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() == 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 an FAdd, see if we can fold the result. If not, this
795 /// returns null.
797  const SimplifyQuery &Q, unsigned MaxRecurse) {
798  if (Constant *C = foldOrCommuteConstant(Instruction::FAdd, Op0, Op1, Q))
799  return C;
800 
801  // fadd X, -0 ==> X
802  if (match(Op1, m_NegZero()))
803  return Op0;
804 
805  // fadd X, 0 ==> X, when we know X is not -0
806  if (match(Op1, m_Zero()) &&
807  (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
808  return Op0;
809 
810  // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
811  // where nnan and ninf have to occur at least once somewhere in this
812  // expression
813  Value *SubOp = nullptr;
814  if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
815  SubOp = Op1;
816  else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
817  SubOp = Op0;
818  if (SubOp) {
819  Instruction *FSub = cast<Instruction>(SubOp);
820  if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
821  (FMF.noInfs() || FSub->hasNoInfs()))
822  return Constant::getNullValue(Op0->getType());
823  }
824 
825  return nullptr;
826 }
827 
828 /// Given operands for an FSub, see if we can fold the result. If not, this
829 /// returns null.
831  const SimplifyQuery &Q, unsigned MaxRecurse) {
832  if (Constant *C = foldOrCommuteConstant(Instruction::FSub, Op0, Op1, Q))
833  return C;
834 
835  // fsub X, 0 ==> X
836  if (match(Op1, m_Zero()))
837  return Op0;
838 
839  // fsub X, -0 ==> X, when we know X is not -0
840  if (match(Op1, m_NegZero()) &&
841  (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
842  return Op0;
843 
844  // fsub -0.0, (fsub -0.0, X) ==> X
845  Value *X;
846  if (match(Op0, m_NegZero()) && match(Op1, m_FSub(m_NegZero(), m_Value(X))))
847  return X;
848 
849  // fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored.
850  if (FMF.noSignedZeros() && match(Op0, m_AnyZero()) &&
851  match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
852  return X;
853 
854  // fsub nnan x, x ==> 0.0
855  if (FMF.noNaNs() && Op0 == Op1)
856  return Constant::getNullValue(Op0->getType());
857 
858  return nullptr;
859 }
860 
861 /// Given the operands for an FMul, see if we can fold the result
863  const SimplifyQuery &Q, unsigned MaxRecurse) {
864  if (Constant *C = foldOrCommuteConstant(Instruction::FMul, Op0, Op1, Q))
865  return C;
866 
867  // fmul X, 1.0 ==> X
868  if (match(Op1, m_FPOne()))
869  return Op0;
870 
871  // fmul nnan nsz X, 0 ==> 0
872  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
873  return Op1;
874 
875  return nullptr;
876 }
877 
878 /// Given operands for a Mul, see if we can fold the result.
879 /// If not, this returns null.
880 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
881  unsigned MaxRecurse) {
882  if (Constant *C = foldOrCommuteConstant(Instruction::Mul, Op0, Op1, Q))
883  return C;
884 
885  // X * undef -> 0
886  if (match(Op1, m_Undef()))
887  return Constant::getNullValue(Op0->getType());
888 
889  // X * 0 -> 0
890  if (match(Op1, m_Zero()))
891  return Op1;
892 
893  // X * 1 -> X
894  if (match(Op1, m_One()))
895  return Op0;
896 
897  // (X / Y) * Y -> X if the division is exact.
898  Value *X = nullptr;
899  if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
900  match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
901  return X;
902 
903  // i1 mul -> and.
904  if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
905  if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
906  return V;
907 
908  // Try some generic simplifications for associative operations.
909  if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
910  MaxRecurse))
911  return V;
912 
913  // Mul distributes over Add. Try some generic simplifications based on this.
914  if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
915  Q, MaxRecurse))
916  return V;
917 
918  // If the operation is with the result of a select instruction, check whether
919  // operating on either branch of the select always yields the same value.
920  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
921  if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
922  MaxRecurse))
923  return V;
924 
925  // If the operation is with the result of a phi instruction, check whether
926  // operating on all incoming values of the phi always yields the same value.
927  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
928  if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
929  MaxRecurse))
930  return V;
931 
932  return nullptr;
933 }
934 
936  const SimplifyQuery &Q) {
937  return ::SimplifyFAddInst(Op0, Op1, FMF, Q, RecursionLimit);
938 }
939 
940 
942  const SimplifyQuery &Q) {
943  return ::SimplifyFSubInst(Op0, Op1, FMF, Q, RecursionLimit);
944 }
945 
947  const SimplifyQuery &Q) {
948  return ::SimplifyFMulInst(Op0, Op1, FMF, Q, RecursionLimit);
949 }
950 
953 }
954 
955 /// Check for common or similar folds of integer division or integer remainder.
956 static Value *simplifyDivRem(Value *Op0, Value *Op1, bool IsDiv) {
957  Type *Ty = Op0->getType();
958 
959  // X / undef -> undef
960  // X % undef -> undef
961  if (match(Op1, m_Undef()))
962  return Op1;
963 
964  // X / 0 -> undef
965  // X % 0 -> undef
966  // We don't need to preserve faults!
967  if (match(Op1, m_Zero()))
968  return UndefValue::get(Ty);
969 
970  // If any element of a constant divisor vector is zero, the whole op is undef.
971  auto *Op1C = dyn_cast<Constant>(Op1);
972  if (Op1C && Ty->isVectorTy()) {
973  unsigned NumElts = Ty->getVectorNumElements();
974  for (unsigned i = 0; i != NumElts; ++i) {
975  Constant *Elt = Op1C->getAggregateElement(i);
976  if (Elt && Elt->isNullValue())
977  return UndefValue::get(Ty);
978  }
979  }
980 
981  // undef / X -> 0
982  // undef % X -> 0
983  if (match(Op0, m_Undef()))
984  return Constant::getNullValue(Ty);
985 
986  // 0 / X -> 0
987  // 0 % X -> 0
988  if (match(Op0, m_Zero()))
989  return Op0;
990 
991  // X / X -> 1
992  // X % X -> 0
993  if (Op0 == Op1)
994  return IsDiv ? ConstantInt::get(Ty, 1) : Constant::getNullValue(Ty);
995 
996  // X / 1 -> X
997  // X % 1 -> 0
998  // If this is a boolean op (single-bit element type), we can't have
999  // division-by-zero or remainder-by-zero, so assume the divisor is 1.
1000  if (match(Op1, m_One()) || Ty->isIntOrIntVectorTy(1))
1001  return IsDiv ? Op0 : Constant::getNullValue(Ty);
1002 
1003  return nullptr;
1004 }
1005 
1006 /// Given operands for an SDiv or UDiv, see if we can fold the result.
1007 /// If not, this returns null.
1009  const SimplifyQuery &Q, unsigned MaxRecurse) {
1010  if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1011  return C;
1012 
1013  if (Value *V = simplifyDivRem(Op0, Op1, true))
1014  return V;
1015 
1016  bool isSigned = Opcode == Instruction::SDiv;
1017 
1018  // (X * Y) / Y -> X if the multiplication does not overflow.
1019  Value *X = nullptr, *Y = nullptr;
1020  if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
1021  if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
1022  OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
1023  // If the Mul knows it does not overflow, then we are good to go.
1024  if ((isSigned && Mul->hasNoSignedWrap()) ||
1025  (!isSigned && Mul->hasNoUnsignedWrap()))
1026  return X;
1027  // If X has the form X = A / Y then X * Y cannot overflow.
1028  if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
1029  if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
1030  return X;
1031  }
1032 
1033  // (X rem Y) / Y -> 0
1034  if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1035  (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1036  return Constant::getNullValue(Op0->getType());
1037 
1038  // (X /u C1) /u C2 -> 0 if C1 * C2 overflow
1039  ConstantInt *C1, *C2;
1040  if (!isSigned && match(Op0, m_UDiv(m_Value(X), m_ConstantInt(C1))) &&
1041  match(Op1, m_ConstantInt(C2))) {
1042  bool Overflow;
1043  (void)C1->getValue().umul_ov(C2->getValue(), Overflow);
1044  if (Overflow)
1045  return Constant::getNullValue(Op0->getType());
1046  }
1047 
1048  // If the operation is with the result of a select instruction, check whether
1049  // operating on either branch of the select always yields the same value.
1050  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1051  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1052  return V;
1053 
1054  // If the operation is with the result of a phi instruction, check whether
1055  // operating on all incoming values of the phi always yields the same value.
1056  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1057  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1058  return V;
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  if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse))
1068  return V;
1069 
1070  return nullptr;
1071 }
1072 
1075 }
1076 
1077 /// Given operands for a UDiv, see if we can fold the result.
1078 /// If not, this returns null.
1079 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1080  unsigned MaxRecurse) {
1081  if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
1082  return V;
1083 
1084  // udiv %V, C -> 0 if %V < C
1085  if (MaxRecurse) {
1086  if (Constant *C = dyn_cast_or_null<Constant>(SimplifyICmpInst(
1087  ICmpInst::ICMP_ULT, Op0, Op1, Q, MaxRecurse - 1))) {
1088  if (C->isAllOnesValue()) {
1089  return Constant::getNullValue(Op0->getType());
1090  }
1091  }
1092  }
1093 
1094  return nullptr;
1095 }
1096 
1099 }
1100 
1102  const SimplifyQuery &Q, unsigned) {
1103  if (Constant *C = foldOrCommuteConstant(Instruction::FDiv, Op0, Op1, Q))
1104  return C;
1105 
1106  // undef / X -> undef (the undef could be a snan).
1107  if (match(Op0, m_Undef()))
1108  return Op0;
1109 
1110  // X / undef -> undef
1111  if (match(Op1, m_Undef()))
1112  return Op1;
1113 
1114  // X / 1.0 -> X
1115  if (match(Op1, m_FPOne()))
1116  return Op0;
1117 
1118  // 0 / X -> 0
1119  // Requires that NaNs are off (X could be zero) and signed zeroes are
1120  // ignored (X could be positive or negative, so the output sign is unknown).
1121  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZero()))
1122  return Op0;
1123 
1124  if (FMF.noNaNs()) {
1125  // X / X -> 1.0 is legal when NaNs are ignored.
1126  if (Op0 == Op1)
1127  return ConstantFP::get(Op0->getType(), 1.0);
1128 
1129  // -X / X -> -1.0 and
1130  // X / -X -> -1.0 are legal when NaNs are ignored.
1131  // We can ignore signed zeros because +-0.0/+-0.0 is NaN and ignored.
1132  if ((BinaryOperator::isFNeg(Op0, /*IgnoreZeroSign=*/true) &&
1133  BinaryOperator::getFNegArgument(Op0) == Op1) ||
1134  (BinaryOperator::isFNeg(Op1, /*IgnoreZeroSign=*/true) &&
1135  BinaryOperator::getFNegArgument(Op1) == Op0))
1136  return ConstantFP::get(Op0->getType(), -1.0);
1137  }
1138 
1139  return nullptr;
1140 }
1141 
1143  const SimplifyQuery &Q) {
1144  return ::SimplifyFDivInst(Op0, Op1, FMF, Q, RecursionLimit);
1145 }
1146 
1147 /// Given operands for an SRem or URem, see if we can fold the result.
1148 /// If not, this returns null.
1150  const SimplifyQuery &Q, unsigned MaxRecurse) {
1151  if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1152  return C;
1153 
1154  if (Value *V = simplifyDivRem(Op0, Op1, false))
1155  return V;
1156 
1157  // (X % Y) % Y -> X % Y
1158  if ((Opcode == Instruction::SRem &&
1159  match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1160  (Opcode == Instruction::URem &&
1161  match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1162  return Op0;
1163 
1164  // If the operation is with the result of a select instruction, check whether
1165  // operating on either branch of the select always yields the same value.
1166  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1167  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1168  return V;
1169 
1170  // If the operation is with the result of a phi instruction, check whether
1171  // operating on all incoming values of the phi always yields the same value.
1172  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1173  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1174  return V;
1175 
1176  return nullptr;
1177 }
1178 
1179 /// Given operands for an SRem, see if we can fold the result.
1180 /// If not, this returns null.
1181 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1182  unsigned MaxRecurse) {
1183  if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
1184  return V;
1185 
1186  return nullptr;
1187 }
1188 
1191 }
1192 
1193 /// Given operands for a URem, see if we can fold the result.
1194 /// If not, this returns null.
1195 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1196  unsigned MaxRecurse) {
1197  if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
1198  return V;
1199 
1200  // urem %V, C -> %V if %V < C
1201  if (MaxRecurse) {
1202  if (Constant *C = dyn_cast_or_null<Constant>(SimplifyICmpInst(
1203  ICmpInst::ICMP_ULT, Op0, Op1, Q, MaxRecurse - 1))) {
1204  if (C->isAllOnesValue()) {
1205  return Op0;
1206  }
1207  }
1208  }
1209 
1210  return nullptr;
1211 }
1212 
1215 }
1216 
1218  const SimplifyQuery &Q, unsigned) {
1219  if (Constant *C = foldOrCommuteConstant(Instruction::FRem, Op0, Op1, Q))
1220  return C;
1221 
1222  // undef % X -> undef (the undef could be a snan).
1223  if (match(Op0, m_Undef()))
1224  return Op0;
1225 
1226  // X % undef -> undef
1227  if (match(Op1, m_Undef()))
1228  return Op1;
1229 
1230  // 0 % X -> 0
1231  // Requires that NaNs are off (X could be zero) and signed zeroes are
1232  // ignored (X could be positive or negative, so the output sign is unknown).
1233  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZero()))
1234  return Op0;
1235 
1236  return nullptr;
1237 }
1238 
1240  const SimplifyQuery &Q) {
1241  return ::SimplifyFRemInst(Op0, Op1, FMF, Q, RecursionLimit);
1242 }
1243 
1244 /// Returns true if a shift by \c Amount always yields undef.
1245 static bool isUndefShift(Value *Amount) {
1246  Constant *C = dyn_cast<Constant>(Amount);
1247  if (!C)
1248  return false;
1249 
1250  // X shift by undef -> undef because it may shift by the bitwidth.
1251  if (isa<UndefValue>(C))
1252  return true;
1253 
1254  // Shifting by the bitwidth or more is undefined.
1255  if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
1256  if (CI->getValue().getLimitedValue() >=
1257  CI->getType()->getScalarSizeInBits())
1258  return true;
1259 
1260  // If all lanes of a vector shift are undefined the whole shift is.
1261  if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) {
1262  for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I)
1264  return false;
1265  return true;
1266  }
1267 
1268  return false;
1269 }
1270 
1271 /// Given operands for an Shl, LShr or AShr, see if we can fold the result.
1272 /// If not, this returns null.
1274  Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse) {
1275  if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1276  return C;
1277 
1278  // 0 shift by X -> 0
1279  if (match(Op0, m_Zero()))
1280  return Op0;
1281 
1282  // X shift by 0 -> X
1283  if (match(Op1, m_Zero()))
1284  return Op0;
1285 
1286  // Fold undefined shifts.
1287  if (isUndefShift(Op1))
1288  return UndefValue::get(Op0->getType());
1289 
1290  // If the operation is with the result of a select instruction, check whether
1291  // operating on either branch of the select always yields the same value.
1292  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1293  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1294  return V;
1295 
1296  // If the operation is with the result of a phi instruction, check whether
1297  // operating on all incoming values of the phi always yields the same value.
1298  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1299  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1300  return V;
1301 
1302  // If any bits in the shift amount make that value greater than or equal to
1303  // the number of bits in the type, the shift is undefined.
1304  KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1305  if (Known.One.getLimitedValue() >= Known.getBitWidth())
1306  return UndefValue::get(Op0->getType());
1307 
1308  // If all valid bits in the shift amount are known zero, the first operand is
1309  // unchanged.
1310  unsigned NumValidShiftBits = Log2_32_Ceil(Known.getBitWidth());
1311  if (Known.countMinTrailingZeros() >= NumValidShiftBits)
1312  return Op0;
1313 
1314  return nullptr;
1315 }
1316 
1317 /// \brief Given operands for an Shl, LShr or AShr, see if we can
1318 /// fold the result. If not, this returns null.
1320  Value *Op1, bool isExact, const SimplifyQuery &Q,
1321  unsigned MaxRecurse) {
1322  if (Value *V = SimplifyShift(Opcode, Op0, Op1, Q, MaxRecurse))
1323  return V;
1324 
1325  // X >> X -> 0
1326  if (Op0 == Op1)
1327  return Constant::getNullValue(Op0->getType());
1328 
1329  // undef >> X -> 0
1330  // undef >> X -> undef (if it's exact)
1331  if (match(Op0, m_Undef()))
1332  return isExact ? Op0 : Constant::getNullValue(Op0->getType());
1333 
1334  // The low bit cannot be shifted out of an exact shift if it is set.
1335  if (isExact) {
1336  KnownBits Op0Known = computeKnownBits(Op0, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT);
1337  if (Op0Known.One[0])
1338  return Op0;
1339  }
1340 
1341  return nullptr;
1342 }
1343 
1344 /// Given operands for an Shl, see if we can fold the result.
1345 /// If not, this returns null.
1346 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1347  const SimplifyQuery &Q, unsigned MaxRecurse) {
1348  if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1349  return V;
1350 
1351  // undef << X -> 0
1352  // undef << X -> undef if (if it's NSW/NUW)
1353  if (match(Op0, m_Undef()))
1354  return isNSW || isNUW ? Op0 : Constant::getNullValue(Op0->getType());
1355 
1356  // (X >> A) << A -> X
1357  Value *X;
1358  if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1359  return X;
1360  return nullptr;
1361 }
1362 
1363 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1364  const SimplifyQuery &Q) {
1365  return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit);
1366 }
1367 
1368 /// Given operands for an LShr, see if we can fold the result.
1369 /// If not, this returns null.
1370 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1371  const SimplifyQuery &Q, unsigned MaxRecurse) {
1372  if (Value *V = SimplifyRightShift(Instruction::LShr, Op0, Op1, isExact, Q,
1373  MaxRecurse))
1374  return V;
1375 
1376  // (X << A) >> A -> X
1377  Value *X;
1378  if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1))))
1379  return X;
1380 
1381  return nullptr;
1382 }
1383 
1384 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1385  const SimplifyQuery &Q) {
1386  return ::SimplifyLShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1387 }
1388 
1389 /// Given operands for an AShr, see if we can fold the result.
1390 /// If not, this returns null.
1391 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1392  const SimplifyQuery &Q, unsigned MaxRecurse) {
1393  if (Value *V = SimplifyRightShift(Instruction::AShr, Op0, Op1, isExact, Q,
1394  MaxRecurse))
1395  return V;
1396 
1397  // all ones >>a X -> all ones
1398  if (match(Op0, m_AllOnes()))
1399  return Op0;
1400 
1401  // (X << A) >> A -> X
1402  Value *X;
1403  if (match(Op0, m_NSWShl(m_Value(X), m_Specific(Op1))))
1404  return X;
1405 
1406  // Arithmetic shifting an all-sign-bit value is a no-op.
1407  unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1408  if (NumSignBits == Op0->getType()->getScalarSizeInBits())
1409  return Op0;
1410 
1411  return nullptr;
1412 }
1413 
1414 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1415  const SimplifyQuery &Q) {
1416  return ::SimplifyAShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1417 }
1418 
1419 /// Commuted variants are assumed to be handled by calling this function again
1420 /// with the parameters swapped.
