79 lines
2.7 KiB
C++
79 lines
2.7 KiB
C++
// Copyright (c) 2018 Google LLC.
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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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#ifndef SOURCE_OPT_LOOP_FISSION_H_
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#define SOURCE_OPT_LOOP_FISSION_H_
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#include <algorithm>
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#include <cstdint>
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#include <map>
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#include <utility>
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#include <vector>
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#include "source/opt/cfg.h"
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#include "source/opt/loop_dependence.h"
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#include "source/opt/loop_utils.h"
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#include "source/opt/module.h"
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#include "source/opt/pass.h"
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#include "source/opt/tree_iterator.h"
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namespace spvtools {
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namespace opt {
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class LoopFissionPass : public Pass {
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public:
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// Fuction used to determine if a given loop should be split. Takes register
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// pressure region for that loop as a parameter and returns true if the loop
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// should be split.
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using FissionCriteriaFunction =
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std::function<bool(const RegisterLiveness::RegionRegisterLiveness&)>;
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// Pass built with this constructor will split all loops regardless of
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// register pressure. Will not split loops more than once.
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LoopFissionPass();
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// Split the loop if the number of registers used in the loop exceeds
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// |register_threshold_to_split|. |split_multiple_times| flag determines
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// whether or not the pass should split loops after already splitting them
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// once.
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LoopFissionPass(size_t register_threshold_to_split,
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bool split_multiple_times = true);
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// Split loops whose register pressure meets the criteria of |functor|.
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LoopFissionPass(FissionCriteriaFunction functor,
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bool split_multiple_times = true)
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: split_criteria_(functor), split_multiple_times_(split_multiple_times) {}
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const char* name() const override { return "loop-fission"; }
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Pass::Status Process() override;
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// Checks if |loop| meets the register pressure criteria to be split.
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bool ShouldSplitLoop(const Loop& loop, IRContext* context);
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private:
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// Functor to run in ShouldSplitLoop to determine if the register pressure
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// criteria is met for splitting the loop.
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FissionCriteriaFunction split_criteria_;
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// Flag designating whether or not we should also split the result of
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// previously split loops if they meet the register presure criteria.
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bool split_multiple_times_;
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};
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} // namespace opt
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} // namespace spvtools
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#endif // SOURCE_OPT_LOOP_FISSION_H_
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