type *SizeTy,
                                   unsigned ElemSz, bool isTailCall,
                                   MachinePointerInfo DstPtrInfo,
                                   MachinePointerInfo SrcPtrInfo);
 
  LLVM_ABI SDValue getAtomicMemmove(SDValue Chain, const SDLoc &dl, SDValue Dst,
                                    SDValue Src, SDValue Size, Type *SizeTy,
                                    unsigned ElemSz, bool isTailCall,
                                    MachinePointerInfo DstPtrInfo,
                                    MachinePointerInfo SrcPtrInfo);
 
  LLVM_ABI SDValue getAtomicMemset(SDValue Chain, const SDLoc &dl, SDValue Dst,
                                   SDValue Value, SDValue Size, Type *SizeTy,
                                   unsigned ElemSz, bool isTailCall,
                                   MachinePointerInfo DstPtrInfo);
 
  /// Helper function to make it easier to build SetCC's if you just have an
  /// ISD::CondCode instead of an SDValue.
  SDValue getSetCC(const SDLoc &DL, EVT VT, SDValue LHS, SDValue RHS,
                   ISD::CondCode Cond, SDValue Chain = SDValue(),
                   bool IsSignaling = false, SDNodeFlags Flags = {}) {
    assert(LHS.getValueType().isVector() == RHS.getValueType().isVector() &&
           "Vector/scalar operand type mismatch for setcc");
    assert(LHS.getValueType().isVector() == VT.isVector() &&
           "Vector/scalar result type mismatch for setcc");
    assert(Cond != ISD::SETCC_INVALID &&
           "Cannot create a setCC of an invalid node.");
    if (Chain)
      return getNode(IsSignaling ? ISD::STRICT_FSETCCS : ISD::STRICT_FSETCC, DL,
                     {VT, MVT::Other}, {Chain, LHS, RHS, getCondCode(Cond)},
                     Flags);
    return getNode(ISD::SETCC, DL, VT, LHS, RHS, getCondCode(Cond), Flags);
  }
 
  /// Helper function to make it easier to build Select's if you just have
  /// operands and don't want to check for vector.
  SDValue getSelect(const SDLoc &DL, EVT VT, SDValue Cond, SDValue LHS,
                    SDValue RHS, SDNodeFlags Flags = SDNodeFlags()) {
    assert(LHS.getValueType() == VT && RHS.getValueType() == VT &&
           "Cannot use select on differing types");
    auto Opcode = Cond.getValueType().isVector() ? ISD::VSELECT : ISD::SELECT;
    return getNode(Opcode, DL, VT, Cond, LHS, RHS, Flags);
  }
 
  /// Helper function to make it easier to build SelectCC's if you just have an
  /// ISD::CondCode instead of an SDValue.
  SDValue getSelectCC(const SDLoc &DL, SDValue LHS, SDValue RHS, SDValue True,
                      SDValue False, ISD::CondCode Cond,
                      SDNodeFlags Flags = SDNodeFlags()) {
    return getNode(ISD::SELECT_CC, DL, True.getValueType(), LHS, RHS, True,
                   False, getCondCode(Cond), Flags);
  }
 
  /// Try to simplify a select/vselect into 1 of its operands or a constant.
  LLVM_ABI SDValue simplifySelect(SDValue Cond, SDValue TVal, SDValue FVal);
 
  /// Try to simplify a shift into 1 of its operands or a constant.
  LLVM_ABI SDValue simplifyShift(SDValue X, SDValue Y);
 
  /// Try to simplify a floating-point binary operation into 1 of its operands
  /// or a constant.
  LLVM_ABI SDValue simplifyFPBinop(unsigned Opcode, SDValue X, SDValue Y,
                                   SDNodeFlags Flags);
 
  /// VAArg produces a result and token chain, and takes a pointer
  /// and a source value as input.
  LLVM_ABI SDValue getVAArg(EVT VT, const SDLoc &dl, SDValue Chain, SDValue Ptr,
                            SDValue SV, unsigned Align);
 
  /// Gets a node for an atomic cmpxchg op. There are two
  /// valid Opcodes. ISD::ATOMIC_CMO_SWAP produces the value loaded and a
  /// chain result. ISD::ATOMIC_CMP_SWAP_WITH_SUCCESS produces the value loaded,
  /// a success flag (initially i1), and a chain.
  LLVM_ABI SDValue getAtomicCmpSwap(unsigned Opcode, const SDLoc &dl, EVT MemVT,
                                    SDVTList VTs, SDValue Chain, SDValue Ptr,
                                    SDValue Cmp, SDValue Swp,
                                    MachineMemOperand *MMO);
 
  /// Gets a node for an atomic op, produces result (if relevant)
  /// and chain and takes 2 operands.
  LLVM_ABI SDValue getAtomic(unsigned Opcode, const SDLoc &dl, EVT MemVT,
                             SDValue Chain, SDValue Ptr, SDValue Val,
                             MachineMemOperand *MMO);
 
  /// Gets a node for an atomic op, produces result and chain and takes N
  /// operands.
  LLVM_ABI SDValue getAtomic(unsigned Opcode, const SDLoc &dl, EVT MemVT,
                             SDVTList VTList, ArrayRef<SDValue> Ops,
                             MachineMemOperand *MMO,
                             ISD::LoadExtType ExtType = ISD::NON_EXTLOAD);
 
  LLVM_ABI SDValue getAtomicLoad(ISD::LoadExtType ExtType, const SDLoc &dl,
                                 EVT MemVT, EVT VT, SDValue Chain, SDValue Ptr,
                                 MachineMemOperand *MMO);
 
  /// Creates a MemIntrinsicNode that may produce a
  /// result and takes a list of operands. Opcode may be INTRINSIC_VOID,
  /// INTRINSIC_W_CHAIN, or a target-specific memory-referencing opcode
  // (see `SelectionDAGTargetInfo::isTargetMemoryOpcode`).
  LLVM_ABI SDValue getMemIntrinsicNode(
      unsigned Opcode, const SDLoc &dl, SDVTList VTList, ArrayRef<SDValue> Ops,
      EVT MemVT, MachinePointerInfo PtrInfo, Align Alignment,
      MachineMemOperand::Flags Flags = MachineMemOperand::MOLoad |
                                       MachineMemOperand::MOStore,
      LocationSize Size = LocationSize::precise(0),
      const AAMDNodes &AAInfo = AAMDNodes());
 
  inline SDValue getMemIntrinsicNode(
      unsigned Opcode, const SDLoc &dl, SDVTList VTList, ArrayRef<SDValue> Ops,
      EVT MemVT, MachinePointerInfo PtrInfo,
      MaybeAlign Alignment = std::nullopt,
      MachineMemOperand::Flags Flags = MachineMemOperand::MOLoad |
                                       MachineMemOperand::MOStore,
      LocationSize Size = LocationSize::precise(0),
      const AAMDNodes &AAInfo = AAMDNodes()) {
    // Ensure that codegen never sees alignment 0
    return getMemIntrinsicNode(Opcode, dl, VTList, Ops, MemVT, PtrInfo,
                               Alignment.value_or(getEVTAlign(MemVT)), Flags,
                               Size, AAInfo);
  }
 
  LLVM_ABI SDValue getMemIntrinsicNode(unsigned Opcode, const SDLoc &dl,
                                       SDVTList VTList, ArrayRef<SDValue> Ops,
                                       EVT MemVT, MachineMemOperand *MMO);
 
  /// getMemIntrinsicNode - Creates a MemIntrinsicNode with multiple MMOs.
  LLVM_ABI SDValue getMemIntrinsicNode(unsigned Opcode, const SDLoc &dl,
                                       SDVTList VTList, ArrayRef<SDValue> Ops,
                                       EVT MemVT,
                                       ArrayRef<MachineMemOperand *> MMOs);
 
  /// Creates a LifetimeSDNode that starts (`IsStart==true`) or ends
  /// (`IsStart==false`) the lifetime of the `FrameIndex`.
  LLVM_ABI SDValue getLifetimeNode(bool IsStart, const SDLoc &dl, SDValue Chain,
                                   int FrameIndex);
 
  /// Creates a PseudoProbeSDNode with function GUID `Guid` and
  /// the index of the block `Index` it is probing, as well as the attributes
  /// `attr` of the probe.
  LLVM_ABI SDValue getPseudoProbeNode(const SDLoc &Dl, SDValue Chain,
                                      uint64_t Guid, uint64_t Index,
                                      uint32_t Attr);
 
  /// Create a MERGE_VALUES node from the given operands.
  LLVM_ABI SDValue getMergeValues(ArrayRef<SDValue> Ops, const SDLoc &dl);
 
  /// Return poison values for each of \p ResultTypes, substituting \p Chain
  /// for any result of type MVT::Other, merged into a single MERGE_VALUES
  /// node. Used to salvage a chain when an operation cannot be lowered due
  /// to an error, and the program will be discarded.
  LLVM_ABI SDValue getErrorMergeValues(ArrayRef<EVT> ResultTypes, SDValue Chain,
                                       const SDLoc &dl);
 
