LLVM  4.0.0
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"
18 #include "llvm/IR/MDBuilder.h"
19 #include "llvm/IR/PatternMatch.h"
20 using namespace llvm;
21 using namespace PatternMatch;
22 
23 #define DEBUG_TYPE "instcombine"
24 
27  switch (SPF) {
28  default:
29  llvm_unreachable("unhandled!");
30 
31  case SPF_SMIN:
32  return SPF_SMAX;
33  case SPF_UMIN:
34  return SPF_UMAX;
35  case SPF_SMAX:
36  return SPF_SMIN;
37  case SPF_UMAX:
38  return SPF_UMIN;
39  }
40 }
41 
43  bool Ordered=false) {
44  switch (SPF) {
45  default:
46  llvm_unreachable("unhandled!");
47 
48  case SPF_SMIN:
49  return ICmpInst::ICMP_SLT;
50  case SPF_UMIN:
51  return ICmpInst::ICMP_ULT;
52  case SPF_SMAX:
53  return ICmpInst::ICMP_SGT;
54  case SPF_UMAX:
55  return ICmpInst::ICMP_UGT;
56  case SPF_FMINNUM:
57  return Ordered ? FCmpInst::FCMP_OLT : FCmpInst::FCMP_ULT;
58  case SPF_FMAXNUM:
59  return Ordered ? FCmpInst::FCMP_OGT : FCmpInst::FCMP_UGT;
60  }
61 }
62 
65  Value *B) {
68  return Builder->CreateSelect(Builder->CreateICmp(Pred, A, B), A, B);
69 }
70 
71 /// We want to turn code that looks like this:
72 /// %C = or %A, %B
73 /// %D = select %cond, %C, %A
74 /// into:
75 /// %C = select %cond, %B, 0
76 /// %D = or %A, %C
77 ///
78 /// Assuming that the specified instruction is an operand to the select, return
79 /// a bitmask indicating which operands of this instruction are foldable if they
80 /// equal the other incoming value of the select.
81 ///
83  switch (I->getOpcode()) {
84  case Instruction::Add:
85  case Instruction::Mul:
86  case Instruction::And:
87  case Instruction::Or:
88  case Instruction::Xor:
89  return 3; // Can fold through either operand.
90  case Instruction::Sub: // Can only fold on the amount subtracted.
91  case Instruction::Shl: // Can only fold on the shift amount.
92  case Instruction::LShr:
93  case Instruction::AShr:
94  return 1;
95  default:
96  return 0; // Cannot fold
97  }
98 }
99 
100 /// For the same transformation as the previous function, return the identity
101 /// constant that goes into the select.
103  switch (I->getOpcode()) {
104  default: llvm_unreachable("This cannot happen!");
105  case Instruction::Add:
106  case Instruction::Sub:
107  case Instruction::Or:
108  case Instruction::Xor:
109  case Instruction::Shl:
110  case Instruction::LShr:
111  case Instruction::AShr:
112  return Constant::getNullValue(I->getType());
113  case Instruction::And:
114  return Constant::getAllOnesValue(I->getType());
115  case Instruction::Mul:
116  return ConstantInt::get(I->getType(), 1);
117  }
118 }
119 
120 /// We have (select c, TI, FI), and we know that TI and FI have the same opcode.
121 Instruction *InstCombiner::foldSelectOpOp(SelectInst &SI, Instruction *TI,
122  Instruction *FI) {
123  // If this is a cast from the same type, merge.
124  if (TI->getNumOperands() == 1 && TI->isCast()) {
125  Type *FIOpndTy = FI->getOperand(0)->getType();
126  if (TI->getOperand(0)->getType() != FIOpndTy)
127  return nullptr;
128 
129  // The select condition may be a vector. We may only change the operand
130  // type if the vector width remains the same (and matches the condition).
131  Type *CondTy = SI.getCondition()->getType();
132  if (CondTy->isVectorTy()) {
133  if (!FIOpndTy->isVectorTy())
134  return nullptr;
135  if (CondTy->getVectorNumElements() != FIOpndTy->getVectorNumElements())
136  return nullptr;
137 
138  // TODO: If the backend knew how to deal with casts better, we could
139  // remove this limitation. For now, there's too much potential to create
140  // worse codegen by promoting the select ahead of size-altering casts
141  // (PR28160).
142  //
143  // Note that ValueTracking's matchSelectPattern() looks through casts
144  // without checking 'hasOneUse' when it matches min/max patterns, so this
145  // transform may end up happening anyway.
146  if (TI->getOpcode() != Instruction::BitCast &&
147  (!TI->hasOneUse() || !FI->hasOneUse()))
148  return nullptr;
149 
150  } else if (!TI->hasOneUse() || !FI->hasOneUse()) {
151  // TODO: The one-use restrictions for a scalar select could be eased if
152  // the fold of a select in visitLoadInst() was enhanced to match a pattern
153  // that includes a cast.
154  return nullptr;
155  }
156 
157  // Fold this by inserting a select from the input values.
158  Value *NewSI =
159  Builder->CreateSelect(SI.getCondition(), TI->getOperand(0),
160  FI->getOperand(0), SI.getName() + ".v", &SI);
161  return CastInst::Create(Instruction::CastOps(TI->getOpcode()), NewSI,
162  TI->getType());
163  }
164 
165  // Only handle binary operators with one-use here. As with the cast case
166  // above, it may be possible to relax the one-use constraint, but that needs
167  // be examined carefully since it may not reduce the total number of
168  // instructions.
170  if (!BO || !TI->hasOneUse() || !FI->hasOneUse())
171  return nullptr;
172 
173  // Figure out if the operations have any operands in common.
174  Value *MatchOp, *OtherOpT, *OtherOpF;
175  bool MatchIsOpZero;
176  if (TI->getOperand(0) == FI->getOperand(0)) {
177  MatchOp = TI->getOperand(0);
178  OtherOpT = TI->getOperand(1);
179  OtherOpF = FI->getOperand(1);
180  MatchIsOpZero = true;
181  } else if (TI->getOperand(1) == FI->getOperand(1)) {
182  MatchOp = TI->getOperand(1);
183  OtherOpT = TI->getOperand(0);
184  OtherOpF = FI->getOperand(0);
185  MatchIsOpZero = false;
186  } else if (!TI->isCommutative()) {
187  return nullptr;
188  } else if (TI->getOperand(0) == FI->getOperand(1)) {
189  MatchOp = TI->getOperand(0);
190  OtherOpT = TI->getOperand(1);
191  OtherOpF = FI->getOperand(0);
192  MatchIsOpZero = true;
193  } else if (TI->getOperand(1) == FI->getOperand(0)) {
194  MatchOp = TI->getOperand(1);
195  OtherOpT = TI->getOperand(0);
196  OtherOpF = FI->getOperand(1);
197  MatchIsOpZero = true;
198  } else {
199  return nullptr;
200  }
201 
202  // If we reach here, they do have operations in common.
203  Value *NewSI = Builder->CreateSelect(SI.getCondition(), OtherOpT, OtherOpF,
204  SI.getName() + ".v", &SI);
205  Value *Op0 = MatchIsOpZero ? MatchOp : NewSI;
206  Value *Op1 = MatchIsOpZero ? NewSI : MatchOp;
207  return BinaryOperator::Create(BO->getOpcode(), Op0, Op1);
208 }
209 
210 static bool isSelect01(Constant *C1, Constant *C2) {
211  ConstantInt *C1I = dyn_cast<ConstantInt>(C1);
212  if (!C1I)
213  return false;
214  ConstantInt *C2I = dyn_cast<ConstantInt>(C2);
215  if (!C2I)
216  return false;
217  if (!C1I->isZero() && !C2I->isZero()) // One side must be zero.
218  return false;
219  return C1I->isOne() || C1I->isAllOnesValue() ||
220  C2I->isOne() || C2I->isAllOnesValue();
221 }
222 
223 /// Try to fold the select into one of the operands to allow further
224 /// optimization.
225 Instruction *InstCombiner::foldSelectIntoOp(SelectInst &SI, Value *TrueVal,
226  Value *FalseVal) {
227  // See the comment above GetSelectFoldableOperands for a description of the
228  // transformation we are doing here.
229  if (Instruction *TVI = dyn_cast<Instruction>(TrueVal)) {
230  if (TVI->hasOneUse() && TVI->getNumOperands() == 2 &&
231  !isa<Constant>(FalseVal)) {
232  if (unsigned SFO = getSelectFoldableOperands(TVI)) {
233  unsigned OpToFold = 0;
234  if ((SFO & 1) && FalseVal == TVI->getOperand(0)) {
235  OpToFold = 1;
236  } else if ((SFO & 2) && FalseVal == TVI->getOperand(1)) {
237  OpToFold = 2;
238  }
239 
240  if (OpToFold) {
242  Value *OOp = TVI->getOperand(2-OpToFold);
243  // Avoid creating select between 2 constants unless it's selecting
244  // between 0, 1 and -1.
245  if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) {
246  Value *NewSel = Builder->CreateSelect(SI.getCondition(), OOp, C);
247  NewSel->takeName(TVI);
248  BinaryOperator *TVI_BO = cast<BinaryOperator>(TVI);
250  FalseVal, NewSel);
251  BO->copyIRFlags(TVI_BO);
252  return BO;
253  }
254  }
255  }
256  }
257  }
258 
259  if (Instruction *FVI = dyn_cast<Instruction>(FalseVal)) {
260  if (FVI->hasOneUse() && FVI->getNumOperands() == 2 &&
261  !isa<Constant>(TrueVal)) {
262  if (unsigned SFO = getSelectFoldableOperands(FVI)) {
263  unsigned OpToFold = 0;
264  if ((SFO & 1) && TrueVal == FVI->getOperand(0)) {
265  OpToFold = 1;
266  } else if ((SFO & 2) && TrueVal == FVI->getOperand(1)) {
267  OpToFold = 2;
268  }
269 
270  if (OpToFold) {
272  Value *OOp = FVI->getOperand(2-OpToFold);
273  // Avoid creating select between 2 constants unless it's selecting
274  // between 0, 1 and -1.
