LLVM  8.0.0svn
InstCombineSelect.cpp
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1 //===- InstCombineSelect.cpp ----------------------------------------------===//
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 the visitSelect function.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "InstCombineInternal.h"
15 #include "llvm/ADT/APInt.h"
16 #include "llvm/ADT/Optional.h"
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/ADT/SmallVector.h"
23 #include "llvm/IR/BasicBlock.h"
24 #include "llvm/IR/Constant.h"
25 #include "llvm/IR/Constants.h"
26 #include "llvm/IR/DerivedTypes.h"
27 #include "llvm/IR/IRBuilder.h"
28 #include "llvm/IR/InstrTypes.h"
29 #include "llvm/IR/Instruction.h"
30 #include "llvm/IR/Instructions.h"
31 #include "llvm/IR/IntrinsicInst.h"
32 #include "llvm/IR/Intrinsics.h"
33 #include "llvm/IR/Operator.h"
34 #include "llvm/IR/PatternMatch.h"
35 #include "llvm/IR/Type.h"
36 #include "llvm/IR/User.h"
37 #include "llvm/IR/Value.h"
38 #include "llvm/Support/Casting.h"
40 #include "llvm/Support/KnownBits.h"
42 #include <cassert>
43 #include <utility>
44 
45 using namespace llvm;
46 using namespace PatternMatch;
47 
48 #define DEBUG_TYPE "instcombine"
49 
51  SelectPatternFlavor SPF, Value *A, Value *B) {
53  assert(CmpInst::isIntPredicate(Pred) && "Expected integer predicate");
54  return Builder.CreateSelect(Builder.CreateICmp(Pred, A, B), A, B);
55 }
56 
57 /// Replace a select operand based on an equality comparison with the identity
58 /// constant of a binop.
60  const TargetLibraryInfo &TLI) {
61  // The select condition must be an equality compare with a constant operand.
62  Value *X;
63  Constant *C;
64  CmpInst::Predicate Pred;
65  if (!match(Sel.getCondition(), m_Cmp(Pred, m_Value(X), m_Constant(C))))
66  return nullptr;
67 
68  bool IsEq;
69  if (ICmpInst::isEquality(Pred))
70  IsEq = Pred == ICmpInst::ICMP_EQ;
71  else if (Pred == FCmpInst::FCMP_OEQ)
72  IsEq = true;
73  else if (Pred == FCmpInst::FCMP_UNE)
74  IsEq = false;
75  else
76  return nullptr;
77 
78  // A select operand must be a binop, and the compare constant must be the
79  // identity constant for that binop.
80  BinaryOperator *BO;
81  if (!match(Sel.getOperand(IsEq ? 1 : 2), m_BinOp(BO)) ||
82  ConstantExpr::getBinOpIdentity(BO->getOpcode(), BO->getType(), true) != C)
83  return nullptr;
84 
85  // Last, match the compare variable operand with a binop operand.
86  Value *Y;
87  if (!BO->isCommutative() && !match(BO, m_BinOp(m_Value(Y), m_Specific(X))))
88  return nullptr;
89  if (!match(BO, m_c_BinOp(m_Value(Y), m_Specific(X))))
90  return nullptr;
91 
92  // +0.0 compares equal to -0.0, and so it does not behave as required for this
93  // transform. Bail out if we can not exclude that possibility.
94  if (isa<FPMathOperator>(BO))
95  if (!BO->hasNoSignedZeros() && !CannotBeNegativeZero(Y, &TLI))
96  return nullptr;
97 
98  // BO = binop Y, X
99  // S = { select (cmp eq X, C), BO, ? } or { select (cmp ne X, C), ?, BO }
100  // =>
101  // S = { select (cmp eq X, C), Y, ? } or { select (cmp ne X, C), ?, Y }
102  Sel.setOperand(IsEq ? 1 : 2, Y);
103  return &Sel;
104 }
105 
106 /// This folds:
107 /// select (icmp eq (and X, C1)), TC, FC
108 /// iff C1 is a power 2 and the difference between TC and FC is a power-of-2.
109 /// To something like:
110 /// (shr (and (X, C1)), (log2(C1) - log2(TC-FC))) + FC
111 /// Or:
112 /// (shl (and (X, C1)), (log2(TC-FC) - log2(C1))) + FC
113 /// With some variations depending if FC is larger than TC, or the shift
114 /// isn't needed, or the bit widths don't match.
116  InstCombiner::BuilderTy &Builder) {
117  const APInt *SelTC, *SelFC;
118  if (!match(Sel.getTrueValue(), m_APInt(SelTC)) ||
119  !match(Sel.getFalseValue(), m_APInt(SelFC)))
120  return nullptr;
121 
122  // If this is a vector select, we need a vector compare.
123  Type *SelType = Sel.getType();
124  if (SelType->isVectorTy() != Cmp->getType()->isVectorTy())
125  return nullptr;
126 
127  Value *V;
128  APInt AndMask;
129  bool CreateAnd = false;
130  ICmpInst::Predicate Pred = Cmp->getPredicate();
131  if (ICmpInst::isEquality(Pred)) {
132  if (!match(Cmp->getOperand(1), m_Zero()))
133  return nullptr;
134 
135  V = Cmp->getOperand(0);
136  const APInt *AndRHS;
137  if (!match(V, m_And(m_Value(), m_Power2(AndRHS))))
138  return nullptr;
139 
140  AndMask = *AndRHS;
141  } else if (decomposeBitTestICmp(Cmp->getOperand(0), Cmp->getOperand(1),
142  Pred, V, AndMask)) {
143  assert(ICmpInst::isEquality(Pred) && "Not equality test?");
144  if (!AndMask.isPowerOf2())
145  return nullptr;
146 
147  CreateAnd = true;
148  } else {
149  return nullptr;
150  }
151 
152  // In general, when both constants are non-zero, we would need an offset to
153  // replace the select. This would require more instructions than we started
154  // with. But there's one special-case that we handle here because it can
155  // simplify/reduce the instructions.
156  APInt TC = *SelTC;
157  APInt FC = *SelFC;
158  if (!TC.isNullValue() && !FC.isNullValue()) {
159  // If the select constants differ by exactly one bit and that's the same
160  // bit that is masked and checked by the select condition, the select can
161  // be replaced by bitwise logic to set/clear one bit of the constant result.
162  if (TC.getBitWidth() != AndMask.getBitWidth() || (TC ^ FC) != AndMask)
163  return nullptr;
164  if (CreateAnd) {
165  // If we have to create an 'and', then we must kill the cmp to not
166  // increase the instruction count.
167  if (!Cmp->hasOneUse())
168  return nullptr;
169  V = Builder.CreateAnd(V, ConstantInt::get(SelType, AndMask));
170  }
171  bool ExtraBitInTC = TC.ugt(FC);
172  if (Pred == ICmpInst::ICMP_EQ) {
173  // If the masked bit in V is clear, clear or set the bit in the result:
174  // (V & AndMaskC) == 0 ? TC : FC --> (V & AndMaskC) ^ TC
175  // (V & AndMaskC) == 0 ? TC : FC --> (V & AndMaskC) | TC
176  Constant *C = ConstantInt::get(SelType, TC);
177  return ExtraBitInTC ? Builder.CreateXor(V, C) : Builder.CreateOr(V, C);
178  }
179  if (Pred == ICmpInst::ICMP_NE) {
180  // If the masked bit in V is set, set or clear the bit in the result:
181  // (V & AndMaskC) != 0 ? TC : FC --> (V & AndMaskC) | FC
182  // (V & AndMaskC) != 0 ? TC : FC --> (V & AndMaskC) ^ FC
183  Constant *C = ConstantInt::get(SelType, FC);
184  return ExtraBitInTC ? Builder.CreateOr(V, C) : Builder.CreateXor(V, C);
185  }
186  llvm_unreachable("Only expecting equality predicates");
187  }
188 
189  // Make sure one of the select arms is a power-of-2.
190  if (!TC.isPowerOf2() && !FC.isPowerOf2())
191  return nullptr;
192 
193  // Determine which shift is needed to transform result of the 'and' into the
194  // desired result.
195  const APInt &ValC = !TC.isNullValue() ? TC : FC;
196  unsigned ValZeros = ValC.logBase2();
197  unsigned AndZeros = AndMask.logBase2();
198 
199  // Insert the 'and' instruction on the input to the truncate.
200  if (CreateAnd)
201  V = Builder.CreateAnd(V, ConstantInt::get(V->getType(), AndMask));
202 
203  // If types don't match, we can still convert the select by introducing a zext
204  // or a trunc of the 'and'.
205  if (ValZeros > AndZeros) {
206  V = Builder.CreateZExtOrTrunc(V, SelType);
207  V = Builder.CreateShl(V, ValZeros - AndZeros);
208  } else if (ValZeros < AndZeros) {
209  V = Builder.CreateLShr(V, AndZeros - ValZeros);
210  V = Builder.CreateZExtOrTrunc(V, SelType);
211  } else {
212  V = Builder.CreateZExtOrTrunc(V, SelType);
213  }
214 
215  // Okay, now we know that everything is set up, we just don't know whether we
216  // have a icmp_ne or icmp_eq and whether the true or false val is the zero.
217  bool ShouldNotVal = !TC.isNullValue();
218  ShouldNotVal ^= Pred == ICmpInst::ICMP_NE;
219  if (ShouldNotVal)
220  V = Builder.CreateXor(V, ValC);
221 
222  return V;
223 }
224 
225 /// We want to turn code that looks like this:
226 /// %C = or %A, %B
227 /// %D = select %cond, %C, %A
228 /// into:
229 /// %C = select %cond, %B, 0
230 /// %D = or %A, %C
231 ///
232 /// Assuming that the specified instruction is an operand to the select, return
233 /// a bitmask indicating which operands of this instruction are foldable if they
234 /// equal the other incoming value of the select.
236  switch (I->getOpcode()) {
237  case Instruction::Add:
238  case Instruction::Mul:
239  case Instruction::And:
240  case Instruction::Or:
241  case Instruction::Xor:
242  return 3; // Can fold through either operand.
243  case Instruction::Sub: // Can only fold on the amount subtracted.
244  case Instruction::Shl: // Can only fold on the shift amount.
245  case Instruction::LShr:
246  case Instruction::AShr:
247  return 1;
248  default:
249  return 0; // Cannot fold
250  }
251 }
252 
253 /// For the same transformation as the previous function, return the identity
254 /// constant that goes into the select.
256  switch (I->getOpcode()) {
257  default: llvm_unreachable("This cannot happen!");
258  case Instruction::Add:
259  case Instruction::Sub:
260  case Instruction::Or:
261  case Instruction::Xor:
262  case Instruction::Shl:
263  case Instruction::LShr:
264  case Instruction::AShr:
266  case Instruction::And:
268  case Instruction::Mul:
269  return APInt(I->getType()->getScalarSizeInBits(), 1);
270  }
271 }
272 
273 /// We have (select c, TI, FI), and we know that TI and FI have the same opcode.
274 Instruction *InstCombiner::foldSelectOpOp(SelectInst &SI, Instruction *TI,
275  Instruction *FI) {
276  // Don't break up min/max patterns. The hasOneUse checks below prevent that
277  // for most cases, but vector min/max with bitcasts can be transformed. If the
278  // one-use restrictions are eased for other patterns, we still don't want to
279  // obfuscate min/max.
280  if ((match(&SI, m_SMin(m_Value(), m_Value())) ||
281  match(&SI, m_SMax(m_Value(), m_Value())) ||
282  match(&SI, m_UMin(m_Value(), m_Value())) ||
283  match(&SI, m_UMax(m_Value(), m_Value()))))
284  return nullptr;
285 
286  // If this is a cast from the same type, merge.
287  if (TI->getNumOperands() == 1 && TI->isCast()) {
288  Type *FIOpndTy = FI->getOperand(0)->getType();
289  if (TI->getOperand(0)->getType() != FIOpndTy)
290  return nullptr;
291 
292  // The select condition may be a vector. We may only change the operand
293  // type if the vector width remains the same (and matches the condition).
294  Type *CondTy = SI.getCondition()->getType();
295  if (CondTy->isVectorTy()) {
296  if (!FIOpndTy->isVectorTy())
297  return nullptr;
298  if (CondTy->getVectorNumElements() != FIOpndTy->getVectorNumElements())
299  return nullptr;
300 
301  // TODO: If the backend knew how to deal with casts better, we could
302  // remove this limitation. For now, there's too much potential to create
303  // worse codegen by promoting the select ahead of size-altering casts
304  // (PR28160).
305  //
306  // Note that ValueTracking's matchSelectPattern() looks through casts
307  // without checking 'hasOneUse' when it matches min/max patterns, so this
308  // transform may end up happening anyway.
309  if (TI->getOpcode() != Instruction::BitCast &&
310  (!TI->hasOneUse() || !FI->hasOneUse()))
311  return nullptr;
312  } else if (!TI->hasOneUse() || !FI->hasOneUse()) {
313  // TODO: The one-use restrictions for a scalar select could be eased if
314  // the fold of a select in visitLoadInst() was enhanced to match a pattern
315  // that includes a cast.
316  return nullptr;
317  }
318 
319  // Fold this by inserting a select from the input values.
320  Value *NewSI =
321  Builder.CreateSelect(SI.getCondition(), TI->getOperand(0),
322  FI->getOperand(0), SI.getName() + ".v", &SI);
323  return CastInst::Create(Instruction::CastOps(TI->getOpcode()), NewSI,
324  TI->getType());
325  }
326 
327  // Only handle binary operators (including two-operand getelementptr) with
328  // one-use here. As with the cast case above, it may be possible to relax the
329  // one-use constraint, but that needs be examined carefully since it may not
330  // reduce the total number of instructions.
331  if (TI->getNumOperands() != 2 || FI->getNumOperands() != 2 ||
332  (!isa<BinaryOperator>(TI) && !isa<GetElementPtrInst>(TI)) ||
333  !TI->hasOneUse() || !FI->hasOneUse())
334  return nullptr;
335 
336  // Figure out if the operations have any operands in common.
337  Value *MatchOp, *OtherOpT, *OtherOpF;
338  bool MatchIsOpZero;
339  if (TI->getOperand(0) == FI->getOperand(0)) {
340  MatchOp = TI->getOperand(0);
341  OtherOpT = TI->getOperand(1);
342  OtherOpF = FI->getOperand(1);
343  MatchIsOpZero = true;
344  } else if (TI->getOperand(1) == FI->getOperand(1)) {
345  MatchOp = TI->getOperand(1);
346  OtherOpT = TI->getOperand(0);
347  OtherOpF = FI->getOperand(0);
348  MatchIsOpZero = false;
349  } else if (!TI->isCommutative()) {
350  return nullptr;
351  } else if (TI->getOperand(0) == FI->getOperand(1)) {
352  MatchOp = TI->getOperand(0);
353  OtherOpT = TI->getOperand(1);
354  OtherOpF = FI->getOperand(0);
355  MatchIsOpZero = true;
356  } else if (TI->getOperand(1) == FI->getOperand(0)) {
357  MatchOp = TI->getOperand(1);
358  OtherOpT = TI->getOperand(0);
359  OtherOpF = FI->getOperand(1);
360  MatchIsOpZero = true;
361  } else {
362  return nullptr;
363  }
364 
365  // If the select condition is a vector, the operands of the original select's
366  // operands also must be vectors. This may not be the case for getelementptr
367  // for example.
