LLVM  7.0.0svn
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);
66  unsigned);
67 
68 /// For a boolean type or a vector of boolean type, return false or a vector
69 /// with every element false.
70 static Constant *getFalse(Type *Ty) {
71  return ConstantInt::getFalse(Ty);
72 }
73 
74 /// For a boolean type or a vector of boolean type, return true or a vector
75 /// with every element true.
76 static Constant *getTrue(Type *Ty) {
77  return ConstantInt::getTrue(Ty);
78 }
79 
80 /// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
81 static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
82  Value *RHS) {
83  CmpInst *Cmp = dyn_cast<CmpInst>(V);
84  if (!Cmp)
85  return false;
86  CmpInst::Predicate CPred = Cmp->getPredicate();
87  Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
88  if (CPred == Pred && CLHS == LHS && CRHS == RHS)
89  return true;
90  return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
91  CRHS == LHS;
92 }
93 
94 /// Does the given value dominate the specified phi node?
95 static bool valueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
97  if (!I)
98  // Arguments and constants dominate all instructions.
99  return true;
100 
101  // If we are processing instructions (and/or basic blocks) that have not been
102  // fully added to a function, the parent nodes may still be null. Simply
103  // return the conservative answer in these cases.
104  if (!I->getParent() || !P->getParent() || !I->getFunction())
105  return false;
106 
107  // If we have a DominatorTree then do a precise test.
108  if (DT)
109  return DT->dominates(I, P);
110 
111  // Otherwise, if the instruction is in the entry block and is not an invoke,
112  // then it obviously dominates all phi nodes.
113  if (I->getParent() == &I->getFunction()->getEntryBlock() &&
114  !isa<InvokeInst>(I))
115  return true;
116 
117  return false;
118 }
119 
120 /// Simplify "A op (B op' C)" by distributing op over op', turning it into
121 /// "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
122 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
123 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
124 /// Returns the simplified value, or null if no simplification was performed.
126  Instruction::BinaryOps OpcodeToExpand,
127  const SimplifyQuery &Q, unsigned MaxRecurse) {
128  // Recursion is always used, so bail out at once if we already hit the limit.
129  if (!MaxRecurse--)
130  return nullptr;
131 
132  // Check whether the expression has the form "(A op' B) op C".
133  if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
134  if (Op0->getOpcode() == OpcodeToExpand) {
135  // It does! Try turning it into "(A op C) op' (B op C)".
136  Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
137  // Do "A op C" and "B op C" both simplify?
138  if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
139  if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
140  // They do! Return "L op' R" if it simplifies or is already available.
141  // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
142  if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
143  && L == B && R == A)) {
144  ++NumExpand;
145  return LHS;
146  }
147  // Otherwise return "L op' R" if it simplifies.
148  if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
149  ++NumExpand;
150  return V;
151  }
152  }
153  }
154 
155  // Check whether the expression has the form "A op (B op' C)".
156  if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
157  if (Op1->getOpcode() == OpcodeToExpand) {
158  // It does! Try turning it into "(A op B) op' (A op C)".
159  Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
160  // Do "A op B" and "A op C" both simplify?
161  if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
162  if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
163  // They do! Return "L op' R" if it simplifies or is already available.
164  // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
165  if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
166  && L == C && R == B)) {
167  ++NumExpand;
168  return RHS;
169  }
170  // Otherwise return "L op' R" if it simplifies.
171  if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
172  ++NumExpand;
173  return V;
174  }
175  }
176  }
177 
178  return nullptr;
179 }
180 
181 /// Generic simplifications for associative binary operations.
182 /// Returns the simpler value, or null if none was found.
184  Value *LHS, Value *RHS,
185  const SimplifyQuery &Q,
186  unsigned MaxRecurse) {
187  assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
188 
189  // Recursion is always used, so bail out at once if we already hit the limit.
190  if (!MaxRecurse--)
191  return nullptr;
192 
195 
196  // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
197  if (Op0 && Op0->getOpcode() == Opcode) {
198  Value *A = Op0->getOperand(0);
199  Value *B = Op0->getOperand(1);
200  Value *C = RHS;
201 
202  // Does "B op C" simplify?
203  if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
204  // It does! Return "A op V" if it simplifies or is already available.
205  // If V equals B then "A op V" is just the LHS.
206  if (V == B) return LHS;
207  // Otherwise return "A op V" if it simplifies.
208  if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
209  ++NumReassoc;
210  return W;
211  }
212  }
213  }
214 
215  // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
216  if (Op1 && Op1->getOpcode() == Opcode) {
217  Value *A = LHS;
218  Value *B = Op1->getOperand(0);
219  Value *C = Op1->getOperand(1);
220 
221  // Does "A op B" simplify?
222  if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
223  // It does! Return "V op C" if it simplifies or is already available.
224  // If V equals B then "V op C" is just the RHS.
225  if (V == B) return RHS;
226  // Otherwise return "V op C" if it simplifies.
227  if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
228  ++NumReassoc;
229  return W;
230  }
231  }
232  }
233 
234  // The remaining transforms require commutativity as well as associativity.
235  if (!Instruction::isCommutative(Opcode))
236  return nullptr;
237 
238  // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
239  if (Op0 && Op0->getOpcode() == Opcode) {
240  Value *A = Op0->getOperand(0);
241  Value *B = Op0->getOperand(1);
242  Value *C = RHS;
243 
244  // Does "C op A" simplify?
245  if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
246  // It does! Return "V op B" if it simplifies or is already available.
247  // If V equals A then "V op B" is just the LHS.
248  if (V == A) return LHS;
249  // Otherwise return "V op B" if it simplifies.
250  if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
251  ++NumReassoc;
252  return W;
253  }
254  }
255  }
256 
257  // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
258  if (Op1 && Op1->getOpcode() == Opcode) {
259  Value *A = LHS;
260  Value *B = Op1->getOperand(0);
261  Value *C = Op1->getOperand(1);
262 
263  // Does "C op A" simplify?
264  if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
265  // It does! Return "B op V" if it simplifies or is already available.
266  // If V equals C then "B op V" is just the RHS.
267  if (V == C) return RHS;
268  // Otherwise return "B op V" if it simplifies.
269  if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
270  ++NumReassoc;
271  return W;
272  }
273  }
274  }
275 
276  return nullptr;
277 }
278 
279 /// In the case of a binary operation with a select instruction as an operand,
280 /// try to simplify the binop by seeing whether evaluating it on both branches
281 /// of the select results in the same value. Returns the common value if so,
282 /// otherwise returns null.
284  Value *RHS, const SimplifyQuery &Q,
285  unsigned MaxRecurse) {
286  // Recursion is always used, so bail out at once if we already hit the limit.
287  if (!MaxRecurse--)
288  return nullptr;
289 
290  SelectInst *SI;
291  if (isa<SelectInst>(LHS)) {
292  SI = cast<SelectInst>(LHS);
293  } else {
294  assert(isa<SelectInst>(RHS) && "No select instruction operand!");
295  SI = cast<SelectInst>(RHS);
296  }
297 
298  // Evaluate the BinOp on the true and false branches of the select.
299  Value *TV;
300  Value *FV;
301  if (SI == LHS) {
302  TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
303  FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
304  } else {
305  TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
306  FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
307  }
308 
309  // If they simplified to the same value, then return the common value.
310  // If they both failed to simplify then return null.
311  if (TV == FV)
312  return TV;
313 
314  // If one branch simplified to undef, return the other one.
315  if (TV && isa<UndefValue>(TV))
316  return FV;
317  if (FV && isa<UndefValue>(FV))
318  return TV;
319 
320  // If applying the operation did not change the true and false select values,
321  // then the result of the binop is the select itself.
322  if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
323  return SI;
324 
325  // If one branch simplified and the other did not, and the simplified
326  // value is equal to the unsimplified one, return the simplified value.
327  // For example, select (cond, X, X & Z) & Z -> X & Z.
328  if ((FV && !TV) || (TV && !FV)) {
329  // Check that the simplified value has the form "X op Y" where "op" is the
330  // same as the original operation.
331  Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
332  if (Simplified && Simplified->getOpcode() == unsigned(Opcode)) {
333  // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
334  // We already know that "op" is the same as for the simplified value. See
335  // if the operands match too. If so, return the simplified value.
336  Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
337  Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
338  Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
339  if (Simplified->getOperand(0) == UnsimplifiedLHS &&
340  Simplified->getOperand(1) == UnsimplifiedRHS)
341  return Simplified;
342  if (Simplified->isCommutative() &&
343  Simplified->getOperand(1) == UnsimplifiedLHS &&
344  Simplified->getOperand(0) == UnsimplifiedRHS)
345  return Simplified;
346  }
347  }
348 
349  return nullptr;
350 }
351 
352 /// In the case of a comparison with a select instruction, try to simplify the
353 /// comparison by seeing whether both branches of the select result in the same
354 /// value. Returns the common value if so, otherwise returns null.
356  Value *RHS, const SimplifyQuery &Q,
357  unsigned MaxRecurse) {
358  // Recursion is always used, so bail out at once if we already hit the limit.
359  if (!MaxRecurse--)
360  return nullptr;
361 
362  // Make sure the select is on the LHS.
363  if (!isa<SelectInst>(LHS)) {
364  std::swap(LHS, RHS);
365  Pred = CmpInst::getSwappedPredicate(Pred);
366  }
367  assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
368  SelectInst *SI = cast<SelectInst>(LHS);
369  Value *Cond = SI->getCondition();
370  Value *TV = SI->getTrueValue();
371  Value *FV = SI->getFalseValue();
372 
373  // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
374  // Does "cmp TV, RHS" simplify?
375  Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
376  if (TCmp == Cond) {
377  // It not only simplified, it simplified to the select condition. Replace
378  // it with 'true'.
379  TCmp = getTrue(Cond->getType());
380  } else if (!TCmp) {
381  // It didn't simplify. However if "cmp TV, RHS" is equal to the select
382  // condition then we can replace it with 'true'. Otherwise give up.
383  if (!isSameCompare(Cond, Pred, TV, RHS))
384  return nullptr;
385  TCmp = getTrue(Cond->getType());
386  }
387 
388  // Does "cmp FV, RHS" simplify?
389  Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
390  if (FCmp == Cond) {
391  // It not only simplified, it simplified to the select condition. Replace
392  // it with 'false'.
393  FCmp = getFalse(Cond->getType());
394  } else if (!FCmp) {
395  // It didn't simplify. However if "cmp FV, RHS" is equal to the select
396  // condition then we can replace it with 'false'. Otherwise give up.
397  if (!isSameCompare(Cond, Pred, FV, RHS))
398  return nullptr;
399  FCmp = getFalse(Cond->getType());
400  }
401 
402  // If both sides simplified to the same value, then use it as the result of
403  // the original comparison.
404  if (TCmp == FCmp)
405  return TCmp;
406 
407  // The remaining cases only make sense if the select condition has the same
408  // type as the result of the comparison, so bail out if this is not so.
409  if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
410  return nullptr;
411  // If the false value simplified to false, then the result of the compare
412  // is equal to "Cond && TCmp". This also catches the case when the false
413  // value simplified to false and the true value to true, returning "Cond".
414  if (match(FCmp, m_Zero()))
415  if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
416  return V;
417  // If the true value simplified to true, then the result of the compare
418  // is equal to "Cond || FCmp".
419  if (match(TCmp, m_One()))
420  if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
421  return V;
422  // Finally, if the false value simplified to true and the true value to
423  // false, then the result of the compare is equal to "!Cond".
424  if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
425  if (Value *V =
426  SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
427  Q, MaxRecurse))
428  return V;
429 
430  return nullptr;
431 }
432 
433 /// In the case of a binary operation with an operand that is a PHI instruction,
434 /// try to simplify the binop by seeing whether evaluating it on the incoming
435 /// phi values yields the same result for every value. If so returns the common
436 /// value, otherwise returns null.
438  Value *RHS, const SimplifyQuery &Q,
439  unsigned MaxRecurse) {
440  // Recursion is always used, so bail out at once if we already hit the limit.
441  if (!MaxRecurse--)
442  return nullptr;
443 
444  PHINode *PI;
445  if (isa<PHINode>(LHS)) {
446  PI = cast<PHINode>(LHS);
447  // Bail out if RHS and the phi may be mutually interdependent due to a loop.
448  if (!valueDominatesPHI(RHS, PI, Q.DT))
449  return nullptr;
450  } else {
451  assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
452  PI = cast<PHINode>(RHS);
453  // Bail out if LHS and the phi may be mutually interdependent due to a loop.
454  if (!valueDominatesPHI(LHS, PI, Q.DT))
455  return nullptr;
456  }
457 
458  // Evaluate the BinOp on the incoming phi values.
459  Value *CommonValue = nullptr;
460  for (Value *Incoming : PI->incoming_values()) {
461  // If the incoming value is the phi node itself, it can safely be skipped.
462  if (Incoming == PI) continue;
463  Value *V = PI == LHS ?
464  SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
465  SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
466  // If the operation failed to simplify, or simplified to a different value
467  // to previously, then give up.
468  if (!V || (CommonValue && V != CommonValue))
469  return nullptr;
470  CommonValue = V;
471  }
472 
473  return CommonValue;
474 }
475 
476 /// In the case of a comparison with a PHI instruction, try to simplify the
477 /// comparison by seeing whether comparing with all of the incoming phi values
478 /// yields the same result every time. If so returns the common result,
479 /// otherwise returns null.
481  const SimplifyQuery &Q, unsigned MaxRecurse) {
482  // Recursion is always used, so bail out at once if we already hit the limit.
483  if (!MaxRecurse--)
484  return nullptr;
485 
486  // Make sure the phi is on the LHS.
487  if (!isa<PHINode>(LHS)) {
488  std::swap(LHS, RHS);
489  Pred = CmpInst::getSwappedPredicate(Pred);
490  }
491  assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
492  PHINode *PI = cast<PHINode>(LHS);
493 
494  // Bail out if RHS and the phi may be mutually interdependent due to a loop.
495  if (!valueDominatesPHI(RHS, PI, Q.DT))
496  return nullptr;
497 
498  // Evaluate the BinOp on the incoming phi values.
499  Value *CommonValue = nullptr;
500  for (Value *Incoming : PI->incoming_values()) {
501  // If the incoming value is the phi node itself, it can safely be skipped.
502  if (Incoming == PI) continue;
503  Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
504  // If the operation failed to simplify, or simplified to a different value
505  // to previously, then give up.
506  if (!V || (CommonValue && V != CommonValue))
507  return nullptr;
508  CommonValue = V;
509  }
510 
511  return CommonValue;
512 }
513 
515  Value *&Op0, Value *&Op1,
516  const SimplifyQuery &Q) {
517  if (auto *CLHS = dyn_cast<Constant>(Op0)) {
518  if (auto *CRHS = dyn_cast<Constant>(Op1))
519  return ConstantFoldBinaryOpOperands(Opcode, CLHS, CRHS, Q.DL);
520 
521  // Canonicalize the constant to the RHS if this is a commutative operation.
522  if (Instruction::isCommutative(Opcode))
523  std::swap(Op0, Op1);
524  }
525  return nullptr;
526 }
527 
528 /// Given operands for an Add, see if we can fold the result.
529 /// If not, this returns null.
530 static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool IsNSW, bool IsNUW,
531  const SimplifyQuery &Q, unsigned MaxRecurse) {
532  if (Constant *C = foldOrCommuteConstant(Instruction::Add, Op0, Op1, Q))
533  return C;
534 
535  // X + undef -> undef
536  if (match(Op1, m_Undef()))
537  return Op1;
538 
539  // X + 0 -> X
540  if (match(Op1, m_Zero()))
541  return Op0;
542 
543  // If two operands are negative, return 0.
544  if (isKnownNegation(Op0, Op1))
545  return Constant::getNullValue(Op0->getType());
546 
547  // X + (Y - X) -> Y
548  // (Y - X) + X -> Y
549  // Eg: X + -X -> 0
550  Value *Y = nullptr;
551  if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
552  match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
553  return Y;
554 
555  // X + ~X -> -1 since ~X = -X-1
556  Type *Ty = Op0->getType();
557  if (match(Op0, m_Not(m_Specific(Op1))) ||
558  match(Op1, m_Not(m_Specific(Op0))))
559  return Constant::getAllOnesValue(Ty);
560 
561  // add nsw/nuw (xor Y, signmask), signmask --> Y
562  // The no-wrapping add guarantees that the top bit will be set by the add.
563  // Therefore, the xor must be clearing the already set sign bit of Y.
564  if ((IsNSW || IsNUW) && match(Op1, m_SignMask()) &&
565  match(Op0, m_Xor(m_Value(Y), m_SignMask())))
566  return Y;
567 
568  // add nuw %x, -1 -> -1, because %x can only be 0.
569  if (IsNUW && match(Op1, m_AllOnes()))
570  return Op1; // Which is -1.
571 
572  /// i1 add -> xor.
573  if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
574  if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
575  return V;
576 
577  // Try some generic simplifications for associative operations.
578  if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
579  MaxRecurse))
580  return V;
581 
582  // Threading Add over selects and phi nodes is pointless, so don't bother.
583  // Threading over the select in "A + select(cond, B, C)" means evaluating
584  // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
585  // only if B and C are equal. If B and C are equal then (since we assume
586  // that operands have already been simplified) "select(cond, B, C)" should
587  // have been simplified to the common value of B and C already. Analysing
588  // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
589  // for threading over phi nodes.
590 
591  return nullptr;
592 }
593 
594 Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool IsNSW, bool IsNUW,
595  const SimplifyQuery &Query) {
596  return ::SimplifyAddInst(Op0, Op1, IsNSW, IsNUW, Query, RecursionLimit);
597 }
598 
599 /// Compute the base pointer and cumulative constant offsets for V.
600 ///
601 /// This strips all constant offsets off of V, leaving it the base pointer, and
602 /// accumulates the total constant offset applied in the returned constant. It
603 /// returns 0 if V is not a pointer, and returns the constant '0' if there are
604 /// no constant offsets applied.
605 ///
606 /// This is very similar to GetPointerBaseWithConstantOffset except it doesn't
607 /// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc.
608 /// folding.
610  bool AllowNonInbounds = false) {
612 
613  Type *IntPtrTy = DL.getIntPtrType(V->getType())->getScalarType();
614  APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());
615 
616  // Even though we don't look through PHI nodes, we could be called on an
617  // instruction in an unreachable block, which may be on a cycle.
618  SmallPtrSet<Value *, 4> Visited;
619  Visited.insert(V);
620  do {
621  if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
622  if ((!AllowNonInbounds && !GEP->isInBounds()) ||
623  !GEP->accumulateConstantOffset(DL, Offset))
624  break;
625  V = GEP->getPointerOperand();
626  } else if (Operator::getOpcode(V) == Instruction::BitCast) {
627  V = cast<Operator>(V)->getOperand(0);
628  } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
629  if (GA->isInterposable())
630  break;
631  V = GA->getAliasee();
632  } else {
633  if (auto CS = CallSite(V))
634  if (Value *RV = CS.getReturnedArgOperand()) {
635  V = RV;
636  continue;
637  }
638  break;
639  }
640  assert(V->getType()->isPtrOrPtrVectorTy() && "Unexpected operand type!");
641  } while (Visited.insert(V).second);
642 
643  Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
644  if (V->getType()->isVectorTy())
646  OffsetIntPtr);
647  return OffsetIntPtr;
648 }
649 
650 /// Compute the constant difference between two pointer values.
651 /// If the difference is not a constant, returns zero.
653  Value *RHS) {
654  Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
655  Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
656 
657  // If LHS and RHS are not related via constant offsets to the same base
658  // value, there is nothing we can do here.
659  if (LHS != RHS)
660  return nullptr;
661 
662  // Otherwise, the difference of LHS - RHS can be computed as:
663  // LHS - RHS
664  // = (LHSOffset + Base) - (RHSOffset + Base)
665  // = LHSOffset - RHSOffset
666  return ConstantExpr::getSub(LHSOffset, RHSOffset);
667 }
668 
669 /// Given operands for a Sub, see if we can fold the result.
670 /// If not, this returns null.
671 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
672  const SimplifyQuery &Q, unsigned MaxRecurse) {
673  if (Constant *C = foldOrCommuteConstant(Instruction::Sub, Op0, Op1, Q))
674  return C;
675 
676  // X - undef -> undef
677  // undef - X -> undef
678  if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
679  return UndefValue::get(Op0->getType());
680 
681  // X - 0 -> X
682  if (match(Op1, m_Zero()))
683  return Op0;
684 
685  // X - X -> 0
686  if (Op0 == Op1)
687  return Constant::getNullValue(Op0->getType());
688 
689  // Is this a negation?
690  if (match(Op0, m_Zero())) {
691  // 0 - X -> 0 if the sub is NUW.
692  if (isNUW)
693  return Constant::getNullValue(Op0->getType());
694 
695  KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
696  if (Known.Zero.isMaxSignedValue()) {
697  // Op1 is either 0 or the minimum signed value. If the sub is NSW, then
698  // Op1 must be 0 because negating the minimum signed value is undefined.
699  if (isNSW)
700  return Constant::getNullValue(Op0->getType());
701 
702  // 0 - X -> X if X is 0 or the minimum signed value.
703  return Op1;
704  }
705  }
706 
707  // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
708  // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
709  Value *X = nullptr, *Y = nullptr, *Z = Op1;
710  if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
711  // See if "V === Y - Z" simplifies.
712  if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
713  // It does! Now see if "X + V" simplifies.
714  if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
715  // It does, we successfully reassociated!
716  ++NumReassoc;
717  return W;
718  }
719  // See if "V === X - Z" simplifies.
720  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
721  // It does! Now see if "Y + V" simplifies.
722  if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
723  // It does, we successfully reassociated!
724  ++NumReassoc;
725  return W;
726  }
727  }
728 
729  // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
730  // For example, X - (X + 1) -> -1
731  X = Op0;
732  if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
733  // See if "V === X - Y" simplifies.
734  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
735  // It does! Now see if "V - Z" simplifies.
736  if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
737  // It does, we successfully reassociated!
738  ++NumReassoc;
739  return W;
740  }
741  // See if "V === X - Z" simplifies.
742  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
743  // It does! Now see if "V - Y" simplifies.
744  if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
745  // It does, we successfully reassociated!
746  ++NumReassoc;
747  return W;
748  }
749  }
750 
751  // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
752  // For example, X - (X - Y) -> Y.
753  Z = Op0;
754  if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
755  // See if "V === Z - X" simplifies.
756  if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
757  // It does! Now see if "V + Y" simplifies.
758  if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
759  // It does, we successfully reassociated!
