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// Copyright 2022 The Tint Authors.
//
// 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 SRC_TINT_IR_SWITCH_H_
#define SRC_TINT_IR_SWITCH_H_
#include "src/tint/ir/control_instruction.h"
// Forward declarations
namespace tint::ir {
class Constant;
class MultiInBlock;
} // namespace tint::ir
namespace tint::ir {
/// Switch instruction.
///
/// ```
/// in
/// ┃
/// ╌╌╌╌╌╌╌╌┲━━━━━━━━━━━━━━╋━━━━━━━━━━━━━━┱╌╌╌╌╌╌╌╌
/// ▼ ▼ ▼
/// ┌────────┐ ┌────────┐ ┌────────┐
/// │ Case A │ │ Case B │ │ Case C │
/// └────────┘ └────────┘ └────────┘
/// ExitSwitch ┃ ExitSwitch ┃ ExitSwitch ┃
/// ┃ ▼ ┃
/// ┃ ┌────────────┐ ┃
/// ╌╌╌╌╌╌╌╌┺━━━━━━▶│ Merge │◀━━━━━━━┹╌╌╌╌╌╌╌╌
/// │ (optional) │
/// └────────────┘
/// ┃
/// ▼
/// out
/// ```
class Switch : public utils::Castable<Switch, ControlInstruction> {
public:
/// A case selector
struct CaseSelector {
/// @returns true if this is a default selector
bool IsDefault() { return val == nullptr; }
/// The selector value, or nullptr if this is the default selector
Constant* val = nullptr;
};
/// A case label in the struct
struct Case {
/// The case selector for this node
utils::Vector<CaseSelector, 4> selectors;
/// The start block for the case block.
ir::Block* start = nullptr;
/// @returns the case start target
ir::Block* Start() { return start; }
};
/// Constructor
/// @param cond the condition
/// @param m the merge block
explicit Switch(Value* cond, ir::MultiInBlock* m);
~Switch() override;
/// @returns the switch merge branch
ir::MultiInBlock* Merge() { return merge_; }
/// @returns the switch cases
utils::Vector<Case, 4>& Cases() { return cases_; }
/// @returns the branch arguments
utils::Slice<Value* const> Args() override { return {}; }
/// @returns the condition
Value* Condition() { return operands_[0]; }
private:
ir::MultiInBlock* merge_ = nullptr;
utils::Vector<Case, 4> cases_;
};
} // namespace tint::ir
#endif // SRC_TINT_IR_SWITCH_H_