  /// Loads are not normal binary operators: their result type is not
  /// determined by their operands, and they produce a value AND a token chain.
  ///
  /// This function will set the MOLoad flag on MMOFlags, but you can set it if
  /// you want.  The MOStore flag must not be set.
  LLVM_ABI SDValue
  getLoad(EVT VT, const SDLoc &dl, SDValue Chain, SDValue Ptr,
          MachinePointerInfo PtrInfo, MaybeAlign Alignment = MaybeAlign(),
          MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
          const MMOMetadata &Metadata = MMOMetadata());
  LLVM_ABI SDValue getLoad(EVT VT, const SDLoc &dl, SDValue Chain, SDValue Ptr,
                           MachineMemOperand *MMO);
  LLVM_ABI SDValue
  getExtLoad(ISD::LoadExtType ExtType, const SDLoc &dl, EVT VT, SDValue Chain,
             SDValue Ptr, MachinePointerInfo PtrInfo, EVT MemVT,
             MaybeAlign Alignment = MaybeAlign(),
             MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
             const MMOMetadata &Metadata = MMOMetadata());
  LLVM_ABI SDValue getExtLoad(ISD::LoadExtType ExtType, const SDLoc &dl, EVT VT,
                              SDValue Chain, SDValue Ptr, EVT MemVT,
                              MachineMemOperand *MMO);
  LLVM_ABI SDValue getIndexedLoad(SDValue OrigLoad, const SDLoc &dl,
                                  SDValue Base, SDValue Offset,
                                  ISD::MemIndexedMode AM);
  LLVM_ABI SDValue
  getLoad(ISD::MemIndexedMode AM, ISD::LoadExtType ExtType, EVT VT,
          const SDLoc &dl, SDValue Chain, SDValue Ptr, SDValue Offset,
          MachinePointerInfo PtrInfo, EVT MemVT, Align Alignment,
          MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
          const MMOMetadata &Metadata = MMOMetadata());
  inline SDValue
  getLoad(ISD::MemIndexedMode AM, ISD::LoadExtType ExtType, EVT VT,
          const SDLoc &dl, SDValue Chain, SDValue Ptr, SDValue Offset,
          MachinePointerInfo PtrInfo, EVT MemVT,
          MaybeAlign Alignment = MaybeAlign(),
          MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
          const MMOMetadata &Metadata = MMOMetadata()) {
    // Ensures that codegen never sees a None Alignment.
    return getLoad(AM, ExtType, VT, dl, Chain, Ptr, Offset, PtrInfo, MemVT,
                   Alignment.value_or(getEVTAlign(MemVT)), MMOFlags, Metadata);
  }
  LLVM_ABI SDValue getLoad(ISD::MemIndexedMode AM, ISD::LoadExtType ExtType,
                           EVT VT, const SDLoc &dl, SDValue Chain, SDValue Ptr,
                           SDValue Offset, EVT MemVT, MachineMemOperand *MMO);
 
  /// Helper function to build ISD::STORE nodes.
  ///
  /// This function will set the MOStore flag on MMOFlags, but you can set it if
  /// you want.  The MOLoad and MOInvariant flags must not be set.
 
  LLVM_ABI SDValue
  getStore(SDValue Chain, const SDLoc &dl, SDValue Val, SDValue Ptr,
           MachinePointerInfo PtrInfo, Align Alignment,
           MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
           const MMOMetadata &Metadata = MMOMetadata());
  inline SDValue
  getStore(SDValue Chain, const SDLoc &dl, SDValue Val, SDValue Ptr,
           MachinePointerInfo PtrInfo, MaybeAlign Alignment = MaybeAlign(),
           MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
           const MMOMetadata &Metadata = MMOMetadata()) {
    return getStore(Chain, dl, Val, Ptr, PtrInfo,
                    Alignment.value_or(getEVTAlign(Val.getValueType())),
                    MMOFlags, Metadata);
  }
  LLVM_ABI SDValue getStore(SDValue Chain, const SDLoc &dl, SDValue Val,
                            SDValue Ptr, MachineMemOperand *MMO);
  LLVM_ABI SDValue getTruncStore(
      SDValue Chain, const SDLoc &dl, SDValue Val, SDValue Ptr, SDValue Offset,
      MachinePointerInfo PtrInfo, EVT SVT, Align Alignment,
      MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
      const MMOMetadata &Metadata = MMOMetadata());
  LLVM_ABI SDValue
  getTruncStore(SDValue Chain, const SDLoc &dl, SDValue Val, SDValue Ptr,
                MachinePointerInfo PtrInfo, EVT SVT, Align Alignment,
                MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
                const MMOMetadata &Metadata = MMOMetadata());
  LLVM_ABI SDValue getTruncStore(SDValue Chain, const SDLoc &dl, SDValue Val,
                                 SDValue Ptr, SDValue Offset, EVT SVT,
                                 MachineMemOperand *MMO);
 
  inline SDValue
  getTruncStore(SDValue Chain, const SDLoc &dl, SDValue Val, SDValue Ptr,
                MachinePointerInfo PtrInfo, EVT SVT,
                MaybeAlign Alignment = MaybeAlign(),
                MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
                const MMOMetadata &Metadata = MMOMetadata()) {
    return getTruncStore(Chain, dl, Val, Ptr, PtrInfo, SVT,
                         Alignment.value_or(getEVTAlign(SVT)), MMOFlags,
                         Metadata);
  }
  LLVM_ABI SDValue getTruncStore(SDValue Chain, const SDLoc &dl, SDValue Val,
                                 SDValue Ptr, EVT SVT, MachineMemOperand *MMO);
  LLVM_ABI SDValue getIndexedStore(SDValue OrigStore, const SDLoc &dl,
                                   SDValue Base, SDValue Offset,
                                   ISD::MemIndexedMode AM);
  LLVM_ABI SDValue getStore(SDValue Chain, const SDLoc &dl, SDValue Val,
                            SDValue Ptr, SDValue Offset, EVT SVT,
                            MachineMemOperand *MMO, ISD::MemIndexedMode AM,
                            bool IsTruncating = false);
 
  LLVM_ABI SDValue getLoadVP(ISD::MemIndexedMode AM, ISD::LoadExtType ExtType,
                             EVT VT, const SDLoc &dl, SDValue Chain,
                             SDValue Ptr, SDValue Offset, SDValue Mask,
                             SDValue EVL, MachinePointerInfo PtrInfo, EVT MemVT,
                             Align Alignment, MachineMemOperand::Flags MMOFlags,
                             const AAMDNodes &AAInfo,
                             const MDNode *Ranges = nullptr,
                             bool IsExpanding = false);
  inline SDValue
  getLoadVP(ISD::MemIndexedMode AM, ISD::LoadExtType ExtType, EVT VT,
            const SDLoc &dl, SDValue Chain, SDValue Ptr, SDValue Offset,
            SDValue Mask, SDValue EVL, MachinePointerInfo PtrInfo, EVT MemVT,
            MaybeAlign Alignment = MaybeAlign(),
            MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
            const AAMDNodes &AAInfo = AAMDNodes(),
            const MDNode *Ranges = nullptr, bool IsExpanding = false) {
    // Ensures that codegen never sees a None Alignment.
    return getLoadVP(AM, ExtType, VT, dl, Chain, Ptr, Offset, Mask, EVL,
                     PtrInfo, MemVT, Alignment.value_or(getEVTAlign(MemVT)),
                     MMOFlags, AAInfo, Ranges, IsExpanding);
  }
  LLVM_ABI SDValue getLoadVP(ISD::MemIndexedMode AM, ISD::LoadExtType ExtType,
                             EVT VT, const SDLoc &dl, SDValue Chain,
                             SDValue Ptr, SDValue Offset, SDValue Mask,
                             SDValue EVL, EVT MemVT, MachineMemOperand *MMO,
                             bool IsExpanding = false);
  LLVM_ABI SDValue getLoadVP(EVT VT, const SDLoc &dl, SDValue Chain,
                             SDValue Ptr, SDValue Mask, SDValue EVL,
                             MachinePointerInfo PtrInfo, MaybeAlign Alignment,
                             MachineMemOperand::Flags MMOFlags,
                             const AAMDNodes &AAInfo,
                             const MDNode *Ranges = nullptr,
                             bool IsExpanding = false);
  LLVM_ABI SDValue getLoadVP(EVT VT, const SDLoc &dl, SDValue Chain,
                             SDValue Ptr, SDValue Mask, SDValue EVL,
                             MachineMemOperand *MMO, bool IsExpanding = false);
  LLVM_ABI SDValue getExtLoadVP(
      ISD::LoadExtType ExtType, const SDLoc &dl, EVT VT, SDValue Chain,
      SDValue Ptr, SDValue Mask, SDValue EVL, MachinePointerInfo PtrInfo,
      EVT MemVT, MaybeAlign Alignment, MachineMemOperand::Flags MMOFlags,
      const AAMDNodes &AAInfo, bool IsExpanding = false);
  LLVM_ABI SDValue getExtLoadVP(ISD::LoadExtType ExtType, const SDLoc &dl,
                                EVT VT, SDValue Chain, SDValue Ptr,
                                SDValue Mask, SDValue EVL, EVT MemVT,
                                MachineMemOperand *MMO,
                                bool IsExpanding = false);
  LLVM_ABI SDValue getStoreVP(SDValue Chain, const SDLoc &dl, SDValue Val,
                              SDValue Ptr, SDValue Offset, SDValue Mask,
                              SDValue EVL, EVT MemVT, MachineMemOperand *MMO,
                              ISD::MemIndexedMode AM, bool IsTruncating = false,
                              bool IsCompressing = false);
  LLVM_ABI SDValue getTruncStoreVP(SDValue Chain, const SDLoc &dl, SDValue Val,
                                   SDValue Ptr, SDValue Mask, SDValue EVL,
                                   MachinePointerInfo PtrInfo, EVT SVT,
                                   Align Alignment,
                                   MachineMemOperand::Flags MMOFlags,
                                   const AAMDNodes &AAInfo,
                                   bool IsCompressing = false);
  LLVM_ABI SDValue getTruncStoreVP(SDValue Chain, const SDLoc &dl, SDValue Val,
                                   SDValue Ptr, SDValue Mask, SDValue EVL,
                                   EVT SVT, MachineMemOperand *MMO,
                                   bool IsCompressing = false);
 
  LLVM_ABI SDValue getStridedLoadVP(
      ISD::MemIndexedMode AM, ISD::LoadExtType ExtType, EVT VT, const SDLoc &DL,
      SDValue Chain, SDValue Ptr, SDValue Offset, SDValue Stride, SDValue Mask,
      SDValue EVL, EVT MemVT, MachineMemOperand *MMO, bool IsExpanding = false);
  LLVM_ABI SDValue getStridedLoadVP(EVT VT, const SDLoc &DL, SDValue Chain,
                                    SDValue Ptr, SDValue Stride, SDValue Mask,
                                    SDValue EVL, MachineMemOperand *MMO,
                                    bool IsExpanding = false);
  LLVM_ABI SDValue getExtStridedLoadVP(ISD::LoadExtType ExtType,
                                       const SDLoc &DL, EVT VT, SDValue Chain,
                                       SDValue Ptr, SDValue Stride,
                                       SDValue Mask, SDValue EVL, EVT MemVT,
                                       MachineMemOperand *MMO,
                                       bool IsExpanding = false);
  LLVM_ABI SDValue getStridedStoreVP(SDValue Chain, const SDLoc &DL,
                                     SDValue Val, SDValue Ptr, SDValue Offset,
                                     SDValue Stride, SDValue Mask, SDValue EVL,
                                     EVT MemVT, MachineMemOperand *MMO,
                                     ISD::MemIndexedMode AM,
                                     bool IsTruncating = false,
                                     bool IsCompressing = false);
 
