1 //===-- InstructionSimplify.h - Fold instrs into simpler forms --*- 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 // This file declares routines for folding instructions into simpler forms 11 // that do not require creating new instructions. This does constant folding 12 // ("add i32 1, 1" -> "2") but can also handle non-constant operands, either 13 // returning a constant ("and i32 %x, 0" -> "0") or an already existing value 14 // ("and i32 %x, %x" -> "%x"). If the simplification is also an instruction 15 // then it dominates the original instruction. 16 // 17 // These routines implicitly resolve undef uses. The easiest way to be safe when 18 // using these routines to obtain simplified values for existing instructions is 19 // to always replace all uses of the instructions with the resulting simplified 20 // values. This will prevent other code from seeing the same undef uses and 21 // resolving them to different values. 22 // 23 // These routines are designed to tolerate moderately incomplete IR, such as 24 // instructions that are not connected to basic blocks yet. However, they do 25 // require that all the IR that they encounter be valid. In particular, they 26 // require that all non-constant values be defined in the same function, and the 27 // same call context of that function (and not split between caller and callee 28 // contexts of a directly recursive call, for example). 29 // 30 //===----------------------------------------------------------------------===// 31 32 #ifndef LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H 33 #define LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H 34 35 #include "llvm/IR/User.h" 36 37 namespace llvm { 38 template<typename T> 39 class ArrayRef; 40 class AssumptionCache; 41 class DominatorTree; 42 class Instruction; 43 class DataLayout; 44 class FastMathFlags; 45 class TargetLibraryInfo; 46 class Type; 47 class Value; 48 49 /// SimplifyAddInst - Given operands for an Add, see if we can 50 /// fold the result. If not, this returns null. 51 Value *SimplifyAddInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW, 52 const DataLayout &DL, 53 const TargetLibraryInfo *TLI = nullptr, 54 const DominatorTree *DT = nullptr, 55 AssumptionCache *AC = nullptr, 56 const Instruction *CxtI = nullptr); 57 58 /// SimplifySubInst - Given operands for a Sub, see if we can 59 /// fold the result. If not, this returns null. 60 Value *SimplifySubInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW, 61 const DataLayout &DL, 62 const TargetLibraryInfo *TLI = nullptr, 63 const DominatorTree *DT = nullptr, 64 AssumptionCache *AC = nullptr, 65 const Instruction *CxtI = nullptr); 66 67 /// Given operands for an FAdd, see if we can fold the result. If not, this 68 /// returns null. 69 Value *SimplifyFAddInst(Value *LHS, Value *RHS, FastMathFlags FMF, 70 const DataLayout &DL, 71 const TargetLibraryInfo *TLI = nullptr, 72 const DominatorTree *DT = nullptr, 73 AssumptionCache *AC = nullptr, 74 const Instruction *CxtI = nullptr); 75 76 /// Given operands for an FSub, see if we can fold the result. If not, this 77 /// returns null. 78 Value *SimplifyFSubInst(Value *LHS, Value *RHS, FastMathFlags FMF, 79 const DataLayout &DL, 80 const TargetLibraryInfo *TLI = nullptr, 81 const DominatorTree *DT = nullptr, 82 AssumptionCache *AC = nullptr, 83 const Instruction *CxtI = nullptr); 84 85 /// Given operands for an FMul, see if we can fold the result. If not, this 86 /// returns null. 87 Value *SimplifyFMulInst(Value *LHS, Value *RHS, FastMathFlags FMF, 88 const DataLayout &DL, 89 const TargetLibraryInfo *TLI = nullptr, 90 const DominatorTree *DT = nullptr, 91 AssumptionCache *AC = nullptr, 92 const Instruction *CxtI = nullptr); 93 94 /// SimplifyMulInst - Given operands for a Mul, see if we can 95 /// fold the result. If not, this returns null. 96 Value *SimplifyMulInst(Value *LHS, Value *RHS, const DataLayout &DL, 97 const TargetLibraryInfo *TLI = nullptr, 98 const DominatorTree *DT = nullptr, 99 AssumptionCache *AC = nullptr, 100 const Instruction *CxtI = nullptr); 101 102 /// SimplifySDivInst - Given operands for an SDiv, see if we can 103 /// fold the result. If not, this returns null. 104 Value *SimplifySDivInst(Value *LHS, Value *RHS, const DataLayout &DL, 105 const TargetLibraryInfo *TLI = nullptr, 106 const DominatorTree *DT = nullptr, 107 AssumptionCache *AC = nullptr, 108 const Instruction *CxtI = nullptr); 109 110 /// SimplifyUDivInst - Given operands for a UDiv, see if we can 111 /// fold the result. If not, this returns null. 112 Value *SimplifyUDivInst(Value *LHS, Value *RHS, const DataLayout &DL, 113 const TargetLibraryInfo *TLI = nullptr, 114 const DominatorTree *DT = nullptr, 115 AssumptionCache *AC = nullptr, 