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llvm-mirror/include/llvm/MC/LaneBitmask.h
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

102 lines
3.2 KiB
C++

//===- 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/Printable.h"
#include "llvm/Support/raw_ostream.h"
namespace llvm {
struct LaneBitmask {
// When changing the underlying type, change the format string as well.
using Type = unsigned;
enum : unsigned { BitWidth = 8*sizeof(Type) };
constexpr static const char *const FormatStr = "%08X";
constexpr LaneBitmask() = default;
explicit constexpr LaneBitmask(Type V) : Mask(V) {}
constexpr bool operator== (LaneBitmask M) const { return Mask == M.Mask; }
constexpr bool operator!= (LaneBitmask M) const { return Mask != M.Mask; }
constexpr bool operator< (LaneBitmask M) const { return Mask < M.Mask; }
constexpr bool none() const { return Mask == 0; }
constexpr bool any() const { return Mask != 0; }
constexpr bool all() const { return ~Mask == 0; }
constexpr LaneBitmask operator~() const {
return LaneBitmask(~Mask);
}
constexpr LaneBitmask operator|(LaneBitmask M) const {
return LaneBitmask(Mask | M.Mask);
}
constexpr LaneBitmask operator&(LaneBitmask M) const {
return LaneBitmask(Mask & M.Mask);
}
LaneBitmask &operator|=(LaneBitmask M) {
Mask |= M.Mask;
return *this;
}
LaneBitmask &operator&=(LaneBitmask M) {
Mask &= M.Mask;
return *this;
}
constexpr Type getAsInteger() const { return Mask; }
unsigned getNumLanes() const {
return countPopulation(Mask);
}
unsigned getHighestLane() const {
return Log2_32(Mask);
}
static constexpr LaneBitmask getNone() { return LaneBitmask(0); }
static constexpr LaneBitmask getAll() { return ~LaneBitmask(0); }
static constexpr LaneBitmask getLane(unsigned Lane) {
return LaneBitmask(Type(1) << Lane);
}
private:
Type Mask = 0;
};
/// Create Printable object to print LaneBitmasks on a \ref raw_ostream.
inline Printable PrintLaneMask(LaneBitmask LaneMask) {
return Printable([LaneMask](raw_ostream &OS) {
OS << format(LaneBitmask::FormatStr, LaneMask.getAsInteger());
});
}
} // end namespace llvm
#endif // LLVM_MC_LANEBITMASK_H