275  if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) {
276  Value *NewSel = Builder->CreateSelect(SI.getCondition(), C, OOp);
277  NewSel->takeName(FVI);
278  BinaryOperator *FVI_BO = cast<BinaryOperator>(FVI);
280  TrueVal, NewSel);
281  BO->copyIRFlags(FVI_BO);
282  return BO;
283  }
284  }
285  }
286  }
287  }
288 
289  return nullptr;
290 }
291 
292 /// We want to turn:
293 /// (select (icmp eq (and X, C1), 0), Y, (or Y, C2))
294 /// into:
295 /// (or (shl (and X, C1), C3), y)
296 /// iff:
297 /// C1 and C2 are both powers of 2
298 /// where:
299 /// C3 = Log(C2) - Log(C1)
300 ///
301 /// This transform handles cases where:
302 /// 1. The icmp predicate is inverted
303 /// 2. The select operands are reversed
304 /// 3. The magnitude of C2 and C1 are flipped
305 static Value *foldSelectICmpAndOr(const SelectInst &SI, Value *TrueVal,
306  Value *FalseVal,
307  InstCombiner::BuilderTy *Builder) {
308  const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition());
309  if (!IC || !IC->isEquality() || !SI.getType()->isIntegerTy())
310  return nullptr;
311 
312  Value *CmpLHS = IC->getOperand(0);
313  Value *CmpRHS = IC->getOperand(1);
314 
315  if (!match(CmpRHS, m_Zero()))
316  return nullptr;
317 
318  Value *X;
319  const APInt *C1;
320  if (!match(CmpLHS, m_And(m_Value(X), m_Power2(C1))))
321  return nullptr;
322 
323  const APInt *C2;
324  bool OrOnTrueVal = false;
325  bool OrOnFalseVal = match(FalseVal, m_Or(m_Specific(TrueVal), m_Power2(C2)));
326  if (!OrOnFalseVal)
327  OrOnTrueVal = match(TrueVal, m_Or(m_Specific(FalseVal), m_Power2(C2)));
328 
329  if (!OrOnFalseVal && !OrOnTrueVal)
330  return nullptr;
331 
332  Value *V = CmpLHS;
333  Value *Y = OrOnFalseVal ? TrueVal : FalseVal;
334 
335  unsigned C1Log = C1->logBase2();
336  unsigned C2Log = C2->logBase2();
337  if (C2Log > C1Log) {
338  V = Builder->CreateZExtOrTrunc(V, Y->getType());
339  V = Builder->CreateShl(V, C2Log - C1Log);
340  } else if (C1Log > C2Log) {
341  V = Builder->CreateLShr(V, C1Log - C2Log);
342  V = Builder->CreateZExtOrTrunc(V, Y->getType());
343  } else
344  V = Builder->CreateZExtOrTrunc(V, Y->getType());
345 
346  ICmpInst::Predicate Pred = IC->getPredicate();
347  if ((Pred == ICmpInst::ICMP_NE && OrOnFalseVal) ||
348  (Pred == ICmpInst::ICMP_EQ && OrOnTrueVal))
349  V = Builder->CreateXor(V, *C2);
350 
351  return Builder->CreateOr(V, Y);
352 }
353 
354 /// Attempt to fold a cttz/ctlz followed by a icmp plus select into a single
355 /// call to cttz/ctlz with flag 'is_zero_undef' cleared.
356 ///
357 /// For example, we can fold the following code sequence:
358 /// \code
359 /// %0 = tail call i32 @llvm.cttz.i32(i32 %x, i1 true)
360 /// %1 = icmp ne i32 %x, 0
361 /// %2 = select i1 %1, i32 %0, i32 32
362 /// \code
363 ///
364 /// into:
365 /// %0 = tail call i32 @llvm.cttz.i32(i32 %x, i1 false)
366 static Value *foldSelectCttzCtlz(ICmpInst *ICI, Value *TrueVal, Value *FalseVal,
367  InstCombiner::BuilderTy *Builder) {
368  ICmpInst::Predicate Pred = ICI->getPredicate();
369  Value *CmpLHS = ICI->getOperand(0);
370  Value *CmpRHS = ICI->getOperand(1);
371 
372  // Check if the condition value compares a value for equality against zero.
373  if (!ICI->isEquality() || !match(CmpRHS, m_Zero()))
374  return nullptr;
375 
376  Value *Count = FalseVal;
377  Value *ValueOnZero = TrueVal;
378  if (Pred == ICmpInst::ICMP_NE)
379  std::swap(Count, ValueOnZero);
380 
381  // Skip zero extend/truncate.
382  Value *V = nullptr;
383  if (match(Count, m_ZExt(m_Value(V))) ||
384  match(Count, m_Trunc(m_Value(V))))
385  Count = V;
386 
387  // Check if the value propagated on zero is a constant number equal to the
388  // sizeof in bits of 'Count'.
389  unsigned SizeOfInBits = Count->getType()->getScalarSizeInBits();
390  if (!match(ValueOnZero, m_SpecificInt(SizeOfInBits)))
391  return nullptr;
392 
393  // Check that 'Count' is a call to intrinsic cttz/ctlz. Also check that the
394  // input to the cttz/ctlz is used as LHS for the compare instruction.
395  if (match(Count, m_Intrinsic<Intrinsic::cttz>(m_Specific(CmpLHS))) ||
396  match(Count, m_Intrinsic<Intrinsic::ctlz>(m_Specific(CmpLHS)))) {
397  IntrinsicInst *II = cast<IntrinsicInst>(Count);
398  IRBuilder<> Builder(II);
399  // Explicitly clear the 'undef_on_zero' flag.
400  IntrinsicInst *NewI = cast<IntrinsicInst>(II->clone());
401  Type *Ty = NewI->getArgOperand(1)->getType();
403  Builder.Insert(NewI);
404  return Builder.CreateZExtOrTrunc(NewI, ValueOnZero->getType());
405  }
406 
407  return nullptr;
408 }
409 
410 /// Return true if we find and adjust an icmp+select pattern where the compare
411 /// is with a constant that can be incremented or decremented to match the
412 /// minimum or maximum idiom.
413 static bool adjustMinMax(SelectInst &Sel, ICmpInst &Cmp) {
414  ICmpInst::Predicate Pred = Cmp.getPredicate();
415  Value *CmpLHS = Cmp.getOperand(0);
416  Value *CmpRHS = Cmp.getOperand(1);
417  Value *TrueVal = Sel.getTrueValue();
418  Value *FalseVal = Sel.getFalseValue();
419 
420  // We may move or edit the compare, so make sure the select is the only user.
421  const APInt *CmpC;
422  if (!Cmp.hasOneUse() || !match(CmpRHS, m_APInt(CmpC)))
423  return false;
424 
425  // These transforms only work for selects of integers or vector selects of
426  // integer vectors.
427  Type *SelTy = Sel.getType();
428  auto *SelEltTy = dyn_cast<IntegerType>(SelTy->getScalarType());
429  if (!SelEltTy || SelTy->isVectorTy() != Cmp.getType()->isVectorTy())
430  return false;
431 
432  Constant *AdjustedRHS;
433  if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_SGT)
434  AdjustedRHS = ConstantInt::get(CmpRHS->getType(), *CmpC + 1);
435  else if (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_SLT)
436  AdjustedRHS = ConstantInt::get(CmpRHS->getType(), *CmpC - 1);
437  else
438  return false;
439 
440  // X > C ? X : C+1 --> X < C+1 ? C+1 : X
441  // X < C ? X : C-1 --> X > C-1 ? C-1 : X
442  if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) ||
443  (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) {
444  ; // Nothing to do here. Values match without any sign/zero extension.
445  }
446  // Types do not match. Instead of calculating this with mixed types, promote
447  // all to the larger type. This enables scalar evolution to analyze this
448  // expression.
449  else if (CmpRHS->getType()->getScalarSizeInBits() < SelEltTy->getBitWidth()) {
450  Constant *SextRHS = ConstantExpr::getSExt(AdjustedRHS, SelTy);
451 
452  // X = sext x; x >s c ? X : C+1 --> X = sext x; X <s C+1 ? C+1 : X
453  // X = sext x; x <s c ? X : C-1 --> X = sext x; X >s C-1 ? C-1 : X
454  // X = sext x; x >u c ? X : C+1 --> X = sext x; X <u C+1 ? C+1 : X
455  // X = sext x; x <u c ? X : C-1 --> X = sext x; X >u C-1 ? C-1 : X
456  if (match(TrueVal, m_SExt(m_Specific(CmpLHS))) && SextRHS == FalseVal) {
457  CmpLHS = TrueVal;
458  AdjustedRHS = SextRHS;
459  } else if (match(FalseVal, m_SExt(m_Specific(CmpLHS))) &&
460  SextRHS == TrueVal) {
461  CmpLHS = FalseVal;
462  AdjustedRHS = SextRHS;
463  } else if (Cmp.isUnsigned()) {
464  Constant *ZextRHS = ConstantExpr::getZExt(AdjustedRHS, SelTy);
465  // X = zext x; x >u c ? X : C+1 --> X = zext x; X <u C+1 ? C+1 : X
466  // X = zext x; x <u c ? X : C-1 --> X = zext x; X >u C-1 ? C-1 : X
467  // zext + signed compare cannot be changed:
468  // 0xff <s 0x00, but 0x00ff >s 0x0000
469  if (match(TrueVal, m_ZExt(m_Specific(CmpLHS))) && ZextRHS == FalseVal) {
470  CmpLHS = TrueVal;
471  AdjustedRHS = ZextRHS;
472  } else if (match(FalseVal, m_ZExt(m_Specific(CmpLHS))) &&
473  ZextRHS == TrueVal) {
474  CmpLHS = FalseVal;
475  AdjustedRHS = ZextRHS;
476  } else {
477  return false;
478  }
479  } else {
480  return false;
481  }
482  } else {
483  return false;
484  }
485 
486  Pred = ICmpInst::getSwappedPredicate(Pred);
487  CmpRHS = AdjustedRHS;
488  std::swap(FalseVal, TrueVal);
489  Cmp.setPredicate(Pred);
490  Cmp.setOperand(0, CmpLHS);
491  Cmp.setOperand(1, CmpRHS);
492  Sel.setOperand(1, TrueVal);
493  Sel.setOperand(2, FalseVal);
494  Sel.swapProfMetadata();
495 
496  // Move the compare instruction right before the select instruction. Otherwise
497  // the sext/zext value may be defined after the compare instruction uses it.
498  Cmp.moveBefore(&Sel);
499 
500  return true;
501 }
502 
503 /// If this is an integer min/max where the select's 'true' operand is a
504 /// constant, canonicalize that constant to the 'false' operand:
505 /// select (icmp Pred X, C), C, X --> select (icmp Pred' X, C), X, C
506 static Instruction *
507 canonicalizeMinMaxWithConstant(SelectInst &Sel, ICmpInst &Cmp,
508  InstCombiner::BuilderTy &Builder) {
509  // TODO: We should also canonicalize min/max when the select has a different
510  // constant value than the cmp constant, but we need to fix the backend first.