116 const Instruction *CxtI = nullptr); 117 118 /// SimplifyFDivInst - Given operands for an FDiv, see if we can 119 /// fold the result. If not, this returns null. 120 Value *SimplifyFDivInst(Value *LHS, Value *RHS, FastMathFlags FMF, 121 const DataLayout &DL, 122 const TargetLibraryInfo *TLI = nullptr, 123 const DominatorTree *DT = nullptr, 124 AssumptionCache *AC = nullptr, 125 const Instruction *CxtI = nullptr); 126 127 /// SimplifySRemInst - Given operands for an SRem, see if we can 128 /// fold the result. If not, this returns null. 129 Value *SimplifySRemInst(Value *LHS, Value *RHS, const DataLayout &DL, 130 const TargetLibraryInfo *TLI = nullptr, 131 const DominatorTree *DT = nullptr, 132 AssumptionCache *AC = nullptr, 133 const Instruction *CxtI = nullptr); 134 135 /// SimplifyURemInst - Given operands for a URem, see if we can 136 /// fold the result. If not, this returns null. 137 Value *SimplifyURemInst(Value *LHS, Value *RHS, const DataLayout &DL, 138 const TargetLibraryInfo *TLI = nullptr, 139 const DominatorTree *DT = nullptr, 140 AssumptionCache *AC = nullptr, 141 const Instruction *CxtI = nullptr); 142 143 /// SimplifyFRemInst - Given operands for an FRem, see if we can 144 /// fold the result. If not, this returns null. 145 Value *SimplifyFRemInst(Value *LHS, Value *RHS, FastMathFlags FMF, 146 const DataLayout &DL, 147 const TargetLibraryInfo *TLI = nullptr, 148 const DominatorTree *DT = nullptr, 149 AssumptionCache *AC = nullptr, 150 const Instruction *CxtI = nullptr); 151 152 /// SimplifyShlInst - Given operands for a Shl, see if we can 153 /// fold the result. If not, this returns null. 154 Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, 155 const DataLayout &DL, 156 const TargetLibraryInfo *TLI = nullptr, 157 const DominatorTree *DT = nullptr, 158 AssumptionCache *AC = nullptr, 159 const Instruction *CxtI = nullptr); 160 161 /// SimplifyLShrInst - Given operands for a LShr, see if we can 162 /// fold the result. If not, this returns null. 163 Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact, 164 const DataLayout &DL, 165 const TargetLibraryInfo *TLI = nullptr, 166 const DominatorTree *DT = nullptr, 167 AssumptionCache *AC = nullptr, 168 const Instruction *CxtI = nullptr); 169 170 /// SimplifyAShrInst - Given operands for a AShr, see if we can 171 /// fold the result. If not, this returns null. 172 Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, 173 const DataLayout &DL, 174 const TargetLibraryInfo *TLI = nullptr, 175 const DominatorTree *DT = nullptr, 176 AssumptionCache *AC = nullptr, 177 const Instruction *CxtI = nullptr); 178 179 /// SimplifyAndInst - Given operands for an And, see if we can 180 /// fold the result. If not, this returns null. 181 Value *SimplifyAndInst(Value *LHS, Value *RHS, const DataLayout &DL, 182 const TargetLibraryInfo *TLI = nullptr, 183 const DominatorTree *DT = nullptr, 184 AssumptionCache *AC = nullptr, 185 const Instruction *CxtI = nullptr); 186 187 /// SimplifyOrInst - Given operands for an Or, see if we can 188 /// fold the result. If not, this returns null. 189 Value *SimplifyOrInst(Value *LHS, Value *RHS, const DataLayout &DL, 190 const TargetLibraryInfo *TLI = nullptr, 191 const DominatorTree *DT = nullptr, 192 AssumptionCache *AC = nullptr, 193 const Instruction *CxtI = nullptr); 194 195 /// SimplifyXorInst - Given operands for a Xor, see if we can 196 /// fold the result. If not, this returns null. 197 Value *SimplifyXorInst(Value *LHS, Value *RHS, const DataLayout &DL, 198 const TargetLibraryInfo *TLI = nullptr, 199 const DominatorTree *DT = nullptr, 200 AssumptionCache *AC = nullptr, 201 const Instruction *CxtI = nullptr); 202 203 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can 204 /// fold the result. If not, this returns null. 205 Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, 206 const DataLayout &DL, 207 const TargetLibraryInfo *TLI = nullptr, 208 const DominatorTree *DT = nullptr, 209 AssumptionCache *AC = nullptr, 210 Instruction *CxtI = nullptr); 211 212 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can 213 /// fold the result. If not, this returns null. 214 Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, 215 const DataLayout &DL, 216 const TargetLibraryInfo *TLI = nullptr, 217 const DominatorTree *DT = nullptr, 218 AssumptionCache *AC = nullptr, 219 const Instruction *CxtI = nullptr); 220 221 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold 222 /// the result. If not, this returns null. 223 Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal, 224 const DataLayout &DL, 225 const TargetLibraryInfo *TLI = nullptr, 226 const DominatorTree *DT = nullptr, 227 AssumptionCache *AC = nullptr, 228 const Instruction *CxtI = nullptr); 