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InstructionSimplify.cpp
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1 //===- InstructionSimplify.cpp - Fold instruction operands ----------------===//
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 implements 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"). All operands are assumed to have already been
15 // simplified: This is usually true and assuming it simplifies the logic (if
16 // they have not been simplified then results are correct but maybe suboptimal).
17 //
18 //===----------------------------------------------------------------------===//
19 
20 #define DEBUG_TYPE "instsimplify"
22 #include "llvm/ADT/SetVector.h"
23 #include "llvm/ADT/Statistic.h"
28 #include "llvm/IR/DataLayout.h"
29 #include "llvm/IR/GlobalAlias.h"
30 #include "llvm/IR/Operator.h"
35 using namespace llvm;
36 using namespace llvm::PatternMatch;
37 
38 enum { RecursionLimit = 3 };
39 
40 STATISTIC(NumExpand, "Number of expansions");
41 STATISTIC(NumFactor , "Number of factorizations");
42 STATISTIC(NumReassoc, "Number of reassociations");
43 
44 struct Query {
45  const DataLayout *TD;
47  const DominatorTree *DT;
48 
49  Query(const DataLayout *td, const TargetLibraryInfo *tli,
50  const DominatorTree *dt) : TD(td), TLI(tli), DT(dt) {}
51 };
52 
53 static Value *SimplifyAndInst(Value *, Value *, const Query &, unsigned);
54 static Value *SimplifyBinOp(unsigned, Value *, Value *, const Query &,
55  unsigned);
56 static Value *SimplifyCmpInst(unsigned, Value *, Value *, const Query &,
57  unsigned);
58 static Value *SimplifyOrInst(Value *, Value *, const Query &, unsigned);
59 static Value *SimplifyXorInst(Value *, Value *, const Query &, unsigned);
60 static Value *SimplifyTruncInst(Value *, Type *, const Query &, unsigned);
61 
62 /// getFalse - For a boolean type, or a vector of boolean type, return false, or
63 /// a vector with every element false, as appropriate for the type.
64 static Constant *getFalse(Type *Ty) {
65  assert(Ty->getScalarType()->isIntegerTy(1) &&
66  "Expected i1 type or a vector of i1!");
67  return Constant::getNullValue(Ty);
68 }
69 
70 /// getTrue - For a boolean type, or a vector of boolean type, return true, or
71 /// a vector with every element true, as appropriate for the type.
72 static Constant *getTrue(Type *Ty) {
73  assert(Ty->getScalarType()->isIntegerTy(1) &&
74  "Expected i1 type or a vector of i1!");
75  return Constant::getAllOnesValue(Ty);
76 }
77 
78 /// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
79 static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
80  Value *RHS) {
81  CmpInst *Cmp = dyn_cast<CmpInst>(V);
82  if (!Cmp)
83  return false;
84  CmpInst::Predicate CPred = Cmp->getPredicate();
85  Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
86  if (CPred == Pred && CLHS == LHS && CRHS == RHS)
87  return true;
88  return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
89  CRHS == LHS;
90 }
91 
92 /// ValueDominatesPHI - Does the given value dominate the specified phi node?
93 static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
95  if (!I)
96  // Arguments and constants dominate all instructions.
97  return true;
98 
99  // If we are processing instructions (and/or basic blocks) that have not been
100  // fully added to a function, the parent nodes may still be null. Simply
101  // return the conservative answer in these cases.
102  if (!I->getParent() || !P->getParent() || !I->getParent()->getParent())
103  return false;
104 
105  // If we have a DominatorTree then do a precise test.
106  if (DT) {
107  if (!DT->isReachableFromEntry(P->getParent()))
108  return true;
109  if (!DT->isReachableFromEntry(I->getParent()))
110  return false;
111  return DT->dominates(I, P);
112  }
113 
114  // Otherwise, if the instruction is in the entry block, and is not an invoke,
115  // then it obviously dominates all phi nodes.
116  if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
117  !isa<InvokeInst>(I))
118  return true;
119 
120  return false;
121 }
122 
123 /// ExpandBinOp - Simplify "A op (B op' C)" by distributing op over op', turning
124 /// it into "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
125 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
126 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
127 /// Returns the simplified value, or null if no simplification was performed.
128 static Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS,
129  unsigned OpcToExpand, const Query &Q,
130  unsigned MaxRecurse) {
131  Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand;
132  // Recursion is always used, so bail out at once if we already hit the limit.
133  if (!MaxRecurse--)
134  return 0;
135 
136  // Check whether the expression has the form "(A op' B) op C".
137  if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
138  if (Op0->getOpcode() == OpcodeToExpand) {
139  // It does! Try turning it into "(A op C) op' (B op C)".
140  Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
141  // Do "A op C" and "B op C" both simplify?
142  if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
143  if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
144  // They do! Return "L op' R" if it simplifies or is already available.
145  // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
146  if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
147  && L == B && R == A)) {
148  ++NumExpand;
149  return LHS;
150  }
151  // Otherwise return "L op' R" if it simplifies.
152  if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
153  ++NumExpand;
154  return V;
155  }
156  }
157  }
158 
159  // Check whether the expression has the form "A op (B op' C)".
160  if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
161  if (Op1->getOpcode() == OpcodeToExpand) {
162  // It does! Try turning it into "(A op B) op' (A op C)".
163  Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
164  // Do "A op B" and "A op C" both simplify?
165  if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
166  if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
167  // They do! Return "L op' R" if it simplifies or is already available.
168  // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
169  if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
170  && L == C && R == B)) {
171  ++NumExpand;
172  return RHS;
173  }
174  // Otherwise return "L op' R" if it simplifies.
175  if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
176  ++NumExpand;
177  return V;
178  }
179  }
180  }
181 
182  return 0;
183 }
184 
185 /// FactorizeBinOp - Simplify "LHS Opcode RHS" by factorizing out a common term
186 /// using the operation OpCodeToExtract. For example, when Opcode is Add and
187 /// OpCodeToExtract is Mul then this tries to turn "(A*B)+(A*C)" into "A*(B+C)".
188 /// Returns the simplified value, or null if no simplification was performed.
189 static Value *FactorizeBinOp(unsigned Opcode, Value *LHS, Value *RHS,
190  unsigned OpcToExtract, const Query &Q,
191  unsigned MaxRecurse) {
192  Instruction::BinaryOps OpcodeToExtract = (Instruction::BinaryOps)OpcToExtract;
193  // Recursion is always used, so bail out at once if we already hit the limit.
194  if (!MaxRecurse--)
195  return 0;
196 
199 
200  if (!Op0 || Op0->getOpcode() != OpcodeToExtract ||
201  !Op1 || Op1->getOpcode() != OpcodeToExtract)
202  return 0;
203 
204  // The expression has the form "(A op' B) op (C op' D)".
205  Value *A = Op0->getOperand(0), *B = Op0->getOperand(1);
206  Value *C = Op1->getOperand(0), *D = Op1->getOperand(1);
207 
208  // Use left distributivity, i.e. "X op' (Y op Z) = (X op' Y) op (X op' Z)".
209  // Does the instruction have the form "(A op' B) op (A op' D)" or, in the
210  // commutative case, "(A op' B) op (C op' A)"?
211  if (A == C || (Instruction::isCommutative(OpcodeToExtract) && A == D)) {
212  Value *DD = A == C ? D : C;
213  // Form "A op' (B op DD)" if it simplifies completely.
214  // Does "B op DD" simplify?
215  if (Value *V = SimplifyBinOp(Opcode, B, DD, Q, MaxRecurse)) {
216  // It does! Return "A op' V" if it simplifies or is already available.
217  // If V equals B then "A op' V" is just the LHS. If V equals DD then
218  // "A op' V" is just the RHS.
219  if (V == B || V == DD) {
220  ++NumFactor;
221  return V == B ? LHS : RHS;
222  }
223  // Otherwise return "A op' V" if it simplifies.
224  if (Value *W = SimplifyBinOp(OpcodeToExtract, A, V, Q, MaxRecurse)) {
225  ++NumFactor;
226  return W;
227  }
228  }
229  }
230 
231  // Use right distributivity, i.e. "(X op Y) op' Z = (X op' Z) op (Y op' Z)".
232  // Does the instruction have the form "(A op' B) op (C op' B)" or, in the
233  // commutative case, "(A op' B) op (B op' D)"?
234  if (B == D || (Instruction::isCommutative(OpcodeToExtract) && B == C)) {
235  Value *CC = B == D ? C : D;
236  // Form "(A op CC) op' B" if it simplifies completely..
237  // Does "A op CC" simplify?
238  if (Value *V = SimplifyBinOp(Opcode, A, CC, Q, MaxRecurse)) {
239  // It does! Return "V op' B" if it simplifies or is already available.
240  // If V equals A then "V op' B" is just the LHS. If V equals CC then
241  // "V op' B" is just the RHS.
242  if (V == A || V == CC) {
243  ++NumFactor;
244  return V == A ? LHS : RHS;
245  }
246  // Otherwise return "V op' B" if it simplifies.
247  if (Value *W = SimplifyBinOp(OpcodeToExtract, V, B, Q, MaxRecurse)) {
248  ++NumFactor;
249  return W;
250  }
251  }
252  }
253 
254  return 0;
255 }
256 
257 /// SimplifyAssociativeBinOp - Generic simplifications for associative binary
258 /// operations. Returns the simpler value, or null if none was found.
259 static Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS,
260  const Query &Q, unsigned MaxRecurse) {
262  assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
263 
264  // Recursion is always used, so bail out at once if we already hit the limit.
265  if (!MaxRecurse--)
266  return 0;
267 
270 
271  // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
272  if (Op0 && Op0->getOpcode() == Opcode) {
273  Value *A = Op0->getOperand(0);
274  Value *B = Op0->getOperand(1);
275  Value *C = RHS;
276 
277  // Does "B op C" simplify?
278  if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
279  // It does! Return "A op V" if it simplifies or is already available.
280  // If V equals B then "A op V" is just the LHS.
281  if (V == B) return LHS;
282  // Otherwise return "A op V" if it simplifies.
283  if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
284  ++NumReassoc;
285  return W;
286  }
287  }
288  }
289 
290  // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
291  if (Op1 && Op1->getOpcode() == Opcode) {
292  Value *A = LHS;
293  Value *B = Op1->getOperand(0);
294  Value *C = Op1->getOperand(1);
295 
296  // Does "A op B" simplify?
297  if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
298  // It does! Return "V op C" if it simplifies or is already available.
299  // If V equals B then "V op C" is just the RHS.
300  if (V == B) return RHS;
301  // Otherwise return "V op C" if it simplifies.
302  if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
303  ++NumReassoc;
304  return W;
305  }
306  }
307  }
308 
309  // The remaining transforms require commutativity as well as associativity.
310  if (!Instruction::isCommutative(Opcode))
311  return 0;
312 
313  // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
314  if (Op0 && Op0->getOpcode() == Opcode) {
315  Value *A = Op0->getOperand(0);
316  Value *B = Op0->getOperand(1);
317  Value *C = RHS;
318 
319  // Does "C op A" simplify?
320  if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
321  // It does! Return "V op B" if it simplifies or is already available.
322  // If V equals A then "V op B" is just the LHS.
323  if (V == A) return LHS;
324  // Otherwise return "V op B" if it simplifies.
325  if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
326  ++NumReassoc;
327  return W;
328  }
329  }
330  }
331 
332  // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
333  if (Op1 && Op1->getOpcode() == Opcode) {
334  Value *A = LHS;
335  Value *B = Op1->getOperand(0);
336  Value *C = Op1->getOperand(1);
337 
338  // Does "C op A" simplify?
339  if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
340  // It does! Return "B op V" if it simplifies or is already available.
341  // If V equals C then "B op V" is just the RHS.
342  if (V == C) return RHS;
343  // Otherwise return "B op V" if it simplifies.
344  if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
345  ++NumReassoc;
346  return W;
347  }
348  }
349  }
350 
351  return 0;
352 }
353 
354 /// ThreadBinOpOverSelect - In the case of a binary operation with a select
355 /// instruction as an operand, try to simplify the binop by seeing whether
356 /// evaluating it on both branches of the select results in the same value.
357 /// Returns the common value if so, otherwise returns null.
358 static Value *ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS,
359  const Query &Q, unsigned MaxRecurse) {
360  // Recursion is always used, so bail out at once if we already hit the limit.
361  if (!MaxRecurse--)
362  return 0;
363 
364  SelectInst *SI;
365  if (isa<SelectInst>(LHS)) {
366  SI = cast<SelectInst>(LHS);
367  } else {
368  assert(isa<SelectInst>(RHS) && "No select instruction operand!");
369  SI = cast<SelectInst>(RHS);
370  }
371 
372  // Evaluate the BinOp on the true and false branches of the select.
373  Value *TV;
374  Value *FV;
375  if (SI == LHS) {
376  TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
377  FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
378  } else {
379  TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
380  FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
381  }
382 
383  // If they simplified to the same value, then return the common value.
384  // If they both failed to simplify then return null.
385  if (TV == FV)
386  return TV;
387 
388  // If one branch simplified to undef, return the other one.
389  if (TV && isa<UndefValue>(TV))
390  return FV;
391  if (FV && isa<UndefValue>(FV))
392  return TV;
393 
394  // If applying the operation did not change the true and false select values,
395  // then the result of the binop is the select itself.
396  if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
397  return SI;
398 
399  // If one branch simplified and the other did not, and the simplified
400  // value is equal to the unsimplified one, return the simplified value.
401  // For example, select (cond, X, X & Z) & Z -> X & Z.
402  if ((FV && !TV) || (TV && !FV)) {
403  // Check that the simplified value has the form "X op Y" where "op" is the
404  // same as the original operation.
405  Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
406  if (Simplified && Simplified->getOpcode() == Opcode) {
407  // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
408  // We already know that "op" is the same as for the simplified value. See
409  // if the operands match too. If so, return the simplified value.
410  Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
411  Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
412  Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
413  if (Simplified->getOperand(0) == UnsimplifiedLHS &&
414  Simplified->getOperand(1) == UnsimplifiedRHS)
415  return Simplified;
416  if (Simplified->isCommutative() &&
417  Simplified->getOperand(1) == UnsimplifiedLHS &&
418  Simplified->getOperand(0) == UnsimplifiedRHS)
419  return Simplified;
420  }
421  }
422 
423  return 0;
424 }
425 
426 /// ThreadCmpOverSelect - In the case of a comparison with a select instruction,
427 /// try to simplify the comparison by seeing whether both branches of the select
428 /// result in the same value. Returns the common value if so, otherwise returns
429 /// null.
431  Value *RHS, const Query &Q,
432  unsigned MaxRecurse) {
433  // Recursion is always used, so bail out at once if we already hit the limit.
434  if (!MaxRecurse--)
435  return 0;
436 
437  // Make sure the select is on the LHS.
438  if (!isa<SelectInst>(LHS)) {
439  std::swap(LHS, RHS);
440  Pred = CmpInst::getSwappedPredicate(Pred);
441  }
442  assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
443  SelectInst *SI = cast<SelectInst>(LHS);
444  Value *Cond = SI->getCondition();
445  Value *TV = SI->getTrueValue();
446  Value *FV = SI->getFalseValue();
447 
448  // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
449  // Does "cmp TV, RHS" simplify?
450  Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
451  if (TCmp == Cond) {
452  // It not only simplified, it simplified to the select condition. Replace
453  // it with 'true'.
454  TCmp = getTrue(Cond->getType());
455  } else if (!TCmp) {
456  // It didn't simplify. However if "cmp TV, RHS" is equal to the select
457  // condition then we can replace it with 'true'. Otherwise give up.
458  if (!isSameCompare(Cond, Pred, TV, RHS))
459  return 0;
460  TCmp = getTrue(Cond->getType());
461  }
462 
463  // Does "cmp FV, RHS" simplify?
464  Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
465  if (FCmp == Cond) {
466  // It not only simplified, it simplified to the select condition. Replace
467  // it with 'false'.
468  FCmp = getFalse(Cond->getType());
469  } else if (!FCmp) {
470  // It didn't simplify. However if "cmp FV, RHS" is equal to the select
471  // condition then we can replace it with 'false'. Otherwise give up.
472  if (!isSameCompare(Cond, Pred, FV, RHS))
473  return 0;
474  FCmp = getFalse(Cond->getType());
475  }
476 
477  // If both sides simplified to the same value, then use it as the result of
478  // the original comparison.
479  if (TCmp == FCmp)
480  return TCmp;
481 
482  // The remaining cases only make sense if the select condition has the same
483  // type as the result of the comparison, so bail out if this is not so.