1422  ICmpInst *UnsignedICmp, bool IsAnd) {
1423  Value *X, *Y;
1424 
1425  ICmpInst::Predicate EqPred;
1426  if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) ||
1427  !ICmpInst::isEquality(EqPred))
1428  return nullptr;
1429 
1430  ICmpInst::Predicate UnsignedPred;
1431  if (match(UnsignedICmp, m_ICmp(UnsignedPred, m_Value(X), m_Specific(Y))) &&
1432  ICmpInst::isUnsigned(UnsignedPred))
1433  ;
1434  else if (match(UnsignedICmp,
1435  m_ICmp(UnsignedPred, m_Value(Y), m_Specific(X))) &&
1436  ICmpInst::isUnsigned(UnsignedPred))
1437  UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred);
1438  else
1439  return nullptr;
1440 
1441  // X < Y && Y != 0 --> X < Y
1442  // X < Y || Y != 0 --> Y != 0
1443  if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE)
1444  return IsAnd ? UnsignedICmp : ZeroICmp;
1445 
1446  // X >= Y || Y != 0 --> true
1447  // X >= Y || Y == 0 --> X >= Y
1448  if (UnsignedPred == ICmpInst::ICMP_UGE && !IsAnd) {
1449  if (EqPred == ICmpInst::ICMP_NE)
1450  return getTrue(UnsignedICmp->getType());
1451  return UnsignedICmp;
1452  }
1453 
1454  // X < Y && Y == 0 --> false
1455  if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
1456  IsAnd)
1457  return getFalse(UnsignedICmp->getType());
1458 
1459  return nullptr;
1460 }
1461 
1462 /// Commuted variants are assumed to be handled by calling this function again
1463 /// with the parameters swapped.
1465  ICmpInst::Predicate Pred0, Pred1;
1466  Value *A ,*B;
1467  if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
1468  !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
1469  return nullptr;
1470 
1471  // We have (icmp Pred0, A, B) & (icmp Pred1, A, B).
1472  // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1473  // can eliminate Op1 from this 'and'.
1474  if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
1475  return Op0;
1476 
1477  // Check for any combination of predicates that are guaranteed to be disjoint.
1478  if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
1479  (Pred0 == ICmpInst::ICMP_EQ && ICmpInst::isFalseWhenEqual(Pred1)) ||
1480  (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT) ||
1481  (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT))
1482  return getFalse(Op0->getType());
1483 
1484  return nullptr;
1485 }
1486 
1487 /// Commuted variants are assumed to be handled by calling this function again
1488 /// with the parameters swapped.
1490  ICmpInst::Predicate Pred0, Pred1;
1491  Value *A ,*B;
1492  if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
1493  !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
1494  return nullptr;
1495 
1496  // We have (icmp Pred0, A, B) | (icmp Pred1, A, B).
1497  // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1498  // can eliminate Op0 from this 'or'.
1499  if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
1500  return Op1;
1501 
1502  // Check for any combination of predicates that cover the entire range of
1503  // possibilities.
1504  if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
1505  (Pred0 == ICmpInst::ICMP_NE && ICmpInst::isTrueWhenEqual(Pred1)) ||
1506  (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGE) ||
1507  (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGE))
1508  return getTrue(Op0->getType());
1509 
1510  return nullptr;
1511 }
1512 
1513 /// Test if a pair of compares with a shared operand and 2 constants has an
1514 /// empty set intersection, full set union, or if one compare is a superset of
1515 /// the other.
1517  bool IsAnd) {
1518  // Look for this pattern: {and/or} (icmp X, C0), (icmp X, C1)).
1519  if (Cmp0->getOperand(0) != Cmp1->getOperand(0))
1520  return nullptr;
1521 
1522  const APInt *C0, *C1;
1523  if (!match(Cmp0->getOperand(1), m_APInt(C0)) ||
1524  !match(Cmp1->getOperand(1), m_APInt(C1)))
1525  return nullptr;
1526 
1527  auto Range0 = ConstantRange::makeExactICmpRegion(Cmp0->getPredicate(), *C0);
1528  auto Range1 = ConstantRange::makeExactICmpRegion(Cmp1->getPredicate(), *C1);
1529 
1530  // For and-of-compares, check if the intersection is empty:
1531  // (icmp X, C0) && (icmp X, C1) --> empty set --> false
1532  if (IsAnd && Range0.intersectWith(Range1).isEmptySet())
1533  return getFalse(Cmp0->getType());
1534 
1535  // For or-of-compares, check if the union is full:
1536  // (icmp X, C0) || (icmp X, C1) --> full set --> true
1537  if (!IsAnd && Range0.unionWith(Range1).isFullSet())
1538  return getTrue(Cmp0->getType());
1539 
1540  // Is one range a superset of the other?
1541  // If this is and-of-compares, take the smaller set:
1542  // (icmp sgt X, 4) && (icmp sgt X, 42) --> icmp sgt X, 42
1543  // If this is or-of-compares, take the larger set:
1544  // (icmp sgt X, 4) || (icmp sgt X, 42) --> icmp sgt X, 4
1545  if (Range0.contains(Range1))
1546  return IsAnd ? Cmp1 : Cmp0;
1547  if (Range1.contains(Range0))
1548  return IsAnd ? Cmp0 : Cmp1;
1549 
1550  return nullptr;
1551 }
1552 
1554  // (icmp (add V, C0), C1) & (icmp V, C0)
1555  ICmpInst::Predicate Pred0, Pred1;
1556  const APInt *C0, *C1;
1557  Value *V;
1558  if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
1559  return nullptr;
1560 
1561  if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
1562  return nullptr;
1563 
1564  auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1565  if (AddInst->getOperand(1) != Op1->getOperand(1))
1566  return nullptr;
1567 
1568  Type *ITy = Op0->getType();
1569  bool isNSW = AddInst->hasNoSignedWrap();
1570  bool isNUW = AddInst->hasNoUnsignedWrap();
1571 
1572  const APInt Delta = *C1 - *C0;
1573  if (C0->isStrictlyPositive()) {
1574  if (Delta == 2) {
1575  if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
1576  return getFalse(ITy);
1577  if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1578  return getFalse(ITy);
1579  }
1580  if (Delta == 1) {
1581  if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
1582  return getFalse(ITy);
1583  if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1584  return getFalse(ITy);
1585  }
1586  }
1587  if (C0->getBoolValue() && isNUW) {
1588  if (Delta == 2)
1589  if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
1590  return getFalse(ITy);
1591  if (Delta == 1)
1592  if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
1593  return getFalse(ITy);
1594  }
1595 
1596  return nullptr;
1597 }
1598 
1600  if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/true))
1601  return X;
1602  if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/true))
1603  return X;
1604 
1605  if (Value *X = simplifyAndOfICmpsWithSameOperands(Op0, Op1))
1606  return X;
1607  if (Value *X = simplifyAndOfICmpsWithSameOperands(Op1, Op0))
1608  return X;
1609 
1610  if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, true))
1611  return X;
1612 
1613  if (Value *X = simplifyAndOfICmpsWithAdd(Op0, Op1))
1614  return X;
1615  if (Value *X = simplifyAndOfICmpsWithAdd(Op1, Op0))
1616  return X;
1617 
1618  return nullptr;
1619 }
1620 
1622  // (icmp (add V, C0), C1) | (icmp V, C0)
1623  ICmpInst::Predicate Pred0, Pred1;
1624  const APInt *C0, *C1;
1625  Value *V;
1626  if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
1627  return nullptr;
1628 
1629  if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
1630  return nullptr;
1631 
1632  auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1633  if (AddInst->getOperand(1) != Op1->getOperand(1))
1634  return nullptr;
1635 
1636  Type *ITy = Op0->getType();
1637  bool isNSW = AddInst->hasNoSignedWrap();
1638  bool isNUW = AddInst->hasNoUnsignedWrap();
1639 
1640  const APInt Delta = *C1 - *C0;
1641  if (C0->isStrictlyPositive()) {
1642  if (Delta == 2) {
1643  if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE)
1644  return getTrue(ITy);
1645  if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1646  return getTrue(ITy);
1647  }
1648  if (Delta == 1) {
1649  if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE)
1650  return getTrue(ITy);
1651  if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1652  return getTrue(ITy);
1653  }
1654  }
1655  if (C0->getBoolValue() && isNUW) {
1656  if (Delta == 2)
1657  if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE)
1658  return getTrue(ITy);
1659  if (Delta == 1)
1660  if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE)
1661  return getTrue(ITy);
1662  }
1663 
1664  return nullptr;
1665 }
1666 
1668  if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/false))
1669  return X;
1670  if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/false))
1671  return X;
1672 
1673  if (Value *X = simplifyOrOfICmpsWithSameOperands(Op0, Op1))
1674  return X;
1675  if (Value *X = simplifyOrOfICmpsWithSameOperands(Op1, Op0))
1676  return X;
1677 
1678  if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, false))
1679  return X;
1680 
1681  if (Value *X = simplifyOrOfICmpsWithAdd(Op0, Op1))
1682  return X;
1683  if (Value *X = simplifyOrOfICmpsWithAdd(Op1, Op0))
1684  return X;
1685 
1686  return nullptr;
1687 }
1688 
1689 static Value *simplifyAndOrOfICmps(Value *Op0, Value *Op1, bool IsAnd) {
1690  // Look through casts of the 'and' operands to find compares.
1691  auto *Cast0 = dyn_cast<CastInst>(Op0);
1692  auto *Cast1 = dyn_cast<CastInst>(Op1);
1693  if (Cast0 && Cast1 && Cast0->getOpcode() == Cast1->getOpcode() &&
1694  Cast0->getSrcTy() == Cast1->getSrcTy()) {
1695  Op0 = Cast0->getOperand(0);
1696  Op1 = Cast1->getOperand(0);
1697  }
1698 
1699  auto *Cmp0 = dyn_cast<ICmpInst>(Op0);
1700  auto *Cmp1 = dyn_cast<ICmpInst>(Op1);
1701  if (!Cmp0 || !Cmp1)
1702  return nullptr;
1703 
1704  Value *V =
1705  IsAnd ? simplifyAndOfICmps(Cmp0, Cmp1) : simplifyOrOfICmps(Cmp0, Cmp1);
1706  if (!V)
1707  return nullptr;
1708  if (!Cast0)
1709  return V;
1710 
1711  // If we looked through casts, we can only handle a constant simplification
1712  // because we are not allowed to create a cast instruction here.
1713  if (auto *C = dyn_cast<Constant>(V))
1714  return ConstantExpr::getCast(Cast0->getOpcode(), C, Cast0->getType());
1715 
1716  return nullptr;
1717 }
1718 
1719 /// Given operands for an And, see if we can fold the result.
1720 /// If not, this returns null.
1721 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1722  unsigned MaxRecurse) {
1723  if (Constant *C = foldOrCommuteConstant(Instruction::And, Op0, Op1, Q))
1724  return C;
1725 
1726  // X & undef -> 0
1727  if (match(Op1, m_Undef()))
1728  return Constant::getNullValue(Op0->getType());
1729 
1730  // X & X = X
1731  if (Op0 == Op1)
1732  return Op0;
1733 
1734  // X & 0 = 0
1735  if (match(Op1, m_Zero()))
1736  return Op1;
1737 
1738  // X & -1 = X
1739  if (match(Op1, m_AllOnes()))
1740  return Op0;
1741 
1742  // A & ~A = ~A & A = 0
1743  if (match(Op0, m_Not(m_Specific(Op1))) ||
1744  match(Op1, m_Not(m_Specific(Op0))))
1745  return Constant::getNullValue(Op0->getType());
1746 
1747  // (A | ?) & A = A
1748  if (match(Op0, m_c_Or(m_Specific(Op1), m_Value())))
1749  return Op1;
1750 
1751  // A & (A | ?) = A
1752  if (match(Op1, m_c_Or(m_Specific(Op0), m_Value())))
1753  return Op0;
1754 
1755  // A mask that only clears known zeros of a shifted value is a no-op.
1756  Value *X;
1757  const APInt *Mask;
1758  const APInt *ShAmt;
1759  if (match(Op1, m_APInt(Mask))) {
1760  // If all bits in the inverted and shifted mask are clear:
1761  // and (shl X, ShAmt), Mask --> shl X, ShAmt
1762  if (match(Op0, m_Shl(m_Value(X), m_APInt(ShAmt))) &&
1763  (~(*Mask)).lshr(*ShAmt).isNullValue())
1764  return Op0;
1765 
1766  // If all bits in the inverted and shifted mask are clear:
1767  // and (lshr X, ShAmt), Mask --> lshr X, ShAmt
1768  if (match(Op0, m_LShr(m_Value(X), m_APInt(ShAmt))) &&
1769  (~(*Mask)).shl(*ShAmt).isNullValue())
1770  return Op0;
1771  }
1772 
1773  // A & (-A) = A if A is a power of two or zero.
1774  if (match(Op0, m_Neg(m_Specific(Op1))) ||
1775  match(Op1, m_Neg(m_Specific(Op0)))) {
1776  if (isKnownToBeAPowerOfTwo(Op0, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1777  Q.DT))
1778  return Op0;
1779  if (isKnownToBeAPowerOfTwo(Op1, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1780  Q.DT))
1781  return Op1;
1782  }
1783 
1784  if (Value *V = simplifyAndOrOfICmps(Op0, Op1, true))
1785  return V;
1786 
1787  // Try some generic simplifications for associative operations.
1788  if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1789  MaxRecurse))
1790  return V;
1791 
1792  // And distributes over Or. Try some generic simplifications based on this.
1793  if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1794  Q, MaxRecurse))
1795  return V;
1796 
1797  // And distributes over Xor. Try some generic simplifications based on this.
1798  if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1799  Q, MaxRecurse))
1800  return V;
1801 
1802  // If the operation is with the result of a select instruction, check whether
1803  // operating on either branch of the select always yields the same value.
1804  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1805  if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1806  MaxRecurse))
1807  return V;
1808 
1809  // If the operation is with the result of a phi instruction, check whether
1810  // operating on all incoming values of the phi always yields the same value.
1811  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1812  if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1813  MaxRecurse))
1814  return V;
1815 
1816  return nullptr;
1817 }
1818 
1821 }
1822 
1823 /// Given operands for an Or, see if we can fold the result.
1824 /// If not, this returns null.
1825 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1826  unsigned MaxRecurse) {
1827  if (Constant *C = foldOrCommuteConstant(Instruction::Or, Op0, Op1, Q))
1828  return C;
1829 
1830  // X | undef -> -1
1831  if (match(Op1, m_Undef()))
1832  return Constant::getAllOnesValue(Op0->getType());
1833 
1834  // X | X = X
1835  if (Op0 == Op1)
1836  return Op0;
1837 
1838  // X | 0 = X
1839  if (match(Op1, m_Zero()))
1840  return Op0;
1841 
1842  // X | -1 = -1
1843  if (match(Op1, m_AllOnes()))
1844  return Op1;
1845 
1846  // A | ~A = ~A | A = -1
1847  if (match(Op0, m_Not(m_Specific(Op1))) ||
1848  match(Op1, m_Not(m_Specific(Op0))))
1849  return Constant::getAllOnesValue(Op0->getType());
1850 
1851  // (A & ?) | A = A
1852  if (match(Op0, m_c_And(m_Specific(Op1), m_Value())))
1853  return Op1;
1854 
1855  // A | (A & ?) = A
1856  if (match(Op1, m_c_And(m_Specific(Op0), m_Value())))
1857  return Op0;
1858 
1859  // ~(A & ?) | A = -1
1860  if (match(Op0, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
1861  return Constant::getAllOnesValue(Op1->getType());
1862 
1863  // A | ~(A & ?) = -1
1864  if (match(Op1, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
1865  return Constant::getAllOnesValue(Op0->getType());
1866 
1867  Value *A, *B;
1868  // (A & ~B) | (A ^ B) -> (A ^ B)
1869  // (~B & A) | (A ^ B) -> (A ^ B)
1870  // (A & ~B) | (B ^ A) -> (B ^ A)
1871  // (~B & A) | (B ^ A) -> (B ^ A)
1872  if (match(Op1, m_Xor(m_Value(A), m_Value(B))) &&
1873  (match(Op0, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
1874  match(Op0, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
1875  return Op1;
1876 
1877  // Commute the 'or' operands.
1878  // (A ^ B) | (A & ~B) -> (A ^ B)
1879  // (A ^ B) | (~B & A) -> (A ^ B)
1880  // (B ^ A) | (A & ~B) -> (B ^ A)
1881  // (B ^ A) | (~B & A) -> (B ^ A)
1882  if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
1883  (match(Op1, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
1884  match(Op1, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
1885  return Op0;
1886 
1887  // (A & B) | (~A ^ B) -> (~A ^ B)
1888  // (B & A) | (~A ^ B) -> (~A ^ B)
1889  // (A & B) | (B ^ ~A) -> (B ^ ~A)
1890  // (B & A) | (B ^ ~A) -> (B ^ ~A)
1891  if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1892  (match(Op1, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
1893  match(Op1, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
1894  return Op1;
1895 
1896  // (~A ^ B) | (A & B) -> (~A ^ B)
1897  // (~A ^ B) | (B & A) -> (~A ^ B)
1898  // (B ^ ~A) | (A & B) -> (B ^ ~A)
1899  // (B ^ ~A) | (B & A) -> (B ^ ~A)
1900  if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1901  (match(Op0, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
1902  match(Op0, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
1903  return Op0;
1904 
1905  if (Value *V = simplifyAndOrOfICmps(Op0, Op1, false))
1906  return V;
1907 
1908  // Try some generic simplifications for associative operations.
1909  if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1910  MaxRecurse))
1911  return V;
1912 
1913  // Or distributes over And. Try some generic simplifications based on this.
1914  if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1915  MaxRecurse))
1916  return V;
1917 
1918  // If the operation is with the result of a select instruction, check whether
1919  // operating on either branch of the select always yields the same value.
1920  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1921  if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1922  MaxRecurse))
1923  return V;
1924 
1925  // (A & C1)|(B & C2)
1926  const APInt *C1, *C2;
1927  if (match(Op0, m_And(m_Value(A), m_APInt(C1))) &&
1928  match(Op1, m_And(m_Value(B), m_APInt(C2)))) {
1929  if (*C1 == ~*C2) {
1930  // (A & C1)|(B & C2)
1931  // If we have: ((V + N) & C1) | (V & C2)
1932  // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
1933  // replace with V+N.
1934  Value *N;
1935  if (C2->isMask() && // C2 == 0+1+
1936  match(A, m_c_Add(m_Specific(B), m_Value(N)))) {
1937  // Add commutes, try both ways.
1938  if (MaskedValueIsZero(N, *C2, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1939  return A;
1940  }
1941  // Or commutes, try both ways.
1942  if (C1->isMask() &&
1943  match(B, m_c_Add(m_Specific(A), m_Value(N)))) {
1944  // Add commutes, try both ways.
1945  if (MaskedValueIsZero(N, *C1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1946  return B;
1947  }
1948  }
1949  }
1950 
1951  // If the operation is with the result of a phi instruction, check whether
1952  // operating on all incoming values of the phi always yields the same value.
