1//===- llvm/MC/LaneBitmask.h ------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8///
9/// \file
10/// A common definition of LaneBitmask for use in TableGen and CodeGen.
11///
12/// A lane mask is a bitmask representing the covering of a register with
13/// sub-registers.
14///
15/// This is typically used to track liveness at sub-register granularity.
16/// Lane masks for sub-register indices are similar to register units for
17/// physical registers. The individual bits in a lane mask can't be assigned
18/// any specific meaning. They can be used to check if two sub-register
19/// indices overlap.
20///
21/// Iff the target has a register such that:
22///
23/// getSubReg(Reg, A) overlaps getSubReg(Reg, B)
24///
25/// then:
26///
27/// (getSubRegIndexLaneMask(A) & getSubRegIndexLaneMask(B)) != 0
28
29#ifndef LLVM_MC_LANEBITMASK_H
30#define LLVM_MC_LANEBITMASK_H
31
32#include "llvm/Support/Compiler.h"
33#include "llvm/Support/Format.h"
34#include "llvm/Support/MathExtras.h"
35#include "llvm/Support/Printable.h"
36#include "llvm/Support/raw_ostream.h"
37
38namespace llvm {
39
40 struct LaneBitmask {
41 // When changing the underlying type, change the format string as well.
42 using Type = uint64_t;
43 enum : unsigned { BitWidth = 8*sizeof(Type) };
44 constexpr static const char *const FormatStr = "%016llX";
45
46 constexpr LaneBitmask() = default;
47 explicit constexpr LaneBitmask(Type V) : Mask(V) {}
48
49 constexpr bool operator== (LaneBitmask M) const { return Mask == M.Mask; }
50 constexpr bool operator!= (LaneBitmask M) const { return Mask != M.Mask; }
51 constexpr bool operator< (LaneBitmask M) const { return Mask < M.Mask; }
52 constexpr bool none() const { return Mask == 0; }
53 constexpr bool any() const { return Mask != 0; }
54 constexpr bool all() const { return ~Mask == 0; }
55
56 constexpr LaneBitmask operator~() const {
57 return LaneBitmask(~Mask);
58 }
59 constexpr LaneBitmask operator|(LaneBitmask M) const {
60 return LaneBitmask(Mask | M.Mask);
61 }
62 constexpr LaneBitmask operator&(LaneBitmask M) const {
63 return LaneBitmask(Mask & M.Mask);
64 }
65 LaneBitmask &operator|=(LaneBitmask M) {
66 Mask |= M.Mask;
67 return *this;
68 }
69 LaneBitmask &operator&=(LaneBitmask M) {
70 Mask &= M.Mask;
71 return *this;
72 }
73
74 constexpr Type getAsInteger() const { return Mask; }
75
76 unsigned getNumLanes() const { return llvm::popcount(Value: Mask); }
77 unsigned getHighestLane() const {
78 return Log2_64(Value: Mask);
79 }
80
81 static constexpr LaneBitmask getNone() { return LaneBitmask(0); }
82 static constexpr LaneBitmask getAll() { return ~LaneBitmask(0); }
83 static constexpr LaneBitmask getLane(unsigned Lane) {
84 return LaneBitmask(Type(1) << Lane);
85 }
86
87 private:
88 Type Mask = 0;
89 };
90
91 /// Create Printable object to print LaneBitmasks on a \ref raw_ostream.
92 inline Printable PrintLaneMask(LaneBitmask LaneMask) {
93 return Printable([LaneMask](raw_ostream &OS) {
94 OS << format(Fmt: LaneBitmask::FormatStr, Vals: LaneMask.getAsInteger());
95 });
96 }
97
98} // end namespace llvm
99
100#endif // LLVM_MC_LANEBITMASK_H
101

source code of llvm/include/llvm/MC/LaneBitmask.h