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
15 // ranges (other integral ranges use min/max values for special range values):
17 // [F, F) = {} = Empty set
20 // [T, T) = {F, T} = Full set
22 //===----------------------------------------------------------------------===//
24 #ifndef LLVM_SUPPORT_CONSTANT_RANGE_H
25 #define LLVM_SUPPORT_CONSTANT_RANGE_H
27 #include "Support/DataTypes.h"
32 class ConstantIntegral;
37 ConstantIntegral *Lower, *Upper;
39 /// Initialize a full (the default) or empty set for the specified type.
41 ConstantRange(const Type *Ty, bool isFullSet = true);
43 /// Initialize a range to hold the single specified value.
45 ConstantRange(Constant *Value);
47 /// Initialize a range of values explicitly... this will assert out if
48 /// Lower==Upper and Lower != Min or Max for its type, if the two constants
49 /// have different types, or if the constant are not integral values.
51 ConstantRange(Constant *Lower, Constant *Upper);
53 /// Initialize a set of values that all satisfy the condition with C.
55 ConstantRange(unsigned SetCCOpcode, ConstantIntegral *C);
57 /// getLower - Return the lower value for this range...
59 ConstantIntegral *getLower() const { return Lower; }
61 /// getUpper - Return the upper value for this range...
63 ConstantIntegral *getUpper() const { return Upper; }
65 /// getType - Return the LLVM data type of this range.
67 const Type *getType() const;
69 /// isFullSet - Return true if this set contains all of the elements possible
70 /// for this data-type
72 bool isFullSet() const;
74 /// isEmptySet - Return true if this set contains no members.
76 bool isEmptySet() const;
78 /// isWrappedSet - Return true if this set wraps around the top of the range,
79 /// for example: [100, 8)
81 bool isWrappedSet() const;
83 /// contains - Return true if the specified value is in the set.
85 bool contains(ConstantInt *Val) const;
87 /// getSingleElement - If this set contains a single element, return it,
88 /// otherwise return null.
90 ConstantIntegral *getSingleElement() const;
92 /// isSingleElement - Return true if this set contains exactly one member.
94 bool isSingleElement() const { return getSingleElement() != 0; }
96 /// getSetSize - Return the number of elements in this set.
98 uint64_t getSetSize() const;
100 /// operator== - Return true if this range is equal to another range.
102 bool operator==(const ConstantRange &CR) const {
103 return Lower == CR.Lower && Upper == CR.Upper;
105 bool operator!=(const ConstantRange &CR) const {
106 return !operator==(CR);
109 /// subtract - Subtract the specified constant from the endpoints of this
111 ConstantRange subtract(ConstantInt *CI) const;
113 /// intersect - Return the range that results from the intersection of this
114 /// range with another range. The resultant range is pruned as much as
115 /// possible, but there may be cases where elements are included that are in
116 /// one of the sets but not the other. For example: [100, 8) intersect [3,
117 /// 120) yields [3, 120)
119 ConstantRange intersectWith(const ConstantRange &CR) const;
121 /// union - Return the range that results from the union of this range with
122 /// another range. The resultant range is guaranteed to include the elements
123 /// of both sets, but may contain more. For example, [3, 9) union [12,15) is
124 /// [3, 15), which includes 9, 10, and 11, which were not included in either
127 ConstantRange unionWith(const ConstantRange &CR) const;
129 /// zeroExtend - Return a new range in the specified integer type, which must
130 /// be strictly larger than the current type. The returned range will
131 /// correspond to the possible range of values if the source range had been
133 ConstantRange zeroExtend(const Type *Ty) const;
135 /// truncate - Return a new range in the specified integer type, which must be
136 /// strictly smaller than the current type. The returned range will
137 /// correspond to the possible range of values if the source range had been
138 /// truncated to the specified type.
139 ConstantRange truncate(const Type *Ty) const;
141 /// print - Print out the bounds to a stream...
143 void print(std::ostream &OS) const;
145 /// dump - Allow printing from a debugger easily...
150 inline std::ostream &operator<<(std::ostream &OS, const ConstantRange &CR) {
155 } // End llvm namespace