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 TargetLibraryInfo;
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,
53 const TargetLibraryInfo *TLI = nullptr,
54 const DominatorTree *DT = nullptr,
55 AssumptionCache *AC = nullptr,
56 const Instruction *CxtI = nullptr);
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,
62 const TargetLibraryInfo *TLI = nullptr,
63 const DominatorTree *DT = nullptr,
64 AssumptionCache *AC = nullptr,
65 const Instruction *CxtI = nullptr);
67 /// Given operands for an FAdd, see if we can fold the result. If not, this
69 Value *SimplifyFAddInst(Value *LHS, Value *RHS, FastMathFlags FMF,
71 const TargetLibraryInfo *TLI = nullptr,
72 const DominatorTree *DT = nullptr,
73 AssumptionCache *AC = nullptr,
74 const Instruction *CxtI = nullptr);
76 /// Given operands for an FSub, see if we can fold the result. If not, this
78 Value *SimplifyFSubInst(Value *LHS, Value *RHS, FastMathFlags FMF,
80 const TargetLibraryInfo *TLI = nullptr,
81 const DominatorTree *DT = nullptr,
82 AssumptionCache *AC = nullptr,
83 const Instruction *CxtI = nullptr);
85 /// Given operands for an FMul, see if we can fold the result. If not, this
87 Value *SimplifyFMulInst(Value *LHS, Value *RHS, FastMathFlags FMF,
89 const TargetLibraryInfo *TLI = nullptr,
90 const DominatorTree *DT = nullptr,
91 AssumptionCache *AC = nullptr,
92 const Instruction *CxtI = nullptr);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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 FastMathFlags FMF, const DataLayout &DL,
216 const TargetLibraryInfo *TLI = nullptr,
217 const DominatorTree *DT = nullptr,
218 AssumptionCache *AC = nullptr,
219 const Instruction *CxtI = nullptr);
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);
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);
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);
247 /// \brief Given operands for an ExtractValueInst, see if we can fold the
248 /// result. If not, this returns null.
249 Value *SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs,
250 const DataLayout &DL,
251 const TargetLibraryInfo *TLI = nullptr,
252 const DominatorTree *DT = nullptr,
253 AssumptionCache *AC = nullptr,
254 const Instruction *CxtI = nullptr);
256 /// \brief Given operands for an ExtractElementInst, see if we can fold the
257 /// result. If not, this returns null.
258 Value *SimplifyExtractElementInst(Value *Vec, Value *Idx,
259 const DataLayout &DL,
260 const TargetLibraryInfo *TLI = nullptr,
261 const DominatorTree *DT = nullptr,
262 AssumptionCache *AC = nullptr,
263 const Instruction *CxtI = nullptr);
265 /// SimplifyTruncInst - Given operands for an TruncInst, see if we can fold
266 /// the result. If not, this returns null.
267 Value *SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout &DL,
268 const TargetLibraryInfo *TLI = nullptr,
269 const DominatorTree *DT = nullptr,
270 AssumptionCache *AC = nullptr,
271 const Instruction *CxtI = nullptr);
273 //=== Helper functions for higher up the class hierarchy.
276 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
277 /// fold the result. If not, this returns null.
278 Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
279 const DataLayout &DL,
280 const TargetLibraryInfo *TLI = nullptr,
281 const DominatorTree *DT = nullptr,
282 AssumptionCache *AC = nullptr,
283 const Instruction *CxtI = nullptr);
285 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
286 /// fold the result. If not, this returns null.
287 Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
288 const DataLayout &DL,
289 const TargetLibraryInfo *TLI = nullptr,
290 const DominatorTree *DT = nullptr,
291 AssumptionCache *AC = nullptr,
292 const Instruction *CxtI = nullptr);
293 /// SimplifyFPBinOp - Given operands for a BinaryOperator, see if we can
294 /// fold the result. If not, this returns null.
295 /// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the
296 /// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp.
297 Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
298 const FastMathFlags &FMF, const DataLayout &DL,
299 const TargetLibraryInfo *TLI = nullptr,
300 const DominatorTree *DT = nullptr,
301 AssumptionCache *AC = nullptr,
302 const Instruction *CxtI = nullptr);
304 /// \brief Given a function and iterators over arguments, see if we can fold
307 /// If this call could not be simplified returns null.
308 Value *SimplifyCall(Value *V, User::op_iterator ArgBegin,
309 User::op_iterator ArgEnd, const DataLayout &DL,
310 const TargetLibraryInfo *TLI = nullptr,
311 const DominatorTree *DT = nullptr,
312 AssumptionCache *AC = nullptr,
313 const Instruction *CxtI = nullptr);
315 /// \brief Given a function and set of arguments, see if we can fold the
318 /// If this call could not be simplified returns null.
319 Value *SimplifyCall(Value *V, ArrayRef<Value *> Args, const DataLayout &DL,
320 const TargetLibraryInfo *TLI = nullptr,
321 const DominatorTree *DT = nullptr,
322 AssumptionCache *AC = nullptr,
323 const Instruction *CxtI = nullptr);
325 /// SimplifyInstruction - See if we can compute a simplified version of this
326 /// instruction. If not, this returns null.
327 Value *SimplifyInstruction(Instruction *I, const DataLayout &DL,
328 const TargetLibraryInfo *TLI = nullptr,
329 const DominatorTree *DT = nullptr,
330 AssumptionCache *AC = nullptr);
332 /// \brief Replace all uses of 'I' with 'SimpleV' and simplify the uses
335 /// This first performs a normal RAUW of I with SimpleV. It then recursively
336 /// attempts to simplify those users updated by the operation. The 'I'
337 /// instruction must not be equal to the simplified value 'SimpleV'.
339 /// The function returns true if any simplifications were performed.
340 bool replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
341 const TargetLibraryInfo *TLI = nullptr,
342 const DominatorTree *DT = nullptr,
343 AssumptionCache *AC = nullptr);
345 /// \brief Recursively attempt to simplify an instruction.
347 /// This routine uses SimplifyInstruction to simplify 'I', and if successful
348 /// replaces uses of 'I' with the simplified value. It then recurses on each
349 /// of the users impacted. It returns true if any simplifications were
351 bool recursivelySimplifyInstruction(Instruction *I,
352 const TargetLibraryInfo *TLI = nullptr,
353 const DominatorTree *DT = nullptr,
354 AssumptionCache *AC = nullptr);
355 } // end namespace llvm