llvm/llvm/include/llvm/CodeGen/LiveIntervalUnion.h

//===- LiveIntervalUnion.h - Live interval union data struct ---*- C++ -*--===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// LiveIntervalUnion is a union of live segments across multiple live virtual
// registers. This may be used during coalescing to represent a congruence
// class, or during register allocation to model liveness of a physical
// register.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CODEGEN_LIVEINTERVALUNION_H
#define LLVM_CODEGEN_LIVEINTERVALUNION_H

#include "llvm/ADT/IntervalMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/LiveInterval.h"
#include "llvm/CodeGen/SlotIndexes.h"
#include <cassert>
#include <limits>

namespace llvm {

class raw_ostream;
class TargetRegisterInfo;

#ifndef NDEBUG
// forward declaration
template <unsigned Element> class SparseBitVector;

using LiveVirtRegBitSet = SparseBitVector<128>;
#endif

/// Union of live intervals that are strong candidates for coalescing into a
/// single register (either physical or virtual depending on the context).  We
/// expect the constituent live intervals to be disjoint, although we may
/// eventually make exceptions to handle value-based interference.
class LiveIntervalUnion { … };

} // end namespace llvm

#endif // LLVM_CODEGEN_LIVEINTERVALUNION_H