368  if (SI.getCondition()->getType()->isVectorTy() &&
369  (!OtherOpT->getType()->isVectorTy() ||
370  !OtherOpF->getType()->isVectorTy()))
371  return nullptr;
372 
373  // If we reach here, they do have operations in common.
374  Value *NewSI = Builder.CreateSelect(SI.getCondition(), OtherOpT, OtherOpF,
375  SI.getName() + ".v", &SI);
376  Value *Op0 = MatchIsOpZero ? MatchOp : NewSI;
377  Value *Op1 = MatchIsOpZero ? NewSI : MatchOp;
378  if (auto *BO = dyn_cast<BinaryOperator>(TI)) {
379  BinaryOperator *NewBO = BinaryOperator::Create(BO->getOpcode(), Op0, Op1);
380  NewBO->copyIRFlags(TI);
381  NewBO->andIRFlags(FI);
382  return NewBO;
383  }
384  if (auto *TGEP = dyn_cast<GetElementPtrInst>(TI)) {
385  auto *FGEP = cast<GetElementPtrInst>(FI);
386  Type *ElementType = TGEP->getResultElementType();
387  return TGEP->isInBounds() && FGEP->isInBounds()
388  ? GetElementPtrInst::CreateInBounds(ElementType, Op0, {Op1})
389  : GetElementPtrInst::Create(ElementType, Op0, {Op1});
390  }
391  llvm_unreachable("Expected BinaryOperator or GEP");
392  return nullptr;
393 }
394 
395 static bool isSelect01(const APInt &C1I, const APInt &C2I) {
396  if (!C1I.isNullValue() && !C2I.isNullValue()) // One side must be zero.
397  return false;
398  return C1I.isOneValue() || C1I.isAllOnesValue() ||
399  C2I.isOneValue() || C2I.isAllOnesValue();
400 }
401 
402 /// Try to fold the select into one of the operands to allow further
403 /// optimization.
404 Instruction *InstCombiner::foldSelectIntoOp(SelectInst &SI, Value *TrueVal,
405  Value *FalseVal) {
406  // See the comment above GetSelectFoldableOperands for a description of the
407  // transformation we are doing here.
408  if (auto *TVI = dyn_cast<BinaryOperator>(TrueVal)) {
409  if (TVI->hasOneUse() && !isa<Constant>(FalseVal)) {
410  if (unsigned SFO = getSelectFoldableOperands(TVI)) {
411  unsigned OpToFold = 0;
412  if ((SFO & 1) && FalseVal == TVI->getOperand(0)) {
413  OpToFold = 1;
414  } else if ((SFO & 2) && FalseVal == TVI->getOperand(1)) {
415  OpToFold = 2;
416  }
417 
418  if (OpToFold) {
420  Value *OOp = TVI->getOperand(2-OpToFold);
421  // Avoid creating select between 2 constants unless it's selecting
422  // between 0, 1 and -1.
423  const APInt *OOpC;
424  bool OOpIsAPInt = match(OOp, m_APInt(OOpC));
425  if (!isa<Constant>(OOp) || (OOpIsAPInt && isSelect01(CI, *OOpC))) {
426  Value *C = ConstantInt::get(OOp->getType(), CI);
427  Value *NewSel = Builder.CreateSelect(SI.getCondition(), OOp, C);
428  NewSel->takeName(TVI);
429  BinaryOperator *BO = BinaryOperator::Create(TVI->getOpcode(),
430  FalseVal, NewSel);
431  BO->copyIRFlags(TVI);
432  return BO;
433  }
434  }
435  }
436  }
437  }
438 
439  if (auto *FVI = dyn_cast<BinaryOperator>(FalseVal)) {
440  if (FVI->hasOneUse() && !isa<Constant>(TrueVal)) {
441  if (unsigned SFO = getSelectFoldableOperands(FVI)) {
442  unsigned OpToFold = 0;
443  if ((SFO & 1) && TrueVal == FVI->getOperand(0)) {
444  OpToFold = 1;
445  } else if ((SFO & 2) && TrueVal == FVI->getOperand(1)) {
446  OpToFold = 2;
447  }
448 
449  if (OpToFold) {
451  Value *OOp = FVI->getOperand(2-OpToFold);
452  // Avoid creating select between 2 constants unless it's selecting
453  // between 0, 1 and -1.
454  const APInt *OOpC;
455  bool OOpIsAPInt = match(OOp, m_APInt(OOpC));
456  if (!isa<Constant>(OOp) || (OOpIsAPInt && isSelect01(CI, *OOpC))) {
457  Value *C = ConstantInt::get(OOp->getType(), CI);
458  Value *NewSel = Builder.CreateSelect(SI.getCondition(), C, OOp);
459  NewSel->takeName(FVI);
460  BinaryOperator *BO = BinaryOperator::Create(FVI->getOpcode(),
461  TrueVal, NewSel);
462  BO->copyIRFlags(FVI);
463  return BO;
464  }
465  }
466  }
467  }
468  }
469 
470  return nullptr;
471 }
472 
473 /// We want to turn:
474 /// (select (icmp eq (and X, Y), 0), (and (lshr X, Z), 1), 1)
475 /// into:
476 /// zext (icmp ne i32 (and X, (or Y, (shl 1, Z))), 0)
477 /// Note:
478 /// Z may be 0 if lshr is missing.
479 /// Worst-case scenario is that we will replace 5 instructions with 5 different
480 /// instructions, but we got rid of select.
481 static Instruction *foldSelectICmpAndAnd(Type *SelType, const ICmpInst *Cmp,
482  Value *TVal, Value *FVal,
483  InstCombiner::BuilderTy &Builder) {
484  if (!(Cmp->hasOneUse() && Cmp->getOperand(0)->hasOneUse() &&
485  Cmp->getPredicate() == ICmpInst::ICMP_EQ &&
486  match(Cmp->getOperand(1), m_Zero()) && match(FVal, m_One())))
487  return nullptr;
488 
489  // The TrueVal has general form of: and %B, 1
490  Value *B;
491  if (!match(TVal, m_OneUse(m_And(m_Value(B), m_One()))))
492  return nullptr;
493 
494  // Where %B may be optionally shifted: lshr %X, %Z.
495  Value *X, *Z;
496  const bool HasShift = match(B, m_OneUse(m_LShr(m_Value(X), m_Value(Z))));
497  if (!HasShift)
498  X = B;
499 
500  Value *Y;
501  if (!match(Cmp->getOperand(0), m_c_And(m_Specific(X), m_Value(Y))))
502  return nullptr;
503 
504  // ((X & Y) == 0) ? ((X >> Z) & 1) : 1 --> (X & (Y | (1 << Z))) != 0
505  // ((X & Y) == 0) ? (X & 1) : 1 --> (X & (Y | 1)) != 0
506  Constant *One = ConstantInt::get(SelType, 1);
507  Value *MaskB = HasShift ? Builder.CreateShl(One, Z) : One;
508  Value *FullMask = Builder.CreateOr(Y, MaskB);
509  Value *MaskedX = Builder.CreateAnd(X, FullMask);
510  Value *ICmpNeZero = Builder.CreateIsNotNull(MaskedX);
511  return new ZExtInst(ICmpNeZero, SelType);
512 }
513 
514 /// We want to turn:
515 /// (select (icmp eq (and X, C1), 0), Y, (or Y, C2))
516 /// into:
517 /// (or (shl (and X, C1), C3), Y)
518 /// iff:
519 /// C1 and C2 are both powers of 2
520 /// where:
521 /// C3 = Log(C2) - Log(C1)
522 ///
523 /// This transform handles cases where:
524 /// 1. The icmp predicate is inverted
525 /// 2. The select operands are reversed
526 /// 3. The magnitude of C2 and C1 are flipped
527 static Value *foldSelectICmpAndOr(const ICmpInst *IC, Value *TrueVal,
528  Value *FalseVal,
529  InstCombiner::BuilderTy &Builder) {
530  // Only handle integer compares. Also, if this is a vector select, we need a
531  // vector compare.
532  if (!TrueVal->getType()->isIntOrIntVectorTy() ||
533  TrueVal->getType()->isVectorTy() != IC->getType()->isVectorTy())
534  return nullptr;
535 
536  Value *CmpLHS = IC->getOperand(0);
537  Value *CmpRHS = IC->getOperand(1);
538 
539  Value *V;
540  unsigned C1Log;
541  bool IsEqualZero;
542  bool NeedAnd = false;
543  if (IC->isEquality()) {
544  if (!match(CmpRHS, m_Zero()))
545  return nullptr;
546 
547  const APInt *C1;
548  if (!match(CmpLHS, m_And(m_Value(), m_Power2(C1))))
549  return nullptr;
550 
551  V = CmpLHS;
552  C1Log = C1->logBase2();
553  IsEqualZero = IC->getPredicate() == ICmpInst::ICMP_EQ;
554  } else if (IC->getPredicate() == ICmpInst::ICMP_SLT ||
555  IC->getPredicate() == ICmpInst::ICMP_SGT) {
556  // We also need to recognize (icmp slt (trunc (X)), 0) and
557  // (icmp sgt (trunc (X)), -1).
558  IsEqualZero = IC->getPredicate() == ICmpInst::ICMP_SGT;
559  if ((IsEqualZero && !match(CmpRHS, m_AllOnes())) ||
560  (!IsEqualZero && !match(CmpRHS, m_Zero())))
561  return nullptr;
562 
563  if (!match(CmpLHS, m_OneUse(m_Trunc(m_Value(V)))))
564  return nullptr;
565 
566  C1Log = CmpLHS->getType()->getScalarSizeInBits() - 1;
567  NeedAnd = true;
568  } else {
569  return nullptr;
570  }
571 
572  const APInt *C2;
573  bool OrOnTrueVal = false;
574  bool OrOnFalseVal = match(FalseVal, m_Or(m_Specific(TrueVal), m_Power2(C2)));
575  if (!OrOnFalseVal)
576  OrOnTrueVal = match(TrueVal, m_Or(m_Specific(FalseVal), m_Power2(C2)));
577 
578  if (!OrOnFalseVal && !OrOnTrueVal)
579  return nullptr;
580 
581  Value *Y = OrOnFalseVal ? TrueVal : FalseVal;
582 
583  unsigned C2Log = C2->logBase2();
584 
585  bool NeedXor = (!IsEqualZero && OrOnFalseVal) || (IsEqualZero && OrOnTrueVal);
586  bool NeedShift = C1Log != C2Log;
587  bool NeedZExtTrunc = Y->getType()->getScalarSizeInBits() !=
589 
590  // Make sure we don't create more instructions than we save.
591  Value *Or = OrOnFalseVal ? FalseVal : TrueVal;
592  if ((NeedShift + NeedXor + NeedZExtTrunc) >
593  (IC->hasOneUse() + Or->hasOneUse()))
594  return nullptr;
595 
596  if (NeedAnd) {
597  // Insert the AND instruction on the input to the truncate.
599  V = Builder.CreateAnd(V, ConstantInt::get(V->getType(), C1));
600  }
601 
602  if (C2Log > C1Log) {
603  V = Builder.CreateZExtOrTrunc(V, Y->getType());
604  V = Builder.CreateShl(V, C2Log - C1Log);
605  } else if (C1Log > C2Log) {
606  V = Builder.CreateLShr(V, C1Log - C2Log);
607  V = Builder.CreateZExtOrTrunc(V, Y->getType());
608  } else
609  V = Builder.CreateZExtOrTrunc(V, Y->getType());
610 
611  if (NeedXor)
612  V = Builder.CreateXor(V, *C2);
613 
614  return Builder.CreateOr(V, Y);
615 }
616 
617 /// Transform patterns such as: (a > b) ? a - b : 0
618 /// into: ((a > b) ? a : b) - b)
619 /// This produces a canonical max pattern that is more easily recognized by the
620 /// backend and converted into saturated subtraction instructions if those
621 /// exist.
622 /// There are 8 commuted/swapped variants of this pattern.
623 /// TODO: Also support a - UMIN(a,b) patterns.
625  const Value *TrueVal,
626  const Value *FalseVal,
627  InstCombiner::BuilderTy &Builder) {
628  ICmpInst::Predicate Pred = ICI->getPredicate();
629  if (!ICmpInst::isUnsigned(Pred))
630  return nullptr;
631 
632  // (b > a) ? 0 : a - b -> (b <= a) ? a - b : 0
633  if (match(TrueVal, m_Zero())) {
634  Pred = ICmpInst::getInversePredicate(Pred);
635  std::swap(TrueVal, FalseVal);
636  }
637  if (!match(FalseVal, m_Zero()))
638  return nullptr;
639 
640  Value *A = ICI->getOperand(0);
641  Value *B = ICI->getOperand(1);
642  if (Pred == ICmpInst::ICMP_ULE || Pred == ICmpInst::ICMP_ULT) {
643  // (b < a) ? a - b : 0 -> (a > b) ? a - b : 0
644  std::swap(A, B);
645  Pred = ICmpInst::getSwappedPredicate(Pred);
646  }
647 
648  assert((Pred == ICmpInst::ICMP_UGE || Pred == ICmpInst::ICMP_UGT) &&
649  "Unexpected isUnsigned predicate!");
650 
651  // Account for swapped form of subtraction: ((a > b) ? b - a : 0).
652  bool IsNegative = false;
653  if (match(TrueVal, m_Sub(m_Specific(B), m_Specific(A))))
654  IsNegative = true;
655  else if (!match(TrueVal, m_Sub(m_Specific(A), m_Specific(B))))
656  return nullptr;
657 
658  // If sub is used anywhere else, we wouldn't be able to eliminate it
659  // afterwards.
660  if (!TrueVal->hasOneUse())
661  return nullptr;
662 
663  // All checks passed, convert to canonical unsigned saturated subtraction
664  // form: sub(max()).
665  // (a > b) ? a - b : 0 -> ((a > b) ? a : b) - b)
666  Value *Max = Builder.CreateSelect(Builder.CreateICmp(Pred, A, B), A, B);
667  return IsNegative ? Builder.CreateSub(B, Max) : Builder.CreateSub(Max, B);
668 }
669 
670 /// Attempt to fold a cttz/ctlz followed by a icmp plus select into a single
671 /// call to cttz/ctlz with flag 'is_zero_undef' cleared.
672 ///
673 /// For example, we can fold the following code sequence:
674 /// \code
675 /// %0 = tail call i32 @llvm.cttz.i32(i32 %x, i1 true)
676 /// %1 = icmp ne i32 %x, 0
677 /// %2 = select i1 %1, i32 %0, i32 32
678 /// \code
679 ///
680 /// into:
681 /// %0 = tail call i32 @llvm.cttz.i32(i32 %x, i1 false)
682 static Value *foldSelectCttzCtlz(ICmpInst *ICI, Value *TrueVal, Value *FalseVal,
683  InstCombiner::BuilderTy &Builder) {
684  ICmpInst::Predicate Pred = ICI->getPredicate();
685  Value *CmpLHS = ICI->getOperand(0);
686  Value *CmpRHS = ICI->getOperand(1);
687 
688  // Check if the condition value compares a value for equality against zero.
689  if (!ICI->isEquality() || !match(CmpRHS, m_Zero()))
690  return nullptr;
691 
692  Value *Count = FalseVal;
693  Value *ValueOnZero = TrueVal;
694  if (Pred == ICmpInst::ICMP_NE)
695  std::swap(Count, ValueOnZero);
696 
697  // Skip zero extend/truncate.
