llvm/mlir/include/mlir/IR/Iterators.h

//===- Iterators.h - IR iterators for IR visitors ---------------*- 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
//
//===----------------------------------------------------------------------===//
//
// The iterators defined in this file can be used together with IR visitors.
// Note: These iterators cannot be defined in Visitors.h because that would
// introduce a cyclic header dependency due to Operation.h.
//
//===----------------------------------------------------------------------===//

#ifndef MLIR_IR_ITERATORS_H
#define MLIR_IR_ITERATORS_H

#include "mlir/IR/Operation.h"
#include "mlir/IR/RegionGraphTraits.h"
#include "mlir/IR/RegionKindInterface.h"
#include "mlir/Support/LLVM.h"

#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/PostOrderIterator.h"

namespace mlir {
/// This iterator enumerates elements in "reverse" order. It is a wrapper around
/// llvm::reverse.
struct ReverseIterator { … };

/// This iterator enumerates elements according to their dominance relationship.
/// Operations and regions are enumerated in "forward" order. Blocks are
/// enumerated according to their successor relationship. Unreachable blocks are
/// not enumerated. Blocks may not be erased during the traversal.
///
/// Note: If `NoGraphRegions` is set to "true", this iterator asserts that each
/// visited region has SSA dominance. In either case, the ops in such regions
/// are visited in forward order, but for regions without SSA dominance this
/// does not guarantee that defining ops are visited before their users.
template <bool NoGraphRegions = false>
struct ForwardDominanceIterator { … };

/// This iterator enumerates elements according to their reverse dominance
/// relationship. Operations and regions are enumerated in "reverse" order.
/// Blocks are enumerated according to their successor relationship, but
/// post-order. I.e., a block is visited after its successors have been visited.
/// Cycles in the block graph are broken in an unspecified way. Unreachable
/// blocks are not enumerated. Blocks may not be erased during the traversal.
///
/// Note: If `NoGraphRegions` is set to "true", this iterator asserts that each
/// visited region has SSA dominance.
template <bool NoGraphRegions = false>
struct ReverseDominanceIterator { … };
} // namespace mlir

#endif // MLIR_IR_ITERATORS_H