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 can be used to represent either signed or
30 //===----------------------------------------------------------------------===//
32 #ifndef LLVM_SUPPORT_CONSTANT_RANGE_H
33 #define LLVM_SUPPORT_CONSTANT_RANGE_H
35 #include "llvm/ADT/APInt.h"
36 #include "llvm/Support/DataTypes.h"
40 /// ConstantRange - This class represents an range of values.
44 static ConstantRange intersect1Wrapped(const ConstantRange &LHS,
45 const ConstantRange &RHS);
48 /// Initialize a full (the default) or empty set for the specified bit width.
50 explicit ConstantRange(uint32_t BitWidth, bool isFullSet = true);
52 /// Initialize a range to hold the single specified value.
54 ConstantRange(const APInt &Value);
56 /// @brief Initialize a range of values explicitly. This will assert out if
57 /// Lower==Upper and Lower != Min or Max value for its type. It will also
58 /// assert out if the two APInt's are not the same bit width.
59 ConstantRange(const APInt& Lower, const APInt& Upper);
61 /// makeICmpRegion - Return the range of values that a value must be within
62 /// in order for the comparison specified by the predicate against range
64 static ConstantRange makeICmpRegion(unsigned Pred,
65 const ConstantRange &Other);
67 /// getLower - Return the lower value for this range...
69 const APInt &getLower() const { return Lower; }
71 /// getUpper - Return the upper value for this range...
73 const APInt &getUpper() const { return Upper; }
75 /// getBitWidth - get the bit width of this ConstantRange
77 uint32_t getBitWidth() const { return Lower.getBitWidth(); }
79 /// isFullSet - Return true if this set contains all of the elements possible
80 /// for this data-type
82 bool isFullSet() const;
84 /// isEmptySet - Return true if this set contains no members.
86 bool isEmptySet() const;
88 /// isWrappedSet - Return true if this set wraps around the top of the range,
89 /// for example: [100, 8)
91 bool isWrappedSet() const;
93 /// contains - Return true if the specified value is in the set.
95 bool contains(const APInt &Val) const;
97 /// contains - Return true if the other range is a subset of this one.
99 bool contains(const ConstantRange &CR) const;
101 /// getSingleElement - If this set contains a single element, return it,
102 /// otherwise return null.
104 const APInt *getSingleElement() const {
105 if (Upper == Lower + 1)
110 /// isSingleElement - Return true if this set contains exactly one member.
112 bool isSingleElement() const { return getSingleElement() != 0; }
114 /// getSetSize - Return the number of elements in this set.
116 APInt getSetSize() const;
118 /// getUnsignedMax - Return the largest unsigned value contained in the
121 APInt getUnsignedMax() const;
123 /// getUnsignedMin - Return the smallest unsigned value contained in the
126 APInt getUnsignedMin() const;
128 /// getSignedMax - Return the largest signed value contained in the
131 APInt getSignedMax() const;
133 /// getSignedMin - Return the smallest signed value contained in the
136 APInt getSignedMin() const;
138 /// operator== - Return true if this range is equal to another range.
140 bool operator==(const ConstantRange &CR) const {
141 return Lower == CR.Lower && Upper == CR.Upper;
143 bool operator!=(const ConstantRange &CR) const {
144 return !operator==(CR);
147 /// subtract - Subtract the specified constant from the endpoints of this
149 ConstantRange subtract(const APInt &CI) const;
151 /// intersectWith - Return the range that results from the intersection of
152 /// this range with another range. The resultant range is pruned as much as
153 /// possible, but there may be cases where elements are included that are in
154 /// one of the sets but not the other. For example: [100, 8) intersect [3,
155 /// 120) yields [3, 120)
157 ConstantRange intersectWith(const ConstantRange &CR) const;
159 /// maximalIntersectWith - Return the range that results from the intersection
160 /// of this range with another range. The resultant range is guaranteed to
161 /// include all elements contained in both input ranges, and to have the
162 /// smallest possible set size that does so. Because there may be two
163 /// intersections with the same set size, A.maximalIntersectWith(B) might not
164 /// be equal to B.maximalIntersectWith(A).
166 ConstantRange maximalIntersectWith(const ConstantRange &CR) const;
168 /// unionWith - Return the range that results from the union of this range
169 /// with another range. The resultant range is guaranteed to include the
170 /// elements of both sets, but may contain more. For example, [3, 9) union
171 /// [12,15) is [3, 15), which includes 9, 10, and 11, which were not included
172 /// in either set before.
174 ConstantRange unionWith(const ConstantRange &CR) const;
176 /// zeroExtend - Return a new range in the specified integer type, which must
177 /// be strictly larger than the current type. The returned range will
178 /// correspond to the possible range of values if the source range had been
179 /// zero extended to BitWidth.
180 ConstantRange zeroExtend(uint32_t BitWidth) const;
182 /// signExtend - 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 /// sign extended to BitWidth.
186 ConstantRange signExtend(uint32_t BitWidth) const;
188 /// truncate - Return a new range in the specified integer type, which must be
189 /// strictly smaller than the current type. The returned range will
190 /// correspond to the possible range of values if the source range had been
191 /// truncated to the specified type.
192 ConstantRange truncate(uint32_t BitWidth) const;
194 /// add - Return a new range representing the possible values resulting
195 /// from an addition of a value in this range and a value in Other.
196 ConstantRange add(const ConstantRange &Other) const;
198 /// multiply - Return a new range representing the possible values resulting
199 /// from a multiplication of a value in this range and a value in Other.
200 /// TODO: This isn't fully implemented yet.
201 ConstantRange multiply(const ConstantRange &Other) const;
203 /// smax - Return a new range representing the possible values resulting
204 /// from a signed maximum of a value in this range and a value in Other.
205 ConstantRange smax(const ConstantRange &Other) const;
207 /// umax - Return a new range representing the possible values resulting
208 /// from an unsigned maximum of a value in this range and a value in Other.
209 ConstantRange umax(const ConstantRange &Other) const;
211 /// udiv - Return a new range representing the possible values resulting
212 /// from an unsigned division of a value in this range and a value in Other.
213 /// TODO: This isn't fully implemented yet.
214 ConstantRange udiv(const ConstantRange &Other) const;
216 /// print - Print out the bounds to a stream...
218 void print(raw_ostream &OS) const;
220 /// dump - Allow printing from a debugger easily...
225 inline raw_ostream &operator<<(raw_ostream &OS, const ConstantRange &CR) {
230 std::ostream &operator<<(std::ostream &OS, const ConstantRange &CR);
232 } // End llvm namespace