698  Value *V = nullptr;
699  if (match(Count, m_ZExt(m_Value(V))) ||
700  match(Count, m_Trunc(m_Value(V))))
701  Count = V;
702 
703  // Check if the value propagated on zero is a constant number equal to the
704  // sizeof in bits of 'Count'.
705  unsigned SizeOfInBits = Count->getType()->getScalarSizeInBits();
706  if (!match(ValueOnZero, m_SpecificInt(SizeOfInBits)))
707  return nullptr;
708 
709  // Check that 'Count' is a call to intrinsic cttz/ctlz. Also check that the
710  // input to the cttz/ctlz is used as LHS for the compare instruction.
711  if (match(Count, m_Intrinsic<Intrinsic::cttz>(m_Specific(CmpLHS))) ||
712  match(Count, m_Intrinsic<Intrinsic::ctlz>(m_Specific(CmpLHS)))) {
713  IntrinsicInst *II = cast<IntrinsicInst>(Count);
714  // Explicitly clear the 'undef_on_zero' flag.
715  IntrinsicInst *NewI = cast<IntrinsicInst>(II->clone());
716  NewI->setArgOperand(1, ConstantInt::getFalse(NewI->getContext()));
717  Builder.Insert(NewI);
718  return Builder.CreateZExtOrTrunc(NewI, ValueOnZero->getType());
719  }
720 
721  return nullptr;
722 }
723 
724 /// Return true if we find and adjust an icmp+select pattern where the compare
725 /// is with a constant that can be incremented or decremented to match the
726 /// minimum or maximum idiom.
727 static bool adjustMinMax(SelectInst &Sel, ICmpInst &Cmp) {
728  ICmpInst::Predicate Pred = Cmp.getPredicate();
729  Value *CmpLHS = Cmp.getOperand(0);
730  Value *CmpRHS = Cmp.getOperand(1);
731  Value *TrueVal = Sel.getTrueValue();
732  Value *FalseVal = Sel.getFalseValue();
733 
734  // We may move or edit the compare, so make sure the select is the only user.
735  const APInt *CmpC;
736  if (!Cmp.hasOneUse() || !match(CmpRHS, m_APInt(CmpC)))
737  return false;
738 
739  // These transforms only work for selects of integers or vector selects of
740  // integer vectors.
741  Type *SelTy = Sel.getType();
742  auto *SelEltTy = dyn_cast<IntegerType>(SelTy->getScalarType());
743  if (!SelEltTy || SelTy->isVectorTy() != Cmp.getType()->isVectorTy())
744  return false;
745 
746  Constant *AdjustedRHS;
747  if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_SGT)
748  AdjustedRHS = ConstantInt::get(CmpRHS->getType(), *CmpC + 1);
749  else if (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_SLT)
750  AdjustedRHS = ConstantInt::get(CmpRHS->getType(), *CmpC - 1);
751  else
752  return false;
753 
754  // X > C ? X : C+1 --> X < C+1 ? C+1 : X
755  // X < C ? X : C-1 --> X > C-1 ? C-1 : X
756  if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) ||
757  (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) {
758  ; // Nothing to do here. Values match without any sign/zero extension.
759  }
760  // Types do not match. Instead of calculating this with mixed types, promote
761  // all to the larger type. This enables scalar evolution to analyze this
762  // expression.
763  else if (CmpRHS->getType()->getScalarSizeInBits() < SelEltTy->getBitWidth()) {
764  Constant *SextRHS = ConstantExpr::getSExt(AdjustedRHS, SelTy);
765 
766  // X = sext x; x >s c ? X : C+1 --> X = sext x; X <s C+1 ? C+1 : X
767  // X = sext x; x <s c ? X : C-1 --> X = sext x; X >s C-1 ? C-1 : X
768  // X = sext x; x >u c ? X : C+1 --> X = sext x; X <u C+1 ? C+1 : X
769  // X = sext x; x <u c ? X : C-1 --> X = sext x; X >u C-1 ? C-1 : X
770  if (match(TrueVal, m_SExt(m_Specific(CmpLHS))) && SextRHS == FalseVal) {
771  CmpLHS = TrueVal;
772  AdjustedRHS = SextRHS;
773  } else if (match(FalseVal, m_SExt(m_Specific(CmpLHS))) &&
774  SextRHS == TrueVal) {
775  CmpLHS = FalseVal;
776  AdjustedRHS = SextRHS;
777  } else if (Cmp.isUnsigned()) {
778  Constant *ZextRHS = ConstantExpr::getZExt(AdjustedRHS, SelTy);
779  // X = zext x; x >u c ? X : C+1 --> X = zext x; X <u C+1 ? C+1 : X
780  // X = zext x; x <u c ? X : C-1 --> X = zext x; X >u C-1 ? C-1 : X
781  // zext + signed compare cannot be changed:
782  // 0xff <s 0x00, but 0x00ff >s 0x0000
783  if (match(TrueVal, m_ZExt(m_Specific(CmpLHS))) && ZextRHS == FalseVal) {
784  CmpLHS = TrueVal;
785  AdjustedRHS = ZextRHS;
786  } else if (match(FalseVal, m_ZExt(m_Specific(CmpLHS))) &&
787  ZextRHS == TrueVal) {
788  CmpLHS = FalseVal;
789  AdjustedRHS = ZextRHS;
790  } else {
791  return false;
792  }
793  } else {
794  return false;
795  }
796  } else {
797  return false;
798  }
799 
800  Pred = ICmpInst::getSwappedPredicate(Pred);
801  CmpRHS = AdjustedRHS;
802  std::swap(FalseVal, TrueVal);
803  Cmp.setPredicate(Pred);
804  Cmp.setOperand(0, CmpLHS);
805  Cmp.setOperand(1, CmpRHS);
806  Sel.setOperand(1, TrueVal);
807  Sel.setOperand(2, FalseVal);
808  Sel.swapProfMetadata();
809 
810  // Move the compare instruction right before the select instruction. Otherwise
811  // the sext/zext value may be defined after the compare instruction uses it.
812  Cmp.moveBefore(&Sel);
813 
814  return true;
815 }
816 
817 /// If this is an integer min/max (icmp + select) with a constant operand,
818 /// create the canonical icmp for the min/max operation and canonicalize the
819 /// constant to the 'false' operand of the select:
820 /// select (icmp Pred X, C1), C2, X --> select (icmp Pred' X, C2), X, C2
821 /// Note: if C1 != C2, this will change the icmp constant to the existing
822 /// constant operand of the select.
823 static Instruction *
824 canonicalizeMinMaxWithConstant(SelectInst &Sel, ICmpInst &Cmp,
825  InstCombiner::BuilderTy &Builder) {
826  if (!Cmp.hasOneUse() || !isa<Constant>(Cmp.getOperand(1)))
827  return nullptr;
828 
829  // Canonicalize the compare predicate based on whether we have min or max.
830  Value *LHS, *RHS;
831  SelectPatternResult SPR = matchSelectPattern(&Sel, LHS, RHS);
833  return nullptr;
834 
835  // Is this already canonical?
836  ICmpInst::Predicate CanonicalPred = getMinMaxPred(SPR.Flavor);
837  if (Cmp.getOperand(0) == LHS && Cmp.getOperand(1) == RHS &&
838  Cmp.getPredicate() == CanonicalPred)
839  return nullptr;
840 
841  // Create the canonical compare and plug it into the select.
842  Sel.setCondition(Builder.CreateICmp(CanonicalPred, LHS, RHS));
843 
844  // If the select operands did not change, we're done.
845  if (Sel.getTrueValue() == LHS && Sel.getFalseValue() == RHS)
846  return &Sel;
847 
848  // If we are swapping the select operands, swap the metadata too.
849  assert(Sel.getTrueValue() == RHS && Sel.getFalseValue() == LHS &&
850  "Unexpected results from matchSelectPattern");
851  Sel.setTrueValue(LHS);
852  Sel.setFalseValue(RHS);
853  Sel.swapProfMetadata();
854  return &Sel;
855 }
856 
857 /// There are many select variants for each of ABS/NABS.
858 /// In matchSelectPattern(), there are different compare constants, compare
859 /// predicates/operands and select operands.
860 /// In isKnownNegation(), there are different formats of negated operands.
861 /// Canonicalize all these variants to 1 pattern.
862 /// This makes CSE more likely.
863 static Instruction *canonicalizeAbsNabs(SelectInst &Sel, ICmpInst &Cmp,
864  InstCombiner::BuilderTy &Builder) {
865  if (!Cmp.hasOneUse() || !isa<Constant>(Cmp.getOperand(1)))
866  return nullptr;
867 
868  // Choose a sign-bit check for the compare (likely simpler for codegen).
869  // ABS: (X <s 0) ? -X : X
870  // NABS: (X <s 0) ? X : -X
871  Value *LHS, *RHS;
872  SelectPatternFlavor SPF = matchSelectPattern(&Sel, LHS, RHS).Flavor;
873  if (SPF != SelectPatternFlavor::SPF_ABS &&
875  return nullptr;
876 
877  Value *TVal = Sel.getTrueValue();
878  Value *FVal = Sel.getFalseValue();
879  assert(isKnownNegation(TVal, FVal) &&
880  "Unexpected result from matchSelectPattern");
881 
882  // The compare may use the negated abs()/nabs() operand, or it may use
883  // negation in non-canonical form such as: sub A, B.
884  bool CmpUsesNegatedOp = match(Cmp.getOperand(0), m_Neg(m_Specific(TVal))) ||
885  match(Cmp.getOperand(0), m_Neg(m_Specific(FVal)));
886 
887  bool CmpCanonicalized = !CmpUsesNegatedOp &&
888  match(Cmp.getOperand(1), m_ZeroInt()) &&
890  bool RHSCanonicalized = match(RHS, m_Neg(m_Specific(LHS)));
891 
892  // Is this already canonical?
893  if (CmpCanonicalized && RHSCanonicalized)
894  return nullptr;
895 
896  // If RHS is used by other instructions except compare and select, don't
897  // canonicalize it to not increase the instruction count.
898  if (!(RHS->hasOneUse() || (RHS->hasNUses(2) && CmpUsesNegatedOp)))
899  return nullptr;
900 
901  // Create the canonical compare: icmp slt LHS 0.
902  if (!CmpCanonicalized) {
905  if (CmpUsesNegatedOp)
906  Cmp.setOperand(0, LHS);
907  }
908 
909  // Create the canonical RHS: RHS = sub (0, LHS).
910  if (!RHSCanonicalized) {
911  assert(RHS->hasOneUse() && "RHS use number is not right");
912  RHS = Builder.CreateNeg(LHS);
913  if (TVal == LHS) {
914  Sel.setFalseValue(RHS);
915  FVal = RHS;
916  } else {
917  Sel.setTrueValue(RHS);
918  TVal = RHS;
919  }
920  }
921 
922  // If the select operands do not change, we're done.
923  if (SPF == SelectPatternFlavor::SPF_NABS) {
924  if (TVal == LHS)
925  return &Sel;
926  assert(FVal == LHS && "Unexpected results from matchSelectPattern");
927  } else {
928  if (FVal == LHS)
929  return &Sel;
930  assert(TVal == LHS && "Unexpected results from matchSelectPattern");
931  }
932 
933  // We are swapping the select operands, so swap the metadata too.
934  Sel.setTrueValue(FVal);
935  Sel.setFalseValue(TVal);
936  Sel.swapProfMetadata();
937  return &Sel;
938 }
939 
940 /// Visit a SelectInst that has an ICmpInst as its first operand.
941 Instruction *InstCombiner::foldSelectInstWithICmp(SelectInst &SI,
942  ICmpInst *ICI) {
943  Value *TrueVal = SI.getTrueValue();
944  Value *FalseVal = SI.getFalseValue();
945 
946  if (Instruction *NewSel = canonicalizeMinMaxWithConstant(SI, *ICI, Builder))
947  return NewSel;
948 
949  if (Instruction *NewAbs = canonicalizeAbsNabs(SI, *ICI, Builder))
950  return NewAbs;
951 
952  bool Changed = adjustMinMax(SI, *ICI);
953 
954  if (Value *V = foldSelectICmpAnd(SI, ICI, Builder))
955  return replaceInstUsesWith(SI, V);
956 
957  // NOTE: if we wanted to, this is where to detect integer MIN/MAX
958  ICmpInst::Predicate Pred = ICI->getPredicate();
959  Value *CmpLHS = ICI->getOperand(0);
960  Value *CmpRHS = ICI->getOperand(1);
961  if (CmpRHS != CmpLHS && isa<Constant>(CmpRHS)) {
962  if (CmpLHS == TrueVal && Pred == ICmpInst::ICMP_EQ) {
963  // Transform (X == C) ? X : Y -> (X == C) ? C : Y
964  SI.setOperand(1, CmpRHS);
965  Changed = true;
966  } else if (CmpLHS == FalseVal && Pred == ICmpInst::ICMP_NE) {
967  // Transform (X != C) ? Y : X -> (X != C) ? Y : C
968  SI.setOperand(2, CmpRHS);
969  Changed = true;
970  }
971  }
972 
973  // FIXME: This code is nearly duplicated in InstSimplify. Using/refactoring
974  // decomposeBitTestICmp() might help.
975  {
976  unsigned BitWidth =
977  DL.getTypeSizeInBits(TrueVal->getType()->getScalarType());
978  APInt MinSignedValue = APInt::getSignedMinValue(BitWidth);
979  Value *X;
980  const APInt *Y, *C;
981  bool TrueWhenUnset;
982  bool IsBitTest = false;
983  if (ICmpInst::isEquality(Pred) &&
984  match(CmpLHS, m_And(m_Value(X), m_Power2(Y))) &&
985  match(CmpRHS, m_Zero())) {
986  IsBitTest = true;
987  TrueWhenUnset = Pred == ICmpInst::ICMP_EQ;
988  } else if (Pred == ICmpInst::ICMP_SLT && match(CmpRHS, m_Zero())) {
989  X = CmpLHS;
990  Y = &MinSignedValue;
991  IsBitTest = true;
992  TrueWhenUnset = false;
993  } else if (Pred == ICmpInst::ICMP_SGT && match(CmpRHS, m_AllOnes())) {
994  X = CmpLHS;
995  Y = &MinSignedValue;
996  IsBitTest = true;
997  TrueWhenUnset = true;
998  }
999  if (IsBitTest) {
1000  Value *V = nullptr;
1001  // (X & Y) == 0 ? X : X ^ Y --> X & ~Y
1002  if (TrueWhenUnset && TrueVal == X &&
1003  match(FalseVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
1004  V = Builder.CreateAnd(X, ~(*Y));
1005  // (X & Y) != 0 ? X ^ Y : X --> X & ~Y
1006  else if (!TrueWhenUnset && FalseVal == X &&
1007  match(TrueVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
1008  V = Builder.CreateAnd(X, ~(*Y));
1009  // (X & Y) == 0 ? X ^ Y : X --> X | Y
1010  else if (TrueWhenUnset && FalseVal == X &&
1011  match(TrueVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
1012  V = Builder.CreateOr(X, *Y);
1013  // (X & Y) != 0 ? X : X ^ Y --> X | Y
1014  else if (!TrueWhenUnset && TrueVal == X &&
1015  match(FalseVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
1016  V = Builder.CreateOr(X, *Y);
1017 
1018  if (V)
1019  return replaceInstUsesWith(SI, V);
1020  }
1021  }
1022 
1023  if (Instruction *V =
1024  foldSelectICmpAndAnd(SI.getType(), ICI, TrueVal, FalseVal, Builder))
1025  return V;
1026 
1027  if (Value *V = foldSelectICmpAndOr(ICI, TrueVal, FalseVal, Builder))
1028  return replaceInstUsesWith(SI, V);
1029 
1030  if (Value *V = foldSelectCttzCtlz(ICI, TrueVal, FalseVal, Builder))
1031  return replaceInstUsesWith(SI, V);
1032 
1033  if (Value *V = canonicalizeSaturatedSubtract(ICI, TrueVal, FalseVal, Builder))
1034  return replaceInstUsesWith(SI, V);
1035 
1036  return Changed ? &SI : nullptr;
1037 }
1038 
1039 /// SI is a select whose condition is a PHI node (but the two may be in
1040 /// different blocks). See if the true/false values (V) are live in all of the
1041 /// predecessor blocks of the PHI. For example, cases like this can't be mapped:
1042 ///
1043 /// X = phi [ C1, BB1], [C2, BB2]
1044 /// Y = add
1045 /// Z = select X, Y, 0
1046 ///
1047 /// because Y is not live in BB1/BB2.
