LLVM  6.0.0svn
InstructionSimplify.cpp
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1 //===- InstructionSimplify.cpp - Fold instruction operands ----------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements routines for folding instructions into simpler forms
11 // that do not require creating new instructions. This does constant folding
12 // ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
13 // returning a constant ("and i32 %x, 0" -> "0") or an already existing value
14 // ("and i32 %x, %x" -> "%x"). All operands are assumed to have already been
15 // simplified: This is usually true and assuming it simplifies the logic (if
16 // they have not been simplified then results are correct but maybe suboptimal).
17 //
18 //===----------------------------------------------------------------------===//
19 
21 #include "llvm/ADT/SetVector.h"
22 #include "llvm/ADT/Statistic.h"
33 #include "llvm/IR/ConstantRange.h"
34 #include "llvm/IR/DataLayout.h"
35 #include "llvm/IR/Dominators.h"
37 #include "llvm/IR/GlobalAlias.h"
38 #include "llvm/IR/Operator.h"
39 #include "llvm/IR/PatternMatch.h"
40 #include "llvm/IR/ValueHandle.h"
41 #include "llvm/Support/KnownBits.h"
42 #include <algorithm>
43 using namespace llvm;
44 using namespace llvm::PatternMatch;
45 
46 #define DEBUG_TYPE "instsimplify"
47 
48 enum { RecursionLimit = 3 };
49 
50 STATISTIC(NumExpand, "Number of expansions");
51 STATISTIC(NumReassoc, "Number of reassociations");
52 
53 static Value *SimplifyAndInst(Value *, Value *, const SimplifyQuery &, unsigned);
54 static Value *SimplifyBinOp(unsigned, Value *, Value *, const SimplifyQuery &,
55  unsigned);
56 static Value *SimplifyFPBinOp(unsigned, Value *, Value *, const FastMathFlags &,
57  const SimplifyQuery &, unsigned);
58 static Value *SimplifyCmpInst(unsigned, Value *, Value *, const SimplifyQuery &,
59  unsigned);
60 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
61  const SimplifyQuery &Q, unsigned MaxRecurse);
62 static Value *SimplifyOrInst(Value *, Value *, const SimplifyQuery &, unsigned);
63 static Value *SimplifyXorInst(Value *, Value *, const SimplifyQuery &, unsigned);
64 static Value *SimplifyCastInst(unsigned, Value *, Type *,
65  const SimplifyQuery &, unsigned);
66 
67 /// For a boolean type or a vector of boolean type, return false or a vector
68 /// with every element false.
69 static Constant *getFalse(Type *Ty) {
70  return ConstantInt::getFalse(Ty);
71 }
72 
73 /// For a boolean type or a vector of boolean type, return true or a vector
74 /// with every element true.
75 static Constant *getTrue(Type *Ty) {
76  return ConstantInt::getTrue(Ty);
77 }
78 
79 /// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
80 static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
81  Value *RHS) {
82  CmpInst *Cmp = dyn_cast<CmpInst>(V);
83  if (!Cmp)
84  return false;
85  CmpInst::Predicate CPred = Cmp->getPredicate();
86  Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
87  if (CPred == Pred && CLHS == LHS && CRHS == RHS)
88  return true;
89  return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
90  CRHS == LHS;
91 }
92 
93 /// Does the given value dominate the specified phi node?
94 static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
96  if (!I)
97  // Arguments and constants dominate all instructions.
98  return true;
99 
100  // If we are processing instructions (and/or basic blocks) that have not been
101  // fully added to a function, the parent nodes may still be null. Simply
102  // return the conservative answer in these cases.
103  if (!I->getParent() || !P->getParent() || !I->getParent()->getParent())
104  return false;
105 
106  // If we have a DominatorTree then do a precise test.
107  if (DT)
108  return DT->dominates(I, P);
109 
110  // Otherwise, if the instruction is in the entry block and is not an invoke,
111  // then it obviously dominates all phi nodes.
112  if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
113  !isa<InvokeInst>(I))
114  return true;
115 
116  return false;
117 }
118 
119 /// Simplify "A op (B op' C)" by distributing op over op', turning it into
120 /// "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
121 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
122 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
123 /// Returns the simplified value, or null if no simplification was performed.
125  Instruction::BinaryOps OpcodeToExpand,
126  const SimplifyQuery &Q, unsigned MaxRecurse) {
127  // Recursion is always used, so bail out at once if we already hit the limit.
128  if (!MaxRecurse--)
129  return nullptr;
130 
131  // Check whether the expression has the form "(A op' B) op C".
132  if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
133  if (Op0->getOpcode() == OpcodeToExpand) {
134  // It does! Try turning it into "(A op C) op' (B op C)".
135  Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
136  // Do "A op C" and "B op C" both simplify?
137  if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
138  if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
139  // They do! Return "L op' R" if it simplifies or is already available.
140  // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
141  if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
142  && L == B && R == A)) {
143  ++NumExpand;
144  return LHS;
145  }
146  // Otherwise return "L op' R" if it simplifies.
147  if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
148  ++NumExpand;
149  return V;
150  }
151  }
152  }
153 
154  // Check whether the expression has the form "A op (B op' C)".
155  if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
156  if (Op1->getOpcode() == OpcodeToExpand) {
157  // It does! Try turning it into "(A op B) op' (A op C)".
158  Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
159  // Do "A op B" and "A op C" both simplify?
160  if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
161  if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
162  // They do! Return "L op' R" if it simplifies or is already available.
163  // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
164  if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
165  && L == C && R == B)) {
166  ++NumExpand;
167  return RHS;
168  }
169  // Otherwise return "L op' R" if it simplifies.
170  if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
171  ++NumExpand;
172  return V;
173  }
174  }
175  }
176 
177  return nullptr;
178 }
179 
180 /// Generic simplifications for associative binary operations.
181 /// Returns the simpler value, or null if none was found.
183  Value *LHS, Value *RHS,
184  const SimplifyQuery &Q,
185  unsigned MaxRecurse) {
186  assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
187 
188  // Recursion is always used, so bail out at once if we already hit the limit.
189  if (!MaxRecurse--)
190  return nullptr;
191 
194 
195  // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
196  if (Op0 && Op0->getOpcode() == Opcode) {
197  Value *A = Op0->getOperand(0);
198  Value *B = Op0->getOperand(1);
199  Value *C = RHS;
200 
201  // Does "B op C" simplify?
202  if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
203  // It does! Return "A op V" if it simplifies or is already available.
204  // If V equals B then "A op V" is just the LHS.
205  if (V == B) return LHS;
206  // Otherwise return "A op V" if it simplifies.
207  if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
208  ++NumReassoc;
209  return W;
210  }
211  }
212  }
213 
214  // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
215  if (Op1 && Op1->getOpcode() == Opcode) {
216  Value *A = LHS;
217  Value *B = Op1->getOperand(0);
218  Value *C = Op1->getOperand(1);
219 
220  // Does "A op B" simplify?
221  if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
222  // It does! Return "V op C" if it simplifies or is already available.
223  // If V equals B then "V op C" is just the RHS.
224  if (V == B) return RHS;
225  // Otherwise return "V op C" if it simplifies.
226  if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
227  ++NumReassoc;
228  return W;
229  }
230  }
231  }
232 
233  // The remaining transforms require commutativity as well as associativity.
234  if (!Instruction::isCommutative(Opcode))
235  return nullptr;
236 
237  // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
238  if (Op0 && Op0->getOpcode() == Opcode) {
239  Value *A = Op0->getOperand(0);
240  Value *B = Op0->getOperand(1);
241  Value *C = RHS;
242 
243  // Does "C op A" simplify?
244  if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
245  // It does! Return "V op B" if it simplifies or is already available.
246  // If V equals A then "V op B" is just the LHS.
247  if (V == A) return LHS;
248  // Otherwise return "V op B" if it simplifies.
249  if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
250  ++NumReassoc;
251  return W;
252  }
253  }
254  }
255 
256  // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
257  if (Op1 && Op1->getOpcode() == Opcode) {
258  Value *A = LHS;
259  Value *B = Op1->getOperand(0);
260  Value *C = Op1->getOperand(1);
261 
262  // Does "C op A" simplify?
263  if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
264  // It does! Return "B op V" if it simplifies or is already available.
265  // If V equals C then "B op V" is just the RHS.
266  if (V == C) return RHS;
267  // Otherwise return "B op V" if it simplifies.
268  if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
269  ++NumReassoc;
270  return W;
271  }
272  }
273  }
274 
275  return nullptr;
276 }
277 
278 /// In the case of a binary operation with a select instruction as an operand,
279 /// try to simplify the binop by seeing whether evaluating it on both branches
280 /// of the select results in the same value. Returns the common value if so,
281 /// otherwise returns null.
283  Value *RHS, const SimplifyQuery &Q,
284  unsigned MaxRecurse) {
285  // Recursion is always used, so bail out at once if we already hit the limit.
286  if (!MaxRecurse--)
287  return nullptr;
288 
289  SelectInst *SI;
290  if (isa<SelectInst>(LHS)) {
291  SI = cast<SelectInst>(LHS);
292  } else {
293  assert(isa<SelectInst>(RHS) && "No select instruction operand!");
294  SI = cast<SelectInst>(RHS);
295  }
296 
297  // Evaluate the BinOp on the true and false branches of the select.
298  Value *TV;
299  Value *FV;
300  if (SI == LHS) {
301  TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
302  FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
303  } else {
304  TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
305  FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
306  }
307 
308  // If they simplified to the same value, then return the common value.
309  // If they both failed to simplify then return null.
310  if (TV == FV)
311  return TV;
312 
313  // If one branch simplified to undef, return the other one.
314  if (TV && isa<UndefValue>(TV))
315  return FV;
316  if (FV && isa<UndefValue>(FV))
317  return TV;
318 
319  // If applying the operation did not change the true and false select values,
320  // then the result of the binop is the select itself.
321  if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
322  return SI;
323 
324  // If one branch simplified and the other did not, and the simplified
325  // value is equal to the unsimplified one, return the simplified value.
326  // For example, select (cond, X, X & Z) & Z -> X & Z.
327  if ((FV && !TV) || (TV && !FV)) {
328  // Check that the simplified value has the form "X op Y" where "op" is the
329  // same as the original operation.
330  Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
331  if (Simplified && Simplified->getOpcode() == Opcode) {
332  // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
333  // We already know that "op" is the same as for the simplified value. See
334  // if the operands match too. If so, return the simplified value.
335  Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
336  Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
337  Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
338  if (Simplified->getOperand(0) == UnsimplifiedLHS &&
339  Simplified->getOperand(1) == UnsimplifiedRHS)
340  return Simplified;
341  if (Simplified->isCommutative() &&
342  Simplified->getOperand(1) == UnsimplifiedLHS &&
343  Simplified->getOperand(0) == UnsimplifiedRHS)
344  return Simplified;
345  }
346  }
347 
348  return nullptr;
349 }
350 
351 /// In the case of a comparison with a select instruction, try to simplify the
352 /// comparison by seeing whether both branches of the select result in the same
353 /// value. Returns the common value if so, otherwise returns null.
355  Value *RHS, const SimplifyQuery &Q,
356  unsigned MaxRecurse) {
357  // Recursion is always used, so bail out at once if we already hit the limit.
358  if (!MaxRecurse--)
359  return nullptr;
360 
361  // Make sure the select is on the LHS.
362  if (!isa<SelectInst>(LHS)) {
363  std::swap(LHS, RHS);
364  Pred = CmpInst::getSwappedPredicate(Pred);
365  }
366  assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
367  SelectInst *SI = cast<SelectInst>(LHS);
368  Value *Cond = SI->getCondition();
369  Value *TV = SI->getTrueValue();
370  Value *FV = SI->getFalseValue();
371 
372  // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
373  // Does "cmp TV, RHS" simplify?
374  Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
375  if (TCmp == Cond) {
376  // It not only simplified, it simplified to the select condition. Replace
377  // it with 'true'.
378  TCmp = getTrue(Cond->getType());
379  } else if (!TCmp) {
380  // It didn't simplify. However if "cmp TV, RHS" is equal to the select
381  // condition then we can replace it with 'true'. Otherwise give up.
382  if (!isSameCompare(Cond, Pred, TV, RHS))
383  return nullptr;
384  TCmp = getTrue(Cond->getType());
385  }
386 
387  // Does "cmp FV, RHS" simplify?
388  Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
389  if (FCmp == Cond) {
390  // It not only simplified, it simplified to the select condition. Replace
391  // it with 'false'.
392  FCmp = getFalse(Cond->getType());
393  } else if (!FCmp) {
394  // It didn't simplify. However if "cmp FV, RHS" is equal to the select
395  // condition then we can replace it with 'false'. Otherwise give up.
396  if (!isSameCompare(Cond, Pred, FV, RHS))
397  return nullptr;
398  FCmp = getFalse(Cond->getType());
399  }
400 
401  // If both sides simplified to the same value, then use it as the result of
402  // the original comparison.
403  if (TCmp == FCmp)
404  return TCmp;
405 
406  // The remaining cases only make sense if the select condition has the same
407  // type as the result of the comparison, so bail out if this is not so.
408  if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
409  return nullptr;
410  // If the false value simplified to false, then the result of the compare
411  // is equal to "Cond && TCmp". This also catches the case when the false
412  // value simplified to false and the true value to true, returning "Cond".
413  if (match(FCmp, m_Zero()))
414  if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
415  return V;
416  // If the true value simplified to true, then the result of the compare
417  // is equal to "Cond || FCmp".
418  if (match(TCmp, m_One()))
419  if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
420  return V;
421  // Finally, if the false value simplified to true and the true value to
422  // false, then the result of the compare is equal to "!Cond".
423  if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
424  if (Value *V =
425  SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
426  Q, MaxRecurse))
427  return V;
428 
429  return nullptr;
430 }
431 
432 /// In the case of a binary operation with an operand that is a PHI instruction,
433 /// try to simplify the binop by seeing whether evaluating it on the incoming
434 /// phi values yields the same result for every value. If so returns the common
435 /// value, otherwise returns null.
437  Value *RHS, const SimplifyQuery &Q,
438  unsigned MaxRecurse) {
439  // Recursion is always used, so bail out at once if we already hit the limit.
440  if (!MaxRecurse--)
441  return nullptr;
442 
443  PHINode *PI;
444  if (isa<PHINode>(LHS)) {
445  PI = cast<PHINode>(LHS);
446  // Bail out if RHS and the phi may be mutually interdependent due to a loop.
447  if (!ValueDominatesPHI(RHS, PI, Q.DT))
448  return nullptr;
449  } else {
450  assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
451  PI = cast<PHINode>(RHS);
452  // Bail out if LHS and the phi may be mutually interdependent due to a loop.
453  if (!ValueDominatesPHI(LHS, PI, Q.DT))
454  return nullptr;
455  }
456 
457  // Evaluate the BinOp on the incoming phi values.
458  Value *CommonValue = nullptr;
459  for (Value *Incoming : PI->incoming_values()) {
460  // If the incoming value is the phi node itself, it can safely be skipped.
461  if (Incoming == PI) continue;
462  Value *V = PI == LHS ?
463  SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
464  SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
465  // If the operation failed to simplify, or simplified to a different value
466  // to previously, then give up.
467  if (!V || (CommonValue && V != CommonValue))
468  return nullptr;
469  CommonValue = V;
470  }
471 
472  return CommonValue;
473 }
474 
475 /// In the case of a comparison with a PHI instruction, try to simplify the
476 /// comparison by seeing whether comparing with all of the incoming phi values
477 /// yields the same result every time. If so returns the common result,
478 /// otherwise returns null.
480  const SimplifyQuery &Q, unsigned MaxRecurse) {
481  // Recursion is always used, so bail out at once if we already hit the limit.
482  if (!MaxRecurse--)
483  return nullptr;
484 
485  // Make sure the phi is on the LHS.
486  if (!isa<PHINode>(LHS)) {
487  std::swap(LHS, RHS);
488  Pred = CmpInst::getSwappedPredicate(Pred);
489  }
490  assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
491  PHINode *PI = cast<PHINode>(LHS);
492 
493  // Bail out if RHS and the phi may be mutually interdependent due to a loop.
494  if (!ValueDominatesPHI(RHS, PI, Q.DT))
495  return nullptr;
496 
497  // Evaluate the BinOp on the incoming phi values.
498  Value *CommonValue = nullptr;
499  for (Value *Incoming : PI->incoming_values()) {
500  // If the incoming value is the phi node itself, it can safely be skipped.
501  if (Incoming == PI) continue;
502  Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
503  // If the operation failed to simplify, or simplified to a different value
504  // to previously, then give up.
505  if (!V || (CommonValue && V != CommonValue))
506  return nullptr;
507  CommonValue = V;
508  }
509 
510  return CommonValue;
511 }
512 
514  Value *&Op0, Value *&Op1,
515  const SimplifyQuery &Q) {
516  if (auto *CLHS = dyn_cast<Constant>(Op0)) {
517  if (auto *CRHS = dyn_cast<Constant>(Op1))
518  return ConstantFoldBinaryOpOperands(Opcode, CLHS, CRHS, Q.DL);
519 
520  // Canonicalize the constant to the RHS if this is a commutative operation.
521  if (Instruction::isCommutative(Opcode))
522  std::swap(Op0, Op1);
523  }
524  return nullptr;
525 }
526 
527 /// Given operands for an Add, see if we can fold the result.
528 /// If not, this returns null.
529 static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
530  const SimplifyQuery &Q, unsigned MaxRecurse) {
531  if (Constant *C = foldOrCommuteConstant(Instruction::Add, Op0, Op1, Q))
532  return C;
533 
534  // X + undef -> undef
535  if (match(Op1, m_Undef()))
536  return Op1;
537 
538  // X + 0 -> X
539  if (match(Op1, m_Zero()))
540  return Op0;
541 
542  // X + (Y - X) -> Y
543  // (Y - X) + X -> Y
544  // Eg: X + -X -> 0
545  Value *Y = nullptr;
546  if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
547  match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
548  return Y;
549 
550  // X + ~X -> -1 since ~X = -X-1
551  Type *Ty = Op0->getType();
552  if (match(Op0, m_Not(m_Specific(Op1))) ||
553  match(Op1, m_Not(m_Specific(Op0))))
554  return Constant::getAllOnesValue(Ty);
555 
556  // add nsw/nuw (xor Y, signmask), signmask --> Y
557  // The no-wrapping add guarantees that the top bit will be set by the add.
558  // Therefore, the xor must be clearing the already set sign bit of Y.
559  if ((isNSW || isNUW) && match(Op1, m_SignMask()) &&
560  match(Op0, m_Xor(m_Value(Y), m_SignMask())))
561  return Y;
562 
563  /// i1 add -> xor.
564  if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
565  if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
566  return V;
567 
568  // Try some generic simplifications for associative operations.
569  if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
570  MaxRecurse))
571  return V;
572 
573  // Threading Add over selects and phi nodes is pointless, so don't bother.
574  // Threading over the select in "A + select(cond, B, C)" means evaluating
575  // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
576  // only if B and C are equal. If B and C are equal then (since we assume
577  // that operands have already been simplified) "select(cond, B, C)" should
578  // have been simplified to the common value of B and C already. Analysing
579  // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
580  // for threading over phi nodes.
581 
582  return nullptr;
583 }
584 
585 Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
586  const SimplifyQuery &Query) {
587  return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, Query, RecursionLimit);
588 }
589 
590 /// \brief Compute the base pointer and cumulative constant offsets for V.
591 ///
592 /// This strips all constant offsets off of V, leaving it the base pointer, and
593 /// accumulates the total constant offset applied in the returned constant. It
594 /// returns 0 if V is not a pointer, and returns the constant '0' if there are
595 /// no constant offsets applied.
596 ///
597 /// This is very similar to GetPointerBaseWithConstantOffset except it doesn't
598 /// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc.
599 /// folding.
601  bool AllowNonInbounds = false) {
603 
604  Type *IntPtrTy = DL.getIntPtrType(V->getType())->getScalarType();
605  APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());
606 
607  // Even though we don't look through PHI nodes, we could be called on an
608  // instruction in an unreachable block, which may be on a cycle.
609  SmallPtrSet<Value *, 4> Visited;
610  Visited.insert(V);
611  do {
612  if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
613  if ((!AllowNonInbounds && !GEP->isInBounds()) ||
614  !GEP->accumulateConstantOffset(DL, Offset))
615  break;
616  V = GEP->getPointerOperand();
617  } else if (Operator::getOpcode(V) == Instruction::BitCast) {
618  V = cast<Operator>(V)->getOperand(0);
619  } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
620  if (GA->isInterposable())
621  break;
622  V = GA->getAliasee();
623  } else {
624  if (auto CS = CallSite(V))
625  if (Value *RV = CS.getReturnedArgOperand()) {
626  V = RV;
627  continue;
628  }
629  break;
630  }
631  assert(V->getType()->isPtrOrPtrVectorTy() && "Unexpected operand type!");
632  } while (Visited.insert(V).second);
633 
634  Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
635  if (V->getType()->isVectorTy())
637  OffsetIntPtr);
638  return OffsetIntPtr;
639 }
640 
641 /// \brief Compute the constant difference between two pointer values.
642 /// If the difference is not a constant, returns zero.
644  Value *RHS) {
645  Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
646  Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
647 
648  // If LHS and RHS are not related via constant offsets to the same base
649  // value, there is nothing we can do here.
650  if (LHS != RHS)
651  return nullptr;
652 
653  // Otherwise, the difference of LHS - RHS can be computed as:
654  // LHS - RHS
655  // = (LHSOffset + Base) - (RHSOffset + Base)
656  // = LHSOffset - RHSOffset
657  return ConstantExpr::getSub(LHSOffset, RHSOffset);
658 }
659 
660 /// Given operands for a Sub, see if we can fold the result.
661 /// If not, this returns null.
662 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
663  const SimplifyQuery &Q, unsigned MaxRecurse) {
664  if (Constant *C = foldOrCommuteConstant(Instruction::Sub, Op0, Op1, Q))
665  return C;
666 
667  // X - undef -> undef
668  // undef - X -> undef
669  if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
670  return UndefValue::get(Op0->getType());
671 
672  // X - 0 -> X
673  if (match(Op1, m_Zero()))
674  return Op0;
675 
676  // X - X -> 0
677  if (Op0 == Op1)
678  return Constant::getNullValue(Op0->getType());
679 
680  // Is this a negation?
