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.
46 /// Initialize a full (the default) or empty set for the specified bit width.
48 explicit ConstantRange(uint32_t BitWidth, bool isFullSet = true);
50 /// Initialize a range to hold the single specified value.
52 ConstantRange(const APInt &Value);
54 /// @brief Initialize a range of values explicitly. This will assert out if
55 /// Lower==Upper and Lower != Min or Max value for its type. It will also
56 /// assert out if the two APInt's are not the same bit width.
57 ConstantRange(const APInt &Lower, const APInt &Upper);
59 /// makeICmpRegion - Produce the smallest range that contains all values that
60 /// might satisfy the comparison specified by Pred when compared to any value
61 /// contained within Other.
63 /// Solves for range X in 'for all x in X, there exists a y in Y such that
64 /// icmp op x, y is true'. Every value that might make the comparison true
65 /// is included in the resulting range.
66 static ConstantRange makeICmpRegion(unsigned Pred,
67 const ConstantRange &Other);
69 /// getLower - Return the lower value for this range...
71 const APInt &getLower() const { return Lower; }
73 /// getUpper - Return the upper value for this range...
75 const APInt &getUpper() const { return Upper; }
77 /// getBitWidth - get the bit width of this ConstantRange
79 uint32_t getBitWidth() const { return Lower.getBitWidth(); }
81 /// isFullSet - Return true if this set contains all of the elements possible
82 /// for this data-type
84 bool isFullSet() const;
86 /// isEmptySet - Return true if this set contains no members.
88 bool isEmptySet() const;
90 /// isWrappedSet - Return true if this set wraps around the top of the range,
91 /// for example: [100, 8)
93 bool isWrappedSet() const;
95 /// isSignWrappedSet - Return true if this set wraps around the INT_MIN of
96 /// its bitwidth, for example: i8 [120, 140).
98 bool isSignWrappedSet() const;
100 /// contains - Return true if the specified value is in the set.
102 bool contains(const APInt &Val) const;
104 /// contains - Return true if the other range is a subset of this one.
106 bool contains(const ConstantRange &CR) const;
108 /// getSingleElement - If this set contains a single element, return it,
109 /// otherwise return null.
111 const APInt *getSingleElement() const {
112 if (Upper == Lower + 1)
117 /// isSingleElement - Return true if this set contains exactly one member.
119 bool isSingleElement() const { return getSingleElement() != 0; }
121 /// getSetSize - Return the number of elements in this set.
123 APInt getSetSize() const;
125 /// getUnsignedMax - Return the largest unsigned value contained in the
128 APInt getUnsignedMax() const;
130 /// getUnsignedMin - Return the smallest unsigned value contained in the
133 APInt getUnsignedMin() const;
135 /// getSignedMax - Return the largest signed value contained in the
138 APInt getSignedMax() const;
140 /// getSignedMin - Return the smallest signed value contained in the
143 APInt getSignedMin() const;
145 /// operator== - Return true if this range is equal to another range.
147 bool operator==(const ConstantRange &CR) const {
148 return Lower == CR.Lower && Upper == CR.Upper;
150 bool operator!=(const ConstantRange &CR) const {
151 return !operator==(CR);
154 /// subtract - Subtract the specified constant from the endpoints of this
156 ConstantRange subtract(const APInt &CI) const;
158 /// \brief Subtract the specified range from this range (aka relative
159 /// complement of the sets).
160 ConstantRange difference(const ConstantRange &CR) const;
162 /// intersectWith - Return the range that results from the intersection of
163 /// this range with another range. The resultant range is guaranteed to
164 /// include all elements contained in both input ranges, and to have the
165 /// smallest possible set size that does so. Because there may be two
166 /// intersections with the same set size, A.intersectWith(B) might not
167 /// be equal to B.intersectWith(A).
