LLVM  6.0.0svn
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 
52  switch (SPF) {
53  default:
54  llvm_unreachable("unhandled!");
55 
56  case SPF_SMIN:
57  return SPF_SMAX;
58  case SPF_UMIN:
59  return SPF_UMAX;
60  case SPF_SMAX:
61  return SPF_SMIN;
62  case SPF_UMAX:
63  return SPF_UMIN;
64  }
65 }
66 
68  bool Ordered=false) {
69  switch (SPF) {
70  default:
71  llvm_unreachable("unhandled!");
72 
73  case SPF_SMIN:
74  return ICmpInst::ICMP_SLT;
75  case SPF_UMIN:
76  return ICmpInst::ICMP_ULT;
77  case SPF_SMAX:
78  return ICmpInst::ICMP_SGT;
79  case SPF_UMAX:
80  return ICmpInst::ICMP_UGT;
81  case SPF_FMINNUM:
82  return Ordered ? FCmpInst::FCMP_OLT : FCmpInst::FCMP_ULT;
83  case SPF_FMAXNUM:
84  return Ordered ? FCmpInst::FCMP_OGT : FCmpInst::FCMP_UGT;
85  }
86 }
87 
89  SelectPatternFlavor SPF, Value *A,
90  Value *B) {
93  return Builder.CreateSelect(Builder.CreateICmp(Pred, A, B), A, B);
94 }
95 
96 /// If one of the constants is zero (we know they can't both be) and we have an
97 /// icmp instruction with zero, and we have an 'and' with the non-constant value
98 /// and a power of two we can turn the select into a shift on the result of the
99 /// 'and'.
100 /// This folds:
101 /// select (icmp eq (and X, C1)), C2, C3
102 /// iff C1 is a power 2 and the difference between C2 and C3 is a power of 2.
103 /// To something like:
104 /// (shr (and (X, C1)), (log2(C1) - log2(C2-C3))) + C3
105 /// Or:
106 /// (shl (and (X, C1)), (log2(C2-C3) - log2(C1))) + C3
107 /// With some variations depending if C3 is larger than C2, or the shift
108 /// isn't needed, or the bit widths don't match.
109 static Value *foldSelectICmpAnd(Type *SelType, const ICmpInst *IC,
110  APInt TrueVal, APInt FalseVal,
111  InstCombiner::BuilderTy &Builder) {
112  assert(SelType->isIntOrIntVectorTy() && "Not an integer select?");
113 
114  // If this is a vector select, we need a vector compare.
115  if (SelType->isVectorTy() != IC->getType()->isVectorTy())
116  return nullptr;
117 
118  Value *V;
119  APInt AndMask;
120  bool CreateAnd = false;
121  ICmpInst::Predicate Pred = IC->getPredicate();
122  if (ICmpInst::isEquality(Pred)) {
123  if (!match(IC->getOperand(1), m_Zero()))
124  return nullptr;
125 
126  V = IC->getOperand(0);
127 
128  const APInt *AndRHS;
129  if (!match(V, m_And(m_Value(), m_Power2(AndRHS))))
130  return nullptr;
131 
132  AndMask = *AndRHS;
133  } else if (decomposeBitTestICmp(IC->getOperand(0), IC->getOperand(1),
134  Pred, V, AndMask)) {
135  assert(ICmpInst::isEquality(Pred) && "Not equality test?");
136 
137  if (!AndMask.isPowerOf2())
138  return nullptr;
139 
140  CreateAnd = true;
141  } else {
142  return nullptr;
143  }
144 
145  // If both select arms are non-zero see if we have a select of the form
146  // 'x ? 2^n + C : C'. Then we can offset both arms by C, use the logic
147  // for 'x ? 2^n : 0' and fix the thing up at the end.
148  APInt Offset(TrueVal.getBitWidth(), 0);
149  if (!TrueVal.isNullValue() && !FalseVal.isNullValue()) {
150  if ((TrueVal - FalseVal).isPowerOf2())
151  Offset = FalseVal;
152  else if ((FalseVal - TrueVal).isPowerOf2())
153  Offset = TrueVal;
154  else
155  return nullptr;
156 
157  // Adjust TrueVal and FalseVal to the offset.
158  TrueVal -= Offset;
159  FalseVal -= Offset;
160  }
161 
162  // Make sure one of the select arms is a power of 2.
163  if (!TrueVal.isPowerOf2() && !FalseVal.isPowerOf2())
164  return nullptr;
165 
166  // Determine which shift is needed to transform result of the 'and' into the
167  // desired result.
168  const APInt &ValC = !TrueVal.isNullValue() ? TrueVal : FalseVal;
169  unsigned ValZeros = ValC.logBase2();
170  unsigned AndZeros = AndMask.logBase2();
171 
172  if (CreateAnd) {
173  // Insert the AND instruction on the input to the truncate.
174  V = Builder.CreateAnd(V, ConstantInt::get(V->getType(), AndMask));
175  }
176 
177  // If types don't match we can still convert the select by introducing a zext
178  // or a trunc of the 'and'.
