1 //===-- llvm/Support/ConstantRange.h - Represent a range --------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 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: : 16 // 17 // [F, F) = {} = Empty set 18 // [T, F) = {T} 19 // [F, T) = {F} 20 // [T, T) = {F, T} = Full set 21 // 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 26 // 27 // Note that ConstantRange can be used to represent either signed or 28 // unsigned ranges. 29 // 30 //===----------------------------------------------------------------------===// 31 32 #ifndef LLVM_SUPPORT_CONSTANT_RANGE_H 33 #define LLVM_SUPPORT_CONSTANT_RANGE_H 34 35 #include "llvm/ADT/APInt.h" 36 #include "llvm/Support/DataTypes.h" 37 38 namespace llvm { 39 40 /// ConstantRange - This class represents an range of values. 41 /// 42 class ConstantRange { 43 APInt Lower, Upper; 44 45 public: 46 /// Initialize a full (the default) or empty set for the specified bit width. 47 /// 48 explicit ConstantRange(uint32_t BitWidth, bool isFullSet = true); 49 50 /// Initialize a range to hold the single specified value. 51 /// 52 ConstantRange(const APInt &Value); 53 54 /// @brief Initialize a range of values explicitly. This will assert out if 55 /// Lower==Upper and Lower != Min or Max value for its type. It will also 56 /// assert out if the two APInt's are not the same bit width. 57 ConstantRange(const APInt &Lower, const APInt &Upper); 58 59 /// makeICmpRegion - Produce the smallest range that contains all values that 60 /// might satisfy the comparison specified by Pred when compared to any value 61 /// contained within Other. 62 /// 63 /// Solves for range X in 'for all x in X, there exists a y in Y such that 64 /// icmp op x, y is true'. Every value that might make the comparison true 65 /// is included in the resulting range. 66 static ConstantRange makeICmpRegion(unsigned Pred, 67 const ConstantRange &Other); 68 69 /// getLower - Return the lower value for this range... 70 /// getLower()71 const APInt &getLower() const { return Lower; } 72 73 /// getUpper - Return the upper value for this range... 74 /// getUpper()75 const APInt &getUpper() const { return Upper; } 76 77 /// getBitWidth - get the bit width of this ConstantRange 78 /// getBitWidth()79 uint32_t getBitWidth() const { return Lower.getBitWidth(); } 80 81 /// isFullSet - Return true if this set contains all of the elements possible 82 /// for this data-type 83 /// 84 bool isFullSet() const; 85 86 /// isEmptySet - Return true if this set contains no members. 87 /// 88 bool isEmptySet() const; 89 90 /// isWrappedSet - Return true if this set wraps around the top of the range, 91 /// for example: [100, 8) 92 /// 93 bool isWrappedSet() const; 94 95 /// isSignWrappedSet - Return true if this set wraps around the INT_MIN of 96 /// its bitwidth, for example: i8 [120, 140). 97 /// 98 bool isSignWrappedSet() const; 99 100 /// contains - Return true if the specified value is in the set. 101 /// 102 bool contains(const APInt &Val) const; 103 104 /// contains - Return true if the other range is a subset of this one. 105 /// 106 bool contains(const ConstantRange &CR) const; 107 108 /// getSingleElement - If this set contains a single element, return it, 109 /// otherwise return null. 110 /// getSingleElement()111 const APInt *getSingleElement() const { 112 if (Upper == Lower + 1) 113 return &Lower; 114 return 0; 115 } 116 117 /// isSingleElement - Return true if this set contains exactly one member. 118 /// isSingleElement()119 bool isSingleElement() const { return getSingleElement() != 0; } 120 121 /// getSetSize - Return the number of elements in this set. 122 /// 123 APInt getSetSize() const; 124 125 /// getUnsignedMax - Return the largest unsigned value contained in the 126 /// ConstantRange. 127 /// 128 APInt getUnsignedMax() const; 129 130 /// getUnsignedMin - Return the smallest unsigned value contained in the 131 /// ConstantRange. 132 /// 133 APInt getUnsignedMin() const; 134 135 /// getSignedMax - Return the largest signed value contained in the 136 /// ConstantRange. 