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 *simplifyAndOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS, bool IsAnd) {
1554  Value *LHS0 = LHS->getOperand(0), *LHS1 = LHS->getOperand(1);
1555  Value *RHS0 = RHS->getOperand(0), *RHS1 = RHS->getOperand(1);
1556  if (LHS0->getType() != RHS0->getType())
1557  return nullptr;
1558 
1559  FCmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
1560  if ((PredL == FCmpInst::FCMP_ORD && PredR == FCmpInst::FCMP_ORD && IsAnd) ||
1561  (PredL == FCmpInst::FCMP_UNO && PredR == FCmpInst::FCMP_UNO && !IsAnd)) {
1562  // (fcmp ord NNAN, X) & (fcmp ord X, Y) --> fcmp ord X, Y
1563  // (fcmp ord NNAN, X) & (fcmp ord Y, X) --> fcmp ord Y, X
1564  // (fcmp ord X, NNAN) & (fcmp ord X, Y) --> fcmp ord X, Y
1565  // (fcmp ord X, NNAN) & (fcmp ord Y, X) --> fcmp ord Y, X
1566  // (fcmp uno NNAN, X) | (fcmp uno X, Y) --> fcmp uno X, Y
1567  // (fcmp uno NNAN, X) | (fcmp uno Y, X) --> fcmp uno Y, X
1568  // (fcmp uno X, NNAN) | (fcmp uno X, Y) --> fcmp uno X, Y
1569  // (fcmp uno X, NNAN) | (fcmp uno Y, X) --> fcmp uno Y, X
1570  if ((isKnownNeverNaN(LHS0) && (LHS1 == RHS0 || LHS1 == RHS1)) ||
1571  (isKnownNeverNaN(LHS1) && (LHS0 == RHS0 || LHS0 == RHS1)))
1572  return RHS;
1573 
1574  // (fcmp ord X, Y) & (fcmp ord NNAN, X) --> fcmp ord X, Y
1575  // (fcmp ord Y, X) & (fcmp ord NNAN, X) --> fcmp ord Y, X
1576  // (fcmp ord X, Y) & (fcmp ord X, NNAN) --> fcmp ord X, Y
1577  // (fcmp ord Y, X) & (fcmp ord X, NNAN) --> fcmp ord Y, X
1578  // (fcmp uno X, Y) | (fcmp uno NNAN, X) --> fcmp uno X, Y
1579  // (fcmp uno Y, X) | (fcmp uno NNAN, X) --> fcmp uno Y, X
1580  // (fcmp uno X, Y) | (fcmp uno X, NNAN) --> fcmp uno X, Y
1581  // (fcmp uno Y, X) | (fcmp uno X, NNAN) --> fcmp uno Y, X
1582  if ((isKnownNeverNaN(RHS0) && (RHS1 == LHS0 || RHS1 == LHS1)) ||
1583  (isKnownNeverNaN(RHS1) && (RHS0 == LHS0 || RHS0 == LHS1)))
1584  return LHS;
1585  }
1586 
1587  return nullptr;
1588 }
1589 
1590 static Value *simplifyAndOrOfCmps(Value *Op0, Value *Op1, bool IsAnd) {
1591  // Look through casts of the 'and' operands to find compares.
1592  auto *Cast0 = dyn_cast<CastInst>(Op0);
1593  auto *Cast1 = dyn_cast<CastInst>(Op1);
1594  if (Cast0 && Cast1 && Cast0->getOpcode() == Cast1->getOpcode() &&
1595  Cast0->getSrcTy() == Cast1->getSrcTy()) {
1596  Op0 = Cast0->getOperand(0);
1597  Op1 = Cast1->getOperand(0);
1598  }
1599 
1600  Value *V = nullptr;
1601  auto *ICmp0 = dyn_cast<ICmpInst>(Op0);
1602  auto *ICmp1 = dyn_cast<ICmpInst>(Op1);
1603  if (ICmp0 && ICmp1)
1604  V = IsAnd ? simplifyAndOfICmps(ICmp0, ICmp1) :
1605  simplifyOrOfICmps(ICmp0, ICmp1);
1606 
1607  auto *FCmp0 = dyn_cast<FCmpInst>(Op0);
1608  auto *FCmp1 = dyn_cast<FCmpInst>(Op1);
1609  if (FCmp0 && FCmp1)
1610  V = simplifyAndOrOfFCmps(FCmp0, FCmp1, IsAnd);
1611 
1612  if (!V)
1613  return nullptr;
1614  if (!Cast0)
1615  return V;
1616 
1617  // If we looked through casts, we can only handle a constant simplification
1618  // because we are not allowed to create a cast instruction here.
1619  if (auto *C = dyn_cast<Constant>(V))
1620  return ConstantExpr::getCast(Cast0->getOpcode(), C, Cast0->getType());
1621 
1622  return nullptr;
1623 }
1624 
1625 /// Given operands for an And, see if we can fold the result.
1626 /// If not, this returns null.
1627 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1628  unsigned MaxRecurse) {
1629  if (Constant *C = foldOrCommuteConstant(Instruction::And, Op0, Op1, Q))
1630  return C;
1631 
1632  // X & undef -> 0
1633  if (match(Op1, m_Undef()))
1634  return Constant::getNullValue(Op0->getType());
1635 
1636  // X & X = X
1637  if (Op0 == Op1)
1638  return Op0;
1639 
1640  // X & 0 = 0
1641  if (match(Op1, m_Zero()))
1642  return Op1;
1643 
1644  // X & -1 = X
1645  if (match(Op1, m_AllOnes()))
1646  return Op0;
1647 
1648  // A & ~A = ~A & A = 0
1649  if (match(Op0, m_Not(m_Specific(Op1))) ||
1650  match(Op1, m_Not(m_Specific(Op0))))
1651  return Constant::getNullValue(Op0->getType());
1652 
1653  // (A | ?) & A = A
1654  if (match(Op0, m_c_Or(m_Specific(Op1), m_Value())))
1655  return Op1;
1656 
1657  // A & (A | ?) = A
1658  if (match(Op1, m_c_Or(m_Specific(Op0), m_Value())))
1659  return Op0;
1660 
1661  // A mask that only clears known zeros of a shifted value is a no-op.
1662  Value *X;
1663  const APInt *Mask;
1664  const APInt *ShAmt;
1665  if (match(Op1, m_APInt(Mask))) {
1666  // If all bits in the inverted and shifted mask are clear:
1667  // and (shl X, ShAmt), Mask --> shl X, ShAmt
1668  if (match(Op0, m_Shl(m_Value(X), m_APInt(ShAmt))) &&
1669  (~(*Mask)).lshr(*ShAmt).isNullValue())
1670  return Op0;
1671 
1672  // If all bits in the inverted and shifted mask are clear:
1673  // and (lshr X, ShAmt), Mask --> lshr X, ShAmt
1674  if (match(Op0, m_LShr(m_Value(X), m_APInt(ShAmt))) &&
1675  (~(*Mask)).shl(*ShAmt).isNullValue())
1676  return Op0;
1677  }
1678 
1679  // A & (-A) = A if A is a power of two or zero.
1680  if (match(Op0, m_Neg(m_Specific(Op1))) ||
1681  match(Op1, m_Neg(m_Specific(Op0)))) {
1682  if (isKnownToBeAPowerOfTwo(Op0, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1683  Q.DT))
1684  return Op0;
1685  if (isKnownToBeAPowerOfTwo(Op1, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1686  Q.DT))
1687  return Op1;
1688  }
1689 
1690  if (Value *V = simplifyAndOrOfCmps(Op0, Op1, true))
1691  return V;
1692 
1693  // Try some generic simplifications for associative operations.
1694  if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1695  MaxRecurse))
1696  return V;
1697 
1698  // And distributes over Or. Try some generic simplifications based on this.
1699  if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1700  Q, MaxRecurse))
1701  return V;
1702 
1703  // And distributes over Xor. Try some generic simplifications based on this.
1704  if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1705  Q, MaxRecurse))
1706  return V;
1707 
1708  // If the operation is with the result of a select instruction, check whether
1709  // operating on either branch of the select always yields the same value.
1710  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1711  if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1712  MaxRecurse))
1713  return V;
1714 
1715  // If the operation is with the result of a phi instruction, check whether
1716  // operating on all incoming values of the phi always yields the same value.
1717  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1718  if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1719  MaxRecurse))
1720  return V;
1721 
1722  return nullptr;
1723 }
1724 
1727 }
1728 
1729 /// Given operands for an Or, see if we can fold the result.
1730 /// If not, this returns null.
1731 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1732  unsigned MaxRecurse) {
1733  if (Constant *C = foldOrCommuteConstant(Instruction::Or, Op0, Op1, Q))
1734  return C;
1735 
1736  // X | undef -> -1
1737  if (match(Op1, m_Undef()))
1738  return Constant::getAllOnesValue(Op0->getType());
1739 
1740  // X | X = X
1741  if (Op0 == Op1)
1742  return Op0;
1743 
1744  // X | 0 = X
1745  if (match(Op1, m_Zero()))
1746  return Op0;
1747 
1748  // X | -1 = -1
1749  if (match(Op1, m_AllOnes()))
1750  return Op1;
1751 
1752  // A | ~A = ~A | A = -1
1753  if (match(Op0, m_Not(m_Specific(Op1))) ||
1754  match(Op1, m_Not(m_Specific(Op0))))
1755  return Constant::getAllOnesValue(Op0->getType());
1756 
1757  // (A & ?) | A = A
1758  if (match(Op0, m_c_And(m_Specific(Op1), m_Value())))
1759  return Op1;
1760 
1761  // A | (A & ?) = A
1762  if (match(Op1, m_c_And(m_Specific(Op0), m_Value())))
1763  return Op0;
1764 
1765  // ~(A & ?) | A = -1
1766  if (match(Op0, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
1767  return Constant::getAllOnesValue(Op1->getType());
1768 
1769  // A | ~(A & ?) = -1
1770  if (match(Op1, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
1771  return Constant::getAllOnesValue(Op0->getType());
1772 
1773  Value *A, *B;
1774  // (A & ~B) | (A ^ B) -> (A ^ B)
1775  // (~B & A) | (A ^ B) -> (A ^ B)
1776  // (A & ~B) | (B ^ A) -> (B ^ A)
1777  // (~B & A) | (B ^ A) -> (B ^ A)
1778  if (match(Op1, m_Xor(m_Value(A), m_Value(B))) &&
1779  (match(Op0, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
1780  match(Op0, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
1781  return Op1;
1782 
1783  // Commute the 'or' operands.
1784  // (A ^ B) | (A & ~B) -> (A ^ B)
1785  // (A ^ B) | (~B & A) -> (A ^ B)
1786  // (B ^ A) | (A & ~B) -> (B ^ A)
1787  // (B ^ A) | (~B & A) -> (B ^ A)
1788  if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
1789  (match(Op1, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
1790  match(Op1, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
1791  return Op0;
1792 
1793  // (A & B) | (~A ^ B) -> (~A ^ B)
1794  // (B & A) | (~A ^ B) -> (~A ^ B)
1795  // (A & B) | (B ^ ~A) -> (B ^ ~A)
1796  // (B & A) | (B ^ ~A) -> (B ^ ~A)
1797  if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1798  (match(Op1, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
1799  match(Op1, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
1800  return Op1;
1801 
1802  // (~A ^ B) | (A & B) -> (~A ^ B)
1803  // (~A ^ B) | (B & A) -> (~A ^ B)
1804  // (B ^ ~A) | (A & B) -> (B ^ ~A)
1805  // (B ^ ~A) | (B & A) -> (B ^ ~A)
1806  if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1807  (match(Op0, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
1808  match(Op0, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
1809  return Op0;
1810 
1811  if (Value *V = simplifyAndOrOfCmps(Op0, Op1, false))
1812  return V;
1813 
1814  // Try some generic simplifications for associative operations.
1815  if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1816  MaxRecurse))
1817  return V;
1818 
1819  // Or distributes over And. Try some generic simplifications based on this.
1820  if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1821  MaxRecurse))
1822  return V;
1823 
1824  // If the operation is with the result of a select instruction, check whether
1825  // operating on either branch of the select always yields the same value.
1826  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1827  if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1828  MaxRecurse))
1829  return V;
1830 
1831  // (A & C1)|(B & C2)
1832  const APInt *C1, *C2;
1833  if (match(Op0, m_And(m_Value(A), m_APInt(C1))) &&
1834  match(Op1, m_And(m_Value(B), m_APInt(C2)))) {
1835  if (*C1 == ~*C2) {
1836  // (A & C1)|(B & C2)
1837  // If we have: ((V + N) & C1) | (V & C2)
1838  // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
1839  // replace with V+N.
1840  Value *N;
1841  if (C2->isMask() && // C2 == 0+1+
1842  match(A, m_c_Add(m_Specific(B), m_Value(N)))) {
1843  // Add commutes, try both ways.
1844  if (MaskedValueIsZero(N, *C2, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1845  return A;
1846  }
1847  // Or commutes, try both ways.
1848  if (C1->isMask() &&
1849  match(B, m_c_Add(m_Specific(A), m_Value(N)))) {
1850  // Add commutes, try both ways.
1851  if (MaskedValueIsZero(N, *C1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1852  return B;
1853  }
1854  }
1855  }
1856 
1857  // If the operation is with the result of a phi instruction, check whether
1858  // operating on all incoming values of the phi always yields the same value.
1859  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1860  if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1861  return V;
1862 
1863  return nullptr;
1864 }
1865 
1868 }
1869 
1870 /// Given operands for a Xor, see if we can fold the result.
1871 /// If not, this returns null.
1872 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1873  unsigned MaxRecurse) {
1874  if (Constant *C = foldOrCommuteConstant(Instruction::Xor, Op0, Op1, Q))
1875  return C;
1876 
1877  // A ^ undef -> undef
1878  if (match(Op1, m_Undef()))
1879  return Op1;
1880 
1881  // A ^ 0 = A
1882  if (match(Op1, m_Zero()))
1883  return Op0;
1884 
1885  // A ^ A = 0
1886  if (Op0 == Op1)
1887  return Constant::getNullValue(Op0->getType());
1888 
1889  // A ^ ~A = ~A ^ A = -1
1890  if (match(Op0, m_Not(m_Specific(Op1))) ||
1891  match(Op1, m_Not(m_Specific(Op0))))
1892  return Constant::getAllOnesValue(Op0->getType());
1893 
1894  // Try some generic simplifications for associative operations.
1895  if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1896  MaxRecurse))
1897  return V;
1898 
1899  // Threading Xor over selects and phi nodes is pointless, so don't bother.
1900  // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1901  // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1902  // only if B and C are equal. If B and C are equal then (since we assume
1903  // that operands have already been simplified) "select(cond, B, C)" should
1904  // have been simplified to the common value of B and C already. Analysing
1905  // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1906  // for threading over phi nodes.
1907 
1908  return nullptr;
1909 }
1910 
1913 }
1914 
1915 
1917  return CmpInst::makeCmpResultType(Op->getType());
1918 }
1919 
1920 /// Rummage around inside V looking for something equivalent to the comparison
1921 /// "LHS Pred RHS". Return such a value if found, otherwise return null.
1922 /// Helper function for analyzing max/min idioms.
1924  Value *LHS, Value *RHS) {
1926  if (!SI)
1927  return nullptr;
1928  CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1929  if (!Cmp)
1930  return nullptr;
1931  Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1932  if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1933  return Cmp;
1934  if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1935  LHS == CmpRHS && RHS == CmpLHS)
1936  return Cmp;
1937  return nullptr;
1938 }
1939 
1940 // A significant optimization not implemented here is assuming that alloca
1941 // addresses are not equal to incoming argument values. They don't *alias*,
1942 // as we say, but that doesn't mean they aren't equal, so we take a
1943 // conservative approach.
1944 //
1945 // This is inspired in part by C++11 5.10p1:
1946 // "Two pointers of the same type compare equal if and only if they are both
1947 // null, both point to the same function, or both represent the same
1948 // address."
