| 1 | //===- LoopInvariantCodeMotion.cpp - Code to perform loop fusion-----------===// |
|---|---|
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | // |
| 9 | // This file implements loop invariant code motion. |
| 10 | // |
| 11 | //===----------------------------------------------------------------------===// |
| 12 | |
| 13 | #include "mlir/Transforms/Passes.h" |
| 14 | |
| 15 | #include "mlir/IR/PatternMatch.h" |
| 16 | #include "mlir/Interfaces/LoopLikeInterface.h" |
| 17 | #include "mlir/Transforms/LoopInvariantCodeMotionUtils.h" |
| 18 | |
| 19 | namespace mlir { |
| 20 | #define GEN_PASS_DEF_LOOPINVARIANTCODEMOTION |
| 21 | #define GEN_PASS_DEF_LOOPINVARIANTSUBSETHOISTING |
| 22 | #include "mlir/Transforms/Passes.h.inc" |
| 23 | } // namespace mlir |
| 24 | |
| 25 | using namespace mlir; |
| 26 | |
| 27 | namespace { |
| 28 | /// Loop invariant code motion (LICM) pass. |
| 29 | struct LoopInvariantCodeMotion |
| 30 | : public impl::LoopInvariantCodeMotionBase<LoopInvariantCodeMotion> { |
| 31 | void runOnOperation() override; |
| 32 | }; |
| 33 | |
| 34 | struct LoopInvariantSubsetHoisting |
| 35 | : public impl::LoopInvariantSubsetHoistingBase< |
| 36 | LoopInvariantSubsetHoisting> { |
| 37 | void runOnOperation() override; |
| 38 | }; |
| 39 | } // namespace |
| 40 | |
| 41 | void LoopInvariantCodeMotion::runOnOperation() { |
| 42 | // Walk through all loops in a function in innermost-loop-first order. This |
| 43 | // way, we first LICM from the inner loop, and place the ops in |
| 44 | // the outer loop, which in turn can be further LICM'ed. |
| 45 | getOperation()->walk( |
| 46 | callback: [&](LoopLikeOpInterface loopLike) { moveLoopInvariantCode(loopLike); }); |
| 47 | } |
| 48 | |
| 49 | void LoopInvariantSubsetHoisting::runOnOperation() { |
| 50 | IRRewriter rewriter(getOperation()->getContext()); |
| 51 | // Walk through all loops in a function in innermost-loop-first order. This |
| 52 | // way, we first hoist from the inner loop, and place the ops in the outer |
| 53 | // loop, which in turn can be further hoisted from. |
| 54 | getOperation()->walk(callback: [&](LoopLikeOpInterface loopLike) { |
| 55 | (void)hoistLoopInvariantSubsets(rewriter, loopLike); |
| 56 | }); |
| 57 | } |
| 58 | |
| 59 | std::unique_ptr<Pass> mlir::createLoopInvariantCodeMotionPass() { |
| 60 | return std::make_unique<LoopInvariantCodeMotion>(); |
| 61 | } |
| 62 | |
| 63 | std::unique_ptr<Pass> mlir::createLoopInvariantSubsetHoistingPass() { |
| 64 | return std::make_unique<LoopInvariantSubsetHoisting>(); |
| 65 | } |
| 66 |