1953  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1954  if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1955  return V;
1956 
1957  return nullptr;
1958 }
1959 
1962 }
1963 
1964 /// Given operands for a Xor, see if we can fold the result.
1965 /// If not, this returns null.
1966 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1967  unsigned MaxRecurse) {
1968  if (Constant *C = foldOrCommuteConstant(Instruction::Xor, Op0, Op1, Q))
1969  return C;
1970 
1971  // A ^ undef -> undef
1972  if (match(Op1, m_Undef()))
1973  return Op1;
1974 
1975  // A ^ 0 = A
1976  if (match(Op1, m_Zero()))
1977  return Op0;
1978 
1979  // A ^ A = 0
1980  if (Op0 == Op1)
1981  return Constant::getNullValue(Op0->getType());
1982 
1983  // A ^ ~A = ~A ^ A = -1
1984  if (match(Op0, m_Not(m_Specific(Op1))) ||
1985  match(Op1, m_Not(m_Specific(Op0))))
1986  return Constant::getAllOnesValue(Op0->getType());
1987 
1988  // Try some generic simplifications for associative operations.
1989  if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1990  MaxRecurse))
1991  return V;
1992 
1993  // Threading Xor over selects and phi nodes is pointless, so don't bother.
1994  // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1995  // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1996  // only if B and C are equal. If B and C are equal then (since we assume
1997  // that operands have already been simplified) "select(cond, B, C)" should
1998  // have been simplified to the common value of B and C already. Analysing
1999  // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
2000  // for threading over phi nodes.
2001 
2002  return nullptr;
2003 }
2004 
2007 }
2008 
2009 
2011  return CmpInst::makeCmpResultType(Op->getType());
2012 }
2013 
2014 /// Rummage around inside V looking for something equivalent to the comparison
2015 /// "LHS Pred RHS". Return such a value if found, otherwise return null.
2016 /// Helper function for analyzing max/min idioms.
2018  Value *LHS, Value *RHS) {
2020  if (!SI)
2021  return nullptr;
2022  CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
2023  if (!Cmp)
2024  return nullptr;
2025  Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
2026  if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
2027  return Cmp;
2028  if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
2029  LHS == CmpRHS && RHS == CmpLHS)
2030  return Cmp;
2031  return nullptr;
2032 }
2033 
2034 // A significant optimization not implemented here is assuming that alloca
2035 // addresses are not equal to incoming argument values. They don't *alias*,
2036 // as we say, but that doesn't mean they aren't equal, so we take a
2037 // conservative approach.
2038 //
2039 // This is inspired in part by C++11 5.10p1:
2040 // "Two pointers of the same type compare equal if and only if they are both
2041 // null, both point to the same function, or both represent the same
2042 // address."
2043 //
2044 // This is pretty permissive.
2045 //
2046 // It's also partly due to C11 6.5.9p6:
2047 // "Two pointers compare equal if and only if both are null pointers, both are
2048 // pointers to the same object (including a pointer to an object and a
2049 // subobject at its beginning) or function, both are pointers to one past the
2050 // last element of the same array object, or one is a pointer to one past the
2051 // end of one array object and the other is a pointer to the start of a
2052 // different array object that happens to immediately follow the first array
2053 // object in the address space.)
2054 //
2055 // C11's version is more restrictive, however there's no reason why an argument
2056 // couldn't be a one-past-the-end value for a stack object in the caller and be
2057 // equal to the beginning of a stack object in the callee.
2058 //
2059 // If the C and C++ standards are ever made sufficiently restrictive in this
2060 // area, it may be possible to update LLVM's semantics accordingly and reinstate
2061 // this optimization.
2062 static Constant *
2064  const DominatorTree *DT, CmpInst::Predicate Pred,
2065  const Instruction *CxtI, Value *LHS, Value *RHS) {
2066  // First, skip past any trivial no-ops.
2067  LHS = LHS->stripPointerCasts();
2068  RHS = RHS->stripPointerCasts();
2069 
2070  // A non-null pointer is not equal to a null pointer.
2071  if (llvm::isKnownNonNull(LHS) && isa<ConstantPointerNull>(RHS) &&
2072  (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
2073  return ConstantInt::get(GetCompareTy(LHS),
2074  !CmpInst::isTrueWhenEqual(Pred));
2075 
2076  // We can only fold certain predicates on pointer comparisons.
2077  switch (Pred) {
2078  default:
2079  return nullptr;
2080 
2081  // Equality comaprisons are easy to fold.
2082  case CmpInst::ICMP_EQ:
2083  case CmpInst::ICMP_NE:
2084  break;
2085 
2086  // We can only handle unsigned relational comparisons because 'inbounds' on
2087  // a GEP only protects against unsigned wrapping.
2088  case CmpInst::ICMP_UGT:
2089  case CmpInst::ICMP_UGE:
2090  case CmpInst::ICMP_ULT:
2091  case CmpInst::ICMP_ULE:
2092  // However, we have to switch them to their signed variants to handle
2093  // negative indices from the base pointer.
2094  Pred = ICmpInst::getSignedPredicate(Pred);
2095  break;
2096  }
2097 
2098  // Strip off any constant offsets so that we can reason about them.
2099  // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
2100  // here and compare base addresses like AliasAnalysis does, however there are
2101  // numerous hazards. AliasAnalysis and its utilities rely on special rules
2102  // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
2103  // doesn't need to guarantee pointer inequality when it says NoAlias.
2104  Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
2105  Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
2106 
2107  // If LHS and RHS are related via constant offsets to the same base
2108  // value, we can replace it with an icmp which just compares the offsets.
2109  if (LHS == RHS)
2110  return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
2111 
2112  // Various optimizations for (in)equality comparisons.
2113  if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
2114  // Different non-empty allocations that exist at the same time have
2115  // different addresses (if the program can tell). Global variables always
2116  // exist, so they always exist during the lifetime of each other and all
2117  // allocas. Two different allocas usually have different addresses...
2118  //
2119  // However, if there's an @llvm.stackrestore dynamically in between two
2120  // allocas, they may have the same address. It's tempting to reduce the
2121  // scope of the problem by only looking at *static* allocas here. That would
2122  // cover the majority of allocas while significantly reducing the likelihood
2123  // of having an @llvm.stackrestore pop up in the middle. However, it's not
2124  // actually impossible for an @llvm.stackrestore to pop up in the middle of
2125  // an entry block. Also, if we have a block that's not attached to a
2126  // function, we can't tell if it's "static" under the current definition.
2127  // Theoretically, this problem could be fixed by creating a new kind of
2128  // instruction kind specifically for static allocas. Such a new instruction
2129  // could be required to be at the top of the entry block, thus preventing it
2130  // from being subject to a @llvm.stackrestore. Instcombine could even
2131  // convert regular allocas into these special allocas. It'd be nifty.
2132  // However, until then, this problem remains open.
2133  //
2134  // So, we'll assume that two non-empty allocas have different addresses
2135  // for now.
2136  //
2137  // With all that, if the offsets are within the bounds of their allocations
2138  // (and not one-past-the-end! so we can't use inbounds!), and their
2139  // allocations aren't the same, the pointers are not equal.
2140  //
2141  // Note that it's not necessary to check for LHS being a global variable
2142  // address, due to canonicalization and constant folding.
2143  if (isa<AllocaInst>(LHS) &&
2144  (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
2145  ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
2146  ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
2147  uint64_t LHSSize, RHSSize;
2148  if (LHSOffsetCI && RHSOffsetCI &&
2149  getObjectSize(LHS, LHSSize, DL, TLI) &&
2150  getObjectSize(RHS, RHSSize, DL, TLI)) {
2151  const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
2152  const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
2153  if (!LHSOffsetValue.isNegative() &&
2154  !RHSOffsetValue.isNegative() &&
2155  LHSOffsetValue.ult(LHSSize) &&
2156  RHSOffsetValue.ult(RHSSize)) {
2157  return ConstantInt::get(GetCompareTy(LHS),
2158  !CmpInst::isTrueWhenEqual(Pred));
2159  }
2160  }
2161 
2162  // Repeat the above check but this time without depending on DataLayout
2163  // or being able to compute a precise size.
2164  if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
2165  !cast<PointerType>(RHS->getType())->isEmptyTy() &&
2166  LHSOffset->isNullValue() &&
2167  RHSOffset->isNullValue())
2168  return ConstantInt::get(GetCompareTy(LHS),
2169  !CmpInst::isTrueWhenEqual(Pred));
2170  }
2171 
2172  // Even if an non-inbounds GEP occurs along the path we can still optimize
2173  // equality comparisons concerning the result. We avoid walking the whole
2174  // chain again by starting where the last calls to
2175  // stripAndComputeConstantOffsets left off and accumulate the offsets.
2176  Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
2177  Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
2178  if (LHS == RHS)
2179  return ConstantExpr::getICmp(Pred,
2180  ConstantExpr::getAdd(LHSOffset, LHSNoBound),
2181  ConstantExpr::getAdd(RHSOffset, RHSNoBound));
2182 
2183  // If one side of the equality comparison must come from a noalias call
2184  // (meaning a system memory allocation function), and the other side must
2185  // come from a pointer that cannot overlap with dynamically-allocated
2186  // memory within the lifetime of the current function (allocas, byval
2187  // arguments, globals), then determine the comparison result here.
2188  SmallVector<Value *, 8> LHSUObjs, RHSUObjs;
2189  GetUnderlyingObjects(LHS, LHSUObjs, DL);
2190  GetUnderlyingObjects(RHS, RHSUObjs, DL);
2191 
2192  // Is the set of underlying objects all noalias calls?
2193  auto IsNAC = [](ArrayRef<Value *> Objects) {
2194  return all_of(Objects, isNoAliasCall);
2195  };
2196 
2197  // Is the set of underlying objects all things which must be disjoint from
2198  // noalias calls. For allocas, we consider only static ones (dynamic
2199  // allocas might be transformed into calls to malloc not simultaneously
2200  // live with the compared-to allocation). For globals, we exclude symbols
2201  // that might be resolve lazily to symbols in another dynamically-loaded
2202  // library (and, thus, could be malloc'ed by the implementation).
2203  auto IsAllocDisjoint = [](ArrayRef<Value *> Objects) {
2204  return all_of(Objects, [](Value *V) {
2205  if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
2206  return AI->getParent() && AI->getFunction() && AI->isStaticAlloca();
2207  if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
2208  return (GV->hasLocalLinkage() || GV->hasHiddenVisibility() ||
2209  GV->hasProtectedVisibility() || GV->hasGlobalUnnamedAddr()) &&
2210  !GV->isThreadLocal();
2211  if (const Argument *A = dyn_cast<Argument>(V))
2212  return A->hasByValAttr();
2213  return false;
2214  });
2215  };
2216 
2217  if ((IsNAC(LHSUObjs) && IsAllocDisjoint(RHSUObjs)) ||
2218  (IsNAC(RHSUObjs) && IsAllocDisjoint(LHSUObjs)))
2219  return ConstantInt::get(GetCompareTy(LHS),
2220  !CmpInst::isTrueWhenEqual(Pred));
2221 
2222  // Fold comparisons for non-escaping pointer even if the allocation call
2223  // cannot be elided. We cannot fold malloc comparison to null. Also, the
2224  // dynamic allocation call could be either of the operands.
2225  Value *MI = nullptr;
2226  if (isAllocLikeFn(LHS, TLI) && llvm::isKnownNonNullAt(RHS, CxtI, DT))
2227  MI = LHS;
2228  else if (isAllocLikeFn(RHS, TLI) && llvm::isKnownNonNullAt(LHS, CxtI, DT))
2229  MI = RHS;
2230  // FIXME: We should also fold the compare when the pointer escapes, but the
2231  // compare dominates the pointer escape
2232  if (MI && !PointerMayBeCaptured(MI, true, true))
2233  return ConstantInt::get(GetCompareTy(LHS),
2235  }
2236 
2237  // Otherwise, fail.
2238  return nullptr;
2239 }
2240 
2241 /// Fold an icmp when its operands have i1 scalar type.
2243  Value *RHS, const SimplifyQuery &Q) {
2244  Type *ITy = GetCompareTy(LHS); // The return type.
2245  Type *OpTy = LHS->getType(); // The operand type.
2246  if (!OpTy->isIntOrIntVectorTy(1))
2247  return nullptr;
2248 
2249  // A boolean compared to true/false can be simplified in 14 out of the 20
2250  // (10 predicates * 2 constants) possible combinations. Cases not handled here
2251  // require a 'not' of the LHS, so those must be transformed in InstCombine.
2252  if (match(RHS, m_Zero())) {
2253  switch (Pred) {
2254  case CmpInst::ICMP_NE: // X != 0 -> X
2255  case CmpInst::ICMP_UGT: // X >u 0 -> X
2256  case CmpInst::ICMP_SLT: // X <s 0 -> X
2257  return LHS;
2258 
2259  case CmpInst::ICMP_ULT: // X <u 0 -> false
2260  case CmpInst::ICMP_SGT: // X >s 0 -> false
2261  return getFalse(ITy);
2262 
2263  case CmpInst::ICMP_UGE: // X >=u 0 -> true
2264  case CmpInst::ICMP_SLE: // X <=s 0 -> true
2265  return getTrue(ITy);
2266 
2267  default: break;
2268  }
2269  } else if (match(RHS, m_One())) {
2270  switch (Pred) {
2271  case CmpInst::ICMP_EQ: // X == 1 -> X
2272  case CmpInst::ICMP_UGE: // X >=u 1 -> X
2273  case CmpInst::ICMP_SLE: // X <=s -1 -> X
2274  return LHS;
2275 
2276  case CmpInst::ICMP_UGT: // X >u 1 -> false
2277  case CmpInst::ICMP_SLT: // X <s -1 -> false
2278  return getFalse(ITy);
2279 
2280  case CmpInst::ICMP_ULE: // X <=u 1 -> true
2281  case CmpInst::ICMP_SGE: // X >=s -1 -> true
2282  return getTrue(ITy);
2283 
2284  default: break;
2285  }
2286  }
2287 
2288  switch (Pred) {
2289  default:
2290  break;
2291  case ICmpInst::ICMP_UGE:
2292  if (isImpliedCondition(RHS, LHS, Q.DL).getValueOr(false))
2293  return getTrue(ITy);
2294  break;
2295  case ICmpInst::ICMP_SGE:
2296  /// For signed comparison, the values for an i1 are 0 and -1
2297  /// respectively. This maps into a truth table of:
2298  /// LHS | RHS | LHS >=s RHS | LHS implies RHS
2299  /// 0 | 0 | 1 (0 >= 0) | 1
2300  /// 0 | 1 | 1 (0 >= -1) | 1
2301  /// 1 | 0 | 0 (-1 >= 0) | 0
2302  /// 1 | 1 | 1 (-1 >= -1) | 1
2303  if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2304  return getTrue(ITy);
2305  break;
2306  case ICmpInst::ICMP_ULE:
2307  if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2308  return getTrue(ITy);
2309  break;
2310  }
2311 
2312  return nullptr;
2313 }
2314 
2315 /// Try hard to fold icmp with zero RHS because this is a common case.
2317  Value *RHS, const SimplifyQuery &Q) {
2318  if (!match(RHS, m_Zero()))
2319  return nullptr;
2320 
2321  Type *ITy = GetCompareTy(LHS); // The return type.
2322  switch (Pred) {
2323  default:
2324  llvm_unreachable("Unknown ICmp predicate!");
2325  case ICmpInst::ICMP_ULT:
2326  return getFalse(ITy);
2327  case ICmpInst::ICMP_UGE:
2328  return getTrue(ITy);
2329  case ICmpInst::ICMP_EQ:
2330  case ICmpInst::ICMP_ULE:
2331  if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2332  return getFalse(ITy);
2333  break;
2334  case ICmpInst::ICMP_NE:
2335  case ICmpInst::ICMP_UGT:
2336  if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2337  return getTrue(ITy);
2338  break;
2339  case ICmpInst::ICMP_SLT: {
2340  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2341  if (LHSKnown.isNegative())
2342  return getTrue(ITy);
2343  if (LHSKnown.isNonNegative())
2344  return getFalse(ITy);
2345  break;
2346  }
2347  case ICmpInst::ICMP_SLE: {
2348  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2349  if (LHSKnown.isNegative())
2350  return getTrue(ITy);
2351  if (LHSKnown.isNonNegative() &&
2352  isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2353  return getFalse(ITy);
2354  break;
2355  }
2356  case ICmpInst::ICMP_SGE: {
2357  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2358  if (LHSKnown.isNegative())
2359  return getFalse(ITy);
2360  if (LHSKnown.isNonNegative())
2361  return getTrue(ITy);
2362  break;
2363  }
2364  case ICmpInst::ICMP_SGT: {
2365  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2366  if (LHSKnown.isNegative())
2367  return getFalse(ITy);
2368  if (LHSKnown.isNonNegative() &&
2369  isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2370  return getTrue(ITy);
2371  break;
2372  }
2373  }
2374 
2375  return nullptr;
2376 }
2377 
2378 /// Many binary operators with a constant operand have an easy-to-compute
2379 /// range of outputs. This can be used to fold a comparison to always true or
2380 /// always false.
2381 static void setLimitsForBinOp(BinaryOperator &BO, APInt &Lower, APInt &Upper) {
2382  unsigned Width = Lower.getBitWidth();
2383  const APInt *C;
2384  switch (BO.getOpcode()) {
2385  case Instruction::Add:
2386  if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
2387  // FIXME: If we have both nuw and nsw, we should reduce the range further.
2388  if (BO.hasNoUnsignedWrap()) {
2389  // 'add nuw x, C' produces [C, UINT_MAX].
2390  Lower = *C;
2391  } else if (BO.hasNoSignedWrap()) {
2392  if (C->isNegative()) {
2393  // 'add nsw x, -C' produces [SINT_MIN, SINT_MAX - C].
2394  Lower = APInt::getSignedMinValue(Width);
2395  Upper = APInt::getSignedMaxValue(Width) + *C + 1;
2396  } else {
2397  // 'add nsw x, +C' produces [SINT_MIN + C, SINT_MAX].
2398  Lower = APInt::getSignedMinValue(Width) + *C;
2399  Upper = APInt::getSignedMaxValue(Width) + 1;
2400  }
2401  }
2402  }
2403  break;
2404 
2405  case Instruction::And:
2406  if (match(BO.getOperand(1), m_APInt(C)))
2407  // 'and x, C' produces [0, C].
2408  Upper = *C + 1;
2409  break;
2410 
2411  case Instruction::Or:
2412  if (match(BO.getOperand(1), m_APInt(C)))
2413  // 'or x, C' produces [C, UINT_MAX].
2414  Lower = *C;
2415  break;
2416 
2417  case Instruction::AShr:
2418  if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
2419  // 'ashr x, C' produces [INT_MIN >> C, INT_MAX >> C].
