LLVM  6.0.0svn
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 
21 #include "llvm/ADT/SetVector.h"
22 #include "llvm/ADT/Statistic.h"
32 #include "llvm/IR/ConstantRange.h"
33 #include "llvm/IR/DataLayout.h"
34 #include "llvm/IR/Dominators.h"
36 #include "llvm/IR/GlobalAlias.h"
37 #include "llvm/IR/Operator.h"
38 #include "llvm/IR/PatternMatch.h"
39 #include "llvm/IR/ValueHandle.h"
40 #include "llvm/Support/KnownBits.h"
41 #include <algorithm>
42 using namespace llvm;
43 using namespace llvm::PatternMatch;
44 
45 #define DEBUG_TYPE "instsimplify"
46 
47 enum { RecursionLimit = 3 };
48 
49 STATISTIC(NumExpand, "Number of expansions");
50 STATISTIC(NumReassoc, "Number of reassociations");
51 
52 static Value *SimplifyAndInst(Value *, Value *, const SimplifyQuery &, unsigned);
53 static Value *SimplifyBinOp(unsigned, Value *, Value *, const SimplifyQuery &,
54  unsigned);
55 static Value *SimplifyFPBinOp(unsigned, Value *, Value *, const FastMathFlags &,
56  const SimplifyQuery &, unsigned);
57 static Value *SimplifyCmpInst(unsigned, Value *, Value *, const SimplifyQuery &,
58  unsigned);
59 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
60  const SimplifyQuery &Q, unsigned MaxRecurse);
61 static Value *SimplifyOrInst(Value *, Value *, const SimplifyQuery &, unsigned);
62 static Value *SimplifyXorInst(Value *, Value *, const SimplifyQuery &, unsigned);
63 static Value *SimplifyCastInst(unsigned, Value *, Type *,
64  const SimplifyQuery &, unsigned);
65 
66 /// For a boolean type or a vector of boolean type, return false or a vector
67 /// with every element false.
68 static Constant *getFalse(Type *Ty) {
69  return ConstantInt::getFalse(Ty);
70 }
71 
72 /// For a boolean type or a vector of boolean type, return true or a vector
73 /// with every element true.
74 static Constant *getTrue(Type *Ty) {
75  return ConstantInt::getTrue(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 /// 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  return DT->dominates(I, P);
108 
109  // Otherwise, if the instruction is in the entry block and is not an invoke,
110  // then it obviously dominates all phi nodes.
111  if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
112  !isa<InvokeInst>(I))
113  return true;
114 
115  return false;
116 }
117 
118 /// Simplify "A op (B op' C)" by distributing op over op', turning it into
119 /// "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
120 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
121 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
122 /// Returns the simplified value, or null if no simplification was performed.
124  Instruction::BinaryOps OpcodeToExpand,
125  const SimplifyQuery &Q, unsigned MaxRecurse) {
126  // Recursion is always used, so bail out at once if we already hit the limit.
127  if (!MaxRecurse--)
128  return nullptr;
129 
130  // Check whether the expression has the form "(A op' B) op C".
131  if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
132  if (Op0->getOpcode() == OpcodeToExpand) {
133  // It does! Try turning it into "(A op C) op' (B op C)".
134  Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
135  // Do "A op C" and "B op C" both simplify?
136  if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
137  if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
138  // They do! Return "L op' R" if it simplifies or is already available.
139  // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
140  if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
141  && L == B && R == A)) {
142  ++NumExpand;
143  return LHS;
144  }
145  // Otherwise return "L op' R" if it simplifies.
146  if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
147  ++NumExpand;
148  return V;
149  }
150  }
151  }
152 
153  // Check whether the expression has the form "A op (B op' C)".
154  if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
155  if (Op1->getOpcode() == OpcodeToExpand) {
156  // It does! Try turning it into "(A op B) op' (A op C)".
157  Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
158  // Do "A op B" and "A op C" both simplify?
159  if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
160  if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
161  // They do! Return "L op' R" if it simplifies or is already available.
162  // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
163  if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
164  && L == C && R == B)) {
165  ++NumExpand;
166  return RHS;
167  }
168  // Otherwise return "L op' R" if it simplifies.
169  if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
170  ++NumExpand;
171  return V;
172  }
173  }
174  }
175 
176  return nullptr;
177 }
178 
179 /// Generic simplifications for associative binary operations.
180 /// Returns the simpler value, or null if none was found.
182  Value *LHS, Value *RHS,
183  const SimplifyQuery &Q,
184  unsigned MaxRecurse) {
185  assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
186 
187  // Recursion is always used, so bail out at once if we already hit the limit.
188  if (!MaxRecurse--)
189  return nullptr;
190 
193 
194  // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
195  if (Op0 && Op0->getOpcode() == Opcode) {
196  Value *A = Op0->getOperand(0);
197  Value *B = Op0->getOperand(1);
198  Value *C = RHS;
199 
200  // Does "B op C" simplify?
201  if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
202  // It does! Return "A op V" if it simplifies or is already available.
203  // If V equals B then "A op V" is just the LHS.
204  if (V == B) return LHS;
205  // Otherwise return "A op V" if it simplifies.
206  if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
207  ++NumReassoc;
208  return W;
209  }
210  }
211  }
212 
213  // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
214  if (Op1 && Op1->getOpcode() == Opcode) {
215  Value *A = LHS;
216  Value *B = Op1->getOperand(0);
217  Value *C = Op1->getOperand(1);
218 
219  // Does "A op B" simplify?
220  if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
221  // It does! Return "V op C" if it simplifies or is already available.
222  // If V equals B then "V op C" is just the RHS.
223  if (V == B) return RHS;
224  // Otherwise return "V op C" if it simplifies.
225  if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
226  ++NumReassoc;
227  return W;
228  }
229  }
230  }
231 
232  // The remaining transforms require commutativity as well as associativity.
233  if (!Instruction::isCommutative(Opcode))
234  return nullptr;
235 
236  // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
237  if (Op0 && Op0->getOpcode() == Opcode) {
238  Value *A = Op0->getOperand(0);
239  Value *B = Op0->getOperand(1);
240  Value *C = RHS;
241 
242  // Does "C op A" simplify?
243  if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
244  // It does! Return "V op B" if it simplifies or is already available.
245  // If V equals A then "V op B" is just the LHS.
246  if (V == A) return LHS;
247  // Otherwise return "V op B" if it simplifies.
248  if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
249  ++NumReassoc;
250  return W;
251  }
252  }
253  }
254 
255  // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
256  if (Op1 && Op1->getOpcode() == Opcode) {
257  Value *A = LHS;
258  Value *B = Op1->getOperand(0);
259  Value *C = Op1->getOperand(1);
260 
261  // Does "C op A" simplify?
262  if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
263  // It does! Return "B op V" if it simplifies or is already available.
264  // If V equals C then "B op V" is just the RHS.
265  if (V == C) return RHS;
266  // Otherwise return "B op V" if it simplifies.
267  if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
268  ++NumReassoc;
269  return W;
270  }
271  }
272  }
273 
274  return nullptr;
275 }
276 
277 /// In the case of a binary operation with a select instruction as an operand,
278 /// try to simplify the binop by seeing whether evaluating it on both branches
279 /// of the select results in the same value. Returns the common value if so,
280 /// otherwise returns null.
282  Value *RHS, const SimplifyQuery &Q,
283  unsigned MaxRecurse) {
284  // Recursion is always used, so bail out at once if we already hit the limit.
285  if (!MaxRecurse--)
286  return nullptr;
287 
288  SelectInst *SI;
289  if (isa<SelectInst>(LHS)) {
290  SI = cast<SelectInst>(LHS);
291  } else {
292  assert(isa<SelectInst>(RHS) && "No select instruction operand!");
293  SI = cast<SelectInst>(RHS);
294  }
295 
296  // Evaluate the BinOp on the true and false branches of the select.
297  Value *TV;
298  Value *FV;
299  if (SI == LHS) {
300  TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
301  FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
302  } else {
303  TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
304  FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
305  }
306 
307  // If they simplified to the same value, then return the common value.
308  // If they both failed to simplify then return null.
309  if (TV == FV)
310  return TV;
311 
312  // If one branch simplified to undef, return the other one.
313  if (TV && isa<UndefValue>(TV))
314  return FV;
315  if (FV && isa<UndefValue>(FV))
316  return TV;
317 
318  // If applying the operation did not change the true and false select values,
319  // then the result of the binop is the select itself.
320  if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
321  return SI;
322 
323  // If one branch simplified and the other did not, and the simplified
324  // value is equal to the unsimplified one, return the simplified value.
325  // For example, select (cond, X, X & Z) & Z -> X & Z.
326  if ((FV && !TV) || (TV && !FV)) {
327  // Check that the simplified value has the form "X op Y" where "op" is the
328  // same as the original operation.
329  Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
330  if (Simplified && Simplified->getOpcode() == unsigned(Opcode)) {
331  // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
332  // We already know that "op" is the same as for the simplified value. See
333  // if the operands match too. If so, return the simplified value.
334  Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
335  Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
336  Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
337  if (Simplified->getOperand(0) == UnsimplifiedLHS &&
338  Simplified->getOperand(1) == UnsimplifiedRHS)
339  return Simplified;
340  if (Simplified->isCommutative() &&
341  Simplified->getOperand(1) == UnsimplifiedLHS &&
342  Simplified->getOperand(0) == UnsimplifiedRHS)
343  return Simplified;
344  }
345  }
346 
347  return nullptr;
348 }
349 
350 /// In the case of a comparison with a select instruction, try to simplify the
351 /// comparison by seeing whether both branches of the select result in the same
352 /// value. Returns the common value if so, otherwise returns null.
354  Value *RHS, const SimplifyQuery &Q,
355  unsigned MaxRecurse) {
356  // Recursion is always used, so bail out at once if we already hit the limit.
357  if (!MaxRecurse--)
358  return nullptr;
359 
360  // Make sure the select is on the LHS.
361  if (!isa<SelectInst>(LHS)) {
362  std::swap(LHS, RHS);
363  Pred = CmpInst::getSwappedPredicate(Pred);
364  }
365  assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
366  SelectInst *SI = cast<SelectInst>(LHS);
367  Value *Cond = SI->getCondition();
368  Value *TV = SI->getTrueValue();
369  Value *FV = SI->getFalseValue();
370 
371  // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
372  // Does "cmp TV, RHS" simplify?
373  Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
374  if (TCmp == Cond) {
375  // It not only simplified, it simplified to the select condition. Replace
376  // it with 'true'.
377  TCmp = getTrue(Cond->getType());
378  } else if (!TCmp) {
379  // It didn't simplify. However if "cmp TV, RHS" is equal to the select
380  // condition then we can replace it with 'true'. Otherwise give up.
381  if (!isSameCompare(Cond, Pred, TV, RHS))
382  return nullptr;
383  TCmp = getTrue(Cond->getType());
384  }
385 
386  // Does "cmp FV, RHS" simplify?
387  Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
388  if (FCmp == Cond) {
389  // It not only simplified, it simplified to the select condition. Replace
390  // it with 'false'.
391  FCmp = getFalse(Cond->getType());
392  } else if (!FCmp) {
393  // It didn't simplify. However if "cmp FV, RHS" is equal to the select
394  // condition then we can replace it with 'false'. Otherwise give up.
395  if (!isSameCompare(Cond, Pred, FV, RHS))
396  return nullptr;
397  FCmp = getFalse(Cond->getType());
398  }
399 
400  // If both sides simplified to the same value, then use it as the result of
401  // the original comparison.
402  if (TCmp == FCmp)
403  return TCmp;
404 
405  // The remaining cases only make sense if the select condition has the same
406  // type as the result of the comparison, so bail out if this is not so.
407  if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
408  return nullptr;
409  // If the false value simplified to false, then the result of the compare
410  // is equal to "Cond && TCmp". This also catches the case when the false
411  // value simplified to false and the true value to true, returning "Cond".
412  if (match(FCmp, m_Zero()))
413  if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
414  return V;
415  // If the true value simplified to true, then the result of the compare
416  // is equal to "Cond || FCmp".
417  if (match(TCmp, m_One()))
418  if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
419  return V;
420  // Finally, if the false value simplified to true and the true value to
421  // false, then the result of the compare is equal to "!Cond".
422  if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
423  if (Value *V =
424  SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
425  Q, MaxRecurse))
426  return V;
427 
428  return nullptr;
429 }
430 
431 /// In the case of a binary operation with an operand that is a PHI instruction,
432 /// try to simplify the binop by seeing whether evaluating it on the incoming
433 /// phi values yields the same result for every value. If so returns the common
434 /// value, otherwise returns null.
436  Value *RHS, const SimplifyQuery &Q,
437  unsigned MaxRecurse) {
438  // Recursion is always used, so bail out at once if we already hit the limit.
439  if (!MaxRecurse--)
440  return nullptr;
441 
442  PHINode *PI;
443  if (isa<PHINode>(LHS)) {
444  PI = cast<PHINode>(LHS);
445  // Bail out if RHS and the phi may be mutually interdependent due to a loop.
446  if (!ValueDominatesPHI(RHS, PI, Q.DT))
447  return nullptr;
448  } else {
449  assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
450  PI = cast<PHINode>(RHS);
451  // Bail out if LHS and the phi may be mutually interdependent due to a loop.
452  if (!ValueDominatesPHI(LHS, PI, Q.DT))
453  return nullptr;
454  }
455 
456  // Evaluate the BinOp on the incoming phi values.
457  Value *CommonValue = nullptr;
458  for (Value *Incoming : PI->incoming_values()) {
459  // If the incoming value is the phi node itself, it can safely be skipped.
460  if (Incoming == PI) continue;
461  Value *V = PI == LHS ?
462  SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
463  SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
464  // If the operation failed to simplify, or simplified to a different value
465  // to previously, then give up.
466  if (!V || (CommonValue && V != CommonValue))
467  return nullptr;
468  CommonValue = V;
469  }
470 
471  return CommonValue;
472 }
473 
474 /// In the case of a comparison with a PHI instruction, try to simplify the
475 /// comparison by seeing whether comparing with all of the incoming phi values
476 /// yields the same result every time. If so returns the common result,
477 /// otherwise returns null.
479  const SimplifyQuery &Q, unsigned MaxRecurse) {
480  // Recursion is always used, so bail out at once if we already hit the limit.
481  if (!MaxRecurse--)
482  return nullptr;
483 
484  // Make sure the phi is on the LHS.
485  if (!isa<PHINode>(LHS)) {
486  std::swap(LHS, RHS);
487  Pred = CmpInst::getSwappedPredicate(Pred);
488  }
489  assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
490  PHINode *PI = cast<PHINode>(LHS);
491 
492  // Bail out if RHS and the phi may be mutually interdependent due to a loop.
493  if (!ValueDominatesPHI(RHS, PI, Q.DT))
494  return nullptr;
495 
496  // Evaluate the BinOp on the incoming phi values.
497  Value *CommonValue = nullptr;
498  for (Value *Incoming : PI->incoming_values()) {
499  // If the incoming value is the phi node itself, it can safely be skipped.
500  if (Incoming == PI) continue;
501  Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
502  // If the operation failed to simplify, or simplified to a different value
503  // to previously, then give up.
504  if (!V || (CommonValue && V != CommonValue))
505  return nullptr;
506  CommonValue = V;
507  }
508 
509  return CommonValue;
510 }
511 
513  Value *&Op0, Value *&Op1,
514  const SimplifyQuery &Q) {
515  if (auto *CLHS = dyn_cast<Constant>(Op0)) {
516  if (auto *CRHS = dyn_cast<Constant>(Op1))
517  return ConstantFoldBinaryOpOperands(Opcode, CLHS, CRHS, Q.DL);
518 
519  // Canonicalize the constant to the RHS if this is a commutative operation.
520  if (Instruction::isCommutative(Opcode))
521  std::swap(Op0, Op1);
522  }
523  return nullptr;
524 }
525 
526 /// Given operands for an Add, see if we can fold the result.
527 /// If not, this returns null.
528 static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
529  const SimplifyQuery &Q, unsigned MaxRecurse) {
530  if (Constant *C = foldOrCommuteConstant(Instruction::Add, Op0, Op1, Q))
531  return C;
532 
533  // X + undef -> undef
534  if (match(Op1, m_Undef()))
535  return Op1;
536 
537  // X + 0 -> X
538  if (match(Op1, m_Zero()))
539  return Op0;
540 
541  // X + (Y - X) -> Y
542  // (Y - X) + X -> Y
543  // Eg: X + -X -> 0
544  Value *Y = nullptr;
545  if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
546  match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
547  return Y;
548 
549  // X + ~X -> -1 since ~X = -X-1
550  Type *Ty = Op0->getType();
551  if (match(Op0, m_Not(m_Specific(Op1))) ||
552  match(Op1, m_Not(m_Specific(Op0))))
553  return Constant::getAllOnesValue(Ty);
554 
555  // add nsw/nuw (xor Y, signmask), signmask --> Y
556  // The no-wrapping add guarantees that the top bit will be set by the add.
557  // Therefore, the xor must be clearing the already set sign bit of Y.
558  if ((isNSW || isNUW) && match(Op1, m_SignMask()) &&
559  match(Op0, m_Xor(m_Value(Y), m_SignMask())))
560  return Y;
561 
562  /// i1 add -> xor.
563  if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
564  if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
565  return V;
566 
567  // Try some generic simplifications for associative operations.
568  if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
569  MaxRecurse))
570  return V;
571 
572  // Threading Add over selects and phi nodes is pointless, so don't bother.
573  // Threading over the select in "A + select(cond, B, C)" means evaluating
574  // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
575  // only if B and C are equal. If B and C are equal then (since we assume
576  // that operands have already been simplified) "select(cond, B, C)" should
577  // have been simplified to the common value of B and C already. Analysing
578  // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
579  // for threading over phi nodes.
580 
581  return nullptr;
582 }
583 
584 Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
585  const SimplifyQuery &Query) {
586  return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, Query, RecursionLimit);
587 }
588 
589 /// \brief Compute the base pointer and cumulative constant offsets for V.
590 ///
591 /// This strips all constant offsets off of V, leaving it the base pointer, and
592 /// accumulates the total constant offset applied in the returned constant. It
593 /// returns 0 if V is not a pointer, and returns the constant '0' if there are
594 /// no constant offsets applied.
595 ///
596 /// This is very similar to GetPointerBaseWithConstantOffset except it doesn't
597 /// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc.
598 /// folding.
600  bool AllowNonInbounds = false) {
602 
603  Type *IntPtrTy = DL.getIntPtrType(V->getType())->getScalarType();
604  APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());
605 
606  // Even though we don't look through PHI nodes, we could be called on an
607  // instruction in an unreachable block, which may be on a cycle.
608  SmallPtrSet<Value *, 4> Visited;
609  Visited.insert(V);
610  do {
611  if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
612  if ((!AllowNonInbounds && !GEP->isInBounds()) ||
613  !GEP->accumulateConstantOffset(DL, Offset))
614  break;
615  V = GEP->getPointerOperand();
616  } else if (Operator::getOpcode(V) == Instruction::BitCast) {
617  V = cast<Operator>(V)->getOperand(0);
618  } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
619  if (GA->isInterposable())
620  break;
621  V = GA->getAliasee();
622  } else {
623  if (auto CS = CallSite(V))
624  if (Value *RV = CS.getReturnedArgOperand()) {
625  V = RV;
626  continue;
627  }
628  break;
629  }
630  assert(V->getType()->isPtrOrPtrVectorTy() && "Unexpected operand type!");
631  } while (Visited.insert(V).second);
632 
633  Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
634  if (V->getType()->isVectorTy())
636  OffsetIntPtr);
637  return OffsetIntPtr;
638 }
639 
640 /// \brief Compute the constant difference between two pointer values.
641 /// If the difference is not a constant, returns zero.
643  Value *RHS) {
644  Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
645  Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
646 
647  // If LHS and RHS are not related via constant offsets to the same base
648  // value, there is nothing we can do here.
649  if (LHS != RHS)
650  return nullptr;
651 
652  // Otherwise, the difference of LHS - RHS can be computed as:
653  // LHS - RHS
654  // = (LHSOffset + Base) - (RHSOffset + Base)
655  // = LHSOffset - RHSOffset
656  return ConstantExpr::getSub(LHSOffset, RHSOffset);
657 }
658 
659 /// Given operands for a Sub, see if we can fold the result.
660 /// If not, this returns null.
661 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
662  const SimplifyQuery &Q, unsigned MaxRecurse) {
663  if (Constant *C = foldOrCommuteConstant(Instruction::Sub, Op0, Op1, Q))
664  return C;
665 
666  // X - undef -> undef
667  // undef - X -> undef
668  if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
669  return UndefValue::get(Op0->getType());
670 
671  // X - 0 -> X
672  if (match(Op1, m_Zero()))
673  return Op0;
674 
675  // X - X -> 0
676  if (Op0 == Op1)
677  return Constant::getNullValue(Op0->getType());
678 
679  // Is this a negation?
680  if (match(Op0, m_Zero())) {
681  // 0 - X -> 0 if the sub is NUW.
682  if (isNUW)
683  return Op0;
684 
685  KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
686  if (Known.Zero.isMaxSignedValue()) {
687  // Op1 is either 0 or the minimum signed value. If the sub is NSW, then
688  // Op1 must be 0 because negating the minimum signed value is undefined.
689  if (isNSW)
690  return Op0;
691 
692  // 0 - X -> X if X is 0 or the minimum signed value.
693  return Op1;
694  }
695  }
696 
697  // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
698  // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
699  Value *X = nullptr, *Y = nullptr, *Z = Op1;
700  if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
701  // See if "V === Y - Z" simplifies.
702  if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
703  // It does! Now see if "X + V" simplifies.
704  if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
705  // It does, we successfully reassociated!
706  ++NumReassoc;
707  return W;
708  }
709  // See if "V === X - Z" simplifies.
710  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
711  // It does! Now see if "Y + V" simplifies.
712  if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
713  // It does, we successfully reassociated!
714  ++NumReassoc;
715  return W;
716  }
717  }
718 
719  // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
720  // For example, X - (X + 1) -> -1
721  X = Op0;
722  if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
723  // See if "V === X - Y" simplifies.
724  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
725  // It does! Now see if "V - Z" simplifies.
726  if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
727  // It does, we successfully reassociated!
728  ++NumReassoc;
729  return W;
730  }
731  // See if "V === X - Z" simplifies.