484  if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
485  return 0;
486  // If the false value simplified to false, then the result of the compare
487  // is equal to "Cond && TCmp". This also catches the case when the false
488  // value simplified to false and the true value to true, returning "Cond".
489  if (match(FCmp, m_Zero()))
490  if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
491  return V;
492  // If the true value simplified to true, then the result of the compare
493  // is equal to "Cond || FCmp".
494  if (match(TCmp, m_One()))
495  if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
496  return V;
497  // Finally, if the false value simplified to true and the true value to
498  // false, then the result of the compare is equal to "!Cond".
499  if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
500  if (Value *V =
501  SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
502  Q, MaxRecurse))
503  return V;
504 
505  return 0;
506 }
507 
508 /// ThreadBinOpOverPHI - In the case of a binary operation with an operand that
509 /// is a PHI instruction, try to simplify the binop by seeing whether evaluating
510 /// it on the incoming phi values yields the same result for every value. If so
511 /// returns the common value, otherwise returns null.
512 static Value *ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS,
513  const Query &Q, unsigned MaxRecurse) {
514  // Recursion is always used, so bail out at once if we already hit the limit.
515  if (!MaxRecurse--)
516  return 0;
517 
518  PHINode *PI;
519  if (isa<PHINode>(LHS)) {
520  PI = cast<PHINode>(LHS);
521  // Bail out if RHS and the phi may be mutually interdependent due to a loop.
522  if (!ValueDominatesPHI(RHS, PI, Q.DT))
523  return 0;
524  } else {
525  assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
526  PI = cast<PHINode>(RHS);
527  // Bail out if LHS and the phi may be mutually interdependent due to a loop.
528  if (!ValueDominatesPHI(LHS, PI, Q.DT))
529  return 0;
530  }
531 
532  // Evaluate the BinOp on the incoming phi values.
533  Value *CommonValue = 0;
534  for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
535  Value *Incoming = PI->getIncomingValue(i);
536  // If the incoming value is the phi node itself, it can safely be skipped.
537  if (Incoming == PI) continue;
538  Value *V = PI == LHS ?
539  SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
540  SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
541  // If the operation failed to simplify, or simplified to a different value
542  // to previously, then give up.
543  if (!V || (CommonValue && V != CommonValue))
544  return 0;
545  CommonValue = V;
546  }
547 
548  return CommonValue;
549 }
550 
551 /// ThreadCmpOverPHI - In the case of a comparison with a PHI instruction, try
552 /// try to simplify the comparison by seeing whether comparing with all of the
553 /// incoming phi values yields the same result every time. If so returns the
554 /// common result, otherwise returns null.
556  const Query &Q, unsigned MaxRecurse) {
557  // Recursion is always used, so bail out at once if we already hit the limit.
558  if (!MaxRecurse--)
559  return 0;
560 
561  // Make sure the phi is on the LHS.
562  if (!isa<PHINode>(LHS)) {
563  std::swap(LHS, RHS);
564  Pred = CmpInst::getSwappedPredicate(Pred);
565  }
566  assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
567  PHINode *PI = cast<PHINode>(LHS);
568 
569  // Bail out if RHS and the phi may be mutually interdependent due to a loop.
570  if (!ValueDominatesPHI(RHS, PI, Q.DT))
571  return 0;
572 
573  // Evaluate the BinOp on the incoming phi values.
574  Value *CommonValue = 0;
575  for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
576  Value *Incoming = PI->getIncomingValue(i);
577  // If the incoming value is the phi node itself, it can safely be skipped.
578  if (Incoming == PI) continue;
579  Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
580  // If the operation failed to simplify, or simplified to a different value
581  // to previously, then give up.
582  if (!V || (CommonValue && V != CommonValue))
583  return 0;
584  CommonValue = V;
585  }
586 
587  return CommonValue;
588 }
589 
590 /// SimplifyAddInst - Given operands for an Add, see if we can
591 /// fold the result. If not, this returns null.
592 static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
593  const Query &Q, unsigned MaxRecurse) {
594  if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
595  if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
596  Constant *Ops[] = { CLHS, CRHS };
597  return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(), Ops,
598  Q.TD, Q.TLI);
599  }
600 
601  // Canonicalize the constant to the RHS.
602  std::swap(Op0, Op1);
603  }
604 
605  // X + undef -> undef
606  if (match(Op1, m_Undef()))
607  return Op1;
608 
609  // X + 0 -> X
610  if (match(Op1, m_Zero()))
611  return Op0;
612 
613  // X + (Y - X) -> Y
614  // (Y - X) + X -> Y
615  // Eg: X + -X -> 0
616  Value *Y = 0;
617  if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
618  match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
619  return Y;
620 
621  // X + ~X -> -1 since ~X = -X-1
622  if (match(Op0, m_Not(m_Specific(Op1))) ||
623  match(Op1, m_Not(m_Specific(Op0))))
624  return Constant::getAllOnesValue(Op0->getType());
625 
626  /// i1 add -> xor.
627  if (MaxRecurse && Op0->getType()->isIntegerTy(1))
628  if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
629  return V;
630 
631  // Try some generic simplifications for associative operations.
632  if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
633  MaxRecurse))
634  return V;
635 
636  // Mul distributes over Add. Try some generic simplifications based on this.
637  if (Value *V = FactorizeBinOp(Instruction::Add, Op0, Op1, Instruction::Mul,
638  Q, MaxRecurse))
639  return V;
640 
641  // Threading Add over selects and phi nodes is pointless, so don't bother.
642  // Threading over the select in "A + select(cond, B, C)" means evaluating
643  // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
644  // only if B and C are equal. If B and C are equal then (since we assume
645  // that operands have already been simplified) "select(cond, B, C)" should
646  // have been simplified to the common value of B and C already. Analysing
647  // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
648  // for threading over phi nodes.
649 
650  return 0;
651 }
652 
653 Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
654  const DataLayout *TD, const TargetLibraryInfo *TLI,
655  const DominatorTree *DT) {
656  return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
658 }
659 
660 /// \brief Compute the base pointer and cumulative constant offsets for V.
661 ///
662 /// This strips all constant offsets off of V, leaving it the base pointer, and
663 /// accumulates the total constant offset applied in the returned constant. It
664 /// returns 0 if V is not a pointer, and returns the constant '0' if there are
665 /// no constant offsets applied.
666 ///
667 /// This is very similar to GetPointerBaseWithConstantOffset except it doesn't
668 /// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc.
669 /// folding.
671  Value *&V,
672  bool AllowNonInbounds = false) {
673  assert(V->getType()->getScalarType()->isPointerTy());
674 
675  // Without DataLayout, just be conservative for now. Theoretically, more could
676  // be done in this case.
677  if (!TD)
678  return ConstantInt::get(IntegerType::get(V->getContext(), 64), 0);
679 
680  Type *IntPtrTy = TD->getIntPtrType(V->getType())->getScalarType();
681  APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());
682 
683  // Even though we don't look through PHI nodes, we could be called on an
684  // instruction in an unreachable block, which may be on a cycle.
685  SmallPtrSet<Value *, 4> Visited;
686  Visited.insert(V);
687  do {
688  if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
689  if ((!AllowNonInbounds && !GEP->isInBounds()) ||
690  !GEP->accumulateConstantOffset(*TD, Offset))
691  break;
692  V = GEP->getPointerOperand();
693  } else if (Operator::getOpcode(V) == Instruction::BitCast) {
694  V = cast<Operator>(V)->getOperand(0);
695  } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
696  if (GA->mayBeOverridden())
697  break;
698  V = GA->getAliasee();
699  } else {
700  break;
701  }
702  assert(V->getType()->getScalarType()->isPointerTy() &&
703  "Unexpected operand type!");
704  } while (Visited.insert(V));
705 
706  Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
707  if (V->getType()->isVectorTy())
709  OffsetIntPtr);
710  return OffsetIntPtr;
711 }
712 
713 /// \brief Compute the constant difference between two pointer values.
714 /// If the difference is not a constant, returns zero.
716  Value *LHS, Value *RHS) {
717  Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS);
718  Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS);
719 
720  // If LHS and RHS are not related via constant offsets to the same base
721  // value, there is nothing we can do here.
722  if (LHS != RHS)
723  return 0;
724 
725  // Otherwise, the difference of LHS - RHS can be computed as:
726  // LHS - RHS
727  // = (LHSOffset + Base) - (RHSOffset + Base)
728  // = LHSOffset - RHSOffset
729  return ConstantExpr::getSub(LHSOffset, RHSOffset);
730 }
731 
732 /// SimplifySubInst - Given operands for a Sub, see if we can
733 /// fold the result. If not, this returns null.
734 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
735  const Query &Q, unsigned MaxRecurse) {
736  if (Constant *CLHS = dyn_cast<Constant>(Op0))
737  if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
738  Constant *Ops[] = { CLHS, CRHS };
739  return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(),
740  Ops, Q.TD, Q.TLI);
741  }
742 
743  // X - undef -> undef
744  // undef - X -> undef
745  if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
746  return UndefValue::get(Op0->getType());
747 
748  // X - 0 -> X
749  if (match(Op1, m_Zero()))
750  return Op0;
751 
752  // X - X -> 0
753  if (Op0 == Op1)
754  return Constant::getNullValue(Op0->getType());
755 
756  // (X*2) - X -> X
757  // (X<<1) - X -> X
758  Value *X = 0;
759  if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) ||
760  match(Op0, m_Shl(m_Specific(Op1), m_One())))
761  return Op1;
762 
763  // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
764  // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
765  Value *Y = 0, *Z = Op1;
766  if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
767  // See if "V === Y - Z" simplifies.
768  if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
769  // It does! Now see if "X + V" simplifies.
770  if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
771  // It does, we successfully reassociated!
772  ++NumReassoc;
773  return W;
774  }
775  // See if "V === X - Z" simplifies.
776  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
777  // It does! Now see if "Y + V" simplifies.
778  if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
779  // It does, we successfully reassociated!
780  ++NumReassoc;
781  return W;
782  }
783  }
784 
785  // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
786  // For example, X - (X + 1) -> -1
787  X = Op0;
788  if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
789  // See if "V === X - Y" simplifies.
790  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
791  // It does! Now see if "V - Z" simplifies.
792  if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
793  // It does, we successfully reassociated!
794  ++NumReassoc;
795  return W;
796  }
797  // See if "V === X - Z" simplifies.
798  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
799  // It does! Now see if "V - Y" simplifies.
800  if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
801  // It does, we successfully reassociated!
802  ++NumReassoc;
803  return W;
804  }
805  }
806 
807  // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
808  // For example, X - (X - Y) -> Y.
809  Z = Op0;
810  if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
811  // See if "V === Z - X" simplifies.
812  if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
813  // It does! Now see if "V + Y" simplifies.
814  if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
815  // It does, we successfully reassociated!
816  ++NumReassoc;
817  return W;
818  }
819 
820  // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
821  if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
822  match(Op1, m_Trunc(m_Value(Y))))
823  if (X->getType() == Y->getType())
824  // See if "V === X - Y" simplifies.
825  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
826  // It does! Now see if "trunc V" simplifies.
827  if (Value *W = SimplifyTruncInst(V, Op0->getType(), Q, MaxRecurse-1))
828  // It does, return the simplified "trunc V".
829  return W;
830 
831  // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
832  if (match(Op0, m_PtrToInt(m_Value(X))) &&
833  match(Op1, m_PtrToInt(m_Value(Y))))
834  if (Constant *Result = computePointerDifference(Q.TD, X, Y))
835  return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
836 
837  // Mul distributes over Sub. Try some generic simplifications based on this.
838  if (Value *V = FactorizeBinOp(Instruction::Sub, Op0, Op1, Instruction::Mul,
839  Q, MaxRecurse))
840  return V;
841 
842  // i1 sub -> xor.
843  if (MaxRecurse && Op0->getType()->isIntegerTy(1))
844  if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
845  return V;
846 
847  // Threading Sub over selects and phi nodes is pointless, so don't bother.
848  // Threading over the select in "A - select(cond, B, C)" means evaluating
849  // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
850  // only if B and C are equal. If B and C are equal then (since we assume
851  // that operands have already been simplified) "select(cond, B, C)" should
852  // have been simplified to the common value of B and C already. Analysing
853  // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
854  // for threading over phi nodes.
855 
856  return 0;
857 }
858 
859 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
860  const DataLayout *TD, const TargetLibraryInfo *TLI,
861  const DominatorTree *DT) {
862  return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
864 }
865 
866 /// Given operands for an FAdd, see if we can fold the result. If not, this
867 /// returns null.
869  const Query &Q, unsigned MaxRecurse) {
870  if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
871  if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
872  Constant *Ops[] = { CLHS, CRHS };
873  return ConstantFoldInstOperands(Instruction::FAdd, CLHS->getType(),
874  Ops, Q.TD, Q.TLI);
875  }
876 
877  // Canonicalize the constant to the RHS.
878  std::swap(Op0, Op1);
879  }
880 
881  // fadd X, -0 ==> X
882  if (match(Op1, m_NegZero()))
883  return Op0;
884 
885  // fadd X, 0 ==> X, when we know X is not -0
886  if (match(Op1, m_Zero()) &&
887  (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
888  return Op0;
889 
890  // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
891  // where nnan and ninf have to occur at least once somewhere in this
892  // expression
893  Value *SubOp = 0;
894  if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
895  SubOp = Op1;
896  else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
897  SubOp = Op0;
898  if (SubOp) {
899  Instruction *FSub = cast<Instruction>(SubOp);
900  if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
901  (FMF.noInfs() || FSub->hasNoInfs()))
902  return Constant::getNullValue(Op0->getType());
903  }
904 
905  return 0;
906 }
907 
908 /// Given operands for an FSub, see if we can fold the result. If not, this
909 /// returns null.
911  const Query &Q, unsigned MaxRecurse) {
912  if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
913  if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
914  Constant *Ops[] = { CLHS, CRHS };
915  return ConstantFoldInstOperands(Instruction::FSub, CLHS->getType(),
916  Ops, Q.TD, Q.TLI);
917  }
918  }
919 
920  // fsub X, 0 ==> X
921  if (match(Op1, m_Zero()))
922  return Op0;
923 
924  // fsub X, -0 ==> X, when we know X is not -0
925  if (match(Op1, m_NegZero()) &&
926  (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
927  return Op0;
928 
929  // fsub 0, (fsub -0.0, X) ==> X
930  Value *X;
931  if (match(Op0, m_AnyZero())) {
932  if (match(Op1, m_FSub(m_NegZero(), m_Value(X))))
933  return X;
934  if (FMF.noSignedZeros() && match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
935  return X;
936  }
937 
938  // fsub nnan ninf x, x ==> 0.0
939  if (FMF.noNaNs() && FMF.noInfs() && Op0 == Op1)
940  return Constant::getNullValue(Op0->getType());
941 
942  return 0;
943 }
944 
945 /// Given the operands for an FMul, see if we can fold the result
946 static Value *SimplifyFMulInst(Value *Op0, Value *Op1,
947  FastMathFlags FMF,
948  const Query &Q,
949  unsigned MaxRecurse) {
950  if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
951  if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
952  Constant *Ops[] = { CLHS, CRHS };
953  return ConstantFoldInstOperands(Instruction::FMul, CLHS->getType(),
954  Ops, Q.TD, Q.TLI);
955  }
956 
957  // Canonicalize the constant to the RHS.
958  std::swap(Op0, Op1);
959  }
960 
961  // fmul X, 1.0 ==> X
962  if (match(Op1, m_FPOne()))
963  return Op0;
964 
965  // fmul nnan nsz X, 0 ==> 0
966  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
967  return Op1;
968 
969  return 0;
970 }
971 
972 /// SimplifyMulInst - Given operands for a Mul, see if we can
973 /// fold the result. If not, this returns null.
974 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const Query &Q,
975  unsigned MaxRecurse) {
976  if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
977  if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
978  Constant *Ops[] = { CLHS, CRHS };
979  return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(),
980  Ops, Q.TD, Q.TLI);
981  }
982 
983  // Canonicalize the constant to the RHS.
984  std::swap(Op0, Op1);
985  }
986 
987  // X * undef -> 0
988  if (match(Op1, m_Undef()))
989  return Constant::getNullValue(Op0->getType());
990 
991  // X * 0 -> 0
992  if (match(Op1, m_Zero()))
993  return Op1;
994 
995  // X * 1 -> X
996  if (match(Op1, m_One()))
997  return Op0;
998 
999  // (X / Y) * Y -> X if the division is exact.
