//===- llvm/CodeGen/GlobalISel/LegalizerInfo.h ------------------*- C++ -*-===//

//

//                     The LLVM Compiler Infrastructure

//

// This file is distributed under the University of Illinois Open Source

// License. See LICENSE.TXT for details.

//

//===----------------------------------------------------------------------===//

//

/// Interface for Targets to specify which operations they can successfully

/// select and how the others should be expanded most efficiently.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_CODEGEN_GLOBALISEL_LEGALIZERINFO_H

#define LLVM_CODEGEN_GLOBALISEL_LEGALIZERINFO_H

#include "llvm/ADT/DenseMap.h"

#include "llvm/ADT/None.h"

#include "llvm/ADT/Optional.h"

#include "llvm/ADT/STLExtras.h"

#include "llvm/ADT/SmallBitVector.h"

#include "llvm/ADT/SmallVector.h"

#include "llvm/CodeGen/MachineFunction.h"

#include "llvm/CodeGen/TargetOpcodes.h"

#include "llvm/Support/raw_ostream.h"

#include "llvm/Support/LowLevelTypeImpl.h"

#include <cassert>

#include <cstdint>

#include <tuple>

#include <unordered_map>

#include <utility>

namespace llvm {

extern cl::opt<bool> DisableGISelLegalityCheck;

class MachineInstr;

class MachineIRBuilder;

class MachineRegisterInfo;

class MCInstrInfo;

namespace LegalizeActions {

enum LegalizeAction : std::uint8_t {

  /// The operation is expected to be selectable directly by the target, and

  /// no transformation is necessary.

  Legal,

  /// The operation should be synthesized from multiple instructions acting on

  /// a narrower scalar base-type. For example a 64-bit add might be

  /// implemented in terms of 32-bit add-with-carry.

  NarrowScalar,

  /// The operation should be implemented in terms of a wider scalar

  /// base-type. For example a <2 x s8> add could be implemented as a <2

  /// x s32> add (ignoring the high bits).

  WidenScalar,

  /// The (vector) operation should be implemented by splitting it into

  /// sub-vectors where the operation is legal. For example a <8 x s64> add

  /// might be implemented as 4 separate <2 x s64> adds.

  FewerElements,

  /// The (vector) operation should be implemented by widening the input

  /// vector and ignoring the lanes added by doing so. For example <2 x i8> is

  /// rarely legal, but you might perform an <8 x i8> and then only look at

  /// the first two results.

  MoreElements,

  /// The operation itself must be expressed in terms of simpler actions on

  /// this target. E.g. a SREM replaced by an SDIV and subtraction.

  Lower,

  /// The operation should be implemented as a call to some kind of runtime

  /// support library. For example this usually happens on machines that don't

  /// support floating-point operations natively.

  Libcall,

  /// The target wants to do something special with this combination of

  /// operand and type. A callback will be issued when it is needed.

  Custom,

  /// This operation is completely unsupported on the target. A programming

  /// error has occurred.

  Unsupported,

  /// Sentinel value for when no action was found in the specified table.

  NotFound,

  /// Fall back onto the old rules.

  /// TODO: Remove this once we've migrated

  UseLegacyRules,

};

} // end namespace LegalizeActions

using LegalizeActions::LegalizeAction;

/// Legalization is decided based on an instruction's opcode, which type slot

/// we're considering, and what the existing type is. These aspects are gathered

/// together for convenience in the InstrAspect class.

struct InstrAspect {

  unsigned Opcode;

  unsigned Idx = 0;

  LLT Type;

  InstrAspect(unsigned Opcode, LLT Type) : Opcode(Opcode), Type(Type) {}

  InstrAspect(unsigned Opcode, unsigned Idx, LLT Type)

      : Opcode(Opcode), Idx(Idx), Type(Type) {}

  bool operator==(const InstrAspect &RHS) const {

    return Opcode == RHS.Opcode && Idx == RHS.Idx && Type == RHS.Type;

  }

};

/// The LegalityQuery object bundles together all the information that's needed

/// to decide whether a given operation is legal or not.

/// For efficiency, it doesn't make a copy of Types so care must be taken not

/// to free it before using the query.

struct LegalityQuery {

  unsigned Opcode;

  ArrayRef<LLT> Types;

  struct MemDesc {

    uint64_t Size;

    AtomicOrdering Ordering;

  };

  /// Operations which require memory can use this to place requirements on the

  /// memory type for each MMO.

  ArrayRef<MemDesc> MMODescrs;

  constexpr LegalityQuery(unsigned Opcode, const ArrayRef<LLT> Types,

                          const ArrayRef<MemDesc> MMODescrs)

      : Opcode(Opcode), Types(Types), MMODescrs(MMODescrs) {}

  constexpr LegalityQuery(unsigned Opcode, const ArrayRef<LLT> Types)

      : LegalityQuery(Opcode, Types, {}) {}

  raw_ostream &print(raw_ostream &OS) const;

};

/// The result of a query. It either indicates a final answer of Legal or

/// Unsupported or describes an action that must be taken to make an operation

/// more legal.

struct LegalizeActionStep {

  /// The action to take or the final answer.

  LegalizeAction Action;

  /// If describing an action, the type index to change. Otherwise zero.

  unsigned TypeIdx;

  /// If describing an action, the new type for TypeIdx. Otherwise LLT{}.

