llvm/mlir/lib/Dialect/Affine/Transforms/AffineLoopInvariantCodeMotion.cpp

//===- AffineLoopInvariantCodeMotion.cpp - Code to perform loop fusion-----===//
//
// 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 loop invariant code motion.
//
//===----------------------------------------------------------------------===//

#include "mlir/Dialect/Affine/Passes.h"

#include "mlir/Analysis/SliceAnalysis.h"
#include "mlir/Dialect/Affine/Analysis/AffineAnalysis.h"
#include "mlir/Dialect/Affine/Analysis/AffineStructures.h"
#include "mlir/Dialect/Affine/Analysis/LoopAnalysis.h"
#include "mlir/Dialect/Affine/Analysis/Utils.h"
#include "mlir/Dialect/Affine/IR/AffineOps.h"
#include "mlir/Dialect/Affine/LoopUtils.h"
#include "mlir/Dialect/Affine/Utils.h"
#include "mlir/Dialect/Arith/IR/Arith.h"
#include "mlir/Dialect/Func/IR/FuncOps.h"
#include "mlir/IR/AffineExpr.h"
#include "mlir/IR/AffineMap.h"
#include "mlir/IR/Builders.h"
#include "mlir/IR/Matchers.h"
#include "mlir/Interfaces/SideEffectInterfaces.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"

namespace mlir {
namespace affine {
#define GEN_PASS_DEF_AFFINELOOPINVARIANTCODEMOTION
#include "mlir/Dialect/Affine/Passes.h.inc"
} // namespace affine
} // namespace mlir

#define DEBUG_TYPE …

usingnamespacemlir;
usingnamespacemlir::affine;

namespace {

/// Affine loop invariant code motion (LICM) pass.
/// TODO: The pass is missing zero-trip tests.
/// TODO: This code should be removed once the new LICM pass can handle its
///       uses.
struct LoopInvariantCodeMotion
    : public affine::impl::AffineLoopInvariantCodeMotionBase<
          LoopInvariantCodeMotion> { … };
} // namespace

static bool
checkInvarianceOfNestedIfOps(AffineIfOp ifOp, Value indVar, ValueRange iterArgs,
                             SmallPtrSetImpl<Operation *> &opsWithUsers,
                             SmallPtrSetImpl<Operation *> &opsToHoist);
static bool isOpLoopInvariant(Operation &op, Value indVar, ValueRange iterArgs,
                              SmallPtrSetImpl<Operation *> &opsWithUsers,
                              SmallPtrSetImpl<Operation *> &opsToHoist);

static bool
areAllOpsInTheBlockListInvariant(Region &blockList, Value indVar,
                                 ValueRange iterArgs,
                                 SmallPtrSetImpl<Operation *> &opsWithUsers,
                                 SmallPtrSetImpl<Operation *> &opsToHoist);

// Returns true if the individual op is loop invariant.
static bool isOpLoopInvariant(Operation &op, Value indVar, ValueRange iterArgs,
                              SmallPtrSetImpl<Operation *> &opsWithUsers,
                              SmallPtrSetImpl<Operation *> &opsToHoist) { … }

// Checks if all ops in a region (i.e. list of blocks) are loop invariant.
static bool
areAllOpsInTheBlockListInvariant(Region &blockList, Value indVar,
                                 ValueRange iterArgs,
                                 SmallPtrSetImpl<Operation *> &opsWithUsers,
                                 SmallPtrSetImpl<Operation *> &opsToHoist) { … }

// Returns true if the affine.if op can be hoisted.
static bool
checkInvarianceOfNestedIfOps(AffineIfOp ifOp, Value indVar, ValueRange iterArgs,
                             SmallPtrSetImpl<Operation *> &opsWithUsers,
                             SmallPtrSetImpl<Operation *> &opsToHoist) { … }

void LoopInvariantCodeMotion::runOnAffineForOp(AffineForOp forOp) { … }

void LoopInvariantCodeMotion::runOnOperation() { … }

std::unique_ptr<OperationPass<func::FuncOp>>
mlir::affine::createAffineLoopInvariantCodeMotionPass() { … }