1000  Value *X = 0;
1001  if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
1002  match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
1003  return X;
1004 
1005  // i1 mul -> and.
1006  if (MaxRecurse && Op0->getType()->isIntegerTy(1))
1007  if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
1008  return V;
1009 
1010  // Try some generic simplifications for associative operations.
1011  if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
1012  MaxRecurse))
1013  return V;
1014 
1015  // Mul distributes over Add. Try some generic simplifications based on this.
1016  if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
1017  Q, MaxRecurse))
1018  return V;
1019 
1020  // If the operation is with the result of a select instruction, check whether
1021  // operating on either branch of the select always yields the same value.
1022  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1023  if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
1024  MaxRecurse))
1025  return V;
1026 
1027  // If the operation is with the result of a phi instruction, check whether
1028  // operating on all incoming values of the phi always yields the same value.
1029  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1030  if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
1031  MaxRecurse))
1032  return V;
1033 
1034  return 0;
1035 }
1036 
1038  const DataLayout *TD, const TargetLibraryInfo *TLI,
1039  const DominatorTree *DT) {
1040  return ::SimplifyFAddInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1041 }
1042 
1044  const DataLayout *TD, const TargetLibraryInfo *TLI,
1045  const DominatorTree *DT) {
1046  return ::SimplifyFSubInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1047 }
1048 
1050  FastMathFlags FMF,
1051  const DataLayout *TD,
1052  const TargetLibraryInfo *TLI,
1053  const DominatorTree *DT) {
1054  return ::SimplifyFMulInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1055 }
1056 
1058  const TargetLibraryInfo *TLI,
1059  const DominatorTree *DT) {
1060  return ::SimplifyMulInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1061 }
1062 
1063 /// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can
1064 /// fold the result. If not, this returns null.
1066  const Query &Q, unsigned MaxRecurse) {
1067  if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1068  if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1069  Constant *Ops[] = { C0, C1 };
1070  return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1071  }
1072  }
1073 
1074  bool isSigned = Opcode == Instruction::SDiv;
1075 
1076  // X / undef -> undef
1077  if (match(Op1, m_Undef()))
1078  return Op1;
1079 
1080  // undef / X -> 0
1081  if (match(Op0, m_Undef()))
1082  return Constant::getNullValue(Op0->getType());
1083 
1084  // 0 / X -> 0, we don't need to preserve faults!
1085  if (match(Op0, m_Zero()))
1086  return Op0;
1087 
1088  // X / 1 -> X
1089  if (match(Op1, m_One()))
1090  return Op0;
1091 
1092  if (Op0->getType()->isIntegerTy(1))
1093  // It can't be division by zero, hence it must be division by one.
1094  return Op0;
1095 
1096  // X / X -> 1
1097  if (Op0 == Op1)
1098  return ConstantInt::get(Op0->getType(), 1);
1099 
1100  // (X * Y) / Y -> X if the multiplication does not overflow.
1101  Value *X = 0, *Y = 0;
1102  if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
1103  if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
1104  OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
1105  // If the Mul knows it does not overflow, then we are good to go.
1106  if ((isSigned && Mul->hasNoSignedWrap()) ||
1107  (!isSigned && Mul->hasNoUnsignedWrap()))
1108  return X;
1109  // If X has the form X = A / Y then X * Y cannot overflow.
1110  if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
1111  if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
1112  return X;
1113  }
1114 
1115  // (X rem Y) / Y -> 0
1116  if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1117  (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1118  return Constant::getNullValue(Op0->getType());
1119 
1120  // If the operation is with the result of a select instruction, check whether
1121  // operating on either branch of the select always yields the same value.
1122  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1123  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1124  return V;
1125 
1126  // If the operation is with the result of a phi instruction, check whether
1127  // operating on all incoming values of the phi always yields the same value.
1128  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1129  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1130  return V;
1131 
1132  return 0;
1133 }
1134 
1135 /// SimplifySDivInst - Given operands for an SDiv, see if we can
1136 /// fold the result. If not, this returns null.
1137 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const Query &Q,
1138  unsigned MaxRecurse) {
1139  if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse))
1140  return V;
1141 
1142  return 0;
1143 }
1144 
1146  const TargetLibraryInfo *TLI,
1147  const DominatorTree *DT) {
1148  return ::SimplifySDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1149 }
1150 
1151 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
1152 /// fold the result. If not, this returns null.
1153 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q,
1154  unsigned MaxRecurse) {
1155  if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
1156  return V;
1157 
1158  return 0;
1159 }
1160 
1162  const TargetLibraryInfo *TLI,
1163  const DominatorTree *DT) {
1164  return ::SimplifyUDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1165 }
1166 
1167 static Value *SimplifyFDivInst(Value *Op0, Value *Op1, const Query &Q,
1168  unsigned) {
1169  // undef / X -> undef (the undef could be a snan).
1170  if (match(Op0, m_Undef()))
1171  return Op0;
1172 
1173  // X / undef -> undef
1174  if (match(Op1, m_Undef()))
1175  return Op1;
1176 
1177  return 0;
1178 }
1179 
1181  const TargetLibraryInfo *TLI,
1182  const DominatorTree *DT) {
1183  return ::SimplifyFDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1184 }
1185 
1186 /// SimplifyRem - Given operands for an SRem or URem, see if we can
1187 /// fold the result. If not, this returns null.
1189  const Query &Q, unsigned MaxRecurse) {
1190  if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1191  if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1192  Constant *Ops[] = { C0, C1 };
1193  return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1194  }
1195  }
1196 
1197  // X % undef -> undef
1198  if (match(Op1, m_Undef()))
1199  return Op1;
1200 
1201  // undef % X -> 0
1202  if (match(Op0, m_Undef()))
1203  return Constant::getNullValue(Op0->getType());
1204 
1205  // 0 % X -> 0, we don't need to preserve faults!
1206  if (match(Op0, m_Zero()))
1207  return Op0;
1208 
1209  // X % 0 -> undef, we don't need to preserve faults!
1210  if (match(Op1, m_Zero()))
1211  return UndefValue::get(Op0->getType());
1212 
1213  // X % 1 -> 0
1214  if (match(Op1, m_One()))
1215  return Constant::getNullValue(Op0->getType());
1216 
1217  if (Op0->getType()->isIntegerTy(1))
1218  // It can't be remainder by zero, hence it must be remainder by one.
1219  return Constant::getNullValue(Op0->getType());
1220 
1221  // X % X -> 0
1222  if (Op0 == Op1)
1223  return Constant::getNullValue(Op0->getType());
1224 
1225  // If the operation is with the result of a select instruction, check whether
1226  // operating on either branch of the select always yields the same value.
1227  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1228  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1229  return V;
1230 
1231  // If the operation is with the result of a phi instruction, check whether
1232  // operating on all incoming values of the phi always yields the same value.
1233  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1234  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1235  return V;
1236 
1237  return 0;
1238 }
1239 
1240 /// SimplifySRemInst - Given operands for an SRem, see if we can
1241 /// fold the result. If not, this returns null.
1242 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q,
1243  unsigned MaxRecurse) {
1244  if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
1245  return V;
1246 
1247  return 0;
1248 }
1249 
1251  const TargetLibraryInfo *TLI,
1252  const DominatorTree *DT) {
1253  return ::SimplifySRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1254 }
1255 
1256 /// SimplifyURemInst - Given operands for a URem, see if we can
1257 /// fold the result. If not, this returns null.
1258 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q,
1259  unsigned MaxRecurse) {
1260  if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
1261  return V;
1262 
1263  return 0;
1264 }
1265 
1267  const TargetLibraryInfo *TLI,
1268  const DominatorTree *DT) {
1269  return ::SimplifyURemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1270 }
1271 
1272 static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const Query &,
1273  unsigned) {
1274  // undef % X -> undef (the undef could be a snan).
1275  if (match(Op0, m_Undef()))
1276  return Op0;
1277 
1278  // X % undef -> undef
1279  if (match(Op1, m_Undef()))
1280  return Op1;
1281 
1282  return 0;
1283 }
1284 
1286  const TargetLibraryInfo *TLI,
1287  const DominatorTree *DT) {
1288  return ::SimplifyFRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1289 }
1290 
1291 /// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
1292 /// fold the result. If not, this returns null.
1293 static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
1294  const Query &Q, unsigned MaxRecurse) {
1295  if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1296  if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1297  Constant *Ops[] = { C0, C1 };
1298  return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1299  }
1300  }
1301 
1302  // 0 shift by X -> 0
1303  if (match(Op0, m_Zero()))
1304  return Op0;
1305 
1306  // X shift by 0 -> X
1307  if (match(Op1, m_Zero()))
1308  return Op0;
1309 
1310  // X shift by undef -> undef because it may shift by the bitwidth.
1311  if (match(Op1, m_Undef()))
1312  return Op1;
1313 
1314  // Shifting by the bitwidth or more is undefined.
1315  if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1))
1316  if (CI->getValue().getLimitedValue() >=
1317  Op0->getType()->getScalarSizeInBits())
1318  return UndefValue::get(Op0->getType());
1319 
1320  // If the operation is with the result of a select instruction, check whether
1321  // operating on either branch of the select always yields the same value.
1322  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1323  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1324  return V;
1325 
1326  // If the operation is with the result of a phi instruction, check whether
1327  // operating on all incoming values of the phi always yields the same value.
1328  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1329  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1330  return V;
1331 
1332  return 0;
1333 }
1334 
1335 /// SimplifyShlInst - Given operands for an Shl, see if we can
1336 /// fold the result. If not, this returns null.
1337 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1338  const Query &Q, unsigned MaxRecurse) {
1339  if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1340  return V;
1341 
1342  // undef << X -> 0
1343  if (match(Op0, m_Undef()))
1344  return Constant::getNullValue(Op0->getType());
1345 
1346  // (X >> A) << A -> X
1347  Value *X;
1348  if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1349  return X;
1350  return 0;
1351 }
1352 
1353 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1354  const DataLayout *TD, const TargetLibraryInfo *TLI,
1355  const DominatorTree *DT) {
1356  return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
1357  RecursionLimit);
1358 }
1359 
1360 /// SimplifyLShrInst - Given operands for an LShr, see if we can
1361 /// fold the result. If not, this returns null.
1362 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1363  const Query &Q, unsigned MaxRecurse) {
1364  if (Value *V = SimplifyShift(Instruction::LShr, Op0, Op1, Q, MaxRecurse))
1365  return V;
1366 
1367  // X >> X -> 0
1368  if (Op0 == Op1)
1369  return Constant::getNullValue(Op0->getType());
1370 
1371  // undef >>l X -> 0
1372  if (match(Op0, m_Undef()))
1373  return Constant::getNullValue(Op0->getType());
1374 
1375  // (X << A) >> A -> X
1376  Value *X;
1377  if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1378  cast<OverflowingBinaryOperator>(Op0)->hasNoUnsignedWrap())
1379  return X;
1380 
1381  return 0;
1382 }
1383 
1384 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1385  const DataLayout *TD,
1386  const TargetLibraryInfo *TLI,
1387  const DominatorTree *DT) {
1388  return ::SimplifyLShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
1389  RecursionLimit);
1390 }
1391 
1392 /// SimplifyAShrInst - Given operands for an AShr, see if we can
1393 /// fold the result. If not, this returns null.
1394 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1395  const Query &Q, unsigned MaxRecurse) {
1396  if (Value *V = SimplifyShift(Instruction::AShr, Op0, Op1, Q, MaxRecurse))
1397  return V;
1398 
1399  // X >> X -> 0
1400  if (Op0 == Op1)
1401  return Constant::getNullValue(Op0->getType());
1402 
1403  // all ones >>a X -> all ones
1404  if (match(Op0, m_AllOnes()))
1405  return Op0;
1406 
1407  // undef >>a X -> all ones
1408  if (match(Op0, m_Undef()))
1409  return Constant::getAllOnesValue(Op0->getType());
1410 
1411  // (X << A) >> A -> X
1412  Value *X;
1413  if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1414  cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
1415  return X;
1416 
1417  return 0;
1418 }
1419 
1420 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1421  const DataLayout *TD,
1422  const TargetLibraryInfo *TLI,
1423  const DominatorTree *DT) {
1424  return ::SimplifyAShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
1425  RecursionLimit);
1426 }
1427 
1428 /// SimplifyAndInst - Given operands for an And, see if we can
1429 /// fold the result. If not, this returns null.
1430 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
1431  unsigned MaxRecurse) {
1432  if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1433  if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1434  Constant *Ops[] = { CLHS, CRHS };
1435  return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
1436  Ops, Q.TD, Q.TLI);
1437  }
1438 
1439  // Canonicalize the constant to the RHS.
1440  std::swap(Op0, Op1);
1441  }
1442 
1443  // X & undef -> 0
1444  if (match(Op1, m_Undef()))
1445  return Constant::getNullValue(Op0->getType());
1446 
1447  // X & X = X
1448  if (Op0 == Op1)
1449  return Op0;
1450 
1451  // X & 0 = 0
1452  if (match(Op1, m_Zero()))
1453  return Op1;
1454 
1455  // X & -1 = X
1456  if (match(Op1, m_AllOnes()))
1457  return Op0;
1458 
1459  // A & ~A = ~A & A = 0
1460  if (match(Op0, m_Not(m_Specific(Op1))) ||
1461  match(Op1, m_Not(m_Specific(Op0))))
1462  return Constant::getNullValue(Op0->getType());
1463 
1464  // (A | ?) & A = A
1465  Value *A = 0, *B = 0;
1466  if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1467  (A == Op1 || B == Op1))
1468  return Op1;
1469 
1470  // A & (A | ?) = A
1471  if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1472  (A == Op0 || B == Op0))
1473  return Op0;
1474 
1475  // A & (-A) = A if A is a power of two or zero.
1476  if (match(Op0, m_Neg(m_Specific(Op1))) ||
1477  match(Op1, m_Neg(m_Specific(Op0)))) {
1478  if (isKnownToBeAPowerOfTwo(Op0, /*OrZero*/true))
1479  return Op0;
1480  if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/true))
1481  return Op1;
1482  }
1483 
1484  // Try some generic simplifications for associative operations.
1485  if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1486  MaxRecurse))
1487  return V;
1488 
1489  // And distributes over Or. Try some generic simplifications based on this.
1490  if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1491  Q, MaxRecurse))
1492  return V;
1493 
1494  // And distributes over Xor. Try some generic simplifications based on this.
1495  if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1496  Q, MaxRecurse))
1497  return V;
1498 
1499  // Or distributes over And. Try some generic simplifications based on this.
1501  Q, MaxRecurse))
1502  return V;
1503 
1504  // If the operation is with the result of a select instruction, check whether
1505  // operating on either branch of the select always yields the same value.
1506  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1507  if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1508  MaxRecurse))
1509  return V;
1510 
1511  // If the operation is with the result of a phi instruction, check whether
1512  // operating on all incoming values of the phi always yields the same value.
1513  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1514  if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1515  MaxRecurse))
1516  return V;
1517 
1518  return 0;
1519 }
1520 
1522  const TargetLibraryInfo *TLI,
1523  const DominatorTree *DT) {
1524  return ::SimplifyAndInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1525 }
1526 
1527 /// SimplifyOrInst - Given operands for an Or, see if we can
1528 /// fold the result. If not, this returns null.
1529 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
1530  unsigned MaxRecurse) {
1531  if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1532  if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1533  Constant *Ops[] = { CLHS, CRHS };
1534  return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
1535  Ops, Q.TD, Q.TLI);
1536  }
1537 
1538  // Canonicalize the constant to the RHS.
1539  std::swap(Op0, Op1);
1540  }
1541 
1542  // X | undef -> -1
1543  if (match(Op1, m_Undef()))
1544  return Constant::getAllOnesValue(Op0->getType());
1545 
1546  // X | X = X
1547  if (Op0 == Op1)
1548  return Op0;
1549 
1550  // X | 0 = X
1551  if (match(Op1, m_Zero()))
1552  return Op0;
1553 
1554  // X | -1 = -1
1555  if (match(Op1, m_AllOnes()))
1556  return Op1;
1557 
1558  // A | ~A = ~A | A = -1
1559  if (match(Op0, m_Not(m_Specific(Op1))) ||
1560  match(Op1, m_Not(m_Specific(Op0))))
1561  return Constant::getAllOnesValue(Op0->getType());
1562 
1563  // (A & ?) | A = A
1564  Value *A = 0, *B = 0;
1565  if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1566  (A == Op1 || B == Op1))
1567  return Op1;
1568 
1569  // A | (A & ?) = A
1570  if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1571  (A == Op0 || B == Op0))
1572  return Op0;
1573 
1574  // ~(A & ?) | A = -1
1575  if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1576  (A == Op1 || B == Op1))
1577  return Constant::getAllOnesValue(Op1->getType());
1578 
1579  // A | ~(A & ?) = -1
1580  if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1581  (A == Op0 || B == Op0))
1582  return Constant::getAllOnesValue(Op0->getType());
1583 
1584  // Try some generic simplifications for associative operations.
