// 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.

#include "source/opt/block_merge_pass.h"

#include "source/opt/block_merge_util.h"

#include "source/opt/ir_context.h"

namespace spvtools {

namespace opt {

bool BlockMergePass::MergeBlocks(Function* func) {

  bool modified = false;

  for (auto bi = func->begin(); bi != func->end();) {

    // Don't bother trying to merge unreachable blocks.

    if (context()->IsReachable(*bi) &&

        blockmergeutil::CanMergeWithSuccessor(context(), &*bi)) {

      blockmergeutil::MergeWithSuccessor(context(), func, bi);

      // Reprocess block.

      modified = true;

    } else {

      ++bi;

    }

  }

  return modified;

}

Pass::Status BlockMergePass::Process() {

  // Process all entry point functions.

  ProcessFunction pfn = [this](Function* fp) { return MergeBlocks(fp); };

  bool modified = context()->ProcessReachableCallTree(pfn);

  return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;

}

BlockMergePass::BlockMergePass() = default;

}  // namespace opt

}  // namespace spvtools