1949 //
1950 // This is pretty permissive.
1951 //
1952 // It's also partly due to C11 6.5.9p6:
1953 // "Two pointers compare equal if and only if both are null pointers, both are
1954 // pointers to the same object (including a pointer to an object and a
1955 // subobject at its beginning) or function, both are pointers to one past the
1956 // last element of the same array object, or one is a pointer to one past the
1957 // end of one array object and the other is a pointer to the start of a
1958 // different array object that happens to immediately follow the first array
1959 // object in the address space.)
1960 //
1961 // C11's version is more restrictive, however there's no reason why an argument
1962 // couldn't be a one-past-the-end value for a stack object in the caller and be
1963 // equal to the beginning of a stack object in the callee.
1964 //
1965 // If the C and C++ standards are ever made sufficiently restrictive in this
1966 // area, it may be possible to update LLVM's semantics accordingly and reinstate
1967 // this optimization.
1968 static Constant *
1970  const DominatorTree *DT, CmpInst::Predicate Pred,
1971  AssumptionCache *AC, const Instruction *CxtI,
1972  Value *LHS, Value *RHS) {
1973  // First, skip past any trivial no-ops.
1974  LHS = LHS->stripPointerCasts();
1975  RHS = RHS->stripPointerCasts();
1976 
1977  // A non-null pointer is not equal to a null pointer.
1978  if (llvm::isKnownNonZero(LHS, DL) && isa<ConstantPointerNull>(RHS) &&
1979  (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
1980  return ConstantInt::get(GetCompareTy(LHS),
1981  !CmpInst::isTrueWhenEqual(Pred));
1982 
1983  // We can only fold certain predicates on pointer comparisons.
1984  switch (Pred) {
1985  default:
1986  return nullptr;
1987 
1988  // Equality comaprisons are easy to fold.
1989  case CmpInst::ICMP_EQ:
1990  case CmpInst::ICMP_NE:
1991  break;
1992 
1993  // We can only handle unsigned relational comparisons because 'inbounds' on
1994  // a GEP only protects against unsigned wrapping.
1995  case CmpInst::ICMP_UGT:
1996  case CmpInst::ICMP_UGE:
1997  case CmpInst::ICMP_ULT:
1998  case CmpInst::ICMP_ULE:
1999  // However, we have to switch them to their signed variants to handle
2000  // negative indices from the base pointer.
2001  Pred = ICmpInst::getSignedPredicate(Pred);
2002  break;
2003  }
2004 
2005  // Strip off any constant offsets so that we can reason about them.
2006  // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
2007  // here and compare base addresses like AliasAnalysis does, however there are
2008  // numerous hazards. AliasAnalysis and its utilities rely on special rules
2009  // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
2010  // doesn't need to guarantee pointer inequality when it says NoAlias.
2011  Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
2012  Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
2013 
2014  // If LHS and RHS are related via constant offsets to the same base
2015  // value, we can replace it with an icmp which just compares the offsets.
2016  if (LHS == RHS)
2017  return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
2018 
2019  // Various optimizations for (in)equality comparisons.
2020  if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
2021  // Different non-empty allocations that exist at the same time have
2022  // different addresses (if the program can tell). Global variables always
2023  // exist, so they always exist during the lifetime of each other and all
2024  // allocas. Two different allocas usually have different addresses...
2025  //
2026  // However, if there's an @llvm.stackrestore dynamically in between two
2027  // allocas, they may have the same address. It's tempting to reduce the
2028  // scope of the problem by only looking at *static* allocas here. That would
2029  // cover the majority of allocas while significantly reducing the likelihood
2030  // of having an @llvm.stackrestore pop up in the middle. However, it's not
2031  // actually impossible for an @llvm.stackrestore to pop up in the middle of
2032  // an entry block. Also, if we have a block that's not attached to a
2033  // function, we can't tell if it's "static" under the current definition.
2034  // Theoretically, this problem could be fixed by creating a new kind of
2035  // instruction kind specifically for static allocas. Such a new instruction
2036  // could be required to be at the top of the entry block, thus preventing it
2037  // from being subject to a @llvm.stackrestore. Instcombine could even
2038  // convert regular allocas into these special allocas. It'd be nifty.
2039  // However, until then, this problem remains open.
2040  //
2041  // So, we'll assume that two non-empty allocas have different addresses
2042  // for now.
2043  //
2044  // With all that, if the offsets are within the bounds of their allocations
2045  // (and not one-past-the-end! so we can't use inbounds!), and their
2046  // allocations aren't the same, the pointers are not equal.
2047  //
2048  // Note that it's not necessary to check for LHS being a global variable
2049  // address, due to canonicalization and constant folding.
2050  if (isa<AllocaInst>(LHS) &&
2051  (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
2052  ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
2053  ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
2054  uint64_t LHSSize, RHSSize;
2055  if (LHSOffsetCI && RHSOffsetCI &&
2056  getObjectSize(LHS, LHSSize, DL, TLI) &&
2057  getObjectSize(RHS, RHSSize, DL, TLI)) {
2058  const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
2059  const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
2060  if (!LHSOffsetValue.isNegative() &&
2061  !RHSOffsetValue.isNegative() &&
2062  LHSOffsetValue.ult(LHSSize) &&
2063  RHSOffsetValue.ult(RHSSize)) {
2064  return ConstantInt::get(GetCompareTy(LHS),
2065  !CmpInst::isTrueWhenEqual(Pred));
2066  }
2067  }
2068 
2069  // Repeat the above check but this time without depending on DataLayout
2070  // or being able to compute a precise size.
2071  if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
2072  !cast<PointerType>(RHS->getType())->isEmptyTy() &&
2073  LHSOffset->isNullValue() &&
2074  RHSOffset->isNullValue())
2075  return ConstantInt::get(GetCompareTy(LHS),
2076  !CmpInst::isTrueWhenEqual(Pred));
2077  }
2078 
2079  // Even if an non-inbounds GEP occurs along the path we can still optimize
2080  // equality comparisons concerning the result. We avoid walking the whole
2081  // chain again by starting where the last calls to
2082  // stripAndComputeConstantOffsets left off and accumulate the offsets.
2083  Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
2084  Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
2085  if (LHS == RHS)
2086  return ConstantExpr::getICmp(Pred,
2087  ConstantExpr::getAdd(LHSOffset, LHSNoBound),
2088  ConstantExpr::getAdd(RHSOffset, RHSNoBound));
2089 
2090  // If one side of the equality comparison must come from a noalias call
2091  // (meaning a system memory allocation function), and the other side must
2092  // come from a pointer that cannot overlap with dynamically-allocated
2093  // memory within the lifetime of the current function (allocas, byval
2094  // arguments, globals), then determine the comparison result here.
2095  SmallVector<Value *, 8> LHSUObjs, RHSUObjs;
2096  GetUnderlyingObjects(LHS, LHSUObjs, DL);
2097  GetUnderlyingObjects(RHS, RHSUObjs, DL);
2098 
2099  // Is the set of underlying objects all noalias calls?
2100  auto IsNAC = [](ArrayRef<Value *> Objects) {
2101  return all_of(Objects, isNoAliasCall);
2102  };
2103 
2104  // Is the set of underlying objects all things which must be disjoint from
2105  // noalias calls. For allocas, we consider only static ones (dynamic
2106  // allocas might be transformed into calls to malloc not simultaneously
2107  // live with the compared-to allocation). For globals, we exclude symbols
2108  // that might be resolve lazily to symbols in another dynamically-loaded
2109  // library (and, thus, could be malloc'ed by the implementation).
2110  auto IsAllocDisjoint = [](ArrayRef<Value *> Objects) {
2111  return all_of(Objects, [](Value *V) {
2112  if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
2113  return AI->getParent() && AI->getFunction() && AI->isStaticAlloca();
2114  if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
2115  return (GV->hasLocalLinkage() || GV->hasHiddenVisibility() ||
2116  GV->hasProtectedVisibility() || GV->hasGlobalUnnamedAddr()) &&
2117  !GV->isThreadLocal();
2118  if (const Argument *A = dyn_cast<Argument>(V))
2119  return A->hasByValAttr();
2120  return false;
2121  });
2122  };
2123 
2124  if ((IsNAC(LHSUObjs) && IsAllocDisjoint(RHSUObjs)) ||
2125  (IsNAC(RHSUObjs) && IsAllocDisjoint(LHSUObjs)))
2126  return ConstantInt::get(GetCompareTy(LHS),
2127  !CmpInst::isTrueWhenEqual(Pred));
2128 
2129  // Fold comparisons for non-escaping pointer even if the allocation call
2130  // cannot be elided. We cannot fold malloc comparison to null. Also, the
2131  // dynamic allocation call could be either of the operands.
2132  Value *MI = nullptr;
2133  if (isAllocLikeFn(LHS, TLI) &&
2134  llvm::isKnownNonZero(RHS, DL, 0, nullptr, CxtI, DT))
2135  MI = LHS;
2136  else if (isAllocLikeFn(RHS, TLI) &&
2137  llvm::isKnownNonZero(LHS, DL, 0, nullptr, CxtI, DT))
2138  MI = RHS;
2139  // FIXME: We should also fold the compare when the pointer escapes, but the
2140  // compare dominates the pointer escape
2141  if (MI && !PointerMayBeCaptured(MI, true, true))
2142  return ConstantInt::get(GetCompareTy(LHS),
2144  }
2145 
2146  // Otherwise, fail.
2147  return nullptr;
2148 }
2149 
2150 /// Fold an icmp when its operands have i1 scalar type.
2152  Value *RHS, const SimplifyQuery &Q) {
2153  Type *ITy = GetCompareTy(LHS); // The return type.
2154  Type *OpTy = LHS->getType(); // The operand type.
2155  if (!OpTy->isIntOrIntVectorTy(1))
2156  return nullptr;
2157 
2158  // A boolean compared to true/false can be simplified in 14 out of the 20
2159  // (10 predicates * 2 constants) possible combinations. Cases not handled here
2160  // require a 'not' of the LHS, so those must be transformed in InstCombine.
2161  if (match(RHS, m_Zero())) {
2162  switch (Pred) {
2163  case CmpInst::ICMP_NE: // X != 0 -> X
2164  case CmpInst::ICMP_UGT: // X >u 0 -> X
2165  case CmpInst::ICMP_SLT: // X <s 0 -> X
2166  return LHS;
2167 
2168  case CmpInst::ICMP_ULT: // X <u 0 -> false
2169  case CmpInst::ICMP_SGT: // X >s 0 -> false
2170  return getFalse(ITy);
2171 
2172  case CmpInst::ICMP_UGE: // X >=u 0 -> true
2173  case CmpInst::ICMP_SLE: // X <=s 0 -> true
2174  return getTrue(ITy);
2175 
2176  default: break;
2177  }
2178  } else if (match(RHS, m_One())) {
2179  switch (Pred) {
2180  case CmpInst::ICMP_EQ: // X == 1 -> X
2181  case CmpInst::ICMP_UGE: // X >=u 1 -> X
2182  case CmpInst::ICMP_SLE: // X <=s -1 -> X
2183  return LHS;
2184 
2185  case CmpInst::ICMP_UGT: // X >u 1 -> false
2186  case CmpInst::ICMP_SLT: // X <s -1 -> false
2187  return getFalse(ITy);
2188 
2189  case CmpInst::ICMP_ULE: // X <=u 1 -> true
2190  case CmpInst::ICMP_SGE: // X >=s -1 -> true
2191  return getTrue(ITy);
2192 
2193  default: break;
2194  }
2195  }
2196 
2197  switch (Pred) {
2198  default:
2199  break;
2200  case ICmpInst::ICMP_UGE:
2201  if (isImpliedCondition(RHS, LHS, Q.DL).getValueOr(false))
2202  return getTrue(ITy);
2203  break;
2204  case ICmpInst::ICMP_SGE:
2205  /// For signed comparison, the values for an i1 are 0 and -1
2206  /// respectively. This maps into a truth table of:
2207  /// LHS | RHS | LHS >=s RHS | LHS implies RHS
2208  /// 0 | 0 | 1 (0 >= 0) | 1
2209  /// 0 | 1 | 1 (0 >= -1) | 1
2210  /// 1 | 0 | 0 (-1 >= 0) | 0
2211  /// 1 | 1 | 1 (-1 >= -1) | 1
2212  if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2213  return getTrue(ITy);
2214  break;
2215  case ICmpInst::ICMP_ULE:
2216  if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2217  return getTrue(ITy);
2218  break;
2219  }
2220 
2221  return nullptr;
2222 }
2223 
2224 /// Try hard to fold icmp with zero RHS because this is a common case.
2226  Value *RHS, const SimplifyQuery &Q) {
2227  if (!match(RHS, m_Zero()))
2228  return nullptr;
2229 
2230  Type *ITy = GetCompareTy(LHS); // The return type.
2231  switch (Pred) {
2232  default:
2233  llvm_unreachable("Unknown ICmp predicate!");
2234  case ICmpInst::ICMP_ULT:
2235  return getFalse(ITy);
2236  case ICmpInst::ICMP_UGE:
2237  return getTrue(ITy);
2238  case ICmpInst::ICMP_EQ:
2239  case ICmpInst::ICMP_ULE:
2240  if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2241  return getFalse(ITy);
2242  break;
2243  case ICmpInst::ICMP_NE:
2244  case ICmpInst::ICMP_UGT:
2245  if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2246  return getTrue(ITy);
2247  break;
2248  case ICmpInst::ICMP_SLT: {
2249  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2250  if (LHSKnown.isNegative())
2251  return getTrue(ITy);
2252  if (LHSKnown.isNonNegative())
2253  return getFalse(ITy);
2254  break;
2255  }
2256  case ICmpInst::ICMP_SLE: {
2257  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2258  if (LHSKnown.isNegative())
2259  return getTrue(ITy);
2260  if (LHSKnown.isNonNegative() &&
2261  isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2262  return getFalse(ITy);
2263  break;
2264  }
2265  case ICmpInst::ICMP_SGE: {
2266  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2267  if (LHSKnown.isNegative())
2268  return getFalse(ITy);
2269  if (LHSKnown.isNonNegative())
2270  return getTrue(ITy);
2271  break;
2272  }
2273  case ICmpInst::ICMP_SGT: {
2274  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2275  if (LHSKnown.isNegative())
2276  return getFalse(ITy);
2277  if (LHSKnown.isNonNegative() &&
2278  isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2279  return getTrue(ITy);
2280  break;
2281  }
2282  }
2283 
2284  return nullptr;
2285 }
2286 
2287 /// Many binary operators with a constant operand have an easy-to-compute
2288 /// range of outputs. This can be used to fold a comparison to always true or
2289 /// always false.
2290 static void setLimitsForBinOp(BinaryOperator &BO, APInt &Lower, APInt &Upper) {
2291  unsigned Width = Lower.getBitWidth();
2292  const APInt *C;
2293  switch (BO.getOpcode()) {
2294  case Instruction::Add:
2295  if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
2296  // FIXME: If we have both nuw and nsw, we should reduce the range further.
2297  if (BO.hasNoUnsignedWrap()) {
2298  // 'add nuw x, C' produces [C, UINT_MAX].
2299  Lower = *C;
2300  } else if (BO.hasNoSignedWrap()) {
2301  if (C->isNegative()) {
2302  // 'add nsw x, -C' produces [SINT_MIN, SINT_MAX - C].
2303  Lower = APInt::getSignedMinValue(Width);
2304  Upper = APInt::getSignedMaxValue(Width) + *C + 1;
2305  } else {
2306  // 'add nsw x, +C' produces [SINT_MIN + C, SINT_MAX].
2307  Lower = APInt::getSignedMinValue(Width) + *C;
2308  Upper = APInt::getSignedMaxValue(Width) + 1;
2309  }
2310  }
2311  }
2312  break;
2313 
2314  case Instruction::And:
2315  if (match(BO.getOperand(1), m_APInt(C)))
2316  // 'and x, C' produces [0, C].
