1 // Copyright (c) 2018 Google LLC 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef SOURCE_REDUCE_CUT_LOOP_REDUCTION_PASS_H_ 16 #define SOURCE_REDUCE_CUT_LOOP_REDUCTION_PASS_H_ 17 18 #include "reduction_pass.h" 19 20 namespace spvtools { 21 namespace reduce { 22 23 // Turns structured loops into selections, generalizing from a human-writable 24 // language the idea of turning a loop: 25 // 26 // while (c) { 27 // body; 28 // } 29 // 30 // into: 31 // 32 // if (c) { 33 // body; 34 // } 35 // 36 // The pass results in continue constructs of transformed loops becoming 37 // unreachable; another pass for eliminating blocks may end up being able to 38 // remove them. 39 class StructuredLoopToSelectionReductionPass : public ReductionPass { 40 public: 41 // Creates the reduction pass in the context of the given target environment 42 // |target_env| StructuredLoopToSelectionReductionPass(const spv_target_env target_env)43 explicit StructuredLoopToSelectionReductionPass( 44 const spv_target_env target_env) 45 : ReductionPass(target_env) {} 46 47 ~StructuredLoopToSelectionReductionPass() override = default; 48 49 // The name of this pass. 50 std::string GetName() const final; 51 52 protected: 53 // Finds all opportunities for transforming a structured loop to a selection 54 // in the given module. 55 std::vector<std::unique_ptr<ReductionOpportunity>> GetAvailableOpportunities( 56 opt::IRContext* context) const final; 57 58 private: 59 }; 60 61 } // namespace reduce 62 } // namespace spvtools 63 64 #endif // SOURCE_REDUCE_CUT_LOOP_REDUCTION_PASS_H_ 65