  LLVM_ABI SDValue getGatherVP(SDVTList VTs, EVT VT, const SDLoc &dl,
                               ArrayRef<SDValue> Ops, MachineMemOperand *MMO,
                               ISD::MemIndexType IndexType);
  LLVM_ABI SDValue getScatterVP(SDVTList VTs, EVT VT, const SDLoc &dl,
                                ArrayRef<SDValue> Ops, MachineMemOperand *MMO,
                                ISD::MemIndexType IndexType);
 
  LLVM_ABI SDValue getMaskedLoad(EVT VT, const SDLoc &dl, SDValue Chain,
                                 SDValue Base, SDValue Offset, SDValue Mask,
                                 SDValue Src0, EVT MemVT,
                                 MachineMemOperand *MMO, ISD::MemIndexedMode AM,
                                 ISD::LoadExtType, bool IsExpanding = false);
  LLVM_ABI SDValue getIndexedMaskedLoad(SDValue OrigLoad, const SDLoc &dl,
                                        SDValue Base, SDValue Offset,
                                        ISD::MemIndexedMode AM);
  LLVM_ABI SDValue getMaskedStore(SDValue Chain, const SDLoc &dl, SDValue Val,
                                  SDValue Base, SDValue Offset, SDValue Mask,
                                  EVT MemVT, MachineMemOperand *MMO,
                                  ISD::MemIndexedMode AM,
                                  bool IsTruncating = false,
                                  bool IsCompressing = false);
  LLVM_ABI SDValue getIndexedMaskedStore(SDValue OrigStore, const SDLoc &dl,
                                         SDValue Base, SDValue Offset,
                                         ISD::MemIndexedMode AM);
  LLVM_ABI SDValue getMaskedGather(SDVTList VTs, EVT MemVT, const SDLoc &dl,
                                   ArrayRef<SDValue> Ops,
                                   MachineMemOperand *MMO,
                                   ISD::MemIndexType IndexType,
                                   ISD::LoadExtType ExtTy);
  LLVM_ABI SDValue getMaskedScatter(SDVTList VTs, EVT MemVT, const SDLoc &dl,
                                    ArrayRef<SDValue> Ops,
                                    MachineMemOperand *MMO,
                                    ISD::MemIndexType IndexType,
                                    bool IsTruncating = false);
  LLVM_ABI SDValue getMaskedHistogram(SDVTList VTs, EVT MemVT, const SDLoc &dl,
                                      ArrayRef<SDValue> Ops,
                                      MachineMemOperand *MMO,
                                      ISD::MemIndexType IndexType);
  LLVM_ABI SDValue getLoadFFVP(EVT VT, const SDLoc &DL, SDValue Chain,
                               SDValue Ptr, SDValue Mask, SDValue EVL,
                               MachineMemOperand *MMO);
 
  LLVM_ABI SDValue getGetFPEnv(SDValue Chain, const SDLoc &dl, SDValue Ptr,
                               EVT MemVT, MachineMemOperand *MMO);
  LLVM_ABI SDValue getSetFPEnv(SDValue Chain, const SDLoc &dl, SDValue Ptr,
                               EVT MemVT, MachineMemOperand *MMO);
 
  /// Construct a node to track a Value* through the backend.
  LLVM_ABI SDValue getSrcValue(const Value *v);
 
  /// Return an MDNodeSDNode which holds an MDNode.
  LLVM_ABI SDValue getMDNode(const MDNode *MD);
 
  /// Return a bitcast using the SDLoc of the value operand, and casting to the
  /// provided type. Use getNode to set a custom SDLoc.
  LLVM_ABI SDValue getBitcast(EVT VT, SDValue V);
 
  /// Return an AddrSpaceCastSDNode.
  LLVM_ABI SDValue getAddrSpaceCast(const SDLoc &dl, EVT VT, SDValue Ptr,
                                    unsigned SrcAS, unsigned DestAS,
                                    const SDNodeFlags Flags = SDNodeFlags());
 
  /// Return a freeze using the SDLoc of the value operand.
  LLVM_ABI SDValue getFreeze(SDValue V);
 
  /// Return a freeze of V if any of the demanded elts may be undef or poison.
  /// \p Kind can be used to selectively freeze poison and/or undef bits only.
  LLVM_ABI SDValue
  getFreeze(SDValue V, const APInt &DemandedElts,
            UndefPoisonKind Kind = UndefPoisonKind::UndefOrPoison);
 
  /// Return an AssertAlignSDNode.
  LLVM_ABI SDValue getAssertAlign(const SDLoc &DL, SDValue V, Align A);
 
  /// Swap N1 and N2 if Opcode is a commutative binary opcode
  /// and the canonical form expects the opposite order.
  LLVM_ABI void canonicalizeCommutativeBinop(unsigned Opcode, SDValue &N1,
                                             SDValue &N2) const;
 
  /// Return the specified value casted to
  /// the target's desired shift amount type.
  LLVM_ABI SDValue getShiftAmountOperand(EVT LHSTy, SDValue Op);
 
  /// Expand the specified \c ISD::VAARG node as the Legalize pass would.
  LLVM_ABI SDValue expandVAArg(SDNode *Node);
 
  /// Expand the specified \c ISD::VACOPY node as the Legalize pass would.
  LLVM_ABI SDValue expandVACopy(SDNode *Node);
 
  /// Return a GlobalAddress of the function from the current module with
  /// name matching the given ExternalSymbol. Additionally can provide the
  /// matched function.
  /// Panic if the function doesn't exist.
  LLVM_ABI SDValue getSymbolFunctionGlobalAddress(
      SDValue Op, Function **TargetFunction = nullptr);
 
  /// *Mutate* the specified node in-place to have the
  /// specified operands.  If the resultant node already exists in the DAG,
  /// this does not modify the specified node, instead it returns the node that
  /// already exists.  If the resultant node does not exist in the DAG, the
  /// input node is returned.  As a degenerate case, if you specify the same
  /// input operands as the node already has, the input node is returned.
  LLVM_ABI SDNode *UpdateNodeOperands(SDNode *N, SDValue Op);
  LLVM_ABI SDNode *UpdateNodeOperands(SDNode *N, SDValue Op1, SDValue Op2);
  LLVM_ABI SDNode *UpdateNodeOperands(SDNode *N, SDValue Op1, SDValue Op2,
                                      SDValue Op3);
  LLVM_ABI SDNode *UpdateNodeOperands(SDNode *N, SDValue Op1, SDValue Op2,
                                      SDValue Op3, SDValue Op4);
  LLVM_ABI SDNode *UpdateNodeOperands(SDNode *N, SDValue Op1, SDValue Op2,
                                      SDValue Op3, SDValue Op4, SDValue Op5);
  LLVM_ABI SDNode *UpdateNodeOperands(SDNode *N, ArrayRef<SDValue> Ops);
 
  /// Creates a new TokenFactor containing \p Vals. If \p Vals contains 64k
  /// values or more, move values into new TokenFactors in 64k-1 blocks, until
  /// the final TokenFactor has less than 64k operands.
  LLVM_ABI SDValue getTokenFactor(const SDLoc &DL,
                                  SmallVectorImpl<SDValue> &Vals);
 
  /// *Mutate* the specified machine node's memory references to the provided
  /// list.
  LLVM_ABI void setNodeMemRefs(MachineSDNode *N,
                               ArrayRef<MachineMemOperand *> NewMemRefs);
 
  // Calculate divergence of node \p N based on its operands.
  LLVM_ABI bool calculateDivergence(SDNode *N);
 
  // Propagates the change in divergence to users
  LLVM_ABI void updateDivergence(SDNode *N);
 
  /// These are used for target selectors to *mutate* the
  /// specified node to have the specified return type, Target opcode, and
  /// operands.  Note that target opcodes are stored as
  /// ~TargetOpcode in the node opcode field.  The resultant node is returned.
  LLVM_ABI SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT);
  LLVM_ABI SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT,
                                SDValue Op1);
  LLVM_ABI SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT,
                                SDValue Op1, SDValue Op2);
  LLVM_ABI SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT,
                                SDValue Op1, SDValue Op2, SDValue Op3);
  LLVM_ABI SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT,
                                ArrayRef<SDValue> Ops);
  LLVM_ABI SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT1,
                                EVT VT2);
  LLVM_ABI SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT1,
                                EVT VT2, ArrayRef<SDValue> Ops);
  LLVM_ABI SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT1,
                                EVT VT2, EVT VT3, ArrayRef<SDValue> Ops);
  LLVM_ABI SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT1,
                                EVT VT2, SDValue Op1, SDValue Op2);
  LLVM_ABI SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, SDVTList VTs,
                                ArrayRef<SDValue> Ops);
 
  /// This *mutates* the specified node to have the specified
  /// return type, opcode, and operands.
  LLVM_ABI SDNode *MorphNodeTo(SDNode *N, unsigned Opc, SDVTList VTs,
                               ArrayRef<SDValue> Ops);
 
  /// Mutate the specified strict FP node to its non-strict equivalent,
  /// unlinking the node from its chain and dropping the metadata arguments.
  /// The node must be a strict FP node.
  LLVM_ABI SDNode *mutateStrictFPToFP(SDNode *Node);
 
