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 37namespace llvm { 38 template<typename T> 39 class ArrayRef; 40 class DominatorTree; 41 class Instruction; 42 class DataLayout; 43 class FastMathFlags; 44 class TargetLibraryInfo; 45 class Type; 46 class Value; 47 48 /// SimplifyAddInst - Given operands for an Add, see if we can 49 /// fold the result. If not, this returns null. 50 Value *SimplifyAddInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW, 51 const DataLayout *TD = nullptr, 52 const TargetLibraryInfo *TLI = nullptr, 53 const DominatorTree *DT = nullptr); 54 55 /// SimplifySubInst - Given operands for a Sub, see if we can 56 /// fold the result. If not, this returns null. 57 Value *SimplifySubInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW, 58 const DataLayout *TD = nullptr, 59 const TargetLibraryInfo *TLI = nullptr, 60 const DominatorTree *DT = nullptr); 61 62 /// Given operands for an FAdd, see if we can fold the result. If not, this 63 /// returns null. 64 Value *SimplifyFAddInst(Value *LHS, Value *RHS, FastMathFlags FMF, 65 const DataLayout *TD = nullptr, 66 const TargetLibraryInfo *TLI = nullptr, 67 const DominatorTree *DT = nullptr); 68 69 /// Given operands for an FSub, see if we can fold the result. If not, this 70 /// returns null. 71 Value *SimplifyFSubInst(Value *LHS, Value *RHS, FastMathFlags FMF, 72 const DataLayout *TD = nullptr, 73 const TargetLibraryInfo *TLI = nullptr, 74 const DominatorTree *DT = nullptr); 75 76 /// Given operands for an FMul, see if we can fold the result. If not, this 77 /// returns null. 78 Value *SimplifyFMulInst(Value *LHS, Value *RHS, 79 FastMathFlags FMF, 80 const DataLayout *TD = nullptr, 81 const TargetLibraryInfo *TLI = nullptr, 82 const DominatorTree *DT = nullptr); 83 84 /// SimplifyMulInst - Given operands for a Mul, see if we can 85 /// fold the result. If not, this returns null. 86 Value *SimplifyMulInst(Value *LHS, Value *RHS, const DataLayout *TD = nullptr, 87 const TargetLibraryInfo *TLI = nullptr, 88 const DominatorTree *DT = nullptr); 89 90 /// SimplifySDivInst - Given operands for an SDiv, see if we can 91 /// fold the result. If not, this returns null. 92 Value *SimplifySDivInst(Value *LHS, Value *RHS, 93 const DataLayout *TD = nullptr, 94 const TargetLibraryInfo *TLI = nullptr, 95 const DominatorTree *DT = nullptr); 96 97 /// SimplifyUDivInst - Given operands for a UDiv, see if we can 98 /// fold the result. If not, this returns null. 99 Value *SimplifyUDivInst(Value *LHS, Value *RHS, 100 const DataLayout *TD = nullptr, 101 const TargetLibraryInfo *TLI = nullptr, 102 const DominatorTree *DT = nullptr); 103 104 /// SimplifyFDivInst - Given operands for an FDiv, see if we can 105 /// fold the result. If not, this returns null. 106 Value *SimplifyFDivInst(Value *LHS, Value *RHS, 107 const DataLayout *TD = nullptr, 108 const TargetLibraryInfo *TLI = nullptr, 109 const DominatorTree *DT = nullptr); 110 111 /// SimplifySRemInst - Given operands for an SRem, see if we can 112 /// fold the result. If not, this returns null. 113 Value *SimplifySRemInst(Value *LHS, Value *RHS, 114 const DataLayout *TD = nullptr, 115 const TargetLibraryInfo *TLI = nullptr, 116 const DominatorTree *DT = nullptr); 117 118 /// SimplifyURemInst - Given operands for a URem, see if we can 119 /// fold the result. If not, this returns null. 120 Value *SimplifyURemInst(Value *LHS, Value *RHS, 121 const DataLayout *TD = nullptr, 122 const TargetLibraryInfo *TLI = nullptr, 123 const DominatorTree *DT = nullptr); 124 125 /// SimplifyFRemInst - Given operands for an FRem, see if we can 126 /// fold the result. If not, this returns null. 127 Value *SimplifyFRemInst(Value *LHS, Value *RHS, 128 const DataLayout *TD = nullptr, 129 const TargetLibraryInfo *TLI = nullptr, 130 const DominatorTree *DT = nullptr); 131 132 /// SimplifyShlInst - Given operands for a Shl, see if we can 133 /// fold the result. If not, this returns null. 134 Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, 135 const DataLayout *TD = nullptr, 136 const TargetLibraryInfo *TLI = nullptr, 137 const DominatorTree *DT = nullptr); 138 139 /// SimplifyLShrInst - Given operands for a LShr, see if we can 140 /// fold the result. If not, this returns null. 141 Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact, 142 const DataLayout *TD = nullptr, 143 const TargetLibraryInfo *TLI = nullptr, 144 const DominatorTree *DT = nullptr); 145 146 /// SimplifyAShrInst - Given operands for a AShr, see if we can 147 /// fold the result. If not, this returns null. 148 Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, 149 const DataLayout *TD = nullptr, 150 const TargetLibraryInfo *TLI = nullptr, 151 const DominatorTree *DT = nullptr); 152 153 /// SimplifyAndInst - Given operands for an And, see if we can 154 /// fold the result. If not, this returns null. 155 Value *SimplifyAndInst(Value *LHS, Value *RHS, const DataLayout *TD = nullptr, 156 const TargetLibraryInfo *TLI = nullptr, 157 const DominatorTree *DT = nullptr); 158 159 /// SimplifyOrInst - Given operands for an Or, see if we can 160 /// fold the result. If