SPIRV-Tools/source/opt/dead_insert_elim_pass.h

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// Copyright (c) 2018 The Khronos Group Inc.
// Copyright (c) 2018 Valve Corporation
// Copyright (c) 2018 LunarG Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef SOURCE_OPT_DEAD_INSERT_ELIM_PASS_H_
#define SOURCE_OPT_DEAD_INSERT_ELIM_PASS_H_
#include <algorithm>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
#include "source/opt/basic_block.h"
#include "source/opt/def_use_manager.h"
#include "source/opt/ir_context.h"
#include "source/opt/mem_pass.h"
#include "source/opt/module.h"
namespace spvtools {
namespace opt {
// See optimizer.hpp for documentation.
class DeadInsertElimPass : public MemPass {
public:
DeadInsertElimPass() = default;
const char* name() const override { return "eliminate-dead-inserts"; }
Status Process() override;
IRContext::Analysis GetPreservedAnalyses() override {
return IRContext::kAnalysisDefUse |
IRContext::kAnalysisInstrToBlockMapping |
IRContext::kAnalysisDecorations | IRContext::kAnalysisCombinators |
IRContext::kAnalysisCFG | IRContext::kAnalysisDominatorAnalysis |
IRContext::kAnalysisNameMap | IRContext::kAnalysisConstants |
IRContext::kAnalysisTypes;
}
private:
// Return the number of subcomponents in the composite type |typeId|.
// Return 0 if not a composite type or number of components is not a
// 32-bit constant.
uint32_t NumComponents(Instruction* typeInst);
// Mark all inserts in instruction chain ending at |insertChain| with
// indices that intersect with extract indices |extIndices| starting with
// index at |extOffset|. Chains are composed solely of Inserts and Phis.
// Mark all inserts in chain if |extIndices| is nullptr.
void MarkInsertChain(Instruction* insertChain,
std::vector<uint32_t>* extIndices, uint32_t extOffset,
std::unordered_set<uint32_t>* visited_phis);
// Perform EliminateDeadInsertsOnePass(|func|) until no modification is
// made. Return true if modified.
bool EliminateDeadInserts(Function* func);
// DCE all dead struct, matrix and vector inserts in |func|. An insert is
// dead if the value it inserts is never used. Replace any reference to the
// insert with its original composite. Return true if modified. Dead inserts
// in dependence cycles are not currently eliminated. Dead inserts into
// arrays are not currently eliminated.
bool EliminateDeadInsertsOnePass(Function* func);
// Return true if all extensions in this module are allowed by this pass.
bool AllExtensionsSupported() const;
// Live inserts
std::unordered_set<uint32_t> liveInserts_;
// Visited phis as insert chain is traversed; used to avoid infinite loop
std::unordered_map<uint32_t, bool> visitedPhis_;
};
} // namespace opt
} // namespace spvtools
#endif // SOURCE_OPT_DEAD_INSERT_ELIM_PASS_H_