179  if (ValZeros > AndZeros) {
180  V = Builder.CreateZExtOrTrunc(V, SelType);
181  V = Builder.CreateShl(V, ValZeros - AndZeros);
182  } else if (ValZeros < AndZeros) {
183  V = Builder.CreateLShr(V, AndZeros - ValZeros);
184  V = Builder.CreateZExtOrTrunc(V, SelType);
185  } else
186  V = Builder.CreateZExtOrTrunc(V, SelType);
187 
188  // Okay, now we know that everything is set up, we just don't know whether we
189  // have a icmp_ne or icmp_eq and whether the true or false val is the zero.
190  bool ShouldNotVal = !TrueVal.isNullValue();
191  ShouldNotVal ^= Pred == ICmpInst::ICMP_NE;
192  if (ShouldNotVal)
193  V = Builder.CreateXor(V, ValC);
194 
195  // Apply an offset if needed.
196  if (!Offset.isNullValue())
197  V = Builder.CreateAdd(V, ConstantInt::get(V->getType(), Offset));
198  return V;
199 }
200 
201 /// We want to turn code that looks like this:
202 /// %C = or %A, %B
203 /// %D = select %cond, %C, %A
204 /// into:
205 /// %C = select %cond, %B, 0
206 /// %D = or %A, %C
207 ///
208 /// Assuming that the specified instruction is an operand to the select, return
209 /// a bitmask indicating which operands of this instruction are foldable if they
210 /// equal the other incoming value of the select.
212  switch (I->getOpcode()) {
213  case Instruction::Add:
214  case Instruction::Mul:
215  case Instruction::And:
216  case Instruction::Or:
217  case Instruction::Xor:
218  return 3; // Can fold through either operand.
219  case Instruction::Sub: // Can only fold on the amount subtracted.
220  case Instruction::Shl: // Can only fold on the shift amount.
221  case Instruction::LShr:
222  case Instruction::AShr:
223  return 1;
224  default:
225  return 0; // Cannot fold
226  }
227 }
228 
229 /// For the same transformation as the previous function, return the identity
230 /// constant that goes into the select.
232  switch (I->getOpcode()) {
233  default: llvm_unreachable("This cannot happen!");
234  case Instruction::Add:
235  case Instruction::Sub:
236  case Instruction::Or:
237  case Instruction::Xor:
238  case Instruction::Shl:
239  case Instruction::LShr:
240  case Instruction::AShr:
242  case Instruction::And:
244  case Instruction::Mul:
245  return APInt(I->getType()->getScalarSizeInBits(), 1);
246  }
247 }
248 
249 /// We have (select c, TI, FI), and we know that TI and FI have the same opcode.
250 Instruction *InstCombiner::foldSelectOpOp(SelectInst &SI, Instruction *TI,
251  Instruction *FI) {
252  // Don't break up min/max patterns. The hasOneUse checks below prevent that
253  // for most cases, but vector min/max with bitcasts can be transformed. If the
254  // one-use restrictions are eased for other patterns, we still don't want to
255  // obfuscate min/max.
256  if ((match(&SI, m_SMin(m_Value(), m_Value())) ||
257  match(&SI, m_SMax(m_Value(), m_Value())) ||
258  match(&SI, m_UMin(m_Value(), m_Value())) ||
259  match(&SI, m_UMax(m_Value(), m_Value()))))
260  return nullptr;
261 
262  // If this is a cast from the same type, merge.
263  if (TI->getNumOperands() == 1 && TI->isCast()) {
264  Type *FIOpndTy = FI->getOperand(0)->getType();
265  if (TI->getOperand(0)->getType() != FIOpndTy)
266  return nullptr;
267 
268  // The select condition may be a vector. We may only change the operand
269  // type if the vector width remains the same (and matches the condition).
270  Type *CondTy = SI.getCondition()->getType();
271  if (CondTy->isVectorTy()) {
272  if (!FIOpndTy->isVectorTy())
273  return nullptr;
274  if (CondTy->getVectorNumElements() != FIOpndTy->getVectorNumElements())
275  return nullptr;
276 
277  // TODO: If the backend knew how to deal with casts better, we could
278  // remove this limitation. For now, there's too much potential to create
279  // worse codegen by promoting the select ahead of size-altering casts
280  // (PR28160).
281  //
282  // Note that ValueTracking's matchSelectPattern() looks through casts
283  // without checking 'hasOneUse' when it matches min/max patterns, so this
284  // transform may end up happening anyway.
285  if (TI->getOpcode() != Instruction::BitCast &&
286  (!TI->hasOneUse() || !FI->hasOneUse()))
287  return nullptr;
288  } else if (!TI->hasOneUse() || !FI->hasOneUse()) {
289  // TODO: The one-use restrictions for a scalar select could be eased if
290  // the fold of a select in visitLoadInst() was enhanced to match a pattern
291  // that includes a cast.
292  return nullptr;
293  }
294 
295  // Fold this by inserting a select from the input values.
