llvm/mlir/include/mlir/IR/OpDefinition.h

//===- OpDefinition.h - Classes for defining concrete Op types --*- 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 implements helper classes for implementing the "Op" types.  This
// includes the Op type, which is the base class for Op class definitions,
// as well as number of traits in the OpTrait namespace that provide a
// declarative way to specify properties of Ops.
//
// The purpose of these types are to allow light-weight implementation of
// concrete ops (like DimOp) with very little boilerplate.
//
//===----------------------------------------------------------------------===//

#ifndef MLIR_IR_OPDEFINITION_H
#define MLIR_IR_OPDEFINITION_H

#include "mlir/IR/Dialect.h"
#include "mlir/IR/ODSSupport.h"
#include "mlir/IR/Operation.h"
#include "llvm/Support/PointerLikeTypeTraits.h"

#include <optional>
#include <type_traits>

namespace mlir {
class Builder;
class OpBuilder;

/// This class implements `Optional` functionality for ParseResult. We don't
/// directly use Optional here, because it provides an implicit conversion
/// to 'bool' which we want to avoid. This class is used to implement tri-state
/// 'parseOptional' functions that may have a failure mode when parsing that
/// shouldn't be attributed to "not present".
class OptionalParseResult { … };

// These functions are out-of-line utilities, which avoids them being template
// instantiated/duplicated.
namespace impl {
/// Insert an operation, generated by `buildTerminatorOp`, at the end of the
/// region's only block if it does not have a terminator already. If the region
/// is empty, insert a new block first. `buildTerminatorOp` should return the
/// terminator operation to insert.
void ensureRegionTerminator(
    Region &region, OpBuilder &builder, Location loc,
    function_ref<Operation *(OpBuilder &, Location)> buildTerminatorOp);
void ensureRegionTerminator(
    Region &region, Builder &builder, Location loc,
    function_ref<Operation *(OpBuilder &, Location)> buildTerminatorOp);

} // namespace impl

/// Structure used by default as a "marker" when no "Properties" are set on an
/// Operation.
struct EmptyProperties { … };

/// Traits to detect whether an Operation defined a `Properties` type, otherwise
/// it'll default to `EmptyProperties`.
template <class Op, class = void>
struct PropertiesSelector { … };
PropertiesSelector<Op, std::void_t<typename Op::Properties>>;

/// This is the concrete base class that holds the operation pointer and has
/// non-generic methods that only depend on State (to avoid having them
/// instantiated on template types that don't affect them.
///
/// This also has the fallback implementations of customization hooks for when
/// they aren't customized.
class OpState { … };

// Allow comparing operators.
inline bool operator==(OpState lhs, OpState rhs) { … }
inline bool operator!=(OpState lhs, OpState rhs) { … }

raw_ostream &operator<<(raw_ostream &os, OpFoldResult ofr);

/// This class represents a single result from folding an operation.
class OpFoldResult : public PointerUnion<Attribute, Value> { … };

// Temporarily exit the MLIR namespace to add casting support as later code in
// this uses it. The CastInfo must come after the OpFoldResult definition and
// before any cast function calls depending on CastInfo.

} // namespace mlir

namespace llvm {

// Allow llvm::cast style functions.
CastInfo<To, mlir::OpFoldResult>;

CastInfo<To, const mlir::OpFoldResult>;

} // namespace llvm

namespace mlir {

/// Allow printing to a stream.
inline raw_ostream &operator<<(raw_ostream &os, OpFoldResult ofr) { … }
/// Allow printing to a stream.
inline raw_ostream &operator<<(raw_ostream &os, OpState op) { … }

//===----------------------------------------------------------------------===//
// Operation Trait Types
//===----------------------------------------------------------------------===//

