llvm/mlir/lib/Transforms/Utils/ControlFlowSinkUtils.cpp

//===- ControlFlowSinkUtils.cpp - Code to perform control-flow sinking ----===//
//
// 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 utilities for control-flow sinking. Control-flow
// sinking moves operations whose only uses are in conditionally-executed blocks
// into those blocks so that they aren't executed on paths where their results
// are not needed.
//
// Control-flow sinking is not implemented on BranchOpInterface because
// sinking ops into the successors of branch operations may move ops into loops.
// It is idiomatic MLIR to perform optimizations at IR levels that readily
// provide the necessary information.
//
//===----------------------------------------------------------------------===//

#include "mlir/Transforms/ControlFlowSinkUtils.h"
#include "mlir/IR/Dominance.h"
#include "mlir/IR/Matchers.h"
#include "mlir/Interfaces/ControlFlowInterfaces.h"
#include <vector>

#define DEBUG_TYPE …

usingnamespacemlir;

namespace {
/// A helper struct for control-flow sinking.
class Sinker { … };
} // end anonymous namespace

bool Sinker::allUsersDominatedBy(Operation *op, Region *region) { … }

void Sinker::tryToSinkPredecessors(Operation *user, Region *region,
                                   std::vector<Operation *> &stack) { … }

void Sinker::sinkRegion(Region *region) { … }

size_t Sinker::sinkRegions(RegionRange regions) { … }

size_t mlir::controlFlowSink(
    RegionRange regions, DominanceInfo &domInfo,
    function_ref<bool(Operation *, Region *)> shouldMoveIntoRegion,
    function_ref<void(Operation *, Region *)> moveIntoRegion) { … }

void mlir::getSinglyExecutedRegionsToSink(RegionBranchOpInterface branch,
                                          SmallVectorImpl<Region *> &regions) { … }