681  if (match(Op0, m_Zero())) {
682  // 0 - X -> 0 if the sub is NUW.
683  if (isNUW)
684  return Op0;
685 
686  KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
687  if (Known.Zero.isMaxSignedValue()) {
688  // Op1 is either 0 or the minimum signed value. If the sub is NSW, then
689  // Op1 must be 0 because negating the minimum signed value is undefined.
690  if (isNSW)
691  return Op0;
692 
693  // 0 - X -> X if X is 0 or the minimum signed value.
694  return Op1;
695  }
696  }
697 
698  // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
699  // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
700  Value *X = nullptr, *Y = nullptr, *Z = Op1;
701  if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
702  // See if "V === Y - Z" simplifies.
703  if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
704  // It does! Now see if "X + V" simplifies.
705  if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
706  // It does, we successfully reassociated!
707  ++NumReassoc;
708  return W;
709  }
710  // See if "V === X - Z" simplifies.
711  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
712  // It does! Now see if "Y + V" simplifies.
713  if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
714  // It does, we successfully reassociated!
715  ++NumReassoc;
716  return W;
717  }
718  }
719 
720  // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
721  // For example, X - (X + 1) -> -1
722  X = Op0;
723  if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
724  // See if "V === X - Y" simplifies.
725  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
726  // It does! Now see if "V - Z" simplifies.
727  if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
728  // It does, we successfully reassociated!
729  ++NumReassoc;
730  return W;
731  }
732  // See if "V === X - Z" simplifies.
733  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
734  // It does! Now see if "V - Y" simplifies.
735  if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
736  // It does, we successfully reassociated!
737  ++NumReassoc;
738  return W;
739  }
740  }
741 
742  // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
743  // For example, X - (X - Y) -> Y.
744  Z = Op0;
745  if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
746  // See if "V === Z - X" simplifies.
747  if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
748  // It does! Now see if "V + Y" simplifies.
749  if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
750  // It does, we successfully reassociated!
751  ++NumReassoc;
752  return W;
753  }
754 
755  // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
756  if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
757  match(Op1, m_Trunc(m_Value(Y))))
758  if (X->getType() == Y->getType())
759  // See if "V === X - Y" simplifies.
760  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
761  // It does! Now see if "trunc V" simplifies.
762  if (Value *W = SimplifyCastInst(Instruction::Trunc, V, Op0->getType(),
763  Q, MaxRecurse - 1))
764  // It does, return the simplified "trunc V".
765  return W;
766 
767  // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
768  if (match(Op0, m_PtrToInt(m_Value(X))) &&
769  match(Op1, m_PtrToInt(m_Value(Y))))
770  if (Constant *Result = computePointerDifference(Q.DL, X, Y))
771  return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
772 
773  // i1 sub -> xor.
774  if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
775  if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
776  return V;
777 
778  // Threading Sub over selects and phi nodes is pointless, so don't bother.
779  // Threading over the select in "A - select(cond, B, C)" means evaluating
780  // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
781  // only if B and C are equal. If B and C are equal then (since we assume
782  // that operands have already been simplified) "select(cond, B, C)" should
783  // have been simplified to the common value of B and C already. Analysing
784  // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
785  // for threading over phi nodes.
786 
787  return nullptr;
788 }
789 
790 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
791  const SimplifyQuery &Q) {
792  return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit);
793 }
794 
795 /// Given operands for a Mul, see if we can fold the result.
796 /// If not, this returns null.
797 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
798  unsigned MaxRecurse) {
799  if (Constant *C = foldOrCommuteConstant(Instruction::Mul, Op0, Op1, Q))
800  return C;
801 
802  // X * undef -> 0
803  if (match(Op1, m_Undef()))
804  return Constant::getNullValue(Op0->getType());
805 
806  // X * 0 -> 0
807  if (match(Op1, m_Zero()))
808  return Op1;
809 
810  // X * 1 -> X
811  if (match(Op1, m_One()))
812  return Op0;
813 
814  // (X / Y) * Y -> X if the division is exact.
815  Value *X = nullptr;
816  if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
817  match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
818  return X;
819 
820  // i1 mul -> and.
821  if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
822  if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
823  return V;
824 
825  // Try some generic simplifications for associative operations.
826  if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
827  MaxRecurse))
828  return V;
829 
830  // Mul distributes over Add. Try some generic simplifications based on this.
831  if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
832  Q, MaxRecurse))
833  return V;
834 
835  // If the operation is with the result of a select instruction, check whether
836  // operating on either branch of the select always yields the same value.
837  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
838  if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
839  MaxRecurse))
840  return V;
841 
842  // If the operation is with the result of a phi instruction, check whether
843  // operating on all incoming values of the phi always yields the same value.
844  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
845  if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
846  MaxRecurse))
847  return V;
848 
849  return nullptr;
850 }
851 
854 }
855 
856 /// Check for common or similar folds of integer division or integer remainder.
857 /// This applies to all 4 opcodes (sdiv/udiv/srem/urem).
858 static Value *simplifyDivRem(Value *Op0, Value *Op1, bool IsDiv) {
859  Type *Ty = Op0->getType();
860 
861  // X / undef -> undef
862  // X % undef -> undef
863  if (match(Op1, m_Undef()))
864  return Op1;
865 
866  // X / 0 -> undef
867  // X % 0 -> undef
868  // We don't need to preserve faults!
869  if (match(Op1, m_Zero()))
870  return UndefValue::get(Ty);
871 
872  // If any element of a constant divisor vector is zero, the whole op is undef.
873  auto *Op1C = dyn_cast<Constant>(Op1);
874  if (Op1C && Ty->isVectorTy()) {
875  unsigned NumElts = Ty->getVectorNumElements();
876  for (unsigned i = 0; i != NumElts; ++i) {
877  Constant *Elt = Op1C->getAggregateElement(i);
878  if (Elt && Elt->isNullValue())
879  return UndefValue::get(Ty);
880  }
881  }
882 
883  // undef / X -> 0
884  // undef % X -> 0
885  if (match(Op0, m_Undef()))
886  return Constant::getNullValue(Ty);
887 
888  // 0 / X -> 0
889  // 0 % X -> 0
890  if (match(Op0, m_Zero()))
891  return Op0;
892 
893  // X / X -> 1
894  // X % X -> 0
895  if (Op0 == Op1)
896  return IsDiv ? ConstantInt::get(Ty, 1) : Constant::getNullValue(Ty);
897 
898  // X / 1 -> X
899  // X % 1 -> 0
900  // If this is a boolean op (single-bit element type), we can't have
901  // division-by-zero or remainder-by-zero, so assume the divisor is 1.
902  if (match(Op1, m_One()) || Ty->isIntOrIntVectorTy(1))
903  return IsDiv ? Op0 : Constant::getNullValue(Ty);
904 
905  return nullptr;
906 }
907 
908 /// Given a predicate and two operands, return true if the comparison is true.
909 /// This is a helper for div/rem simplification where we return some other value
910 /// when we can prove a relationship between the operands.
911 static bool isICmpTrue(ICmpInst::Predicate Pred, Value *LHS, Value *RHS,
912  const SimplifyQuery &Q, unsigned MaxRecurse) {
913  Value *V = SimplifyICmpInst(Pred, LHS, RHS, Q, MaxRecurse);
914  Constant *C = dyn_cast_or_null<Constant>(V);
915  return (C && C->isAllOnesValue());
916 }
917 
918 /// Return true if we can simplify X / Y to 0. Remainder can adapt that answer
919 /// to simplify X % Y to X.
920 static bool isDivZero(Value *X, Value *Y, const SimplifyQuery &Q,
921  unsigned MaxRecurse, bool IsSigned) {
922  // Recursion is always used, so bail out at once if we already hit the limit.
923  if (!MaxRecurse--)
924  return false;
925 
926  if (IsSigned) {
927  // |X| / |Y| --> 0
928  //
929  // We require that 1 operand is a simple constant. That could be extended to
930  // 2 variables if we computed the sign bit for each.
931  //
932  // Make sure that a constant is not the minimum signed value because taking
933  // the abs() of that is undefined.
934  Type *Ty = X->getType();
935  const APInt *C;
936  if (match(X, m_APInt(C)) && !C->isMinSignedValue()) {
937  // Is the variable divisor magnitude always greater than the constant
938  // dividend magnitude?
939  // |Y| > |C| --> Y < -abs(C) or Y > abs(C)
940  Constant *PosDividendC = ConstantInt::get(Ty, C->abs());
941  Constant *NegDividendC = ConstantInt::get(Ty, -C->abs());
942  if (isICmpTrue(CmpInst::ICMP_SLT, Y, NegDividendC, Q, MaxRecurse) ||
943  isICmpTrue(CmpInst::ICMP_SGT, Y, PosDividendC, Q, MaxRecurse))
944  return true;
945  }
946  if (match(Y, m_APInt(C))) {
947  // Special-case: we can't take the abs() of a minimum signed value. If
948  // that's the divisor, then all we have to do is prove that the dividend
949  // is also not the minimum signed value.
950  if (C->isMinSignedValue())
951  return isICmpTrue(CmpInst::ICMP_NE, X, Y, Q, MaxRecurse);
952 
953  // Is the variable dividend magnitude always less than the constant
954  // divisor magnitude?
955  // |X| < |C| --> X > -abs(C) and X < abs(C)
956  Constant *PosDivisorC = ConstantInt::get(Ty, C->abs());
957  Constant *NegDivisorC = ConstantInt::get(Ty, -C->abs());
958  if (isICmpTrue(CmpInst::ICMP_SGT, X, NegDivisorC, Q, MaxRecurse) &&
959  isICmpTrue(CmpInst::ICMP_SLT, X, PosDivisorC, Q, MaxRecurse))
960  return true;
961  }
962  return false;
963  }
964 
965  // IsSigned == false.
966  // Is the dividend unsigned less than the divisor?
967  return isICmpTrue(ICmpInst::ICMP_ULT, X, Y, Q, MaxRecurse);
968 }
969 
970 /// These are simplifications common to SDiv and UDiv.
972  const SimplifyQuery &Q, unsigned MaxRecurse) {
973  if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
974  return C;
975 
976  if (Value *V = simplifyDivRem(Op0, Op1, true))
977  return V;
978 
979  bool IsSigned = Opcode == Instruction::SDiv;
980 
981  // (X * Y) / Y -> X if the multiplication does not overflow.
982  Value *X = nullptr, *Y = nullptr;
983  if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
984  if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
985  OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
986  // If the Mul knows it does not overflow, then we are good to go.
987  if ((IsSigned && Mul->hasNoSignedWrap()) ||
988  (!IsSigned && Mul->hasNoUnsignedWrap()))
989  return X;
990  // If X has the form X = A / Y then X * Y cannot overflow.
991  if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
992  if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
993  return X;
994  }
995 
996  // (X rem Y) / Y -> 0
997  if ((IsSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
998  (!IsSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
999  return Constant::getNullValue(Op0->getType());
1000 
1001  // (X /u C1) /u C2 -> 0 if C1 * C2 overflow
1002  ConstantInt *C1, *C2;
1003  if (!IsSigned && match(Op0, m_UDiv(m_Value(X), m_ConstantInt(C1))) &&
1004  match(Op1, m_ConstantInt(C2))) {
1005  bool Overflow;
1006  (void)C1->getValue().umul_ov(C2->getValue(), Overflow);
1007  if (Overflow)
1008  return Constant::getNullValue(Op0->getType());
1009  }
1010 
1011  // If the operation is with the result of a select instruction, check whether
1012  // operating on either branch of the select always yields the same value.
1013  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1014  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1015  return V;
1016 
1017  // If the operation is with the result of a phi instruction, check whether
1018  // operating on all incoming values of the phi always yields the same value.
1019  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1020  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1021  return V;
1022 
1023  if (isDivZero(Op0, Op1, Q, MaxRecurse, IsSigned))
1024  return Constant::getNullValue(Op0->getType());
1025 
1026  return nullptr;
1027 }
1028 
1029 /// These are simplifications common to SRem and URem.
1031  const SimplifyQuery &Q, unsigned MaxRecurse) {
1032  if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1033  return C;
1034 
1035  if (Value *V = simplifyDivRem(Op0, Op1, false))
1036  return V;
1037 
1038  // (X % Y) % Y -> X % Y
1039  if ((Opcode == Instruction::SRem &&
1040  match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1041  (Opcode == Instruction::URem &&
1042  match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1043  return Op0;
1044 
1045  // If the operation is with the result of a select instruction, check whether
1046  // operating on either branch of the select always yields the same value.
1047  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1048  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1049  return V;
1050 
1051  // If the operation is with the result of a phi instruction, check whether
1052  // operating on all incoming values of the phi always yields the same value.
1053  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1054  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1055  return V;
1056 
1057  // If X / Y == 0, then X % Y == X.
1058  if (isDivZero(Op0, Op1, Q, MaxRecurse, Opcode == Instruction::SRem))
1059  return Op0;
1060 
1061  return nullptr;
1062 }
1063 
1064 /// Given operands for an SDiv, see if we can fold the result.
1065 /// If not, this returns null.
1066 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1067  unsigned MaxRecurse) {
1068  return simplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse);
1069 }
1070 
1073 }
1074 
1075 /// Given operands for a UDiv, see if we can fold the result.
1076 /// If not, this returns null.
1077 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1078  unsigned MaxRecurse) {
1079  return simplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse);
1080 }
1081 
1084 }
1085 
1086 /// Given operands for an SRem, see if we can fold the result.
1087 /// If not, this returns null.
1088 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1089  unsigned MaxRecurse) {
1090  return simplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse);
1091 }
1092 
1095 }
1096 
1097 /// Given operands for a URem, see if we can fold the result.
1098 /// If not, this returns null.
1099 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1100  unsigned MaxRecurse) {
1101  return simplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse);
1102 }
1103 
1106 }
1107 
1108 /// Returns true if a shift by \c Amount always yields undef.
1109 static bool isUndefShift(Value *Amount) {
1110  Constant *C = dyn_cast<Constant>(Amount);
1111  if (!C)
1112  return false;
1113 
1114  // X shift by undef -> undef because it may shift by the bitwidth.
1115  if (isa<UndefValue>(C))
1116  return true;
1117 
1118  // Shifting by the bitwidth or more is undefined.
1119  if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
1120  if (CI->getValue().getLimitedValue() >=
1121  CI->getType()->getScalarSizeInBits())
1122  return true;
1123 
1124  // If all lanes of a vector shift are undefined the whole shift is.
1125  if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) {
1126  for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I)
1128  return false;
1129  return true;
1130  }
1131 
1132  return false;
1133 }
1134 
1135 /// Given operands for an Shl, LShr or AShr, see if we can fold the result.
1136 /// If not, this returns null.
1138  Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse) {
1139  if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1140  return C;
1141 
1142  // 0 shift by X -> 0
1143  if (match(Op0, m_Zero()))
1144  return Op0;
1145 
1146  // X shift by 0 -> X
1147  if (match(Op1, m_Zero()))
1148  return Op0;
1149 
1150  // Fold undefined shifts.
1151  if (isUndefShift(Op1))
1152  return UndefValue::get(Op0->getType());
1153 
1154  // If the operation is with the result of a select instruction, check whether
1155  // operating on either branch of the select always yields the same value.
1156  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1157  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1158  return V;
1159 
1160  // If the operation is with the result of a phi instruction, check whether
1161  // operating on all incoming values of the phi always yields the same value.
1162  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1163  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1164  return V;
1165 
1166  // If any bits in the shift amount make that value greater than or equal to
1167  // the number of bits in the type, the shift is undefined.
1168  KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1169  if (Known.One.getLimitedValue() >= Known.getBitWidth())
1170  return UndefValue::get(Op0->getType());
1171 
1172  // If all valid bits in the shift amount are known zero, the first operand is
1173  // unchanged.
1174  unsigned NumValidShiftBits = Log2_32_Ceil(Known.getBitWidth());
1175  if (Known.countMinTrailingZeros() >= NumValidShiftBits)
1176  return Op0;
1177 
1178  return nullptr;
1179 }
1180 
1181 /// \brief Given operands for an Shl, LShr or AShr, see if we can
1182 /// fold the result. If not, this returns null.
1184  Value *Op1, bool isExact, const SimplifyQuery &Q,
1185  unsigned MaxRecurse) {
1186  if (Value *V = SimplifyShift(Opcode, Op0, Op1, Q, MaxRecurse))
1187  return V;
1188 
1189  // X >> X -> 0
1190  if (Op0 == Op1)
1191  return Constant::getNullValue(Op0->getType());
1192 
1193  // undef >> X -> 0
1194  // undef >> X -> undef (if it's exact)
1195  if (match(Op0, m_Undef()))
1196  return isExact ? Op0 : Constant::getNullValue(Op0->getType());
1197 
1198  // The low bit cannot be shifted out of an exact shift if it is set.
1199  if (isExact) {
1200  KnownBits Op0Known = computeKnownBits(Op0, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT);
1201  if (Op0Known.One[0])
1202  return Op0;
1203  }
1204 
1205  return nullptr;
1206 }
1207 
1208 /// Given operands for an Shl, see if we can fold the result.
1209 /// If not, this returns null.
1210 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1211  const SimplifyQuery &Q, unsigned MaxRecurse) {
1212  if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1213  return V;
1214 
1215  // undef << X -> 0
1216  // undef << X -> undef if (if it's NSW/NUW)
1217  if (match(Op0, m_Undef()))
1218  return isNSW || isNUW ? Op0 : Constant::getNullValue(Op0->getType());
1219 
1220  // (X >> A) << A -> X
1221  Value *X;
1222  if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1223  return X;
1224  return nullptr;
1225 }
1226 
1227 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1228  const SimplifyQuery &Q) {
1229  return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit);
1230 }
1231 
1232 /// Given operands for an LShr, see if we can fold the result.
1233 /// If not, this returns null.
1234 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1235  const SimplifyQuery &Q, unsigned MaxRecurse) {
1236  if (Value *V = SimplifyRightShift(Instruction::LShr, Op0, Op1, isExact, Q,
1237  MaxRecurse))
1238  return V;
1239 
1240  // (X << A) >> A -> X
1241  Value *X;
1242  if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1))))
1243  return X;
1244 
1245  return nullptr;
1246 }
1247 
1248 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1249  const SimplifyQuery &Q) {
1250  return ::SimplifyLShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1251 }
1252 
1253 /// Given operands for an AShr, see if we can fold the result.
1254 /// If not, this returns null.
1255 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1256  const SimplifyQuery &Q, unsigned MaxRecurse) {
1257  if (Value *V = SimplifyRightShift(Instruction::AShr, Op0, Op1, isExact, Q,
1258  MaxRecurse))
1259  return V;
1260 
1261  // all ones >>a X -> all ones
1262  if (match(Op0, m_AllOnes()))
1263  return Op0;
1264 
1265  // (X << A) >> A -> X
1266  Value *X;
1267  if (match(Op0, m_NSWShl(m_Value(X), m_Specific(Op1))))
1268  return X;
1269 
1270  // Arithmetic shifting an all-sign-bit value is a no-op.
1271  unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1272  if (NumSignBits == Op0->getType()->getScalarSizeInBits())
1273  return Op0;
1274 
1275  return nullptr;
1276 }
1277 
1278 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1279  const SimplifyQuery &Q) {
1280  return ::SimplifyAShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1281 }
1282 
1283 /// Commuted variants are assumed to be handled by calling this function again
1284 /// with the parameters swapped.
1286  ICmpInst *UnsignedICmp, bool IsAnd) {
1287  Value *X, *Y;
1288 
1289  ICmpInst::Predicate EqPred;
1290  if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) ||
1291  !ICmpInst::isEquality(EqPred))
1292  return nullptr;
1293 
1294  ICmpInst::Predicate UnsignedPred;
1295  if (match(UnsignedICmp, m_ICmp(UnsignedPred, m_Value(X), m_Specific(Y))) &&
1296  ICmpInst::isUnsigned(UnsignedPred))
1297  ;
1298  else if (match(UnsignedICmp,
1299  m_ICmp(UnsignedPred, m_Value(Y), m_Specific(X))) &&
1300  ICmpInst::isUnsigned(UnsignedPred))
1301  UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred);
1302  else
1303  return nullptr;
1304 
1305  // X < Y && Y != 0 --> X < Y
1306  // X < Y || Y != 0 --> Y != 0
1307  if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE)
1308  return IsAnd ? UnsignedICmp : ZeroICmp;
1309 
1310  // X >= Y || Y != 0 --> true
1311  // X >= Y || Y == 0 --> X >= Y
1312  if (UnsignedPred == ICmpInst::ICMP_UGE && !IsAnd) {
1313  if (EqPred == ICmpInst::ICMP_NE)
1314  return getTrue(UnsignedICmp->getType());
1315  return UnsignedICmp;
1316  }
1317 
1318  // X < Y && Y == 0 --> false
1319  if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
1320  IsAnd)
1321  return getFalse(UnsignedICmp->getType());
1322 
1323  return nullptr;
1324 }
1325 
1326 /// Commuted variants are assumed to be handled by calling this function again
1327 /// with the parameters swapped.
1329  ICmpInst::Predicate Pred0, Pred1;
1330  Value *A ,*B;
1331  if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
1332  !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
1333  return nullptr;
1334 
1335  // We have (icmp Pred0, A, B) & (icmp Pred1, A, B).
1336  // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1337  // can eliminate Op1 from this 'and'.
1338  if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
1339  return Op0;
1340 
1341  // Check for any combination of predicates that are guaranteed to be disjoint.
1342  if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
1343  (Pred0 == ICmpInst::ICMP_EQ && ICmpInst::isFalseWhenEqual(Pred1)) ||
1344  (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT) ||
1345  (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT))
1346  return getFalse(Op0->getType());
1347 
1348  return nullptr;
1349 }
1350 
1351 /// Commuted variants are assumed to be handled by calling this function again
1352 /// with the parameters swapped.
1354  ICmpInst::Predicate Pred0, Pred1;
1355  Value *A ,*B;
1356  if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
1357  !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
1358  return nullptr;
1359 
1360  // We have (icmp Pred0, A, B) | (icmp Pred1, A, B).
1361  // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1362  // can eliminate Op0 from this 'or'.
1363  if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
1364  return Op1;
1365 
1366  // Check for any combination of predicates that cover the entire range of
1367  // possibilities.