1048 static bool canSelectOperandBeMappingIntoPredBlock(const Value *V,
1049  const SelectInst &SI) {
1050  // If the value is a non-instruction value like a constant or argument, it
1051  // can always be mapped.
1052  const Instruction *I = dyn_cast<Instruction>(V);
1053  if (!I) return true;
1054 
1055  // If V is a PHI node defined in the same block as the condition PHI, we can
1056  // map the arguments.
1057  const PHINode *CondPHI = cast<PHINode>(SI.getCondition());
1058 
1059  if (const PHINode *VP = dyn_cast<PHINode>(I))
1060  if (VP->getParent() == CondPHI->getParent())
1061  return true;
1062 
1063  // Otherwise, if the PHI and select are defined in the same block and if V is
1064  // defined in a different block, then we can transform it.
1065  if (SI.getParent() == CondPHI->getParent() &&
1066  I->getParent() != CondPHI->getParent())
1067  return true;
1068 
1069  // Otherwise we have a 'hard' case and we can't tell without doing more
1070  // detailed dominator based analysis, punt.
1071  return false;
1072 }
1073 
1074 /// We have an SPF (e.g. a min or max) of an SPF of the form:
1075 /// SPF2(SPF1(A, B), C)
1076 Instruction *InstCombiner::foldSPFofSPF(Instruction *Inner,
1077  SelectPatternFlavor SPF1,
1078  Value *A, Value *B,
1079  Instruction &Outer,
1080  SelectPatternFlavor SPF2, Value *C) {
1081  if (Outer.getType() != Inner->getType())
1082  return nullptr;
1083 
1084  if (C == A || C == B) {
1085  // MAX(MAX(A, B), B) -> MAX(A, B)
1086  // MIN(MIN(a, b), a) -> MIN(a, b)
1087  // TODO: This could be done in instsimplify.
1088  if (SPF1 == SPF2 && SelectPatternResult::isMinOrMax(SPF1))
1089  return replaceInstUsesWith(Outer, Inner);
1090 
1091  // MAX(MIN(a, b), a) -> a
1092  // MIN(MAX(a, b), a) -> a
1093  // TODO: This could be done in instsimplify.
1094  if ((SPF1 == SPF_SMIN && SPF2 == SPF_SMAX) ||
1095  (SPF1 == SPF_SMAX && SPF2 == SPF_SMIN) ||
1096  (SPF1 == SPF_UMIN && SPF2 == SPF_UMAX) ||
1097  (SPF1 == SPF_UMAX && SPF2 == SPF_UMIN))
1098  return replaceInstUsesWith(Outer, C);
1099  }
1100 
1101  if (SPF1 == SPF2) {
1102  const APInt *CB, *CC;
1103  if (match(B, m_APInt(CB)) && match(C, m_APInt(CC))) {
1104  // MIN(MIN(A, 23), 97) -> MIN(A, 23)
1105  // MAX(MAX(A, 97), 23) -> MAX(A, 97)
1106  // TODO: This could be done in instsimplify.
1107  if ((SPF1 == SPF_UMIN && CB->ule(*CC)) ||
1108  (SPF1 == SPF_SMIN && CB->sle(*CC)) ||
1109  (SPF1 == SPF_UMAX && CB->uge(*CC)) ||
1110  (SPF1 == SPF_SMAX && CB->sge(*CC)))
1111  return replaceInstUsesWith(Outer, Inner);
1112 
1113  // MIN(MIN(A, 97), 23) -> MIN(A, 23)
1114  // MAX(MAX(A, 23), 97) -> MAX(A, 97)
1115  if ((SPF1 == SPF_UMIN && CB->ugt(*CC)) ||
1116  (SPF1 == SPF_SMIN && CB->sgt(*CC)) ||
1117  (SPF1 == SPF_UMAX && CB->ult(*CC)) ||
1118  (SPF1 == SPF_SMAX && CB->slt(*CC))) {
1119  Outer.replaceUsesOfWith(Inner, A);
1120  return &Outer;
1121  }
1122  }
1123  }
1124 
1125  // ABS(ABS(X)) -> ABS(X)
1126  // NABS(NABS(X)) -> NABS(X)
1127  // TODO: This could be done in instsimplify.
1128  if (SPF1 == SPF2 && (SPF1 == SPF_ABS || SPF1 == SPF_NABS)) {
1129  return replaceInstUsesWith(Outer, Inner);
1130  }
1131 
1132  // ABS(NABS(X)) -> ABS(X)
1133  // NABS(ABS(X)) -> NABS(X)
1134  if ((SPF1 == SPF_ABS && SPF2 == SPF_NABS) ||
1135  (SPF1 == SPF_NABS && SPF2 == SPF_ABS)) {
1136  SelectInst *SI = cast<SelectInst>(Inner);
1137  Value *NewSI =
1138  Builder.CreateSelect(SI->getCondition(), SI->getFalseValue(),
1139  SI->getTrueValue(), SI->getName(), SI);
1140  return replaceInstUsesWith(Outer, NewSI);
1141  }
1142 
1143  auto IsFreeOrProfitableToInvert =
1144  [&](Value *V, Value *&NotV, bool &ElidesXor) {
1145  if (match(V, m_Not(m_Value(NotV)))) {
1146  // If V has at most 2 uses then we can get rid of the xor operation
1147  // entirely.
1148  ElidesXor |= !V->hasNUsesOrMore(3);
1149  return true;
1150  }
1151 
1152  if (IsFreeToInvert(V, !V->hasNUsesOrMore(3))) {
1153  NotV = nullptr;
1154  return true;
1155  }
1156 
1157  return false;
1158  };
1159 
1160  Value *NotA, *NotB, *NotC;
1161  bool ElidesXor = false;
1162 
1163  // MIN(MIN(~A, ~B), ~C) == ~MAX(MAX(A, B), C)
1164  // MIN(MAX(~A, ~B), ~C) == ~MAX(MIN(A, B), C)
1165  // MAX(MIN(~A, ~B), ~C) == ~MIN(MAX(A, B), C)
1166  // MAX(MAX(~A, ~B), ~C) == ~MIN(MIN(A, B), C)
1167  //
1168  // This transform is performance neutral if we can elide at least one xor from
1169  // the set of three operands, since we'll be tacking on an xor at the very
1170  // end.
1171  if (SelectPatternResult::isMinOrMax(SPF1) &&
1173  IsFreeOrProfitableToInvert(A, NotA, ElidesXor) &&
1174  IsFreeOrProfitableToInvert(B, NotB, ElidesXor) &&
1175  IsFreeOrProfitableToInvert(C, NotC, ElidesXor) && ElidesXor) {
1176  if (!NotA)
1177  NotA = Builder.CreateNot(A);
1178  if (!NotB)
1179  NotB = Builder.CreateNot(B);
1180  if (!NotC)
1181  NotC = Builder.CreateNot(C);
1182 
1183  Value *NewInner = createMinMax(Builder, getInverseMinMaxFlavor(SPF1), NotA,
1184  NotB);
1185  Value *NewOuter = Builder.CreateNot(
1186  createMinMax(Builder, getInverseMinMaxFlavor(SPF2), NewInner, NotC));
1187  return replaceInstUsesWith(Outer, NewOuter);
1188  }
1189 
1190  return nullptr;
1191 }
1192 
1193 /// Turn select C, (X + Y), (X - Y) --> (X + (select C, Y, (-Y))).
1194 /// This is even legal for FP.
1195 static Instruction *foldAddSubSelect(SelectInst &SI,
1196  InstCombiner::BuilderTy &Builder) {
1197  Value *CondVal = SI.getCondition();
1198  Value *TrueVal = SI.getTrueValue();
1199  Value *FalseVal = SI.getFalseValue();
1200  auto *TI = dyn_cast<Instruction>(TrueVal);
1201  auto *FI = dyn_cast<Instruction>(FalseVal);
1202  if (!TI || !FI || !TI->hasOneUse() || !FI->hasOneUse())
1203  return nullptr;
1204 
1205  Instruction *AddOp = nullptr, *SubOp = nullptr;
1206  if ((TI->getOpcode() == Instruction::Sub &&
1207  FI->getOpcode() == Instruction::Add) ||
1208  (TI->getOpcode() == Instruction::FSub &&
1209  FI->getOpcode() == Instruction::FAdd)) {
1210  AddOp = FI;
1211  SubOp = TI;
1212  } else if ((FI->getOpcode() == Instruction::Sub &&
1213  TI->getOpcode() == Instruction::Add) ||
1214  (FI->getOpcode() == Instruction::FSub &&
1215  TI->getOpcode() == Instruction::FAdd)) {
1216  AddOp = TI;
1217  SubOp = FI;
1218  }
1219 
1220  if (AddOp) {
1221  Value *OtherAddOp = nullptr;
1222  if (SubOp->getOperand(0) == AddOp->getOperand(0)) {
1223  OtherAddOp = AddOp->getOperand(1);
1224  } else if (SubOp->getOperand(0) == AddOp->getOperand(1)) {
1225  OtherAddOp = AddOp->getOperand(0);
1226  }
1227 
1228  if (OtherAddOp) {
1229  // So at this point we know we have (Y -> OtherAddOp):
1230  // select C, (add X, Y), (sub X, Z)
1231  Value *NegVal; // Compute -Z
1232  if (SI.getType()->isFPOrFPVectorTy()) {
1233  NegVal = Builder.CreateFNeg(SubOp->getOperand(1));
1234  if (Instruction *NegInst = dyn_cast<Instruction>(NegVal)) {
1235  FastMathFlags Flags = AddOp->getFastMathFlags();
1236  Flags &= SubOp->getFastMathFlags();
1237  NegInst->setFastMathFlags(Flags);
1238  }
1239  } else {
1240  NegVal = Builder.CreateNeg(SubOp->getOperand(1));
1241  }
1242 
1243  Value *NewTrueOp = OtherAddOp;
1244  Value *NewFalseOp = NegVal;
1245  if (AddOp != TI)
1246  std::swap(NewTrueOp, NewFalseOp);
1247  Value *NewSel = Builder.CreateSelect(CondVal, NewTrueOp, NewFalseOp,
1248  SI.getName() + ".p", &SI);
1249 
1250  if (SI.getType()->isFPOrFPVectorTy()) {
1251  Instruction *RI =
1252  BinaryOperator::CreateFAdd(SubOp->getOperand(0), NewSel);
1253 
1254  FastMathFlags Flags = AddOp->getFastMathFlags();
1255  Flags &= SubOp->getFastMathFlags();
1256  RI->setFastMathFlags(Flags);
1257  return RI;
1258  } else
1259  return BinaryOperator::CreateAdd(SubOp->getOperand(0), NewSel);
1260  }
1261  }
1262  return nullptr;
1263 }
1264 
1265 Instruction *InstCombiner::foldSelectExtConst(SelectInst &Sel) {
1266  Constant *C;
1267  if (!match(Sel.getTrueValue(), m_Constant(C)) &&
1268  !match(Sel.getFalseValue(), m_Constant(C)))
1269  return nullptr;
1270 
1271  Instruction *ExtInst;
1272  if (!match(Sel.getTrueValue(), m_Instruction(ExtInst)) &&
1273  !match(Sel.getFalseValue(), m_Instruction(ExtInst)))
1274  return nullptr;
1275 
1276  auto ExtOpcode = ExtInst->getOpcode();
1277  if (ExtOpcode != Instruction::ZExt && ExtOpcode != Instruction::SExt)
1278  return nullptr;
1279 
1280  // If we are extending from a boolean type or if we can create a select that
1281  // has the same size operands as its condition, try to narrow the select.
1282  Value *X = ExtInst->getOperand(0);
1283  Type *SmallType = X->getType();
1284  Value *Cond = Sel.getCondition();
1285  auto *Cmp = dyn_cast<CmpInst>(Cond);
1286  if (!SmallType->isIntOrIntVectorTy(1) &&
1287  (!Cmp || Cmp->getOperand(0)->getType() != SmallType))
1288  return nullptr;
1289 
1290  // If the constant is the same after truncation to the smaller type and
1291  // extension to the original type, we can narrow the select.
1292  Type *SelType = Sel.getType();
1293  Constant *TruncC = ConstantExpr::getTrunc(C, SmallType);
1294  Constant *ExtC = ConstantExpr::getCast(ExtOpcode, TruncC, SelType);
1295  if (ExtC == C) {
1296  Value *TruncCVal = cast<Value>(TruncC);
1297  if (ExtInst == Sel.getFalseValue())
1298  std::swap(X, TruncCVal);
1299 
1300  // select Cond, (ext X), C --> ext(select Cond, X, C')
1301  // select Cond, C, (ext X) --> ext(select Cond, C', X)
1302  Value *NewSel = Builder.CreateSelect(Cond, X, TruncCVal, "narrow", &Sel);
1303  return CastInst::Create(Instruction::CastOps(ExtOpcode), NewSel, SelType);
1304  }
1305 
1306  // If one arm of the select is the extend of the condition, replace that arm
1307  // with the extension of the appropriate known bool value.
1308  if (Cond == X) {
1309  if (ExtInst == Sel.getTrueValue()) {
1310  // select X, (sext X), C --> select X, -1, C
1311  // select X, (zext X), C --> select X, 1, C
1312  Constant *One = ConstantInt::getTrue(SmallType);
1313  Constant *AllOnesOrOne = ConstantExpr::getCast(ExtOpcode, One, SelType);
1314  return SelectInst::Create(Cond, AllOnesOrOne, C, "", nullptr, &Sel);
1315  } else {
1316  // select X, C, (sext X) --> select X, C, 0
1317  // select X, C, (zext X) --> select X, C, 0
1318  Constant *Zero = ConstantInt::getNullValue(SelType);
1319  return SelectInst::Create(Cond, C, Zero, "", nullptr, &Sel);
1320  }
1321  }
1322 
1323  return nullptr;
1324 }
1325 
1326 /// Try to transform a vector select with a constant condition vector into a
1327 /// shuffle for easier combining with other shuffles and insert/extract.
