2164a449dc
Add a loop-invariant subset hoisting pass to `mlir/Interfaces`. This pass hoist loop-invariant tensor subsets (subset extraction and subset insertion ops) from loop-like ops. Extraction ops are moved before the loop. Insertion ops are moved after the loop. The loop body operates on newly added region iter_args (one per extraction-insertion pair). This new pass will be improved in subsequent commits (to support more cases/ops) and will eventually replace `Linalg/Transforms/SubsetHoisting.cpp`. In contrast to the existing Linalg subset hoisting, the new pass is op interface-based (`SubsetOpInterface` and `LoopLikeOpInterface`).
65 lines
2.2 KiB
C++
65 lines
2.2 KiB
C++
//===- LoopInvariantCodeMotion.cpp - Code to perform loop fusion-----------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements loop invariant code motion.
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//
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//===----------------------------------------------------------------------===//
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#include "mlir/Transforms/Passes.h"
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#include "mlir/Interfaces/LoopLikeInterface.h"
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#include "mlir/Interfaces/SideEffectInterfaces.h"
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#include "mlir/Transforms/LoopInvariantCodeMotionUtils.h"
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namespace mlir {
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#define GEN_PASS_DEF_LOOPINVARIANTCODEMOTION
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#define GEN_PASS_DEF_LOOPINVARIANTSUBSETHOISTING
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#include "mlir/Transforms/Passes.h.inc"
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} // namespace mlir
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using namespace mlir;
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namespace {
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/// Loop invariant code motion (LICM) pass.
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struct LoopInvariantCodeMotion
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: public impl::LoopInvariantCodeMotionBase<LoopInvariantCodeMotion> {
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void runOnOperation() override;
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};
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struct LoopInvariantSubsetHoisting
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: public impl::LoopInvariantSubsetHoistingBase<
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LoopInvariantSubsetHoisting> {
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void runOnOperation() override;
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};
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} // namespace
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void LoopInvariantCodeMotion::runOnOperation() {
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// Walk through all loops in a function in innermost-loop-first order. This
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// way, we first LICM from the inner loop, and place the ops in
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// the outer loop, which in turn can be further LICM'ed.
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getOperation()->walk(
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[&](LoopLikeOpInterface loopLike) { moveLoopInvariantCode(loopLike); });
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}
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void LoopInvariantSubsetHoisting::runOnOperation() {
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// Walk through all loops in a function in innermost-loop-first order. This
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// way, we first hoist from the inner loop, and place the ops in the outer
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// loop, which in turn can be further hoisted from.
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getOperation()->walk([&](LoopLikeOpInterface loopLike) {
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(void)hoistLoopInvariantSubsets(loopLike);
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});
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}
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std::unique_ptr<Pass> mlir::createLoopInvariantCodeMotionPass() {
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return std::make_unique<LoopInvariantCodeMotion>();
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}
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std::unique_ptr<Pass> mlir::createLoopInvariantSubsetHoistingPass() {
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return std::make_unique<LoopInvariantSubsetHoisting>();
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}
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