| 1 | //===- LoopInvariantCodeMotion.cpp - Code to perform loop fusion-----------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | // |
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| 9 | // This file implements loop invariant code motion. |
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| 10 | // |
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| 11 | //===----------------------------------------------------------------------===// |
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| 12 | |
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| 13 | #include "mlir/Transforms/Passes.h" |
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| 14 | |
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| 15 | #include "mlir/IR/PatternMatch.h" |
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| 16 | #include "mlir/Interfaces/LoopLikeInterface.h" |
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| 17 | #include "mlir/Interfaces/SideEffectInterfaces.h" |
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| 18 | #include "mlir/Transforms/LoopInvariantCodeMotionUtils.h" |
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| 19 | |
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| 20 | namespace mlir { |
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| 21 | #define GEN_PASS_DEF_LOOPINVARIANTCODEMOTION |
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| 22 | #define GEN_PASS_DEF_LOOPINVARIANTSUBSETHOISTING |
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| 23 | #include "mlir/Transforms/Passes.h.inc" |
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| 24 | } // namespace mlir |
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| 25 | |
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| 26 | using namespace mlir; |
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| 27 | |
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| 28 | namespace { |
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| 29 | /// Loop invariant code motion (LICM) pass. |
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| 30 | struct LoopInvariantCodeMotion |
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| 31 | : public impl::LoopInvariantCodeMotionBase<LoopInvariantCodeMotion> { |
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| 32 | void runOnOperation() override; |
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| 33 | }; |
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| 34 | |
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| 35 | struct LoopInvariantSubsetHoisting |
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| 36 | : public impl::LoopInvariantSubsetHoistingBase< |
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| 37 | LoopInvariantSubsetHoisting> { |
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| 38 | void runOnOperation() override; |
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| 39 | }; |
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| 40 | } // namespace |
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| 41 | |
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| 42 | void LoopInvariantCodeMotion::runOnOperation() { |
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| 43 | // Walk through all loops in a function in innermost-loop-first order. This |
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| 44 | // way, we first LICM from the inner loop, and place the ops in |
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| 45 | // the outer loop, which in turn can be further LICM'ed. |
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| 46 | getOperation()->walk( |
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| 47 | [&](LoopLikeOpInterface loopLike) { moveLoopInvariantCode(loopLike); }); |
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| 48 | } |
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| 49 | |
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| 50 | void LoopInvariantSubsetHoisting::runOnOperation() { |
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| 51 | IRRewriter rewriter(getOperation()->getContext()); |
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| 52 | // Walk through all loops in a function in innermost-loop-first order. This |
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| 53 | // way, we first hoist from the inner loop, and place the ops in the outer |
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| 54 | // loop, which in turn can be further hoisted from. |
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| 55 | getOperation()->walk([&](LoopLikeOpInterface loopLike) { |
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| 56 | (void)hoistLoopInvariantSubsets(rewriter, loopLike); |
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| 57 | }); |
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| 58 | } |
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| 59 | |
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| 60 | std::unique_ptr<Pass> mlir::createLoopInvariantCodeMotionPass() { |
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| 61 | return std::make_unique<LoopInvariantCodeMotion>(); |
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| 62 | } |
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| 63 | |
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| 64 | std::unique_ptr<Pass> mlir::createLoopInvariantSubsetHoistingPass() { |
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| 65 | return std::make_unique<LoopInvariantSubsetHoisting>(); |
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| 66 | } |
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| 67 | |
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