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/System/DataTypes.h"
42 /// ConstantRange - This class represents an range of values.
46 static ConstantRange intersect1Wrapped(const ConstantRange &LHS,
47 const ConstantRange &RHS);
50 /// Initialize a full (the default) or empty set for the specified bit width.
52 explicit ConstantRange(uint32_t BitWidth, bool isFullSet = true);
54 /// Initialize a range to hold the single specified value.
56 ConstantRange(const APInt &Value);
57 ConstantRange(const ConstantInt *Value);
59 /// @brief Initialize a range of values explicitly. This will assert out if
60 /// Lower==Upper and Lower != Min or Max value for its type. It will also
61 /// assert out if the two APInt's are not the same bit width.
62 ConstantRange(const APInt& Lower, const APInt& Upper);
64 /// makeICmpRegion - Produce the smallest range that contains all values that
65 /// might satisfy the comparison specified by Pred when compared to any value
66 /// contained within Other.
68 /// Solves for range X in 'for all x in X, there exists a y in Y such that
69 /// icmp op x, y is true'. Every value that might make the comparison true
70 /// is included in the resulting range.
71 static ConstantRange makeICmpRegion(unsigned Pred,
72 const ConstantRange &Other);
74 /// getLower - Return the lower value for this range...
76 const APInt &getLower() const { return Lower; }
78 /// getUpper - Return the upper value for this range...
80 const APInt &getUpper() const { return Upper; }
82 /// getBitWidth - get the bit width of this ConstantRange
84 uint32_t getBitWidth() const { return Lower.getBitWidth(); }
86 /// isFullSet - Return true if this set contains all of the elements possible
87 /// for this data-type
89 bool isFullSet() const;
91 /// isEmptySet - Return true if this set contains no members.
93 bool isEmptySet() const;
95 /// isWrappedSet - Return true if this set wraps around the top of the range,
96 /// for example: [100, 8)
98 bool isWrappedSet() 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 /// intersectWith - Return the range that results from the intersection of
159 /// this range with another range. The resultant range is guaranteed to
160 /// include all elements contained in both input ranges, and to have the
161 /// smallest possible set size that does so. Because there may be two
162 /// intersections with the same set size, A.intersectWith(B) might not
163 /// be equal to B.intersectWith(A).
165 ConstantRange intersectWith(const ConstantRange &CR) const;
167 /// unionWith - Return the range that results from the union of this range
168 /// with another range. The resultant range is guaranteed to include the
169 /// elements of both sets, but may contain more. For example, [3, 9) union
170 /// [12,15) is [3, 15), which includes 9, 10, and 11, which were not included
171 /// in either set before.
173 ConstantRange unionWith(const ConstantRange &CR) const;
175 /// zeroExtend - Return a new range in the specified integer type, which must
176 /// be strictly larger than the current type. The returned range will
177 /// correspond to the possible range of values if the source range had been
178 /// zero extended to BitWidth.
179 ConstantRange zeroExtend(uint32_t BitWidth) const;
181 /// signExtend - Return a new range in the specified integer type, which must
182 /// be strictly larger than the current type. The returned range will
183 /// correspond to the possible range of values if the source range had been
184 /// sign extended to BitWidth.
185 ConstantRange signExtend(uint32_t BitWidth) const;
187 /// truncate - Return a new range in the specified integer type, which must be
188 /// strictly smaller than the current type. The returned range will
189 /// correspond to the possible range of values if the source range had been
190 /// truncated to the specified type.
191 ConstantRange truncate(uint32_t BitWidth) const;
193 /// zextOrTrunc - make this range have the bit width given by \p BitWidth. The
194 /// value is zero extended, truncated, or left alone to make it that width.
195 ConstantRange zextOrTrunc(uint32_t BitWidth) const;
197 /// sextOrTrunc - make this range have the bit width given by \p BitWidth. The
198 /// value is sign extended, truncated, or left alone to make it that width.
199 ConstantRange sextOrTrunc(uint32_t BitWidth) const;
201 /// add - Return a new range representing the possible values resulting
202 /// from an addition of a value in this range and a value in Other.
203 ConstantRange add(const ConstantRange &Other) const;
205 /// multiply - Return a new range representing the possible values resulting
206 /// from a multiplication of a value in this range and a value in Other.
207 /// TODO: This isn't fully implemented yet.
208 ConstantRange multiply(const ConstantRange &Other) const;
210 /// smax - Return a new range representing the possible values resulting
211 /// from a signed maximum of a value in this range and a value in Other.
212 ConstantRange smax(const ConstantRange &Other) const;
214 /// umax - Return a new range representing the possible values resulting
215 /// from an unsigned maximum of a value in this range and a value in Other.
216 ConstantRange umax(const ConstantRange &Other) const;
218 /// udiv - Return a new range representing the possible values resulting
219 /// from an unsigned division of a value in this range and a value in Other.
220 /// TODO: This isn't fully implemented yet.
221 ConstantRange udiv(const ConstantRange &Other) const;
223 /// shl - Return a new range representing the possible values resulting
224 /// from a left shift of a value in this range by the Amount value.
225 ConstantRange shl(const ConstantRange &Amount) const;
227 /// ashr - Return a new range representing the possible values resulting from
228 /// an arithmetic right shift of a value in this range by the Amount value.
229 ConstantRange ashr(const ConstantRange &Amount) const;
231 /// shr - Return a new range representing the possible values resulting
232 /// from a logical right shift of a value in this range by the Amount value.
233 ConstantRange lshr(const ConstantRange &Amount) const;
235 /// print - Print out the bounds to a stream...
237 void print(raw_ostream &OS) const;
239 /// dump - Allow printing from a debugger easily...
244 inline raw_ostream &operator<<(raw_ostream &OS, const ConstantRange &CR) {
249 } // End llvm namespace