1//===- ConstantRange.h - Represent a range ----------------------*- 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// Represent a range of possible values that may occur when the program is run
11// for an integral value.  This keeps track of a lower and upper bound for the
12// constant, which MAY wrap around the end of the numeric range.  To do this, it
13// keeps track of a [lower, upper) bound, which specifies an interval just like
14// STL iterators.  When used with boolean values, the following are important
15// ranges: :
16//
17//  [F, F) = {}     = Empty set
18//  [T, F) = {T}
19//  [F, T) = {F}
20//  [T, T) = {F, T} = Full set
21//
22// The other integral ranges use min/max values for special range values. For
23// example, for 8-bit types, it uses:
24// [0, 0)     = {}       = Empty set
25// [255, 255) = {0..255} = Full Set
26//
27// Note that ConstantRange can be used to represent either signed or
28// unsigned ranges.
29//
30//===----------------------------------------------------------------------===//
31
32#ifndef LLVM_SUPPORT_CONSTANTRANGE_H
33#define LLVM_SUPPORT_CONSTANTRANGE_H
34
35#include "llvm/ADT/APInt.h"
36#include "llvm/Support/DataTypes.h"
37
38namespace llvm {
39
40/// ConstantRange - This class represents an range of values.
41///
42class ConstantRange {
43  APInt Lower, Upper;
44
45  // If we have move semantics, pass APInts by value and move them into place.
46  typedef APInt APIntMoveTy;
47
48public:
49  /// Initialize a full (the default) or empty set for the specified bit width.
50  ///
51  explicit ConstantRange(uint32_t BitWidth, bool isFullSet = true);
52
53  /// Initialize a range to hold the single specified value.
54  ///
55  ConstantRange(APIntMoveTy Value);
56
57  /// @brief Initialize a range of values explicitly. This will assert out if
58  /// Lower==Upper and Lower != Min or Max value for its type. It will also
59  /// assert out if the two APInt's are not the same bit width.
60  ConstantRange(APIntMoveTy Lower, APIntMoveTy Upper);
61
62  /// makeICmpRegion - Produce the smallest range that contains all values that
63  /// might satisfy the comparison specified by Pred when compared to any value
64  /// contained within Other.
65  ///
66  /// Solves for range X in 'for all x in X, there exists a y in Y such that
67  /// icmp op x, y is true'. Every value that might make the comparison true
68  /// is included in the resulting range.
69  static ConstantRange makeICmpRegion(unsigned Pred,
70                                      const ConstantRange &Other);
71
72  /// getLower - Return the lower value for this range...
73  ///
74  const APInt &getLower() const { return Lower; }
75
76  /// getUpper - Return the upper value for this range...
77  ///
78  const APInt &getUpper() const { return Upper; }
79
80  /// getBitWidth - get the bit width of this ConstantRange
81  ///
82  uint32_t getBitWidth() const { return Lower.getBitWidth(); }
83
84  /// isFullSet - Return true if this set contains all of the elements possible
85  /// for this data-type
86  ///
87  bool isFullSet() const;
88
89  /// isEmptySet - Return true if this set contains no members.
90  ///
91  bool isEmptySet() const;
92
93  /// isWrappedSet - Return true if this set wraps around the top of the range,
94  /// for example: [100, 8)
95  ///
96  bool isWrappedSet() const;
97
98  /// isSignWrappedSet - Return true if this set wraps around the INT_MIN of
99  /// its bitwidth, for example: i8 [120, 140).
100  ///
101  bool isSignWrappedSet() const;
102
103  /// contains - Return true if the specified value is in the set.
104  ///
105  bool contains(const APInt &Val) const;
106
107  /// contains - Return true if the other range is a subset of this one.
108  ///
109  bool contains(const ConstantRange &CR) const;
110
111  /// getSingleElement - If this set contains a single element, return it,
112  /// otherwise return null.
113  ///
114  const APInt *getSingleElement() const {
115    if (Upper == Lower + 1)
116      return &Lower;
117    return nullptr;
118  }
119
120  /// isSingleElement - Return true if this set contains exactly one member.
121  ///
122  bool isSingleElement() const { return getSingleElement() != nullptr; }
123
124  /// getSetSize - Return the number of elements in this set.
125  ///
126  APInt getSetSize() const;
127
128  /// getUnsignedMax - Return the largest unsigned value contained in the
129  /// ConstantRange.
130  ///
131  APInt getUnsignedMax() const;
132
133  /// getUnsignedMin - Return the smallest unsigned value contained in the
134  /// ConstantRange.
135  ///
136  APInt getUnsignedMin() const;
137
138  /// getSignedMax - Return the largest signed value contained in the
139  /// ConstantRange.
140  ///
141  APInt getSignedMax() const;
142
143  /// getSignedMin - Return the smallest signed value contained in the
144  /// ConstantRange.
145  ///
146  APInt getSignedMin() const;
147
148  /// operator== - Return true if this range is equal to another range.
149  ///
150  bool operator==(const ConstantRange &CR) const {
151    return Lower == CR.Lower && Upper == CR.Upper;
152  }
153  bool operator!=(const ConstantRange &CR) const {
154    return !operator==(CR);
155  }
156
157  /// subtract - Subtract the specified constant from the endpoints of this
158  /// constant range.