  /// These are used for target selectors to create a new node
  /// with specified return type(s), MachineInstr opcode, and operands.
  ///
  /// Note that getMachineNode returns the resultant node.  If there is already
  /// a node of the specified opcode and operands, it returns that node instead
  /// of the current one.
  LLVM_ABI MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                                         EVT VT);
  LLVM_ABI MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                                         EVT VT, SDValue Op1);
  LLVM_ABI MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                                         EVT VT, SDValue Op1, SDValue Op2);
  LLVM_ABI MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                                         EVT VT, SDValue Op1, SDValue Op2,
                                         SDValue Op3);
  LLVM_ABI MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                                         EVT VT, ArrayRef<SDValue> Ops);
  LLVM_ABI MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                                         EVT VT1, EVT VT2, SDValue Op1,
                                         SDValue Op2);
  LLVM_ABI MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                                         EVT VT1, EVT VT2, SDValue Op1,
                                         SDValue Op2, SDValue Op3);
  LLVM_ABI MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                                         EVT VT1, EVT VT2,
                                         ArrayRef<SDValue> Ops);
  LLVM_ABI MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                                         EVT VT1, EVT VT2, EVT VT3, SDValue Op1,
                                         SDValue Op2);
  LLVM_ABI MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                                         EVT VT1, EVT VT2, EVT VT3, SDValue Op1,
                                         SDValue Op2, SDValue Op3);
  LLVM_ABI MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                                         EVT VT1, EVT VT2, EVT VT3,
                                         ArrayRef<SDValue> Ops);
  LLVM_ABI MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                                         ArrayRef<EVT> ResultTys,
                                         ArrayRef<SDValue> Ops);
  LLVM_ABI MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                                         SDVTList VTs, ArrayRef<SDValue> Ops);
 
  /// A convenience function for creating TargetInstrInfo::EXTRACT_SUBREG nodes.
  LLVM_ABI SDValue getTargetExtractSubreg(int SRIdx, const SDLoc &DL, EVT VT,
                                          SDValue Operand);
 
  /// A convenience function for creating TargetInstrInfo::INSERT_SUBREG nodes.
  LLVM_ABI SDValue getTargetInsertSubreg(int SRIdx, const SDLoc &DL, EVT VT,
                                         SDValue Operand, SDValue Subreg);
 
  /// Get the specified node if it's already available, or else return NULL.
  LLVM_ABI SDNode *getNodeIfExists(unsigned Opcode, SDVTList VTList,
                                   ArrayRef<SDValue> Ops,
                                   const SDNodeFlags Flags,
                                   bool AllowCommute = false);
  LLVM_ABI SDNode *getNodeIfExists(unsigned Opcode, SDVTList VTList,
                                   ArrayRef<SDValue> Ops,
                                   bool AllowCommute = false);
 
  /// Check if a node exists without modifying its flags.
  LLVM_ABI bool doesNodeExist(unsigned Opcode, SDVTList VTList,
                              ArrayRef<SDValue> Ops);
 
  /// Creates a SDDbgValue node.
  LLVM_ABI SDDbgValue *getDbgValue(DIVariable *Var, DIExpression *Expr,
                                   SDNode *N, unsigned R, bool IsIndirect,
                                   const DebugLoc &DL, unsigned O);
 
  /// Creates a constant SDDbgValue node.
  LLVM_ABI SDDbgValue *getConstantDbgValue(DIVariable *Var, DIExpression *Expr,
                                           const Value *C, const DebugLoc &DL,
                                           unsigned O);
 
  /// Creates a FrameIndex SDDbgValue node.
  LLVM_ABI SDDbgValue *getFrameIndexDbgValue(DIVariable *Var,
                                             DIExpression *Expr, unsigned FI,
                                             bool IsIndirect,
                                             const DebugLoc &DL, unsigned O);
 
  /// Creates a FrameIndex SDDbgValue node.
  LLVM_ABI SDDbgValue *getFrameIndexDbgValue(DIVariable *Var,
                                             DIExpression *Expr, unsigned FI,
                                             ArrayRef<SDNode *> Dependencies,
                                             bool IsIndirect,
                                             const DebugLoc &DL, unsigned O);
 
  /// Creates a VReg SDDbgValue node.
  LLVM_ABI SDDbgValue *getVRegDbgValue(DIVariable *Var, DIExpression *Expr,
                                       Register VReg, bool IsIndirect,
                                       const DebugLoc &DL, unsigned O);
 
  /// Creates a SDDbgValue node from a list of locations.
  LLVM_ABI SDDbgValue *getDbgValueList(DIVariable *Var, DIExpression *Expr,
                                       ArrayRef<SDDbgOperand> Locs,
                                       ArrayRef<SDNode *> Dependencies,
                                       bool IsIndirect, const DebugLoc &DL,
                                       unsigned O, bool IsVariadic);
 
  /// Creates a SDDbgLabel node.
  LLVM_ABI SDDbgLabel *getDbgLabel(DILabel *Label, const DebugLoc &DL,
                                   unsigned O);
 
  /// Transfer debug values from one node to another, while optionally
  /// generating fragment expressions for split-up values. If \p InvalidateDbg
  /// is set, debug values are invalidated after they are transferred.
  LLVM_ABI void transferDbgValues(SDValue From, SDValue To,
                                  unsigned OffsetInBits = 0,
                                  unsigned SizeInBits = 0,
                                  bool InvalidateDbg = true);
 
  /// Remove the specified node from the system. If any of its
  /// operands then becomes dead, remove them as well. Inform UpdateListener
  /// for each node deleted.
  LLVM_ABI void RemoveDeadNode(SDNode *N);
 
  /// This method deletes the unreachable nodes in the
  /// given list, and any nodes that become unreachable as a result.
  LLVM_ABI void RemoveDeadNodes(SmallVectorImpl<SDNode *> &DeadNodes);
 
  /// Modify anything using 'From' to use 'To' instead.
  /// This can cause recursive merging of nodes in the DAG.  Use the first
  /// version if 'From' is known to have a single result, use the second
  /// if you have two nodes with identical results (or if 'To' has a superset
  /// of the results of 'From'), use the third otherwise.
  ///
  /// These methods all take an optional UpdateListener, which (if not null) is
  /// informed about nodes that are deleted and modified due to recursive
  /// changes in the dag.
  ///
  /// These functions only replace all existing uses. It's possible that as
  /// these replacements are being performed, CSE may cause the From node
  /// to be given new uses. These new uses of From are left in place, and
  /// not automatically transferred to To.
  ///
  LLVM_ABI void ReplaceAllUsesWith(SDValue From, SDValue To);
  LLVM_ABI void ReplaceAllUsesWith(SDNode *From, SDNode *To);
  LLVM_ABI void ReplaceAllUsesWith(SDNode *From, const SDValue *To);
 
  /// Replace any uses of From with To, leaving
  /// uses of other values produced by From.getNode() alone.
  LLVM_ABI void ReplaceAllUsesOfValueWith(SDValue From, SDValue To);
 
  /// Like ReplaceAllUsesOfValueWith, but for multiple values at once.
  /// This correctly handles the case where
  /// there is an overlap between the From values and the To values.
  LLVM_ABI void ReplaceAllUsesOfValuesWith(const SDValue *From,
                                           const SDValue *To, unsigned Num);
 
  /// If an existing load has uses of its chain, create a token factor node with
  /// that chain and the new memory node's chain and update users of the old
  /// chain to the token factor. This ensures that the new memory node will have
  /// the same relative memory dependency position as the old load. Returns the
  /// new merged load chain.
  LLVM_ABI SDValue makeEquivalentMemoryOrdering(SDValue OldChain,
                                                SDValue NewMemOpChain);
 
  /// If an existing load has uses of its chain, create a token factor node with
  /// that chain and the new memory node's chain and update users of the old
  /// chain to the token factor. This ensures that the new memory node will have
  /// the same relative memory dependency position as the old load. Returns the
  /// new merged load chain.
  LLVM_ABI SDValue makeEquivalentMemoryOrdering(LoadSDNode *OldLoad,
                                                SDValue NewMemOp);
 
  /// Get all the nodes in their topological order without modifying any states.
  LLVM_ABI void getTopologicallyOrderedNodes(
      SmallVectorImpl<const SDNode *> &SortedNodes) const;
 
  /// Topological-sort the AllNodes list and a
  /// assign a unique node id for each node in the DAG based on their
  /// topological order. Returns the number of nodes.
  LLVM_ABI unsigned AssignTopologicalOrder();
 
  /// Move node N in the AllNodes list to be immediately
  /// before the given iterator Position. This may be used to update the
  /// topological ordering when the list of nodes is modified.
  void RepositionNode(allnodes_iterator Position, SDNode *N) {
    AllNodes.insert(Position, AllNodes.remove(N));
  }
 
  /// Add a dbg_value SDNode. If SD is non-null that means the
  /// value is produced by SD.
  LLVM_ABI void AddDbgValue(SDDbgValue *DB, bool isParameter);
 
  /// Add a dbg_label SDNode.
  LLVM_ABI void AddDbgLabel(SDDbgLabel *DB);
 
  /// Get the debug values which reference the given SDNode.
  ArrayRef<SDDbgValue*> GetDbgValues(const SDNode* SD) const {
    return DbgInfo->getSDDbgValues(SD);
  }
 
public:
  /// Return true if there are any SDDbgValue nodes associated
  /// with this SelectionDAG.
  bool hasDebugValues() const { return !DbgInfo->empty(); }
 
  SDDbgInfo::DbgIterator DbgBegin() const { return DbgInfo->DbgBegin(); }
  SDDbgInfo::DbgIterator DbgEnd() const  { return DbgInfo->DbgEnd(); }
 
  SDDbgInfo::DbgIterator ByvalParmDbgBegin() const {
    return DbgInfo->ByvalParmDbgBegin();
  }
  SDDbgInfo::DbgIterator ByvalParmDbgEnd() const {
    return DbgInfo->ByvalParmDbgEnd();
  }
 
  SDDbgInfo::DbgLabelIterator DbgLabelBegin() const {
    return DbgInfo->DbgLabelBegin();
  }
  SDDbgInfo::DbgLabelIterator DbgLabelEnd() const {
    return DbgInfo->DbgLabelEnd();
  }
 