2420  Lower = APInt::getSignedMinValue(Width).ashr(*C);
2421  Upper = APInt::getSignedMaxValue(Width).ashr(*C) + 1;
2422  } else if (match(BO.getOperand(0), m_APInt(C))) {
2423  unsigned ShiftAmount = Width - 1;
2424  if (!C->isNullValue() && BO.isExact())
2425  ShiftAmount = C->countTrailingZeros();
2426  if (C->isNegative()) {
2427  // 'ashr C, x' produces [C, C >> (Width-1)]
2428  Lower = *C;
2429  Upper = C->ashr(ShiftAmount) + 1;
2430  } else {
2431  // 'ashr C, x' produces [C >> (Width-1), C]
2432  Lower = C->ashr(ShiftAmount);
2433  Upper = *C + 1;
2434  }
2435  }
2436  break;
2437 
2438  case Instruction::LShr:
2439  if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
2440  // 'lshr x, C' produces [0, UINT_MAX >> C].
2441  Upper = APInt::getAllOnesValue(Width).lshr(*C) + 1;
2442  } else if (match(BO.getOperand(0), m_APInt(C))) {
2443  // 'lshr C, x' produces [C >> (Width-1), C].
2444  unsigned ShiftAmount = Width - 1;
2445  if (!C->isNullValue() && BO.isExact())
2446  ShiftAmount = C->countTrailingZeros();
2447  Lower = C->lshr(ShiftAmount);
2448  Upper = *C + 1;
2449  }
2450  break;
2451 
2452  case Instruction::Shl:
2453  if (match(BO.getOperand(0), m_APInt(C))) {
2454  if (BO.hasNoUnsignedWrap()) {
2455  // 'shl nuw C, x' produces [C, C << CLZ(C)]
2456  Lower = *C;
2457  Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
2458  } else if (BO.hasNoSignedWrap()) { // TODO: What if both nuw+nsw?
2459  if (C->isNegative()) {
2460  // 'shl nsw C, x' produces [C << CLO(C)-1, C]
2461  unsigned ShiftAmount = C->countLeadingOnes() - 1;
2462  Lower = C->shl(ShiftAmount);
2463  Upper = *C + 1;
2464  } else {
2465  // 'shl nsw C, x' produces [C, C << CLZ(C)-1]
2466  unsigned ShiftAmount = C->countLeadingZeros() - 1;
2467  Lower = *C;
2468  Upper = C->shl(ShiftAmount) + 1;
2469  }
2470  }
2471  }
2472  break;
2473 
2474  case Instruction::SDiv:
2475  if (match(BO.getOperand(1), m_APInt(C))) {
2476  APInt IntMin = APInt::getSignedMinValue(Width);
2477  APInt IntMax = APInt::getSignedMaxValue(Width);
2478  if (C->isAllOnesValue()) {
2479  // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
2480  // where C != -1 and C != 0 and C != 1
2481  Lower = IntMin + 1;
2482  Upper = IntMax + 1;
2483  } else if (C->countLeadingZeros() < Width - 1) {
2484  // 'sdiv x, C' produces [INT_MIN / C, INT_MAX / C]
2485  // where C != -1 and C != 0 and C != 1
2486  Lower = IntMin.sdiv(*C);
2487  Upper = IntMax.sdiv(*C);
2488  if (Lower.sgt(Upper))
2489  std::swap(Lower, Upper);
2490  Upper = Upper + 1;
2491  assert(Upper != Lower && "Upper part of range has wrapped!");
2492  }
2493  } else if (match(BO.getOperand(0), m_APInt(C))) {
2494  if (C->isMinSignedValue()) {
2495  // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
2496  Lower = *C;
2497  Upper = Lower.lshr(1) + 1;
2498  } else {
2499  // 'sdiv C, x' produces [-|C|, |C|].
2500  Upper = C->abs() + 1;
2501  Lower = (-Upper) + 1;
2502  }
2503  }
2504  break;
2505 
2506  case Instruction::UDiv:
2507  if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
2508  // 'udiv x, C' produces [0, UINT_MAX / C].
2509  Upper = APInt::getMaxValue(Width).udiv(*C) + 1;
2510  } else if (match(BO.getOperand(0), m_APInt(C))) {
2511  // 'udiv C, x' produces [0, C].
2512  Upper = *C + 1;
2513  }
2514  break;
2515 
2516  case Instruction::SRem:
2517  if (match(BO.getOperand(1), m_APInt(C))) {
2518  // 'srem x, C' produces (-|C|, |C|).
2519  Upper = C->abs();
2520  Lower = (-Upper) + 1;
2521  }
2522  break;
2523 
2524  case Instruction::URem:
2525  if (match(BO.getOperand(1), m_APInt(C)))
2526  // 'urem x, C' produces [0, C).
2527  Upper = *C;
2528  break;
2529 
2530  default:
2531  break;
2532  }
2533 }
2534 
2536  Value *RHS) {
2537  const APInt *C;
2538  if (!match(RHS, m_APInt(C)))
2539  return nullptr;
2540 
2541  // Rule out tautological comparisons (eg., ult 0 or uge 0).
2543  if (RHS_CR.isEmptySet())
2544  return ConstantInt::getFalse(GetCompareTy(RHS));
2545  if (RHS_CR.isFullSet())
2546  return ConstantInt::getTrue(GetCompareTy(RHS));
2547 
2548  // Find the range of possible values for binary operators.
2549  unsigned Width = C->getBitWidth();
2550  APInt Lower = APInt(Width, 0);
2551  APInt Upper = APInt(Width, 0);
2552  if (auto *BO = dyn_cast<BinaryOperator>(LHS))
2553  setLimitsForBinOp(*BO, Lower, Upper);
2554 
2555  ConstantRange LHS_CR =
2556  Lower != Upper ? ConstantRange(Lower, Upper) : ConstantRange(Width, true);
2557 
2558  if (auto *I = dyn_cast<Instruction>(LHS))
2559  if (auto *Ranges = I->getMetadata(LLVMContext::MD_range))
2560  LHS_CR = LHS_CR.intersectWith(getConstantRangeFromMetadata(*Ranges));
2561 
2562  if (!LHS_CR.isFullSet()) {
2563  if (RHS_CR.contains(LHS_CR))
2564  return ConstantInt::getTrue(GetCompareTy(RHS));
2565  if (RHS_CR.inverse().contains(LHS_CR))
2566  return ConstantInt::getFalse(GetCompareTy(RHS));
2567  }
2568 
2569  return nullptr;
2570 }
2571 
2572 /// TODO: A large part of this logic is duplicated in InstCombine's
2573 /// foldICmpBinOp(). We should be able to share that and avoid the code
2574 /// duplication.
2576  Value *RHS, const SimplifyQuery &Q,
2577  unsigned MaxRecurse) {
2578  Type *ITy = GetCompareTy(LHS); // The return type.
2579 
2580  BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2581  BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2582  if (MaxRecurse && (LBO || RBO)) {
2583  // Analyze the case when either LHS or RHS is an add instruction.
2584  Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
2585  // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2586  bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2587  if (LBO && LBO->getOpcode() == Instruction::Add) {
2588  A = LBO->getOperand(0);
2589  B = LBO->getOperand(1);
2590  NoLHSWrapProblem =
2591  ICmpInst::isEquality(Pred) ||
2592  (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2593  (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2594  }
2595  if (RBO && RBO->getOpcode() == Instruction::Add) {
2596  C = RBO->getOperand(0);
2597  D = RBO->getOperand(1);
2598  NoRHSWrapProblem =
2599  ICmpInst::isEquality(Pred) ||
2600  (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2601  (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2602  }
2603 
2604  // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2605  if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2606  if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2607  Constant::getNullValue(RHS->getType()), Q,
2608  MaxRecurse - 1))
2609  return V;
2610 
2611  // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2612  if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2613  if (Value *V =
2615  C == LHS ? D : C, Q, MaxRecurse - 1))
2616  return V;
2617 
2618  // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2619  if (A && C && (A == C || A == D || B == C || B == D) && NoLHSWrapProblem &&
2620  NoRHSWrapProblem) {
2621  // Determine Y and Z in the form icmp (X+Y), (X+Z).
2622  Value *Y, *Z;
2623  if (A == C) {
2624  // C + B == C + D -> B == D
2625  Y = B;
2626  Z = D;
2627  } else if (A == D) {
2628  // D + B == C + D -> B == C
2629  Y = B;
2630  Z = C;
2631  } else if (B == C) {
2632  // A + C == C + D -> A == D
2633  Y = A;
2634  Z = D;
2635  } else {
2636  assert(B == D);
2637  // A + D == C + D -> A == C
2638  Y = A;
2639  Z = C;
2640  }
2641  if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse - 1))
2642  return V;
2643  }
2644  }
2645 
2646  {
2647  Value *Y = nullptr;
2648  // icmp pred (or X, Y), X
2649  if (LBO && match(LBO, m_c_Or(m_Value(Y), m_Specific(RHS)))) {
2650  if (Pred == ICmpInst::ICMP_ULT)
2651  return getFalse(ITy);
2652  if (Pred == ICmpInst::ICMP_UGE)
2653  return getTrue(ITy);
2654 
2655  if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SGE) {
2656  KnownBits RHSKnown = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2657  KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2658  if (RHSKnown.isNonNegative() && YKnown.isNegative())
2659  return Pred == ICmpInst::ICMP_SLT ? getTrue(ITy) : getFalse(ITy);
2660  if (RHSKnown.isNegative() || YKnown.isNonNegative())
2661  return Pred == ICmpInst::ICMP_SLT ? getFalse(ITy) : getTrue(ITy);
2662  }
2663  }
2664  // icmp pred X, (or X, Y)
2665  if (RBO && match(RBO, m_c_Or(m_Value(Y), m_Specific(LHS)))) {
2666  if (Pred == ICmpInst::ICMP_ULE)
2667  return getTrue(ITy);
2668  if (Pred == ICmpInst::ICMP_UGT)
2669  return getFalse(ITy);
2670 
2671  if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SLE) {
2672  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2673  KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2674  if (LHSKnown.isNonNegative() && YKnown.isNegative())
2675  return Pred == ICmpInst::ICMP_SGT ? getTrue(ITy) : getFalse(ITy);
2676  if (LHSKnown.isNegative() || YKnown.isNonNegative())
2677  return Pred == ICmpInst::ICMP_SGT ? getFalse(ITy) : getTrue(ITy);
2678  }
2679  }
2680  }
2681 
2682  // icmp pred (and X, Y), X
2683  if (LBO && match(LBO, m_c_And(m_Value(), m_Specific(RHS)))) {
2684  if (Pred == ICmpInst::ICMP_UGT)
2685  return getFalse(ITy);
2686  if (Pred == ICmpInst::ICMP_ULE)
2687  return getTrue(ITy);
2688  }
2689  // icmp pred X, (and X, Y)
2690  if (RBO && match(RBO, m_c_And(m_Value(), m_Specific(LHS)))) {
2691  if (Pred == ICmpInst::ICMP_UGE)
2692  return getTrue(ITy);
2693  if (Pred == ICmpInst::ICMP_ULT)
2694  return getFalse(ITy);
2695  }
2696 
2697  // 0 - (zext X) pred C
2698  if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
2699  if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
2700  if (RHSC->getValue().isStrictlyPositive()) {
2701  if (Pred == ICmpInst::ICMP_SLT)
2702  return ConstantInt::getTrue(RHSC->getContext());
2703  if (Pred == ICmpInst::ICMP_SGE)
2704  return ConstantInt::getFalse(RHSC->getContext());
2705  if (Pred == ICmpInst::ICMP_EQ)
2706  return ConstantInt::getFalse(RHSC->getContext());
2707  if (Pred == ICmpInst::ICMP_NE)
2708  return ConstantInt::getTrue(RHSC->getContext());
2709  }
2710  if (RHSC->getValue().isNonNegative()) {
2711  if (Pred == ICmpInst::ICMP_SLE)
2712  return ConstantInt::getTrue(RHSC->getContext());
2713  if (Pred == ICmpInst::ICMP_SGT)
2714  return ConstantInt::getFalse(RHSC->getContext());
2715  }
2716  }
2717  }
2718 
2719  // icmp pred (urem X, Y), Y
2720  if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2721  switch (Pred) {
2722  default:
2723  break;
2724  case ICmpInst::ICMP_SGT:
2725  case ICmpInst::ICMP_SGE: {
2726  KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2727  if (!Known.isNonNegative())
2728  break;
2730  }
2731  case ICmpInst::ICMP_EQ:
2732  case ICmpInst::ICMP_UGT:
2733  case ICmpInst::ICMP_UGE:
2734  return getFalse(ITy);
2735  case ICmpInst::ICMP_SLT:
2736  case ICmpInst::ICMP_SLE: {
2737  KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2738  if (!Known.isNonNegative())
2739  break;
2741  }
2742  case ICmpInst::ICMP_NE:
2743  case ICmpInst::ICMP_ULT:
2744  case ICmpInst::ICMP_ULE:
2745  return getTrue(ITy);
2746  }
2747  }
2748 
2749  // icmp pred X, (urem Y, X)
2750  if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2751  switch (Pred) {
2752  default:
2753  break;
2754  case ICmpInst::ICMP_SGT:
2755  case ICmpInst::ICMP_SGE: {
2756  KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2757  if (!Known.isNonNegative())
2758  break;
2760  }
2761  case ICmpInst::ICMP_NE:
2762  case ICmpInst::ICMP_UGT:
2763  case ICmpInst::ICMP_UGE:
2764  return getTrue(ITy);
2765  case ICmpInst::ICMP_SLT:
2766  case ICmpInst::ICMP_SLE: {
2767  KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2768  if (!Known.isNonNegative())
2769  break;
2771  }
2772  case ICmpInst::ICMP_EQ:
2773  case ICmpInst::ICMP_ULT:
2774  case ICmpInst::ICMP_ULE:
2775  return getFalse(ITy);
2776  }
2777  }
2778 
2779  // x >> y <=u x
2780  // x udiv y <=u x.
2781  if (LBO && (match(LBO, m_LShr(m_Specific(RHS), m_Value())) ||
2782  match(LBO, m_UDiv(m_Specific(RHS), m_Value())))) {
2783  // icmp pred (X op Y), X
2784  if (Pred == ICmpInst::ICMP_UGT)
2785  return getFalse(ITy);
2786  if (Pred == ICmpInst::ICMP_ULE)
2787  return getTrue(ITy);
2788  }
2789 
2790  // x >=u x >> y
2791  // x >=u x udiv y.
2792  if (RBO && (match(RBO, m_LShr(m_Specific(LHS), m_Value())) ||
2793  match(RBO, m_UDiv(m_Specific(LHS), m_Value())))) {
2794  // icmp pred X, (X op Y)
2795  if (Pred == ICmpInst::ICMP_ULT)
2796  return getFalse(ITy);
2797  if (Pred == ICmpInst::ICMP_UGE)
2798  return getTrue(ITy);
2799  }
2800 
2801  // handle:
2802  // CI2 << X == CI
2803  // CI2 << X != CI
2804  //
2805  // where CI2 is a power of 2 and CI isn't
2806  if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
2807  const APInt *CI2Val, *CIVal = &CI->getValue();
2808  if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
2809  CI2Val->isPowerOf2()) {
2810  if (!CIVal->isPowerOf2()) {
2811  // CI2 << X can equal zero in some circumstances,
2812  // this simplification is unsafe if CI is zero.
2813  //
2814  // We know it is safe if:
2815  // - The shift is nsw, we can't shift out the one bit.
2816  // - The shift is nuw, we can't shift out the one bit.
2817  // - CI2 is one
2818  // - CI isn't zero
2819  if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
2820  CI2Val->isOneValue() || !CI->isZero()) {
2821  if (Pred == ICmpInst::ICMP_EQ)
2822  return ConstantInt::getFalse(RHS->getContext());
2823  if (Pred == ICmpInst::ICMP_NE)
2824  return ConstantInt::getTrue(RHS->getContext());
2825  }
2826  }
2827  if (CIVal->isSignMask() && CI2Val->isOneValue()) {
2828  if (Pred == ICmpInst::ICMP_UGT)
2829  return ConstantInt::getFalse(RHS->getContext());
2830  if (Pred == ICmpInst::ICMP_ULE)
2831  return ConstantInt::getTrue(RHS->getContext());
2832  }
2833  }
2834  }
2835 
2836  if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2837  LBO->getOperand(1) == RBO->getOperand(1)) {
2838  switch (LBO->getOpcode()) {
2839  default:
2840  break;
2841  case Instruction::UDiv:
2842  case Instruction::LShr:
2843  if (ICmpInst::isSigned(Pred) || !LBO->isExact() || !RBO->isExact())
2844  break;
2845  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2846  RBO->getOperand(0), Q, MaxRecurse - 1))
2847  return V;
2848  break;
2849  case Instruction::SDiv:
2850  if (!ICmpInst::isEquality(Pred) || !LBO->isExact() || !RBO->isExact())
2851  break;
2852  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2853  RBO->getOperand(0), Q, MaxRecurse - 1))
2854  return V;
2855  break;
2856  case Instruction::AShr:
2857  if (!LBO->isExact() || !RBO->isExact())
2858  break;
2859  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2860  RBO->getOperand(0), Q, MaxRecurse - 1))
2861  return V;
2862  break;
2863  case Instruction::Shl: {
2864  bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2865  bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2866  if (!NUW && !NSW)
2867  break;
2868  if (!NSW && ICmpInst::isSigned(Pred))
2869  break;
2870  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2871  RBO->getOperand(0), Q, MaxRecurse - 1))
2872  return V;
2873  break;
2874  }
2875  }
2876  }
2877  return nullptr;
2878 }
2879 
2880 /// Simplify integer comparisons where at least one operand of the compare
2881 /// matches an integer min/max idiom.
2883  Value *RHS, const SimplifyQuery &Q,
2884  unsigned MaxRecurse) {
2885  Type *ITy = GetCompareTy(LHS); // The return type.
2886  Value *A, *B;
2888  CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2889 
2890  // Signed variants on "max(a,b)>=a -> true".
2891  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2892  if (A != RHS)
2893  std::swap(A, B); // smax(A, B) pred A.
2894  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2895  // We analyze this as smax(A, B) pred A.
2896  P = Pred;
2897  } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2898  (A == LHS || B == LHS)) {
2899  if (A != LHS)
2900  std::swap(A, B); // A pred smax(A, B).
2901  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2902  // We analyze this as smax(A, B) swapped-pred A.
2903  P = CmpInst::getSwappedPredicate(Pred);
2904  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2905  (A == RHS || B == RHS)) {
2906  if (A != RHS)
2907  std::swap(A, B); // smin(A, B) pred A.
2908  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2909  // We analyze this as smax(-A, -B) swapped-pred -A.
2910  // Note that we do not need to actually form -A or -B thanks to EqP.
2911  P = CmpInst::getSwappedPredicate(Pred);
2912  } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2913  (A == LHS || B == LHS)) {
2914  if (A != LHS)
2915  std::swap(A, B); // A pred smin(A, B).
2916  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2917  // We analyze this as smax(-A, -B) pred -A.
2918  // Note that we do not need to actually form -A or -B thanks to EqP.
2919  P = Pred;
2920  }
2921  if (P != CmpInst::BAD_ICMP_PREDICATE) {
2922  // Cases correspond to "max(A, B) p A".
2923  switch (P) {
2924  default:
2925  break;
2926  case CmpInst::ICMP_EQ:
2927  case CmpInst::ICMP_SLE:
2928  // Equivalent to "A EqP B". This may be the same as the condition tested
2929  // in the max/min; if so, we can just return that.
2930  if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2931  return V;
2932  if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2933  return V;
2934  // Otherwise, see if "A EqP B" simplifies.
