// Copyright (c) 2017 The Khronos Group Inc.

// Copyright (c) 2017 Valve Corporation

// Copyright (c) 2017 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_BLOCK_MERGE_PASS_H_

#define SOURCE_OPT_BLOCK_MERGE_PASS_H_

#include <algorithm>

#include <map>

#include <queue>

#include <unordered_map>

#include <unordered_set>

#include <utility>

#include "source/opt/basic_block.h"

#include "source/opt/def_use_manager.h"

#include "source/opt/ir_context.h"

#include "source/opt/module.h"

#include "source/opt/pass.h"

namespace spvtools {

namespace opt {

// See optimizer.hpp for documentation.

class BlockMergePass : public Pass {

 public:

  BlockMergePass();

  const char* name() const override { return "merge-blocks"; }

  Status Process() override;

  IRContext::Analysis GetPreservedAnalyses() override {

    return IRContext::kAnalysisDefUse |

           IRContext::kAnalysisInstrToBlockMapping |

           IRContext::kAnalysisDecorations | IRContext::kAnalysisCombinators |

           IRContext::kAnalysisNameMap | IRContext::kAnalysisConstants |

           IRContext::kAnalysisTypes;

  }

 private:

  // Search |func| for blocks which have a single Branch to a block

  // with no other predecessors. Merge these blocks into a single block.

  bool MergeBlocks(Function* func);

};

}  // namespace opt

}  // namespace spvtools

#endif  // SOURCE_OPT_BLOCK_MERGE_PASS_H_