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"
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 - Produce the smallest range that contains all values that
62 /// might satisfy the comparison specified by Pred when compared to any value
63 /// contained within Other.
65 /// Solves for range X in 'for all x in X, there exists a y in Y such that
66 /// icmp op x, y is true'. Every value that might make the comparison true
67 /// is included in the resulting range.
68 static ConstantRange makeICmpRegion(unsigned Pred,
69 const ConstantRange &Other);
71 /// getLower - Return the lower value for this range...
73 const APInt &getLower() const { return Lower; }
75 /// getUpper - Return the upper value for this range...
77 const APInt &getUpper() const { return Upper; }
79 /// getBitWidth - get the bit width of this ConstantRange
81 uint32_t getBitWidth() const { return Lower.getBitWidth(); }
83 /// isFullSet - Return true if this set contains all of the elements possible
84 /// for this data-type
86 bool isFullSet() const;
88 /// isEmptySet - Return true if this set contains no members.
90 bool isEmptySet() const;
92 /// isWrappedSet - Return true if this set wraps around the top of the range,
93 /// for example: [100, 8)
95 bool isWrappedSet() const;
97 /// contains - Return true if the specified value is in the set.
99 bool contains(const APInt &Val) const;
101 /// contains - Return true if the other range is a subset of this one.
103 bool contains(const ConstantRange &CR) const;
105 /// getSingleElement - If this set contains a single element, return it,
106 /// otherwise return null.
108 const APInt *getSingleElement() const {
109 if (Upper == Lower + 1)
114 /// isSingleElement - Return true if this set contains exactly one member.
116 bool isSingleElement() const { return getSingleElement() != 0; }
118 /// getSetSize - Return the number of elements in this set.
120 APInt getSetSize() const;
122 /// getUnsignedMax - Return the largest unsigned value contained in the
125 APInt getUnsignedMax() const;
127 /// getUnsignedMin - Return the smallest unsigned value contained in the
130 APInt getUnsignedMin() const;
132 /// getSignedMax - Return the largest signed value contained in the
135 APInt getSignedMax() const;
137 /// getSignedMin - Return the smallest signed value contained in the
140 APInt getSignedMin() const;
142 /// operator== - Return true if this range is equal to another range.
144 bool operator==(const ConstantRange &CR) const {
145 return Lower == CR.Lower && Upper == CR.Upper;
147 bool operator!=(const ConstantRange &CR) const {
148 return !operator==(CR);
151 /// subtract - Subtract the specified constant from the endpoints of this
153 ConstantRange subtract(const APInt &CI) const;
155 /// intersectWith - Return the range that results from the intersection of
156 /// this range with another range. The resultant range is guaranteed to
157 /// include all elements contained in both input ranges, and to have the
158 /// smallest possible set size that does so. Because there may be two
159 /// intersections with the same set size, A.intersectWith(B) might not
160 /// be equal to B.intersectWith(A).
162 ConstantRange intersectWith(const ConstantRange &CR) const;
164 /// unionWith - Return the range that results from the union of this range
165 /// with another range. The resultant range is guaranteed to include the
166 /// elements of both sets, but may contain more. For example, [3, 9) union
167 /// [12,15) is [3, 15), which includes 9, 10, and 11, which were not included
168 /// in either set before.
170 ConstantRange unionWith(const ConstantRange &CR) const;
172 /// zeroExtend - Return a new range in the specified integer type, which must
173 /// be strictly larger than the current type. The returned range will
174 /// correspond to the possible range of values if the source range had been
175 /// zero extended to BitWidth.
176 ConstantRange zeroExtend(uint32_t BitWidth) const;
178 /// signExtend - Return a new range in the specified integer type, which must
179 /// be strictly larger than the current type. The returned range will
180 /// correspond to the possible range of values if the source range had been
181 /// sign extended to BitWidth.
182 ConstantRange signExtend(uint32_t BitWidth) const;
184 /// truncate - Return a new range in the specified integer type, which must be
185 /// strictly smaller than the current type. The returned range will
186 /// correspond to the possible range of values if the source range had been
187 /// truncated to the specified type.
188 ConstantRange truncate(uint32_t BitWidth) const;
190 /// zextOrTrunc - make this range have the bit width given by \p BitWidth. The
191 /// value is zero extended, truncated, or left alone to make it that width.
192 ConstantRange zextOrTrunc(uint32_t BitWidth) const;
194 /// sextOrTrunc - make this range have the bit width given by \p BitWidth. The
195 /// value is sign extended, truncated, or left alone to make it that width.
196 ConstantRange sextOrTrunc(uint32_t BitWidth) const;
198 /// add - Return a new range representing the possible values resulting
199 /// from an addition of a value in this range and a value in Other.
200 ConstantRange add(const ConstantRange &Other) const;
202 /// multiply - Return a new range representing the possible values resulting
203 /// from a multiplication of a value in this range and a value in Other.
204 /// TODO: This isn't fully implemented yet.
205 ConstantRange multiply(const ConstantRange &Other) const;
207 /// smax - Return a new range representing the possible values resulting
208 /// from a signed maximum of a value in this range and a value in Other.
209 ConstantRange smax(const ConstantRange &Other) const;
211 /// umax - Return a new range representing the possible values resulting
212 /// from an unsigned maximum of a value in this range and a value in Other.
213 ConstantRange umax(const ConstantRange &Other) const;
215 /// udiv - Return a new range representing the possible values resulting
216 /// from an unsigned division of a value in this range and a value in Other.
217 /// TODO: This isn't fully implemented yet.
218 ConstantRange udiv(const ConstantRange &Other) const;
220 /// shl - Return a new range representing the possible values resulting
221 /// from a left shift of a value in this range by the Amount value.
222 ConstantRange shl(const ConstantRange &Amount) const;
224 /// ashr - Return a new range representing the possible values resulting from
225 /// an arithmetic right shift of a value in this range by the Amount value.
226 ConstantRange ashr(const ConstantRange &Amount) const;
228 /// shr - Return a new range representing the possible values resulting
229 /// from a logical right shift of a value in this range by the Amount value.
230 ConstantRange lshr(const ConstantRange &Amount) const;
232 /// print - Print out the bounds to a stream...
234 void print(raw_ostream &OS) const;
236 /// dump - Allow printing from a debugger easily...
241 inline raw_ostream &operator<<(raw_ostream &OS, const ConstantRange &CR) {
246 } // End llvm namespace