| // Copyright (c) 2019 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. |
| |
| #include "source/reduce/remove_block_reduction_opportunity_finder.h" |
| |
| #include "source/reduce/remove_block_reduction_opportunity.h" |
| |
| namespace spvtools { |
| namespace reduce { |
| |
| using opt::Function; |
| using opt::IRContext; |
| using opt::Instruction; |
| |
| std::string RemoveBlockReductionOpportunityFinder::GetName() const { |
| return "RemoveBlockReductionOpportunityFinder"; |
| } |
| |
| std::vector<std::unique_ptr<ReductionOpportunity>> |
| RemoveBlockReductionOpportunityFinder::GetAvailableOpportunities( |
| IRContext* context) const { |
| std::vector<std::unique_ptr<ReductionOpportunity>> result; |
| |
| // Consider every block in every function. |
| for (auto& function : *context->module()) { |
| for (auto bi = function.begin(); bi != function.end(); ++bi) { |
| if (IsBlockValidOpportunity(context, function, bi)) { |
| result.push_back(spvtools::MakeUnique<RemoveBlockReductionOpportunity>( |
| &function, &*bi)); |
| } |
| } |
| } |
| return result; |
| } |
| |
| bool RemoveBlockReductionOpportunityFinder::IsBlockValidOpportunity( |
| IRContext* context, Function& function, Function::iterator& bi) { |
| assert(bi != function.end() && "Block iterator was out of bounds"); |
| |
| // Don't remove first block; we don't want to end up with no blocks. |
| if (bi == function.begin()) { |
| return false; |
| } |
| |
| // Don't remove blocks with references. |
| if (context->get_def_use_mgr()->NumUsers(bi->id()) > 0) { |
| return false; |
| } |
| |
| // Don't remove blocks whose instructions have outside references. |
| if (!BlockInstructionsHaveNoOutsideReferences(context, bi)) { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool RemoveBlockReductionOpportunityFinder:: |
| BlockInstructionsHaveNoOutsideReferences(IRContext* context, |
| const Function::iterator& bi) { |
| // Get all instructions in block. |
| std::unordered_set<uint32_t> instructions_in_block; |
| for (const Instruction& instruction : *bi) { |
| instructions_in_block.insert(instruction.unique_id()); |
| } |
| |
| // For each instruction... |
| for (const Instruction& instruction : *bi) { |
| // For each use of the instruction... |
| bool no_uses_outside_block = context->get_def_use_mgr()->WhileEachUser( |
| &instruction, [&instructions_in_block](Instruction* user) -> bool { |
| // If the use is in this block, continue (return true). Otherwise, we |
| // found an outside use; return false (and stop). |
| return instructions_in_block.find(user->unique_id()) != |
| instructions_in_block.end(); |
| }); |
| |
| if (!no_uses_outside_block) { |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| } // namespace reduce |
| } // namespace spvtools |