296  Value *NewSI =
297  Builder.CreateSelect(SI.getCondition(), TI->getOperand(0),
298  FI->getOperand(0), SI.getName() + ".v", &SI);
299  return CastInst::Create(Instruction::CastOps(TI->getOpcode()), NewSI,
300  TI->getType());
301  }
302 
303  // Only handle binary operators with one-use here. As with the cast case
304  // above, it may be possible to relax the one-use constraint, but that needs
305  // be examined carefully since it may not reduce the total number of
306  // instructions.
308  if (!BO || !TI->hasOneUse() || !FI->hasOneUse())
309  return nullptr;
310 
311  // Figure out if the operations have any operands in common.
312  Value *MatchOp, *OtherOpT, *OtherOpF;
313  bool MatchIsOpZero;
314  if (TI->getOperand(0) == FI->getOperand(0)) {
315  MatchOp = TI->getOperand(0);
316  OtherOpT = TI->getOperand(1);
317  OtherOpF = FI->getOperand(1);
318  MatchIsOpZero = true;
319  } else if (TI->getOperand(1) == FI->getOperand(1)) {
320  MatchOp = TI->getOperand(1);
321  OtherOpT = TI->getOperand(0);
322  OtherOpF = FI->getOperand(0);
323  MatchIsOpZero = false;
324  } else if (!TI->isCommutative()) {
325  return nullptr;
326  } else if (TI->getOperand(0) == FI->getOperand(1)) {
327  MatchOp = TI->getOperand(0);
328  OtherOpT = TI->getOperand(1);
329  OtherOpF = FI->getOperand(0);
330  MatchIsOpZero = true;
331  } else if (TI->getOperand(1) == FI->getOperand(0)) {
332  MatchOp = TI->getOperand(1);
333  OtherOpT = TI->getOperand(0);
334  OtherOpF = FI->getOperand(1);
335  MatchIsOpZero = true;
336  } else {
337  return nullptr;
338  }
339 
340  // If we reach here, they do have operations in common.
341  Value *NewSI = Builder.CreateSelect(SI.getCondition(), OtherOpT, OtherOpF,
342  SI.getName() + ".v", &SI);
343  Value *Op0 = MatchIsOpZero ? MatchOp : NewSI;
344  Value *Op1 = MatchIsOpZero ? NewSI : MatchOp;
345  return BinaryOperator::Create(BO->getOpcode(), Op0, Op1);
346 }
347 
348 static bool isSelect01(const APInt &C1I, const APInt &C2I) {
349  if (!C1I.isNullValue() && !C2I.isNullValue()) // One side must be zero.
350  return false;
351  return C1I.isOneValue() || C1I.isAllOnesValue() ||
352  C2I.isOneValue() || C2I.isAllOnesValue();
353 }
354 
355 /// Try to fold the select into one of the operands to allow further
356 /// optimization.
357 Instruction *InstCombiner::foldSelectIntoOp(SelectInst &SI, Value *TrueVal,
358  Value *FalseVal) {
359  // See the comment above GetSelectFoldableOperands for a description of the
360  // transformation we are doing here.
361  if (auto *TVI = dyn_cast<BinaryOperator>(TrueVal)) {
362  if (TVI->hasOneUse() && !isa<Constant>(FalseVal)) {
363  if (unsigned SFO = getSelectFoldableOperands(TVI)) {
364  unsigned OpToFold = 0;
365  if ((SFO & 1) && FalseVal == TVI->getOperand(0)) {
366  OpToFold = 1;
367  } else if ((SFO & 2) && FalseVal == TVI->getOperand(1)) {
368  OpToFold = 2;
369  }
370 
371  if (OpToFold) {
373  Value *OOp = TVI->getOperand(2-OpToFold);
374  // Avoid creating select between 2 constants unless it's selecting
375  // between 0, 1 and -1.
376  const APInt *OOpC;
377  bool OOpIsAPInt = match(OOp, m_APInt(OOpC));
378  if (!isa<Constant>(OOp) || (OOpIsAPInt && isSelect01(CI, *OOpC))) {
379  Value *C = ConstantInt::get(OOp->getType(), CI);
380  Value *NewSel = Builder.CreateSelect(SI.getCondition(), OOp, C);
381  NewSel->takeName(TVI);
382  BinaryOperator *BO = BinaryOperator::Create(TVI->getOpcode(),
383  FalseVal, NewSel);
384  BO->copyIRFlags(TVI);
385  return BO;
386  }
387  }
388  }
389  }
390  }
391 
392  if (auto *FVI = dyn_cast<BinaryOperator>(FalseVal)) {
393  if (FVI->hasOneUse() && !isa<Constant>(TrueVal)) {
394  if (unsigned SFO = getSelectFoldableOperands(FVI)) {
395  unsigned OpToFold = 0;
396  if ((SFO & 1) && TrueVal == FVI->getOperand(0)) {
397  OpToFold = 1;
398  } else if ((SFO & 2) && TrueVal == FVI->getOperand(1)) {
399  OpToFold = 2;
400  }
401 
402  if (OpToFold) {
404  Value *OOp = FVI->getOperand(2-OpToFold);
405  // Avoid creating select between 2 constants unless it's selecting
406  // between 0, 1 and -1.
