1 // Copyright (c) 2019 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_MERGE_BLOCKS_REDUCTION_OPPORTUNITY_H_ 16 #define SOURCE_REDUCE_MERGE_BLOCKS_REDUCTION_OPPORTUNITY_H_ 17 18 #include "source/opt/basic_block.h" 19 #include "source/opt/function.h" 20 #include "source/reduce/reduction_opportunity.h" 21 22 namespace spvtools { 23 namespace reduce { 24 25 // An opportunity to merge two blocks into one. 26 class MergeBlocksReductionOpportunity : public ReductionOpportunity { 27 public: 28 // Creates the opportunity to merge |block| with its successor, where |block| 29 // is inside |function|, and |context| is the enclosing IR context. 30 MergeBlocksReductionOpportunity(opt::IRContext* context, 31 opt::Function* function, 32 opt::BasicBlock* block); 33 34 bool PreconditionHolds() override; 35 36 protected: 37 void Apply() override; 38 39 private: 40 opt::IRContext* context_; 41 opt::Function* function_; 42 43 // Rather than holding on to the block that can be merged with its successor, 44 // we hold on to its successor. This is because the predecessor block might 45 // get merged with *its* predecessor, and so will no longer exist, while the 46 // successor will continue to exist until this opportunity gets applied. 47 opt::BasicBlock* successor_block_; 48 }; 49 50 } // namespace reduce 51 } // namespace spvtools 52 53 #endif // SOURCE_REDUCE_MERGE_BLOCKS_REDUCTION_OPPORTUNITY_H_ 54