2317  Upper = *C + 1;
2318  break;
2319 
2320  case Instruction::Or:
2321  if (match(BO.getOperand(1), m_APInt(C)))
2322  // 'or x, C' produces [C, UINT_MAX].
2323  Lower = *C;
2324  break;
2325 
2326  case Instruction::AShr:
2327  if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
2328  // 'ashr x, C' produces [INT_MIN >> C, INT_MAX >> C].
2329  Lower = APInt::getSignedMinValue(Width).ashr(*C);
2330  Upper = APInt::getSignedMaxValue(Width).ashr(*C) + 1;
2331  } else if (match(BO.getOperand(0), m_APInt(C))) {
2332  unsigned ShiftAmount = Width - 1;
2333  if (!C->isNullValue() && BO.isExact())
2334  ShiftAmount = C->countTrailingZeros();
2335  if (C->isNegative()) {
2336  // 'ashr C, x' produces [C, C >> (Width-1)]
2337  Lower = *C;
2338  Upper = C->ashr(ShiftAmount) + 1;
2339  } else {
2340  // 'ashr C, x' produces [C >> (Width-1), C]
2341  Lower = C->ashr(ShiftAmount);
2342  Upper = *C + 1;
2343  }
2344  }
2345  break;
2346 
2347  case Instruction::LShr:
2348  if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
2349  // 'lshr x, C' produces [0, UINT_MAX >> C].
2350  Upper = APInt::getAllOnesValue(Width).lshr(*C) + 1;
2351  } else if (match(BO.getOperand(0), m_APInt(C))) {
2352  // 'lshr C, x' produces [C >> (Width-1), C].
2353  unsigned ShiftAmount = Width - 1;
2354  if (!C->isNullValue() && BO.isExact())
2355  ShiftAmount = C->countTrailingZeros();
2356  Lower = C->lshr(ShiftAmount);
2357  Upper = *C + 1;
2358  }
2359  break;
2360 
2361  case Instruction::Shl:
2362  if (match(BO.getOperand(0), m_APInt(C))) {
2363  if (BO.hasNoUnsignedWrap()) {
2364  // 'shl nuw C, x' produces [C, C << CLZ(C)]
2365  Lower = *C;
2366  Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
2367  } else if (BO.hasNoSignedWrap()) { // TODO: What if both nuw+nsw?
2368  if (C->isNegative()) {
2369  // 'shl nsw C, x' produces [C << CLO(C)-1, C]
2370  unsigned ShiftAmount = C->countLeadingOnes() - 1;
2371  Lower = C->shl(ShiftAmount);
2372  Upper = *C + 1;
2373  } else {
2374  // 'shl nsw C, x' produces [C, C << CLZ(C)-1]
2375  unsigned ShiftAmount = C->countLeadingZeros() - 1;
2376  Lower = *C;
2377  Upper = C->shl(ShiftAmount) + 1;
2378  }
2379  }
2380  }
2381  break;
2382 
2383  case Instruction::SDiv:
2384  if (match(BO.getOperand(1), m_APInt(C))) {
2385  APInt IntMin = APInt::getSignedMinValue(Width);
2386  APInt IntMax = APInt::getSignedMaxValue(Width);
2387  if (C->isAllOnesValue()) {
2388  // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
2389  // where C != -1 and C != 0 and C != 1
2390  Lower = IntMin + 1;
2391  Upper = IntMax + 1;
2392  } else if (C->countLeadingZeros() < Width - 1) {
2393  // 'sdiv x, C' produces [INT_MIN / C, INT_MAX / C]
2394  // where C != -1 and C != 0 and C != 1
2395  Lower = IntMin.sdiv(*C);
2396  Upper = IntMax.sdiv(*C);
2397  if (Lower.sgt(Upper))
2398  std::swap(Lower, Upper);
2399  Upper = Upper + 1;
2400  assert(Upper != Lower && "Upper part of range has wrapped!");
2401  }
2402  } else if (match(BO.getOperand(0), m_APInt(C))) {
2403  if (C->isMinSignedValue()) {
2404  // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
2405  Lower = *C;
2406  Upper = Lower.lshr(1) + 1;
2407  } else {
2408  // 'sdiv C, x' produces [-|C|, |C|].
2409  Upper = C->abs() + 1;
2410  Lower = (-Upper) + 1;
2411  }
2412  }
2413  break;
2414 
2415  case Instruction::UDiv:
2416  if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
2417  // 'udiv x, C' produces [0, UINT_MAX / C].
2418  Upper = APInt::getMaxValue(Width).udiv(*C) + 1;
2419  } else if (match(BO.getOperand(0), m_APInt(C))) {
2420  // 'udiv C, x' produces [0, C].
2421  Upper = *C + 1;
2422  }
2423  break;
2424 
2425  case Instruction::SRem:
2426  if (match(BO.getOperand(1), m_APInt(C))) {
2427  // 'srem x, C' produces (-|C|, |C|).
2428  Upper = C->abs();
2429  Lower = (-Upper) + 1;
2430  }
2431  break;
2432 
2433  case Instruction::URem:
2434  if (match(BO.getOperand(1), m_APInt(C)))
2435  // 'urem x, C' produces [0, C).
2436  Upper = *C;
2437  break;
2438 
2439  default:
2440  break;
2441  }
2442 }
2443 
2445  Value *RHS) {
2446  const APInt *C;
2447  if (!match(RHS, m_APInt(C)))
2448  return nullptr;
2449 
2450  // Rule out tautological comparisons (eg., ult 0 or uge 0).
2452  if (RHS_CR.isEmptySet())
2453  return ConstantInt::getFalse(GetCompareTy(RHS));
2454  if (RHS_CR.isFullSet())
2455  return ConstantInt::getTrue(GetCompareTy(RHS));
2456 
2457  // Find the range of possible values for binary operators.
2458  unsigned Width = C->getBitWidth();
2459  APInt Lower = APInt(Width, 0);
2460  APInt Upper = APInt(Width, 0);
2461  if (auto *BO = dyn_cast<BinaryOperator>(LHS))
2462  setLimitsForBinOp(*BO, Lower, Upper);
2463 
2464  ConstantRange LHS_CR =
2465  Lower != Upper ? ConstantRange(Lower, Upper) : ConstantRange(Width, true);
2466 
2467  if (auto *I = dyn_cast<Instruction>(LHS))
2468  if (auto *Ranges = I->getMetadata(LLVMContext::MD_range))
2469  LHS_CR = LHS_CR.intersectWith(getConstantRangeFromMetadata(*Ranges));
2470 
2471  if (!LHS_CR.isFullSet()) {
2472  if (RHS_CR.contains(LHS_CR))
2473  return ConstantInt::getTrue(GetCompareTy(RHS));
2474  if (RHS_CR.inverse().contains(LHS_CR))
2475  return ConstantInt::getFalse(GetCompareTy(RHS));
2476  }
2477 
2478  return nullptr;
2479 }
2480 
2481 /// TODO: A large part of this logic is duplicated in InstCombine's
2482 /// foldICmpBinOp(). We should be able to share that and avoid the code
2483 /// duplication.
2485  Value *RHS, const SimplifyQuery &Q,
2486  unsigned MaxRecurse) {
2487  Type *ITy = GetCompareTy(LHS); // The return type.
2488 
2489  BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2490  BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2491  if (MaxRecurse && (LBO || RBO)) {
2492  // Analyze the case when either LHS or RHS is an add instruction.
2493  Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
2494  // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2495  bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2496  if (LBO && LBO->getOpcode() == Instruction::Add) {
2497  A = LBO->getOperand(0);
2498  B = LBO->getOperand(1);
2499  NoLHSWrapProblem =
2500  ICmpInst::isEquality(Pred) ||
2501  (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2502  (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2503  }
2504  if (RBO && RBO->getOpcode() == Instruction::Add) {
2505  C = RBO->getOperand(0);
2506  D = RBO->getOperand(1);
2507  NoRHSWrapProblem =
2508  ICmpInst::isEquality(Pred) ||
2509  (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2510  (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2511  }
2512 
2513  // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2514  if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2515  if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2516  Constant::getNullValue(RHS->getType()), Q,
2517  MaxRecurse - 1))
2518  return V;
2519 
2520  // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2521  if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2522  if (Value *V =
2524  C == LHS ? D : C, Q, MaxRecurse - 1))
2525  return V;
2526 
2527  // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2528  if (A && C && (A == C || A == D || B == C || B == D) && NoLHSWrapProblem &&
2529  NoRHSWrapProblem) {
2530  // Determine Y and Z in the form icmp (X+Y), (X+Z).
2531  Value *Y, *Z;
2532  if (A == C) {
2533  // C + B == C + D -> B == D
2534  Y = B;
2535  Z = D;
2536  } else if (A == D) {
2537  // D + B == C + D -> B == C
2538  Y = B;
2539  Z = C;
2540  } else if (B == C) {
2541  // A + C == C + D -> A == D
2542  Y = A;
2543  Z = D;
2544  } else {
2545  assert(B == D);
2546  // A + D == C + D -> A == C
2547  Y = A;
2548  Z = C;
2549  }
2550  if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse - 1))
2551  return V;
2552  }
2553  }
2554 
2555  {
2556  Value *Y = nullptr;
2557  // icmp pred (or X, Y), X
2558  if (LBO && match(LBO, m_c_Or(m_Value(Y), m_Specific(RHS)))) {
2559  if (Pred == ICmpInst::ICMP_ULT)
2560  return getFalse(ITy);
2561  if (Pred == ICmpInst::ICMP_UGE)
2562  return getTrue(ITy);
2563 
2564  if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SGE) {
2565  KnownBits RHSKnown = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2566  KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2567  if (RHSKnown.isNonNegative() && YKnown.isNegative())
2568  return Pred == ICmpInst::ICMP_SLT ? getTrue(ITy) : getFalse(ITy);
2569  if (RHSKnown.isNegative() || YKnown.isNonNegative())
2570  return Pred == ICmpInst::ICMP_SLT ? getFalse(ITy) : getTrue(ITy);
2571  }
2572  }
2573  // icmp pred X, (or X, Y)
2574  if (RBO && match(RBO, m_c_Or(m_Value(Y), m_Specific(LHS)))) {
2575  if (Pred == ICmpInst::ICMP_ULE)
2576  return getTrue(ITy);
2577  if (Pred == ICmpInst::ICMP_UGT)
2578  return getFalse(ITy);
2579 
2580  if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SLE) {
2581  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2582  KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2583  if (LHSKnown.isNonNegative() && YKnown.isNegative())
2584  return Pred == ICmpInst::ICMP_SGT ? getTrue(ITy) : getFalse(ITy);
2585  if (LHSKnown.isNegative() || YKnown.isNonNegative())
2586  return Pred == ICmpInst::ICMP_SGT ? getFalse(ITy) : getTrue(ITy);
2587  }
2588  }
2589  }
2590 
2591  // icmp pred (and X, Y), X
2592  if (LBO && match(LBO, m_c_And(m_Value(), m_Specific(RHS)))) {
2593  if (Pred == ICmpInst::ICMP_UGT)
2594  return getFalse(ITy);
2595  if (Pred == ICmpInst::ICMP_ULE)
2596  return getTrue(ITy);
2597  }
2598  // icmp pred X, (and X, Y)
2599  if (RBO && match(RBO, m_c_And(m_Value(), m_Specific(LHS)))) {
2600  if (Pred == ICmpInst::ICMP_UGE)
2601  return getTrue(ITy);
2602  if (Pred == ICmpInst::ICMP_ULT)
2603  return getFalse(ITy);
2604  }
2605 
2606  // 0 - (zext X) pred C
2607  if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
2608  if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
2609  if (RHSC->getValue().isStrictlyPositive()) {
2610  if (Pred == ICmpInst::ICMP_SLT)
2611  return ConstantInt::getTrue(RHSC->getContext());
2612  if (Pred == ICmpInst::ICMP_SGE)
2613  return ConstantInt::getFalse(RHSC->getContext());
2614  if (Pred == ICmpInst::ICMP_EQ)
2615  return ConstantInt::getFalse(RHSC->getContext());
2616  if (Pred == ICmpInst::ICMP_NE)
2617  return ConstantInt::getTrue(RHSC->getContext());
2618  }
2619  if (RHSC->getValue().isNonNegative()) {
2620  if (Pred == ICmpInst::ICMP_SLE)
2621  return ConstantInt::getTrue(RHSC->getContext());
2622  if (Pred == ICmpInst::ICMP_SGT)
2623  return ConstantInt::getFalse(RHSC->getContext());
2624  }
2625  }
2626  }
2627 
2628  // icmp pred (urem X, Y), Y
2629  if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2630  switch (Pred) {
2631  default:
2632  break;
2633  case ICmpInst::ICMP_SGT:
2634  case ICmpInst::ICMP_SGE: {
2635  KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2636  if (!Known.isNonNegative())
2637  break;
2639  }
2640  case ICmpInst::ICMP_EQ:
2641  case ICmpInst::ICMP_UGT:
2642  case ICmpInst::ICMP_UGE:
2643  return getFalse(ITy);
2644  case ICmpInst::ICMP_SLT:
2645  case ICmpInst::ICMP_SLE: {
2646  KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2647  if (!Known.isNonNegative())
2648  break;
2650  }
2651  case ICmpInst::ICMP_NE:
2652  case ICmpInst::ICMP_ULT:
2653  case ICmpInst::ICMP_ULE:
2654  return getTrue(ITy);
2655  }
2656  }
2657 
2658  // icmp pred X, (urem Y, X)
2659  if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2660  switch (Pred) {
2661  default:
2662  break;
2663  case ICmpInst::ICMP_SGT:
2664  case ICmpInst::ICMP_SGE: {
2665  KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2666  if (!Known.isNonNegative())
2667  break;
2669  }
2670  case ICmpInst::ICMP_NE:
2671  case ICmpInst::ICMP_UGT:
2672  case ICmpInst::ICMP_UGE:
2673  return getTrue(ITy);
2674  case ICmpInst::ICMP_SLT:
2675  case ICmpInst::ICMP_SLE: {
2676  KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2677  if (!Known.isNonNegative())
2678  break;
2680  }
2681  case ICmpInst::ICMP_EQ:
2682  case ICmpInst::ICMP_ULT:
2683  case ICmpInst::ICMP_ULE:
2684  return getFalse(ITy);
2685  }
2686  }
2687 
2688  // x >> y <=u x
2689  // x udiv y <=u x.
2690  if (LBO && (match(LBO, m_LShr(m_Specific(RHS), m_Value())) ||
2691  match(LBO, m_UDiv(m_Specific(RHS), m_Value())))) {
2692  // icmp pred (X op Y), X
2693  if (Pred == ICmpInst::ICMP_UGT)
2694  return getFalse(ITy);
2695  if (Pred == ICmpInst::ICMP_ULE)
2696  return getTrue(ITy);
2697  }
2698 
2699  // x >=u x >> y
2700  // x >=u x udiv y.
2701  if (RBO && (match(RBO, m_LShr(m_Specific(LHS), m_Value())) ||
2702  match(RBO, m_UDiv(m_Specific(LHS), m_Value())))) {
2703  // icmp pred X, (X op Y)
2704  if (Pred == ICmpInst::ICMP_ULT)
2705  return getFalse(ITy);
2706  if (Pred == ICmpInst::ICMP_UGE)
2707  return getTrue(ITy);
2708  }
2709 
2710  // handle:
2711  // CI2 << X == CI
2712  // CI2 << X != CI
2713  //
2714  // where CI2 is a power of 2 and CI isn't
2715  if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
2716  const APInt *CI2Val, *CIVal = &CI->getValue();
2717  if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
2718  CI2Val->isPowerOf2()) {
2719  if (!CIVal->isPowerOf2()) {
2720  // CI2 << X can equal zero in some circumstances,
2721  // this simplification is unsafe if CI is zero.
2722  //
2723  // We know it is safe if:
2724  // - The shift is nsw, we can't shift out the one bit.