namespace OpTrait {

// These functions are out-of-line implementations of the methods in the
// corresponding trait classes.  This avoids them being template
// instantiated/duplicated.
namespace impl {
LogicalResult foldCommutative(Operation *op, ArrayRef<Attribute> operands,
                              SmallVectorImpl<OpFoldResult> &results);
OpFoldResult foldIdempotent(Operation *op);
OpFoldResult foldInvolution(Operation *op);
LogicalResult verifyZeroOperands(Operation *op);
LogicalResult verifyOneOperand(Operation *op);
LogicalResult verifyNOperands(Operation *op, unsigned numOperands);
LogicalResult verifyIsIdempotent(Operation *op);
LogicalResult verifyIsInvolution(Operation *op);
LogicalResult verifyAtLeastNOperands(Operation *op, unsigned numOperands);
LogicalResult verifyOperandsAreFloatLike(Operation *op);
LogicalResult verifyOperandsAreSignlessIntegerLike(Operation *op);
LogicalResult verifySameTypeOperands(Operation *op);
LogicalResult verifyZeroRegions(Operation *op);
LogicalResult verifyOneRegion(Operation *op);
LogicalResult verifyNRegions(Operation *op, unsigned numRegions);
LogicalResult verifyAtLeastNRegions(Operation *op, unsigned numRegions);
LogicalResult verifyZeroResults(Operation *op);
LogicalResult verifyOneResult(Operation *op);
LogicalResult verifyNResults(Operation *op, unsigned numOperands);
LogicalResult verifyAtLeastNResults(Operation *op, unsigned numOperands);
LogicalResult verifySameOperandsShape(Operation *op);
LogicalResult verifySameOperandsAndResultShape(Operation *op);
LogicalResult verifySameOperandsElementType(Operation *op);
LogicalResult verifySameOperandsAndResultElementType(Operation *op);
LogicalResult verifySameOperandsAndResultType(Operation *op);
LogicalResult verifySameOperandsAndResultRank(Operation *op);
LogicalResult verifyResultsAreBoolLike(Operation *op);
LogicalResult verifyResultsAreFloatLike(Operation *op);
LogicalResult verifyResultsAreSignlessIntegerLike(Operation *op);
LogicalResult verifyIsTerminator(Operation *op);
LogicalResult verifyZeroSuccessors(Operation *op);
LogicalResult verifyOneSuccessor(Operation *op);
LogicalResult verifyNSuccessors(Operation *op, unsigned numSuccessors);
LogicalResult verifyAtLeastNSuccessors(Operation *op, unsigned numSuccessors);
LogicalResult verifyValueSizeAttr(Operation *op, StringRef attrName,
                                  StringRef valueGroupName,
                                  size_t expectedCount);
LogicalResult verifyOperandSizeAttr(Operation *op, StringRef sizeAttrName);
LogicalResult verifyResultSizeAttr(Operation *op, StringRef sizeAttrName);
LogicalResult verifyNoRegionArguments(Operation *op);
LogicalResult verifyElementwise(Operation *op);
LogicalResult verifyIsIsolatedFromAbove(Operation *op);
} // namespace impl

/// Helper class for implementing traits.  Clients are not expected to interact
/// with this directly, so its members are all protected.
template <typename ConcreteType, template <typename> class TraitType>
class TraitBase { … };

//===----------------------------------------------------------------------===//
// Operand Traits

namespace detail {
/// Utility trait base that provides accessors for derived traits that have
/// multiple operands.
template <typename ConcreteType, template <typename> class TraitType>
struct MultiOperandTraitBase : public TraitBase<ConcreteType, TraitType> { … };
} // namespace detail

/// `verifyInvariantsImpl` verifies the invariants like the types, attrs, .etc.
/// It should be run after core traits and before any other user defined traits.
/// In order to run it in the correct order, wrap it with OpInvariants trait so
/// that tblgen will be able to put it in the right order.
template <typename ConcreteType>
class OpInvariants : public TraitBase<ConcreteType, OpInvariants> { … };

/// This class provides the API for ops that are known to have no
/// SSA operand.
template <typename ConcreteType>
class ZeroOperands : public TraitBase<ConcreteType, ZeroOperands> { … };

/// This class provides the API for ops that are known to have exactly one
/// SSA operand.
template <typename ConcreteType>
class OneOperand : public TraitBase<ConcreteType, OneOperand> { … };

/// This class provides the API for ops that are known to have a specified
/// number of operands.  This is used as a trait like this:
///
///   class FooOp : public Op<FooOp, OpTrait::NOperands<2>::Impl> {
///
template <unsigned N>
class NOperands { … };

/// This class provides the API for ops that are known to have a at least a
/// specified number of operands.  This is used as a trait like this:
///
///   class FooOp : public Op<FooOp, OpTrait::AtLeastNOperands<2>::Impl> {
///
template <unsigned N>
class AtLeastNOperands { … };