137 /// 138 APInt getSignedMax() const; 139 140 /// getSignedMin - Return the smallest signed value contained in the 141 /// ConstantRange. 142 /// 143 APInt getSignedMin() const; 144 145 /// operator== - Return true if this range is equal to another range. 146 /// 147 bool operator==(const ConstantRange &CR) const { 148 return Lower == CR.Lower && Upper == CR.Upper; 149 } 150 bool operator!=(const ConstantRange &CR) const { 151 return !operator==(CR); 152 } 153 154 /// subtract - Subtract the specified constant from the endpoints of this 155 /// constant range. 156 ConstantRange subtract(const APInt &CI) const; 157 158 /// 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). 164 /// 165 ConstantRange intersectWith(const ConstantRange &CR) const; 166 167 /// 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. 172 /// 173 ConstantRange unionWith(const ConstantRange &CR) const; 174 175 /// 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; 180 181 /// 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; 186 187 /// 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; 192 193 /// 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; 196 197 /// 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; 200 201 /// add - Return a new range representing the possible values resulting 202 /// from an addition of a value in this range and a value in \p Other. 203 ConstantRange add(const ConstantRange &Other) const; 204 205 /// sub - Return a new range representing the possible values resulting 206 /// from a subtraction of a value in this range and a value in \p Other. 207 ConstantRange sub(const ConstantRange &Other) const; 208 209 /// multiply - Return a new range representing the possible values resulting 210 /// from a multiplication of a value in this range and a value in \p Other. 211 /// TODO: This isn't fully implemented yet. 212 ConstantRange multiply(const ConstantRange &Other) const; 213 214 /// smax - Return a new range representing the possible values resulting 215 /// from a signed maximum of a value in this range and a value in \p Other. 216 ConstantRange smax(const ConstantRange &Other) const; 217 218 /// umax - Return a new range representing the possible values resulting 219 /// from an unsigned maximum of a value in this range and a value in \p Other. 220 ConstantRange umax(const ConstantRange &Other) const; 221 222 /// udiv - Return a new range representing the possible values resulting 223 /// from an unsigned division of a value in this range and a value in 224 /// \p Other. 225 ConstantRange udiv(const ConstantRange &Other) const; 226 227 /// binaryAnd - return a new range representing the possible values resulting 228 /// from a binary-and of a value in this range by a value in \p Other. 229 ConstantRange binaryAnd(const ConstantRange &Other) const; 230 231 /// binaryOr - return a new range representing the possible values resulting 232 /// from a binary-or of a value in this range by a value in \p Other. 233 ConstantRange binaryOr(const ConstantRange &Other) const; 234 235 /// shl - Return a new range representing the possible values resulting 236 /// from a left shift of a value in this range by a value in \p Other. 237 /// TODO: This isn't fully implemented yet. 238 ConstantRange shl(const ConstantRange &Other) const; 239 240 /// lshr - Return a new range representing the possible values resulting 241 /// from a logical right shift of a value in this range and a value in 242 /// \p Other. 243 ConstantRange lshr(const ConstantRange &Other) const; 244 245 /// inverse - Return a new range that is the logical not of the current set. 246 /// 247 ConstantRange inverse() const; 248 249 /// print - Print out the bounds to a stream... 250 /// 251 void print(raw_ostream &OS) const; 252 253 /// dump - Allow printing from a debugger easily... 254 /// 255 void dump() const; 256 }; 257 258 inline raw_ostream &operator<<(raw_ostream &OS, const ConstantRange &CR) { 259 CR.print(OS); 260 return OS; 261 } 262 263 } // End llvm namespace 264 265 #endif 266