407  const APInt *OOpC;
408  bool OOpIsAPInt = match(OOp, m_APInt(OOpC));
409  if (!isa<Constant>(OOp) || (OOpIsAPInt && isSelect01(CI, *OOpC))) {
410  Value *C = ConstantInt::get(OOp->getType(), CI);
411  Value *NewSel = Builder.CreateSelect(SI.getCondition(), C, OOp);
412  NewSel->takeName(FVI);
413  BinaryOperator *BO = BinaryOperator::Create(FVI->getOpcode(),
414  TrueVal, NewSel);
415  BO->copyIRFlags(FVI);
416  return BO;
417  }
418  }
419  }
420  }
421  }
422 
423  return nullptr;
424 }
425 
426 /// We want to turn:
427 /// (select (icmp eq (and X, C1), 0), Y, (or Y, C2))
428 /// into:
429 /// (or (shl (and X, C1), C3), Y)
430 /// iff:
431 /// C1 and C2 are both powers of 2
432 /// where:
433 /// C3 = Log(C2) - Log(C1)
434 ///
435 /// This transform handles cases where:
436 /// 1. The icmp predicate is inverted
437 /// 2. The select operands are reversed
438 /// 3. The magnitude of C2 and C1 are flipped
439 static Value *foldSelectICmpAndOr(const ICmpInst *IC, Value *TrueVal,
440  Value *FalseVal,
441  InstCombiner::BuilderTy &Builder) {
442  // Only handle integer compares. Also, if this is a vector select, we need a
443  // vector compare.
444  if (!TrueVal->getType()->isIntOrIntVectorTy() ||
445  TrueVal->getType()->isVectorTy() != IC->getType()->isVectorTy())
446  return nullptr;
447 
448  Value *CmpLHS = IC->getOperand(0);
449  Value *CmpRHS = IC->getOperand(1);
450 
451  Value *V;
452  unsigned C1Log;
453  bool IsEqualZero;
454  bool NeedAnd = false;
455  if (IC->isEquality()) {
456  if (!match(CmpRHS, m_Zero()))
457  return nullptr;
458 
459  const APInt *C1;
460  if (!match(CmpLHS, m_And(m_Value(), m_Power2(C1))))
461  return nullptr;
462 
463  V = CmpLHS;
464  C1Log = C1->logBase2();
465  IsEqualZero = IC->getPredicate() == ICmpInst::ICMP_EQ;
466  } else if (IC->getPredicate() == ICmpInst::ICMP_SLT ||
467  IC->getPredicate() == ICmpInst::ICMP_SGT) {
468  // We also need to recognize (icmp slt (trunc (X)), 0) and
469  // (icmp sgt (trunc (X)), -1).
470  IsEqualZero = IC->getPredicate() == ICmpInst::ICMP_SGT;
471  if ((IsEqualZero && !match(CmpRHS, m_AllOnes())) ||
472  (!IsEqualZero && !match(CmpRHS, m_Zero())))
473  return nullptr;
474 
475  if (!match(CmpLHS, m_OneUse(m_Trunc(m_Value(V)))))
476  return nullptr;
477 
478  C1Log = CmpLHS->getType()->getScalarSizeInBits() - 1;
479  NeedAnd = true;
480  } else {
481  return nullptr;
482  }
483 
484  const APInt *C2;
485  bool OrOnTrueVal = false;
486  bool OrOnFalseVal = match(FalseVal, m_Or(m_Specific(TrueVal), m_Power2(C2)));
487  if (!OrOnFalseVal)
488  OrOnTrueVal = match(TrueVal, m_Or(m_Specific(FalseVal), m_Power2(C2)));
489 
490  if (!OrOnFalseVal && !OrOnTrueVal)
491  return nullptr;
492 
493  Value *Y = OrOnFalseVal ? TrueVal : FalseVal;
494 
495  unsigned C2Log = C2->logBase2();
496 
497  bool NeedXor = (!IsEqualZero && OrOnFalseVal) || (IsEqualZero && OrOnTrueVal);
498  bool NeedShift = C1Log != C2Log;
499  bool NeedZExtTrunc = Y->getType()->getScalarSizeInBits() !=
501 
502  // Make sure we don't create more instructions than we save.
503  Value *Or = OrOnFalseVal ? FalseVal : TrueVal;
504  if ((NeedShift + NeedXor + NeedZExtTrunc) >
505  (IC->hasOneUse() + Or->hasOneUse()))
506  return nullptr;
507 
508  if (NeedAnd) {
509  // Insert the AND instruction on the input to the truncate.