760  ++NumReassoc;
761  return W;
762  }
763 
764  // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
765  if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
766  match(Op1, m_Trunc(m_Value(Y))))
767  if (X->getType() == Y->getType())
768  // See if "V === X - Y" simplifies.
769  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
770  // It does! Now see if "trunc V" simplifies.
771  if (Value *W = SimplifyCastInst(Instruction::Trunc, V, Op0->getType(),
772  Q, MaxRecurse - 1))
773  // It does, return the simplified "trunc V".
774  return W;
775 
776  // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
777  if (match(Op0, m_PtrToInt(m_Value(X))) &&
778  match(Op1, m_PtrToInt(m_Value(Y))))
780  return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
781 
782  // i1 sub -> xor.
783  if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
784  if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
785  return V;
786 
787  // Threading Sub over selects and phi nodes is pointless, so don't bother.
788  // Threading over the select in "A - select(cond, B, C)" means evaluating
789  // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
790  // only if B and C are equal. If B and C are equal then (since we assume
791  // that operands have already been simplified) "select(cond, B, C)" should
792  // have been simplified to the common value of B and C already. Analysing
793  // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
794  // for threading over phi nodes.
795 
796  return nullptr;
797 }
798 
799 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
800  const SimplifyQuery &Q) {
801  return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit);
802 }
803 
804 /// Given operands for a Mul, see if we can fold the result.
805 /// If not, this returns null.
806 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
807  unsigned MaxRecurse) {
808  if (Constant *C = foldOrCommuteConstant(Instruction::Mul, Op0, Op1, Q))
809  return C;
810 
811  // X * undef -> 0
812  // X * 0 -> 0
813  if (match(Op1, m_CombineOr(m_Undef(), m_Zero())))
814  return Constant::getNullValue(Op0->getType());
815 
816  // X * 1 -> X
817  if (match(Op1, m_One()))
818  return Op0;
819 
820  // (X / Y) * Y -> X if the division is exact.
821  Value *X = nullptr;
822  if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
823  match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
824  return X;
825 
826  // i1 mul -> and.
827  if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
828  if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
829  return V;
830 
831  // Try some generic simplifications for associative operations.
832  if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
833  MaxRecurse))
834  return V;
835 
836  // Mul distributes over Add. Try some generic simplifications based on this.
837  if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
838  Q, MaxRecurse))
839  return V;
840 
841  // If the operation is with the result of a select instruction, check whether
842  // operating on either branch of the select always yields the same value.
843  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
844  if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
845  MaxRecurse))
846  return V;
847 
848  // If the operation is with the result of a phi instruction, check whether
849  // operating on all incoming values of the phi always yields the same value.
850  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
851  if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
852  MaxRecurse))
853  return V;
854 
855  return nullptr;
856 }
857 
860 }
861 
862 /// Check for common or similar folds of integer division or integer remainder.
863 /// This applies to all 4 opcodes (sdiv/udiv/srem/urem).
864 static Value *simplifyDivRem(Value *Op0, Value *Op1, bool IsDiv) {
865  Type *Ty = Op0->getType();
866 
867  // X / undef -> undef
868  // X % undef -> undef
869  if (match(Op1, m_Undef()))
870  return Op1;
871 
872  // X / 0 -> undef
873  // X % 0 -> undef
874  // We don't need to preserve faults!
875  if (match(Op1, m_Zero()))
876  return UndefValue::get(Ty);
877 
878  // If any element of a constant divisor vector is zero or undef, the whole op
879  // is undef.
880  auto *Op1C = dyn_cast<Constant>(Op1);
881  if (Op1C && Ty->isVectorTy()) {
882  unsigned NumElts = Ty->getVectorNumElements();
883  for (unsigned i = 0; i != NumElts; ++i) {
884  Constant *Elt = Op1C->getAggregateElement(i);
885  if (Elt && (Elt->isNullValue() || isa<UndefValue>(Elt)))
886  return UndefValue::get(Ty);
887  }
888  }
889 
890  // undef / X -> 0
891  // undef % X -> 0
892  if (match(Op0, m_Undef()))
893  return Constant::getNullValue(Ty);
894 
895  // 0 / X -> 0
896  // 0 % X -> 0
897  if (match(Op0, m_Zero()))
898  return Constant::getNullValue(Op0->getType());
899 
900  // X / X -> 1
901  // X % X -> 0
902  if (Op0 == Op1)
903  return IsDiv ? ConstantInt::get(Ty, 1) : Constant::getNullValue(Ty);
904 
905  // X / 1 -> X
906  // X % 1 -> 0
907  // If this is a boolean op (single-bit element type), we can't have
908  // division-by-zero or remainder-by-zero, so assume the divisor is 1.
909  // Similarly, if we're zero-extending a boolean divisor, then assume it's a 1.
910  Value *X;
911  if (match(Op1, m_One()) || Ty->isIntOrIntVectorTy(1) ||
912  (match(Op1, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)))
913  return IsDiv ? Op0 : Constant::getNullValue(Ty);
914 
915  return nullptr;
916 }
917 
918 /// Given a predicate and two operands, return true if the comparison is true.
919 /// This is a helper for div/rem simplification where we return some other value
920 /// when we can prove a relationship between the operands.
921 static bool isICmpTrue(ICmpInst::Predicate Pred, Value *LHS, Value *RHS,
922  const SimplifyQuery &Q, unsigned MaxRecurse) {
923  Value *V = SimplifyICmpInst(Pred, LHS, RHS, Q, MaxRecurse);
924  Constant *C = dyn_cast_or_null<Constant>(V);
925  return (C && C->isAllOnesValue());
926 }
927 
928 /// Return true if we can simplify X / Y to 0. Remainder can adapt that answer
929 /// to simplify X % Y to X.
930 static bool isDivZero(Value *X, Value *Y, const SimplifyQuery &Q,
931  unsigned MaxRecurse, bool IsSigned) {
932  // Recursion is always used, so bail out at once if we already hit the limit.
933  if (!MaxRecurse--)
934  return false;
935 
936  if (IsSigned) {
937  // |X| / |Y| --> 0
938  //
939  // We require that 1 operand is a simple constant. That could be extended to
940  // 2 variables if we computed the sign bit for each.
941  //
942  // Make sure that a constant is not the minimum signed value because taking
943  // the abs() of that is undefined.
944  Type *Ty = X->getType();
945  const APInt *C;
946  if (match(X, m_APInt(C)) && !C->isMinSignedValue()) {
947  // Is the variable divisor magnitude always greater than the constant
948  // dividend magnitude?
949  // |Y| > |C| --> Y < -abs(C) or Y > abs(C)
950  Constant *PosDividendC = ConstantInt::get(Ty, C->abs());
951  Constant *NegDividendC = ConstantInt::get(Ty, -C->abs());
952  if (isICmpTrue(CmpInst::ICMP_SLT, Y, NegDividendC, Q, MaxRecurse) ||
953  isICmpTrue(CmpInst::ICMP_SGT, Y, PosDividendC, Q, MaxRecurse))
954  return true;
955  }
956  if (match(Y, m_APInt(C))) {
957  // Special-case: we can't take the abs() of a minimum signed value. If
958  // that's the divisor, then all we have to do is prove that the dividend
959  // is also not the minimum signed value.
960  if (C->isMinSignedValue())
961  return isICmpTrue(CmpInst::ICMP_NE, X, Y, Q, MaxRecurse);
962 
963  // Is the variable dividend magnitude always less than the constant
964  // divisor magnitude?
965  // |X| < |C| --> X > -abs(C) and X < abs(C)
966  Constant *PosDivisorC = ConstantInt::get(Ty, C->abs());
967  Constant *NegDivisorC = ConstantInt::get(Ty, -C->abs());
968  if (isICmpTrue(CmpInst::ICMP_SGT, X, NegDivisorC, Q, MaxRecurse) &&
969  isICmpTrue(CmpInst::ICMP_SLT, X, PosDivisorC, Q, MaxRecurse))
970  return true;
971  }
972  return false;
973  }
974 
975  // IsSigned == false.
976  // Is the dividend unsigned less than the divisor?
977  return isICmpTrue(ICmpInst::ICMP_ULT, X, Y, Q, MaxRecurse);
978 }
979 
980 /// These are simplifications common to SDiv and UDiv.
982  const SimplifyQuery &Q, unsigned MaxRecurse) {
983  if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
984  return C;
985 
986  if (Value *V = simplifyDivRem(Op0, Op1, true))
987  return V;
988 
989  bool IsSigned = Opcode == Instruction::SDiv;
990 
991  // (X * Y) / Y -> X if the multiplication does not overflow.
992  Value *X;
993  if (match(Op0, m_c_Mul(m_Value(X), m_Specific(Op1)))) {
994  auto *Mul = cast<OverflowingBinaryOperator>(Op0);
995  // If the Mul does not overflow, then we are good to go.
996  if ((IsSigned && Mul->hasNoSignedWrap()) ||
997  (!IsSigned && Mul->hasNoUnsignedWrap()))
998  return X;
999  // If X has the form X = A / Y, then X * Y cannot overflow.
1000  if ((IsSigned && match(X, m_SDiv(m_Value(), m_Specific(Op1)))) ||
1001  (!IsSigned && match(X, m_UDiv(m_Value(), m_Specific(Op1)))))
1002  return X;
1003  }
1004 
1005  // (X rem Y) / Y -> 0
1006  if ((IsSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1007  (!IsSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1008  return Constant::getNullValue(Op0->getType());
1009 
1010  // (X /u C1) /u C2 -> 0 if C1 * C2 overflow
1011  ConstantInt *C1, *C2;
1012  if (!IsSigned && match(Op0, m_UDiv(m_Value(X), m_ConstantInt(C1))) &&
1013  match(Op1, m_ConstantInt(C2))) {
1014  bool Overflow;
1015  (void)C1->getValue().umul_ov(C2->getValue(), Overflow);
1016  if (Overflow)
1017  return Constant::getNullValue(Op0->getType());
1018  }
1019 
1020  // If the operation is with the result of a select instruction, check whether
1021  // operating on either branch of the select always yields the same value.
1022  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1023  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1024  return V;
1025 
1026  // If the operation is with the result of a phi instruction, check whether
1027  // operating on all incoming values of the phi always yields the same value.
1028  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1029  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1030  return V;
1031 
1032  if (isDivZero(Op0, Op1, Q, MaxRecurse, IsSigned))
1033  return Constant::getNullValue(Op0->getType());
1034 
1035  return nullptr;
1036 }
1037 
1038 /// These are simplifications common to SRem and URem.
1040  const SimplifyQuery &Q, unsigned MaxRecurse) {
1041  if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1042  return C;
1043 
1044  if (Value *V = simplifyDivRem(Op0, Op1, false))
1045  return V;
1046 
1047  // (X % Y) % Y -> X % Y
1048  if ((Opcode == Instruction::SRem &&
1049  match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1050  (Opcode == Instruction::URem &&
1051  match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1052  return Op0;
1053 
1054  // (X << Y) % X -> 0
1055  if ((Opcode == Instruction::SRem &&
1056  match(Op0, m_NSWShl(m_Specific(Op1), m_Value()))) ||
1057  (Opcode == Instruction::URem &&
1058  match(Op0, m_NUWShl(m_Specific(Op1), m_Value()))))
1059  return Constant::getNullValue(Op0->getType());
1060 
1061  // If the operation is with the result of a select instruction, check whether
1062  // operating on either branch of the select always yields the same value.
1063  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1064  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1065  return V;
1066 
1067  // If the operation is with the result of a phi instruction, check whether
1068  // operating on all incoming values of the phi always yields the same value.
1069  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1070  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1071  return V;
1072 
1073  // If X / Y == 0, then X % Y == X.
1074  if (isDivZero(Op0, Op1, Q, MaxRecurse, Opcode == Instruction::SRem))
1075  return Op0;
1076 
1077  return nullptr;
1078 }
1079 
1080 /// Given operands for an SDiv, see if we can fold the result.
1081 /// If not, this returns null.
1082 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1083  unsigned MaxRecurse) {
1084  return simplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse);
1085 }
1086 
1089 }
1090 
1091 /// Given operands for a UDiv, see if we can fold the result.
1092 /// If not, this returns null.
1093 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1094  unsigned MaxRecurse) {
1095  return simplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse);
1096 }
1097 
1100 }
1101 
1102 /// Given operands for an SRem, see if we can fold the result.
1103 /// If not, this returns null.
1104 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1105  unsigned MaxRecurse) {
1106  // If the divisor is 0, the result is undefined, so assume the divisor is -1.
1107  // srem Op0, (sext i1 X) --> srem Op0, -1 --> 0
1108  Value *X;
1109  if (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1))
1110  return ConstantInt::getNullValue(Op0->getType());
1111 
1112  // If the two operands are negated, return 0.
1113  if (isKnownNegation(Op0, Op1))
1114  return ConstantInt::getNullValue(Op0->getType());
1115 
1116  return simplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse);
1117 }
1118 
1121 }
1122 
1123 /// Given operands for a URem, see if we can fold the result.
1124 /// If not, this returns null.
1125 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1126  unsigned MaxRecurse) {
1127  return simplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse);
1128 }
1129 
1132 }
1133 
1134 /// Returns true if a shift by \c Amount always yields undef.
1135 static bool isUndefShift(Value *Amount) {
1136  Constant *C = dyn_cast<Constant>(Amount);
1137  if (!C)
1138  return false;
1139 
1140  // X shift by undef -> undef because it may shift by the bitwidth.
1141  if (isa<UndefValue>(C))
1142  return true;
1143 
1144  // Shifting by the bitwidth or more is undefined.
1145  if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
1146  if (CI->getValue().getLimitedValue() >=
1147  CI->getType()->getScalarSizeInBits())
1148  return true;
1149 
1150  // If all lanes of a vector shift are undefined the whole shift is.
1151  if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) {
1152  for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I)
1154  return false;
1155  return true;
1156  }
1157 
1158  return false;
1159 }
1160 
1161 /// Given operands for an Shl, LShr or AShr, see if we can fold the result.
1162 /// If not, this returns null.
1164  Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse) {
1165  if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1166  return C;
1167 
1168  // 0 shift by X -> 0
1169  if (match(Op0, m_Zero()))
1170  return Constant::getNullValue(Op0->getType());
1171 
1172  // X shift by 0 -> X
1173  // Shift-by-sign-extended bool must be shift-by-0 because shift-by-all-ones
1174  // would be poison.
1175  Value *X;
1176  if (match(Op1, m_Zero()) ||
1177  (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)))
1178  return Op0;
1179 
1180  // Fold undefined shifts.
1181  if (isUndefShift(Op1))
1182  return UndefValue::get(Op0->getType());
1183 
1184  // If the operation is with the result of a select instruction, check whether
1185  // operating on either branch of the select always yields the same value.
1186  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1187  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1188  return V;
1189 
1190  // If the operation is with the result of a phi instruction, check whether
1191  // operating on all incoming values of the phi always yields the same value.
1192  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1193  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1194  return V;
1195 
1196  // If any bits in the shift amount make that value greater than or equal to
1197  // the number of bits in the type, the shift is undefined.
1198  KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1199  if (Known.One.getLimitedValue() >= Known.getBitWidth())
1200  return UndefValue::get(Op0->getType());
1201 
1202  // If all valid bits in the shift amount are known zero, the first operand is
1203  // unchanged.
1204  unsigned NumValidShiftBits = Log2_32_Ceil(Known.getBitWidth());
1205  if (Known.countMinTrailingZeros() >= NumValidShiftBits)
1206  return Op0;
1207 
1208  return nullptr;
1209 }
1210 
1211 /// Given operands for an Shl, LShr or AShr, see if we can
1212 /// fold the result. If not, this returns null.
1214  Value *Op1, bool isExact, const SimplifyQuery &Q,
1215  unsigned MaxRecurse) {
1216  if (Value *V = SimplifyShift(Opcode, Op0, Op1, Q, MaxRecurse))
1217  return V;
1218 
1219  // X >> X -> 0
1220  if (Op0 == Op1)
1221  return Constant::getNullValue(Op0->getType());
1222 
1223  // undef >> X -> 0
1224  // undef >> X -> undef (if it's exact)
1225  if (match(Op0, m_Undef()))
1226  return isExact ? Op0 : Constant::getNullValue(Op0->getType());
1227 
1228  // The low bit cannot be shifted out of an exact shift if it is set.
1229  if (isExact) {
1230  KnownBits Op0Known = computeKnownBits(Op0, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT);
1231  if (Op0Known.One[0])
1232  return Op0;
1233  }
1234 
1235  return nullptr;
1236 }
1237 
1238 /// Given operands for an Shl, see if we can fold the result.
1239 /// If not, this returns null.
1240 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1241  const SimplifyQuery &Q, unsigned MaxRecurse) {
1242  if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1243  return V;
1244 
1245  // undef << X -> 0
1246  // undef << X -> undef if (if it's NSW/NUW)
1247  if (match(Op0, m_Undef()))
1248  return isNSW || isNUW ? Op0 : Constant::getNullValue(Op0->getType());
1249 
1250  // (X >> A) << A -> X
1251  Value *X;
1252  if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1253  return X;
1254 
1255  // shl nuw i8 C, %x -> C iff C has sign bit set.
1256  if (isNUW && match(Op0, m_Negative()))
1257  return Op0;
1258  // NOTE: could use computeKnownBits() / LazyValueInfo,
1259  // but the cost-benefit analysis suggests it isn't worth it.
1260 
1261  return nullptr;
1262 }
1263 
1264 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1265  const SimplifyQuery &Q) {
1266  return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit);
1267 }
1268 
1269 /// Given operands for an LShr, see if we can fold the result.
1270 /// If not, this returns null.
1271 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1272  const SimplifyQuery &Q, unsigned MaxRecurse) {
1273  if (Value *V = SimplifyRightShift(Instruction::LShr, Op0, Op1, isExact, Q,
1274  MaxRecurse))
1275  return V;
1276 
1277  // (X << A) >> A -> X
1278  Value *X;
1279  if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1))))
1280  return X;
1281 
1282  return nullptr;
1283 }
1284 
1285 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1286  const SimplifyQuery &Q) {
1287  return ::SimplifyLShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1288 }
1289 
1290 /// Given operands for an AShr, see if we can fold the result.
1291 /// If not, this returns null.
1292 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1293  const SimplifyQuery &Q, unsigned MaxRecurse) {
1294  if (Value *V = SimplifyRightShift(Instruction::AShr, Op0, Op1, isExact, Q,
1295  MaxRecurse))
1296  return V;
1297 
1298  // all ones >>a X -> -1
1299  // Do not return Op0 because it may contain undef elements if it's a vector.
1300  if (match(Op0, m_AllOnes()))
1301  return Constant::getAllOnesValue(Op0->getType());
1302 
1303  // (X << A) >> A -> X
1304  Value *X;
1305  if (match(Op0, m_NSWShl(m_Value(X), m_Specific(Op1))))
1306  return X;
1307 
1308  // Arithmetic shifting an all-sign-bit value is a no-op.
1309  unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1310  if (NumSignBits == Op0->getType()->getScalarSizeInBits())
1311  return Op0;
1312 
1313  return nullptr;
1314 }
1315 
1316 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1317  const SimplifyQuery &Q) {
1318  return ::SimplifyAShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1319 }
1320 
1321 /// Commuted variants are assumed to be handled by calling this function again
1322 /// with the parameters swapped.
1324  ICmpInst *UnsignedICmp, bool IsAnd) {
1325  Value *X, *Y;
1326 
1327  ICmpInst::Predicate EqPred;
1328  if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) ||
1329  !ICmpInst::isEquality(EqPred))
1330  return nullptr;
1331 
1332  ICmpInst::Predicate UnsignedPred;
1333  if (match(UnsignedICmp, m_ICmp(UnsignedPred, m_Value(X), m_Specific(Y))) &&
1334  ICmpInst::isUnsigned(UnsignedPred))
1335  ;
1336  else if (match(UnsignedICmp,
1337  m_ICmp(UnsignedPred, m_Specific(Y), m_Value(X))) &&
1338  ICmpInst::isUnsigned(UnsignedPred))
1339  UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred);
1340  else
1341  return nullptr;
1342 
1343  // X < Y && Y != 0 --> X < Y
1344  // X < Y || Y != 0 --> Y != 0
1345  if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE)
1346  return IsAnd ? UnsignedICmp : ZeroICmp;
1347 
1348  // X >= Y || Y != 0 --> true
1349  // X >= Y || Y == 0 --> X >= Y
1350  if (UnsignedPred == ICmpInst::ICMP_UGE && !IsAnd) {
1351  if (EqPred == ICmpInst::ICMP_NE)
1352  return getTrue(UnsignedICmp->getType());
1353  return UnsignedICmp;
1354  }
1355 
1356  // X < Y && Y == 0 --> false
1357  if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
1358  IsAnd)
1359  return getFalse(UnsignedICmp->getType());
1360 
1361  return nullptr;
1362 }
1363 
1364 /// Commuted variants are assumed to be handled by calling this function again
1365 /// with the parameters swapped.
1367  ICmpInst::Predicate Pred0, Pred1;
1368  Value *A ,*B;
1369  if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
1370  !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
1371  return nullptr;
1372 
1373  // We have (icmp Pred0, A, B) & (icmp Pred1, A, B).
1374  // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1375  // can eliminate Op1 from this 'and'.
1376  if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
1377  return Op0;
1378 
1379  // Check for any combination of predicates that are guaranteed to be disjoint.
1380  if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
1381  (Pred0 == ICmpInst::ICMP_EQ && ICmpInst::isFalseWhenEqual(Pred1)) ||
1382  (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT) ||
1383  (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT))
1384  return getFalse(Op0->getType());
1385 
1386  return nullptr;
1387 }
1388 
1389 /// Commuted variants are assumed to be handled by calling this function again
1390 /// with the parameters swapped.
1392  ICmpInst::Predicate Pred0, Pred1;
1393  Value *A ,*B;
1394  if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
1395  !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
1396  return nullptr;
1397 
1398  // We have (icmp Pred0, A, B) | (icmp Pred1, A, B).
1399  // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1400  // can eliminate Op0 from this 'or'.
1401  if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
1402  return Op1;
1403 
1404  // Check for any combination of predicates that cover the entire range of
1405  // possibilities.
1406  if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
1407  (Pred0 == ICmpInst::ICMP_NE && ICmpInst::isTrueWhenEqual(Pred1)) ||
1408  (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGE) ||
1409  (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGE))
1410  return getTrue(Op0->getType());
1411 
1412  return nullptr;
1413 }
1414 
1415 /// Test if a pair of compares with a shared operand and 2 constants has an
1416 /// empty set intersection, full set union, or if one compare is a superset of
1417 /// the other.