2725  // - The shift is nuw, we can't shift out the one bit.
2726  // - CI2 is one
2727  // - CI isn't zero
2728  if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
2729  CI2Val->isOneValue() || !CI->isZero()) {
2730  if (Pred == ICmpInst::ICMP_EQ)
2731  return ConstantInt::getFalse(RHS->getContext());
2732  if (Pred == ICmpInst::ICMP_NE)
2733  return ConstantInt::getTrue(RHS->getContext());
2734  }
2735  }
2736  if (CIVal->isSignMask() && CI2Val->isOneValue()) {
2737  if (Pred == ICmpInst::ICMP_UGT)
2738  return ConstantInt::getFalse(RHS->getContext());
2739  if (Pred == ICmpInst::ICMP_ULE)
2740  return ConstantInt::getTrue(RHS->getContext());
2741  }
2742  }
2743  }
2744 
2745  if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2746  LBO->getOperand(1) == RBO->getOperand(1)) {
2747  switch (LBO->getOpcode()) {
2748  default:
2749  break;
2750  case Instruction::UDiv:
2751  case Instruction::LShr:
2752  if (ICmpInst::isSigned(Pred) || !LBO->isExact() || !RBO->isExact())
2753  break;
2754  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2755  RBO->getOperand(0), Q, MaxRecurse - 1))
2756  return V;
2757  break;
2758  case Instruction::SDiv:
2759  if (!ICmpInst::isEquality(Pred) || !LBO->isExact() || !RBO->isExact())
2760  break;
2761  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2762  RBO->getOperand(0), Q, MaxRecurse - 1))
2763  return V;
2764  break;
2765  case Instruction::AShr:
2766  if (!LBO->isExact() || !RBO->isExact())
2767  break;
2768  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2769  RBO->getOperand(0), Q, MaxRecurse - 1))
2770  return V;
2771  break;
2772  case Instruction::Shl: {
2773  bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2774  bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2775  if (!NUW && !NSW)
2776  break;
2777  if (!NSW && ICmpInst::isSigned(Pred))
2778  break;
2779  if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2780  RBO->getOperand(0), Q, MaxRecurse - 1))
2781  return V;
2782  break;
2783  }
2784  }
2785  }
2786  return nullptr;
2787 }
2788 
2789 /// Simplify integer comparisons where at least one operand of the compare
2790 /// matches an integer min/max idiom.
2792  Value *RHS, const SimplifyQuery &Q,
2793  unsigned MaxRecurse) {
2794  Type *ITy = GetCompareTy(LHS); // The return type.
2795  Value *A, *B;
2797  CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2798 
2799  // Signed variants on "max(a,b)>=a -> true".
2800  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2801  if (A != RHS)
2802  std::swap(A, B); // smax(A, B) pred A.
2803  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2804  // We analyze this as smax(A, B) pred A.
2805  P = Pred;
2806  } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2807  (A == LHS || B == LHS)) {
2808  if (A != LHS)
2809  std::swap(A, B); // A pred smax(A, B).
2810  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2811  // We analyze this as smax(A, B) swapped-pred A.
2812  P = CmpInst::getSwappedPredicate(Pred);
2813  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2814  (A == RHS || B == RHS)) {
2815  if (A != RHS)
2816  std::swap(A, B); // smin(A, B) pred A.
2817  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2818  // We analyze this as smax(-A, -B) swapped-pred -A.
2819  // Note that we do not need to actually form -A or -B thanks to EqP.
2820  P = CmpInst::getSwappedPredicate(Pred);
2821  } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2822  (A == LHS || B == LHS)) {
2823  if (A != LHS)
2824  std::swap(A, B); // A pred smin(A, B).
2825  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2826  // We analyze this as smax(-A, -B) pred -A.
2827  // Note that we do not need to actually form -A or -B thanks to EqP.
2828  P = Pred;
2829  }
2830  if (P != CmpInst::BAD_ICMP_PREDICATE) {
2831  // Cases correspond to "max(A, B) p A".
2832  switch (P) {
2833  default:
2834  break;
2835  case CmpInst::ICMP_EQ:
2836  case CmpInst::ICMP_SLE:
2837  // Equivalent to "A EqP B". This may be the same as the condition tested
2838  // in the max/min; if so, we can just return that.
2839  if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2840  return V;
2841  if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2842  return V;
2843  // Otherwise, see if "A EqP B" simplifies.
2844  if (MaxRecurse)
2845  if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
2846  return V;
2847  break;
2848  case CmpInst::ICMP_NE:
2849  case CmpInst::ICMP_SGT: {
2851  // Equivalent to "A InvEqP B". This may be the same as the condition
2852  // tested in the max/min; if so, we can just return that.
2853  if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2854  return V;
2855  if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2856  return V;
2857  // Otherwise, see if "A InvEqP B" simplifies.
2858  if (MaxRecurse)
2859  if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
2860  return V;
2861  break;
2862  }
2863  case CmpInst::ICMP_SGE:
2864  // Always true.
2865  return getTrue(ITy);
2866  case CmpInst::ICMP_SLT:
2867  // Always false.
2868  return getFalse(ITy);
2869  }
2870  }
2871 
2872  // Unsigned variants on "max(a,b)>=a -> true".
2874  if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2875  if (A != RHS)
2876  std::swap(A, B); // umax(A, B) pred A.
2877  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2878  // We analyze this as umax(A, B) pred A.
2879  P = Pred;
2880  } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2881  (A == LHS || B == LHS)) {
2882  if (A != LHS)
2883  std::swap(A, B); // A pred umax(A, B).
2884  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2885  // We analyze this as umax(A, B) swapped-pred A.
2886  P = CmpInst::getSwappedPredicate(Pred);
2887  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2888  (A == RHS || B == RHS)) {
2889  if (A != RHS)
2890  std::swap(A, B); // umin(A, B) pred A.
2891  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2892  // We analyze this as umax(-A, -B) swapped-pred -A.
2893  // Note that we do not need to actually form -A or -B thanks to EqP.
2894  P = CmpInst::getSwappedPredicate(Pred);
2895  } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2896  (A == LHS || B == LHS)) {
2897  if (A != LHS)
2898  std::swap(A, B); // A pred umin(A, B).
2899  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2900  // We analyze this as umax(-A, -B) pred -A.
2901  // Note that we do not need to actually form -A or -B thanks to EqP.
2902  P = Pred;
2903  }
2904  if (P != CmpInst::BAD_ICMP_PREDICATE) {
2905  // Cases correspond to "max(A, B) p A".
2906  switch (P) {
2907  default:
2908  break;
2909  case CmpInst::ICMP_EQ:
2910  case CmpInst::ICMP_ULE:
2911  // Equivalent to "A EqP B". This may be the same as the condition tested
2912  // in the max/min; if so, we can just return that.
2913  if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2914  return V;
2915  if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2916  return V;
2917  // Otherwise, see if "A EqP B" simplifies.
2918  if (MaxRecurse)
2919  if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
2920  return V;
2921  break;
2922  case CmpInst::ICMP_NE:
2923  case CmpInst::ICMP_UGT: {
2925  // Equivalent to "A InvEqP B". This may be the same as the condition
2926  // tested in the max/min; if so, we can just return that.
2927  if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2928  return V;
2929  if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2930  return V;
2931  // Otherwise, see if "A InvEqP B" simplifies.
2932  if (MaxRecurse)
2933  if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
2934  return V;
2935  break;
2936  }
2937  case CmpInst::ICMP_UGE:
2938  // Always true.
2939  return getTrue(ITy);
2940  case CmpInst::ICMP_ULT:
2941  // Always false.
2942  return getFalse(ITy);
2943  }
2944  }
2945 
2946  // Variants on "max(x,y) >= min(x,z)".
2947  Value *C, *D;
2948  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2949  match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2950  (A == C || A == D || B == C || B == D)) {
2951  // max(x, ?) pred min(x, ?).
2952  if (Pred == CmpInst::ICMP_SGE)
2953  // Always true.
2954  return getTrue(ITy);
2955  if (Pred == CmpInst::ICMP_SLT)
2956  // Always false.
2957  return getFalse(ITy);
2958  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2959  match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2960  (A == C || A == D || B == C || B == D)) {
2961  // min(x, ?) pred max(x, ?).
2962  if (Pred == CmpInst::ICMP_SLE)
2963  // Always true.
2964  return getTrue(ITy);
2965  if (Pred == CmpInst::ICMP_SGT)
2966  // Always false.
2967  return getFalse(ITy);
2968  } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2969  match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2970  (A == C || A == D || B == C || B == D)) {
2971  // max(x, ?) pred min(x, ?).
2972  if (Pred == CmpInst::ICMP_UGE)
2973  // Always true.
2974  return getTrue(ITy);
2975  if (Pred == CmpInst::ICMP_ULT)
2976  // Always false.
2977  return getFalse(ITy);
2978  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2979  match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2980  (A == C || A == D || B == C || B == D)) {
2981  // min(x, ?) pred max(x, ?).
2982  if (Pred == CmpInst::ICMP_ULE)
2983  // Always true.
2984  return getTrue(ITy);
2985  if (Pred == CmpInst::ICMP_UGT)
2986  // Always false.
2987  return getFalse(ITy);
2988  }
2989 
2990  return nullptr;
2991 }
2992 
2993 /// Given operands for an ICmpInst, see if we can fold the result.
2994 /// If not, this returns null.
2995 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2996  const SimplifyQuery &Q, unsigned MaxRecurse) {
2997  CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2998  assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
2999 
3000  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3001  if (Constant *CRHS = dyn_cast<Constant>(RHS))
3002  return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3003 
3004  // If we have a constant, make sure it is on the RHS.
3005  std::swap(LHS, RHS);
3006  Pred = CmpInst::getSwappedPredicate(Pred);
3007  }
3008 
3009  Type *ITy = GetCompareTy(LHS); // The return type.
3010 
3011  // icmp X, X -> true/false
3012  // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
3013  // because X could be 0.
3014  if (LHS == RHS || isa<UndefValue>(RHS))
3015  return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
3016 
3017  if (Value *V = simplifyICmpOfBools(Pred, LHS, RHS, Q))
3018  return V;
3019 
3020  if (Value *V = simplifyICmpWithZero(Pred, LHS, RHS, Q))
3021  return V;
3022 
3023  if (Value *V = simplifyICmpWithConstant(Pred, LHS, RHS))
3024  return V;
3025 
3026  // If both operands have range metadata, use the metadata
3027  // to simplify the comparison.
3028  if (isa<Instruction>(RHS) && isa<Instruction>(LHS)) {
3029  auto RHS_Instr = cast<Instruction>(RHS);
3030  auto LHS_Instr = cast<Instruction>(LHS);
3031 
3032  if (RHS_Instr->getMetadata(LLVMContext::MD_range) &&
3033  LHS_Instr->getMetadata(LLVMContext::MD_range)) {
3034  auto RHS_CR = getConstantRangeFromMetadata(
3035  *RHS_Instr->getMetadata(LLVMContext::MD_range));
3036  auto LHS_CR = getConstantRangeFromMetadata(
3037  *LHS_Instr->getMetadata(LLVMContext::MD_range));
3038 
3039  auto Satisfied_CR = ConstantRange::makeSatisfyingICmpRegion(Pred, RHS_CR);
3040  if (Satisfied_CR.contains(LHS_CR))
3041  return ConstantInt::getTrue(RHS->getContext());
3042 
3043  auto InversedSatisfied_CR = ConstantRange::makeSatisfyingICmpRegion(
3044  CmpInst::getInversePredicate(Pred), RHS_CR);
3045  if (InversedSatisfied_CR.contains(LHS_CR))
3046  return ConstantInt::getFalse(RHS->getContext());
3047  }
3048  }
3049 
3050  // Compare of cast, for example (zext X) != 0 -> X != 0
3051  if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
3052  Instruction *LI = cast<CastInst>(LHS);
3053  Value *SrcOp = LI->getOperand(0);
3054  Type *SrcTy = SrcOp->getType();
3055  Type *DstTy = LI->getType();
3056 
3057  // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
3058  // if the integer type is the same size as the pointer type.
3059  if (MaxRecurse && isa<PtrToIntInst>(LI) &&
3060  Q.DL.getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
3061  if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
3062  // Transfer the cast to the constant.
3063  if (Value *V = SimplifyICmpInst(Pred, SrcOp,
3064  ConstantExpr::getIntToPtr(RHSC, SrcTy),
3065  Q, MaxRecurse-1))
3066  return V;
3067  } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
3068  if (RI->getOperand(0)->getType() == SrcTy)
3069  // Compare without the cast.
3070  if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
3071  Q, MaxRecurse-1))
3072  return V;
3073  }
3074  }
3075 
3076  if (isa<ZExtInst>(LHS)) {
3077  // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
3078  // same type.
3079  if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
3080  if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3081  // Compare X and Y. Note that signed predicates become unsigned.
3083  SrcOp, RI->getOperand(0), Q,
3084  MaxRecurse-1))
3085  return V;
3086  }
3087  // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
3088  // too. If not, then try to deduce the result of the comparison.
3089  else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3090  // Compute the constant that would happen if we truncated to SrcTy then
3091  // reextended to DstTy.
3092  Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3093  Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
3094 
3095  // If the re-extended constant didn't change then this is effectively
3096  // also a case of comparing two zero-extended values.
3097  if (RExt == CI && MaxRecurse)
3099  SrcOp, Trunc, Q, MaxRecurse-1))
3100  return V;
3101 
3102  // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
3103  // there. Use this to work out the result of the comparison.
3104  if (RExt != CI) {
3105  switch (Pred) {
3106  default: llvm_unreachable("Unknown ICmp predicate!");
3107  // LHS <u RHS.
3108  case ICmpInst::ICMP_EQ:
3109  case ICmpInst::ICMP_UGT:
3110  case ICmpInst::ICMP_UGE:
3111  return ConstantInt::getFalse(CI->getContext());
3112 
3113  case ICmpInst::ICMP_NE:
3114  case ICmpInst::ICMP_ULT:
3115  case ICmpInst::ICMP_ULE:
3116  return ConstantInt::getTrue(CI->getContext());
3117 
3118  // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
3119  // is non-negative then LHS <s RHS.
3120  case ICmpInst::ICMP_SGT:
3121  case ICmpInst::ICMP_SGE:
3122  return CI->getValue().isNegative() ?
3123  ConstantInt::getTrue(CI->getContext()) :
3124  ConstantInt::getFalse(CI->getContext());
3125 
3126  case ICmpInst::ICMP_SLT:
3127  case ICmpInst::ICMP_SLE:
3128  return CI->getValue().isNegative() ?
3129  ConstantInt::getFalse(CI->getContext()) :
3130  ConstantInt::getTrue(CI->getContext());
3131  }
3132  }
3133  }
3134  }
3135 
3136  if (isa<SExtInst>(LHS)) {
3137  // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
3138  // same type.
3139  if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
3140  if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3141  // Compare X and Y. Note that the predicate does not change.
3142  if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
3143  Q, MaxRecurse-1))
3144  return V;
3145  }
3146  // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
3147  // too. If not, then try to deduce the result of the comparison.
3148  else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3149  // Compute the constant that would happen if we truncated to SrcTy then
3150  // reextended to DstTy.
3151  Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3152  Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
3153 
3154  // If the re-extended constant didn't change then this is effectively
3155  // also a case of comparing two sign-extended values.
3156  if (RExt == CI && MaxRecurse)
3157  if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
3158  return V;
3159 
3160  // Otherwise the upper bits of LHS are all equal, while RHS has varying
3161  // bits there. Use this to work out the result of the comparison.
3162  if (RExt != CI) {
3163  switch (Pred) {
3164  default: llvm_unreachable("Unknown ICmp predicate!");
3165  case ICmpInst::ICMP_EQ:
3166  return ConstantInt::getFalse(CI->getContext());
3167  case ICmpInst::ICMP_NE:
3168  return ConstantInt::getTrue(CI->getContext());
3169 
3170  // If RHS is non-negative then LHS <s RHS. If RHS is negative then
3171  // LHS >s RHS.