159  ConstantRange subtract(const APInt &CI) const;
160
161  /// \brief Subtract the specified range from this range (aka relative
162  /// complement of the sets).
163  ConstantRange difference(const ConstantRange &CR) const;
164
165  /// intersectWith - Return the range that results from the intersection of
166  /// this range with another range.  The resultant range is guaranteed to
167  /// include all elements contained in both input ranges, and to have the
168  /// smallest possible set size that does so.  Because there may be two
169  /// intersections with the same set size, A.intersectWith(B) might not
170  /// be equal to B.intersectWith(A).
171  ///
172  ConstantRange intersectWith(const ConstantRange &CR) const;
173
174  /// unionWith - Return the range that results from the union of this range
175  /// with another range.  The resultant range is guaranteed to include the
176  /// elements of both sets, but may contain more.  For example, [3, 9) union
177  /// [12,15) is [3, 15), which includes 9, 10, and 11, which were not included
178  /// in either set before.
179  ///
180  ConstantRange unionWith(const ConstantRange &CR) const;
181
182  /// zeroExtend - Return a new range in the specified integer type, which must
183  /// be strictly larger than the current type.  The returned range will
184  /// correspond to the possible range of values if the source range had been
185  /// zero extended to BitWidth.
186  ConstantRange zeroExtend(uint32_t BitWidth) const;
187
188  /// signExtend - Return a new range in the specified integer type, which must
189  /// be strictly larger than the current type.  The returned range will
190  /// correspond to the possible range of values if the source range had been
191  /// sign extended to BitWidth.
192  ConstantRange signExtend(uint32_t BitWidth) const;
193
194  /// truncate - Return a new range in the specified integer type, which must be
195  /// strictly smaller than the current type.  The returned range will
196  /// correspond to the possible range of values if the source range had been
197  /// truncated to the specified type.
198  ConstantRange truncate(uint32_t BitWidth) const;
199
200  /// zextOrTrunc - make this range have the bit width given by \p BitWidth. The
201  /// value is zero extended, truncated, or left alone to make it that width.
202  ConstantRange zextOrTrunc(uint32_t BitWidth) const;
203
204  /// sextOrTrunc - make this range have the bit width given by \p BitWidth. The
205  /// value is sign extended, truncated, or left alone to make it that width.
206  ConstantRange sextOrTrunc(uint32_t BitWidth) const;
207
208  /// add - Return a new range representing the possible values resulting
209  /// from an addition of a value in this range and a value in \p Other.
210  ConstantRange add(const ConstantRange &Other) const;
211
212  /// sub - Return a new range representing the possible values resulting
213  /// from a subtraction of a value in this range and a value in \p Other.
214  ConstantRange sub(const ConstantRange &Other) const;
215
216  /// multiply - Return a new range representing the possible values resulting
217  /// from a multiplication of a value in this range and a value in \p Other.
218  /// TODO: This isn't fully implemented yet.
219  ConstantRange multiply(const ConstantRange &Other) const;
220
221  /// smax - Return a new range representing the possible values resulting
222  /// from a signed maximum of a value in this range and a value in \p Other.
223  ConstantRange smax(const ConstantRange &Other) const;
224
225  /// umax - Return a new range representing the possible values resulting
226  /// from an unsigned maximum of a value in this range and a value in \p Other.
227  ConstantRange umax(const ConstantRange &Other) const;
228
229  /// udiv - Return a new range representing the possible values resulting
230  /// from an unsigned division of a value in this range and a value in
231  /// \p Other.
232  ConstantRange udiv(const ConstantRange &Other) const;
233
234  /// binaryAnd - return a new range representing the possible values resulting
235  /// from a binary-and of a value in this range by a value in \p Other.
236  ConstantRange binaryAnd(const ConstantRange &Other) const;
237
238  /// binaryOr - return a new range representing the possible values resulting
239  /// from a binary-or of a value in this range by a value in \p Other.
240  ConstantRange binaryOr(const ConstantRange &Other) const;
241
242  /// shl - Return a new range representing the possible values resulting
243  /// from a left shift of a value in this range by a value in \p Other.
244  /// TODO: This isn't fully implemented yet.
245  ConstantRange shl(const ConstantRange &Other) const;
246
247  /// lshr - Return a new range representing the possible values resulting
248  /// from a logical right shift of a value in this range and a value in
249  /// \p Other.
250  ConstantRange lshr(const ConstantRange &Other) const;
251
252  /// inverse - Return a new range that is the logical not of the current set.
253  ///
254  ConstantRange inverse() const;
255
256  /// print - Print out the bounds to a stream...
257  ///
258  void print(raw_ostream &OS) const;
259
260  /// dump - Allow printing from a debugger easily...
261  ///
262  void dump() const;
263};
264
265inline raw_ostream &operator<<(raw_ostream &OS, const ConstantRange &CR) {
266  CR.print(OS);
267  return OS;
268}
269
270} // End llvm namespace
271
272#endif
273