2935  if (MaxRecurse)
2936  if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
2937  return V;
2938  break;
2939  case CmpInst::ICMP_NE:
2940  case CmpInst::ICMP_SGT: {
2942  // Equivalent to "A InvEqP B". This may be the same as the condition
2943  // tested in the max/min; if so, we can just return that.
2944  if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2945  return V;
2946  if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2947  return V;
2948  // Otherwise, see if "A InvEqP B" simplifies.
2949  if (MaxRecurse)
2950  if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
2951  return V;
2952  break;
2953  }
2954  case CmpInst::ICMP_SGE:
2955  // Always true.
2956  return getTrue(ITy);
2957  case CmpInst::ICMP_SLT:
2958  // Always false.
2959  return getFalse(ITy);
2960  }
2961  }
2962 
2963  // Unsigned variants on "max(a,b)>=a -> true".
2965  if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2966  if (A != RHS)
2967  std::swap(A, B); // umax(A, B) pred A.
2968  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2969  // We analyze this as umax(A, B) pred A.
2970  P = Pred;
2971  } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2972  (A == LHS || B == LHS)) {
2973  if (A != LHS)
2974  std::swap(A, B); // A pred umax(A, B).
2975  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2976  // We analyze this as umax(A, B) swapped-pred A.
2977  P = CmpInst::getSwappedPredicate(Pred);
2978  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2979  (A == RHS || B == RHS)) {
2980  if (A != RHS)
2981  std::swap(A, B); // umin(A, B) pred A.
2982  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2983  // We analyze this as umax(-A, -B) swapped-pred -A.
2984  // Note that we do not need to actually form -A or -B thanks to EqP.
2985  P = CmpInst::getSwappedPredicate(Pred);
2986  } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2987  (A == LHS || B == LHS)) {
2988  if (A != LHS)
2989  std::swap(A, B); // A pred umin(A, B).
2990  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2991  // We analyze this as umax(-A, -B) pred -A.
2992  // Note that we do not need to actually form -A or -B thanks to EqP.
2993  P = Pred;
2994  }
2995  if (P != CmpInst::BAD_ICMP_PREDICATE) {
2996  // Cases correspond to "max(A, B) p A".
2997  switch (P) {
2998  default:
2999  break;
3000  case CmpInst::ICMP_EQ:
3001  case CmpInst::ICMP_ULE:
3002  // Equivalent to "A EqP B". This may be the same as the condition tested
3003  // in the max/min; if so, we can just return that.
3004  if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
3005  return V;
3006  if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
3007  return V;
3008  // Otherwise, see if "A EqP B" simplifies.
3009  if (MaxRecurse)
3010  if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
3011  return V;
3012  break;
3013  case CmpInst::ICMP_NE:
3014  case CmpInst::ICMP_UGT: {
3016  // Equivalent to "A InvEqP B". This may be the same as the condition
3017  // tested in the max/min; if so, we can just return that.
3018  if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
3019  return V;
3020  if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
3021  return V;
3022  // Otherwise, see if "A InvEqP B" simplifies.
3023  if (MaxRecurse)
3024  if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
3025  return V;
3026  break;
3027  }
3028  case CmpInst::ICMP_UGE:
3029  // Always true.
3030  return getTrue(ITy);
3031  case CmpInst::ICMP_ULT:
3032  // Always false.
3033  return getFalse(ITy);
3034  }
3035  }
3036 
3037  // Variants on "max(x,y) >= min(x,z)".
3038  Value *C, *D;
3039  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
3040  match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
3041  (A == C || A == D || B == C || B == D)) {
3042  // max(x, ?) pred min(x, ?).
3043  if (Pred == CmpInst::ICMP_SGE)
3044  // Always true.
3045  return getTrue(ITy);
3046  if (Pred == CmpInst::ICMP_SLT)
3047  // Always false.
3048  return getFalse(ITy);
3049  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
3050  match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
3051  (A == C || A == D || B == C || B == D)) {
3052  // min(x, ?) pred max(x, ?).
3053  if (Pred == CmpInst::ICMP_SLE)
3054  // Always true.
3055  return getTrue(ITy);
3056  if (Pred == CmpInst::ICMP_SGT)
3057  // Always false.
3058  return getFalse(ITy);
3059  } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
3060  match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
3061  (A == C || A == D || B == C || B == D)) {
3062  // max(x, ?) pred min(x, ?).
3063  if (Pred == CmpInst::ICMP_UGE)
3064  // Always true.
3065  return getTrue(ITy);
3066  if (Pred == CmpInst::ICMP_ULT)
3067  // Always false.
3068  return getFalse(ITy);
3069  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
3070  match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
3071  (A == C || A == D || B == C || B == D)) {
3072  // min(x, ?) pred max(x, ?).
3073  if (Pred == CmpInst::ICMP_ULE)
3074  // Always true.
3075  return getTrue(ITy);
3076  if (Pred == CmpInst::ICMP_UGT)
3077  // Always false.
3078  return getFalse(ITy);
3079  }
3080 
3081  return nullptr;
3082 }
3083 
3084 /// Given operands for an ICmpInst, see if we can fold the result.
3085 /// If not, this returns null.
3086 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3087  const SimplifyQuery &Q, unsigned MaxRecurse) {
3088  CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3089  assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
3090 
3091  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3092  if (Constant *CRHS = dyn_cast<Constant>(RHS))
3093  return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3094 
3095  // If we have a constant, make sure it is on the RHS.
3096  std::swap(LHS, RHS);
3097  Pred = CmpInst::getSwappedPredicate(Pred);
3098  }
3099 
3100  Type *ITy = GetCompareTy(LHS); // The return type.
3101 
3102  // icmp X, X -> true/false
3103  // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
3104  // because X could be 0.
3105  if (LHS == RHS || isa<UndefValue>(RHS))
3106  return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
3107 
3108  if (Value *V = simplifyICmpOfBools(Pred, LHS, RHS, Q))
3109  return V;
3110 
3111  if (Value *V = simplifyICmpWithZero(Pred, LHS, RHS, Q))
3112  return V;
3113 
3114  if (Value *V = simplifyICmpWithConstant(Pred, LHS, RHS))
3115  return V;
3116 
3117  // If both operands have range metadata, use the metadata
3118  // to simplify the comparison.
3119  if (isa<Instruction>(RHS) && isa<Instruction>(LHS)) {
3120  auto RHS_Instr = cast<Instruction>(RHS);
3121  auto LHS_Instr = cast<Instruction>(LHS);
3122 
3123  if (RHS_Instr->getMetadata(LLVMContext::MD_range) &&
3124  LHS_Instr->getMetadata(LLVMContext::MD_range)) {
3125  auto RHS_CR = getConstantRangeFromMetadata(
3126  *RHS_Instr->getMetadata(LLVMContext::MD_range));
3127  auto LHS_CR = getConstantRangeFromMetadata(
3128  *LHS_Instr->getMetadata(LLVMContext::MD_range));
3129 
3130  auto Satisfied_CR = ConstantRange::makeSatisfyingICmpRegion(Pred, RHS_CR);
3131  if (Satisfied_CR.contains(LHS_CR))
3132  return ConstantInt::getTrue(RHS->getContext());
3133 
3134  auto InversedSatisfied_CR = ConstantRange::makeSatisfyingICmpRegion(
3135  CmpInst::getInversePredicate(Pred), RHS_CR);
3136  if (InversedSatisfied_CR.contains(LHS_CR))
3137  return ConstantInt::getFalse(RHS->getContext());
3138  }
3139  }
3140 
3141  // Compare of cast, for example (zext X) != 0 -> X != 0
3142  if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
3143  Instruction *LI = cast<CastInst>(LHS);
3144  Value *SrcOp = LI->getOperand(0);
3145  Type *SrcTy = SrcOp->getType();
3146  Type *DstTy = LI->getType();
3147 
3148  // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
3149  // if the integer type is the same size as the pointer type.
3150  if (MaxRecurse && isa<PtrToIntInst>(LI) &&
3151  Q.DL.getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
3152  if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
3153  // Transfer the cast to the constant.
3154  if (Value *V = SimplifyICmpInst(Pred, SrcOp,
3155  ConstantExpr::getIntToPtr(RHSC, SrcTy),
3156  Q, MaxRecurse-1))
3157  return V;
3158  } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
3159  if (RI->getOperand(0)->getType() == SrcTy)
3160  // Compare without the cast.
3161  if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
3162  Q, MaxRecurse-1))
3163  return V;
3164  }
3165  }
3166 
3167  if (isa<ZExtInst>(LHS)) {
3168  // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
3169  // same type.
3170  if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
3171  if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3172  // Compare X and Y. Note that signed predicates become unsigned.
3174  SrcOp, RI->getOperand(0), Q,
3175  MaxRecurse-1))
3176  return V;
3177  }
3178  // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
3179  // too. If not, then try to deduce the result of the comparison.
3180  else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3181  // Compute the constant that would happen if we truncated to SrcTy then
3182  // reextended to DstTy.
3183  Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3184  Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
3185 
3186  // If the re-extended constant didn't change then this is effectively
3187  // also a case of comparing two zero-extended values.
3188  if (RExt == CI && MaxRecurse)
3190  SrcOp, Trunc, Q, MaxRecurse-1))
3191  return V;
3192 
3193  // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
3194  // there. Use this to work out the result of the comparison.
3195  if (RExt != CI) {
3196  switch (Pred) {
3197  default: llvm_unreachable("Unknown ICmp predicate!");
3198  // LHS <u RHS.
3199  case ICmpInst::ICMP_EQ:
3200  case ICmpInst::ICMP_UGT:
3201  case ICmpInst::ICMP_UGE:
3202  return ConstantInt::getFalse(CI->getContext());
3203 
3204  case ICmpInst::ICMP_NE:
3205  case ICmpInst::ICMP_ULT:
3206  case ICmpInst::ICMP_ULE:
3207  return ConstantInt::getTrue(CI->getContext());
3208 
3209  // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
3210  // is non-negative then LHS <s RHS.
3211  case ICmpInst::ICMP_SGT:
3212  case ICmpInst::ICMP_SGE:
3213  return CI->getValue().isNegative() ?
3214  ConstantInt::getTrue(CI->getContext()) :
3215  ConstantInt::getFalse(CI->getContext());
3216 
3217  case ICmpInst::ICMP_SLT:
3218  case ICmpInst::ICMP_SLE:
3219  return CI->getValue().isNegative() ?
3220  ConstantInt::getFalse(CI->getContext()) :
3221  ConstantInt::getTrue(CI->getContext());
3222  }
3223  }
3224  }
3225  }
3226 
3227  if (isa<SExtInst>(LHS)) {
3228  // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
3229  // same type.
3230  if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
3231  if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3232  // Compare X and Y. Note that the predicate does not change.
3233  if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
3234  Q, MaxRecurse-1))
3235  return V;
3236  }
3237  // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
3238  // too. If not, then try to deduce the result of the comparison.
3239  else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3240  // Compute the constant that would happen if we truncated to SrcTy then
3241  // reextended to DstTy.
3242  Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3243  Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
3244 
3245  // If the re-extended constant didn't change then this is effectively
3246  // also a case of comparing two sign-extended values.
3247  if (RExt == CI && MaxRecurse)
3248  if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
3249  return V;
3250 
3251  // Otherwise the upper bits of LHS are all equal, while RHS has varying
3252  // bits there. Use this to work out the result of the comparison.
3253  if (RExt != CI) {
3254  switch (Pred) {
3255  default: llvm_unreachable("Unknown ICmp predicate!");
3256  case ICmpInst::ICMP_EQ:
3257  return ConstantInt::getFalse(CI->getContext());
3258  case ICmpInst::ICMP_NE:
3259  return ConstantInt::getTrue(CI->getContext());
3260 
3261  // If RHS is non-negative then LHS <s RHS. If RHS is negative then
3262  // LHS >s RHS.
3263  case ICmpInst::ICMP_SGT:
3264  case ICmpInst::ICMP_SGE:
3265  return CI->getValue().isNegative() ?
3266  ConstantInt::getTrue(CI->getContext()) :
3267  ConstantInt::getFalse(CI->getContext());
3268  case ICmpInst::ICMP_SLT:
3269  case ICmpInst::ICMP_SLE:
3270  return CI->getValue().isNegative() ?
3271  ConstantInt::getFalse(CI->getContext()) :
3272  ConstantInt::getTrue(CI->getContext());
3273 
3274  // If LHS is non-negative then LHS <u RHS. If LHS is negative then
3275  // LHS >u RHS.
3276  case ICmpInst::ICMP_UGT:
3277  case ICmpInst::ICMP_UGE:
3278  // Comparison is true iff the LHS <s 0.
3279  if (MaxRecurse)
3280  if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
3281  Constant::getNullValue(SrcTy),
3282  Q, MaxRecurse-1))
3283  return V;
3284  break;
3285  case ICmpInst::ICMP_ULT:
3286  case ICmpInst::ICMP_ULE:
3287  // Comparison is true iff the LHS >=s 0.
3288  if (MaxRecurse)
3289  if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
3290  Constant::getNullValue(SrcTy),
3291  Q, MaxRecurse-1))
3292  return V;
3293  break;
3294  }
3295  }
3296  }
3297  }
3298  }
3299 
3300  // icmp eq|ne X, Y -> false|true if X != Y
3301  if (ICmpInst::isEquality(Pred) &&
3302  isKnownNonEqual(LHS, RHS, Q.DL, Q.AC, Q.CxtI, Q.DT)) {
3303  return Pred == ICmpInst::ICMP_NE ? getTrue(ITy) : getFalse(ITy);
3304  }
3305 
3306  if (Value *V = simplifyICmpWithBinOp(Pred, LHS, RHS, Q, MaxRecurse))
3307  return V;
3308 
3309  if (Value *V = simplifyICmpWithMinMax(Pred, LHS, RHS, Q, MaxRecurse))
3310  return V;
3311 
3312  // Simplify comparisons of related pointers using a powerful, recursive
3313  // GEP-walk when we have target data available..
3314  if (LHS->getType()->isPointerTy())
3315  if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.CxtI, LHS, RHS))
3316  return C;
3317  if (auto *CLHS = dyn_cast<PtrToIntOperator>(LHS))
3318  if (auto *CRHS = dyn_cast<PtrToIntOperator>(RHS))
3319  if (Q.DL.getTypeSizeInBits(CLHS->getPointerOperandType()) ==
3320  Q.DL.getTypeSizeInBits(CLHS->getType()) &&
3321  Q.DL.getTypeSizeInBits(CRHS->getPointerOperandType()) ==
3322  Q.DL.getTypeSizeInBits(CRHS->getType()))
3323  if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.CxtI,
3324  CLHS->getPointerOperand(),
3325  CRHS->getPointerOperand()))
3326  return C;
3327 
3328  if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
3329  if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
3330  if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
3331  GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
3332  (ICmpInst::isEquality(Pred) ||
3333  (GLHS->isInBounds() && GRHS->isInBounds() &&
3334  Pred == ICmpInst::getSignedPredicate(Pred)))) {
3335  // The bases are equal and the indices are constant. Build a constant
3336  // expression GEP with the same indices and a null base pointer to see
3337  // what constant folding can make out of it.
3338  Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
3339  SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
3341  GLHS->getSourceElementType(), Null, IndicesLHS);
3342 
3343  SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
3345  GLHS->getSourceElementType(), Null, IndicesRHS);
3346  return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
3347  }
3348  }
3349  }
3350 
3351  // If the comparison is with the result of a select instruction, check whether
3352  // comparing with either branch of the select always yields the same value.
3353  if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3354  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3355  return V;
3356 
3357  // If the comparison is with the result of a phi instruction, check whether
3358  // doing the compare with each incoming phi value yields a common result.
3359  if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3360  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3361  return V;
3362 
3363  return nullptr;
3364 }
3365 
3366 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3367  const SimplifyQuery &Q) {
3368  return ::SimplifyICmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
3369 }
3370 
3371 /// Given operands for an FCmpInst, see if we can fold the result.
3372 /// If not, this returns null.
3373 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3374  FastMathFlags FMF, const SimplifyQuery &Q,
3375  unsigned MaxRecurse) {
3376  CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3377  assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
3378 
3379  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3380  if (Constant *CRHS = dyn_cast<Constant>(RHS))
3381  return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3382 
3383  // If we have a constant, make sure it is on the RHS.
3384  std::swap(LHS, RHS);
3385  Pred = CmpInst::getSwappedPredicate(Pred);
3386  }
3387 
3388  // Fold trivial predicates.
3389  Type *RetTy = GetCompareTy(LHS);
3390  if (Pred == FCmpInst::FCMP_FALSE)
3391  return getFalse(RetTy);
3392  if (Pred == FCmpInst::FCMP_TRUE)
3393  return getTrue(RetTy);
3394 
3395  // UNO/ORD predicates can be trivially folded if NaNs are ignored.
3396  if (FMF.noNaNs()) {
3397  if (Pred == FCmpInst::FCMP_UNO)
3398  return getFalse(RetTy);
3399  if (Pred == FCmpInst::FCMP_ORD)
3400  return getTrue(RetTy);
3401  }
3402 
3403  // fcmp pred x, undef and fcmp pred undef, x
3404  // fold to true if unordered, false if ordered
3405  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS)) {
3406  // Choosing NaN for the undef will always make unordered comparison succeed
3407  // and ordered comparison fail.
3408  return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred));
3409  }
3410 
3411  // fcmp x,x -> true/false. Not all compares are foldable.
3412  if (LHS == RHS) {
3413  if (CmpInst::isTrueWhenEqual(Pred))
3414  return getTrue(RetTy);
3415  if (CmpInst::isFalseWhenEqual(Pred))
3416  return getFalse(RetTy);
3417  }
3418 
3419  // Handle fcmp with constant RHS
3420  const ConstantFP *CFP = nullptr;
3421  if (const auto *RHSC = dyn_cast<Constant>(RHS)) {
3422  if (RHS->getType()->isVectorTy())
3423  CFP = dyn_cast_or_null<ConstantFP>(RHSC->getSplatValue());
3424  else
3425  CFP = dyn_cast<ConstantFP>(RHSC);
3426  }
3427  if (CFP) {
3428  // If the constant is a nan, see if we can fold the comparison based on it.
3429  if (CFP->getValueAPF().isNaN()) {
3430  if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
3431  return getFalse(RetTy);
3432  assert(FCmpInst::isUnordered(Pred) &&
3433  "Comparison must be either ordered or unordered!");
3434  // True if unordered.
3435  return getTrue(RetTy);
3436  }
3437  // Check whether the constant is an infinity.
3438  if (CFP->getValueAPF().isInfinity()) {
3439  if (CFP->getValueAPF().isNegative()) {
3440  switch (Pred) {
3441  case FCmpInst::FCMP_OLT:
3442  // No value is ordered and less than negative infinity.
3443  return getFalse(RetTy);
3444  case FCmpInst::FCMP_UGE:
3445  // All values are unordered with or at least negative infinity.
3446  return getTrue(RetTy);
3447  default:
3448  break;
3449  }
3450  } else {
3451  switch (Pred) {
3452  case FCmpInst::FCMP_OGT:
3453  // No value is ordered and greater than infinity.
3454  return getFalse(RetTy);
3455  case FCmpInst::FCMP_ULE:
3456  // All values are unordered with and at most infinity.
