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_CONSTANTRANGE_H 33 #define LLVM_SUPPORT_CONSTANTRANGE_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 #if LLVM_HAS_RVALUE_REFERENCES 46 // If we have move semantics, pass APInts by value and move them into place. 47 typedef APInt APIntMoveTy; 48 #else 49 // Otherwise pass by const ref to save one copy. 50 typedef const APInt &APIntMoveTy; 51 #endif 52 53 public: 54 /// Initialize a full (the default) or empty set for the specified bit width. 55 /// 56 explicit ConstantRange(uint32_t BitWidth, bool isFullSet = true); 57 58 /// Initialize a range to hold the single specified value. 59 /// 60 ConstantRange(APIntMoveTy Value); 61 62 /// @brief Initialize a range of values explicitly. This will assert out if 63 /// Lower==Upper and Lower != Min or Max value for its type. It will also 64 /// assert out if the two APInt's are not the same bit width. 65 ConstantRange(APIntMoveTy Lower, APIntMoveTy Upper); 66 67 /// makeICmpRegion - Produce the smallest range that contains all values that 68 /// might satisfy the comparison specified by Pred when compared to any value 69 /// contained within Other. 70 /// 71 /// Solves for range X in 'for all x in X, there exists a y in Y such that 72 /// icmp op x, y is true'. Every value that might make the comparison true 73 /// is included in the resulting range. 74 static ConstantRange makeICmpRegion(unsigned Pred, 75 const ConstantRange &Other); 76 77 /// getLower - Return the lower value for this range... 78 /// 79 const APInt &getLower() const { return Lower; } 80 81 /// getUpper - Return the upper value for this range... 82 /// 83 const APInt &getUpper() const { return Upper; } 84 85 /// getBitWidth - get the bit width of this ConstantRange 86 /// 87 uint32_t getBitWidth() const { return Lower.getBitWidth(); } 88 89 /// isFullSet - Return true if this set contains all of the elements possible 90 /// for this data-type 91 /// 92 bool isFullSet() const; 93 94 /// isEmptySet - Return true if this set contains no members. 95 /// 96 bool isEmptySet() const; 97 98 /// isWrappedSet - Return true if this set wraps around the top of the range, 99 /// for example: [100, 8) 100 /// 101 bool isWrappedSet() const; 102 103 /// isSignWrappedSet - Return true if this set wraps around the INT_MIN of 104 /// its bitwidth, for example: i8 [120, 140). 105 /// 106 bool isSignWrappedSet() const; 107 108 /// contains - Return true if the specified value is in the set. 109 /// 110 bool contains(const APInt &Val) const; 111 112 /// contains - Return true if the other range is a subset of this one. 113 /// 114 bool contains(const ConstantRange &CR) const; 115 116 /// getSingleElement - If this set contains a single element, return it, 117 /// otherwise return null. 118 /// 119 const APInt *getSingleElement() const { 120 if (Upper == Lower + 1) 121 return &Lower; 122 return 0; 123 } 124 125 /// isSingleElement - Return true if this set contains exactly one member. 126 /// 127 bool isSingleElement() const { return getSingleElement() != 0; } 128 129 /// getSetSize - Return the number of elements in this set. 130 /// 131 APInt getSetSize() const; 132 133 /// getUnsignedMax - Return the largest unsigned value contained in the 134 /// ConstantRange. 135 /// 136 APInt getUnsignedMax() const; 137 138 /// getUnsignedMin - Return the smallest unsigned value contained in the 139 /// ConstantRange. 140 /// 141 APInt getUnsignedMin() const; 142 143 /// getSignedMax - Return the largest signed value contained in the 144 /// ConstantRange. 145 /// 146 APInt getSignedMax() const; 147 148 /// getSignedMin - Return the smallest signed value contained in the 149 /// ConstantRange. 150 /// 151 APInt getSignedMin() const; 152 153 /// operator== - Return true if this range is equal to another range. 154 /// 155 bool operator==(const ConstantRange &CR) const { 156 return Lower == CR.Lower && Upper == CR.Upper; 157 } 158 bool operator!=(const ConstantRange &CR) const { 159 return !operator==(CR); 160 } 161 162 /// subtract - Subtract the specified constant from the endpoints of this 163 /// constant range. 164 ConstantRange subtract(const APInt &CI) const; 165 166 /// \brief Subtract the specified range from this range (aka relative 167 /// complement of the sets). 168 ConstantRange difference(const ConstantRange &CR) const; 169 170 /// intersectWith - Return the range that results from the intersection of 171 /// this range with another range. The resultant range is guaranteed to 172 /// include all elements contained in both input ranges, and to have the 173 /// smallest possible set size that does so. Because there may be two 174 /// intersections with the same set size, A.intersectWith(B) might not 175 /// be equal to B.intersectWith(A). 