1328 static Instruction *canonicalizeSelectToShuffle(SelectInst &SI) {
1329  Value *CondVal = SI.getCondition();
1330  Constant *CondC;
1331  if (!CondVal->getType()->isVectorTy() || !match(CondVal, m_Constant(CondC)))
1332  return nullptr;
1333 
1334  unsigned NumElts = CondVal->getType()->getVectorNumElements();
1336  Mask.reserve(NumElts);
1337  Type *Int32Ty = Type::getInt32Ty(CondVal->getContext());
1338  for (unsigned i = 0; i != NumElts; ++i) {
1339  Constant *Elt = CondC->getAggregateElement(i);
1340  if (!Elt)
1341  return nullptr;
1342 
1343  if (Elt->isOneValue()) {
1344  // If the select condition element is true, choose from the 1st vector.
1345  Mask.push_back(ConstantInt::get(Int32Ty, i));
1346  } else if (Elt->isNullValue()) {
1347  // If the select condition element is false, choose from the 2nd vector.
1348  Mask.push_back(ConstantInt::get(Int32Ty, i + NumElts));
1349  } else if (isa<UndefValue>(Elt)) {
1350  // Undef in a select condition (choose one of the operands) does not mean
1351  // the same thing as undef in a shuffle mask (any value is acceptable), so
1352  // give up.
1353  return nullptr;
1354  } else {
1355  // Bail out on a constant expression.
1356  return nullptr;
1357  }
1358  }
1359 
1360  return new ShuffleVectorInst(SI.getTrueValue(), SI.getFalseValue(),
1361  ConstantVector::get(Mask));
1362 }
1363 
1364 /// Reuse bitcasted operands between a compare and select:
1365 /// select (cmp (bitcast C), (bitcast D)), (bitcast' C), (bitcast' D) -->
1366 /// bitcast (select (cmp (bitcast C), (bitcast D)), (bitcast C), (bitcast D))
1367 static Instruction *foldSelectCmpBitcasts(SelectInst &Sel,
1368  InstCombiner::BuilderTy &Builder) {
1369  Value *Cond = Sel.getCondition();
1370  Value *TVal = Sel.getTrueValue();
1371  Value *FVal = Sel.getFalseValue();
1372 
1373  CmpInst::Predicate Pred;
1374  Value *A, *B;
1375  if (!match(Cond, m_Cmp(Pred, m_Value(A), m_Value(B))))
1376  return nullptr;
1377 
1378  // The select condition is a compare instruction. If the select's true/false
1379  // values are already the same as the compare operands, there's nothing to do.
1380  if (TVal == A || TVal == B || FVal == A || FVal == B)
1381  return nullptr;
1382 
1383  Value *C, *D;
1384  if (!match(A, m_BitCast(m_Value(C))) || !match(B, m_BitCast(m_Value(D))))
1385  return nullptr;
1386 
1387  // select (cmp (bitcast C), (bitcast D)), (bitcast TSrc), (bitcast FSrc)
1388  Value *TSrc, *FSrc;
1389  if (!match(TVal, m_BitCast(m_Value(TSrc))) ||
1390  !match(FVal, m_BitCast(m_Value(FSrc))))
1391  return nullptr;
1392 
1393  // If the select true/false values are *different bitcasts* of the same source
1394  // operands, make the select operands the same as the compare operands and
1395  // cast the result. This is the canonical select form for min/max.
1396  Value *NewSel;
1397  if (TSrc == C && FSrc == D) {
1398  // select (cmp (bitcast C), (bitcast D)), (bitcast' C), (bitcast' D) -->
1399  // bitcast (select (cmp A, B), A, B)
1400  NewSel = Builder.CreateSelect(Cond, A, B, "", &Sel);
1401  } else if (TSrc == D && FSrc == C) {
1402  // select (cmp (bitcast C), (bitcast D)), (bitcast' D), (bitcast' C) -->
1403  // bitcast (select (cmp A, B), B, A)
1404  NewSel = Builder.CreateSelect(Cond, B, A, "", &Sel);
1405  } else {
1406  return nullptr;
1407  }
1408  return CastInst::CreateBitOrPointerCast(NewSel, Sel.getType());
1409 }
1410 
1411 /// Try to eliminate select instructions that test the returned flag of cmpxchg
1412 /// instructions.
1413 ///
1414 /// If a select instruction tests the returned flag of a cmpxchg instruction and
1415 /// selects between the returned value of the cmpxchg instruction its compare
1416 /// operand, the result of the select will always be equal to its false value.
1417 /// For example:
1418 ///
1419 /// %0 = cmpxchg i64* %ptr, i64 %compare, i64 %new_value seq_cst seq_cst
1420 /// %1 = extractvalue { i64, i1 } %0, 1
1421 /// %2 = extractvalue { i64, i1 } %0, 0
1422 /// %3 = select i1 %1, i64 %compare, i64 %2
1423 /// ret i64 %3
1424 ///
1425 /// The returned value of the cmpxchg instruction (%2) is the original value
1426 /// located at %ptr prior to any update. If the cmpxchg operation succeeds, %2
1427 /// must have been equal to %compare. Thus, the result of the select is always
1428 /// equal to %2, and the code can be simplified to:
1429 ///
1430 /// %0 = cmpxchg i64* %ptr, i64 %compare, i64 %new_value seq_cst seq_cst
1431 /// %1 = extractvalue { i64, i1 } %0, 0
1432 /// ret i64 %1
1433 ///
1434 static Instruction *foldSelectCmpXchg(SelectInst &SI) {
1435  // A helper that determines if V is an extractvalue instruction whose
1436  // aggregate operand is a cmpxchg instruction and whose single index is equal
1437  // to I. If such conditions are true, the helper returns the cmpxchg
1438  // instruction; otherwise, a nullptr is returned.
1439  auto isExtractFromCmpXchg = [](Value *V, unsigned I) -> AtomicCmpXchgInst * {
1440  auto *Extract = dyn_cast<ExtractValueInst>(V);
1441  if (!Extract)
1442  return nullptr;
1443  if (Extract->getIndices()[0] != I)
1444  return nullptr;
1445  return dyn_cast<AtomicCmpXchgInst>(Extract->getAggregateOperand());
1446  };
1447 
1448  // If the select has a single user, and this user is a select instruction that
1449  // we can simplify, skip the cmpxchg simplification for now.
1450  if (SI.hasOneUse())
1451  if (auto *Select = dyn_cast<SelectInst>(SI.user_back()))
1452  if (Select->getCondition() == SI.getCondition())
1453  if (Select->getFalseValue() == SI.getTrueValue() ||
1454  Select->getTrueValue() == SI.getFalseValue())
1455  return nullptr;
1456 
1457  // Ensure the select condition is the returned flag of a cmpxchg instruction.
1458  auto *CmpXchg = isExtractFromCmpXchg(SI.getCondition(), 1);
1459  if (!CmpXchg)
1460  return nullptr;
1461 
1462  // Check the true value case: The true value of the select is the returned
1463  // value of the same cmpxchg used by the condition, and the false value is the
1464  // cmpxchg instruction's compare operand.
1465  if (auto *X = isExtractFromCmpXchg(SI.getTrueValue(), 0))
1466  if (X == CmpXchg && X->getCompareOperand() == SI.getFalseValue()) {
1467  SI.setTrueValue(SI.getFalseValue());
1468  return &SI;
1469  }
1470 
1471  // Check the false value case: The false value of the select is the returned
1472  // value of the same cmpxchg used by the condition, and the true value is the
1473  // cmpxchg instruction's compare operand.
1474  if (auto *X = isExtractFromCmpXchg(SI.getFalseValue(), 0))
1475  if (X == CmpXchg && X->getCompareOperand() == SI.getTrueValue()) {
1476  SI.setTrueValue(SI.getFalseValue());
1477  return &SI;
1478  }
1479 
1480  return nullptr;
1481 }
1482 
1483 /// Reduce a sequence of min/max with a common operand.
1484 static Instruction *factorizeMinMaxTree(SelectPatternFlavor SPF, Value *LHS,
1485  Value *RHS,
1486  InstCombiner::BuilderTy &Builder) {
1487  assert(SelectPatternResult::isMinOrMax(SPF) && "Expected a min/max");
1488  // TODO: Allow FP min/max with nnan/nsz.
1489  if (!LHS->getType()->isIntOrIntVectorTy())
1490  return nullptr;
1491 
1492  // Match 3 of the same min/max ops. Example: umin(umin(), umin()).
1493  Value *A, *B, *C, *D;
1494  SelectPatternResult L = matchSelectPattern(LHS, A, B);
1495  SelectPatternResult R = matchSelectPattern(RHS, C, D);
1496  if (SPF != L.Flavor || L.Flavor != R.Flavor)
1497  return nullptr;
1498 
1499  // Look for a common operand. The use checks are different than usual because
1500  // a min/max pattern typically has 2 uses of each op: 1 by the cmp and 1 by
1501  // the select.
1502  Value *MinMaxOp = nullptr;
1503  Value *ThirdOp = nullptr;
1504  if (!LHS->hasNUsesOrMore(3) && RHS->hasNUsesOrMore(3)) {
1505  // If the LHS is only used in this chain and the RHS is used outside of it,
1506  // reuse the RHS min/max because that will eliminate the LHS.
1507  if (D == A || C == A) {
1508  // min(min(a, b), min(c, a)) --> min(min(c, a), b)
1509  // min(min(a, b), min(a, d)) --> min(min(a, d), b)
1510  MinMaxOp = RHS;
1511  ThirdOp = B;
1512  } else if (D == B || C == B) {
1513  // min(min(a, b), min(c, b)) --> min(min(c, b), a)
1514  // min(min(a, b), min(b, d)) --> min(min(b, d), a)
1515  MinMaxOp = RHS;
1516  ThirdOp = A;
1517  }
1518  } else if (!RHS->hasNUsesOrMore(3)) {
1519  // Reuse the LHS. This will eliminate the RHS.
1520  if (D == A || D == B) {
1521  // min(min(a, b), min(c, a)) --> min(min(a, b), c)
1522  // min(min(a, b), min(c, b)) --> min(min(a, b), c)
1523  MinMaxOp = LHS;
1524  ThirdOp = C;
1525  } else if (C == A || C == B) {
1526  // min(min(a, b), min(b, d)) --> min(min(a, b), d)
1527  // min(min(a, b), min(c, b)) --> min(min(a, b), d)
1528  MinMaxOp = LHS;
1529  ThirdOp = D;
1530  }
1531  }
1532  if (!MinMaxOp || !ThirdOp)
1533  return nullptr;
1534 
1536  Value *CmpABC = Builder.CreateICmp(P, MinMaxOp, ThirdOp);
1537  return SelectInst::Create(CmpABC, MinMaxOp, ThirdOp);
1538 }
1539 
1541  Value *CondVal = SI.getCondition();
1542  Value *TrueVal = SI.getTrueValue();
1543  Value *FalseVal = SI.getFalseValue();
1544  Type *SelType = SI.getType();
1545 
1546  // FIXME: Remove this workaround when freeze related patches are done.
1547  // For select with undef operand which feeds into an equality comparison,
1548  // don't simplify it so loop unswitch can know the equality comparison
1549  // may have an undef operand. This is a workaround for PR31652 caused by
1550  // descrepancy about branch on undef between LoopUnswitch and GVN.
1551  if (isa<UndefValue>(TrueVal) || isa<UndefValue>(FalseVal)) {
1552  if (llvm::any_of(SI.users(), [&](User *U) {
1553  ICmpInst *CI = dyn_cast<ICmpInst>(U);
1554  if (CI && CI->isEquality())
1555  return true;
1556  return false;
1557  })) {
1558  return nullptr;
1559  }
1560  }
1561 
1562  if (Value *V = SimplifySelectInst(CondVal, TrueVal, FalseVal,
1563  SQ.getWithInstruction(&SI)))
1564  return replaceInstUsesWith(SI, V);
1565 
1566  if (Instruction *I = canonicalizeSelectToShuffle(SI))
1567  return I;
1568 
1569  // Canonicalize a one-use integer compare with a non-canonical predicate by
1570  // inverting the predicate and swapping the select operands. This matches a
1571  // compare canonicalization for conditional branches.
1572  // TODO: Should we do the same for FP compares?
1573  CmpInst::Predicate Pred;
1574  if (match(CondVal, m_OneUse(m_ICmp(Pred, m_Value(), m_Value()))) &&
1575  !isCanonicalPredicate(Pred)) {
1576  // Swap true/false values and condition.
1577  CmpInst *Cond = cast<CmpInst>(CondVal);
1579  SI.setOperand(1, FalseVal);
1580  SI.setOperand(2, TrueVal);
1581  SI.swapProfMetadata();
1582  Worklist.Add(Cond);
1583  return &SI;
1584  }
1585 
1586  if (SelType->isIntOrIntVectorTy(1) &&
1587  TrueVal->getType() == CondVal->getType()) {
1588  if (match(TrueVal, m_One())) {
1589  // Change: A = select B, true, C --> A = or B, C
1590  return BinaryOperator::CreateOr(CondVal, FalseVal);
1591  }
1592  if (match(TrueVal, m_Zero())) {
1593  // Change: A = select B, false, C --> A = and !B, C
1594  Value *NotCond = Builder.CreateNot(CondVal, "not." + CondVal->getName());
1595  return BinaryOperator::CreateAnd(NotCond, FalseVal);
1596  }
1597  if (match(FalseVal, m_Zero())) {
1598  // Change: A = select B, C, false --> A = and B, C
1599  return BinaryOperator::CreateAnd(CondVal, TrueVal);
1600  }
1601  if (match(FalseVal, m_One())) {
1602  // Change: A = select B, C, true --> A = or !B, C
1603  Value *NotCond = Builder.CreateNot(CondVal, "not." + CondVal->getName());
1604  return BinaryOperator::CreateOr(NotCond, TrueVal);
1605  }
1606 
1607  // select a, a, b -> a | b
1608  // select a, b, a -> a & b
1609  if (CondVal == TrueVal)
1610  return BinaryOperator::CreateOr(CondVal, FalseVal);
1611  if (CondVal == FalseVal)
1612  return BinaryOperator::CreateAnd(CondVal, TrueVal);
1613 
1614  // select a, ~a, b -> (~a) & b
1615  // select a, b, ~a -> (~a) | b
1616  if (match(TrueVal, m_Not(m_Specific(CondVal))))
1617  return BinaryOperator::CreateAnd(TrueVal, FalseVal);
1618  if (match(FalseVal, m_Not(m_Specific(CondVal))))
1619  return BinaryOperator::CreateOr(TrueVal, FalseVal);
1620  }
1621 
1622  // Selecting between two integer or vector splat integer constants?
1623  //
1624  // Note that we don't handle a scalar select of vectors:
1625  // select i1 %c, <2 x i8> <1, 1>, <2 x i8> <0, 0>
1626  // because that may need 3 instructions to splat the condition value:
1627  // extend, insertelement, shufflevector.
1628  if (SelType->isIntOrIntVectorTy() &&
1629  CondVal->getType()->isVectorTy() == SelType->isVectorTy()) {
1630  // select C, 1, 0 -> zext C to int
1631  if (match(TrueVal, m_One()) && match(FalseVal, m_Zero()))
1632  return new ZExtInst(CondVal, SelType);
1633 
1634  // select C, -1, 0 -> sext C to int
1635  if (match(TrueVal, m_AllOnes()) && match(FalseVal, m_Zero()))
1636  return new SExtInst(CondVal, SelType);
1637 
1638  // select C, 0, 1 -> zext !C to int
1639  if (match(TrueVal, m_Zero()) && match(FalseVal, m_One())) {
1640  Value *NotCond = Builder.CreateNot(CondVal, "not." + CondVal->getName());
1641  return new ZExtInst(NotCond, SelType);
1642  }
1643 
1644  // select C, 0, -1 -> sext !C to int
1645  if (match(TrueVal, m_Zero()) && match(FalseVal, m_AllOnes())) {
1646  Value *NotCond = Builder.CreateNot(CondVal, "not." + CondVal->getName());
1647  return new SExtInst(NotCond, SelType);
1648  }
1649  }
1650 
1651  // See if we are selecting two values based on a comparison of the two values.
