1 //===-- InstructionSimplify.h - Fold instrs into simpler forms --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
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.
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).
30 //===----------------------------------------------------------------------===//
32 #ifndef LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H
33 #define LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H
35 #include "llvm/IR/User.h"
40 class AssumptionCache;
45 class OptimizationRemarkEmitter;
46 class TargetLibraryInfo;
50 /// Given operands for an Add, fold the result or return null.
51 Value *SimplifyAddInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW,
53 const TargetLibraryInfo *TLI = nullptr,
54 const DominatorTree *DT = nullptr,
55 AssumptionCache *AC = nullptr,
56 const Instruction *CxtI = nullptr);
58 /// Given operands for a Sub, fold the result or return null.
59 Value *SimplifySubInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW,
61 const TargetLibraryInfo *TLI = nullptr,
62 const DominatorTree *DT = nullptr,
63 AssumptionCache *AC = nullptr,
64 const Instruction *CxtI = nullptr);
66 /// Given operands for an FAdd, fold the result or return null.
67 Value *SimplifyFAddInst(Value *LHS, Value *RHS, FastMathFlags FMF,
69 const TargetLibraryInfo *TLI = nullptr,
70 const DominatorTree *DT = nullptr,
71 AssumptionCache *AC = nullptr,
72 const Instruction *CxtI = nullptr);
74 /// Given operands for an FSub, fold the result or return null.
75 Value *SimplifyFSubInst(Value *LHS, Value *RHS, FastMathFlags FMF,
77 const TargetLibraryInfo *TLI = nullptr,
78 const DominatorTree *DT = nullptr,
79 AssumptionCache *AC = nullptr,
80 const Instruction *CxtI = nullptr);
82 /// Given operands for an FMul, fold the result or return null.
83 Value *SimplifyFMulInst(Value *LHS, Value *RHS, FastMathFlags FMF,
85 const TargetLibraryInfo *TLI = nullptr,
86 const DominatorTree *DT = nullptr,
87 AssumptionCache *AC = nullptr,
88 const Instruction *CxtI = nullptr);
90 /// Given operands for a Mul, fold the result or return null.
91 Value *SimplifyMulInst(Value *LHS, Value *RHS, const DataLayout &DL,
92 const TargetLibraryInfo *TLI = nullptr,
93 const DominatorTree *DT = nullptr,
94 AssumptionCache *AC = nullptr,
95 const Instruction *CxtI = nullptr);
97 /// Given operands for an SDiv, fold the result or return null.
98 Value *SimplifySDivInst(Value *LHS, Value *RHS, const DataLayout &DL,
99 const TargetLibraryInfo *TLI = nullptr,
100 const DominatorTree *DT = nullptr,
101 AssumptionCache *AC = nullptr,
102 const Instruction *CxtI = nullptr);
104 /// Given operands for a UDiv, fold the result or return null.
105 Value *SimplifyUDivInst(Value *LHS, Value *RHS, const DataLayout &DL,
106 const TargetLibraryInfo *TLI = nullptr,
107 const DominatorTree *DT = nullptr,
108 AssumptionCache *AC = nullptr,
109 const Instruction *CxtI = nullptr);
111 /// Given operands for an FDiv, fold the result or return null.
112 Value *SimplifyFDivInst(Value *LHS, Value *RHS, FastMathFlags FMF,
113 const DataLayout &DL,
114 const TargetLibraryInfo *TLI = nullptr,
115 const DominatorTree *DT = nullptr,
116 AssumptionCache *AC = nullptr,
117 const Instruction *CxtI = nullptr);
119 /// Given operands for an SRem, fold the result or return null.
120 Value *SimplifySRemInst(Value *LHS, Value *RHS, const DataLayout &DL,
121 const TargetLibraryInfo *TLI = nullptr,
122 const DominatorTree *DT = nullptr,
123 AssumptionCache *AC = nullptr,
124 const Instruction *CxtI = nullptr);
126 /// Given operands for a URem, fold the result or return null.
127 Value *SimplifyURemInst(Value *LHS, Value *RHS, const DataLayout &DL,
128 const TargetLibraryInfo *TLI = nullptr,
129 const DominatorTree *DT = nullptr,
130 AssumptionCache *AC = nullptr,
131 const Instruction *CxtI = nullptr);
133 /// Given operands for an FRem, fold the result or return null.