  LLT NewType;

  LegalizeActionStep(LegalizeAction Action, unsigned TypeIdx,

                     const LLT &NewType)

      : Action(Action), TypeIdx(TypeIdx), NewType(NewType) {}

  bool operator==(const LegalizeActionStep &RHS) const {

    return std::tie(Action, TypeIdx, NewType) ==

        std::tie(RHS.Action, RHS.TypeIdx, RHS.NewType);

  }

};

using LegalityPredicate = std::function<bool (const LegalityQuery &)>;

using LegalizeMutation =

    std::function<std::pair<unsigned, LLT>(const LegalityQuery &)>;

namespace LegalityPredicates {

struct TypePairAndMemSize {

  LLT Type0;

  LLT Type1;

  uint64_t MemSize;

  bool operator==(const TypePairAndMemSize &Other) const {

    return Type0 == Other.Type0 && 
Type1 == Other.Type11.55M
 &&

           
MemSize == Other.MemSize1.55M
;

  }

};

/// True iff P0 and P1 are true.

template<typename Predicate>

Predicate all(Predicate P0, Predicate P1) {

  return [=](const LegalityQuery &Query) {

    return P0(Query) && 
P1(Query)431k
;

  };

}

/// True iff all given predicates are true.

template<typename Predicate, typename... Args>

Predicate all(Predicate P0, Predicate P1, Args... args) {

  return all(all(P0, P1), args...);

}

std::__1::function<bool (llvm::LegalityQuery const&)> llvm::LegalityPredicates::all<std::__1::function<bool (llvm::LegalityQuery const&)>, std::__1::function<bool (llvm::LegalityQuery const&)>, std::__1::function<bool (llvm::LegalityQuery const&)> >(std::__1::function<bool (llvm::LegalityQuery const&)>, std::__1::function<bool (llvm::LegalityQuery const&)>, std::__1::function<bool (llvm::LegalityQuery const&)>, std::__1::function<bool (llvm::LegalityQuery const&)>)

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31

Predicate all(Predicate P0, Predicate P1, Args... args) {

188

31

  return all(all(P0, P1), args...);

189

31

}

std::__1::function<bool (llvm::LegalityQuery const&)> llvm::LegalityPredicates::all<std::__1::function<bool (llvm::LegalityQuery const&)>, std::__1::function<bool (llvm::LegalityQuery const&)> >(std::__1::function<bool (llvm::LegalityQuery const&)>, std::__1::function<bool (llvm::LegalityQuery const&)>, std::__1::function<bool (llvm::LegalityQuery const&)>)

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Source

187

62

Predicate all(Predicate P0, Predicate P1, Args... args) {

188

62

  return all(all(P0, P1), args...);

189

62

}

/// True iff the given type index is the specified types.

LegalityPredicate typeIs(unsigned TypeIdx, LLT TypesInit);

/// True iff the given type index is one of the specified types.

LegalityPredicate typeInSet(unsigned TypeIdx,

                            std::initializer_list<LLT> TypesInit);

/// True iff the given types for the given pair of type indexes is one of the

/// specified type pairs.

LegalityPredicate

typePairInSet(unsigned TypeIdx0, unsigned TypeIdx1,

              std::initializer_list<std::pair<LLT, LLT>> TypesInit);

/// True iff the given types for the given pair of type indexes is one of the

/// specified type pairs.

LegalityPredicate typePairAndMemSizeInSet(

    unsigned TypeIdx0, unsigned TypeIdx1, unsigned MMOIdx,

    std::initializer_list<TypePairAndMemSize> TypesAndMemSizeInit);

/// True iff the specified type index is a scalar.

LegalityPredicate isScalar(unsigned TypeIdx);

/// True iff the specified type index is a scalar that's narrower than the given

/// size.

LegalityPredicate narrowerThan(unsigned TypeIdx, unsigned Size);

/// True iff the specified type index is a scalar that's wider than the given

/// size.

LegalityPredicate widerThan(unsigned TypeIdx, unsigned Size);

/// True iff the specified type index is a scalar whose size is not a power of

/// 2.

LegalityPredicate sizeNotPow2(unsigned TypeIdx);

/// True iff the specified MMO index has a size that is not a power of 2

LegalityPredicate memSizeInBytesNotPow2(unsigned MMOIdx);

/// True iff the specified type index is a vector whose element count is not a

/// power of 2.

LegalityPredicate numElementsNotPow2(unsigned TypeIdx);

/// True iff the specified MMO index has at an atomic ordering of at Ordering or

/// stronger.

LegalityPredicate atomicOrderingAtLeastOrStrongerThan(unsigned MMOIdx,

                                                      AtomicOrdering Ordering);

} // end namespace LegalityPredicates

namespace LegalizeMutations {

/// Select this specific type for the given type index.

LegalizeMutation changeTo(unsigned TypeIdx, LLT Ty);

/// Keep the same type as the given type index.

LegalizeMutation changeTo(unsigned TypeIdx, unsigned FromTypeIdx);

/// Widen the type for the given type index to the next power of 2.

LegalizeMutation widenScalarToNextPow2(unsigned TypeIdx, unsigned Min = 0);

/// Add more elements to the type for the given type index to the next power of

/// 2.

LegalizeMutation moreElementsToNextPow2(unsigned TypeIdx, unsigned Min = 0);

} // end namespace LegalizeMutations

/// A single rule in a legalizer info ruleset.

/// The specified action is chosen when the predicate is true. Where appropriate

/// for the action (e.g. for WidenScalar) the new type is selected using the

/// given mutator.

class LegalizeRule {

  LegalityPredicate Predicate;

  LegalizeAction Action;

  LegalizeMutation Mutation;

public:

  LegalizeRule(LegalityPredicate Predicate, LegalizeAction Action,

               LegalizeMutation Mutation = nullptr)

      : Predicate(Predicate), Action(Action), Mutation(Mutation) {}

  /// Test whether the LegalityQuery matches.

  bool match(const LegalityQuery &Query) const {

    return Predicate(Query);

  }

  LegalizeAction getAction() const { return Action; }

  /// Determine the change to make.

  std::pair<unsigned, LLT> determineMutation(const LegalityQuery &Query) const {

    if (Mutation)

      return Mutation(Query);

    return std::make_pair(0, LLT{});

  }

};

class LegalizeRuleSet {

  /// When non-zero, the opcode we are an alias of

  unsigned AliasOf;

  /// If true, there is another opcode that aliases this one

  bool IsAliasedByAnother;

  SmallVector<LegalizeRule, 2> Rules;

#ifndef NDEBUG

  /// If bit I is set, this rule set contains a rule that may handle (predicate

  /// or perform an action upon (or both)) the type index I. The uncertainty

  /// comes from free-form rules executing user-provided lambda functions. We

  /// conservatively assume such rules do the right thing and cover all type

  /// indices. The bitset is intentionally 1 bit wider than it absolutely needs

  /// to be to distinguish such cases from the cases where all type indices are

  /// individually handled.

