llvm/llvm/include/llvm/MC/LaneBitmask.h

//===- llvm/MC/LaneBitmask.h ------------------------------------*- 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// A common definition of LaneBitmask for use in TableGen and CodeGen.
///
/// A lane mask is a bitmask representing the covering of a register with
/// sub-registers.
///
/// This is typically used to track liveness at sub-register granularity.
/// Lane masks for sub-register indices are similar to register units for
/// physical registers. The individual bits in a lane mask can't be assigned
/// any specific meaning. They can be used to check if two sub-register
/// indices overlap.
///
/// Iff the target has a register such that:
///
///   getSubReg(Reg, A) overlaps getSubReg(Reg, B)
///
/// then:
///
///   (getSubRegIndexLaneMask(A) & getSubRegIndexLaneMask(B)) != 0

#ifndef LLVM_MC_LANEBITMASK_H
#define LLVM_MC_LANEBITMASK_H

#include "llvm/Support/Compiler.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Printable.h"
#include "llvm/Support/raw_ostream.h"

namespace llvm {

  struct LaneBitmask { … };

  /// Create Printable object to print LaneBitmasks on a \ref raw_ostream.
  inline Printable PrintLaneMask(LaneBitmask LaneMask) { … }

} // end namespace llvm

#endif // LLVM_MC_LANEBITMASK_H