// Copyright (c) 2018 Google LLC

//

// 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_SIMPLIFICATION_PASS_H_

#define SOURCE_OPT_SIMPLIFICATION_PASS_H_

#include "source/opt/function.h"

#include "source/opt/ir_context.h"

#include "source/opt/pass.h"

namespace spvtools {

namespace opt {

// See optimizer.hpp for documentation.

class SimplificationPass : public Pass {

 public:

  const char* name() const override { return "simplify-instructions"; }

  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:

  // Returns true if the module was changed.  The simplifier is called on every

  // instruction in |function| until nothing else in the function can be

  // simplified.

  bool SimplifyFunction(Function* function);

  // FactorAddMul can create |folded_inst| Mul of new Add. If Mul, push any Add

  // operand not in |seen_inst| into |worklist|. This is heavily restricted to

  // improve compile time but can be expanded for future simplifications which

  // simiarly create new operations.

  void AddNewOperands(Instruction* folded_inst,

                      std::unordered_set<Instruction*>* inst_seen,

                      std::vector<Instruction*>* work_list);

};

}  // namespace opt

}  // namespace spvtools

#endif  // SOURCE_OPT_SIMPLIFICATION_PASS_H_