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 = 0,
52 const TargetLibraryInfo *TLI = 0,
53 const DominatorTree *DT = 0);
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 = 0,
59 const TargetLibraryInfo *TLI = 0,
60 const DominatorTree *DT = 0);
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 = 0,
66 const TargetLibraryInfo *TLI = 0,
67 const DominatorTree *DT = 0);
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 = 0,
73 const TargetLibraryInfo *TLI = 0,
74 const DominatorTree *DT = 0);
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 = 0,
81 const TargetLibraryInfo *TLI = 0,
82 const DominatorTree *DT = 0);
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 = 0,
87 const TargetLibraryInfo *TLI = 0,
88 const DominatorTree *DT = 0);
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, const DataLayout *TD = 0,
93 const TargetLibraryInfo *TLI = 0,
94 const DominatorTree *DT = 0);
96 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
97 /// fold the result. If not, this returns null.
98 Value *SimplifyUDivInst(Value *LHS, Value *RHS, const DataLayout *TD = 0,
99 const TargetLibraryInfo *TLI = 0,
100 const DominatorTree *DT = 0);
102 /// SimplifyFDivInst - Given operands for an FDiv, see if we can
103 /// fold the result. If not, this returns null.
104 Value *SimplifyFDivInst(Value *LHS, Value *RHS, const DataLayout *TD = 0,
105 const TargetLibraryInfo *TLI = 0,
106 const DominatorTree *DT = 0);
108 /// SimplifySRemInst - Given operands for an SRem, see if we can
109 /// fold the result. If not, this returns null.
110 Value *SimplifySRemInst(Value *LHS, Value *RHS, const DataLayout *TD = 0,
111 const TargetLibraryInfo *TLI = 0,
112 const DominatorTree *DT = 0);
114 /// SimplifyURemInst - Given operands for a URem, see if we can
115 /// fold the result. If not, this returns null.
116 Value *SimplifyURemInst(Value *LHS, Value *RHS, const DataLayout *TD = 0,
117 const TargetLibraryInfo *TLI = 0,
118 const DominatorTree *DT = 0);
120 /// SimplifyFRemInst - Given operands for an FRem, see if we can
121 /// fold the result. If not, this returns null.
122 Value *SimplifyFRemInst(Value *LHS, Value *RHS, const DataLayout *TD = 0,
123 const TargetLibraryInfo *TLI = 0,
124 const DominatorTree *DT = 0);
126 /// SimplifyShlInst - Given operands for a Shl, see if we can
127 /// fold the result. If not, this returns null.
128 Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
129 const DataLayout *TD = 0,
130 const TargetLibraryInfo *TLI = 0,
131 const DominatorTree *DT = 0);
133 /// SimplifyLShrInst - Given operands for a LShr, see if we can
134 /// fold the result. If not, this returns null.
135 Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
136 const DataLayout *TD = 0,
137 const TargetLibraryInfo *TLI = 0,
138 const DominatorTree *DT = 0);
140 /// SimplifyAShrInst - Given operands for a AShr, see if we can
141 /// fold the result. If not, this returns null.
142 Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
143 const DataLayout *TD = 0,
144 const TargetLibraryInfo *TLI = 0,
145 const DominatorTree *DT = 0);
147 /// SimplifyAndInst - Given operands for an And, see if we can
148 /// fold the result. If not, this returns null.
149 Value *SimplifyAndInst(Value *LHS, Value *RHS, const DataLayout *TD = 0,
150 const TargetLibraryInfo *TLI = 0,
151 const DominatorTree *DT = 0);
153 /// SimplifyOrInst - Given operands for an Or, see if we can
154 /// fold the result. If not, this returns null.
155 Value *SimplifyOrInst(Value *LHS, Value *RHS, const DataLayout *TD = 0,
156 const TargetLibraryInfo *TLI = 0,
157 const DominatorTree *DT = 0);
159 /// SimplifyXorInst - Given operands for a Xor, see if we can
160 /// fold the result. If not, this returns null.