/// This class provides the API for ops which have an unknown number of
/// SSA operands.
template <typename ConcreteType>
class VariadicOperands
    : public detail::MultiOperandTraitBase<ConcreteType, VariadicOperands> { … };

//===----------------------------------------------------------------------===//
// Region Traits

/// This class provides verification for ops that are known to have zero
/// regions.
template <typename ConcreteType>
class ZeroRegions : public TraitBase<ConcreteType, ZeroRegions> { … };

namespace detail {
/// Utility trait base that provides accessors for derived traits that have
/// multiple regions.
template <typename ConcreteType, template <typename> class TraitType>
struct MultiRegionTraitBase : public TraitBase<ConcreteType, TraitType> { … };
} // namespace detail

/// This class provides APIs for ops that are known to have a single region.
template <typename ConcreteType>
class OneRegion : public TraitBase<ConcreteType, OneRegion> { … };

/// This class provides the API for ops that are known to have a specified
/// number of regions.
template <unsigned N>
class NRegions { … };

/// This class provides APIs for ops that are known to have at least a specified
/// number of regions.
template <unsigned N>
class AtLeastNRegions { … };

/// This class provides the API for ops which have an unknown number of
/// regions.
template <typename ConcreteType>
class VariadicRegions
    : public detail::MultiRegionTraitBase<ConcreteType, VariadicRegions> { … };

//===----------------------------------------------------------------------===//
// Result Traits

/// This class provides return value APIs for ops that are known to have
/// zero results.
template <typename ConcreteType>
class ZeroResults : public TraitBase<ConcreteType, ZeroResults> { … };

namespace detail {
/// Utility trait base that provides accessors for derived traits that have
/// multiple results.
template <typename ConcreteType, template <typename> class TraitType>
struct MultiResultTraitBase : public TraitBase<ConcreteType, TraitType> { … };
} // namespace detail

/// This class provides return value APIs for ops that are known to have a
/// single result.  ResultType is the concrete type returned by getType().
template <typename ConcreteType>
class OneResult : public TraitBase<ConcreteType, OneResult> { … };

/// This trait is used for return value APIs for ops that are known to have a
/// specific type other than `Type`.  This allows the "getType()" member to be
/// more specific for an op.  This should be used in conjunction with OneResult,
/// and occur in the trait list before OneResult.
template <typename ResultType>
class OneTypedResult { … };

/// This class provides the API for ops that are known to have a specified
/// number of results.  This is used as a trait like this:
///
///   class FooOp : public Op<FooOp, OpTrait::NResults<2>::Impl> {
///
template <unsigned N>
class NResults { … };

/// This class provides the API for ops that are known to have at least a
/// specified number of results.  This is used as a trait like this:
///
///   class FooOp : public Op<FooOp, OpTrait::AtLeastNResults<2>::Impl> {
///
template <unsigned N>
class AtLeastNResults { … };

/// This class provides the API for ops which have an unknown number of
/// results.
template <typename ConcreteType>
class VariadicResults
    : public detail::MultiResultTraitBase<ConcreteType, VariadicResults> { … };

//===----------------------------------------------------------------------===//
// Terminator Traits

/// This class indicates that the regions associated with this op don't have
/// terminators.
template <typename ConcreteType>
class NoTerminator : public TraitBase<ConcreteType, NoTerminator> { … };

/// This class provides the API for ops that are known to be terminators.
template <typename ConcreteType>
class IsTerminator : public TraitBase<ConcreteType, IsTerminator> { … };

/// This class provides verification for ops that are known to have zero
/// successors.
template <typename ConcreteType>
class ZeroSuccessors : public TraitBase<ConcreteType, ZeroSuccessors> { … };

namespace detail {
/// Utility trait base that provides accessors for derived traits that have
/// multiple successors.
template <typename ConcreteType, template <typename> class TraitType>
struct MultiSuccessorTraitBase : public TraitBase<ConcreteType, TraitType> { … };
} // namespace detail

/// This class provides APIs for ops that are known to have a single successor.
template <typename ConcreteType>
class OneSuccessor : public TraitBase<ConcreteType, OneSuccessor> { … };

/// This class provides the API for ops that are known to have a specified
/// number of successors.
template <unsigned N>
class NSuccessors { … };

/// This class provides APIs for ops that are known to have at least a specified
/// number of successors.
template <unsigned N>
class AtLeastNSuccessors { … };