1585  if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1586  MaxRecurse))
1587  return V;
1588 
1589  // Or distributes over And. Try some generic simplifications based on this.
1590  if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1591  MaxRecurse))
1592  return V;
1593 
1594  // And distributes over Or. Try some generic simplifications based on this.
1596  Q, MaxRecurse))
1597  return V;
1598 
1599  // If the operation is with the result of a select instruction, check whether
1600  // operating on either branch of the select always yields the same value.
1601  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1602  if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1603  MaxRecurse))
1604  return V;
1605 
1606  // If the operation is with the result of a phi instruction, check whether
1607  // operating on all incoming values of the phi always yields the same value.
1608  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1609  if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1610  return V;
1611 
1612  return 0;
1613 }
1614 
1616  const TargetLibraryInfo *TLI,
1617  const DominatorTree *DT) {
1618  return ::SimplifyOrInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1619 }
1620 
1621 /// SimplifyXorInst - Given operands for a Xor, see if we can
1622 /// fold the result. If not, this returns null.
1623 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q,
1624  unsigned MaxRecurse) {
1625  if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1626  if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1627  Constant *Ops[] = { CLHS, CRHS };
1628  return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
1629  Ops, Q.TD, Q.TLI);
1630  }
1631 
1632  // Canonicalize the constant to the RHS.
1633  std::swap(Op0, Op1);
1634  }
1635 
1636  // A ^ undef -> undef
1637  if (match(Op1, m_Undef()))
1638  return Op1;
1639 
1640  // A ^ 0 = A
1641  if (match(Op1, m_Zero()))
1642  return Op0;
1643 
1644  // A ^ A = 0
1645  if (Op0 == Op1)
1646  return Constant::getNullValue(Op0->getType());
1647 
1648  // A ^ ~A = ~A ^ A = -1
1649  if (match(Op0, m_Not(m_Specific(Op1))) ||
1650  match(Op1, m_Not(m_Specific(Op0))))
1651  return Constant::getAllOnesValue(Op0->getType());
1652 
1653  // Try some generic simplifications for associative operations.
1654  if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1655  MaxRecurse))
1656  return V;
1657 
1658  // And distributes over Xor. Try some generic simplifications based on this.
1660  Q, MaxRecurse))
1661  return V;
1662 
1663  // Threading Xor over selects and phi nodes is pointless, so don't bother.
1664  // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1665  // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1666  // only if B and C are equal. If B and C are equal then (since we assume
1667  // that operands have already been simplified) "select(cond, B, C)" should
1668  // have been simplified to the common value of B and C already. Analysing
1669  // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1670  // for threading over phi nodes.
1671 
1672  return 0;
1673 }
1674 
1676  const TargetLibraryInfo *TLI,
1677  const DominatorTree *DT) {
1678  return ::SimplifyXorInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1679 }
1680 
1681 static Type *GetCompareTy(Value *Op) {
1682  return CmpInst::makeCmpResultType(Op->getType());
1683 }
1684 
1685 /// ExtractEquivalentCondition - Rummage around inside V looking for something
1686 /// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
1687 /// otherwise return null. Helper function for analyzing max/min idioms.
1689  Value *LHS, Value *RHS) {
1690  SelectInst *SI = dyn_cast<SelectInst>(V);
1691  if (!SI)
1692  return 0;
1693  CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1694  if (!Cmp)
1695  return 0;
1696  Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1697  if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1698  return Cmp;
1699  if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1700  LHS == CmpRHS && RHS == CmpLHS)
1701  return Cmp;
1702  return 0;
1703 }
1704 
1705 // A significant optimization not implemented here is assuming that alloca
1706 // addresses are not equal to incoming argument values. They don't *alias*,
1707 // as we say, but that doesn't mean they aren't equal, so we take a
1708 // conservative approach.
1709 //
1710 // This is inspired in part by C++11 5.10p1:
1711 // "Two pointers of the same type compare equal if and only if they are both
1712 // null, both point to the same function, or both represent the same
1713 // address."
1714 //
1715 // This is pretty permissive.
1716 //
1717 // It's also partly due to C11 6.5.9p6:
1718 // "Two pointers compare equal if and only if both are null pointers, both are
1719 // pointers to the same object (including a pointer to an object and a
1720 // subobject at its beginning) or function, both are pointers to one past the
1721 // last element of the same array object, or one is a pointer to one past the
1722 // end of one array object and the other is a pointer to the start of a
1723 // different array object that happens to immediately follow the first array
1724 // object in the address space.)
1725 //
1726 // C11's version is more restrictive, however there's no reason why an argument
1727 // couldn't be a one-past-the-end value for a stack object in the caller and be
1728 // equal to the beginning of a stack object in the callee.
1729 //
1730 // If the C and C++ standards are ever made sufficiently restrictive in this
1731 // area, it may be possible to update LLVM's semantics accordingly and reinstate
1732 // this optimization.
1734  const TargetLibraryInfo *TLI,
1735  CmpInst::Predicate Pred,
1736  Value *LHS, Value *RHS) {
1737  // First, skip past any trivial no-ops.
1738  LHS = LHS->stripPointerCasts();
1739  RHS = RHS->stripPointerCasts();
1740 
1741  // A non-null pointer is not equal to a null pointer.
1742  if (llvm::isKnownNonNull(LHS, TLI) && isa<ConstantPointerNull>(RHS) &&
1743  (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
1744  return ConstantInt::get(GetCompareTy(LHS),
1745  !CmpInst::isTrueWhenEqual(Pred));
1746 
1747  // We can only fold certain predicates on pointer comparisons.
1748  switch (Pred) {
1749  default:
1750  return 0;
1751 
1752  // Equality comaprisons are easy to fold.
1753  case CmpInst::ICMP_EQ:
1754  case CmpInst::ICMP_NE:
1755  break;
1756 
1757  // We can only handle unsigned relational comparisons because 'inbounds' on
1758  // a GEP only protects against unsigned wrapping.
1759  case CmpInst::ICMP_UGT:
1760  case CmpInst::ICMP_UGE:
1761  case CmpInst::ICMP_ULT:
1762  case CmpInst::ICMP_ULE:
1763  // However, we have to switch them to their signed variants to handle
1764  // negative indices from the base pointer.
1765  Pred = ICmpInst::getSignedPredicate(Pred);
1766  break;
1767  }
1768 
1769  // Strip off any constant offsets so that we can reason about them.
1770  // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
1771  // here and compare base addresses like AliasAnalysis does, however there are
1772  // numerous hazards. AliasAnalysis and its utilities rely on special rules
1773  // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
1774  // doesn't need to guarantee pointer inequality when it says NoAlias.
1775  Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS);
1776  Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS);
1777 
1778  // If LHS and RHS are related via constant offsets to the same base
1779  // value, we can replace it with an icmp which just compares the offsets.
1780  if (LHS == RHS)
1781  return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
1782 
1783  // Various optimizations for (in)equality comparisons.
1784  if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
1785  // Different non-empty allocations that exist at the same time have
1786  // different addresses (if the program can tell). Global variables always
1787  // exist, so they always exist during the lifetime of each other and all
1788  // allocas. Two different allocas usually have different addresses...
1789  //
1790  // However, if there's an @llvm.stackrestore dynamically in between two
1791  // allocas, they may have the same address. It's tempting to reduce the
1792  // scope of the problem by only looking at *static* allocas here. That would
1793  // cover the majority of allocas while significantly reducing the likelihood
1794  // of having an @llvm.stackrestore pop up in the middle. However, it's not
1795  // actually impossible for an @llvm.stackrestore to pop up in the middle of
1796  // an entry block. Also, if we have a block that's not attached to a
1797  // function, we can't tell if it's "static" under the current definition.
1798  // Theoretically, this problem could be fixed by creating a new kind of
1799  // instruction kind specifically for static allocas. Such a new instruction
1800  // could be required to be at the top of the entry block, thus preventing it
1801  // from being subject to a @llvm.stackrestore. Instcombine could even
1802  // convert regular allocas into these special allocas. It'd be nifty.
1803  // However, until then, this problem remains open.
1804  //
1805  // So, we'll assume that two non-empty allocas have different addresses
1806  // for now.
1807  //
1808  // With all that, if the offsets are within the bounds of their allocations
1809  // (and not one-past-the-end! so we can't use inbounds!), and their
1810  // allocations aren't the same, the pointers are not equal.
1811  //
1812  // Note that it's not necessary to check for LHS being a global variable
1813  // address, due to canonicalization and constant folding.
1814  if (isa<AllocaInst>(LHS) &&
1815  (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
1816  ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
1817  ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
1818  uint64_t LHSSize, RHSSize;
1819  if (LHSOffsetCI && RHSOffsetCI &&
1820  getObjectSize(LHS, LHSSize, TD, TLI) &&
1821  getObjectSize(RHS, RHSSize, TD, TLI)) {
1822  const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
1823  const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
1824  if (!LHSOffsetValue.isNegative() &&
1825  !RHSOffsetValue.isNegative() &&
1826  LHSOffsetValue.ult(LHSSize) &&
1827  RHSOffsetValue.ult(RHSSize)) {
1828  return ConstantInt::get(GetCompareTy(LHS),
1829  !CmpInst::isTrueWhenEqual(Pred));
1830  }
1831  }
1832 
1833  // Repeat the above check but this time without depending on DataLayout
1834  // or being able to compute a precise size.
1835  if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
1836  !cast<PointerType>(RHS->getType())->isEmptyTy() &&
1837  LHSOffset->isNullValue() &&
1838  RHSOffset->isNullValue())
1839  return ConstantInt::get(GetCompareTy(LHS),
1840  !CmpInst::isTrueWhenEqual(Pred));
1841  }
1842 
1843  // Even if an non-inbounds GEP occurs along the path we can still optimize
1844  // equality comparisons concerning the result. We avoid walking the whole
1845  // chain again by starting where the last calls to
1846  // stripAndComputeConstantOffsets left off and accumulate the offsets.
1847  Constant *LHSNoBound = stripAndComputeConstantOffsets(TD, LHS, true);
1848  Constant *RHSNoBound = stripAndComputeConstantOffsets(TD, RHS, true);
1849  if (LHS == RHS)
1850  return ConstantExpr::getICmp(Pred,
1851  ConstantExpr::getAdd(LHSOffset, LHSNoBound),
1852  ConstantExpr::getAdd(RHSOffset, RHSNoBound));
1853  }
1854 
1855  // Otherwise, fail.
1856  return 0;
1857 }
1858 
1859 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
1860 /// fold the result. If not, this returns null.
1861 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
1862  const Query &Q, unsigned MaxRecurse) {
1863  CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
1864  assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
1865 
1866  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
1867  if (Constant *CRHS = dyn_cast<Constant>(RHS))
1868  return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
1869 
1870  // If we have a constant, make sure it is on the RHS.
1871  std::swap(LHS, RHS);
1872  Pred = CmpInst::getSwappedPredicate(Pred);
1873  }
1874 
1875  Type *ITy = GetCompareTy(LHS); // The return type.
1876  Type *OpTy = LHS->getType(); // The operand type.
1877 
1878  // icmp X, X -> true/false
1879  // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
1880  // because X could be 0.
1881  if (LHS == RHS || isa<UndefValue>(RHS))
1882  return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
1883 
1884  // Special case logic when the operands have i1 type.
1885  if (OpTy->getScalarType()->isIntegerTy(1)) {
1886  switch (Pred) {
1887  default: break;
1888  case ICmpInst::ICMP_EQ:
1889  // X == 1 -> X
1890  if (match(RHS, m_One()))
1891  return LHS;
1892  break;
1893  case ICmpInst::ICMP_NE:
1894  // X != 0 -> X
1895  if (match(RHS, m_Zero()))
1896  return LHS;
1897  break;
1898  case ICmpInst::ICMP_UGT:
1899  // X >u 0 -> X
1900  if (match(RHS, m_Zero()))
1901  return LHS;
1902  break;
1903  case ICmpInst::ICMP_UGE:
1904  // X >=u 1 -> X
1905  if (match(RHS, m_One()))
1906  return LHS;
1907  break;
1908  case ICmpInst::ICMP_SLT:
1909  // X <s 0 -> X
1910  if (match(RHS, m_Zero()))
1911  return LHS;
1912  break;
1913  case ICmpInst::ICMP_SLE:
1914  // X <=s -1 -> X
1915  if (match(RHS, m_One()))
1916  return LHS;
1917  break;
1918  }
1919  }
1920 
1921  // If we are comparing with zero then try hard since this is a common case.
1922  if (match(RHS, m_Zero())) {
1923  bool LHSKnownNonNegative, LHSKnownNegative;
1924  switch (Pred) {
1925  default: llvm_unreachable("Unknown ICmp predicate!");
1926  case ICmpInst::ICMP_ULT:
1927  return getFalse(ITy);
1928  case ICmpInst::ICMP_UGE:
1929  return getTrue(ITy);
1930  case ICmpInst::ICMP_EQ:
1931  case ICmpInst::ICMP_ULE:
1932  if (isKnownNonZero(LHS, Q.TD))
1933  return getFalse(ITy);
1934  break;
1935  case ICmpInst::ICMP_NE:
1936  case ICmpInst::ICMP_UGT:
1937  if (isKnownNonZero(LHS, Q.TD))
1938  return getTrue(ITy);
1939  break;
1940  case ICmpInst::ICMP_SLT:
1941  ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1942  if (LHSKnownNegative)
1943  return getTrue(ITy);
1944  if (LHSKnownNonNegative)
1945  return getFalse(ITy);
1946  break;
1947  case ICmpInst::ICMP_SLE:
1948  ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1949  if (LHSKnownNegative)
1950  return getTrue(ITy);
1951  if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
1952  return getFalse(ITy);
1953  break;
1954  case ICmpInst::ICMP_SGE:
1955  ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1956  if (LHSKnownNegative)
1957  return getFalse(ITy);
1958  if (LHSKnownNonNegative)
1959  return getTrue(ITy);
1960  break;
1961  case ICmpInst::ICMP_SGT:
1962  ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1963  if (LHSKnownNegative)
1964  return getFalse(ITy);
1965  if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
1966  return getTrue(ITy);
1967  break;
1968  }
1969  }
1970 
1971  // See if we are doing a comparison with a constant integer.
1972  if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
1973  // Rule out tautological comparisons (eg., ult 0 or uge 0).
1974  ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
1975  if (RHS_CR.isEmptySet())
1976  return ConstantInt::getFalse(CI->getContext());
1977  if (RHS_CR.isFullSet())
1978  return ConstantInt::getTrue(CI->getContext());
1979 
1980  // Many binary operators with constant RHS have easy to compute constant
1981  // range. Use them to check whether the comparison is a tautology.
1982  uint32_t Width = CI->getBitWidth();
1983  APInt Lower = APInt(Width, 0);
1984  APInt Upper = APInt(Width, 0);
1985  ConstantInt *CI2;
1986  if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
1987  // 'urem x, CI2' produces [0, CI2).
1988  Upper = CI2->getValue();
1989  } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
1990  // 'srem x, CI2' produces (-|CI2|, |CI2|).
1991  Upper = CI2->getValue().abs();
1992  Lower = (-Upper) + 1;
1993  } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
1994  // 'udiv CI2, x' produces [0, CI2].
1995  Upper = CI2->getValue() + 1;
1996  } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
1997  // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
1998  APInt NegOne = APInt::getAllOnesValue(Width);
1999  if (!CI2->isZero())
2000  Upper = NegOne.udiv(CI2->getValue()) + 1;
2001  } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
2002  // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2].
2003  APInt IntMin = APInt::getSignedMinValue(Width);
2004  APInt IntMax = APInt::getSignedMaxValue(Width);
2005  APInt Val = CI2->getValue().abs();
2006  if (!Val.isMinValue()) {
2007  Lower = IntMin.sdiv(Val);
2008  Upper = IntMax.sdiv(Val) + 1;
2009  }
2010  } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
2011  // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
2012  APInt NegOne = APInt::getAllOnesValue(Width);
2013  if (CI2->getValue().ult(Width))
2014  Upper = NegOne.lshr(CI2->getValue()) + 1;
2015  } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
2016  // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
2017  APInt IntMin = APInt::getSignedMinValue(Width);
2018  APInt IntMax = APInt::getSignedMaxValue(Width);
2019  if (CI2->getValue().ult(Width)) {
2020  Lower = IntMin.ashr(CI2->getValue());
2021  Upper = IntMax.ashr(CI2->getValue()) + 1;
2022  }
2023  } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
2024  // 'or x, CI2' produces [CI2, UINT_MAX].