  /// To be invoked on an SDNode that is slated to be erased. This
  /// function mirrors \c llvm::salvageDebugInfo.
  LLVM_ABI void salvageDebugInfo(SDNode &N);
 
  /// Dump the textual format of this DAG. Nodes are not sorted.
  /// Note that we overload it instead of using default value so that it is
  /// convenient to be called from debuggers.
  LLVM_ABI void dump() const;
 
  /// Dump the textual format of this DAG. Print nodes in sorted orders if \p
  /// Sorted is true.
  LLVM_ABI void dump(bool Sorted) const;
 
  /// In most cases this function returns the ABI alignment for a given type,
  /// except for illegal vector types where the alignment exceeds that of the
  /// stack. In such cases we attempt to break the vector down to a legal type
  /// and return the ABI alignment for that instead.
  LLVM_ABI Align getReducedAlign(EVT VT, bool UseABI);
 
  /// Create a stack temporary based on the size in bytes and the alignment
  LLVM_ABI SDValue CreateStackTemporary(TypeSize Bytes, Align Alignment);
 
  /// Create a stack temporary, suitable for holding the specified value type.
  /// If minAlign is specified, the slot size will have at least that alignment.
  LLVM_ABI SDValue CreateStackTemporary(EVT VT, unsigned minAlign = 1);
 
  /// Create a stack temporary suitable for holding either of the specified
  /// value types.
  LLVM_ABI SDValue CreateStackTemporary(EVT VT1, EVT VT2);
 
  /// Emit a store/load combination to the stack. This stores
  /// SrcOp to a stack slot of type SlotVT, truncating it if needed. It then
  /// does a load from the stack slot to DestVT, extending it if needed. The
  /// resultant code need not be legal.
  LLVM_ABI SDValue emitStackConvert(SDValue SrcOp, EVT SlotVT, EVT DestVT,
                                    const SDLoc &DL, SDValue Chain);
 
  LLVM_ABI SDValue FoldSymbolOffset(unsigned Opcode, EVT VT,
                                    const GlobalAddressSDNode *GA,
                                    const SDNode *N2);
 
  LLVM_ABI SDValue FoldConstantArithmetic(unsigned Opcode, const SDLoc &DL,
                                          EVT VT, ArrayRef<SDValue> Ops,
                                          SDNodeFlags Flags = SDNodeFlags());
 
  /// Fold floating-point operations when all operands are constants and/or
  /// undefined.
  LLVM_ABI SDValue foldConstantFPMath(unsigned Opcode, const SDLoc &DL, EVT VT,
                                      ArrayRef<SDValue> Ops);
 
  /// Fold BUILD_VECTOR of constants/undefs to the destination type
  /// BUILD_VECTOR of constants/undefs elements.
  LLVM_ABI SDValue FoldConstantBuildVector(BuildVectorSDNode *BV,
                                           const SDLoc &DL, EVT DstEltVT);
 
  /// Constant fold a setcc to true or false.
  LLVM_ABI SDValue FoldSetCC(EVT VT, SDValue N1, SDValue N2, ISD::CondCode Cond,
                             const SDLoc &dl, SDNodeFlags Flags = {});
 
  /// Return true if the sign bit of Op is known to be zero.
  /// We use this predicate to simplify operations downstream.
  LLVM_ABI bool SignBitIsZero(SDValue Op, unsigned Depth = 0) const;
 
  /// Return true if the sign bit of Op is known to be zero, for a
  /// floating-point value.
  LLVM_ABI bool SignBitIsZeroFP(SDValue Op, unsigned Depth = 0) const;
 
  /// Return true if 'Op & Mask' is known to be zero.  We
  /// use this predicate to simplify operations downstream.  Op and Mask are
  /// known to be the same type.
  LLVM_ABI bool MaskedValueIsZero(SDValue Op, const APInt &Mask,
                                  unsigned Depth = 0) const;
 
  /// Return true if 'Op & Mask' is known to be zero in DemandedElts.  We
  /// use this predicate to simplify operations downstream.  Op and Mask are
  /// known to be the same type.
  LLVM_ABI bool MaskedValueIsZero(SDValue Op, const APInt &Mask,
                                  const APInt &DemandedElts,
                                  unsigned Depth = 0) const;
 
  /// Return true if 'Op' is known to be zero in DemandedElts.  We
  /// use this predicate to simplify operations downstream.
  LLVM_ABI bool MaskedVectorIsZero(SDValue Op, const APInt &DemandedElts,
                                   unsigned Depth = 0) const;
 
  /// Return true if '(Op & Mask) == Mask'.
  /// Op and Mask are known to be the same type.
  LLVM_ABI bool MaskedValueIsAllOnes(SDValue Op, const APInt &Mask,
                                     unsigned Depth = 0) const;
 
  /// For each demanded element of a vector, see if it is known to be zero.
  LLVM_ABI APInt computeVectorKnownZeroElements(SDValue Op,
                                                const APInt &DemandedElts,
                                                unsigned Depth = 0) const;
 
  /// Determine which bits of Op are known to be either zero or one and return
  /// them in Known. For vectors, the known bits are those that are shared by
  /// every vector element.
  /// Targets can implement the computeKnownBitsForTargetNode method in the
  /// TargetLowering class to allow target nodes to be understood.
  LLVM_ABI KnownBits computeKnownBits(SDValue Op, unsigned Depth = 0) const;
 
  /// Determine which bits of Op are known to be either zero or one and return
  /// them in Known. The DemandedElts argument allows us to only collect the
  /// known bits that are shared by the requested vector elements.
  /// Targets can implement the computeKnownBitsForTargetNode method in the
  /// TargetLowering class to allow target nodes to be understood.
  LLVM_ABI KnownBits computeKnownBits(SDValue Op, const APInt &DemandedElts,
                                      unsigned Depth = 0) const;
 
  /// Determine the possible constant range of an integer or vector of integers.
  LLVM_ABI ConstantRange computeConstantRange(SDValue Op, bool ForSigned,
                                              unsigned Depth = 0) const;
 
  /// Determine the possible constant range of an integer or vector of integers.
  /// The DemandedElts argument allows us to only collect the known ranges that
  /// are shared by the requested vector elements.
  LLVM_ABI ConstantRange computeConstantRange(SDValue Op,
                                              const APInt &DemandedElts,
                                              bool ForSigned,
                                              unsigned Depth = 0) const;
 
  /// Combine constant ranges from computeConstantRange() and
  /// computeKnownBits().
  LLVM_ABI ConstantRange computeConstantRangeIncludingKnownBits(
      SDValue Op, bool ForSigned, unsigned Depth = 0) const;
 
  /// Combine constant ranges from computeConstantRange() and
  /// computeKnownBits(). The DemandedElts argument allows us to only collect
  /// the known ranges that are shared by the requested vector elements.
  LLVM_ABI ConstantRange computeConstantRangeIncludingKnownBits(
      SDValue Op, const APInt &DemandedElts, bool ForSigned,
      unsigned Depth = 0) const;
 
  /// Used to represent the possible overflow behavior of an operation.
  /// Never: the operation cannot overflow.
  /// Always: the operation will always overflow.
  /// Sometime: the operation may or may not overflow.
  enum OverflowKind {
    OFK_Never,
    OFK_Sometime,
    OFK_Always,
  };
 
  /// Determine if the result of the signed addition of 2 nodes can overflow.
  LLVM_ABI OverflowKind computeOverflowForSignedAdd(SDValue N0,
                                                    SDValue N1) const;
 
  /// Determine if the result of the unsigned addition of 2 nodes can overflow.
  LLVM_ABI OverflowKind computeOverflowForUnsignedAdd(SDValue N0,
                                                      SDValue N1) const;
 
  /// Determine if the result of the addition of 2 nodes can overflow.
  OverflowKind computeOverflowForAdd(bool IsSigned, SDValue N0,
                                     SDValue N1) const {
    return IsSigned ? computeOverflowForSignedAdd(N0, N1)
                    : computeOverflowForUnsignedAdd(N0, N1);
  }
 
  /// Determine if the result of the addition of 2 nodes can never overflow.
  bool willNotOverflowAdd(bool IsSigned, SDValue N0, SDValue N1) const {
    return computeOverflowForAdd(IsSigned, N0, N1) == OFK_Never;
  }
 
  /// Determine if the result of the signed sub of 2 nodes can overflow.
  LLVM_ABI OverflowKind computeOverflowForSignedSub(SDValue N0,
                                                    SDValue N1) const;
 
  /// Determine if the result of the unsigned sub of 2 nodes can overflow.
  LLVM_ABI OverflowKind computeOverflowForUnsignedSub(SDValue N0,
                                                      SDValue N1) const;
 
  /// Determine if the result of the sub of 2 nodes can overflow.
  OverflowKind computeOverflowForSub(bool IsSigned, SDValue N0,
                                     SDValue N1) const {
    return IsSigned ? computeOverflowForSignedSub(N0, N1)
                    : computeOverflowForUnsignedSub(N0, N1);
  }
 
  /// Determine if the result of the sub of 2 nodes can never overflow.
  bool willNotOverflowSub(bool IsSigned, SDValue N0, SDValue N1) const {
    return computeOverflowForSub(IsSigned, N0, N1) == OFK_Never;
  }
 
  /// Determine if the result of the signed mul of 2 nodes can overflow.
  LLVM_ABI OverflowKind computeOverflowForSignedMul(SDValue N0,
                                                    SDValue N1) const;
 
  /// Determine if the result of the unsigned mul of 2 nodes can overflow.
  LLVM_ABI OverflowKind computeOverflowForUnsignedMul(SDValue N0,
                                                      SDValue N1) const;
 
  /// Determine if the result of the mul of 2 nodes can overflow.
  OverflowKind computeOverflowForMul(bool IsSigned, SDValue N0,
                                     SDValue N1) const {
    return IsSigned ? computeOverflowForSignedMul(N0, N1)
                    : computeOverflowForUnsignedMul(N0, N1);
  }
 
  /// Determine if the result of the mul of 2 nodes can never overflow.
  bool willNotOverflowMul(bool IsSigned, SDValue N0, SDValue N1) const {
    return computeOverflowForMul(IsSigned, N0, N1) == OFK_Never;
  }
 