/// This class provides the API for ops which have an unknown number of
/// successors.
template <typename ConcreteType>
class VariadicSuccessors
    : public detail::MultiSuccessorTraitBase<ConcreteType, VariadicSuccessors> { … };

//===----------------------------------------------------------------------===//
// SingleBlock

/// This class provides APIs and verifiers for ops with regions having a single
/// block.
template <typename ConcreteType>
struct SingleBlock : public TraitBase<ConcreteType, SingleBlock> { … };

//===----------------------------------------------------------------------===//
// SingleBlockImplicitTerminator

/// This class provides APIs and verifiers for ops with regions having a single
/// block that must terminate with `TerminatorOpType`.
template <typename TerminatorOpType>
struct SingleBlockImplicitTerminator { … };

/// Check is an op defines the `ImplicitTerminatorOpT` member. This is intended
/// to be used with `llvm::is_detected`.
has_implicit_terminator_t;

/// Support to check if an operation has the SingleBlockImplicitTerminator
/// trait. We can't just use `hasTrait` because this class is templated on a
/// specific terminator op.
template <class Op, bool hasTerminator =
                        llvm::is_detected<has_implicit_terminator_t, Op>::value>
struct hasSingleBlockImplicitTerminator { … };
hasSingleBlockImplicitTerminator<Op, false>;

//===----------------------------------------------------------------------===//
// Misc Traits

/// This class provides verification for ops that are known to have the same
/// operand shape: all operands are scalars, vectors/tensors of the same
/// shape.
template <typename ConcreteType>
class SameOperandsShape : public TraitBase<ConcreteType, SameOperandsShape> { … };

/// This class provides verification for ops that are known to have the same
/// operand and result shape: both are scalars, vectors/tensors of the same
/// shape.
template <typename ConcreteType>
class SameOperandsAndResultShape
    : public TraitBase<ConcreteType, SameOperandsAndResultShape> { … };

/// This class provides verification for ops that are known to have the same
/// operand element type (or the type itself if it is scalar).
///
template <typename ConcreteType>
class SameOperandsElementType
    : public TraitBase<ConcreteType, SameOperandsElementType> { … };

/// This class provides verification for ops that are known to have the same
/// operand and result element type (or the type itself if it is scalar).
///
template <typename ConcreteType>
class SameOperandsAndResultElementType
    : public TraitBase<ConcreteType, SameOperandsAndResultElementType> { … };

/// This class provides verification for ops that are known to have the same
/// operand and result type.
///
/// Note: this trait subsumes the SameOperandsAndResultShape and
/// SameOperandsAndResultElementType traits.
template <typename ConcreteType>
class SameOperandsAndResultType
    : public TraitBase<ConcreteType, SameOperandsAndResultType> { … };

/// This class verifies that op has same ranks for all
/// operands and results types, if known.
template <typename ConcreteType>
class SameOperandsAndResultRank
    : public TraitBase<ConcreteType, SameOperandsAndResultRank> { … };

/// This class verifies that any results of the specified op have a boolean
/// type, a vector thereof, or a tensor thereof.
template <typename ConcreteType>
class ResultsAreBoolLike : public TraitBase<ConcreteType, ResultsAreBoolLike> { … };

/// This class verifies that any results of the specified op have a floating
/// point type, a vector thereof, or a tensor thereof.
template <typename ConcreteType>
class ResultsAreFloatLike
    : public TraitBase<ConcreteType, ResultsAreFloatLike> { … };

/// This class verifies that any results of the specified op have a signless
/// integer or index type, a vector thereof, or a tensor thereof.
template <typename ConcreteType>
class ResultsAreSignlessIntegerLike
    : public TraitBase<ConcreteType, ResultsAreSignlessIntegerLike> { … };

/// This class adds property that the operation is commutative.
template <typename ConcreteType>
class IsCommutative : public TraitBase<ConcreteType, IsCommutative> { … };

/// This class adds property that the operation is an involution.
/// This means a unary to unary operation "f" that satisfies f(f(x)) = x
template <typename ConcreteType>
class IsInvolution : public TraitBase<ConcreteType, IsInvolution> { … };

/// This class adds property that the operation is idempotent.
/// This means a unary to unary operation "f" that satisfies f(f(x)) = f(x),
/// or a binary operation "g" that satisfies g(x, x) = x.
template <typename ConcreteType>
class IsIdempotent : public TraitBase<ConcreteType, IsIdempotent> { … };

