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https://github.com/KhronosGroup/SPIRV-Tools
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5ea7099374
Implements the following simplifications: (a - b) + b => a (a * b) + (a * c) => a * (b + c) Also adds logic to simplification to handle rules that create new operations that might need simplification, such as the second rule above. Only perform the second simplification if the multiplies have the add as their only use. Otherwise this is a deoptimization of size and performance.
59 lines
2.1 KiB
C++
59 lines
2.1 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_SIMPLIFICATION_PASS_H_
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#define SOURCE_OPT_SIMPLIFICATION_PASS_H_
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#include "source/opt/function.h"
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#include "source/opt/ir_context.h"
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#include "source/opt/pass.h"
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namespace spvtools {
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namespace opt {
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// See optimizer.hpp for documentation.
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class SimplificationPass : public Pass {
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public:
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const char* name() const override { return "simplify-instructions"; }
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Status Process() override;
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IRContext::Analysis GetPreservedAnalyses() override {
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return IRContext::kAnalysisDefUse |
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IRContext::kAnalysisInstrToBlockMapping |
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IRContext::kAnalysisDecorations | IRContext::kAnalysisCombinators |
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IRContext::kAnalysisCFG | IRContext::kAnalysisDominatorAnalysis |
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IRContext::kAnalysisNameMap | IRContext::kAnalysisConstants |
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IRContext::kAnalysisTypes;
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}
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private:
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// Returns true if the module was changed. The simplifier is called on every
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// instruction in |function| until nothing else in the function can be
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// simplified.
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bool SimplifyFunction(Function* function);
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// FactorAddMul can create |folded_inst| Mul of new Add. If Mul, push any Add
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// operand not in |seen_inst| into |worklist|. This is heavily restricted to
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// improve compile time but can be expanded for future simplifications which
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// simiarly create new operations.
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void AddNewOperands(Instruction* folded_inst,
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std::unordered_set<Instruction*>* inst_seen,
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std::vector<Instruction*>* work_list);
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};
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} // namespace opt
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} // namespace spvtools
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#endif // SOURCE_OPT_SIMPLIFICATION_PASS_H_
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