  /// Returns true if \p V is an identity element of Opc with Flags.
  /// When OperandNo is 0, it checks that V is a left identity. Otherwise, it
  /// checks that V is a right identity.
  LLVM_ABI bool isIdentityElement(unsigned Opc, SDNodeFlags Flags, SDValue V,
                                  unsigned OperandNo, unsigned Depth = 0) const;
 
  /// Returns true if the demanded vector elements of \p V is an identity
  /// element of Opc with Flags. When OperandNo is 0, it checks that V is a left
  /// identity. Otherwise, it checks that V is a right identity.
  LLVM_ABI bool isIdentityElement(unsigned Opc, SDNodeFlags Flags, SDValue V,
                                  const APInt &DemandedElts, unsigned OperandNo,
                                  unsigned Depth = 0) const;
 
  /// Test if the given value is known to have exactly one bit set. This differs
  /// from computeKnownBits in that it doesn't necessarily determine which bit
  /// is set. If 'OrZero' is set, then return true if the given value is either
  /// a power of two or zero.
  LLVM_ABI bool isKnownToBeAPowerOfTwo(SDValue Val, bool OrZero = false,
                                       unsigned Depth = 0) const;
 
  /// Test if the given value is known to have exactly one bit set. This differs
  /// from computeKnownBits in that it doesn't necessarily determine which bit
  /// is set. The DemandedElts argument allows us to only collect the minimum
  /// sign bits of the requested vector elements. If 'OrZero' is set, then
  /// return true if the given value is either a power of two or zero.
  LLVM_ABI bool isKnownToBeAPowerOfTwo(SDValue Val, const APInt &DemandedElts,
                                       bool OrZero = false,
                                       unsigned Depth = 0) const;
 
  /// Test if the given _fp_ value is known to be an integer power-of-2, either
  /// positive or negative.
  LLVM_ABI bool isKnownToBeAPowerOfTwoFP(SDValue Val, unsigned Depth = 0) const;
 
  /// Return the number of times the sign bit of the register is replicated into
  /// the other bits. We know that at least 1 bit is always equal to the sign
  /// bit (itself), but other cases can give us information. For example,
  /// immediately after an "SRA X, 2", we know that the top 3 bits are all equal
  /// to each other, so we return 3. Targets can implement the
  /// ComputeNumSignBitsForTarget method in the TargetLowering class to allow
  /// target nodes to be understood.
  LLVM_ABI unsigned ComputeNumSignBits(SDValue Op, unsigned Depth = 0) const;
 
  /// Return the number of times the sign bit of the register is replicated into
  /// the other bits. We know that at least 1 bit is always equal to the sign
  /// bit (itself), but other cases can give us information. For example,
  /// immediately after an "SRA X, 2", we know that the top 3 bits are all equal
  /// to each other, so we return 3. The DemandedElts argument allows
  /// us to only collect the minimum sign bits of the requested vector elements.
  /// Targets can implement the ComputeNumSignBitsForTarget method in the
  /// TargetLowering class to allow target nodes to be understood.
  LLVM_ABI unsigned ComputeNumSignBits(SDValue Op, const APInt &DemandedElts,
                                       unsigned Depth = 0) const;
 
  /// Get the upper bound on bit size for this Value \p Op as a signed integer.
  /// i.e.  x == sext(trunc(x to MaxSignedBits) to bitwidth(x)).
  /// Similar to the APInt::getSignificantBits function.
  /// Helper wrapper to ComputeNumSignBits.
  LLVM_ABI unsigned ComputeMaxSignificantBits(SDValue Op,
                                              unsigned Depth = 0) const;
 
  /// Get the upper bound on bit size for this Value \p Op as a signed integer.
  /// i.e.  x == sext(trunc(x to MaxSignedBits) to bitwidth(x)).
  /// Similar to the APInt::getSignificantBits function.
  /// Helper wrapper to ComputeNumSignBits.
  LLVM_ABI unsigned ComputeMaxSignificantBits(SDValue Op,
                                              const APInt &DemandedElts,
                                              unsigned Depth = 0) const;
 
  /// Return true if this function can prove that \p Op is never poison
  /// and, \p Kind can be used to track poison and/or undef bits.
  LLVM_ABI bool isGuaranteedNotToBeUndefOrPoison(
      SDValue Op, UndefPoisonKind Kind = UndefPoisonKind::UndefOrPoison,
      unsigned Depth = 0) const;
 
  /// Return true if this function can prove that \p Op is never poison
  /// and, \p Kind can be used to track poison and/or undef bits. The
  /// DemandedElts argument limits the check to the requested vector elements.
  LLVM_ABI bool isGuaranteedNotToBeUndefOrPoison(
      SDValue Op, const APInt &DemandedElts,
      UndefPoisonKind Kind = UndefPoisonKind::UndefOrPoison,
      unsigned Depth = 0) const;
 
  /// Return true if this function can prove that \p Op is never poison.
  bool isGuaranteedNotToBePoison(SDValue Op, unsigned Depth = 0) const {
    return isGuaranteedNotToBeUndefOrPoison(Op, UndefPoisonKind::PoisonOnly,
                                            Depth);
  }
 
  /// Return true if this function can prove that \p Op is never poison. The
  /// DemandedElts argument limits the check to the requested vector elements.
  bool isGuaranteedNotToBePoison(SDValue Op, const APInt &DemandedElts,
                                 unsigned Depth = 0) const {
    return isGuaranteedNotToBeUndefOrPoison(Op, DemandedElts,
                                            UndefPoisonKind::PoisonOnly, Depth);
  }
 
  /// Return true if Op can create undef or poison from non-undef & non-poison
  /// operands. The DemandedElts argument limits the check to the requested
  /// vector elements.
  ///
  /// \p ConsiderFlags controls whether poison producing flags on the
  /// instruction are considered.  This can be used to see if the instruction
  /// could still introduce undef or poison even without poison generating flags
  /// which might be on the instruction.  (i.e. could the result of
  /// Op->dropPoisonGeneratingFlags() still create poison or undef)
  LLVM_ABI bool
  canCreateUndefOrPoison(SDValue Op, const APInt &DemandedElts,
                         UndefPoisonKind Kind = UndefPoisonKind::UndefOrPoison,
                         bool ConsiderFlags = true, unsigned Depth = 0) const;
 
  /// Return true if Op can create undef or poison from non-undef & non-poison
  /// operands.
  ///
  /// \p ConsiderFlags controls whether poison producing flags on the
  /// instruction are considered.  This can be used to see if the instruction
  /// could still introduce undef or poison even without poison generating flags
  /// which might be on the instruction.  (i.e. could the result of
  /// Op->dropPoisonGeneratingFlags() still create poison or undef)
  LLVM_ABI bool
  canCreateUndefOrPoison(SDValue Op,
                         UndefPoisonKind Kind = UndefPoisonKind::UndefOrPoison,
                         bool ConsiderFlags = true, unsigned Depth = 0) const;
 
  /// Return true if the specified operand is an ISD::OR or ISD::XOR node
  /// that can be treated as an ISD::ADD node.
  /// or(x,y) == add(x,y) iff haveNoCommonBitsSet(x,y)
  /// xor(x,y) == add(x,y) iff isMinSignedConstant(y) && !NoWrap
  /// If \p NoWrap is true, this will not match ISD::XOR.
  LLVM_ABI bool isADDLike(SDValue Op, bool NoWrap = false) const;
 
  /// Return true if the specified operand is an ISD::ADD with a ConstantSDNode
  /// on the right-hand side, or if it is an ISD::OR with a ConstantSDNode that
  /// is guaranteed to have the same semantics as an ADD. This handles the
  /// equivalence:
  ///     X|Cst == X+Cst iff X&Cst = 0.
  LLVM_ABI bool isBaseWithConstantOffset(SDValue Op) const;
 
  /// Determine floating-point class information about \p Op. For vectors, the
  /// known FP classes are those shared by every demanded vector element.
  /// \p InterestedClasses is a hint for which FP classes we care about;
  /// the implementation may bail out early if it can determine that
  /// none of the interested classes are possible.
  LLVM_ABI KnownFPClass computeKnownFPClass(SDValue Op,
                                            FPClassTest InterestedClasses,
                                            unsigned Depth = 0) const;
 
  /// Determine floating-point class information about \p Op. The
  /// DemandedElts argument allows us to only collect the known FP classes
  /// that are shared by the requested vector elements.
  /// \p InterestedClasses is a hint for which FP classes we care about.
  LLVM_ABI KnownFPClass computeKnownFPClass(SDValue Op,
                                            const APInt &DemandedElts,
                                            FPClassTest InterestedClasses,
                                            unsigned Depth = 0) const;
 
  /// Test whether the given SDValue (or all elements of it, if it is a
  /// vector) is known to never be NaN in \p DemandedElts. If \p SNaN is true,
  /// returns if \p Op is known to never be a signaling NaN (it may still be a
  /// qNaN).
  LLVM_ABI bool isKnownNeverNaN(SDValue Op, const APInt &DemandedElts,
                                bool SNaN = false, unsigned Depth = 0) const;
 
  /// Test whether the given SDValue (or all elements of it, if it is a
  /// vector) is known to never be NaN. If \p SNaN is true, returns if \p Op is
  /// known to never be a signaling NaN (it may still be a qNaN).
  LLVM_ABI bool isKnownNeverNaN(SDValue Op, bool SNaN = false,
                                unsigned Depth = 0) const;
 
  /// \returns true if \p Op is known to never be a signaling NaN in \p
  /// DemandedElts.
  bool isKnownNeverSNaN(SDValue Op, const APInt &DemandedElts,
                        unsigned Depth = 0) const {
    return isKnownNeverNaN(Op, DemandedElts, true, Depth);
  }
 
  /// \returns true if \p Op is known to never be a signaling NaN.
  bool isKnownNeverSNaN(SDValue Op, unsigned Depth = 0) const {
    return isKnownNeverNaN(Op, true, Depth);
  }
 