3457  return getTrue(RetTy);
3458  default:
3459  break;
3460  }
3461  }
3462  }
3463  if (CFP->getValueAPF().isZero()) {
3464  switch (Pred) {
3465  case FCmpInst::FCMP_UGE:
3466  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3467  return getTrue(RetTy);
3468  break;
3469  case FCmpInst::FCMP_OLT:
3470  // X < 0
3471  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3472  return getFalse(RetTy);
3473  break;
3474  default:
3475  break;
3476  }
3477  }
3478  }
3479 
3480  // If the comparison is with the result of a select instruction, check whether
3481  // comparing with either branch of the select always yields the same value.
3482  if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3483  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3484  return V;
3485 
3486  // If the comparison is with the result of a phi instruction, check whether
3487  // doing the compare with each incoming phi value yields a common result.
3488  if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3489  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3490  return V;
3491 
3492  return nullptr;
3493 }
3494 
3495 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3496  FastMathFlags FMF, const SimplifyQuery &Q) {
3497  return ::SimplifyFCmpInst(Predicate, LHS, RHS, FMF, Q, RecursionLimit);
3498 }
3499 
3500 /// See if V simplifies when its operand Op is replaced with RepOp.
3501 static const Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
3502  const SimplifyQuery &Q,
3503  unsigned MaxRecurse) {
3504  // Trivial replacement.
3505  if (V == Op)
3506  return RepOp;
3507 
3508  // We cannot replace a constant, and shouldn't even try.
3509  if (isa<Constant>(Op))
3510  return nullptr;
3511 
3512  auto *I = dyn_cast<Instruction>(V);
3513  if (!I)
3514  return nullptr;
3515 
3516  // If this is a binary operator, try to simplify it with the replaced op.
3517  if (auto *B = dyn_cast<BinaryOperator>(I)) {
3518  // Consider:
3519  // %cmp = icmp eq i32 %x, 2147483647
3520  // %add = add nsw i32 %x, 1
3521  // %sel = select i1 %cmp, i32 -2147483648, i32 %add
3522  //
3523  // We can't replace %sel with %add unless we strip away the flags.
3524  if (isa<OverflowingBinaryOperator>(B))
3525  if (B->hasNoSignedWrap() || B->hasNoUnsignedWrap())
3526  return nullptr;
3527  if (isa<PossiblyExactOperator>(B))
3528  if (B->isExact())
3529  return nullptr;
3530 
3531  if (MaxRecurse) {
3532  if (B->getOperand(0) == Op)
3533  return SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), Q,
3534  MaxRecurse - 1);
3535  if (B->getOperand(1) == Op)
3536  return SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, Q,
3537  MaxRecurse - 1);
3538  }
3539  }
3540 
3541  // Same for CmpInsts.
3542  if (CmpInst *C = dyn_cast<CmpInst>(I)) {
3543  if (MaxRecurse) {
3544  if (C->getOperand(0) == Op)
3545  return SimplifyCmpInst(C->getPredicate(), RepOp, C->getOperand(1), Q,
3546  MaxRecurse - 1);
3547  if (C->getOperand(1) == Op)
3548  return SimplifyCmpInst(C->getPredicate(), C->getOperand(0), RepOp, Q,
3549  MaxRecurse - 1);
3550  }
3551  }
3552 
3553  // TODO: We could hand off more cases to instsimplify here.
3554 
3555  // If all operands are constant after substituting Op for RepOp then we can
3556  // constant fold the instruction.
3557  if (Constant *CRepOp = dyn_cast<Constant>(RepOp)) {
3558  // Build a list of all constant operands.
3559  SmallVector<Constant *, 8> ConstOps;
3560  for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
3561  if (I->getOperand(i) == Op)
3562  ConstOps.push_back(CRepOp);
3563  else if (Constant *COp = dyn_cast<Constant>(I->getOperand(i)))
3564  ConstOps.push_back(COp);
3565  else
3566  break;
3567  }
3568 
3569  // All operands were constants, fold it.
3570  if (ConstOps.size() == I->getNumOperands()) {
3571  if (CmpInst *C = dyn_cast<CmpInst>(I))
3572  return ConstantFoldCompareInstOperands(C->getPredicate(), ConstOps[0],
3573  ConstOps[1], Q.DL, Q.TLI);
3574 
3575  if (LoadInst *LI = dyn_cast<LoadInst>(I))
3576  if (!LI->isVolatile())
3577  return ConstantFoldLoadFromConstPtr(ConstOps[0], LI->getType(), Q.DL);
3578 
3579  return ConstantFoldInstOperands(I, ConstOps, Q.DL, Q.TLI);
3580  }
3581  }
3582 
3583  return nullptr;
3584 }
3585 
3586 /// Try to simplify a select instruction when its condition operand is an
3587 /// integer comparison where one operand of the compare is a constant.
3588 static Value *simplifySelectBitTest(Value *TrueVal, Value *FalseVal, Value *X,
3589  const APInt *Y, bool TrueWhenUnset) {
3590  const APInt *C;
3591 
3592  // (X & Y) == 0 ? X & ~Y : X --> X
3593  // (X & Y) != 0 ? X & ~Y : X --> X & ~Y
3594  if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) &&
3595  *Y == ~*C)
3596  return TrueWhenUnset ? FalseVal : TrueVal;
3597 
3598  // (X & Y) == 0 ? X : X & ~Y --> X & ~Y
3599  // (X & Y) != 0 ? X : X & ~Y --> X
3600  if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) &&
3601  *Y == ~*C)
3602  return TrueWhenUnset ? FalseVal : TrueVal;
3603 
3604  if (Y->isPowerOf2()) {
3605  // (X & Y) == 0 ? X | Y : X --> X | Y
3606  // (X & Y) != 0 ? X | Y : X --> X
3607  if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) &&
3608  *Y == *C)
3609  return TrueWhenUnset ? TrueVal : FalseVal;
3610 
3611  // (X & Y) == 0 ? X : X | Y --> X
3612  // (X & Y) != 0 ? X : X | Y --> X | Y
3613  if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) &&
3614  *Y == *C)
3615  return TrueWhenUnset ? TrueVal : FalseVal;
3616  }
3617 
3618  return nullptr;
3619 }
3620 
3621 /// An alternative way to test if a bit is set or not uses sgt/slt instead of
3622 /// eq/ne.
3623 static Value *simplifySelectWithFakeICmpEq(Value *CmpLHS, Value *TrueVal,
3624  Value *FalseVal,
3625  bool TrueWhenUnset) {
3626  unsigned BitWidth = TrueVal->getType()->getScalarSizeInBits();
3627  if (!BitWidth)
3628  return nullptr;
3629 
3630  APInt MinSignedValue;
3631  Value *X;
3632  if (match(CmpLHS, m_Trunc(m_Value(X))) && (X == TrueVal || X == FalseVal)) {
3633  // icmp slt (trunc X), 0 <--> icmp ne (and X, C), 0
3634  // icmp sgt (trunc X), -1 <--> icmp eq (and X, C), 0
3635  unsigned DestSize = CmpLHS->getType()->getScalarSizeInBits();
3636  MinSignedValue = APInt::getSignedMinValue(DestSize).zext(BitWidth);
3637  } else {
3638  // icmp slt X, 0 <--> icmp ne (and X, C), 0
3639  // icmp sgt X, -1 <--> icmp eq (and X, C), 0
3640  X = CmpLHS;
3641  MinSignedValue = APInt::getSignedMinValue(BitWidth);
3642  }
3643 
3644  if (Value *V = simplifySelectBitTest(TrueVal, FalseVal, X, &MinSignedValue,
3645  TrueWhenUnset))
3646  return V;
3647 
3648  return nullptr;
3649 }
3650 
3651 /// Try to simplify a select instruction when its condition operand is an
3652 /// integer comparison.
3653 static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
3654  Value *FalseVal, const SimplifyQuery &Q,
3655  unsigned MaxRecurse) {
3656  ICmpInst::Predicate Pred;
3657  Value *CmpLHS, *CmpRHS;
3658  if (!match(CondVal, m_ICmp(Pred, m_Value(CmpLHS), m_Value(CmpRHS))))
3659  return nullptr;
3660 
3661  // FIXME: This code is nearly duplicated in InstCombine. Using/refactoring
3662  // decomposeBitTestICmp() might help.
3663  if (ICmpInst::isEquality(Pred) && match(CmpRHS, m_Zero())) {
3664  Value *X;
3665  const APInt *Y;
3666  if (match(CmpLHS, m_And(m_Value(X), m_APInt(Y))))
3667  if (Value *V = simplifySelectBitTest(TrueVal, FalseVal, X, Y,
3668  Pred == ICmpInst::ICMP_EQ))
3669  return V;
3670  } else if (Pred == ICmpInst::ICMP_SLT && match(CmpRHS, m_Zero())) {
3671  // Comparing signed-less-than 0 checks if the sign bit is set.
3672  if (Value *V = simplifySelectWithFakeICmpEq(CmpLHS, TrueVal, FalseVal,
3673  false))
3674  return V;
3675  } else if (Pred == ICmpInst::ICMP_SGT && match(CmpRHS, m_AllOnes())) {
3676  // Comparing signed-greater-than -1 checks if the sign bit is not set.
3677  if (Value *V = simplifySelectWithFakeICmpEq(CmpLHS, TrueVal, FalseVal,
3678  true))
3679  return V;
3680  }
3681 
3682  if (CondVal->hasOneUse()) {
3683  const APInt *C;
3684  if (match(CmpRHS, m_APInt(C))) {
3685  // X < MIN ? T : F --> F
3686  if (Pred == ICmpInst::ICMP_SLT && C->isMinSignedValue())
3687  return FalseVal;
3688  // X < MIN ? T : F --> F
3689  if (Pred == ICmpInst::ICMP_ULT && C->isMinValue())
3690  return FalseVal;
3691  // X > MAX ? T : F --> F
3692  if (Pred == ICmpInst::ICMP_SGT && C->isMaxSignedValue())
3693  return FalseVal;
3694  // X > MAX ? T : F --> F
3695  if (Pred == ICmpInst::ICMP_UGT && C->isMaxValue())
3696  return FalseVal;
3697  }
3698  }
3699 
3700  // If we have an equality comparison, then we know the value in one of the
3701  // arms of the select. See if substituting this value into the arm and
3702  // simplifying the result yields the same value as the other arm.
3703  if (Pred == ICmpInst::ICMP_EQ) {
3704  if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3705  TrueVal ||
3706  SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3707  TrueVal)
3708  return FalseVal;
3709  if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3710  FalseVal ||
3711  SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3712  FalseVal)
3713  return FalseVal;
3714  } else if (Pred == ICmpInst::ICMP_NE) {
3715  if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3716  FalseVal ||
3717  SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3718  FalseVal)
3719  return TrueVal;
3720  if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3721  TrueVal ||
3722  SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3723  TrueVal)
3724  return TrueVal;
3725  }
3726 
3727  return nullptr;
3728 }
3729 
3730 /// Given operands for a SelectInst, see if we can fold the result.
3731 /// If not, this returns null.
3732 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
3733  Value *FalseVal, const SimplifyQuery &Q,
3734  unsigned MaxRecurse) {
3735  // select true, X, Y -> X
3736  // select false, X, Y -> Y
3737  if (Constant *CB = dyn_cast<Constant>(CondVal)) {
3738  if (CB->isAllOnesValue())
3739  return TrueVal;
3740  if (CB->isNullValue())
3741  return FalseVal;
3742  }
3743 
3744  // select C, X, X -> X
3745  if (TrueVal == FalseVal)
3746  return TrueVal;
3747 
3748  if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
3749  if (isa<Constant>(FalseVal))
3750  return FalseVal;
3751  return TrueVal;
3752  }
3753  if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
3754  return FalseVal;
3755  if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
3756  return TrueVal;
3757 
3758  if (Value *V =
3759  simplifySelectWithICmpCond(CondVal, TrueVal, FalseVal, Q, MaxRecurse))
3760  return V;
3761 
3762  return nullptr;
3763 }
3764 
3765 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3766  const SimplifyQuery &Q) {
3767  return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Q, RecursionLimit);
3768 }
3769 
3770 /// Given operands for an GetElementPtrInst, see if we can fold the result.
3771 /// If not, this returns null.
3773  const SimplifyQuery &Q, unsigned) {
3774  // The type of the GEP pointer operand.
3775  unsigned AS =
3776  cast<PointerType>(Ops[0]->getType()->getScalarType())->getAddressSpace();
3777 
3778  // getelementptr P -> P.
3779  if (Ops.size() == 1)
3780  return Ops[0];
3781 
3782  // Compute the (pointer) type returned by the GEP instruction.
3783  Type *LastType = GetElementPtrInst::getIndexedType(SrcTy, Ops.slice(1));
3784  Type *GEPTy = PointerType::get(LastType, AS);
3785  if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
3786  GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3787  else if (VectorType *VT = dyn_cast<VectorType>(Ops[1]->getType()))
3788  GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3789 
3790  if (isa<UndefValue>(Ops[0]))
3791  return UndefValue::get(GEPTy);
3792 
3793  if (Ops.size() == 2) {
3794  // getelementptr P, 0 -> P.
3795  if (match(Ops[1], m_Zero()))
3796  return Ops[0];
3797 
3798  Type *Ty = SrcTy;
3799  if (Ty->isSized()) {
3800  Value *P;
3801  uint64_t C;
3802  uint64_t TyAllocSize = Q.DL.getTypeAllocSize(Ty);
3803  // getelementptr P, N -> P if P points to a type of zero size.
3804  if (TyAllocSize == 0)
3805  return Ops[0];
3806 
3807  // The following transforms are only safe if the ptrtoint cast
3808  // doesn't truncate the pointers.
3809  if (Ops[1]->getType()->getScalarSizeInBits() ==
3810  Q.DL.getPointerSizeInBits(AS)) {
3811  auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
3812  if (match(P, m_Zero()))
3813  return Constant::getNullValue(GEPTy);
3814  Value *Temp;
3815  if (match(P, m_PtrToInt(m_Value(Temp))))
3816  if (Temp->getType() == GEPTy)
3817  return Temp;
3818  return nullptr;
3819  };
3820 
3821  // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
3822  if (TyAllocSize == 1 &&
3823  match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
3824  if (Value *R = PtrToIntOrZero(P))
3825  return R;
3826 
3827  // getelementptr V, (ashr (sub P, V), C) -> Q
3828  // if P points to a type of size 1 << C.
3829  if (match(Ops[1],
3830  m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3831  m_ConstantInt(C))) &&
3832  TyAllocSize == 1ULL << C)
3833  if (Value *R = PtrToIntOrZero(P))
3834  return R;
3835 
3836  // getelementptr V, (sdiv (sub P, V), C) -> Q
3837  // if P points to a type of size C.
3838  if (match(Ops[1],
3839  m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3840  m_SpecificInt(TyAllocSize))))
3841  if (Value *R = PtrToIntOrZero(P))
3842  return R;
3843  }
3844  }
3845  }
3846 
3847  if (Q.DL.getTypeAllocSize(LastType) == 1 &&
3848  all_of(Ops.slice(1).drop_back(1),
3849  [](Value *Idx) { return match(Idx, m_Zero()); })) {
3850  unsigned PtrWidth =
3851  Q.DL.getPointerSizeInBits(Ops[0]->getType()->getPointerAddressSpace());
3852  if (Q.DL.getTypeSizeInBits(Ops.back()->getType()) == PtrWidth) {
3853  APInt BasePtrOffset(PtrWidth, 0);
3854  Value *StrippedBasePtr =
3855  Ops[0]->stripAndAccumulateInBoundsConstantOffsets(Q.DL,
3856  BasePtrOffset);
3857 
3858  // gep (gep V, C), (sub 0, V) -> C
3859  if (match(Ops.back(),
3860  m_Sub(m_Zero(), m_PtrToInt(m_Specific(StrippedBasePtr))))) {
3861  auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset);
3862  return ConstantExpr::getIntToPtr(CI, GEPTy);
3863  }
3864  // gep (gep V, C), (xor V, -1) -> C-1
3865  if (match(Ops.back(),
3866  m_Xor(m_PtrToInt(m_Specific(StrippedBasePtr)), m_AllOnes()))) {
3867  auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset - 1);
3868  return ConstantExpr::getIntToPtr(CI, GEPTy);
3869  }
3870  }
3871  }
3872 
3873  // Check to see if this is constant foldable.
3874  if (!all_of(Ops, [](Value *V) { return isa<Constant>(V); }))
3875  return nullptr;
3876 
3877  auto *CE = ConstantExpr::getGetElementPtr(SrcTy, cast<Constant>(Ops[0]),
3878  Ops.slice(1));
3879  if (auto *CEFolded = ConstantFoldConstant(CE, Q.DL))
3880  return CEFolded;
3881  return CE;
3882 }
3883 
3885  const SimplifyQuery &Q) {
3886  return ::SimplifyGEPInst(SrcTy, Ops, Q, RecursionLimit);
3887 }
3888 
3889 /// Given operands for an InsertValueInst, see if we can fold the result.
3890 /// If not, this returns null.
3892  ArrayRef<unsigned> Idxs, const SimplifyQuery &Q,
3893  unsigned) {
3894  if (Constant *CAgg = dyn_cast<Constant>(Agg))
3895  if (Constant *CVal = dyn_cast<Constant>(Val))
3896  return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
3897 
3898  // insertvalue x, undef, n -> x
3899  if (match(Val, m_Undef()))
3900  return Agg;
3901 
3902  // insertvalue x, (extractvalue y, n), n
3903  if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
3904  if (EV->getAggregateOperand()->getType() == Agg->getType() &&
3905  EV->getIndices() == Idxs) {
3906  // insertvalue undef, (extractvalue y, n), n -> y
3907  if (match(Agg, m_Undef()))
3908  return EV->getAggregateOperand();
3909 
3910  // insertvalue y, (extractvalue y, n), n -> y
3911  if (Agg == EV->getAggregateOperand())
3912  return Agg;
3913  }
3914 
3915  return nullptr;
3916 }
3917 
3919  ArrayRef<unsigned> Idxs,
3920  const SimplifyQuery &Q) {
3922 }
3923 
3924 /// Given operands for an ExtractValueInst, see if we can fold the result.
3925 /// If not, this returns null.
3927  const SimplifyQuery &, unsigned) {
3928  if (auto *CAgg = dyn_cast<Constant>(Agg))
3929  return ConstantFoldExtractValueInstruction(CAgg, Idxs);
3930 
3931  // extractvalue x, (insertvalue y, elt, n), n -> elt
3932  unsigned NumIdxs = Idxs.size();
3933  for (auto *IVI = dyn_cast<InsertValueInst>(Agg); IVI != nullptr;
3934  IVI = dyn_cast<InsertValueInst>(IVI->getAggregateOperand())) {
3935  ArrayRef<unsigned> InsertValueIdxs = IVI->getIndices();
3936  unsigned NumInsertValueIdxs = InsertValueIdxs.size();
3937  unsigned NumCommonIdxs = std::min(NumInsertValueIdxs, NumIdxs);
3938  if (InsertValueIdxs.slice(0, NumCommonIdxs) ==
3939  Idxs.slice(0, NumCommonIdxs)) {
3940  if (NumIdxs == NumInsertValueIdxs)
3941  return IVI->getInsertedValueOperand();
3942  break;
3943  }
3944  }
3945 
3946  return nullptr;
3947 }
3948 
3950  const SimplifyQuery &Q) {
3952 }
3953 
3954 /// Given operands for an ExtractElementInst, see if we can fold the result.