1419  bool IsAnd) {
1420  // Look for this pattern: {and/or} (icmp X, C0), (icmp X, C1)).
1421  if (Cmp0->getOperand(0) != Cmp1->getOperand(0))
1422  return nullptr;
1423 
1424  const APInt *C0, *C1;
1425  if (!match(Cmp0->getOperand(1), m_APInt(C0)) ||
1426  !match(Cmp1->getOperand(1), m_APInt(C1)))
1427  return nullptr;
1428 
1429  auto Range0 = ConstantRange::makeExactICmpRegion(Cmp0->getPredicate(), *C0);
1430  auto Range1 = ConstantRange::makeExactICmpRegion(Cmp1->getPredicate(), *C1);
1431 
1432  // For and-of-compares, check if the intersection is empty:
1433  // (icmp X, C0) && (icmp X, C1) --> empty set --> false
1434  if (IsAnd && Range0.intersectWith(Range1).isEmptySet())
1435  return getFalse(Cmp0->getType());
1436 
1437  // For or-of-compares, check if the union is full:
1438  // (icmp X, C0) || (icmp X, C1) --> full set --> true
1439  if (!IsAnd && Range0.unionWith(Range1).isFullSet())
1440  return getTrue(Cmp0->getType());
1441 
1442  // Is one range a superset of the other?
1443  // If this is and-of-compares, take the smaller set:
1444  // (icmp sgt X, 4) && (icmp sgt X, 42) --> icmp sgt X, 42
1445  // If this is or-of-compares, take the larger set:
1446  // (icmp sgt X, 4) || (icmp sgt X, 42) --> icmp sgt X, 4
1447  if (Range0.contains(Range1))
1448  return IsAnd ? Cmp1 : Cmp0;
1449  if (Range1.contains(Range0))
1450  return IsAnd ? Cmp0 : Cmp1;
1451 
1452  return nullptr;
1453 }
1454 
1456  bool IsAnd) {
1457  ICmpInst::Predicate P0 = Cmp0->getPredicate(), P1 = Cmp1->getPredicate();
1458  if (!match(Cmp0->getOperand(1), m_Zero()) ||
1459  !match(Cmp1->getOperand(1), m_Zero()) || P0 != P1)
1460  return nullptr;
1461 
1462  if ((IsAnd && P0 != ICmpInst::ICMP_NE) || (!IsAnd && P1 != ICmpInst::ICMP_EQ))
1463  return nullptr;
1464 
1465  // We have either "(X == 0 || Y == 0)" or "(X != 0 && Y != 0)".
1466  Value *X = Cmp0->getOperand(0);
1467  Value *Y = Cmp1->getOperand(0);
1468 
1469  // If one of the compares is a masked version of a (not) null check, then
1470  // that compare implies the other, so we eliminate the other. Optionally, look
1471  // through a pointer-to-int cast to match a null check of a pointer type.
1472 
1473  // (X == 0) || (([ptrtoint] X & ?) == 0) --> ([ptrtoint] X & ?) == 0
1474  // (X == 0) || ((? & [ptrtoint] X) == 0) --> (? & [ptrtoint] X) == 0
1475  // (X != 0) && (([ptrtoint] X & ?) != 0) --> ([ptrtoint] X & ?) != 0
1476  // (X != 0) && ((? & [ptrtoint] X) != 0) --> (? & [ptrtoint] X) != 0
1477  if (match(Y, m_c_And(m_Specific(X), m_Value())) ||
1479  return Cmp1;
1480 
1481  // (([ptrtoint] Y & ?) == 0) || (Y == 0) --> ([ptrtoint] Y & ?) == 0
1482  // ((? & [ptrtoint] Y) == 0) || (Y == 0) --> (? & [ptrtoint] Y) == 0
1483  // (([ptrtoint] Y & ?) != 0) && (Y != 0) --> ([ptrtoint] Y & ?) != 0
1484  // ((? & [ptrtoint] Y) != 0) && (Y != 0) --> (? & [ptrtoint] Y) != 0
1485  if (match(X, m_c_And(m_Specific(Y), m_Value())) ||
1487  return Cmp0;
1488 
1489  return nullptr;
1490 }
1491 
1493  // (icmp (add V, C0), C1) & (icmp V, C0)
1494  ICmpInst::Predicate Pred0, Pred1;
1495  const APInt *C0, *C1;
1496  Value *V;
1497  if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
1498  return nullptr;
1499 
1500  if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
1501  return nullptr;
1502 
1503  auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1504  if (AddInst->getOperand(1) != Op1->getOperand(1))
1505  return nullptr;
1506 
1507  Type *ITy = Op0->getType();
1508  bool isNSW = AddInst->hasNoSignedWrap();
1509  bool isNUW = AddInst->hasNoUnsignedWrap();
1510 
1511  const APInt Delta = *C1 - *C0;
1512  if (C0->isStrictlyPositive()) {
1513  if (Delta == 2) {
1514  if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
1515  return getFalse(ITy);
1516  if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1517  return getFalse(ITy);
1518  }
1519  if (Delta == 1) {
1520  if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
1521  return getFalse(ITy);
1522  if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1523  return getFalse(ITy);
1524  }
1525  }
1526  if (C0->getBoolValue() && isNUW) {
1527  if (Delta == 2)
1528  if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
1529  return getFalse(ITy);
1530  if (Delta == 1)
1531  if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
1532  return getFalse(ITy);
1533  }
1534 
1535  return nullptr;
1536 }
1537 
1539  if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/true))
1540  return X;
1541  if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/true))
1542  return X;
1543 
1544  if (Value *X = simplifyAndOfICmpsWithSameOperands(Op0, Op1))
1545  return X;
1546  if (Value *X = simplifyAndOfICmpsWithSameOperands(Op1, Op0))
1547  return X;
1548 
1549  if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, true))
1550  return X;
1551 
1552  if (Value *X = simplifyAndOrOfICmpsWithZero(Op0, Op1, true))
1553  return X;
1554 
1555  if (Value *X = simplifyAndOfICmpsWithAdd(Op0, Op1))
1556  return X;
1557  if (Value *X = simplifyAndOfICmpsWithAdd(Op1, Op0))
1558  return X;
1559 
1560  return nullptr;
1561 }
1562 
1564  // (icmp (add V, C0), C1) | (icmp V, C0)
1565  ICmpInst::Predicate Pred0, Pred1;
1566  const APInt *C0, *C1;
1567  Value *V;
1568  if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
1569  return nullptr;
1570 
1571  if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
1572  return nullptr;
1573 
1574  auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1575  if (AddInst->getOperand(1) != Op1->getOperand(1))
1576  return nullptr;
1577 
1578  Type *ITy = Op0->getType();
1579  bool isNSW = AddInst->hasNoSignedWrap();
1580  bool isNUW = AddInst->hasNoUnsignedWrap();
1581 
1582  const APInt Delta = *C1 - *C0;
1583  if (C0->isStrictlyPositive()) {
1584  if (Delta == 2) {
1585  if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE)
1586  return getTrue(ITy);
1587  if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1588  return getTrue(ITy);
1589  }
1590  if (Delta == 1) {
1591  if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE)
1592  return getTrue(ITy);
1593  if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1594  return getTrue(ITy);
1595  }
1596  }
1597  if (C0->getBoolValue() && isNUW) {
1598  if (Delta == 2)
1599  if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE)
1600  return getTrue(ITy);
1601  if (Delta == 1)
1602  if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE)
1603  return getTrue(ITy);
1604  }
1605 
1606  return nullptr;
1607 }
1608 
1610  if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/false))
1611  return X;
1612  if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/false))
1613  return X;
1614 
1615  if (Value *X = simplifyOrOfICmpsWithSameOperands(Op0, Op1))
1616  return X;
1617  if (Value *X = simplifyOrOfICmpsWithSameOperands(Op1, Op0))
1618  return X;
1619 
1620  if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, false))
1621  return X;
1622 
1623  if (Value *X = simplifyAndOrOfICmpsWithZero(Op0, Op1, false))
1624  return X;
1625 
1626  if (Value *X = simplifyOrOfICmpsWithAdd(Op0, Op1))
1627  return X;
1628  if (Value *X = simplifyOrOfICmpsWithAdd(Op1, Op0))
1629  return X;
1630 
1631  return nullptr;
1632 }
1633 
1634 static Value *simplifyAndOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS, bool IsAnd) {
1635  Value *LHS0 = LHS->getOperand(0), *LHS1 = LHS->getOperand(1);
1636  Value *RHS0 = RHS->getOperand(0), *RHS1 = RHS->getOperand(1);
1637  if (LHS0->getType() != RHS0->getType())
1638  return nullptr;
1639 
1640  FCmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
1641  if ((PredL == FCmpInst::FCMP_ORD && PredR == FCmpInst::FCMP_ORD && IsAnd) ||
1642  (PredL == FCmpInst::FCMP_UNO && PredR == FCmpInst::FCMP_UNO && !IsAnd)) {
1643  // (fcmp ord NNAN, X) & (fcmp ord X, Y) --> fcmp ord X, Y
1644  // (fcmp ord NNAN, X) & (fcmp ord Y, X) --> fcmp ord Y, X
1645  // (fcmp ord X, NNAN) & (fcmp ord X, Y) --> fcmp ord X, Y
1646  // (fcmp ord X, NNAN) & (fcmp ord Y, X) --> fcmp ord Y, X
1647  // (fcmp uno NNAN, X) | (fcmp uno X, Y) --> fcmp uno X, Y
1648  // (fcmp uno NNAN, X) | (fcmp uno Y, X) --> fcmp uno Y, X
1649  // (fcmp uno X, NNAN) | (fcmp uno X, Y) --> fcmp uno X, Y
1650  // (fcmp uno X, NNAN) | (fcmp uno Y, X) --> fcmp uno Y, X
1651  if ((isKnownNeverNaN(LHS0) && (LHS1 == RHS0 || LHS1 == RHS1)) ||
1652  (isKnownNeverNaN(LHS1) && (LHS0 == RHS0 || LHS0 == RHS1)))
1653  return RHS;
1654 
1655  // (fcmp ord X, Y) & (fcmp ord NNAN, X) --> fcmp ord X, Y
1656  // (fcmp ord Y, X) & (fcmp ord NNAN, X) --> fcmp ord Y, X
1657  // (fcmp ord X, Y) & (fcmp ord X, NNAN) --> fcmp ord X, Y
1658  // (fcmp ord Y, X) & (fcmp ord X, NNAN) --> fcmp ord Y, X
1659  // (fcmp uno X, Y) | (fcmp uno NNAN, X) --> fcmp uno X, Y
1660  // (fcmp uno Y, X) | (fcmp uno NNAN, X) --> fcmp uno Y, X
1661  // (fcmp uno X, Y) | (fcmp uno X, NNAN) --> fcmp uno X, Y
1662  // (fcmp uno Y, X) | (fcmp uno X, NNAN) --> fcmp uno Y, X
1663  if ((isKnownNeverNaN(RHS0) && (RHS1 == LHS0 || RHS1 == LHS1)) ||
1664  (isKnownNeverNaN(RHS1) && (RHS0 == LHS0 || RHS0 == LHS1)))
1665  return LHS;
1666  }
1667 
1668  return nullptr;
1669 }
1670 
1671 static Value *simplifyAndOrOfCmps(Value *Op0, Value *Op1, bool IsAnd) {
1672  // Look through casts of the 'and' operands to find compares.
1673  auto *Cast0 = dyn_cast<CastInst>(Op0);
1674  auto *Cast1 = dyn_cast<CastInst>(Op1);
1675  if (Cast0 && Cast1 && Cast0->getOpcode() == Cast1->getOpcode() &&
1676  Cast0->getSrcTy() == Cast1->getSrcTy()) {
1677  Op0 = Cast0->getOperand(0);
1678  Op1 = Cast1->getOperand(0);
1679  }
1680 
1681  Value *V = nullptr;
1682  auto *ICmp0 = dyn_cast<ICmpInst>(Op0);
1683  auto *ICmp1 = dyn_cast<ICmpInst>(Op1);
1684  if (ICmp0 && ICmp1)
1685  V = IsAnd ? simplifyAndOfICmps(ICmp0, ICmp1) :
1686  simplifyOrOfICmps(ICmp0, ICmp1);
1687 
1688  auto *FCmp0 = dyn_cast<FCmpInst>(Op0);
1689  auto *FCmp1 = dyn_cast<FCmpInst>(Op1);
1690  if (FCmp0 && FCmp1)
1691  V = simplifyAndOrOfFCmps(FCmp0, FCmp1, IsAnd);
1692 
1693  if (!V)
1694  return nullptr;
1695  if (!Cast0)
1696  return V;
1697 
1698  // If we looked through casts, we can only handle a constant simplification
1699  // because we are not allowed to create a cast instruction here.
1700  if (auto *C = dyn_cast<Constant>(V))
1701  return ConstantExpr::getCast(Cast0->getOpcode(), C, Cast0->getType());
1702 
1703  return nullptr;
1704 }
1705 
1706 /// Given operands for an And, see if we can fold the result.
1707 /// If not, this returns null.
1708 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1709  unsigned MaxRecurse) {
1710  if (Constant *C = foldOrCommuteConstant(Instruction::And, Op0, Op1, Q))
1711  return C;
1712 
1713  // X & undef -> 0
1714  if (match(Op1, m_Undef()))
1715  return Constant::getNullValue(Op0->getType());
1716 
1717  // X & X = X
1718  if (Op0 == Op1)
1719  return Op0;
1720 
1721  // X & 0 = 0
1722  if (match(Op1, m_Zero()))
1723  return Constant::getNullValue(Op0->getType());
1724 
1725  // X & -1 = X
1726  if (match(Op1, m_AllOnes()))
1727  return Op0;
1728 
1729  // A & ~A = ~A & A = 0
1730  if (match(Op0, m_Not(m_Specific(Op1))) ||
1731  match(Op1, m_Not(m_Specific(Op0))))
1732  return Constant::getNullValue(Op0->getType());
1733 
1734  // (A | ?) & A = A
1735  if (match(Op0, m_c_Or(m_Specific(Op1), m_Value())))
1736  return Op1;
1737 
1738  // A & (A | ?) = A
1739  if (match(Op1, m_c_Or(m_Specific(Op0), m_Value())))
1740  return Op0;
1741 
1742  // A mask that only clears known zeros of a shifted value is a no-op.
1743  Value *X;
1744  const APInt *Mask;
1745  const APInt *ShAmt;
1746  if (match(Op1, m_APInt(Mask))) {
1747  // If all bits in the inverted and shifted mask are clear:
1748  // and (shl X, ShAmt), Mask --> shl X, ShAmt
1749  if (match(Op0, m_Shl(m_Value(X), m_APInt(ShAmt))) &&
1750  (~(*Mask)).lshr(*ShAmt).isNullValue())
1751  return Op0;
1752 
1753  // If all bits in the inverted and shifted mask are clear:
1754  // and (lshr X, ShAmt), Mask --> lshr X, ShAmt
1755  if (match(Op0, m_LShr(m_Value(X), m_APInt(ShAmt))) &&
1756  (~(*Mask)).shl(*ShAmt).isNullValue())
1757  return Op0;
1758  }
1759 
1760  // A & (-A) = A if A is a power of two or zero.
1761  if (match(Op0, m_Neg(m_Specific(Op1))) ||
1762  match(Op1, m_Neg(m_Specific(Op0)))) {
1763  if (isKnownToBeAPowerOfTwo(Op0, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1764  Q.DT))
1765  return Op0;
1766  if (isKnownToBeAPowerOfTwo(Op1, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1767  Q.DT))
1768  return Op1;
1769  }
1770 
1771  if (Value *V = simplifyAndOrOfCmps(Op0, Op1, true))
1772  return V;
1773 
1774  // Try some generic simplifications for associative operations.
1775  if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1776  MaxRecurse))
1777  return V;
1778 
1779  // And distributes over Or. Try some generic simplifications based on this.
1780  if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1781  Q, MaxRecurse))
1782  return V;
1783 
1784  // And distributes over Xor. Try some generic simplifications based on this.
1785  if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1786  Q, MaxRecurse))
1787  return V;
1788 
1789  // If the operation is with the result of a select instruction, check whether
1790  // operating on either branch of the select always yields the same value.
1791  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1792  if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1793  MaxRecurse))
1794  return V;
1795 
1796  // If the operation is with the result of a phi instruction, check whether
1797  // operating on all incoming values of the phi always yields the same value.
1798  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1799  if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1800  MaxRecurse))
1801  return V;
1802 
1803  return nullptr;
1804 }
1805 
1808 }
1809 
1810 /// Given operands for an Or, see if we can fold the result.
1811 /// If not, this returns null.
1812 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1813  unsigned MaxRecurse) {
1814  if (Constant *C = foldOrCommuteConstant(Instruction::Or, Op0, Op1, Q))
1815  return C;
1816 
1817  // X | undef -> -1
1818  // X | -1 = -1
1819  // Do not return Op1 because it may contain undef elements if it's a vector.
1820  if (match(Op1, m_Undef()) || match(Op1, m_AllOnes()))
1821  return Constant::getAllOnesValue(Op0->getType());
1822 
1823  // X | X = X
1824  // X | 0 = X
1825  if (Op0 == Op1 || match(Op1, m_Zero()))
1826  return Op0;
1827 
1828  // A | ~A = ~A | A = -1
1829  if (match(Op0, m_Not(m_Specific(Op1))) ||
1830  match(Op1, m_Not(m_Specific(Op0))))
1831  return Constant::getAllOnesValue(Op0->getType());
1832 
1833  // (A & ?) | A = A
1834  if (match(Op0, m_c_And(m_Specific(Op1), m_Value())))
1835  return Op1;
1836 
1837  // A | (A & ?) = A
1838  if (match(Op1, m_c_And(m_Specific(Op0), m_Value())))
1839  return Op0;
1840 
1841  // ~(A & ?) | A = -1
1842  if (match(Op0, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
1843  return Constant::getAllOnesValue(Op1->getType());
1844 
1845  // A | ~(A & ?) = -1
1846  if (match(Op1, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
1847  return Constant::getAllOnesValue(Op0->getType());
1848 
1849  Value *A, *B;
1850  // (A & ~B) | (A ^ B) -> (A ^ B)
1851  // (~B & A) | (A ^ B) -> (A ^ B)
1852  // (A & ~B) | (B ^ A) -> (B ^ A)
1853  // (~B & A) | (B ^ A) -> (B ^ A)
1854  if (match(Op1, m_Xor(m_Value(A), m_Value(B))) &&
1855  (match(Op0, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
1856  match(Op0, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
1857  return Op1;
1858 
1859  // Commute the 'or' operands.
1860  // (A ^ B) | (A & ~B) -> (A ^ B)
1861  // (A ^ B) | (~B & A) -> (A ^ B)
1862  // (B ^ A) | (A & ~B) -> (B ^ A)
1863  // (B ^ A) | (~B & A) -> (B ^ A)
1864  if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
1865  (match(Op1, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
1866  match(Op1, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
1867  return Op0;
1868 
1869  // (A & B) | (~A ^ B) -> (~A ^ B)
1870  // (B & A) | (~A ^ B) -> (~A ^ B)
1871  // (A & B) | (B ^ ~A) -> (B ^ ~A)
1872  // (B & A) | (B ^ ~A) -> (B ^ ~A)
1873  if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1874  (match(Op1, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
1875  match(Op1, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
1876  return Op1;
1877 
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(Op1, m_And(m_Value(A), m_Value(B))) &&
1883  (match(Op0, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
1884  match(Op0, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
1885  return Op0;
1886 
1887  if (Value *V = simplifyAndOrOfCmps(Op0, Op1, false))
1888  return V;
1889 
1890  // Try some generic simplifications for associative operations.
1891  if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1892  MaxRecurse))
1893  return V;
1894 
1895  // Or distributes over And. Try some generic simplifications based on this.
1896  if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1897  MaxRecurse))
1898  return V;
1899 
1900  // If the operation is with the result of a select instruction, check whether
1901  // operating on either branch of the select always yields the same value.
1902  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1903  if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1904  MaxRecurse))
1905  return V;
1906 
1907  // (A & C1)|(B & C2)
1908  const APInt *C1, *C2;
1909  if (match(Op0, m_And(m_Value(A), m_APInt(C1))) &&
1910  match(Op1, m_And(m_Value(B), m_APInt(C2)))) {
1911  if (*C1 == ~*C2) {
1912  // (A & C1)|(B & C2)
1913  // If we have: ((V + N) & C1) | (V & C2)
1914  // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
1915  // replace with V+N.
1916  Value *N;
1917  if (C2->isMask() && // C2 == 0+1+
1918  match(A, m_c_Add(m_Specific(B), m_Value(N)))) {
1919  // Add commutes, try both ways.
1920  if (MaskedValueIsZero(N, *C2, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1921  return A;
1922  }
1923  // Or commutes, try both ways.
1924  if (C1->isMask() &&
1925  match(B, m_c_Add(m_Specific(A), m_Value(N)))) {
1926  // Add commutes, try both ways.
1927  if (MaskedValueIsZero(N, *C1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1928  return B;
1929  }
1930  }
1931  }
1932 
1933  // If the operation is with the result of a phi instruction, check whether
1934  // operating on all incoming values of the phi always yields the same value.
1935  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1936  if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1937  return V;
1938 
1939  return nullptr;
1940 }
1941 
1944 }
1945 
1946 /// Given operands for a Xor, see if we can fold the result.
1947 /// If not, this returns null.
1948 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1949  unsigned MaxRecurse) {
1950  if (Constant *C = foldOrCommuteConstant(Instruction::Xor, Op0, Op1, Q))
1951  return C;
1952 
1953  // A ^ undef -> undef
1954  if (match(Op1, m_Undef()))
1955  return Op1;
1956 
1957  // A ^ 0 = A
1958  if (match(Op1, m_Zero()))
1959  return Op0;
1960 
1961  // A ^ A = 0
1962  if (Op0 == Op1)
1963  return Constant::getNullValue(Op0->getType());
1964 
1965  // A ^ ~A = ~A ^ A = -1
1966  if (match(Op0, m_Not(m_Specific(Op1))) ||
1967  match(Op1, m_Not(m_Specific(Op0))))
1968  return Constant::getAllOnesValue(Op0->getType());
1969 
1970  // Try some generic simplifications for associative operations.
1971  if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1972  MaxRecurse))
1973  return V;
1974 
1975  // Threading Xor over selects and phi nodes is pointless, so don't bother.
