1 // Copyright (c) 2018 Google Inc. 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 #include "remove_unreferenced_instruction_reduction_pass.h" 16 #include "remove_instruction_reduction_opportunity.h" 17 #include "source/opcode.h" 18 #include "source/opt/instruction.h" 19 20 namespace spvtools { 21 namespace reduce { 22 23 using namespace opt; 24 25 std::vector<std::unique_ptr<ReductionOpportunity>> 26 RemoveUnreferencedInstructionReductionPass::GetAvailableOpportunities( 27 opt::IRContext* context) const { 28 std::vector<std::unique_ptr<ReductionOpportunity>> result; 29 30 for (auto& function : *context->module()) { 31 for (auto& block : function) { 32 for (auto& inst : block) { 33 if (context->get_def_use_mgr()->NumUses(&inst) > 0) { 34 continue; 35 } 36 if (spvOpcodeIsBlockTerminator(inst.opcode()) || 37 inst.opcode() == SpvOpSelectionMerge || 38 inst.opcode() == SpvOpLoopMerge) { 39 // In this reduction pass we do not want to affect static control 40 // flow. 41 continue; 42 } 43 // Given that we're in a block, we should only get here if the 44 // instruction is not directly related to control flow; i.e., it's 45 // some straightforward instruction with an unused result, like an 46 // arithmetic operation or function call. 47 result.push_back( 48 MakeUnique<RemoveInstructionReductionOpportunity>(&inst)); 49 } 50 } 51 } 52 return result; 53 } 54 55 std::string RemoveUnreferencedInstructionReductionPass::GetName() const { 56 return "RemoveUnreferencedInstructionReductionPass"; 57 } 58 59 } // namespace reduce 60 } // namespace spvtools 61