229 230 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can 231 /// fold the result. If not, this returns null. 232 Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout &DL, 233 const TargetLibraryInfo *TLI = nullptr, 234 const DominatorTree *DT = nullptr, 235 AssumptionCache *AC = nullptr, 236 const Instruction *CxtI = nullptr); 237 238 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we 239 /// can fold the result. If not, this returns null. 240 Value *SimplifyInsertValueInst(Value *Agg, Value *Val, 241 ArrayRef<unsigned> Idxs, const DataLayout &DL, 242 const TargetLibraryInfo *TLI = nullptr, 243 const DominatorTree *DT = nullptr, 244 AssumptionCache *AC = nullptr, 245 const Instruction *CxtI = nullptr); 246 247 /// SimplifyTruncInst - Given operands for an TruncInst, see if we can fold 248 /// the result. If not, this returns null. 249 Value *SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout &DL, 250 const TargetLibraryInfo *TLI = nullptr, 251 const DominatorTree *DT = nullptr, 252 AssumptionCache *AC = nullptr, 253 const Instruction *CxtI = nullptr); 254 255 //=== Helper functions for higher up the class hierarchy. 256 257 258 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can 259 /// fold the result. If not, this returns null. 260 Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS, 261 const DataLayout &DL, 262 const TargetLibraryInfo *TLI = nullptr, 263 const DominatorTree *DT = nullptr, 264 AssumptionCache *AC = nullptr, 265 const Instruction *CxtI = nullptr); 266 267 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can 268 /// fold the result. If not, this returns null. 269 Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, 270 const DataLayout &DL, 271 const TargetLibraryInfo *TLI = nullptr, 272 const DominatorTree *DT = nullptr, 273 AssumptionCache *AC = nullptr, 274 const Instruction *CxtI = nullptr); 275 /// SimplifyFPBinOp - Given operands for a BinaryOperator, see if we can 276 /// fold the result. If not, this returns null. 277 /// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the 278 /// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp. 279 Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS, 280 const FastMathFlags &FMF, const DataLayout &DL, 281 const TargetLibraryInfo *TLI = nullptr, 282 const DominatorTree *DT = nullptr, 283 AssumptionCache *AC = nullptr, 284 const Instruction *CxtI = nullptr); 285 286 /// \brief Given a function and iterators over arguments, see if we can fold 287 /// the result. 288 /// 289 /// If this call could not be simplified returns null. 290 Value *SimplifyCall(Value *V, User::op_iterator ArgBegin, 291 User::op_iterator ArgEnd, const DataLayout &DL, 292 const TargetLibraryInfo *TLI = nullptr, 293 const DominatorTree *DT = nullptr, 294 AssumptionCache *AC = nullptr, 295 const Instruction *CxtI = nullptr); 296 297 /// \brief Given a function and set of arguments, see if we can fold the 298 /// result. 299 /// 300 /// If this call could not be simplified returns null. 301 Value *SimplifyCall(Value *V, ArrayRef<Value *> Args, const DataLayout &DL, 302 const TargetLibraryInfo *TLI = nullptr, 303 const DominatorTree *DT = nullptr, 304 AssumptionCache *AC = nullptr, 305 const Instruction *CxtI = nullptr); 306 307 /// SimplifyInstruction - See if we can compute a simplified version of this 308 /// instruction. If not, this returns null. 309 Value *SimplifyInstruction(Instruction *I, const DataLayout &DL, 310 const TargetLibraryInfo *TLI = nullptr, 311 const DominatorTree *DT = nullptr, 312 AssumptionCache *AC = nullptr); 313 314 /// \brief Replace all uses of 'I' with 'SimpleV' and simplify the uses 315 /// recursively. 316 /// 317 /// This first performs a normal RAUW of I with SimpleV. It then recursively 318 /// attempts to simplify those users updated by the operation. The 'I' 319 /// instruction must not be equal to the simplified value 'SimpleV'. 320 /// 321 /// The function returns true if any simplifications were performed. 322 bool replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV, 323 const TargetLibraryInfo *TLI = nullptr, 324 const DominatorTree *DT = nullptr, 325 AssumptionCache *AC = nullptr); 326 327 /// \brief Recursively attempt to simplify an instruction. 328 /// 329 /// This routine uses SimplifyInstruction to simplify 'I', and if successful 330 /// replaces uses of 'I' with the simplified value. It then recurses on each 331 /// of the users impacted. It returns true if any simplifications were 332 /// performed. 333 bool recursivelySimplifyInstruction(Instruction *I, 334 const TargetLibraryInfo *TLI = nullptr, 335 const DominatorTree *DT = nullptr, 336 AssumptionCache *AC = nullptr); 337 } // end namespace llvm 338 339 #endif 340 341