732  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
733  // It does! Now see if "V - Y" simplifies.
734  if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
735  // It does, we successfully reassociated!
736  ++NumReassoc;
737  return W;
738  }
739  }
740 
741  // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
742  // For example, X - (X - Y) -> Y.
743  Z = Op0;
744  if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
745  // See if "V === Z - X" simplifies.
746  if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
747  // It does! Now see if "V + Y" simplifies.
748  if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
749  // It does, we successfully reassociated!
750  ++NumReassoc;
751  return W;
752  }
753 
754  // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
755  if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
756  match(Op1, m_Trunc(m_Value(Y))))
757  if (X->getType() == Y->getType())
758  // See if "V === X - Y" simplifies.
759  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
760  // It does! Now see if "trunc V" simplifies.
761  if (Value *W = SimplifyCastInst(Instruction::Trunc, V, Op0->getType(),
762  Q, MaxRecurse - 1))
763  // It does, return the simplified "trunc V".
764  return W;
765 
766  // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
767  if (match(Op0, m_PtrToInt(m_Value(X))) &&
768  match(Op1, m_PtrToInt(m_Value(Y))))
769  if (Constant *Result = computePointerDifference(Q.DL, X, Y))
770  return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
771 
772  // i1 sub -> xor.
773  if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
774  if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
775  return V;
776 
777  // Threading Sub over selects and phi nodes is pointless, so don't bother.
778  // Threading over the select in "A - select(cond, B, C)" means evaluating
779  // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
780  // only if B and C are equal. If B and C are equal then (since we assume
781  // that operands have already been simplified) "select(cond, B, C)" should
782  // have been simplified to the common value of B and C already. Analysing
783  // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
784  // for threading over phi nodes.
785 
786  return nullptr;
787 }
788 
789 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
790  const SimplifyQuery &Q) {
791  return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit);
792 }
793 
794 /// Given operands for a Mul, see if we can fold the result.
795 /// If not, this returns null.
796 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
797  unsigned MaxRecurse) {
798  if (Constant *C = foldOrCommuteConstant(Instruction::Mul, Op0, Op1, Q))
799  return C;
800 
801  // X * undef -> 0
802  if (match(Op1, m_Undef()))
803  return Constant::getNullValue(Op0->getType());
804 
805  // X * 0 -> 0
806  if (match(Op1, m_Zero()))
807  return Op1;
808 
809  // X * 1 -> X
810  if (match(Op1, m_One()))
811  return Op0;
812 
813  // (X / Y) * Y -> X if the division is exact.
814  Value *X = nullptr;
815  if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
816  match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
817  return X;
818 
819  // i1 mul -> and.
820  if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
821  if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
822  return V;
823 
824  // Try some generic simplifications for associative operations.
825  if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
826  MaxRecurse))
827  return V;
828 
829  // Mul distributes over Add. Try some generic simplifications based on this.
830  if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
831  Q, MaxRecurse))
832  return V;
833 
834  // If the operation is with the result of a select instruction, check whether
835  // operating on either branch of the select always yields the same value.
836  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
837  if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
838  MaxRecurse))
839  return V;
840 
841  // If the operation is with the result of a phi instruction, check whether
842  // operating on all incoming values of the phi always yields the same value.
843  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
844  if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
845  MaxRecurse))
846  return V;
847 
848  return nullptr;
849 }
850 
853 }
854 
855 /// Check for common or similar folds of integer division or integer remainder.
856 /// This applies to all 4 opcodes (sdiv/udiv/srem/urem).
857 static Value *simplifyDivRem(Value *Op0, Value *Op1, bool IsDiv) {
858  Type *Ty = Op0->getType();
859 
860  // X / undef -> undef
861  // X % undef -> undef
862  if (match(Op1, m_Undef()))
863  return Op1;
864 
865  // X / 0 -> undef
866  // X % 0 -> undef
867  // We don't need to preserve faults!
868  if (match(Op1, m_Zero()))
869  return UndefValue::get(Ty);
870 
871  // If any element of a constant divisor vector is zero, the whole op is undef.
872  auto *Op1C = dyn_cast<Constant>(Op1);
873  if (Op1C && Ty->isVectorTy()) {
874  unsigned NumElts = Ty->getVectorNumElements();
875  for (unsigned i = 0; i != NumElts; ++i) {
876  Constant *Elt = Op1C->getAggregateElement(i);
877  if (Elt && Elt->isNullValue())
878  return UndefValue::get(Ty);
879  }
880  }
881 
882  // undef / X -> 0
883  // undef % X -> 0
884  if (match(Op0, m_Undef()))
885  return Constant::getNullValue(Ty);
886 
887  // 0 / X -> 0
888  // 0 % X -> 0
889  if (match(Op0, m_Zero()))
890  return Op0;
891 
892  // X / X -> 1
893  // X % X -> 0
894  if (Op0 == Op1)
895  return IsDiv ? ConstantInt::get(Ty, 1) : Constant::getNullValue(Ty);
896 
897  // X / 1 -> X
898  // X % 1 -> 0
899  // If this is a boolean op (single-bit element type), we can't have
900  // division-by-zero or remainder-by-zero, so assume the divisor is 1.
901  if (match(Op1, m_One()) || Ty->isIntOrIntVectorTy(1))
902  return IsDiv ? Op0 : Constant::getNullValue(Ty);
903 
904  return nullptr;
905 }
906 
907 /// Given a predicate and two operands, return true if the comparison is true.
908 /// This is a helper for div/rem simplification where we return some other value
909 /// when we can prove a relationship between the operands.
910 static bool isICmpTrue(ICmpInst::Predicate Pred, Value *LHS, Value *RHS,
911  const SimplifyQuery &Q, unsigned MaxRecurse) {
912  Value *V = SimplifyICmpInst(Pred, LHS, RHS, Q, MaxRecurse);
913  Constant *C = dyn_cast_or_null<Constant>(V);
914  return (C && C->isAllOnesValue());
915 }
916 
917 /// Return true if we can simplify X / Y to 0. Remainder can adapt that answer
918 /// to simplify X % Y to X.
919 static bool isDivZero(Value *X, Value *Y, const SimplifyQuery &Q,
920  unsigned MaxRecurse, bool IsSigned) {
921  // Recursion is always used, so bail out at once if we already hit the limit.
922  if (!MaxRecurse--)
923  return false;
924 
925  if (IsSigned) {
926  // |X| / |Y| --> 0
927  //
928  // We require that 1 operand is a simple constant. That could be extended to
929  // 2 variables if we computed the sign bit for each.
930  //
931  // Make sure that a constant is not the minimum signed value because taking
932  // the abs() of that is undefined.
933  Type *Ty = X->getType();
934  const APInt *C;
935  if (match(X, m_APInt(C)) && !C->isMinSignedValue()) {
936  // Is the variable divisor magnitude always greater than the constant
937  // dividend magnitude?
938  // |Y| > |C| --> Y < -abs(C) or Y > abs(C)
939  Constant *PosDividendC = ConstantInt::get(Ty, C->abs());
940  Constant *NegDividendC = ConstantInt::get(Ty, -C->abs());
941  if (isICmpTrue(CmpInst::ICMP_SLT, Y, NegDividendC, Q, MaxRecurse) ||
942  isICmpTrue(CmpInst::ICMP_SGT, Y, PosDividendC, Q, MaxRecurse))
943  return true;
944  }
945  if (match(Y, m_APInt(C))) {
946  // Special-case: we can't take the abs() of a minimum signed value. If
947  // that's the divisor, then all we have to do is prove that the dividend
948  // is also not the minimum signed value.
949  if (C->isMinSignedValue())
950  return isICmpTrue(CmpInst::ICMP_NE, X, Y, Q, MaxRecurse);
951 
952  // Is the variable dividend magnitude always less than the constant
953  // divisor magnitude?
954  // |X| < |C| --> X > -abs(C) and X < abs(C)
955  Constant *PosDivisorC = ConstantInt::get(Ty, C->abs());
956  Constant *NegDivisorC = ConstantInt::get(Ty, -C->abs());
957  if (isICmpTrue(CmpInst::ICMP_SGT, X, NegDivisorC, Q, MaxRecurse) &&
958  isICmpTrue(CmpInst::ICMP_SLT, X, PosDivisorC, Q, MaxRecurse))
959  return true;
960  }
961  return false;
962  }
963 
964  // IsSigned == false.
965  // Is the dividend unsigned less than the divisor?
966  return isICmpTrue(ICmpInst::ICMP_ULT, X, Y, Q, MaxRecurse);
967 }
968 
969 /// These are simplifications common to SDiv and UDiv.
971  const SimplifyQuery &Q, unsigned MaxRecurse) {
972  if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
973  return C;
974 
975  if (Value *V = simplifyDivRem(Op0, Op1, true))
976  return V;
977 
978  bool IsSigned = Opcode == Instruction::SDiv;
979 
980  // (X * Y) / Y -> X if the multiplication does not overflow.
981  Value *X = nullptr, *Y = nullptr;
982  if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
983  if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
984  OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
985  // If the Mul knows it does not overflow, then we are good to go.
986  if ((IsSigned && Mul->hasNoSignedWrap()) ||
987  (!IsSigned && Mul->hasNoUnsignedWrap()))
988  return X;
989  // If X has the form X = A / Y then X * Y cannot overflow.
990  if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
991  if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
992  return X;
993  }
994 
995  // (X rem Y) / Y -> 0
996  if ((IsSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
997  (!IsSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
998  return Constant::getNullValue(Op0->getType());
999 
1000  // (X /u C1) /u C2 -> 0 if C1 * C2 overflow
1001  ConstantInt *C1, *C2;
1002  if (!IsSigned && match(Op0, m_UDiv(m_Value(X), m_ConstantInt(C1))) &&
1003  match(Op1, m_ConstantInt(C2))) {
1004  bool Overflow;
1005  (void)C1->getValue().umul_ov(C2->getValue(), Overflow);
1006  if (Overflow)
1007  return Constant::getNullValue(Op0->getType());
1008  }
1009 
1010  // If the operation is with the result of a select instruction, check whether
1011  // operating on either branch of the select always yields the same value.
1012  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1013  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1014  return V;
1015 
1016  // If the operation is with the result of a phi instruction, check whether
1017  // operating on all incoming values of the phi always yields the same value.
1018  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1019  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1020  return V;
1021 
1022  if (isDivZero(Op0, Op1, Q, MaxRecurse, IsSigned))
1023  return Constant::getNullValue(Op0->getType());
1024 
1025  return nullptr;
1026 }
1027 
1028 /// These are simplifications common to SRem and URem.
1030  const SimplifyQuery &Q, unsigned MaxRecurse) {
1031  if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1032  return C;
1033 
1034  if (Value *V = simplifyDivRem(Op0, Op1, false))
1035  return V;
1036 
1037  // (X % Y) % Y -> X % Y
1038  if ((Opcode == Instruction::SRem &&
1039  match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1040  (Opcode == Instruction::URem &&
1041  match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1042  return Op0;
1043 
1044  // If the operation is with the result of a select instruction, check whether
1045  // operating on either branch of the select always yields the same value.
1046  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1047  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1048  return V;
1049 
1050  // If the operation is with the result of a phi instruction, check whether
1051  // operating on all incoming values of the phi always yields the same value.
1052  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1053  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1054  return V;
1055 
1056  // If X / Y == 0, then X % Y == X.
1057  if (isDivZero(Op0, Op1, Q, MaxRecurse, Opcode == Instruction::SRem))
1058  return Op0;
1059 
1060  return nullptr;
1061 }
1062 
1063 /// Given operands for an SDiv, see if we can fold the result.
1064 /// If not, this returns null.
1065 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1066  unsigned MaxRecurse) {
1067  return simplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse);
1068 }
1069 
1072 }
1073 
1074 /// Given operands for a UDiv, see if we can fold the result.
1075 /// If not, this returns null.
1076 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1077  unsigned MaxRecurse) {
1078  return simplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse);
1079 }
1080 
1083 }
1084 
1085 /// Given operands for an SRem, see if we can fold the result.
1086 /// If not, this returns null.
1087 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1088  unsigned MaxRecurse) {
1089  return simplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse);
1090 }
1091 
1094 }
1095 
1096 /// Given operands for a URem, see if we can fold the result.
1097 /// If not, this returns null.
1098 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1099  unsigned MaxRecurse) {
1100  return simplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse);
1101 }
1102 
1105 }
1106 
1107 /// Returns true if a shift by \c Amount always yields undef.
1108 static bool isUndefShift(Value *Amount) {
1109  Constant *C = dyn_cast<Constant>(Amount);
1110  if (!C)
1111  return false;
1112 
1113  // X shift by undef -> undef because it may shift by the bitwidth.
1114  if (isa<UndefValue>(C))
1115  return true;
1116 
1117  // Shifting by the bitwidth or more is undefined.
1118  if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
1119  if (CI->getValue().getLimitedValue() >=
1120  CI->getType()->getScalarSizeInBits())
1121  return true;
1122 
1123  // If all lanes of a vector shift are undefined the whole shift is.
1124  if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) {
1125  for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I)
1127  return false;
1128  return true;
1129  }
1130 
1131  return false;
1132 }
1133 
1134 /// Given operands for an Shl, LShr or AShr, see if we can fold the result.
1135 /// If not, this returns null.
1137  Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse) {
1138  if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1139  return C;
1140 
1141  // 0 shift by X -> 0
1142  if (match(Op0, m_Zero()))
1143  return Op0;
1144 
1145  // X shift by 0 -> X
1146  if (match(Op1, m_Zero()))
1147  return Op0;
1148 
1149  // Fold undefined shifts.
1150  if (isUndefShift(Op1))
1151  return UndefValue::get(Op0->getType());
1152 
1153  // If the operation is with the result of a select instruction, check whether
1154  // operating on either branch of the select always yields the same value.
1155  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1156  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1157  return V;
1158 
1159  // If the operation is with the result of a phi instruction, check whether
1160  // operating on all incoming values of the phi always yields the same value.
1161  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1162  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1163  return V;
1164 
1165  // If any bits in the shift amount make that value greater than or equal to
1166  // the number of bits in the type, the shift is undefined.
1167  KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1168  if (Known.One.getLimitedValue() >= Known.getBitWidth())
1169  return UndefValue::get(Op0->getType());
1170 
1171  // If all valid bits in the shift amount are known zero, the first operand is
1172  // unchanged.
1173  unsigned NumValidShiftBits = Log2_32_Ceil(Known.getBitWidth());
1174  if (Known.countMinTrailingZeros() >= NumValidShiftBits)
1175  return Op0;
1176 
1177  return nullptr;
1178 }
1179 
1180 /// \brief Given operands for an Shl, LShr or AShr, see if we can
1181 /// fold the result. If not, this returns null.
1183  Value *Op1, bool isExact, const SimplifyQuery &Q,
1184  unsigned MaxRecurse) {
1185  if (Value *V = SimplifyShift(Opcode, Op0, Op1, Q, MaxRecurse))
1186  return V;
1187 
1188  // X >> X -> 0
1189  if (Op0 == Op1)
1190  return Constant::getNullValue(Op0->getType());
1191 
1192  // undef >> X -> 0
1193  // undef >> X -> undef (if it's exact)
1194  if (match(Op0, m_Undef()))
1195  return isExact ? Op0 : Constant::getNullValue(Op0->getType());
1196 
1197  // The low bit cannot be shifted out of an exact shift if it is set.
1198  if (isExact) {
1199  KnownBits Op0Known = computeKnownBits(Op0, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT);
1200  if (Op0Known.One[0])
1201  return Op0;
1202  }
1203 
1204  return nullptr;
1205 }
1206 
1207 /// Given operands for an Shl, see if we can fold the result.
1208 /// If not, this returns null.
1209 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1210  const SimplifyQuery &Q, unsigned MaxRecurse) {
1211  if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1212  return V;
1213 
1214  // undef << X -> 0
1215  // undef << X -> undef if (if it's NSW/NUW)
1216  if (match(Op0, m_Undef()))
1217  return isNSW || isNUW ? Op0 : Constant::getNullValue(Op0->getType());
1218 
1219  // (X >> A) << A -> X
1220  Value *X;
1221  if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1222  return X;
1223  return nullptr;
1224 }
1225 
1226 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1227  const SimplifyQuery &Q) {
1228  return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit);
1229 }
1230 
1231 /// Given operands for an LShr, see if we can fold the result.
1232 /// If not, this returns null.
1233 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1234  const SimplifyQuery &Q, unsigned MaxRecurse) {
1235  if (Value *V = SimplifyRightShift(Instruction::LShr, Op0, Op1, isExact, Q,
1236  MaxRecurse))
1237  return V;
1238 
1239  // (X << A) >> A -> X
1240  Value *X;
1241  if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1))))
1242  return X;
1243 
1244  return nullptr;
1245 }
1246 
1247 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1248  const SimplifyQuery &Q) {
1249  return ::SimplifyLShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1250 }
1251 
1252 /// Given operands for an AShr, see if we can fold the result.
1253 /// If not, this returns null.
1254 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1255  const SimplifyQuery &Q, unsigned MaxRecurse) {
1256  if (Value *V = SimplifyRightShift(Instruction::AShr, Op0, Op1, isExact, Q,
1257  MaxRecurse))
1258  return V;
1259 
1260  // all ones >>a X -> all ones
1261  if (match(Op0, m_AllOnes()))
1262  return Op0;
1263 
1264  // (X << A) >> A -> X
1265  Value *X;
1266  if (match(Op0, m_NSWShl(m_Value(X), m_Specific(Op1))))
1267  return X;
1268 
1269  // Arithmetic shifting an all-sign-bit value is a no-op.
1270  unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1271  if (NumSignBits == Op0->getType()->getScalarSizeInBits())
1272  return Op0;
1273 
1274  return nullptr;
1275 }
1276 
1277 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1278  const SimplifyQuery &Q) {
1279  return ::SimplifyAShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1280 }
1281 
1282 /// Commuted variants are assumed to be handled by calling this function again
1283 /// with the parameters swapped.
1285  ICmpInst *UnsignedICmp, bool IsAnd) {
1286  Value *X, *Y;
1287 
1288  ICmpInst::Predicate EqPred;
1289  if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) ||
1290  !ICmpInst::isEquality(EqPred))
1291  return nullptr;
1292 
1293  ICmpInst::Predicate UnsignedPred;
1294  if (match(UnsignedICmp, m_ICmp(UnsignedPred, m_Value(X), m_Specific(Y))) &&
1295  ICmpInst::isUnsigned(UnsignedPred))
1296  ;
1297  else if (match(UnsignedICmp,
1298  m_ICmp(UnsignedPred, m_Value(Y), m_Specific(X))) &&
1299  ICmpInst::isUnsigned(UnsignedPred))
1300  UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred);
1301  else
1302  return nullptr;
1303 
1304  // X < Y && Y != 0 --> X < Y
1305  // X < Y || Y != 0 --> Y != 0
1306  if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE)
1307  return IsAnd ? UnsignedICmp : ZeroICmp;
1308 
1309  // X >= Y || Y != 0 --> true
1310  // X >= Y || Y == 0 --> X >= Y
1311  if (UnsignedPred == ICmpInst::ICMP_UGE && !IsAnd) {
1312  if (EqPred == ICmpInst::ICMP_NE)
1313  return getTrue(UnsignedICmp->getType());
1314  return UnsignedICmp;
1315  }
1316 
1317  // X < Y && Y == 0 --> false
1318  if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
1319  IsAnd)
1320  return getFalse(UnsignedICmp->getType());
1321 
1322  return nullptr;
1323 }
1324 
1325 /// Commuted variants are assumed to be handled by calling this function again
1326 /// with the parameters swapped.
1328  ICmpInst::Predicate Pred0, Pred1;
1329  Value *A ,*B;
1330  if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
1331  !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
1332  return nullptr;
1333 
1334  // We have (icmp Pred0, A, B) & (icmp Pred1, A, B).
1335  // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1336  // can eliminate Op1 from this 'and'.
1337  if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
1338  return Op0;
1339 
1340  // Check for any combination of predicates that are guaranteed to be disjoint.
1341  if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
1342  (Pred0 == ICmpInst::ICMP_EQ && ICmpInst::isFalseWhenEqual(Pred1)) ||
1343  (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT) ||
1344  (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT))
1345  return getFalse(Op0->getType());
1346 
1347  return nullptr;
1348 }
1349 
1350 /// Commuted variants are assumed to be handled by calling this function again
1351 /// with the parameters swapped.
1353  ICmpInst::Predicate Pred0, Pred1;
1354  Value *A ,*B;
1355  if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
1356  !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
1357  return nullptr;
1358 
1359  // We have (icmp Pred0, A, B) | (icmp Pred1, A, B).
1360  // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1361  // can eliminate Op0 from this 'or'.
1362  if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
1363  return Op1;
1364 
1365  // Check for any combination of predicates that cover the entire range of
1366  // possibilities.
1367  if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
1368  (Pred0 == ICmpInst::ICMP_NE && ICmpInst::isTrueWhenEqual(Pred1)) ||
1369  (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGE) ||
1370  (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGE))
1371  return getTrue(Op0->getType());
1372 
1373  return nullptr;
1374 }
1375 
1376 /// Test if a pair of compares with a shared operand and 2 constants has an
1377 /// empty set intersection, full set union, or if one compare is a superset of
1378 /// the other.
1380  bool IsAnd) {
1381  // Look for this pattern: {and/or} (icmp X, C0), (icmp X, C1)).
1382  if (Cmp0->getOperand(0) != Cmp1->getOperand(0))
1383  return nullptr;
1384 
1385  const APInt *C0, *C1;
1386  if (!match(Cmp0->getOperand(1), m_APInt(C0)) ||
1387  !match(Cmp1->getOperand(1), m_APInt(C1)))
1388  return nullptr;
1389 
1390  auto Range0 = ConstantRange::makeExactICmpRegion(Cmp0->getPredicate(), *C0);
1391  auto Range1 = ConstantRange::makeExactICmpRegion(Cmp1->getPredicate(), *C1);
1392 
1393  // For and-of-compares, check if the intersection is empty:
1394  // (icmp X, C0) && (icmp X, C1) --> empty set --> false
1395  if (IsAnd && Range0.intersectWith(Range1).isEmptySet())
1396  return getFalse(Cmp0->getType());
1397 
1398  // For or-of-compares, check if the union is full:
1399  // (icmp X, C0) || (icmp X, C1) --> full set --> true
1400  if (!IsAnd && Range0.unionWith(Range1).isFullSet())
1401  return getTrue(Cmp0->getType());
1402 
1403  // Is one range a superset of the other?