1652  if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) {
1653  if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) {
1654  // Transform (X == Y) ? X : Y -> Y
1655  if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) {
1656  // This is not safe in general for floating point:
1657  // consider X== -0, Y== +0.
1658  // It becomes safe if either operand is a nonzero constant.
1659  ConstantFP *CFPt, *CFPf;
1660  if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
1661  !CFPt->getValueAPF().isZero()) ||
1662  ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
1663  !CFPf->getValueAPF().isZero()))
1664  return replaceInstUsesWith(SI, FalseVal);
1665  }
1666  // Transform (X une Y) ? X : Y -> X
1667  if (FCI->getPredicate() == FCmpInst::FCMP_UNE) {
1668  // This is not safe in general for floating point:
1669  // consider X== -0, Y== +0.
1670  // It becomes safe if either operand is a nonzero constant.
1671  ConstantFP *CFPt, *CFPf;
1672  if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
1673  !CFPt->getValueAPF().isZero()) ||
1674  ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
1675  !CFPf->getValueAPF().isZero()))
1676  return replaceInstUsesWith(SI, TrueVal);
1677  }
1678 
1679  // Canonicalize to use ordered comparisons by swapping the select
1680  // operands.
1681  //
1682  // e.g.
1683  // (X ugt Y) ? X : Y -> (X ole Y) ? Y : X
1684  if (FCI->hasOneUse() && FCmpInst::isUnordered(FCI->getPredicate())) {
1685  FCmpInst::Predicate InvPred = FCI->getInversePredicate();
1686  IRBuilder<>::FastMathFlagGuard FMFG(Builder);
1687  Builder.setFastMathFlags(FCI->getFastMathFlags());
1688  Value *NewCond = Builder.CreateFCmp(InvPred, TrueVal, FalseVal,
1689  FCI->getName() + ".inv");
1690 
1691  return SelectInst::Create(NewCond, FalseVal, TrueVal,
1692  SI.getName() + ".p");
1693  }
1694 
1695  // NOTE: if we wanted to, this is where to detect MIN/MAX
1696  } else if (FCI->getOperand(0) == FalseVal && FCI->getOperand(1) == TrueVal){
1697  // Transform (X == Y) ? Y : X -> X
1698  if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) {
1699  // This is not safe in general for floating point:
1700  // consider X== -0, Y== +0.
1701  // It becomes safe if either operand is a nonzero constant.
1702  ConstantFP *CFPt, *CFPf;
1703  if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
1704  !CFPt->getValueAPF().isZero()) ||
1705  ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
1706  !CFPf->getValueAPF().isZero()))
1707  return replaceInstUsesWith(SI, FalseVal);
1708  }
1709  // Transform (X une Y) ? Y : X -> Y
1710  if (FCI->getPredicate() == FCmpInst::FCMP_UNE) {
1711  // This is not safe in general for floating point:
1712  // consider X== -0, Y== +0.
1713  // It becomes safe if either operand is a nonzero constant.
1714  ConstantFP *CFPt, *CFPf;
1715  if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
1716  !CFPt->getValueAPF().isZero()) ||
1717  ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
1718  !CFPf->getValueAPF().isZero()))
1719  return replaceInstUsesWith(SI, TrueVal);
1720  }
1721 
1722  // Canonicalize to use ordered comparisons by swapping the select
1723  // operands.
1724  //
1725  // e.g.
1726  // (X ugt Y) ? X : Y -> (X ole Y) ? X : Y
1727  if (FCI->hasOneUse() && FCmpInst::isUnordered(FCI->getPredicate())) {
1728  FCmpInst::Predicate InvPred = FCI->getInversePredicate();
1729  IRBuilder<>::FastMathFlagGuard FMFG(Builder);
1730  Builder.setFastMathFlags(FCI->getFastMathFlags());
1731  Value *NewCond = Builder.CreateFCmp(InvPred, FalseVal, TrueVal,
1732  FCI->getName() + ".inv");
1733 
1734  return SelectInst::Create(NewCond, FalseVal, TrueVal,
1735  SI.getName() + ".p");
1736  }
1737 
1738  // NOTE: if we wanted to, this is where to detect MIN/MAX
1739  }
1740 
1741  // Canonicalize select with fcmp to fabs(). -0.0 makes this tricky. We need
1742  // fast-math-flags (nsz) or fsub with +0.0 (not fneg) for this to work. We
1743  // also require nnan because we do not want to unintentionally change the
1744  // sign of a NaN value.
1745  Value *X = FCI->getOperand(0);
1746  FCmpInst::Predicate Pred = FCI->getPredicate();
1747  if (match(FCI->getOperand(1), m_AnyZeroFP()) && FCI->hasNoNaNs()) {
1748  // (X <= +/-0.0) ? (0.0 - X) : X --> fabs(X)
1749  // (X > +/-0.0) ? X : (0.0 - X) --> fabs(X)
1750  if ((X == FalseVal && Pred == FCmpInst::FCMP_OLE &&
1751  match(TrueVal, m_FSub(m_PosZeroFP(), m_Specific(X)))) ||
1752  (X == TrueVal && Pred == FCmpInst::FCMP_OGT &&
1753  match(FalseVal, m_FSub(m_PosZeroFP(), m_Specific(X))))) {
1754  Value *Fabs = Builder.CreateIntrinsic(Intrinsic::fabs, { X }, FCI);
1755  return replaceInstUsesWith(SI, Fabs);
1756  }
1757  // With nsz:
1758  // (X < +/-0.0) ? -X : X --> fabs(X)
1759  // (X <= +/-0.0) ? -X : X --> fabs(X)
1760  // (X > +/-0.0) ? X : -X --> fabs(X)
1761  // (X >= +/-0.0) ? X : -X --> fabs(X)
1762  if (FCI->hasNoSignedZeros() &&
1763  ((X == FalseVal && match(TrueVal, m_FNeg(m_Specific(X))) &&
1764  (Pred == FCmpInst::FCMP_OLT || Pred == FCmpInst::FCMP_OLE)) ||
1765  (X == TrueVal && match(FalseVal, m_FNeg(m_Specific(X))) &&
1766  (Pred == FCmpInst::FCMP_OGT || Pred == FCmpInst::FCMP_OGE)))) {
1767  Value *Fabs = Builder.CreateIntrinsic(Intrinsic::fabs, { X }, FCI);
1768  return replaceInstUsesWith(SI, Fabs);
1769  }
1770  }
1771  }
1772 
1773  // See if we are selecting two values based on a comparison of the two values.
1774  if (ICmpInst *ICI = dyn_cast<ICmpInst>(CondVal))
1775  if (Instruction *Result = foldSelectInstWithICmp(SI, ICI))
1776  return Result;
1777 
1778  if (Instruction *Add = foldAddSubSelect(SI, Builder))
1779  return Add;
1780 
1781  // Turn (select C, (op X, Y), (op X, Z)) -> (op X, (select C, Y, Z))
1782  auto *TI = dyn_cast<Instruction>(TrueVal);
1783  auto *FI = dyn_cast<Instruction>(FalseVal);
1784  if (TI && FI && TI->getOpcode() == FI->getOpcode())
1785  if (Instruction *IV = foldSelectOpOp(SI, TI, FI))
1786  return IV;
1787 
1788  if (Instruction *I = foldSelectExtConst(SI))
1789  return I;
1790 
1791  // See if we can fold the select into one of our operands.
1792  if (SelType->isIntOrIntVectorTy() || SelType->isFPOrFPVectorTy()) {
1793  if (Instruction *FoldI = foldSelectIntoOp(SI, TrueVal, FalseVal))
1794  return FoldI;
1795 
1796  Value *LHS, *RHS;
1797  Instruction::CastOps CastOp;
1798  SelectPatternResult SPR = matchSelectPattern(&SI, LHS, RHS, &CastOp);
1799  auto SPF = SPR.Flavor;
1800  if (SPF) {
1801  Value *LHS2, *RHS2;
1802  if (SelectPatternFlavor SPF2 = matchSelectPattern(LHS, LHS2, RHS2).Flavor)
1803  if (Instruction *R = foldSPFofSPF(cast<Instruction>(LHS), SPF2, LHS2,
1804  RHS2, SI, SPF, RHS))
1805  return R;
1806  if (SelectPatternFlavor SPF2 = matchSelectPattern(RHS, LHS2, RHS2).Flavor)
1807  if (Instruction *R = foldSPFofSPF(cast<Instruction>(RHS), SPF2, LHS2,
1808  RHS2, SI, SPF, LHS))
1809  return R;
1810  // TODO.
1811  // ABS(-X) -> ABS(X)
1812  }
1813 
1815  // Canonicalize so that
1816  // - type casts are outside select patterns.
1817  // - float clamp is transformed to min/max pattern
1818 
1819  bool IsCastNeeded = LHS->getType() != SelType;
1820  Value *CmpLHS = cast<CmpInst>(CondVal)->getOperand(0);
1821  Value *CmpRHS = cast<CmpInst>(CondVal)->getOperand(1);
1822  if (IsCastNeeded ||
1823  (LHS->getType()->isFPOrFPVectorTy() &&
1824  ((CmpLHS != LHS && CmpLHS != RHS) ||
1825  (CmpRHS != LHS && CmpRHS != RHS)))) {
1826  CmpInst::Predicate Pred = getMinMaxPred(SPF, SPR.Ordered);
1827 
1828  Value *Cmp;
1829  if (CmpInst::isIntPredicate(Pred)) {
1830  Cmp = Builder.CreateICmp(Pred, LHS, RHS);
1831  } else {
1832  IRBuilder<>::FastMathFlagGuard FMFG(Builder);
1833  auto FMF = cast<FPMathOperator>(SI.getCondition())->getFastMathFlags();
1834  Builder.setFastMathFlags(FMF);
1835  Cmp = Builder.CreateFCmp(Pred, LHS, RHS);
1836  }
1837 
1838  Value *NewSI = Builder.CreateSelect(Cmp, LHS, RHS, SI.getName(), &SI);
1839  if (!IsCastNeeded)
1840  return replaceInstUsesWith(SI, NewSI);
1841 
1842  Value *NewCast = Builder.CreateCast(CastOp, NewSI, SelType);
1843  return replaceInstUsesWith(SI, NewCast);
1844  }
1845 
1846  // MAX(~a, ~b) -> ~MIN(a, b)
1847  // MAX(~a, C) -> ~MIN(a, ~C)
1848  // MIN(~a, ~b) -> ~MAX(a, b)
1849  // MIN(~a, C) -> ~MAX(a, ~C)
1850  auto moveNotAfterMinMax = [&](Value *X, Value *Y,
1851  bool Swapped) -> Instruction * {
1852  Value *A;
1853  if (match(X, m_Not(m_Value(A))) && !X->hasNUsesOrMore(3) &&
1854  !IsFreeToInvert(A, A->hasOneUse()) &&
1855  // Passing false to only consider m_Not and constants.
1856  IsFreeToInvert(Y, false)) {
1857  Value *B = Builder.CreateNot(Y);
1858  Value *NewMinMax = createMinMax(Builder, getInverseMinMaxFlavor(SPF),
1859  A, B);
1860  // Copy the profile metadata.
1861  if (MDNode *MD = SI.getMetadata(LLVMContext::MD_prof)) {
1862  cast<SelectInst>(NewMinMax)->setMetadata(LLVMContext::MD_prof, MD);
1863  // Swap the metadata if the operands are swapped.
1864  if (Swapped) {
1865  assert(X == SI.getFalseValue() && Y == SI.getTrueValue() &&
1866  "Unexpected operands.");
1867  cast<SelectInst>(NewMinMax)->swapProfMetadata();
1868  } else {
1869  assert(X == SI.getTrueValue() && Y == SI.getFalseValue() &&
1870  "Unexpected operands.");
1871  }
1872  }
1873 
1874  return BinaryOperator::CreateNot(NewMinMax);
1875  }
1876 
1877  return nullptr;
1878  };
1879 
1880  if (Instruction *I = moveNotAfterMinMax(LHS, RHS, /*Swapped*/false))
1881  return I;
1882  if (Instruction *I = moveNotAfterMinMax(RHS, LHS, /*Swapped*/true))
1883  return I;
1884 
1885  if (Instruction *I = factorizeMinMaxTree(SPF, LHS, RHS, Builder))
1886  return I;
1887  }
1888  }
1889 
1890  // See if we can fold the select into a phi node if the condition is a select.
1891  if (auto *PN = dyn_cast<PHINode>(SI.getCondition()))
1892  // The true/false values have to be live in the PHI predecessor's blocks.
1893  if (canSelectOperandBeMappingIntoPredBlock(TrueVal, SI) &&
1894  canSelectOperandBeMappingIntoPredBlock(FalseVal, SI))
1895  if (Instruction *NV = foldOpIntoPhi(SI, PN))
1896  return NV;
1897 
1898  if (SelectInst *TrueSI = dyn_cast<SelectInst>(TrueVal)) {
1899  if (TrueSI->getCondition()->getType() == CondVal->getType()) {
1900  // select(C, select(C, a, b), c) -> select(C, a, c)
1901  if (TrueSI->getCondition() == CondVal) {
1902  if (SI.getTrueValue() == TrueSI->getTrueValue())
1903  return nullptr;
1904  SI.setOperand(1, TrueSI->getTrueValue());
1905  return &SI;
1906  }
1907  // select(C0, select(C1, a, b), b) -> select(C0&C1, a, b)
1908  // We choose this as normal form to enable folding on the And and shortening
1909  // paths for the values (this helps GetUnderlyingObjects() for example).
1910  if (TrueSI->getFalseValue() == FalseVal && TrueSI->hasOneUse()) {
1911  Value *And = Builder.CreateAnd(CondVal, TrueSI->getCondition());
1912  SI.setOperand(0, And);
1913  SI.setOperand(1, TrueSI->getTrueValue());
1914  return &SI;
1915  }
1916  }
1917  }
1918  if (SelectInst *FalseSI = dyn_cast<SelectInst>(FalseVal)) {
1919  if (FalseSI->getCondition()->getType() == CondVal->getType()) {
1920  // select(C, a, select(C, b, c)) -> select(C, a, c)
1921  if (FalseSI->getCondition() == CondVal) {
1922  if (SI.getFalseValue() == FalseSI->getFalseValue())
1923  return nullptr;
1924  SI.setOperand(2, FalseSI->getFalseValue());
1925  return &SI;
1926  }
1927  // select(C0, a, select(C1, a, b)) -> select(C0|C1, a, b)
1928  if (FalseSI->getTrueValue() == TrueVal && FalseSI->hasOneUse()) {
1929  Value *Or = Builder.CreateOr(CondVal, FalseSI->getCondition());
1930  SI.setOperand(0, Or);
1931  SI.setOperand(2, FalseSI->getFalseValue());
1932  return &SI;
1933  }
1934  }
1935  }
1936 
1937  auto canMergeSelectThroughBinop = [](BinaryOperator *BO) {
1938  // The select might be preventing a division by 0.
