1 //===-- llvm/Support/ConstantRange.h - Represent a range --------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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
17 // [F, F) = {} = Empty set
20 // [T, T) = {F, T} = Full set
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
27 // Note that ConstantRange always keeps unsigned values.
28 //===----------------------------------------------------------------------===//
30 #ifndef LLVM_SUPPORT_CONSTANT_RANGE_H
31 #define LLVM_SUPPORT_CONSTANT_RANGE_H
33 #include "llvm/ADT/APInt.h"
34 #include "llvm/Support/DataTypes.h"
35 #include "llvm/Support/Streams.h"
42 static ConstantRange intersect1Wrapped(const ConstantRange &LHS,
43 const ConstantRange &RHS);
45 /// Initialize a full (the default) or empty set for the specified bit width.
47 ConstantRange(uint32_t BitWidth, bool isFullSet = true);
49 /// Initialize a range to hold the single specified value.
51 ConstantRange(const APInt &Value);
53 /// @brief Initialize a range of values explicitly. This will assert out if
54 /// Lower==Upper and Lower != Min or Max value for its type. It will also
55 /// assert out if the two APInt's are not the same bit width.
56 ConstantRange(const APInt& Lower, const APInt& Upper);
58 /// getLower - Return the lower value for this range...
60 const APInt &getLower() const { return Lower; }
62 /// getUpper - Return the upper value for this range...
64 const APInt &getUpper() const { return Upper; }
66 /// getBitWidth - get the bit width of this ConstantRange
68 uint32_t getBitWidth() const { return Lower.getBitWidth(); }
70 /// isFullSet - Return true if this set contains all of the elements possible
71 /// for this data-type
73 bool isFullSet() const;
75 /// isEmptySet - Return true if this set contains no members.
77 bool isEmptySet() const;
79 /// isWrappedSet - Return true if this set wraps around the top of the range,
80 /// for example: [100, 8)
82 bool isWrappedSet() const;
84 /// contains - Return true if the specified value is in the set.
86 bool contains(const APInt &Val) const;
88 /// getSingleElement - If this set contains a single element, return it,
89 /// otherwise return null.
91 const APInt *getSingleElement() const {
92 if (Upper == Lower + 1)
97 /// isSingleElement - Return true if this set contains exactly one member.
99 bool isSingleElement() const { return getSingleElement() != 0; }
101 /// getSetSize - Return the number of elements in this set.
103 APInt getSetSize() const;
105 /// getUnsignedMax - Return the largest unsigned value contained in the
108 APInt getUnsignedMax() const;
110 /// getUnsignedMin - Return the smallest unsigned value contained in the
113 APInt getUnsignedMin() const;
115 /// getSignedMax - Return the largest signed value contained in the
118 APInt getSignedMax() const;
120 /// getSignedMin - Return the smallest signed value contained in the
123 APInt getSignedMin() const;
125 /// operator== - Return true if this range is equal to another range.
127 bool operator==(const ConstantRange &CR) const {
128 return Lower == CR.Lower && Upper == CR.Upper;
130 bool operator!=(const ConstantRange &CR) const {
131 return !operator==(CR);
134 /// subtract - Subtract the specified constant from the endpoints of this
136 ConstantRange subtract(const APInt &CI) const;
138 /// intersectWith - Return the range that results from the intersection of
139 /// this range with another range. The resultant range is pruned as much as
140 /// possible, but there may be cases where elements are included that are in
141 /// one of the sets but not the other. For example: [100, 8) intersect [3,
142 /// 120) yields [3, 120)
144 ConstantRange intersectWith(const ConstantRange &CR) const;
146 /// maximalIntersectWith - Return the range that results from the intersection
147 /// of this range with another range. The resultant range is guaranteed to
148 /// include all elements contained in both input ranges, and to have the
149 /// smallest possible set size that does so. Because there may be two
150 /// intersections with the same set size, A.maximalIntersectWith(B) might not
151 /// be equal to B.maximalIntersectWith(A).
153 ConstantRange maximalIntersectWith(const ConstantRange &CR) const;
155 /// unionWith - Return the range that results from the union of this range
156 /// with another range. The resultant range is guaranteed to include the
157 /// elements of both sets, but may contain more. For example, [3, 9) union
158 /// [12,15) is [3, 15), which includes 9, 10, and 11, which were not included
159 /// in either set before.
161 ConstantRange unionWith(const ConstantRange &CR) const;
163 /// zeroExtend - Return a new range in the specified integer type, which must
164 /// be strictly larger than the current type. The returned range will
165 /// correspond to the possible range of values if the source range had been
166 /// zero extended to BitWidth.
167 ConstantRange zeroExtend(uint32_t BitWidth) const;
169 /// signExtend - Return a new range in the specified integer type, which must
170 /// be strictly larger than the current type. The returned range will
171 /// correspond to the possible range of values if the source range had been
172 /// sign extended to BitWidth.
173 ConstantRange signExtend(uint32_t BitWidth) const;
175 /// truncate - Return a new range in the specified integer type, which must be
176 /// strictly smaller than the current type. The returned range will
177 /// correspond to the possible range of values if the source range had been
178 /// truncated to the specified type.
179 ConstantRange truncate(uint32_t BitWidth) const;
181 /// print - Print out the bounds to a stream...
183 void print(std::ostream &OS) const;
184 void print(std::ostream *OS) const { if (OS) print(*OS); }
186 /// dump - Allow printing from a debugger easily...
191 inline std::ostream &operator<<(std::ostream &OS, const ConstantRange &CR) {
196 } // End llvm namespace