1976  // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1977  // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1978  // only if B and C are equal. If B and C are equal then (since we assume
1979  // that operands have already been simplified) "select(cond, B, C)" should
1980  // have been simplified to the common value of B and C already. Analysing
1981  // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1982  // for threading over phi nodes.
1983 
1984  return nullptr;
1985 }
1986 
1989 }
1990 
1991 
1993  return CmpInst::makeCmpResultType(Op->getType());
1994 }
1995 
1996 /// Rummage around inside V looking for something equivalent to the comparison
1997 /// "LHS Pred RHS". Return such a value if found, otherwise return null.
1998 /// Helper function for analyzing max/min idioms.
2000  Value *LHS, Value *RHS) {
2002  if (!SI)
2003  return nullptr;
2004  CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
2005  if (!Cmp)
2006  return nullptr;
2007  Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
2008  if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
2009  return Cmp;
2010  if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
2011  LHS == CmpRHS && RHS == CmpLHS)
2012  return Cmp;
2013  return nullptr;
2014 }
2015 
2016 // A significant optimization not implemented here is assuming that alloca
2017 // addresses are not equal to incoming argument values. They don't *alias*,
2018 // as we say, but that doesn't mean they aren't equal, so we take a
2019 // conservative approach.
2020 //
2021 // This is inspired in part by C++11 5.10p1:
2022 // "Two pointers of the same type compare equal if and only if they are both
2023 // null, both point to the same function, or both represent the same
2024 // address."
2025 //
2026 // This is pretty permissive.
2027 //
2028 // It's also partly due to C11 6.5.9p6:
2029 // "Two pointers compare equal if and only if both are null pointers, both are
2030 // pointers to the same object (including a pointer to an object and a
2031 // subobject at its beginning) or function, both are pointers to one past the
2032 // last element of the same array object, or one is a pointer to one past the
2033 // end of one array object and the other is a pointer to the start of a
2034 // different array object that happens to immediately follow the first array
2035 // object in the address space.)
2036 //
2037 // C11's version is more restrictive, however there's no reason why an argument
2038 // couldn't be a one-past-the-end value for a stack object in the caller and be
2039 // equal to the beginning of a stack object in the callee.
2040 //
2041 // If the C and C++ standards are ever made sufficiently restrictive in this
2042 // area, it may be possible to update LLVM's semantics accordingly and reinstate
2043 // this optimization.
2044 static Constant *
2046  const DominatorTree *DT, CmpInst::Predicate Pred,
2047  AssumptionCache *AC, const Instruction *CxtI,
2048  Value *LHS, Value *RHS) {
2049  // First, skip past any trivial no-ops.
2050  LHS = LHS->stripPointerCasts();
2051  RHS = RHS->stripPointerCasts();
2052 
2053  // A non-null pointer is not equal to a null pointer.
2054  if (llvm::isKnownNonZero(LHS, DL) && isa<ConstantPointerNull>(RHS) &&
2055  (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
2056  return ConstantInt::get(GetCompareTy(LHS),
2057  !CmpInst::isTrueWhenEqual(Pred));
2058 
2059  // We can only fold certain predicates on pointer comparisons.
2060  switch (Pred) {
2061  default:
2062  return nullptr;
2063 
2064  // Equality comaprisons are easy to fold.
2065  case CmpInst::ICMP_EQ:
2066  case CmpInst::ICMP_NE:
2067  break;
2068 
2069  // We can only handle unsigned relational comparisons because 'inbounds' on
2070  // a GEP only protects against unsigned wrapping.
2071  case CmpInst::ICMP_UGT:
2072  case CmpInst::ICMP_UGE:
2073  case CmpInst::ICMP_ULT:
2074  case CmpInst::ICMP_ULE:
2075  // However, we have to switch them to their signed variants to handle
2076  // negative indices from the base pointer.
2077  Pred = ICmpInst::getSignedPredicate(Pred);
2078  break;
2079  }
2080 
2081  // Strip off any constant offsets so that we can reason about them.
2082  // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
2083  // here and compare base addresses like AliasAnalysis does, however there are
2084  // numerous hazards. AliasAnalysis and its utilities rely on special rules
2085  // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
2086  // doesn't need to guarantee pointer inequality when it says NoAlias.
2087  Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
2088  Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
2089 
2090  // If LHS and RHS are related via constant offsets to the same base
2091  // value, we can replace it with an icmp which just compares the offsets.
2092  if (LHS == RHS)
2093  return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
2094 
2095  // Various optimizations for (in)equality comparisons.
2096  if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
2097  // Different non-empty allocations that exist at the same time have
2098  // different addresses (if the program can tell). Global variables always
2099  // exist, so they always exist during the lifetime of each other and all
2100  // allocas. Two different allocas usually have different addresses...
2101  //
2102  // However, if there's an @llvm.stackrestore dynamically in between two
2103  // allocas, they may have the same address. It's tempting to reduce the
2104  // scope of the problem by only looking at *static* allocas here. That would
2105  // cover the majority of allocas while significantly reducing the likelihood
2106  // of having an @llvm.stackrestore pop up in the middle. However, it's not
2107  // actually impossible for an @llvm.stackrestore to pop up in the middle of
2108  // an entry block. Also, if we have a block that's not attached to a
2109  // function, we can't tell if it's "static" under the current definition.
2110  // Theoretically, this problem could be fixed by creating a new kind of
2111  // instruction kind specifically for static allocas. Such a new instruction
2112  // could be required to be at the top of the entry block, thus preventing it
2113  // from being subject to a @llvm.stackrestore. Instcombine could even
2114  // convert regular allocas into these special allocas. It'd be nifty.
2115  // However, until then, this problem remains open.
2116  //
2117  // So, we'll assume that two non-empty allocas have different addresses
2118  // for now.
2119  //
2120  // With all that, if the offsets are within the bounds of their allocations
2121  // (and not one-past-the-end! so we can't use inbounds!), and their
2122  // allocations aren't the same, the pointers are not equal.
2123  //
2124  // Note that it's not necessary to check for LHS being a global variable
2125  // address, due to canonicalization and constant folding.
2126  if (isa<AllocaInst>(LHS) &&
2127  (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
2128  ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
2129  ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
2130  uint64_t LHSSize, RHSSize;
2131  ObjectSizeOpts Opts;
2132  Opts.NullIsUnknownSize =
2133  NullPointerIsDefined(cast<AllocaInst>(LHS)->getFunction());
2134  if (LHSOffsetCI && RHSOffsetCI &&
2135  getObjectSize(LHS, LHSSize, DL, TLI, Opts) &&
2136  getObjectSize(RHS, RHSSize, DL, TLI, Opts)) {
2137  const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
2138  const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
2139  if (!LHSOffsetValue.isNegative() &&
2140  !RHSOffsetValue.isNegative() &&
2141  LHSOffsetValue.ult(LHSSize) &&
2142  RHSOffsetValue.ult(RHSSize)) {
2143  return ConstantInt::get(GetCompareTy(LHS),
2144  !CmpInst::isTrueWhenEqual(Pred));
2145  }
2146  }
2147 
2148  // Repeat the above check but this time without depending on DataLayout
2149  // or being able to compute a precise size.
2150  if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
2151  !cast<PointerType>(RHS->getType())->isEmptyTy() &&
2152  LHSOffset->isNullValue() &&
2153  RHSOffset->isNullValue())
2154  return ConstantInt::get(GetCompareTy(LHS),
2155  !CmpInst::isTrueWhenEqual(Pred));
2156  }
2157 
2158  // Even if an non-inbounds GEP occurs along the path we can still optimize
2159  // equality comparisons concerning the result. We avoid walking the whole
2160  // chain again by starting where the last calls to
2161  // stripAndComputeConstantOffsets left off and accumulate the offsets.
2162  Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
2163  Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
2164  if (LHS == RHS)
2165  return ConstantExpr::getICmp(Pred,
2166  ConstantExpr::getAdd(LHSOffset, LHSNoBound),
2167  ConstantExpr::getAdd(RHSOffset, RHSNoBound));
2168 
2169  // If one side of the equality comparison must come from a noalias call
2170  // (meaning a system memory allocation function), and the other side must
2171  // come from a pointer that cannot overlap with dynamically-allocated
2172  // memory within the lifetime of the current function (allocas, byval
2173  // arguments, globals), then determine the comparison result here.
2174  SmallVector<Value *, 8> LHSUObjs, RHSUObjs;
2175  GetUnderlyingObjects(LHS, LHSUObjs, DL);
2176  GetUnderlyingObjects(RHS, RHSUObjs, DL);
2177 
2178  // Is the set of underlying objects all noalias calls?
2179  auto IsNAC = [](ArrayRef<Value *> Objects) {
2180  return all_of(Objects, isNoAliasCall);
2181  };
2182 
2183  // Is the set of underlying objects all things which must be disjoint from
2184  // noalias calls. For allocas, we consider only static ones (dynamic
2185  // allocas might be transformed into calls to malloc not simultaneously
2186  // live with the compared-to allocation). For globals, we exclude symbols
2187  // that might be resolve lazily to symbols in another dynamically-loaded
2188  // library (and, thus, could be malloc'ed by the implementation).
2189  auto IsAllocDisjoint = [](ArrayRef<Value *> Objects) {
2190  return all_of(Objects, [](Value *V) {
2191  if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
2192  return AI->getParent() && AI->getFunction() && AI->isStaticAlloca();
2193  if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
2194  return (GV->hasLocalLinkage() || GV->hasHiddenVisibility() ||
2195  GV->hasProtectedVisibility() || GV->hasGlobalUnnamedAddr()) &&
2196  !GV->isThreadLocal();
2197  if (const Argument *A = dyn_cast<Argument>(V))
2198  return A->hasByValAttr();
2199  return false;
2200  });
2201  };
2202 
2203  if ((IsNAC(LHSUObjs) && IsAllocDisjoint(RHSUObjs)) ||
2204  (IsNAC(RHSUObjs) && IsAllocDisjoint(LHSUObjs)))
2205  return ConstantInt::get(GetCompareTy(LHS),
2206  !CmpInst::isTrueWhenEqual(Pred));
2207 
2208  // Fold comparisons for non-escaping pointer even if the allocation call
2209  // cannot be elided. We cannot fold malloc comparison to null. Also, the
2210  // dynamic allocation call could be either of the operands.
2211  Value *MI = nullptr;
2212  if (isAllocLikeFn(LHS, TLI) &&
2213  llvm::isKnownNonZero(RHS, DL, 0, nullptr, CxtI, DT))
2214  MI = LHS;
2215  else if (isAllocLikeFn(RHS, TLI) &&
2216  llvm::isKnownNonZero(LHS, DL, 0, nullptr, CxtI, DT))
2217  MI = RHS;
2218  // FIXME: We should also fold the compare when the pointer escapes, but the
2219  // compare dominates the pointer escape
2220  if (MI && !PointerMayBeCaptured(MI, true, true))
2221  return ConstantInt::get(GetCompareTy(LHS),
2223  }
2224 
2225  // Otherwise, fail.
2226  return nullptr;
2227 }
2228 
2229 /// Fold an icmp when its operands have i1 scalar type.
2231  Value *RHS, const SimplifyQuery &Q) {
2232  Type *ITy = GetCompareTy(LHS); // The return type.
2233  Type *OpTy = LHS->getType(); // The operand type.
2234  if (!OpTy->isIntOrIntVectorTy(1))
2235  return nullptr;
2236 
2237  // A boolean compared to true/false can be simplified in 14 out of the 20
2238  // (10 predicates * 2 constants) possible combinations. Cases not handled here
2239  // require a 'not' of the LHS, so those must be transformed in InstCombine.
2240  if (match(RHS, m_Zero())) {
2241  switch (Pred) {
2242  case CmpInst::ICMP_NE: // X != 0 -> X
2243  case CmpInst::ICMP_UGT: // X >u 0 -> X
2244  case CmpInst::ICMP_SLT: // X <s 0 -> X
2245  return LHS;
2246 
2247  case CmpInst::ICMP_ULT: // X <u 0 -> false
2248  case CmpInst::ICMP_SGT: // X >s 0 -> false
2249  return getFalse(ITy);
2250 
2251  case CmpInst::ICMP_UGE: // X >=u 0 -> true
2252  case CmpInst::ICMP_SLE: // X <=s 0 -> true
2253  return getTrue(ITy);
2254 
2255  default: break;
2256  }
2257  } else if (match(RHS, m_One())) {
2258  switch (Pred) {
2259  case CmpInst::ICMP_EQ: // X == 1 -> X
2260  case CmpInst::ICMP_UGE: // X >=u 1 -> X
2261  case CmpInst::ICMP_SLE: // X <=s -1 -> X
2262  return LHS;
2263 
2264  case CmpInst::ICMP_UGT: // X >u 1 -> false
2265  case CmpInst::ICMP_SLT: // X <s -1 -> false
2266  return getFalse(ITy);
2267 
2268  case CmpInst::ICMP_ULE: // X <=u 1 -> true
2269  case CmpInst::ICMP_SGE: // X >=s -1 -> true
2270  return getTrue(ITy);
2271 
2272  default: break;
2273  }
2274  }
2275 
2276  switch (Pred) {
2277  default:
2278  break;
2279  case ICmpInst::ICMP_UGE:
2280  if (isImpliedCondition(RHS, LHS, Q.DL).getValueOr(false))
2281  return getTrue(ITy);
2282  break;
2283  case ICmpInst::ICMP_SGE:
2284  /// For signed comparison, the values for an i1 are 0 and -1
2285  /// respectively. This maps into a truth table of:
2286  /// LHS | RHS | LHS >=s RHS | LHS implies RHS
2287  /// 0 | 0 | 1 (0 >= 0) | 1
2288  /// 0 | 1 | 1 (0 >= -1) | 1
2289  /// 1 | 0 | 0 (-1 >= 0) | 0
2290  /// 1 | 1 | 1 (-1 >= -1) | 1
2291  if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2292  return getTrue(ITy);
2293  break;
2294  case ICmpInst::ICMP_ULE:
2295  if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2296  return getTrue(ITy);
2297  break;
2298  }
2299 
2300  return nullptr;
2301 }
2302 
2303 /// Try hard to fold icmp with zero RHS because this is a common case.
2305  Value *RHS, const SimplifyQuery &Q) {
2306  if (!match(RHS, m_Zero()))
2307  return nullptr;
2308 
2309  Type *ITy = GetCompareTy(LHS); // The return type.
2310  switch (Pred) {
2311  default:
2312  llvm_unreachable("Unknown ICmp predicate!");
2313  case ICmpInst::ICMP_ULT:
2314  return getFalse(ITy);
2315  case ICmpInst::ICMP_UGE:
2316  return getTrue(ITy);
2317  case ICmpInst::ICMP_EQ:
2318  case ICmpInst::ICMP_ULE:
2319  if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2320  return getFalse(ITy);
2321  break;
2322  case ICmpInst::ICMP_NE:
2323  case ICmpInst::ICMP_UGT:
2324  if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2325  return getTrue(ITy);
2326  break;
2327  case ICmpInst::ICMP_SLT: {
2328  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2329  if (LHSKnown.isNegative())
2330  return getTrue(ITy);
2331  if (LHSKnown.isNonNegative())
2332  return getFalse(ITy);
2333  break;
2334  }
2335  case ICmpInst::ICMP_SLE: {
2336  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2337  if (LHSKnown.isNegative())
2338  return getTrue(ITy);
2339  if (LHSKnown.isNonNegative() &&
2340  isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2341  return getFalse(ITy);
2342  break;
2343  }
2344  case ICmpInst::ICMP_SGE: {
2345  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2346  if (LHSKnown.isNegative())
2347  return getFalse(ITy);
2348  if (LHSKnown.isNonNegative())
2349  return getTrue(ITy);
2350  break;
2351  }
2352  case ICmpInst::ICMP_SGT: {
2353  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2354  if (LHSKnown.isNegative())
2355  return getFalse(ITy);
2356  if (LHSKnown.isNonNegative() &&
2357  isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2358  return getTrue(ITy);
2359  break;
2360  }
2361  }
2362 
2363  return nullptr;
2364 }
2365 
2366 /// Many binary operators with a constant operand have an easy-to-compute
2367 /// range of outputs. This can be used to fold a comparison to always true or
2368 /// always false.
2369 static void setLimitsForBinOp(BinaryOperator &BO, APInt &Lower, APInt &Upper) {
2370  unsigned Width = Lower.getBitWidth();
2371  const APInt *C;
2372  switch (BO.getOpcode()) {
2373  case Instruction::Add:
2374  if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
2375  // FIXME: If we have both nuw and nsw, we should reduce the range further.
2376  if (BO.hasNoUnsignedWrap()) {
2377  // 'add nuw x, C' produces [C, UINT_MAX].
2378  Lower = *C;
2379  } else if (BO.hasNoSignedWrap()) {
2380  if (C->isNegative()) {
2381  // 'add nsw x, -C' produces [SINT_MIN, SINT_MAX - C].
2382  Lower = APInt::getSignedMinValue(Width);
2383  Upper = APInt::getSignedMaxValue(Width) + *C + 1;
2384  } else {
2385  // 'add nsw x, +C' produces [SINT_MIN + C, SINT_MAX].
2386  Lower = APInt::getSignedMinValue(Width) + *C;
2387  Upper = APInt::getSignedMaxValue(Width) + 1;
2388  }
2389  }
2390  }
2391  break;
2392 
2393  case Instruction::And:
2394  if (match(BO.getOperand(1), m_APInt(C)))
2395  // 'and x, C' produces [0, C].
2396  Upper = *C + 1;
2397  break;
2398 
2399  case Instruction::Or:
2400  if (match(BO.getOperand(1), m_APInt(C)))
2401  // 'or x, C' produces [C, UINT_MAX].
2402  Lower = *C;
2403  break;
2404 
2405  case Instruction::AShr:
2406  if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
2407  // 'ashr x, C' produces [INT_MIN >> C, INT_MAX >> C].
2408  Lower = APInt::getSignedMinValue(Width).ashr(*C);
2409  Upper = APInt::getSignedMaxValue(Width).ashr(*C) + 1;
2410  } else if (match(BO.getOperand(0), m_APInt(C))) {
2411  unsigned ShiftAmount = Width - 1;
2412  if (!C->isNullValue() && BO.isExact())
2413  ShiftAmount = C->countTrailingZeros();
2414  if (C->isNegative()) {
2415  // 'ashr C, x' produces [C, C >> (Width-1)]
2416  Lower = *C;
2417  Upper = C->ashr(ShiftAmount) + 1;
2418  } else {
2419  // 'ashr C, x' produces [C >> (Width-1), C]
2420  Lower = C->ashr(ShiftAmount);
2421  Upper = *C + 1;
2422  }
2423  }
2424  break;
2425 
2426  case Instruction::LShr:
2427  if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
2428  // 'lshr x, C' produces [0, UINT_MAX >> C].
2429  Upper = APInt::getAllOnesValue(Width).lshr(*C) + 1;
2430  } else if (match(BO.getOperand(0), m_APInt(C))) {
2431  // 'lshr C, x' produces [C >> (Width-1), C].
2432  unsigned ShiftAmount = Width - 1;
2433  if (!C->isNullValue() && BO.isExact())
2434  ShiftAmount = C->countTrailingZeros();
2435  Lower = C->lshr(ShiftAmount);
2436  Upper = *C + 1;
2437  }
2438  break;
2439 
2440  case Instruction::Shl:
2441  if (match(BO.getOperand(0), m_APInt(C))) {
2442  if (BO.hasNoUnsignedWrap()) {
2443  // 'shl nuw C, x' produces [C, C << CLZ(C)]
2444  Lower = *C;
2445  Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
2446  } else if (BO.hasNoSignedWrap()) { // TODO: What if both nuw+nsw?
2447  if (C->isNegative()) {
2448  // 'shl nsw C, x' produces [C << CLO(C)-1, C]
2449  unsigned ShiftAmount = C->countLeadingOnes() - 1;
2450  Lower = C->shl(ShiftAmount);
2451  Upper = *C + 1;
2452  } else {
2453  // 'shl nsw C, x' produces [C, C << CLZ(C)-1]
2454  unsigned ShiftAmount = C->countLeadingZeros() - 1;
2455  Lower = *C;
2456  Upper = C->shl(ShiftAmount) + 1;
2457  }
2458  }
2459  }
2460  break;
2461 
2462  case Instruction::SDiv:
2463  if (match(BO.getOperand(1), m_APInt(C))) {
2464  APInt IntMin = APInt::getSignedMinValue(Width);
2465  APInt IntMax = APInt::getSignedMaxValue(Width);
2466  if (C->isAllOnesValue()) {
2467  // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
2468  // where C != -1 and C != 0 and C != 1
2469  Lower = IntMin + 1;
2470  Upper = IntMax + 1;
2471  } else if (C->countLeadingZeros() < Width - 1) {
2472  // 'sdiv x, C' produces [INT_MIN / C, INT_MAX / C]
2473  // where C != -1 and C != 0 and C != 1
2474  Lower = IntMin.sdiv(*C);
2475  Upper = IntMax.sdiv(*C);
2476  if (Lower.sgt(Upper))
2477  std::swap(Lower, Upper);
2478  Upper = Upper + 1;
2479  assert(Upper != Lower && "Upper part of range has wrapped!");
2480  }
2481  } else if (match(BO.getOperand(0), m_APInt(C))) {
2482  if (C->isMinSignedValue()) {
2483  // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
2484  Lower = *C;
2485  Upper = Lower.lshr(1) + 1;
2486  } else {
2487  // 'sdiv C, x' produces [-|C|, |C|].
2488  Upper = C->abs() + 1;
2489  Lower = (-Upper) + 1;
2490  }
2491  }
2492  break;
2493 
2494  case Instruction::UDiv:
2495  if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
2496  // 'udiv x, C' produces [0, UINT_MAX / C].
2497  Upper = APInt::getMaxValue(Width).udiv(*C) + 1;
2498  } else if (match(BO.getOperand(0), m_APInt(C))) {
2499  // 'udiv C, x' produces [0, C].
2500  Upper = *C + 1;
2501  }
2502  break;
2503 
2504  case Instruction::SRem:
2505  if (match(BO.getOperand(1), m_APInt(C))) {
2506  // 'srem x, C' produces (-|C|, |C|).
2507  Upper = C->abs();
2508  Lower = (-Upper) + 1;
2509  }
2510  break;
2511 
2512  case Instruction::URem:
2513  if (match(BO.getOperand(1), m_APInt(C)))
2514  // 'urem x, C' produces [0, C).