/// This class verifies that all operands of the specified op have a float type,
/// a vector thereof, or a tensor thereof.
template <typename ConcreteType>
class OperandsAreFloatLike
    : public TraitBase<ConcreteType, OperandsAreFloatLike> { … };

/// This class verifies that all operands of the specified op have a signless
/// integer or index type, a vector thereof, or a tensor thereof.
template <typename ConcreteType>
class OperandsAreSignlessIntegerLike
    : public TraitBase<ConcreteType, OperandsAreSignlessIntegerLike> { … };

/// This class verifies that all operands of the specified op have the same
/// type.
template <typename ConcreteType>
class SameTypeOperands : public TraitBase<ConcreteType, SameTypeOperands> { … };

/// This class provides the API for a sub-set of ops that are known to be
/// constant-like. These are non-side effecting operations with one result and
/// zero operands that can always be folded to a specific attribute value.
template <typename ConcreteType>
class ConstantLike : public TraitBase<ConcreteType, ConstantLike> { … };

/// This class provides the API for ops that are known to be isolated from
/// above.
template <typename ConcreteType>
class IsIsolatedFromAbove
    : public TraitBase<ConcreteType, IsIsolatedFromAbove> { … };

/// A trait of region holding operations that defines a new scope for polyhedral
/// optimization purposes. Any SSA values of 'index' type that either dominate
/// such an operation or are used at the top-level of such an operation
/// automatically become valid symbols for the polyhedral scope defined by that
/// operation. For more details, see `Traits.md#AffineScope`.
template <typename ConcreteType>
class AffineScope : public TraitBase<ConcreteType, AffineScope> { … };

/// A trait of region holding operations that define a new scope for automatic
/// allocations, i.e., allocations that are freed when control is transferred
/// back from the operation's region. Any operations performing such allocations
/// (for eg. memref.alloca) will have their allocations automatically freed at
/// their closest enclosing operation with this trait.
template <typename ConcreteType>
class AutomaticAllocationScope
    : public TraitBase<ConcreteType, AutomaticAllocationScope> { … };

/// This class provides a verifier for ops that are expecting their parent
/// to be one of the given parent ops
template <typename... ParentOpTypes>
struct HasParent { … };

/// A trait for operations that have an attribute specifying operand segments.
///
/// Certain operations can have multiple variadic operands and their size
/// relationship is not always known statically. For such cases, we need
/// a per-op-instance specification to divide the operands into logical groups
/// or segments. This can be modeled by attributes. The attribute will be named
/// as `operandSegmentSizes`.
///
/// This trait verifies the attribute for specifying operand segments has
/// the correct type (1D vector) and values (non-negative), etc.
template <typename ConcreteType>
class AttrSizedOperandSegments
    : public TraitBase<ConcreteType, AttrSizedOperandSegments> { … };

/// Similar to AttrSizedOperandSegments but used for results.
template <typename ConcreteType>
class AttrSizedResultSegments
    : public TraitBase<ConcreteType, AttrSizedResultSegments> { … };

/// This trait provides a verifier for ops that are expecting their regions to
/// not have any arguments
template <typename ConcrentType>
struct NoRegionArguments : public TraitBase<ConcrentType, NoRegionArguments> { … };

// This trait is used to flag operations that consume or produce
// values of `MemRef` type where those references can be 'normalized'.
// TODO: Right now, the operands of an operation are either all normalizable,
// or not. In the future, we may want to allow some of the operands to be
// normalizable.
template <typename ConcrentType>
struct MemRefsNormalizable
    : public TraitBase<ConcrentType, MemRefsNormalizable> { … };

