chromium/third_party/spirv-tools/src/source/opt/control_dependence.h

// Copyright (c) 2021 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.

#ifndef SOURCE_OPT_CONTROL_DEPENDENCE_H_
#define SOURCE_OPT_CONTROL_DEPENDENCE_H_

#include <algorithm>
#include <cstdint>
#include <functional>
#include <ostream>
#include <unordered_map>
#include <vector>

#include "source/opt/cfg.h"
#include "source/opt/dominator_analysis.h"

namespace spvtools {
namespace opt {

class ControlDependence { … };

// Prints |dep| to |os| in a human-readable way. For example,
//   1->2           (target_bb_id = branch_target_bb_id = 2)
//   3->4 through 5 (target_bb_id = 4, branch_target_bb_id = 5)
std::ostream& operator<<(std::ostream& os, const ControlDependence& dep);

// Represents the control dependence graph. A basic block is control dependent
// on another if the result of that block (e.g. the condition of a conditional
// branch) influences whether it is executed or not. More formally, a block A is
// control dependent on B iff:
// 1. there exists a path from A to the exit node that does *not* go through B
//    (i.e., A does not postdominate B), and
// 2. there exists a path B -> b_1 -> ... -> b_n -> A such that A post-dominates
//    all nodes b_i.
class ControlDependenceAnalysis { … };

}  // namespace opt
}  // namespace spvtools

#endif  // SOURCE_OPT_CONTROL_DEPENDENCE_H_