2515  Upper = *C;
2516  break;
2517 
2518  default:
2519  break;
2520  }
2521 }
2522 
2524  Value *RHS) {
2525  Type *ITy = GetCompareTy(RHS); // The return type.
2526 
2527  Value *X;
2528  // Sign-bit checks can be optimized to true/false after unsigned
2529  // floating-point casts:
2530  // icmp slt (bitcast (uitofp X)), 0 --> false
2531  // icmp sgt (bitcast (uitofp X)), -1 --> true
2532  if (match(LHS, m_BitCast(m_UIToFP(m_Value(X))))) {
2533  if (Pred == ICmpInst::ICMP_SLT && match(RHS, m_Zero()))
2534  return ConstantInt::getFalse(ITy);
2535  if (Pred == ICmpInst::ICMP_SGT && match(RHS, m_AllOnes()))
2536  return ConstantInt::getTrue(ITy);
2537  }
2538 
2539  const APInt *C;
2540  if (!match(RHS, m_APInt(C)))
2541  return nullptr;
2542 
2543  // Rule out tautological comparisons (eg., ult 0 or uge 0).
2545  if (RHS_CR.isEmptySet())
2546  return ConstantInt::getFalse(ITy);
2547  if (RHS_CR.isFullSet())
2548  return ConstantInt::getTrue(ITy);
2549 
2550  // Find the range of possible values for binary operators.
2551  unsigned Width = C->getBitWidth();
2552  APInt Lower = APInt(Width, 0);
2553  APInt Upper = APInt(Width, 0);
2554  if (auto *BO = dyn_cast<BinaryOperator>(LHS))
2555  setLimitsForBinOp(*BO, Lower, Upper);
2556 
2557  ConstantRange LHS_CR =
2558  Lower != Upper ? ConstantRange(Lower, Upper) : ConstantRange(Width, true);
2559 
2560  if (auto *I = dyn_cast<Instruction>(LHS))
2561  if (auto *Ranges = I->getMetadata(LLVMContext::MD_range))
2562  LHS_CR = LHS_CR.intersectWith(getConstantRangeFromMetadata(*Ranges));
2563 
2564  if (!LHS_CR.isFullSet()) {
2565  if (RHS_CR.contains(LHS_CR))
2566  return ConstantInt::getTrue(ITy);
2567  if (RHS_CR.inverse().contains(LHS_CR))
2568  return ConstantInt::getFalse(ITy);
2569  }
2570 
2571  return nullptr;
2572 }
2573 
2574 /// TODO: A large part of this logic is duplicated in InstCombine's
2575 /// foldICmpBinOp(). We should be able to share that and avoid the code
2576 /// duplication.
2578  Value *RHS, const SimplifyQuery &Q,
2579  unsigned MaxRecurse) {
2580  Type *ITy = GetCompareTy(LHS); // The return type.
2581 
2582  BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2583  BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2584  if (MaxRecurse && (LBO || RBO)) {
2585  // Analyze the case when either LHS or RHS is an add instruction.
2586  Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
2587  // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2588  bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2589  if (LBO && LBO->getOpcode() == Instruction::Add) {
2590  A = LBO->getOperand(0);
2591  B = LBO->getOperand(1);
2592  NoLHSWrapProblem =
2593  ICmpInst::isEquality(Pred) ||
2594  (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2595  (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2596  }
2597  if (RBO && RBO->getOpcode() == Instruction::Add) {
2598  C = RBO->getOperand(0);
2599  D = RBO->getOperand(1);
2600  NoRHSWrapProblem =
2601  ICmpInst::isEquality(Pred) ||
2602  (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2603  (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2604  }
2605 
2606  // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2607  if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2608  if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2609  Constant::getNullValue(RHS->getType()), Q,
2610  MaxRecurse - 1))
2611  return V;
2612 
2613  // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2614  if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2615  if (Value *V =
2617  C == LHS ? D : C, Q, MaxRecurse - 1))
2618  return V;
2619 
2620  // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2621  if (A && C && (A == C || A == D || B == C || B == D) && NoLHSWrapProblem &&
2622  NoRHSWrapProblem) {
2623  // Determine Y and Z in the form icmp (X+Y), (X+Z).
2624  Value *Y, *Z;
2625  if (A == C) {
2626  // C + B == C + D -> B == D
2627  Y = B;
2628  Z = D;
2629  } else if (A == D) {
2630  // D + B == C + D -> B == C
2631  Y = B;
2632  Z = C;
2633  } else if (B == C) {
2634  // A + C == C + D -> A == D
2635  Y = A;
2636  Z = D;
2637  } else {
2638  assert(B == D);
2639  // A + D == C + D -> A == C
2640  Y = A;
2641  Z = C;
2642  }
2643  if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse - 1))
2644  return V;
2645  }
2646  }
2647 
2648  {
2649  Value *Y = nullptr;
2650  // icmp pred (or X, Y), X
2651  if (LBO && match(LBO, m_c_Or(m_Value(Y), m_Specific(RHS)))) {
2652  if (Pred == ICmpInst::ICMP_ULT)
2653  return getFalse(ITy);
2654  if (Pred == ICmpInst::ICMP_UGE)
2655  return getTrue(ITy);
2656 
2657  if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SGE) {
2658  KnownBits RHSKnown = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2659  KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2660  if (RHSKnown.isNonNegative() && YKnown.isNegative())
2661  return Pred == ICmpInst::ICMP_SLT ? getTrue(ITy) : getFalse(ITy);
2662  if (RHSKnown.isNegative() || YKnown.isNonNegative())
2663  return Pred == ICmpInst::ICMP_SLT ? getFalse(ITy) : getTrue(ITy);
2664  }
2665  }
2666  // icmp pred X, (or X, Y)
2667  if (RBO && match(RBO, m_c_Or(m_Value(Y), m_Specific(LHS)))) {
2668  if (Pred == ICmpInst::ICMP_ULE)
2669  return getTrue(ITy);
2670  if (Pred == ICmpInst::ICMP_UGT)
2671  return getFalse(ITy);
2672 
2673  if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SLE) {
2674  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2675  KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2676  if (LHSKnown.isNonNegative() && YKnown.isNegative())
2677  return Pred == ICmpInst::ICMP_SGT ? getTrue(ITy) : getFalse(ITy);
2678  if (LHSKnown.isNegative() || YKnown.isNonNegative())
2679  return Pred == ICmpInst::ICMP_SGT ? getFalse(ITy) : getTrue(ITy);
2680  }
2681  }
2682  }
2683 
2684  // icmp pred (and X, Y), X
2685  if (LBO && match(LBO, m_c_And(m_Value(), m_Specific(RHS)))) {
2686  if (Pred == ICmpInst::ICMP_UGT)
2687  return getFalse(ITy);
2688  if (Pred == ICmpInst::ICMP_ULE)
2689  return getTrue(ITy);
2690  }
2691  // icmp pred X, (and X, Y)
2692  if (RBO && match(RBO, m_c_And(m_Value(), m_Specific(LHS)))) {
2693  if (Pred == ICmpInst::ICMP_UGE)
2694  return getTrue(ITy);
2695  if (Pred == ICmpInst::ICMP_ULT)
2696  return getFalse(ITy);
2697  }
2698 
2699  // 0 - (zext X) pred C
2700  if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
2701  if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
2702  if (RHSC->getValue().isStrictlyPositive()) {
2703  if (Pred == ICmpInst::ICMP_SLT)
2704  return ConstantInt::getTrue(RHSC->getContext());
2705  if (Pred == ICmpInst::ICMP_SGE)
2706  return ConstantInt::getFalse(RHSC->getContext());
2707  if (Pred == ICmpInst::ICMP_EQ)
2708  return ConstantInt::getFalse(RHSC->getContext());
2709  if (Pred == ICmpInst::ICMP_NE)
2710  return ConstantInt::getTrue(RHSC->getContext());
2711  }
2712  if (RHSC->getValue().isNonNegative()) {
2713  if (Pred == ICmpInst::ICMP_SLE)
2714  return ConstantInt::getTrue(RHSC->getContext());
2715  if (Pred == ICmpInst::ICMP_SGT)
2716  return ConstantInt::getFalse(RHSC->getContext());
2717  }
2718  }
2719  }
2720 
2721  // icmp pred (urem X, Y), Y
2722  if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2723  switch (Pred) {
2724  default:
2725  break;
2726  case ICmpInst::ICMP_SGT:
2727  case ICmpInst::ICMP_SGE: {
2728  KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2729  if (!Known.isNonNegative())
2730  break;
2732  }
2733  case ICmpInst::ICMP_EQ:
2734  case ICmpInst::ICMP_UGT:
2735  case ICmpInst::ICMP_UGE:
2736  return getFalse(ITy);
2737  case ICmpInst::ICMP_SLT:
2738  case ICmpInst::ICMP_SLE: {
2739  KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2740  if (!Known.isNonNegative())
2741  break;
2743  }
2744  case ICmpInst::ICMP_NE:
2745  case ICmpInst::ICMP_ULT:
2746  case ICmpInst::ICMP_ULE:
2747  return getTrue(ITy);
2748  }
2749  }
2750 
2751  // icmp pred X, (urem Y, X)
2752  if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2753  switch (Pred) {
2754  default:
2755  break;
2756  case ICmpInst::ICMP_SGT:
2757  case ICmpInst::ICMP_SGE: {
2758  KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2759  if (!Known.isNonNegative())
2760  break;
2762  }
2763  case ICmpInst::ICMP_NE:
2764  case ICmpInst::ICMP_UGT:
2765  case ICmpInst::ICMP_UGE:
2766  return getTrue(ITy);
2767  case ICmpInst::ICMP_SLT:
2768  case ICmpInst::ICMP_SLE: {
2769  KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2770  if (!Known.isNonNegative())
2771  break;
2773  }
2774  case ICmpInst::ICMP_EQ:
2775  case ICmpInst::ICMP_ULT:
2776  case ICmpInst::ICMP_ULE:
2777  return getFalse(ITy);
2778  }
2779  }
2780 
2781  // x >> y <=u x
2782  // x udiv y <=u x.
2783  if (LBO && (match(LBO, m_LShr(m_Specific(RHS), m_Value())) ||
2784  match(LBO, m_UDiv(m_Specific(RHS), m_Value())))) {
2785  // icmp pred (X op Y), X
2786  if (Pred == ICmpInst::ICMP_UGT)
2787  return getFalse(ITy);
2788  if (Pred == ICmpInst::ICMP_ULE)
2789  return getTrue(ITy);
2790  }
2791 
2792  // x >=u x >> y
2793  // x >=u x udiv y.
2794  if (RBO && (match(RBO, m_LShr(m_Specific(LHS), m_Value())) ||
2795  match(RBO, m_UDiv(m_Specific(LHS), m_Value())))) {
2796  // icmp pred X, (X op Y)
2797  if (Pred == ICmpInst::ICMP_ULT)
2798  return getFalse(ITy);
2799  if (Pred == ICmpInst::ICMP_UGE)
2800  return getTrue(ITy);
2801  }
2802 
2803  // handle:
2804  // CI2 << X == CI
2805  // CI2 << X != CI
2806  //
2807  // where CI2 is a power of 2 and CI isn't
2808  if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
2809  const APInt *CI2Val, *CIVal = &CI->getValue();
2810  if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
2811  CI2Val->isPowerOf2()) {
2812  if (!CIVal->isPowerOf2()) {
2813  // CI2 << X can equal zero in some circumstances,
2814  // this simplification is unsafe if CI is zero.
2815  //
2816  // We know it is safe if:
2817  // - The shift is nsw, we can't shift out the one bit.
2818  // - The shift is nuw, we can't shift out the one bit.
2819  // - CI2 is one
2820  // - CI isn't zero
2821  if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
2822  CI2Val->isOneValue() || !CI->isZero()) {
2823  if (Pred == ICmpInst::ICMP_EQ)
2824  return ConstantInt::getFalse(RHS->getContext());
2825  if (Pred == ICmpInst::ICMP_NE)
2826  return ConstantInt::getTrue(RHS->getContext());
2827  }
2828  }
2829  if (CIVal->isSignMask() && CI2Val->isOneValue()) {
2830  if (Pred == ICmpInst::ICMP_UGT)
2831  return ConstantInt::getFalse(RHS->getContext());
2832  if (Pred == ICmpInst::ICMP_ULE)
2833  return ConstantInt::getTrue(RHS->getContext());
2834  }
2835  }
2836  }
2837 
2838  if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2839  LBO->getOperand(1) == RBO->getOperand(1)) {
2840  switch (LBO->getOpcode()) {
2841  default:
2842  break;
2843  case Instruction::UDiv:
2844  case Instruction::LShr:
2845  if (ICmpInst::isSigned(Pred) || !LBO->isExact() || !RBO->isExact())
2846  break;
2847  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2848  RBO->getOperand(0), Q, MaxRecurse - 1))
2849  return V;
2850  break;
2851  case Instruction::SDiv:
2852  if (!ICmpInst::isEquality(Pred) || !LBO->isExact() || !RBO->isExact())
2853  break;
2854  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2855  RBO->getOperand(0), Q, MaxRecurse - 1))
2856  return V;
2857  break;
2858  case Instruction::AShr:
2859  if (!LBO->isExact() || !RBO->isExact())
2860  break;
2861  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2862  RBO->getOperand(0), Q, MaxRecurse - 1))
2863  return V;
2864  break;
2865  case Instruction::Shl: {
2866  bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2867  bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2868  if (!NUW && !NSW)
2869  break;
2870  if (!NSW && ICmpInst::isSigned(Pred))
2871  break;
2872  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2873  RBO->getOperand(0), Q, MaxRecurse - 1))
2874  return V;
2875  break;
2876  }
2877  }
2878  }
2879  return nullptr;
2880 }
2881 
2882 /// Simplify integer comparisons where at least one operand of the compare
2883 /// matches an integer min/max idiom.
2885  Value *RHS, const SimplifyQuery &Q,
2886  unsigned MaxRecurse) {
2887  Type *ITy = GetCompareTy(LHS); // The return type.
2888  Value *A, *B;
2890  CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2891 
2892  // Signed variants on "max(a,b)>=a -> true".
2893  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2894  if (A != RHS)
2895  std::swap(A, B); // smax(A, B) pred A.
2896  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2897  // We analyze this as smax(A, B) pred A.
2898  P = Pred;
2899  } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2900  (A == LHS || B == LHS)) {
2901  if (A != LHS)
2902  std::swap(A, B); // A pred smax(A, B).
2903  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2904  // We analyze this as smax(A, B) swapped-pred A.
2905  P = CmpInst::getSwappedPredicate(Pred);
2906  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2907  (A == RHS || B == RHS)) {
2908  if (A != RHS)
2909  std::swap(A, B); // smin(A, B) pred A.
2910  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2911  // We analyze this as smax(-A, -B) swapped-pred -A.
2912  // Note that we do not need to actually form -A or -B thanks to EqP.
2913  P = CmpInst::getSwappedPredicate(Pred);
2914  } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2915  (A == LHS || B == LHS)) {
2916  if (A != LHS)
2917  std::swap(A, B); // A pred smin(A, B).
2918  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2919  // We analyze this as smax(-A, -B) pred -A.
2920  // Note that we do not need to actually form -A or -B thanks to EqP.
2921  P = Pred;
2922  }
2923  if (P != CmpInst::BAD_ICMP_PREDICATE) {
2924  // Cases correspond to "max(A, B) p A".
2925  switch (P) {
2926  default:
2927  break;
2928  case CmpInst::ICMP_EQ:
2929  case CmpInst::ICMP_SLE:
2930  // Equivalent to "A EqP B". This may be the same as the condition tested
2931  // in the max/min; if so, we can just return that.
2932  if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2933  return V;
2934  if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2935  return V;
2936  // Otherwise, see if "A EqP B" simplifies.
2937  if (MaxRecurse)
2938  if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
2939  return V;
2940  break;
2941  case CmpInst::ICMP_NE:
2942  case CmpInst::ICMP_SGT: {
2944  // Equivalent to "A InvEqP B". This may be the same as the condition
2945  // tested in the max/min; if so, we can just return that.
2946  if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2947  return V;
2948  if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2949  return V;
2950  // Otherwise, see if "A InvEqP B" simplifies.
2951  if (MaxRecurse)
2952  if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
2953  return V;
2954  break;
2955  }
2956  case CmpInst::ICMP_SGE:
2957  // Always true.
2958  return getTrue(ITy);
2959  case CmpInst::ICMP_SLT:
2960  // Always false.
2961  return getFalse(ITy);
2962  }
2963  }
2964 
2965  // Unsigned variants on "max(a,b)>=a -> true".
2967  if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2968  if (A != RHS)
2969  std::swap(A, B); // umax(A, B) pred A.
2970  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2971  // We analyze this as umax(A, B) pred A.
2972  P = Pred;
2973  } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2974  (A == LHS || B == LHS)) {
2975  if (A != LHS)
2976  std::swap(A, B); // A pred umax(A, B).
2977  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2978  // We analyze this as umax(A, B) swapped-pred A.
2979  P = CmpInst::getSwappedPredicate(Pred);
2980  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2981  (A == RHS || B == RHS)) {
2982  if (A != RHS)
2983  std::swap(A, B); // umin(A, B) pred A.
2984  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2985  // We analyze this as umax(-A, -B) swapped-pred -A.
2986  // Note that we do not need to actually form -A or -B thanks to EqP.
2987  P = CmpInst::getSwappedPredicate(Pred);
2988  } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2989  (A == LHS || B == LHS)) {
2990  if (A != LHS)
2991  std::swap(A, B); // A pred umin(A, B).
2992  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2993  // We analyze this as umax(-A, -B) pred -A.
2994  // Note that we do not need to actually form -A or -B thanks to EqP.
2995  P = Pred;
2996  }
2997  if (P != CmpInst::BAD_ICMP_PREDICATE) {
2998  // Cases correspond to "max(A, B) p A".
2999  switch (P) {
3000  default:
3001  break;
3002  case CmpInst::ICMP_EQ:
3003  case CmpInst::ICMP_ULE:
3004  // Equivalent to "A EqP B". This may be the same as the condition tested
3005  // in the max/min; if so, we can just return that.
3006  if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
3007  return V;
3008  if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
3009  return V;
3010  // Otherwise, see if "A EqP B" simplifies.
3011  if (MaxRecurse)
3012  if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
3013  return V;
3014  break;
3015  case CmpInst::ICMP_NE:
3016  case CmpInst::ICMP_UGT: {
3018  // Equivalent to "A InvEqP B". This may be the same as the condition
3019  // tested in the max/min; if so, we can just return that.
3020  if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
3021  return V;
3022  if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
3023  return V;
3024  // Otherwise, see if "A InvEqP B" simplifies.
3025  if (MaxRecurse)
3026  if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
3027  return V;
3028  break;
3029  }
3030  case CmpInst::ICMP_UGE:
3031  // Always true.
3032  return getTrue(ITy);
3033  case CmpInst::ICMP_ULT:
3034  // Always false.
3035  return getFalse(ITy);
3036  }
3037  }
3038 
3039  // Variants on "max(x,y) >= min(x,z)".
3040  Value *C, *D;
3041  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
3042  match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
3043  (A == C || A == D || B == C || B == D)) {
3044  // max(x, ?) pred min(x, ?).
3045  if (Pred == CmpInst::ICMP_SGE)
3046  // Always true.
3047  return getTrue(ITy);
3048  if (Pred == CmpInst::ICMP_SLT)
3049  // Always false.
3050  return getFalse(ITy);
3051  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
3052  match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
3053  (A == C || A == D || B == C || B == D)) {
3054  // min(x, ?) pred max(x, ?).
3055  if (Pred == CmpInst::ICMP_SLE)
3056  // Always true.
3057  return getTrue(ITy);
3058  if (Pred == CmpInst::ICMP_SGT)
3059  // Always false.
3060  return getFalse(ITy);
3061  } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
3062  match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
3063  (A == C || A == D || B == C || B == D)) {
3064  // max(x, ?) pred min(x, ?).
3065  if (Pred == CmpInst::ICMP_UGE)
3066  // Always true.
3067  return getTrue(ITy);
3068  if (Pred == CmpInst::ICMP_ULT)
3069  // Always false.
3070  return getFalse(ITy);
3071  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
3072  match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
3073  (A == C || A == D || B == C || B == D)) {
3074  // min(x, ?) pred max(x, ?).
3075  if (Pred == CmpInst::ICMP_ULE)
3076  // Always true.
3077  return getTrue(ITy);
3078  if (Pred == CmpInst::ICMP_UGT)
3079  // Always false.
3080  return getFalse(ITy);
3081  }
3082 
3083  return nullptr;
3084 }
3085 
3086 /// Given operands for an ICmpInst, see if we can fold the result.
3087 /// If not, this returns null.
3088 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3089  const SimplifyQuery &Q, unsigned MaxRecurse) {
3090  CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3091  assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
3092 
3093  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3094  if (Constant *CRHS = dyn_cast<Constant>(RHS))
3095  return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3096 
3097  // If we have a constant, make sure it is on the RHS.
3098  std::swap(LHS, RHS);
3099  Pred = CmpInst::getSwappedPredicate(Pred);
3100  }
3101 
3102  Type *ITy = GetCompareTy(LHS); // The return type.
3103 
3104  // icmp X, X -> true/false
3105  // icmp X, undef -> true/false because undef could be X.
3106  if (LHS == RHS || isa<UndefValue>(RHS))
3107  return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
3108 
3109  if (Value *V = simplifyICmpOfBools(Pred, LHS, RHS, Q))
3110  return V;
3111 
3112  if (Value *V = simplifyICmpWithZero(Pred, LHS, RHS, Q))
3113  return V;
3114 
3115  if (Value *V = simplifyICmpWithConstant(Pred, LHS, RHS))
3116  return V;
3117 
3118  // If both operands have range metadata, use the metadata
3119  // to simplify the comparison.