/// This trait tags element-wise ops on vectors or tensors.
///
/// NOTE: Not all ops that are "elementwise" in some abstract sense satisfy this
/// trait. In particular, broadcasting behavior is not allowed.
///
/// An `Elementwise` op must satisfy the following properties:
///
/// 1. If any result is a vector/tensor then at least one operand must also be a
///    vector/tensor.
/// 2. If any operand is a vector/tensor then there must be at least one result
///    and all results must be vectors/tensors.
/// 3. All operand and result vector/tensor types must be of the same shape. The
///    shape may be dynamic in which case the op's behaviour is undefined for
///    non-matching shapes.
/// 4. The operation must be elementwise on its vector/tensor operands and
///    results. When applied to single-element vectors/tensors, the result must
///    be the same per elememnt.
///
/// TODO: Avoid hardcoding vector/tensor, and generalize this trait to a new
/// interface `ElementwiseTypeInterface` that describes the container types for
/// which the operation is elementwise.
///
/// Rationale:
/// - 1. and 2. guarantee a well-defined iteration space and exclude the cases
///   of 0 non-scalar operands or 0 non-scalar results, which complicate a
///   generic definition of the iteration space.
/// - 3. guarantees that folding can be done across scalars/vectors/tensors with
///   the same pattern, as otherwise lots of special handling for type
///   mismatches would be needed.
/// - 4. guarantees that no error handling is needed. Higher-level dialects
///   should reify any needed guards or error handling code before lowering to
///   an `Elementwise` op.
template <typename ConcreteType>
struct Elementwise : public TraitBase<ConcreteType, Elementwise> { … };

/// This trait tags `Elementwise` operatons that can be systematically
/// scalarized. All vector/tensor operands and results are then replaced by
/// scalars of the respective element type. Semantically, this is the operation
/// on a single element of the vector/tensor.
///
/// Rationale:
/// Allow to define the vector/tensor semantics of elementwise operations based
/// on the same op's behavior on scalars. This provides a constructive procedure
/// for IR transformations to, e.g., create scalar loop bodies from tensor ops.
///
/// Example:
/// ```
/// %tensor_select = "arith.select"(%pred_tensor, %true_val, %false_val)
///                      : (tensor<?xi1>, tensor<?xf32>, tensor<?xf32>)
///                      -> tensor<?xf32>
/// ```
/// can be scalarized to
///
/// ```
/// %scalar_select = "arith.select"(%pred, %true_val_scalar, %false_val_scalar)
///                      : (i1, f32, f32) -> f32
/// ```
template <typename ConcreteType>
struct Scalarizable : public TraitBase<ConcreteType, Scalarizable> { … };

/// This trait tags `Elementwise` operatons that can be systematically
/// vectorized. All scalar operands and results are then replaced by vectors
/// with the respective element type. Semantically, this is the operation on
/// multiple elements simultaneously. See also `Tensorizable`.
///
/// Rationale:
/// Provide the reverse to `Scalarizable` which, when chained together, allows
/// reasoning about the relationship between the tensor and vector case.
/// Additionally, it permits reasoning about promoting scalars to vectors via
/// broadcasting in cases like `%select_scalar_pred` below.
template <typename ConcreteType>
struct Vectorizable : public TraitBase<ConcreteType, Vectorizable> { … };

/// This trait tags `Elementwise` operatons that can be systematically
/// tensorized. All scalar operands and results are then replaced by tensors
/// with the respective element type. Semantically, this is the operation on
/// multiple elements simultaneously. See also `Vectorizable`.
///
/// Rationale:
/// Provide the reverse to `Scalarizable` which, when chained together, allows
/// reasoning about the relationship between the tensor and vector case.
/// Additionally, it permits reasoning about promoting scalars to tensors via
/// broadcasting in cases like `%select_scalar_pred` below.
///
/// Examples:
/// ```
/// %scalar = "arith.addf"(%a, %b) : (f32, f32) -> f32
/// ```
/// can be tensorized to
/// ```
/// %tensor = "arith.addf"(%a, %b) : (tensor<?xf32>, tensor<?xf32>)
///               -> tensor<?xf32>
/// ```
///
/// ```
/// %scalar_pred = "arith.select"(%pred, %true_val, %false_val)
///                    : (i1, tensor<?xf32>, tensor<?xf32>) -> tensor<?xf32>
/// ```
/// can be tensorized to
/// ```
/// %tensor_pred = "arith.select"(%pred, %true_val, %false_val)
///                    : (tensor<?xi1>, tensor<?xf32>, tensor<?xf32>)
///                    -> tensor<?xf32>
/// ```
template <typename ConcreteType>
struct Tensorizable : public TraitBase<ConcreteType, Tensorizable> { … };

/// Together, `Elementwise`, `Scalarizable`, `Vectorizable`, and `Tensorizable`
/// provide an easy way for scalar operations to conveniently generalize their
/// behavior to vectors/tensors, and systematize conversion between these forms.
bool hasElementwiseMappableTraits(Operation *op);