2025  Lower = CI2->getValue();
2026  } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
2027  // 'and x, CI2' produces [0, CI2].
2028  Upper = CI2->getValue() + 1;
2029  }
2030  if (Lower != Upper) {
2031  ConstantRange LHS_CR = ConstantRange(Lower, Upper);
2032  if (RHS_CR.contains(LHS_CR))
2033  return ConstantInt::getTrue(RHS->getContext());
2034  if (RHS_CR.inverse().contains(LHS_CR))
2035  return ConstantInt::getFalse(RHS->getContext());
2036  }
2037  }
2038 
2039  // Compare of cast, for example (zext X) != 0 -> X != 0
2040  if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
2041  Instruction *LI = cast<CastInst>(LHS);
2042  Value *SrcOp = LI->getOperand(0);
2043  Type *SrcTy = SrcOp->getType();
2044  Type *DstTy = LI->getType();
2045 
2046  // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
2047  // if the integer type is the same size as the pointer type.
2048  if (MaxRecurse && Q.TD && isa<PtrToIntInst>(LI) &&
2049  Q.TD->getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
2050  if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2051  // Transfer the cast to the constant.
2052  if (Value *V = SimplifyICmpInst(Pred, SrcOp,
2053  ConstantExpr::getIntToPtr(RHSC, SrcTy),
2054  Q, MaxRecurse-1))
2055  return V;
2056  } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
2057  if (RI->getOperand(0)->getType() == SrcTy)
2058  // Compare without the cast.
2059  if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2060  Q, MaxRecurse-1))
2061  return V;
2062  }
2063  }
2064 
2065  if (isa<ZExtInst>(LHS)) {
2066  // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
2067  // same type.
2068  if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
2069  if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2070  // Compare X and Y. Note that signed predicates become unsigned.
2072  SrcOp, RI->getOperand(0), Q,
2073  MaxRecurse-1))
2074  return V;
2075  }
2076  // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
2077  // too. If not, then try to deduce the result of the comparison.
2078  else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2079  // Compute the constant that would happen if we truncated to SrcTy then
2080  // reextended to DstTy.
2081  Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2082  Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
2083 
2084  // If the re-extended constant didn't change then this is effectively
2085  // also a case of comparing two zero-extended values.
2086  if (RExt == CI && MaxRecurse)
2088  SrcOp, Trunc, Q, MaxRecurse-1))
2089  return V;
2090 
2091  // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
2092  // there. Use this to work out the result of the comparison.
2093  if (RExt != CI) {
2094  switch (Pred) {
2095  default: llvm_unreachable("Unknown ICmp predicate!");
2096  // LHS <u RHS.
2097  case ICmpInst::ICMP_EQ:
2098  case ICmpInst::ICMP_UGT:
2099  case ICmpInst::ICMP_UGE:
2100  return ConstantInt::getFalse(CI->getContext());
2101 
2102  case ICmpInst::ICMP_NE:
2103  case ICmpInst::ICMP_ULT:
2104  case ICmpInst::ICMP_ULE:
2105  return ConstantInt::getTrue(CI->getContext());
2106 
2107  // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
2108  // is non-negative then LHS <s RHS.
2109  case ICmpInst::ICMP_SGT:
2110  case ICmpInst::ICMP_SGE:
2111  return CI->getValue().isNegative() ?
2112  ConstantInt::getTrue(CI->getContext()) :
2113  ConstantInt::getFalse(CI->getContext());
2114 
2115  case ICmpInst::ICMP_SLT:
2116  case ICmpInst::ICMP_SLE:
2117  return CI->getValue().isNegative() ?
2118  ConstantInt::getFalse(CI->getContext()) :
2119  ConstantInt::getTrue(CI->getContext());
2120  }
2121  }
2122  }
2123  }
2124 
2125  if (isa<SExtInst>(LHS)) {
2126  // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
2127  // same type.
2128  if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
2129  if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2130  // Compare X and Y. Note that the predicate does not change.
2131  if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2132  Q, MaxRecurse-1))
2133  return V;
2134  }
2135  // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
2136  // too. If not, then try to deduce the result of the comparison.
2137  else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2138  // Compute the constant that would happen if we truncated to SrcTy then
2139  // reextended to DstTy.
2140  Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2141  Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
2142 
2143  // If the re-extended constant didn't change then this is effectively
2144  // also a case of comparing two sign-extended values.
2145  if (RExt == CI && MaxRecurse)
2146  if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
2147  return V;
2148 
2149  // Otherwise the upper bits of LHS are all equal, while RHS has varying
2150  // bits there. Use this to work out the result of the comparison.
2151  if (RExt != CI) {
2152  switch (Pred) {
2153  default: llvm_unreachable("Unknown ICmp predicate!");
2154  case ICmpInst::ICMP_EQ:
2155  return ConstantInt::getFalse(CI->getContext());
2156  case ICmpInst::ICMP_NE:
2157  return ConstantInt::getTrue(CI->getContext());
2158 
2159  // If RHS is non-negative then LHS <s RHS. If RHS is negative then
2160  // LHS >s RHS.
2161  case ICmpInst::ICMP_SGT:
2162  case ICmpInst::ICMP_SGE:
2163  return CI->getValue().isNegative() ?
2164  ConstantInt::getTrue(CI->getContext()) :
2165  ConstantInt::getFalse(CI->getContext());
2166  case ICmpInst::ICMP_SLT:
2167  case ICmpInst::ICMP_SLE:
2168  return CI->getValue().isNegative() ?
2169  ConstantInt::getFalse(CI->getContext()) :
2170  ConstantInt::getTrue(CI->getContext());
2171 
2172  // If LHS is non-negative then LHS <u RHS. If LHS is negative then
2173  // LHS >u RHS.
2174  case ICmpInst::ICMP_UGT:
2175  case ICmpInst::ICMP_UGE:
2176  // Comparison is true iff the LHS <s 0.
2177  if (MaxRecurse)
2178  if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
2179  Constant::getNullValue(SrcTy),
2180  Q, MaxRecurse-1))
2181  return V;
2182  break;
2183  case ICmpInst::ICMP_ULT:
2184  case ICmpInst::ICMP_ULE:
2185  // Comparison is true iff the LHS >=s 0.
2186  if (MaxRecurse)
2187  if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
2188  Constant::getNullValue(SrcTy),
2189  Q, MaxRecurse-1))
2190  return V;
2191  break;
2192  }
2193  }
2194  }
2195  }
2196  }
2197 
2198  // Special logic for binary operators.
2199  BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2200  BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2201  if (MaxRecurse && (LBO || RBO)) {
2202  // Analyze the case when either LHS or RHS is an add instruction.
2203  Value *A = 0, *B = 0, *C = 0, *D = 0;
2204  // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2205  bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2206  if (LBO && LBO->getOpcode() == Instruction::Add) {
2207  A = LBO->getOperand(0); B = LBO->getOperand(1);
2208  NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
2209  (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2210  (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2211  }
2212  if (RBO && RBO->getOpcode() == Instruction::Add) {
2213  C = RBO->getOperand(0); D = RBO->getOperand(1);
2214  NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
2215  (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2216  (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2217  }
2218 
2219  // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2220  if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2221  if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2223  Q, MaxRecurse-1))
2224  return V;
2225 
2226  // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2227  if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2228  if (Value *V = SimplifyICmpInst(Pred,
2230  C == LHS ? D : C, Q, MaxRecurse-1))
2231  return V;
2232 
2233  // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2234  if (A && C && (A == C || A == D || B == C || B == D) &&
2235  NoLHSWrapProblem && NoRHSWrapProblem) {
2236  // Determine Y and Z in the form icmp (X+Y), (X+Z).
2237  Value *Y, *Z;
2238  if (A == C) {
2239  // C + B == C + D -> B == D
2240  Y = B;
2241  Z = D;
2242  } else if (A == D) {
2243  // D + B == C + D -> B == C
2244  Y = B;
2245  Z = C;
2246  } else if (B == C) {
2247  // A + C == C + D -> A == D
2248  Y = A;
2249  Z = D;
2250  } else {
2251  assert(B == D);
2252  // A + D == C + D -> A == C
2253  Y = A;
2254  Z = C;
2255  }
2256  if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
2257  return V;
2258  }
2259  }
2260 
2261  // icmp pred (urem X, Y), Y
2262  if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2263  bool KnownNonNegative, KnownNegative;
2264  switch (Pred) {
2265  default:
2266  break;
2267  case ICmpInst::ICMP_SGT:
2268  case ICmpInst::ICMP_SGE:
2269  ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
2270  if (!KnownNonNegative)
2271  break;
2272  // fall-through
2273  case ICmpInst::ICMP_EQ:
2274  case ICmpInst::ICMP_UGT:
2275  case ICmpInst::ICMP_UGE:
2276  return getFalse(ITy);
2277  case ICmpInst::ICMP_SLT:
2278  case ICmpInst::ICMP_SLE:
2279  ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
2280  if (!KnownNonNegative)
2281  break;
2282  // fall-through
2283  case ICmpInst::ICMP_NE:
2284  case ICmpInst::ICMP_ULT:
2285  case ICmpInst::ICMP_ULE:
2286  return getTrue(ITy);
2287  }
2288  }
2289 
2290  // icmp pred X, (urem Y, X)
2291  if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2292  bool KnownNonNegative, KnownNegative;
2293  switch (Pred) {
2294  default:
2295  break;
2296  case ICmpInst::ICMP_SGT:
2297  case ICmpInst::ICMP_SGE:
2298  ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
2299  if (!KnownNonNegative)
2300  break;
2301  // fall-through
2302  case ICmpInst::ICMP_NE:
2303  case ICmpInst::ICMP_UGT:
2304  case ICmpInst::ICMP_UGE:
2305  return getTrue(ITy);
2306  case ICmpInst::ICMP_SLT:
2307  case ICmpInst::ICMP_SLE:
2308  ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
2309  if (!KnownNonNegative)
2310  break;
2311  // fall-through
2312  case ICmpInst::ICMP_EQ:
2313  case ICmpInst::ICMP_ULT:
2314  case ICmpInst::ICMP_ULE:
2315  return getFalse(ITy);
2316  }
2317  }
2318 
2319  // x udiv y <=u x.
2320  if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
2321  // icmp pred (X /u Y), X
2322  if (Pred == ICmpInst::ICMP_UGT)
2323  return getFalse(ITy);
2324  if (Pred == ICmpInst::ICMP_ULE)
2325  return getTrue(ITy);
2326  }
2327 
2328  if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2329  LBO->getOperand(1) == RBO->getOperand(1)) {
2330  switch (LBO->getOpcode()) {
2331  default: break;
2332  case Instruction::UDiv:
2333  case Instruction::LShr:
2334  if (ICmpInst::isSigned(Pred))
2335  break;
2336  // fall-through
2337  case Instruction::SDiv:
2338  case Instruction::AShr:
2339  if (!LBO->isExact() || !RBO->isExact())
2340  break;
2341  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2342  RBO->getOperand(0), Q, MaxRecurse-1))
2343  return V;
2344  break;
2345  case Instruction::Shl: {
2346  bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2347  bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2348  if (!NUW && !NSW)
2349  break;
2350  if (!NSW && ICmpInst::isSigned(Pred))
2351  break;
2352  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2353  RBO->getOperand(0), Q, MaxRecurse-1))
2354  return V;
2355  break;
2356  }
2357  }
2358  }
2359 
2360  // Simplify comparisons involving max/min.
2361  Value *A, *B;
2363  CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2364 
2365  // Signed variants on "max(a,b)>=a -> true".
2366  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2367  if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
2368  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2369  // We analyze this as smax(A, B) pred A.
2370  P = Pred;
2371  } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2372  (A == LHS || B == LHS)) {
2373  if (A != LHS) std::swap(A, B); // A pred smax(A, B).
2374  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2375  // We analyze this as smax(A, B) swapped-pred A.
2376  P = CmpInst::getSwappedPredicate(Pred);
2377  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2378  (A == RHS || B == RHS)) {
2379  if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
2380  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2381  // We analyze this as smax(-A, -B) swapped-pred -A.
2382  // Note that we do not need to actually form -A or -B thanks to EqP.
2383  P = CmpInst::getSwappedPredicate(Pred);
2384  } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2385  (A == LHS || B == LHS)) {
2386  if (A != LHS) std::swap(A, B); // A pred smin(A, B).
2387  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2388  // We analyze this as smax(-A, -B) pred -A.
2389  // Note that we do not need to actually form -A or -B thanks to EqP.
2390  P = Pred;
2391  }
2392  if (P != CmpInst::BAD_ICMP_PREDICATE) {
2393  // Cases correspond to "max(A, B) p A".
2394  switch (P) {
2395  default:
2396  break;
2397  case CmpInst::ICMP_EQ:
2398  case CmpInst::ICMP_SLE:
2399  // Equivalent to "A EqP B". This may be the same as the condition tested
2400  // in the max/min; if so, we can just return that.
2401  if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2402  return V;
2403  if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2404  return V;
2405  // Otherwise, see if "A EqP B" simplifies.
2406  if (MaxRecurse)
2407  if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2408  return V;
2409  break;
2410  case CmpInst::ICMP_NE:
2411  case CmpInst::ICMP_SGT: {
2413  // Equivalent to "A InvEqP B". This may be the same as the condition
2414  // tested in the max/min; if so, we can just return that.
2415  if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2416  return V;
2417  if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2418  return V;
2419  // Otherwise, see if "A InvEqP B" simplifies.
2420  if (MaxRecurse)
2421  if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2422  return V;
2423  break;
2424  }
2425  case CmpInst::ICMP_SGE:
2426  // Always true.
2427  return getTrue(ITy);
2428  case CmpInst::ICMP_SLT:
2429  // Always false.
2430  return getFalse(ITy);
2431  }
2432  }
2433 
2434  // Unsigned variants on "max(a,b)>=a -> true".
2436  if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2437  if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
2438  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2439  // We analyze this as umax(A, B) pred A.
2440  P = Pred;
2441  } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2442  (A == LHS || B == LHS)) {
2443  if (A != LHS) std::swap(A, B); // A pred umax(A, B).
2444  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2445  // We analyze this as umax(A, B) swapped-pred A.
2446  P = CmpInst::getSwappedPredicate(Pred);
2447  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2448  (A == RHS || B == RHS)) {
2449  if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
2450  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2451  // We analyze this as umax(-A, -B) swapped-pred -A.
2452  // Note that we do not need to actually form -A or -B thanks to EqP.
2453  P = CmpInst::getSwappedPredicate(Pred);
2454  } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2455  (A == LHS || B == LHS)) {
2456  if (A != LHS) std::swap(A, B); // A pred umin(A, B).
2457  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2458  // We analyze this as umax(-A, -B) pred -A.
2459  // Note that we do not need to actually form -A or -B thanks to EqP.
2460  P = Pred;
2461  }
2462  if (P != CmpInst::BAD_ICMP_PREDICATE) {
2463  // Cases correspond to "max(A, B) p A".
2464  switch (P) {
2465  default:
2466  break;
2467  case CmpInst::ICMP_EQ:
2468  case CmpInst::ICMP_ULE:
2469  // Equivalent to "A EqP B". This may be the same as the condition tested
2470  // in the max/min; if so, we can just return that.
2471  if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2472  return V;
2473  if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2474  return V;
2475  // Otherwise, see if "A EqP B" simplifies.
2476  if (MaxRecurse)
2477  if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2478  return V;
2479  break;
2480  case CmpInst::ICMP_NE:
2481  case CmpInst::ICMP_UGT: {
2483  // Equivalent to "A InvEqP B". This may be the same as the condition
2484  // tested in the max/min; if so, we can just return that.
2485  if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2486  return V;
2487  if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2488  return V;
2489  // Otherwise, see if "A InvEqP B" simplifies.
2490  if (MaxRecurse)
2491  if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2492  return V;
2493  break;
2494  }
2495  case CmpInst::ICMP_UGE:
2496  // Always true.
2497  return getTrue(ITy);
2498  case CmpInst::ICMP_ULT:
2499  // Always false.