511  if (!Cmp.hasOneUse() || !isa<Constant>(Cmp.getOperand(1)) ||
512  !isa<Constant>(Sel.getTrueValue()) ||
513  isa<Constant>(Sel.getFalseValue()) ||
514  Cmp.getOperand(1) != Sel.getTrueValue())
515  return nullptr;
516 
517  // Canonicalize the compare predicate based on whether we have min or max.
518  Value *LHS, *RHS;
519  ICmpInst::Predicate NewPred;
520  SelectPatternResult SPR = matchSelectPattern(&Sel, LHS, RHS);
521  switch (SPR.Flavor) {
522  case SPF_SMIN: NewPred = ICmpInst::ICMP_SLT; break;
523  case SPF_UMIN: NewPred = ICmpInst::ICMP_ULT; break;
524  case SPF_SMAX: NewPred = ICmpInst::ICMP_SGT; break;
525  case SPF_UMAX: NewPred = ICmpInst::ICMP_UGT; break;
526  default: return nullptr;
527  }
528 
529  // Canonicalize the constant to the right side.
530  if (isa<Constant>(LHS))
531  std::swap(LHS, RHS);
532 
533  Value *NewCmp = Builder.CreateICmp(NewPred, LHS, RHS);
534  SelectInst *NewSel = SelectInst::Create(NewCmp, LHS, RHS, "", nullptr, &Sel);
535 
536  // We swapped the select operands, so swap the metadata too.
537  NewSel->swapProfMetadata();
538  return NewSel;
539 }
540 
541 /// Visit a SelectInst that has an ICmpInst as its first operand.
542 Instruction *InstCombiner::foldSelectInstWithICmp(SelectInst &SI,
543  ICmpInst *ICI) {
544  if (Instruction *NewSel = canonicalizeMinMaxWithConstant(SI, *ICI, *Builder))
545  return NewSel;
546 
547  bool Changed = adjustMinMax(SI, *ICI);
548 
549  ICmpInst::Predicate Pred = ICI->getPredicate();
550  Value *CmpLHS = ICI->getOperand(0);
551  Value *CmpRHS = ICI->getOperand(1);
552  Value *TrueVal = SI.getTrueValue();
553  Value *FalseVal = SI.getFalseValue();
554 
555  // Transform (X >s -1) ? C1 : C2 --> ((X >>s 31) & (C2 - C1)) + C1
556  // and (X <s 0) ? C2 : C1 --> ((X >>s 31) & (C2 - C1)) + C1
557  // FIXME: Type and constness constraints could be lifted, but we have to
558  // watch code size carefully. We should consider xor instead of
559  // sub/add when we decide to do that.
560  if (IntegerType *Ty = dyn_cast<IntegerType>(CmpLHS->getType())) {
561  if (TrueVal->getType() == Ty) {
562  if (ConstantInt *Cmp = dyn_cast<ConstantInt>(CmpRHS)) {
563  ConstantInt *C1 = nullptr, *C2 = nullptr;
564  if (Pred == ICmpInst::ICMP_SGT && Cmp->isAllOnesValue()) {
565  C1 = dyn_cast<ConstantInt>(TrueVal);
566  C2 = dyn_cast<ConstantInt>(FalseVal);
567  } else if (Pred == ICmpInst::ICMP_SLT && Cmp->isNullValue()) {
568  C1 = dyn_cast<ConstantInt>(FalseVal);
569  C2 = dyn_cast<ConstantInt>(TrueVal);
570  }
571  if (C1 && C2) {
572  // This shift results in either -1 or 0.
573  Value *AShr = Builder->CreateAShr(CmpLHS, Ty->getBitWidth()-1);
574 
575  // Check if we can express the operation with a single or.
576  if (C2->isAllOnesValue())
577  return replaceInstUsesWith(SI, Builder->CreateOr(AShr, C1));
578 
579  Value *And = Builder->CreateAnd(AShr, C2->getValue()-C1->getValue());
580  return replaceInstUsesWith(SI, Builder->CreateAdd(And, C1));
581  }
582  }
583  }
584  }
585 
586  // NOTE: if we wanted to, this is where to detect integer MIN/MAX
587 
588  if (CmpRHS != CmpLHS && isa<Constant>(CmpRHS)) {
589  if (CmpLHS == TrueVal && Pred == ICmpInst::ICMP_EQ) {
590  // Transform (X == C) ? X : Y -> (X == C) ? C : Y
591  SI.setOperand(1, CmpRHS);
592  Changed = true;
593  } else if (CmpLHS == FalseVal && Pred == ICmpInst::ICMP_NE) {
594  // Transform (X != C) ? Y : X -> (X != C) ? Y : C
595  SI.setOperand(2, CmpRHS);
596  Changed = true;
597  }
598  }
599 
600  // FIXME: This code is nearly duplicated in InstSimplify. Using/refactoring
601  // decomposeBitTestICmp() might help.
602  {
603  unsigned BitWidth =
604  DL.getTypeSizeInBits(TrueVal->getType()->getScalarType());
605  APInt MinSignedValue = APInt::getSignBit(BitWidth);
606  Value *X;
607  const APInt *Y, *C;
608  bool TrueWhenUnset;
609  bool IsBitTest = false;
610  if (ICmpInst::isEquality(Pred) &&
611  match(CmpLHS, m_And(m_Value(X), m_Power2(Y))) &&
612  match(CmpRHS, m_Zero())) {
613  IsBitTest = true;
614  TrueWhenUnset = Pred == ICmpInst::ICMP_EQ;
615  } else if (Pred == ICmpInst::ICMP_SLT && match(CmpRHS, m_Zero())) {
616  X = CmpLHS;
617  Y = &MinSignedValue;
618  IsBitTest = true;
619  TrueWhenUnset = false;
620  } else if (Pred == ICmpInst::ICMP_SGT && match(CmpRHS, m_AllOnes())) {
621  X = CmpLHS;
622  Y = &MinSignedValue;
623  IsBitTest = true;
624  TrueWhenUnset = true;
625  }
626  if (IsBitTest) {
627  Value *V = nullptr;
628  // (X & Y) == 0 ? X : X ^ Y --> X & ~Y
629  if (TrueWhenUnset && TrueVal == X &&
630  match(FalseVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
631  V = Builder->CreateAnd(X, ~(*Y));
632  // (X & Y) != 0 ? X ^ Y : X --> X & ~Y
633  else if (!TrueWhenUnset && FalseVal == X &&
634  match(TrueVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
635  V = Builder->CreateAnd(X, ~(*Y));
636  // (X & Y) == 0 ? X ^ Y : X --> X | Y
637  else if (TrueWhenUnset && FalseVal == X &&
638  match(TrueVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
639  V = Builder->CreateOr(X, *Y);
640  // (X & Y) != 0 ? X : X ^ Y --> X | Y
641  else if (!TrueWhenUnset && TrueVal == X &&
642  match(FalseVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
643  V = Builder->CreateOr(X, *Y);
644 
645  if (V)
646  return replaceInstUsesWith(SI, V);
647  }
648  }
649 
650  if (Value *V = foldSelectICmpAndOr(SI, TrueVal, FalseVal, Builder))
651  return replaceInstUsesWith(SI, V);
652 
653  if (Value *V = foldSelectCttzCtlz(ICI, TrueVal, FalseVal, Builder))
654  return replaceInstUsesWith(SI, V);
655 
656  return Changed ? &SI : nullptr;
657 }
658 
659 
660 /// SI is a select whose condition is a PHI node (but the two may be in
661 /// different blocks). See if the true/false values (V) are live in all of the
662 /// predecessor blocks of the PHI. For example, cases like this can't be mapped:
663 ///
664 /// X = phi [ C1, BB1], [C2, BB2]
665 /// Y = add
666 /// Z = select X, Y, 0
667 ///
668 /// because Y is not live in BB1/BB2.
669 ///
670 static bool canSelectOperandBeMappingIntoPredBlock(const Value *V,
671  const SelectInst &SI) {
672  // If the value is a non-instruction value like a constant or argument, it
673  // can always be mapped.
674  const Instruction *I = dyn_cast<Instruction>(V);
675  if (!I) return true;
676 
677  // If V is a PHI node defined in the same block as the condition PHI, we can
678  // map the arguments.
679  const PHINode *CondPHI = cast<PHINode>(SI.getCondition());
680 
681  if (const PHINode *VP = dyn_cast<PHINode>(I))
682  if (VP->getParent() == CondPHI->getParent())
683  return true;
684 
685  // Otherwise, if the PHI and select are defined in the same block and if V is
686  // defined in a different block, then we can transform it.
687  if (SI.getParent() == CondPHI->getParent() &&
688  I->getParent() != CondPHI->getParent())
689  return true;
690 
691  // Otherwise we have a 'hard' case and we can't tell without doing more
692  // detailed dominator based analysis, punt.