} // namespace OpTrait

//===----------------------------------------------------------------------===//
// Internal Trait Utilities
//===----------------------------------------------------------------------===//

namespace op_definition_impl {
//===----------------------------------------------------------------------===//
// Trait Existence

/// Returns true if this given Trait ID matches the IDs of any of the provided
/// trait types `Traits`.
template <template <typename T> class... Traits>
inline bool hasTrait(TypeID traitID) { … }
template <>
inline bool hasTrait<>(TypeID traitID) { … }

//===----------------------------------------------------------------------===//
// Trait Folding

/// Trait to check if T provides a 'foldTrait' method for single result
/// operations.
has_single_result_fold_trait;
detect_has_single_result_fold_trait;
/// Trait to check if T provides a general 'foldTrait' method.
has_fold_trait;
detect_has_fold_trait;
/// Trait to check if T provides any `foldTrait` method.
detect_has_any_fold_trait;

/// Returns the result of folding a trait that implements a `foldTrait` function
/// that is specialized for operations that have a single result.
template <typename Trait>
static std::enable_if_t<detect_has_single_result_fold_trait<Trait>::value,
                        LogicalResult>
foldTrait(Operation *op, ArrayRef<Attribute> operands,
          SmallVectorImpl<OpFoldResult> &results) { … }
/// Returns the result of folding a trait that implements a generalized
/// `foldTrait` function that is supports any operation type.
template <typename Trait>
static std::enable_if_t<detect_has_fold_trait<Trait>::value, LogicalResult>
foldTrait(Operation *op, ArrayRef<Attribute> operands,
          SmallVectorImpl<OpFoldResult> &results) { … }
template <typename Trait>
static inline std::enable_if_t<!detect_has_any_fold_trait<Trait>::value,
                               LogicalResult>
foldTrait(Operation *, ArrayRef<Attribute>, SmallVectorImpl<OpFoldResult> &) { … }

/// Given a tuple type containing a set of traits, return the result of folding
/// the given operation.
template <typename... Ts>
static LogicalResult foldTraits(Operation *op, ArrayRef<Attribute> operands,
                                SmallVectorImpl<OpFoldResult> &results) { … }

//===----------------------------------------------------------------------===//
// Trait Verification

/// Trait to check if T provides a `verifyTrait` method.
has_verify_trait;
detect_has_verify_trait;

/// Trait to check if T provides a `verifyTrait` method.
has_verify_region_trait;
detect_has_verify_region_trait;

/// Verify the given trait if it provides a verifier.
template <typename T>
std::enable_if_t<detect_has_verify_trait<T>::value, LogicalResult>
verifyTrait(Operation *op) { … }
template <typename T>
inline std::enable_if_t<!detect_has_verify_trait<T>::value, LogicalResult>
verifyTrait(Operation *) { … }

/// Given a set of traits, return the result of verifying the given operation.
template <typename... Ts>
LogicalResult verifyTraits(Operation *op) { … }

/// Verify the given trait if it provides a region verifier.
template <typename T>
std::enable_if_t<detect_has_verify_region_trait<T>::value, LogicalResult>
verifyRegionTrait(Operation *op) { … }
template <typename T>
inline std::enable_if_t<!detect_has_verify_region_trait<T>::value,
                        LogicalResult>
verifyRegionTrait(Operation *) { … }

/// Given a set of traits, return the result of verifying the regions of the
/// given operation.
template <typename... Ts>
LogicalResult verifyRegionTraits(Operation *op) { … }
} // namespace op_definition_impl

//===----------------------------------------------------------------------===//
// Operation Definition classes
//===----------------------------------------------------------------------===//

/// This provides public APIs that all operations should have.  The template
/// argument 'ConcreteType' should be the concrete type by CRTP and the others
/// are base classes by the policy pattern.
template <typename ConcreteType, template <typename T> class... Traits>
class Op : public OpState, public Traits<ConcreteType>... { … };

/// This class represents the base of an operation interface. See the definition
/// of `detail::Interface` for requirements on the `Traits` type.
template <typename ConcreteType, typename Traits>
class OpInterface
    : public detail::Interface<ConcreteType, Operation *, Traits,
                               Op<ConcreteType>, OpTrait::TraitBase> { … };

} // namespace mlir

namespace llvm {

DenseMapInfo<T, std::enable_if_t<std::is_base_of<mlir::OpState, T>::value && !mlir::detail::IsInterface<T>::value>>;
} // namespace llvm

#endif