169 ConstantRange intersectWith(const ConstantRange &CR) const;
171 /// unionWith - Return the range that results from the union of this range
172 /// with another range. The resultant range is guaranteed to include the
173 /// elements of both sets, but may contain more. For example, [3, 9) union
174 /// [12,15) is [3, 15), which includes 9, 10, and 11, which were not included
175 /// in either set before.
177 ConstantRange unionWith(const ConstantRange &CR) const;
179 /// zeroExtend - Return a new range in the specified integer type, which must
180 /// be strictly larger than the current type. The returned range will
181 /// correspond to the possible range of values if the source range had been
182 /// zero extended to BitWidth.
183 ConstantRange zeroExtend(uint32_t BitWidth) const;
185 /// signExtend - Return a new range in the specified integer type, which must
186 /// be strictly larger than the current type. The returned range will
187 /// correspond to the possible range of values if the source range had been
188 /// sign extended to BitWidth.
189 ConstantRange signExtend(uint32_t BitWidth) const;
191 /// truncate - Return a new range in the specified integer type, which must be
192 /// strictly smaller than the current type. The returned range will
193 /// correspond to the possible range of values if the source range had been
194 /// truncated to the specified type.
195 ConstantRange truncate(uint32_t BitWidth) const;
197 /// zextOrTrunc - make this range have the bit width given by \p BitWidth. The
198 /// value is zero extended, truncated, or left alone to make it that width.
199 ConstantRange zextOrTrunc(uint32_t BitWidth) const;
201 /// sextOrTrunc - make this range have the bit width given by \p BitWidth. The
202 /// value is sign extended, truncated, or left alone to make it that width.
203 ConstantRange sextOrTrunc(uint32_t BitWidth) const;
205 /// add - Return a new range representing the possible values resulting
206 /// from an addition of a value in this range and a value in \p Other.
207 ConstantRange add(const ConstantRange &Other) const;
209 /// sub - Return a new range representing the possible values resulting
210 /// from a subtraction of a value in this range and a value in \p Other.
211 ConstantRange sub(const ConstantRange &Other) const;
213 /// multiply - Return a new range representing the possible values resulting
214 /// from a multiplication of a value in this range and a value in \p Other.
215 /// TODO: This isn't fully implemented yet.
216 ConstantRange multiply(const ConstantRange &Other) const;
218 /// smax - Return a new range representing the possible values resulting
219 /// from a signed maximum of a value in this range and a value in \p Other.
220 ConstantRange smax(const ConstantRange &Other) const;
222 /// umax - Return a new range representing the possible values resulting
223 /// from an unsigned maximum of a value in this range and a value in \p Other.
224 ConstantRange umax(const ConstantRange &Other) const;
226 /// udiv - Return a new range representing the possible values resulting
227 /// from an unsigned division of a value in this range and a value in
229 ConstantRange udiv(const ConstantRange &Other) const;
231 /// binaryAnd - return a new range representing the possible values resulting
232 /// from a binary-and of a value in this range by a value in \p Other.
233 ConstantRange binaryAnd(const ConstantRange &Other) const;
235 /// binaryOr - return a new range representing the possible values resulting
236 /// from a binary-or of a value in this range by a value in \p Other.
237 ConstantRange binaryOr(const ConstantRange &Other) const;
239 /// shl - Return a new range representing the possible values resulting
240 /// from a left shift of a value in this range by a value in \p Other.
241 /// TODO: This isn't fully implemented yet.
242 ConstantRange shl(const ConstantRange &Other) const;
244 /// lshr - Return a new range representing the possible values resulting
245 /// from a logical right shift of a value in this range and a value in
247 ConstantRange lshr(const ConstantRange &Other) const;
249 /// inverse - Return a new range that is the logical not of the current set.
251 ConstantRange inverse() const;
253 /// print - Print out the bounds to a stream...
255 void print(raw_ostream &OS) const;
257 /// dump - Allow printing from a debugger easily...
262 inline raw_ostream &operator<<(raw_ostream &OS, const ConstantRange &CR) {
267 } // End llvm namespace