1368  if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
1369  (Pred0 == ICmpInst::ICMP_NE && ICmpInst::isTrueWhenEqual(Pred1)) ||
1370  (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGE) ||
1371  (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGE))
1372  return getTrue(Op0->getType());
1373 
1374  return nullptr;
1375 }
1376 
1377 /// Test if a pair of compares with a shared operand and 2 constants has an
1378 /// empty set intersection, full set union, or if one compare is a superset of
1379 /// the other.
1381  bool IsAnd) {
1382  // Look for this pattern: {and/or} (icmp X, C0), (icmp X, C1)).
1383  if (Cmp0->getOperand(0) != Cmp1->getOperand(0))
1384  return nullptr;
1385 
1386  const APInt *C0, *C1;
1387  if (!match(Cmp0->getOperand(1), m_APInt(C0)) ||
1388  !match(Cmp1->getOperand(1), m_APInt(C1)))
1389  return nullptr;
1390 
1391  auto Range0 = ConstantRange::makeExactICmpRegion(Cmp0->getPredicate(), *C0);
1392  auto Range1 = ConstantRange::makeExactICmpRegion(Cmp1->getPredicate(), *C1);
1393 
1394  // For and-of-compares, check if the intersection is empty:
1395  // (icmp X, C0) && (icmp X, C1) --> empty set --> false
1396  if (IsAnd && Range0.intersectWith(Range1).isEmptySet())
1397  return getFalse(Cmp0->getType());
1398 
1399  // For or-of-compares, check if the union is full:
1400  // (icmp X, C0) || (icmp X, C1) --> full set --> true
1401  if (!IsAnd && Range0.unionWith(Range1).isFullSet())
1402  return getTrue(Cmp0->getType());
1403 
1404  // Is one range a superset of the other?
1405  // If this is and-of-compares, take the smaller set:
1406  // (icmp sgt X, 4) && (icmp sgt X, 42) --> icmp sgt X, 42
1407  // If this is or-of-compares, take the larger set:
1408  // (icmp sgt X, 4) || (icmp sgt X, 42) --> icmp sgt X, 4
1409  if (Range0.contains(Range1))
1410  return IsAnd ? Cmp1 : Cmp0;
1411  if (Range1.contains(Range0))
1412  return IsAnd ? Cmp0 : Cmp1;
1413 
1414  return nullptr;
1415 }
1416 
1418  // (icmp (add V, C0), C1) & (icmp V, C0)
1419  ICmpInst::Predicate Pred0, Pred1;
1420  const APInt *C0, *C1;
1421  Value *V;
1422  if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
1423  return nullptr;
1424 
1425  if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
1426  return nullptr;
1427 
1428  auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1429  if (AddInst->getOperand(1) != Op1->getOperand(1))
1430  return nullptr;
1431 
1432  Type *ITy = Op0->getType();
1433  bool isNSW = AddInst->hasNoSignedWrap();
1434  bool isNUW = AddInst->hasNoUnsignedWrap();
1435 
1436  const APInt Delta = *C1 - *C0;
1437  if (C0->isStrictlyPositive()) {
1438  if (Delta == 2) {
1439  if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
1440  return getFalse(ITy);
1441  if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1442  return getFalse(ITy);
1443  }
1444  if (Delta == 1) {
1445  if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
1446  return getFalse(ITy);
1447  if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1448  return getFalse(ITy);
1449  }
1450  }
1451  if (C0->getBoolValue() && isNUW) {
1452  if (Delta == 2)
1453  if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
1454  return getFalse(ITy);
1455  if (Delta == 1)
1456  if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
1457  return getFalse(ITy);
1458  }
1459 
1460  return nullptr;
1461 }
1462 
1464  if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/true))
1465  return X;
1466  if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/true))
1467  return X;
1468 
1469  if (Value *X = simplifyAndOfICmpsWithSameOperands(Op0, Op1))
1470  return X;
1471  if (Value *X = simplifyAndOfICmpsWithSameOperands(Op1, Op0))
1472  return X;
1473 
1474  if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, true))
1475  return X;
1476 
1477  if (Value *X = simplifyAndOfICmpsWithAdd(Op0, Op1))
1478  return X;
1479  if (Value *X = simplifyAndOfICmpsWithAdd(Op1, Op0))
1480  return X;
1481 
1482  return nullptr;
1483 }
1484 
1486  // (icmp (add V, C0), C1) | (icmp V, C0)
1487  ICmpInst::Predicate Pred0, Pred1;
1488  const APInt *C0, *C1;
1489  Value *V;
1490  if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
1491  return nullptr;
1492 
1493  if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
1494  return nullptr;
1495 
1496  auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1497  if (AddInst->getOperand(1) != Op1->getOperand(1))
1498  return nullptr;
1499 
1500  Type *ITy = Op0->getType();
1501  bool isNSW = AddInst->hasNoSignedWrap();
1502  bool isNUW = AddInst->hasNoUnsignedWrap();
1503 
1504  const APInt Delta = *C1 - *C0;
1505  if (C0->isStrictlyPositive()) {
1506  if (Delta == 2) {
1507  if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE)
1508  return getTrue(ITy);
1509  if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1510  return getTrue(ITy);
1511  }
1512  if (Delta == 1) {
1513  if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE)
1514  return getTrue(ITy);
1515  if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1516  return getTrue(ITy);
1517  }
1518  }
1519  if (C0->getBoolValue() && isNUW) {
1520  if (Delta == 2)
1521  if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE)
1522  return getTrue(ITy);
1523  if (Delta == 1)
1524  if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE)
1525  return getTrue(ITy);
1526  }
1527 
1528  return nullptr;
1529 }
1530 
1532  if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/false))
1533  return X;
1534  if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/false))
1535  return X;
1536 
1537  if (Value *X = simplifyOrOfICmpsWithSameOperands(Op0, Op1))
1538  return X;
1539  if (Value *X = simplifyOrOfICmpsWithSameOperands(Op1, Op0))
1540  return X;
1541 
1542  if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, false))
1543  return X;
1544 
1545  if (Value *X = simplifyOrOfICmpsWithAdd(Op0, Op1))
1546  return X;
1547  if (Value *X = simplifyOrOfICmpsWithAdd(Op1, Op0))
1548  return X;
1549 
1550  return nullptr;
1551 }
1552 
1553 static Value *simplifyAndOrOfICmps(Value *Op0, Value *Op1, bool IsAnd) {
1554  // Look through casts of the 'and' operands to find compares.
1555  auto *Cast0 = dyn_cast<CastInst>(Op0);
1556  auto *Cast1 = dyn_cast<CastInst>(Op1);
1557  if (Cast0 && Cast1 && Cast0->getOpcode() == Cast1->getOpcode() &&
1558  Cast0->getSrcTy() == Cast1->getSrcTy()) {
1559  Op0 = Cast0->getOperand(0);
1560  Op1 = Cast1->getOperand(0);
1561  }
1562 
1563  auto *Cmp0 = dyn_cast<ICmpInst>(Op0);
1564  auto *Cmp1 = dyn_cast<ICmpInst>(Op1);
1565  if (!Cmp0 || !Cmp1)
1566  return nullptr;
1567 
1568  Value *V =
1569  IsAnd ? simplifyAndOfICmps(Cmp0, Cmp1) : simplifyOrOfICmps(Cmp0, Cmp1);
1570  if (!V)
1571  return nullptr;
1572  if (!Cast0)
1573  return V;
1574 
1575  // If we looked through casts, we can only handle a constant simplification
1576  // because we are not allowed to create a cast instruction here.
1577  if (auto *C = dyn_cast<Constant>(V))
1578  return ConstantExpr::getCast(Cast0->getOpcode(), C, Cast0->getType());
1579 
1580  return nullptr;
1581 }
1582 
1583 /// Given operands for an And, see if we can fold the result.
1584 /// If not, this returns null.
1585 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1586  unsigned MaxRecurse) {
1587  if (Constant *C = foldOrCommuteConstant(Instruction::And, Op0, Op1, Q))
1588  return C;
1589 
1590  // X & undef -> 0
1591  if (match(Op1, m_Undef()))
1592  return Constant::getNullValue(Op0->getType());
1593 
1594  // X & X = X
1595  if (Op0 == Op1)
1596  return Op0;
1597 
1598  // X & 0 = 0
1599  if (match(Op1, m_Zero()))
1600  return Op1;
1601 
1602  // X & -1 = X
1603  if (match(Op1, m_AllOnes()))
1604  return Op0;
1605 
1606  // A & ~A = ~A & A = 0
1607  if (match(Op0, m_Not(m_Specific(Op1))) ||
1608  match(Op1, m_Not(m_Specific(Op0))))
1609  return Constant::getNullValue(Op0->getType());
1610 
1611  // (A | ?) & A = A
1612  if (match(Op0, m_c_Or(m_Specific(Op1), m_Value())))
1613  return Op1;
1614 
1615  // A & (A | ?) = A
1616  if (match(Op1, m_c_Or(m_Specific(Op0), m_Value())))
1617  return Op0;
1618 
1619  // A mask that only clears known zeros of a shifted value is a no-op.
1620  Value *X;
1621  const APInt *Mask;
1622  const APInt *ShAmt;
1623  if (match(Op1, m_APInt(Mask))) {
1624  // If all bits in the inverted and shifted mask are clear:
1625  // and (shl X, ShAmt), Mask --> shl X, ShAmt
1626  if (match(Op0, m_Shl(m_Value(X), m_APInt(ShAmt))) &&
1627  (~(*Mask)).lshr(*ShAmt).isNullValue())
1628  return Op0;
1629 
1630  // If all bits in the inverted and shifted mask are clear:
1631  // and (lshr X, ShAmt), Mask --> lshr X, ShAmt
1632  if (match(Op0, m_LShr(m_Value(X), m_APInt(ShAmt))) &&
1633  (~(*Mask)).shl(*ShAmt).isNullValue())
1634  return Op0;
1635  }
1636 
1637  // A & (-A) = A if A is a power of two or zero.
1638  if (match(Op0, m_Neg(m_Specific(Op1))) ||
1639  match(Op1, m_Neg(m_Specific(Op0)))) {
1640  if (isKnownToBeAPowerOfTwo(Op0, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1641  Q.DT))
1642  return Op0;
1643  if (isKnownToBeAPowerOfTwo(Op1, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1644  Q.DT))
1645  return Op1;
1646  }
1647 
1648  if (Value *V = simplifyAndOrOfICmps(Op0, Op1, true))
1649  return V;
1650 
1651  // Try some generic simplifications for associative operations.
1652  if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1653  MaxRecurse))
1654  return V;
1655 
1656  // And distributes over Or. Try some generic simplifications based on this.
1657  if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1658  Q, MaxRecurse))
1659  return V;
1660 
1661  // And distributes over Xor. Try some generic simplifications based on this.
1662  if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1663  Q, MaxRecurse))
1664  return V;
1665 
1666  // If the operation is with the result of a select instruction, check whether
1667  // operating on either branch of the select always yields the same value.
1668  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1669  if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1670  MaxRecurse))
1671  return V;
1672 
1673  // If the operation is with the result of a phi instruction, check whether
1674  // operating on all incoming values of the phi always yields the same value.
1675  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1676  if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1677  MaxRecurse))
1678  return V;
1679 
1680  return nullptr;
1681 }
1682 
1685 }
1686 
1687 /// Given operands for an Or, see if we can fold the result.
1688 /// If not, this returns null.
1689 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1690  unsigned MaxRecurse) {
1691  if (Constant *C = foldOrCommuteConstant(Instruction::Or, Op0, Op1, Q))
1692  return C;
1693 
1694  // X | undef -> -1
1695  if (match(Op1, m_Undef()))
1696  return Constant::getAllOnesValue(Op0->getType());
1697 
1698  // X | X = X
1699  if (Op0 == Op1)
1700  return Op0;
1701 
1702  // X | 0 = X
1703  if (match(Op1, m_Zero()))
1704  return Op0;
1705 
1706  // X | -1 = -1
1707  if (match(Op1, m_AllOnes()))
1708  return Op1;
1709 
1710  // A | ~A = ~A | A = -1
1711  if (match(Op0, m_Not(m_Specific(Op1))) ||
1712  match(Op1, m_Not(m_Specific(Op0))))
1713  return Constant::getAllOnesValue(Op0->getType());
1714 
1715  // (A & ?) | A = A
1716  if (match(Op0, m_c_And(m_Specific(Op1), m_Value())))
1717  return Op1;
1718 
1719  // A | (A & ?) = A
1720  if (match(Op1, m_c_And(m_Specific(Op0), m_Value())))
1721  return Op0;
1722 
1723  // ~(A & ?) | A = -1
1724  if (match(Op0, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
1725  return Constant::getAllOnesValue(Op1->getType());
1726 
1727  // A | ~(A & ?) = -1
1728  if (match(Op1, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
1729  return Constant::getAllOnesValue(Op0->getType());
1730 
1731  Value *A, *B;
1732  // (A & ~B) | (A ^ B) -> (A ^ B)
1733  // (~B & A) | (A ^ B) -> (A ^ B)
1734  // (A & ~B) | (B ^ A) -> (B ^ A)
1735  // (~B & A) | (B ^ A) -> (B ^ A)
1736  if (match(Op1, m_Xor(m_Value(A), m_Value(B))) &&
1737  (match(Op0, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
1738  match(Op0, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
1739  return Op1;
1740 
1741  // Commute the 'or' operands.
1742  // (A ^ B) | (A & ~B) -> (A ^ B)
1743  // (A ^ B) | (~B & A) -> (A ^ B)
1744  // (B ^ A) | (A & ~B) -> (B ^ A)
1745  // (B ^ A) | (~B & A) -> (B ^ A)
1746  if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
1747  (match(Op1, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
1748  match(Op1, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
1749  return Op0;
1750 
1751  // (A & B) | (~A ^ B) -> (~A ^ B)
1752  // (B & A) | (~A ^ B) -> (~A ^ B)
1753  // (A & B) | (B ^ ~A) -> (B ^ ~A)
1754  // (B & A) | (B ^ ~A) -> (B ^ ~A)
1755  if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1756  (match(Op1, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
1757  match(Op1, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
1758  return Op1;
1759 
1760  // (~A ^ B) | (A & B) -> (~A ^ B)
1761  // (~A ^ B) | (B & A) -> (~A ^ B)
1762  // (B ^ ~A) | (A & B) -> (B ^ ~A)
1763  // (B ^ ~A) | (B & A) -> (B ^ ~A)
1764  if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1765  (match(Op0, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
1766  match(Op0, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
1767  return Op0;
1768 
1769  if (Value *V = simplifyAndOrOfICmps(Op0, Op1, false))
1770  return V;
1771 
1772  // Try some generic simplifications for associative operations.
1773  if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1774  MaxRecurse))
1775  return V;
1776 
1777  // Or distributes over And. Try some generic simplifications based on this.
1778  if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1779  MaxRecurse))
1780  return V;
1781 
1782  // If the operation is with the result of a select instruction, check whether
1783  // operating on either branch of the select always yields the same value.
1784  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1785  if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1786  MaxRecurse))
1787  return V;
1788 
1789  // (A & C1)|(B & C2)
1790  const APInt *C1, *C2;
1791  if (match(Op0, m_And(m_Value(A), m_APInt(C1))) &&
1792  match(Op1, m_And(m_Value(B), m_APInt(C2)))) {
1793  if (*C1 == ~*C2) {
1794  // (A & C1)|(B & C2)
1795  // If we have: ((V + N) & C1) | (V & C2)
1796  // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
1797  // replace with V+N.
1798  Value *N;
1799  if (C2->isMask() && // C2 == 0+1+
1800  match(A, m_c_Add(m_Specific(B), m_Value(N)))) {
1801  // Add commutes, try both ways.
1802  if (MaskedValueIsZero(N, *C2, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1803  return A;
1804  }
1805  // Or commutes, try both ways.
1806  if (C1->isMask() &&
1807  match(B, m_c_Add(m_Specific(A), m_Value(N)))) {
1808  // Add commutes, try both ways.
1809  if (MaskedValueIsZero(N, *C1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1810  return B;
1811  }
1812  }
1813  }
1814 
1815  // If the operation is with the result of a phi instruction, check whether
1816  // operating on all incoming values of the phi always yields the same value.
1817  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1818  if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1819  return V;
1820 
1821  return nullptr;
1822 }
1823 
1826 }
1827 
1828 /// Given operands for a Xor, see if we can fold the result.
1829 /// If not, this returns null.
1830 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1831  unsigned MaxRecurse) {
1832  if (Constant *C = foldOrCommuteConstant(Instruction::Xor, Op0, Op1, Q))
1833  return C;
1834 
1835  // A ^ undef -> undef
1836  if (match(Op1, m_Undef()))
1837  return Op1;
1838 
1839  // A ^ 0 = A
1840  if (match(Op1, m_Zero()))
1841  return Op0;
1842 
1843  // A ^ A = 0
1844  if (Op0 == Op1)
1845  return Constant::getNullValue(Op0->getType());
1846 
1847  // A ^ ~A = ~A ^ A = -1
1848  if (match(Op0, m_Not(m_Specific(Op1))) ||
1849  match(Op1, m_Not(m_Specific(Op0))))
1850  return Constant::getAllOnesValue(Op0->getType());
1851 
1852  // Try some generic simplifications for associative operations.
1853  if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1854  MaxRecurse))
1855  return V;
1856 
1857  // Threading Xor over selects and phi nodes is pointless, so don't bother.
1858  // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1859  // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1860  // only if B and C are equal. If B and C are equal then (since we assume
1861  // that operands have already been simplified) "select(cond, B, C)" should
1862  // have been simplified to the common value of B and C already. Analysing
1863  // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1864  // for threading over phi nodes.
1865 
1866  return nullptr;
1867 }
1868 
1871 }
1872 
1873 
1875  return CmpInst::makeCmpResultType(Op->getType());
1876 }
1877 
1878 /// Rummage around inside V looking for something equivalent to the comparison
1879 /// "LHS Pred RHS". Return such a value if found, otherwise return null.
1880 /// Helper function for analyzing max/min idioms.
1882  Value *LHS, Value *RHS) {
1884  if (!SI)
1885  return nullptr;
1886  CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1887  if (!Cmp)
1888  return nullptr;
1889  Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1890  if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1891  return Cmp;
1892  if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1893  LHS == CmpRHS && RHS == CmpLHS)
1894  return Cmp;
1895  return nullptr;
1896 }
1897 
1898 // A significant optimization not implemented here is assuming that alloca
1899 // addresses are not equal to incoming argument values. They don't *alias*,
1900 // as we say, but that doesn't mean they aren't equal, so we take a
1901 // conservative approach.
1902 //
1903 // This is inspired in part by C++11 5.10p1:
1904 // "Two pointers of the same type compare equal if and only if they are both
1905 // null, both point to the same function, or both represent the same
1906 // address."
1907 //
1908 // This is pretty permissive.
1909 //
1910 // It's also partly due to C11 6.5.9p6:
1911 // "Two pointers compare equal if and only if both are null pointers, both are
1912 // pointers to the same object (including a pointer to an object and a
1913 // subobject at its beginning) or function, both are pointers to one past the
1914 // last element of the same array object, or one is a pointer to one past the
1915 // end of one array object and the other is a pointer to the start of a
1916 // different array object that happens to immediately follow the first array
1917 // object in the address space.)
1918 //
1919 // C11's version is more restrictive, however there's no reason why an argument
1920 // couldn't be a one-past-the-end value for a stack object in the caller and be
1921 // equal to the beginning of a stack object in the callee.
1922 //
1923 // If the C and C++ standards are ever made sufficiently restrictive in this
1924 // area, it may be possible to update LLVM's semantics accordingly and reinstate
1925 // this optimization.
1926 static Constant *
1928  const DominatorTree *DT, CmpInst::Predicate Pred,
1929  AssumptionCache *AC, const Instruction *CxtI,
1930  Value *LHS, Value *RHS) {
1931  // First, skip past any trivial no-ops.
1932  LHS = LHS->stripPointerCasts();
1933  RHS = RHS->stripPointerCasts();
1934 
1935  // A non-null pointer is not equal to a null pointer.
1936  if (llvm::isKnownNonZero(LHS, DL) && isa<ConstantPointerNull>(RHS) &&
1937  (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
1938  return ConstantInt::get(GetCompareTy(LHS),
1939  !CmpInst::isTrueWhenEqual(Pred));
1940 
1941  // We can only fold certain predicates on pointer comparisons.
1942  switch (Pred) {
1943  default:
1944  return nullptr;
1945 
1946  // Equality comaprisons are easy to fold.
1947  case CmpInst::ICMP_EQ:
1948  case CmpInst::ICMP_NE:
1949  break;
1950 
1951  // We can only handle unsigned relational comparisons because 'inbounds' on
1952  // a GEP only protects against unsigned wrapping.
1953  case CmpInst::ICMP_UGT:
1954  case CmpInst::ICMP_UGE:
1955  case CmpInst::ICMP_ULT:
1956  case CmpInst::ICMP_ULE:
1957  // However, we have to switch them to their signed variants to handle
1958  // negative indices from the base pointer.
1959  Pred = ICmpInst::getSignedPredicate(Pred);
1960  break;
1961  }
1962 
1963  // Strip off any constant offsets so that we can reason about them.
1964  // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
1965  // here and compare base addresses like AliasAnalysis does, however there are
1966  // numerous hazards. AliasAnalysis and its utilities rely on special rules
1967  // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
1968  // doesn't need to guarantee pointer inequality when it says NoAlias.
1969  Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
1970  Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
1971 
1972  // If LHS and RHS are related via constant offsets to the same base
1973  // value, we can replace it with an icmp which just compares the offsets.
1974  if (LHS == RHS)
1975  return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
1976 
1977  // Various optimizations for (in)equality comparisons.
1978  if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
1979  // Different non-empty allocations that exist at the same time have
1980  // different addresses (if the program can tell). Global variables always
1981  // exist, so they always exist during the lifetime of each other and all
1982  // allocas. Two different allocas usually have different addresses...
1983  //
1984  // However, if there's an @llvm.stackrestore dynamically in between two
1985  // allocas, they may have the same address. It's tempting to reduce the
1986  // scope of the problem by only looking at *static* allocas here. That would
1987  // cover the majority of allocas while significantly reducing the likelihood
1988  // of having an @llvm.stackrestore pop up in the middle. However, it's not
1989  // actually impossible for an @llvm.stackrestore to pop up in the middle of
1990  // an entry block. Also, if we have a block that's not attached to a
1991  // function, we can't tell if it's "static" under the current definition.
