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// 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/simple_conditional_branch_to_branch_opportunity_finder.h"
#include "source/reduce/reduction_util.h"
#include "source/reduce/simple_conditional_branch_to_branch_reduction_opportunity.h"
namespace spvtools {
namespace reduce {
std::vector<std::unique_ptr<ReductionOpportunity>>
SimpleConditionalBranchToBranchOpportunityFinder::GetAvailableOpportunities(
opt::IRContext* context, uint32_t target_function) const {
std::vector<std::unique_ptr<ReductionOpportunity>> result;
// Consider every function.
for (auto* function : GetTargetFunctions(context, target_function)) {
// Consider every block in the function.
for (auto& block : *function) {
// The terminator must be SpvOpBranchConditional.
opt::Instruction* terminator = block.terminator();
if (terminator->opcode() != SpvOpBranchConditional) {
continue;
}
// It must not be a selection header, as these cannot be followed by
// OpBranch.
if (block.GetMergeInst() &&
block.GetMergeInst()->opcode() == SpvOpSelectionMerge) {
continue;
}
// The conditional branch must be simplified.
if (terminator->GetSingleWordInOperand(kTrueBranchOperandIndex) !=
terminator->GetSingleWordInOperand(kFalseBranchOperandIndex)) {
continue;
}
result.push_back(
MakeUnique<SimpleConditionalBranchToBranchReductionOpportunity>(
block.terminator()));
}
}
return result;
}
std::string SimpleConditionalBranchToBranchOpportunityFinder::GetName() const {
return "SimpleConditionalBranchToBranchOpportunityFinder";
}
} // namespace reduce
} // namespace spvtools