511  V = Builder.CreateAnd(V, ConstantInt::get(V->getType(), C1));
512  }
513 
514  if (C2Log > C1Log) {
515  V = Builder.CreateZExtOrTrunc(V, Y->getType());
516  V = Builder.CreateShl(V, C2Log - C1Log);
517  } else if (C1Log > C2Log) {
518  V = Builder.CreateLShr(V, C1Log - C2Log);
519  V = Builder.CreateZExtOrTrunc(V, Y->getType());
520  } else
521  V = Builder.CreateZExtOrTrunc(V, Y->getType());
522 
523  if (NeedXor)
524  V = Builder.CreateXor(V, *C2);
525 
526  return Builder.CreateOr(V, Y);
527 }
528 
529 /// Attempt to fold a cttz/ctlz followed by a icmp plus select into a single
530 /// call to cttz/ctlz with flag 'is_zero_undef' cleared.
531 ///
532 /// For example, we can fold the following code sequence:
533 /// \code
534 /// %0 = tail call i32 @llvm.cttz.i32(i32 %x, i1 true)
535 /// %1 = icmp ne i32 %x, 0
536 /// %2 = select i1 %1, i32 %0, i32 32
537 /// \code
538 ///
539 /// into:
540 /// %0 = tail call i32 @llvm.cttz.i32(i32 %x, i1 false)
541 static Value *foldSelectCttzCtlz(ICmpInst *ICI, Value *TrueVal, Value *FalseVal,
542  InstCombiner::BuilderTy &Builder) {
543  ICmpInst::Predicate Pred = ICI->getPredicate();
544  Value *CmpLHS = ICI->getOperand(0);
545  Value *CmpRHS = ICI->getOperand(1);
546 
547  // Check if the condition value compares a value for equality against zero.
548  if (!ICI->isEquality() || !match(CmpRHS, m_Zero()))
549  return nullptr;
550 
551  Value *Count = FalseVal;
552  Value *ValueOnZero = TrueVal;
553  if (Pred == ICmpInst::ICMP_NE)
554  std::swap(Count, ValueOnZero);
555 
556  // Skip zero extend/truncate.
557  Value *V = nullptr;
558  if (match(Count, m_ZExt(m_Value(V))) ||
559  match(Count, m_Trunc(m_Value(V))))
560  Count = V;
561 
562  // Check if the value propagated on zero is a constant number equal to the
563  // sizeof in bits of 'Count'.
564  unsigned SizeOfInBits = Count->getType()->getScalarSizeInBits();
565  if (!match(ValueOnZero, m_SpecificInt(SizeOfInBits)))
566  return nullptr;
567 
568  // Check that 'Count' is a call to intrinsic cttz/ctlz. Also check that the
569  // input to the cttz/ctlz is used as LHS for the compare instruction.
570  if (match(Count, m_Intrinsic<Intrinsic::cttz>(m_Specific(CmpLHS))) ||
571  match(Count, m_Intrinsic<Intrinsic::ctlz>(m_Specific(CmpLHS)))) {
572  IntrinsicInst *II = cast<IntrinsicInst>(Count);
573  // Explicitly clear the 'undef_on_zero' flag.
574  IntrinsicInst *NewI = cast<IntrinsicInst>(II->clone());
575  NewI->setArgOperand(1, ConstantInt::getFalse(NewI->getContext()));
576  Builder.Insert(NewI);
577  return Builder.CreateZExtOrTrunc(NewI, ValueOnZero->getType());
578  }
579 
580  return nullptr;
581 }
582 
583 /// Return true if we find and adjust an icmp+select pattern where the compare
584 /// is with a constant that can be incremented or decremented to match the
585 /// minimum or maximum idiom.
586 static bool adjustMinMax(SelectInst &Sel, ICmpInst &Cmp) {
587  ICmpInst::Predicate Pred = Cmp.getPredicate();
588  Value *CmpLHS = Cmp.getOperand(0);
589  Value *CmpRHS = Cmp.getOperand(1);
590  Value *TrueVal = Sel.getTrueValue();
591  Value *FalseVal = Sel.getFalseValue();
592 
593  // We may move or edit the compare, so make sure the select is the only user.
594  const APInt *CmpC;
595  if (!Cmp.hasOneUse() || !match(CmpRHS, m_APInt(CmpC)))
596  return false;
597 
598  // These transforms only work for selects of integers or vector selects of
599  // integer vectors.
600  Type *SelTy = Sel.getType();
601  auto *SelEltTy = dyn_cast<IntegerType>(SelTy->getScalarType());
602  if (!SelEltTy || SelTy->isVectorTy() != Cmp.getType()->isVectorTy())
603  return false;
604 
605  Constant *AdjustedRHS;
606  if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_SGT)
607  AdjustedRHS = ConstantInt::get(CmpRHS->getType(), *CmpC + 1);
608  else if (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_SLT)
609  AdjustedRHS = ConstantInt::get(CmpRHS->getType(), *CmpC - 1);
610  else
611  return false;
612 
613  // X > C ? X : C+1 --> X < C+1 ? C+1 : X
614  // X < C ? X : C-1 --> X > C-1 ? C-1 : X
615  if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) ||
616  (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) {
617  ; // Nothing to do here. Values match without any sign/zero extension.
