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_REMOVE_SELECTION_REDUCTION_OPPORTUNITY_FINDER_H_
16 #define SOURCE_REDUCE_REMOVE_SELECTION_REDUCTION_OPPORTUNITY_FINDER_H_
17 
18 #include "source/reduce/reduction_opportunity_finder.h"
19 
20 namespace spvtools {
21 namespace reduce {
22 
23 // A finder for opportunities for removing a selection construct by simply
24 // removing the OpSelectionMerge instruction; thus, the selections must have
25 // already been simplified to a point where they can be trivially removed.
26 class RemoveSelectionReductionOpportunityFinder
27     : public ReductionOpportunityFinder {
28  public:
29   RemoveSelectionReductionOpportunityFinder() = default;
30 
31   ~RemoveSelectionReductionOpportunityFinder() override = default;
32 
33   std::string GetName() const final;
34 
35   std::vector<std::unique_ptr<ReductionOpportunity>> GetAvailableOpportunities(
36       opt::IRContext* context, uint32_t target_function) const final;
37 
38   // Returns true if the OpSelectionMerge instruction |merge_instruction| in
39   // block |header_block| can be removed.
40   static bool CanOpSelectionMergeBeRemoved(
41       opt::IRContext* context, const opt::BasicBlock& header_block,
42       opt::Instruction* merge_instruction,
43       std::unordered_set<uint32_t> merge_and_continue_blocks_from_loops);
44 };
45 
46 }  // namespace reduce
47 }  // namespace spvtools
48 
49 #endif  // SOURCE_REDUCE_REMOVE_SELECTION_REDUCTION_OPPORTUNITY_FINDER_H_
50