  SmallBitVector TypeIdxsCovered{MCOI::OPERAND_LAST_GENERIC -

                                 MCOI::OPERAND_FIRST_GENERIC + 2};

#endif

  unsigned typeIdx(unsigned TypeIdx) {

    assert(TypeIdx <=

               (MCOI::OPERAND_LAST_GENERIC - MCOI::OPERAND_FIRST_GENERIC) &&

           "Type Index is out of bounds");

#ifndef NDEBUG

    TypeIdxsCovered.set(TypeIdx);

#endif

    return TypeIdx;

  }

  void markAllTypeIdxsAsCovered() {

#ifndef NDEBUG

    TypeIdxsCovered.set();

#endif

  }

  void add(const LegalizeRule &Rule) {

    assert(AliasOf == 0 &&

           "RuleSet is aliased, change the representative opcode instead");

    Rules.push_back(Rule);

  }

  static bool always(const LegalityQuery &) { return true; }

  /// Use the given action when the predicate is true.

  /// Action should not be an action that requires mutation.

  LegalizeRuleSet &actionIf(LegalizeAction Action,

                            LegalityPredicate Predicate) {

    add({Predicate, Action});

    return *this;

  }

  /// Use the given action when the predicate is true.

  /// Action should be an action that requires mutation.

  LegalizeRuleSet &actionIf(LegalizeAction Action, LegalityPredicate Predicate,

                            LegalizeMutation Mutation) {

    add({Predicate, Action, Mutation});

    return *this;

  }

  /// Use the given action when type index 0 is any type in the given list.

  /// Action should not be an action that requires mutation.

  LegalizeRuleSet &actionFor(LegalizeAction Action,

                             std::initializer_list<LLT> Types) {

    using namespace LegalityPredicates;

    return actionIf(Action, typeInSet(typeIdx(0), Types));

  }

  /// Use the given action when type index 0 is any type in the given list.

  /// Action should be an action that requires mutation.

  LegalizeRuleSet &actionFor(LegalizeAction Action,

                             std::initializer_list<LLT> Types,

                             LegalizeMutation Mutation) {

    using namespace LegalityPredicates;

    return actionIf(Action, typeInSet(typeIdx(0), Types), Mutation);

  }

  /// Use the given action when type indexes 0 and 1 is any type pair in the

  /// given list.

  /// Action should not be an action that requires mutation.

  LegalizeRuleSet &actionFor(LegalizeAction Action,

                             std::initializer_list<std::pair<LLT, LLT>> Types) {

    using namespace LegalityPredicates;

    return actionIf(Action, typePairInSet(typeIdx(0), typeIdx(1), Types));

  }

  /// Use the given action when type indexes 0 and 1 is any type pair in the

  /// given list.

  /// Action should be an action that requires mutation.

  LegalizeRuleSet &actionFor(LegalizeAction Action,

                             std::initializer_list<std::pair<LLT, LLT>> Types,

                             LegalizeMutation Mutation) {

    using namespace LegalityPredicates;

    return actionIf(Action, typePairInSet(typeIdx(0), typeIdx(1), Types),

                    Mutation);

  }

  /// Use the given action when type indexes 0 and 1 are both in the given list.

  /// That is, the type pair is in the cartesian product of the list.

  /// Action should not be an action that requires mutation.

  LegalizeRuleSet &actionForCartesianProduct(LegalizeAction Action,

                                             std::initializer_list<LLT> Types) {

    using namespace LegalityPredicates;

    return actionIf(Action, all(typeInSet(typeIdx(0), Types),

                                typeInSet(typeIdx(1), Types)));

  }

  /// Use the given action when type indexes 0 and 1 are both in their

  /// respective lists.

  /// That is, the type pair is in the cartesian product of the lists

  /// Action should not be an action that requires mutation.

  LegalizeRuleSet &

  actionForCartesianProduct(LegalizeAction Action,

                            std::initializer_list<LLT> Types0,

                            std::initializer_list<LLT> Types1) {

    using namespace LegalityPredicates;

    return actionIf(Action, all(typeInSet(typeIdx(0), Types0),

                                typeInSet(typeIdx(1), Types1)));

  }

  /// Use the given action when type indexes 0, 1, and 2 are all in their

  /// respective lists.

  /// That is, the type triple is in the cartesian product of the lists

  /// Action should not be an action that requires mutation.

  LegalizeRuleSet &actionForCartesianProduct(

      LegalizeAction Action, std::initializer_list<LLT> Types0,

      std::initializer_list<LLT> Types1, std::initializer_list<LLT> Types2) {

    using namespace LegalityPredicates;

    return actionIf(Action, all(typeInSet(typeIdx(0), Types0),

                                all(typeInSet(typeIdx(1), Types1),

                                    typeInSet(typeIdx(2), Types2))));

  }

public:

  LegalizeRuleSet() : AliasOf(0), IsAliasedByAnother(false), Rules() {}

  bool isAliasedByAnother() { return IsAliasedByAnother; }

  void setIsAliasedByAnother() { IsAliasedByAnother = true; }

  void aliasTo(unsigned Opcode) {

    assert((AliasOf == 0 || AliasOf == Opcode) &&

           "Opcode is already aliased to another opcode");

    assert(Rules.empty() && "Aliasing will discard rules");

    AliasOf = Opcode;

  }

  unsigned getAlias() const { return AliasOf; }

  /// The instruction is legal if predicate is true.

  LegalizeRuleSet &legalIf(LegalityPredicate Predicate) {

    // We have no choice but conservatively assume that the free-form

    // user-provided Predicate properly handles all type indices:

    markAllTypeIdxsAsCovered();

    return actionIf(LegalizeAction::Legal, Predicate);

  }

  /// The instruction is legal when type index 0 is any type in the given list.

  LegalizeRuleSet &legalFor(std::initializer_list<LLT> Types) {

    return actionFor(LegalizeAction::Legal, Types);

  }

  /// The instruction is legal when type indexes 0 and 1 is any type pair in the

  /// given list.

  LegalizeRuleSet &legalFor(std::initializer_list<std::pair<LLT, LLT>> Types) {

    return actionFor(LegalizeAction::Legal, Types);

  }

  /// The instruction is legal when type indexes 0 and 1 along with the memory

  /// size is any type and size tuple in the given list.