3955 /// If not, this returns null.
3957  unsigned) {
3958  if (auto *CVec = dyn_cast<Constant>(Vec)) {
3959  if (auto *CIdx = dyn_cast<Constant>(Idx))
3960  return ConstantFoldExtractElementInstruction(CVec, CIdx);
3961 
3962  // The index is not relevant if our vector is a splat.
3963  if (auto *Splat = CVec->getSplatValue())
3964  return Splat;
3965 
3966  if (isa<UndefValue>(Vec))
3967  return UndefValue::get(Vec->getType()->getVectorElementType());
3968  }
3969 
3970  // If extracting a specified index from the vector, see if we can recursively
3971  // find a previously computed scalar that was inserted into the vector.
3972  if (auto *IdxC = dyn_cast<ConstantInt>(Idx))
3973  if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue()))
3974  return Elt;
3975 
3976  return nullptr;
3977 }
3978 
3980  const SimplifyQuery &Q) {
3982 }
3983 
3984 /// See if we can fold the given phi. If not, returns null.
3985 static Value *SimplifyPHINode(PHINode *PN, const SimplifyQuery &Q) {
3986  // If all of the PHI's incoming values are the same then replace the PHI node
3987  // with the common value.
3988  Value *CommonValue = nullptr;
3989  bool HasUndefInput = false;
3990  for (Value *Incoming : PN->incoming_values()) {
3991  // If the incoming value is the phi node itself, it can safely be skipped.
3992  if (Incoming == PN) continue;
3993  if (isa<UndefValue>(Incoming)) {
3994  // Remember that we saw an undef value, but otherwise ignore them.
3995  HasUndefInput = true;
3996  continue;
3997  }
3998  if (CommonValue && Incoming != CommonValue)
3999  return nullptr; // Not the same, bail out.
4000  CommonValue = Incoming;
4001  }
4002 
4003  // If CommonValue is null then all of the incoming values were either undef or
4004  // equal to the phi node itself.
4005  if (!CommonValue)
4006  return UndefValue::get(PN->getType());
4007 
4008  // If we have a PHI node like phi(X, undef, X), where X is defined by some
4009  // instruction, we cannot return X as the result of the PHI node unless it
4010  // dominates the PHI block.
4011  if (HasUndefInput)
4012  return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
4013 
4014  return CommonValue;
4015 }
4016 
4017 static Value *SimplifyCastInst(unsigned CastOpc, Value *Op,
4018  Type *Ty, const SimplifyQuery &Q, unsigned MaxRecurse) {
4019  if (auto *C = dyn_cast<Constant>(Op))
4020  return ConstantFoldCastOperand(CastOpc, C, Ty, Q.DL);
4021 
4022  if (auto *CI = dyn_cast<CastInst>(Op)) {
4023  auto *Src = CI->getOperand(0);
4024  Type *SrcTy = Src->getType();
4025  Type *MidTy = CI->getType();
4026  Type *DstTy = Ty;
4027  if (Src->getType() == Ty) {
4028  auto FirstOp = static_cast<Instruction::CastOps>(CI->getOpcode());
4029  auto SecondOp = static_cast<Instruction::CastOps>(CastOpc);
4030  Type *SrcIntPtrTy =
4031  SrcTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(SrcTy) : nullptr;
4032  Type *MidIntPtrTy =
4033  MidTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(MidTy) : nullptr;
4034  Type *DstIntPtrTy =
4035  DstTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(DstTy) : nullptr;
4036  if (CastInst::isEliminableCastPair(FirstOp, SecondOp, SrcTy, MidTy, DstTy,
4037  SrcIntPtrTy, MidIntPtrTy,
4038  DstIntPtrTy) == Instruction::BitCast)
4039  return Src;
4040  }
4041  }
4042 
4043  // bitcast x -> x
4044  if (CastOpc == Instruction::BitCast)
4045  if (Op->getType() == Ty)
4046  return Op;
4047 
4048  return nullptr;
4049 }
4050 
4051 Value *llvm::SimplifyCastInst(unsigned CastOpc, Value *Op, Type *Ty,
4052  const SimplifyQuery &Q) {
4053  return ::SimplifyCastInst(CastOpc, Op, Ty, Q, RecursionLimit);
4054 }
4055 
4056 /// For the given destination element of a shuffle, peek through shuffles to
4057 /// match a root vector source operand that contains that element in the same
4058 /// vector lane (ie, the same mask index), so we can eliminate the shuffle(s).
4059 static Value *foldIdentityShuffles(int DestElt, Value *Op0, Value *Op1,
4060  int MaskVal, Value *RootVec,
4061  unsigned MaxRecurse) {
4062  if (!MaxRecurse--)
4063  return nullptr;
4064 
4065  // Bail out if any mask value is undefined. That kind of shuffle may be
4066  // simplified further based on demanded bits or other folds.
4067  if (MaskVal == -1)
4068  return nullptr;
4069 
4070  // The mask value chooses which source operand we need to look at next.
4071  int InVecNumElts = Op0->getType()->getVectorNumElements();
4072  int RootElt = MaskVal;
4073  Value *SourceOp = Op0;
4074  if (MaskVal >= InVecNumElts) {
4075  RootElt = MaskVal - InVecNumElts;
4076  SourceOp = Op1;
4077  }
4078 
4079  // If the source operand is a shuffle itself, look through it to find the
4080  // matching root vector.
4081  if (auto *SourceShuf = dyn_cast<ShuffleVectorInst>(SourceOp)) {
4082  return foldIdentityShuffles(
4083  DestElt, SourceShuf->getOperand(0), SourceShuf->getOperand(1),
4084  SourceShuf->getMaskValue(RootElt), RootVec, MaxRecurse);
4085  }
4086 
4087  // TODO: Look through bitcasts? What if the bitcast changes the vector element
4088  // size?
4089 
4090  // The source operand is not a shuffle. Initialize the root vector value for
4091  // this shuffle if that has not been done yet.
4092  if (!RootVec)
4093  RootVec = SourceOp;
4094 
4095  // Give up as soon as a source operand does not match the existing root value.
4096  if (RootVec != SourceOp)
4097  return nullptr;
4098 
4099  // The element must be coming from the same lane in the source vector
4100  // (although it may have crossed lanes in intermediate shuffles).
4101  if (RootElt != DestElt)
4102  return nullptr;
4103 
4104  return RootVec;
4105 }
4106 
4108  Type *RetTy, const SimplifyQuery &Q,
4109  unsigned MaxRecurse) {
4110  if (isa<UndefValue>(Mask))
4111  return UndefValue::get(RetTy);
4112 
4113  Type *InVecTy = Op0->getType();
4114  unsigned MaskNumElts = Mask->getType()->getVectorNumElements();
4115  unsigned InVecNumElts = InVecTy->getVectorNumElements();
4116 
4117  SmallVector<int, 32> Indices;
4118  ShuffleVectorInst::getShuffleMask(Mask, Indices);
4119  assert(MaskNumElts == Indices.size() &&
4120  "Size of Indices not same as number of mask elements?");
4121 
4122  // Canonicalization: If mask does not select elements from an input vector,
4123  // replace that input vector with undef.
4124  bool MaskSelects0 = false, MaskSelects1 = false;
4125  for (unsigned i = 0; i != MaskNumElts; ++i) {
4126  if (Indices[i] == -1)
4127  continue;
4128  if ((unsigned)Indices[i] < InVecNumElts)
4129  MaskSelects0 = true;
4130  else
4131  MaskSelects1 = true;
4132  }
4133  if (!MaskSelects0)
4134  Op0 = UndefValue::get(InVecTy);
4135  if (!MaskSelects1)
4136  Op1 = UndefValue::get(InVecTy);
4137 
4138  auto *Op0Const = dyn_cast<Constant>(Op0);
4139  auto *Op1Const = dyn_cast<Constant>(Op1);
4140 
4141  // If all operands are constant, constant fold the shuffle.
4142  if (Op0Const && Op1Const)
4143  return ConstantFoldShuffleVectorInstruction(Op0Const, Op1Const, Mask);
4144 
4145  // Canonicalization: if only one input vector is constant, it shall be the
4146  // second one.
4147  if (Op0Const && !Op1Const) {
4148  std::swap(Op0, Op1);
4149  ShuffleVectorInst::commuteShuffleMask(Indices, InVecNumElts);
4150  }
4151 
4152  // A shuffle of a splat is always the splat itself. Legal if the shuffle's
4153  // value type is same as the input vectors' type.
4154  if (auto *OpShuf = dyn_cast<ShuffleVectorInst>(Op0))
4155  if (isa<UndefValue>(Op1) && RetTy == InVecTy &&
4156  OpShuf->getMask()->getSplatValue())
4157  return Op0;
4158 
4159  // Don't fold a shuffle with undef mask elements. This may get folded in a
4160  // better way using demanded bits or other analysis.
4161  // TODO: Should we allow this?
4162  if (find(Indices, -1) != Indices.end())
4163  return nullptr;
4164 
4165  // Check if every element of this shuffle can be mapped back to the
4166  // corresponding element of a single root vector. If so, we don't need this
4167  // shuffle. This handles simple identity shuffles as well as chains of
4168  // shuffles that may widen/narrow and/or move elements across lanes and back.
4169  Value *RootVec = nullptr;
4170  for (unsigned i = 0; i != MaskNumElts; ++i) {
4171  // Note that recursion is limited for each vector element, so if any element
4172  // exceeds the limit, this will fail to simplify.
4173  RootVec =
4174  foldIdentityShuffles(i, Op0, Op1, Indices[i], RootVec, MaxRecurse);
4175 
4176  // We can't replace a widening/narrowing shuffle with one of its operands.
4177  if (!RootVec || RootVec->getType() != RetTy)
4178  return nullptr;
4179  }
4180  return RootVec;
4181 }
4182 
4183 /// Given operands for a ShuffleVectorInst, fold the result or return null.
4185  Type *RetTy, const SimplifyQuery &Q) {
4186  return ::SimplifyShuffleVectorInst(Op0, Op1, Mask, RetTy, Q, RecursionLimit);
4187 }
4188 
4189 //=== Helper functions for higher up the class hierarchy.
4190 
4191 /// Given operands for a BinaryOperator, see if we can fold the result.
4192 /// If not, this returns null.
4193 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4194  const SimplifyQuery &Q, unsigned MaxRecurse) {
4195  switch (Opcode) {
4196  case Instruction::Add:
4197  return SimplifyAddInst(LHS, RHS, false, false, Q, MaxRecurse);
4198  case Instruction::FAdd:
4199  return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4200  case Instruction::Sub:
4201  return SimplifySubInst(LHS, RHS, false, false, Q, MaxRecurse);
4202  case Instruction::FSub:
4203  return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4204  case Instruction::Mul:
4205  return SimplifyMulInst(LHS, RHS, Q, MaxRecurse);
4206  case Instruction::FMul:
4207  return SimplifyFMulInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4208  case Instruction::SDiv:
4209  return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
4210  case Instruction::UDiv:
4211  return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
4212  case Instruction::FDiv:
4213  return SimplifyFDivInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4214  case Instruction::SRem:
4215  return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
4216  case Instruction::URem:
4217  return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
4218  case Instruction::FRem:
4219  return SimplifyFRemInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4220  case Instruction::Shl:
4221  return SimplifyShlInst(LHS, RHS, false, false, Q, MaxRecurse);
4222  case Instruction::LShr:
4223  return SimplifyLShrInst(LHS, RHS, false, Q, MaxRecurse);
4224  case Instruction::AShr:
4225  return SimplifyAShrInst(LHS, RHS, false, Q, MaxRecurse);
4226  case Instruction::And:
4227  return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
4228  case Instruction::Or:
4229  return SimplifyOrInst(LHS, RHS, Q, MaxRecurse);
4230  case Instruction::Xor:
4231  return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
4232  default:
4233  llvm_unreachable("Unexpected opcode");
4234  }
4235 }
4236 
4237 /// Given operands for a BinaryOperator, see if we can fold the result.
4238 /// If not, this returns null.
4239 /// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the
4240 /// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp.
4241 static Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4242  const FastMathFlags &FMF, const SimplifyQuery &Q,
4243  unsigned MaxRecurse) {
4244  switch (Opcode) {
4245  case Instruction::FAdd:
4246  return SimplifyFAddInst(LHS, RHS, FMF, Q, MaxRecurse);
4247  case Instruction::FSub:
4248  return SimplifyFSubInst(LHS, RHS, FMF, Q, MaxRecurse);
4249  case Instruction::FMul:
4250  return SimplifyFMulInst(LHS, RHS, FMF, Q, MaxRecurse);
4251  case Instruction::FDiv:
4252  return SimplifyFDivInst(LHS, RHS, FMF, Q, MaxRecurse);
4253  default:
4254  return SimplifyBinOp(Opcode, LHS, RHS, Q, MaxRecurse);
4255  }
4256 }
4257 
4258 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4259  const SimplifyQuery &Q) {
4260  return ::SimplifyBinOp(Opcode, LHS, RHS, Q, RecursionLimit);
4261 }
4262 
4263 Value *llvm::SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4264  FastMathFlags FMF, const SimplifyQuery &Q) {
4265  return ::SimplifyFPBinOp(Opcode, LHS, RHS, FMF, Q, RecursionLimit);
4266 }
4267 
4268 /// Given operands for a CmpInst, see if we can fold the result.
4269 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
4270  const SimplifyQuery &Q, unsigned MaxRecurse) {
4272  return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
4273  return SimplifyFCmpInst(Predicate, LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4274 }
4275 
4276 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
4277  const SimplifyQuery &Q) {
4278  return ::SimplifyCmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
4279 }
4280 
4282  switch (ID) {
4283  default: return false;
4284 
4285  // Unary idempotent: f(f(x)) = f(x)
4286  case Intrinsic::fabs:
4287  case Intrinsic::floor:
4288  case Intrinsic::ceil:
4289  case Intrinsic::trunc:
4290  case Intrinsic::rint:
4291  case Intrinsic::nearbyint:
4292  case Intrinsic::round:
4293  return true;
4294  }
4295 }
4296 
4298  const DataLayout &DL) {
4299  GlobalValue *PtrSym;
4300  APInt PtrOffset;
4301  if (!IsConstantOffsetFromGlobal(Ptr, PtrSym, PtrOffset, DL))
4302  return nullptr;
4303 
4304  Type *Int8PtrTy = Type::getInt8PtrTy(Ptr->getContext());
4306  Type *Int32PtrTy = Int32Ty->getPointerTo();
4307  Type *Int64Ty = Type::getInt64Ty(Ptr->getContext());
4308 
4309  auto *OffsetConstInt = dyn_cast<ConstantInt>(Offset);
4310  if (!OffsetConstInt || OffsetConstInt->getType()->getBitWidth() > 64)
4311  return nullptr;
4312 
4313  uint64_t OffsetInt = OffsetConstInt->getSExtValue();
4314  if (OffsetInt % 4 != 0)
4315  return nullptr;
4316 
4318  Int32Ty, ConstantExpr::getBitCast(Ptr, Int32PtrTy),
4319  ConstantInt::get(Int64Ty, OffsetInt / 4));
4320  Constant *Loaded = ConstantFoldLoadFromConstPtr(C, Int32Ty, DL);
4321  if (!Loaded)
4322  return nullptr;
4323 
4324  auto *LoadedCE = dyn_cast<ConstantExpr>(Loaded);
4325  if (!LoadedCE)
4326  return nullptr;
4327 
4328  if (LoadedCE->getOpcode() == Instruction::Trunc) {
4329  LoadedCE = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4330  if (!LoadedCE)
4331  return nullptr;
4332  }
4333 
4334  if (LoadedCE->getOpcode() != Instruction::Sub)
4335  return nullptr;
4336 
4337  auto *LoadedLHS = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4338  if (!LoadedLHS || LoadedLHS->getOpcode() != Instruction::PtrToInt)
4339  return nullptr;
4340  auto *LoadedLHSPtr = LoadedLHS->getOperand(0);
4341 
4342  Constant *LoadedRHS = LoadedCE->getOperand(1);
4343  GlobalValue *LoadedRHSSym;
4344  APInt LoadedRHSOffset;
4345  if (!IsConstantOffsetFromGlobal(LoadedRHS, LoadedRHSSym, LoadedRHSOffset,
4346  DL) ||
4347  PtrSym != LoadedRHSSym || PtrOffset != LoadedRHSOffset)
4348  return nullptr;
4349 
4350  return ConstantExpr::getBitCast(LoadedLHSPtr, Int8PtrTy);
4351 }
4352 
4354  auto *ConstMask = dyn_cast<Constant>(Mask);
4355  if (!ConstMask)
4356  return false;
4357  if (ConstMask->isNullValue() || isa<UndefValue>(ConstMask))
4358  return true;
4359  for (unsigned I = 0, E = ConstMask->getType()->getVectorNumElements(); I != E;
4360  ++I) {
4361  if (auto *MaskElt = ConstMask->getAggregateElement(I))
4362  if (MaskElt->isNullValue() || isa<UndefValue>(MaskElt))
4363  continue;
4364  return false;
4365  }
4366  return true;
4367 }
4368 
4369 template <typename IterTy>
4370 static Value *SimplifyIntrinsic(Function *F, IterTy ArgBegin, IterTy ArgEnd,
4371  const SimplifyQuery &Q, unsigned MaxRecurse) {
4372  Intrinsic::ID IID = F->getIntrinsicID();
4373  unsigned NumOperands = std::distance(ArgBegin, ArgEnd);
4374 
4375  // Unary Ops
4376  if (NumOperands == 1) {
4377  // Perform idempotent optimizations
4378  if (IsIdempotent(IID)) {
4379  if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin)) {
4380  if (II->getIntrinsicID() == IID)
4381  return II;
4382  }
4383  }
4384 
4385  switch (IID) {
4386  case Intrinsic::fabs: {
4387  if (SignBitMustBeZero(*ArgBegin, Q.TLI))
4388  return *ArgBegin;
4389  return nullptr;
4390  }
4391  default:
4392  return nullptr;
4393  }
4394  }
4395 
4396  // Binary Ops
4397  if (NumOperands == 2) {
4398  Value *LHS = *ArgBegin;
4399  Value *RHS = *(ArgBegin + 1);
4400  Type *ReturnType = F->getReturnType();
4401 
4402  switch (IID) {
4403  case Intrinsic::usub_with_overflow:
4404  case Intrinsic::ssub_with_overflow: {
4405  // X - X -> { 0, false }
4406  if (LHS == RHS)
4407  return Constant::getNullValue(ReturnType);
4408 
4409  // X - undef -> undef
4410  // undef - X -> undef
4411  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
4412  return UndefValue::get(ReturnType);
4413 
4414  return nullptr;
4415  }
4416  case Intrinsic::uadd_with_overflow:
4417  case Intrinsic::sadd_with_overflow: {
4418  // X + undef -> undef
4419  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
4420  return UndefValue::get(ReturnType);
4421 
4422  return nullptr;
4423  }
4424  case Intrinsic::umul_with_overflow:
4425  case Intrinsic::smul_with_overflow: {
4426  // 0 * X -> { 0, false }
4427  // X * 0 -> { 0, false }
4428  if (match(LHS, m_Zero()) || match(RHS, m_Zero()))
4429  return Constant::getNullValue(ReturnType);
4430 
4431  // undef * X -> { 0, false }
4432  // X * undef -> { 0, false }
4433  if (match(LHS, m_Undef()) || match(RHS, m_Undef()))
4434  return Constant::getNullValue(ReturnType);
4435 
4436  return nullptr;
4437  }
4438  case Intrinsic::load_relative: {
4439  Constant *C0 = dyn_cast<Constant>(LHS);
4440  Constant *C1 = dyn_cast<Constant>(RHS);
4441  if (C0 && C1)
4442  return SimplifyRelativeLoad(C0, C1, Q.DL);
4443  return nullptr;
4444  }
4445  default:
4446  return nullptr;
4447  }
4448  }
4449 
4450  // Simplify calls to llvm.masked.load.*
4451  switch (IID) {
4452  case Intrinsic::masked_load: {
4453  Value *MaskArg = ArgBegin[2];
4454  Value *PassthruArg = ArgBegin[3];
4455  // If the mask is all zeros or undef, the "passthru" argument is the result.