693  return false;
694 }
695 
696 /// We have an SPF (e.g. a min or max) of an SPF of the form:
697 /// SPF2(SPF1(A, B), C)
698 Instruction *InstCombiner::foldSPFofSPF(Instruction *Inner,
699  SelectPatternFlavor SPF1,
700  Value *A, Value *B,
701  Instruction &Outer,
702  SelectPatternFlavor SPF2, Value *C) {
703  if (Outer.getType() != Inner->getType())
704  return nullptr;
705 
706  if (C == A || C == B) {
707  // MAX(MAX(A, B), B) -> MAX(A, B)
708  // MIN(MIN(a, b), a) -> MIN(a, b)
709  if (SPF1 == SPF2)
710  return replaceInstUsesWith(Outer, Inner);
711 
712  // MAX(MIN(a, b), a) -> a
713  // MIN(MAX(a, b), a) -> a
714  if ((SPF1 == SPF_SMIN && SPF2 == SPF_SMAX) ||
715  (SPF1 == SPF_SMAX && SPF2 == SPF_SMIN) ||
716  (SPF1 == SPF_UMIN && SPF2 == SPF_UMAX) ||
717  (SPF1 == SPF_UMAX && SPF2 == SPF_UMIN))
718  return replaceInstUsesWith(Outer, C);
719  }
720 
721  if (SPF1 == SPF2) {
722  const APInt *CB, *CC;
723  if (match(B, m_APInt(CB)) && match(C, m_APInt(CC))) {
724  // MIN(MIN(A, 23), 97) -> MIN(A, 23)
725  // MAX(MAX(A, 97), 23) -> MAX(A, 97)
726  if ((SPF1 == SPF_UMIN && CB->ule(*CC)) ||
727  (SPF1 == SPF_SMIN && CB->sle(*CC)) ||
728  (SPF1 == SPF_UMAX && CB->uge(*CC)) ||
729  (SPF1 == SPF_SMAX && CB->sge(*CC)))
730  return replaceInstUsesWith(Outer, Inner);
731 
732  // MIN(MIN(A, 97), 23) -> MIN(A, 23)
733  // MAX(MAX(A, 23), 97) -> MAX(A, 97)
734  if ((SPF1 == SPF_UMIN && CB->ugt(*CC)) ||
735  (SPF1 == SPF_SMIN && CB->sgt(*CC)) ||
736  (SPF1 == SPF_UMAX && CB->ult(*CC)) ||
737  (SPF1 == SPF_SMAX && CB->slt(*CC))) {
738  Outer.replaceUsesOfWith(Inner, A);
739  return &Outer;
740  }
741  }
742  }
743 
744  // ABS(ABS(X)) -> ABS(X)
745  // NABS(NABS(X)) -> NABS(X)
746  if (SPF1 == SPF2 && (SPF1 == SPF_ABS || SPF1 == SPF_NABS)) {
747  return replaceInstUsesWith(Outer, Inner);
748  }
749 
750  // ABS(NABS(X)) -> ABS(X)
751  // NABS(ABS(X)) -> NABS(X)
752  if ((SPF1 == SPF_ABS && SPF2 == SPF_NABS) ||
753  (SPF1 == SPF_NABS && SPF2 == SPF_ABS)) {
754  SelectInst *SI = cast<SelectInst>(Inner);
755  Value *NewSI =
756  Builder->CreateSelect(SI->getCondition(), SI->getFalseValue(),
757  SI->getTrueValue(), SI->getName(), SI);
758  return replaceInstUsesWith(Outer, NewSI);
759  }
760 
761  auto IsFreeOrProfitableToInvert =
762  [&](Value *V, Value *&NotV, bool &ElidesXor) {
763  if (match(V, m_Not(m_Value(NotV)))) {
764  // If V has at most 2 uses then we can get rid of the xor operation
765  // entirely.
766  ElidesXor |= !V->hasNUsesOrMore(3);
767  return true;
768  }
769 
770  if (IsFreeToInvert(V, !V->hasNUsesOrMore(3))) {
771  NotV = nullptr;
772  return true;
773  }
774 
775  return false;
776  };
777 
778  Value *NotA, *NotB, *NotC;
779  bool ElidesXor = false;
780 
781  // MIN(MIN(~A, ~B), ~C) == ~MAX(MAX(A, B), C)
782  // MIN(MAX(~A, ~B), ~C) == ~MAX(MIN(A, B), C)
783  // MAX(MIN(~A, ~B), ~C) == ~MIN(MAX(A, B), C)
784  // MAX(MAX(~A, ~B), ~C) == ~MIN(MIN(A, B), C)
785  //
786  // This transform is performance neutral if we can elide at least one xor from
787  // the set of three operands, since we'll be tacking on an xor at the very
788  // end.
789  if (IsFreeOrProfitableToInvert(A, NotA, ElidesXor) &&
790  IsFreeOrProfitableToInvert(B, NotB, ElidesXor) &&
791  IsFreeOrProfitableToInvert(C, NotC, ElidesXor) && ElidesXor) {
792  if (!NotA)
793  NotA = Builder->CreateNot(A);
794  if (!NotB)
795  NotB = Builder->CreateNot(B);
796  if (!NotC)
797  NotC = Builder->CreateNot(C);
798 
800  Builder, getInverseMinMaxSelectPattern(SPF1), NotA, NotB);
801  Value *NewOuter = Builder->CreateNot(generateMinMaxSelectPattern(
802  Builder, getInverseMinMaxSelectPattern(SPF2), NewInner, NotC));
803  return replaceInstUsesWith(Outer, NewOuter);
804  }
805 
806  return nullptr;
807 }
808 
809 /// If one of the constants is zero (we know they can't both be) and we have an
810 /// icmp instruction with zero, and we have an 'and' with the non-constant value
811 /// and a power of two we can turn the select into a shift on the result of the
812 /// 'and'.
813 static Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal,
814  ConstantInt *FalseVal,
815  InstCombiner::BuilderTy *Builder) {
816  const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition());
817  if (!IC || !IC->isEquality() || !SI.getType()->isIntegerTy())
818  return nullptr;
819 
820  if (!match(IC->getOperand(1), m_Zero()))
821  return nullptr;
822 
823  ConstantInt *AndRHS;
824  Value *LHS = IC->getOperand(0);
825  if (!match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS))))
826  return nullptr;
827 
828  // If both select arms are non-zero see if we have a select of the form
829  // 'x ? 2^n + C : C'. Then we can offset both arms by C, use the logic
830  // for 'x ? 2^n : 0' and fix the thing up at the end.
831  ConstantInt *Offset = nullptr;
832  if (!TrueVal->isZero() && !FalseVal->isZero()) {
833  if ((TrueVal->getValue() - FalseVal->getValue()).isPowerOf2())
834  Offset = FalseVal;
835  else if ((FalseVal->getValue() - TrueVal->getValue()).isPowerOf2())
836  Offset = TrueVal;
837  else
838  return nullptr;
839 
840  // Adjust TrueVal and FalseVal to the offset.
841  TrueVal = ConstantInt::get(Builder->getContext(),
842  TrueVal->getValue() - Offset->getValue());
843  FalseVal = ConstantInt::get(Builder->getContext(),
844  FalseVal->getValue() - Offset->getValue());
845  }
846 
847  // Make sure the mask in the 'and' and one of the select arms is a power of 2.
848  if (!AndRHS->getValue().isPowerOf2() ||
849  (!TrueVal->getValue().isPowerOf2() &&
850  !FalseVal->getValue().isPowerOf2()))
851  return nullptr;
852 
853  // Determine which shift is needed to transform result of the 'and' into the
854  // desired result.
855  ConstantInt *ValC = !TrueVal->isZero() ? TrueVal : FalseVal;
856  unsigned ValZeros = ValC->getValue().logBase2();
857  unsigned AndZeros = AndRHS->getValue().logBase2();
858 
859  // If types don't match we can still convert the select by introducing a zext
860  // or a trunc of the 'and'. The trunc case requires that all of the truncated
861  // bits are zero, we can figure that out by looking at the 'and' mask.
862  if (AndZeros >= ValC->getBitWidth())
863  return nullptr;
864 
865  Value *V = Builder->CreateZExtOrTrunc(LHS, SI.getType());
866  if (ValZeros > AndZeros)
867  V = Builder->CreateShl(V, ValZeros - AndZeros);
868  else if (ValZeros < AndZeros)
869  V = Builder->CreateLShr(V, AndZeros - ValZeros);
870 
871  // Okay, now we know that everything is set up, we just don't know whether we
872  // have a icmp_ne or icmp_eq and whether the true or false val is the zero.
873  bool ShouldNotVal = !TrueVal->isZero();
874  ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE;
875  if (ShouldNotVal)
876  V = Builder->CreateXor(V, ValC);
877 
878  // Apply an offset if needed.
879  if (Offset)
880  V = Builder->CreateAdd(V, Offset);
881  return V;
882 }
883 
884 /// Turn select C, (X + Y), (X - Y) --> (X + (select C, Y, (-Y))).
885 /// This is even legal for FP.
886 static Instruction *foldAddSubSelect(SelectInst &SI,
887  InstCombiner::BuilderTy &Builder) {
888  Value *CondVal = SI.getCondition();
889  Value *TrueVal = SI.getTrueValue();
890  Value *FalseVal = SI.getFalseValue();
891  auto *TI = dyn_cast<Instruction>(TrueVal);
892  auto *FI = dyn_cast<Instruction>(FalseVal);
893  if (!TI || !FI || !TI->hasOneUse() || !FI->hasOneUse())
894  return nullptr;
895 
896  Instruction *AddOp = nullptr, *SubOp = nullptr;
897  if ((TI->getOpcode() == Instruction::Sub &&
898  FI->getOpcode() == Instruction::Add) ||
899  (TI->getOpcode() == Instruction::FSub &&
900  FI->getOpcode() == Instruction::FAdd)) {
901  AddOp = FI;
902  SubOp = TI;
903  } else if ((FI->getOpcode() == Instruction::Sub &&
904  TI->getOpcode() == Instruction::Add) ||
905  (FI->getOpcode() == Instruction::FSub &&
906  TI->getOpcode() == Instruction::FAdd)) {
907  AddOp = TI;
908  SubOp = FI;
909  }
910 
911  if (AddOp) {
912  Value *OtherAddOp = nullptr;
913  if (SubOp->getOperand(0) == AddOp->getOperand(0)) {
914  OtherAddOp = AddOp->getOperand(1);
915  } else if (SubOp->getOperand(0) == AddOp->getOperand(1)) {
916  OtherAddOp = AddOp->getOperand(0);
917  }
918 
919  if (OtherAddOp) {
920  // So at this point we know we have (Y -> OtherAddOp):
921  // select C, (add X, Y), (sub X, Z)
922  Value *NegVal; // Compute -Z
923  if (SI.getType()->isFPOrFPVectorTy()) {
924  NegVal = Builder.CreateFNeg(SubOp->getOperand(1));
925  if (Instruction *NegInst = dyn_cast<Instruction>(NegVal)) {
927  Flags &= SubOp->getFastMathFlags();
928  NegInst->setFastMathFlags(Flags);
929  }
930  } else {
931  NegVal = Builder.CreateNeg(SubOp->getOperand(1));
932  }
933 
934  Value *NewTrueOp = OtherAddOp;
935  Value *NewFalseOp = NegVal;
936  if (AddOp != TI)
937  std::swap(NewTrueOp, NewFalseOp);
938  Value *NewSel = Builder.CreateSelect(CondVal, NewTrueOp, NewFalseOp,
939  SI.getName() + ".p", &SI);
940 
941  if (SI.getType()->isFPOrFPVectorTy()) {
942  Instruction *RI =
943  BinaryOperator::CreateFAdd(SubOp->getOperand(0), NewSel);
944 
945  FastMathFlags Flags = AddOp->getFastMathFlags();
946  Flags &= SubOp->getFastMathFlags();
947  RI->setFastMathFlags(Flags);
948  return RI;
949  } else
950  return BinaryOperator::CreateAdd(SubOp->getOperand(0), NewSel);
951  }
952  }
953  return nullptr;
954 }
955 
956 Instruction *InstCombiner::foldSelectExtConst(SelectInst &Sel) {
957  Instruction *ExtInst;
958  if (!match(Sel.getTrueValue(), m_Instruction(ExtInst)) &&
959  !match(Sel.getFalseValue(), m_Instruction(ExtInst)))
960  return nullptr;
961 
962  auto ExtOpcode = ExtInst->getOpcode();
963  if (ExtOpcode != Instruction::ZExt && ExtOpcode != Instruction::SExt)
964  return nullptr;
965 
966  // TODO: Handle larger types? That requires adjusting FoldOpIntoSelect too.