  LegalizeRuleSet &legalForTypesWithMemSize(

      std::initializer_list<LegalityPredicates::TypePairAndMemSize>

          TypesAndMemSize) {

    return actionIf(LegalizeAction::Legal,

                    LegalityPredicates::typePairAndMemSizeInSet(

                        typeIdx(0), typeIdx(1), /*MMOIdx*/ 0, TypesAndMemSize));

  }

  /// The instruction is legal when type indexes 0 and 1 are both in the given

  /// list. That is, the type pair is in the cartesian product of the list.

  LegalizeRuleSet &legalForCartesianProduct(std::initializer_list<LLT> Types) {

    return actionForCartesianProduct(LegalizeAction::Legal, Types);

  }

  /// The instruction is legal when type indexes 0 and 1 are both their

  /// respective lists.

  LegalizeRuleSet &legalForCartesianProduct(std::initializer_list<LLT> Types0,

                                            std::initializer_list<LLT> Types1) {

    return actionForCartesianProduct(LegalizeAction::Legal, Types0, Types1);

  }

  /// The instruction is lowered.

  LegalizeRuleSet &lower() {

    using namespace LegalizeMutations;

    // We have no choice but conservatively assume that predicate-less lowering

    // properly handles all type indices by design:

    markAllTypeIdxsAsCovered();

    return actionIf(LegalizeAction::Lower, always);

  }

  /// The instruction is lowered if predicate is true. Keep type index 0 as the

  /// same type.

  LegalizeRuleSet &lowerIf(LegalityPredicate Predicate) {

    using namespace LegalizeMutations;

    // We have no choice but conservatively assume that lowering with a

    // free-form user provided Predicate properly handles all type indices:

    markAllTypeIdxsAsCovered();

    return actionIf(LegalizeAction::Lower, Predicate);

  }

  /// The instruction is lowered if predicate is true.

  LegalizeRuleSet &lowerIf(LegalityPredicate Predicate,

                           LegalizeMutation Mutation) {

    // We have no choice but conservatively assume that lowering with a

    // free-form user provided Predicate properly handles all type indices:

    markAllTypeIdxsAsCovered();

    return actionIf(LegalizeAction::Lower, Predicate, Mutation);

  }

  /// The instruction is lowered when type index 0 is any type in the given

  /// list. Keep type index 0 as the same type.

  LegalizeRuleSet &lowerFor(std::initializer_list<LLT> Types) {

    return actionFor(LegalizeAction::Lower, Types,

                     LegalizeMutations::changeTo(0, 0));

  }

  /// The instruction is lowered when type index 0 is any type in the given

  /// list.

  LegalizeRuleSet &lowerFor(std::initializer_list<LLT> Types,

                            LegalizeMutation Mutation) {

    return actionFor(LegalizeAction::Lower, Types, Mutation);

  }

  /// The instruction is lowered when type indexes 0 and 1 is any type pair in

  /// the given list. Keep type index 0 as the same type.

  LegalizeRuleSet &lowerFor(std::initializer_list<std::pair<LLT, LLT>> Types) {

    return actionFor(LegalizeAction::Lower, Types,

                     LegalizeMutations::changeTo(0, 0));

  }

  /// The instruction is lowered when type indexes 0 and 1 is any type pair in

  /// the given list.

  LegalizeRuleSet &lowerFor(std::initializer_list<std::pair<LLT, LLT>> Types,

                            LegalizeMutation Mutation) {

    return actionFor(LegalizeAction::Lower, Types, Mutation);

  }

  /// The instruction is lowered when type indexes 0 and 1 are both in their

  /// respective lists.

  LegalizeRuleSet &lowerForCartesianProduct(std::initializer_list<LLT> Types0,

                                            std::initializer_list<LLT> Types1) {

    using namespace LegalityPredicates;

    return actionForCartesianProduct(LegalizeAction::Lower, Types0, Types1);

  }

  /// The instruction is lowered when when type indexes 0, 1, and 2 are all in

  /// their respective lists.

  LegalizeRuleSet &lowerForCartesianProduct(std::initializer_list<LLT> Types0,

                                            std::initializer_list<LLT> Types1,

                                            std::initializer_list<LLT> Types2) {

    using namespace LegalityPredicates;

    return actionForCartesianProduct(LegalizeAction::Lower, Types0, Types1,

                                     Types2);

  }

  /// Like legalIf, but for the Libcall action.

  LegalizeRuleSet &libcallIf(LegalityPredicate Predicate) {

    // We have no choice but conservatively assume that a libcall with a

    // free-form user provided Predicate properly handles all type indices:

    markAllTypeIdxsAsCovered();

    return actionIf(LegalizeAction::Libcall, Predicate);

  }

  LegalizeRuleSet &libcallFor(std::initializer_list<LLT> Types) {

    return actionFor(LegalizeAction::Libcall, Types);

  }

  LegalizeRuleSet &

  libcallFor(std::initializer_list<std::pair<LLT, LLT>> Types) {

    return actionFor(LegalizeAction::Libcall, Types);

  }

  LegalizeRuleSet &

  libcallForCartesianProduct(std::initializer_list<LLT> Types) {

    return actionForCartesianProduct(LegalizeAction::Libcall, Types);

  }

  LegalizeRuleSet &

  libcallForCartesianProduct(std::initializer_list<LLT> Types0,

                             std::initializer_list<LLT> Types1) {

    return actionForCartesianProduct(LegalizeAction::Libcall, Types0, Types1);

  }

  /// Widen the scalar to the one selected by the mutation if the predicate is

  /// true.

  LegalizeRuleSet &widenScalarIf(LegalityPredicate Predicate,

                                 LegalizeMutation Mutation) {

    // We have no choice but conservatively assume that an action with a

    // free-form user provided Predicate properly handles all type indices:

    markAllTypeIdxsAsCovered();

    return actionIf(LegalizeAction::WidenScalar, Predicate, Mutation);

  }

  /// Narrow the scalar to the one selected by the mutation if the predicate is

  /// true.

  LegalizeRuleSet &narrowScalarIf(LegalityPredicate Predicate,

                                  LegalizeMutation Mutation) {

    // We have no choice but conservatively assume that an action with a

    // free-form user provided Predicate properly handles all type indices:

    markAllTypeIdxsAsCovered();

    return actionIf(LegalizeAction::NarrowScalar, Predicate, Mutation);

  }

  /// Add more elements to reach the type selected by the mutation if the

  /// predicate is true.