1939  switch (BO->getOpcode()) {
1940  default:
1941  return true;
1942  case Instruction::SRem:
1943  case Instruction::URem:
1944  case Instruction::SDiv:
1945  case Instruction::UDiv:
1946  return false;
1947  }
1948  };
1949 
1950  // Try to simplify a binop sandwiched between 2 selects with the same
1951  // condition.
1952  // select(C, binop(select(C, X, Y), W), Z) -> select(C, binop(X, W), Z)
1953  BinaryOperator *TrueBO;
1954  if (match(TrueVal, m_OneUse(m_BinOp(TrueBO))) &&
1955  canMergeSelectThroughBinop(TrueBO)) {
1956  if (auto *TrueBOSI = dyn_cast<SelectInst>(TrueBO->getOperand(0))) {
1957  if (TrueBOSI->getCondition() == CondVal) {
1958  TrueBO->setOperand(0, TrueBOSI->getTrueValue());
1959  Worklist.Add(TrueBO);
1960  return &SI;
1961  }
1962  }
1963  if (auto *TrueBOSI = dyn_cast<SelectInst>(TrueBO->getOperand(1))) {
1964  if (TrueBOSI->getCondition() == CondVal) {
1965  TrueBO->setOperand(1, TrueBOSI->getTrueValue());
1966  Worklist.Add(TrueBO);
1967  return &SI;
1968  }
1969  }
1970  }
1971 
1972  // select(C, Z, binop(select(C, X, Y), W)) -> select(C, Z, binop(Y, W))
1973  BinaryOperator *FalseBO;
1974  if (match(FalseVal, m_OneUse(m_BinOp(FalseBO))) &&
1975  canMergeSelectThroughBinop(FalseBO)) {
1976  if (auto *FalseBOSI = dyn_cast<SelectInst>(FalseBO->getOperand(0))) {
1977  if (FalseBOSI->getCondition() == CondVal) {
1978  FalseBO->setOperand(0, FalseBOSI->getFalseValue());
1979  Worklist.Add(FalseBO);
1980  return &SI;
1981  }
1982  }
1983  if (auto *FalseBOSI = dyn_cast<SelectInst>(FalseBO->getOperand(1))) {
1984  if (FalseBOSI->getCondition() == CondVal) {
1985  FalseBO->setOperand(1, FalseBOSI->getFalseValue());
1986  Worklist.Add(FalseBO);
1987  return &SI;
1988  }
1989  }
1990  }
1991 
1992  if (BinaryOperator::isNot(CondVal)) {
1994  SI.setOperand(1, FalseVal);
1995  SI.setOperand(2, TrueVal);
1996  return &SI;
1997  }
1998 
1999  if (VectorType *VecTy = dyn_cast<VectorType>(SelType)) {
2000  unsigned VWidth = VecTy->getNumElements();
2001  APInt UndefElts(VWidth, 0);
2002  APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
2003  if (Value *V = SimplifyDemandedVectorElts(&SI, AllOnesEltMask, UndefElts)) {
2004  if (V != &SI)
2005  return replaceInstUsesWith(SI, V);
2006  return &SI;
2007  }
2008  }
2009 
2010  // See if we can determine the result of this select based on a dominating
2011  // condition.
2012  BasicBlock *Parent = SI.getParent();
2013  if (BasicBlock *Dom = Parent->getSinglePredecessor()) {
2014  auto *PBI = dyn_cast_or_null<BranchInst>(Dom->getTerminator());
2015  if (PBI && PBI->isConditional() &&
2016  PBI->getSuccessor(0) != PBI->getSuccessor(1) &&
2017  (PBI->getSuccessor(0) == Parent || PBI->getSuccessor(1) == Parent)) {
2018  bool CondIsTrue = PBI->getSuccessor(0) == Parent;
2019  Optional<bool> Implication = isImpliedCondition(
2020  PBI->getCondition(), SI.getCondition(), DL, CondIsTrue);
2021  if (Implication) {
2022  Value *V = *Implication ? TrueVal : FalseVal;
2023  return replaceInstUsesWith(SI, V);
2024  }
2025  }
2026  }
2027 
2028  // If we can compute the condition, there's no need for a select.
2029  // Like the above fold, we are attempting to reduce compile-time cost by
2030  // putting this fold here with limitations rather than in InstSimplify.
2031  // The motivation for this call into value tracking is to take advantage of
2032  // the assumption cache, so make sure that is populated.
2033  if (!CondVal->getType()->isVectorTy() && !AC.assumptions().empty()) {
2034  KnownBits Known(1);
2035  computeKnownBits(CondVal, Known, 0, &SI);
2036  if (Known.One.isOneValue())
2037  return replaceInstUsesWith(SI, TrueVal);
2038  if (Known.Zero.isOneValue())
2039  return replaceInstUsesWith(SI, FalseVal);
2040  }
2041 
2042  if (Instruction *BitCastSel = foldSelectCmpBitcasts(SI, Builder))
2043  return BitCastSel;
2044 
2045  // Simplify selects that test the returned flag of cmpxchg instructions.
2046  if (Instruction *Select = foldSelectCmpXchg(SI))
2047  return Select;
2048 
2049  if (Instruction *Select = foldSelectBinOpIdentity(SI, TLI))
2050  return Select;
2051 
2052  return nullptr;
2053 }
MaxMin_match< ICmpInst, LHS, RHS, umin_pred_ty > m_UMin(const LHS &L, const RHS &R)
BinaryOp_match< LHS, RHS, Instruction::And > m_And(const LHS &L, const RHS &R)
Definition: PatternMatch.h:718
uint64_t CallInst * C
void computeKnownBits(const Value *V, KnownBits &Known, const DataLayout &DL, unsigned Depth=0, AssumptionCache *AC=nullptr, const Instruction *CxtI=nullptr, const DominatorTree *DT=nullptr, OptimizationRemarkEmitter *ORE=nullptr, bool UseInstrInfo=true)
Determine which bits of V are known to be either zero or one and return them in the KnownZero/KnownOn...
BinaryOp_match< cstfp_pred_ty< is_neg_zero_fp >, RHS, Instruction::FSub > m_FNeg(const RHS &X)
Match &#39;fneg X&#39; as &#39;fsub -0.0, X&#39;.
Definition: PatternMatch.h:665
static bool isSelect01(const APInt &C1I, const APInt &C2I)
static ConstantInt * getFalse(LLVMContext &Context)
Definition: Constants.cpp:584
static Instruction * foldSelectBinOpIdentity(SelectInst &Sel, const TargetLibraryInfo &TLI)
Replace a select operand based on an equality comparison with the identity constant of a binop...
class_match< Value > m_Value()
Match an arbitrary value and ignore it.
Definition: PatternMatch.h:72
Value * CreateICmp(CmpInst::Predicate P, Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1846
This class is the base class for the comparison instructions.
Definition: InstrTypes.h:675
static GCMetadataPrinterRegistry::Add< ErlangGCPrinter > X("erlang", "erlang-compatible garbage collector")
void setFastMathFlags(FastMathFlags FMF)
Convenience function for setting multiple fast-math flags on this instruction, which must be an opera...
bool isZero() const
Definition: APFloat.h:1143
static bool IsFreeToInvert(Value *V, bool WillInvertAllUses)
Return true if the specified value is free to invert (apply ~ to).
bool hasNoSignedZeros() const
Determine whether the no-signed-zeros flag is set.
class_match< CmpInst > m_Cmp()
Matches any compare instruction and ignore it.
Definition: PatternMatch.h:80
This instruction extracts a struct member or array element value from an aggregate value...
static APInt getAllOnesValue(unsigned numBits)
Get the all-ones value.
Definition: APInt.h:562
BinaryOp_match< LHS, RHS, Instruction::Sub > m_Sub(const LHS &L, const RHS &R)
Definition: PatternMatch.h:651
is_zero m_Zero()
Match any null constant or a vector with all elements equal to 0.
Definition: PatternMatch.h:373
DiagnosticInfoOptimizationBase::Argument NV
static BinaryOperator * CreateNot(Value *Op, const Twine &Name="", Instruction *InsertBefore=nullptr)
Value * CreateIsNotNull(Value *Arg, const Twine &Name="")
Return an i1 value testing if Arg is not null.
Definition: IRBuilder.h:1996
Unsigned minimum.
Value * CreateZExtOrTrunc(Value *V, Type *DestTy, const Twine &Name="")
Create a ZExt or Trunc from the integer value V to DestTy.
Definition: IRBuilder.h:1566
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
BinaryOps getOpcode() const
Definition: InstrTypes.h:355
Value * CreateXor(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1148
bool decomposeBitTestICmp(Value *LHS, Value *RHS, CmpInst::Predicate &Pred, Value *&X, APInt &Mask, bool LookThroughTrunc=true)
Decompose an icmp into the form ((X & Mask) pred 0) if possible.
an instruction that atomically checks whether a specified value is in a memory location, and, if it is, stores a new value there.
Definition: Instructions.h:518
This class represents zero extension of integer types.
static GetElementPtrInst * Create(Type *PointeeType, Value *Ptr, ArrayRef< Value *> IdxList, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
Definition: Instructions.h:867
bool slt(const APInt &RHS) const
Signed less than comparison.
Definition: APInt.h:1198
class_match< Constant > m_Constant()
Match an arbitrary Constant and ignore it.
Definition: PatternMatch.h:91
static bool isCanonicalPredicate(CmpInst::Predicate Pred)
Predicate canonicalization reduces the number of patterns that need to be matched by other transforms...
const Value * getTrueValue() const
unsigned less or equal
Definition: InstrTypes.h:711
unsigned less than
Definition: InstrTypes.h:710
0 1 0 0 True if ordered and less than
Definition: InstrTypes.h:691
This instruction constructs a fixed permutation of two input vectors.
static SelectInst * Create(Value *C, Value *S1, Value *S2, const Twine &NameStr="", Instruction *InsertBefore=nullptr, Instruction *MDFrom=nullptr)
LLVMContext & getContext() const
All values hold a context through their type.
Definition: Value.cpp:714
static unsigned getSelectFoldableOperands(BinaryOperator *I)
We want to turn code that looks like this: C = or A, B D = select cond, C, A into: C = select cond...
1 1 1 0 True if unordered or not equal
Definition: InstrTypes.h:701
static CastInst * CreateBitOrPointerCast(Value *S, Type *Ty, const Twine &Name="", Instruction *InsertBefore=nullptr)
Create a BitCast, a PtrToInt, or an IntToPTr cast instruction.
bool sgt(const APInt &RHS) const
Signed greather than comparison.
Definition: APInt.h:1268
static bool isEquality(Predicate P)
Return true if this predicate is either EQ or NE.
Metadata node.
Definition: Metadata.h:864
SelectPatternFlavor getInverseMinMaxFlavor(SelectPatternFlavor SPF)
Return the inverse minimum/maximum flavor of the specified flavor.
This class represents a sign extension of integer types.
BinaryOp_match< LHS, RHS, Instruction::FSub > m_FSub(const LHS &L, const RHS &R)
Definition: PatternMatch.h:657
bool isVectorTy() const
True if this is an instance of VectorType.
Definition: Type.h:230
void reserve(size_type N)
Definition: SmallVector.h:376
bool sle(const APInt &RHS) const
Signed less or equal comparison.
Definition: APInt.h:1233
void copyIRFlags(const Value *V, bool IncludeWrapFlags=true)
Convenience method to copy supported exact, fast-math, and (optionally) wrapping flags from V to this...
AnyBinaryOp_match< LHS, RHS, true > m_c_BinOp(const LHS &L, const RHS &R)
Matches a BinaryOperator with LHS and RHS in either order.
cst_pred_ty< is_zero_int > m_ZeroInt()
Match an integer 0 or a vector with all elements equal to 0.
Definition: PatternMatch.h:361
bool Ordered
Only applicable if Flavor is SPF_FMINNUM or SPF_FMAXNUM.
unsigned getBitWidth() const
Return the number of bits in the APInt.
Definition: APInt.h:1503
Signed maximum.
static Constant * getNullValue(Type *Ty)
Constructor to create a &#39;0&#39; constant of arbitrary type.
Definition: Constants.cpp:268
Value * CreateNot(Value *V, const Twine &Name="")
Definition: IRBuilder.h:1282
static GCMetadataPrinterRegistry::Add< OcamlGCMetadataPrinter > Y("ocaml", "ocaml 3.10-compatible collector")
bool match(Val *V, const Pattern &P)
Definition: PatternMatch.h:49
static Value * foldSelectICmpAnd(SelectInst &Sel, ICmpInst *Cmp, InstCombiner::BuilderTy &Builder)
This folds: select (icmp eq (and X, C1)), TC, FC iff C1 is a power 2 and the difference between TC an...
BinaryOp_match< LHS, RHS, Instruction::Xor > m_Xor(const LHS &L, const RHS &R)
Definition: PatternMatch.h:730
This class represents the LLVM &#39;select&#39; instruction.
Predicate getInversePredicate() const
For example, EQ -> NE, UGT -> ULE, SLT -> SGE, OEQ -> UNE, UGT -> OLE, OLT -> UGE, etc.
Definition: InstrTypes.h:783
Absolute value.
bool isUnsigned() const
Definition: InstrTypes.h:860
CastClass_match< OpTy, Instruction::Trunc > m_Trunc(const OpTy &Op)
Matches Trunc.
This provides a uniform API for creating instructions and inserting them into a basic block: either a...
Definition: IRBuilder.h:731
0 1 0 1 True if ordered and less than or equal
Definition: InstrTypes.h:692
static Constant * getSExt(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1628
This file implements a class to represent arbitrary precision integral constant values and operations...
static Constant * getZExt(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1642
Instruction * clone() const
Create a copy of &#39;this&#39; instruction that is identical in all ways except the following: ...
bool isNullValue() const
Return true if this is the value that would be returned by getNullValue.
Definition: Constants.cpp:85
FastMathFlags getFastMathFlags() const
Convenience function for getting all the fast-math flags, which must be an operator which supports th...
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:245
CastClass_match< OpTy, Instruction::ZExt > m_ZExt(const OpTy &Op)
Matches ZExt.
This instruction compares its operands according to the predicate given to the constructor.
void andIRFlags(const Value *V)
Logical &#39;and&#39; of any supported wrapping, exact, and fast-math flags of V and this instruction...
MaxMin_match< ICmpInst, LHS, RHS, smin_pred_ty > m_SMin(const LHS &L, const RHS &R)
MDNode * getMetadata(unsigned KindID) const
Get the metadata of given kind attached to this Instruction.
Definition: Instruction.h:217
unsigned getOpcode() const
Returns a member of one of the enums like Instruction::Add.
Definition: Instruction.h:126
cstfp_pred_ty< is_pos_zero_fp > m_PosZeroFP()
Match a floating-point positive zero.
Definition: PatternMatch.h:442
Value * CreateSub(Value *LHS, Value *RHS, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:979
bool isIntOrIntVectorTy() const
Return true if this is an integer type or a vector of integer types.
Definition: Type.h:203
static Instruction * foldSelectICmpAndAnd(Type *SelType, const ICmpInst *Cmp, Value *TVal, Value *FVal, InstCombiner::BuilderTy &Builder)
We want to turn: (select (icmp eq (and X, Y), 0), (and (lshr X, Z), 1), 1) into: zext (icmp ne i32 (a...
cst_pred_ty< is_power2 > m_Power2()
Match an integer or vector power-of-2.