134 Value *SimplifyFRemInst(Value *LHS, Value *RHS, FastMathFlags FMF,
135 const DataLayout &DL,
136 const TargetLibraryInfo *TLI = nullptr,
137 const DominatorTree *DT = nullptr,
138 AssumptionCache *AC = nullptr,
139 const Instruction *CxtI = nullptr);
141 /// Given operands for a Shl, fold the result or return null.
142 Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
143 const DataLayout &DL,
144 const TargetLibraryInfo *TLI = nullptr,
145 const DominatorTree *DT = nullptr,
146 AssumptionCache *AC = nullptr,
147 const Instruction *CxtI = nullptr);
149 /// Given operands for a LShr, fold the result or return null.
150 Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
151 const DataLayout &DL,
152 const TargetLibraryInfo *TLI = nullptr,
153 const DominatorTree *DT = nullptr,
154 AssumptionCache *AC = nullptr,
155 const Instruction *CxtI = nullptr);
157 /// Given operands for a AShr, fold the result or return nulll.
158 Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
159 const DataLayout &DL,
160 const TargetLibraryInfo *TLI = nullptr,
161 const DominatorTree *DT = nullptr,
162 AssumptionCache *AC = nullptr,
163 const Instruction *CxtI = nullptr);
165 /// Given operands for an And, fold the result or return null.
166 Value *SimplifyAndInst(Value *LHS, Value *RHS, const DataLayout &DL,
167 const TargetLibraryInfo *TLI = nullptr,
168 const DominatorTree *DT = nullptr,
169 AssumptionCache *AC = nullptr,
170 const Instruction *CxtI = nullptr);
172 /// Given operands for an Or, fold the result or return null.
173 Value *SimplifyOrInst(Value *LHS, Value *RHS, const DataLayout &DL,
174 const TargetLibraryInfo *TLI = nullptr,
175 const DominatorTree *DT = nullptr,
176 AssumptionCache *AC = nullptr,
177 const Instruction *CxtI = nullptr);
179 /// Given operands for an Xor, fold the result or return null.
180 Value *SimplifyXorInst(Value *LHS, Value *RHS, const DataLayout &DL,
181 const TargetLibraryInfo *TLI = nullptr,
182 const DominatorTree *DT = nullptr,
183 AssumptionCache *AC = nullptr,
184 const Instruction *CxtI = nullptr);
186 /// Given operands for an ICmpInst, fold the result or return null.
187 Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
188 const DataLayout &DL,
189 const TargetLibraryInfo *TLI = nullptr,
190 const DominatorTree *DT = nullptr,
191 AssumptionCache *AC = nullptr,
192 const Instruction *CxtI = nullptr);
194 /// Given operands for an FCmpInst, fold the result or return null.
195 Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
196 FastMathFlags FMF, const DataLayout &DL,
197 const TargetLibraryInfo *TLI = nullptr,
198 const DominatorTree *DT = nullptr,
199 AssumptionCache *AC = nullptr,
200 const Instruction *CxtI = nullptr);
202 /// Given operands for a SelectInst, fold the result or return null.
203 Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
204 const DataLayout &DL,
205 const TargetLibraryInfo *TLI = nullptr,
206 const DominatorTree *DT = nullptr,
207 AssumptionCache *AC = nullptr,
208 const Instruction *CxtI = nullptr);
210 /// Given operands for a GetElementPtrInst, fold the result or return null.
211 Value *SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
212 const DataLayout &DL,
213 const TargetLibraryInfo *TLI = nullptr,
214 const DominatorTree *DT = nullptr,
215 AssumptionCache *AC = nullptr,
216 const Instruction *CxtI = nullptr);
218 /// Given operands for an InsertValueInst, fold the result or return null.
219 Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
220 ArrayRef<unsigned> Idxs, const DataLayout &DL,
221 const TargetLibraryInfo *TLI = nullptr,
222 const DominatorTree *DT = nullptr,
223 AssumptionCache *AC = nullptr,
224 const Instruction *CxtI = nullptr);
226 /// Given operands for an ExtractValueInst, fold the result or return null.
227 Value *SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs,
228 const DataLayout &DL,
229 const TargetLibraryInfo *TLI = nullptr,
230 const DominatorTree *DT = nullptr,
231 AssumptionCache *AC = nullptr,
232 const Instruction *CxtI = nullptr);
234 /// Given operands for an ExtractElementInst, fold the result or return null.