618  }
619  // Types do not match. Instead of calculating this with mixed types, promote
620  // all to the larger type. This enables scalar evolution to analyze this
621  // expression.
622  else if (CmpRHS->getType()->getScalarSizeInBits() < SelEltTy->getBitWidth()) {
623  Constant *SextRHS = ConstantExpr::getSExt(AdjustedRHS, SelTy);
624 
625  // X = sext x; x >s c ? X : C+1 --> X = sext x; X <s C+1 ? C+1 : X
626  // X = sext x; x <s c ? X : C-1 --> X = sext x; X >s C-1 ? C-1 : X
627  // X = sext x; x >u c ? X : C+1 --> X = sext x; X <u C+1 ? C+1 : X
628  // X = sext x; x <u c ? X : C-1 --> X = sext x; X >u C-1 ? C-1 : X
629  if (match(TrueVal, m_SExt(m_Specific(CmpLHS))) && SextRHS == FalseVal) {
630  CmpLHS = TrueVal;
631  AdjustedRHS = SextRHS;
632  } else if (match(FalseVal, m_SExt(m_Specific(CmpLHS))) &&
633  SextRHS == TrueVal) {
634  CmpLHS = FalseVal;
635  AdjustedRHS = SextRHS;
636  } else if (Cmp.isUnsigned()) {
637  Constant *ZextRHS = ConstantExpr::getZExt(AdjustedRHS, SelTy);
638  // X = zext x; x >u c ? X : C+1 --> X = zext x; X <u C+1 ? C+1 : X
639  // X = zext x; x <u c ? X : C-1 --> X = zext x; X >u C-1 ? C-1 : X
640  // zext + signed compare cannot be changed:
641  // 0xff <s 0x00, but 0x00ff >s 0x0000
642  if (match(TrueVal, m_ZExt(m_Specific(CmpLHS))) && ZextRHS == FalseVal) {
643  CmpLHS = TrueVal;
644  AdjustedRHS = ZextRHS;
645  } else if (match(FalseVal, m_ZExt(m_Specific(CmpLHS))) &&
646  ZextRHS == TrueVal) {
647  CmpLHS = FalseVal;
648  AdjustedRHS = ZextRHS;
649  } else {
650  return false;
651  }
652  } else {
653  return false;
654  }
655  } else {
656  return false;
657  }
658 
659  Pred = ICmpInst::getSwappedPredicate(Pred);
660  CmpRHS = AdjustedRHS;
661  std::swap(FalseVal, TrueVal);
662  Cmp.setPredicate(Pred);
663  Cmp.setOperand(0, CmpLHS);
664  Cmp.setOperand(1, CmpRHS);
665  Sel.setOperand(1, TrueVal);
666  Sel.setOperand(2, FalseVal);
667  Sel.swapProfMetadata();
668 
669  // Move the compare instruction right before the select instruction. Otherwise
670  // the sext/zext value may be defined after the compare instruction uses it.
671  Cmp.moveBefore(&Sel);
672 
673  return true;
674 }
675 
676 /// If this is an integer min/max (icmp + select) with a constant operand,
677 /// create the canonical icmp for the min/max operation and canonicalize the
678 /// constant to the 'false' operand of the select:
679 /// select (icmp Pred X, C1), C2, X --> select (icmp Pred' X, C2), X, C2
680 /// Note: if C1 != C2, this will change the icmp constant to the existing
681 /// constant operand of the select.
682 static Instruction *
683 canonicalizeMinMaxWithConstant(SelectInst &Sel, ICmpInst &Cmp,
684  InstCombiner::BuilderTy &Builder) {
685  if (!Cmp.hasOneUse() || !isa<Constant>(Cmp.getOperand(1)))
686  return nullptr;
687 
688  // Canonicalize the compare predicate based on whether we have min or max.
689  Value *LHS, *RHS;
690  ICmpInst::Predicate NewPred;
691  SelectPatternResult SPR = matchSelectPattern(&Sel, LHS, RHS);
692  switch (SPR.Flavor) {
693  case SPF_SMIN: NewPred = ICmpInst::ICMP_SLT; break;
694  case SPF_UMIN: NewPred = ICmpInst::ICMP_ULT; break;
695  case SPF_SMAX: NewPred = ICmpInst::ICMP_SGT; break;
696  case SPF_UMAX: NewPred = ICmpInst::ICMP_UGT; break;
697  default: return nullptr;
698  }
699 
700  // Is this already canonical?
701  if (Cmp.getOperand(0) == LHS && Cmp.getOperand(1) == RHS &&
702  Cmp.getPredicate() == NewPred)
703  return nullptr;
704 
705  // Create the canonical compare and plug it into the select.
706  Sel.setCondition(Builder.CreateICmp(NewPred, LHS, RHS));
707 
708  // If the select operands did not change, we're done.
709  if (Sel.getTrueValue() == LHS && Sel.getFalseValue() == RHS)
710  return &Sel;
711 
712  // If we are swapping the select operands, swap the metadata too.