1992  // Theoretically, this problem could be fixed by creating a new kind of
1993  // instruction kind specifically for static allocas. Such a new instruction
1994  // could be required to be at the top of the entry block, thus preventing it
1995  // from being subject to a @llvm.stackrestore. Instcombine could even
1996  // convert regular allocas into these special allocas. It'd be nifty.
1997  // However, until then, this problem remains open.
1998  //
1999  // So, we'll assume that two non-empty allocas have different addresses
2000  // for now.
2001  //
2002  // With all that, if the offsets are within the bounds of their allocations
2003  // (and not one-past-the-end! so we can't use inbounds!), and their
2004  // allocations aren't the same, the pointers are not equal.
2005  //
2006  // Note that it's not necessary to check for LHS being a global variable
2007  // address, due to canonicalization and constant folding.
2008  if (isa<AllocaInst>(LHS) &&
2009  (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
2010  ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
2011  ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
2012  uint64_t LHSSize, RHSSize;
2013  if (LHSOffsetCI && RHSOffsetCI &&
2014  getObjectSize(LHS, LHSSize, DL, TLI) &&
2015  getObjectSize(RHS, RHSSize, DL, TLI)) {
2016  const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
2017  const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
2018  if (!LHSOffsetValue.isNegative() &&
2019  !RHSOffsetValue.isNegative() &&
2020  LHSOffsetValue.ult(LHSSize) &&
2021  RHSOffsetValue.ult(RHSSize)) {
2022  return ConstantInt::get(GetCompareTy(LHS),
2023  !CmpInst::isTrueWhenEqual(Pred));
2024  }
2025  }
2026 
2027  // Repeat the above check but this time without depending on DataLayout
2028  // or being able to compute a precise size.
2029  if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
2030  !cast<PointerType>(RHS->getType())->isEmptyTy() &&
2031  LHSOffset->isNullValue() &&
2032  RHSOffset->isNullValue())
2033  return ConstantInt::get(GetCompareTy(LHS),
2034  !CmpInst::isTrueWhenEqual(Pred));
2035  }
2036 
2037  // Even if an non-inbounds GEP occurs along the path we can still optimize
2038  // equality comparisons concerning the result. We avoid walking the whole
2039  // chain again by starting where the last calls to
2040  // stripAndComputeConstantOffsets left off and accumulate the offsets.
2041  Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
2042  Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
2043  if (LHS == RHS)
2044  return ConstantExpr::getICmp(Pred,
2045  ConstantExpr::getAdd(LHSOffset, LHSNoBound),
2046  ConstantExpr::getAdd(RHSOffset, RHSNoBound));
2047 
2048  // If one side of the equality comparison must come from a noalias call
2049  // (meaning a system memory allocation function), and the other side must
2050  // come from a pointer that cannot overlap with dynamically-allocated
2051  // memory within the lifetime of the current function (allocas, byval
2052  // arguments, globals), then determine the comparison result here.
2053  SmallVector<Value *, 8> LHSUObjs, RHSUObjs;
2054  GetUnderlyingObjects(LHS, LHSUObjs, DL);
2055  GetUnderlyingObjects(RHS, RHSUObjs, DL);
2056 
2057  // Is the set of underlying objects all noalias calls?
2058  auto IsNAC = [](ArrayRef<Value *> Objects) {
2059  return all_of(Objects, isNoAliasCall);
2060  };
2061 
2062  // Is the set of underlying objects all things which must be disjoint from
2063  // noalias calls. For allocas, we consider only static ones (dynamic
2064  // allocas might be transformed into calls to malloc not simultaneously
2065  // live with the compared-to allocation). For globals, we exclude symbols
2066  // that might be resolve lazily to symbols in another dynamically-loaded
2067  // library (and, thus, could be malloc'ed by the implementation).
2068  auto IsAllocDisjoint = [](ArrayRef<Value *> Objects) {
2069  return all_of(Objects, [](Value *V) {
2070  if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
2071  return AI->getParent() && AI->getFunction() && AI->isStaticAlloca();
2072  if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
2073  return (GV->hasLocalLinkage() || GV->hasHiddenVisibility() ||
2074  GV->hasProtectedVisibility() || GV->hasGlobalUnnamedAddr()) &&
2075  !GV->isThreadLocal();
2076  if (const Argument *A = dyn_cast<Argument>(V))
2077  return A->hasByValAttr();
2078  return false;
2079  });
2080  };
2081 
2082  if ((IsNAC(LHSUObjs) && IsAllocDisjoint(RHSUObjs)) ||
2083  (IsNAC(RHSUObjs) && IsAllocDisjoint(LHSUObjs)))
2084  return ConstantInt::get(GetCompareTy(LHS),
2085  !CmpInst::isTrueWhenEqual(Pred));
2086 
2087  // Fold comparisons for non-escaping pointer even if the allocation call
2088  // cannot be elided. We cannot fold malloc comparison to null. Also, the
2089  // dynamic allocation call could be either of the operands.
2090  Value *MI = nullptr;
2091  if (isAllocLikeFn(LHS, TLI) &&
2092  llvm::isKnownNonZero(RHS, DL, 0, nullptr, CxtI, DT))
2093  MI = LHS;
2094  else if (isAllocLikeFn(RHS, TLI) &&
2095  llvm::isKnownNonZero(LHS, DL, 0, nullptr, CxtI, DT))
2096  MI = RHS;
2097  // FIXME: We should also fold the compare when the pointer escapes, but the
2098  // compare dominates the pointer escape
2099  if (MI && !PointerMayBeCaptured(MI, true, true))
2100  return ConstantInt::get(GetCompareTy(LHS),
2102  }
2103 
2104  // Otherwise, fail.
2105  return nullptr;
2106 }
2107 
2108 /// Fold an icmp when its operands have i1 scalar type.
2110  Value *RHS, const SimplifyQuery &Q) {
2111  Type *ITy = GetCompareTy(LHS); // The return type.
2112  Type *OpTy = LHS->getType(); // The operand type.
2113  if (!OpTy->isIntOrIntVectorTy(1))
2114  return nullptr;
2115 
2116  // A boolean compared to true/false can be simplified in 14 out of the 20
2117  // (10 predicates * 2 constants) possible combinations. Cases not handled here
2118  // require a 'not' of the LHS, so those must be transformed in InstCombine.
2119  if (match(RHS, m_Zero())) {
2120  switch (Pred) {
2121  case CmpInst::ICMP_NE: // X != 0 -> X
2122  case CmpInst::ICMP_UGT: // X >u 0 -> X
2123  case CmpInst::ICMP_SLT: // X <s 0 -> X
2124  return LHS;
2125 
2126  case CmpInst::ICMP_ULT: // X <u 0 -> false
2127  case CmpInst::ICMP_SGT: // X >s 0 -> false
2128  return getFalse(ITy);
2129 
2130  case CmpInst::ICMP_UGE: // X >=u 0 -> true
2131  case CmpInst::ICMP_SLE: // X <=s 0 -> true
2132  return getTrue(ITy);
2133 
2134  default: break;
2135  }
2136  } else if (match(RHS, m_One())) {
2137  switch (Pred) {
2138  case CmpInst::ICMP_EQ: // X == 1 -> X
2139  case CmpInst::ICMP_UGE: // X >=u 1 -> X
2140  case CmpInst::ICMP_SLE: // X <=s -1 -> X
2141  return LHS;
2142 
2143  case CmpInst::ICMP_UGT: // X >u 1 -> false
2144  case CmpInst::ICMP_SLT: // X <s -1 -> false
2145  return getFalse(ITy);
2146 
2147  case CmpInst::ICMP_ULE: // X <=u 1 -> true
2148  case CmpInst::ICMP_SGE: // X >=s -1 -> true
2149  return getTrue(ITy);
2150 
2151  default: break;
2152  }
2153  }
2154 
2155  switch (Pred) {
2156  default:
2157  break;
2158  case ICmpInst::ICMP_UGE:
2159  if (isImpliedCondition(RHS, LHS, Q.DL).getValueOr(false))
2160  return getTrue(ITy);
2161  break;
2162  case ICmpInst::ICMP_SGE:
2163  /// For signed comparison, the values for an i1 are 0 and -1
2164  /// respectively. This maps into a truth table of:
2165  /// LHS | RHS | LHS >=s RHS | LHS implies RHS
2166  /// 0 | 0 | 1 (0 >= 0) | 1
2167  /// 0 | 1 | 1 (0 >= -1) | 1
2168  /// 1 | 0 | 0 (-1 >= 0) | 0
2169  /// 1 | 1 | 1 (-1 >= -1) | 1
2170  if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2171  return getTrue(ITy);
2172  break;
2173  case ICmpInst::ICMP_ULE:
2174  if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2175  return getTrue(ITy);
2176  break;
2177  }
2178 
2179  return nullptr;
2180 }
2181 
2182 /// Try hard to fold icmp with zero RHS because this is a common case.
2184  Value *RHS, const SimplifyQuery &Q) {
2185  if (!match(RHS, m_Zero()))
2186  return nullptr;
2187 
2188  Type *ITy = GetCompareTy(LHS); // The return type.
2189  switch (Pred) {
2190  default:
2191  llvm_unreachable("Unknown ICmp predicate!");
2192  case ICmpInst::ICMP_ULT:
2193  return getFalse(ITy);
2194  case ICmpInst::ICMP_UGE:
2195  return getTrue(ITy);
2196  case ICmpInst::ICMP_EQ:
2197  case ICmpInst::ICMP_ULE:
2198  if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2199  return getFalse(ITy);
2200  break;
2201  case ICmpInst::ICMP_NE:
2202  case ICmpInst::ICMP_UGT:
2203  if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2204  return getTrue(ITy);
2205  break;
2206  case ICmpInst::ICMP_SLT: {
2207  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2208  if (LHSKnown.isNegative())
2209  return getTrue(ITy);
2210  if (LHSKnown.isNonNegative())
2211  return getFalse(ITy);
2212  break;
2213  }
2214  case ICmpInst::ICMP_SLE: {
2215  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2216  if (LHSKnown.isNegative())
2217  return getTrue(ITy);
2218  if (LHSKnown.isNonNegative() &&
2219  isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2220  return getFalse(ITy);
2221  break;
2222  }
2223  case ICmpInst::ICMP_SGE: {
2224  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2225  if (LHSKnown.isNegative())
2226  return getFalse(ITy);
2227  if (LHSKnown.isNonNegative())
2228  return getTrue(ITy);
2229  break;
2230  }
2231  case ICmpInst::ICMP_SGT: {
2232  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2233  if (LHSKnown.isNegative())
2234  return getFalse(ITy);
2235  if (LHSKnown.isNonNegative() &&
2236  isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2237  return getTrue(ITy);
2238  break;
2239  }
2240  }
2241 
2242  return nullptr;
2243 }
2244 
2245 /// Many binary operators with a constant operand have an easy-to-compute
2246 /// range of outputs. This can be used to fold a comparison to always true or
2247 /// always false.
2248 static void setLimitsForBinOp(BinaryOperator &BO, APInt &Lower, APInt &Upper) {
2249  unsigned Width = Lower.getBitWidth();
2250  const APInt *C;
2251  switch (BO.getOpcode()) {
2252  case Instruction::Add:
2253  if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
2254  // FIXME: If we have both nuw and nsw, we should reduce the range further.
2255  if (BO.hasNoUnsignedWrap()) {
2256  // 'add nuw x, C' produces [C, UINT_MAX].
2257  Lower = *C;
2258  } else if (BO.hasNoSignedWrap()) {
2259  if (C->isNegative()) {
2260  // 'add nsw x, -C' produces [SINT_MIN, SINT_MAX - C].
2261  Lower = APInt::getSignedMinValue(Width);
2262  Upper = APInt::getSignedMaxValue(Width) + *C + 1;
2263  } else {
2264  // 'add nsw x, +C' produces [SINT_MIN + C, SINT_MAX].
2265  Lower = APInt::getSignedMinValue(Width) + *C;
2266  Upper = APInt::getSignedMaxValue(Width) + 1;
2267  }
2268  }
2269  }
2270  break;
2271 
2272  case Instruction::And:
2273  if (match(BO.getOperand(1), m_APInt(C)))
2274  // 'and x, C' produces [0, C].
2275  Upper = *C + 1;
2276  break;
2277 
2278  case Instruction::Or:
2279  if (match(BO.getOperand(1), m_APInt(C)))
2280  // 'or x, C' produces [C, UINT_MAX].
2281  Lower = *C;
2282  break;
2283 
2284  case Instruction::AShr:
2285  if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
2286  // 'ashr x, C' produces [INT_MIN >> C, INT_MAX >> C].
2287  Lower = APInt::getSignedMinValue(Width).ashr(*C);
2288  Upper = APInt::getSignedMaxValue(Width).ashr(*C) + 1;
2289  } else if (match(BO.getOperand(0), m_APInt(C))) {
2290  unsigned ShiftAmount = Width - 1;
2291  if (!C->isNullValue() && BO.isExact())
2292  ShiftAmount = C->countTrailingZeros();
2293  if (C->isNegative()) {
2294  // 'ashr C, x' produces [C, C >> (Width-1)]
2295  Lower = *C;
2296  Upper = C->ashr(ShiftAmount) + 1;
2297  } else {
2298  // 'ashr C, x' produces [C >> (Width-1), C]
2299  Lower = C->ashr(ShiftAmount);
2300  Upper = *C + 1;
2301  }
2302  }
2303  break;
2304 
2305  case Instruction::LShr:
2306  if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
2307  // 'lshr x, C' produces [0, UINT_MAX >> C].
2308  Upper = APInt::getAllOnesValue(Width).lshr(*C) + 1;
2309  } else if (match(BO.getOperand(0), m_APInt(C))) {
2310  // 'lshr C, x' produces [C >> (Width-1), C].
2311  unsigned ShiftAmount = Width - 1;
2312  if (!C->isNullValue() && BO.isExact())
2313  ShiftAmount = C->countTrailingZeros();
2314  Lower = C->lshr(ShiftAmount);
2315  Upper = *C + 1;
2316  }
2317  break;
2318 
2319  case Instruction::Shl:
2320  if (match(BO.getOperand(0), m_APInt(C))) {
2321  if (BO.hasNoUnsignedWrap()) {
2322  // 'shl nuw C, x' produces [C, C << CLZ(C)]
2323  Lower = *C;
2324  Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
2325  } else if (BO.hasNoSignedWrap()) { // TODO: What if both nuw+nsw?
2326  if (C->isNegative()) {
2327  // 'shl nsw C, x' produces [C << CLO(C)-1, C]
2328  unsigned ShiftAmount = C->countLeadingOnes() - 1;
2329  Lower = C->shl(ShiftAmount);
2330  Upper = *C + 1;
2331  } else {
2332  // 'shl nsw C, x' produces [C, C << CLZ(C)-1]
2333  unsigned ShiftAmount = C->countLeadingZeros() - 1;
2334  Lower = *C;
2335  Upper = C->shl(ShiftAmount) + 1;
2336  }
2337  }
2338  }
2339  break;
2340 
2341  case Instruction::SDiv:
2342  if (match(BO.getOperand(1), m_APInt(C))) {
2343  APInt IntMin = APInt::getSignedMinValue(Width);
2344  APInt IntMax = APInt::getSignedMaxValue(Width);
2345  if (C->isAllOnesValue()) {
2346  // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
2347  // where C != -1 and C != 0 and C != 1
2348  Lower = IntMin + 1;
2349  Upper = IntMax + 1;
2350  } else if (C->countLeadingZeros() < Width - 1) {
2351  // 'sdiv x, C' produces [INT_MIN / C, INT_MAX / C]
2352  // where C != -1 and C != 0 and C != 1
2353  Lower = IntMin.sdiv(*C);
2354  Upper = IntMax.sdiv(*C);
2355  if (Lower.sgt(Upper))
2356  std::swap(Lower, Upper);
2357  Upper = Upper + 1;
2358  assert(Upper != Lower && "Upper part of range has wrapped!");
2359  }
2360  } else if (match(BO.getOperand(0), m_APInt(C))) {
2361  if (C->isMinSignedValue()) {
2362  // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
2363  Lower = *C;
2364  Upper = Lower.lshr(1) + 1;
2365  } else {
2366  // 'sdiv C, x' produces [-|C|, |C|].
2367  Upper = C->abs() + 1;
2368  Lower = (-Upper) + 1;
2369  }
2370  }
2371  break;
2372 
2373  case Instruction::UDiv:
2374  if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
2375  // 'udiv x, C' produces [0, UINT_MAX / C].
2376  Upper = APInt::getMaxValue(Width).udiv(*C) + 1;
2377  } else if (match(BO.getOperand(0), m_APInt(C))) {
2378  // 'udiv C, x' produces [0, C].
2379  Upper = *C + 1;
2380  }
2381  break;
2382 
2383  case Instruction::SRem:
2384  if (match(BO.getOperand(1), m_APInt(C))) {
2385  // 'srem x, C' produces (-|C|, |C|).
2386  Upper = C->abs();
2387  Lower = (-Upper) + 1;
2388  }
2389  break;
2390 
2391  case Instruction::URem:
2392  if (match(BO.getOperand(1), m_APInt(C)))
2393  // 'urem x, C' produces [0, C).
2394  Upper = *C;
2395  break;
2396 
2397  default:
2398  break;
2399  }
2400 }
2401 
2403  Value *RHS) {
2404  const APInt *C;
2405  if (!match(RHS, m_APInt(C)))
2406  return nullptr;
2407 
2408  // Rule out tautological comparisons (eg., ult 0 or uge 0).
2410  if (RHS_CR.isEmptySet())
2411  return ConstantInt::getFalse(GetCompareTy(RHS));
2412  if (RHS_CR.isFullSet())
2413  return ConstantInt::getTrue(GetCompareTy(RHS));
2414 
2415  // Find the range of possible values for binary operators.
2416  unsigned Width = C->getBitWidth();
2417  APInt Lower = APInt(Width, 0);
2418  APInt Upper = APInt(Width, 0);
2419  if (auto *BO = dyn_cast<BinaryOperator>(LHS))
2420  setLimitsForBinOp(*BO, Lower, Upper);
2421 
2422  ConstantRange LHS_CR =
2423  Lower != Upper ? ConstantRange(Lower, Upper) : ConstantRange(Width, true);
2424 
2425  if (auto *I = dyn_cast<Instruction>(LHS))
2426  if (auto *Ranges = I->getMetadata(LLVMContext::MD_range))
2427  LHS_CR = LHS_CR.intersectWith(getConstantRangeFromMetadata(*Ranges));
2428 
2429  if (!LHS_CR.isFullSet()) {
2430  if (RHS_CR.contains(LHS_CR))
2431  return ConstantInt::getTrue(GetCompareTy(RHS));
2432  if (RHS_CR.inverse().contains(LHS_CR))
2433  return ConstantInt::getFalse(GetCompareTy(RHS));
2434  }
2435 
2436  return nullptr;
2437 }
2438 
2439 /// TODO: A large part of this logic is duplicated in InstCombine's
2440 /// foldICmpBinOp(). We should be able to share that and avoid the code
2441 /// duplication.
2443  Value *RHS, const SimplifyQuery &Q,
2444  unsigned MaxRecurse) {
2445  Type *ITy = GetCompareTy(LHS); // The return type.
2446 
2447  BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2448  BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2449  if (MaxRecurse && (LBO || RBO)) {
2450  // Analyze the case when either LHS or RHS is an add instruction.
2451  Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
2452  // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2453  bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2454  if (LBO && LBO->getOpcode() == Instruction::Add) {
2455  A = LBO->getOperand(0);
2456  B = LBO->getOperand(1);
2457  NoLHSWrapProblem =
2458  ICmpInst::isEquality(Pred) ||
2459  (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2460  (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2461  }
2462  if (RBO && RBO->getOpcode() == Instruction::Add) {
2463  C = RBO->getOperand(0);
2464  D = RBO->getOperand(1);
2465  NoRHSWrapProblem =
2466  ICmpInst::isEquality(Pred) ||
2467  (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2468  (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2469  }
2470 
2471  // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2472  if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2473  if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2474  Constant::getNullValue(RHS->getType()), Q,
2475  MaxRecurse - 1))
2476  return V;
2477 
2478  // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2479  if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2480  if (Value *V =
2482  C == LHS ? D : C, Q, MaxRecurse - 1))
2483  return V;
2484 
2485  // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2486  if (A && C && (A == C || A == D || B == C || B == D) && NoLHSWrapProblem &&
2487  NoRHSWrapProblem) {
2488  // Determine Y and Z in the form icmp (X+Y), (X+Z).
