wehub-resource-sync
64 lines
2.7 KiB
C++
64 lines
2.7 KiB
C++
// Copyright (c) 2024 CINN Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/**
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* This file implements the strategy to remove the unnecessary schedule_block.
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*/
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#pragma once
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#include <vector>
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#include "paddle/cinn/common/common.h"
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#include "paddle/cinn/ir/ir.h"
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namespace cinn {
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namespace optim {
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/**
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*
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* This pass eliminates dead schedule blocks (those that do not affect the final
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* program output).
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*
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* This pass is applicable in scenarios where there are redundant computations
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* or store operations in the program. For example, certain schedule blocks may
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* not influence the final output or may be completely unused. This commonly
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* occurs in deeply nested loops where some sub-blocks are executed, but their
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* results are never used, leading to wasted computation. The goal of this pass
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* is to analyze the dependencies and data flow of schedule blocks to identify
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* and remove those that are unnecessary, simplifying the code and improving
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* execution efficiency.
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*
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* When applied, this pass will perform the following modifications to the IR:
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* 1. The IR will be scanned for schedule blocks that do not influence the final
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* output. These blocks will be marked as dead schedule blocks.
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* 2. Dead schedule blocks will be removed from the IR, eliminating unnecessary
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* computations. Specifically, in loops and conditional branches, any redundant
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* schedule blocks will be removed.
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* 3. While removing dead schedule blocks, other valid blocks in the IR will
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* remain unaffected, ensuring the correctness of the program.
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* 4. The final IR will be simplified, containing only the relevant computations
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* that contribute to the output, resulting in more efficient execution.
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*
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* Performance impact: This pass addresses performance issues by removing
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* unnecessary computations, potentially improving program execution efficiency,
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* especially when there are large amounts of unused computations. By
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* eliminating dead schedule blocks, execution time and memory consumption can
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* be reduced.
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*
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*/
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void EliminateDeadScheduleBlock(Expr* e,
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const std::vector<std::string>& output_names);
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} // namespace optim
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} // namespace cinn
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