967  Value *X = ExtInst->getOperand(0);
968  Type *SmallType = X->getType();
969  if (!SmallType->getScalarType()->isIntegerTy(1))
970  return nullptr;
971 
972  Constant *C;
973  if (!match(Sel.getTrueValue(), m_Constant(C)) &&
974  !match(Sel.getFalseValue(), m_Constant(C)))
975  return nullptr;
976 
977  // If the constant is the same after truncation to the smaller type and
978  // extension to the original type, we can narrow the select.
979  Value *Cond = Sel.getCondition();
980  Type *SelType = Sel.getType();
981  Constant *TruncC = ConstantExpr::getTrunc(C, SmallType);
982  Constant *ExtC = ConstantExpr::getCast(ExtOpcode, TruncC, SelType);
983  if (ExtC == C) {
984  Value *TruncCVal = cast<Value>(TruncC);
985  if (ExtInst == Sel.getFalseValue())
986  std::swap(X, TruncCVal);
987 
988  // select Cond, (ext X), C --> ext(select Cond, X, C')
989  // select Cond, C, (ext X) --> ext(select Cond, C', X)
990  Value *NewSel = Builder->CreateSelect(Cond, X, TruncCVal, "narrow", &Sel);
991  return CastInst::Create(Instruction::CastOps(ExtOpcode), NewSel, SelType);
992  }
993 
994  // If one arm of the select is the extend of the condition, replace that arm
995  // with the extension of the appropriate known bool value.
996  if (Cond == X) {
997  if (ExtInst == Sel.getTrueValue()) {
998  // select X, (sext X), C --> select X, -1, C
999  // select X, (zext X), C --> select X, 1, C
1000  Constant *One = ConstantInt::getTrue(SmallType);
1001  Constant *AllOnesOrOne = ConstantExpr::getCast(ExtOpcode, One, SelType);
1002  return SelectInst::Create(Cond, AllOnesOrOne, C, "", nullptr, &Sel);
1003  } else {
1004  // select X, C, (sext X) --> select X, C, 0
1005  // select X, C, (zext X) --> select X, C, 0
1007  return SelectInst::Create(Cond, C, Zero, "", nullptr, &Sel);
1008  }
1009  }
1010 
1011  return nullptr;
1012 }
1013 
1014 /// Try to transform a vector select with a constant condition vector into a
1015 /// shuffle for easier combining with other shuffles and insert/extract.
1016 static Instruction *canonicalizeSelectToShuffle(SelectInst &SI) {
1017  Value *CondVal = SI.getCondition();
1018  Constant *CondC;
1019  if (!CondVal->getType()->isVectorTy() || !match(CondVal, m_Constant(CondC)))
1020  return nullptr;
1021 
1022  unsigned NumElts = CondVal->getType()->getVectorNumElements();
1024  Mask.reserve(NumElts);
1025  Type *Int32Ty = Type::getInt32Ty(CondVal->getContext());
1026  for (unsigned i = 0; i != NumElts; ++i) {
1027  Constant *Elt = CondC->getAggregateElement(i);
1028  if (!Elt)
1029  return nullptr;
1030 
1031  if (Elt->isOneValue()) {
1032  // If the select condition element is true, choose from the 1st vector.
1033  Mask.push_back(ConstantInt::get(Int32Ty, i));
1034  } else if (Elt->isNullValue()) {
1035  // If the select condition element is false, choose from the 2nd vector.
1036  Mask.push_back(ConstantInt::get(Int32Ty, i + NumElts));
1037  } else if (isa<UndefValue>(Elt)) {
1038  // If the select condition element is undef, the shuffle mask is undef.
1039  Mask.push_back(UndefValue::get(Int32Ty));
1040  } else {
1041  // Bail out on a constant expression.
1042  return nullptr;
1043  }
1044  }
1045 
1046  return new ShuffleVectorInst(SI.getTrueValue(), SI.getFalseValue(),
1047  ConstantVector::get(Mask));
1048 }
1049 
1050 /// Reuse bitcasted operands between a compare and select:
1051 /// select (cmp (bitcast C), (bitcast D)), (bitcast' C), (bitcast' D) -->
1052 /// bitcast (select (cmp (bitcast C), (bitcast D)), (bitcast C), (bitcast D))
1053 static Instruction *foldSelectCmpBitcasts(SelectInst &Sel,
1054  InstCombiner::BuilderTy &Builder) {
1055  Value *Cond = Sel.getCondition();
1056  Value *TVal = Sel.getTrueValue();
1057  Value *FVal = Sel.getFalseValue();
1058 
1059  CmpInst::Predicate Pred;
1060  Value *A, *B;
1061  if (!match(Cond, m_Cmp(Pred, m_Value(A), m_Value(B))))
1062  return nullptr;
1063 
1064  // The select condition is a compare instruction. If the select's true/false
1065  // values are already the same as the compare operands, there's nothing to do.
1066  if (TVal == A || TVal == B || FVal == A || FVal == B)
1067  return nullptr;
1068 
1069  Value *C, *D;
1070  if (!match(A, m_BitCast(m_Value(C))) || !match(B, m_BitCast(m_Value(D))))
1071  return nullptr;
1072 
1073  // select (cmp (bitcast C), (bitcast D)), (bitcast TSrc), (bitcast FSrc)
1074  Value *TSrc, *FSrc;
1075  if (!match(TVal, m_BitCast(m_Value(TSrc))) ||
1076  !match(FVal, m_BitCast(m_Value(FSrc))))
1077  return nullptr;
1078 
1079  // If the select true/false values are *different bitcasts* of the same source
1080  // operands, make the select operands the same as the compare operands and
1081  // cast the result. This is the canonical select form for min/max.
1082  Value *NewSel;
1083  if (TSrc == C && FSrc == D) {
1084  // select (cmp (bitcast C), (bitcast D)), (bitcast' C), (bitcast' D) -->
1085  // bitcast (select (cmp A, B), A, B)
1086  NewSel = Builder.CreateSelect(Cond, A, B, "", &Sel);
1087  } else if (TSrc == D && FSrc == C) {
1088  // select (cmp (bitcast C), (bitcast D)), (bitcast' D), (bitcast' C) -->
1089  // bitcast (select (cmp A, B), B, A)
1090  NewSel = Builder.CreateSelect(Cond, B, A, "", &Sel);
1091  } else {
1092  return nullptr;
1093  }
1094  return CastInst::CreateBitOrPointerCast(NewSel, Sel.getType());
1095 }
1096 
1098  Value *CondVal = SI.getCondition();
1099  Value *TrueVal = SI.getTrueValue();
1100  Value *FalseVal = SI.getFalseValue();
1101  Type *SelType = SI.getType();
1102 
1103  if (Value *V =
1104  SimplifySelectInst(CondVal, TrueVal, FalseVal, DL, &TLI, &DT, &AC))
1105  return replaceInstUsesWith(SI, V);
1106 
1107  if (Instruction *I = canonicalizeSelectToShuffle(SI))
1108  return I;
1109 
1110  if (SelType->getScalarType()->isIntegerTy(1) &&
1111  TrueVal->getType() == CondVal->getType()) {
1112  if (match(TrueVal, m_One())) {
1113  // Change: A = select B, true, C --> A = or B, C
1114  return BinaryOperator::CreateOr(CondVal, FalseVal);
1115  }
1116  if (match(TrueVal, m_Zero())) {
1117  // Change: A = select B, false, C --> A = and !B, C
1118  Value *NotCond = Builder->CreateNot(CondVal, "not." + CondVal->getName());
1119  return BinaryOperator::CreateAnd(NotCond, FalseVal);
1120  }
1121  if (match(FalseVal, m_Zero())) {
1122  // Change: A = select B, C, false --> A = and B, C
1123  return BinaryOperator::CreateAnd(CondVal, TrueVal);
1124  }
1125  if (match(FalseVal, m_One())) {
1126  // Change: A = select B, C, true --> A = or !B, C
1127  Value *NotCond = Builder->CreateNot(CondVal, "not." + CondVal->getName());
1128  return BinaryOperator::CreateOr(NotCond, TrueVal);
1129  }
1130 
1131  // select a, a, b -> a | b
1132  // select a, b, a -> a & b
1133  if (CondVal == TrueVal)
1134  return BinaryOperator::CreateOr(CondVal, FalseVal);
1135  if (CondVal == FalseVal)
1136  return BinaryOperator::CreateAnd(CondVal, TrueVal);
1137 
1138  // select a, ~a, b -> (~a) & b
1139  // select a, b, ~a -> (~a) | b
1140  if (match(TrueVal, m_Not(m_Specific(CondVal))))
1141  return BinaryOperator::CreateAnd(TrueVal, FalseVal);
1142  if (match(FalseVal, m_Not(m_Specific(CondVal))))
1143  return BinaryOperator::CreateOr(TrueVal, FalseVal);
1144  }
1145 
1146  // Selecting between two integer or vector splat integer constants?
1147  //
1148  // Note that we don't handle a scalar select of vectors:
1149  // select i1 %c, <2 x i8> <1, 1>, <2 x i8> <0, 0>
1150  // because that may need 3 instructions to splat the condition value:
1151  // extend, insertelement, shufflevector.
1152  if (CondVal->getType()->isVectorTy() == SelType->isVectorTy()) {
1153  // select C, 1, 0 -> zext C to int
1154  if (match(TrueVal, m_One()) && match(FalseVal, m_Zero()))
1155  return new ZExtInst(CondVal, SelType);
1156 
1157  // select C, -1, 0 -> sext C to int
1158  if (match(TrueVal, m_AllOnes()) && match(FalseVal, m_Zero()))
1159  return new SExtInst(CondVal, SelType);
1160 
1161  // select C, 0, 1 -> zext !C to int
1162  if (match(TrueVal, m_Zero()) && match(FalseVal, m_One())) {
1163  Value *NotCond = Builder->CreateNot(CondVal, "not." + CondVal->getName());
1164  return new ZExtInst(NotCond, SelType);
1165  }
1166 
1167  // select C, 0, -1 -> sext !C to int
1168  if (match(TrueVal, m_Zero()) && match(FalseVal, m_AllOnes())) {
1169  Value *NotCond = Builder->CreateNot(CondVal, "not." + CondVal->getName());
1170  return new SExtInst(NotCond, SelType);
1171  }
1172  }
1173 
1174  if (ConstantInt *TrueValC = dyn_cast<ConstantInt>(TrueVal))
1175  if (ConstantInt *FalseValC = dyn_cast<ConstantInt>(FalseVal))
1176  if (Value *V = foldSelectICmpAnd(SI, TrueValC, FalseValC, Builder))
1177  return replaceInstUsesWith(SI, V);
1178 
1179  // See if we are selecting two values based on a comparison of the two values.
