LLVM  10.0.0svn
LaneBitmask.h
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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/Printable.h"
36 
37 namespace llvm {
38 
39  struct LaneBitmask {
40  // When changing the underlying type, change the format string as well.
41  using Type = unsigned;
42  enum : unsigned { BitWidth = 8*sizeof(Type) };
43  constexpr static const char *const FormatStr = "%08X";
44 
45  constexpr LaneBitmask() = default;
46  explicit constexpr LaneBitmask(Type V) : Mask(V) {}
47 
48  constexpr bool operator== (LaneBitmask M) const { return Mask == M.Mask; }
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 none() const { return Mask == 0; }
52  constexpr bool any() const { return Mask != 0; }
53  constexpr bool all() const { return ~Mask == 0; }
54 
55  constexpr LaneBitmask operator~() const {
56  return LaneBitmask(~Mask);
57  }
58  constexpr LaneBitmask operator|(LaneBitmask M) const {
59  return LaneBitmask(Mask | M.Mask);
60  }
61  constexpr LaneBitmask operator&(LaneBitmask M) const {
62  return LaneBitmask(Mask & M.Mask);
63  }
65  Mask |= M.Mask;
66  return *this;
67  }
69  Mask &= M.Mask;
70  return *this;
71  }
72 
73  constexpr Type getAsInteger() const { return Mask; }
74 
75  unsigned getNumLanes() const {
76  return countPopulation(Mask);
77  }
78  unsigned getHighestLane() const {
79  return Log2_32(Mask);
80  }
81 
82  static constexpr LaneBitmask getNone() { return LaneBitmask(0); }
83  static constexpr LaneBitmask getAll() { return ~LaneBitmask(0); }
84  static constexpr LaneBitmask getLane(unsigned Lane) {
85  return LaneBitmask(Type(1) << Lane);
86  }
87 
88  private:
89  Type Mask = 0;
90  };
91 
92  /// Create Printable object to print LaneBitmasks on a \ref raw_ostream.
93  inline Printable PrintLaneMask(LaneBitmask LaneMask) {
94  return Printable([LaneMask](raw_ostream &OS) {
95  OS << format(LaneBitmask::FormatStr, LaneMask.getAsInteger());
96  });
97  }
98 
99 } // end namespace llvm
100 
101 #endif // LLVM_MC_LANEBITMASK_H
unsigned getNumLanes() const
Definition: LaneBitmask.h:75
This class represents lattice values for constants.
Definition: AllocatorList.h:23
format_object< Ts... > format(const char *Fmt, const Ts &... Vals)
These are helper functions used to produce formatted output.
Definition: Format.h:124
unsigned getHighestLane() const
Definition: LaneBitmask.h:78
constexpr bool operator!=(LaneBitmask M) const
Definition: LaneBitmask.h:49
Printable PrintLaneMask(LaneBitmask LaneMask)
Create Printable object to print LaneBitmasks on a raw_ostream.
Definition: LaneBitmask.h:93
static constexpr LaneBitmask getAll()
Definition: LaneBitmask.h:83
static constexpr LaneBitmask getNone()
Definition: LaneBitmask.h:82
constexpr LaneBitmask operator~() const
Definition: LaneBitmask.h:55
constexpr LaneBitmask operator|(LaneBitmask M) const
Definition: LaneBitmask.h:58
static constexpr const char *const FormatStr
Definition: LaneBitmask.h:43
constexpr LaneBitmask()=default
static constexpr LaneBitmask getLane(unsigned Lane)
Definition: LaneBitmask.h:84
LaneBitmask & operator|=(LaneBitmask M)
Definition: LaneBitmask.h:64
constexpr bool none() const
Definition: LaneBitmask.h:51
constexpr LaneBitmask operator &(LaneBitmask M) const
Definition: LaneBitmask.h:61
constexpr bool all() const
Definition: LaneBitmask.h:53
constexpr Type getAsInteger() const
Definition: LaneBitmask.h:73
unsigned countPopulation(T Value)
Count the number of set bits in a value.
Definition: MathExtras.h:519
unsigned Log2_32(uint32_t Value)
Return the floor log base 2 of the specified value, -1 if the value is zero.
Definition: MathExtras.h:538
constexpr bool any() const
Definition: LaneBitmask.h:52
LaneBitmask & operator &=(LaneBitmask M)
Definition: LaneBitmask.h:68
constexpr bool operator<(LaneBitmask M) const
Definition: LaneBitmask.h:50
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:45
constexpr bool operator==(LaneBitmask M) const
Definition: LaneBitmask.h:48
constexpr LaneBitmask(Type V)
Definition: LaneBitmask.h:46
Simple wrapper around std::function<void(raw_ostream&)>.
Definition: Printable.h:37