1 //===- 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_IR_CONSTANTRANGE_H
33 #define LLVM_IR_CONSTANTRANGE_H
35 #include "llvm/ADT/APInt.h"
36 #include "llvm/Support/DataTypes.h"
40 /// This class represents a range of values.
45 // If we have move semantics, pass APInts by value and move them into place.
46 typedef APInt APIntMoveTy;
49 /// Initialize a full (the default) or empty set for the specified bit width.
51 explicit ConstantRange(uint32_t BitWidth, bool isFullSet = true);
53 /// Initialize a range to hold the single specified value.
55 ConstantRange(APIntMoveTy Value);
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);
62 /// 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.
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);
72 /// Return the lower value for this range.
74 const APInt &getLower() const { return Lower; }
76 /// Return the upper value for this range.
78 const APInt &getUpper() const { return Upper; }
80 /// Get the bit width of this ConstantRange.
82 uint32_t getBitWidth() const { return Lower.getBitWidth(); }
84 /// Return true if this set contains all of the elements possible
85 /// for this data-type.
87 bool isFullSet() const;
89 /// Return true if this set contains no members.
91 bool isEmptySet() const;
93 /// Return true if this set wraps around the top of the range.
94 /// For example: [100, 8).
96 bool isWrappedSet() const;
98 /// Return true if this set wraps around the INT_MIN of
99 /// its bitwidth. For example: i8 [120, 140).
101 bool isSignWrappedSet() const;
103 /// Return true if the specified value is in the set.
105 bool contains(const APInt &Val) const;
107 /// Return true if the other range is a subset of this one.
109 bool contains(const ConstantRange &CR) const;
111 /// If this set contains a single element, return it, otherwise return null.
113 const APInt *getSingleElement() const {
114 if (Upper == Lower + 1)
119 /// Return true if this set contains exactly one member.
121 bool isSingleElement() const { return getSingleElement() != nullptr; }
123 /// Return the number of elements in this set.
125 APInt getSetSize() const;
127 /// Return the largest unsigned value contained in the ConstantRange.
129 APInt getUnsignedMax() const;
131 /// Return the smallest unsigned value contained in the ConstantRange.
133 APInt getUnsignedMin() const;
135 /// Return the largest signed value contained in the ConstantRange.
137 APInt getSignedMax() const;
139 /// Return the smallest signed value contained in the ConstantRange.
141 APInt getSignedMin() const;
143 /// Return true if this range is equal to another range.
145 bool operator==(const ConstantRange &CR) const {
146 return Lower == CR.Lower && Upper == CR.Upper;
148 bool operator!=(const ConstantRange &CR) const {
149 return !operator==(CR);
152 /// Subtract the specified constant from the endpoints of this constant range.
153 ConstantRange subtract(const APInt &CI) const;
155 /// \brief Subtract the specified range from this range (aka relative
156 /// complement of the sets).
157 ConstantRange difference(const ConstantRange &CR) const;
159 /// Return the range that results from the intersection of
160 /// 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.intersectWith(B) might not
164 /// be equal to B.intersectWith(A).
166 ConstantRange intersectWith(const ConstantRange &CR) const;
168 /// 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 /// 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 /// 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 /// 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 /// Make this range have the bit width given by \p BitWidth. The
195 /// value is zero extended, truncated, or left alone to make it that width.
196 ConstantRange zextOrTrunc(uint32_t BitWidth) const;
198 /// Make this range have the bit width given by \p BitWidth. The
199 /// value is sign extended, truncated, or left alone to make it that width.
200 ConstantRange sextOrTrunc(uint32_t BitWidth) const;
202 /// Return a new range representing the possible values resulting
203 /// from an addition of a value in this range and a value in \p Other.
204 ConstantRange add(const ConstantRange &Other) const;
206 /// Return a new range representing the possible values resulting
207 /// from a subtraction of a value in this range and a value in \p Other.
208 ConstantRange sub(const ConstantRange &Other) const;
210 /// Return a new range representing the possible values resulting
211 /// from a multiplication of a value in this range and a value in \p Other.
212 /// TODO: This isn't fully implemented yet.
213 ConstantRange multiply(const ConstantRange &Other) const;
215 /// Return a new range representing the possible values resulting
216 /// from a signed maximum of a value in this range and a value in \p Other.
217 ConstantRange smax(const ConstantRange &Other) const;
219 /// Return a new range representing the possible values resulting
220 /// from an unsigned maximum of a value in this range and a value in \p Other.
221 ConstantRange umax(const ConstantRange &Other) const;
223 /// Return a new range representing the possible values resulting
224 /// from an unsigned division of a value in this range and a value in
226 ConstantRange udiv(const ConstantRange &Other) const;
228 /// Return a new range representing the possible values resulting
229 /// from a binary-and of a value in this range by a value in \p Other.
230 ConstantRange binaryAnd(const ConstantRange &Other) const;
232 /// Return a new range representing the possible values resulting
233 /// from a binary-or of a value in this range by a value in \p Other.
234 ConstantRange binaryOr(const ConstantRange &Other) const;
236 /// Return a new range representing the possible values resulting
237 /// from a left shift of a value in this range by a value in \p Other.
238 /// TODO: This isn't fully implemented yet.
239 ConstantRange shl(const ConstantRange &Other) const;
241 /// Return a new range representing the possible values resulting from a
242 /// logical right shift of a value in this range and a value in \p Other.
243 ConstantRange lshr(const ConstantRange &Other) const;
245 /// Return a new range that is the logical not of the current set.
247 ConstantRange inverse() const;
249 /// Print out the bounds to a stream.
251 void print(raw_ostream &OS) const;
253 /// Allow printing from a debugger easily.
258 inline raw_ostream &operator<<(raw_ostream &OS, const ConstantRange &CR) {
263 } // End llvm namespace