1404  // If this is and-of-compares, take the smaller set:
1405  // (icmp sgt X, 4) && (icmp sgt X, 42) --> icmp sgt X, 42
1406  // If this is or-of-compares, take the larger set:
1407  // (icmp sgt X, 4) || (icmp sgt X, 42) --> icmp sgt X, 4
1408  if (Range0.contains(Range1))
1409  return IsAnd ? Cmp1 : Cmp0;
1410  if (Range1.contains(Range0))
1411  return IsAnd ? Cmp0 : Cmp1;
1412 
1413  return nullptr;
1414 }
1415 
1417  // (icmp (add V, C0), C1) & (icmp V, C0)
1418  ICmpInst::Predicate Pred0, Pred1;
1419  const APInt *C0, *C1;
1420  Value *V;
1421  if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
1422  return nullptr;
1423 
1424  if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
1425  return nullptr;
1426 
1427  auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1428  if (AddInst->getOperand(1) != Op1->getOperand(1))
1429  return nullptr;
1430 
1431  Type *ITy = Op0->getType();
1432  bool isNSW = AddInst->hasNoSignedWrap();
1433  bool isNUW = AddInst->hasNoUnsignedWrap();
1434 
1435  const APInt Delta = *C1 - *C0;
1436  if (C0->isStrictlyPositive()) {
1437  if (Delta == 2) {
1438  if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
1439  return getFalse(ITy);
1440  if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1441  return getFalse(ITy);
1442  }
1443  if (Delta == 1) {
1444  if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
1445  return getFalse(ITy);
1446  if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1447  return getFalse(ITy);
1448  }
1449  }
1450  if (C0->getBoolValue() && isNUW) {
1451  if (Delta == 2)
1452  if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
1453  return getFalse(ITy);
1454  if (Delta == 1)
1455  if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
1456  return getFalse(ITy);
1457  }
1458 
1459  return nullptr;
1460 }
1461 
1463  if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/true))
1464  return X;
1465  if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/true))
1466  return X;
1467 
1468  if (Value *X = simplifyAndOfICmpsWithSameOperands(Op0, Op1))
1469  return X;
1470  if (Value *X = simplifyAndOfICmpsWithSameOperands(Op1, Op0))
1471  return X;
1472 
1473  if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, true))
1474  return X;
1475 
1476  if (Value *X = simplifyAndOfICmpsWithAdd(Op0, Op1))
1477  return X;
1478  if (Value *X = simplifyAndOfICmpsWithAdd(Op1, Op0))
1479  return X;
1480 
1481  return nullptr;
1482 }
1483 
1485  // (icmp (add V, C0), C1) | (icmp V, C0)
1486  ICmpInst::Predicate Pred0, Pred1;
1487  const APInt *C0, *C1;
1488  Value *V;
1489  if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
1490  return nullptr;
1491 
1492  if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
1493  return nullptr;
1494 
1495  auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1496  if (AddInst->getOperand(1) != Op1->getOperand(1))
1497  return nullptr;
1498 
1499  Type *ITy = Op0->getType();
1500  bool isNSW = AddInst->hasNoSignedWrap();
1501  bool isNUW = AddInst->hasNoUnsignedWrap();
1502 
1503  const APInt Delta = *C1 - *C0;
1504  if (C0->isStrictlyPositive()) {
1505  if (Delta == 2) {
1506  if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE)
1507  return getTrue(ITy);
1508  if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1509  return getTrue(ITy);
1510  }
1511  if (Delta == 1) {
1512  if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE)
1513  return getTrue(ITy);
1514  if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1515  return getTrue(ITy);
1516  }
1517  }
1518  if (C0->getBoolValue() && isNUW) {
1519  if (Delta == 2)
1520  if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE)
1521  return getTrue(ITy);
1522  if (Delta == 1)
1523  if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE)
1524  return getTrue(ITy);
1525  }
1526 
1527  return nullptr;
1528 }
1529 
1531  if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/false))
1532  return X;
1533  if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/false))
1534  return X;
1535 
1536  if (Value *X = simplifyOrOfICmpsWithSameOperands(Op0, Op1))
1537  return X;
1538  if (Value *X = simplifyOrOfICmpsWithSameOperands(Op1, Op0))
1539  return X;
1540 
1541  if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, false))
1542  return X;
1543 
1544  if (Value *X = simplifyOrOfICmpsWithAdd(Op0, Op1))
1545  return X;
1546  if (Value *X = simplifyOrOfICmpsWithAdd(Op1, Op0))
1547  return X;
1548 
1549  return nullptr;
1550 }
1551 
1552 static Value *simplifyAndOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS, bool IsAnd) {
1553  Value *LHS0 = LHS->getOperand(0), *LHS1 = LHS->getOperand(1);
1554  Value *RHS0 = RHS->getOperand(0), *RHS1 = RHS->getOperand(1);
1555  if (LHS0->getType() != RHS0->getType())
1556  return nullptr;
1557 
1558  FCmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
1559  if ((PredL == FCmpInst::FCMP_ORD && PredR == FCmpInst::FCMP_ORD && IsAnd) ||
1560  (PredL == FCmpInst::FCMP_UNO && PredR == FCmpInst::FCMP_UNO && !IsAnd)) {
1561  // (fcmp ord NNAN, X) & (fcmp ord X, Y) --> fcmp ord X, Y
1562  // (fcmp ord NNAN, X) & (fcmp ord Y, X) --> fcmp ord Y, X
1563  // (fcmp ord X, NNAN) & (fcmp ord X, Y) --> fcmp ord X, Y
1564  // (fcmp ord X, NNAN) & (fcmp ord Y, X) --> fcmp ord Y, X
1565  // (fcmp uno NNAN, X) | (fcmp uno X, Y) --> fcmp uno X, Y
1566  // (fcmp uno NNAN, X) | (fcmp uno Y, X) --> fcmp uno Y, X
1567  // (fcmp uno X, NNAN) | (fcmp uno X, Y) --> fcmp uno X, Y
1568  // (fcmp uno X, NNAN) | (fcmp uno Y, X) --> fcmp uno Y, X
1569  if ((isKnownNeverNaN(LHS0) && (LHS1 == RHS0 || LHS1 == RHS1)) ||
1570  (isKnownNeverNaN(LHS1) && (LHS0 == RHS0 || LHS0 == RHS1)))
1571  return RHS;
1572 
1573  // (fcmp ord X, Y) & (fcmp ord NNAN, X) --> fcmp ord X, Y
1574  // (fcmp ord Y, X) & (fcmp ord NNAN, X) --> fcmp ord Y, X
1575  // (fcmp ord X, Y) & (fcmp ord X, NNAN) --> fcmp ord X, Y
1576  // (fcmp ord Y, X) & (fcmp ord X, NNAN) --> fcmp ord Y, X
1577  // (fcmp uno X, Y) | (fcmp uno NNAN, X) --> fcmp uno X, Y
1578  // (fcmp uno Y, X) | (fcmp uno NNAN, X) --> fcmp uno Y, X
1579  // (fcmp uno X, Y) | (fcmp uno X, NNAN) --> fcmp uno X, Y
1580  // (fcmp uno Y, X) | (fcmp uno X, NNAN) --> fcmp uno Y, X
1581  if ((isKnownNeverNaN(RHS0) && (RHS1 == LHS0 || RHS1 == LHS1)) ||
1582  (isKnownNeverNaN(RHS1) && (RHS0 == LHS0 || RHS0 == LHS1)))
1583  return LHS;
1584  }
1585 
1586  return nullptr;
1587 }
1588 
1589 static Value *simplifyAndOrOfCmps(Value *Op0, Value *Op1, bool IsAnd) {
1590  // Look through casts of the 'and' operands to find compares.
1591  auto *Cast0 = dyn_cast<CastInst>(Op0);
1592  auto *Cast1 = dyn_cast<CastInst>(Op1);
1593  if (Cast0 && Cast1 && Cast0->getOpcode() == Cast1->getOpcode() &&
1594  Cast0->getSrcTy() == Cast1->getSrcTy()) {
1595  Op0 = Cast0->getOperand(0);
1596  Op1 = Cast1->getOperand(0);
1597  }
1598 
1599  Value *V = nullptr;
1600  auto *ICmp0 = dyn_cast<ICmpInst>(Op0);
1601  auto *ICmp1 = dyn_cast<ICmpInst>(Op1);
1602  if (ICmp0 && ICmp1)
1603  V = IsAnd ? simplifyAndOfICmps(ICmp0, ICmp1) :
1604  simplifyOrOfICmps(ICmp0, ICmp1);
1605 
1606  auto *FCmp0 = dyn_cast<FCmpInst>(Op0);
1607  auto *FCmp1 = dyn_cast<FCmpInst>(Op1);
1608  if (FCmp0 && FCmp1)
1609  V = simplifyAndOrOfFCmps(FCmp0, FCmp1, IsAnd);
1610 
1611  if (!V)
1612  return nullptr;
1613  if (!Cast0)
1614  return V;
1615 
1616  // If we looked through casts, we can only handle a constant simplification
1617  // because we are not allowed to create a cast instruction here.
1618  if (auto *C = dyn_cast<Constant>(V))
1619  return ConstantExpr::getCast(Cast0->getOpcode(), C, Cast0->getType());
1620 
1621  return nullptr;
1622 }
1623 
1624 /// Given operands for an And, see if we can fold the result.
1625 /// If not, this returns null.
1626 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1627  unsigned MaxRecurse) {
1628  if (Constant *C = foldOrCommuteConstant(Instruction::And, Op0, Op1, Q))
1629  return C;
1630 
1631  // X & undef -> 0
1632  if (match(Op1, m_Undef()))
1633  return Constant::getNullValue(Op0->getType());
1634 
1635  // X & X = X
1636  if (Op0 == Op1)
1637  return Op0;
1638 
1639  // X & 0 = 0
1640  if (match(Op1, m_Zero()))
1641  return Op1;
1642 
1643  // X & -1 = X
1644  if (match(Op1, m_AllOnes()))
1645  return Op0;
1646 
1647  // A & ~A = ~A & A = 0
1648  if (match(Op0, m_Not(m_Specific(Op1))) ||
1649  match(Op1, m_Not(m_Specific(Op0))))
1650  return Constant::getNullValue(Op0->getType());
1651 
1652  // (A | ?) & A = A
1653  if (match(Op0, m_c_Or(m_Specific(Op1), m_Value())))
1654  return Op1;
1655 
1656  // A & (A | ?) = A
1657  if (match(Op1, m_c_Or(m_Specific(Op0), m_Value())))
1658  return Op0;
1659 
1660  // A mask that only clears known zeros of a shifted value is a no-op.
1661  Value *X;
1662  const APInt *Mask;
1663  const APInt *ShAmt;
1664  if (match(Op1, m_APInt(Mask))) {
1665  // If all bits in the inverted and shifted mask are clear:
1666  // and (shl X, ShAmt), Mask --> shl X, ShAmt
1667  if (match(Op0, m_Shl(m_Value(X), m_APInt(ShAmt))) &&
1668  (~(*Mask)).lshr(*ShAmt).isNullValue())
1669  return Op0;
1670 
1671  // If all bits in the inverted and shifted mask are clear:
1672  // and (lshr X, ShAmt), Mask --> lshr X, ShAmt
1673  if (match(Op0, m_LShr(m_Value(X), m_APInt(ShAmt))) &&
1674  (~(*Mask)).shl(*ShAmt).isNullValue())
1675  return Op0;
1676  }
1677 
1678  // A & (-A) = A if A is a power of two or zero.
1679  if (match(Op0, m_Neg(m_Specific(Op1))) ||
1680  match(Op1, m_Neg(m_Specific(Op0)))) {
1681  if (isKnownToBeAPowerOfTwo(Op0, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1682  Q.DT))
1683  return Op0;
1684  if (isKnownToBeAPowerOfTwo(Op1, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1685  Q.DT))
1686  return Op1;
1687  }
1688 
1689  if (Value *V = simplifyAndOrOfCmps(Op0, Op1, true))
1690  return V;
1691 
1692  // Try some generic simplifications for associative operations.
1693  if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1694  MaxRecurse))
1695  return V;
1696 
1697  // And distributes over Or. Try some generic simplifications based on this.
1698  if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1699  Q, MaxRecurse))
1700  return V;
1701 
1702  // And distributes over Xor. Try some generic simplifications based on this.
1703  if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1704  Q, MaxRecurse))
1705  return V;
1706 
1707  // If the operation is with the result of a select instruction, check whether
1708  // operating on either branch of the select always yields the same value.
1709  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1710  if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1711  MaxRecurse))
1712  return V;
1713 
1714  // If the operation is with the result of a phi instruction, check whether
1715  // operating on all incoming values of the phi always yields the same value.
1716  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1717  if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1718  MaxRecurse))
1719  return V;
1720 
1721  return nullptr;
1722 }
1723 
1726 }
1727 
1728 /// Given operands for an Or, see if we can fold the result.
1729 /// If not, this returns null.
1730 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1731  unsigned MaxRecurse) {
1732  if (Constant *C = foldOrCommuteConstant(Instruction::Or, Op0, Op1, Q))
1733  return C;
1734 
1735  // X | undef -> -1
1736  if (match(Op1, m_Undef()))
1737  return Constant::getAllOnesValue(Op0->getType());
1738 
1739  // X | X = X
1740  if (Op0 == Op1)
1741  return Op0;
1742 
1743  // X | 0 = X
1744  if (match(Op1, m_Zero()))
1745  return Op0;
1746 
1747  // X | -1 = -1
1748  if (match(Op1, m_AllOnes()))
1749  return Op1;
1750 
1751  // A | ~A = ~A | A = -1
1752  if (match(Op0, m_Not(m_Specific(Op1))) ||
1753  match(Op1, m_Not(m_Specific(Op0))))
1754  return Constant::getAllOnesValue(Op0->getType());
1755 
1756  // (A & ?) | A = A
1757  if (match(Op0, m_c_And(m_Specific(Op1), m_Value())))
1758  return Op1;
1759 
1760  // A | (A & ?) = A
1761  if (match(Op1, m_c_And(m_Specific(Op0), m_Value())))
1762  return Op0;
1763 
1764  // ~(A & ?) | A = -1
1765  if (match(Op0, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
1766  return Constant::getAllOnesValue(Op1->getType());
1767 
1768  // A | ~(A & ?) = -1
1769  if (match(Op1, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
1770  return Constant::getAllOnesValue(Op0->getType());
1771 
1772  Value *A, *B;
1773  // (A & ~B) | (A ^ B) -> (A ^ B)
1774  // (~B & A) | (A ^ B) -> (A ^ B)
1775  // (A & ~B) | (B ^ A) -> (B ^ A)
1776  // (~B & A) | (B ^ A) -> (B ^ A)
1777  if (match(Op1, m_Xor(m_Value(A), m_Value(B))) &&
1778  (match(Op0, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
1779  match(Op0, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
1780  return Op1;
1781 
1782  // Commute the 'or' operands.
1783  // (A ^ B) | (A & ~B) -> (A ^ B)
1784  // (A ^ B) | (~B & A) -> (A ^ B)
1785  // (B ^ A) | (A & ~B) -> (B ^ A)
1786  // (B ^ A) | (~B & A) -> (B ^ A)
1787  if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
1788  (match(Op1, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
1789  match(Op1, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
1790  return Op0;
1791 
1792  // (A & B) | (~A ^ B) -> (~A ^ B)
1793  // (B & A) | (~A ^ B) -> (~A ^ B)
1794  // (A & B) | (B ^ ~A) -> (B ^ ~A)
1795  // (B & A) | (B ^ ~A) -> (B ^ ~A)
1796  if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1797  (match(Op1, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
1798  match(Op1, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
1799  return Op1;
1800 
1801  // (~A ^ B) | (A & B) -> (~A ^ B)
1802  // (~A ^ B) | (B & A) -> (~A ^ B)
1803  // (B ^ ~A) | (A & B) -> (B ^ ~A)
1804  // (B ^ ~A) | (B & A) -> (B ^ ~A)
1805  if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1806  (match(Op0, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
1807  match(Op0, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
1808  return Op0;
1809 
1810  if (Value *V = simplifyAndOrOfCmps(Op0, Op1, false))
1811  return V;
1812 
1813  // Try some generic simplifications for associative operations.
1814  if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1815  MaxRecurse))
1816  return V;
1817 
1818  // Or distributes over And. Try some generic simplifications based on this.
1819  if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1820  MaxRecurse))
1821  return V;
1822 
1823  // If the operation is with the result of a select instruction, check whether
1824  // operating on either branch of the select always yields the same value.
1825  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1826  if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1827  MaxRecurse))
1828  return V;
1829 
1830  // (A & C1)|(B & C2)
1831  const APInt *C1, *C2;
1832  if (match(Op0, m_And(m_Value(A), m_APInt(C1))) &&
1833  match(Op1, m_And(m_Value(B), m_APInt(C2)))) {
1834  if (*C1 == ~*C2) {
1835  // (A & C1)|(B & C2)
1836  // If we have: ((V + N) & C1) | (V & C2)
1837  // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
1838  // replace with V+N.
1839  Value *N;
1840  if (C2->isMask() && // C2 == 0+1+
1841  match(A, m_c_Add(m_Specific(B), m_Value(N)))) {
1842  // Add commutes, try both ways.
1843  if (MaskedValueIsZero(N, *C2, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1844  return A;
1845  }
1846  // Or commutes, try both ways.
1847  if (C1->isMask() &&
1848  match(B, m_c_Add(m_Specific(A), m_Value(N)))) {
1849  // Add commutes, try both ways.
1850  if (MaskedValueIsZero(N, *C1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1851  return B;
1852  }
1853  }
1854  }
1855 
1856  // If the operation is with the result of a phi instruction, check whether
1857  // operating on all incoming values of the phi always yields the same value.
1858  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1859  if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1860  return V;
1861 
1862  return nullptr;
1863 }
1864 
1867 }
1868 
1869 /// Given operands for a Xor, see if we can fold the result.
1870 /// If not, this returns null.
1871 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1872  unsigned MaxRecurse) {
1873  if (Constant *C = foldOrCommuteConstant(Instruction::Xor, Op0, Op1, Q))
1874  return C;
1875 
1876  // A ^ undef -> undef
1877  if (match(Op1, m_Undef()))
1878  return Op1;
1879 
1880  // A ^ 0 = A
1881  if (match(Op1, m_Zero()))
1882  return Op0;
1883 
1884  // A ^ A = 0
1885  if (Op0 == Op1)
1886  return Constant::getNullValue(Op0->getType());
1887 
1888  // A ^ ~A = ~A ^ A = -1
1889  if (match(Op0, m_Not(m_Specific(Op1))) ||
1890  match(Op1, m_Not(m_Specific(Op0))))
1891  return Constant::getAllOnesValue(Op0->getType());
1892 
1893  // Try some generic simplifications for associative operations.
1894  if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1895  MaxRecurse))
1896  return V;
1897 
1898  // Threading Xor over selects and phi nodes is pointless, so don't bother.
1899  // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1900  // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1901  // only if B and C are equal. If B and C are equal then (since we assume
1902  // that operands have already been simplified) "select(cond, B, C)" should
1903  // have been simplified to the common value of B and C already. Analysing
1904  // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1905  // for threading over phi nodes.
1906 
1907  return nullptr;
1908 }
1909 
1912 }
1913 
1914 
1916  return CmpInst::makeCmpResultType(Op->getType());
1917 }
1918 
1919 /// Rummage around inside V looking for something equivalent to the comparison
1920 /// "LHS Pred RHS". Return such a value if found, otherwise return null.
1921 /// Helper function for analyzing max/min idioms.
1923  Value *LHS, Value *RHS) {
1925  if (!SI)
1926  return nullptr;
1927  CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1928  if (!Cmp)
1929  return nullptr;
1930  Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1931  if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1932  return Cmp;
1933  if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1934  LHS == CmpRHS && RHS == CmpLHS)
1935  return Cmp;
1936  return nullptr;
1937 }
1938 
1939 // A significant optimization not implemented here is assuming that alloca
1940 // addresses are not equal to incoming argument values. They don't *alias*,
1941 // as we say, but that doesn't mean they aren't equal, so we take a
1942 // conservative approach.
1943 //
1944 // This is inspired in part by C++11 5.10p1:
1945 // "Two pointers of the same type compare equal if and only if they are both
1946 // null, both point to the same function, or both represent the same
1947 // address."
1948 //
1949 // This is pretty permissive.
1950 //
1951 // It's also partly due to C11 6.5.9p6:
1952 // "Two pointers compare equal if and only if both are null pointers, both are
1953 // pointers to the same object (including a pointer to an object and a
1954 // subobject at its beginning) or function, both are pointers to one past the
1955 // last element of the same array object, or one is a pointer to one past the
1956 // end of one array object and the other is a pointer to the start of a
1957 // different array object that happens to immediately follow the first array
1958 // object in the address space.)
1959 //
1960 // C11's version is more restrictive, however there's no reason why an argument
1961 // couldn't be a one-past-the-end value for a stack object in the caller and be
1962 // equal to the beginning of a stack object in the callee.
1963 //
1964 // If the C and C++ standards are ever made sufficiently restrictive in this
1965 // area, it may be possible to update LLVM's semantics accordingly and reinstate
1966 // this optimization.
1967 static Constant *
1969  const DominatorTree *DT, CmpInst::Predicate Pred,
1970  AssumptionCache *AC, const Instruction *CxtI,
1971  Value *LHS, Value *RHS) {
1972  // First, skip past any trivial no-ops.
1973  LHS = LHS->stripPointerCasts();
1974  RHS = RHS->stripPointerCasts();
1975 
1976  // A non-null pointer is not equal to a null pointer.
1977  if (llvm::isKnownNonZero(LHS, DL) && isa<ConstantPointerNull>(RHS) &&
1978  (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
1979  return ConstantInt::get(GetCompareTy(LHS),
1980  !CmpInst::isTrueWhenEqual(Pred));
1981 
1982  // We can only fold certain predicates on pointer comparisons.
1983  switch (Pred) {
1984  default:
1985  return nullptr;
1986 
1987  // Equality comaprisons are easy to fold.