2489  Value *Y, *Z;
2490  if (A == C) {
2491  // C + B == C + D -> B == D
2492  Y = B;
2493  Z = D;
2494  } else if (A == D) {
2495  // D + B == C + D -> B == C
2496  Y = B;
2497  Z = C;
2498  } else if (B == C) {
2499  // A + C == C + D -> A == D
2500  Y = A;
2501  Z = D;
2502  } else {
2503  assert(B == D);
2504  // A + D == C + D -> A == C
2505  Y = A;
2506  Z = C;
2507  }
2508  if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse - 1))
2509  return V;
2510  }
2511  }
2512 
2513  {
2514  Value *Y = nullptr;
2515  // icmp pred (or X, Y), X
2516  if (LBO && match(LBO, m_c_Or(m_Value(Y), m_Specific(RHS)))) {
2517  if (Pred == ICmpInst::ICMP_ULT)
2518  return getFalse(ITy);
2519  if (Pred == ICmpInst::ICMP_UGE)
2520  return getTrue(ITy);
2521 
2522  if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SGE) {
2523  KnownBits RHSKnown = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2524  KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2525  if (RHSKnown.isNonNegative() && YKnown.isNegative())
2526  return Pred == ICmpInst::ICMP_SLT ? getTrue(ITy) : getFalse(ITy);
2527  if (RHSKnown.isNegative() || YKnown.isNonNegative())
2528  return Pred == ICmpInst::ICMP_SLT ? getFalse(ITy) : getTrue(ITy);
2529  }
2530  }
2531  // icmp pred X, (or X, Y)
2532  if (RBO && match(RBO, m_c_Or(m_Value(Y), m_Specific(LHS)))) {
2533  if (Pred == ICmpInst::ICMP_ULE)
2534  return getTrue(ITy);
2535  if (Pred == ICmpInst::ICMP_UGT)
2536  return getFalse(ITy);
2537 
2538  if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SLE) {
2539  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2540  KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2541  if (LHSKnown.isNonNegative() && YKnown.isNegative())
2542  return Pred == ICmpInst::ICMP_SGT ? getTrue(ITy) : getFalse(ITy);
2543  if (LHSKnown.isNegative() || YKnown.isNonNegative())
2544  return Pred == ICmpInst::ICMP_SGT ? getFalse(ITy) : getTrue(ITy);
2545  }
2546  }
2547  }
2548 
2549  // icmp pred (and X, Y), X
2550  if (LBO && match(LBO, m_c_And(m_Value(), m_Specific(RHS)))) {
2551  if (Pred == ICmpInst::ICMP_UGT)
2552  return getFalse(ITy);
2553  if (Pred == ICmpInst::ICMP_ULE)
2554  return getTrue(ITy);
2555  }
2556  // icmp pred X, (and X, Y)
2557  if (RBO && match(RBO, m_c_And(m_Value(), m_Specific(LHS)))) {
2558  if (Pred == ICmpInst::ICMP_UGE)
2559  return getTrue(ITy);
2560  if (Pred == ICmpInst::ICMP_ULT)
2561  return getFalse(ITy);
2562  }
2563 
2564  // 0 - (zext X) pred C
2565  if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
2566  if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
2567  if (RHSC->getValue().isStrictlyPositive()) {
2568  if (Pred == ICmpInst::ICMP_SLT)
2569  return ConstantInt::getTrue(RHSC->getContext());
2570  if (Pred == ICmpInst::ICMP_SGE)
2571  return ConstantInt::getFalse(RHSC->getContext());
2572  if (Pred == ICmpInst::ICMP_EQ)
2573  return ConstantInt::getFalse(RHSC->getContext());
2574  if (Pred == ICmpInst::ICMP_NE)
2575  return ConstantInt::getTrue(RHSC->getContext());
2576  }
2577  if (RHSC->getValue().isNonNegative()) {
2578  if (Pred == ICmpInst::ICMP_SLE)
2579  return ConstantInt::getTrue(RHSC->getContext());
2580  if (Pred == ICmpInst::ICMP_SGT)
2581  return ConstantInt::getFalse(RHSC->getContext());
2582  }
2583  }
2584  }
2585 
2586  // icmp pred (urem X, Y), Y
2587  if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2588  switch (Pred) {
2589  default:
2590  break;
2591  case ICmpInst::ICMP_SGT:
2592  case ICmpInst::ICMP_SGE: {
2593  KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2594  if (!Known.isNonNegative())
2595  break;
2597  }
2598  case ICmpInst::ICMP_EQ:
2599  case ICmpInst::ICMP_UGT:
2600  case ICmpInst::ICMP_UGE:
2601  return getFalse(ITy);
2602  case ICmpInst::ICMP_SLT:
2603  case ICmpInst::ICMP_SLE: {
2604  KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2605  if (!Known.isNonNegative())
2606  break;
2608  }
2609  case ICmpInst::ICMP_NE:
2610  case ICmpInst::ICMP_ULT:
2611  case ICmpInst::ICMP_ULE:
2612  return getTrue(ITy);
2613  }
2614  }
2615 
2616  // icmp pred X, (urem Y, X)
2617  if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2618  switch (Pred) {
2619  default:
2620  break;
2621  case ICmpInst::ICMP_SGT:
2622  case ICmpInst::ICMP_SGE: {
2623  KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2624  if (!Known.isNonNegative())
2625  break;
2627  }
2628  case ICmpInst::ICMP_NE:
2629  case ICmpInst::ICMP_UGT:
2630  case ICmpInst::ICMP_UGE:
2631  return getTrue(ITy);
2632  case ICmpInst::ICMP_SLT:
2633  case ICmpInst::ICMP_SLE: {
2634  KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2635  if (!Known.isNonNegative())
2636  break;
2638  }
2639  case ICmpInst::ICMP_EQ:
2640  case ICmpInst::ICMP_ULT:
2641  case ICmpInst::ICMP_ULE:
2642  return getFalse(ITy);
2643  }
2644  }
2645 
2646  // x >> y <=u x
2647  // x udiv y <=u x.
2648  if (LBO && (match(LBO, m_LShr(m_Specific(RHS), m_Value())) ||
2649  match(LBO, m_UDiv(m_Specific(RHS), m_Value())))) {
2650  // icmp pred (X op Y), X
2651  if (Pred == ICmpInst::ICMP_UGT)
2652  return getFalse(ITy);
2653  if (Pred == ICmpInst::ICMP_ULE)
2654  return getTrue(ITy);
2655  }
2656 
2657  // x >=u x >> y
2658  // x >=u x udiv y.
2659  if (RBO && (match(RBO, m_LShr(m_Specific(LHS), m_Value())) ||
2660  match(RBO, m_UDiv(m_Specific(LHS), m_Value())))) {
2661  // icmp pred X, (X op Y)
2662  if (Pred == ICmpInst::ICMP_ULT)
2663  return getFalse(ITy);
2664  if (Pred == ICmpInst::ICMP_UGE)
2665  return getTrue(ITy);
2666  }
2667 
2668  // handle:
2669  // CI2 << X == CI
2670  // CI2 << X != CI
2671  //
2672  // where CI2 is a power of 2 and CI isn't
2673  if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
2674  const APInt *CI2Val, *CIVal = &CI->getValue();
2675  if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
2676  CI2Val->isPowerOf2()) {
2677  if (!CIVal->isPowerOf2()) {
2678  // CI2 << X can equal zero in some circumstances,
2679  // this simplification is unsafe if CI is zero.
2680  //
2681  // We know it is safe if:
2682  // - The shift is nsw, we can't shift out the one bit.
2683  // - The shift is nuw, we can't shift out the one bit.
2684  // - CI2 is one
2685  // - CI isn't zero
2686  if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
2687  CI2Val->isOneValue() || !CI->isZero()) {
2688  if (Pred == ICmpInst::ICMP_EQ)
2689  return ConstantInt::getFalse(RHS->getContext());
2690  if (Pred == ICmpInst::ICMP_NE)
2691  return ConstantInt::getTrue(RHS->getContext());
2692  }
2693  }
2694  if (CIVal->isSignMask() && CI2Val->isOneValue()) {
2695  if (Pred == ICmpInst::ICMP_UGT)
2696  return ConstantInt::getFalse(RHS->getContext());
2697  if (Pred == ICmpInst::ICMP_ULE)
2698  return ConstantInt::getTrue(RHS->getContext());
2699  }
2700  }
2701  }
2702 
2703  if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2704  LBO->getOperand(1) == RBO->getOperand(1)) {
2705  switch (LBO->getOpcode()) {
2706  default:
2707  break;
2708  case Instruction::UDiv:
2709  case Instruction::LShr:
2710  if (ICmpInst::isSigned(Pred) || !LBO->isExact() || !RBO->isExact())
2711  break;
2712  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2713  RBO->getOperand(0), Q, MaxRecurse - 1))
2714  return V;
2715  break;
2716  case Instruction::SDiv:
2717  if (!ICmpInst::isEquality(Pred) || !LBO->isExact() || !RBO->isExact())
2718  break;
2719  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2720  RBO->getOperand(0), Q, MaxRecurse - 1))
2721  return V;
2722  break;
2723  case Instruction::AShr:
2724  if (!LBO->isExact() || !RBO->isExact())
2725  break;
2726  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2727  RBO->getOperand(0), Q, MaxRecurse - 1))
2728  return V;
2729  break;
2730  case Instruction::Shl: {
2731  bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2732  bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2733  if (!NUW && !NSW)
2734  break;
2735  if (!NSW && ICmpInst::isSigned(Pred))
2736  break;
2737  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2738  RBO->getOperand(0), Q, MaxRecurse - 1))
2739  return V;
2740  break;
2741  }
2742  }
2743  }
2744  return nullptr;
2745 }
2746 
2747 /// Simplify integer comparisons where at least one operand of the compare
2748 /// matches an integer min/max idiom.
2750  Value *RHS, const SimplifyQuery &Q,
2751  unsigned MaxRecurse) {
2752  Type *ITy = GetCompareTy(LHS); // The return type.
2753  Value *A, *B;
2755  CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2756 
2757  // Signed variants on "max(a,b)>=a -> true".
2758  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2759  if (A != RHS)
2760  std::swap(A, B); // smax(A, B) pred A.
2761  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2762  // We analyze this as smax(A, B) pred A.
2763  P = Pred;
2764  } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2765  (A == LHS || B == LHS)) {
2766  if (A != LHS)
2767  std::swap(A, B); // A pred smax(A, B).
2768  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2769  // We analyze this as smax(A, B) swapped-pred A.
2770  P = CmpInst::getSwappedPredicate(Pred);
2771  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2772  (A == RHS || B == RHS)) {
2773  if (A != RHS)
2774  std::swap(A, B); // smin(A, B) pred A.
2775  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2776  // We analyze this as smax(-A, -B) swapped-pred -A.
2777  // Note that we do not need to actually form -A or -B thanks to EqP.
2778  P = CmpInst::getSwappedPredicate(Pred);
2779  } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2780  (A == LHS || B == LHS)) {
2781  if (A != LHS)
2782  std::swap(A, B); // A pred smin(A, B).
2783  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2784  // We analyze this as smax(-A, -B) pred -A.
2785  // Note that we do not need to actually form -A or -B thanks to EqP.
2786  P = Pred;
2787  }
2788  if (P != CmpInst::BAD_ICMP_PREDICATE) {
2789  // Cases correspond to "max(A, B) p A".
2790  switch (P) {
2791  default:
2792  break;
2793  case CmpInst::ICMP_EQ:
2794  case CmpInst::ICMP_SLE:
2795  // Equivalent to "A EqP B". This may be the same as the condition tested
2796  // in the max/min; if so, we can just return that.
2797  if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2798  return V;
2799  if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2800  return V;
2801  // Otherwise, see if "A EqP B" simplifies.
2802  if (MaxRecurse)
2803  if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
2804  return V;
2805  break;
2806  case CmpInst::ICMP_NE:
2807  case CmpInst::ICMP_SGT: {
2809  // Equivalent to "A InvEqP B". This may be the same as the condition
2810  // tested in the max/min; if so, we can just return that.
2811  if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2812  return V;
2813  if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2814  return V;
2815  // Otherwise, see if "A InvEqP B" simplifies.
2816  if (MaxRecurse)
2817  if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
2818  return V;
2819  break;
2820  }
2821  case CmpInst::ICMP_SGE:
2822  // Always true.
2823  return getTrue(ITy);
2824  case CmpInst::ICMP_SLT:
2825  // Always false.
2826  return getFalse(ITy);
2827  }
2828  }
2829 
2830  // Unsigned variants on "max(a,b)>=a -> true".
2832  if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2833  if (A != RHS)
2834  std::swap(A, B); // umax(A, B) pred A.
2835  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2836  // We analyze this as umax(A, B) pred A.
2837  P = Pred;
2838  } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2839  (A == LHS || B == LHS)) {
2840  if (A != LHS)
2841  std::swap(A, B); // A pred umax(A, B).
2842  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2843  // We analyze this as umax(A, B) swapped-pred A.
2844  P = CmpInst::getSwappedPredicate(Pred);
2845  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2846  (A == RHS || B == RHS)) {
2847  if (A != RHS)
2848  std::swap(A, B); // umin(A, B) pred A.
2849  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2850  // We analyze this as umax(-A, -B) swapped-pred -A.
2851  // Note that we do not need to actually form -A or -B thanks to EqP.
2852  P = CmpInst::getSwappedPredicate(Pred);
2853  } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2854  (A == LHS || B == LHS)) {
2855  if (A != LHS)
2856  std::swap(A, B); // A pred umin(A, B).
2857  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2858  // We analyze this as umax(-A, -B) pred -A.
2859  // Note that we do not need to actually form -A or -B thanks to EqP.
2860  P = Pred;
2861  }
2862  if (P != CmpInst::BAD_ICMP_PREDICATE) {
2863  // Cases correspond to "max(A, B) p A".
2864  switch (P) {
2865  default:
2866  break;
2867  case CmpInst::ICMP_EQ:
2868  case CmpInst::ICMP_ULE:
2869  // Equivalent to "A EqP B". This may be the same as the condition tested
2870  // in the max/min; if so, we can just return that.
2871  if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2872  return V;
2873  if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2874  return V;
2875  // Otherwise, see if "A EqP B" simplifies.
2876  if (MaxRecurse)
2877  if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
2878  return V;
2879  break;
2880  case CmpInst::ICMP_NE:
2881  case CmpInst::ICMP_UGT: {
2883  // Equivalent to "A InvEqP B". This may be the same as the condition
2884  // tested in the max/min; if so, we can just return that.
2885  if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2886  return V;
2887  if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2888  return V;
2889  // Otherwise, see if "A InvEqP B" simplifies.
2890  if (MaxRecurse)
2891  if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
2892  return V;
2893  break;
2894  }
2895  case CmpInst::ICMP_UGE:
2896  // Always true.
2897  return getTrue(ITy);
2898  case CmpInst::ICMP_ULT:
2899  // Always false.
2900  return getFalse(ITy);
2901  }
2902  }
2903 
2904  // Variants on "max(x,y) >= min(x,z)".
2905  Value *C, *D;
2906  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2907  match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2908  (A == C || A == D || B == C || B == D)) {
2909  // max(x, ?) pred min(x, ?).
2910  if (Pred == CmpInst::ICMP_SGE)
2911  // Always true.
2912  return getTrue(ITy);
2913  if (Pred == CmpInst::ICMP_SLT)
2914  // Always false.
2915  return getFalse(ITy);
2916  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2917  match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2918  (A == C || A == D || B == C || B == D)) {
2919  // min(x, ?) pred max(x, ?).
2920  if (Pred == CmpInst::ICMP_SLE)
2921  // Always true.
2922  return getTrue(ITy);
2923  if (Pred == CmpInst::ICMP_SGT)
2924  // Always false.
2925  return getFalse(ITy);
2926  } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2927  match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2928  (A == C || A == D || B == C || B == D)) {
2929  // max(x, ?) pred min(x, ?).
2930  if (Pred == CmpInst::ICMP_UGE)
2931  // Always true.
2932  return getTrue(ITy);
2933  if (Pred == CmpInst::ICMP_ULT)
2934  // Always false.
2935  return getFalse(ITy);
2936  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2937  match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2938  (A == C || A == D || B == C || B == D)) {
2939  // min(x, ?) pred max(x, ?).
2940  if (Pred == CmpInst::ICMP_ULE)
2941  // Always true.
2942  return getTrue(ITy);
2943  if (Pred == CmpInst::ICMP_UGT)
2944  // Always false.
2945  return getFalse(ITy);
2946  }
2947 
2948  return nullptr;
2949 }
2950 
2951 /// Given operands for an ICmpInst, see if we can fold the result.
2952 /// If not, this returns null.
2953 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2954  const SimplifyQuery &Q, unsigned MaxRecurse) {
2955  CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2956  assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
2957 
2958  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2959  if (Constant *CRHS = dyn_cast<Constant>(RHS))
2960  return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
2961 
2962  // If we have a constant, make sure it is on the RHS.
2963  std::swap(LHS, RHS);
2964  Pred = CmpInst::getSwappedPredicate(Pred);
2965  }
2966 
2967  Type *ITy = GetCompareTy(LHS); // The return type.
2968 
2969  // icmp X, X -> true/false
2970  // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
2971  // because X could be 0.
2972  if (LHS == RHS || isa<UndefValue>(RHS))
2973  return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
2974 
2975  if (Value *V = simplifyICmpOfBools(Pred, LHS, RHS, Q))
2976  return V;
2977 
2978  if (Value *V = simplifyICmpWithZero(Pred, LHS, RHS, Q))
2979  return V;
2980 
2981  if (Value *V = simplifyICmpWithConstant(Pred, LHS, RHS))
2982  return V;
2983 
2984  // If both operands have range metadata, use the metadata
2985  // to simplify the comparison.
2986  if (isa<Instruction>(RHS) && isa<Instruction>(LHS)) {
2987  auto RHS_Instr = cast<Instruction>(RHS);
2988  auto LHS_Instr = cast<Instruction>(LHS);
2989 
2990  if (RHS_Instr->getMetadata(LLVMContext::MD_range) &&
2991  LHS_Instr->getMetadata(LLVMContext::MD_range)) {
2992  auto RHS_CR = getConstantRangeFromMetadata(
2993  *RHS_Instr->getMetadata(LLVMContext::MD_range));
2994  auto LHS_CR = getConstantRangeFromMetadata(
2995  *LHS_Instr->getMetadata(LLVMContext::MD_range));
2996 
2997  auto Satisfied_CR = ConstantRange::makeSatisfyingICmpRegion(Pred, RHS_CR);
2998  if (Satisfied_CR.contains(LHS_CR))
2999  return ConstantInt::getTrue(RHS->getContext());
3000 
3001  auto InversedSatisfied_CR = ConstantRange::makeSatisfyingICmpRegion(
3002  CmpInst::getInversePredicate(Pred), RHS_CR);
3003  if (InversedSatisfied_CR.contains(LHS_CR))
3004  return ConstantInt::getFalse(RHS->getContext());
3005  }
3006  }
3007 
3008  // Compare of cast, for example (zext X) != 0 -> X != 0
3009  if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
3010  Instruction *LI = cast<CastInst>(LHS);
3011  Value *SrcOp = LI->getOperand(0);
3012  Type *SrcTy = SrcOp->getType();
3013  Type *DstTy = LI->getType();
3014 
3015  // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
3016  // if the integer type is the same size as the pointer type.
3017  if (MaxRecurse && isa<PtrToIntInst>(LI) &&
3018  Q.DL.getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
3019  if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
3020  // Transfer the cast to the constant.
3021  if (Value *V = SimplifyICmpInst(Pred, SrcOp,
3022  ConstantExpr::getIntToPtr(RHSC, SrcTy),
3023  Q, MaxRecurse-1))
3024  return V;
3025  } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
3026  if (RI->getOperand(0)->getType() == SrcTy)
3027  // Compare without the cast.
3028  if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
3029  Q, MaxRecurse-1))
3030  return V;
3031  }
3032  }
3033 
3034  if (isa<ZExtInst>(LHS)) {
3035  // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
3036  // same type.
3037  if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
3038  if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3039  // Compare X and Y. Note that signed predicates become unsigned.
3041  SrcOp, RI->getOperand(0), Q,
3042  MaxRecurse-1))
3043  return V;
3044  }
3045  // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
3046  // too. If not, then try to deduce the result of the comparison.
3047  else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3048  // Compute the constant that would happen if we truncated to SrcTy then
3049  // reextended to DstTy.
3050  Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3051  Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
3052 
3053  // If the re-extended constant didn't change then this is effectively
3054  // also a case of comparing two zero-extended values.
3055  if (RExt == CI && MaxRecurse)
3057  SrcOp, Trunc, Q, MaxRecurse-1))
3058  return V;
3059 
3060  // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
3061  // there. Use this to work out the result of the comparison.
3062  if (RExt != CI) {
3063  switch (Pred) {
3064  default: llvm_unreachable("Unknown ICmp predicate!");
3065  // LHS <u RHS.
3066  case ICmpInst::ICMP_EQ:
3067  case ICmpInst::ICMP_UGT:
3068  case ICmpInst::ICMP_UGE:
3069  return ConstantInt::getFalse(CI->getContext());
3070 
3071  case ICmpInst::ICMP_NE:
3072  case ICmpInst::ICMP_ULT:
3073  case ICmpInst::ICMP_ULE:
3074  return ConstantInt::getTrue(CI->getContext());
3075 
3076  // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
3077  // is non-negative then LHS <s RHS.
3078  case ICmpInst::ICMP_SGT:
3079  case ICmpInst::ICMP_SGE:
3080  return CI->getValue().isNegative() ?
3081  ConstantInt::getTrue(CI->getContext()) :
3082  ConstantInt::getFalse(CI->getContext());
3083 
3084  case ICmpInst::ICMP_SLT:
3085  case ICmpInst::ICMP_SLE:
3086  return CI->getValue().isNegative() ?
3087  ConstantInt::getFalse(CI->getContext()) :
3088  ConstantInt::getTrue(CI->getContext());
3089  }
3090  }
3091  }
3092  }
3093 
3094  if (isa<SExtInst>(LHS)) {
3095  // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
3096  // same type.
3097  if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
3098  if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3099  // Compare X and Y. Note that the predicate does not change.
3100  if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
3101  Q, MaxRecurse-1))
3102  return V;
3103  }
3104  // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
3105  // too. If not, then try to deduce the result of the comparison.
3106  else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3107  // Compute the constant that would happen if we truncated to SrcTy then
3108  // reextended to DstTy.
3109  Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3110  Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
3111 
3112  // If the re-extended constant didn't change then this is effectively
3113  // also a case of comparing two sign-extended values.
3114  if (RExt == CI && MaxRecurse)
3115  if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
3116  return V;
3117 
3118  // Otherwise the upper bits of LHS are all equal, while RHS has varying
3119  // bits there. Use this to work out the result of the comparison.
3120  if (RExt != CI) {
3121  switch (Pred) {
3122  default: llvm_unreachable("Unknown ICmp predicate!");
3123  case ICmpInst::ICMP_EQ:
3124  return ConstantInt::getFalse(CI->getContext());
3125  case ICmpInst::ICMP_NE:
3126  return ConstantInt::getTrue(CI->getContext());
3127 
3128  // If RHS is non-negative then LHS <s RHS. If RHS is negative then
3129  // LHS >s RHS.
3130  case ICmpInst::ICMP_SGT:
3131  case ICmpInst::ICMP_SGE:
3132  return CI->getValue().isNegative() ?
3133  ConstantInt::getTrue(CI->getContext()) :
3134  ConstantInt::getFalse(CI->getContext());
3135  case ICmpInst::ICMP_SLT:
3136  case ICmpInst::ICMP_SLE:
3137  return CI->getValue().isNegative() ?
3138  ConstantInt::getFalse(CI->getContext()) :
3139  ConstantInt::getTrue(CI->getContext());
3140 
3141  // If LHS is non-negative then LHS <u RHS. If LHS is negative then
3142  // LHS >u RHS.