235 Value *SimplifyExtractElementInst(Value *Vec, Value *Idx,
236 const DataLayout &DL,
237 const TargetLibraryInfo *TLI = nullptr,
238 const DominatorTree *DT = nullptr,
239 AssumptionCache *AC = nullptr,
240 const Instruction *CxtI = nullptr);
242 /// Given operands for a CastInst, fold the result or return null.
243 Value *SimplifyCastInst(unsigned CastOpc, Value *Op, Type *Ty,
244 const DataLayout &DL,
245 const TargetLibraryInfo *TLI = nullptr,
246 const DominatorTree *DT = nullptr,
247 AssumptionCache *AC = nullptr,
248 const Instruction *CxtI = nullptr);
250 /// Given operands for a ShuffleVectorInst, fold the result or return null.
251 Value *SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask,
252 Type *RetTy, const DataLayout &DL,
253 const TargetLibraryInfo *TLI = nullptr,
254 const DominatorTree *DT = nullptr,
255 AssumptionCache *AC = nullptr,
256 const Instruction *CxtI = nullptr);
258 //=== Helper functions for higher up the class hierarchy.
261 /// Given operands for a CmpInst, fold the result or return null.
262 Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
263 const DataLayout &DL,
264 const TargetLibraryInfo *TLI = nullptr,
265 const DominatorTree *DT = nullptr,
266 AssumptionCache *AC = nullptr,
267 const Instruction *CxtI = nullptr);
269 /// Given operands for a BinaryOperator, fold the result or return null.
270 Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
271 const DataLayout &DL,
272 const TargetLibraryInfo *TLI = nullptr,
273 const DominatorTree *DT = nullptr,
274 AssumptionCache *AC = nullptr,
275 const Instruction *CxtI = nullptr);
277 /// Given operands for an FP BinaryOperator, fold the result or return null.
278 /// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the
279 /// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp.
280 Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
281 const FastMathFlags &FMF, const DataLayout &DL,
282 const TargetLibraryInfo *TLI = nullptr,
283 const DominatorTree *DT = nullptr,
284 AssumptionCache *AC = nullptr,
285 const Instruction *CxtI = nullptr);
287 /// Given a function and iterators over arguments, fold the result or return
289 Value *SimplifyCall(Value *V, User::op_iterator ArgBegin,
290 User::op_iterator ArgEnd, const DataLayout &DL,
291 const TargetLibraryInfo *TLI = nullptr,
292 const DominatorTree *DT = nullptr,
293 AssumptionCache *AC = nullptr,
294 const Instruction *CxtI = nullptr);
296 /// Given a function and set of arguments, fold the result or return null.
297 Value *SimplifyCall(Value *V, ArrayRef<Value *> Args, const DataLayout &DL,
298 const TargetLibraryInfo *TLI = nullptr,
299 const DominatorTree *DT = nullptr,
300 AssumptionCache *AC = nullptr,
301 const Instruction *CxtI = nullptr);
303 /// See if we can compute a simplified version of this instruction. If not,
305 Value *SimplifyInstruction(Instruction *I, const DataLayout &DL,
306 const TargetLibraryInfo *TLI = nullptr,
307 const DominatorTree *DT = nullptr,
308 AssumptionCache *AC = nullptr,
309 OptimizationRemarkEmitter *ORE = nullptr);
311 /// Replace all uses of 'I' with 'SimpleV' and simplify the uses recursively.
313 /// This first performs a normal RAUW of I with SimpleV. It then recursively
314 /// attempts to simplify those users updated by the operation. The 'I'
315 /// instruction must not be equal to the simplified value 'SimpleV'.
317 /// The function returns true if any simplifications were performed.
318 bool replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
319 const TargetLibraryInfo *TLI = nullptr,
320 const DominatorTree *DT = nullptr,
321 AssumptionCache *AC = nullptr);
323 /// Recursively attempt to simplify an instruction.
325 /// This routine uses SimplifyInstruction to simplify 'I', and if successful
326 /// replaces uses of 'I' with the simplified value. It then recurses on each
327 /// of the users impacted. It returns true if any simplifications were
329 bool recursivelySimplifyInstruction(Instruction *I,
330 const TargetLibraryInfo *TLI = nullptr,
331 const DominatorTree *DT = nullptr,
332 AssumptionCache *AC = nullptr);
333 } // end namespace llvm