1988  case CmpInst::ICMP_EQ:
1989  case CmpInst::ICMP_NE:
1990  break;
1991 
1992  // We can only handle unsigned relational comparisons because 'inbounds' on
1993  // a GEP only protects against unsigned wrapping.
1994  case CmpInst::ICMP_UGT:
1995  case CmpInst::ICMP_UGE:
1996  case CmpInst::ICMP_ULT:
1997  case CmpInst::ICMP_ULE:
1998  // However, we have to switch them to their signed variants to handle
1999  // negative indices from the base pointer.
2000  Pred = ICmpInst::getSignedPredicate(Pred);
2001  break;
2002  }
2003 
2004  // Strip off any constant offsets so that we can reason about them.
2005  // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
2006  // here and compare base addresses like AliasAnalysis does, however there are
2007  // numerous hazards. AliasAnalysis and its utilities rely on special rules
2008  // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
2009  // doesn't need to guarantee pointer inequality when it says NoAlias.
2010  Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
2011  Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
2012 
2013  // If LHS and RHS are related via constant offsets to the same base
2014  // value, we can replace it with an icmp which just compares the offsets.
2015  if (LHS == RHS)
2016  return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
2017 
2018  // Various optimizations for (in)equality comparisons.
2019  if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
2020  // Different non-empty allocations that exist at the same time have
2021  // different addresses (if the program can tell). Global variables always
2022  // exist, so they always exist during the lifetime of each other and all
2023  // allocas. Two different allocas usually have different addresses...
2024  //
2025  // However, if there's an @llvm.stackrestore dynamically in between two
2026  // allocas, they may have the same address. It's tempting to reduce the
2027  // scope of the problem by only looking at *static* allocas here. That would
2028  // cover the majority of allocas while significantly reducing the likelihood
2029  // of having an @llvm.stackrestore pop up in the middle. However, it's not
2030  // actually impossible for an @llvm.stackrestore to pop up in the middle of
2031  // an entry block. Also, if we have a block that's not attached to a
2032  // function, we can't tell if it's "static" under the current definition.
2033  // Theoretically, this problem could be fixed by creating a new kind of
2034  // instruction kind specifically for static allocas. Such a new instruction
2035  // could be required to be at the top of the entry block, thus preventing it
2036  // from being subject to a @llvm.stackrestore. Instcombine could even
2037  // convert regular allocas into these special allocas. It'd be nifty.
2038  // However, until then, this problem remains open.
2039  //
2040  // So, we'll assume that two non-empty allocas have different addresses
2041  // for now.
2042  //
2043  // With all that, if the offsets are within the bounds of their allocations
2044  // (and not one-past-the-end! so we can't use inbounds!), and their
2045  // allocations aren't the same, the pointers are not equal.
2046  //
2047  // Note that it's not necessary to check for LHS being a global variable
2048  // address, due to canonicalization and constant folding.
2049  if (isa<AllocaInst>(LHS) &&
2050  (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
2051  ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
2052  ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
2053  uint64_t LHSSize, RHSSize;
2054  if (LHSOffsetCI && RHSOffsetCI &&
2055  getObjectSize(LHS, LHSSize, DL, TLI) &&
2056  getObjectSize(RHS, RHSSize, DL, TLI)) {
2057  const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
2058  const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
2059  if (!LHSOffsetValue.isNegative() &&
2060  !RHSOffsetValue.isNegative() &&
2061  LHSOffsetValue.ult(LHSSize) &&
2062  RHSOffsetValue.ult(RHSSize)) {
2063  return ConstantInt::get(GetCompareTy(LHS),
2064  !CmpInst::isTrueWhenEqual(Pred));
2065  }
2066  }
2067 
2068  // Repeat the above check but this time without depending on DataLayout
2069  // or being able to compute a precise size.
2070  if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
2071  !cast<PointerType>(RHS->getType())->isEmptyTy() &&
2072  LHSOffset->isNullValue() &&
2073  RHSOffset->isNullValue())
2074  return ConstantInt::get(GetCompareTy(LHS),
2075  !CmpInst::isTrueWhenEqual(Pred));
2076  }
2077 
2078  // Even if an non-inbounds GEP occurs along the path we can still optimize
2079  // equality comparisons concerning the result. We avoid walking the whole
2080  // chain again by starting where the last calls to
2081  // stripAndComputeConstantOffsets left off and accumulate the offsets.
2082  Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
2083  Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
2084  if (LHS == RHS)
2085  return ConstantExpr::getICmp(Pred,
2086  ConstantExpr::getAdd(LHSOffset, LHSNoBound),
2087  ConstantExpr::getAdd(RHSOffset, RHSNoBound));
2088 
2089  // If one side of the equality comparison must come from a noalias call
2090  // (meaning a system memory allocation function), and the other side must
2091  // come from a pointer that cannot overlap with dynamically-allocated
2092  // memory within the lifetime of the current function (allocas, byval
2093  // arguments, globals), then determine the comparison result here.
2094  SmallVector<Value *, 8> LHSUObjs, RHSUObjs;
2095  GetUnderlyingObjects(LHS, LHSUObjs, DL);
2096  GetUnderlyingObjects(RHS, RHSUObjs, DL);
2097 
2098  // Is the set of underlying objects all noalias calls?
2099  auto IsNAC = [](ArrayRef<Value *> Objects) {
2100  return all_of(Objects, isNoAliasCall);
2101  };
2102 
2103  // Is the set of underlying objects all things which must be disjoint from
2104  // noalias calls. For allocas, we consider only static ones (dynamic
2105  // allocas might be transformed into calls to malloc not simultaneously
2106  // live with the compared-to allocation). For globals, we exclude symbols
2107  // that might be resolve lazily to symbols in another dynamically-loaded
2108  // library (and, thus, could be malloc'ed by the implementation).
2109  auto IsAllocDisjoint = [](ArrayRef<Value *> Objects) {
2110  return all_of(Objects, [](Value *V) {
2111  if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
2112  return AI->getParent() && AI->getFunction() && AI->isStaticAlloca();
2113  if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
2114  return (GV->hasLocalLinkage() || GV->hasHiddenVisibility() ||
2115  GV->hasProtectedVisibility() || GV->hasGlobalUnnamedAddr()) &&
2116  !GV->isThreadLocal();
2117  if (const Argument *A = dyn_cast<Argument>(V))
2118  return A->hasByValAttr();
2119  return false;
2120  });
2121  };
2122 
2123  if ((IsNAC(LHSUObjs) && IsAllocDisjoint(RHSUObjs)) ||
2124  (IsNAC(RHSUObjs) && IsAllocDisjoint(LHSUObjs)))
2125  return ConstantInt::get(GetCompareTy(LHS),
2126  !CmpInst::isTrueWhenEqual(Pred));
2127 
2128  // Fold comparisons for non-escaping pointer even if the allocation call
2129  // cannot be elided. We cannot fold malloc comparison to null. Also, the
2130  // dynamic allocation call could be either of the operands.
2131  Value *MI = nullptr;
2132  if (isAllocLikeFn(LHS, TLI) &&
2133  llvm::isKnownNonZero(RHS, DL, 0, nullptr, CxtI, DT))
2134  MI = LHS;
2135  else if (isAllocLikeFn(RHS, TLI) &&
2136  llvm::isKnownNonZero(LHS, DL, 0, nullptr, CxtI, DT))
2137  MI = RHS;
2138  // FIXME: We should also fold the compare when the pointer escapes, but the
2139  // compare dominates the pointer escape
2140  if (MI && !PointerMayBeCaptured(MI, true, true))
2141  return ConstantInt::get(GetCompareTy(LHS),
2143  }
2144 
2145  // Otherwise, fail.
2146  return nullptr;
2147 }
2148 
2149 /// Fold an icmp when its operands have i1 scalar type.
2151  Value *RHS, const SimplifyQuery &Q) {
2152  Type *ITy = GetCompareTy(LHS); // The return type.
2153  Type *OpTy = LHS->getType(); // The operand type.
2154  if (!OpTy->isIntOrIntVectorTy(1))
2155  return nullptr;
2156 
2157  // A boolean compared to true/false can be simplified in 14 out of the 20
2158  // (10 predicates * 2 constants) possible combinations. Cases not handled here
2159  // require a 'not' of the LHS, so those must be transformed in InstCombine.
2160  if (match(RHS, m_Zero())) {
2161  switch (Pred) {
2162  case CmpInst::ICMP_NE: // X != 0 -> X
2163  case CmpInst::ICMP_UGT: // X >u 0 -> X
2164  case CmpInst::ICMP_SLT: // X <s 0 -> X
2165  return LHS;
2166 
2167  case CmpInst::ICMP_ULT: // X <u 0 -> false
2168  case CmpInst::ICMP_SGT: // X >s 0 -> false
2169  return getFalse(ITy);
2170 
2171  case CmpInst::ICMP_UGE: // X >=u 0 -> true
2172  case CmpInst::ICMP_SLE: // X <=s 0 -> true
2173  return getTrue(ITy);
2174 
2175  default: break;
2176  }
2177  } else if (match(RHS, m_One())) {
2178  switch (Pred) {
2179  case CmpInst::ICMP_EQ: // X == 1 -> X
2180  case CmpInst::ICMP_UGE: // X >=u 1 -> X
2181  case CmpInst::ICMP_SLE: // X <=s -1 -> X
2182  return LHS;
2183 
2184  case CmpInst::ICMP_UGT: // X >u 1 -> false
2185  case CmpInst::ICMP_SLT: // X <s -1 -> false
2186  return getFalse(ITy);
2187 
2188  case CmpInst::ICMP_ULE: // X <=u 1 -> true
2189  case CmpInst::ICMP_SGE: // X >=s -1 -> true
2190  return getTrue(ITy);
2191 
2192  default: break;
2193  }
2194  }
2195 
2196  switch (Pred) {
2197  default:
2198  break;
2199  case ICmpInst::ICMP_UGE:
2200  if (isImpliedCondition(RHS, LHS, Q.DL).getValueOr(false))
2201  return getTrue(ITy);
2202  break;
2203  case ICmpInst::ICMP_SGE:
2204  /// For signed comparison, the values for an i1 are 0 and -1
2205  /// respectively. This maps into a truth table of:
2206  /// LHS | RHS | LHS >=s RHS | LHS implies RHS
2207  /// 0 | 0 | 1 (0 >= 0) | 1
2208  /// 0 | 1 | 1 (0 >= -1) | 1
2209  /// 1 | 0 | 0 (-1 >= 0) | 0
2210  /// 1 | 1 | 1 (-1 >= -1) | 1
2211  if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2212  return getTrue(ITy);
2213  break;
2214  case ICmpInst::ICMP_ULE:
2215  if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2216  return getTrue(ITy);
2217  break;
2218  }
2219 
2220  return nullptr;
2221 }
2222 
2223 /// Try hard to fold icmp with zero RHS because this is a common case.
2225  Value *RHS, const SimplifyQuery &Q) {
2226  if (!match(RHS, m_Zero()))
2227  return nullptr;
2228 
2229  Type *ITy = GetCompareTy(LHS); // The return type.
2230  switch (Pred) {
2231  default:
2232  llvm_unreachable("Unknown ICmp predicate!");
2233  case ICmpInst::ICMP_ULT:
2234  return getFalse(ITy);
2235  case ICmpInst::ICMP_UGE:
2236  return getTrue(ITy);
2237  case ICmpInst::ICMP_EQ:
2238  case ICmpInst::ICMP_ULE:
2239  if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2240  return getFalse(ITy);
2241  break;
2242  case ICmpInst::ICMP_NE:
2243  case ICmpInst::ICMP_UGT:
2244  if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2245  return getTrue(ITy);
2246  break;
2247  case ICmpInst::ICMP_SLT: {
2248  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2249  if (LHSKnown.isNegative())
2250  return getTrue(ITy);
2251  if (LHSKnown.isNonNegative())
2252  return getFalse(ITy);
2253  break;
2254  }
2255  case ICmpInst::ICMP_SLE: {
2256  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2257  if (LHSKnown.isNegative())
2258  return getTrue(ITy);
2259  if (LHSKnown.isNonNegative() &&
2260  isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2261  return getFalse(ITy);
2262  break;
2263  }
2264  case ICmpInst::ICMP_SGE: {
2265  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2266  if (LHSKnown.isNegative())
2267  return getFalse(ITy);
2268  if (LHSKnown.isNonNegative())
2269  return getTrue(ITy);
2270  break;
2271  }
2272  case ICmpInst::ICMP_SGT: {
2273  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2274  if (LHSKnown.isNegative())
2275  return getFalse(ITy);
2276  if (LHSKnown.isNonNegative() &&
2277  isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2278  return getTrue(ITy);
2279  break;
2280  }
2281  }
2282 
2283  return nullptr;
2284 }
2285 
2286 /// Many binary operators with a constant operand have an easy-to-compute
2287 /// range of outputs. This can be used to fold a comparison to always true or
2288 /// always false.
2289 static void setLimitsForBinOp(BinaryOperator &BO, APInt &Lower, APInt &Upper) {
2290  unsigned Width = Lower.getBitWidth();
2291  const APInt *C;
2292  switch (BO.getOpcode()) {
2293  case Instruction::Add:
2294  if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
2295  // FIXME: If we have both nuw and nsw, we should reduce the range further.
2296  if (BO.hasNoUnsignedWrap()) {
2297  // 'add nuw x, C' produces [C, UINT_MAX].
2298  Lower = *C;
2299  } else if (BO.hasNoSignedWrap()) {
2300  if (C->isNegative()) {
2301  // 'add nsw x, -C' produces [SINT_MIN, SINT_MAX - C].
2302  Lower = APInt::getSignedMinValue(Width);
2303  Upper = APInt::getSignedMaxValue(Width) + *C + 1;
2304  } else {
2305  // 'add nsw x, +C' produces [SINT_MIN + C, SINT_MAX].
2306  Lower = APInt::getSignedMinValue(Width) + *C;
2307  Upper = APInt::getSignedMaxValue(Width) + 1;
2308  }
2309  }
2310  }
2311  break;
2312 
2313  case Instruction::And:
2314  if (match(BO.getOperand(1), m_APInt(C)))
2315  // 'and x, C' produces [0, C].
2316  Upper = *C + 1;
2317  break;
2318 
2319  case Instruction::Or:
2320  if (match(BO.getOperand(1), m_APInt(C)))
2321  // 'or x, C' produces [C, UINT_MAX].
2322  Lower = *C;
2323  break;
2324 
2325  case Instruction::AShr:
2326  if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
2327  // 'ashr x, C' produces [INT_MIN >> C, INT_MAX >> C].
2328  Lower = APInt::getSignedMinValue(Width).ashr(*C);
2329  Upper = APInt::getSignedMaxValue(Width).ashr(*C) + 1;
2330  } else if (match(BO.getOperand(0), m_APInt(C))) {
2331  unsigned ShiftAmount = Width - 1;
2332  if (!C->isNullValue() && BO.isExact())
2333  ShiftAmount = C->countTrailingZeros();
2334  if (C->isNegative()) {
2335  // 'ashr C, x' produces [C, C >> (Width-1)]
2336  Lower = *C;
2337  Upper = C->ashr(ShiftAmount) + 1;
2338  } else {
2339  // 'ashr C, x' produces [C >> (Width-1), C]
2340  Lower = C->ashr(ShiftAmount);
2341  Upper = *C + 1;
2342  }
2343  }
2344  break;
2345 
2346  case Instruction::LShr:
2347  if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
2348  // 'lshr x, C' produces [0, UINT_MAX >> C].
2349  Upper = APInt::getAllOnesValue(Width).lshr(*C) + 1;
2350  } else if (match(BO.getOperand(0), m_APInt(C))) {
2351  // 'lshr C, x' produces [C >> (Width-1), C].
2352  unsigned ShiftAmount = Width - 1;
2353  if (!C->isNullValue() && BO.isExact())
2354  ShiftAmount = C->countTrailingZeros();
2355  Lower = C->lshr(ShiftAmount);
2356  Upper = *C + 1;
2357  }
2358  break;
2359 
2360  case Instruction::Shl:
2361  if (match(BO.getOperand(0), m_APInt(C))) {
2362  if (BO.hasNoUnsignedWrap()) {
2363  // 'shl nuw C, x' produces [C, C << CLZ(C)]
2364  Lower = *C;
2365  Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
2366  } else if (BO.hasNoSignedWrap()) { // TODO: What if both nuw+nsw?
2367  if (C->isNegative()) {
2368  // 'shl nsw C, x' produces [C << CLO(C)-1, C]
2369  unsigned ShiftAmount = C->countLeadingOnes() - 1;
2370  Lower = C->shl(ShiftAmount);
2371  Upper = *C + 1;
2372  } else {
2373  // 'shl nsw C, x' produces [C, C << CLZ(C)-1]
2374  unsigned ShiftAmount = C->countLeadingZeros() - 1;
2375  Lower = *C;
2376  Upper = C->shl(ShiftAmount) + 1;
2377  }
2378  }
2379  }
2380  break;
2381 
2382  case Instruction::SDiv:
2383  if (match(BO.getOperand(1), m_APInt(C))) {
2384  APInt IntMin = APInt::getSignedMinValue(Width);
2385  APInt IntMax = APInt::getSignedMaxValue(Width);
2386  if (C->isAllOnesValue()) {
2387  // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
2388  // where C != -1 and C != 0 and C != 1
2389  Lower = IntMin + 1;
2390  Upper = IntMax + 1;
2391  } else if (C->countLeadingZeros() < Width - 1) {
2392  // 'sdiv x, C' produces [INT_MIN / C, INT_MAX / C]
2393  // where C != -1 and C != 0 and C != 1
2394  Lower = IntMin.sdiv(*C);
2395  Upper = IntMax.sdiv(*C);
2396  if (Lower.sgt(Upper))
2397  std::swap(Lower, Upper);
2398  Upper = Upper + 1;
2399  assert(Upper != Lower && "Upper part of range has wrapped!");
2400  }
2401  } else if (match(BO.getOperand(0), m_APInt(C))) {
2402  if (C->isMinSignedValue()) {
2403  // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
2404  Lower = *C;
2405  Upper = Lower.lshr(1) + 1;
2406  } else {
2407  // 'sdiv C, x' produces [-|C|, |C|].
2408  Upper = C->abs() + 1;
2409  Lower = (-Upper) + 1;
2410  }
2411  }
2412  break;
2413 
2414  case Instruction::UDiv:
2415  if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
2416  // 'udiv x, C' produces [0, UINT_MAX / C].
2417  Upper = APInt::getMaxValue(Width).udiv(*C) + 1;
2418  } else if (match(BO.getOperand(0), m_APInt(C))) {
2419  // 'udiv C, x' produces [0, C].
2420  Upper = *C + 1;
2421  }
2422  break;
2423 
2424  case Instruction::SRem:
2425  if (match(BO.getOperand(1), m_APInt(C))) {
2426  // 'srem x, C' produces (-|C|, |C|).
2427  Upper = C->abs();
2428  Lower = (-Upper) + 1;
2429  }
2430  break;
2431 
2432  case Instruction::URem:
2433  if (match(BO.getOperand(1), m_APInt(C)))
2434  // 'urem x, C' produces [0, C).
2435  Upper = *C;
2436  break;
2437 
2438  default:
2439  break;
2440  }
2441 }
2442 
2444  Value *RHS) {
2445  const APInt *C;
2446  if (!match(RHS, m_APInt(C)))
2447  return nullptr;
2448 
2449  // Rule out tautological comparisons (eg., ult 0 or uge 0).
2451  if (RHS_CR.isEmptySet())
2452  return ConstantInt::getFalse(GetCompareTy(RHS));
2453  if (RHS_CR.isFullSet())
2454  return ConstantInt::getTrue(GetCompareTy(RHS));
2455 
2456  // Find the range of possible values for binary operators.
2457  unsigned Width = C->getBitWidth();
2458  APInt Lower = APInt(Width, 0);
2459  APInt Upper = APInt(Width, 0);
2460  if (auto *BO = dyn_cast<BinaryOperator>(LHS))
2461  setLimitsForBinOp(*BO, Lower, Upper);
2462 
2463  ConstantRange LHS_CR =
2464  Lower != Upper ? ConstantRange(Lower, Upper) : ConstantRange(Width, true);
2465 
2466  if (auto *I = dyn_cast<Instruction>(LHS))
2467  if (auto *Ranges = I->getMetadata(LLVMContext::MD_range))
2468  LHS_CR = LHS_CR.intersectWith(getConstantRangeFromMetadata(*Ranges));
2469 
2470  if (!LHS_CR.isFullSet()) {
2471  if (RHS_CR.contains(LHS_CR))
2472  return ConstantInt::getTrue(GetCompareTy(RHS));
2473  if (RHS_CR.inverse().contains(LHS_CR))
2474  return ConstantInt::getFalse(GetCompareTy(RHS));
2475  }
2476 
2477  return nullptr;
2478 }
2479 
2480 /// TODO: A large part of this logic is duplicated in InstCombine's
2481 /// foldICmpBinOp(). We should be able to share that and avoid the code
2482 /// duplication.
2484  Value *RHS, const SimplifyQuery &Q,
2485  unsigned MaxRecurse) {
2486  Type *ITy = GetCompareTy(LHS); // The return type.
2487 
2488  BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2489  BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2490  if (MaxRecurse && (LBO || RBO)) {
2491  // Analyze the case when either LHS or RHS is an add instruction.
2492  Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
2493  // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2494  bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2495  if (LBO && LBO->getOpcode() == Instruction::Add) {
2496  A = LBO->getOperand(0);
2497  B = LBO->getOperand(1);
2498  NoLHSWrapProblem =
2499  ICmpInst::isEquality(Pred) ||
2500  (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2501  (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2502  }
2503  if (RBO && RBO->getOpcode() == Instruction::Add) {
2504  C = RBO->getOperand(0);
2505  D = RBO->getOperand(1);
2506  NoRHSWrapProblem =
2507  ICmpInst::isEquality(Pred) ||
2508  (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2509  (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2510  }
2511 
2512  // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2513  if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2514  if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2515  Constant::getNullValue(RHS->getType()), Q,
2516  MaxRecurse - 1))
2517  return V;
2518 
2519  // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2520  if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2521  if (Value *V =
2523  C == LHS ? D : C, Q, MaxRecurse - 1))
2524  return V;
2525 
2526  // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2527  if (A && C && (A == C || A == D || B == C || B == D) && NoLHSWrapProblem &&
2528  NoRHSWrapProblem) {
2529  // Determine Y and Z in the form icmp (X+Y), (X+Z).