3172  case ICmpInst::ICMP_SGT:
3173  case ICmpInst::ICMP_SGE:
3174  return CI->getValue().isNegative() ?
3175  ConstantInt::getTrue(CI->getContext()) :
3176  ConstantInt::getFalse(CI->getContext());
3177  case ICmpInst::ICMP_SLT:
3178  case ICmpInst::ICMP_SLE:
3179  return CI->getValue().isNegative() ?
3180  ConstantInt::getFalse(CI->getContext()) :
3181  ConstantInt::getTrue(CI->getContext());
3182 
3183  // If LHS is non-negative then LHS <u RHS. If LHS is negative then
3184  // LHS >u RHS.
3185  case ICmpInst::ICMP_UGT:
3186  case ICmpInst::ICMP_UGE:
3187  // Comparison is true iff the LHS <s 0.
3188  if (MaxRecurse)
3189  if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
3190  Constant::getNullValue(SrcTy),
3191  Q, MaxRecurse-1))
3192  return V;
3193  break;
3194  case ICmpInst::ICMP_ULT:
3195  case ICmpInst::ICMP_ULE:
3196  // Comparison is true iff the LHS >=s 0.
3197  if (MaxRecurse)
3198  if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
3199  Constant::getNullValue(SrcTy),
3200  Q, MaxRecurse-1))
3201  return V;
3202  break;
3203  }
3204  }
3205  }
3206  }
3207  }
3208 
3209  // icmp eq|ne X, Y -> false|true if X != Y
3210  if (ICmpInst::isEquality(Pred) &&
3211  isKnownNonEqual(LHS, RHS, Q.DL, Q.AC, Q.CxtI, Q.DT)) {
3212  return Pred == ICmpInst::ICMP_NE ? getTrue(ITy) : getFalse(ITy);
3213  }
3214 
3215  if (Value *V = simplifyICmpWithBinOp(Pred, LHS, RHS, Q, MaxRecurse))
3216  return V;
3217 
3218  if (Value *V = simplifyICmpWithMinMax(Pred, LHS, RHS, Q, MaxRecurse))
3219  return V;
3220 
3221  // Simplify comparisons of related pointers using a powerful, recursive
3222  // GEP-walk when we have target data available..
3223  if (LHS->getType()->isPointerTy())
3224  if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI, LHS,
3225  RHS))
3226  return C;
3227  if (auto *CLHS = dyn_cast<PtrToIntOperator>(LHS))
3228  if (auto *CRHS = dyn_cast<PtrToIntOperator>(RHS))
3229  if (Q.DL.getTypeSizeInBits(CLHS->getPointerOperandType()) ==
3230  Q.DL.getTypeSizeInBits(CLHS->getType()) &&
3231  Q.DL.getTypeSizeInBits(CRHS->getPointerOperandType()) ==
3232  Q.DL.getTypeSizeInBits(CRHS->getType()))
3233  if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI,
3234  CLHS->getPointerOperand(),
3235  CRHS->getPointerOperand()))
3236  return C;
3237 
3238  if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
3239  if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
3240  if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
3241  GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
3242  (ICmpInst::isEquality(Pred) ||
3243  (GLHS->isInBounds() && GRHS->isInBounds() &&
3244  Pred == ICmpInst::getSignedPredicate(Pred)))) {
3245  // The bases are equal and the indices are constant. Build a constant
3246  // expression GEP with the same indices and a null base pointer to see
3247  // what constant folding can make out of it.
3248  Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
3249  SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
3251  GLHS->getSourceElementType(), Null, IndicesLHS);
3252 
3253  SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
3255  GLHS->getSourceElementType(), Null, IndicesRHS);
3256  return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
3257  }
3258  }
3259  }
3260 
3261  // If the comparison is with the result of a select instruction, check whether
3262  // comparing with either branch of the select always yields the same value.
3263  if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3264  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3265  return V;
3266 
3267  // If the comparison is with the result of a phi instruction, check whether
3268  // doing the compare with each incoming phi value yields a common result.
3269  if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3270  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3271  return V;
3272 
3273  return nullptr;
3274 }
3275 
3276 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3277  const SimplifyQuery &Q) {
3278  return ::SimplifyICmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
3279 }
3280 
3281 /// Given operands for an FCmpInst, see if we can fold the result.
3282 /// If not, this returns null.
3283 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3284  FastMathFlags FMF, const SimplifyQuery &Q,
3285  unsigned MaxRecurse) {
3286  CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3287  assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
3288 
3289  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3290  if (Constant *CRHS = dyn_cast<Constant>(RHS))
3291  return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3292 
3293  // If we have a constant, make sure it is on the RHS.
3294  std::swap(LHS, RHS);
3295  Pred = CmpInst::getSwappedPredicate(Pred);
3296  }
3297 
3298  // Fold trivial predicates.
3299  Type *RetTy = GetCompareTy(LHS);
3300  if (Pred == FCmpInst::FCMP_FALSE)
3301  return getFalse(RetTy);
3302  if (Pred == FCmpInst::FCMP_TRUE)
3303  return getTrue(RetTy);
3304 
3305  // UNO/ORD predicates can be trivially folded if NaNs are ignored.
3306  if (FMF.noNaNs()) {
3307  if (Pred == FCmpInst::FCMP_UNO)
3308  return getFalse(RetTy);
3309  if (Pred == FCmpInst::FCMP_ORD)
3310  return getTrue(RetTy);
3311  }
3312 
3313  // fcmp pred x, undef and fcmp pred undef, x
3314  // fold to true if unordered, false if ordered
3315  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS)) {
3316  // Choosing NaN for the undef will always make unordered comparison succeed
3317  // and ordered comparison fail.
3318  return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred));
3319  }
3320 
3321  // fcmp x,x -> true/false. Not all compares are foldable.
3322  if (LHS == RHS) {
3323  if (CmpInst::isTrueWhenEqual(Pred))
3324  return getTrue(RetTy);
3325  if (CmpInst::isFalseWhenEqual(Pred))
3326  return getFalse(RetTy);
3327  }
3328 
3329  // Handle fcmp with constant RHS
3330  const ConstantFP *CFP = nullptr;
3331  if (const auto *RHSC = dyn_cast<Constant>(RHS)) {
3332  if (RHS->getType()->isVectorTy())
3333  CFP = dyn_cast_or_null<ConstantFP>(RHSC->getSplatValue());
3334  else
3335  CFP = dyn_cast<ConstantFP>(RHSC);
3336  }
3337  if (CFP) {
3338  // If the constant is a nan, see if we can fold the comparison based on it.
3339  if (CFP->getValueAPF().isNaN()) {
3340  if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
3341  return getFalse(RetTy);
3342  assert(FCmpInst::isUnordered(Pred) &&
3343  "Comparison must be either ordered or unordered!");
3344  // True if unordered.
3345  return getTrue(RetTy);
3346  }
3347  // Check whether the constant is an infinity.
3348  if (CFP->getValueAPF().isInfinity()) {
3349  if (CFP->getValueAPF().isNegative()) {
3350  switch (Pred) {
3351  case FCmpInst::FCMP_OLT:
3352  // No value is ordered and less than negative infinity.
3353  return getFalse(RetTy);
3354  case FCmpInst::FCMP_UGE:
3355  // All values are unordered with or at least negative infinity.
3356  return getTrue(RetTy);
3357  default:
3358  break;
3359  }
3360  } else {
3361  switch (Pred) {
3362  case FCmpInst::FCMP_OGT:
3363  // No value is ordered and greater than infinity.
3364  return getFalse(RetTy);
3365  case FCmpInst::FCMP_ULE:
3366  // All values are unordered with and at most infinity.
3367  return getTrue(RetTy);
3368  default:
3369  break;
3370  }
3371  }
3372  }
3373  if (CFP->getValueAPF().isZero()) {
3374  switch (Pred) {
3375  case FCmpInst::FCMP_UGE:
3376  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3377  return getTrue(RetTy);
3378  break;
3379  case FCmpInst::FCMP_OLT:
3380  // X < 0
3381  if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3382  return getFalse(RetTy);
3383  break;
3384  default:
3385  break;
3386  }
3387  }
3388  }
3389 
3390  // If the comparison is with the result of a select instruction, check whether
3391  // comparing with either branch of the select always yields the same value.
3392  if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3393  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3394  return V;
3395 
3396  // If the comparison is with the result of a phi instruction, check whether
3397  // doing the compare with each incoming phi value yields a common result.
3398  if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3399  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3400  return V;
3401 
3402  return nullptr;
3403 }
3404 
3405 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3406  FastMathFlags FMF, const SimplifyQuery &Q) {
3407  return ::SimplifyFCmpInst(Predicate, LHS, RHS, FMF, Q, RecursionLimit);
3408 }
3409 
3410 /// See if V simplifies when its operand Op is replaced with RepOp.
3411 static const Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
3412  const SimplifyQuery &Q,
3413  unsigned MaxRecurse) {
3414  // Trivial replacement.
3415  if (V == Op)
3416  return RepOp;
3417 
3418  // We cannot replace a constant, and shouldn't even try.
3419  if (isa<Constant>(Op))
3420  return nullptr;
3421 
3422  auto *I = dyn_cast<Instruction>(V);
3423  if (!I)
3424  return nullptr;
3425 
3426  // If this is a binary operator, try to simplify it with the replaced op.
3427  if (auto *B = dyn_cast<BinaryOperator>(I)) {
3428  // Consider:
3429  // %cmp = icmp eq i32 %x, 2147483647
3430  // %add = add nsw i32 %x, 1
3431  // %sel = select i1 %cmp, i32 -2147483648, i32 %add
3432  //
3433  // We can't replace %sel with %add unless we strip away the flags.
3434  if (isa<OverflowingBinaryOperator>(B))
3435  if (B->hasNoSignedWrap() || B->hasNoUnsignedWrap())
3436  return nullptr;
3437  if (isa<PossiblyExactOperator>(B))
3438  if (B->isExact())
3439  return nullptr;
3440 
3441  if (MaxRecurse) {
3442  if (B->getOperand(0) == Op)
3443  return SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), Q,
3444  MaxRecurse - 1);
3445  if (B->getOperand(1) == Op)
3446  return SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, Q,
3447  MaxRecurse - 1);
3448  }
3449  }
3450 
3451  // Same for CmpInsts.
3452  if (CmpInst *C = dyn_cast<CmpInst>(I)) {
3453  if (MaxRecurse) {
3454  if (C->getOperand(0) == Op)
3455  return SimplifyCmpInst(C->getPredicate(), RepOp, C->getOperand(1), Q,
3456  MaxRecurse - 1);
3457  if (C->getOperand(1) == Op)
3458  return SimplifyCmpInst(C->getPredicate(), C->getOperand(0), RepOp, Q,
3459  MaxRecurse - 1);
3460  }
3461  }
3462 
3463  // TODO: We could hand off more cases to instsimplify here.
3464 
3465  // If all operands are constant after substituting Op for RepOp then we can
3466  // constant fold the instruction.
3467  if (Constant *CRepOp = dyn_cast<Constant>(RepOp)) {
3468  // Build a list of all constant operands.
3469  SmallVector<Constant *, 8> ConstOps;
3470  for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
3471  if (I->getOperand(i) == Op)
3472  ConstOps.push_back(CRepOp);
3473  else if (Constant *COp = dyn_cast<Constant>(I->getOperand(i)))
3474  ConstOps.push_back(COp);
3475  else
3476  break;
3477  }
3478 
3479  // All operands were constants, fold it.
3480  if (ConstOps.size() == I->getNumOperands()) {
3481  if (CmpInst *C = dyn_cast<CmpInst>(I))
3482  return ConstantFoldCompareInstOperands(C->getPredicate(), ConstOps[0],
3483  ConstOps[1], Q.DL, Q.TLI);
3484 
3485  if (LoadInst *LI = dyn_cast<LoadInst>(I))
3486  if (!LI->isVolatile())
3487  return ConstantFoldLoadFromConstPtr(ConstOps[0], LI->getType(), Q.DL);
3488 
3489  return ConstantFoldInstOperands(I, ConstOps, Q.DL, Q.TLI);
3490  }
3491  }
3492 
3493  return nullptr;
3494 }
3495 
3496 /// Try to simplify a select instruction when its condition operand is an
3497 /// integer comparison where one operand of the compare is a constant.
3498 static Value *simplifySelectBitTest(Value *TrueVal, Value *FalseVal, Value *X,
3499  const APInt *Y, bool TrueWhenUnset) {
3500  const APInt *C;
3501 
3502  // (X & Y) == 0 ? X & ~Y : X --> X
3503  // (X & Y) != 0 ? X & ~Y : X --> X & ~Y
3504  if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) &&
3505  *Y == ~*C)
3506  return TrueWhenUnset ? FalseVal : TrueVal;
3507 
3508  // (X & Y) == 0 ? X : X & ~Y --> X & ~Y
3509  // (X & Y) != 0 ? X : X & ~Y --> X
3510  if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) &&
3511  *Y == ~*C)
3512  return TrueWhenUnset ? FalseVal : TrueVal;
3513 
3514  if (Y->isPowerOf2()) {
3515  // (X & Y) == 0 ? X | Y : X --> X | Y
3516  // (X & Y) != 0 ? X | Y : X --> X
3517  if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) &&
3518  *Y == *C)
3519  return TrueWhenUnset ? TrueVal : FalseVal;
3520 
3521  // (X & Y) == 0 ? X : X | Y --> X
3522  // (X & Y) != 0 ? X : X | Y --> X | Y
3523  if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) &&
3524  *Y == *C)
3525  return TrueWhenUnset ? TrueVal : FalseVal;
3526  }
3527 
3528  return nullptr;
3529 }
3530 
3531 /// An alternative way to test if a bit is set or not uses sgt/slt instead of
3532 /// eq/ne.
3534  ICmpInst::Predicate Pred,
3535  Value *TrueVal, Value *FalseVal) {
3536  Value *X;
3537  APInt Mask;
3538  if (!decomposeBitTestICmp(CmpLHS, CmpRHS, Pred, X, Mask))
3539  return nullptr;
3540 
3541  return simplifySelectBitTest(TrueVal, FalseVal, X, &Mask,
3542  Pred == ICmpInst::ICMP_EQ);
3543 }
3544 
3545 /// Try to simplify a select instruction when its condition operand is an
3546 /// integer comparison.
3547 static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
3548  Value *FalseVal, const SimplifyQuery &Q,
3549  unsigned MaxRecurse) {
3550  ICmpInst::Predicate Pred;
3551  Value *CmpLHS, *CmpRHS;
3552  if (!match(CondVal, m_ICmp(Pred, m_Value(CmpLHS), m_Value(CmpRHS))))
3553  return nullptr;
3554 
3555  if (ICmpInst::isEquality(Pred) && match(CmpRHS, m_Zero())) {
3556  Value *X;
3557  const APInt *Y;
3558  if (match(CmpLHS, m_And(m_Value(X), m_APInt(Y))))
3559  if (Value *V = simplifySelectBitTest(TrueVal, FalseVal, X, Y,
3560  Pred == ICmpInst::ICMP_EQ))
3561  return V;
3562  }
3563 
3564  // Check for other compares that behave like bit test.
3565  if (Value *V = simplifySelectWithFakeICmpEq(CmpLHS, CmpRHS, Pred,
3566  TrueVal, FalseVal))
3567  return V;
3568 
3569  if (CondVal->hasOneUse()) {
3570  const APInt *C;
3571  if (match(CmpRHS, m_APInt(C))) {
3572  // X < MIN ? T : F --> F
3573  if (Pred == ICmpInst::ICMP_SLT && C->isMinSignedValue())
3574  return FalseVal;
3575  // X < MIN ? T : F --> F
3576  if (Pred == ICmpInst::ICMP_ULT && C->isMinValue())
3577  return FalseVal;
3578  // X > MAX ? T : F --> F
3579  if (Pred == ICmpInst::ICMP_SGT && C->isMaxSignedValue())
3580  return FalseVal;
3581  // X > MAX ? T : F --> F
3582  if (Pred == ICmpInst::ICMP_UGT && C->isMaxValue())
3583  return FalseVal;
3584  }
3585  }
3586 
3587  // If we have an equality comparison, then we know the value in one of the
3588  // arms of the select. See if substituting this value into the arm and
3589  // simplifying the result yields the same value as the other arm.