176 /// 177 ConstantRange intersectWith(const ConstantRange &CR) const; 178 179 /// unionWith - Return the range that results from the union of this range 180 /// with another range. The resultant range is guaranteed to include the 181 /// elements of both sets, but may contain more. For example, [3, 9) union 182 /// [12,15) is [3, 15), which includes 9, 10, and 11, which were not included 183 /// in either set before. 184 /// 185 ConstantRange unionWith(const ConstantRange &CR) const; 186 187 /// zeroExtend - Return a new range in the specified integer type, which must 188 /// be strictly larger than the current type. The returned range will 189 /// correspond to the possible range of values if the source range had been 190 /// zero extended to BitWidth. 191 ConstantRange zeroExtend(uint32_t BitWidth) const; 192 193 /// signExtend - Return a new range in the specified integer type, which must 194 /// be strictly larger than the current type. The returned range will 195 /// correspond to the possible range of values if the source range had been 196 /// sign extended to BitWidth. 197 ConstantRange signExtend(uint32_t BitWidth) const; 198 199 /// truncate - Return a new range in the specified integer type, which must be 200 /// strictly smaller than the current type. The returned range will 201 /// correspond to the possible range of values if the source range had been 202 /// truncated to the specified type. 203 ConstantRange truncate(uint32_t BitWidth) const; 204 205 /// zextOrTrunc - make this range have the bit width given by \p BitWidth. The 206 /// value is zero extended, truncated, or left alone to make it that width. 207 ConstantRange zextOrTrunc(uint32_t BitWidth) const; 208 209 /// sextOrTrunc - make this range have the bit width given by \p BitWidth. The 210 /// value is sign extended, truncated, or left alone to make it that width. 211 ConstantRange sextOrTrunc(uint32_t BitWidth) const; 212 213 /// add - Return a new range representing the possible values resulting 214 /// from an addition of a value in this range and a value in \p Other. 215 ConstantRange add(const ConstantRange &Other) const; 216 217 /// sub - Return a new range representing the possible values resulting 218 /// from a subtraction of a value in this range and a value in \p Other. 219 ConstantRange sub(const ConstantRange &Other) const; 220 221 /// multiply - Return a new range representing the possible values resulting 222 /// from a multiplication of a value in this range and a value in \p Other. 223 /// TODO: This isn't fully implemented yet. 224 ConstantRange multiply(const ConstantRange &Other) const; 225 226 /// smax - Return a new range representing the possible values resulting 227 /// from a signed maximum of a value in this range and a value in \p Other. 228 ConstantRange smax(const ConstantRange &Other) const; 229 230 /// umax - Return a new range representing the possible values resulting 231 /// from an unsigned maximum of a value in this range and a value in \p Other. 232 ConstantRange umax(const ConstantRange &Other) const; 233 234 /// udiv - Return a new range representing the possible values resulting 235 /// from an unsigned division of a value in this range and a value in 236 /// \p Other. 237 ConstantRange udiv(const ConstantRange &Other) const; 238 239 /// binaryAnd - return a new range representing the possible values resulting 240 /// from a binary-and of a value in this range by a value in \p Other. 241 ConstantRange binaryAnd(const ConstantRange &Other) const; 242 243 /// binaryOr - return a new range representing the possible values resulting 244 /// from a binary-or of a value in this range by a value in \p Other. 245 ConstantRange binaryOr(const ConstantRange &Other) const; 246 247 /// shl - Return a new range representing the possible values resulting 248 /// from a left shift of a value in this range by a value in \p Other. 249 /// TODO: This isn't fully implemented yet. 250 ConstantRange shl(const ConstantRange &Other) const; 251 252 /// lshr - Return a new range representing the possible values resulting 253 /// from a logical right shift of a value in this range and a value in 254 /// \p Other. 255 ConstantRange lshr(const ConstantRange &Other) const; 256 257 /// inverse - Return a new range that is the logical not of the current set. 258 /// 259 ConstantRange inverse() const; 260 261 /// print - Print out the bounds to a stream... 262 /// 263 void print(raw_ostream &OS) const; 264 265 /// dump - Allow printing from a debugger easily... 266 /// 267 void dump() const; 268 }; 269 270 inline raw_ostream &operator<<(raw_ostream &OS, const ConstantRange &CR) { 271 CR.print(OS); 272 return OS; 273 } 274 275 } // End llvm namespace 276 277 #endif 278