2530  Value *Y, *Z;
2531  if (A == C) {
2532  // C + B == C + D -> B == D
2533  Y = B;
2534  Z = D;
2535  } else if (A == D) {
2536  // D + B == C + D -> B == C
2537  Y = B;
2538  Z = C;
2539  } else if (B == C) {
2540  // A + C == C + D -> A == D
2541  Y = A;
2542  Z = D;
2543  } else {
2544  assert(B == D);
2545  // A + D == C + D -> A == C
2546  Y = A;
2547  Z = C;
2548  }
2549  if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse - 1))
2550  return V;
2551  }
2552  }
2553 
2554  {
2555  Value *Y = nullptr;
2556  // icmp pred (or X, Y), X
2557  if (LBO && match(LBO, m_c_Or(m_Value(Y), m_Specific(RHS)))) {
2558  if (Pred == ICmpInst::ICMP_ULT)
2559  return getFalse(ITy);
2560  if (Pred == ICmpInst::ICMP_UGE)
2561  return getTrue(ITy);
2562 
2563  if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SGE) {
2564  KnownBits RHSKnown = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2565  KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2566  if (RHSKnown.isNonNegative() && YKnown.isNegative())
2567  return Pred == ICmpInst::ICMP_SLT ? getTrue(ITy) : getFalse(ITy);
2568  if (RHSKnown.isNegative() || YKnown.isNonNegative())
2569  return Pred == ICmpInst::ICMP_SLT ? getFalse(ITy) : getTrue(ITy);
2570  }
2571  }
2572  // icmp pred X, (or X, Y)
2573  if (RBO && match(RBO, m_c_Or(m_Value(Y), m_Specific(LHS)))) {
2574  if (Pred == ICmpInst::ICMP_ULE)
2575  return getTrue(ITy);
2576  if (Pred == ICmpInst::ICMP_UGT)
2577  return getFalse(ITy);
2578 
2579  if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SLE) {
2580  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2581  KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2582  if (LHSKnown.isNonNegative() && YKnown.isNegative())
2583  return Pred == ICmpInst::ICMP_SGT ? getTrue(ITy) : getFalse(ITy);
2584  if (LHSKnown.isNegative() || YKnown.isNonNegative())
2585  return Pred == ICmpInst::ICMP_SGT ? getFalse(ITy) : getTrue(ITy);
2586  }
2587  }
2588  }
2589 
2590  // icmp pred (and X, Y), X
2591  if (LBO && match(LBO, m_c_And(m_Value(), m_Specific(RHS)))) {
2592  if (Pred == ICmpInst::ICMP_UGT)
2593  return getFalse(ITy);
2594  if (Pred == ICmpInst::ICMP_ULE)
2595  return getTrue(ITy);
2596  }
2597  // icmp pred X, (and X, Y)
2598  if (RBO && match(RBO, m_c_And(m_Value(), m_Specific(LHS)))) {
2599  if (Pred == ICmpInst::ICMP_UGE)
2600  return getTrue(ITy);
2601  if (Pred == ICmpInst::ICMP_ULT)
2602  return getFalse(ITy);
2603  }
2604 
2605  // 0 - (zext X) pred C
2606  if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
2607  if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
2608  if (RHSC->getValue().isStrictlyPositive()) {
2609  if (Pred == ICmpInst::ICMP_SLT)
2610  return ConstantInt::getTrue(RHSC->getContext());
2611  if (Pred == ICmpInst::ICMP_SGE)
2612  return ConstantInt::getFalse(RHSC->getContext());
2613  if (Pred == ICmpInst::ICMP_EQ)
2614  return ConstantInt::getFalse(RHSC->getContext());
2615  if (Pred == ICmpInst::ICMP_NE)
2616  return ConstantInt::getTrue(RHSC->getContext());
2617  }
2618  if (RHSC->getValue().isNonNegative()) {
2619  if (Pred == ICmpInst::ICMP_SLE)
2620  return ConstantInt::getTrue(RHSC->getContext());
2621  if (Pred == ICmpInst::ICMP_SGT)
2622  return ConstantInt::getFalse(RHSC->getContext());
2623  }
2624  }
2625  }
2626 
2627  // icmp pred (urem X, Y), Y
2628  if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2629  switch (Pred) {
2630  default:
2631  break;
2632  case ICmpInst::ICMP_SGT:
2633  case ICmpInst::ICMP_SGE: {
2634  KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2635  if (!Known.isNonNegative())
2636  break;
2638  }
2639  case ICmpInst::ICMP_EQ:
2640  case ICmpInst::ICMP_UGT:
2641  case ICmpInst::ICMP_UGE:
2642  return getFalse(ITy);
2643  case ICmpInst::ICMP_SLT:
2644  case ICmpInst::ICMP_SLE: {
2645  KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2646  if (!Known.isNonNegative())
2647  break;
2649  }
2650  case ICmpInst::ICMP_NE:
2651  case ICmpInst::ICMP_ULT:
2652  case ICmpInst::ICMP_ULE:
2653  return getTrue(ITy);
2654  }
2655  }
2656 
2657  // icmp pred X, (urem Y, X)
2658  if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2659  switch (Pred) {
2660  default:
2661  break;
2662  case ICmpInst::ICMP_SGT:
2663  case ICmpInst::ICMP_SGE: {
2664  KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2665  if (!Known.isNonNegative())
2666  break;
2668  }
2669  case ICmpInst::ICMP_NE:
2670  case ICmpInst::ICMP_UGT:
2671  case ICmpInst::ICMP_UGE:
2672  return getTrue(ITy);
2673  case ICmpInst::ICMP_SLT:
2674  case ICmpInst::ICMP_SLE: {
2675  KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2676  if (!Known.isNonNegative())
2677  break;
2679  }
2680  case ICmpInst::ICMP_EQ:
2681  case ICmpInst::ICMP_ULT:
2682  case ICmpInst::ICMP_ULE:
2683  return getFalse(ITy);
2684  }
2685  }
2686 
2687  // x >> y <=u x
2688  // x udiv y <=u x.
2689  if (LBO && (match(LBO, m_LShr(m_Specific(RHS), m_Value())) ||
2690  match(LBO, m_UDiv(m_Specific(RHS), m_Value())))) {
2691  // icmp pred (X op Y), X
2692  if (Pred == ICmpInst::ICMP_UGT)
2693  return getFalse(ITy);
2694  if (Pred == ICmpInst::ICMP_ULE)
2695  return getTrue(ITy);
2696  }
2697 
2698  // x >=u x >> y
2699  // x >=u x udiv y.
2700  if (RBO && (match(RBO, m_LShr(m_Specific(LHS), m_Value())) ||
2701  match(RBO, m_UDiv(m_Specific(LHS), m_Value())))) {
2702  // icmp pred X, (X op Y)
2703  if (Pred == ICmpInst::ICMP_ULT)
2704  return getFalse(ITy);
2705  if (Pred == ICmpInst::ICMP_UGE)
2706  return getTrue(ITy);
2707  }
2708 
2709  // handle:
2710  // CI2 << X == CI
2711  // CI2 << X != CI
2712  //
2713  // where CI2 is a power of 2 and CI isn't
2714  if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
2715  const APInt *CI2Val, *CIVal = &CI->getValue();
2716  if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
2717  CI2Val->isPowerOf2()) {
2718  if (!CIVal->isPowerOf2()) {
2719  // CI2 << X can equal zero in some circumstances,
2720  // this simplification is unsafe if CI is zero.
2721  //
2722  // We know it is safe if:
2723  // - The shift is nsw, we can't shift out the one bit.
2724  // - The shift is nuw, we can't shift out the one bit.
2725  // - CI2 is one
2726  // - CI isn't zero
2727  if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
2728  CI2Val->isOneValue() || !CI->isZero()) {
2729  if (Pred == ICmpInst::ICMP_EQ)
2730  return ConstantInt::getFalse(RHS->getContext());
2731  if (Pred == ICmpInst::ICMP_NE)
2732  return ConstantInt::getTrue(RHS->getContext());
2733  }
2734  }
2735  if (CIVal->isSignMask() && CI2Val->isOneValue()) {
2736  if (Pred == ICmpInst::ICMP_UGT)
2737  return ConstantInt::getFalse(RHS->getContext());
2738  if (Pred == ICmpInst::ICMP_ULE)
2739  return ConstantInt::getTrue(RHS->getContext());
2740  }
2741  }
2742  }
2743 
2744  if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2745  LBO->getOperand(1) == RBO->getOperand(1)) {
2746  switch (LBO->getOpcode()) {
2747  default:
2748  break;
2749  case Instruction::UDiv:
2750  case Instruction::LShr:
2751  if (ICmpInst::isSigned(Pred) || !LBO->isExact() || !RBO->isExact())
2752  break;
2753  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2754  RBO->getOperand(0), Q, MaxRecurse - 1))
2755  return V;
2756  break;
2757  case Instruction::SDiv:
2758  if (!ICmpInst::isEquality(Pred) || !LBO->isExact() || !RBO->isExact())
2759  break;
2760  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2761  RBO->getOperand(0), Q, MaxRecurse - 1))
2762  return V;
2763  break;
2764  case Instruction::AShr:
2765  if (!LBO->isExact() || !RBO->isExact())
2766  break;
2767  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2768  RBO->getOperand(0), Q, MaxRecurse - 1))
2769  return V;
2770  break;
2771  case Instruction::Shl: {
2772  bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2773  bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2774  if (!NUW && !NSW)
2775  break;
2776  if (!NSW && ICmpInst::isSigned(Pred))
2777  break;
2778  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2779  RBO->getOperand(0), Q, MaxRecurse - 1))
2780  return V;
2781  break;
2782  }
2783  }
2784  }
2785  return nullptr;
2786 }
2787 
2788 /// Simplify integer comparisons where at least one operand of the compare
2789 /// matches an integer min/max idiom.
2791  Value *RHS, const SimplifyQuery &Q,
2792  unsigned MaxRecurse) {
2793  Type *ITy = GetCompareTy(LHS); // The return type.
2794  Value *A, *B;
2796  CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2797 
2798  // Signed variants on "max(a,b)>=a -> true".
2799  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2800  if (A != RHS)
2801  std::swap(A, B); // smax(A, B) pred A.
2802  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2803  // We analyze this as smax(A, B) pred A.
2804  P = Pred;
2805  } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2806  (A == LHS || B == LHS)) {
2807  if (A != LHS)
2808  std::swap(A, B); // A pred smax(A, B).
2809  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2810  // We analyze this as smax(A, B) swapped-pred A.
2811  P = CmpInst::getSwappedPredicate(Pred);
2812  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2813  (A == RHS || B == RHS)) {
2814  if (A != RHS)
2815  std::swap(A, B); // smin(A, B) pred A.
2816  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2817  // We analyze this as smax(-A, -B) swapped-pred -A.
2818  // Note that we do not need to actually form -A or -B thanks to EqP.
2819  P = CmpInst::getSwappedPredicate(Pred);
2820  } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2821  (A == LHS || B == LHS)) {
2822  if (A != LHS)
2823  std::swap(A, B); // A pred smin(A, B).
2824  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2825  // We analyze this as smax(-A, -B) pred -A.
2826  // Note that we do not need to actually form -A or -B thanks to EqP.
2827  P = Pred;
2828  }
2829  if (P != CmpInst::BAD_ICMP_PREDICATE) {
2830  // Cases correspond to "max(A, B) p A".
2831  switch (P) {
2832  default:
2833  break;
2834  case CmpInst::ICMP_EQ:
2835  case CmpInst::ICMP_SLE:
2836  // Equivalent to "A EqP B". This may be the same as the condition tested
2837  // in the max/min; if so, we can just return that.
2838  if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2839  return V;
2840  if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2841  return V;
2842  // Otherwise, see if "A EqP B" simplifies.
2843  if (MaxRecurse)
2844  if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
2845  return V;
2846  break;
2847  case CmpInst::ICMP_NE:
2848  case CmpInst::ICMP_SGT: {
2850  // Equivalent to "A InvEqP B". This may be the same as the condition
2851  // tested in the max/min; if so, we can just return that.
2852  if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2853  return V;
2854  if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2855  return V;
2856  // Otherwise, see if "A InvEqP B" simplifies.
2857  if (MaxRecurse)
2858  if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
2859  return V;
2860  break;
2861  }
2862  case CmpInst::ICMP_SGE:
2863  // Always true.
2864  return getTrue(ITy);
2865  case CmpInst::ICMP_SLT:
2866  // Always false.
2867  return getFalse(ITy);
2868  }
2869  }
2870 
2871  // Unsigned variants on "max(a,b)>=a -> true".
2873  if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2874  if (A != RHS)
2875  std::swap(A, B); // umax(A, B) pred A.
2876  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2877  // We analyze this as umax(A, B) pred A.
2878  P = Pred;
2879  } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2880  (A == LHS || B == LHS)) {
2881  if (A != LHS)
2882  std::swap(A, B); // A pred umax(A, B).
2883  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2884  // We analyze this as umax(A, B) swapped-pred A.
2885  P = CmpInst::getSwappedPredicate(Pred);
2886  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2887  (A == RHS || B == RHS)) {
2888  if (A != RHS)
2889  std::swap(A, B); // umin(A, B) pred A.
2890  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2891  // We analyze this as umax(-A, -B) swapped-pred -A.
2892  // Note that we do not need to actually form -A or -B thanks to EqP.
2893  P = CmpInst::getSwappedPredicate(Pred);
2894  } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2895  (A == LHS || B == LHS)) {
2896  if (A != LHS)
2897  std::swap(A, B); // A pred umin(A, B).
2898  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2899  // We analyze this as umax(-A, -B) pred -A.
2900  // Note that we do not need to actually form -A or -B thanks to EqP.
2901  P = Pred;
2902  }
2903  if (P != CmpInst::BAD_ICMP_PREDICATE) {
2904  // Cases correspond to "max(A, B) p A".
2905  switch (P) {
2906  default:
2907  break;
2908  case CmpInst::ICMP_EQ:
2909  case CmpInst::ICMP_ULE:
2910  // Equivalent to "A EqP B". This may be the same as the condition tested
2911  // in the max/min; if so, we can just return that.
2912  if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2913  return V;
2914  if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2915  return V;
2916  // Otherwise, see if "A EqP B" simplifies.
2917  if (MaxRecurse)
2918  if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
2919  return V;
2920  break;
2921  case CmpInst::ICMP_NE:
2922  case CmpInst::ICMP_UGT: {
2924  // Equivalent to "A InvEqP B". This may be the same as the condition
2925  // tested in the max/min; if so, we can just return that.
2926  if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2927  return V;
2928  if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2929  return V;
2930  // Otherwise, see if "A InvEqP B" simplifies.
2931  if (MaxRecurse)
2932  if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
2933  return V;
2934  break;
2935  }
2936  case CmpInst::ICMP_UGE:
2937  // Always true.
2938  return getTrue(ITy);
2939  case CmpInst::ICMP_ULT:
2940  // Always false.
2941  return getFalse(ITy);
2942  }
2943  }
2944 
2945  // Variants on "max(x,y) >= min(x,z)".
2946  Value *C, *D;
2947  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2948  match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2949  (A == C || A == D || B == C || B == D)) {
2950  // max(x, ?) pred min(x, ?).
2951  if (Pred == CmpInst::ICMP_SGE)
2952  // Always true.
2953  return getTrue(ITy);
2954  if (Pred == CmpInst::ICMP_SLT)
2955  // Always false.
2956  return getFalse(ITy);
2957  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2958  match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2959  (A == C || A == D || B == C || B == D)) {
2960  // min(x, ?) pred max(x, ?).
2961  if (Pred == CmpInst::ICMP_SLE)
2962  // Always true.
2963  return getTrue(ITy);
2964  if (Pred == CmpInst::ICMP_SGT)
2965  // Always false.
2966  return getFalse(ITy);
2967  } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2968  match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2969  (A == C || A == D || B == C || B == D)) {
2970  // max(x, ?) pred min(x, ?).
2971  if (Pred == CmpInst::ICMP_UGE)
2972  // Always true.
2973  return getTrue(ITy);
2974  if (Pred == CmpInst::ICMP_ULT)
2975  // Always false.
2976  return getFalse(ITy);
2977  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2978  match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2979  (A == C || A == D || B == C || B == D)) {
2980  // min(x, ?) pred max(x, ?).
2981  if (Pred == CmpInst::ICMP_ULE)
2982  // Always true.
2983  return getTrue(ITy);
2984  if (Pred == CmpInst::ICMP_UGT)
2985  // Always false.
2986  return getFalse(ITy);
2987  }
2988 
2989  return nullptr;
2990 }
2991 
2992 /// Given operands for an ICmpInst, see if we can fold the result.
2993 /// If not, this returns null.
2994 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2995  const SimplifyQuery &Q, unsigned MaxRecurse) {
2996  CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2997  assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
2998 
2999  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3000  if (Constant *CRHS = dyn_cast<Constant>(RHS))
3001  return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3002 
3003  // If we have a constant, make sure it is on the RHS.
3004  std::swap(LHS, RHS);
3005  Pred = CmpInst::getSwappedPredicate(Pred);
3006  }
3007 
3008  Type *ITy = GetCompareTy(LHS); // The return type.
3009 
3010  // icmp X, X -> true/false
3011  // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
3012  // because X could be 0.
3013  if (LHS == RHS || isa<UndefValue>(RHS))
3014  return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
3015 
3016  if (Value *V = simplifyICmpOfBools(Pred, LHS, RHS, Q))
3017  return V;
3018 
3019  if (Value *V = simplifyICmpWithZero(Pred, LHS, RHS, Q))
3020  return V;
3021 
3022  if (Value *V = simplifyICmpWithConstant(Pred, LHS, RHS))
3023  return V;
3024 
3025  // If both operands have range metadata, use the metadata
3026  // to simplify the comparison.
3027  if (isa<Instruction>(RHS) && isa<Instruction>(LHS)) {
3028  auto RHS_Instr = cast<Instruction>(RHS);
3029  auto LHS_Instr = cast<Instruction>(LHS);
3030 
3031  if (RHS_Instr->getMetadata(LLVMContext::MD_range) &&
3032  LHS_Instr->getMetadata(LLVMContext::MD_range)) {
3033  auto RHS_CR = getConstantRangeFromMetadata(
3034  *RHS_Instr->getMetadata(LLVMContext::MD_range));
3035  auto LHS_CR = getConstantRangeFromMetadata(
3036  *LHS_Instr->getMetadata(LLVMContext::MD_range));
3037 
3038  auto Satisfied_CR = ConstantRange::makeSatisfyingICmpRegion(Pred, RHS_CR);
3039  if (Satisfied_CR.contains(LHS_CR))
3040  return ConstantInt::getTrue(RHS->getContext());
3041 
3042  auto InversedSatisfied_CR = ConstantRange::makeSatisfyingICmpRegion(
3043  CmpInst::getInversePredicate(Pred), RHS_CR);
3044  if (InversedSatisfied_CR.contains(LHS_CR))
3045  return ConstantInt::getFalse(RHS->getContext());
3046  }
3047  }
3048 
3049  // Compare of cast, for example (zext X) != 0 -> X != 0
3050  if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
3051  Instruction *LI = cast<CastInst>(LHS);
3052  Value *SrcOp = LI->getOperand(0);
3053  Type *SrcTy = SrcOp->getType();
3054  Type *DstTy = LI->getType();
3055 
3056  // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
3057  // if the integer type is the same size as the pointer type.
3058  if (MaxRecurse && isa<PtrToIntInst>(LI) &&
3059  Q.DL.getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
3060  if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
3061  // Transfer the cast to the constant.
3062  if (Value *V = SimplifyICmpInst(Pred, SrcOp,
3063  ConstantExpr::getIntToPtr(RHSC, SrcTy),
3064  Q, MaxRecurse-1))
3065  return V;
3066  } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
3067  if (RI->getOperand(0)->getType() == SrcTy)
3068  // Compare without the cast.
3069  if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
3070  Q, MaxRecurse-1))
3071  return V;
3072  }
3073  }
3074 
3075  if (isa<ZExtInst>(LHS)) {
3076  // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
3077  // same type.
3078  if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
3079  if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3080  // Compare X and Y. Note that signed predicates become unsigned.
3082  SrcOp, RI->getOperand(0), Q,
3083  MaxRecurse-1))
3084  return V;
3085  }
3086  // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
3087  // too. If not, then try to deduce the result of the comparison.
3088  else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3089  // Compute the constant that would happen if we truncated to SrcTy then
3090  // reextended to DstTy.
3091  Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3092  Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
3093 
3094  // If the re-extended constant didn't change then this is effectively
3095  // also a case of comparing two zero-extended values.
3096  if (RExt == CI && MaxRecurse)
3098  SrcOp, Trunc, Q, MaxRecurse-1))
3099  return V;
3100 
3101  // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
3102  // there. Use this to work out the result of the comparison.
3103  if (RExt != CI) {
3104  switch (Pred) {
3105  default: llvm_unreachable("Unknown ICmp predicate!");
3106  // LHS <u RHS.
3107  case ICmpInst::ICMP_EQ:
3108  case ICmpInst::ICMP_UGT:
3109  case ICmpInst::ICMP_UGE:
3110  return ConstantInt::getFalse(CI->getContext());
3111 
3112  case ICmpInst::ICMP_NE:
3113  case ICmpInst::ICMP_ULT:
3114  case ICmpInst::ICMP_ULE:
3115  return ConstantInt::getTrue(CI->getContext());
3116 
3117  // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
3118  // is non-negative then LHS <s RHS.
3119  case ICmpInst::ICMP_SGT:
3120  case ICmpInst::ICMP_SGE:
3121  return CI->getValue().isNegative() ?
3122  ConstantInt::getTrue(CI->getContext()) :
3123  ConstantInt::getFalse(CI->getContext());
3124 
3125  case ICmpInst::ICMP_SLT:
3126  case ICmpInst::ICMP_SLE:
3127  return CI->getValue().isNegative() ?
3128  ConstantInt::getFalse(CI->getContext()) :
3129  ConstantInt::getTrue(CI->getContext());
3130  }
3131  }
3132  }
3133  }
3134 
3135  if (isa<SExtInst>(LHS)) {
3136  // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
3137  // same type.