3590  if (Pred == ICmpInst::ICMP_EQ) {
3591  if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3592  TrueVal ||
3593  SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3594  TrueVal)
3595  return FalseVal;
3596  if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3597  FalseVal ||
3598  SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3599  FalseVal)
3600  return FalseVal;
3601  } else if (Pred == ICmpInst::ICMP_NE) {
3602  if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3603  FalseVal ||
3604  SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3605  FalseVal)
3606  return TrueVal;
3607  if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3608  TrueVal ||
3609  SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3610  TrueVal)
3611  return TrueVal;
3612  }
3613 
3614  return nullptr;
3615 }
3616 
3617 /// Given operands for a SelectInst, see if we can fold the result.
3618 /// If not, this returns null.
3619 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
3620  Value *FalseVal, const SimplifyQuery &Q,
3621  unsigned MaxRecurse) {
3622  // select true, X, Y -> X
3623  // select false, X, Y -> Y
3624  if (Constant *CB = dyn_cast<Constant>(CondVal)) {
3625  if (Constant *CT = dyn_cast<Constant>(TrueVal))
3626  if (Constant *CF = dyn_cast<Constant>(FalseVal))
3627  return ConstantFoldSelectInstruction(CB, CT, CF);
3628  if (CB->isAllOnesValue())
3629  return TrueVal;
3630  if (CB->isNullValue())
3631  return FalseVal;
3632  }
3633 
3634  // select C, X, X -> X
3635  if (TrueVal == FalseVal)
3636  return TrueVal;
3637 
3638  if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
3639  if (isa<Constant>(FalseVal))
3640  return FalseVal;
3641  return TrueVal;
3642  }
3643  if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
3644  return FalseVal;
3645  if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
3646  return TrueVal;
3647 
3648  if (Value *V =
3649  simplifySelectWithICmpCond(CondVal, TrueVal, FalseVal, Q, MaxRecurse))
3650  return V;
3651 
3652  return nullptr;
3653 }
3654 
3655 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3656  const SimplifyQuery &Q) {
3657  return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Q, RecursionLimit);
3658 }
3659 
3660 /// Given operands for an GetElementPtrInst, see if we can fold the result.
3661 /// If not, this returns null.
3663  const SimplifyQuery &Q, unsigned) {
3664  // The type of the GEP pointer operand.
3665  unsigned AS =
3666  cast<PointerType>(Ops[0]->getType()->getScalarType())->getAddressSpace();
3667 
3668  // getelementptr P -> P.
3669  if (Ops.size() == 1)
3670  return Ops[0];
3671 
3672  // Compute the (pointer) type returned by the GEP instruction.
3673  Type *LastType = GetElementPtrInst::getIndexedType(SrcTy, Ops.slice(1));
3674  Type *GEPTy = PointerType::get(LastType, AS);
3675  if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
3676  GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3677  else if (VectorType *VT = dyn_cast<VectorType>(Ops[1]->getType()))
3678  GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3679 
3680  if (isa<UndefValue>(Ops[0]))
3681  return UndefValue::get(GEPTy);
3682 
3683  if (Ops.size() == 2) {
3684  // getelementptr P, 0 -> P.
3685  if (match(Ops[1], m_Zero()))
3686  return Ops[0];
3687 
3688  Type *Ty = SrcTy;
3689  if (Ty->isSized()) {
3690  Value *P;
3691  uint64_t C;
3692  uint64_t TyAllocSize = Q.DL.getTypeAllocSize(Ty);
3693  // getelementptr P, N -> P if P points to a type of zero size.
3694  if (TyAllocSize == 0)
3695  return Ops[0];
3696 
3697  // The following transforms are only safe if the ptrtoint cast
3698  // doesn't truncate the pointers.
3699  if (Ops[1]->getType()->getScalarSizeInBits() ==
3700  Q.DL.getPointerSizeInBits(AS)) {
3701  auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
3702  if (match(P, m_Zero()))
3703  return Constant::getNullValue(GEPTy);
3704  Value *Temp;
3705  if (match(P, m_PtrToInt(m_Value(Temp))))
3706  if (Temp->getType() == GEPTy)
3707  return Temp;
3708  return nullptr;
3709  };
3710 
3711  // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
3712  if (TyAllocSize == 1 &&
3713  match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
3714  if (Value *R = PtrToIntOrZero(P))
3715  return R;
3716 
3717  // getelementptr V, (ashr (sub P, V), C) -> Q
3718  // if P points to a type of size 1 << C.
3719  if (match(Ops[1],
3720  m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3721  m_ConstantInt(C))) &&
3722  TyAllocSize == 1ULL << C)
3723  if (Value *R = PtrToIntOrZero(P))
3724  return R;
3725 
3726  // getelementptr V, (sdiv (sub P, V), C) -> Q
3727  // if P points to a type of size C.
3728  if (match(Ops[1],
3729  m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3730  m_SpecificInt(TyAllocSize))))
3731  if (Value *R = PtrToIntOrZero(P))
3732  return R;
3733  }
3734  }
3735  }
3736 
3737  if (Q.DL.getTypeAllocSize(LastType) == 1 &&
3738  all_of(Ops.slice(1).drop_back(1),
3739  [](Value *Idx) { return match(Idx, m_Zero()); })) {
3740  unsigned PtrWidth =
3741  Q.DL.getPointerSizeInBits(Ops[0]->getType()->getPointerAddressSpace());
3742  if (Q.DL.getTypeSizeInBits(Ops.back()->getType()) == PtrWidth) {
3743  APInt BasePtrOffset(PtrWidth, 0);
3744  Value *StrippedBasePtr =
3745  Ops[0]->stripAndAccumulateInBoundsConstantOffsets(Q.DL,
3746  BasePtrOffset);
3747 
3748  // gep (gep V, C), (sub 0, V) -> C
3749  if (match(Ops.back(),
3750  m_Sub(m_Zero(), m_PtrToInt(m_Specific(StrippedBasePtr))))) {
3751  auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset);
3752  return ConstantExpr::getIntToPtr(CI, GEPTy);
3753  }
3754  // gep (gep V, C), (xor V, -1) -> C-1
3755  if (match(Ops.back(),
3756  m_Xor(m_PtrToInt(m_Specific(StrippedBasePtr)), m_AllOnes()))) {
3757  auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset - 1);
3758  return ConstantExpr::getIntToPtr(CI, GEPTy);
3759  }
3760  }
3761  }
3762 
3763  // Check to see if this is constant foldable.
3764  if (!all_of(Ops, [](Value *V) { return isa<Constant>(V); }))
3765  return nullptr;
3766 
3767  auto *CE = ConstantExpr::getGetElementPtr(SrcTy, cast<Constant>(Ops[0]),
3768  Ops.slice(1));
3769  if (auto *CEFolded = ConstantFoldConstant(CE, Q.DL))
3770  return CEFolded;
3771  return CE;
3772 }
3773 
3775  const SimplifyQuery &Q) {
3776  return ::SimplifyGEPInst(SrcTy, Ops, Q, RecursionLimit);
3777 }
3778 
3779 /// Given operands for an InsertValueInst, see if we can fold the result.
3780 /// If not, this returns null.
3782  ArrayRef<unsigned> Idxs, const SimplifyQuery &Q,
3783  unsigned) {
3784  if (Constant *CAgg = dyn_cast<Constant>(Agg))
3785  if (Constant *CVal = dyn_cast<Constant>(Val))
3786  return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
3787 
3788  // insertvalue x, undef, n -> x
3789  if (match(Val, m_Undef()))
3790  return Agg;
3791 
3792  // insertvalue x, (extractvalue y, n), n
3793  if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
3794  if (EV->getAggregateOperand()->getType() == Agg->getType() &&
3795  EV->getIndices() == Idxs) {
3796  // insertvalue undef, (extractvalue y, n), n -> y
3797  if (match(Agg, m_Undef()))
3798  return EV->getAggregateOperand();
3799 
3800  // insertvalue y, (extractvalue y, n), n -> y
3801  if (Agg == EV->getAggregateOperand())
3802  return Agg;
3803  }
3804 
3805  return nullptr;
3806 }
3807 
3809  ArrayRef<unsigned> Idxs,
3810  const SimplifyQuery &Q) {
3812 }
3813 
3814 /// Given operands for an ExtractValueInst, see if we can fold the result.
3815 /// If not, this returns null.
3817  const SimplifyQuery &, unsigned) {
3818  if (auto *CAgg = dyn_cast<Constant>(Agg))
3819  return ConstantFoldExtractValueInstruction(CAgg, Idxs);
3820 
3821  // extractvalue x, (insertvalue y, elt, n), n -> elt
3822  unsigned NumIdxs = Idxs.size();
3823  for (auto *IVI = dyn_cast<InsertValueInst>(Agg); IVI != nullptr;
3824  IVI = dyn_cast<InsertValueInst>(IVI->getAggregateOperand())) {
3825  ArrayRef<unsigned> InsertValueIdxs = IVI->getIndices();
3826  unsigned NumInsertValueIdxs = InsertValueIdxs.size();
3827  unsigned NumCommonIdxs = std::min(NumInsertValueIdxs, NumIdxs);
3828  if (InsertValueIdxs.slice(0, NumCommonIdxs) ==
3829  Idxs.slice(0, NumCommonIdxs)) {
3830  if (NumIdxs == NumInsertValueIdxs)
3831  return IVI->getInsertedValueOperand();
3832  break;
3833  }
3834  }
3835 
3836  return nullptr;
3837 }
3838 
3840  const SimplifyQuery &Q) {
3842 }
3843 
3844 /// Given operands for an ExtractElementInst, see if we can fold the result.
3845 /// If not, this returns null.
3847  unsigned) {
3848  if (auto *CVec = dyn_cast<Constant>(Vec)) {
3849  if (auto *CIdx = dyn_cast<Constant>(Idx))
3850  return ConstantFoldExtractElementInstruction(CVec, CIdx);
3851 
3852  // The index is not relevant if our vector is a splat.
3853  if (auto *Splat = CVec->getSplatValue())
3854  return Splat;
3855 
3856  if (isa<UndefValue>(Vec))
3857  return UndefValue::get(Vec->getType()->getVectorElementType());
3858  }
3859 
3860  // If extracting a specified index from the vector, see if we can recursively
3861  // find a previously computed scalar that was inserted into the vector.
3862  if (auto *IdxC = dyn_cast<ConstantInt>(Idx))
3863  if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue()))
3864  return Elt;
3865 
3866  return nullptr;
3867 }
3868 
3870  const SimplifyQuery &Q) {
3872 }
3873 
3874 /// See if we can fold the given phi. If not, returns null.
3875 static Value *SimplifyPHINode(PHINode *PN, const SimplifyQuery &Q) {
3876  // If all of the PHI's incoming values are the same then replace the PHI node
3877  // with the common value.
3878  Value *CommonValue = nullptr;
3879  bool HasUndefInput = false;
3880  for (Value *Incoming : PN->incoming_values()) {
3881  // If the incoming value is the phi node itself, it can safely be skipped.
3882  if (Incoming == PN) continue;
3883  if (isa<UndefValue>(Incoming)) {
3884  // Remember that we saw an undef value, but otherwise ignore them.
3885  HasUndefInput = true;
3886  continue;
3887  }
3888  if (CommonValue && Incoming != CommonValue)
3889  return nullptr; // Not the same, bail out.
3890  CommonValue = Incoming;
3891  }
3892 
3893  // If CommonValue is null then all of the incoming values were either undef or
3894  // equal to the phi node itself.
3895  if (!CommonValue)
3896  return UndefValue::get(PN->getType());
3897 
3898  // If we have a PHI node like phi(X, undef, X), where X is defined by some
3899  // instruction, we cannot return X as the result of the PHI node unless it
3900  // dominates the PHI block.
3901  if (HasUndefInput)
3902  return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
3903 
3904  return CommonValue;
3905 }
3906 
3907 static Value *SimplifyCastInst(unsigned CastOpc, Value *Op,
3908  Type *Ty, const SimplifyQuery &Q, unsigned MaxRecurse) {
3909  if (auto *C = dyn_cast<Constant>(Op))
3910  return ConstantFoldCastOperand(CastOpc, C, Ty, Q.DL);
3911 
3912  if (auto *CI = dyn_cast<CastInst>(Op)) {
3913  auto *Src = CI->getOperand(0);
3914  Type *SrcTy = Src->getType();
3915  Type *MidTy = CI->getType();
3916  Type *DstTy = Ty;
3917  if (Src->getType() == Ty) {
3918  auto FirstOp = static_cast<Instruction::CastOps>(CI->getOpcode());
3919  auto SecondOp = static_cast<Instruction::CastOps>(CastOpc);
3920  Type *SrcIntPtrTy =
3921  SrcTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(SrcTy) : nullptr;
3922  Type *MidIntPtrTy =
3923  MidTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(MidTy) : nullptr;
3924  Type *DstIntPtrTy =
3925  DstTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(DstTy) : nullptr;
3926  if (CastInst::isEliminableCastPair(FirstOp, SecondOp, SrcTy, MidTy, DstTy,
3927  SrcIntPtrTy, MidIntPtrTy,
3928  DstIntPtrTy) == Instruction::BitCast)
3929  return Src;
3930  }
3931  }
3932 
3933  // bitcast x -> x
3934  if (CastOpc == Instruction::BitCast)
3935  if (Op->getType() == Ty)
3936  return Op;
3937 
3938  return nullptr;
3939 }
3940 
3941 Value *llvm::SimplifyCastInst(unsigned CastOpc, Value *Op, Type *Ty,
3942  const SimplifyQuery &Q) {
3943  return ::SimplifyCastInst(CastOpc, Op, Ty, Q, RecursionLimit);
3944 }
3945 
3946 /// For the given destination element of a shuffle, peek through shuffles to
3947 /// match a root vector source operand that contains that element in the same
3948 /// vector lane (ie, the same mask index), so we can eliminate the shuffle(s).
3949 static Value *foldIdentityShuffles(int DestElt, Value *Op0, Value *Op1,
3950  int MaskVal, Value *RootVec,
3951  unsigned MaxRecurse) {
3952  if (!MaxRecurse--)
3953  return nullptr;
3954 
3955  // Bail out if any mask value is undefined. That kind of shuffle may be
3956  // simplified further based on demanded bits or other folds.
3957  if (MaskVal == -1)
3958  return nullptr;
3959 
3960  // The mask value chooses which source operand we need to look at next.
3961  int InVecNumElts = Op0->getType()->getVectorNumElements();
3962  int RootElt = MaskVal;
3963  Value *SourceOp = Op0;
3964  if (MaskVal >= InVecNumElts) {
3965  RootElt = MaskVal - InVecNumElts;
3966  SourceOp = Op1;
3967  }
3968 
3969  // If the source operand is a shuffle itself, look through it to find the
3970  // matching root vector.
3971  if (auto *SourceShuf = dyn_cast<ShuffleVectorInst>(SourceOp)) {
3972  return foldIdentityShuffles(
3973  DestElt, SourceShuf->getOperand(0), SourceShuf->getOperand(1),
3974  SourceShuf->getMaskValue(RootElt), RootVec, MaxRecurse);
3975  }
3976 
3977  // TODO: Look through bitcasts? What if the bitcast changes the vector element
3978  // size?
3979 
3980  // The source operand is not a shuffle. Initialize the root vector value for
3981  // this shuffle if that has not been done yet.
3982  if (!RootVec)
3983  RootVec = SourceOp;
3984 
3985  // Give up as soon as a source operand does not match the existing root value.