3120  if (isa<Instruction>(RHS) && isa<Instruction>(LHS)) {
3121  auto RHS_Instr = cast<Instruction>(RHS);
3122  auto LHS_Instr = cast<Instruction>(LHS);
3123 
3124  if (RHS_Instr->getMetadata(LLVMContext::MD_range) &&
3125  LHS_Instr->getMetadata(LLVMContext::MD_range)) {
3126  auto RHS_CR = getConstantRangeFromMetadata(
3127  *RHS_Instr->getMetadata(LLVMContext::MD_range));
3128  auto LHS_CR = getConstantRangeFromMetadata(
3129  *LHS_Instr->getMetadata(LLVMContext::MD_range));
3130 
3131  auto Satisfied_CR = ConstantRange::makeSatisfyingICmpRegion(Pred, RHS_CR);
3132  if (Satisfied_CR.contains(LHS_CR))
3133  return ConstantInt::getTrue(RHS->getContext());
3134 
3135  auto InversedSatisfied_CR = ConstantRange::makeSatisfyingICmpRegion(
3136  CmpInst::getInversePredicate(Pred), RHS_CR);
3137  if (InversedSatisfied_CR.contains(LHS_CR))
3138  return ConstantInt::getFalse(RHS->getContext());
3139  }
3140  }
3141 
3142  // Compare of cast, for example (zext X) != 0 -> X != 0
3143  if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
3144  Instruction *LI = cast<CastInst>(LHS);
3145  Value *SrcOp = LI->getOperand(0);
3146  Type *SrcTy = SrcOp->getType();
3147  Type *DstTy = LI->getType();
3148 
3149  // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
3150  // if the integer type is the same size as the pointer type.
3151  if (MaxRecurse && isa<PtrToIntInst>(LI) &&
3152  Q.DL.getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
3153  if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
3154  // Transfer the cast to the constant.
3155  if (Value *V = SimplifyICmpInst(Pred, SrcOp,
3156  ConstantExpr::getIntToPtr(RHSC, SrcTy),
3157  Q, MaxRecurse-1))
3158  return V;
3159  } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
3160  if (RI->getOperand(0)->getType() == SrcTy)
3161  // Compare without the cast.
3162  if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
3163  Q, MaxRecurse-1))
3164  return V;
3165  }
3166  }
3167 
3168  if (isa<ZExtInst>(LHS)) {
3169  // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
3170  // same type.
3171  if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
3172  if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3173  // Compare X and Y. Note that signed predicates become unsigned.
3175  SrcOp, RI->getOperand(0), Q,
3176  MaxRecurse-1))
3177  return V;
3178  }
3179  // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
3180  // too. If not, then try to deduce the result of the comparison.
3181  else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3182  // Compute the constant that would happen if we truncated to SrcTy then
3183  // reextended to DstTy.
3184  Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3185  Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
3186 
3187  // If the re-extended constant didn't change then this is effectively
3188  // also a case of comparing two zero-extended values.
3189  if (RExt == CI && MaxRecurse)
3191  SrcOp, Trunc, Q, MaxRecurse-1))
3192  return V;
3193 
3194  // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
3195  // there. Use this to work out the result of the comparison.
3196  if (RExt != CI) {
3197  switch (Pred) {
3198  default: llvm_unreachable("Unknown ICmp predicate!");
3199  // LHS <u RHS.
3200  case ICmpInst::ICMP_EQ:
3201  case ICmpInst::ICMP_UGT:
3202  case ICmpInst::ICMP_UGE:
3203  return ConstantInt::getFalse(CI->getContext());
3204 
3205  case ICmpInst::ICMP_NE:
3206  case ICmpInst::ICMP_ULT:
3207  case ICmpInst::ICMP_ULE:
3208  return ConstantInt::getTrue(CI->getContext());
3209 
3210  // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
3211  // is non-negative then LHS <s RHS.
3212  case ICmpInst::ICMP_SGT:
3213  case ICmpInst::ICMP_SGE:
3214  return CI->getValue().isNegative() ?
3215  ConstantInt::getTrue(CI->getContext()) :
3216  ConstantInt::getFalse(CI->getContext());
3217 
3218  case ICmpInst::ICMP_SLT:
3219  case ICmpInst::ICMP_SLE:
3220  return CI->getValue().isNegative() ?
3221  ConstantInt::getFalse(CI->getContext()) :
3222  ConstantInt::getTrue(CI->getContext());
3223  }
3224  }
3225  }
3226  }
3227 
3228  if (isa<SExtInst>(LHS)) {
3229  // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
3230  // same type.
3231  if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
3232  if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3233  // Compare X and Y. Note that the predicate does not change.
3234  if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
3235  Q, MaxRecurse-1))
3236  return V;
3237  }
3238  // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
3239  // too. If not, then try to deduce the result of the comparison.
3240  else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3241  // Compute the constant that would happen if we truncated to SrcTy then
3242  // reextended to DstTy.
3243  Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3244  Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
3245 
3246  // If the re-extended constant didn't change then this is effectively
3247  // also a case of comparing two sign-extended values.
3248  if (RExt == CI && MaxRecurse)
3249  if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
3250  return V;
3251 
3252  // Otherwise the upper bits of LHS are all equal, while RHS has varying
3253  // bits there. Use this to work out the result of the comparison.
3254  if (RExt != CI) {
3255  switch (Pred) {
3256  default: llvm_unreachable("Unknown ICmp predicate!");
3257  case ICmpInst::ICMP_EQ:
3258  return ConstantInt::getFalse(CI->getContext());
3259  case ICmpInst::ICMP_NE:
3260  return ConstantInt::getTrue(CI->getContext());
3261 
3262  // If RHS is non-negative then LHS <s RHS. If RHS is negative then
3263  // LHS >s RHS.
3264  case ICmpInst::ICMP_SGT:
3265  case ICmpInst::ICMP_SGE:
3266  return CI->getValue().isNegative() ?
3267  ConstantInt::getTrue(CI->getContext()) :
3268  ConstantInt::getFalse(CI->getContext());
3269  case ICmpInst::ICMP_SLT:
3270  case ICmpInst::ICMP_SLE:
3271  return CI->getValue().isNegative() ?
3272  ConstantInt::getFalse(CI->getContext()) :
3273  ConstantInt::getTrue(CI->getContext());
3274 
3275  // If LHS is non-negative then LHS <u RHS. If LHS is negative then
3276  // LHS >u RHS.
3277  case ICmpInst::ICMP_UGT:
3278  case ICmpInst::ICMP_UGE:
3279  // Comparison is true iff the LHS <s 0.
3280  if (MaxRecurse)
3281  if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
3282  Constant::getNullValue(SrcTy),
3283  Q, MaxRecurse-1))
3284  return V;
3285  break;
3286  case ICmpInst::ICMP_ULT:
3287  case ICmpInst::ICMP_ULE:
3288  // Comparison is true iff the LHS >=s 0.
3289  if (MaxRecurse)
3290  if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
3291  Constant::getNullValue(SrcTy),
3292  Q, MaxRecurse-1))
3293  return V;
3294  break;
3295  }
3296  }
3297  }
3298  }
3299  }
3300 
3301  // icmp eq|ne X, Y -> false|true if X != Y
3302  if (ICmpInst::isEquality(Pred) &&
3303  isKnownNonEqual(LHS, RHS, Q.DL, Q.AC, Q.CxtI, Q.DT)) {
3304  return Pred == ICmpInst::ICMP_NE ? getTrue(ITy) : getFalse(ITy);
3305  }
3306 
3307  if (Value *V = simplifyICmpWithBinOp(Pred, LHS, RHS, Q, MaxRecurse))
3308  return V;
3309 
3310  if (Value *V = simplifyICmpWithMinMax(Pred, LHS, RHS, Q, MaxRecurse))
3311  return V;
3312 
3313  // Simplify comparisons of related pointers using a powerful, recursive
3314  // GEP-walk when we have target data available..
3315  if (LHS->getType()->isPointerTy())
3316  if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI, LHS,
3317  RHS))
3318  return C;
3319  if (auto *CLHS = dyn_cast<PtrToIntOperator>(LHS))
3320  if (auto *CRHS = dyn_cast<PtrToIntOperator>(RHS))
3321  if (Q.DL.getTypeSizeInBits(CLHS->getPointerOperandType()) ==
3322  Q.DL.getTypeSizeInBits(CLHS->getType()) &&
3323  Q.DL.getTypeSizeInBits(CRHS->getPointerOperandType()) ==
3324  Q.DL.getTypeSizeInBits(CRHS->getType()))
3325  if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI,
3326  CLHS->getPointerOperand(),
3327  CRHS->getPointerOperand()))
3328  return C;
3329 
3330  if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
3331  if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
3332  if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
3333  GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
3334  (ICmpInst::isEquality(Pred) ||
3335  (GLHS->isInBounds() && GRHS->isInBounds() &&
3336  Pred == ICmpInst::getSignedPredicate(Pred)))) {
3337  // The bases are equal and the indices are constant. Build a constant
3338  // expression GEP with the same indices and a null base pointer to see
3339  // what constant folding can make out of it.
3340  Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
3341  SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
3343  GLHS->getSourceElementType(), Null, IndicesLHS);
3344 
3345  SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
3347  GLHS->getSourceElementType(), Null, IndicesRHS);
3348  return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
3349  }
3350  }
3351  }
3352 
3353  // If the comparison is with the result of a select instruction, check whether
3354  // comparing with either branch of the select always yields the same value.
3355  if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3356  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3357  return V;
3358 
3359  // If the comparison is with the result of a phi instruction, check whether
3360  // doing the compare with each incoming phi value yields a common result.
3361  if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3362  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3363  return V;
3364 
3365  return nullptr;
3366 }
3367 
3368 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3369  const SimplifyQuery &Q) {
3370  return ::SimplifyICmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
3371 }
3372 
3373 /// Given operands for an FCmpInst, see if we can fold the result.
3374 /// If not, this returns null.
3375 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3376  FastMathFlags FMF, const SimplifyQuery &Q,
3377  unsigned MaxRecurse) {
3378  CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3379  assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
3380 
3381  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3382  if (Constant *CRHS = dyn_cast<Constant>(RHS))
3383  return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3384 
3385  // If we have a constant, make sure it is on the RHS.
3386  std::swap(LHS, RHS);
3387  Pred = CmpInst::getSwappedPredicate(Pred);
3388  }
3389 
3390  // Fold trivial predicates.
3391  Type *RetTy = GetCompareTy(LHS);
3392  if (Pred == FCmpInst::FCMP_FALSE)
3393  return getFalse(RetTy);
3394  if (Pred == FCmpInst::FCMP_TRUE)
3395  return getTrue(RetTy);
3396 
3397  // UNO/ORD predicates can be trivially folded if NaNs are ignored.
3398  if (FMF.noNaNs()) {
3399  if (Pred == FCmpInst::FCMP_UNO)
3400  return getFalse(RetTy);
3401  if (Pred == FCmpInst::FCMP_ORD)
3402  return getTrue(RetTy);
3403  }
3404 
3405  // NaN is unordered; NaN is not ordered.
3407  "Comparison must be either ordered or unordered");
3408  if (match(RHS, m_NaN()))
3409  return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred));
3410 
3411  // fcmp pred x, undef and fcmp pred undef, x
3412  // fold to true if unordered, false if ordered
3413  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS)) {
3414  // Choosing NaN for the undef will always make unordered comparison succeed
3415  // and ordered comparison fail.
3416  return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred));
3417  }
3418 
3419  // fcmp x,x -> true/false. Not all compares are foldable.
3420  if (LHS == RHS) {
3421  if (CmpInst::isTrueWhenEqual(Pred))
3422  return getTrue(RetTy);
3423  if (CmpInst::isFalseWhenEqual(Pred))
3424  return getFalse(RetTy);
3425  }
3426 
3427  // Handle fcmp with constant RHS.
3428  const APFloat *C;
3429  if (match(RHS, m_APFloat(C))) {
3430  // Check whether the constant is an infinity.
3431  if (C->isInfinity()) {
3432  if (C->isNegative()) {
3433  switch (Pred) {
3434  case FCmpInst::FCMP_OLT:
3435  // No value is ordered and less than negative infinity.
3436  return getFalse(RetTy);
3437  case FCmpInst::FCMP_UGE:
3438  // All values are unordered with or at least negative infinity.
3439  return getTrue(RetTy);
3440  default:
3441  break;
3442  }
3443  } else {
3444  switch (Pred) {
3445  case FCmpInst::FCMP_OGT:
3446  // No value is ordered and greater than infinity.
3447  return getFalse(RetTy);
3448  case FCmpInst::FCMP_ULE:
3449  // All values are unordered with and at most infinity.
3450  return getTrue(RetTy);
3451  default:
3452  break;
3453  }
3454  }
3455  }
3456  if (C->isZero()) {
3457  switch (Pred) {
3458  case FCmpInst::FCMP_UGE:
3459  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3460  return getTrue(RetTy);
3461  break;
3462  case FCmpInst::FCMP_OLT:
3463  // X < 0
3464  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3465  return getFalse(RetTy);
3466  break;
3467  default:
3468  break;
3469  }
3470  } else if (C->isNegative()) {
3471  assert(!C->isNaN() && "Unexpected NaN constant!");
3472  // TODO: We can catch more cases by using a range check rather than
3473  // relying on CannotBeOrderedLessThanZero.
3474  switch (Pred) {
3475  case FCmpInst::FCMP_UGE:
3476  case FCmpInst::FCMP_UGT:
3477  case FCmpInst::FCMP_UNE:
3478  // (X >= 0) implies (X > C) when (C < 0)
3479  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3480  return getTrue(RetTy);
3481  break;
3482  case FCmpInst::FCMP_OEQ:
3483  case FCmpInst::FCMP_OLE:
3484  case FCmpInst::FCMP_OLT:
3485  // (X >= 0) implies !(X < C) when (C < 0)
3486  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3487  return getFalse(RetTy);
3488  break;
3489  default:
3490  break;
3491  }
3492  }
3493  }
3494 
3495  // If the comparison is with the result of a select instruction, check whether
3496  // comparing with either branch of the select always yields the same value.
3497  if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3498  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3499  return V;
3500 
3501  // If the comparison is with the result of a phi instruction, check whether
3502  // doing the compare with each incoming phi value yields a common result.
3503  if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3504  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3505  return V;
3506 
3507  return nullptr;
3508 }
3509 
3510 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3511  FastMathFlags FMF, const SimplifyQuery &Q) {
3512  return ::SimplifyFCmpInst(Predicate, LHS, RHS, FMF, Q, RecursionLimit);
3513 }
3514 
3515 /// See if V simplifies when its operand Op is replaced with RepOp.
3516 static const Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
3517  const SimplifyQuery &Q,
3518  unsigned MaxRecurse) {
3519  // Trivial replacement.
3520  if (V == Op)
3521  return RepOp;
3522 
3523  // We cannot replace a constant, and shouldn't even try.
3524  if (isa<Constant>(Op))
3525  return nullptr;
3526 
3527  auto *I = dyn_cast<Instruction>(V);
3528  if (!I)
3529  return nullptr;
3530 
3531  // If this is a binary operator, try to simplify it with the replaced op.
3532  if (auto *B = dyn_cast<BinaryOperator>(I)) {
3533  // Consider:
3534  // %cmp = icmp eq i32 %x, 2147483647
3535  // %add = add nsw i32 %x, 1
3536  // %sel = select i1 %cmp, i32 -2147483648, i32 %add
3537  //
3538  // We can't replace %sel with %add unless we strip away the flags.
3539  if (isa<OverflowingBinaryOperator>(B))
3540  if (B->hasNoSignedWrap() || B->hasNoUnsignedWrap())
3541  return nullptr;
3542  if (isa<PossiblyExactOperator>(B))
3543  if (B->isExact())
3544  return nullptr;
3545 
3546  if (MaxRecurse) {
3547  if (B->getOperand(0) == Op)
3548  return SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), Q,
3549  MaxRecurse - 1);
3550  if (B->getOperand(1) == Op)
3551  return SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, Q,
3552  MaxRecurse - 1);
3553  }
3554  }
3555 
3556  // Same for CmpInsts.
3557  if (CmpInst *C = dyn_cast<CmpInst>(I)) {
3558  if (MaxRecurse) {
3559  if (C->getOperand(0) == Op)
3560  return SimplifyCmpInst(C->getPredicate(), RepOp, C->getOperand(1), Q,
3561  MaxRecurse - 1);
3562  if (C->getOperand(1) == Op)
3563  return SimplifyCmpInst(C->getPredicate(), C->getOperand(0), RepOp, Q,
3564  MaxRecurse - 1);
3565  }
3566  }
3567 
3568  // Same for GEPs.
3569  if (auto *GEP = dyn_cast<GetElementPtrInst>(I)) {
3570  if (MaxRecurse) {
3571  SmallVector<Value *, 8> NewOps(GEP->getNumOperands());
3572  transform(GEP->operands(), NewOps.begin(),
3573  [&](Value *V) { return V == Op ? RepOp : V; });
3574  return SimplifyGEPInst(GEP->getSourceElementType(), NewOps, Q,
3575  MaxRecurse - 1);
3576  }
3577  }
3578 
3579  // TODO: We could hand off more cases to instsimplify here.
3580 
3581  // If all operands are constant after substituting Op for RepOp then we can
3582  // constant fold the instruction.
3583  if (Constant *CRepOp = dyn_cast<Constant>(RepOp)) {
3584  // Build a list of all constant operands.
3585  SmallVector<Constant *, 8> ConstOps;
3586  for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
3587  if (I->getOperand(i) == Op)
3588  ConstOps.push_back(CRepOp);
3589  else if (Constant *COp = dyn_cast<Constant>(I->getOperand(i)))
3590  ConstOps.push_back(COp);
3591  else
3592  break;
3593  }
3594 
3595  // All operands were constants, fold it.
3596  if (ConstOps.size() == I->getNumOperands()) {
3597  if (CmpInst *C = dyn_cast<CmpInst>(I))
3598  return ConstantFoldCompareInstOperands(C->getPredicate(), ConstOps[0],
3599  ConstOps[1], Q.DL, Q.TLI);
3600 
3601  if (LoadInst *LI = dyn_cast<LoadInst>(I))
3602  if (!LI->isVolatile())
3603  return ConstantFoldLoadFromConstPtr(ConstOps[0], LI->getType(), Q.DL);
3604 
3605  return ConstantFoldInstOperands(I, ConstOps, Q.DL, Q.TLI);
3606  }
3607  }
3608 
3609  return nullptr;
3610 }
3611 
3612 /// Try to simplify a select instruction when its condition operand is an
3613 /// integer comparison where one operand of the compare is a constant.
3614 static Value *simplifySelectBitTest(Value *TrueVal, Value *FalseVal, Value *X,
3615  const APInt *Y, bool TrueWhenUnset) {
3616  const APInt *C;
3617 
3618  // (X & Y) == 0 ? X & ~Y : X --> X
3619  // (X & Y) != 0 ? X & ~Y : X --> X & ~Y
3620  if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) &&
3621  *Y == ~*C)
3622  return TrueWhenUnset ? FalseVal : TrueVal;
3623 
3624  // (X & Y) == 0 ? X : X & ~Y --> X & ~Y
3625  // (X & Y) != 0 ? X : X & ~Y --> X
3626  if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) &&
3627  *Y == ~*C)
3628  return TrueWhenUnset ? FalseVal : TrueVal;
3629 
3630  if (Y->isPowerOf2()) {
3631  // (X & Y) == 0 ? X | Y : X --> X | Y
3632  // (X & Y) != 0 ? X | Y : X --> X
3633  if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) &&
3634  *Y == *C)
3635  return TrueWhenUnset ? TrueVal : FalseVal;
3636 
3637  // (X & Y) == 0 ? X : X | Y --> X
3638  // (X & Y) != 0 ? X : X | Y --> X | Y
3639  if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) &&
3640  *Y == *C)
3641  return TrueWhenUnset ? TrueVal : FalseVal;
3642  }
3643 
3644  return nullptr;
3645 }
3646 
3647 /// An alternative way to test if a bit is set or not uses sgt/slt instead of
3648 /// eq/ne.
3650  ICmpInst::Predicate Pred,
3651  Value *TrueVal, Value *FalseVal) {
3652  Value *X;
3653  APInt Mask;
3654  if (!decomposeBitTestICmp(CmpLHS, CmpRHS, Pred, X, Mask))
3655  return nullptr;
3656 
3657  return simplifySelectBitTest(TrueVal, FalseVal, X, &Mask,
3658  Pred == ICmpInst::ICMP_EQ);
3659 }
3660 
3661 /// Try to simplify a select instruction when its condition operand is an
3662 /// integer comparison.
3663 static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
3664  Value *FalseVal, const SimplifyQuery &Q,
3665  unsigned MaxRecurse) {
3666  ICmpInst::Predicate Pred;
3667  Value *CmpLHS, *CmpRHS;
3668  if (!match(CondVal, m_ICmp(Pred, m_Value(CmpLHS), m_Value(CmpRHS))))
3669  return nullptr;
3670 
3671  if (ICmpInst::isEquality(Pred) && match(CmpRHS, m_Zero())) {
3672  Value *X;
3673  const APInt *Y;
3674  if (match(CmpLHS, m_And(m_Value(X), m_APInt(Y))))
3675  if (Value *V = simplifySelectBitTest(TrueVal, FalseVal, X, Y,
3676  Pred == ICmpInst::ICMP_EQ))
3677  return V;
3678  }
3679 
3680  // Check for other compares that behave like bit test.
3681  if (Value *V = simplifySelectWithFakeICmpEq(CmpLHS, CmpRHS, Pred,
3682  TrueVal, FalseVal))
3683  return V;
3684 
3685  // If we have an equality comparison, then we know the value in one of the
3686  // arms of the select. See if substituting this value into the arm and
3687  // simplifying the result yields the same value as the other arm.
3688  if (Pred == ICmpInst::ICMP_EQ) {
3689  if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3690  TrueVal ||
3691  SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3692  TrueVal)
3693  return FalseVal;
3694  if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3695  FalseVal ||
3696  SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3697  FalseVal)
3698  return FalseVal;
3699  } else if (Pred == ICmpInst::ICMP_NE) {
3700  if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3701  FalseVal ||
3702  SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3703  FalseVal)
3704  return TrueVal;
3705  if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3706  TrueVal ||
3707  SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3708  TrueVal)
3709  return TrueVal;
3710  }
3711 
3712  return nullptr;
3713 }
3714 
3715 /// Given operands for a SelectInst, see if we can fold the result.
3716 /// If not, this returns null.
3717 static Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3718  const SimplifyQuery &Q, unsigned MaxRecurse) {
3719  if (auto *CondC = dyn_cast<Constant>(Cond)) {
3720  if (auto *TrueC = dyn_cast<Constant>(TrueVal))
3721  if (auto *FalseC = dyn_cast<Constant>(FalseVal))
3722  return ConstantFoldSelectInstruction(CondC, TrueC, FalseC);
3723 
3724  // select undef, X, Y -> X or Y
3725  if (isa<UndefValue>(CondC))
3726  return isa<Constant>(FalseVal) ? FalseVal : TrueVal;
3727 
3728  // TODO: Vector constants with undef elements don't simplify.