3138  if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
3139  if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3140  // Compare X and Y. Note that the predicate does not change.
3141  if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
3142  Q, MaxRecurse-1))
3143  return V;
3144  }
3145  // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
3146  // too. If not, then try to deduce the result of the comparison.
3147  else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3148  // Compute the constant that would happen if we truncated to SrcTy then
3149  // reextended to DstTy.
3150  Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3151  Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
3152 
3153  // If the re-extended constant didn't change then this is effectively
3154  // also a case of comparing two sign-extended values.
3155  if (RExt == CI && MaxRecurse)
3156  if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
3157  return V;
3158 
3159  // Otherwise the upper bits of LHS are all equal, while RHS has varying
3160  // bits there. Use this to work out the result of the comparison.
3161  if (RExt != CI) {
3162  switch (Pred) {
3163  default: llvm_unreachable("Unknown ICmp predicate!");
3164  case ICmpInst::ICMP_EQ:
3165  return ConstantInt::getFalse(CI->getContext());
3166  case ICmpInst::ICMP_NE:
3167  return ConstantInt::getTrue(CI->getContext());
3168 
3169  // If RHS is non-negative then LHS <s RHS. If RHS is negative then
3170  // LHS >s RHS.
3171  case ICmpInst::ICMP_SGT:
3172  case ICmpInst::ICMP_SGE:
3173  return CI->getValue().isNegative() ?
3174  ConstantInt::getTrue(CI->getContext()) :
3175  ConstantInt::getFalse(CI->getContext());
3176  case ICmpInst::ICMP_SLT:
3177  case ICmpInst::ICMP_SLE:
3178  return CI->getValue().isNegative() ?
3179  ConstantInt::getFalse(CI->getContext()) :
3180  ConstantInt::getTrue(CI->getContext());
3181 
3182  // If LHS is non-negative then LHS <u RHS. If LHS is negative then
3183  // LHS >u RHS.
3184  case ICmpInst::ICMP_UGT:
3185  case ICmpInst::ICMP_UGE:
3186  // Comparison is true iff the LHS <s 0.
3187  if (MaxRecurse)
3188  if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
3189  Constant::getNullValue(SrcTy),
3190  Q, MaxRecurse-1))
3191  return V;
3192  break;
3193  case ICmpInst::ICMP_ULT:
3194  case ICmpInst::ICMP_ULE:
3195  // Comparison is true iff the LHS >=s 0.
3196  if (MaxRecurse)
3197  if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
3198  Constant::getNullValue(SrcTy),
3199  Q, MaxRecurse-1))
3200  return V;
3201  break;
3202  }
3203  }
3204  }
3205  }
3206  }
3207 
3208  // icmp eq|ne X, Y -> false|true if X != Y
3209  if (ICmpInst::isEquality(Pred) &&
3210  isKnownNonEqual(LHS, RHS, Q.DL, Q.AC, Q.CxtI, Q.DT)) {
3211  return Pred == ICmpInst::ICMP_NE ? getTrue(ITy) : getFalse(ITy);
3212  }
3213 
3214  if (Value *V = simplifyICmpWithBinOp(Pred, LHS, RHS, Q, MaxRecurse))
3215  return V;
3216 
3217  if (Value *V = simplifyICmpWithMinMax(Pred, LHS, RHS, Q, MaxRecurse))
3218  return V;
3219 
3220  // Simplify comparisons of related pointers using a powerful, recursive
3221  // GEP-walk when we have target data available..
3222  if (LHS->getType()->isPointerTy())
3223  if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI, LHS,
3224  RHS))
3225  return C;
3226  if (auto *CLHS = dyn_cast<PtrToIntOperator>(LHS))
3227  if (auto *CRHS = dyn_cast<PtrToIntOperator>(RHS))
3228  if (Q.DL.getTypeSizeInBits(CLHS->getPointerOperandType()) ==
3229  Q.DL.getTypeSizeInBits(CLHS->getType()) &&
3230  Q.DL.getTypeSizeInBits(CRHS->getPointerOperandType()) ==
3231  Q.DL.getTypeSizeInBits(CRHS->getType()))
3232  if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI,
3233  CLHS->getPointerOperand(),
3234  CRHS->getPointerOperand()))
3235  return C;
3236 
3237  if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
3238  if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
3239  if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
3240  GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
3241  (ICmpInst::isEquality(Pred) ||
3242  (GLHS->isInBounds() && GRHS->isInBounds() &&
3243  Pred == ICmpInst::getSignedPredicate(Pred)))) {
3244  // The bases are equal and the indices are constant. Build a constant
3245  // expression GEP with the same indices and a null base pointer to see
3246  // what constant folding can make out of it.
3247  Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
3248  SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
3250  GLHS->getSourceElementType(), Null, IndicesLHS);
3251 
3252  SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
3254  GLHS->getSourceElementType(), Null, IndicesRHS);
3255  return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
3256  }
3257  }
3258  }
3259 
3260  // If the comparison is with the result of a select instruction, check whether
3261  // comparing with either branch of the select always yields the same value.
3262  if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3263  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3264  return V;
3265 
3266  // If the comparison is with the result of a phi instruction, check whether
3267  // doing the compare with each incoming phi value yields a common result.
3268  if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3269  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3270  return V;
3271 
3272  return nullptr;
3273 }
3274 
3275 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3276  const SimplifyQuery &Q) {
3277  return ::SimplifyICmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
3278 }
3279 
3280 /// Given operands for an FCmpInst, see if we can fold the result.
3281 /// If not, this returns null.
3282 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3283  FastMathFlags FMF, const SimplifyQuery &Q,
3284  unsigned MaxRecurse) {
3285  CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3286  assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
3287 
3288  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3289  if (Constant *CRHS = dyn_cast<Constant>(RHS))
3290  return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3291 
3292  // If we have a constant, make sure it is on the RHS.
3293  std::swap(LHS, RHS);
3294  Pred = CmpInst::getSwappedPredicate(Pred);
3295  }
3296 
3297  // Fold trivial predicates.
3298  Type *RetTy = GetCompareTy(LHS);
3299  if (Pred == FCmpInst::FCMP_FALSE)
3300  return getFalse(RetTy);
3301  if (Pred == FCmpInst::FCMP_TRUE)
3302  return getTrue(RetTy);
3303 
3304  // UNO/ORD predicates can be trivially folded if NaNs are ignored.
3305  if (FMF.noNaNs()) {
3306  if (Pred == FCmpInst::FCMP_UNO)
3307  return getFalse(RetTy);
3308  if (Pred == FCmpInst::FCMP_ORD)
3309  return getTrue(RetTy);
3310  }
3311 
3312  // fcmp pred x, undef and fcmp pred undef, x
3313  // fold to true if unordered, false if ordered
3314  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS)) {
3315  // Choosing NaN for the undef will always make unordered comparison succeed
3316  // and ordered comparison fail.
3317  return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred));
3318  }
3319 
3320  // fcmp x,x -> true/false. Not all compares are foldable.
3321  if (LHS == RHS) {
3322  if (CmpInst::isTrueWhenEqual(Pred))
3323  return getTrue(RetTy);
3324  if (CmpInst::isFalseWhenEqual(Pred))
3325  return getFalse(RetTy);
3326  }
3327 
3328  // Handle fcmp with constant RHS.
3329  const APFloat *C;
3330  if (match(RHS, m_APFloat(C))) {
3331  // If the constant is a nan, see if we can fold the comparison based on it.
3332  if (C->isNaN()) {
3333  if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
3334  return getFalse(RetTy);
3335  assert(FCmpInst::isUnordered(Pred) &&
3336  "Comparison must be either ordered or unordered!");
3337  // True if unordered.
3338  return getTrue(RetTy);
3339  }
3340  // Check whether the constant is an infinity.
3341  if (C->isInfinity()) {
3342  if (C->isNegative()) {
3343  switch (Pred) {
3344  case FCmpInst::FCMP_OLT:
3345  // No value is ordered and less than negative infinity.
3346  return getFalse(RetTy);
3347  case FCmpInst::FCMP_UGE:
3348  // All values are unordered with or at least negative infinity.
3349  return getTrue(RetTy);
3350  default:
3351  break;
3352  }
3353  } else {
3354  switch (Pred) {
3355  case FCmpInst::FCMP_OGT:
3356  // No value is ordered and greater than infinity.
3357  return getFalse(RetTy);
3358  case FCmpInst::FCMP_ULE:
3359  // All values are unordered with and at most infinity.
3360  return getTrue(RetTy);
3361  default:
3362  break;
3363  }
3364  }
3365  }
3366  if (C->isZero()) {
3367  switch (Pred) {
3368  case FCmpInst::FCMP_UGE:
3369  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3370  return getTrue(RetTy);
3371  break;
3372  case FCmpInst::FCMP_OLT:
3373  // X < 0
3374  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3375  return getFalse(RetTy);
3376  break;
3377  default:
3378  break;
3379  }
3380  } else if (C->isNegative()) {
3381  assert(!C->isNaN() && "Unexpected NaN constant!");
3382  // TODO: We can catch more cases by using a range check rather than
3383  // relying on CannotBeOrderedLessThanZero.
3384  switch (Pred) {
3385  case FCmpInst::FCMP_UGE:
3386  case FCmpInst::FCMP_UGT:
3387  case FCmpInst::FCMP_UNE:
3388  // (X >= 0) implies (X > C) when (C < 0)
3389  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3390  return getTrue(RetTy);
3391  break;
3392  case FCmpInst::FCMP_OEQ:
3393  case FCmpInst::FCMP_OLE:
3394  case FCmpInst::FCMP_OLT:
3395  // (X >= 0) implies !(X < C) when (C < 0)
3396  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3397  return getFalse(RetTy);
3398  break;
3399  default:
3400  break;
3401  }
3402  }
3403  }
3404 
3405  // If the comparison is with the result of a select instruction, check whether
3406  // comparing with either branch of the select always yields the same value.
3407  if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3408  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3409  return V;
3410 
3411  // If the comparison is with the result of a phi instruction, check whether
3412  // doing the compare with each incoming phi value yields a common result.
3413  if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3414  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3415  return V;
3416 
3417  return nullptr;
3418 }
3419 
3420 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3421  FastMathFlags FMF, const SimplifyQuery &Q) {
3422  return ::SimplifyFCmpInst(Predicate, LHS, RHS, FMF, Q, RecursionLimit);
3423 }
3424 
3425 /// See if V simplifies when its operand Op is replaced with RepOp.
3426 static const Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
3427  const SimplifyQuery &Q,
3428  unsigned MaxRecurse) {
3429  // Trivial replacement.
3430  if (V == Op)
3431  return RepOp;
3432 
3433  // We cannot replace a constant, and shouldn't even try.
3434  if (isa<Constant>(Op))
3435  return nullptr;
3436 
3437  auto *I = dyn_cast<Instruction>(V);
3438  if (!I)
3439  return nullptr;
3440 
3441  // If this is a binary operator, try to simplify it with the replaced op.
3442  if (auto *B = dyn_cast<BinaryOperator>(I)) {
3443  // Consider:
3444  // %cmp = icmp eq i32 %x, 2147483647
3445  // %add = add nsw i32 %x, 1
3446  // %sel = select i1 %cmp, i32 -2147483648, i32 %add
3447  //
3448  // We can't replace %sel with %add unless we strip away the flags.
3449  if (isa<OverflowingBinaryOperator>(B))
3450  if (B->hasNoSignedWrap() || B->hasNoUnsignedWrap())
3451  return nullptr;
3452  if (isa<PossiblyExactOperator>(B))
3453  if (B->isExact())
3454  return nullptr;
3455 
3456  if (MaxRecurse) {
3457  if (B->getOperand(0) == Op)
3458  return SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), Q,
3459  MaxRecurse - 1);
3460  if (B->getOperand(1) == Op)
3461  return SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, Q,
3462  MaxRecurse - 1);
3463  }
3464  }
3465 
3466  // Same for CmpInsts.
3467  if (CmpInst *C = dyn_cast<CmpInst>(I)) {
3468  if (MaxRecurse) {
3469  if (C->getOperand(0) == Op)
3470  return SimplifyCmpInst(C->getPredicate(), RepOp, C->getOperand(1), Q,
3471  MaxRecurse - 1);
3472  if (C->getOperand(1) == Op)
3473  return SimplifyCmpInst(C->getPredicate(), C->getOperand(0), RepOp, Q,
3474  MaxRecurse - 1);
3475  }
3476  }
3477 
3478  // TODO: We could hand off more cases to instsimplify here.
3479 
3480  // If all operands are constant after substituting Op for RepOp then we can
3481  // constant fold the instruction.
3482  if (Constant *CRepOp = dyn_cast<Constant>(RepOp)) {
3483  // Build a list of all constant operands.
3484  SmallVector<Constant *, 8> ConstOps;
3485  for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
3486  if (I->getOperand(i) == Op)
3487  ConstOps.push_back(CRepOp);
3488  else if (Constant *COp = dyn_cast<Constant>(I->getOperand(i)))
3489  ConstOps.push_back(COp);
3490  else
3491  break;
3492  }
3493 
3494  // All operands were constants, fold it.
3495  if (ConstOps.size() == I->getNumOperands()) {
3496  if (CmpInst *C = dyn_cast<CmpInst>(I))
3497  return ConstantFoldCompareInstOperands(C->getPredicate(), ConstOps[0],
3498  ConstOps[1], Q.DL, Q.TLI);
3499 
3500  if (LoadInst *LI = dyn_cast<LoadInst>(I))
3501  if (!LI->isVolatile())
3502  return ConstantFoldLoadFromConstPtr(ConstOps[0], LI->getType(), Q.DL);
3503 
3504  return ConstantFoldInstOperands(I, ConstOps, Q.DL, Q.TLI);
3505  }
3506  }
3507 
3508  return nullptr;
3509 }
3510 
3511 /// Try to simplify a select instruction when its condition operand is an
3512 /// integer comparison where one operand of the compare is a constant.
3513 static Value *simplifySelectBitTest(Value *TrueVal, Value *FalseVal, Value *X,
3514  const APInt *Y, bool TrueWhenUnset) {
3515  const APInt *C;
3516 
3517  // (X & Y) == 0 ? X & ~Y : X --> X
3518  // (X & Y) != 0 ? X & ~Y : X --> X & ~Y
3519  if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) &&
3520  *Y == ~*C)
3521  return TrueWhenUnset ? FalseVal : TrueVal;
3522 
3523  // (X & Y) == 0 ? X : X & ~Y --> X & ~Y
3524  // (X & Y) != 0 ? X : X & ~Y --> X
3525  if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) &&
3526  *Y == ~*C)
3527  return TrueWhenUnset ? FalseVal : TrueVal;
3528 
3529  if (Y->isPowerOf2()) {
3530  // (X & Y) == 0 ? X | Y : X --> X | Y
3531  // (X & Y) != 0 ? X | Y : X --> X
3532  if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) &&
3533  *Y == *C)
3534  return TrueWhenUnset ? TrueVal : FalseVal;
3535 
3536  // (X & Y) == 0 ? X : X | Y --> X
3537  // (X & Y) != 0 ? X : X | Y --> X | Y
3538  if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) &&
3539  *Y == *C)
3540  return TrueWhenUnset ? TrueVal : FalseVal;
3541  }
3542 
3543  return nullptr;
3544 }
3545 
3546 /// An alternative way to test if a bit is set or not uses sgt/slt instead of
3547 /// eq/ne.
3549  ICmpInst::Predicate Pred,
3550  Value *TrueVal, Value *FalseVal) {
3551  Value *X;
3552  APInt Mask;
3553  if (!decomposeBitTestICmp(CmpLHS, CmpRHS, Pred, X, Mask))
3554  return nullptr;
3555 
3556  return simplifySelectBitTest(TrueVal, FalseVal, X, &Mask,
3557  Pred == ICmpInst::ICMP_EQ);
3558 }
3559 
3560 /// Try to simplify a select instruction when its condition operand is an
3561 /// integer comparison.
3562 static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
3563  Value *FalseVal, const SimplifyQuery &Q,
3564  unsigned MaxRecurse) {
3565  ICmpInst::Predicate Pred;
3566  Value *CmpLHS, *CmpRHS;
3567  if (!match(CondVal, m_ICmp(Pred, m_Value(CmpLHS), m_Value(CmpRHS))))
3568  return nullptr;
3569 
3570  if (ICmpInst::isEquality(Pred) && match(CmpRHS, m_Zero())) {
3571  Value *X;
3572  const APInt *Y;
3573  if (match(CmpLHS, m_And(m_Value(X), m_APInt(Y))))
3574  if (Value *V = simplifySelectBitTest(TrueVal, FalseVal, X, Y,
3575  Pred == ICmpInst::ICMP_EQ))
3576  return V;
3577  }
3578 
3579  // Check for other compares that behave like bit test.
3580  if (Value *V = simplifySelectWithFakeICmpEq(CmpLHS, CmpRHS, Pred,
3581  TrueVal, FalseVal))
3582  return V;
3583 
3584  if (CondVal->hasOneUse()) {
3585  const APInt *C;
3586  if (match(CmpRHS, m_APInt(C))) {
3587  // X < MIN ? T : F --> F
3588  if (Pred == ICmpInst::ICMP_SLT && C->isMinSignedValue())
3589  return FalseVal;
3590  // X < MIN ? T : F --> F
3591  if (Pred == ICmpInst::ICMP_ULT && C->isMinValue())
3592  return FalseVal;
3593  // X > MAX ? T : F --> F
3594  if (Pred == ICmpInst::ICMP_SGT && C->isMaxSignedValue())
3595  return FalseVal;
3596  // X > MAX ? T : F --> F
3597  if (Pred == ICmpInst::ICMP_UGT && C->isMaxValue())
3598  return FalseVal;
3599  }
3600  }
3601 
3602  // If we have an equality comparison, then we know the value in one of the
3603  // arms of the select. See if substituting this value into the arm and
3604  // simplifying the result yields the same value as the other arm.
3605  if (Pred == ICmpInst::ICMP_EQ) {
3606  if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3607  TrueVal ||
3608  SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3609  TrueVal)
3610  return FalseVal;
3611  if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3612  FalseVal ||
3613  SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3614  FalseVal)
3615  return FalseVal;
3616  } else if (Pred == ICmpInst::ICMP_NE) {
3617  if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3618  FalseVal ||
3619  SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3620  FalseVal)
3621  return TrueVal;
3622  if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3623  TrueVal ||
3624  SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3625  TrueVal)
3626  return TrueVal;
3627  }
3628 
3629  return nullptr;
3630 }
3631 
3632 /// Given operands for a SelectInst, see if we can fold the result.
3633 /// If not, this returns null.
3634 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
3635  Value *FalseVal, const SimplifyQuery &Q,
3636  unsigned MaxRecurse) {
3637  // select true, X, Y -> X
3638  // select false, X, Y -> Y
3639  if (Constant *CB = dyn_cast<Constant>(CondVal)) {
3640  if (Constant *CT = dyn_cast<Constant>(TrueVal))
3641  if (Constant *CF = dyn_cast<Constant>(FalseVal))
3642  return ConstantFoldSelectInstruction(CB, CT, CF);
3643  if (CB->isAllOnesValue())
3644  return TrueVal;
3645  if (CB->isNullValue())
3646  return FalseVal;
3647  }
3648 
3649  // select C, X, X -> X
3650  if (TrueVal == FalseVal)
3651  return TrueVal;
3652 
3653  if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
3654  if (isa<Constant>(FalseVal))
3655  return FalseVal;
3656  return TrueVal;
3657  }
3658  if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
3659  return FalseVal;
3660  if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
3661  return TrueVal;
3662 
3663  if (Value *V =
3664  simplifySelectWithICmpCond(CondVal, TrueVal, FalseVal, Q, MaxRecurse))
3665  return V;
3666 
3667  return nullptr;
3668 }
3669 
3670 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3671  const SimplifyQuery &Q) {
3672  return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Q, RecursionLimit);
3673 }
3674 
3675 /// Given operands for an GetElementPtrInst, see if we can fold the result.
3676 /// If not, this returns null.
3678  const SimplifyQuery &Q, unsigned) {
3679  // The type of the GEP pointer operand.
3680  unsigned AS =
3681  cast<PointerType>(Ops[0]->getType()->getScalarType())->getAddressSpace();
3682 
3683  // getelementptr P -> P.
3684  if (Ops.size() == 1)
3685  return Ops[0];
3686 
3687  // Compute the (pointer) type returned by the GEP instruction.
3688  Type *LastType = GetElementPtrInst::getIndexedType(SrcTy, Ops.slice(1));
3689  Type *GEPTy = PointerType::get(LastType, AS);
3690  if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
3691  GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3692  else if (VectorType *VT = dyn_cast<VectorType>(Ops[1]->getType()))
3693  GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3694 
3695  if (isa<UndefValue>(Ops[0]))
3696  return UndefValue::get(GEPTy);
3697 
3698  if (Ops.size() == 2) {
3699  // getelementptr P, 0 -> P.
3700  if (match(Ops[1], m_Zero()))
3701  return Ops[0];
3702 
3703  Type *Ty = SrcTy;
3704  if (Ty->isSized()) {
3705  Value *P;
3706  uint64_t C;
3707  uint64_t TyAllocSize = Q.DL.getTypeAllocSize(Ty);
3708  // getelementptr P, N -> P if P points to a type of zero size.
3709  if (TyAllocSize == 0)
3710  return Ops[0];
3711 
3712  // The following transforms are only safe if the ptrtoint cast
3713  // doesn't truncate the pointers.
3714  if (Ops[1]->getType()->getScalarSizeInBits() ==
3715  Q.DL.getPointerSizeInBits(AS)) {
3716  auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
3717  if (match(P, m_Zero()))
3718  return Constant::getNullValue(GEPTy);
3719  Value *Temp;
3720  if (match(P, m_PtrToInt(m_Value(Temp))))
3721  if (Temp->getType() == GEPTy)
3722  return Temp;
3723  return nullptr;
3724  };
3725 
3726  // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
3727  if (TyAllocSize == 1 &&
3728  match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
3729  if (Value *R = PtrToIntOrZero(P))
3730  return R;
3731 
3732  // getelementptr V, (ashr (sub P, V), C) -> Q
3733  // if P points to a type of size 1 << C.