1180  if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) {
1181  if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) {
1182  // Transform (X == Y) ? X : Y -> Y
1183  if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) {
1184  // This is not safe in general for floating point:
1185  // consider X== -0, Y== +0.
1186  // It becomes safe if either operand is a nonzero constant.
1187  ConstantFP *CFPt, *CFPf;
1188  if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
1189  !CFPt->getValueAPF().isZero()) ||
1190  ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
1191  !CFPf->getValueAPF().isZero()))
1192  return replaceInstUsesWith(SI, FalseVal);
1193  }
1194  // Transform (X une Y) ? X : Y -> X
1195  if (FCI->getPredicate() == FCmpInst::FCMP_UNE) {
1196  // This is not safe in general for floating point:
1197  // consider X== -0, Y== +0.
1198  // It becomes safe if either operand is a nonzero constant.
1199  ConstantFP *CFPt, *CFPf;
1200  if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
1201  !CFPt->getValueAPF().isZero()) ||
1202  ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
1203  !CFPf->getValueAPF().isZero()))
1204  return replaceInstUsesWith(SI, TrueVal);
1205  }
1206 
1207  // Canonicalize to use ordered comparisons by swapping the select
1208  // operands.
1209  //
1210  // e.g.
1211  // (X ugt Y) ? X : Y -> (X ole Y) ? Y : X
1212  if (FCI->hasOneUse() && FCmpInst::isUnordered(FCI->getPredicate())) {
1213  FCmpInst::Predicate InvPred = FCI->getInversePredicate();
1214  IRBuilder<>::FastMathFlagGuard FMFG(*Builder);
1215  Builder->setFastMathFlags(FCI->getFastMathFlags());
1216  Value *NewCond = Builder->CreateFCmp(InvPred, TrueVal, FalseVal,
1217  FCI->getName() + ".inv");
1218 
1219  return SelectInst::Create(NewCond, FalseVal, TrueVal,
1220  SI.getName() + ".p");
1221  }
1222 
1223  // NOTE: if we wanted to, this is where to detect MIN/MAX
1224  } else if (FCI->getOperand(0) == FalseVal && FCI->getOperand(1) == TrueVal){
1225  // Transform (X == Y) ? Y : X -> X
1226  if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) {
1227  // This is not safe in general for floating point:
1228  // consider X== -0, Y== +0.
1229  // It becomes safe if either operand is a nonzero constant.
1230  ConstantFP *CFPt, *CFPf;
1231  if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
1232  !CFPt->getValueAPF().isZero()) ||
1233  ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
1234  !CFPf->getValueAPF().isZero()))
1235  return replaceInstUsesWith(SI, FalseVal);
1236  }
1237  // Transform (X une Y) ? Y : X -> Y
1238  if (FCI->getPredicate() == FCmpInst::FCMP_UNE) {
1239  // This is not safe in general for floating point:
1240  // consider X== -0, Y== +0.
1241  // It becomes safe if either operand is a nonzero constant.
1242  ConstantFP *CFPt, *CFPf;
1243  if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
1244  !CFPt->getValueAPF().isZero()) ||
1245  ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
1246  !CFPf->getValueAPF().isZero()))
1247  return replaceInstUsesWith(SI, TrueVal);
1248  }
1249 
1250  // Canonicalize to use ordered comparisons by swapping the select
1251  // operands.
1252  //
1253  // e.g.
1254  // (X ugt Y) ? X : Y -> (X ole Y) ? X : Y
1255  if (FCI->hasOneUse() && FCmpInst::isUnordered(FCI->getPredicate())) {
1256  FCmpInst::Predicate InvPred = FCI->getInversePredicate();
1257  IRBuilder<>::FastMathFlagGuard FMFG(*Builder);
1258  Builder->setFastMathFlags(FCI->getFastMathFlags());
1259  Value *NewCond = Builder->CreateFCmp(InvPred, FalseVal, TrueVal,
1260  FCI->getName() + ".inv");
1261 
1262  return SelectInst::Create(NewCond, FalseVal, TrueVal,
1263  SI.getName() + ".p");
1264  }
1265 
1266  // NOTE: if we wanted to, this is where to detect MIN/MAX
1267  }
1268  // NOTE: if we wanted to, this is where to detect ABS
1269  }
1270 
1271  // See if we are selecting two values based on a comparison of the two values.
1272  if (ICmpInst *ICI = dyn_cast<ICmpInst>(CondVal))
1273  if (Instruction *Result = foldSelectInstWithICmp(SI, ICI))
1274  return Result;
1275 
1276  if (Instruction *Add = foldAddSubSelect(SI, *Builder))
1277  return Add;
1278 
1279  // Turn (select C, (op X, Y), (op X, Z)) -> (op X, (select C, Y, Z))
1280  auto *TI = dyn_cast<Instruction>(TrueVal);
1281  auto *FI = dyn_cast<Instruction>(FalseVal);
1282  if (TI && FI && TI->getOpcode() == FI->getOpcode())
1283  if (Instruction *IV = foldSelectOpOp(SI, TI, FI))
1284  return IV;
1285 
1286  if (Instruction *I = foldSelectExtConst(SI))
1287  return I;
1288 
1289  // See if we can fold the select into one of our operands.
1290  if (SelType->isIntOrIntVectorTy() || SelType->isFPOrFPVectorTy()) {
1291  if (Instruction *FoldI = foldSelectIntoOp(SI, TrueVal, FalseVal))
1292  return FoldI;
1293 
1294  Value *LHS, *RHS, *LHS2, *RHS2;
1295  Instruction::CastOps CastOp;
1296  SelectPatternResult SPR = matchSelectPattern(&SI, LHS, RHS, &CastOp);
1297  auto SPF = SPR.Flavor;
1298 
1300  // Canonicalize so that type casts are outside select patterns.
1301  if (LHS->getType()->getPrimitiveSizeInBits() !=
1302  SelType->getPrimitiveSizeInBits()) {
1304 
1305  Value *Cmp;
1306  if (CmpInst::isIntPredicate(Pred)) {
1307  Cmp = Builder->CreateICmp(Pred, LHS, RHS);
1308  } else {
1309  IRBuilder<>::FastMathFlagGuard FMFG(*Builder);
1310  auto FMF = cast<FPMathOperator>(SI.getCondition())->getFastMathFlags();
1311  Builder->setFastMathFlags(FMF);
1312  Cmp = Builder->CreateFCmp(Pred, LHS, RHS);
1313  }
1314 
1315  Value *NewSI = Builder->CreateCast(
1316  CastOp, Builder->CreateSelect(Cmp, LHS, RHS, SI.getName(), &SI),
1317  SelType);
1318  return replaceInstUsesWith(SI, NewSI);
1319  }
1320  }
1321 
1322  if (SPF) {
1323  // MAX(MAX(a, b), a) -> MAX(a, b)
1324  // MIN(MIN(a, b), a) -> MIN(a, b)
1325  // MAX(MIN(a, b), a) -> a
1326  // MIN(MAX(a, b), a) -> a
1327  // ABS(ABS(a)) -> ABS(a)
1328  // NABS(NABS(a)) -> NABS(a)
1329  if (SelectPatternFlavor SPF2 = matchSelectPattern(LHS, LHS2, RHS2).Flavor)
1330  if (Instruction *R = foldSPFofSPF(cast<Instruction>(LHS),SPF2,LHS2,RHS2,
1331  SI, SPF, RHS))
1332  return R;
1333  if (SelectPatternFlavor SPF2 = matchSelectPattern(RHS, LHS2, RHS2).Flavor)
1334  if (Instruction *R = foldSPFofSPF(cast<Instruction>(RHS),SPF2,LHS2,RHS2,
1335  SI, SPF, LHS))
1336  return R;
1337  }
1338 
1339  // MAX(~a, ~b) -> ~MIN(a, b)
1340  if ((SPF == SPF_SMAX || SPF == SPF_UMAX) &&
1341  IsFreeToInvert(LHS, LHS->hasNUses(2)) &&
1342  IsFreeToInvert(RHS, RHS->hasNUses(2))) {
1343  // For this transform to be profitable, we need to eliminate at least two
1344  // 'not' instructions if we're going to add one 'not' instruction.
1345  int NumberOfNots =
1346  (LHS->hasNUses(2) && match(LHS, m_Not(m_Value()))) +
1347  (RHS->hasNUses(2) && match(RHS, m_Not(m_Value()))) +
1348  (SI.hasOneUse() && match(*SI.user_begin(), m_Not(m_Value())));
1349 
1350  if (NumberOfNots >= 2) {
1351  Value *NewLHS = Builder->CreateNot(LHS);
1352  Value *NewRHS = Builder->CreateNot(RHS);
1353  Value *NewCmp = SPF == SPF_SMAX
1354  ? Builder->CreateICmpSLT(NewLHS, NewRHS)
1355  : Builder->CreateICmpULT(NewLHS, NewRHS);
1356  Value *NewSI =
1357  Builder->CreateNot(Builder->CreateSelect(NewCmp, NewLHS, NewRHS));
1358  return replaceInstUsesWith(SI, NewSI);
1359  }
1360  }
1361 
1362  // TODO.
1363  // ABS(-X) -> ABS(X)
1364  }
1365 
1366  // See if we can fold the select into a phi node if the condition is a select.
1367  if (isa<PHINode>(SI.getCondition()))
1368  // The true/false values have to be live in the PHI predecessor's blocks.
1369  if (canSelectOperandBeMappingIntoPredBlock(TrueVal, SI) &&
1370  canSelectOperandBeMappingIntoPredBlock(FalseVal, SI))
1371  if (Instruction *NV = FoldOpIntoPhi(SI))
1372  return NV;
1373 
1374  if (SelectInst *TrueSI = dyn_cast<SelectInst>(TrueVal)) {
1375  if (TrueSI->getCondition()->getType() == CondVal->getType()) {
1376  // select(C, select(C, a, b), c) -> select(C, a, c)
1377  if (TrueSI->getCondition() == CondVal) {
1378  if (SI.getTrueValue() == TrueSI->getTrueValue())
1379  return nullptr;
1380  SI.setOperand(1, TrueSI->getTrueValue());
1381  return &SI;
1382  }
1383  // select(C0, select(C1, a, b), b) -> select(C0&C1, a, b)
1384  // We choose this as normal form to enable folding on the And and shortening
1385  // paths for the values (this helps GetUnderlyingObjects() for example).