3143  case ICmpInst::ICMP_UGT:
3144  case ICmpInst::ICMP_UGE:
3145  // Comparison is true iff the LHS <s 0.
3146  if (MaxRecurse)
3147  if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
3148  Constant::getNullValue(SrcTy),
3149  Q, MaxRecurse-1))
3150  return V;
3151  break;
3152  case ICmpInst::ICMP_ULT:
3153  case ICmpInst::ICMP_ULE:
3154  // Comparison is true iff the LHS >=s 0.
3155  if (MaxRecurse)
3156  if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
3157  Constant::getNullValue(SrcTy),
3158  Q, MaxRecurse-1))
3159  return V;
3160  break;
3161  }
3162  }
3163  }
3164  }
3165  }
3166 
3167  // icmp eq|ne X, Y -> false|true if X != Y
3168  if (ICmpInst::isEquality(Pred) &&
3169  isKnownNonEqual(LHS, RHS, Q.DL, Q.AC, Q.CxtI, Q.DT)) {
3170  return Pred == ICmpInst::ICMP_NE ? getTrue(ITy) : getFalse(ITy);
3171  }
3172 
3173  if (Value *V = simplifyICmpWithBinOp(Pred, LHS, RHS, Q, MaxRecurse))
3174  return V;
3175 
3176  if (Value *V = simplifyICmpWithMinMax(Pred, LHS, RHS, Q, MaxRecurse))
3177  return V;
3178 
3179  // Simplify comparisons of related pointers using a powerful, recursive
3180  // GEP-walk when we have target data available..
3181  if (LHS->getType()->isPointerTy())
3182  if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI, LHS,
3183  RHS))
3184  return C;
3185  if (auto *CLHS = dyn_cast<PtrToIntOperator>(LHS))
3186  if (auto *CRHS = dyn_cast<PtrToIntOperator>(RHS))
3187  if (Q.DL.getTypeSizeInBits(CLHS->getPointerOperandType()) ==
3188  Q.DL.getTypeSizeInBits(CLHS->getType()) &&
3189  Q.DL.getTypeSizeInBits(CRHS->getPointerOperandType()) ==
3190  Q.DL.getTypeSizeInBits(CRHS->getType()))
3191  if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI,
3192  CLHS->getPointerOperand(),
3193  CRHS->getPointerOperand()))
3194  return C;
3195 
3196  if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
3197  if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
3198  if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
3199  GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
3200  (ICmpInst::isEquality(Pred) ||
3201  (GLHS->isInBounds() && GRHS->isInBounds() &&
3202  Pred == ICmpInst::getSignedPredicate(Pred)))) {
3203  // The bases are equal and the indices are constant. Build a constant
3204  // expression GEP with the same indices and a null base pointer to see
3205  // what constant folding can make out of it.
3206  Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
3207  SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
3209  GLHS->getSourceElementType(), Null, IndicesLHS);
3210 
3211  SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
3213  GLHS->getSourceElementType(), Null, IndicesRHS);
3214  return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
3215  }
3216  }
3217  }
3218 
3219  // If the comparison is with the result of a select instruction, check whether
3220  // comparing with either branch of the select always yields the same value.
3221  if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3222  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3223  return V;
3224 
3225  // If the comparison is with the result of a phi instruction, check whether
3226  // doing the compare with each incoming phi value yields a common result.
3227  if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3228  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3229  return V;
3230 
3231  return nullptr;
3232 }
3233 
3234 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3235  const SimplifyQuery &Q) {
3236  return ::SimplifyICmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
3237 }
3238 
3239 /// Given operands for an FCmpInst, see if we can fold the result.
3240 /// If not, this returns null.
3241 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3242  FastMathFlags FMF, const SimplifyQuery &Q,
3243  unsigned MaxRecurse) {
3244  CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3245  assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
3246 
3247  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3248  if (Constant *CRHS = dyn_cast<Constant>(RHS))
3249  return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3250 
3251  // If we have a constant, make sure it is on the RHS.
3252  std::swap(LHS, RHS);
3253  Pred = CmpInst::getSwappedPredicate(Pred);
3254  }
3255 
3256  // Fold trivial predicates.
3257  Type *RetTy = GetCompareTy(LHS);
3258  if (Pred == FCmpInst::FCMP_FALSE)
3259  return getFalse(RetTy);
3260  if (Pred == FCmpInst::FCMP_TRUE)
3261  return getTrue(RetTy);
3262 
3263  // UNO/ORD predicates can be trivially folded if NaNs are ignored.
3264  if (FMF.noNaNs()) {
3265  if (Pred == FCmpInst::FCMP_UNO)
3266  return getFalse(RetTy);
3267  if (Pred == FCmpInst::FCMP_ORD)
3268  return getTrue(RetTy);
3269  }
3270 
3271  // fcmp pred x, undef and fcmp pred undef, x
3272  // fold to true if unordered, false if ordered
3273  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS)) {
3274  // Choosing NaN for the undef will always make unordered comparison succeed
3275  // and ordered comparison fail.
3276  return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred));
3277  }
3278 
3279  // fcmp x,x -> true/false. Not all compares are foldable.
3280  if (LHS == RHS) {
3281  if (CmpInst::isTrueWhenEqual(Pred))
3282  return getTrue(RetTy);
3283  if (CmpInst::isFalseWhenEqual(Pred))
3284  return getFalse(RetTy);
3285  }
3286 
3287  // Handle fcmp with constant RHS
3288  const ConstantFP *CFP = nullptr;
3289  if (const auto *RHSC = dyn_cast<Constant>(RHS)) {
3290  if (RHS->getType()->isVectorTy())
3291  CFP = dyn_cast_or_null<ConstantFP>(RHSC->getSplatValue());
3292  else
3293  CFP = dyn_cast<ConstantFP>(RHSC);
3294  }
3295  if (CFP) {
3296  // If the constant is a nan, see if we can fold the comparison based on it.
3297  if (CFP->getValueAPF().isNaN()) {
3298  if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
3299  return getFalse(RetTy);
3300  assert(FCmpInst::isUnordered(Pred) &&
3301  "Comparison must be either ordered or unordered!");
3302  // True if unordered.
3303  return getTrue(RetTy);
3304  }
3305  // Check whether the constant is an infinity.
3306  if (CFP->getValueAPF().isInfinity()) {
3307  if (CFP->getValueAPF().isNegative()) {
3308  switch (Pred) {
3309  case FCmpInst::FCMP_OLT:
3310  // No value is ordered and less than negative infinity.
3311  return getFalse(RetTy);
3312  case FCmpInst::FCMP_UGE:
3313  // All values are unordered with or at least negative infinity.
3314  return getTrue(RetTy);
3315  default:
3316  break;
3317  }
3318  } else {
3319  switch (Pred) {
3320  case FCmpInst::FCMP_OGT:
3321  // No value is ordered and greater than infinity.
3322  return getFalse(RetTy);
3323  case FCmpInst::FCMP_ULE:
3324  // All values are unordered with and at most infinity.
3325  return getTrue(RetTy);
3326  default:
3327  break;
3328  }
3329  }
3330  }
3331  if (CFP->getValueAPF().isZero()) {
3332  switch (Pred) {
3333  case FCmpInst::FCMP_UGE:
3334  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3335  return getTrue(RetTy);
3336  break;
3337  case FCmpInst::FCMP_OLT:
3338  // X < 0
3339  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3340  return getFalse(RetTy);
3341  break;
3342  default:
3343  break;
3344  }
3345  }
3346  }
3347 
3348  // If the comparison is with the result of a select instruction, check whether
3349  // comparing with either branch of the select always yields the same value.
3350  if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3351  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3352  return V;
3353 
3354  // If the comparison is with the result of a phi instruction, check whether
3355  // doing the compare with each incoming phi value yields a common result.
3356  if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3357  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3358  return V;
3359 
3360  return nullptr;
3361 }
3362 
3363 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3364  FastMathFlags FMF, const SimplifyQuery &Q) {
3365  return ::SimplifyFCmpInst(Predicate, LHS, RHS, FMF, Q, RecursionLimit);
3366 }
3367 
3368 /// See if V simplifies when its operand Op is replaced with RepOp.
3369 static const Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
3370  const SimplifyQuery &Q,
3371  unsigned MaxRecurse) {
3372  // Trivial replacement.
3373  if (V == Op)
3374  return RepOp;
3375 
3376  // We cannot replace a constant, and shouldn't even try.
3377  if (isa<Constant>(Op))
3378  return nullptr;
3379 
3380  auto *I = dyn_cast<Instruction>(V);
3381  if (!I)
3382  return nullptr;
3383 
3384  // If this is a binary operator, try to simplify it with the replaced op.
3385  if (auto *B = dyn_cast<BinaryOperator>(I)) {
3386  // Consider:
3387  // %cmp = icmp eq i32 %x, 2147483647
3388  // %add = add nsw i32 %x, 1
3389  // %sel = select i1 %cmp, i32 -2147483648, i32 %add
3390  //
3391  // We can't replace %sel with %add unless we strip away the flags.
3392  if (isa<OverflowingBinaryOperator>(B))
3393  if (B->hasNoSignedWrap() || B->hasNoUnsignedWrap())
3394  return nullptr;
3395  if (isa<PossiblyExactOperator>(B))
3396  if (B->isExact())
3397  return nullptr;
3398 
3399  if (MaxRecurse) {
3400  if (B->getOperand(0) == Op)
3401  return SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), Q,
3402  MaxRecurse - 1);
3403  if (B->getOperand(1) == Op)
3404  return SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, Q,
3405  MaxRecurse - 1);
3406  }
3407  }
3408 
3409  // Same for CmpInsts.
3410  if (CmpInst *C = dyn_cast<CmpInst>(I)) {
3411  if (MaxRecurse) {
3412  if (C->getOperand(0) == Op)
3413  return SimplifyCmpInst(C->getPredicate(), RepOp, C->getOperand(1), Q,
3414  MaxRecurse - 1);
3415  if (C->getOperand(1) == Op)
3416  return SimplifyCmpInst(C->getPredicate(), C->getOperand(0), RepOp, Q,
3417  MaxRecurse - 1);
3418  }
3419  }
3420 
3421  // TODO: We could hand off more cases to instsimplify here.
3422 
3423  // If all operands are constant after substituting Op for RepOp then we can
3424  // constant fold the instruction.
3425  if (Constant *CRepOp = dyn_cast<Constant>(RepOp)) {
3426  // Build a list of all constant operands.
3427  SmallVector<Constant *, 8> ConstOps;
3428  for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
3429  if (I->getOperand(i) == Op)
3430  ConstOps.push_back(CRepOp);
3431  else if (Constant *COp = dyn_cast<Constant>(I->getOperand(i)))
3432  ConstOps.push_back(COp);
3433  else
3434  break;
3435  }
3436 
3437  // All operands were constants, fold it.
3438  if (ConstOps.size() == I->getNumOperands()) {
3439  if (CmpInst *C = dyn_cast<CmpInst>(I))
3440  return ConstantFoldCompareInstOperands(C->getPredicate(), ConstOps[0],
3441  ConstOps[1], Q.DL, Q.TLI);
3442 
3443  if (LoadInst *LI = dyn_cast<LoadInst>(I))
3444  if (!LI->isVolatile())
3445  return ConstantFoldLoadFromConstPtr(ConstOps[0], LI->getType(), Q.DL);
3446 
3447  return ConstantFoldInstOperands(I, ConstOps, Q.DL, Q.TLI);
3448  }
3449  }
3450 
3451  return nullptr;
3452 }
3453 
3454 /// Try to simplify a select instruction when its condition operand is an
3455 /// integer comparison where one operand of the compare is a constant.
3456 static Value *simplifySelectBitTest(Value *TrueVal, Value *FalseVal, Value *X,
3457  const APInt *Y, bool TrueWhenUnset) {
3458  const APInt *C;
3459 
3460  // (X & Y) == 0 ? X & ~Y : X --> X
3461  // (X & Y) != 0 ? X & ~Y : X --> X & ~Y
3462  if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) &&
3463  *Y == ~*C)
3464  return TrueWhenUnset ? FalseVal : TrueVal;
3465 
3466  // (X & Y) == 0 ? X : X & ~Y --> X & ~Y
3467  // (X & Y) != 0 ? X : X & ~Y --> X
3468  if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) &&
3469  *Y == ~*C)
3470  return TrueWhenUnset ? FalseVal : TrueVal;
3471 
3472  if (Y->isPowerOf2()) {
3473  // (X & Y) == 0 ? X | Y : X --> X | Y
3474  // (X & Y) != 0 ? X | Y : X --> X
3475  if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) &&
3476  *Y == *C)
3477  return TrueWhenUnset ? TrueVal : FalseVal;
3478 
3479  // (X & Y) == 0 ? X : X | Y --> X
3480  // (X & Y) != 0 ? X : X | Y --> X | Y
3481  if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) &&
3482  *Y == *C)
3483  return TrueWhenUnset ? TrueVal : FalseVal;
3484  }
3485 
3486  return nullptr;
3487 }
3488 
3489 /// An alternative way to test if a bit is set or not uses sgt/slt instead of
3490 /// eq/ne.
3492  ICmpInst::Predicate Pred,
3493  Value *TrueVal, Value *FalseVal) {
3494  Value *X;
3495  APInt Mask;
3496  if (!decomposeBitTestICmp(CmpLHS, CmpRHS, Pred, X, Mask))
3497  return nullptr;
3498 
3499  return simplifySelectBitTest(TrueVal, FalseVal, X, &Mask,
3500  Pred == ICmpInst::ICMP_EQ);
3501 }
3502 
3503 /// Try to simplify a select instruction when its condition operand is an
3504 /// integer comparison.
3505 static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
3506  Value *FalseVal, const SimplifyQuery &Q,
3507  unsigned MaxRecurse) {
3508  ICmpInst::Predicate Pred;
3509  Value *CmpLHS, *CmpRHS;
3510  if (!match(CondVal, m_ICmp(Pred, m_Value(CmpLHS), m_Value(CmpRHS))))
3511  return nullptr;
3512 
3513  if (ICmpInst::isEquality(Pred) && match(CmpRHS, m_Zero())) {
3514  Value *X;
3515  const APInt *Y;
3516  if (match(CmpLHS, m_And(m_Value(X), m_APInt(Y))))
3517  if (Value *V = simplifySelectBitTest(TrueVal, FalseVal, X, Y,
3518  Pred == ICmpInst::ICMP_EQ))
3519  return V;
3520  }
3521 
3522  // Check for other compares that behave like bit test.
3523  if (Value *V = simplifySelectWithFakeICmpEq(CmpLHS, CmpRHS, Pred,
3524  TrueVal, FalseVal))
3525  return V;
3526 
3527  if (CondVal->hasOneUse()) {
3528  const APInt *C;
3529  if (match(CmpRHS, m_APInt(C))) {
3530  // X < MIN ? T : F --> F
3531  if (Pred == ICmpInst::ICMP_SLT && C->isMinSignedValue())
3532  return FalseVal;
3533  // X < MIN ? T : F --> F
3534  if (Pred == ICmpInst::ICMP_ULT && C->isMinValue())
3535  return FalseVal;
3536  // X > MAX ? T : F --> F
3537  if (Pred == ICmpInst::ICMP_SGT && C->isMaxSignedValue())
3538  return FalseVal;
3539  // X > MAX ? T : F --> F
3540  if (Pred == ICmpInst::ICMP_UGT && C->isMaxValue())
3541  return FalseVal;
3542  }
3543  }
3544 
3545  // If we have an equality comparison, then we know the value in one of the
3546  // arms of the select. See if substituting this value into the arm and
3547  // simplifying the result yields the same value as the other arm.
3548  if (Pred == ICmpInst::ICMP_EQ) {
3549  if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3550  TrueVal ||
3551  SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3552  TrueVal)
3553  return FalseVal;
3554  if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3555  FalseVal ||
3556  SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3557  FalseVal)
3558  return FalseVal;
3559  } else if (Pred == ICmpInst::ICMP_NE) {
3560  if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3561  FalseVal ||
3562  SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3563  FalseVal)
3564  return TrueVal;
3565  if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3566  TrueVal ||
3567  SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3568  TrueVal)
3569  return TrueVal;
3570  }
3571 
3572  return nullptr;
3573 }
3574 
3575 /// Given operands for a SelectInst, see if we can fold the result.
3576 /// If not, this returns null.
3577 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
3578  Value *FalseVal, const SimplifyQuery &Q,
3579  unsigned MaxRecurse) {
3580  // select true, X, Y -> X
3581  // select false, X, Y -> Y
3582  if (Constant *CB = dyn_cast<Constant>(CondVal)) {
3583  if (CB->isAllOnesValue())
3584  return TrueVal;
3585  if (CB->isNullValue())
3586  return FalseVal;
3587  }
3588 
3589  // select C, X, X -> X
3590  if (TrueVal == FalseVal)
3591  return TrueVal;
3592 
3593  if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
3594  if (isa<Constant>(FalseVal))
3595  return FalseVal;
3596  return TrueVal;
3597  }
3598  if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
3599  return FalseVal;
3600  if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
3601  return TrueVal;
3602 
3603  if (Value *V =
3604  simplifySelectWithICmpCond(CondVal, TrueVal, FalseVal, Q, MaxRecurse))
3605  return V;
3606 
3607  return nullptr;
3608 }
3609 
3610 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3611  const SimplifyQuery &Q) {
3612  return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Q, RecursionLimit);
3613 }
3614 
3615 /// Given operands for an GetElementPtrInst, see if we can fold the result.
3616 /// If not, this returns null.
3618  const SimplifyQuery &Q, unsigned) {
3619  // The type of the GEP pointer operand.
3620  unsigned AS =
3621  cast<PointerType>(Ops[0]->getType()->getScalarType())->getAddressSpace();
3622 
3623  // getelementptr P -> P.
3624  if (Ops.size() == 1)
3625  return Ops[0];
3626 
3627  // Compute the (pointer) type returned by the GEP instruction.
3628  Type *LastType = GetElementPtrInst::getIndexedType(SrcTy, Ops.slice(1));
3629  Type *GEPTy = PointerType::get(LastType, AS);
3630  if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
3631  GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3632  else if (VectorType *VT = dyn_cast<VectorType>(Ops[1]->getType()))
3633  GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3634 
3635  if (isa<UndefValue>(Ops[0]))
3636  return UndefValue::get(GEPTy);
3637 
3638  if (Ops.size() == 2) {
3639  // getelementptr P, 0 -> P.
3640  if (match(Ops[1], m_Zero()))
3641  return Ops[0];
3642 
3643  Type *Ty = SrcTy;
3644  if (Ty->isSized()) {
3645  Value *P;
3646  uint64_t C;
3647  uint64_t TyAllocSize = Q.DL.getTypeAllocSize(Ty);
3648  // getelementptr P, N -> P if P points to a type of zero size.
3649  if (TyAllocSize == 0)
3650  return Ops[0];
3651 
3652  // The following transforms are only safe if the ptrtoint cast
3653  // doesn't truncate the pointers.
3654  if (Ops[1]->getType()->getScalarSizeInBits() ==
3655  Q.DL.getPointerSizeInBits(AS)) {
3656  auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
3657  if (match(P, m_Zero()))
3658  return Constant::getNullValue(GEPTy);
3659  Value *Temp;
3660  if (match(P, m_PtrToInt(m_Value(Temp))))
3661  if (Temp->getType() == GEPTy)
3662  return Temp;
3663  return nullptr;
3664  };
3665 
3666  // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
3667  if (TyAllocSize == 1 &&
3668  match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
3669  if (Value *R = PtrToIntOrZero(P))
3670  return R;
3671 
3672  // getelementptr V, (ashr (sub P, V), C) -> Q
3673  // if P points to a type of size 1 << C.
3674  if (match(Ops[1],
3675  m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3676  m_ConstantInt(C))) &&
3677  TyAllocSize == 1ULL << C)
3678  if (Value *R = PtrToIntOrZero(P))
3679  return R;
3680 
3681  // getelementptr V, (sdiv (sub P, V), C) -> Q
3682  // if P points to a type of size C.
3683  if (match(Ops[1],
3684  m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3685  m_SpecificInt(TyAllocSize))))
3686  if (Value *R = PtrToIntOrZero(P))
3687  return R;
3688  }
3689  }
3690  }
3691 
3692  if (Q.DL.getTypeAllocSize(LastType) == 1 &&
3693  all_of(Ops.slice(1).drop_back(1),
3694  [](Value *Idx) { return match(Idx, m_Zero()); })) {
3695  unsigned PtrWidth =
3696  Q.DL.getPointerSizeInBits(Ops[0]->getType()->getPointerAddressSpace());
3697  if (Q.DL.getTypeSizeInBits(Ops.back()->getType()) == PtrWidth) {
3698  APInt BasePtrOffset(PtrWidth, 0);
3699  Value *StrippedBasePtr =
3700  Ops[0]->stripAndAccumulateInBoundsConstantOffsets(Q.DL,
3701  BasePtrOffset);
3702 
3703  // gep (gep V, C), (sub 0, V) -> C
3704  if (match(Ops.back(),
3705  m_Sub(m_Zero(), m_PtrToInt(m_Specific(StrippedBasePtr))))) {
3706  auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset);
3707  return ConstantExpr::getIntToPtr(CI, GEPTy);
3708  }
3709  // gep (gep V, C), (xor V, -1) -> C-1
3710  if (match(Ops.back(),
3711  m_Xor(m_PtrToInt(m_Specific(StrippedBasePtr)), m_AllOnes()))) {
3712  auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset - 1);
3713  return ConstantExpr::getIntToPtr(CI, GEPTy);
3714  }
3715  }
3716  }
3717 
3718  // Check to see if this is constant foldable.
3719  if (!all_of(Ops, [](Value *V) { return isa<Constant>(V); }))
3720  return nullptr;
3721 
3722  auto *CE = ConstantExpr::getGetElementPtr(SrcTy, cast<Constant>(Ops[0]),
3723  Ops.slice(1));
3724  if (auto *CEFolded = ConstantFoldConstant(CE, Q.DL))
3725  return CEFolded;
3726  return CE;
3727 }
3728 
3730  const SimplifyQuery &Q) {
3731  return ::SimplifyGEPInst(SrcTy, Ops, Q, RecursionLimit);
3732 }
3733 
3734 /// Given operands for an InsertValueInst, see if we can fold the result.
3735 /// If not, this returns null.