Definition: PatternMatch.h:382
void takeName(Value *V)
Transfer the name from V to this value.
Definition: Value.cpp:301
static BinaryOperator * CreateAdd(Value *S1, Value *S2, const Twine &Name, Instruction *InsertBefore, Value *FlagsOp)
static const Value * getNotArgument(const Value *BinOp)
Value * getOperand(unsigned i) const
Definition: User.h:170
bool CannotBeNegativeZero(const Value *V, const TargetLibraryInfo *TLI, unsigned Depth=0)
Return true if we can prove that the specified FP value is never equal to -0.0.
void replaceUsesOfWith(Value *From, Value *To)
Replace uses of one Value with another.
Definition: User.cpp:21
Value * CreateOr(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1130
Constant * getAggregateElement(unsigned Elt) const
For aggregates (struct/array/vector) return the constant that corresponds to the specified element if...
Definition: Constants.cpp:338
Type * getScalarType() const
If this is a vector type, return the element type, otherwise return &#39;this&#39;.
Definition: Type.h:304
Value * CreateFCmp(CmpInst::Predicate P, Value *LHS, Value *RHS, const Twine &Name="", MDNode *FPMathTag=nullptr)
Definition: IRBuilder.h:1854
OneUse_match< T > m_OneUse(const T &SubPattern)
Definition: PatternMatch.h:63
#define P(N)
BinaryOp_match< LHS, RHS, Instruction::LShr > m_LShr(const LHS &L, const RHS &R)
Definition: PatternMatch.h:742
bool hasNUsesOrMore(unsigned N) const
Return true if this value has N users or more.
Definition: Value.cpp:140
Value * SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal, const SimplifyQuery &Q)
Given operands for a SelectInst, fold the result or return null.
bool isAllOnesValue() const
Determine if all bits are set.
Definition: APInt.h:396
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
MaxMin_match< ICmpInst, LHS, RHS, umax_pred_ty > m_UMax(const LHS &L, const RHS &R)
bool hasNUses(unsigned N) const
Return true if this Value has exactly N users.
Definition: Value.cpp:132
apint_match m_APInt(const APInt *&Res)
Match a ConstantInt or splatted ConstantVector, binding the specified pointer to the contained APInt...
Definition: PatternMatch.h:177
const BasicBlock * getSinglePredecessor() const
Return the predecessor of this block if it has a single predecessor block.
Definition: BasicBlock.cpp:235
bool isKnownNegation(const Value *X, const Value *Y, bool NeedNSW=false)
Return true if the two given values are negation.
LLVM Basic Block Representation.
Definition: BasicBlock.h:59
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:46
BinaryOp_match< LHS, RHS, Instruction::Or > m_Or(const LHS &L, const RHS &R)
Definition: PatternMatch.h:724
CallInst * CreateIntrinsic(Intrinsic::ID ID, Instruction *FMFSource=nullptr, const Twine &Name="")
Create a call to intrinsic ID with no operands.
Definition: IRBuilder.cpp:742
bool ult(const APInt &RHS) const
Unsigned less than comparison.
Definition: APInt.h:1179
CastClass_match< OpTy, Instruction::BitCast > m_BitCast(const OpTy &Op)
Matches BitCast.
This is an important base class in LLVM.
Definition: Constant.h:42
This file contains the declarations for the subclasses of Constant, which represent the different fla...
Value * CreateSelect(Value *C, Value *True, Value *False, const Twine &Name="", Instruction *MDFrom=nullptr)
Definition: IRBuilder.h:1901
BinaryOp_match< LHS, RHS, Instruction::And, true > m_c_And(const LHS &L, const RHS &R)
Matches an And with LHS and RHS in either order.
ConstantFP - Floating Point Values [float, double].
Definition: Constants.h:264
bool isOneValue() const
Determine if this is a value of 1.
Definition: APInt.h:411
cst_pred_ty< is_all_ones > m_AllOnes()
Match an integer or vector with all bits set.
Definition: PatternMatch.h:306
static APInt getOneBitSet(unsigned numBits, unsigned BitNo)
Return an APInt with exactly one bit set in the result.
Definition: APInt.h:588
specificval_ty m_Specific(const Value *V)
Match if we have a specific specified value.
Definition: PatternMatch.h:499
bool any_of(R &&Range, UnaryPredicate P)
Provide wrappers to std::any_of which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:1049
Value * CreateNeg(Value *V, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:1256
This instruction compares its operands according to the predicate given to the constructor.
Predicate
This enumeration lists the possible predicates for CmpInst subclasses.
Definition: InstrTypes.h:685
static Constant * getBinOpIdentity(unsigned Opcode, Type *Ty, bool AllowRHSConstant=false)
Return the identity constant for a binary opcode.
Definition: Constants.cpp:2274
void setArgOperand(unsigned i, Value *v)
CmpInst::Predicate getMinMaxPred(SelectPatternFlavor SPF, bool Ordered=false)
Return the canonical comparison predicate for the specified minimum/maximum flavor.
static bool isNot(const Value *V)
class_match< BinaryOperator > m_BinOp()
Match an arbitrary binary operation and ignore it.
Definition: PatternMatch.h:75
Class to represent integer types.
Definition: DerivedTypes.h:40
const Value * getCondition() const
bool isCast() const
Definition: Instruction.h:133
C setMetadata(LLVMContext::MD_range, MDNode::get(Context, LowAndHigh))
void swapProfMetadata()
If the instruction has "branch_weights" MD_prof metadata and the MDNode has three operands (including...
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
signed greater than
Definition: InstrTypes.h:712
const APFloat & getValueAPF() const
Definition: Constants.h:299
CastClass_match< OpTy, Instruction::SExt > m_SExt(const OpTy &Op)
Matches SExt.
Floating point maxnum.
static Value * createMinMax(InstCombiner::BuilderTy &Builder, SelectPatternFlavor SPF, Value *A, Value *B)
0 0 1 0 True if ordered and greater than
Definition: InstrTypes.h:689
static Value * foldSelectICmpAndOr(const ICmpInst *IC, Value *TrueVal, Value *FalseVal, InstCombiner::BuilderTy &Builder)
We want to turn: (select (icmp eq (and X, C1), 0), Y, (or Y, C2)) into: (or (shl (and X...
unsigned getNumOperands() const
Definition: User.h:192
SelectPatternFlavor Flavor
unsigned getScalarSizeInBits() const LLVM_READONLY
If this is a vector type, return the getPrimitiveSizeInBits value for the element type...
Definition: Type.cpp:130
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:847
SelectPatternFlavor
Specific patterns of select instructions we can match.
Instruction * user_back()
Specialize the methods defined in Value, as we know that an instruction can only be used by other ins...
Definition: Instruction.h:64
Provides information about what library functions are available for the current target.
signed less than
Definition: InstrTypes.h:714
static GCRegistry::Add< StatepointGC > D("statepoint-example", "an example strategy for statepoint")
static Constant * getTrunc(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1614
static Constant * get(Type *Ty, uint64_t V, bool isSigned=false)
If Ty is a vector type, return a Constant with a splat of the given value.
Definition: Constants.cpp:621
bool uge(const APInt &RHS) const
Unsigned greater or equal comparison.
Definition: APInt.h:1287
static ConstantInt * getTrue(LLVMContext &Context)
Definition: Constants.cpp:577
bool isCommutative() const
Return true if the instruction is commutative:
Definition: Instruction.h:474
Instruction * visitSelectInst(SelectInst &SI)
void setPredicate(Predicate P)
Set the predicate for this instruction to the specified value.
Definition: InstrTypes.h:764
void setOperand(unsigned i, Value *Val)
Definition: User.h:175
unsigned logBase2() const
Definition: APInt.h:1742
BinaryOp_match< cst_pred_ty< is_zero_int >, ValTy, Instruction::Sub > m_Neg(const ValTy &V)
Matches a &#39;Neg&#39; as &#39;sub 0, V&#39;.
void swap(llvm::BitVector &LHS, llvm::BitVector &RHS)
Implement std::swap in terms of BitVector swap.
Definition: BitVector.h:941
unsigned getVectorNumElements() const
Definition: DerivedTypes.h:462
bool isIntPredicate() const
Definition: InstrTypes.h:777
Class to represent vector types.
Definition: DerivedTypes.h:393
Class for arbitrary precision integers.
Definition: APInt.h:70
bool ule(const APInt &RHS) const
Unsigned less or equal comparison.
Definition: APInt.h:1217
bool isPowerOf2() const
Check if this APInt&#39;s value is a power of two greater than zero.
Definition: APInt.h:464
static BinaryOperator * Create(BinaryOps Op, Value *S1, Value *S2, const Twine &Name=Twine(), Instruction *InsertBefore=nullptr)
Construct a binary instruction, given the opcode and the two operands.
bool sge(const APInt &RHS) const
Signed greater or equal comparison.
Definition: APInt.h:1303
iterator_range< user_iterator > users()
Definition: Value.h:400
static Constant * getCast(unsigned ops, Constant *C, Type *Ty, bool OnlyIfReduced=false)
Convenience function for getting a Cast operation.
Definition: Constants.cpp:1507
Value * CreateShl(Value *LHS, Value *RHS, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:1051
const Value * getFalseValue() const
void setCondition(Value *V)
static APInt getSelectFoldableConstant(BinaryOperator *I)
For the same transformation as the previous function, return the identity constant that goes into the...
static CastInst * Create(Instruction::CastOps, Value *S, Type *Ty, const Twine &Name="", Instruction *InsertBefore=nullptr)
Provides a way to construct any of the CastInst subclasses using an opcode instead of the subclass&#39;s ...
bool ugt(const APInt &RHS) const
Unsigned greather than comparison.
Definition: APInt.h:1249
Predicate getPredicate() const
Return the predicate for this instruction.
Definition: InstrTypes.h:759
static cl::opt< bool > NeedAnd("extract-needand", cl::init(true), cl::Hidden, cl::desc("Require & in extract patterns"))
static Value * canonicalizeSaturatedSubtract(const ICmpInst *ICI, const Value *TrueVal, const Value *FalseVal, InstCombiner::BuilderTy &Builder)
Transform patterns such as: (a > b) ? a - b : 0 into: ((a > b) ? a : b) - b) This produces a canonica...
void setTrueValue(Value *V)
static IntegerType * getInt32Ty(LLVMContext &C)
Definition: Type.cpp:176
static bool isMinOrMax(SelectPatternFlavor SPF)
When implementing this min/max pattern as fcmp; select, does the fcmp have to be ordered?
unsigned greater or equal
Definition: InstrTypes.h:709
static bool isUnordered(Predicate predicate)
Determine if the predicate is an unordered operation.
StringRef getName() const
Return a constant reference to the value&#39;s name.
Definition: Value.cpp:224
bool isEquality() const
Return true if this predicate is either EQ or NE.
#define I(x, y, z)
Definition: MD5.cpp:58
MaxMin_match< ICmpInst, LHS, RHS, smax_pred_ty > m_SMax(const LHS &L, const RHS &R)
LLVM_NODISCARD std::enable_if<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:323
void setFalseValue(Value *V)
Signed minimum.
Value * CreateAnd(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1112
Optional< bool > isImpliedCondition(const Value *LHS, const Value *RHS, const DataLayout &DL, bool LHSIsTrue=true, unsigned Depth=0)
Return true if RHS is known to be implied true by LHS.
InstTy * Insert(InstTy *I, const Twine &Name="") const
Insert and return the specified instruction.
Definition: IRBuilder.h:782
bool isFPOrFPVectorTy() const
Return true if this is a FP type or a vector of FP.
Definition: Type.h:185
bool isOneValue() const
Returns true if the value is one.
Definition: Constants.cpp:126
Value * CreateCast(Instruction::CastOps Op, Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1666
static GetElementPtrInst * CreateInBounds(Value *Ptr, ArrayRef< Value *> IdxList, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
Create an "inbounds" getelementptr.
Definition: Instructions.h:901
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
static APInt getSignedMinValue(unsigned numBits)
Gets minimum signed value of APInt for a specific bit width.
Definition: APInt.h:545
0 0 0 1 True if ordered and equal
Definition: InstrTypes.h:688
LLVM Value Representation.
Definition: Value.h:73
This file provides internal interfaces used to implement the InstCombine.
SelectPatternResult matchSelectPattern(Value *V, Value *&LHS, Value *&RHS, Instruction::CastOps *CastOp=nullptr, unsigned Depth=0)
Pattern match integer [SU]MIN, [SU]MAX and ABS idioms, returning the kind and providing the out param...
cst_pred_ty< is_one > m_One()
Match an integer 1 or a vector with all elements equal to 1.
Definition: PatternMatch.h:352
std::underlying_type< E >::type Mask()
Get a bitmask with 1s in all places up to the high-order bit of E&#39;s largest value.
Definition: BitmaskEnum.h:81
void setFastMathFlags(FastMathFlags NewFMF)
Set the fast-math flags to be used with generated fp-math operators.
Definition: IRBuilder.h:220
void moveBefore(Instruction *MovePos)
Unlink this instruction from its current basic block and insert it into the basic block that MovePos ...
Definition: Instruction.cpp:87
Value * CreateLShr(Value *LHS, Value *RHS, const Twine &Name="", bool isExact=false)
Definition: IRBuilder.h:1072
bool hasOneUse() const
Return true if there is exactly one user of this value.
Definition: Value.h:413
Convenience struct for specifying and reasoning about fast-math flags.
Definition: Operator.h:160
unsigned greater than
Definition: InstrTypes.h:708
Predicate getSwappedPredicate() const
For example, EQ->EQ, SLE->SGE, ULT->UGT, OEQ->OEQ, ULE->UGE, OLT->OGT, etc.
Definition: InstrTypes.h:799
static APInt getNullValue(unsigned numBits)
Get the &#39;0&#39; value.
Definition: APInt.h:569
specific_intval m_SpecificInt(uint64_t V)
Match a specific integer value or vector with all elements equal to the value.
Definition: PatternMatch.h:576
cstfp_pred_ty< is_any_zero_fp > m_AnyZeroFP()
Match a floating-point negative zero or positive zero.
Definition: PatternMatch.h:433
0 0 1 1 True if ordered and greater than or equal
Definition: InstrTypes.h:690
static Constant * get(ArrayRef< Constant *> V)
Definition: Constants.cpp:1056
Value * CreateFNeg(Value *V, const Twine &Name="", MDNode *FPMathTag=nullptr)
Definition: IRBuilder.h:1274
bind_ty< Instruction > m_Instruction(Instruction *&I)
Match an instruction, capturing it if we match.
Definition: PatternMatch.h:476
BinaryOp_match< ValTy, cst_pred_ty< is_all_ones >, Instruction::Xor, true > m_Not(const ValTy &V)
Matches a &#39;Not&#39; as &#39;xor V, -1&#39; or &#39;xor -1, V&#39;.
bool isNullValue() const
Determine if all bits are clear.
Definition: APInt.h:406
IntegerType * Int32Ty
A wrapper class for inspecting calls to intrinsic functions.
Definition: IntrinsicInst.h:44
const BasicBlock * getParent() const
Definition: Instruction.h:67
CmpClass_match< LHS, RHS, ICmpInst, ICmpInst::Predicate > m_ICmp(ICmpInst::Predicate &Pred, const LHS &L, const RHS &R)
Definition: PatternMatch.h:983