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_OPT_LOOP_FUSION_PASS_H_ 16 #define SOURCE_OPT_LOOP_FUSION_PASS_H_ 17 18 #include "source/opt/pass.h" 19 20 namespace spvtools { 21 namespace opt { 22 23 // Implements a loop fusion pass. 24 // This pass will look for adjacent loops that are compatible and legal to be 25 // fused. It will fuse all such loops as long as the register usage for the 26 // fused loop stays under the threshold defined by |max_registers_per_loop|. 27 class LoopFusionPass : public Pass { 28 public: 29 explicit LoopFusionPass(size_t max_registers_per_loop) 30 : Pass(), max_registers_per_loop_(max_registers_per_loop) {} 31 32 const char* name() const override { return "loop-fusion"; } 33 34 // Processes the given |module|. Returns Status::Failure if errors occur when 35 // processing. Returns the corresponding Status::Success if processing is 36 // succesful to indicate whether changes have been made to the modue. 37 Status Process() override; 38 39 private: 40 // Fuse loops in |function| if compatible, legal and the fused loop won't use 41 // too many registers. 42 bool ProcessFunction(Function* function); 43 44 // The maximum number of registers a fused loop is allowed to use. 45 size_t max_registers_per_loop_; 46 }; 47 48 } // namespace opt 49 } // namespace spvtools 50 51 #endif // SOURCE_OPT_LOOP_FUSION_PASS_H_ 52