1386  if (TrueSI->getFalseValue() == FalseVal && TrueSI->hasOneUse()) {
1387  Value *And = Builder->CreateAnd(CondVal, TrueSI->getCondition());
1388  SI.setOperand(0, And);
1389  SI.setOperand(1, TrueSI->getTrueValue());
1390  return &SI;
1391  }
1392  }
1393  }
1394  if (SelectInst *FalseSI = dyn_cast<SelectInst>(FalseVal)) {
1395  if (FalseSI->getCondition()->getType() == CondVal->getType()) {
1396  // select(C, a, select(C, b, c)) -> select(C, a, c)
1397  if (FalseSI->getCondition() == CondVal) {
1398  if (SI.getFalseValue() == FalseSI->getFalseValue())
1399  return nullptr;
1400  SI.setOperand(2, FalseSI->getFalseValue());
1401  return &SI;
1402  }
1403  // select(C0, a, select(C1, a, b)) -> select(C0|C1, a, b)
1404  if (FalseSI->getTrueValue() == TrueVal && FalseSI->hasOneUse()) {
1405  Value *Or = Builder->CreateOr(CondVal, FalseSI->getCondition());
1406  SI.setOperand(0, Or);
1407  SI.setOperand(2, FalseSI->getFalseValue());
1408  return &SI;
1409  }
1410  }
1411  }
1412 
1413  if (BinaryOperator::isNot(CondVal)) {
1415  SI.setOperand(1, FalseVal);
1416  SI.setOperand(2, TrueVal);
1417  return &SI;
1418  }
1419 
1420  if (VectorType *VecTy = dyn_cast<VectorType>(SelType)) {
1421  unsigned VWidth = VecTy->getNumElements();
1422  APInt UndefElts(VWidth, 0);
1423  APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
1424  if (Value *V = SimplifyDemandedVectorElts(&SI, AllOnesEltMask, UndefElts)) {
1425  if (V != &SI)
1426  return replaceInstUsesWith(SI, V);
1427  return &SI;
1428  }
1429 
1430  if (isa<ConstantAggregateZero>(CondVal)) {
1431  return replaceInstUsesWith(SI, FalseVal);
1432  }
1433  }
1434 
1435  // See if we can determine the result of this select based on a dominating
1436  // condition.
1437  BasicBlock *Parent = SI.getParent();
1438  if (BasicBlock *Dom = Parent->getSinglePredecessor()) {
1439  auto *PBI = dyn_cast_or_null<BranchInst>(Dom->getTerminator());
1440  if (PBI && PBI->isConditional() &&
1441  PBI->getSuccessor(0) != PBI->getSuccessor(1) &&
1442  (PBI->getSuccessor(0) == Parent || PBI->getSuccessor(1) == Parent)) {
1443  bool CondIsFalse = PBI->getSuccessor(1) == Parent;
1444  Optional<bool> Implication = isImpliedCondition(
1445  PBI->getCondition(), SI.getCondition(), DL, CondIsFalse);
1446  if (Implication) {
1447  Value *V = *Implication ? TrueVal : FalseVal;
1448  return replaceInstUsesWith(SI, V);
1449  }
1450  }
1451  }
1452 
1453  if (Instruction *BitCastSel = foldSelectCmpBitcasts(SI, *Builder))
1454  return BitCastSel;
1455 
1456  return nullptr;
1457 }
BinaryOp_match< LHS, RHS, Instruction::And > m_And(const LHS &L, const RHS &R)
Definition: PatternMatch.h:506
class_match< Value > m_Value()
Match an arbitrary value and ignore it.
Definition: PatternMatch.h:64
Value * CreateICmp(CmpInst::Predicate P, Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1554
static APInt getSignBit(unsigned BitWidth)
Get the SignBit for a specific bit width.
Definition: APInt.h:451
void setFastMathFlags(FastMathFlags FMF)
Convenience function for setting multiple fast-math flags on this instruction, which must be an opera...
static bool IsFreeToInvert(Value *V, bool WillInvertAllUses)
Return true if the specified value is free to invert (apply ~ to).
class_match< CmpInst > m_Cmp()
Matches any compare instruction and ignore it.
Definition: PatternMatch.h:72
static APInt getAllOnesValue(unsigned numBits)
Get the all-ones value.
Definition: APInt.h:458
DiagnosticInfoOptimizationBase::Argument NV
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:1309
size_t i
Value * CreateICmpULT(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1478
Value * CreateXor(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1019
match_zero m_Zero()
Match an arbitrary zero/null constant.
Definition: PatternMatch.h:137
bool hasNUses(unsigned N) const
Return true if this Value has exactly N users.
Definition: Value.cpp:99
unsigned getBitWidth() const
getBitWidth - Return the bitwidth of this constant.
Definition: Constants.h:148
This class represents zero extension of integer types.
unsigned getNumOperands() const
Definition: User.h:167
bool isOneValue() const
Returns true if the value is one.
Definition: Constants.cpp:127
Value * CreateICmpSLT(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1490
class_match< Constant > m_Constant()
Match an arbitrary Constant and ignore it.
Definition: PatternMatch.h:83
unsigned less than
Definition: InstrTypes.h:905
0 1 0 0 True if ordered and less than
Definition: InstrTypes.h:886
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)
1 1 1 0 True if unordered or not equal
Definition: InstrTypes.h:896
static CastInst * CreateBitOrPointerCast(Value *S, Type *Ty, const Twine &Name="", Instruction *InsertBefore=nullptr)
Create a BitCast, a PtrToInt, or an IntToPTr cast instruction.
static bool isEquality(Predicate P)
Return true if this predicate is either EQ or NE.
FastMathFlags getFastMathFlags() const
Convenience function for getting all the fast-math flags, which must be an operator which supports th...
This class represents a sign extension of integer types.
void reserve(size_type N)
Definition: SmallVector.h:377
bool Ordered
Only applicable if Flavor is SPF_FMINNUM or SPF_FMAXNUM.
Signed maximum.
static Constant * getNullValue(Type *Ty)
Constructor to create a '0' constant of arbitrary type.
Definition: Constants.cpp:195
StringRef getName() const
Return a constant reference to the value's name.
Definition: Value.cpp:191
Value * CreateNot(Value *V, const Twine &Name="")
Definition: IRBuilder.h:1066
bool isCast() const
Definition: Instruction.h:117
void copyIRFlags(const Value *V)
Convenience method to copy supported wrapping, exact, and fast-math flags from V to this instruction...
bool match(Val *V, const Pattern &P)
Definition: PatternMatch.h:41
BinaryOp_match< LHS, RHS, Instruction::Xor > m_Xor(const LHS &L, const RHS &R)
Definition: PatternMatch.h:518
This class represents the LLVM 'select' instruction.
struct fuzzer::@269 Flags
Absolute value.
const APInt & getValue() const
Return the constant as an APInt value reference.
Definition: Constants.h:143
static GCRegistry::Add< StatepointGC > D("statepoint-example","an example strategy for statepoint")
CastClass_match< OpTy, Instruction::Trunc > m_Trunc(const OpTy &Op)
Matches Trunc.
Definition: PatternMatch.h:801
static Constant * get(ArrayRef< Constant * > V)
Definition: Constants.cpp:994
This provides a uniform API for creating instructions and inserting them into a basic block: either a...
Definition: IRBuilder.h:588
static Constant * getSExt(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1573
Value * CreateAdd(Value *LHS, Value *RHS, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:813
static SelectPatternFlavor getInverseMinMaxSelectPattern(SelectPatternFlavor SPF)
Instruction * clone() const
Create a copy of 'this' instruction that is identical in all ways except the following: ...
not_match< LHS > m_Not(const LHS &L)
Definition: PatternMatch.h:854
static Constant * getZExt(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1587
CastClass_match< OpTy, Instruction::ZExt > m_ZExt(const OpTy &Op)
Matches ZExt.
Definition: PatternMatch.h:813
This instruction compares its operands according to the predicate given to the constructor.
bool sgt(const APInt &RHS) const
Signed greather than comparison.
Definition: APInt.h:1101
InstTy * Insert(InstTy *I, const Twine &Name="") const
Insert and return the specified instruction.
Definition: IRBuilder.h:639
class_match< ConstantInt > m_ConstantInt()
Match an arbitrary ConstantInt and ignore it.
Definition: PatternMatch.h:75
static GCRegistry::Add< OcamlGC > B("ocaml","ocaml 3.10-compatible GC")
cst_pred_ty< is_power2 > m_Power2()
Match an integer or vector power of 2.
Definition: PatternMatch.h:272
void takeName(Value *V)
Transfer the name from V to this value.
Definition: Value.cpp:263
Type * getScalarType() const LLVM_READONLY
If this is a vector type, return the element type, otherwise return 'this'.
Definition: Type.cpp:44
static BinaryOperator * CreateAdd(Value *S1, Value *S2, const Twine &Name, Instruction *InsertBefore, Value *FlagsOp)
static const Value * getNotArgument(const Value *BinOp)
bool ult(const APInt &RHS) const
Unsigned less than comparison.
Definition: APInt.cpp:501
void replaceUsesOfWith(Value *From, Value *To)
Replace uses of one Value with another.
Definition: User.cpp:24
SelectPatternResult matchSelectPattern(Value *V, Value *&LHS, Value *&RHS, Instruction::CastOps *CastOp=nullptr)
Pattern match integer [SU]MIN, [SU]MAX and ABS idioms, returning the kind and providing the out param...
Value * CreateOr(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1003
Value * CreateFCmp(CmpInst::Predicate P, Value *LHS, Value *RHS, const Twine &Name="", MDNode *FPMathTag=nullptr)
Definition: IRBuilder.h:1561
bool isIntOrIntVectorTy() const
Return true if this is an integer type or a vector of integer types.
Definition: Type.h:201
apint_match m_APInt(const APInt *&Res)
Match a ConstantInt or splatted ConstantVector, binding the specified pointer to the contained APInt...
Definition: PatternMatch.h:180
Value * CreateAShr(Value *LHS, Value *RHS, const Twine &Name="", bool isExact=false)
Definition: IRBuilder.h:969
LLVM Basic Block Representation.
Definition: BasicBlock.h:51
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:45
BinaryOp_match< LHS, RHS, Instruction::Or > m_Or(const LHS &L, const RHS &R)
Definition: PatternMatch.h:512
bool isVectorTy() const
True if this is an instance of VectorType.
Definition: Type.h:219
bool sge(const APInt &RHS) const
Signed greather or equal comparison.
