text: // 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_REDUCE_REMOVE_UNREFERENCED_INSTRUCTION_REDUCTION_PASS_H_
  #define SOURCE_REDUCE_REMOVE_UNREFERENCED_INSTRUCTION_REDUCTION_PASS_H_
  
  #include "reduction_pass.h"
  
  namespace spvtools {
  namespace reduce {
  
  // A reduction pass for removing non-control-flow instructions in blocks in
  // cases where the instruction's id is not referenced.  As well as making the
  // module smaller, removing an instruction that references particular ids may
  // create opportunities for subsequently removing the instructions that
  // generated those ids.
  class RemoveUnreferencedInstructionReductionPass : public ReductionPass {
   public:
    // Creates the reduction pass in the context of the given target environment
    // |target_env|
    explicit RemoveUnreferencedInstructionReductionPass(
        const spv_target_env target_env)
        : ReductionPass(target_env) {}
  
    ~RemoveUnreferencedInstructionReductionPass() override = default;
  
    std::string GetName() const final;
  
   protected:
    std::vector<std::unique_ptr<ReductionOpportunity>> GetAvailableOpportunities(
        opt::IRContext* context) const final;
  
   private:
  };
  
  }  // namespace reduce
  }  // namespace spvtools
  
  #endif  // SOURCE_REDUCE_REMOVE_UNREFERENCED_INSTRUCTION_REDUCTION_PASS_H_
  