1 //===-- llvm/Support/ConstantRange.h - Represent a range --------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source 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 always keeps unsigned values.
28 //===----------------------------------------------------------------------===//
30 #ifndef LLVM_SUPPORT_CONSTANT_RANGE_H
31 #define LLVM_SUPPORT_CONSTANT_RANGE_H
33 #include "llvm/ADT/APInt.h"
34 #include "llvm/Support/DataTypes.h"
35 #include "llvm/Support/Streams.h"
45 static ConstantRange intersect1Wrapped(const ConstantRange &LHS,
46 const ConstantRange &RHS, bool sign);
48 /// Initialize a full (the default) or empty set for the specified type.
50 ConstantRange(const Type *Ty, bool isFullSet = true);
52 /// Initialize a range to hold the single specified value.
54 ConstantRange(Constant *Value);
56 /// Initialize a range of values explicitly... this will assert out if
57 /// Lower==Upper and Lower != Min or Max for its type, if the two constants
58 /// have different types, or if the constant are not integral values.
60 ConstantRange(Constant *Lower, Constant *Upper);
62 /// @brief Initialize a range of values explicitly.
63 ConstantRange(const APInt& Lower, const APInt& Upper);
65 /// Initialize a set of values that all satisfy the predicate with C. The
66 /// predicate should be either an ICmpInst::Predicate or FCmpInst::Predicate
68 /// @brief Get a range for a relation with a constant integral.
69 ConstantRange(unsigned short predicate, ConstantInt *C);
71 /// getLower - Return the lower value for this range...
73 ConstantInt *getLower() const;
75 /// getUpper - Return the upper value for this range...
77 ConstantInt *getUpper() const;
79 /// getType - Return the LLVM data type of this range.
81 const Type *getType() const;
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(bool isSigned) const;
97 /// contains - Return true if the specified value is in the set.
98 /// The isSigned parameter indicates whether the comparisons should be
99 /// performed as if the values are signed or not.
101 bool contains(ConstantInt *Val, bool isSigned) const;
103 /// getSingleElement - If this set contains a single element, return it,
104 /// otherwise return null.
106 ConstantInt *getSingleElement() const;
108 /// isSingleElement - Return true if this set contains exactly one member.
110 bool isSingleElement() const { return getSingleElement() != 0; }
112 /// getSetSize - Return the number of elements in this set.
114 APInt getSetSize() const;
116 /// operator== - Return true if this range is equal to another range.
118 bool operator==(const ConstantRange &CR) const {
119 return Lower == CR.Lower && Upper == CR.Upper;
121 bool operator!=(const ConstantRange &CR) const {
122 return !operator==(CR);
125 /// subtract - Subtract the specified constant from the endpoints of this
127 ConstantRange subtract(ConstantInt *CI) const;
129 /// intersectWith - Return the range that results from the intersection of
130 /// this range with another range. The resultant range is pruned as much as
131 /// possible, but there may be cases where elements are included that are in
132 /// one of the sets but not the other. For example: [100, 8) intersect [3,
133 /// 120) yields [3, 120)
135 ConstantRange intersectWith(const ConstantRange &CR, bool isSigned) const;
137 /// unionWith - Return the range that results from the union of this range
138 /// with another range. The resultant range is guaranteed to include the
139 /// elements of both sets, but may contain more. For example, [3, 9) union
140 /// [12,15) is [3, 15), which includes 9, 10, and 11, which were not included
141 /// in either set before.
143 ConstantRange unionWith(const ConstantRange &CR, bool isSigned) const;
145 /// zeroExtend - Return a new range in the specified integer type, which must
146 /// be strictly larger than the current type. The returned range will
147 /// correspond to the possible range of values if the source range had been
149 ConstantRange zeroExtend(const Type *Ty) const;
151 /// truncate - Return a new range in the specified integer type, which must be
152 /// strictly smaller than the current type. The returned range will
153 /// correspond to the possible range of values if the source range had been
154 /// truncated to the specified type.
155 ConstantRange truncate(const Type *Ty) const;
157 /// print - Print out the bounds to a stream...
159 void print(std::ostream &OS) const;
160 void print(std::ostream *OS) const { if (OS) print(*OS); }
162 /// dump - Allow printing from a debugger easily...
167 inline std::ostream &operator<<(std::ostream &OS, const ConstantRange &CR) {
172 } // End llvm namespace