  LegalizeRuleSet &moreElementsIf(LegalityPredicate Predicate,

                                  LegalizeMutation Mutation) {

    // We have no choice but conservatively assume that an action with a

    // free-form user provided Predicate properly handles all type indices:

    markAllTypeIdxsAsCovered();

    return actionIf(LegalizeAction::MoreElements, Predicate, Mutation);

  }

  /// Remove elements to reach the type selected by the mutation if the

  /// predicate is true.

  LegalizeRuleSet &fewerElementsIf(LegalityPredicate Predicate,

                                   LegalizeMutation Mutation) {

    // We have no choice but conservatively assume that an action with a

    // free-form user provided Predicate properly handles all type indices:

    markAllTypeIdxsAsCovered();

    return actionIf(LegalizeAction::FewerElements, Predicate, Mutation);

  }

  /// The instruction is unsupported.

  LegalizeRuleSet &unsupported() {

    return actionIf(LegalizeAction::Unsupported, always);

  }

  LegalizeRuleSet &unsupportedIf(LegalityPredicate Predicate) {

    return actionIf(LegalizeAction::Unsupported, Predicate);

  }

  LegalizeRuleSet &unsupportedIfMemSizeNotPow2() {

    return actionIf(LegalizeAction::Unsupported,

                    LegalityPredicates::memSizeInBytesNotPow2(0));

  }

  LegalizeRuleSet &customIf(LegalityPredicate Predicate) {

    // We have no choice but conservatively assume that a custom action with a

    // free-form user provided Predicate properly handles all type indices:

    markAllTypeIdxsAsCovered();

    return actionIf(LegalizeAction::Custom, Predicate);

  }

  LegalizeRuleSet &customFor(std::initializer_list<LLT> Types) {

    return actionFor(LegalizeAction::Custom, Types);

  }

  LegalizeRuleSet &customForCartesianProduct(std::initializer_list<LLT> Types) {

    return actionForCartesianProduct(LegalizeAction::Custom, Types);

  }

  LegalizeRuleSet &

  customForCartesianProduct(std::initializer_list<LLT> Types0,

                            std::initializer_list<LLT> Types1) {

    return actionForCartesianProduct(LegalizeAction::Custom, Types0, Types1);

  }

  /// Widen the scalar to the next power of two that is at least MinSize.

  /// No effect if the type is not a scalar or is a power of two.

  LegalizeRuleSet &widenScalarToNextPow2(unsigned TypeIdx,

                                         unsigned MinSize = 0) {

    using namespace LegalityPredicates;

    return actionIf(LegalizeAction::WidenScalar, sizeNotPow2(typeIdx(TypeIdx)),

                    LegalizeMutations::widenScalarToNextPow2(TypeIdx, MinSize));

  }

  LegalizeRuleSet &narrowScalar(unsigned TypeIdx, LegalizeMutation Mutation) {

    using namespace LegalityPredicates;

    return actionIf(LegalizeAction::NarrowScalar, isScalar(typeIdx(TypeIdx)),

                    Mutation);

  }

  /// Ensure the scalar is at least as wide as Ty.

  LegalizeRuleSet &minScalar(unsigned TypeIdx, const LLT &Ty) {

    using namespace LegalityPredicates;

    using namespace LegalizeMutations;

    return actionIf(LegalizeAction::WidenScalar,

                    narrowerThan(TypeIdx, Ty.getSizeInBits()),

                    changeTo(typeIdx(TypeIdx), Ty));

  }

  /// Ensure the scalar is at most as wide as Ty.

  LegalizeRuleSet &maxScalar(unsigned TypeIdx, const LLT &Ty) {

    using namespace LegalityPredicates;

    using namespace LegalizeMutations;

    return actionIf(LegalizeAction::NarrowScalar,

                    widerThan(TypeIdx, Ty.getSizeInBits()),

                    changeTo(typeIdx(TypeIdx), Ty));

  }

  /// Conditionally limit the maximum size of the scalar.

  /// For example, when the maximum size of one type depends on the size of

  /// another such as extracting N bits from an M bit container.

  LegalizeRuleSet &maxScalarIf(LegalityPredicate Predicate, unsigned TypeIdx,

                               const LLT &Ty) {

    using namespace LegalityPredicates;

    using namespace LegalizeMutations;

    return actionIf(LegalizeAction::NarrowScalar,

                    [=](const LegalityQuery &Query) {

                      return widerThan(TypeIdx, Ty.getSizeInBits()) &&

                             Predicate(Query);

                    },

                    changeTo(typeIdx(TypeIdx), Ty));

  }

  /// Limit the range of scalar sizes to MinTy and MaxTy.

  LegalizeRuleSet &clampScalar(unsigned TypeIdx, const LLT &MinTy,

                               const LLT &MaxTy) {

    assert(MinTy.isScalar() && MaxTy.isScalar() && "Expected scalar types");

    return minScalar(TypeIdx, MinTy).maxScalar(TypeIdx, MaxTy);

  }

  /// Add more elements to the vector to reach the next power of two.

  /// No effect if the type is not a vector or the element count is a power of

  /// two.

  LegalizeRuleSet &moreElementsToNextPow2(unsigned TypeIdx) {

    using namespace LegalityPredicates;

    return actionIf(LegalizeAction::MoreElements,

                    numElementsNotPow2(typeIdx(TypeIdx)),

                    LegalizeMutations::moreElementsToNextPow2(TypeIdx));

  }

  /// Limit the number of elements in EltTy vectors to at least MinElements.

  LegalizeRuleSet &clampMinNumElements(unsigned TypeIdx, const LLT &EltTy,

                                       unsigned MinElements) {

    // Mark the type index as covered:

    typeIdx(TypeIdx);

    return actionIf(

        LegalizeAction::MoreElements,

        [=](const LegalityQuery &Query) {

          LLT VecTy = Query.Types[TypeIdx];

          return VecTy.isVector() && VecTy.getElementType() == EltTy &&

                 
VecTy.getNumElements() < MinElements5.03k
;

        },

        [=](const LegalityQuery &Query) {

          LLT VecTy = Query.Types[TypeIdx];

          return std::make_pair(

              TypeIdx, LLT::vector(MinElements, VecTy.getScalarSizeInBits()));

        });

  }

  /// Limit the number of elements in EltTy vectors to at most MaxElements.