  /// Test whether the given floating point SDValue (or all elements of it, if
  /// it is a vector) is known to never be interpretable as zero in \p
  /// DemandedElts.
  LLVM_ABI bool isKnownNeverLogicalZero(SDValue Op, const APInt &DemandedElts,
                                        unsigned Depth = 0) const;
 
  /// Test whether the given floating point SDValue (or all elements of it, if
  /// it is a vector) is known to never be interpretable as zero.
  LLVM_ABI bool isKnownNeverLogicalZero(SDValue Op, unsigned Depth = 0) const;
 
  /// Test whether the given SDValue is known to contain non-zero value(s).
  LLVM_ABI bool isKnownNeverZero(SDValue Op, unsigned Depth = 0) const;
 
  /// Test whether the given SDValue is known to contain non-zero value(s).
  /// The DemandedElts argument limits the check to the requested vector
  /// elements.
  LLVM_ABI bool isKnownNeverZero(SDValue Op, const APInt &DemandedElts,
                                 unsigned Depth = 0) const;
 
  /// Test whether the given float value is known to be positive. +0.0, +inf and
  /// +nan are considered positive, -0.0, -inf and -nan are not.
  LLVM_ABI bool cannotBeOrderedNegativeFP(SDValue Op) const;
 
  /// Check if a use of a float value is insensitive to signed zeros.
  LLVM_ABI bool canIgnoreSignBitOfZero(const SDUse &Use) const;
 
  /// Check if \p Op has no-signed-zeros, or all users (limited to checking two
  /// for compile-time performance) are insensitive to signed zeros.
  LLVM_ABI bool canIgnoreSignBitOfZero(SDValue Op) const;
 
  /// Test whether two SDValues are known to compare equal. This
  /// is true if they are the same value, or if one is negative zero and the
  /// other positive zero.
  LLVM_ABI bool isEqualTo(SDValue A, SDValue B) const;
 
  /// Return true if A and B have no common bits set. As an example, this can
  /// allow an 'add' to be transformed into an 'or'.
  LLVM_ABI bool haveNoCommonBitsSet(SDValue A, SDValue B) const;
 
  /// Test whether \p V has a splatted value for all the demanded elements.
  ///
  /// On success \p UndefElts will indicate the elements that have UNDEF
  /// values instead of the splat value, this is only guaranteed to be correct
  /// for \p DemandedElts.
  ///
  /// NOTE: The function will return true for a demanded splat of UNDEF values.
  LLVM_ABI bool isSplatValue(SDValue V, const APInt &DemandedElts,
                             APInt &UndefElts, unsigned Depth = 0) const;
 
  /// Test whether \p V has a splatted value.
  LLVM_ABI bool isSplatValue(SDValue V, bool AllowUndefs = false) const;
 
  /// If V is a splatted value, return the source vector and its splat index.
  LLVM_ABI SDValue getSplatSourceVector(SDValue V, int &SplatIndex);
 
  /// If V is a splat vector, return its scalar source operand by extracting
  /// that element from the source vector. If LegalTypes is true, this method
  /// may only return a legally-typed splat value. If it cannot legalize the
  /// splatted value it will return SDValue().
  LLVM_ABI SDValue getSplatValue(SDValue V, bool LegalTypes = false);
 
  /// If a SHL/SRA/SRL node \p V has shift amounts that are all less than the
  /// element bit-width of the shift node, return the valid constant range.
  LLVM_ABI std::optional<ConstantRange>
  getValidShiftAmountRange(SDValue V, const APInt &DemandedElts,
                           unsigned Depth) const;
 
  /// If a SHL/SRA/SRL node \p V has a uniform shift amount
  /// that is less than the element bit-width of the shift node, return it.
  LLVM_ABI std::optional<unsigned>
  getValidShiftAmount(SDValue V, const APInt &DemandedElts,
                      unsigned Depth = 0) const;
 
  /// If a SHL/SRA/SRL node \p V has a uniform shift amount
  /// that is less than the element bit-width of the shift node, return it.
  LLVM_ABI std::optional<unsigned>
  getValidShiftAmount(SDValue V, unsigned Depth = 0) const;
 
  /// If a SHL/SRA/SRL node \p V has shift amounts that are all less than the
  /// element bit-width of the shift node, return the minimum possible value.
  LLVM_ABI std::optional<unsigned>
  getValidMinimumShiftAmount(SDValue V, const APInt &DemandedElts,
                             unsigned Depth = 0) const;
 
  /// If a SHL/SRA/SRL node \p V has shift amounts that are all less than the
  /// element bit-width of the shift node, return the minimum possible value.
  LLVM_ABI std::optional<unsigned>
  getValidMinimumShiftAmount(SDValue V, unsigned Depth = 0) const;
 
  /// If a SHL/SRA/SRL node \p V has shift amounts that are all less than the
  /// element bit-width of the shift node, return the maximum possible value.
  LLVM_ABI std::optional<unsigned>
  getValidMaximumShiftAmount(SDValue V, const APInt &DemandedElts,
                             unsigned Depth = 0) const;
 
  /// If a SHL/SRA/SRL node \p V has shift amounts that are all less than the
  /// element bit-width of the shift node, return the maximum possible value.
  LLVM_ABI std::optional<unsigned>
  getValidMaximumShiftAmount(SDValue V, unsigned Depth = 0) const;
 
  /// Match a binop + shuffle pyramid that represents a horizontal reduction
  /// over the elements of a vector starting from the EXTRACT_VECTOR_ELT node /p
  /// Extract. The reduction must use one of the opcodes listed in /p
  /// CandidateBinOps and on success /p BinOp will contain the matching opcode.
  /// Returns the vector that is being reduced on, or SDValue() if a reduction
  /// was not matched. If \p AllowPartials is set then in the case of a
  /// reduction pattern that only matches the first few stages, the extracted
  /// subvector of the start of the reduction is returned.
  LLVM_ABI SDValue matchBinOpReduction(SDNode *Extract, ISD::NodeType &BinOp,
                                       ArrayRef<ISD::NodeType> CandidateBinOps,
                                       bool AllowPartials = false);
 
  /// Utility function used by legalize and lowering to
  /// "unroll" a vector operation by splitting out the scalars and operating
  /// on each element individually.  If the ResNE is 0, fully unroll the vector
  /// op. If ResNE is less than the width of the vector op, unroll up to ResNE.
  /// If the  ResNE is greater than the width of the vector op, unroll the
  /// vector op and fill the end of the resulting vector with UNDEFS.
  LLVM_ABI SDValue UnrollVectorOp(SDNode *N, unsigned ResNE = 0);
 
  /// Like UnrollVectorOp(), but for the [US](ADD|SUB|MUL)O family of opcodes.
  /// This is a separate function because those opcodes have two results.
  LLVM_ABI std::pair<SDValue, SDValue>
  UnrollVectorOverflowOp(SDNode *N, unsigned ResNE = 0);
 
  /// Return true if loads are next to each other and can be
  /// merged. Check that both are nonvolatile and if LD is loading
  /// 'Bytes' bytes from a location that is 'Dist' units away from the
  /// location that the 'Base' load is loading from.
  LLVM_ABI bool areNonVolatileConsecutiveLoads(LoadSDNode *LD, LoadSDNode *Base,
                                               unsigned Bytes, int Dist) const;
 
  /// Return true if stores are next to each other and can be merged. Check that
  /// both are nonvolatile and if \p ST is storing \p Bytes bytes to a location
  /// that is \p Dist units away from the location that \p Base is storing to.
  LLVM_ABI bool areNonVolatileConsecutiveStores(StoreSDNode *ST,
                                                StoreSDNode *Base,
                                                unsigned Bytes, int Dist) const;
 
  /// Infer alignment of a load / store address. Return std::nullopt if it
  /// cannot be inferred.
  LLVM_ABI MaybeAlign InferPtrAlign(SDValue Ptr) const;
 
  /// Split the scalar node with EXTRACT_ELEMENT using the provided VTs and
  /// return the low/high part.
  LLVM_ABI std::pair<SDValue, SDValue> SplitScalar(const SDValue &N,
                                                   const SDLoc &DL,
                                                   const EVT &LoVT,
                                                   const EVT &HiVT);
 
  /// Compute the VTs needed for the low/hi parts of a type
  /// which is split (or expanded) into two not necessarily identical pieces.
  LLVM_ABI std::pair<EVT, EVT> GetSplitDestVTs(const EVT &VT) const;
 
  /// Compute the VTs needed for the low/hi parts of a type, dependent on an
  /// enveloping VT that has been split into two identical pieces. Sets the
  /// HisIsEmpty flag when hi type has zero storage size.
  LLVM_ABI std::pair<EVT, EVT> GetDependentSplitDestVTs(const EVT &VT,
                                                        const EVT &EnvVT,
                                                        bool *HiIsEmpty) const;
 
  /// Split the vector with EXTRACT_SUBVECTOR using the provided
  /// VTs and return the low/high part.
  LLVM_ABI std::pair<SDValue, SDValue> SplitVector(const SDValue &N,
                                                   const SDLoc &DL,
                                                   const EVT &LoVT,
                                                   const EVT &HiVT);
 
  /// Split the vector with EXTRACT_SUBVECTOR and return the low/high part.
  std::pair<SDValue, SDValue> SplitVector(const SDValue &N, const SDLoc &DL) {
    EVT LoVT, HiVT;
    std::tie(LoVT, HiVT) = GetSplitDestVTs(N.getValueType());
    return SplitVector(N, DL, LoVT, HiVT);
  }
 
  /// Split the explicit vector length parameter of a VP operation.
  LLVM_ABI std::pair<SDValue, SDValue> SplitEVL(SDValue N, EVT VecVT,
                                                const SDLoc &DL);
 
  /// Split the node's operand with EXTRACT_SUBVECTOR and
  /// return the low/high part.
  std::pair<SDValue, SDValue> SplitVectorOperand(const SDNode *N, unsigned OpNo)
  {
    return SplitVector(N->getOperand(OpNo), SDLoc(N));
  }
 