3734  if (match(Ops[1],
3735  m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3736  m_ConstantInt(C))) &&
3737  TyAllocSize == 1ULL << C)
3738  if (Value *R = PtrToIntOrZero(P))
3739  return R;
3740 
3741  // getelementptr V, (sdiv (sub P, V), C) -> Q
3742  // if P points to a type of size C.
3743  if (match(Ops[1],
3744  m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3745  m_SpecificInt(TyAllocSize))))
3746  if (Value *R = PtrToIntOrZero(P))
3747  return R;
3748  }
3749  }
3750  }
3751 
3752  if (Q.DL.getTypeAllocSize(LastType) == 1 &&
3753  all_of(Ops.slice(1).drop_back(1),
3754  [](Value *Idx) { return match(Idx, m_Zero()); })) {
3755  unsigned PtrWidth =
3756  Q.DL.getPointerSizeInBits(Ops[0]->getType()->getPointerAddressSpace());
3757  if (Q.DL.getTypeSizeInBits(Ops.back()->getType()) == PtrWidth) {
3758  APInt BasePtrOffset(PtrWidth, 0);
3759  Value *StrippedBasePtr =
3760  Ops[0]->stripAndAccumulateInBoundsConstantOffsets(Q.DL,
3761  BasePtrOffset);
3762 
3763  // gep (gep V, C), (sub 0, V) -> C
3764  if (match(Ops.back(),
3765  m_Sub(m_Zero(), m_PtrToInt(m_Specific(StrippedBasePtr))))) {
3766  auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset);
3767  return ConstantExpr::getIntToPtr(CI, GEPTy);
3768  }
3769  // gep (gep V, C), (xor V, -1) -> C-1
3770  if (match(Ops.back(),
3771  m_Xor(m_PtrToInt(m_Specific(StrippedBasePtr)), m_AllOnes()))) {
3772  auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset - 1);
3773  return ConstantExpr::getIntToPtr(CI, GEPTy);
3774  }
3775  }
3776  }
3777 
3778  // Check to see if this is constant foldable.
3779  if (!all_of(Ops, [](Value *V) { return isa<Constant>(V); }))
3780  return nullptr;
3781 
3782  auto *CE = ConstantExpr::getGetElementPtr(SrcTy, cast<Constant>(Ops[0]),
3783  Ops.slice(1));
3784  if (auto *CEFolded = ConstantFoldConstant(CE, Q.DL))
3785  return CEFolded;
3786  return CE;
3787 }
3788 
3790  const SimplifyQuery &Q) {
3791  return ::SimplifyGEPInst(SrcTy, Ops, Q, RecursionLimit);
3792 }
3793 
3794 /// Given operands for an InsertValueInst, see if we can fold the result.
3795 /// If not, this returns null.
3797  ArrayRef<unsigned> Idxs, const SimplifyQuery &Q,
3798  unsigned) {
3799  if (Constant *CAgg = dyn_cast<Constant>(Agg))
3800  if (Constant *CVal = dyn_cast<Constant>(Val))
3801  return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
3802 
3803  // insertvalue x, undef, n -> x
3804  if (match(Val, m_Undef()))
3805  return Agg;
3806 
3807  // insertvalue x, (extractvalue y, n), n
3808  if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
3809  if (EV->getAggregateOperand()->getType() == Agg->getType() &&
3810  EV->getIndices() == Idxs) {
3811  // insertvalue undef, (extractvalue y, n), n -> y
3812  if (match(Agg, m_Undef()))
3813  return EV->getAggregateOperand();
3814 
3815  // insertvalue y, (extractvalue y, n), n -> y
3816  if (Agg == EV->getAggregateOperand())
3817  return Agg;
3818  }
3819 
3820  return nullptr;
3821 }
3822 
3824  ArrayRef<unsigned> Idxs,
3825  const SimplifyQuery &Q) {
3827 }
3828 
3830  const SimplifyQuery &Q) {
3831  // Try to constant fold.
3832  auto *VecC = dyn_cast<Constant>(Vec);
3833  auto *ValC = dyn_cast<Constant>(Val);
3834  auto *IdxC = dyn_cast<Constant>(Idx);
3835  if (VecC && ValC && IdxC)
3836  return ConstantFoldInsertElementInstruction(VecC, ValC, IdxC);
3837 
3838  // Fold into undef if index is out of bounds.
3839  if (auto *CI = dyn_cast<ConstantInt>(Idx)) {
3840  uint64_t NumElements = cast<VectorType>(Vec->getType())->getNumElements();
3841 
3842  if (CI->uge(NumElements))
3843  return UndefValue::get(Vec->getType());
3844  }
3845 
3846  // TODO: We should also fold if index is iteslf an undef.
3847 
3848  return nullptr;
3849 }
3850 
3851 /// Given operands for an ExtractValueInst, see if we can fold the result.
3852 /// If not, this returns null.
3854  const SimplifyQuery &, unsigned) {
3855  if (auto *CAgg = dyn_cast<Constant>(Agg))
3856  return ConstantFoldExtractValueInstruction(CAgg, Idxs);
3857 
3858  // extractvalue x, (insertvalue y, elt, n), n -> elt
3859  unsigned NumIdxs = Idxs.size();
3860  for (auto *IVI = dyn_cast<InsertValueInst>(Agg); IVI != nullptr;
3861  IVI = dyn_cast<InsertValueInst>(IVI->getAggregateOperand())) {
3862  ArrayRef<unsigned> InsertValueIdxs = IVI->getIndices();
3863  unsigned NumInsertValueIdxs = InsertValueIdxs.size();
3864  unsigned NumCommonIdxs = std::min(NumInsertValueIdxs, NumIdxs);
3865  if (InsertValueIdxs.slice(0, NumCommonIdxs) ==
3866  Idxs.slice(0, NumCommonIdxs)) {
3867  if (NumIdxs == NumInsertValueIdxs)
3868  return IVI->getInsertedValueOperand();
3869  break;
3870  }
3871  }
3872 
3873  return nullptr;
3874 }
3875 
3877  const SimplifyQuery &Q) {
3879 }
3880 
3881 /// Given operands for an ExtractElementInst, see if we can fold the result.
3882 /// If not, this returns null.
3884  unsigned) {
3885  if (auto *CVec = dyn_cast<Constant>(Vec)) {
3886  if (auto *CIdx = dyn_cast<Constant>(Idx))
3887  return ConstantFoldExtractElementInstruction(CVec, CIdx);
3888 
3889  // The index is not relevant if our vector is a splat.
3890  if (auto *Splat = CVec->getSplatValue())
3891  return Splat;
3892 
3893  if (isa<UndefValue>(Vec))
3894  return UndefValue::get(Vec->getType()->getVectorElementType());
3895  }
3896 
3897  // If extracting a specified index from the vector, see if we can recursively
3898  // find a previously computed scalar that was inserted into the vector.
3899  if (auto *IdxC = dyn_cast<ConstantInt>(Idx))
3900  if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue()))
3901  return Elt;
3902 
3903  // An undef extract index can be arbitrarily chosen to be an out-of-range
3904  // index value, which would result in the instruction being undef.
3905  if (isa<UndefValue>(Idx))
3906  return UndefValue::get(Vec->getType()->getVectorElementType());
3907 
3908  return nullptr;
3909 }
3910 
3912  const SimplifyQuery &Q) {
3914 }
3915 
3916 /// See if we can fold the given phi. If not, returns null.
3917 static Value *SimplifyPHINode(PHINode *PN, const SimplifyQuery &Q) {
3918  // If all of the PHI's incoming values are the same then replace the PHI node
3919  // with the common value.
3920  Value *CommonValue = nullptr;
3921  bool HasUndefInput = false;
3922  for (Value *Incoming : PN->incoming_values()) {
3923  // If the incoming value is the phi node itself, it can safely be skipped.
3924  if (Incoming == PN) continue;
3925  if (isa<UndefValue>(Incoming)) {
3926  // Remember that we saw an undef value, but otherwise ignore them.
3927  HasUndefInput = true;
3928  continue;
3929  }
3930  if (CommonValue && Incoming != CommonValue)
3931  return nullptr; // Not the same, bail out.
3932  CommonValue = Incoming;
3933  }
3934 
3935  // If CommonValue is null then all of the incoming values were either undef or
3936  // equal to the phi node itself.
3937  if (!CommonValue)
3938  return UndefValue::get(PN->getType());
3939 
3940  // If we have a PHI node like phi(X, undef, X), where X is defined by some
3941  // instruction, we cannot return X as the result of the PHI node unless it
3942  // dominates the PHI block.
3943  if (HasUndefInput)
3944  return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
3945 
3946  return CommonValue;
3947 }
3948 
3949 static Value *SimplifyCastInst(unsigned CastOpc, Value *Op,
3950  Type *Ty, const SimplifyQuery &Q, unsigned MaxRecurse) {
3951  if (auto *C = dyn_cast<Constant>(Op))
3952  return ConstantFoldCastOperand(CastOpc, C, Ty, Q.DL);
3953 
3954  if (auto *CI = dyn_cast<CastInst>(Op)) {
3955  auto *Src = CI->getOperand(0);
3956  Type *SrcTy = Src->getType();
3957  Type *MidTy = CI->getType();
3958  Type *DstTy = Ty;
3959  if (Src->getType() == Ty) {
3960  auto FirstOp = static_cast<Instruction::CastOps>(CI->getOpcode());
3961  auto SecondOp = static_cast<Instruction::CastOps>(CastOpc);
3962  Type *SrcIntPtrTy =
3963  SrcTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(SrcTy) : nullptr;
3964  Type *MidIntPtrTy =
3965  MidTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(MidTy) : nullptr;
3966  Type *DstIntPtrTy =
3967  DstTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(DstTy) : nullptr;
3968  if (CastInst::isEliminableCastPair(FirstOp, SecondOp, SrcTy, MidTy, DstTy,
3969  SrcIntPtrTy, MidIntPtrTy,
3970  DstIntPtrTy) == Instruction::BitCast)
3971  return Src;
3972  }
3973  }
3974 
3975  // bitcast x -> x
3976  if (CastOpc == Instruction::BitCast)
3977  if (Op->getType() == Ty)
3978  return Op;
3979 
3980  return nullptr;
3981 }
3982 
3983 Value *llvm::SimplifyCastInst(unsigned CastOpc, Value *Op, Type *Ty,
3984  const SimplifyQuery &Q) {
3985  return ::SimplifyCastInst(CastOpc, Op, Ty, Q, RecursionLimit);
3986 }
3987 
3988 /// For the given destination element of a shuffle, peek through shuffles to
3989 /// match a root vector source operand that contains that element in the same
3990 /// vector lane (ie, the same mask index), so we can eliminate the shuffle(s).
3991 static Value *foldIdentityShuffles(int DestElt, Value *Op0, Value *Op1,
3992  int MaskVal, Value *RootVec,
3993  unsigned MaxRecurse) {
3994  if (!MaxRecurse--)
3995  return nullptr;
3996 
3997  // Bail out if any mask value is undefined. That kind of shuffle may be
3998  // simplified further based on demanded bits or other folds.
3999  if (MaskVal == -1)
4000  return nullptr;
4001 
4002  // The mask value chooses which source operand we need to look at next.
4003  int InVecNumElts = Op0->getType()->getVectorNumElements();
4004  int RootElt = MaskVal;
4005  Value *SourceOp = Op0;
4006  if (MaskVal >= InVecNumElts) {
4007  RootElt = MaskVal - InVecNumElts;
4008  SourceOp = Op1;
4009  }
4010 
4011  // If the source operand is a shuffle itself, look through it to find the
4012  // matching root vector.
4013  if (auto *SourceShuf = dyn_cast<ShuffleVectorInst>(SourceOp)) {
4014  return foldIdentityShuffles(
4015  DestElt, SourceShuf->getOperand(0), SourceShuf->getOperand(1),
4016  SourceShuf->getMaskValue(RootElt), RootVec, MaxRecurse);
4017  }
4018 
4019  // TODO: Look through bitcasts? What if the bitcast changes the vector element
4020  // size?
4021 
4022  // The source operand is not a shuffle. Initialize the root vector value for
4023  // this shuffle if that has not been done yet.
4024  if (!RootVec)
4025  RootVec = SourceOp;
4026 
4027  // Give up as soon as a source operand does not match the existing root value.
4028  if (RootVec != SourceOp)
4029  return nullptr;
4030 
4031  // The element must be coming from the same lane in the source vector
4032  // (although it may have crossed lanes in intermediate shuffles).
4033  if (RootElt != DestElt)
4034  return nullptr;
4035 
4036  return RootVec;
4037 }
4038 
4040  Type *RetTy, const SimplifyQuery &Q,
4041  unsigned MaxRecurse) {
4042  if (isa<UndefValue>(Mask))
4043  return UndefValue::get(RetTy);
4044 
4045  Type *InVecTy = Op0->getType();
4046  unsigned MaskNumElts = Mask->getType()->getVectorNumElements();
4047  unsigned InVecNumElts = InVecTy->getVectorNumElements();
4048 
4049  SmallVector<int, 32> Indices;
4050  ShuffleVectorInst::getShuffleMask(Mask, Indices);
4051  assert(MaskNumElts == Indices.size() &&
4052  "Size of Indices not same as number of mask elements?");
4053 
4054  // Canonicalization: If mask does not select elements from an input vector,
4055  // replace that input vector with undef.
4056  bool MaskSelects0 = false, MaskSelects1 = false;
4057  for (unsigned i = 0; i != MaskNumElts; ++i) {
4058  if (Indices[i] == -1)
4059  continue;
4060  if ((unsigned)Indices[i] < InVecNumElts)
4061  MaskSelects0 = true;
4062  else
4063  MaskSelects1 = true;
4064  }
4065  if (!MaskSelects0)
4066  Op0 = UndefValue::get(InVecTy);
4067  if (!MaskSelects1)
4068  Op1 = UndefValue::get(InVecTy);
4069 
4070  auto *Op0Const = dyn_cast<Constant>(Op0);
4071  auto *Op1Const = dyn_cast<Constant>(Op1);
4072 
4073  // If all operands are constant, constant fold the shuffle.
4074  if (Op0Const && Op1Const)
4075  return ConstantFoldShuffleVectorInstruction(Op0Const, Op1Const, Mask);
4076 
4077  // Canonicalization: if only one input vector is constant, it shall be the
4078  // second one.
4079  if (Op0Const && !Op1Const) {
4080  std::swap(Op0, Op1);
4081  ShuffleVectorInst::commuteShuffleMask(Indices, InVecNumElts);
4082  }
4083 
4084  // A shuffle of a splat is always the splat itself. Legal if the shuffle's
4085  // value type is same as the input vectors' type.
4086  if (auto *OpShuf = dyn_cast<ShuffleVectorInst>(Op0))
4087  if (isa<UndefValue>(Op1) && RetTy == InVecTy &&
4088  OpShuf->getMask()->getSplatValue())
4089  return Op0;
4090 
4091  // Don't fold a shuffle with undef mask elements. This may get folded in a
4092  // better way using demanded bits or other analysis.
4093  // TODO: Should we allow this?
4094  if (find(Indices, -1) != Indices.end())
4095  return nullptr;
4096 
4097  // Check if every element of this shuffle can be mapped back to the
4098  // corresponding element of a single root vector. If so, we don't need this
4099  // shuffle. This handles simple identity shuffles as well as chains of
4100  // shuffles that may widen/narrow and/or move elements across lanes and back.
4101  Value *RootVec = nullptr;
4102  for (unsigned i = 0; i != MaskNumElts; ++i) {
4103  // Note that recursion is limited for each vector element, so if any element
4104  // exceeds the limit, this will fail to simplify.
4105  RootVec =
4106  foldIdentityShuffles(i, Op0, Op1, Indices[i], RootVec, MaxRecurse);
4107 
4108  // We can't replace a widening/narrowing shuffle with one of its operands.
4109  if (!RootVec || RootVec->getType() != RetTy)
4110  return nullptr;
4111  }
4112  return RootVec;
4113 }
4114 
4115 /// Given operands for a ShuffleVectorInst, fold the result or return null.
4117  Type *RetTy, const SimplifyQuery &Q) {
4118  return ::SimplifyShuffleVectorInst(Op0, Op1, Mask, RetTy, Q, RecursionLimit);
4119 }
4120 
4121 /// Given operands for an FAdd, see if we can fold the result. If not, this
4122 /// returns null.
4124  const SimplifyQuery &Q, unsigned MaxRecurse) {
4125  if (Constant *C = foldOrCommuteConstant(Instruction::FAdd, Op0, Op1, Q))
4126  return C;
4127 
4128  // fadd X, -0 ==> X
4129  if (match(Op1, m_NegZero()))
4130  return Op0;
4131 
4132  // fadd X, 0 ==> X, when we know X is not -0
4133  if (match(Op1, m_Zero()) &&
4134  (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
4135  return Op0;
4136 
4137  // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
4138  // where nnan and ninf have to occur at least once somewhere in this
4139  // expression
4140  Value *SubOp = nullptr;
4141  if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
4142  SubOp = Op1;
4143  else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
4144  SubOp = Op0;
4145  if (SubOp) {
4146  Instruction *FSub = cast<Instruction>(SubOp);
4147  if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
4148  (FMF.noInfs() || FSub->hasNoInfs()))
4149  return Constant::getNullValue(Op0->getType());
4150  }
4151 
4152  return nullptr;
4153 }
4154 
4155 /// Given operands for an FSub, see if we can fold the result. If not, this
4156 /// returns null.
4158  const SimplifyQuery &Q, unsigned MaxRecurse) {
4159  if (Constant *C = foldOrCommuteConstant(Instruction::FSub, Op0, Op1, Q))
4160  return C;
4161 
4162  // fsub X, 0 ==> X
4163  if (match(Op1, m_Zero()))
4164  return Op0;
4165 
4166  // fsub X, -0 ==> X, when we know X is not -0
4167  if (match(Op1, m_NegZero()) &&
4168  (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
4169  return Op0;
4170 
4171  // fsub -0.0, (fsub -0.0, X) ==> X
4172  Value *X;
4173  if (match(Op0, m_NegZero()) && match(Op1, m_FSub(m_NegZero(), m_Value(X))))
4174  return X;
4175 
4176  // fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored.
4177  if (FMF.noSignedZeros() && match(Op0, m_AnyZero()) &&
4178  match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
4179  return X;
4180 
4181  // fsub nnan x, x ==> 0.0
4182  if (FMF.noNaNs() && Op0 == Op1)
4183  return Constant::getNullValue(Op0->getType());
4184 
4185  return nullptr;
4186 }
4187 
4188 /// Given the operands for an FMul, see if we can fold the result
4190  const SimplifyQuery &Q, unsigned MaxRecurse) {
4191  if (Constant *C = foldOrCommuteConstant(Instruction::FMul, Op0, Op1, Q))
4192  return C;
4193 
4194  // fmul X, 1.0 ==> X
4195  if (match(Op1, m_FPOne()))
4196  return Op0;
4197 
4198  // fmul nnan nsz X, 0 ==> 0
4199  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
4200  return Op1;
4201 
4202  return nullptr;
4203 }
4204 
4206  const SimplifyQuery &Q) {
4207  return ::SimplifyFAddInst(Op0, Op1, FMF, Q, RecursionLimit);
4208 }
4209 
4210 
4212  const SimplifyQuery &Q) {
4213  return ::SimplifyFSubInst(Op0, Op1, FMF, Q, RecursionLimit);
4214 }
4215 
4217  const SimplifyQuery &Q) {
4218  return ::SimplifyFMulInst(Op0, Op1, FMF, Q, RecursionLimit);
4219 }
4220 
4222  const SimplifyQuery &Q, unsigned) {
4223  if (Constant *C = foldOrCommuteConstant(Instruction::FDiv, Op0, Op1, Q))
4224  return C;
4225 
4226  // undef / X -> undef (the undef could be a snan).
4227  if (match(Op0, m_Undef()))
4228  return Op0;
4229 
4230  // X / undef -> undef
4231  if (match(Op1, m_Undef()))
4232  return Op1;
4233 
4234  // X / 1.0 -> X
4235  if (match(Op1, m_FPOne()))
4236  return Op0;
4237 
4238  // 0 / X -> 0
4239  // Requires that NaNs are off (X could be zero) and signed zeroes are
4240  // ignored (X could be positive or negative, so the output sign is unknown).
4241  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZero()))
4242  return Op0;
4243 
4244  if (FMF.noNaNs()) {
4245  // X / X -> 1.0 is legal when NaNs are ignored.
4246  if (Op0 == Op1)
4247  return ConstantFP::get(Op0->getType(), 1.0);
4248 
4249  // -X / X -> -1.0 and
4250  // X / -X -> -1.0 are legal when NaNs are ignored.
4251  // We can ignore signed zeros because +-0.0/+-0.0 is NaN and ignored.
4252  if ((BinaryOperator::isFNeg(Op0, /*IgnoreZeroSign=*/true) &&
4253  BinaryOperator::getFNegArgument(Op0) == Op1) ||
4254  (BinaryOperator::isFNeg(Op1, /*IgnoreZeroSign=*/true) &&
4255  BinaryOperator::getFNegArgument(Op1) == Op0))
4256  return ConstantFP::get(Op0->getType(), -1.0);
4257  }
4258 
4259  return nullptr;
4260 }
4261 
4263  const SimplifyQuery &Q) {
4264  return ::SimplifyFDivInst(Op0, Op1, FMF, Q, RecursionLimit);
4265 }
4266 
4268  const SimplifyQuery &Q, unsigned) {
4269  if (Constant *C = foldOrCommuteConstant(Instruction::FRem, Op0, Op1, Q))
4270  return C;
4271 
4272  // undef % X -> undef (the undef could be a snan).
4273  if (match(Op0, m_Undef()))
4274  return Op0;
4275 
4276  // X % undef -> undef
4277  if (match(Op1, m_Undef()))
4278  return Op1;
4279 
4280  // 0 % X -> 0
4281  // Requires that NaNs are off (X could be zero) and signed zeroes are
4282  // ignored (X could be positive or negative, so the output sign is unknown).
4283  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZero()))
4284  return Op0;
4285 
4286  return nullptr;
4287 }
4288 
4290  const SimplifyQuery &Q) {
4291  return ::SimplifyFRemInst(Op0, Op1, FMF, Q, RecursionLimit);
4292 }
4293 
4294 //=== Helper functions for higher up the class hierarchy.
