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"
44 class TargetLibraryInfo;
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);
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);
62 /// Given operands for an FAdd, see if we can fold the result. If not, this
64 Value *SimplifyFAddInst(Value *LHS, Value *RHS, FastMathFlags FMF,
65 const DataLayout *TD = nullptr,
66 const TargetLibraryInfo *TLI = nullptr,
67 const DominatorTree *DT = nullptr);
69 /// Given operands for an FSub, see if we can fold the result. If not, this
71 Value *SimplifyFSubInst(Value *LHS, Value *RHS, FastMathFlags FMF,
72 const DataLayout *TD = nullptr,
73 const TargetLibraryInfo *TLI = nullptr,
74 const DominatorTree *DT = nullptr);
76 /// Given operands for an FMul, see if we can fold the result. If not, this
78 Value *SimplifyFMulInst(Value *LHS, Value *RHS,
80 const DataLayout *TD = nullptr,
81 const TargetLibraryInfo *TLI = nullptr,
82 const DominatorTree *DT = nullptr);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
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);
212 //=== Helper functions for higher up the class hierarchy.
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);
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);
229 /// \brief Given a function and iterators over arguments, see if we can fold
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);
238 /// \brief Given a function and set of arguments, see if we can fold the
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);
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);
254 /// \brief Replace all uses of 'I' with 'SimpleV' and simplify the uses
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'.
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);
267 /// \brief Recursively attempt to simplify an instruction.
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
273 bool recursivelySimplifyInstruction(Instruction *I,
274 const DataLayout *TD = nullptr,
275 const TargetLibraryInfo *TLI = nullptr,
276 const DominatorTree *DT = nullptr);
277 } // end namespace llvm