3729 
3730  // select true, X, Y -> X
3731  if (CondC->isAllOnesValue())
3732  return TrueVal;
3733  // select false, X, Y -> Y
3734  if (CondC->isNullValue())
3735  return FalseVal;
3736  }
3737 
3738  // select ?, X, X -> X
3739  if (TrueVal == FalseVal)
3740  return TrueVal;
3741 
3742  if (isa<UndefValue>(TrueVal)) // select ?, undef, X -> X
3743  return FalseVal;
3744  if (isa<UndefValue>(FalseVal)) // select ?, X, undef -> X
3745  return TrueVal;
3746 
3747  if (Value *V =
3748  simplifySelectWithICmpCond(Cond, TrueVal, FalseVal, Q, MaxRecurse))
3749  return V;
3750 
3751  return nullptr;
3752 }
3753 
3754 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3755  const SimplifyQuery &Q) {
3756  return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Q, RecursionLimit);
3757 }
3758 
3759 /// Given operands for an GetElementPtrInst, see if we can fold the result.
3760 /// If not, this returns null.
3762  const SimplifyQuery &Q, unsigned) {
3763  // The type of the GEP pointer operand.
3764  unsigned AS =
3765  cast<PointerType>(Ops[0]->getType()->getScalarType())->getAddressSpace();
3766 
3767  // getelementptr P -> P.
3768  if (Ops.size() == 1)
3769  return Ops[0];
3770 
3771  // Compute the (pointer) type returned by the GEP instruction.
3772  Type *LastType = GetElementPtrInst::getIndexedType(SrcTy, Ops.slice(1));
3773  Type *GEPTy = PointerType::get(LastType, AS);
3774  if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
3775  GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3776  else if (VectorType *VT = dyn_cast<VectorType>(Ops[1]->getType()))
3777  GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3778 
3779  if (isa<UndefValue>(Ops[0]))
3780  return UndefValue::get(GEPTy);
3781 
3782  if (Ops.size() == 2) {
3783  // getelementptr P, 0 -> P.
3784  if (match(Ops[1], m_Zero()) && Ops[0]->getType() == GEPTy)
3785  return Ops[0];
3786 
3787  Type *Ty = SrcTy;
3788  if (Ty->isSized()) {
3789  Value *P;
3790  uint64_t C;
3791  uint64_t TyAllocSize = Q.DL.getTypeAllocSize(Ty);
3792  // getelementptr P, N -> P if P points to a type of zero size.
3793  if (TyAllocSize == 0 && Ops[0]->getType() == GEPTy)
3794  return Ops[0];
3795 
3796  // The following transforms are only safe if the ptrtoint cast
3797  // doesn't truncate the pointers.
3798  if (Ops[1]->getType()->getScalarSizeInBits() ==
3799  Q.DL.getIndexSizeInBits(AS)) {
3800  auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
3801  if (match(P, m_Zero()))
3802  return Constant::getNullValue(GEPTy);
3803  Value *Temp;
3804  if (match(P, m_PtrToInt(m_Value(Temp))))
3805  if (Temp->getType() == GEPTy)
3806  return Temp;
3807  return nullptr;
3808  };
3809 
3810  // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
3811  if (TyAllocSize == 1 &&
3812  match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
3813  if (Value *R = PtrToIntOrZero(P))
3814  return R;
3815 
3816  // getelementptr V, (ashr (sub P, V), C) -> Q
3817  // if P points to a type of size 1 << C.
3818  if (match(Ops[1],
3819  m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3820  m_ConstantInt(C))) &&
3821  TyAllocSize == 1ULL << C)
3822  if (Value *R = PtrToIntOrZero(P))
3823  return R;
3824 
3825  // getelementptr V, (sdiv (sub P, V), C) -> Q
3826  // if P points to a type of size C.
3827  if (match(Ops[1],
3828  m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3829  m_SpecificInt(TyAllocSize))))
3830  if (Value *R = PtrToIntOrZero(P))
3831  return R;
3832  }
3833  }
3834  }
3835 
3836  if (Q.DL.getTypeAllocSize(LastType) == 1 &&
3837  all_of(Ops.slice(1).drop_back(1),
3838  [](Value *Idx) { return match(Idx, m_Zero()); })) {
3839  unsigned IdxWidth =
3840  Q.DL.getIndexSizeInBits(Ops[0]->getType()->getPointerAddressSpace());
3841  if (Q.DL.getTypeSizeInBits(Ops.back()->getType()) == IdxWidth) {
3842  APInt BasePtrOffset(IdxWidth, 0);
3843  Value *StrippedBasePtr =
3844  Ops[0]->stripAndAccumulateInBoundsConstantOffsets(Q.DL,
3845  BasePtrOffset);
3846 
3847  // gep (gep V, C), (sub 0, V) -> C
3848  if (match(Ops.back(),
3849  m_Sub(m_Zero(), m_PtrToInt(m_Specific(StrippedBasePtr))))) {
3850  auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset);
3851  return ConstantExpr::getIntToPtr(CI, GEPTy);
3852  }
3853  // gep (gep V, C), (xor V, -1) -> C-1
3854  if (match(Ops.back(),
3855  m_Xor(m_PtrToInt(m_Specific(StrippedBasePtr)), m_AllOnes()))) {
3856  auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset - 1);
3857  return ConstantExpr::getIntToPtr(CI, GEPTy);
3858  }
3859  }
3860  }
3861 
3862  // Check to see if this is constant foldable.
3863  if (!all_of(Ops, [](Value *V) { return isa<Constant>(V); }))
3864  return nullptr;
3865 
3866  auto *CE = ConstantExpr::getGetElementPtr(SrcTy, cast<Constant>(Ops[0]),
3867  Ops.slice(1));
3868  if (auto *CEFolded = ConstantFoldConstant(CE, Q.DL))
3869  return CEFolded;
3870  return CE;
3871 }
3872 
3874  const SimplifyQuery &Q) {
3875  return ::SimplifyGEPInst(SrcTy, Ops, Q, RecursionLimit);
3876 }
3877 
3878 /// Given operands for an InsertValueInst, see if we can fold the result.
3879 /// If not, this returns null.
3881  ArrayRef<unsigned> Idxs, const SimplifyQuery &Q,
3882  unsigned) {
3883  if (Constant *CAgg = dyn_cast<Constant>(Agg))
3884  if (Constant *CVal = dyn_cast<Constant>(Val))
3885  return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
3886 
3887  // insertvalue x, undef, n -> x
3888  if (match(Val, m_Undef()))
3889  return Agg;
3890 
3891  // insertvalue x, (extractvalue y, n), n
3892  if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
3893  if (EV->getAggregateOperand()->getType() == Agg->getType() &&
3894  EV->getIndices() == Idxs) {
3895  // insertvalue undef, (extractvalue y, n), n -> y
3896  if (match(Agg, m_Undef()))
3897  return EV->getAggregateOperand();
3898 
3899  // insertvalue y, (extractvalue y, n), n -> y
3900  if (Agg == EV->getAggregateOperand())
3901  return Agg;
3902  }
3903 
3904  return nullptr;
3905 }
3906 
3908  ArrayRef<unsigned> Idxs,
3909  const SimplifyQuery &Q) {
3911 }
3912 
3914  const SimplifyQuery &Q) {
3915  // Try to constant fold.
3916  auto *VecC = dyn_cast<Constant>(Vec);
3917  auto *ValC = dyn_cast<Constant>(Val);
3918  auto *IdxC = dyn_cast<Constant>(Idx);
3919  if (VecC && ValC && IdxC)
3920  return ConstantFoldInsertElementInstruction(VecC, ValC, IdxC);
3921 
3922  // Fold into undef if index is out of bounds.
3923  if (auto *CI = dyn_cast<ConstantInt>(Idx)) {
3924  uint64_t NumElements = cast<VectorType>(Vec->getType())->getNumElements();
3925  if (CI->uge(NumElements))
3926  return UndefValue::get(Vec->getType());
3927  }
3928 
3929  // If index is undef, it might be out of bounds (see above case)
3930  if (isa<UndefValue>(Idx))
3931  return UndefValue::get(Vec->getType());
3932 
3933  return nullptr;
3934 }
3935 
3936 /// Given operands for an ExtractValueInst, see if we can fold the result.
3937 /// If not, this returns null.
3939  const SimplifyQuery &, unsigned) {
3940  if (auto *CAgg = dyn_cast<Constant>(Agg))
3941  return ConstantFoldExtractValueInstruction(CAgg, Idxs);
3942 
3943  // extractvalue x, (insertvalue y, elt, n), n -> elt
3944  unsigned NumIdxs = Idxs.size();
3945  for (auto *IVI = dyn_cast<InsertValueInst>(Agg); IVI != nullptr;
3946  IVI = dyn_cast<InsertValueInst>(IVI->getAggregateOperand())) {
3947  ArrayRef<unsigned> InsertValueIdxs = IVI->getIndices();
3948  unsigned NumInsertValueIdxs = InsertValueIdxs.size();
3949  unsigned NumCommonIdxs = std::min(NumInsertValueIdxs, NumIdxs);
3950  if (InsertValueIdxs.slice(0, NumCommonIdxs) ==
3951  Idxs.slice(0, NumCommonIdxs)) {
3952  if (NumIdxs == NumInsertValueIdxs)
3953  return IVI->getInsertedValueOperand();
3954  break;
3955  }
3956  }
3957 
3958  return nullptr;
3959 }
3960 
3962  const SimplifyQuery &Q) {
3964 }
3965 
3966 /// Given operands for an ExtractElementInst, see if we can fold the result.
3967 /// If not, this returns null.
3969  unsigned) {
3970  if (auto *CVec = dyn_cast<Constant>(Vec)) {
3971  if (auto *CIdx = dyn_cast<Constant>(Idx))
3972  return ConstantFoldExtractElementInstruction(CVec, CIdx);
3973 
3974  // The index is not relevant if our vector is a splat.
3975  if (auto *Splat = CVec->getSplatValue())
3976  return Splat;
3977 
3978  if (isa<UndefValue>(Vec))
3979  return UndefValue::get(Vec->getType()->getVectorElementType());
3980  }
3981 
3982  // If extracting a specified index from the vector, see if we can recursively
3983  // find a previously computed scalar that was inserted into the vector.
3984  if (auto *IdxC = dyn_cast<ConstantInt>(Idx)) {
3985  if (IdxC->getValue().uge(Vec->getType()->getVectorNumElements()))
3986  // definitely out of bounds, thus undefined result
3987  return UndefValue::get(Vec->getType()->getVectorElementType());
3988  if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue()))
3989  return Elt;
3990  }
3991 
3992  // An undef extract index can be arbitrarily chosen to be an out-of-range
3993  // index value, which would result in the instruction being undef.
3994  if (isa<UndefValue>(Idx))
3995  return UndefValue::get(Vec->getType()->getVectorElementType());
3996 
3997  return nullptr;
3998 }
3999 
4001  const SimplifyQuery &Q) {
4003 }
4004 
4005 /// See if we can fold the given phi. If not, returns null.
4006 static Value *SimplifyPHINode(PHINode *PN, const SimplifyQuery &Q) {
4007  // If all of the PHI's incoming values are the same then replace the PHI node
4008  // with the common value.
4009  Value *CommonValue = nullptr;
4010  bool HasUndefInput = false;
4011  for (Value *Incoming : PN->incoming_values()) {
4012  // If the incoming value is the phi node itself, it can safely be skipped.
4013  if (Incoming == PN) continue;
4014  if (isa<UndefValue>(Incoming)) {
4015  // Remember that we saw an undef value, but otherwise ignore them.
4016  HasUndefInput = true;
4017  continue;
4018  }
4019  if (CommonValue && Incoming != CommonValue)
4020  return nullptr; // Not the same, bail out.
4021  CommonValue = Incoming;
4022  }
4023 
4024  // If CommonValue is null then all of the incoming values were either undef or
4025  // equal to the phi node itself.
4026  if (!CommonValue)
4027  return UndefValue::get(PN->getType());
4028 
4029  // If we have a PHI node like phi(X, undef, X), where X is defined by some
4030  // instruction, we cannot return X as the result of the PHI node unless it
4031  // dominates the PHI block.
4032  if (HasUndefInput)
4033  return valueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
4034 
4035  return CommonValue;
4036 }
4037 
4038 static Value *SimplifyCastInst(unsigned CastOpc, Value *Op,
4039  Type *Ty, const SimplifyQuery &Q, unsigned MaxRecurse) {
4040  if (auto *C = dyn_cast<Constant>(Op))
4041  return ConstantFoldCastOperand(CastOpc, C, Ty, Q.DL);
4042 
4043  if (auto *CI = dyn_cast<CastInst>(Op)) {
4044  auto *Src = CI->getOperand(0);
4045  Type *SrcTy = Src->getType();
4046  Type *MidTy = CI->getType();
4047  Type *DstTy = Ty;
4048  if (Src->getType() == Ty) {
4049  auto FirstOp = static_cast<Instruction::CastOps>(CI->getOpcode());
4050  auto SecondOp = static_cast<Instruction::CastOps>(CastOpc);
4051  Type *SrcIntPtrTy =
4052  SrcTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(SrcTy) : nullptr;
4053  Type *MidIntPtrTy =
4054  MidTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(MidTy) : nullptr;
4055  Type *DstIntPtrTy =
4056  DstTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(DstTy) : nullptr;
4057  if (CastInst::isEliminableCastPair(FirstOp, SecondOp, SrcTy, MidTy, DstTy,
4058  SrcIntPtrTy, MidIntPtrTy,
4059  DstIntPtrTy) == Instruction::BitCast)
4060  return Src;
4061  }
4062  }
4063 
4064  // bitcast x -> x
4065  if (CastOpc == Instruction::BitCast)
4066  if (Op->getType() == Ty)
4067  return Op;
4068 
4069  return nullptr;
4070 }
4071 
4072 Value *llvm::SimplifyCastInst(unsigned CastOpc, Value *Op, Type *Ty,
4073  const SimplifyQuery &Q) {
4074  return ::SimplifyCastInst(CastOpc, Op, Ty, Q, RecursionLimit);
4075 }
4076 
4077 /// For the given destination element of a shuffle, peek through shuffles to
4078 /// match a root vector source operand that contains that element in the same
4079 /// vector lane (ie, the same mask index), so we can eliminate the shuffle(s).
4080 static Value *foldIdentityShuffles(int DestElt, Value *Op0, Value *Op1,
4081  int MaskVal, Value *RootVec,
4082  unsigned MaxRecurse) {
4083  if (!MaxRecurse--)
4084  return nullptr;
4085 
4086  // Bail out if any mask value is undefined. That kind of shuffle may be
4087  // simplified further based on demanded bits or other folds.
4088  if (MaskVal == -1)
4089  return nullptr;
4090 
4091  // The mask value chooses which source operand we need to look at next.
4092  int InVecNumElts = Op0->getType()->getVectorNumElements();
4093  int RootElt = MaskVal;
4094  Value *SourceOp = Op0;
4095  if (MaskVal >= InVecNumElts) {
4096  RootElt = MaskVal - InVecNumElts;
4097  SourceOp = Op1;
4098  }
4099 
4100  // If the source operand is a shuffle itself, look through it to find the
4101  // matching root vector.
4102  if (auto *SourceShuf = dyn_cast<ShuffleVectorInst>(SourceOp)) {
4103  return foldIdentityShuffles(
4104  DestElt, SourceShuf->getOperand(0), SourceShuf->getOperand(1),
4105  SourceShuf->getMaskValue(RootElt), RootVec, MaxRecurse);
4106  }
4107 
4108  // TODO: Look through bitcasts? What if the bitcast changes the vector element
4109  // size?
4110 
4111  // The source operand is not a shuffle. Initialize the root vector value for
4112  // this shuffle if that has not been done yet.
4113  if (!RootVec)
4114  RootVec = SourceOp;
4115 
4116  // Give up as soon as a source operand does not match the existing root value.
4117  if (RootVec != SourceOp)
4118  return nullptr;
4119 
4120  // The element must be coming from the same lane in the source vector
4121  // (although it may have crossed lanes in intermediate shuffles).
4122  if (RootElt != DestElt)
4123  return nullptr;
4124 
4125  return RootVec;
4126 }
4127 
4129  Type *RetTy, const SimplifyQuery &Q,
4130  unsigned MaxRecurse) {
4131  if (isa<UndefValue>(Mask))
4132  return UndefValue::get(RetTy);
4133 
4134  Type *InVecTy = Op0->getType();
4135  unsigned MaskNumElts = Mask->getType()->getVectorNumElements();
4136  unsigned InVecNumElts = InVecTy->getVectorNumElements();
4137 
4138  SmallVector<int, 32> Indices;
4139  ShuffleVectorInst::getShuffleMask(Mask, Indices);
4140  assert(MaskNumElts == Indices.size() &&
4141  "Size of Indices not same as number of mask elements?");
4142 
4143  // Canonicalization: If mask does not select elements from an input vector,
4144  // replace that input vector with undef.
4145  bool MaskSelects0 = false, MaskSelects1 = false;
4146  for (unsigned i = 0; i != MaskNumElts; ++i) {
4147  if (Indices[i] == -1)
4148  continue;
4149  if ((unsigned)Indices[i] < InVecNumElts)
4150  MaskSelects0 = true;
4151  else
4152  MaskSelects1 = true;
4153  }
4154  if (!MaskSelects0)
4155  Op0 = UndefValue::get(InVecTy);
4156  if (!MaskSelects1)
4157  Op1 = UndefValue::get(InVecTy);
4158 
4159  auto *Op0Const = dyn_cast<Constant>(Op0);
4160  auto *Op1Const = dyn_cast<Constant>(Op1);
4161 
4162  // If all operands are constant, constant fold the shuffle.
4163  if (Op0Const && Op1Const)
4164  return ConstantFoldShuffleVectorInstruction(Op0Const, Op1Const, Mask);
4165 
4166  // Canonicalization: if only one input vector is constant, it shall be the
4167  // second one.
4168  if (Op0Const && !Op1Const) {
4169  std::swap(Op0, Op1);
4170  ShuffleVectorInst::commuteShuffleMask(Indices, InVecNumElts);
4171  }
4172 
4173  // A shuffle of a splat is always the splat itself. Legal if the shuffle's
4174  // value type is same as the input vectors' type.
4175  if (auto *OpShuf = dyn_cast<ShuffleVectorInst>(Op0))
4176  if (isa<UndefValue>(Op1) && RetTy == InVecTy &&
4177  OpShuf->getMask()->getSplatValue())
4178  return Op0;
4179 
4180  // Don't fold a shuffle with undef mask elements. This may get folded in a
4181  // better way using demanded bits or other analysis.
4182  // TODO: Should we allow this?
4183  if (find(Indices, -1) != Indices.end())
4184  return nullptr;
4185 
4186  // Check if every element of this shuffle can be mapped back to the
4187  // corresponding element of a single root vector. If so, we don't need this
4188  // shuffle. This handles simple identity shuffles as well as chains of
4189  // shuffles that may widen/narrow and/or move elements across lanes and back.
4190  Value *RootVec = nullptr;
4191  for (unsigned i = 0; i != MaskNumElts; ++i) {
4192  // Note that recursion is limited for each vector element, so if any element
4193  // exceeds the limit, this will fail to simplify.
4194  RootVec =
4195  foldIdentityShuffles(i, Op0, Op1, Indices[i], RootVec, MaxRecurse);
4196 
4197  // We can't replace a widening/narrowing shuffle with one of its operands.
4198  if (!RootVec || RootVec->getType() != RetTy)
4199  return nullptr;
4200  }
4201  return RootVec;
4202 }
4203 
4204 /// Given operands for a ShuffleVectorInst, fold the result or return null.
4206  Type *RetTy, const SimplifyQuery &Q) {
4207  return ::SimplifyShuffleVectorInst(Op0, Op1, Mask, RetTy, Q, RecursionLimit);
4208 }
4209 
4211  // If the input is a vector with undef elements, just return a default NaN.
4212  if (!In->isNaN())
4213  return ConstantFP::getNaN(In->getType());
4214 
4215  // Propagate the existing NaN constant when possible.
4216  // TODO: Should we quiet a signaling NaN?
4217  return In;
4218 }
4219 
4220 static Constant *simplifyFPBinop(Value *Op0, Value *Op1) {
4221  if (isa<UndefValue>(Op0) || isa<UndefValue>(Op1))
4222  return ConstantFP::getNaN(Op0->getType());
4223 
4224  if (match(Op0, m_NaN()))
4225  return propagateNaN(cast<Constant>(Op0));
4226  if (match(Op1, m_NaN()))
4227  return propagateNaN(cast<Constant>(Op1));
4228 
4229  return nullptr;
4230 }
4231 
4232 /// Given operands for an FAdd, see if we can fold the result. If not, this
4233 /// returns null.
4235  const SimplifyQuery &Q, unsigned MaxRecurse) {
4236  if (Constant *C = foldOrCommuteConstant(Instruction::FAdd, Op0, Op1, Q))
4237  return C;
4238 
4239  if (Constant *C = simplifyFPBinop(Op0, Op1))
4240  return C;
4241 
4242  // fadd X, -0 ==> X
4243  if (match(Op1, m_NegZeroFP()))
4244  return Op0;
4245 
4246  // fadd X, 0 ==> X, when we know X is not -0
4247  if (match(Op1, m_PosZeroFP()) &&
4248  (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
4249  return Op0;
4250 
4251  // With nnan: (+/-0.0 - X) + X --> 0.0 (and commuted variant)
4252  // We don't have to explicitly exclude infinities (ninf): INF + -INF == NaN.
4253  // Negative zeros are allowed because we always end up with positive zero:
4254  // X = -0.0: (-0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
4255  // X = -0.0: ( 0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
4256  // X = 0.0: (-0.0 - ( 0.0)) + ( 0.0) == (-0.0) + ( 0.0) == 0.0
4257  // X = 0.0: ( 0.0 - ( 0.0)) + ( 0.0) == ( 0.0) + ( 0.0) == 0.0
4258  if (FMF.noNaNs() && (match(Op0, m_FSub(m_AnyZeroFP(), m_Specific(Op1))) ||
4259  match(Op1, m_FSub(m_AnyZeroFP(), m_Specific(Op0)))))
4260  return ConstantFP::getNullValue(Op0->getType());
4261 
4262  return nullptr;
4263 }
4264 
4265 /// Given operands for an FSub, see if we can fold the result. If not, this
4266 /// returns null.