4295 
4296 /// Given operands for a BinaryOperator, see if we can fold the result.
4297 /// If not, this returns null.
4298 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4299  const SimplifyQuery &Q, unsigned MaxRecurse) {
4300  switch (Opcode) {
4301  case Instruction::Add:
4302  return SimplifyAddInst(LHS, RHS, false, false, Q, MaxRecurse);
4303  case Instruction::Sub:
4304  return SimplifySubInst(LHS, RHS, false, false, Q, MaxRecurse);
4305  case Instruction::Mul:
4306  return SimplifyMulInst(LHS, RHS, Q, MaxRecurse);
4307  case Instruction::SDiv:
4308  return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
4309  case Instruction::UDiv:
4310  return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
4311  case Instruction::SRem:
4312  return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
4313  case Instruction::URem:
4314  return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
4315  case Instruction::Shl:
4316  return SimplifyShlInst(LHS, RHS, false, false, Q, MaxRecurse);
4317  case Instruction::LShr:
4318  return SimplifyLShrInst(LHS, RHS, false, Q, MaxRecurse);
4319  case Instruction::AShr:
4320  return SimplifyAShrInst(LHS, RHS, false, Q, MaxRecurse);
4321  case Instruction::And:
4322  return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
4323  case Instruction::Or:
4324  return SimplifyOrInst(LHS, RHS, Q, MaxRecurse);
4325  case Instruction::Xor:
4326  return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
4327  case Instruction::FAdd:
4328  return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4329  case Instruction::FSub:
4330  return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4331  case Instruction::FMul:
4332  return SimplifyFMulInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4333  case Instruction::FDiv:
4334  return SimplifyFDivInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4335  case Instruction::FRem:
4336  return SimplifyFRemInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4337  default:
4338  llvm_unreachable("Unexpected opcode");
4339  }
4340 }
4341 
4342 /// Given operands for a BinaryOperator, see if we can fold the result.
4343 /// If not, this returns null.
4344 /// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the
4345 /// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp.
4346 static Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4347  const FastMathFlags &FMF, const SimplifyQuery &Q,
4348  unsigned MaxRecurse) {
4349  switch (Opcode) {
4350  case Instruction::FAdd:
4351  return SimplifyFAddInst(LHS, RHS, FMF, Q, MaxRecurse);
4352  case Instruction::FSub:
4353  return SimplifyFSubInst(LHS, RHS, FMF, Q, MaxRecurse);
4354  case Instruction::FMul:
4355  return SimplifyFMulInst(LHS, RHS, FMF, Q, MaxRecurse);
4356  case Instruction::FDiv:
4357  return SimplifyFDivInst(LHS, RHS, FMF, Q, MaxRecurse);
4358  default:
4359  return SimplifyBinOp(Opcode, LHS, RHS, Q, MaxRecurse);
4360  }
4361 }
4362 
4363 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4364  const SimplifyQuery &Q) {
4365  return ::SimplifyBinOp(Opcode, LHS, RHS, Q, RecursionLimit);
4366 }
4367 
4368 Value *llvm::SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4369  FastMathFlags FMF, const SimplifyQuery &Q) {
4370  return ::SimplifyFPBinOp(Opcode, LHS, RHS, FMF, Q, RecursionLimit);
4371 }
4372 
4373 /// Given operands for a CmpInst, see if we can fold the result.
4374 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
4375  const SimplifyQuery &Q, unsigned MaxRecurse) {
4377  return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
4378  return SimplifyFCmpInst(Predicate, LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4379 }
4380 
4381 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
4382  const SimplifyQuery &Q) {
4383  return ::SimplifyCmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
4384 }
4385 
4387  switch (ID) {
4388  default: return false;
4389 
4390  // Unary idempotent: f(f(x)) = f(x)
4391  case Intrinsic::fabs:
4392  case Intrinsic::floor:
4393  case Intrinsic::ceil:
4394  case Intrinsic::trunc:
4395  case Intrinsic::rint:
4396  case Intrinsic::nearbyint:
4397  case Intrinsic::round:
4398  case Intrinsic::canonicalize:
4399  return true;
4400  }
4401 }
4402 
4404  const DataLayout &DL) {
4405  GlobalValue *PtrSym;
4406  APInt PtrOffset;
4407  if (!IsConstantOffsetFromGlobal(Ptr, PtrSym, PtrOffset, DL))
4408  return nullptr;
4409 
4410  Type *Int8PtrTy = Type::getInt8PtrTy(Ptr->getContext());
4412  Type *Int32PtrTy = Int32Ty->getPointerTo();
4413  Type *Int64Ty = Type::getInt64Ty(Ptr->getContext());
4414 
4415  auto *OffsetConstInt = dyn_cast<ConstantInt>(Offset);
4416  if (!OffsetConstInt || OffsetConstInt->getType()->getBitWidth() > 64)
4417  return nullptr;
4418 
4419  uint64_t OffsetInt = OffsetConstInt->getSExtValue();
4420  if (OffsetInt % 4 != 0)
4421  return nullptr;
4422 
4424  Int32Ty, ConstantExpr::getBitCast(Ptr, Int32PtrTy),
4425  ConstantInt::get(Int64Ty, OffsetInt / 4));
4426  Constant *Loaded = ConstantFoldLoadFromConstPtr(C, Int32Ty, DL);
4427  if (!Loaded)
4428  return nullptr;
4429 
4430  auto *LoadedCE = dyn_cast<ConstantExpr>(Loaded);
4431  if (!LoadedCE)
4432  return nullptr;
4433 
4434  if (LoadedCE->getOpcode() == Instruction::Trunc) {
4435  LoadedCE = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4436  if (!LoadedCE)
4437  return nullptr;
4438  }
4439 
4440  if (LoadedCE->getOpcode() != Instruction::Sub)
4441  return nullptr;
4442 
4443  auto *LoadedLHS = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4444  if (!LoadedLHS || LoadedLHS->getOpcode() != Instruction::PtrToInt)
4445  return nullptr;
4446  auto *LoadedLHSPtr = LoadedLHS->getOperand(0);
4447 
4448  Constant *LoadedRHS = LoadedCE->getOperand(1);
4449  GlobalValue *LoadedRHSSym;
4450  APInt LoadedRHSOffset;
4451  if (!IsConstantOffsetFromGlobal(LoadedRHS, LoadedRHSSym, LoadedRHSOffset,
4452  DL) ||
4453  PtrSym != LoadedRHSSym || PtrOffset != LoadedRHSOffset)
4454  return nullptr;
4455 
4456  return ConstantExpr::getBitCast(LoadedLHSPtr, Int8PtrTy);
4457 }
4458 
4460  auto *ConstMask = dyn_cast<Constant>(Mask);
4461  if (!ConstMask)
4462  return false;
4463  if (ConstMask->isNullValue() || isa<UndefValue>(ConstMask))
4464  return true;
4465  for (unsigned I = 0, E = ConstMask->getType()->getVectorNumElements(); I != E;
4466  ++I) {
4467  if (auto *MaskElt = ConstMask->getAggregateElement(I))
4468  if (MaskElt->isNullValue() || isa<UndefValue>(MaskElt))
4469  continue;
4470  return false;
4471  }
4472  return true;
4473 }
4474 
4475 template <typename IterTy>
4476 static Value *SimplifyIntrinsic(Function *F, IterTy ArgBegin, IterTy ArgEnd,
4477  const SimplifyQuery &Q, unsigned MaxRecurse) {
4478  Intrinsic::ID IID = F->getIntrinsicID();
4479  unsigned NumOperands = std::distance(ArgBegin, ArgEnd);
4480 
4481  // Unary Ops
4482  if (NumOperands == 1) {
4483  // Perform idempotent optimizations
4484  if (IsIdempotent(IID)) {
4485  if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin)) {
4486  if (II->getIntrinsicID() == IID)
4487  return II;
4488  }
4489  }
4490 
4491  switch (IID) {
4492  case Intrinsic::fabs: {
4493  if (SignBitMustBeZero(*ArgBegin, Q.TLI))
4494  return *ArgBegin;
4495  return nullptr;
4496  }
4497  default:
4498  return nullptr;
4499  }
4500  }
4501 
4502  // Binary Ops
4503  if (NumOperands == 2) {
4504  Value *LHS = *ArgBegin;
4505  Value *RHS = *(ArgBegin + 1);
4506  Type *ReturnType = F->getReturnType();
4507 
4508  switch (IID) {
4509  case Intrinsic::usub_with_overflow:
4510  case Intrinsic::ssub_with_overflow: {
4511  // X - X -> { 0, false }
4512  if (LHS == RHS)
4513  return Constant::getNullValue(ReturnType);
4514 
4515  // X - undef -> undef
4516  // undef - X -> undef
4517  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
4518  return UndefValue::get(ReturnType);
4519 
4520  return nullptr;
4521  }
4522  case Intrinsic::uadd_with_overflow:
4523  case Intrinsic::sadd_with_overflow: {
4524  // X + undef -> undef
4525  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
4526  return UndefValue::get(ReturnType);
4527 
4528  return nullptr;
4529  }
4530  case Intrinsic::umul_with_overflow:
4531  case Intrinsic::smul_with_overflow: {
4532  // 0 * X -> { 0, false }
4533  // X * 0 -> { 0, false }
4534  if (match(LHS, m_Zero()) || match(RHS, m_Zero()))
4535  return Constant::getNullValue(ReturnType);
4536 
4537  // undef * X -> { 0, false }
4538  // X * undef -> { 0, false }
4539  if (match(LHS, m_Undef()) || match(RHS, m_Undef()))
4540  return Constant::getNullValue(ReturnType);
4541 
4542  return nullptr;
4543  }
4544  case Intrinsic::load_relative: {
4545  Constant *C0 = dyn_cast<Constant>(LHS);
4546  Constant *C1 = dyn_cast<Constant>(RHS);
4547  if (C0 && C1)
4548  return SimplifyRelativeLoad(C0, C1, Q.DL);
4549  return nullptr;
4550  }
4551  default:
4552  return nullptr;
4553  }
4554  }
4555 
4556  // Simplify calls to llvm.masked.load.*
4557  switch (IID) {
4558  case Intrinsic::masked_load: {
4559  Value *MaskArg = ArgBegin[2];
4560  Value *PassthruArg = ArgBegin[3];
4561  // If the mask is all zeros or undef, the "passthru" argument is the result.
4562  if (maskIsAllZeroOrUndef(MaskArg))
4563  return PassthruArg;
4564  return nullptr;
4565  }
4566  default:
4567  return nullptr;
4568  }
4569 }
4570 
4571 template <typename IterTy>
4572 static Value *SimplifyCall(ImmutableCallSite CS, Value *V, IterTy ArgBegin,
4573  IterTy ArgEnd, const SimplifyQuery &Q,
4574  unsigned MaxRecurse) {
4575  Type *Ty = V->getType();
4576  if (PointerType *PTy = dyn_cast<PointerType>(Ty))
4577  Ty = PTy->getElementType();
4578  FunctionType *FTy = cast<FunctionType>(Ty);
4579 
4580  // call undef -> undef
4581  // call null -> undef
4582  if (isa<UndefValue>(V) || isa<ConstantPointerNull>(V))
4583  return UndefValue::get(FTy->getReturnType());
4584 
4585  Function *F = dyn_cast<Function>(V);
4586  if (!F)
4587  return nullptr;
4588 
4589  if (F->isIntrinsic())
4590  if (Value *Ret = SimplifyIntrinsic(F, ArgBegin, ArgEnd, Q, MaxRecurse))
4591  return Ret;
4592 
4593  if (!canConstantFoldCallTo(CS, F))
4594  return nullptr;
4595 
4596  SmallVector<Constant *, 4> ConstantArgs;
4597  ConstantArgs.reserve(ArgEnd - ArgBegin);
4598  for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
4599  Constant *C = dyn_cast<Constant>(*I);
4600  if (!C)
4601  return nullptr;
4602  ConstantArgs.push_back(C);
4603  }
4604 
4605  return ConstantFoldCall(CS, F, ConstantArgs, Q.TLI);
4606 }
4607 
4609  User::op_iterator ArgBegin, User::op_iterator ArgEnd,
4610  const SimplifyQuery &Q) {
4611  return ::SimplifyCall(CS, V, ArgBegin, ArgEnd, Q, RecursionLimit);
4612 }
4613 
4615  ArrayRef<Value *> Args, const SimplifyQuery &Q) {
4616  return ::SimplifyCall(CS, V, Args.begin(), Args.end(), Q, RecursionLimit);
4617 }
4618 
4619 /// See if we can compute a simplified version of this instruction.
4620 /// If not, this returns null.
4621 
4624  const SimplifyQuery Q = SQ.CxtI ? SQ : SQ.getWithInstruction(I);
4625  Value *Result;
4626 
4627  switch (I->getOpcode()) {
4628  default:
4629  Result = ConstantFoldInstruction(I, Q.DL, Q.TLI);
4630  break;
4631  case Instruction::FAdd:
4632  Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
4633  I->getFastMathFlags(), Q);
4634  break;
4635  case Instruction::Add:
4636  Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
4637  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4638  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4639  break;
4640  case Instruction::FSub:
4641  Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
4642  I->getFastMathFlags(), Q);
4643  break;
4644  case Instruction::Sub:
4645  Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
4646  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4647  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4648  break;
4649  case Instruction::FMul:
4650  Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
4651  I->getFastMathFlags(), Q);
4652  break;
4653  case Instruction::Mul:
4654  Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), Q);
4655  break;
4656  case Instruction::SDiv:
4657  Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), Q);
4658  break;
4659  case Instruction::UDiv:
4660  Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), Q);
4661  break;
4662  case Instruction::FDiv:
4663  Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1),
4664  I->getFastMathFlags(), Q);
4665  break;
4666  case Instruction::SRem:
4667  Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), Q);
4668  break;
4669  case Instruction::URem:
4670  Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), Q);
4671  break;
4672  case Instruction::FRem:
4673  Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1),
4674  I->getFastMathFlags(), Q);
4675  break;
4676  case Instruction::Shl:
4677  Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
4678  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4679  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4680  break;
4681  case Instruction::LShr:
4682  Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
4683  cast<BinaryOperator>(I)->isExact(), Q);
4684  break;
4685  case Instruction::AShr:
4686  Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
4687  cast<BinaryOperator>(I)->isExact(), Q);
4688  break;
4689  case Instruction::And:
4690  Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), Q);
4691  break;
4692  case Instruction::Or:
4693  Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), Q);
4694  break;
4695  case Instruction::Xor:
4696  Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), Q);
4697  break;
4698  case Instruction::ICmp:
4699  Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
4700  I->getOperand(0), I->getOperand(1), Q);
4701  break;
4702  case Instruction::FCmp:
4703  Result =
4704  SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(), I->getOperand(0),
4705  I->getOperand(1), I->getFastMathFlags(), Q);
4706  break;
4707  case Instruction::Select:
4708  Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
4709  I->getOperand(2), Q);
4710  break;
4711  case Instruction::GetElementPtr: {
4712  SmallVector<Value *, 8> Ops(I->op_begin(), I->op_end());
4713  Result = SimplifyGEPInst(cast<GetElementPtrInst>(I)->getSourceElementType(),
4714  Ops, Q);
4715  break;
4716  }
4717  case Instruction::InsertValue: {
4718  InsertValueInst *IV = cast<InsertValueInst>(I);
4721  IV->getIndices(), Q);
4722  break;
4723  }
4724  case Instruction::InsertElement: {
4725  auto *IE = cast<InsertElementInst>(I);
4726  Result = SimplifyInsertElementInst(IE->getOperand(0), IE->getOperand(1),
4727  IE->getOperand(2), Q);
4728  break;
4729  }
4730  case Instruction::ExtractValue: {
4731  auto *EVI = cast<ExtractValueInst>(I);
4732  Result = SimplifyExtractValueInst(EVI->getAggregateOperand(),
4733  EVI->getIndices(), Q);
4734  break;
4735  }
4736  case Instruction::ExtractElement: {
4737  auto *EEI = cast<ExtractElementInst>(I);
4738  Result = SimplifyExtractElementInst(EEI->getVectorOperand(),
4739  EEI->getIndexOperand(), Q);
4740  break;
4741  }
4742  case Instruction::ShuffleVector: {
4743  auto *SVI = cast<ShuffleVectorInst>(I);
4744  Result = SimplifyShuffleVectorInst(SVI->getOperand(0), SVI->getOperand(1),
4745  SVI->getMask(), SVI->getType(), Q);
4746  break;
4747  }
4748  case Instruction::PHI:
4749  Result = SimplifyPHINode(cast<PHINode>(I), Q);
4750  break;
4751  case Instruction::Call: {
4752  CallSite CS(cast<CallInst>(I));
4753  Result = SimplifyCall(CS, CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
4754  Q);
4755  break;
4756  }
4757 #define HANDLE_CAST_INST(num, opc, clas) case Instruction::opc:
4758 #include "llvm/IR/Instruction.def"
4759 #undef HANDLE_CAST_INST
4760  Result =
4761  SimplifyCastInst(I->getOpcode(), I->getOperand(0), I->getType(), Q);
4762  break;
4763  case Instruction::Alloca:
4764  // No simplifications for Alloca and it can't be constant folded.
4765  Result = nullptr;
4766  break;
4767  }
4768 
4769  // In general, it is possible for computeKnownBits to determine all bits in a
4770  // value even when the operands are not all constants.
4771  if (!Result && I->getType()->isIntOrIntVectorTy()) {
4772  KnownBits Known = computeKnownBits(I, Q.DL, /*Depth*/ 0, Q.AC, I, Q.DT, ORE);
4773  if (Known.isConstant())
4774  Result = ConstantInt::get(I->getType(), Known.getConstant());
4775  }
4776 
4777  /// If called on unreachable code, the above logic may report that the
4778  /// instruction simplified to itself. Make life easier for users by
4779  /// detecting that case here, returning a safe value instead.
4780  return Result == I ? UndefValue::get(I->getType()) : Result;
4781 }
4782 
4783 /// \brief Implementation of recursive simplification through an instruction's
4784 /// uses.
4785 ///
4786 /// This is the common implementation of the recursive simplification routines.
4787 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
4788 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
4789 /// instructions to process and attempt to simplify it using
4790 /// InstructionSimplify.
4791 ///
4792 /// This routine returns 'true' only when *it* simplifies something. The passed
4793 /// in simplified value does not count toward this.
4795  const TargetLibraryInfo *TLI,
4796  const DominatorTree *DT,
4797  AssumptionCache *AC) {
4798  bool Simplified = false;
4800  const DataLayout &DL = I->getModule()->getDataLayout();
4801 
4802  // If we have an explicit value to collapse to, do that round of the
4803  // simplification loop by hand initially.
4804  if (SimpleV) {
4805  for (User *U : I->users())
4806  if (U != I)
4807  Worklist.insert(cast<Instruction>(U));
4808 
4809  // Replace the instruction with its simplified value.
4810  I->replaceAllUsesWith(SimpleV);
4811 
4812  // Gracefully handle edge cases where the instruction is not wired into any
4813  // parent block.
4814  if (I->getParent() && !I->isEHPad() && !isa<TerminatorInst>(I) &&
4815  !I->mayHaveSideEffects())
4816  I->eraseFromParent();
4817  } else {
4818  Worklist.insert(I);
4819  }
4820 
4821  // Note that we must test the size on each iteration, the worklist can grow.
4822  for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
4823  I = Worklist[Idx];
4824 
4825  // See if this instruction simplifies.
4826  SimpleV = SimplifyInstruction(I, {DL, TLI, DT, AC});
4827  if (!SimpleV)
4828  continue;
4829 
4830  Simplified = true;
4831 
4832  // Stash away all the uses of the old instruction so we can check them for
4833  // recursive simplifications after a RAUW. This is cheaper than checking all
4834  // uses of To on the recursive step in most cases.
4835  for (User *U : I->users())
4836  Worklist.insert(cast<Instruction>(U));
4837 
4838  // Replace the instruction with its simplified value.
4839  I->replaceAllUsesWith(SimpleV);
4840 
4841  // Gracefully handle edge cases where the instruction is not wired into any
4842  // parent block.
4843  if (I->getParent() && !I->isEHPad() && !isa<TerminatorInst>(I) &&
4844  !I->mayHaveSideEffects())
4845  I->eraseFromParent();
4846  }
4847  return Simplified;
4848 }
4849 
4851  const TargetLibraryInfo *TLI,
4852  const DominatorTree *DT,
4853  AssumptionCache *AC) {
4854  return replaceAndRecursivelySimplifyImpl(I, nullptr, TLI, DT, AC);
4855 }
4856 
4858  const TargetLibraryInfo *TLI,
4859  const DominatorTree *DT,
4860  AssumptionCache *AC) {
4861  assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
4862  assert(SimpleV && "Must provide a simplified value.");
4863  return replaceAndRecursivelySimplifyImpl(I, SimpleV, TLI, DT, AC);
4864 }
4865 
4866 namespace llvm {
4869  auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
4871  auto *TLI = TLIWP ? &TLIWP->getTLI() : nullptr;
4873  auto *AC = ACWP ? &ACWP->getAssumptionCache(F) : nullptr;
4874  return {F.getParent()->getDataLayout(), TLI, DT, AC};
4875 }
4876 
4878  const DataLayout &DL) {
4879  return {DL, &AR.TLI, &AR.DT, &AR.AC};
4880 }
4881 
4882 template <class T, class... TArgs>
4884  Function &F) {
4885  auto *DT = AM.template getCachedResult<DominatorTreeAnalysis>(F);
4886  auto *TLI = AM.template getCachedResult<TargetLibraryAnalysis>(F);
4887  auto *AC = AM.template getCachedResult<AssumptionAnalysis>(F);
4888  return {F.getParent()->getDataLayout(), TLI, DT, AC};
4889 }
4891  Function &);
4892 }
Constant * ConstantFoldCastOperand(unsigned Opcode, Constant *C, Type *DestTy, const DataLayout &DL)
Attempt to constant fold a cast with the specified operand.
static Value * SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse)
Given operands for a URem, see if we can fold the result.
MaxMin_match< ICmpInst, LHS, RHS, umin_pred_ty > m_UMin(const LHS &L, const RHS &R)
APInt abs() const
Get the absolute value;.
Definition: APInt.h:1779
Pass interface - Implemented by all &#39;passes&#39;.
Definition: Pass.h:81