2500  return getFalse(ITy);
2501  }
2502  }
2503 
2504  // Variants on "max(x,y) >= min(x,z)".
2505  Value *C, *D;
2506  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2507  match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2508  (A == C || A == D || B == C || B == D)) {
2509  // max(x, ?) pred min(x, ?).
2510  if (Pred == CmpInst::ICMP_SGE)
2511  // Always true.
2512  return getTrue(ITy);
2513  if (Pred == CmpInst::ICMP_SLT)
2514  // Always false.
2515  return getFalse(ITy);
2516  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2517  match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2518  (A == C || A == D || B == C || B == D)) {
2519  // min(x, ?) pred max(x, ?).
2520  if (Pred == CmpInst::ICMP_SLE)
2521  // Always true.
2522  return getTrue(ITy);
2523  if (Pred == CmpInst::ICMP_SGT)
2524  // Always false.
2525  return getFalse(ITy);
2526  } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2527  match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2528  (A == C || A == D || B == C || B == D)) {
2529  // max(x, ?) pred min(x, ?).
2530  if (Pred == CmpInst::ICMP_UGE)
2531  // Always true.
2532  return getTrue(ITy);
2533  if (Pred == CmpInst::ICMP_ULT)
2534  // Always false.
2535  return getFalse(ITy);
2536  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2537  match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2538  (A == C || A == D || B == C || B == D)) {
2539  // min(x, ?) pred max(x, ?).
2540  if (Pred == CmpInst::ICMP_ULE)
2541  // Always true.
2542  return getTrue(ITy);
2543  if (Pred == CmpInst::ICMP_UGT)
2544  // Always false.
2545  return getFalse(ITy);
2546  }
2547 
2548  // Simplify comparisons of related pointers using a powerful, recursive
2549  // GEP-walk when we have target data available..
2550  if (LHS->getType()->isPointerTy())
2551  if (Constant *C = computePointerICmp(Q.TD, Q.TLI, Pred, LHS, RHS))
2552  return C;
2553 
2554  if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
2555  if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
2556  if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
2557  GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
2558  (ICmpInst::isEquality(Pred) ||
2559  (GLHS->isInBounds() && GRHS->isInBounds() &&
2560  Pred == ICmpInst::getSignedPredicate(Pred)))) {
2561  // The bases are equal and the indices are constant. Build a constant
2562  // expression GEP with the same indices and a null base pointer to see
2563  // what constant folding can make out of it.
2564  Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
2565  SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
2566  Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
2567 
2568  SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
2569  Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
2570  return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
2571  }
2572  }
2573  }
2574 
2575  // If the comparison is with the result of a select instruction, check whether
2576  // comparing with either branch of the select always yields the same value.
2577  if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2578  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2579  return V;
2580 
2581  // If the comparison is with the result of a phi instruction, check whether
2582  // doing the compare with each incoming phi value yields a common result.
2583  if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2584  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2585  return V;
2586 
2587  return 0;
2588 }
2589 
2591  const DataLayout *TD,
2592  const TargetLibraryInfo *TLI,
2593  const DominatorTree *DT) {
2594  return ::SimplifyICmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2595  RecursionLimit);
2596 }
2597 
2598 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
2599 /// fold the result. If not, this returns null.
2600 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2601  const Query &Q, unsigned MaxRecurse) {
2602  CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2603  assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
2604 
2605  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2606  if (Constant *CRHS = dyn_cast<Constant>(RHS))
2607  return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
2608 
2609  // If we have a constant, make sure it is on the RHS.
2610  std::swap(LHS, RHS);
2611  Pred = CmpInst::getSwappedPredicate(Pred);
2612  }
2613 
2614  // Fold trivial predicates.
2615  if (Pred == FCmpInst::FCMP_FALSE)
2616  return ConstantInt::get(GetCompareTy(LHS), 0);
2617  if (Pred == FCmpInst::FCMP_TRUE)
2618  return ConstantInt::get(GetCompareTy(LHS), 1);
2619 
2620  if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
2621  return UndefValue::get(GetCompareTy(LHS));
2622 
2623  // fcmp x,x -> true/false. Not all compares are foldable.
2624  if (LHS == RHS) {
2625  if (CmpInst::isTrueWhenEqual(Pred))
2626  return ConstantInt::get(GetCompareTy(LHS), 1);
2627  if (CmpInst::isFalseWhenEqual(Pred))
2628  return ConstantInt::get(GetCompareTy(LHS), 0);
2629  }
2630 
2631  // Handle fcmp with constant RHS
2632  if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2633  // If the constant is a nan, see if we can fold the comparison based on it.
2634  if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
2635  if (CFP->getValueAPF().isNaN()) {
2636  if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
2637  return ConstantInt::getFalse(CFP->getContext());
2638  assert(FCmpInst::isUnordered(Pred) &&
2639  "Comparison must be either ordered or unordered!");
2640  // True if unordered.
2641  return ConstantInt::getTrue(CFP->getContext());
2642  }
2643  // Check whether the constant is an infinity.
2644  if (CFP->getValueAPF().isInfinity()) {
2645  if (CFP->getValueAPF().isNegative()) {
2646  switch (Pred) {
2647  case FCmpInst::FCMP_OLT:
2648  // No value is ordered and less than negative infinity.
2649  return ConstantInt::getFalse(CFP->getContext());
2650  case FCmpInst::FCMP_UGE:
2651  // All values are unordered with or at least negative infinity.
2652  return ConstantInt::getTrue(CFP->getContext());
2653  default:
2654  break;
2655  }
2656  } else {
2657  switch (Pred) {
2658  case FCmpInst::FCMP_OGT:
2659  // No value is ordered and greater than infinity.
2660  return ConstantInt::getFalse(CFP->getContext());
2661  case FCmpInst::FCMP_ULE:
2662  // All values are unordered with and at most infinity.
2663  return ConstantInt::getTrue(CFP->getContext());
2664  default:
2665  break;
2666  }
2667  }
2668  }
2669  }
2670  }
2671 
2672  // If the comparison is with the result of a select instruction, check whether
2673  // comparing with either branch of the select always yields the same value.
2674  if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2675  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2676  return V;
2677 
2678  // If the comparison is with the result of a phi instruction, check whether
2679  // doing the compare with each incoming phi value yields a common result.
2680  if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2681  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2682  return V;
2683 
2684  return 0;
2685 }
2686 
2688  const DataLayout *TD,
2689  const TargetLibraryInfo *TLI,
2690  const DominatorTree *DT) {
2691  return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2692  RecursionLimit);
2693 }
2694 
2695 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
2696 /// the result. If not, this returns null.
2697 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
2698  Value *FalseVal, const Query &Q,
2699  unsigned MaxRecurse) {
2700  // select true, X, Y -> X
2701  // select false, X, Y -> Y
2702  if (ConstantInt *CB = dyn_cast<ConstantInt>(CondVal))
2703  return CB->getZExtValue() ? TrueVal : FalseVal;
2704 
2705  // select C, X, X -> X
2706  if (TrueVal == FalseVal)
2707  return TrueVal;
2708 
2709  if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
2710  if (isa<Constant>(TrueVal))
2711  return TrueVal;
2712  return FalseVal;
2713  }
2714  if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
2715  return FalseVal;
2716  if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
2717  return TrueVal;
2718 
2719  return 0;
2720 }
2721 
2722 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
2723  const DataLayout *TD,
2724  const TargetLibraryInfo *TLI,
2725  const DominatorTree *DT) {
2726  return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Query (TD, TLI, DT),
2727  RecursionLimit);
2728 }
2729 
2730 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
2731 /// fold the result. If not, this returns null.
2732 static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
2733  // The type of the GEP pointer operand.
2734  PointerType *PtrTy = dyn_cast<PointerType>(Ops[0]->getType());
2735  // The GEP pointer operand is not a pointer, it's a vector of pointers.
2736  if (!PtrTy)
2737  return 0;
2738 
2739  // getelementptr P -> P.
2740  if (Ops.size() == 1)
2741  return Ops[0];
2742 
2743  if (isa<UndefValue>(Ops[0])) {
2744  // Compute the (pointer) type returned by the GEP instruction.
2745  Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
2746  Type *GEPTy = PointerType::get(LastType, PtrTy->getAddressSpace());
2747  return UndefValue::get(GEPTy);
2748  }
2749 
2750  if (Ops.size() == 2) {
2751  // getelementptr P, 0 -> P.
2752  if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1]))
2753  if (C->isZero())
2754  return Ops[0];
2755  // getelementptr P, N -> P if P points to a type of zero size.
2756  if (Q.TD) {
2757  Type *Ty = PtrTy->getElementType();
2758  if (Ty->isSized() && Q.TD->getTypeAllocSize(Ty) == 0)
2759  return Ops[0];
2760  }
2761  }
2762 
2763  // Check to see if this is constant foldable.
2764  for (unsigned i = 0, e = Ops.size(); i != e; ++i)
2765  if (!isa<Constant>(Ops[i]))
2766  return 0;
2767 
2768  return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
2769 }
2770 
2772  const TargetLibraryInfo *TLI,
2773  const DominatorTree *DT) {
2774  return ::SimplifyGEPInst(Ops, Query (TD, TLI, DT), RecursionLimit);
2775 }
2776 
2777 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
2778 /// can fold the result. If not, this returns null.
2780  ArrayRef<unsigned> Idxs, const Query &Q,
2781  unsigned) {
2782  if (Constant *CAgg = dyn_cast<Constant>(Agg))
2783  if (Constant *CVal = dyn_cast<Constant>(Val))
2784  return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
2785 
2786  // insertvalue x, undef, n -> x
2787  if (match(Val, m_Undef()))
2788  return Agg;
2789 
2790  // insertvalue x, (extractvalue y, n), n
2791  if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
2792  if (EV->getAggregateOperand()->getType() == Agg->getType() &&
2793  EV->getIndices() == Idxs) {
2794  // insertvalue undef, (extractvalue y, n), n -> y
2795  if (match(Agg, m_Undef()))
2796  return EV->getAggregateOperand();
2797 
2798  // insertvalue y, (extractvalue y, n), n -> y
2799  if (Agg == EV->getAggregateOperand())
2800  return Agg;
2801  }
2802 
2803  return 0;
2804 }
2805 
2807  ArrayRef<unsigned> Idxs,
2808  const DataLayout *TD,
2809  const TargetLibraryInfo *TLI,
2810  const DominatorTree *DT) {
2811  return ::SimplifyInsertValueInst(Agg, Val, Idxs, Query (TD, TLI, DT),
2812  RecursionLimit);
2813 }
2814 
2815 /// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
2816 static Value *SimplifyPHINode(PHINode *PN, const Query &Q) {
2817  // If all of the PHI's incoming values are the same then replace the PHI node
2818  // with the common value.
2819  Value *CommonValue = 0;
2820  bool HasUndefInput = false;
2821  for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
2822  Value *Incoming = PN->getIncomingValue(i);
2823  // If the incoming value is the phi node itself, it can safely be skipped.
2824  if (Incoming == PN) continue;
2825  if (isa<UndefValue>(Incoming)) {
2826  // Remember that we saw an undef value, but otherwise ignore them.
2827  HasUndefInput = true;
2828  continue;
2829  }
2830  if (CommonValue && Incoming != CommonValue)
2831  return 0; // Not the same, bail out.
2832  CommonValue = Incoming;
2833  }
2834 
2835  // If CommonValue is null then all of the incoming values were either undef or
2836  // equal to the phi node itself.
2837  if (!CommonValue)
2838  return UndefValue::get(PN->getType());
2839 
2840  // If we have a PHI node like phi(X, undef, X), where X is defined by some
2841  // instruction, we cannot return X as the result of the PHI node unless it
2842  // dominates the PHI block.
2843  if (HasUndefInput)
2844  return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : 0;
2845 
2846  return CommonValue;
2847 }
2848 
2849 static Value *SimplifyTruncInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
2850  if (Constant *C = dyn_cast<Constant>(Op))
2851  return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.TD, Q.TLI);
2852 
2853  return 0;
2854 }
2855 
2857  const TargetLibraryInfo *TLI,
2858  const DominatorTree *DT) {
2859  return ::SimplifyTruncInst(Op, Ty, Query (TD, TLI, DT), RecursionLimit);
2860 }
2861 
2862 //=== Helper functions for higher up the class hierarchy.
2863 
2864 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
2865 /// fold the result. If not, this returns null.
2866 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2867  const Query &Q, unsigned MaxRecurse) {
2868  switch (Opcode) {
2869  case Instruction::Add:
2870  return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2871  Q, MaxRecurse);
2872  case Instruction::FAdd:
2873  return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2874 
2875  case Instruction::Sub:
2876  return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2877  Q, MaxRecurse);
2878  case Instruction::FSub:
2879  return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2880 
2881  case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse);
2882  case Instruction::FMul:
2883  return SimplifyFMulInst (LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2884  case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
2885  case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
2886  case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, Q, MaxRecurse);
2887  case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
2888  case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
2889  case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, Q, MaxRecurse);
2890  case Instruction::Shl:
2891  return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2892  Q, MaxRecurse);
2893  case Instruction::LShr:
2894  return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
2895  case Instruction::AShr:
2896  return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
2897  case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
2898  case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse);
2899  case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
2900  default:
2901  if (Constant *CLHS = dyn_cast<Constant>(LHS))
2902  if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
2903  Constant *COps[] = {CLHS, CRHS};
2904  return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.TD,
2905  Q.TLI);
2906  }
2907 
2908  // If the operation is associative, try some generic simplifications.
2909  if (Instruction::isAssociative(Opcode))
2910  if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse))
2911  return V;
2912 
2913  // If the operation is with the result of a select instruction check whether
2914  // operating on either branch of the select always yields the same value.
2915  if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2916  if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse))
2917  return V;
2918 
2919  // If the operation is with the result of a phi instruction, check whether
2920  // operating on all incoming values of the phi always yields the same value.
2921  if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2922  if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
2923  return V;
2924 
2925  return 0;
2926  }
2927 }
2928 
2929 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2930  const DataLayout *TD, const TargetLibraryInfo *TLI,
2931  const DominatorTree *DT) {
2932  return ::SimplifyBinOp(Opcode, LHS, RHS, Query (TD, TLI, DT), RecursionLimit);
2933 }
2934 
2935 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
2936 /// fold the result.
2937 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2938  const Query &Q, unsigned MaxRecurse) {
2940  return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
2941  return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
2942 }
2943 
2945  const DataLayout *TD, const TargetLibraryInfo *TLI,
2946  const DominatorTree *DT) {
2947  return ::SimplifyCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2948  RecursionLimit);
2949 }
2950 
2952  switch (ID) {
2953  default: return false;
2954 
2955  // Unary idempotent: f(f(x)) = f(x)
2956  case Intrinsic::fabs:
2957  case Intrinsic::floor:
2958  case Intrinsic::ceil:
2959  case Intrinsic::trunc:
2960  case Intrinsic::rint:
2961  case Intrinsic::nearbyint:
2962  case Intrinsic::round:
2963  return true;
2964  }
2965 }
2966 
2967 template <typename IterTy>
2968 static Value *SimplifyIntrinsic(Intrinsic::ID IID, IterTy ArgBegin, IterTy ArgEnd,
2969  const Query &Q, unsigned MaxRecurse) {
2970  // Perform idempotent optimizations
2971  if (!IsIdempotent(IID))
2972  return 0;
2973 
2974  // Unary Ops
2975  if (std::distance(ArgBegin, ArgEnd) == 1)
2976  if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin))
2977  if (II->getIntrinsicID() == IID)
2978  return II;
2979 
2980  return 0;
2981 }
2982 
2983 template <typename IterTy>
2984 static Value *SimplifyCall(Value *V, IterTy ArgBegin, IterTy ArgEnd,
2985  const Query &Q, unsigned MaxRecurse) {
2986  Type *Ty = V->getType();
2987  if (PointerType *PTy = dyn_cast<PointerType>(Ty))
2988  Ty = PTy->getElementType();
2989  FunctionType *FTy = cast<FunctionType>(Ty);
2990 
2991  // call undef -> undef
2992  if (isa<UndefValue>(V))
2993  return UndefValue::get(FTy->getReturnType());
2994 
2995  Function *F = dyn_cast<Function>(V);
2996  if (!F)
2997  return 0;
2998 
2999  if (unsigned IID = F->getIntrinsicID())
3000  if (Value *Ret =
3001  SimplifyIntrinsic((Intrinsic::ID) IID, ArgBegin, ArgEnd, Q, MaxRecurse))
3002  return Ret;
3003 
3004  if (!canConstantFoldCallTo(F))
3005  return 0;
3006 
3007  SmallVector<Constant *, 4> ConstantArgs;
3008  ConstantArgs.reserve(ArgEnd - ArgBegin);
3009  for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
3010  Constant *C = dyn_cast<Constant>(*I);
3011  if (!C)
3012  return 0;
3013  ConstantArgs.push_back(C);
3014  }
3015 
3016  return ConstantFoldCall(F, ConstantArgs, Q.TLI);
3017 }
3018 
3020  User::op_iterator ArgEnd, const DataLayout *TD,
3021  const TargetLibraryInfo *TLI,
3022  const DominatorTree *DT) {
3023  return ::SimplifyCall(V, ArgBegin, ArgEnd, Query(TD, TLI, DT),
3024  RecursionLimit);
3025 }
3026 
3028  const DataLayout *TD, const TargetLibraryInfo *TLI,
3029  const DominatorTree *DT) {
3030  return ::SimplifyCall(V, Args.begin(), Args.end(), Query(TD, TLI, DT),
3031  RecursionLimit);
3032 }
3033 
3034 /// SimplifyInstruction - See if we can compute a simplified version of this
3035 /// instruction. If not, this returns null.