  LegalizeRuleSet &clampMaxNumElements(unsigned TypeIdx, const LLT &EltTy,

                                       unsigned MaxElements) {

    // Mark the type index as covered:

    typeIdx(TypeIdx);

    return actionIf(

        LegalizeAction::FewerElements,

        [=](const LegalityQuery &Query) {

          LLT VecTy = Query.Types[TypeIdx];

          return VecTy.isVector() && VecTy.getElementType() == EltTy &&

                 
VecTy.getNumElements() > MaxElements5.03k
;

        },

        [=](const LegalityQuery &Query) {

          LLT VecTy = Query.Types[TypeIdx];

          return std::make_pair(

              TypeIdx, LLT::vector(MaxElements, VecTy.getScalarSizeInBits()));

        });

  }

  /// Limit the number of elements for the given vectors to at least MinTy's

  /// number of elements and at most MaxTy's number of elements.

  ///

  /// No effect if the type is not a vector or does not have the same element

  /// type as the constraints.

  /// The element type of MinTy and MaxTy must match.

  LegalizeRuleSet &clampNumElements(unsigned TypeIdx, const LLT &MinTy,

                                    const LLT &MaxTy) {

    assert(MinTy.getElementType() == MaxTy.getElementType() &&

           "Expected element types to agree");

    const LLT &EltTy = MinTy.getElementType();

    return clampMinNumElements(TypeIdx, EltTy, MinTy.getNumElements())

        .clampMaxNumElements(TypeIdx, EltTy, MaxTy.getNumElements());

  }

  /// Fallback on the previous implementation. This should only be used while

  /// porting a rule.

  LegalizeRuleSet &fallback() {

    add({always, LegalizeAction::UseLegacyRules});

    return *this;

  }

  /// Check if there is no type index which is obviously not handled by the

  /// LegalizeRuleSet in any way at all.

  /// \pre Type indices of the opcode form a dense [0, \p NumTypeIdxs) set.

  bool verifyTypeIdxsCoverage(unsigned NumTypeIdxs) const;

  /// Apply the ruleset to the given LegalityQuery.

  LegalizeActionStep apply(const LegalityQuery &Query) const;

};

class LegalizerInfo {

public:

  LegalizerInfo();

  virtual ~LegalizerInfo() = default;

  unsigned getOpcodeIdxForOpcode(unsigned Opcode) const;

  unsigned getActionDefinitionsIdx(unsigned Opcode) const;

  /// Compute any ancillary tables needed to quickly decide how an operation

  /// should be handled. This must be called after all "set*Action"methods but

  /// before any query is made or incorrect results may be returned.

  void computeTables();

  /// Perform simple self-diagnostic and assert if there is anything obviously

  /// wrong with the actions set up.

  void verify(const MCInstrInfo &MII) const;

  static bool needsLegalizingToDifferentSize(const LegalizeAction Action) {

    using namespace LegalizeActions;

    switch (Action) {

    case NarrowScalar:

    case WidenScalar:

    case FewerElements:

    case MoreElements:

    case Unsupported:

      return true;

    default:

      return false;

    }

  }

  using SizeAndAction = std::pair<uint16_t, LegalizeAction>;

  using SizeAndActionsVec = std::vector<SizeAndAction>;

  using SizeChangeStrategy =

      std::function<SizeAndActionsVec(const SizeAndActionsVec &v)>;

  /// More friendly way to set an action for common types that have an LLT

  /// representation.

  /// The LegalizeAction must be one for which NeedsLegalizingToDifferentSize

  /// returns false.

  void setAction(const InstrAspect &Aspect, LegalizeAction Action) {

    assert(!needsLegalizingToDifferentSize(Action));

    TablesInitialized = false;

    const unsigned OpcodeIdx = Aspect.Opcode - FirstOp;

    if (SpecifiedActions[OpcodeIdx].size() <= Aspect.Idx)

      SpecifiedActions[OpcodeIdx].resize(Aspect.Idx + 1);

    SpecifiedActions[OpcodeIdx][Aspect.Idx][Aspect.Type] = Action;

  }

  /// The setAction calls record the non-size-changing legalization actions

  /// to take on specificly-sized types. The SizeChangeStrategy defines what

  /// to do when the size of the type needs to be changed to reach a legally

  /// sized type (i.e., one that was defined through a setAction call).

  /// e.g.

  /// setAction ({G_ADD, 0, LLT::scalar(32)}, Legal);

  /// setLegalizeScalarToDifferentSizeStrategy(

  ///   G_ADD, 0, widenToLargerTypesAndNarrowToLargest);

  /// will end up defining getAction({G_ADD, 0, T}) to return the following 

  /// actions for different scalar types T:

  ///  LLT::scalar(1)..LLT::scalar(31): {WidenScalar, 0, LLT::scalar(32)}

  ///  LLT::scalar(32):                 {Legal, 0, LLT::scalar(32)}

  ///  LLT::scalar(33)..:               {NarrowScalar, 0, LLT::scalar(32)}

  ///

  /// If no SizeChangeAction gets defined, through this function,

  /// the default is unsupportedForDifferentSizes.

  void setLegalizeScalarToDifferentSizeStrategy(const unsigned Opcode,

                                                const unsigned TypeIdx,

                                                SizeChangeStrategy S) {

    const unsigned OpcodeIdx = Opcode - FirstOp;

    if (ScalarSizeChangeStrategies[OpcodeIdx].size() <= TypeIdx)

      ScalarSizeChangeStrategies[OpcodeIdx].resize(TypeIdx + 1);

    ScalarSizeChangeStrategies[OpcodeIdx][TypeIdx] = S;

  }

  /// See also setLegalizeScalarToDifferentSizeStrategy.