  /// Widen the vector up to the next power of two using INSERT_SUBVECTOR.
  LLVM_ABI SDValue WidenVector(const SDValue &N, const SDLoc &DL);
 
  /// Append the extracted elements from Start to Count out of the vector Op in
  /// Args. If Count is 0, all of the elements will be extracted. The extracted
  /// elements will have type EVT if it is provided, and otherwise their type
  /// will be Op's element type.
  LLVM_ABI void ExtractVectorElements(SDValue Op,
                                      SmallVectorImpl<SDValue> &Args,
                                      unsigned Start = 0, unsigned Count = 0,
                                      EVT EltVT = EVT());
 
  /// Compute the default alignment value for the given type.
  LLVM_ABI Align getEVTAlign(EVT MemoryVT) const;
 
  /// Test whether the given value is a constant int or similar node.
  LLVM_ABI bool
  isConstantIntBuildVectorOrConstantInt(SDValue N,
                                        bool AllowOpaques = true) const;
 
  /// Test whether the given value is a constant FP or similar node.
  LLVM_ABI bool isConstantFPBuildVectorOrConstantFP(SDValue N) const;
 
  /// \returns true if \p N is any kind of constant or build_vector of
  /// constants, int or float. If a vector, it may not necessarily be a splat.
  inline bool isConstantValueOfAnyType(SDValue N) const {
    return isConstantIntBuildVectorOrConstantInt(N) ||
           isConstantFPBuildVectorOrConstantFP(N);
  }
 
  /// Check if a value \op N is a constant using the target's BooleanContent for
  /// its type.
  LLVM_ABI std::optional<bool> isBoolConstant(SDValue N) const;
 
  /// Set CallSiteInfo to be associated with Node.
  void addCallSiteInfo(const SDNode *Node, CallSiteInfo &&CallInfo) {
    SDEI[Node].CSInfo = std::move(CallInfo);
  }
  /// Return CallSiteInfo associated with Node, or a default if none exists.
  CallSiteInfo getCallSiteInfo(const SDNode *Node) {
    auto I = SDEI.find(Node);
    return I != SDEI.end() ? std::move(I->second).CSInfo : CallSiteInfo();
  }
  /// Set HeapAllocSite to be associated with Node.
  void addHeapAllocSite(const SDNode *Node, MDNode *MD) {
    SDEI[Node].HeapAllocSite = MD;
  }
  /// Return HeapAllocSite associated with Node, or nullptr if none exists.
  MDNode *getHeapAllocSite(const SDNode *Node) const {
    auto I = SDEI.find(Node);
    return I != SDEI.end() ? I->second.HeapAllocSite : nullptr;
  }
  /// Set PCSections to be associated with Node.
  void addPCSections(const SDNode *Node, MDNode *MD) {
    SDEI[Node].PCSections = MD;
  }
  /// Set MMRAMetadata to be associated with Node.
  void addMMRAMetadata(const SDNode *Node, MDNode *MMRA) {
    SDEI[Node].MMRA = MMRA;
  }
  /// Return PCSections associated with Node, or nullptr if none exists.
  MDNode *getPCSections(const SDNode *Node) const {
    auto It = SDEI.find(Node);
    return It != SDEI.end() ? It->second.PCSections : nullptr;
  }
  /// Return the MMRA MDNode associated with Node, or nullptr if none
  /// exists.
  MDNode *getMMRAMetadata(const SDNode *Node) const {
    auto It = SDEI.find(Node);
    return It != SDEI.end() ? It->second.MMRA : nullptr;
  }
  /// Set CalledGlobal to be associated with Node.
  void addCalledGlobal(const SDNode *Node, const GlobalValue *GV,
                       unsigned OpFlags) {
    SDEI[Node].CalledGlobal = {GV, OpFlags};
  }
  /// Return CalledGlobal associated with Node, or a nullopt if none exists.
  std::optional<CalledGlobalInfo> getCalledGlobal(const SDNode *Node) {
    auto I = SDEI.find(Node);
    return I != SDEI.end()
               ? std::make_optional(std::move(I->second).CalledGlobal)
               : std::nullopt;
  }
  /// Set NoMergeSiteInfo to be associated with Node if NoMerge is true.
  void addNoMergeSiteInfo(const SDNode *Node, bool NoMerge) {
    if (NoMerge)
      SDEI[Node].NoMerge = NoMerge;
  }
  /// Return NoMerge info associated with Node.
  bool getNoMergeSiteInfo(const SDNode *Node) const {
    auto I = SDEI.find(Node);
    return I != SDEI.end() ? I->second.NoMerge : false;
  }
 
  /// Copy extra info associated with one node to another.
  LLVM_ABI void copyExtraInfo(SDNode *From, SDNode *To);
 
  /// Return the current function's default denormal handling kind for the given
  /// floating point type.
  DenormalMode getDenormalMode(EVT VT) const {
    return MF->getDenormalMode(VT.getFltSemantics());
  }
 
  LLVM_ABI bool shouldOptForSize() const;
 
  /// Get the (commutative) identity element for the given opcode, if it exists.
  LLVM_ABI SDValue getIdentityElement(unsigned Opcode, const SDLoc &DL, EVT VT,
                                      SDNodeFlags Flags);
 
  /// Get an expression that implements a partial multiply-subtract reduction.
  /// In practice this means that parts of the expression are negated, e.g.
  ///
  ///     partial_reduce_fmls acc, lhs, rhs
  /// <=> partial_reduce_fmla acc, lhs, -rhs
  ///
  ///      partial_reduce_umls acc, lhs, rhs
  /// <=> -partial_reduce_umla -acc, lhs, rhs
  LLVM_ABI SDValue getPartialReduceMLS(unsigned Opc, const SDLoc &DL,
                                       SDValue Acc, SDValue LHS, SDValue RHS);
 
  /// Some opcodes may create immediate undefined behavior when used with some
  /// values (integer division-by-zero for example). Therefore, these operations
  /// are not generally safe to move around or change.
  bool isSafeToSpeculativelyExecute(unsigned Opcode) const {
    switch (Opcode) {
    case ISD::SDIV:
    case ISD::SREM:
    case ISD::SDIVREM:
    case ISD::UDIV:
    case ISD::UREM:
    case ISD::UDIVREM:
      return false;
    default:
      return true;
    }
  }
 
  /// Check if the provided node is save to speculatively executed given its
  /// current arguments. So, while `udiv` the opcode is not safe to
  /// speculatively execute, a given `udiv` node may be if the denominator is
  /// known nonzero.
  bool isSafeToSpeculativelyExecuteNode(const SDNode *N) const {
    switch (N->getOpcode()) {
    case ISD::UDIV:
      return isKnownNeverZero(N->getOperand(1));
    default:
      return isSafeToSpeculativelyExecute(N->getOpcode());
    }
  }
 
  LLVM_ABI SDValue makeStateFunctionCall(unsigned LibFunc, SDValue Ptr,
                                         SDValue InChain, const SDLoc &DLoc);
 
  /// Returns the maximum runtime number of elements in VT if known, or 0
  /// otherwise.
  unsigned getMaxRuntimeNumElements(EVT VT) const;
 
  /// Returns a vector constructed from the scalar values in order. The number
  /// of scalars must match the maximum runtime length of VT, but only the first
  /// actual runtime length scalars are included in the result.
  SDValue buildVectorFromUnrolledParts(EVT VT, const SDLoc &DL,
                                       ArrayRef<SDValue> Scalars);
 
private:
#ifndef NDEBUG
  void verifyNode(SDNode *N) const;
#endif
  void InsertNode(SDNode *N);
  bool RemoveNodeFromCSEMaps(SDNode *N);
  void AddModifiedNodeToCSEMaps(SDNode *N);
  SDNode *FindModifiedNodeSlot(SDNode *N, SDValue Op,
                               FoldingSetInsertToken &InsertToken);
  SDNode *FindModifiedNodeSlot(SDNode *N, SDValue Op1, SDValue Op2,
                               FoldingSetInsertToken &InsertToken);
  SDNode *FindModifiedNodeSlot(SDNode *N, ArrayRef<SDValue> Ops,
                               FoldingSetInsertToken &InsertToken);
  SDNode *UpdateSDLocOnMergeSDNode(SDNode *N, const SDLoc &loc);
 
  void DeleteNodeNotInCSEMaps(SDNode *N);
  void DeallocateNode(SDNode *N);
 
  void allnodes_clear();
 
  /// Look up the node specified by ID in CSEMap. If it exists, return it and
  /// clear \p InsertToken; otherwise return null and set \p InsertToken for a
  /// subsequent insert. This overload is for nodes other than Constant or
  /// ConstantFP, use the other one for those.
  SDNode *lookupNode(const SDNodeKey &Key, FoldingSetInsertToken &InsertToken);
 
  /// Look up the node specified by ID in CSEMap. If it exists, return it and
  /// clear \p InsertToken; otherwise return null and set \p InsertToken for a
  /// subsequent insert. Performs additional processing for constant nodes.
  SDNode *lookupNode(const SDNodeKey &Key, const SDLoc &DL,
                     FoldingSetInsertToken &InsertToken);
 
  /// Maps to auto-CSE operations.
  std::vector<CondCodeSDNode*> CondCodeNodes;
 
  std::vector<SDNode*> ValueTypeNodes;
  std::map<EVT, SDNode*, EVT::compareRawBits> ExtendedValueTypeNodes;
  StringMap<SDNode*> ExternalSymbols;
 
  std::map<std::pair<std::string, unsigned>, SDNode *> TargetExternalSymbols;
  DenseMap<MCSymbol *, SDNode *> MCSymbols;
 
  FlagInserter *Inserter = nullptr;
};
 
template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> {
  using nodes_iterator = pointer_iterator<SelectionDAG::allnodes_iterator>;
 
  static nodes_iterator nodes_begin(SelectionDAG *G) {
    return nodes_iterator(G->allnodes_begin());
  }
 
  static nodes_iterator nodes_end(SelectionDAG *G) {
    return nodes_iterator(G->allnodes_end());
  }
};
 
} // end namespace llvm
 
#endif // LLVM_CODEGEN_SELECTIONDAG_H