3737  ArrayRef<unsigned> Idxs, const SimplifyQuery &Q,
3738  unsigned) {
3739  if (Constant *CAgg = dyn_cast<Constant>(Agg))
3740  if (Constant *CVal = dyn_cast<Constant>(Val))
3741  return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
3742 
3743  // insertvalue x, undef, n -> x
3744  if (match(Val, m_Undef()))
3745  return Agg;
3746 
3747  // insertvalue x, (extractvalue y, n), n
3748  if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
3749  if (EV->getAggregateOperand()->getType() == Agg->getType() &&
3750  EV->getIndices() == Idxs) {
3751  // insertvalue undef, (extractvalue y, n), n -> y
3752  if (match(Agg, m_Undef()))
3753  return EV->getAggregateOperand();
3754 
3755  // insertvalue y, (extractvalue y, n), n -> y
3756  if (Agg == EV->getAggregateOperand())
3757  return Agg;
3758  }
3759 
3760  return nullptr;
3761 }
3762 
3764  ArrayRef<unsigned> Idxs,
3765  const SimplifyQuery &Q) {
3767 }
3768 
3769 /// Given operands for an ExtractValueInst, see if we can fold the result.
3770 /// If not, this returns null.
3772  const SimplifyQuery &, unsigned) {
3773  if (auto *CAgg = dyn_cast<Constant>(Agg))
3774  return ConstantFoldExtractValueInstruction(CAgg, Idxs);
3775 
3776  // extractvalue x, (insertvalue y, elt, n), n -> elt
3777  unsigned NumIdxs = Idxs.size();
3778  for (auto *IVI = dyn_cast<InsertValueInst>(Agg); IVI != nullptr;
3779  IVI = dyn_cast<InsertValueInst>(IVI->getAggregateOperand())) {
3780  ArrayRef<unsigned> InsertValueIdxs = IVI->getIndices();
3781  unsigned NumInsertValueIdxs = InsertValueIdxs.size();
3782  unsigned NumCommonIdxs = std::min(NumInsertValueIdxs, NumIdxs);
3783  if (InsertValueIdxs.slice(0, NumCommonIdxs) ==
3784  Idxs.slice(0, NumCommonIdxs)) {
3785  if (NumIdxs == NumInsertValueIdxs)
3786  return IVI->getInsertedValueOperand();
3787  break;
3788  }
3789  }
3790 
3791  return nullptr;
3792 }
3793 
3795  const SimplifyQuery &Q) {
3797 }
3798 
3799 /// Given operands for an ExtractElementInst, see if we can fold the result.
3800 /// If not, this returns null.
3802  unsigned) {
3803  if (auto *CVec = dyn_cast<Constant>(Vec)) {
3804  if (auto *CIdx = dyn_cast<Constant>(Idx))
3805  return ConstantFoldExtractElementInstruction(CVec, CIdx);
3806 
3807  // The index is not relevant if our vector is a splat.
3808  if (auto *Splat = CVec->getSplatValue())
3809  return Splat;
3810 
3811  if (isa<UndefValue>(Vec))
3812  return UndefValue::get(Vec->getType()->getVectorElementType());
3813  }
3814 
3815  // If extracting a specified index from the vector, see if we can recursively
3816  // find a previously computed scalar that was inserted into the vector.
3817  if (auto *IdxC = dyn_cast<ConstantInt>(Idx))
3818  if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue()))
3819  return Elt;
3820 
3821  return nullptr;
3822 }
3823 
3825  const SimplifyQuery &Q) {
3827 }
3828 
3829 /// See if we can fold the given phi. If not, returns null.
3830 static Value *SimplifyPHINode(PHINode *PN, const SimplifyQuery &Q) {
3831  // If all of the PHI's incoming values are the same then replace the PHI node
3832  // with the common value.
3833  Value *CommonValue = nullptr;
3834  bool HasUndefInput = false;
3835  for (Value *Incoming : PN->incoming_values()) {
3836  // If the incoming value is the phi node itself, it can safely be skipped.
3837  if (Incoming == PN) continue;
3838  if (isa<UndefValue>(Incoming)) {
3839  // Remember that we saw an undef value, but otherwise ignore them.
3840  HasUndefInput = true;
3841  continue;
3842  }
3843  if (CommonValue && Incoming != CommonValue)
3844  return nullptr; // Not the same, bail out.
3845  CommonValue = Incoming;
3846  }
3847 
3848  // If CommonValue is null then all of the incoming values were either undef or
3849  // equal to the phi node itself.
3850  if (!CommonValue)
3851  return UndefValue::get(PN->getType());
3852 
3853  // If we have a PHI node like phi(X, undef, X), where X is defined by some
3854  // instruction, we cannot return X as the result of the PHI node unless it
3855  // dominates the PHI block.
3856  if (HasUndefInput)
3857  return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
3858 
3859  return CommonValue;
3860 }
3861 
3862 static Value *SimplifyCastInst(unsigned CastOpc, Value *Op,
3863  Type *Ty, const SimplifyQuery &Q, unsigned MaxRecurse) {
3864  if (auto *C = dyn_cast<Constant>(Op))
3865  return ConstantFoldCastOperand(CastOpc, C, Ty, Q.DL);
3866 
3867  if (auto *CI = dyn_cast<CastInst>(Op)) {
3868  auto *Src = CI->getOperand(0);
3869  Type *SrcTy = Src->getType();
3870  Type *MidTy = CI->getType();
3871  Type *DstTy = Ty;
3872  if (Src->getType() == Ty) {
3873  auto FirstOp = static_cast<Instruction::CastOps>(CI->getOpcode());
3874  auto SecondOp = static_cast<Instruction::CastOps>(CastOpc);
3875  Type *SrcIntPtrTy =
3876  SrcTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(SrcTy) : nullptr;
3877  Type *MidIntPtrTy =
3878  MidTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(MidTy) : nullptr;
3879  Type *DstIntPtrTy =
3880  DstTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(DstTy) : nullptr;
3881  if (CastInst::isEliminableCastPair(FirstOp, SecondOp, SrcTy, MidTy, DstTy,
3882  SrcIntPtrTy, MidIntPtrTy,
3883  DstIntPtrTy) == Instruction::BitCast)
3884  return Src;
3885  }
3886  }
3887 
3888  // bitcast x -> x
3889  if (CastOpc == Instruction::BitCast)
3890  if (Op->getType() == Ty)
3891  return Op;
3892 
3893  return nullptr;
3894 }
3895 
3896 Value *llvm::SimplifyCastInst(unsigned CastOpc, Value *Op, Type *Ty,
3897  const SimplifyQuery &Q) {
3898  return ::SimplifyCastInst(CastOpc, Op, Ty, Q, RecursionLimit);
3899 }
3900 
3901 /// For the given destination element of a shuffle, peek through shuffles to
3902 /// match a root vector source operand that contains that element in the same
3903 /// vector lane (ie, the same mask index), so we can eliminate the shuffle(s).
3904 static Value *foldIdentityShuffles(int DestElt, Value *Op0, Value *Op1,
3905  int MaskVal, Value *RootVec,
3906  unsigned MaxRecurse) {
3907  if (!MaxRecurse--)
3908  return nullptr;
3909 
3910  // Bail out if any mask value is undefined. That kind of shuffle may be
3911  // simplified further based on demanded bits or other folds.
3912  if (MaskVal == -1)
3913  return nullptr;
3914 
3915  // The mask value chooses which source operand we need to look at next.
3916  int InVecNumElts = Op0->getType()->getVectorNumElements();
3917  int RootElt = MaskVal;
3918  Value *SourceOp = Op0;
3919  if (MaskVal >= InVecNumElts) {
3920  RootElt = MaskVal - InVecNumElts;
3921  SourceOp = Op1;
3922  }
3923 
3924  // If the source operand is a shuffle itself, look through it to find the
3925  // matching root vector.
3926  if (auto *SourceShuf = dyn_cast<ShuffleVectorInst>(SourceOp)) {
3927  return foldIdentityShuffles(
3928  DestElt, SourceShuf->getOperand(0), SourceShuf->getOperand(1),
3929  SourceShuf->getMaskValue(RootElt), RootVec, MaxRecurse);
3930  }
3931 
3932  // TODO: Look through bitcasts? What if the bitcast changes the vector element
3933  // size?
3934 
3935  // The source operand is not a shuffle. Initialize the root vector value for
3936  // this shuffle if that has not been done yet.
3937  if (!RootVec)
3938  RootVec = SourceOp;
3939 
3940  // Give up as soon as a source operand does not match the existing root value.
3941  if (RootVec != SourceOp)
3942  return nullptr;
3943 
3944  // The element must be coming from the same lane in the source vector
3945  // (although it may have crossed lanes in intermediate shuffles).
3946  if (RootElt != DestElt)
3947  return nullptr;
3948 
3949  return RootVec;
3950 }
3951 
3953  Type *RetTy, const SimplifyQuery &Q,
3954  unsigned MaxRecurse) {
3955  if (isa<UndefValue>(Mask))
3956  return UndefValue::get(RetTy);
3957 
3958  Type *InVecTy = Op0->getType();
3959  unsigned MaskNumElts = Mask->getType()->getVectorNumElements();
3960  unsigned InVecNumElts = InVecTy->getVectorNumElements();
3961 
3962  SmallVector<int, 32> Indices;
3963  ShuffleVectorInst::getShuffleMask(Mask, Indices);
3964  assert(MaskNumElts == Indices.size() &&
3965  "Size of Indices not same as number of mask elements?");
3966 
3967  // Canonicalization: If mask does not select elements from an input vector,
3968  // replace that input vector with undef.
3969  bool MaskSelects0 = false, MaskSelects1 = false;
3970  for (unsigned i = 0; i != MaskNumElts; ++i) {
3971  if (Indices[i] == -1)
3972  continue;
3973  if ((unsigned)Indices[i] < InVecNumElts)
3974  MaskSelects0 = true;
3975  else
3976  MaskSelects1 = true;
3977  }
3978  if (!MaskSelects0)
3979  Op0 = UndefValue::get(InVecTy);
3980  if (!MaskSelects1)
3981  Op1 = UndefValue::get(InVecTy);
3982 
3983  auto *Op0Const = dyn_cast<Constant>(Op0);
3984  auto *Op1Const = dyn_cast<Constant>(Op1);
3985 
3986  // If all operands are constant, constant fold the shuffle.
3987  if (Op0Const && Op1Const)
3988  return ConstantFoldShuffleVectorInstruction(Op0Const, Op1Const, Mask);
3989 
3990  // Canonicalization: if only one input vector is constant, it shall be the
3991  // second one.
3992  if (Op0Const && !Op1Const) {
3993  std::swap(Op0, Op1);
3994  ShuffleVectorInst::commuteShuffleMask(Indices, InVecNumElts);
3995  }
3996 
3997  // A shuffle of a splat is always the splat itself. Legal if the shuffle's
3998  // value type is same as the input vectors' type.
3999  if (auto *OpShuf = dyn_cast<ShuffleVectorInst>(Op0))
4000  if (isa<UndefValue>(Op1) && RetTy == InVecTy &&
4001  OpShuf->getMask()->getSplatValue())
4002  return Op0;
4003 
4004  // Don't fold a shuffle with undef mask elements. This may get folded in a
4005  // better way using demanded bits or other analysis.
4006  // TODO: Should we allow this?
4007  if (find(Indices, -1) != Indices.end())
4008  return nullptr;
4009 
4010  // Check if every element of this shuffle can be mapped back to the
4011  // corresponding element of a single root vector. If so, we don't need this
4012  // shuffle. This handles simple identity shuffles as well as chains of
4013  // shuffles that may widen/narrow and/or move elements across lanes and back.
4014  Value *RootVec = nullptr;
4015  for (unsigned i = 0; i != MaskNumElts; ++i) {
4016  // Note that recursion is limited for each vector element, so if any element
4017  // exceeds the limit, this will fail to simplify.
4018  RootVec =
4019  foldIdentityShuffles(i, Op0, Op1, Indices[i], RootVec, MaxRecurse);
4020 
4021  // We can't replace a widening/narrowing shuffle with one of its operands.
4022  if (!RootVec || RootVec->getType() != RetTy)
4023  return nullptr;
4024  }
4025  return RootVec;
4026 }
4027 
4028 /// Given operands for a ShuffleVectorInst, fold the result or return null.
4030  Type *RetTy, const SimplifyQuery &Q) {
4031  return ::SimplifyShuffleVectorInst(Op0, Op1, Mask, RetTy, Q, RecursionLimit);
4032 }
4033 
4034 /// Given operands for an FAdd, see if we can fold the result. If not, this
4035 /// returns null.
4037  const SimplifyQuery &Q, unsigned MaxRecurse) {
4038  if (Constant *C = foldOrCommuteConstant(Instruction::FAdd, Op0, Op1, Q))
4039  return C;
4040 
4041  // fadd X, -0 ==> X
4042  if (match(Op1, m_NegZero()))
4043  return Op0;
4044 
4045  // fadd X, 0 ==> X, when we know X is not -0
4046  if (match(Op1, m_Zero()) &&
4047  (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
4048  return Op0;
4049 
4050  // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
4051  // where nnan and ninf have to occur at least once somewhere in this
4052  // expression
4053  Value *SubOp = nullptr;
4054  if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
4055  SubOp = Op1;
4056  else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
4057  SubOp = Op0;
4058  if (SubOp) {
4059  Instruction *FSub = cast<Instruction>(SubOp);
4060  if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
4061  (FMF.noInfs() || FSub->hasNoInfs()))
4062  return Constant::getNullValue(Op0->getType());
4063  }
4064 
4065  return nullptr;
4066 }
4067 
4068 /// Given operands for an FSub, see if we can fold the result. If not, this
4069 /// returns null.
4071  const SimplifyQuery &Q, unsigned MaxRecurse) {
4072  if (Constant *C = foldOrCommuteConstant(Instruction::FSub, Op0, Op1, Q))
4073  return C;
4074 
4075  // fsub X, 0 ==> X
4076  if (match(Op1, m_Zero()))
4077  return Op0;
4078 
4079  // fsub X, -0 ==> X, when we know X is not -0
4080  if (match(Op1, m_NegZero()) &&
4081  (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
4082  return Op0;
4083 
4084  // fsub -0.0, (fsub -0.0, X) ==> X
4085  Value *X;
4086  if (match(Op0, m_NegZero()) && match(Op1, m_FSub(m_NegZero(), m_Value(X))))
4087  return X;
4088 
4089  // fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored.
4090  if (FMF.noSignedZeros() && match(Op0, m_AnyZero()) &&
4091  match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
4092  return X;
4093 
4094  // fsub nnan x, x ==> 0.0
4095  if (FMF.noNaNs() && Op0 == Op1)
4096  return Constant::getNullValue(Op0->getType());
4097 
4098  return nullptr;
4099 }
4100 
4101 /// Given the operands for an FMul, see if we can fold the result
4103  const SimplifyQuery &Q, unsigned MaxRecurse) {
4104  if (Constant *C = foldOrCommuteConstant(Instruction::FMul, Op0, Op1, Q))
4105  return C;
4106 
4107  // fmul X, 1.0 ==> X
4108  if (match(Op1, m_FPOne()))
4109  return Op0;
4110 
4111  // fmul nnan nsz X, 0 ==> 0
4112  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
4113  return Op1;
4114 
4115  return nullptr;
4116 }
4117 
4119  const SimplifyQuery &Q) {
4120  return ::SimplifyFAddInst(Op0, Op1, FMF, Q, RecursionLimit);
4121 }
4122 
4123 
4125  const SimplifyQuery &Q) {
4126  return ::SimplifyFSubInst(Op0, Op1, FMF, Q, RecursionLimit);
4127 }
4128 
4130  const SimplifyQuery &Q) {
4131  return ::SimplifyFMulInst(Op0, Op1, FMF, Q, RecursionLimit);
4132 }
4133 
4135  const SimplifyQuery &Q, unsigned) {
4136  if (Constant *C = foldOrCommuteConstant(Instruction::FDiv, Op0, Op1, Q))
4137  return C;
4138 
4139  // undef / X -> undef (the undef could be a snan).
4140  if (match(Op0, m_Undef()))
4141  return Op0;
4142 
4143  // X / undef -> undef
4144  if (match(Op1, m_Undef()))
4145  return Op1;
4146 
4147  // X / 1.0 -> X
4148  if (match(Op1, m_FPOne()))
4149  return Op0;
4150 
4151  // 0 / X -> 0
4152  // Requires that NaNs are off (X could be zero) and signed zeroes are
4153  // ignored (X could be positive or negative, so the output sign is unknown).
4154  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZero()))
4155  return Op0;
4156 
4157  if (FMF.noNaNs()) {
4158  // X / X -> 1.0 is legal when NaNs are ignored.
4159  if (Op0 == Op1)
4160  return ConstantFP::get(Op0->getType(), 1.0);
4161 
4162  // -X / X -> -1.0 and
4163  // X / -X -> -1.0 are legal when NaNs are ignored.
4164  // We can ignore signed zeros because +-0.0/+-0.0 is NaN and ignored.
4165  if ((BinaryOperator::isFNeg(Op0, /*IgnoreZeroSign=*/true) &&
4166  BinaryOperator::getFNegArgument(Op0) == Op1) ||
4167  (BinaryOperator::isFNeg(Op1, /*IgnoreZeroSign=*/true) &&
4168  BinaryOperator::getFNegArgument(Op1) == Op0))
4169  return ConstantFP::get(Op0->getType(), -1.0);
4170  }
4171 
4172  return nullptr;
4173 }
4174 
4176  const SimplifyQuery &Q) {
4177  return ::SimplifyFDivInst(Op0, Op1, FMF, Q, RecursionLimit);
4178 }
4179 
4181  const SimplifyQuery &Q, unsigned) {
4182  if (Constant *C = foldOrCommuteConstant(Instruction::FRem, Op0, Op1, Q))
4183  return C;
4184 
4185  // undef % X -> undef (the undef could be a snan).
4186  if (match(Op0, m_Undef()))
4187  return Op0;
4188 
4189  // X % undef -> undef
4190  if (match(Op1, m_Undef()))
4191  return Op1;
4192 
4193  // 0 % X -> 0
4194  // Requires that NaNs are off (X could be zero) and signed zeroes are
4195  // ignored (X could be positive or negative, so the output sign is unknown).
4196  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZero()))
4197  return Op0;
4198 
4199  return nullptr;
4200 }
4201 
4203  const SimplifyQuery &Q) {
4204  return ::SimplifyFRemInst(Op0, Op1, FMF, Q, RecursionLimit);
4205 }
4206 
4207 //=== Helper functions for higher up the class hierarchy.
4208 
4209 /// Given operands for a BinaryOperator, see if we can fold the result.
4210 /// If not, this returns null.
4211 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4212  const SimplifyQuery &Q, unsigned MaxRecurse) {
4213  switch (Opcode) {
4214  case Instruction::Add:
4215  return SimplifyAddInst(LHS, RHS, false, false, Q, MaxRecurse);
4216  case Instruction::Sub:
4217  return SimplifySubInst(LHS, RHS, false, false, Q, MaxRecurse);
4218  case Instruction::Mul:
4219  return SimplifyMulInst(LHS, RHS, Q, MaxRecurse);
4220  case Instruction::SDiv:
4221  return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
4222  case Instruction::UDiv:
4223  return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
4224  case Instruction::SRem:
4225  return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
4226  case Instruction::URem:
4227  return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
4228  case Instruction::Shl:
4229  return SimplifyShlInst(LHS, RHS, false, false, Q, MaxRecurse);
4230  case Instruction::LShr:
4231  return SimplifyLShrInst(LHS, RHS, false, Q, MaxRecurse);
4232  case Instruction::AShr:
4233  return SimplifyAShrInst(LHS, RHS, false, Q, MaxRecurse);
4234  case Instruction::And:
4235  return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
4236  case Instruction::Or:
4237  return SimplifyOrInst(LHS, RHS, Q, MaxRecurse);
4238  case Instruction::Xor:
4239  return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
4240  case Instruction::FAdd:
4241  return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4242  case Instruction::FSub:
4243  return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4244  case Instruction::FMul:
4245  return SimplifyFMulInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4246  case Instruction::FDiv:
4247  return SimplifyFDivInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4248  case Instruction::FRem:
4249  return SimplifyFRemInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4250  default:
4251  llvm_unreachable("Unexpected opcode");
4252  }
4253 }
4254 
4255 /// Given operands for a BinaryOperator, see if we can fold the result.
4256 /// If not, this returns null.
4257 /// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the
4258 /// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp.
4259 static Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4260  const FastMathFlags &FMF, const SimplifyQuery &Q,
4261  unsigned MaxRecurse) {
4262  switch (Opcode) {
4263  case Instruction::FAdd:
4264  return SimplifyFAddInst(LHS, RHS, FMF, Q, MaxRecurse);
4265  case Instruction::FSub:
4266  return SimplifyFSubInst(LHS, RHS, FMF, Q, MaxRecurse);
4267  case Instruction::FMul:
4268  return SimplifyFMulInst(LHS, RHS, FMF, Q, MaxRecurse);
4269  case Instruction::FDiv:
4270  return SimplifyFDivInst(LHS, RHS, FMF, Q, MaxRecurse);
4271  default:
4272  return SimplifyBinOp(Opcode, LHS, RHS, Q, MaxRecurse);
4273  }
4274 }
4275 
4276 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4277  const SimplifyQuery &Q) {
4278  return ::SimplifyBinOp(Opcode, LHS, RHS, Q, RecursionLimit);
4279 }
4280 
4281 Value *llvm::SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4282  FastMathFlags FMF, const SimplifyQuery &Q) {
4283  return ::SimplifyFPBinOp(Opcode, LHS, RHS, FMF, Q, RecursionLimit);
4284 }
4285 
4286 /// Given operands for a CmpInst, see if we can fold the result.