4456  if (maskIsAllZeroOrUndef(MaskArg))
4457  return PassthruArg;
4458  return nullptr;
4459  }
4460  default:
4461  return nullptr;
4462  }
4463 }
4464 
4465 template <typename IterTy>
4466 static Value *SimplifyCall(ImmutableCallSite CS, Value *V, IterTy ArgBegin,
4467  IterTy ArgEnd, const SimplifyQuery &Q,
4468  unsigned MaxRecurse) {
4469  Type *Ty = V->getType();
4470  if (PointerType *PTy = dyn_cast<PointerType>(Ty))
4471  Ty = PTy->getElementType();
4472  FunctionType *FTy = cast<FunctionType>(Ty);
4473 
4474  // call undef -> undef
4475  // call null -> undef
4476  if (isa<UndefValue>(V) || isa<ConstantPointerNull>(V))
4477  return UndefValue::get(FTy->getReturnType());
4478 
4479  Function *F = dyn_cast<Function>(V);
4480  if (!F)
4481  return nullptr;
4482 
4483  if (F->isIntrinsic())
4484  if (Value *Ret = SimplifyIntrinsic(F, ArgBegin, ArgEnd, Q, MaxRecurse))
4485  return Ret;
4486 
4487  if (!canConstantFoldCallTo(CS, F))
4488  return nullptr;
4489 
4490  SmallVector<Constant *, 4> ConstantArgs;
4491  ConstantArgs.reserve(ArgEnd - ArgBegin);
4492  for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
4493  Constant *C = dyn_cast<Constant>(*I);
4494  if (!C)
4495  return nullptr;
4496  ConstantArgs.push_back(C);
4497  }
4498 
4499  return ConstantFoldCall(CS, F, ConstantArgs, Q.TLI);
4500 }
4501 
4503  User::op_iterator ArgBegin, User::op_iterator ArgEnd,
4504  const SimplifyQuery &Q) {
4505  return ::SimplifyCall(CS, V, ArgBegin, ArgEnd, Q, RecursionLimit);
4506 }
4507 
4509  ArrayRef<Value *> Args, const SimplifyQuery &Q) {
4510  return ::SimplifyCall(CS, V, Args.begin(), Args.end(), Q, RecursionLimit);
4511 }
4512 
4513 /// See if we can compute a simplified version of this instruction.
4514 /// If not, this returns null.
4515 
4518  const SimplifyQuery Q = SQ.CxtI ? SQ : SQ.getWithInstruction(I);
4519  Value *Result;
4520 
4521  switch (I->getOpcode()) {
4522  default:
4523  Result = ConstantFoldInstruction(I, Q.DL, Q.TLI);
4524  break;
4525  case Instruction::FAdd:
4526  Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
4527  I->getFastMathFlags(), Q);
4528  break;
4529  case Instruction::Add:
4530  Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
4531  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4532  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4533  break;
4534  case Instruction::FSub:
4535  Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
4536  I->getFastMathFlags(), Q);
4537  break;
4538  case Instruction::Sub:
4539  Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
4540  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4541  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4542  break;
4543  case Instruction::FMul:
4544  Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
4545  I->getFastMathFlags(), Q);
4546  break;
4547  case Instruction::Mul:
4548  Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), Q);
4549  break;
4550  case Instruction::SDiv:
4551  Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), Q);
4552  break;
4553  case Instruction::UDiv:
4554  Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), Q);
4555  break;
4556  case Instruction::FDiv:
4557  Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1),
4558  I->getFastMathFlags(), Q);
4559  break;
4560  case Instruction::SRem:
4561  Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), Q);
4562  break;
4563  case Instruction::URem:
4564  Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), Q);
4565  break;
4566  case Instruction::FRem:
4567  Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1),
4568  I->getFastMathFlags(), Q);
4569  break;
4570  case Instruction::Shl:
4571  Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
4572  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4573  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4574  break;
4575  case Instruction::LShr:
4576  Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
4577  cast<BinaryOperator>(I)->isExact(), Q);
4578  break;
4579  case Instruction::AShr:
4580  Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
4581  cast<BinaryOperator>(I)->isExact(), Q);
4582  break;
4583  case Instruction::And:
4584  Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), Q);
4585  break;
4586  case Instruction::Or:
4587  Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), Q);
4588  break;
4589  case Instruction::Xor:
4590  Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), Q);
4591  break;
4592  case Instruction::ICmp:
4593  Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
4594  I->getOperand(0), I->getOperand(1), Q);
4595  break;
4596  case Instruction::FCmp:
4597  Result =
4598  SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(), I->getOperand(0),
4599  I->getOperand(1), I->getFastMathFlags(), Q);
4600  break;
4601  case Instruction::Select:
4602  Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
4603  I->getOperand(2), Q);
4604  break;
4605  case Instruction::GetElementPtr: {
4606  SmallVector<Value *, 8> Ops(I->op_begin(), I->op_end());
4607  Result = SimplifyGEPInst(cast<GetElementPtrInst>(I)->getSourceElementType(),
4608  Ops, Q);
4609  break;
4610  }
4611  case Instruction::InsertValue: {
4612  InsertValueInst *IV = cast<InsertValueInst>(I);
4615  IV->getIndices(), Q);
4616  break;
4617  }
4618  case Instruction::ExtractValue: {
4619  auto *EVI = cast<ExtractValueInst>(I);
4620  Result = SimplifyExtractValueInst(EVI->getAggregateOperand(),
4621  EVI->getIndices(), Q);
4622  break;
4623  }
4624  case Instruction::ExtractElement: {
4625  auto *EEI = cast<ExtractElementInst>(I);
4626  Result = SimplifyExtractElementInst(EEI->getVectorOperand(),
4627  EEI->getIndexOperand(), Q);
4628  break;
4629  }
4630  case Instruction::ShuffleVector: {
4631  auto *SVI = cast<ShuffleVectorInst>(I);
4632  Result = SimplifyShuffleVectorInst(SVI->getOperand(0), SVI->getOperand(1),
4633  SVI->getMask(), SVI->getType(), Q);
4634  break;
4635  }
4636  case Instruction::PHI:
4637  Result = SimplifyPHINode(cast<PHINode>(I), Q);
4638  break;
4639  case Instruction::Call: {
4640  CallSite CS(cast<CallInst>(I));
4641  Result = SimplifyCall(CS, CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
4642  Q);
4643  break;
4644  }
4645 #define HANDLE_CAST_INST(num, opc, clas) case Instruction::opc:
4646 #include "llvm/IR/Instruction.def"
4647 #undef HANDLE_CAST_INST
4648  Result =
4649  SimplifyCastInst(I->getOpcode(), I->getOperand(0), I->getType(), Q);
4650  break;
4651  case Instruction::Alloca:
4652  // No simplifications for Alloca and it can't be constant folded.
4653  Result = nullptr;
4654  break;
4655  }
4656 
4657  // In general, it is possible for computeKnownBits to determine all bits in a
4658  // value even when the operands are not all constants.
4659  if (!Result && I->getType()->isIntOrIntVectorTy()) {
4660  KnownBits Known = computeKnownBits(I, Q.DL, /*Depth*/ 0, Q.AC, I, Q.DT, ORE);
4661  if (Known.isConstant())
4662  Result = ConstantInt::get(I->getType(), Known.getConstant());
4663  }
4664 
4665  /// If called on unreachable code, the above logic may report that the
4666  /// instruction simplified to itself. Make life easier for users by
4667  /// detecting that case here, returning a safe value instead.
4668  return Result == I ? UndefValue::get(I->getType()) : Result;
4669 }
4670 
4671 /// \brief Implementation of recursive simplification through an instruction's
4672 /// uses.
4673 ///
4674 /// This is the common implementation of the recursive simplification routines.
4675 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
4676 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
4677 /// instructions to process and attempt to simplify it using
4678 /// InstructionSimplify.
4679 ///
4680 /// This routine returns 'true' only when *it* simplifies something. The passed
4681 /// in simplified value does not count toward this.
4683  const TargetLibraryInfo *TLI,
4684  const DominatorTree *DT,
4685  AssumptionCache *AC) {
4686  bool Simplified = false;
4688  const DataLayout &DL = I->getModule()->getDataLayout();
4689 
4690  // If we have an explicit value to collapse to, do that round of the
4691  // simplification loop by hand initially.
4692  if (SimpleV) {
4693  for (User *U : I->users())
4694  if (U != I)
4695  Worklist.insert(cast<Instruction>(U));
4696 
4697  // Replace the instruction with its simplified value.
4698  I->replaceAllUsesWith(SimpleV);
4699 
4700  // Gracefully handle edge cases where the instruction is not wired into any
4701  // parent block.
4702  if (I->getParent() && !I->isEHPad() && !isa<TerminatorInst>(I) &&
4703  !I->mayHaveSideEffects())
4704  I->eraseFromParent();
4705  } else {
4706  Worklist.insert(I);
4707  }
4708 
4709  // Note that we must test the size on each iteration, the worklist can grow.
4710  for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
4711  I = Worklist[Idx];
4712 
4713  // See if this instruction simplifies.
4714  SimpleV = SimplifyInstruction(I, {DL, TLI, DT, AC});
4715  if (!SimpleV)
4716  continue;
4717 
4718  Simplified = true;
4719 
4720  // Stash away all the uses of the old instruction so we can check them for
4721  // recursive simplifications after a RAUW. This is cheaper than checking all
4722  // uses of To on the recursive step in most cases.
4723  for (User *U : I->users())
4724  Worklist.insert(cast<Instruction>(U));
4725 
4726  // Replace the instruction with its simplified value.
4727  I->replaceAllUsesWith(SimpleV);
4728 
4729  // Gracefully handle edge cases where the instruction is not wired into any
4730  // parent block.
4731  if (I->getParent() && !I->isEHPad() && !isa<TerminatorInst>(I) &&
4732  !I->mayHaveSideEffects())
4733  I->eraseFromParent();
4734  }
4735  return Simplified;
4736 }
4737 
4739  const TargetLibraryInfo *TLI,
4740  const DominatorTree *DT,
4741  AssumptionCache *AC) {
4742  return replaceAndRecursivelySimplifyImpl(I, nullptr, TLI, DT, AC);
4743 }
4744 
4746  const TargetLibraryInfo *TLI,
4747  const DominatorTree *DT,
4748  AssumptionCache *AC) {
4749  assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
4750  assert(SimpleV && "Must provide a simplified value.");
4751  return replaceAndRecursivelySimplifyImpl(I, SimpleV, TLI, DT, AC);
4752 }
4753 
4754 namespace llvm {
4757  auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
4759  auto *TLI = TLIWP ? &TLIWP->getTLI() : nullptr;
4761  auto *AC = ACWP ? &ACWP->getAssumptionCache(F) : nullptr;
4762  return {F.getParent()->getDataLayout(), TLI, DT, AC};
4763 }
4764 
4766  const DataLayout &DL) {
4767  return {DL, &AR.TLI, &AR.DT, &AR.AC};
4768 }
4769 
4770 template <class T, class... TArgs>
4772  Function &F) {
4773  auto *DT = AM.template getCachedResult<DominatorTreeAnalysis>(F);
4774  auto *TLI = AM.template getCachedResult<TargetLibraryAnalysis>(F);
4775  auto *AC = AM.template getCachedResult<AssumptionAnalysis>(F);
4776  return {F.getParent()->getDataLayout(), TLI, DT, AC};
4777 }
4779  Function &);
4780 }
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
bool getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout &DL, const TargetLibraryInfo *TLI, ObjectSizeOpts Opts={})
Compute the size of the object pointed by Ptr.
bool isFPPredicate() const
Definition: InstrTypes.h:951
Type * getVectorElementType() const
Definition: Type.h:368
BinaryOp_match< LHS, RHS, Instruction::And > m_And(const LHS &L, const RHS &R)
Definition: PatternMatch.h:550
uint64_t CallInst * C
Value * SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, const SimplifyQuery &Q)
Given operands for an ICmpInst, fold the result or return null.
static Value * SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, const SimplifyQuery &Q, unsigned MaxRecurse)
Given operands for an AShr, see if we can fold the result.
BinOpPred_match< LHS, RHS, is_right_shift_op > m_Shr(const LHS &L, const RHS &R)
Matches logical shift operations.
Definition: PatternMatch.h:734
SymbolTableList< Instruction >::iterator eraseFromParent()
This method unlinks &#39;this&#39; from the containing basic block and deletes it.
Definition: Instruction.cpp:69
bool hasNoInfs() const
Determine whether the no-infs flag is set.
unsigned Log2_32_Ceil(uint32_t Value)
Return the ceil log base 2 of the specified value, 32 if the value is zero.
Definition: MathExtras.h:544
A parsed version of the target data layout string in and methods for querying it. ...
Definition: DataLayout.h:109
static ConstantInt * getFalse(LLVMContext &Context)
Definition: Constants.cpp:523
bool isKnownToBeAPowerOfTwo(const Value *V, const DataLayout &DL, bool OrZero=false, unsigned Depth=0, AssumptionCache *AC=nullptr, const Instruction *CxtI=nullptr, const DominatorTree *DT=nullptr)
Return true if the given value is known to have exactly one bit set when defined. ...
class_match< Value > m_Value()
Match an arbitrary value and ignore it.
Definition: PatternMatch.h:72
This class is the base class for the comparison instructions.
Definition: InstrTypes.h:850
class_match< UndefValue > m_Undef()
Match an arbitrary undef constant.
Definition: PatternMatch.h:88
static GCMetadataPrinterRegistry::Add< ErlangGCPrinter > X("erlang", "erlang-compatible garbage collector")
static Value * SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse)
Given operands for an SRem, see if we can fold the result.
bool isSignMask() const
Check if the APInt&#39;s value is returned by getSignMask.
Definition: APInt.h:466
bool isZero() const
Definition: APFloat.h:1128
This instruction extracts a struct member or array element value from an aggregate value...
static Value * SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse)
Given operands for a Mul, see if we can fold the result.
static APInt getAllOnesValue(unsigned numBits)
Get the all-ones value.
Definition: APInt.h:555
This class represents an incoming formal argument to a Function.
Definition: Argument.h:30
const T & back() const
back - Get the last element.
Definition: ArrayRef.h:158
BinaryOp_match< LHS, RHS, Instruction::Sub > m_Sub(const LHS &L, const RHS &R)
Definition: PatternMatch.h:490
bool noNaNs() const
Flag queries.
Definition: Operator.h:189
Value * getAggregateOperand()
Value * SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, FastMathFlags FMF, const SimplifyQuery &Q)
Given operands for an FCmpInst, fold the result or return null.
static const Value * getFNegArgument(const Value *BinOp)
static Type * makeCmpResultType(Type *opnd_type)
Create a result type for fcmp/icmp.
Definition: InstrTypes.h:1074
Value * findScalarElement(Value *V, unsigned EltNo)
Given a vector and an element number, see if the scalar value is already around as a register...
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
SimplifyQuery getWithInstruction(Instruction *I) const
BinaryOps getOpcode() const
Definition: InstrTypes.h:523
BinaryOp_match< LHS, RHS, Instruction::Xor, true > m_c_Xor(const LHS &L, const RHS &R)
Matches an Xor with LHS and RHS in either order.
size_type size() const
Determine the number of elements in the SetVector.
Definition: SetVector.h:78
static Value * SimplifyCastInst(unsigned, Value *, Type *, const SimplifyQuery &, unsigned)
static Value * SimplifyRightShift(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1, bool isExact, const SimplifyQuery &Q, unsigned MaxRecurse)
Given operands for an Shl, LShr or AShr, see if we can fold the result.
static Constant * getGetElementPtr(Type *Ty, Constant *C, ArrayRef< Constant *> IdxList, bool InBounds=false, Optional< unsigned > InRangeIndex=None, Type *OnlyIfReducedTy=nullptr)
Getelementptr form.
Definition: Constants.h:1115
bool isSized(SmallPtrSetImpl< Type *> *Visited=nullptr) const
Return true if it makes sense to take the size of this type.
Definition: Type.h:262
iterator begin() const
Definition: ArrayRef.h:137
LLVM_ATTRIBUTE_ALWAYS_INLINE size_type size() const
Definition: SmallVector.h:136
APInt sdiv(const APInt &RHS) const
Signed division function for APInt.
Definition: APInt.cpp:1590
BinaryOp_match< LHS, RHS, Instruction::SRem > m_SRem(const LHS &L, const RHS &R)
Definition: PatternMatch.h:538
match_zero m_Zero()
Match an arbitrary zero/null constant.
Definition: PatternMatch.h:145
This class represents zero extension of integer types.
static Value * simplifyOrOfICmps(ICmpInst *Op0, ICmpInst *Op1)
const Instruction * CxtI
static Value * SimplifyCall(ImmutableCallSite CS, Value *V, IterTy ArgBegin, IterTy ArgEnd, const SimplifyQuery &Q, unsigned MaxRecurse)
BinaryOp_match< LHS, RHS, Instruction::Mul > m_Mul(const LHS &L, const RHS &R)
Definition: PatternMatch.h:502
APInt zext(unsigned width) const
Zero extend to a new width.
Definition: APInt.cpp:865
Constant * ConstantFoldExtractElementInstruction(Constant *Val, Constant *Idx)
Attempt to constant fold an extractelement instruction with the specified operands and indices...
constexpr T getValueOr(U &&value) const LLVM_LVALUE_FUNCTION
Definition: Optional.h:140
APInt udiv(const APInt &RHS) const
Unsigned division operation.
Definition: APInt.cpp:1519
static Value * simplifyUnsignedRangeCheck(ICmpInst *ZeroICmp, ICmpInst *UnsignedICmp, bool IsAnd)
Commuted variants are assumed to be handled by calling this function again with the parameters swappe...
An immutable pass that tracks lazily created AssumptionCache objects.
static PointerType * get(Type *ElementType, unsigned AddressSpace)
This constructs a pointer to an object of the specified type in a numbered address space...
Definition: Type.cpp:617
static uint64_t round(uint64_t Acc, uint64_t Input)
Definition: xxhash.cpp:57
const Value * getTrueValue() const