not, this returns null. 161 Value *SimplifyOrInst(Value *LHS, Value *RHS, const DataLayout *TD = nullptr, 162 const TargetLibraryInfo *TLI = nullptr, 163 const DominatorTree *DT = nullptr); 164 165 /// SimplifyXorInst - Given operands for a Xor, see if we can 166 /// fold the result. If not, this returns null. 167 Value *SimplifyXorInst(Value *LHS, Value *RHS, const DataLayout *TD = nullptr, 168 const TargetLibraryInfo *TLI = nullptr, 169 const DominatorTree *DT = nullptr); 170 171 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can 172 /// fold the result. If not, this returns null. 173 Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, 174 const DataLayout *TD = nullptr, 175 const TargetLibraryInfo *TLI = nullptr, 176 const DominatorTree *DT = nullptr); 177 178 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can 179 /// fold the result. If not, this returns null. 180 Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, 181 const DataLayout *TD = nullptr, 182 const TargetLibraryInfo *TLI = nullptr, 183 const DominatorTree *DT = nullptr); 184 185 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold 186 /// the result. If not, this returns null. 187 Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal, 188 const DataLayout *TD = nullptr, 189 const TargetLibraryInfo *TLI = nullptr, 190 const DominatorTree *DT = nullptr); 191 192 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can 193 /// fold the result. If not, this returns null. 194 Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout *TD = nullptr, 195 const TargetLibraryInfo *TLI = nullptr, 196 const DominatorTree *DT = nullptr); 197 198 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we 199 /// can fold the result. If not, this returns null. 200 Value *SimplifyInsertValueInst(Value *Agg, Value *Val, 201 ArrayRef<unsigned> Idxs, 202 const DataLayout *TD = nullptr, 203 const TargetLibraryInfo *TLI = nullptr, 204 const DominatorTree *DT = nullptr); 205 206 /// SimplifyTruncInst - Given operands for an TruncInst, see if we can fold 207 /// the result. If not, this returns null. 208 Value *SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *TD = nullptr, 209 const TargetLibraryInfo *TLI = nullptr, 210 const DominatorTree *DT = nullptr); 211 212 //=== Helper functions for higher up the class hierarchy. 213 214 215 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can 216 /// fold the result. If not, this returns null. 217 Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS, 218 const DataLayout *TD = nullptr, 219 const TargetLibraryInfo *TLI = nullptr, 220 const DominatorTree *DT = nullptr); 221 222 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can 223 /// fold the result. If not, this returns null. 224 Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, 225 const DataLayout *TD = nullptr, 226 const TargetLibraryInfo *TLI = nullptr, 227 const DominatorTree *DT = nullptr); 228 229 /// \brief Given a function and iterators over arguments, see if we can fold 230 /// the result. 231 /// 232 /// If this call could not be simplified returns null. 233 Value *SimplifyCall(Value *V, User::op_iterator ArgBegin, 234 User::op_iterator ArgEnd, const DataLayout *TD = nullptr, 235 const TargetLibraryInfo *TLI = nullptr, 236 const DominatorTree *DT = nullptr); 237 238 /// \brief Given a function and set of arguments, see if we can fold the 239 /// result. 240 /// 241 /// If this call could not be simplified returns null. 242 Value *SimplifyCall(Value *V, ArrayRef<Value *> Args, 243 const DataLayout *TD = nullptr, 244 const TargetLibraryInfo *TLI = nullptr, 245 const DominatorTree *DT = nullptr); 246 247 /// SimplifyInstruction - See if we can compute a simplified version of this 248 /// instruction. If not, this returns null. 249 Value *SimplifyInstruction(Instruction *I, const DataLayout *TD = nullptr, 250 const TargetLibraryInfo *TLI = nullptr, 251 const DominatorTree *DT = nullptr); 252 253 254 /// \brief Replace all uses of 'I' with 'SimpleV' and simplify the uses 255 /// recursively. 256 /// 257 /// This first performs a normal RAUW of I with SimpleV. It then recursively 258 /// attempts to simplify those users updated by the operation. The 'I' 259 /// instruction must not be equal to the simplified value 'SimpleV'. 260 /// 261 /// The function returns true if any simplifications were performed. 262 bool replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV, 263 const DataLayout *TD = nullptr, 264 const TargetLibraryInfo *TLI = nullptr, 265 const DominatorTree *DT = nullptr); 266 267 /// \brief Recursively attempt to simplify an instruction. 268 /// 269 /// This routine uses SimplifyInstruction to simplify 'I', and if successful 270 /// replaces uses of 'I' with the simplified value. It then recurses on each 271 /// of the users impacted. It returns true if any simplifications were 272 /// performed. 273 bool recursivelySimplifyInstruction(Instruction *I, 274 const DataLayout *TD = nullptr, 275 const TargetLibraryInfo *TLI = nullptr, 276 const DominatorTree *DT = nullptr); 277} // end namespace llvm 278 279#endif 280 281