4287 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
4288  const SimplifyQuery &Q, unsigned MaxRecurse) {
4290  return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
4291  return SimplifyFCmpInst(Predicate, LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4292 }
4293 
4294 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
4295  const SimplifyQuery &Q) {
4296  return ::SimplifyCmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
4297 }
4298 
4300  switch (ID) {
4301  default: return false;
4302 
4303  // Unary idempotent: f(f(x)) = f(x)
4304  case Intrinsic::fabs:
4305  case Intrinsic::floor:
4306  case Intrinsic::ceil:
4307  case Intrinsic::trunc:
4308  case Intrinsic::rint:
4309  case Intrinsic::nearbyint:
4310  case Intrinsic::round:
4311  case Intrinsic::canonicalize:
4312  return true;
4313  }
4314 }
4315 
4317  const DataLayout &DL) {
4318  GlobalValue *PtrSym;
4319  APInt PtrOffset;
4320  if (!IsConstantOffsetFromGlobal(Ptr, PtrSym, PtrOffset, DL))
4321  return nullptr;
4322 
4323  Type *Int8PtrTy = Type::getInt8PtrTy(Ptr->getContext());
4325  Type *Int32PtrTy = Int32Ty->getPointerTo();
4326  Type *Int64Ty = Type::getInt64Ty(Ptr->getContext());
4327 
4328  auto *OffsetConstInt = dyn_cast<ConstantInt>(Offset);
4329  if (!OffsetConstInt || OffsetConstInt->getType()->getBitWidth() > 64)
4330  return nullptr;
4331 
4332  uint64_t OffsetInt = OffsetConstInt->getSExtValue();
4333  if (OffsetInt % 4 != 0)
4334  return nullptr;
4335 
4337  Int32Ty, ConstantExpr::getBitCast(Ptr, Int32PtrTy),
4338  ConstantInt::get(Int64Ty, OffsetInt / 4));
4339  Constant *Loaded = ConstantFoldLoadFromConstPtr(C, Int32Ty, DL);
4340  if (!Loaded)
4341  return nullptr;
4342 
4343  auto *LoadedCE = dyn_cast<ConstantExpr>(Loaded);
4344  if (!LoadedCE)
4345  return nullptr;
4346 
4347  if (LoadedCE->getOpcode() == Instruction::Trunc) {
4348  LoadedCE = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4349  if (!LoadedCE)
4350  return nullptr;
4351  }
4352 
4353  if (LoadedCE->getOpcode() != Instruction::Sub)
4354  return nullptr;
4355 
4356  auto *LoadedLHS = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4357  if (!LoadedLHS || LoadedLHS->getOpcode() != Instruction::PtrToInt)
4358  return nullptr;
4359  auto *LoadedLHSPtr = LoadedLHS->getOperand(0);
4360 
4361  Constant *LoadedRHS = LoadedCE->getOperand(1);
4362  GlobalValue *LoadedRHSSym;
4363  APInt LoadedRHSOffset;
4364  if (!IsConstantOffsetFromGlobal(LoadedRHS, LoadedRHSSym, LoadedRHSOffset,
4365  DL) ||
4366  PtrSym != LoadedRHSSym || PtrOffset != LoadedRHSOffset)
4367  return nullptr;
4368 
4369  return ConstantExpr::getBitCast(LoadedLHSPtr, Int8PtrTy);
4370 }
4371 
4373  auto *ConstMask = dyn_cast<Constant>(Mask);
4374  if (!ConstMask)
4375  return false;
4376  if (ConstMask->isNullValue() || isa<UndefValue>(ConstMask))
4377  return true;
4378  for (unsigned I = 0, E = ConstMask->getType()->getVectorNumElements(); I != E;
4379  ++I) {
4380  if (auto *MaskElt = ConstMask->getAggregateElement(I))
4381  if (MaskElt->isNullValue() || isa<UndefValue>(MaskElt))
4382  continue;
4383  return false;
4384  }
4385  return true;
4386 }
4387 
4388 template <typename IterTy>
4389 static Value *SimplifyIntrinsic(Function *F, IterTy ArgBegin, IterTy ArgEnd,
4390  const SimplifyQuery &Q, unsigned MaxRecurse) {
4391  Intrinsic::ID IID = F->getIntrinsicID();
4392  unsigned NumOperands = std::distance(ArgBegin, ArgEnd);
4393 
4394  // Unary Ops
4395  if (NumOperands == 1) {
4396  // Perform idempotent optimizations
4397  if (IsIdempotent(IID)) {
4398  if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin)) {
4399  if (II->getIntrinsicID() == IID)
4400  return II;
4401  }
4402  }
4403 
4404  switch (IID) {
4405  case Intrinsic::fabs: {
4406  if (SignBitMustBeZero(*ArgBegin, Q.TLI))
4407  return *ArgBegin;
4408  return nullptr;
4409  }
4410  default:
4411  return nullptr;
4412  }
4413  }
4414 
4415  // Binary Ops
4416  if (NumOperands == 2) {
4417  Value *LHS = *ArgBegin;
4418  Value *RHS = *(ArgBegin + 1);
4419  Type *ReturnType = F->getReturnType();
4420 
4421  switch (IID) {
4422  case Intrinsic::usub_with_overflow:
4423  case Intrinsic::ssub_with_overflow: {
4424  // X - X -> { 0, false }
4425  if (LHS == RHS)
4426  return Constant::getNullValue(ReturnType);
4427 
4428  // X - undef -> undef
4429  // undef - X -> undef
4430  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
4431  return UndefValue::get(ReturnType);
4432 
4433  return nullptr;
4434  }
4435  case Intrinsic::uadd_with_overflow:
4436  case Intrinsic::sadd_with_overflow: {
4437  // X + undef -> undef
4438  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
4439  return UndefValue::get(ReturnType);
4440 
4441  return nullptr;
4442  }
4443  case Intrinsic::umul_with_overflow:
4444  case Intrinsic::smul_with_overflow: {
4445  // 0 * X -> { 0, false }
4446  // X * 0 -> { 0, false }
4447  if (match(LHS, m_Zero()) || match(RHS, m_Zero()))
4448  return Constant::getNullValue(ReturnType);
4449 
4450  // undef * X -> { 0, false }
4451  // X * undef -> { 0, false }
4452  if (match(LHS, m_Undef()) || match(RHS, m_Undef()))
4453  return Constant::getNullValue(ReturnType);
4454 
4455  return nullptr;
4456  }
4457  case Intrinsic::load_relative: {
4458  Constant *C0 = dyn_cast<Constant>(LHS);
4459  Constant *C1 = dyn_cast<Constant>(RHS);
4460  if (C0 && C1)
4461  return SimplifyRelativeLoad(C0, C1, Q.DL);
4462  return nullptr;
4463  }
4464  default:
4465  return nullptr;
4466  }
4467  }
4468 
4469  // Simplify calls to llvm.masked.load.*
4470  switch (IID) {
4471  case Intrinsic::masked_load: {
4472  Value *MaskArg = ArgBegin[2];
4473  Value *PassthruArg = ArgBegin[3];
4474  // If the mask is all zeros or undef, the "passthru" argument is the result.
4475  if (maskIsAllZeroOrUndef(MaskArg))
4476  return PassthruArg;
4477  return nullptr;
4478  }
4479  default:
4480  return nullptr;
4481  }
4482 }
4483 
4484 template <typename IterTy>
4485 static Value *SimplifyCall(ImmutableCallSite CS, Value *V, IterTy ArgBegin,
4486  IterTy ArgEnd, const SimplifyQuery &Q,
4487  unsigned MaxRecurse) {
4488  Type *Ty = V->getType();
4489  if (PointerType *PTy = dyn_cast<PointerType>(Ty))
4490  Ty = PTy->getElementType();
4491  FunctionType *FTy = cast<FunctionType>(Ty);
4492 
4493  // call undef -> undef
4494  // call null -> undef
4495  if (isa<UndefValue>(V) || isa<ConstantPointerNull>(V))
4496  return UndefValue::get(FTy->getReturnType());
4497 
4498  Function *F = dyn_cast<Function>(V);
4499  if (!F)
4500  return nullptr;
4501 
4502  if (F->isIntrinsic())
4503  if (Value *Ret = SimplifyIntrinsic(F, ArgBegin, ArgEnd, Q, MaxRecurse))
4504  return Ret;
4505 
4506  if (!canConstantFoldCallTo(CS, F))
4507  return nullptr;
4508 
4509  SmallVector<Constant *, 4> ConstantArgs;
4510  ConstantArgs.reserve(ArgEnd - ArgBegin);
4511  for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
4512  Constant *C = dyn_cast<Constant>(*I);
4513  if (!C)
4514  return nullptr;
4515  ConstantArgs.push_back(C);
4516  }
4517 
4518  return ConstantFoldCall(CS, F, ConstantArgs, Q.TLI);
4519 }
4520 
4522  User::op_iterator ArgBegin, User::op_iterator ArgEnd,
4523  const SimplifyQuery &Q) {
4524  return ::SimplifyCall(CS, V, ArgBegin, ArgEnd, Q, RecursionLimit);
4525 }
4526 
4528  ArrayRef<Value *> Args, const SimplifyQuery &Q) {
4529  return ::SimplifyCall(CS, V, Args.begin(), Args.end(), Q, RecursionLimit);
4530 }
4531 
4532 /// See if we can compute a simplified version of this instruction.
4533 /// If not, this returns null.
4534 
4537  const SimplifyQuery Q = SQ.CxtI ? SQ : SQ.getWithInstruction(I);
4538  Value *Result;
4539 
4540  switch (I->getOpcode()) {
4541  default:
4542  Result = ConstantFoldInstruction(I, Q.DL, Q.TLI);
4543  break;
4544  case Instruction::FAdd:
4545  Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
4546  I->getFastMathFlags(), Q);
4547  break;
4548  case Instruction::Add:
4549  Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
4550  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4551  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4552  break;
4553  case Instruction::FSub:
4554  Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
4555  I->getFastMathFlags(), Q);
4556  break;
4557  case Instruction::Sub:
4558  Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
4559  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4560  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4561  break;
4562  case Instruction::FMul:
4563  Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
4564  I->getFastMathFlags(), Q);
4565  break;
4566  case Instruction::Mul:
4567  Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), Q);
4568  break;
4569  case Instruction::SDiv:
4570  Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), Q);
4571  break;
4572  case Instruction::UDiv:
4573  Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), Q);
4574  break;
4575  case Instruction::FDiv:
4576  Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1),
4577  I->getFastMathFlags(), Q);
4578  break;
4579  case Instruction::SRem:
4580  Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), Q);
4581  break;
4582  case Instruction::URem:
4583  Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), Q);
4584  break;
4585  case Instruction::FRem:
4586  Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1),
4587  I->getFastMathFlags(), Q);
4588  break;
4589  case Instruction::Shl:
4590  Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
4591  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4592  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4593  break;
4594  case Instruction::LShr:
4595  Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
4596  cast<BinaryOperator>(I)->isExact(), Q);
4597  break;
4598  case Instruction::AShr:
4599  Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
4600  cast<BinaryOperator>(I)->isExact(), Q);
4601  break;
4602  case Instruction::And:
4603  Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), Q);
4604  break;
4605  case Instruction::Or:
4606  Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), Q);
4607  break;
4608  case Instruction::Xor:
4609  Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), Q);
4610  break;
4611  case Instruction::ICmp:
4612  Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
4613  I->getOperand(0), I->getOperand(1), Q);
4614  break;
4615  case Instruction::FCmp:
4616  Result =
4617  SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(), I->getOperand(0),
4618  I->getOperand(1), I->getFastMathFlags(), Q);
4619  break;
4620  case Instruction::Select:
4621  Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
4622  I->getOperand(2), Q);
4623  break;
4624  case Instruction::GetElementPtr: {
4625  SmallVector<Value *, 8> Ops(I->op_begin(), I->op_end());
4626  Result = SimplifyGEPInst(cast<GetElementPtrInst>(I)->getSourceElementType(),
4627  Ops, Q);
4628  break;
4629  }
4630  case Instruction::InsertValue: {
4631  InsertValueInst *IV = cast<InsertValueInst>(I);
4634  IV->getIndices(), Q);
4635  break;
4636  }
4637  case Instruction::ExtractValue: {
4638  auto *EVI = cast<ExtractValueInst>(I);
4639  Result = SimplifyExtractValueInst(EVI->getAggregateOperand(),
4640  EVI->getIndices(), Q);
4641  break;
4642  }
4643  case Instruction::ExtractElement: {
4644  auto *EEI = cast<ExtractElementInst>(I);
4645  Result = SimplifyExtractElementInst(EEI->getVectorOperand(),
4646  EEI->getIndexOperand(), Q);
4647  break;
4648  }
4649  case Instruction::ShuffleVector: {
4650  auto *SVI = cast<ShuffleVectorInst>(I);
4651  Result = SimplifyShuffleVectorInst(SVI->getOperand(0), SVI->getOperand(1),
4652  SVI->getMask(), SVI->getType(), Q);
4653  break;
4654  }
4655  case Instruction::PHI:
4656  Result = SimplifyPHINode(cast<PHINode>(I), Q);
4657  break;
4658  case Instruction::Call: {
4659  CallSite CS(cast<CallInst>(I));
4660  Result = SimplifyCall(CS, CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
4661  Q);
4662  break;
4663  }
4664 #define HANDLE_CAST_INST(num, opc, clas) case Instruction::opc:
4665 #include "llvm/IR/Instruction.def"
4666 #undef HANDLE_CAST_INST
4667  Result =
4668  SimplifyCastInst(I->getOpcode(), I->getOperand(0), I->getType(), Q);
4669  break;
4670  case Instruction::Alloca:
4671  // No simplifications for Alloca and it can't be constant folded.
4672  Result = nullptr;
4673  break;
4674  }
4675 
4676  // In general, it is possible for computeKnownBits to determine all bits in a
4677  // value even when the operands are not all constants.
4678  if (!Result && I->getType()->isIntOrIntVectorTy()) {
4679  KnownBits Known = computeKnownBits(I, Q.DL, /*Depth*/ 0, Q.AC, I, Q.DT, ORE);
4680  if (Known.isConstant())
4681  Result = ConstantInt::get(I->getType(), Known.getConstant());
4682  }
4683 
4684  /// If called on unreachable code, the above logic may report that the
4685  /// instruction simplified to itself. Make life easier for users by
4686  /// detecting that case here, returning a safe value instead.
4687  return Result == I ? UndefValue::get(I->getType()) : Result;
4688 }
4689 
4690 /// \brief Implementation of recursive simplification through an instruction's
4691 /// uses.
4692 ///
4693 /// This is the common implementation of the recursive simplification routines.
4694 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
4695 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
4696 /// instructions to process and attempt to simplify it using
4697 /// InstructionSimplify.
4698 ///
4699 /// This routine returns 'true' only when *it* simplifies something. The passed
4700 /// in simplified value does not count toward this.
4702  const TargetLibraryInfo *TLI,
4703  const DominatorTree *DT,
4704  AssumptionCache *AC) {
4705  bool Simplified = false;
4707  const DataLayout &DL = I->getModule()->getDataLayout();
4708 
4709  // If we have an explicit value to collapse to, do that round of the
4710  // simplification loop by hand initially.
4711  if (SimpleV) {
4712  for (User *U : I->users())
4713  if (U != I)
4714  Worklist.insert(cast<Instruction>(U));
4715 
4716  // Replace the instruction with its simplified value.
4717  I->replaceAllUsesWith(SimpleV);
4718 
4719  // Gracefully handle edge cases where the instruction is not wired into any
4720  // parent block.
4721  if (I->getParent() && !I->isEHPad() && !isa<TerminatorInst>(I) &&
4722  !I->mayHaveSideEffects())
4723  I->eraseFromParent();
4724  } else {
4725  Worklist.insert(I);
4726  }
4727 
4728  // Note that we must test the size on each iteration, the worklist can grow.
4729  for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
4730  I = Worklist[Idx];
4731 
4732  // See if this instruction simplifies.
4733  SimpleV = SimplifyInstruction(I, {DL, TLI, DT, AC});
4734  if (!SimpleV)
4735  continue;
4736 
4737  Simplified = true;
4738 
4739  // Stash away all the uses of the old instruction so we can check them for
4740  // recursive simplifications after a RAUW. This is cheaper than checking all
4741  // uses of To on the recursive step in most cases.
4742  for (User *U : I->users())
4743  Worklist.insert(cast<Instruction>(U));
4744 
4745  // Replace the instruction with its simplified value.
4746  I->replaceAllUsesWith(SimpleV);
4747 
4748  // Gracefully handle edge cases where the instruction is not wired into any
4749  // parent block.
4750  if (I->getParent() && !I->isEHPad() && !isa<TerminatorInst>(I) &&
4751  !I->mayHaveSideEffects())
4752  I->eraseFromParent();
4753  }
4754  return Simplified;
4755 }
4756 
4758  const TargetLibraryInfo *TLI,
4759  const DominatorTree *DT,
4760  AssumptionCache *AC) {
4761  return replaceAndRecursivelySimplifyImpl(I, nullptr, TLI, DT, AC);
4762 }
4763 
4765  const TargetLibraryInfo *TLI,
4766  const DominatorTree *DT,
4767  AssumptionCache *AC) {
4768  assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
4769  assert(SimpleV && "Must provide a simplified value.");
4770  return replaceAndRecursivelySimplifyImpl(I, SimpleV, TLI, DT, AC);
4771 }
4772 
4773 namespace llvm {
4776  auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
4778  auto *TLI = TLIWP ? &TLIWP->getTLI() : nullptr;
4780  auto *AC = ACWP ? &ACWP->getAssumptionCache(F) : nullptr;
4781  return {F.getParent()->getDataLayout(), TLI, DT, AC};
4782 }
4783 
4785  const DataLayout &DL) {
4786  return {DL, &AR.TLI, &AR.DT, &AR.AC};
4787 }
4788 
4789 template <class T, class... TArgs>
4791  Function &F) {
4792  auto *DT = AM.template getCachedResult<DominatorTreeAnalysis>(F);
4793  auto *TLI = AM.template getCachedResult<TargetLibraryAnalysis>(F);
4794  auto *AC = AM.template getCachedResult<AssumptionAnalysis>(F);
4795  return {F.getParent()->getDataLayout(), TLI, DT, AC};
4796 }
4798  Function &);
4799 }
Constant * ConstantFoldCastOperand(unsigned Opcode, Constant *C, Type *DestTy, const DataLayout &DL)
Attempt to constant fold a cast with the specified operand.
static Value * SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse)
Given operands for a URem, see if we can fold the result.
MaxMin_match< ICmpInst, LHS, RHS, umin_pred_ty > m_UMin(const LHS &L, const RHS &R)
APInt abs() const
Get the absolute value;.
Definition: APInt.h:1779
Pass interface - Implemented by all &#39;passes&#39;.
Definition: Pass.h:81
bool getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout &DL, const TargetLibraryInfo *TLI, ObjectSizeOpts Opts={})
Compute the size of the object pointed by Ptr.
bool isFPPredicate() const
Definition: InstrTypes.h:951
Type * getVectorElementType() const
Definition: Type.h:368
BinaryOp_match< LHS, RHS, Instruction::And > m_And(const LHS &L, const RHS &R)
Definition: PatternMatch.h:574
uint64_t CallInst * C
Value * SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, const SimplifyQuery &Q)
Given operands for an ICmpInst, fold the result or return null.
static Value * SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, const SimplifyQuery &Q, unsigned MaxRecurse)
Given operands for an AShr, see if we can fold the result.
BinOpPred_match< LHS, RHS, is_right_shift_op > m_Shr(const LHS &L, const RHS &R)
Matches logical shift operations.
Definition: PatternMatch.h:758
SymbolTableList< Instruction >::iterator eraseFromParent()
This method unlinks &#39;this&#39; from the containing basic block and deletes it.
Definition: Instruction.cpp:69
bool hasNoInfs() const
Determine whether the no-infs flag is set.
unsigned Log2_32_Ceil(uint32_t Value)
Return the ceil log base 2 of the specified value, 32 if the value is zero.
Definition: MathExtras.h:544
A parsed version of the target data layout string in and methods for querying it. ...
Definition: DataLayout.h:109
static ConstantInt * getFalse(LLVMContext &Context)
Definition: Constants.cpp:523
bool isKnownToBeAPowerOfTwo(const Value *V, const DataLayout &DL, bool OrZero=false, unsigned Depth=0, AssumptionCache *AC=nullptr, const Instruction *CxtI=nullptr, const DominatorTree *DT=nullptr)
Return true if the given value is known to have exactly one bit set when defined. ...
class_match< Value > m_Value()
Match an arbitrary value and ignore it.
Definition: PatternMatch.h:72
This class is the base class for the comparison instructions.
Definition: InstrTypes.h:850
class_match< UndefValue > m_Undef()
Match an arbitrary undef constant.
Definition: PatternMatch.h:88
static GCMetadataPrinterRegistry::Add< ErlangGCPrinter > X("erlang", "erlang-compatible garbage collector")
static Value * SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse)
Given operands for an SRem, see if we can fold the result.
bool isSignMask() const
Check if the APInt&#39;s value is returned by getSignMask.
Definition: APInt.h:466
bool isZero() const
Definition: APFloat.h:1128
bool isAllOnesValue() const
Return true if this is the value that would be returned by getAllOnesValue.
Definition: Constants.cpp:101
This instruction extracts a struct member or array element value from an aggregate value...
static Value * SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse)
Given operands for a Mul, see if we can fold the result.
static APInt getAllOnesValue(unsigned numBits)
Get the all-ones value.
Definition: APInt.h:555
This class represents an incoming formal argument to a Function.
Definition: Argument.h:30
const T & back() const
back - Get the last element.
Definition: ArrayRef.h:158
BinaryOp_match< LHS, RHS, Instruction::Sub > m_Sub(const LHS &L, const RHS &R)
Definition: PatternMatch.h:514
bool noNaNs() const
Flag queries.
Definition: Operator.h:189
Value * getAggregateOperand()
Value * SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, FastMathFlags FMF, const SimplifyQuery &Q)
Given operands for an FCmpInst, fold the result or return null.
static const Value * getFNegArgument(const Value *BinOp)
static bool isDivZero(Value *X, Value *Y, const SimplifyQuery &Q, unsigned MaxRecurse, bool IsSigned)
Return true if we can simplify X / Y to 0.
static Type * makeCmpResultType(Type *opnd_type)
Create a result type for fcmp/icmp.
Definition: InstrTypes.h:1074
Value * findScalarElement(Value *V, unsigned EltNo)
Given a vector and an element number, see if the scalar value is already around as a register...
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
SimplifyQuery getWithInstruction(Instruction *I) const
BinaryOps getOpcode() const
Definition: InstrTypes.h:523
BinaryOp_match< LHS, RHS, Instruction::Xor, true > m_c_Xor(const LHS &L, const RHS &R)
Matches an Xor with LHS and RHS in either order.