713  assert(Sel.getTrueValue() == RHS && Sel.getFalseValue() == LHS &&
714  "Unexpected results from matchSelectPattern");
715  Sel.setTrueValue(LHS);
716  Sel.setFalseValue(RHS);
717  Sel.swapProfMetadata();
718  return &Sel;
719 }
720 
721 /// Visit a SelectInst that has an ICmpInst as its first operand.
722 Instruction *InstCombiner::foldSelectInstWithICmp(SelectInst &SI,
723  ICmpInst *ICI) {
724  Value *TrueVal = SI.getTrueValue();
725  Value *FalseVal = SI.getFalseValue();
726 
727  if (Instruction *NewSel = canonicalizeMinMaxWithConstant(SI, *ICI, Builder))
728  return NewSel;
729 
730  bool Changed = adjustMinMax(SI, *ICI);
731 
732  ICmpInst::Predicate Pred = ICI->getPredicate();
733  Value *CmpLHS = ICI->getOperand(0);
734  Value *CmpRHS = ICI->getOperand(1);
735 
736  // Transform (X >s -1) ? C1 : C2 --> ((X >>s 31) & (C2 - C1)) + C1
737  // and (X <s 0) ? C2 : C1 --> ((X >>s 31) & (C2 - C1)) + C1
738  // FIXME: Type and constness constraints could be lifted, but we have to
739  // watch code size carefully. We should consider xor instead of
740  // sub/add when we decide to do that.
741  // TODO: Merge this with foldSelectICmpAnd somehow.
742  if (CmpLHS->getType()->isIntOrIntVectorTy() &&
743  CmpLHS->getType() == TrueVal->getType()) {
744  const APInt *C1, *C2;
745  if (match(TrueVal, m_APInt(C1)) && match(FalseVal, m_APInt(C2))) {
746  ICmpInst::Predicate Pred = ICI->getPredicate();
747  Value *X;
748  APInt Mask;
749  if (decomposeBitTestICmp(CmpLHS, CmpRHS, Pred, X, Mask, false)) {
750  if (Mask.isSignMask()) {
751  assert(X == CmpLHS && "Expected to use the compare input directly");
752  assert(ICmpInst::isEquality(Pred) && "Expected equality predicate");
753 
754  if (Pred == ICmpInst::ICMP_NE)
755  std::swap(C1, C2);
756 
757  // This shift results in either -1 or 0.
758  Value *AShr = Builder.CreateAShr(X, Mask.getBitWidth() - 1);
759 
760  // Check if we can express the operation with a single or.
761  if (C2->isAllOnesValue())
762  return replaceInstUsesWith(SI, Builder.CreateOr(AShr, *C1));
763 
764  Value *And = Builder.CreateAnd(AShr, *C2 - *C1);
765  return replaceInstUsesWith(SI, Builder.CreateAdd(And,
766  ConstantInt::get(And->getType(), *C1)));
767  }
768  }
769  }
770  }
771 
772  {
773  const APInt *TrueValC, *FalseValC;
774  if (match(TrueVal, m_APInt(TrueValC)) &&
775  match(FalseVal, m_APInt(FalseValC)))
776  if (Value *V = foldSelectICmpAnd(SI.getType(), ICI, *TrueValC,
777  *FalseValC, Builder))
778  return replaceInstUsesWith(SI, V);
779  }
780 
781  // NOTE: if we wanted to, this is where to detect integer MIN/MAX
782 
783  if (CmpRHS != CmpLHS && isa<Constant>(CmpRHS)) {
784  if (CmpLHS == TrueVal && Pred == ICmpInst::ICMP_EQ) {
785  // Transform (X == C) ? X : Y -> (X == C) ? C : Y
786  SI.setOperand(1, CmpRHS);
787  Changed = true;
788  } else if (CmpLHS == FalseVal && Pred == ICmpInst::ICMP_NE) {
789  // Transform (X != C) ? Y : X -> (X != C) ? Y : C
790  SI.setOperand(2, CmpRHS);
791  Changed = true;
792  }
793  }
794 
795  // FIXME: This code is nearly duplicated in InstSimplify. Using/refactoring
796  // decomposeBitTestICmp() might help.