Definition: APInt.h:1135
bool isEquality() const
Return true if this predicate is either EQ or NE.
CastClass_match< OpTy, Instruction::BitCast > m_BitCast(const OpTy &Op)
Matches BitCast.
Definition: PatternMatch.h:789
This is an important base class in LLVM.
Definition: Constant.h:42
const Value * getCondition() const
Value * CreateSelect(Value *C, Value *True, Value *False, const Twine &Name="", Instruction *MDFrom=nullptr)
Definition: IRBuilder.h:1609
APInt Or(const APInt &LHS, const APInt &RHS)
Bitwise OR function for APInt.
Definition: APInt.h:1947
ConstantFP - Floating Point Values [float, double].
Definition: Constants.h:269
APInt Xor(const APInt &LHS, const APInt &RHS)
Bitwise XOR function for APInt.
Definition: APInt.h:1952
cst_pred_ty< is_all_ones > m_AllOnes()
Match an integer or vector with all bits set to true.
Definition: PatternMatch.h:252
bool isIntPredicate() const
Definition: InstrTypes.h:978
specificval_ty m_Specific(const Value *V)
Match if we have a specific specified value.
Definition: PatternMatch.h:322
bool sle(const APInt &RHS) const
Signed less or equal comparison.
Definition: APInt.h:1067
uint32_t Offset
Value * CreateNeg(Value *V, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:1044
static GCMetadataPrinterRegistry::Add< ErlangGCPrinter > X("erlang","erlang-compatible garbage collector")
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:880
bool uge(const APInt &RHS) const
Unsigned greater or equal comparison.
Definition: APInt.h:1119
Value * getOperand(unsigned i) const
Definition: User.h:145
bool isCommutative() const
Return true if the instruction is commutative:
Definition: Instruction.h:385
static bool isNot(const Value *V)
static Value * foldSelectICmpAndOr(const SelectInst &SI, 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...
Class to represent integer types.
Definition: DerivedTypes.h:39
Predicate getPredicate() const
Return the predicate for this instruction.
Definition: InstrTypes.h:960
Optional< bool > isImpliedCondition(const Value *LHS, const Value *RHS, const DataLayout &DL, bool InvertAPred=false, unsigned Depth=0, AssumptionCache *AC=nullptr, const Instruction *CxtI=nullptr, const DominatorTree *DT=nullptr)
Return true if RHS is known to be implied true by LHS.
Constant * getAggregateElement(unsigned Elt) const
For aggregates (struct/array/vector) return the constant that corresponds to the specified element if...
Definition: Constants.cpp:265
static Constant * getAllOnesValue(Type *Ty)
Get the all ones value.
Definition: Constants.cpp:249
Value * SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal, const DataLayout &DL, const TargetLibraryInfo *TLI=nullptr, const DominatorTree *DT=nullptr, AssumptionCache *AC=nullptr, const Instruction *CxtI=nullptr)
Given operands for a SelectInst, fold the result or return null.
static UndefValue * get(Type *T)
Static factory methods - Return an 'undef' object of the specified type.
Definition: Constants.cpp:1337
LLVMContext & getContext() const
Definition: IRBuilder.h:123
LLVMContext & getContext() const
All values hold a context through their type.
Definition: Value.cpp:654
bool isFPOrFPVectorTy() const
Return true if this is a FP type or a vector of FP.
Definition: Type.h:183
const Value * getTrueValue() const
bool isPowerOf2() const
Check if this APInt's value is a power of two greater than zero.
Definition: APInt.h:391
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:907
CastClass_match< OpTy, Instruction::SExt > m_SExt(const OpTy &Op)
Matches SExt.
Definition: PatternMatch.h:807
Floating point maxnum.
bool ugt(const APInt &RHS) const
Unsigned greather than comparison.
Definition: APInt.h:1083
0 0 1 0 True if ordered and greater than
Definition: InstrTypes.h:884
BinaryOps getOpcode() const
Definition: InstrTypes.h:541
This is the shared class of boolean and integer constants.
Definition: Constants.h:88
SelectPatternFlavor Flavor
bool slt(const APInt &RHS) const
Signed less than comparison.
Definition: APInt.cpp:533
unsigned getScalarSizeInBits() const LLVM_READONLY
If this is a vector type, return the getPrimitiveSizeInBits value for the element type...
Definition: Type.cpp:123
static Value * generateMinMaxSelectPattern(InstCombiner::BuilderTy *Builder, SelectPatternFlavor SPF, Value *A, Value *B)
unsigned logBase2() const
Definition: APInt.h:1507
Unsigned maximum.
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:843
1 1 0 0 True if unordered or less than
Definition: InstrTypes.h:894
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:230
SelectPatternFlavor
Specific patterns of select instructions we can match.
Floating point minnum.
signed less than
Definition: InstrTypes.h:909
Predicate getSwappedPredicate() const
For example, EQ->EQ, SLE->SGE, ULT->UGT, OEQ->OEQ, ULE->UGE, OLT->OGT, etc.
Definition: InstrTypes.h:1000
static Constant * getTrunc(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1559
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:558
bool isZero() const
This is just a convenience method to make client code smaller for a common code.
Definition: Constants.h:198
bool isNullValue() const
Return true if this is the value that would be returned by getNullValue.
Definition: Constants.cpp:90
static ConstantInt * getTrue(LLVMContext &Context)
Definition: Constants.cpp:506
Instruction * visitSelectInst(SelectInst &SI)
void setPredicate(Predicate P)
Set the predicate for this instruction to the specified value.
Definition: InstrTypes.h:965
static GCRegistry::Add< ShadowStackGC > C("shadow-stack","Very portable GC for uncooperative code generators")
void setOperand(unsigned i, Value *Val)
Definition: User.h:150
bool isAllOnesValue() const
Return true if this is the value that would be returned by getAllOnesValue.
Definition: Constants.cpp:105
void swap(llvm::BitVector &LHS, llvm::BitVector &RHS)
Implement std::swap in terms of BitVector swap.
Definition: BitVector.h:586
Value * getArgOperand(unsigned i) const
getArgOperand/setArgOperand - Return/set the i-th call argument.
Class to represent vector types.
Definition: DerivedTypes.h:369
Class for arbitrary precision integers.
Definition: APInt.h:77
bool isIntegerTy() const
True if this is an instance of IntegerType.
Definition: Type.h:195
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.
BasicBlock * getSinglePredecessor()
Return the predecessor of this block if it has a single predecessor block.
Definition: BasicBlock.cpp:226
unsigned getVectorNumElements() const
Definition: DerivedTypes.h:438
static Constant * getCast(unsigned ops, Constant *C, Type *Ty, bool OnlyIfReduced=false)
Convenience function for getting a Cast operation.
Definition: Constants.cpp:1452
Value * CreateShl(Value *LHS, Value *RHS, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:932
APInt And(const APInt &LHS, const APInt &RHS)
Bitwise AND function for APInt.
Definition: APInt.h:1942
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's ...
static IntegerType * getInt32Ty(LLVMContext &C)
Definition: Type.cpp:169
static bool isMinOrMax(SelectPatternFlavor SPF)
When implementing this min/max pattern as fcmp; select, does the fcmp have to be ordered?
static bool isUnordered(Predicate predicate)
Determine if the predicate is an unordered operation.
#define I(x, y, z)
Definition: MD5.cpp:54
bool hasOneUse() const
Return true if there is exactly one user of this value.
Definition: Value.h:383
void setArgOperand(unsigned i, Value *v)
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:287
static volatile int Zero
1 0 1 0 True if unordered or greater than
Definition: InstrTypes.h:892
Signed minimum.
bool hasNUsesOrMore(unsigned N) const
Return true if this value has N users or more.
Definition: Value.cpp:107
Value * CreateAnd(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:987
static Constant * getSelectFoldableConstant(Instruction *I)
For the same transformation as the previous function, return the identity constant that goes into the...
const APFloat & getValueAPF() const
Definition: Constants.h:300
Value * CreateCast(Instruction::CastOps Op, Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1394
bool isUnsigned() const
Determine if this instruction is using an unsigned comparison.
Definition: InstrTypes.h:1033
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
user_iterator user_begin()
Definition: Value.h:346
unsigned getPrimitiveSizeInBits() const LLVM_READONLY
Return the basic size of this type if it is a primitive type.
Definition: Type.cpp:108
0 0 0 1 True if ordered and equal
Definition: InstrTypes.h:883
LLVM Value Representation.
Definition: Value.h:71
static CmpInst::Predicate getCmpPredicateForMinMax(SelectPatternFlavor SPF, bool Ordered=false)
This file provides internal interfaces used to implement the InstCombine.
unsigned getOpcode() const
Returns a member of one of the enums like Instruction::Add.
Definition: Instruction.h:111
static unsigned getSelectFoldableOperands(Instruction *I)
We want to turn code that looks like this: C = or A, B D = select cond, C, A into: C = select cond...
bool isZero() const
Definition: APFloat.h:1031
cst_pred_ty< is_one > m_One()
Match an integer 1 or a vector with all elements equal to 1.
Definition: PatternMatch.h:244
std::underlying_type< E >::type Mask()
Get a bitmask with 1s in all places up to the high-order bit of E'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:95
static bool isSelect01(Constant *C1, Constant *C2)
Value * CreateLShr(Value *LHS, Value *RHS, const Twine &Name="", bool isExact=false)
Definition: IRBuilder.h:951
const Value * getFalseValue() const
Convenience struct for specifying and reasoning about fast-math flags.
Definition: Operator.h:168
unsigned greater than
Definition: InstrTypes.h:903
static GCMetadataPrinterRegistry::Add< OcamlGCMetadataPrinter > Y("ocaml","ocaml 3.10-compatible collector")
specific_intval m_SpecificInt(uint64_t V)
Match a specific integer value or vector with all elements equal to the value.
Definition: PatternMatch.h:383
static GCRegistry::Add< ErlangGC > A("erlang","erlang-compatible garbage collector")
bool ule(const APInt &RHS) const
Unsigned less or equal comparison.
Definition: APInt.h:1051
const BasicBlock * getParent() const
Definition: Instruction.h:62
Value * CreateFNeg(Value *V, const Twine &Name="", MDNode *FPMathTag=nullptr)
Definition: IRBuilder.h:1059
bool isOne() const
This is just a convenience method to make client code smaller for a common case.
Definition: Constants.h:206
bind_ty< Instruction > m_Instruction(Instruction *&I)
Match an instruction, capturing it if we match.
Definition: PatternMatch.h:300
IntegerType * Int32Ty
A wrapper class for inspecting calls to intrinsic functions.
Definition: IntrinsicInst.h:44