4268  const SimplifyQuery &Q, unsigned MaxRecurse) {
4269  if (Constant *C = foldOrCommuteConstant(Instruction::FSub, Op0, Op1, Q))
4270  return C;
4271 
4272  if (Constant *C = simplifyFPBinop(Op0, Op1))
4273  return C;
4274 
4275  // fsub X, +0 ==> X
4276  if (match(Op1, m_PosZeroFP()))
4277  return Op0;
4278 
4279  // fsub X, -0 ==> X, when we know X is not -0
4280  if (match(Op1, m_NegZeroFP()) &&
4281  (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
4282  return Op0;
4283 
4284  // fsub -0.0, (fsub -0.0, X) ==> X
4285  Value *X;
4286  if (match(Op0, m_NegZeroFP()) &&
4287  match(Op1, m_FSub(m_NegZeroFP(), m_Value(X))))
4288  return X;
4289 
4290  // fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored.
4291  if (FMF.noSignedZeros() && match(Op0, m_AnyZeroFP()) &&
4292  match(Op1, m_FSub(m_AnyZeroFP(), m_Value(X))))
4293  return X;
4294 
4295  // fsub nnan x, x ==> 0.0
4296  if (FMF.noNaNs() && Op0 == Op1)
4297  return Constant::getNullValue(Op0->getType());
4298 
4299  return nullptr;
4300 }
4301 
4302 /// Given the operands for an FMul, see if we can fold the result
4304  const SimplifyQuery &Q, unsigned MaxRecurse) {
4305  if (Constant *C = foldOrCommuteConstant(Instruction::FMul, Op0, Op1, Q))
4306  return C;
4307 
4308  if (Constant *C = simplifyFPBinop(Op0, Op1))
4309  return C;
4310 
4311  // fmul X, 1.0 ==> X
4312  if (match(Op1, m_FPOne()))
4313  return Op0;
4314 
4315  // fmul nnan nsz X, 0 ==> 0
4316  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZeroFP()))
4317  return ConstantFP::getNullValue(Op0->getType());
4318 
4319  // sqrt(X) * sqrt(X) --> X, if we can:
4320  // 1. Remove the intermediate rounding (reassociate).
4321  // 2. Ignore non-zero negative numbers because sqrt would produce NAN.
4322  // 3. Ignore -0.0 because sqrt(-0.0) == -0.0, but -0.0 * -0.0 == 0.0.
4323  Value *X;
4324  if (Op0 == Op1 && match(Op0, m_Intrinsic<Intrinsic::sqrt>(m_Value(X))) &&
4325  FMF.allowReassoc() && FMF.noNaNs() && FMF.noSignedZeros())
4326  return X;
4327 
4328  return nullptr;
4329 }
4330 
4332  const SimplifyQuery &Q) {
4333  return ::SimplifyFAddInst(Op0, Op1, FMF, Q, RecursionLimit);
4334 }
4335 
4336 
4338  const SimplifyQuery &Q) {
4339  return ::SimplifyFSubInst(Op0, Op1, FMF, Q, RecursionLimit);
4340 }
4341 
4343  const SimplifyQuery &Q) {
4344  return ::SimplifyFMulInst(Op0, Op1, FMF, Q, RecursionLimit);
4345 }
4346 
4348  const SimplifyQuery &Q, unsigned) {
4349  if (Constant *C = foldOrCommuteConstant(Instruction::FDiv, Op0, Op1, Q))
4350  return C;
4351 
4352  if (Constant *C = simplifyFPBinop(Op0, Op1))
4353  return C;
4354 
4355  // X / 1.0 -> X
4356  if (match(Op1, m_FPOne()))
4357  return Op0;
4358 
4359  // 0 / X -> 0
4360  // Requires that NaNs are off (X could be zero) and signed zeroes are
4361  // ignored (X could be positive or negative, so the output sign is unknown).
4362  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZeroFP()))
4363  return ConstantFP::getNullValue(Op0->getType());
4364 
4365  if (FMF.noNaNs()) {
4366  // X / X -> 1.0 is legal when NaNs are ignored.
4367  // We can ignore infinities because INF/INF is NaN.
4368  if (Op0 == Op1)
4369  return ConstantFP::get(Op0->getType(), 1.0);
4370 
4371  // (X * Y) / Y --> X if we can reassociate to the above form.
4372  Value *X;
4373  if (FMF.allowReassoc() && match(Op0, m_c_FMul(m_Value(X), m_Specific(Op1))))
4374  return X;
4375 
4376  // -X / X -> -1.0 and
4377  // X / -X -> -1.0 are legal when NaNs are ignored.
4378  // We can ignore signed zeros because +-0.0/+-0.0 is NaN and ignored.
4379  if ((BinaryOperator::isFNeg(Op0, /*IgnoreZeroSign=*/true) &&
4380  BinaryOperator::getFNegArgument(Op0) == Op1) ||
4381  (BinaryOperator::isFNeg(Op1, /*IgnoreZeroSign=*/true) &&
4382  BinaryOperator::getFNegArgument(Op1) == Op0))
4383  return ConstantFP::get(Op0->getType(), -1.0);
4384  }
4385 
4386  return nullptr;
4387 }
4388 
4390  const SimplifyQuery &Q) {
4391  return ::SimplifyFDivInst(Op0, Op1, FMF, Q, RecursionLimit);
4392 }
4393 
4395  const SimplifyQuery &Q, unsigned) {
4396  if (Constant *C = foldOrCommuteConstant(Instruction::FRem, Op0, Op1, Q))
4397  return C;
4398 
4399  if (Constant *C = simplifyFPBinop(Op0, Op1))
4400  return C;
4401 
4402  // Unlike fdiv, the result of frem always matches the sign of the dividend.
4403  // The constant match may include undef elements in a vector, so return a full
4404  // zero constant as the result.
4405  if (FMF.noNaNs()) {
4406  // +0 % X -> 0
4407  if (match(Op0, m_PosZeroFP()))
4408  return ConstantFP::getNullValue(Op0->getType());
4409  // -0 % X -> -0
4410  if (match(Op0, m_NegZeroFP()))
4411  return ConstantFP::getNegativeZero(Op0->getType());
4412  }
4413 
4414  return nullptr;
4415 }
4416 
4418  const SimplifyQuery &Q) {
4419  return ::SimplifyFRemInst(Op0, Op1, FMF, Q, RecursionLimit);
4420 }
4421 
4422 //=== Helper functions for higher up the class hierarchy.
4423 
4424 /// Given operands for a BinaryOperator, see if we can fold the result.
4425 /// If not, this returns null.
4426 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4427  const SimplifyQuery &Q, unsigned MaxRecurse) {
4428  switch (Opcode) {
4429  case Instruction::Add:
4430  return SimplifyAddInst(LHS, RHS, false, false, Q, MaxRecurse);
4431  case Instruction::Sub:
4432  return SimplifySubInst(LHS, RHS, false, false, Q, MaxRecurse);
4433  case Instruction::Mul:
4434  return SimplifyMulInst(LHS, RHS, Q, MaxRecurse);
4435  case Instruction::SDiv:
4436  return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
4437  case Instruction::UDiv:
4438  return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
4439  case Instruction::SRem:
4440  return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
4441  case Instruction::URem:
4442  return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
4443  case Instruction::Shl:
4444  return SimplifyShlInst(LHS, RHS, false, false, Q, MaxRecurse);
4445  case Instruction::LShr:
4446  return SimplifyLShrInst(LHS, RHS, false, Q, MaxRecurse);
4447  case Instruction::AShr:
4448  return SimplifyAShrInst(LHS, RHS, false, Q, MaxRecurse);
4449  case Instruction::And:
4450  return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
4451  case Instruction::Or:
4452  return SimplifyOrInst(LHS, RHS, Q, MaxRecurse);
4453  case Instruction::Xor:
4454  return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
4455  case Instruction::FAdd:
4456  return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4457  case Instruction::FSub:
4458  return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4459  case Instruction::FMul:
4460  return SimplifyFMulInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4461  case Instruction::FDiv:
4462  return SimplifyFDivInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4463  case Instruction::FRem:
4464  return SimplifyFRemInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4465  default:
4466  llvm_unreachable("Unexpected opcode");
4467  }
4468 }
4469 
4470 /// Given operands for a BinaryOperator, see if we can fold the result.
4471 /// If not, this returns null.
4472 /// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the
4473 /// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp.
4474 static Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4475  const FastMathFlags &FMF, const SimplifyQuery &Q,
4476  unsigned MaxRecurse) {
4477  switch (Opcode) {
4478  case Instruction::FAdd:
4479  return SimplifyFAddInst(LHS, RHS, FMF, Q, MaxRecurse);
4480  case Instruction::FSub:
4481  return SimplifyFSubInst(LHS, RHS, FMF, Q, MaxRecurse);
4482  case Instruction::FMul:
4483  return SimplifyFMulInst(LHS, RHS, FMF, Q, MaxRecurse);
4484  case Instruction::FDiv:
4485  return SimplifyFDivInst(LHS, RHS, FMF, Q, MaxRecurse);
4486  default:
4487  return SimplifyBinOp(Opcode, LHS, RHS, Q, MaxRecurse);
4488  }
4489 }
4490 
4491 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4492  const SimplifyQuery &Q) {
4493  return ::SimplifyBinOp(Opcode, LHS, RHS, Q, RecursionLimit);
4494 }
4495 
4496 Value *llvm::SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4497  FastMathFlags FMF, const SimplifyQuery &Q) {
4498  return ::SimplifyFPBinOp(Opcode, LHS, RHS, FMF, Q, RecursionLimit);
4499 }
4500 
4501 /// Given operands for a CmpInst, see if we can fold the result.
4502 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
4503  const SimplifyQuery &Q, unsigned MaxRecurse) {
4505  return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
4506  return SimplifyFCmpInst(Predicate, LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4507 }
4508 
4509 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
4510  const SimplifyQuery &Q) {
4511  return ::SimplifyCmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
4512 }
4513 
4515  switch (ID) {
4516  default: return false;
4517 
4518  // Unary idempotent: f(f(x)) = f(x)
4519  case Intrinsic::fabs:
4520  case Intrinsic::floor:
4521  case Intrinsic::ceil:
4522  case Intrinsic::trunc:
4523  case Intrinsic::rint:
4524  case Intrinsic::nearbyint:
4525  case Intrinsic::round:
4526  case Intrinsic::canonicalize:
4527  return true;
4528  }
4529 }
4530 
4532  const DataLayout &DL) {
4533  GlobalValue *PtrSym;
4534  APInt PtrOffset;
4535  if (!IsConstantOffsetFromGlobal(Ptr, PtrSym, PtrOffset, DL))
4536  return nullptr;
4537 
4538  Type *Int8PtrTy = Type::getInt8PtrTy(Ptr->getContext());
4540  Type *Int32PtrTy = Int32Ty->getPointerTo();
4541  Type *Int64Ty = Type::getInt64Ty(Ptr->getContext());
4542 
4543  auto *OffsetConstInt = dyn_cast<ConstantInt>(Offset);
4544  if (!OffsetConstInt || OffsetConstInt->getType()->getBitWidth() > 64)
4545  return nullptr;
4546 
4547  uint64_t OffsetInt = OffsetConstInt->getSExtValue();
4548  if (OffsetInt % 4 != 0)
4549  return nullptr;
4550 
4552  Int32Ty, ConstantExpr::getBitCast(Ptr, Int32PtrTy),
4553  ConstantInt::get(Int64Ty, OffsetInt / 4));
4554  Constant *Loaded = ConstantFoldLoadFromConstPtr(C, Int32Ty, DL);
4555  if (!Loaded)
4556  return nullptr;
4557 
4558  auto *LoadedCE = dyn_cast<ConstantExpr>(Loaded);
4559  if (!LoadedCE)
4560  return nullptr;
4561 
4562  if (LoadedCE->getOpcode() == Instruction::Trunc) {
4563  LoadedCE = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4564  if (!LoadedCE)
4565  return nullptr;
4566  }
4567 
4568  if (LoadedCE->getOpcode() != Instruction::Sub)
4569  return nullptr;
4570 
4571  auto *LoadedLHS = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4572  if (!LoadedLHS || LoadedLHS->getOpcode() != Instruction::PtrToInt)
4573  return nullptr;
4574  auto *LoadedLHSPtr = LoadedLHS->getOperand(0);
4575 
4576  Constant *LoadedRHS = LoadedCE->getOperand(1);
4577  GlobalValue *LoadedRHSSym;
4578  APInt LoadedRHSOffset;
4579  if (!IsConstantOffsetFromGlobal(LoadedRHS, LoadedRHSSym, LoadedRHSOffset,
4580  DL) ||
4581  PtrSym != LoadedRHSSym || PtrOffset != LoadedRHSOffset)
4582  return nullptr;
4583 
4584  return ConstantExpr::getBitCast(LoadedLHSPtr, Int8PtrTy);
4585 }
4586 
4588  auto *ConstMask = dyn_cast<Constant>(Mask);
4589  if (!ConstMask)
4590  return false;
4591  if (ConstMask->isNullValue() || isa<UndefValue>(ConstMask))
4592  return true;
4593  for (unsigned I = 0, E = ConstMask->getType()->getVectorNumElements(); I != E;
4594  ++I) {
4595  if (auto *MaskElt = ConstMask->getAggregateElement(I))
4596  if (MaskElt->isNullValue() || isa<UndefValue>(MaskElt))
4597  continue;
4598  return false;
4599  }
4600  return true;
4601 }
4602 
4603 template <typename IterTy>
4604 static Value *SimplifyIntrinsic(Function *F, IterTy ArgBegin, IterTy ArgEnd,
4605  const SimplifyQuery &Q, unsigned MaxRecurse) {
4606  Intrinsic::ID IID = F->getIntrinsicID();
4607  unsigned NumOperands = std::distance(ArgBegin, ArgEnd);
4608 
4609  // Unary Ops
4610  if (NumOperands == 1) {
4611  // Perform idempotent optimizations
4612  if (IsIdempotent(IID)) {
4613  if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin)) {
4614  if (II->getIntrinsicID() == IID)
4615  return II;
4616  }
4617  }
4618 
4619  Value *IIOperand = *ArgBegin;
4620  Value *X;
4621  switch (IID) {
4622  case Intrinsic::fabs: {
4623  if (SignBitMustBeZero(IIOperand, Q.TLI))
4624  return IIOperand;
4625  return nullptr;
4626  }
4627  case Intrinsic::bswap: {
4628  // bswap(bswap(x)) -> x
4629  if (match(IIOperand, m_BSwap(m_Value(X))))
4630  return X;
4631  return nullptr;
4632  }
4633  case Intrinsic::bitreverse: {
4634  // bitreverse(bitreverse(x)) -> x
4635  if (match(IIOperand, m_BitReverse(m_Value(X))))
4636  return X;
4637  return nullptr;
4638  }
4639  case Intrinsic::exp: {
4640  // exp(log(x)) -> x
4641  if (Q.CxtI->hasAllowReassoc() &&
4642  match(IIOperand, m_Intrinsic<Intrinsic::log>(m_Value(X))))
4643  return X;
4644  return nullptr;
4645  }
4646  case Intrinsic::exp2: {
4647  // exp2(log2(x)) -> x
4648  if (Q.CxtI->hasAllowReassoc() &&
4649  match(IIOperand, m_Intrinsic<Intrinsic::log2>(m_Value(X))))
4650  return X;
4651  return nullptr;
4652  }
4653  case Intrinsic::log: {
4654  // log(exp(x)) -> x
4655  if (Q.CxtI->hasAllowReassoc() &&
4656  match(IIOperand, m_Intrinsic<Intrinsic::exp>(m_Value(X))))
4657  return X;
4658  return nullptr;
4659  }
4660  case Intrinsic::log2: {
4661  // log2(exp2(x)) -> x
4662  if (Q.CxtI->hasAllowReassoc() &&
4663  match(IIOperand, m_Intrinsic<Intrinsic::exp2>(m_Value(X)))) {
4664  return X;
4665  }
4666  return nullptr;
4667  }
4668  default:
4669  return nullptr;
4670  }
4671  }
4672 
4673  // Binary Ops
4674  if (NumOperands == 2) {
4675  Value *LHS = *ArgBegin;
4676  Value *RHS = *(ArgBegin + 1);
4677  Type *ReturnType = F->getReturnType();
4678 
4679  switch (IID) {
4680  case Intrinsic::usub_with_overflow:
4681  case Intrinsic::ssub_with_overflow: {
4682  // X - X -> { 0, false }
4683  if (LHS == RHS)
4684  return Constant::getNullValue(ReturnType);
4685 
4686  // X - undef -> undef
4687  // undef - X -> undef
4688  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
4689  return UndefValue::get(ReturnType);
4690 
4691  return nullptr;
4692  }
4693  case Intrinsic::uadd_with_overflow:
4694  case Intrinsic::sadd_with_overflow: {
4695  // X + undef -> undef
4696  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
4697  return UndefValue::get(ReturnType);
4698 
4699  return nullptr;
4700  }
4701  case Intrinsic::umul_with_overflow:
4702  case Intrinsic::smul_with_overflow: {
4703  // 0 * X -> { 0, false }
4704  // X * 0 -> { 0, false }
4705  if (match(LHS, m_Zero()) || match(RHS, m_Zero()))
4706  return Constant::getNullValue(ReturnType);
4707 
4708  // undef * X -> { 0, false }
4709  // X * undef -> { 0, false }
4710  if (match(LHS, m_Undef()) || match(RHS, m_Undef()))
4711  return Constant::getNullValue(ReturnType);
4712 
4713  return nullptr;
4714  }
4715  case Intrinsic::load_relative: {
4716  Constant *C0 = dyn_cast<Constant>(LHS);
4717  Constant *C1 = dyn_cast<Constant>(RHS);
4718  if (C0 && C1)
4719  return SimplifyRelativeLoad(C0, C1, Q.DL);
4720  return nullptr;
4721  }
4722  case Intrinsic::powi:
4723  if (ConstantInt *Power = dyn_cast<ConstantInt>(RHS)) {
4724  // powi(x, 0) -> 1.0
4725  if (Power->isZero())
4726  return ConstantFP::get(LHS->getType(), 1.0);
4727  // powi(x, 1) -> x
4728  if (Power->isOne())
4729  return LHS;
4730  }
4731  return nullptr;
4732  case Intrinsic::maxnum:
4733  case Intrinsic::minnum:
4734  // If one argument is NaN, return the other argument.
4735  if (match(LHS, m_NaN()))
4736  return RHS;
4737  if (match(RHS, m_NaN()))
4738  return LHS;
4739  return nullptr;
4740  default:
4741  return nullptr;
4742  }
4743  }
4744 
4745  // Simplify calls to llvm.masked.load.*
4746  switch (IID) {
4747  case Intrinsic::masked_load: {
4748  Value *MaskArg = ArgBegin[2];
4749  Value *PassthruArg = ArgBegin[3];
4750  // If the mask is all zeros or undef, the "passthru" argument is the result.
4751  if (maskIsAllZeroOrUndef(MaskArg))
4752  return PassthruArg;
4753  return nullptr;
4754  }
4755  default:
4756  return nullptr;
4757  }
4758 }
4759 
4760 template <typename IterTy>
4761 static Value *SimplifyCall(ImmutableCallSite CS, Value *V, IterTy ArgBegin,
4762  IterTy ArgEnd, const SimplifyQuery &Q,
4763  unsigned MaxRecurse) {
4764  Type *Ty = V->getType();
4765  if (PointerType *PTy = dyn_cast<PointerType>(Ty))
4766  Ty = PTy->getElementType();
4767  FunctionType *FTy = cast<FunctionType>(Ty);
4768 
4769  // call undef -> undef
4770  // call null -> undef
4771  if (isa<UndefValue>(V) || isa<ConstantPointerNull>(V))
4772  return UndefValue::get(FTy->getReturnType());
4773 
4774  Function *F = dyn_cast<Function>(V);
4775  if (!F)
4776  return nullptr;
4777 
4778  if (F->isIntrinsic())
4779  if (Value *Ret = SimplifyIntrinsic(F, ArgBegin, ArgEnd, Q, MaxRecurse))
4780  return Ret;
4781 
4782  if (!canConstantFoldCallTo(CS, F))
4783  return nullptr;
4784 
4785  SmallVector<Constant *, 4> ConstantArgs;
4786  ConstantArgs.reserve(ArgEnd - ArgBegin);
4787  for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
4788  Constant *C = dyn_cast<Constant>(*I);
4789  if (!C)
4790  return nullptr;
4791  ConstantArgs.push_back(C);
4792  }
4793 
4794  return ConstantFoldCall(CS, F, ConstantArgs, Q.TLI);
4795 }
4796 
4798  User::op_iterator ArgBegin, User::op_iterator ArgEnd,
4799  const SimplifyQuery &Q) {
4800  return ::SimplifyCall(CS, V, ArgBegin, ArgEnd, Q, RecursionLimit);
4801 }
4802 
4804  ArrayRef<Value *> Args, const SimplifyQuery &Q) {
4805  return ::SimplifyCall(CS, V, Args.begin(), Args.end(), Q, RecursionLimit);
4806 }
4807 
4809  CallSite CS(const_cast<Instruction*>(ICS.getInstruction()));
4811  Q, RecursionLimit);
4812 }
4813 
4814 /// See if we can compute a simplified version of this instruction.
4815 /// If not, this returns null.
4816 
4819  const SimplifyQuery Q = SQ.CxtI ? SQ : SQ.getWithInstruction(I);
4820  Value *Result;
4821 
4822  switch (I->getOpcode()) {
4823  default:
4824  Result = ConstantFoldInstruction(I, Q.DL, Q.TLI);
4825  break;
4826  case Instruction::FAdd:
4827  Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
4828  I->getFastMathFlags(), Q);
4829  break;
4830  case Instruction::Add:
4831  Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
4832  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4833  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4834  break;
4835  case Instruction::FSub:
4836  Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
4837  I->getFastMathFlags(), Q);
4838  break;
4839  case Instruction::Sub:
4840  Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
4841  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4842  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4843  break;
4844  case Instruction::FMul:
4845  Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
4846  I->getFastMathFlags(), Q);
4847  break;
4848  case Instruction::Mul:
4849  Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), Q);
4850  break;
4851  case Instruction::SDiv:
4852  Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), Q);
4853  break;
4854  case Instruction::UDiv:
4855  Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), Q);
4856  break;
4857  case Instruction::FDiv:
4858  Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1),
4859  I->getFastMathFlags(), Q);
4860  break;
4861  case Instruction::SRem:
4862  Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), Q);
4863  break;
4864  case Instruction::URem:
4865  Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), Q);
4866  break;
4867  case Instruction::FRem:
4868  Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1),
4869  I->getFastMathFlags(), Q);
4870  break;
4871  case Instruction::Shl: