LLVM  6.0.0svn
LaneBitmask.h
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1 //===- llvm/MC/LaneBitmask.h ------------------------------------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 ///
10 /// \file
11 /// A common definition of LaneBitmask for use in TableGen and CodeGen.
12 ///
13 /// A lane mask is a bitmask representing the covering of a register with
14 /// sub-registers.
15 ///
16 /// This is typically used to track liveness at sub-register granularity.
17 /// Lane masks for sub-register indices are similar to register units for
18 /// physical registers. The individual bits in a lane mask can't be assigned
19 /// any specific meaning. They can be used to check if two sub-register
20 /// indices overlap.
21 ///
22 /// Iff the target has a register such that:
23 ///
24 /// getSubReg(Reg, A) overlaps getSubReg(Reg, B)
25 ///
26 /// then:
27 ///
28 /// (getSubRegIndexLaneMask(A) & getSubRegIndexLaneMask(B)) != 0
29 
30 #ifndef LLVM_MC_LANEBITMASK_H
31 #define LLVM_MC_LANEBITMASK_H
32 
33 #include "llvm/Support/Compiler.h"
34 #include "llvm/Support/Format.h"
35 #include "llvm/Support/Printable.h"
37 
38 namespace llvm {
39 
40  struct LaneBitmask {
41  // When changing the underlying type, change the format string as well.
42  using Type = unsigned;
43  enum : unsigned { BitWidth = 8*sizeof(Type) };
44  constexpr static const char *const FormatStr = "%08X";
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  }
66  Mask |= M.Mask;
67  return *this;
68  }
70  Mask &= M.Mask;
71  return *this;
72  }
73 
74  constexpr Type getAsInteger() const { return Mask; }
75 
76  unsigned getNumLanes() const {
77  return countPopulation(Mask);
78  }
79  unsigned getHighestLane() const {
80  return Log2_32(Mask);
81  }
82 
83  static LaneBitmask getNone() { return LaneBitmask(0); }
84  static LaneBitmask getAll() { return ~LaneBitmask(0); }
85  static LaneBitmask getLane(unsigned Lane) {
86  return LaneBitmask(Type(1) << Lane);
87  }
88 
89  private:
90  Type Mask = 0;
91  };
92 
93  /// Create Printable object to print LaneBitmasks on a \ref raw_ostream.
94  inline Printable PrintLaneMask(LaneBitmask LaneMask) {
95  return Printable([LaneMask](raw_ostream &OS) {
96  OS << format(LaneBitmask::FormatStr, LaneMask.getAsInteger());
97  });
98  }
99 
100 } // end namespace llvm
101 
102 #endif // LLVM_MC_LANEBITMASK_H
unsigned getNumLanes() const
Definition: LaneBitmask.h:76
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
static LaneBitmask getAll()
Definition: LaneBitmask.h:84
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:79
constexpr bool operator!=(LaneBitmask M) const
Definition: LaneBitmask.h:50
Printable PrintLaneMask(LaneBitmask LaneMask)
Create Printable object to print LaneBitmasks on a raw_ostream.
Definition: LaneBitmask.h:94
constexpr LaneBitmask operator~() const
Definition: LaneBitmask.h:56
constexpr LaneBitmask operator|(LaneBitmask M) const
Definition: LaneBitmask.h:59
static constexpr const char *const FormatStr
Definition: LaneBitmask.h:44
constexpr LaneBitmask()=default
LaneBitmask & operator|=(LaneBitmask M)
Definition: LaneBitmask.h:65
constexpr bool none() const
Definition: LaneBitmask.h:52
constexpr LaneBitmask operator &(LaneBitmask M) const
Definition: LaneBitmask.h:62
constexpr bool all() const
Definition: LaneBitmask.h:54
constexpr Type getAsInteger() const
Definition: LaneBitmask.h:74
unsigned countPopulation(T Value)
Count the number of set bits in a value.
Definition: MathExtras.h:512
static LaneBitmask getNone()
Definition: LaneBitmask.h:83
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:531
static LaneBitmask getLane(unsigned Lane)
Definition: LaneBitmask.h:85
constexpr bool any() const
Definition: LaneBitmask.h:53
LaneBitmask & operator &=(LaneBitmask M)
Definition: LaneBitmask.h:69
constexpr bool operator<(LaneBitmask M) const
Definition: LaneBitmask.h:51
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:44
constexpr bool operator==(LaneBitmask M) const
Definition: LaneBitmask.h:49
constexpr LaneBitmask(Type V)
Definition: LaneBitmask.h:47
Simple wrapper around std::function<void(raw_ostream&)>.
Definition: Printable.h:38