161 Value *SimplifyXorInst(Value *LHS, Value *RHS, const DataLayout *TD = 0,
162 const TargetLibraryInfo *TLI = 0,
163 const DominatorTree *DT = 0);
165 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
166 /// fold the result. If not, this returns null.
167 Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
168 const DataLayout *TD = 0,
169 const TargetLibraryInfo *TLI = 0,
170 const DominatorTree *DT = 0);
172 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
173 /// fold the result. If not, this returns null.
174 Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
175 const DataLayout *TD = 0,
176 const TargetLibraryInfo *TLI = 0,
177 const DominatorTree *DT = 0);
179 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
180 /// the result. If not, this returns null.
181 Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
182 const DataLayout *TD = 0,
183 const TargetLibraryInfo *TLI = 0,
184 const DominatorTree *DT = 0);
186 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
187 /// fold the result. If not, this returns null.
188 Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout *TD = 0,
189 const TargetLibraryInfo *TLI = 0,
190 const DominatorTree *DT = 0);
192 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
193 /// can fold the result. If not, this returns null.
194 Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
195 ArrayRef<unsigned> Idxs,
196 const DataLayout *TD = 0,
197 const TargetLibraryInfo *TLI = 0,
198 const DominatorTree *DT = 0);
200 /// SimplifyTruncInst - Given operands for an TruncInst, see if we can fold
201 /// the result. If not, this returns null.
202 Value *SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *TD = 0,
203 const TargetLibraryInfo *TLI = 0,
204 const DominatorTree *DT = 0);
206 //=== Helper functions for higher up the class hierarchy.
209 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
210 /// fold the result. If not, this returns null.
211 Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
212 const DataLayout *TD = 0,
213 const TargetLibraryInfo *TLI = 0,
214 const DominatorTree *DT = 0);
216 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
217 /// fold the result. If not, this returns null.
218 Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
219 const DataLayout *TD = 0,
220 const TargetLibraryInfo *TLI = 0,
221 const DominatorTree *DT = 0);
223 /// \brief Given a function and iterators over arguments, see if we can fold
226 /// If this call could not be simplified returns null.
227 Value *SimplifyCall(Value *V, User::op_iterator ArgBegin,
228 User::op_iterator ArgEnd, const DataLayout *TD = 0,
229 const TargetLibraryInfo *TLI = 0,
230 const DominatorTree *DT = 0);
232 /// \brief Given a function and set of arguments, see if we can fold the
235 /// If this call could not be simplified returns null.
236 Value *SimplifyCall(Value *V, ArrayRef<Value *> Args,
237 const DataLayout *TD = 0,
238 const TargetLibraryInfo *TLI = 0,
239 const DominatorTree *DT = 0);
241 /// SimplifyInstruction - See if we can compute a simplified version of this
242 /// instruction. If not, this returns null.
243 Value *SimplifyInstruction(Instruction *I, const DataLayout *TD = 0,
244 const TargetLibraryInfo *TLI = 0,
245 const DominatorTree *DT = 0);
248 /// \brief Replace all uses of 'I' with 'SimpleV' and simplify the uses
251 /// This first performs a normal RAUW of I with SimpleV. It then recursively
252 /// attempts to simplify those users updated by the operation. The 'I'
253 /// instruction must not be equal to the simplified value 'SimpleV'.
255 /// The function returns true if any simplifications were performed.
256 bool replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
257 const DataLayout *TD = 0,
258 const TargetLibraryInfo *TLI = 0,
259 const DominatorTree *DT = 0);
261 /// \brief Recursively attempt to simplify an instruction.
263 /// This routine uses SimplifyInstruction to simplify 'I', and if successful
264 /// replaces uses of 'I' with the simplified value. It then recurses on each
265 /// of the users impacted. It returns true if any simplifications were
267 bool recursivelySimplifyInstruction(Instruction *I,
268 const DataLayout *TD = 0,
269 const TargetLibraryInfo *TLI = 0,
270 const DominatorTree *DT = 0);
271 } // end namespace llvm