  /// This function allows to set the SizeChangeStrategy for vector elements.

  void setLegalizeVectorElementToDifferentSizeStrategy(const unsigned Opcode,

                                                       const unsigned TypeIdx,

                                                       SizeChangeStrategy S) {

    const unsigned OpcodeIdx = Opcode - FirstOp;

    if (VectorElementSizeChangeStrategies[OpcodeIdx].size() <= TypeIdx)

      VectorElementSizeChangeStrategies[OpcodeIdx].resize(TypeIdx + 1);

    VectorElementSizeChangeStrategies[OpcodeIdx][TypeIdx] = S;

  }

  /// A SizeChangeStrategy for the common case where legalization for a 

  /// particular operation consists of only supporting a specific set of type

  /// sizes. E.g.

  ///   setAction ({G_DIV, 0, LLT::scalar(32)}, Legal);

  ///   setAction ({G_DIV, 0, LLT::scalar(64)}, Legal);

  ///   setLegalizeScalarToDifferentSizeStrategy(

  ///     G_DIV, 0, unsupportedForDifferentSizes);

  /// will result in getAction({G_DIV, 0, T}) to return Legal for s32 and s64,

  /// and Unsupported for all other scalar types T.

  static SizeAndActionsVec

  unsupportedForDifferentSizes(const SizeAndActionsVec &v) {

    using namespace LegalizeActions;

    return increaseToLargerTypesAndDecreaseToLargest(v, Unsupported,

                                                     Unsupported);

  }

  /// A SizeChangeStrategy for the common case where legalization for a

  /// particular operation consists of widening the type to a large legal type,

  /// unless there is no such type and then instead it should be narrowed to the

  /// largest legal type.

  static SizeAndActionsVec

  widenToLargerTypesAndNarrowToLargest(const SizeAndActionsVec &v) {

    using namespace LegalizeActions;

    assert(v.size() > 0 &&

           "At least one size that can be legalized towards is needed"

           " for this SizeChangeStrategy");

    return increaseToLargerTypesAndDecreaseToLargest(v, WidenScalar,

                                                     NarrowScalar);

  }

  static SizeAndActionsVec

  widenToLargerTypesUnsupportedOtherwise(const SizeAndActionsVec &v) {

    using namespace LegalizeActions;

    return increaseToLargerTypesAndDecreaseToLargest(v, WidenScalar,

                                                     Unsupported);

  }

  static SizeAndActionsVec

  narrowToSmallerAndUnsupportedIfTooSmall(const SizeAndActionsVec &v) {

    using namespace LegalizeActions;

    return decreaseToSmallerTypesAndIncreaseToSmallest(v, NarrowScalar,

                                                       Unsupported);

  }

  static SizeAndActionsVec

  narrowToSmallerAndWidenToSmallest(const SizeAndActionsVec &v) {

    using namespace LegalizeActions;

    assert(v.size() > 0 &&

           "At least one size that can be legalized towards is needed"

           " for this SizeChangeStrategy");

    return decreaseToSmallerTypesAndIncreaseToSmallest(v, NarrowScalar,

                                                       WidenScalar);

  }

  /// A SizeChangeStrategy for the common case where legalization for a

  /// particular vector operation consists of having more elements in the

  /// vector, to a type that is legal. Unless there is no such type and then

  /// instead it should be legalized towards the widest vector that's still

  /// legal. E.g.

  ///   setAction({G_ADD, LLT::vector(8, 8)}, Legal);

  ///   setAction({G_ADD, LLT::vector(16, 8)}, Legal);

  ///   setAction({G_ADD, LLT::vector(2, 32)}, Legal);

  ///   setAction({G_ADD, LLT::vector(4, 32)}, Legal);

  ///   setLegalizeVectorElementToDifferentSizeStrategy(

  ///     G_ADD, 0, moreToWiderTypesAndLessToWidest);

  /// will result in the following getAction results:

  ///   * getAction({G_ADD, LLT::vector(8,8)}) returns

  ///       (Legal, vector(8,8)).

  ///   * getAction({G_ADD, LLT::vector(9,8)}) returns

  ///       (MoreElements, vector(16,8)).

  ///   * getAction({G_ADD, LLT::vector(8,32)}) returns

  ///       (FewerElements, vector(4,32)).

  static SizeAndActionsVec

  moreToWiderTypesAndLessToWidest(const SizeAndActionsVec &v) {

    using namespace LegalizeActions;

    return increaseToLargerTypesAndDecreaseToLargest(v, MoreElements,

                                                     FewerElements);

  }

  /// Helper function to implement many typical SizeChangeStrategy functions.

  static SizeAndActionsVec

  increaseToLargerTypesAndDecreaseToLargest(const SizeAndActionsVec &v,

                                            LegalizeAction IncreaseAction,

                                            LegalizeAction DecreaseAction);

  /// Helper function to implement many typical SizeChangeStrategy functions.

  static SizeAndActionsVec

  decreaseToSmallerTypesAndIncreaseToSmallest(const SizeAndActionsVec &v,

                                              LegalizeAction DecreaseAction,

                                              LegalizeAction IncreaseAction);

  /// Get the action definitions for the given opcode. Use this to run a

  /// LegalityQuery through the definitions.

  const LegalizeRuleSet &getActionDefinitions(unsigned Opcode) const;

  /// Get the action definition builder for the given opcode. Use this to define

  /// the action definitions.

  ///

  /// It is an error to request an opcode that has already been requested by the

  /// multiple-opcode variant.

  LegalizeRuleSet &getActionDefinitionsBuilder(unsigned Opcode);

  /// Get the action definition builder for the given set of opcodes. Use this

  /// to define the action definitions for multiple opcodes at once. The first

  /// opcode given will be considered the representative opcode and will hold

  /// the definitions whereas the other opcodes will be configured to refer to

  /// the representative opcode. This lowers memory requirements and very

  /// slightly improves performance.

  ///

  /// It would be very easy to introduce unexpected side-effects as a result of

  /// this aliasing if it were permitted to request different but intersecting

  /// sets of opcodes but that is difficult to keep track of. It is therefore an

  /// error to request the same opcode twice using this API, to request an

  /// opcode that already has definitions, or to use the single-opcode API on an

  /// opcode that has already been requested by this API.

  LegalizeRuleSet &

  getActionDefinitionsBuilder(std::initializer_list<unsigned> Opcodes);

  void aliasActionDefinitions(unsigned OpcodeTo, unsigned OpcodeFrom);

  /// Determine what action should be taken to legalize the described

  /// instruction. Requires computeTables to have been called.