3986  if (RootVec != SourceOp)
3987  return nullptr;
3988 
3989  // The element must be coming from the same lane in the source vector
3990  // (although it may have crossed lanes in intermediate shuffles).
3991  if (RootElt != DestElt)
3992  return nullptr;
3993 
3994  return RootVec;
3995 }
3996 
3998  Type *RetTy, const SimplifyQuery &Q,
3999  unsigned MaxRecurse) {
4000  if (isa<UndefValue>(Mask))
4001  return UndefValue::get(RetTy);
4002 
4003  Type *InVecTy = Op0->getType();
4004  unsigned MaskNumElts = Mask->getType()->getVectorNumElements();
4005  unsigned InVecNumElts = InVecTy->getVectorNumElements();
4006 
4007  SmallVector<int, 32> Indices;
4008  ShuffleVectorInst::getShuffleMask(Mask, Indices);
4009  assert(MaskNumElts == Indices.size() &&
4010  "Size of Indices not same as number of mask elements?");
4011 
4012  // Canonicalization: If mask does not select elements from an input vector,
4013  // replace that input vector with undef.
4014  bool MaskSelects0 = false, MaskSelects1 = false;
4015  for (unsigned i = 0; i != MaskNumElts; ++i) {
4016  if (Indices[i] == -1)
4017  continue;
4018  if ((unsigned)Indices[i] < InVecNumElts)
4019  MaskSelects0 = true;
4020  else
4021  MaskSelects1 = true;
4022  }
4023  if (!MaskSelects0)
4024  Op0 = UndefValue::get(InVecTy);
4025  if (!MaskSelects1)
4026  Op1 = UndefValue::get(InVecTy);
4027 
4028  auto *Op0Const = dyn_cast<Constant>(Op0);
4029  auto *Op1Const = dyn_cast<Constant>(Op1);
4030 
4031  // If all operands are constant, constant fold the shuffle.
4032  if (Op0Const && Op1Const)
4033  return ConstantFoldShuffleVectorInstruction(Op0Const, Op1Const, Mask);
4034 
4035  // Canonicalization: if only one input vector is constant, it shall be the
4036  // second one.
4037  if (Op0Const && !Op1Const) {
4038  std::swap(Op0, Op1);
4039  ShuffleVectorInst::commuteShuffleMask(Indices, InVecNumElts);
4040  }
4041 
4042  // A shuffle of a splat is always the splat itself. Legal if the shuffle's
4043  // value type is same as the input vectors' type.
4044  if (auto *OpShuf = dyn_cast<ShuffleVectorInst>(Op0))
4045  if (isa<UndefValue>(Op1) && RetTy == InVecTy &&
4046  OpShuf->getMask()->getSplatValue())
4047  return Op0;
4048 
4049  // Don't fold a shuffle with undef mask elements. This may get folded in a
4050  // better way using demanded bits or other analysis.
4051  // TODO: Should we allow this?
4052  if (find(Indices, -1) != Indices.end())
4053  return nullptr;
4054 
4055  // Check if every element of this shuffle can be mapped back to the
4056  // corresponding element of a single root vector. If so, we don't need this
4057  // shuffle. This handles simple identity shuffles as well as chains of
4058  // shuffles that may widen/narrow and/or move elements across lanes and back.
4059  Value *RootVec = nullptr;
4060  for (unsigned i = 0; i != MaskNumElts; ++i) {
4061  // Note that recursion is limited for each vector element, so if any element
4062  // exceeds the limit, this will fail to simplify.
4063  RootVec =
4064  foldIdentityShuffles(i, Op0, Op1, Indices[i], RootVec, MaxRecurse);
4065 
4066  // We can't replace a widening/narrowing shuffle with one of its operands.
4067  if (!RootVec || RootVec->getType() != RetTy)
4068  return nullptr;
4069  }
4070  return RootVec;
4071 }
4072 
4073 /// Given operands for a ShuffleVectorInst, fold the result or return null.
4075  Type *RetTy, const SimplifyQuery &Q) {
4076  return ::SimplifyShuffleVectorInst(Op0, Op1, Mask, RetTy, Q, RecursionLimit);
4077 }
4078 
4079 /// Given operands for an FAdd, see if we can fold the result. If not, this
4080 /// returns null.
4082  const SimplifyQuery &Q, unsigned MaxRecurse) {
4083  if (Constant *C = foldOrCommuteConstant(Instruction::FAdd, Op0, Op1, Q))
4084  return C;
4085 
4086  // fadd X, -0 ==> X
4087  if (match(Op1, m_NegZero()))
4088  return Op0;
4089 
4090  // fadd X, 0 ==> X, when we know X is not -0
4091  if (match(Op1, m_Zero()) &&
4092  (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
4093  return Op0;
4094 
4095  // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
4096  // where nnan and ninf have to occur at least once somewhere in this
4097  // expression
4098  Value *SubOp = nullptr;
4099  if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
4100  SubOp = Op1;
4101  else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
4102  SubOp = Op0;
4103  if (SubOp) {
4104  Instruction *FSub = cast<Instruction>(SubOp);
4105  if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
4106  (FMF.noInfs() || FSub->hasNoInfs()))
4107  return Constant::getNullValue(Op0->getType());
4108  }
4109 
4110  return nullptr;
4111 }
4112 
4113 /// Given operands for an FSub, see if we can fold the result. If not, this
4114 /// returns null.
4116  const SimplifyQuery &Q, unsigned MaxRecurse) {
4117  if (Constant *C = foldOrCommuteConstant(Instruction::FSub, Op0, Op1, Q))
4118  return C;
4119 
4120  // fsub X, 0 ==> X
4121  if (match(Op1, m_Zero()))
4122  return Op0;
4123 
4124  // fsub X, -0 ==> X, when we know X is not -0
4125  if (match(Op1, m_NegZero()) &&
4126  (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
4127  return Op0;
4128 
4129  // fsub -0.0, (fsub -0.0, X) ==> X
4130  Value *X;
4131  if (match(Op0, m_NegZero()) && match(Op1, m_FSub(m_NegZero(), m_Value(X))))
4132  return X;
4133 
4134  // fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored.
4135  if (FMF.noSignedZeros() && match(Op0, m_AnyZero()) &&
4136  match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
4137  return X;
4138 
4139  // fsub nnan x, x ==> 0.0
4140  if (FMF.noNaNs() && Op0 == Op1)
4141  return Constant::getNullValue(Op0->getType());
4142 
4143  return nullptr;
4144 }
4145 
4146 /// Given the operands for an FMul, see if we can fold the result
4148  const SimplifyQuery &Q, unsigned MaxRecurse) {
4149  if (Constant *C = foldOrCommuteConstant(Instruction::FMul, Op0, Op1, Q))
4150  return C;
4151 
4152  // fmul X, 1.0 ==> X
4153  if (match(Op1, m_FPOne()))
4154  return Op0;
4155 
4156  // fmul nnan nsz X, 0 ==> 0
4157  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
4158  return Op1;
4159 
4160  return nullptr;
4161 }
4162 
4164  const SimplifyQuery &Q) {
4165  return ::SimplifyFAddInst(Op0, Op1, FMF, Q, RecursionLimit);
4166 }
4167 
4168 
4170  const SimplifyQuery &Q) {
4171  return ::SimplifyFSubInst(Op0, Op1, FMF, Q, RecursionLimit);
4172 }
4173 
4175  const SimplifyQuery &Q) {
4176  return ::SimplifyFMulInst(Op0, Op1, FMF, Q, RecursionLimit);
4177 }
4178 
4180  const SimplifyQuery &Q, unsigned) {
4181  if (Constant *C = foldOrCommuteConstant(Instruction::FDiv, Op0, Op1, Q))
4182  return C;
4183 
4184  // undef / X -> undef (the undef could be a snan).
4185  if (match(Op0, m_Undef()))
4186  return Op0;
4187 
4188  // X / undef -> undef
4189  if (match(Op1, m_Undef()))
4190  return Op1;
4191 
4192  // X / 1.0 -> X
4193  if (match(Op1, m_FPOne()))
4194  return Op0;
4195 
4196  // 0 / X -> 0
4197  // Requires that NaNs are off (X could be zero) and signed zeroes are
4198  // ignored (X could be positive or negative, so the output sign is unknown).
4199  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZero()))
4200  return Op0;
4201 
4202  if (FMF.noNaNs()) {
4203  // X / X -> 1.0 is legal when NaNs are ignored.
4204  if (Op0 == Op1)
4205  return ConstantFP::get(Op0->getType(), 1.0);
4206 
4207  // -X / X -> -1.0 and
4208  // X / -X -> -1.0 are legal when NaNs are ignored.
4209  // We can ignore signed zeros because +-0.0/+-0.0 is NaN and ignored.
4210  if ((BinaryOperator::isFNeg(Op0, /*IgnoreZeroSign=*/true) &&
4211  BinaryOperator::getFNegArgument(Op0) == Op1) ||
4212  (BinaryOperator::isFNeg(Op1, /*IgnoreZeroSign=*/true) &&
4213  BinaryOperator::getFNegArgument(Op1) == Op0))
4214  return ConstantFP::get(Op0->getType(), -1.0);
4215  }
4216 
4217  return nullptr;
4218 }
4219 
4221  const SimplifyQuery &Q) {
4222  return ::SimplifyFDivInst(Op0, Op1, FMF, Q, RecursionLimit);
4223 }
4224 
4226  const SimplifyQuery &Q, unsigned) {
4227  if (Constant *C = foldOrCommuteConstant(Instruction::FRem, Op0, Op1, Q))
4228  return C;
4229 
4230  // undef % X -> undef (the undef could be a snan).
4231  if (match(Op0, m_Undef()))
4232  return Op0;
4233 
4234  // X % undef -> undef
4235  if (match(Op1, m_Undef()))
4236  return Op1;
4237 
4238  // 0 % X -> 0
4239  // Requires that NaNs are off (X could be zero) and signed zeroes are
4240  // ignored (X could be positive or negative, so the output sign is unknown).
4241  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZero()))
4242  return Op0;
4243 
4244  return nullptr;
4245 }
4246 
4248  const SimplifyQuery &Q) {
4249  return ::SimplifyFRemInst(Op0, Op1, FMF, Q, RecursionLimit);
4250 }
4251 
4252 //=== Helper functions for higher up the class hierarchy.
4253 
4254 /// Given operands for a BinaryOperator, see if we can fold the result.
4255 /// If not, this returns null.
4256 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4257  const SimplifyQuery &Q, unsigned MaxRecurse) {
4258  switch (Opcode) {
4259  case Instruction::Add:
4260  return SimplifyAddInst(LHS, RHS, false, false, Q, MaxRecurse);
4261  case Instruction::Sub:
4262  return SimplifySubInst(LHS, RHS, false, false, Q, MaxRecurse);
4263  case Instruction::Mul:
4264  return SimplifyMulInst(LHS, RHS, Q, MaxRecurse);
4265  case Instruction::SDiv:
4266  return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
4267  case Instruction::UDiv:
4268  return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
4269  case Instruction::SRem:
4270  return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
4271  case Instruction::URem:
4272  return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
4273  case Instruction::Shl:
4274  return SimplifyShlInst(LHS, RHS, false, false, Q, MaxRecurse);
4275  case Instruction::LShr:
4276  return SimplifyLShrInst(LHS, RHS, false, Q, MaxRecurse);
4277  case Instruction::AShr:
4278  return SimplifyAShrInst(LHS, RHS, false, Q, MaxRecurse);
4279  case Instruction::And:
4280  return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
4281  case Instruction::Or:
4282  return SimplifyOrInst(LHS, RHS, Q, MaxRecurse);
4283  case Instruction::Xor:
4284  return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
4285  case Instruction::FAdd:
4286  return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4287  case Instruction::FSub:
4288  return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4289  case Instruction::FMul:
4290  return SimplifyFMulInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4291  case Instruction::FDiv:
4292  return SimplifyFDivInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4293  case Instruction::FRem:
4294  return SimplifyFRemInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4295  default:
4296  llvm_unreachable("Unexpected opcode");
4297  }
4298 }
4299 
4300 /// Given operands for a BinaryOperator, see if we can fold the result.
4301 /// If not, this returns null.
4302 /// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the
4303 /// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp.
4304 static Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4305  const FastMathFlags &FMF, const SimplifyQuery &Q,
4306  unsigned MaxRecurse) {
4307  switch (Opcode) {
4308  case Instruction::FAdd:
4309  return SimplifyFAddInst(LHS, RHS, FMF, Q, MaxRecurse);
4310  case Instruction::FSub:
4311  return SimplifyFSubInst(LHS, RHS, FMF, Q, MaxRecurse);
4312  case Instruction::FMul:
4313  return SimplifyFMulInst(LHS, RHS, FMF, Q, MaxRecurse);
4314  case Instruction::FDiv:
4315  return SimplifyFDivInst(LHS, RHS, FMF, Q, MaxRecurse);
4316  default:
4317  return SimplifyBinOp(Opcode, LHS, RHS, Q, MaxRecurse);
4318  }
4319 }
4320 
4321 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4322  const SimplifyQuery &Q) {
4323  return ::SimplifyBinOp(Opcode, LHS, RHS, Q, RecursionLimit);
4324 }
4325 
4326 Value *llvm::SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4327  FastMathFlags FMF, const SimplifyQuery &Q) {
4328  return ::SimplifyFPBinOp(Opcode, LHS, RHS, FMF, Q, RecursionLimit);
4329 }
4330 
4331 /// Given operands for a CmpInst, see if we can fold the result.