3037  const TargetLibraryInfo *TLI,
3038  const DominatorTree *DT) {
3039  Value *Result;
3040 
3041  switch (I->getOpcode()) {
3042  default:
3043  Result = ConstantFoldInstruction(I, TD, TLI);
3044  break;
3045  case Instruction::FAdd:
3046  Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
3047  I->getFastMathFlags(), TD, TLI, DT);
3048  break;
3049  case Instruction::Add:
3050  Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
3051  cast<BinaryOperator>(I)->hasNoSignedWrap(),
3052  cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3053  TD, TLI, DT);
3054  break;
3055  case Instruction::FSub:
3056  Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
3057  I->getFastMathFlags(), TD, TLI, DT);
3058  break;
3059  case Instruction::Sub:
3060  Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
3061  cast<BinaryOperator>(I)->hasNoSignedWrap(),
3062  cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3063  TD, TLI, DT);
3064  break;
3065  case Instruction::FMul:
3066  Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
3067  I->getFastMathFlags(), TD, TLI, DT);
3068  break;
3069  case Instruction::Mul:
3070  Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3071  break;
3072  case Instruction::SDiv:
3073  Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3074  break;
3075  case Instruction::UDiv:
3076  Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3077  break;
3078  case Instruction::FDiv:
3079  Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3080  break;
3081  case Instruction::SRem:
3082  Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3083  break;
3084  case Instruction::URem:
3085  Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3086  break;
3087  case Instruction::FRem:
3088  Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3089  break;
3090  case Instruction::Shl:
3091  Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
3092  cast<BinaryOperator>(I)->hasNoSignedWrap(),
3093  cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3094  TD, TLI, DT);
3095  break;
3096  case Instruction::LShr:
3097  Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
3098  cast<BinaryOperator>(I)->isExact(),
3099  TD, TLI, DT);
3100  break;
3101  case Instruction::AShr:
3102  Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
3103  cast<BinaryOperator>(I)->isExact(),
3104  TD, TLI, DT);
3105  break;
3106  case Instruction::And:
3107  Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3108  break;
3109  case Instruction::Or:
3110  Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3111  break;
3112  case Instruction::Xor:
3113  Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3114  break;
3115  case Instruction::ICmp:
3116  Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
3117  I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3118  break;
3119  case Instruction::FCmp:
3120  Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
3121  I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3122  break;
3123  case Instruction::Select:
3124  Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
3125  I->getOperand(2), TD, TLI, DT);
3126  break;
3127  case Instruction::GetElementPtr: {
3128  SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
3129  Result = SimplifyGEPInst(Ops, TD, TLI, DT);
3130  break;
3131  }
3132  case Instruction::InsertValue: {
3133  InsertValueInst *IV = cast<InsertValueInst>(I);
3136  IV->getIndices(), TD, TLI, DT);
3137  break;
3138  }
3139  case Instruction::PHI:
3140  Result = SimplifyPHINode(cast<PHINode>(I), Query (TD, TLI, DT));
3141  break;
3142  case Instruction::Call: {
3143  CallSite CS(cast<CallInst>(I));
3144  Result = SimplifyCall(CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
3145  TD, TLI, DT);
3146  break;
3147  }
3148  case Instruction::Trunc:
3149  Result = SimplifyTruncInst(I->getOperand(0), I->getType(), TD, TLI, DT);
3150  break;
3151  }
3152 
3153  /// If called on unreachable code, the above logic may report that the
3154  /// instruction simplified to itself. Make life easier for users by
3155  /// detecting that case here, returning a safe value instead.
3156  return Result == I ? UndefValue::get(I->getType()) : Result;
3157 }
3158 
3159 /// \brief Implementation of recursive simplification through an instructions
3160 /// uses.
3161 ///
3162 /// This is the common implementation of the recursive simplification routines.
3163 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
3164 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
3165 /// instructions to process and attempt to simplify it using
3166 /// InstructionSimplify.
3167 ///
3168 /// This routine returns 'true' only when *it* simplifies something. The passed
3169 /// in simplified value does not count toward this.
3171  const DataLayout *TD,
3172  const TargetLibraryInfo *TLI,
3173  const DominatorTree *DT) {
3174  bool Simplified = false;
3176 
3177  // If we have an explicit value to collapse to, do that round of the
3178  // simplification loop by hand initially.
3179  if (SimpleV) {
3180  for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
3181  ++UI)
3182  if (*UI != I)
3183  Worklist.insert(cast<Instruction>(*UI));
3184 
3185  // Replace the instruction with its simplified value.
3186  I->replaceAllUsesWith(SimpleV);
3187 
3188  // Gracefully handle edge cases where the instruction is not wired into any
3189  // parent block.
3190  if (I->getParent())
3191  I->eraseFromParent();
3192  } else {
3193  Worklist.insert(I);
3194  }
3195 
3196  // Note that we must test the size on each iteration, the worklist can grow.
3197  for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
3198  I = Worklist[Idx];
3199 
3200  // See if this instruction simplifies.
3201  SimpleV = SimplifyInstruction(I, TD, TLI, DT);
3202  if (!SimpleV)
3203  continue;
3204 
3205  Simplified = true;
3206 
3207  // Stash away all the uses of the old instruction so we can check them for
3208  // recursive simplifications after a RAUW. This is cheaper than checking all
3209  // uses of To on the recursive step in most cases.
3210  for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
3211  ++UI)
3212  Worklist.insert(cast<Instruction>(*UI));
3213 
3214  // Replace the instruction with its simplified value.
3215  I->replaceAllUsesWith(SimpleV);
3216 
3217  // Gracefully handle edge cases where the instruction is not wired into any
3218  // parent block.
3219  if (I->getParent())
3220  I->eraseFromParent();
3221  }
3222  return Simplified;
3223 }
3224 
3226  const DataLayout *TD,
3227  const TargetLibraryInfo *TLI,
3228  const DominatorTree *DT) {
3229  return replaceAndRecursivelySimplifyImpl(I, 0, TD, TLI, DT);
3230 }
3231 
3233  const DataLayout *TD,
3234  const TargetLibraryInfo *TLI,
3235  const DominatorTree *DT) {
3236  assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
3237  assert(SimpleV && "Must provide a simplified value.");
3238  return replaceAndRecursivelySimplifyImpl(I, SimpleV, TD, TLI, DT);
3239 }
MaxMin_match< ICmpInst, LHS, RHS, umin_pred_ty > m_UMin(const LHS &L, const RHS &R)
Definition: PatternMatch.h:958
BinaryOp_match< LHS, RHS, Instruction::And > m_And(const LHS &L, const RHS &R)
Definition: PatternMatch.h:467
static Value * SimplifyCmpInst(unsigned, Value *, Value *, const Query &, unsigned)
APInt LLVM_ATTRIBUTE_UNUSED_RESULT ashr(unsigned shiftAmt) const
Arithmetic right-shift function.
Definition: APInt.cpp:1038
use_iterator use_end()
Definition: Value.h:152
static ConstantInt * getFalse(LLVMContext &Context)
Definition: Constants.cpp:445
class_match< Value > m_Value()
m_Value() - Match an arbitrary value and ignore it.
Definition: PatternMatch.h:70
Abstract base class of comparison instructions.
Definition: InstrTypes.h:633
class_match< UndefValue > m_Undef()
m_Undef() - Match an arbitrary undef constant.
Definition: PatternMatch.h:76
const DominatorTree * DT
void reserve(unsigned N)
Definition: SmallVector.h:425
APInt LLVM_ATTRIBUTE_UNUSED_RESULT abs() const
Get the absolute value;.
Definition: APInt.h:1521
static Value * SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, const Query &Q, unsigned MaxRecurse)
static APInt getAllOnesValue(unsigned numBits)
Get the all-ones value.
Definition: APInt.h:450
BinaryOp_match< LHS, RHS, Instruction::Sub > m_Sub(const LHS &L, const RHS &R)
Definition: PatternMatch.h:407
Value * getAggregateOperand()
static Type * makeCmpResultType(Type *opnd_type)
Create a result type for fcmp/icmp.
Definition: InstrTypes.h:832
ArrayRef< unsigned > getIndices() const
Value * SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
unsigned getScalarSizeInBits()
Definition: Type.cpp:135
bool canConstantFoldCallTo(const Function *F)
IterTy arg_end() const
Definition: CallSite.h:143
bool isReachableFromEntry(const BasicBlock *A) const
Definition: Dominators.h:879
BinaryOp_match< LHS, RHS, Instruction::SRem > m_SRem(const LHS &L, const RHS &R)
Definition: PatternMatch.h:455
match_zero m_Zero()
Definition: PatternMatch.h:137
enable_if_c<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:266
unsigned getBitWidth() const
getBitWidth - Return the bitwidth of this constant.
Definition: Constants.h:110
This class represents zero extension of integer types.
Value * SimplifyFSubInst(Value *LHS, Value *RHS, FastMathFlags FMF, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
static bool isOrdered(unsigned short predicate)
Determine if the predicate is an ordered operation.
BinaryOp_match< LHS, RHS, Instruction::Mul > m_Mul(const LHS &L, const RHS &R)
Definition: PatternMatch.h:419
static Constant * getGetElementPtr(Constant *C, ArrayRef< Constant * > IdxList, bool InBounds=false)
Definition: Constants.h:1004
iterator end() const
Definition: ArrayRef.h:98
static Value * SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS, const Query &Q, unsigned MaxRecurse)
Predicate getInversePredicate() const
Return the inverse of the instruction's predicate.
Definition: InstrTypes.h:737
static PointerType * get(Type *ElementType, unsigned AddressSpace)
Definition: Type.cpp:730
unsigned less or equal
Definition: InstrTypes.h:677
unsigned less than
Definition: InstrTypes.h:676
BinaryOp_match< LHS, RHS, Instruction::AShr > m_AShr(const LHS &L, const RHS &R)
Definition: PatternMatch.h:497
bool insert(PtrType Ptr)
Definition: SmallPtrSet.h:253
Value * SimplifyAddInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
bool isKnownNonNull(const Value *V, const TargetLibraryInfo *TLI=0)
bool isSigned() const
Determine if this instruction is using a signed comparison.
Definition: InstrTypes.h:780
0 1 0 0 True if ordered and less than
Definition: InstrTypes.h:657
FastMathFlags getFastMathFlags() const
const Function * getParent() const
Return the enclosing method, or null if none.
Definition: BasicBlock.h:116
F(f)
static Value * FactorizeBinOp(unsigned Opcode, Value *LHS, Value *RHS, unsigned OpcToExtract, const Query &Q, unsigned MaxRecurse)
This class represents a sign extension of integer types.
unsigned getAddressSpace() const
Return the address space of the Pointer type.
Definition: DerivedTypes.h:445
BinaryOp_match< LHS, RHS, Instruction::FSub > m_FSub(const LHS &L, const RHS &R)
Definition: PatternMatch.h:413
Value * SimplifyInsertValueInst(Value *Agg, Value *Val, ArrayRef< unsigned > Idxs, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
static Constant * getTrue(Type *Ty)
static Constant * getSub(Constant *C1, Constant *C2, bool HasNUW=false, bool HasNSW=false)
Definition: Constants.cpp:2040
static Value * SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, const Query &Q, unsigned MaxRecurse)
static Constant * computePointerDifference(const DataLayout *TD, Value *LHS, Value *RHS)
Compute the constant difference between two pointer values. If the difference is not a constant...
Value * SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
static Value * SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact, const Query &Q, unsigned MaxRecurse)
size_type size() const
Determine the number of elements in the SetVector.
Definition: SetVector.h:64
Value * SimplifyUDivInst(Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
op_iterator op_begin()
Definition: User.h:116
static APInt getSignedMaxValue(unsigned numBits)
Gets maximum signed value of APInt for a specific bit width.
Definition: APInt.h:423
LoopInfoBase< BlockT, LoopT > * LI
Definition: LoopInfoImpl.h:411
Value * SimplifySDivInst(Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
static Constant * getNullValue(Type *Ty)
Definition: Constants.cpp:111
static Constant * getAdd(Constant *C1, Constant *C2, bool HasNUW=false, bool HasNSW=false)
Definition: Constants.cpp:2029
bool isNegative() const
Determine sign of this APInt.
Definition: APInt.h:322
static Value * ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS, const Query &Q, unsigned MaxRecurse)
bool match(Val *V, const Pattern &P)
Definition: PatternMatch.h:42
static Value * SimplifySDivInst(Value *Op0, Value *Op1, const Query &Q, unsigned MaxRecurse)
bool hasNoNaNs() const
Determine whether the no-NaNs flag is set.
static Value * SimplifyFDivInst(Value *Op0, Value *Op1, const Query &Q, unsigned)
static Constant * getIntegerCast(Constant *C, Type *Ty, bool isSigned)
Create a ZExt, Bitcast or Trunc for integer -> integer casts.
Definition: Constants.cpp:1502
Value * SimplifyAndInst(Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
const APInt & getValue() const
Return the constant's value.
Definition: Constants.h:105
Exact_match< T > m_Exact(const T &SubPattern)
Definition: PatternMatch.h:564
BinOp2_match< LHS, RHS, Instruction::LShr, Instruction::AShr > m_Shr(const LHS &L, const RHS &R)
m_Shr - Matches LShr or AShr.
Definition: PatternMatch.h:528
#define llvm_unreachable(msg)
Definition: Use.h:60
APInt LLVM_ATTRIBUTE_UNUSED_RESULT lshr(unsigned shiftAmt) const
Logical right-shift function.
Definition: APInt.cpp:1127
CastClass_match< OpTy, Instruction::Trunc > m_Trunc(const OpTy &Op)
m_Trunc
Definition: PatternMatch.h:678
static Value * SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, const Query &Q, unsigned MaxRecurse)
ID
LLVM Calling Convention Representation.
Definition: CallingConv.h:26
bool replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
Replace all uses of 'I' with 'SimpleV' and simplify the uses recursively.
static Value * SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, const Query &Q, unsigned MaxRecurse)
static Value * SimplifyOrInst(Value *, Value *, const Query &, unsigned)
not_match< LHS > m_Not(const LHS &L)
Definition: PatternMatch.h:738
BinaryOp_match< LHS, RHS, Instruction::Add > m_Add(const LHS &L, const RHS &R)
Definition: PatternMatch.h:395
This class represents a cast from a pointer to an integer.
static Value * SimplifyGEPInst(ArrayRef< Value * > Ops, const Query &Q, unsigned)
static Constant * stripAndComputeConstantOffsets(const DataLayout *TD, Value *&V, bool AllowNonInbounds=false)
Compute the base pointer and cumulative constant offsets for V.
static Value * SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF, const Query &Q, unsigned MaxRecurse)
static Value * SimplifyBinOp(unsigned, Value *, Value *, const Query &, unsigned)
bool insert(const value_type &X)
Insert a new element into the SetVector.
Definition: SetVector.h:102
bool contains(const APInt &Val) const
static Value * ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred, Value *LHS, Value *RHS)
bool isAssociative() const
static Value * SimplifyPHINode(PHINode *PN, const Query &Q)
SimplifyPHINode - See if we can fold the given phi. If not, returns null.
ArrayRef< T > slice(unsigned N) const
slice(n) - Chop off the first N elements of the array.