  ///

  /// \returns a description of the next legalization step to perform.

  LegalizeActionStep getAction(const LegalityQuery &Query) const;

  /// Determine what action should be taken to legalize the given generic

  /// instruction.

  ///

  /// \returns a description of the next legalization step to perform.

  LegalizeActionStep getAction(const MachineInstr &MI,

                               const MachineRegisterInfo &MRI) const;

  bool isLegal(const MachineInstr &MI, const MachineRegisterInfo &MRI) const;

  virtual bool legalizeCustom(MachineInstr &MI,

                              MachineRegisterInfo &MRI,

                              MachineIRBuilder &MIRBuilder) const;

private:

  /// Determine what action should be taken to legalize the given generic

  /// instruction opcode, type-index and type. Requires computeTables to have

  /// been called.

  ///

  /// \returns a pair consisting of the kind of legalization that should be

  /// performed and the destination type.

  std::pair<LegalizeAction, LLT>

  getAspectAction(const InstrAspect &Aspect) const;

  /// The SizeAndActionsVec is a representation mapping between all natural

  /// numbers and an Action. The natural number represents the bit size of

  /// the InstrAspect. For example, for a target with native support for 32-bit

  /// and 64-bit additions, you'd express that as:

  /// setScalarAction(G_ADD, 0,

  ///           {{1, WidenScalar},  // bit sizes [ 1, 31[

  ///            {32, Legal},       // bit sizes [32, 33[

  ///            {33, WidenScalar}, // bit sizes [33, 64[

  ///            {64, Legal},       // bit sizes [64, 65[

  ///            {65, NarrowScalar} // bit sizes [65, +inf[

  ///           });

  /// It may be that only 64-bit pointers are supported on your target:

  /// setPointerAction(G_GEP, 0, LLT:pointer(1),

  ///           {{1, Unsupported},  // bit sizes [ 1, 63[

  ///            {64, Legal},       // bit sizes [64, 65[

  ///            {65, Unsupported}, // bit sizes [65, +inf[

  ///           });

  void setScalarAction(const unsigned Opcode, const unsigned TypeIndex,

                       const SizeAndActionsVec &SizeAndActions) {

    const unsigned OpcodeIdx = Opcode - FirstOp;

    SmallVector<SizeAndActionsVec, 1> &Actions = ScalarActions[OpcodeIdx];

    setActions(TypeIndex, Actions, SizeAndActions);

  }

  void setPointerAction(const unsigned Opcode, const unsigned TypeIndex,

                        const unsigned AddressSpace,

                        const SizeAndActionsVec &SizeAndActions) {

    const unsigned OpcodeIdx = Opcode - FirstOp;

    if (AddrSpace2PointerActions[OpcodeIdx].find(AddressSpace) ==

        AddrSpace2PointerActions[OpcodeIdx].end())

      AddrSpace2PointerActions[OpcodeIdx][AddressSpace] = {{}};

    SmallVector<SizeAndActionsVec, 1> &Actions =

        AddrSpace2PointerActions[OpcodeIdx].find(AddressSpace)->second;

    setActions(TypeIndex, Actions, SizeAndActions);

  }

  /// If an operation on a given vector type (say <M x iN>) isn't explicitly

  /// specified, we proceed in 2 stages. First we legalize the underlying scalar

  /// (so that there's at least one legal vector with that scalar), then we

  /// adjust the number of elements in the vector so that it is legal. The

  /// desired action in the first step is controlled by this function.

  void setScalarInVectorAction(const unsigned Opcode, const unsigned TypeIndex,

                               const SizeAndActionsVec &SizeAndActions) {

    unsigned OpcodeIdx = Opcode - FirstOp;

    SmallVector<SizeAndActionsVec, 1> &Actions =

        ScalarInVectorActions[OpcodeIdx];

    setActions(TypeIndex, Actions, SizeAndActions);

  }

  /// See also setScalarInVectorAction.

  /// This function let's you specify the number of elements in a vector that

  /// are legal for a legal element size.

  void setVectorNumElementAction(const unsigned Opcode,

                                 const unsigned TypeIndex,

                                 const unsigned ElementSize,

                                 const SizeAndActionsVec &SizeAndActions) {

    const unsigned OpcodeIdx = Opcode - FirstOp;

    if (NumElements2Actions[OpcodeIdx].find(ElementSize) ==

        NumElements2Actions[OpcodeIdx].end())

      NumElements2Actions[OpcodeIdx][ElementSize] = {{}};

    SmallVector<SizeAndActionsVec, 1> &Actions =

        NumElements2Actions[OpcodeIdx].find(ElementSize)->second;

    setActions(TypeIndex, Actions, SizeAndActions);

  }

  /// A partial SizeAndActionsVec potentially doesn't cover all bit sizes,

  /// i.e. it's OK if it doesn't start from size 1.

  static void checkPartialSizeAndActionsVector(const SizeAndActionsVec& v) {

    using namespace LegalizeActions;

#ifndef NDEBUG

    // The sizes should be in increasing order

    int prev_size = -1;

    for(auto SizeAndAction: v) {

      assert(SizeAndAction.first > prev_size);

      prev_size = SizeAndAction.first;

    }

    // - for every Widen action, there should be a larger bitsize that

    //   can be legalized towards (e.g. Legal, Lower, Libcall or Custom

    //   action).

    // - for every Narrow action, there should be a smaller bitsize that

    //   can be legalized towards.

    int SmallestNarrowIdx = -1;

    int LargestWidenIdx = -1;

    int SmallestLegalizableToSameSizeIdx = -1;

    int LargestLegalizableToSameSizeIdx = -1;

    for(size_t i=0; i<v.size(); ++i) {

      switch (v[i].second) {

        case FewerElements:

        case NarrowScalar:

          if (SmallestNarrowIdx == -1)

            SmallestNarrowIdx = i;

          break;

        case WidenScalar:

        case MoreElements:

          LargestWidenIdx = i;

          break;

        case Unsupported:

          break;

        default:

          if (SmallestLegalizableToSameSizeIdx == -1)

            SmallestLegalizableToSameSizeIdx = i;

          LargestLegalizableToSameSizeIdx = i;

      }