4332 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
4333  const SimplifyQuery &Q, unsigned MaxRecurse) {
4335  return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
4336  return SimplifyFCmpInst(Predicate, LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4337 }
4338 
4339 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
4340  const SimplifyQuery &Q) {
4341  return ::SimplifyCmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
4342 }
4343 
4345  switch (ID) {
4346  default: return false;
4347 
4348  // Unary idempotent: f(f(x)) = f(x)
4349  case Intrinsic::fabs:
4350  case Intrinsic::floor:
4351  case Intrinsic::ceil:
4352  case Intrinsic::trunc:
4353  case Intrinsic::rint:
4354  case Intrinsic::nearbyint:
4355  case Intrinsic::round:
4356  case Intrinsic::canonicalize:
4357  return true;
4358  }
4359 }
4360 
4362  const DataLayout &DL) {
4363  GlobalValue *PtrSym;
4364  APInt PtrOffset;
4365  if (!IsConstantOffsetFromGlobal(Ptr, PtrSym, PtrOffset, DL))
4366  return nullptr;
4367 
4368  Type *Int8PtrTy = Type::getInt8PtrTy(Ptr->getContext());
4370  Type *Int32PtrTy = Int32Ty->getPointerTo();
4371  Type *Int64Ty = Type::getInt64Ty(Ptr->getContext());
4372 
4373  auto *OffsetConstInt = dyn_cast<ConstantInt>(Offset);
4374  if (!OffsetConstInt || OffsetConstInt->getType()->getBitWidth() > 64)
4375  return nullptr;
4376 
4377  uint64_t OffsetInt = OffsetConstInt->getSExtValue();
4378  if (OffsetInt % 4 != 0)
4379  return nullptr;
4380 
4382  Int32Ty, ConstantExpr::getBitCast(Ptr, Int32PtrTy),
4383  ConstantInt::get(Int64Ty, OffsetInt / 4));
4384  Constant *Loaded = ConstantFoldLoadFromConstPtr(C, Int32Ty, DL);
4385  if (!Loaded)
4386  return nullptr;
4387 
4388  auto *LoadedCE = dyn_cast<ConstantExpr>(Loaded);
4389  if (!LoadedCE)
4390  return nullptr;
4391 
4392  if (LoadedCE->getOpcode() == Instruction::Trunc) {
4393  LoadedCE = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4394  if (!LoadedCE)
4395  return nullptr;
4396  }
4397 
4398  if (LoadedCE->getOpcode() != Instruction::Sub)
4399  return nullptr;
4400 
4401  auto *LoadedLHS = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4402  if (!LoadedLHS || LoadedLHS->getOpcode() != Instruction::PtrToInt)
4403  return nullptr;
4404  auto *LoadedLHSPtr = LoadedLHS->getOperand(0);
4405 
4406  Constant *LoadedRHS = LoadedCE->getOperand(1);
4407  GlobalValue *LoadedRHSSym;
4408  APInt LoadedRHSOffset;
4409  if (!IsConstantOffsetFromGlobal(LoadedRHS, LoadedRHSSym, LoadedRHSOffset,
4410  DL) ||
4411  PtrSym != LoadedRHSSym || PtrOffset != LoadedRHSOffset)
4412  return nullptr;
4413 
4414  return ConstantExpr::getBitCast(LoadedLHSPtr, Int8PtrTy);
4415 }
4416 
4418  auto *ConstMask = dyn_cast<Constant>(Mask);
4419  if (!ConstMask)
4420  return false;
4421  if (ConstMask->isNullValue() || isa<UndefValue>(ConstMask))
4422  return true;
4423  for (unsigned I = 0, E = ConstMask->getType()->getVectorNumElements(); I != E;
4424  ++I) {
4425  if (auto *MaskElt = ConstMask->getAggregateElement(I))
4426  if (MaskElt->isNullValue() || isa<UndefValue>(MaskElt))
4427  continue;
4428  return false;
4429  }
4430  return true;
4431 }
4432 
4433 template <typename IterTy>
4434 static Value *SimplifyIntrinsic(Function *F, IterTy ArgBegin, IterTy ArgEnd,
4435  const SimplifyQuery &Q, unsigned MaxRecurse) {
4436  Intrinsic::ID IID = F->getIntrinsicID();
4437  unsigned NumOperands = std::distance(ArgBegin, ArgEnd);
4438 
4439  // Unary Ops
4440  if (NumOperands == 1) {
4441  // Perform idempotent optimizations
4442  if (IsIdempotent(IID)) {
4443  if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin)) {
4444  if (II->getIntrinsicID() == IID)
4445  return II;
4446  }
4447  }
4448 
4449  switch (IID) {
4450  case Intrinsic::fabs: {
4451  if (SignBitMustBeZero(*ArgBegin, Q.TLI))
4452  return *ArgBegin;
4453  return nullptr;
4454  }
4455  default:
4456  return nullptr;
4457  }
4458  }
4459 
4460  // Binary Ops
4461  if (NumOperands == 2) {
4462  Value *LHS = *ArgBegin;
4463  Value *RHS = *(ArgBegin + 1);
4464  Type *ReturnType = F->getReturnType();
4465 
4466  switch (IID) {
4467  case Intrinsic::usub_with_overflow:
4468  case Intrinsic::ssub_with_overflow: {
4469  // X - X -> { 0, false }
4470  if (LHS == RHS)
4471  return Constant::getNullValue(ReturnType);
4472 
4473  // X - undef -> undef
4474  // undef - X -> undef
4475  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
4476  return UndefValue::get(ReturnType);
4477 
4478  return nullptr;
4479  }
4480  case Intrinsic::uadd_with_overflow:
4481  case Intrinsic::sadd_with_overflow: {
4482  // X + undef -> undef
4483  if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
4484  return UndefValue::get(ReturnType);
4485 
4486  return nullptr;
4487  }
4488  case Intrinsic::umul_with_overflow:
4489  case Intrinsic::smul_with_overflow: {
4490  // 0 * X -> { 0, false }
4491  // X * 0 -> { 0, false }
4492  if (match(LHS, m_Zero()) || match(RHS, m_Zero()))
4493  return Constant::getNullValue(ReturnType);
4494 
4495  // undef * X -> { 0, false }
4496  // X * undef -> { 0, false }
4497  if (match(LHS, m_Undef()) || match(RHS, m_Undef()))
4498  return Constant::getNullValue(ReturnType);
4499 
4500  return nullptr;
4501  }
4502  case Intrinsic::load_relative: {
4503  Constant *C0 = dyn_cast<Constant>(LHS);
4504  Constant *C1 = dyn_cast<Constant>(RHS);
4505  if (C0 && C1)
4506  return SimplifyRelativeLoad(C0, C1, Q.DL);
4507  return nullptr;
4508  }
4509  default:
4510  return nullptr;
4511  }
4512  }
4513 
4514  // Simplify calls to llvm.masked.load.*
4515  switch (IID) {
4516  case Intrinsic::masked_load: {
4517  Value *MaskArg = ArgBegin[2];
4518  Value *PassthruArg = ArgBegin[3];
4519  // If the mask is all zeros or undef, the "passthru" argument is the result.
4520  if (maskIsAllZeroOrUndef(MaskArg))
4521  return PassthruArg;
4522  return nullptr;
4523  }
4524  default:
4525  return nullptr;
4526  }
4527 }
4528 
4529 template <typename IterTy>
4530 static Value *SimplifyCall(ImmutableCallSite CS, Value *V, IterTy ArgBegin,
4531  IterTy ArgEnd, const SimplifyQuery &Q,
4532  unsigned MaxRecurse) {
4533  Type *Ty = V->getType();
4534  if (PointerType *PTy = dyn_cast<PointerType>(Ty))
4535  Ty = PTy->getElementType();
4536  FunctionType *FTy = cast<FunctionType>(Ty);
4537 
4538  // call undef -> undef
4539  // call null -> undef
4540  if (isa<UndefValue>(V) || isa<ConstantPointerNull>(V))
4541  return UndefValue::get(FTy->getReturnType());
4542 
4543  Function *F = dyn_cast<Function>(V);
4544  if (!F)
4545  return nullptr;
4546 
4547  if (F->isIntrinsic())
4548  if (Value *Ret = SimplifyIntrinsic(F, ArgBegin, ArgEnd, Q, MaxRecurse))
4549  return Ret;
4550 
4551  if (!canConstantFoldCallTo(CS, F))
4552  return nullptr;
4553 
4554  SmallVector<Constant *, 4> ConstantArgs;
4555  ConstantArgs.reserve(ArgEnd - ArgBegin);
4556  for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
4557  Constant *C = dyn_cast<Constant>(*I);
4558  if (!C)
4559  return nullptr;
4560  ConstantArgs.push_back(C);
4561  }
4562 
4563  return ConstantFoldCall(CS, F, ConstantArgs, Q.TLI);
4564 }
4565 
4567  User::op_iterator ArgBegin, User::op_iterator ArgEnd,
4568  const SimplifyQuery &Q) {
4569  return ::SimplifyCall(CS, V, ArgBegin, ArgEnd, Q, RecursionLimit);
4570 }
4571 
4573  ArrayRef<Value *> Args, const SimplifyQuery &Q) {
4574  return ::SimplifyCall(CS, V, Args.begin(), Args.end(), Q, RecursionLimit);
4575 }
4576 
4577 /// See if we can compute a simplified version of this instruction.
4578 /// If not, this returns null.
4579 
4582  const SimplifyQuery Q = SQ.CxtI ? SQ : SQ.getWithInstruction(I);
4583  Value *Result;
4584 
4585  switch (I->getOpcode()) {
4586  default:
4587  Result = ConstantFoldInstruction(I, Q.DL, Q.TLI);
4588  break;
4589  case Instruction::FAdd:
4590  Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
4591  I->getFastMathFlags(), Q);
4592  break;
4593  case Instruction::Add:
4594  Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
4595  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4596  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4597  break;
4598  case Instruction::FSub:
4599  Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
4600  I->getFastMathFlags(), Q);
4601  break;
4602  case Instruction::Sub:
4603  Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
4604  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4605  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4606  break;
4607  case Instruction::FMul:
4608  Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
4609  I->getFastMathFlags(), Q);
4610  break;
4611  case Instruction::Mul:
4612  Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), Q);
4613  break;
4614  case Instruction::SDiv:
4615  Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), Q);
4616  break;
4617  case Instruction::UDiv:
4618  Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), Q);
4619  break;
4620  case Instruction::FDiv:
4621  Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1),
4622  I->getFastMathFlags(), Q);
4623  break;
4624  case Instruction::SRem:
4625  Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), Q);
4626  break;
4627  case Instruction::URem:
4628  Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), Q);
4629  break;
4630  case Instruction::FRem:
4631  Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1),
4632  I->getFastMathFlags(), Q);
4633  break;
4634  case Instruction::Shl:
4635  Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
4636  cast<BinaryOperator>(I)->hasNoSignedWrap(),
4637  cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
4638  break;
4639  case Instruction::LShr:
4640  Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
4641  cast<BinaryOperator>(I)->isExact(), Q);
4642  break;
4643  case Instruction::AShr:
4644  Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
4645  cast<BinaryOperator>(I)->isExact(), Q);
4646  break;
4647  case Instruction::And:
4648  Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), Q);
4649  break;
4650  case Instruction::Or:
4651  Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), Q);
4652  break;
4653  case Instruction::Xor:
4654  Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), Q);
4655  break;
4656  case Instruction::ICmp:
4657  Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
4658  I->getOperand(0), I->getOperand(1), Q);
4659  break;
4660  case Instruction::FCmp:
4661  Result =
4662  SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(), I->getOperand(0),
4663  I->getOperand(1), I->getFastMathFlags(), Q);
4664  break;
4665  case Instruction::Select:
4666  Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
4667  I->getOperand(2), Q);
4668  break;
4669  case Instruction::GetElementPtr: {
4670  SmallVector<Value *, 8> Ops(I->op_begin(), I->op_end());
4671  Result = SimplifyGEPInst(cast<GetElementPtrInst>(I)->getSourceElementType(),
4672  Ops, Q);
4673  break;
4674  }
4675  case Instruction::InsertValue: {
4676  InsertValueInst *IV = cast<InsertValueInst>(I);
4679  IV->getIndices(), Q);
4680  break;
4681  }
4682  case Instruction::ExtractValue: {
4683  auto *EVI = cast<ExtractValueInst>(I);
4684  Result = SimplifyExtractValueInst(EVI->getAggregateOperand(),
4685  EVI->getIndices(), Q);
4686  break;
4687  }
4688  case Instruction::ExtractElement: {
4689  auto *EEI = cast<ExtractElementInst>(I);
4690  Result = SimplifyExtractElementInst(EEI->getVectorOperand(),
4691  EEI->getIndexOperand(), Q);
4692  break;
4693  }
4694  case Instruction::ShuffleVector: {
4695  auto *SVI = cast<ShuffleVectorInst>(I);
4696  Result = SimplifyShuffleVectorInst(SVI->getOperand(0), SVI->getOperand(1),
4697  SVI->getMask(), SVI->getType(), Q);
4698  break;
4699  }
4700  case Instruction::PHI:
4701  Result = SimplifyPHINode(cast<PHINode>(I), Q);
4702  break;
4703  case Instruction::Call: {
4704  CallSite CS(cast<CallInst>(I));
4705  Result = SimplifyCall(CS, CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
4706  Q);
4707  break;
4708  }
4709 #define HANDLE_CAST_INST(num, opc, clas) case Instruction::opc:
4710 #include "llvm/IR/Instruction.def"
4711 #undef HANDLE_CAST_INST
4712  Result =
4713  SimplifyCastInst(I->getOpcode(), I->getOperand(0), I->getType(), Q);
4714  break;
4715  case Instruction::Alloca:
4716  // No simplifications for Alloca and it can't be constant folded.
4717  Result = nullptr;
4718  break;
4719  }
4720 
4721  // In general, it is possible for computeKnownBits to determine all bits in a
4722  // value even when the operands are not all constants.
4723  if (!Result && I->getType()->isIntOrIntVectorTy()) {
4724  KnownBits Known = computeKnownBits(I, Q.DL, /*Depth*/ 0, Q.AC, I, Q.DT, ORE);
4725  if (Known.isConstant())
4726  Result = ConstantInt::get(I->getType(), Known.getConstant());
4727  }
4728 
4729  /// If called on unreachable code, the above logic may report that the
4730  /// instruction simplified to itself. Make life easier for users by
4731  /// detecting that case here, returning a safe value instead.
4732  return Result == I ? UndefValue::get(I->getType()) : Result;
4733 }
4734 
4735 /// \brief Implementation of recursive simplification through an instruction's
4736 /// uses.
4737 ///
4738 /// This is the common implementation of the recursive simplification routines.
4739 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
4740 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
4741 /// instructions to process and attempt to simplify it using
4742 /// InstructionSimplify.
4743 ///
4744 /// This routine returns 'true' only when *it* simplifies something. The passed
4745 /// in simplified value does not count toward this.
4747  const TargetLibraryInfo *TLI,
4748  const DominatorTree *DT,
4749  AssumptionCache *AC) {
4750  bool Simplified = false;
4752  const DataLayout &DL = I->getModule()->getDataLayout();
4753 
4754  // If we have an explicit value to collapse to, do that round of the
4755  // simplification loop by hand initially.
4756  if (SimpleV) {
4757  for (User *U : I->users())
4758  if (U != I)
4759  Worklist.insert(cast<Instruction>(U));
4760 
4761  // Replace the instruction with its simplified value.
4762  I->replaceAllUsesWith(SimpleV);
4763 
4764  // Gracefully handle edge cases where the instruction is not wired into any
4765  // parent block.
4766  if (I->getParent() && !I->isEHPad() && !isa<TerminatorInst>(I) &&
4767  !I->mayHaveSideEffects())
4768  I->eraseFromParent();
4769  } else {
4770  Worklist.insert(I);
4771  }
4772 
4773  // Note that we must test the size on each iteration, the worklist can grow.
4774  for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
4775  I = Worklist[Idx];
4776 
4777  // See if this instruction simplifies.
4778  SimpleV = SimplifyInstruction(I, {DL, TLI, DT, AC});
4779  if (!SimpleV)
4780  continue;
4781 
4782  Simplified = true;
4783 
4784  // Stash away all the uses of the old instruction so we can check them for
4785  // recursive simplifications after a RAUW. This is cheaper than checking all
4786  // uses of To on the recursive step in most cases.
4787  for (User *U : I->users())
4788  Worklist.insert(cast<Instruction>(U));
4789 
4790  // Replace the instruction with its simplified value.
4791  I->replaceAllUsesWith(SimpleV);
4792 
4793  // Gracefully handle edge cases where the instruction is not wired into any
4794  // parent block.
4795  if (I->getParent() && !I->isEHPad() && !isa<TerminatorInst>(I) &&
4796  !I->mayHaveSideEffects())
4797  I->eraseFromParent();
4798  }
4799  return Simplified;
4800 }
4801 
4803  const TargetLibraryInfo *TLI,
4804  const DominatorTree *DT,
4805  AssumptionCache *AC) {
4806  return replaceAndRecursivelySimplifyImpl(I, nullptr, TLI, DT, AC);
4807 }
4808 
4810  const TargetLibraryInfo *TLI,
4811  const DominatorTree *DT,
4812  AssumptionCache *AC) {
4813  assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
4814  assert(SimpleV && "Must provide a simplified value.");
4815  return replaceAndRecursivelySimplifyImpl(I, SimpleV, TLI, DT, AC);
4816 }
4817 
4818 namespace llvm {
4821  auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
4823  auto *TLI = TLIWP ? &TLIWP->getTLI() : nullptr;
4825  auto *AC = ACWP ? &ACWP->getAssumptionCache(F) : nullptr;
4826  return {F.getParent()->getDataLayout(), TLI, DT, AC};
4827 }
4828 
4830  const DataLayout &DL) {
4831  return {DL, &AR.TLI, &AR.DT, &AR.AC};
4832 }
4833 
4834 template <class T, class... TArgs>
4836  Function &F) {
4837  auto *DT = AM.template getCachedResult<DominatorTreeAnalysis>(F);
4838  auto *TLI = AM.template getCachedResult<TargetLibraryAnalysis>(F);
4839  auto *AC = AM.template getCachedResult<AssumptionAnalysis>(F);
4840  return {F.getParent()->getDataLayout(), TLI, DT, AC};
4841 }
4843  Function &);
4844 }
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:944
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:843
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
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