Definition: ArrayRef.h:134
static Constant * getICmp(unsigned short pred, Constant *LHS, Constant *RHS)
Definition: Constants.cpp:1870
Value * SimplifyFMulInst(Value *LHS, Value *RHS, FastMathFlags FMF, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
MaxMin_match< ICmpInst, LHS, RHS, smin_pred_ty > m_SMin(const LHS &L, const RHS &R)
Definition: PatternMatch.h:946
STATISTIC(NumExpand,"Number of expansions")
static Value * SimplifyTruncInst(Value *, Type *, const Query &, unsigned)
const DataLayout * TD
Value * getInsertedValueOperand()
class_match< ConstantInt > m_ConstantInt()
m_ConstantInt() - Match an arbitrary ConstantInt and ignore it.
Definition: PatternMatch.h:72
Constant * ConstantFoldInstruction(Instruction *I, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0)
Predicate getUnsignedPredicate() const
Return the unsigned version of the predicate.
Definition: Instructions.h:987
static Value * SimplifyAndInst(Value *, Value *, const Query &, unsigned)
Constant * ConstantFoldInsertValueInstruction(Constant *Agg, Constant *Val, ArrayRef< unsigned > Idxs)
ValTy * getCalledValue() const
Definition: CallSite.h:85
void replaceAllUsesWith(Value *V)
Definition: Value.cpp:303
static Value * ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS, const Query &Q, unsigned MaxRecurse)
static Value * SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF, const Query &Q, unsigned MaxRecurse)
static Constant * getIntToPtr(Constant *C, Type *Ty)
Definition: Constants.cpp:1649
Query(const DataLayout *td, const TargetLibraryInfo *tli, const DominatorTree *dt)
Value * SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
Type * getElementType() const
Definition: DerivedTypes.h:319
size_t size() const
size - Get the array size.
Definition: ArrayRef.h:109
Value * SimplifyGEPInst(ArrayRef< Value * > Ops, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
static Value * SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q, unsigned MaxRecurse)
bool ult(const APInt &RHS) const
Unsigned less than comparison.
Definition: APInt.cpp:515
unsigned getNumIncomingValues() const
Constant * ConstantFoldCall(Function *F, ArrayRef< Constant * > Operands, const TargetLibraryInfo *TLI=0)
#define P(N)
BinaryOp_match< LHS, RHS, Instruction::LShr > m_LShr(const LHS &L, const RHS &R)
Definition: PatternMatch.h:491
static Constant * computePointerICmp(const DataLayout *TD, const TargetLibraryInfo *TLI, CmpInst::Predicate Pred, Value *LHS, Value *RHS)
MaxMin_match< ICmpInst, LHS, RHS, umax_pred_ty > m_UMax(const LHS &L, const RHS &R)
Definition: PatternMatch.h:952
BinaryOp_match< LHS, RHS, Instruction::SDiv > m_SDiv(const LHS &L, const RHS &R)
Definition: PatternMatch.h:437
static Value * SimplifySelectInst(Value *CondVal, Value *TrueVal, Value *FalseVal, const Query &Q, unsigned MaxRecurse)
bool isFullSet() const
BinaryOp_match< LHS, RHS, Instruction::Or > m_Or(const LHS &L, const RHS &R)
Definition: PatternMatch.h:473
bool isVectorTy() const
Definition: Type.h:229
const TargetLibraryInfo * TLI
unsigned getIntrinsicID() const LLVM_READONLY
Definition: Function.cpp:371
bool isEquality() const
LLVM Constant Representation.
Definition: Constant.h:41
static Value * SimplifyCall(Value *V, IterTy ArgBegin, IterTy ArgEnd, const Query &Q, unsigned MaxRecurse)
const Value * getCondition() const
static Value * ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS, Value *RHS, const Query &Q, unsigned MaxRecurse)
static Value * SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q, unsigned MaxRecurse)
APInt Or(const APInt &LHS, const APInt &RHS)
Bitwise OR function for APInt.
Definition: APInt.h:1845
static Value * SimplifyFMulInst(Value *Op0, Value *Op1, FastMathFlags FMF, const Query &Q, unsigned MaxRecurse)
Given the operands for an FMul, see if we can fold the result.
APInt Xor(const APInt &LHS, const APInt &RHS)
Bitwise XOR function for APInt.
Definition: APInt.h:1850
static Value * SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1, const Query &Q, unsigned MaxRecurse)
cst_pred_ty< is_all_ones > m_AllOnes()
m_AllOnes() - Match an integer or vector with all bits set to true.
Definition: PatternMatch.h:265
bool isIntPredicate() const
Definition: InstrTypes.h:730
specificval_ty m_Specific(const Value *V)
m_Specific - Match if we have a specific specified value.
Definition: PatternMatch.h:323
op_iterator op_end()
Definition: User.h:118
BinaryOp_match< LHS, RHS, Instruction::Shl > m_Shl(const LHS &L, const RHS &R)
Definition: PatternMatch.h:485
bool isFalseWhenEqual() const
Determine if this is false when both operands are the same.
Definition: InstrTypes.h:798
iterator begin() const
Definition: ArrayRef.h:97
Value * SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
APInt LLVM_ATTRIBUTE_UNUSED_RESULT sdiv(const APInt &RHS) const
Signed division function for APInt.
Definition: APInt.cpp:1879
Value * getOperand(unsigned i) const
Definition: User.h:88
bool isCommutative() const
Definition: Instruction.h:269
Constant * ConstantFoldCompareInstOperands(unsigned Predicate, Constant *LHS, Constant *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0)
Predicate getPredicate() const
Return the predicate for this instruction.
Definition: InstrTypes.h:714
static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT)
ValueDominatesPHI - Does the given value dominate the specified phi node?
static Constant * getAllOnesValue(Type *Ty)
Get the all ones value.
Definition: Constants.cpp:163
1 1 1 1 Always true (always folded)
Definition: InstrTypes.h:668
bool dominates(const DomTreeNode *A, const DomTreeNode *B) const
Definition: Dominators.h:801
static Value * SimplifyInsertValueInst(Value *Agg, Value *Val, ArrayRef< unsigned > Idxs, const Query &Q, unsigned)
match_combine_or< match_zero, match_neg_zero > m_AnyZero()
Definition: PatternMatch.h:157
bool isEmptySet() const
bool isPointerTy() const
Definition: Type.h:220
static UndefValue * get(Type *T)
Definition: Constants.cpp:1334
Value * SimplifyInstruction(Instruction *I, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
LLVMContext & getContext() const
All values hold a context through their type.
Definition: Value.cpp:517
bool hasNoSignedWrap() const
hasNoSignedWrap - Determine whether the no signed wrap flag is set.
const Value * getTrueValue() const
1 1 0 1 True if unordered, less than, or equal
Definition: InstrTypes.h:666
Value * SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
signed greater than
Definition: InstrTypes.h:678
static Value * ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS, unsigned OpcToExpand, const Query &Q, unsigned MaxRecurse)
neg_match< LHS > m_Neg(const LHS &L)
m_Neg - Match an integer negate.
Definition: PatternMatch.h:764
IntegerType * getIntPtrType(LLVMContext &C, unsigned AddressSpace=0) const
Definition: DataLayout.cpp:610
static Value * SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q, unsigned MaxRecurse)
0 0 1 0 True if ordered and greater than
Definition: InstrTypes.h:655
BinaryOps getOpcode() const
Definition: InstrTypes.h:326
static Constant * getSplat(unsigned NumElts, Constant *Elt)
Definition: Constants.cpp:1021
static IntegerType * get(LLVMContext &C, unsigned NumBits)
Get or create an IntegerType instance.
Definition: Type.cpp:305
A SetVector that performs no allocations if smaller than a certain size.
Definition: SetVector.h:218
static Value * SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1, const Query &Q, unsigned MaxRecurse)
unsigned getIntegerBitWidth() const
Definition: Type.cpp:178
Class for constant integers.
Definition: Constants.h:51
static Value * SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, const Query &Q, unsigned MaxRecurse)
Value * getIncomingValue(unsigned i) const
uint64_t getTypeAllocSize(Type *Ty) const
Definition: DataLayout.h:326
unsigned getVectorNumElements() const
Definition: Type.cpp:214
ConstantRange inverse() const
Type * getType() const
Definition: Value.h:111
BinaryOp_match< LHS, RHS, Instruction::URem > m_URem(const LHS &L, const RHS &R)
Definition: PatternMatch.h:449
BinaryOp_match< LHS, RHS, Instruction::UDiv > m_UDiv(const LHS &L, const RHS &R)
Definition: PatternMatch.h:431
signed less than
Definition: InstrTypes.h:680
bool isTrueWhenEqual() const
Determine if this is true when both operands are the same.
Definition: InstrTypes.h:792
bool isKnownToBeAPowerOfTwo(Value *V, bool OrZero=false, unsigned Depth=0)
Value * stripPointerCasts()
Strips off any unneeded pointer casts, all-zero GEPs and aliases from the specified value...
Definition: Value.cpp:385
Predicate getSwappedPredicate() const
Return the predicate as if the operands were swapped.
Definition: InstrTypes.h:753
static Constant * get(Type *Ty, uint64_t V, bool isSigned=false)
Definition: Constants.cpp:492
bool isZero() const
Definition: Constants.h:160
static Value * SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1, const Query &Q, unsigned MaxRecurse)
static Constant * getTrunc(Constant *C, Type *Ty)
Definition: Constants.cpp:1527
const BasicBlock & getEntryBlock() const
Definition: Function.h:380
Value * SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
bool isNullValue() const
Definition: Constants.cpp:75
bool isExact() const
isExact - Determine whether the exact flag is set.
Value * SimplifyXorInst(Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
static ConstantInt * getTrue(LLVMContext &Context)
Definition: Constants.cpp:438
void swap(llvm::BitVector &LHS, llvm::BitVector &RHS)
Implement std::swap in terms of BitVector swap.
Definition: BitVector.h:591
signed less or equal
Definition: InstrTypes.h:681
Class for arbitrary precision integers.
Definition: APInt.h:75
static Value * SimplifyIntrinsic(Intrinsic::ID IID, IterTy ArgBegin, IterTy ArgEnd, const Query &Q, unsigned MaxRecurse)
static Constant * getFalse(Type *Ty)
bool isIntegerTy() const
Definition: Type.h:196
bool noNaNs()
Flag queries.
Definition: Operator.h:195
CastClass_match< OpTy, Instruction::PtrToInt > m_PtrToInt(const OpTy &Op)
m_PtrToInt
Definition: PatternMatch.h:671
static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV, const DataLayout *TD, const TargetLibraryInfo *TLI, const DominatorTree *DT)
Implementation of recursive simplification through an instructions uses.
bool isMinValue() const
Determine if this is the smallest unsigned value.
Definition: APInt.h:365
bool isFPPredicate() const
Definition: InstrTypes.h:729
APInt And(const APInt &LHS, const APInt &RHS)
Bitwise AND function for APInt.
Definition: APInt.h:1840
unsigned getOpcode() const
Definition: Operator.h:51
void ComputeSignBit(Value *V, bool &KnownZero, bool &KnownOne, const DataLayout *TD=0, unsigned Depth=0)
use_iterator use_begin()
Definition: Value.h:150
specific_fpval m_FPOne()
Match a float 1.0 or vector with all elements equal to 1.0.
Definition: PatternMatch.h:348
Value * SimplifySRemInst(Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
Value * SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
APInt LLVM_ATTRIBUTE_UNUSED_RESULT udiv(const APInt &RHS) const
Unsigned division operation.
Definition: APInt.cpp:1842
unsigned greater or equal
Definition: InstrTypes.h:675
Value * SimplifyOrInst(Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
static Value * SimplifyFRemInst(Value *Op0, Value *Op1, const Query &, unsigned)
#define I(x, y, z)
Definition: MD5.cpp:54
bool hasNoInfs() const
Determine whether the no-infs flag is set.
MaxMin_match< ICmpInst, LHS, RHS, smax_pred_ty > m_SMax(const LHS &L, const RHS &R)
Definition: PatternMatch.h:940
static Value * SimplifyMulInst(Value *Op0, Value *Op1, const Query &Q, unsigned MaxRecurse)
static ConstantRange makeConstantRange(Predicate pred, const APInt &C)
Make a ConstantRange for a relation with a constant value.
const Type * getScalarType() const
Definition: Type.cpp:51
unsigned getPrimitiveSizeInBits() const
Definition: Type.cpp:117
static bool IsIdempotent(Intrinsic::ID ID)
IterTy arg_begin() const
Definition: CallSite.h:137
static Value * SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, const Query &Q, unsigned MaxRecurse)
Value * SimplifyFDivInst(Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
BinOp2_match< LHS, RHS, Instruction::SDiv, Instruction::UDiv > m_IDiv(const LHS &L, const RHS &R)
m_IDiv - Matches UDiv and SDiv.
Definition: PatternMatch.h:542
bool CannotBeNegativeZero(const Value *V, unsigned Depth=0)
bool isUnsigned() const
Determine if this instruction is using an unsigned comparison.
Definition: InstrTypes.h:786
bool noSignedZeros()
Definition: Operator.h:197
match_neg_zero m_NegZero()
Definition: PatternMatch.h:152
Type * getReturnType() const
Definition: DerivedTypes.h:121
static Type * getIndexedType(Type *Ptr, ArrayRef< Value * > IdxList)
static APInt getSignedMinValue(unsigned numBits)
Gets minimum signed value of APInt for a specific bit width.
Definition: APInt.h:433
Value * SimplifyURemInst(Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
LLVM Value Representation.
Definition: Value.h:66
bool hasNoUnsignedWrap() const
hasNoUnsignedWrap - Determine whether the no unsigned wrap flag is set.
1 0 1 1 True if unordered, greater than, or equal
Definition: InstrTypes.h:664
unsigned getOpcode() const
getOpcode() returns a member of one of the enums like Instruction::Add.
Definition: Instruction.h:83
cst_pred_ty< is_one > m_One()
m_One() - Match an integer 1 or a vector with all elements equal to 1.
Definition: PatternMatch.h:257
Value * SimplifyCall(Value *V, User::op_iterator ArgBegin, User::op_iterator ArgEnd, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
Given a function and iterators over arguments, see if we can fold the result.
Value * SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
bool isKnownNonZero(Value *V, const DataLayout *TD=0, unsigned Depth=0)
static bool isUnordered(unsigned short predicate)
Determine if the predicate is an unordered operation.
Constant * ConstantFoldInstOperands(unsigned Opcode, Type *DestTy, ArrayRef< Constant * > Ops, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0)
bool isSized() const
Definition: Type.h:278
uint64_t getTypeSizeInBits(Type *Ty) const
Definition: DataLayout.h:459
static Value * ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS, const Query &Q, unsigned MaxRecurse)
Predicate getSignedPredicate() const
Return the signed version of the predicate.
Definition: Instructions.h:975
const Value * getFalseValue() const
Convenience struct for specifying and reasoning about fast-math flags.
Definition: Operator.h:170
unsigned greater than
Definition: InstrTypes.h:674
Value * SimplifyFRemInst(Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
Value * SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
static GCMetadataPrinterRegistry::Add< OcamlGCMetadataPrinter > Y("ocaml","ocaml 3.10-compatible collector")
bool getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout *DL, const TargetLibraryInfo *TLI, bool RoundToAlign=false)
Compute the size of the object pointed by Ptr. Returns true and the object size in Size if successful...
static APInt getNullValue(unsigned numBits)
Get the '0' value.
Definition: APInt.h:457
static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS, Value *RHS)
isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
Value * SimplifySubInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
static Constant * getCast(unsigned ops, Constant *C, Type *Ty)
Definition: Constants.cpp:1444
static Value * SimplifyXorInst(Value *, Value *, const Query &, unsigned)
static RegisterPass< NVPTXAllocaHoisting > X("alloca-hoisting","Hoisting alloca instructions in non-entry ""blocks to the entry block")
const BasicBlock * getParent() const
Definition: Instruction.h:52
INITIALIZE_PASS(GlobalMerge,"global-merge","Global Merge", false, false) bool GlobalMerge const DataLayout * TD
static Type * GetCompareTy(Value *Op)
bool hasNoUnsignedWrap() const
Definition: Operator.h:101
Value * SimplifyMulInst(Value *LHS, Value *RHS, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
0 0 0 0 Always false (always folded)
Definition: InstrTypes.h:653
signed greater or equal
Definition: InstrTypes.h:679
Value * SimplifyFAddInst(Value *LHS, Value *RHS, FastMathFlags FMF, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
bool recursivelySimplifyInstruction(Instruction *I, const DataLayout *TD=0, const TargetLibraryInfo *TLI=0, const DominatorTree *DT=0)
Recursively attempt to simplify an instruction.