797  {
798  unsigned BitWidth =
799  DL.getTypeSizeInBits(TrueVal->getType()->getScalarType());
800  APInt MinSignedValue = APInt::getSignedMinValue(BitWidth);
801  Value *X;
802  const APInt *Y, *C;
803  bool TrueWhenUnset;
804  bool IsBitTest = false;
805  if (ICmpInst::isEquality(Pred) &&
806  match(CmpLHS, m_And(m_Value(X), m_Power2(Y))) &&
807  match(CmpRHS, m_Zero())) {
808  IsBitTest = true;
809  TrueWhenUnset = Pred == ICmpInst::ICMP_EQ;
810  } else if (Pred == ICmpInst::ICMP_SLT && match(CmpRHS, m_Zero())) {
811  X = CmpLHS;
812  Y = &MinSignedValue;
813  IsBitTest = true;
814  TrueWhenUnset = false;
815  } else if (Pred == ICmpInst::ICMP_SGT && match(CmpRHS, m_AllOnes())) {
816  X = CmpLHS;
817  Y = &MinSignedValue;
818  IsBitTest = true;
819  TrueWhenUnset = true;
820  }
821  if (IsBitTest) {
822  Value *V = nullptr;
823  // (X & Y) == 0 ? X : X ^ Y --> X & ~Y
824  if (TrueWhenUnset && TrueVal == X &&
825  match(FalseVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
826  V = Builder.CreateAnd(X, ~(*Y));
827  // (X & Y) != 0 ? X ^ Y : X --> X & ~Y
828  else if (!TrueWhenUnset && FalseVal == X &&
829  match(TrueVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
830  V = Builder.CreateAnd(X, ~(*Y));
831  // (X & Y) == 0 ? X ^ Y : X --> X | Y
832  else if (TrueWhenUnset && FalseVal == X &&
833  match(TrueVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
834  V = Builder.CreateOr(X, *Y);
835  // (X & Y) != 0 ? X : X ^ Y --> X | Y
836  else if (!TrueWhenUnset && TrueVal == X &&
837  match(FalseVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
838  V = Builder.CreateOr(X, *Y);
839 
840  if (V)
841  return replaceInstUsesWith(SI, V);
842  }
843  }
844 
845  if (Value *V = foldSelectICmpAndOr(ICI, TrueVal, FalseVal, Builder))
846  return replaceInstUsesWith(SI, V);
847 
848  if (Value *V = foldSelectCttzCtlz(ICI, TrueVal, FalseVal, Builder))
849  return replaceInstUsesWith(SI, V);
850 
851  return Changed ? &SI : nullptr;
852 }
853 
854 
855 /// SI is a select whose condition is a PHI node (but the two may be in
856 /// different blocks). See if the true/false values (V) are live in all of the
857 /// predecessor blocks of the PHI. For example, cases like this can't be mapped:
858 ///
859 /// X = phi [ C1, BB1], [C2, BB2]
860 /// Y = add
861 /// Z = select X, Y, 0
862 ///
863 /// because Y is not live in BB1/BB2.
864 static bool canSelectOperandBeMappingIntoPredBlock(const Value *V,
865  const SelectInst &SI) {
866  // If the value is a non-instruction value like a constant or argument, it
867  // can always be mapped.
868  const Instruction *I = dyn_cast<Instruction>(V);
869  if (!I) return true;
870 
871  // If V is a PHI node defined in the same block as the condition PHI, we can
872  // map the arguments.
873  const PHINode *CondPHI = cast<PHINode>(SI.getCondition());
874 
875  if (const PHINode *VP = dyn_cast<PHINode>(I))
876  if (VP->getParent() == CondPHI->getParent())
877  return true;
878 
879  // Otherwise, if the PHI and select are defined in the same block and if V is
880  // defined in a different block, then we can transform it.
881  if (SI.getParent() == CondPHI->getParent() &&
882  I->getParent() != CondPHI->getParent())
883  return true;
884 
885  // Otherwise we have a 'hard' case and we can't tell without doing more
886  // detailed dominator based analysis, punt.
887  return false;
888 }
889 
890 /// We have an SPF (e.g. a min or max) of an SPF of the form:
891 /// SPF2(SPF1(A, B), C)
892 Instruction *InstCombiner::foldSPFofSPF(Instruction *Inner,
893  SelectPatternFlavor SPF1,
894  Value *A, Value *B,
895  Instruction &Outer,
896  SelectPatternFlavor SPF2, Value *C) {
897  if (Outer.getType() != Inner->getType())
898  return nullptr;
899 
900  if (C == A || C == B) {
901  // MAX(MAX(A, B), B) -> MAX(A, B)
902  // MIN(MIN(a, b), a) -> MIN(a, b)
903  if (SPF1 == SPF2)
904  return replaceInstUsesWith(Outer, Inner);
905 
906  // MAX(MIN(a, b), a) -> a
907  // MIN(MAX(a, b), a) -> a
908  if ((SPF1 == SPF_SMIN && SPF2 == SPF_SMAX) ||
909  (SPF1 == SPF_SMAX && SPF2 == SPF_SMIN) ||
910  (SPF1 == SPF_UMIN && SPF2 == SPF_UMAX) ||
911  (SPF1 == SPF_UMAX && SPF2 == SPF_UMIN))
912  return replaceInstUsesWith(Outer, C);
913  }
914 
915  if (SPF1 == SPF2) {
916  const APInt *CB, *CC;
917  if (match(B, m_APInt(CB)) && match(C, m_APInt(CC))) {
918  // MIN(MIN(A, 23), 97) -> MIN(A, 23)
919  // MAX(MAX(A, 97), 23) -> MAX(A, 97)
920  if ((SPF1 == SPF_UMIN && CB->ule(*CC)) ||
921  (SPF1 == SPF_SMIN && CB->sle(*CC)) ||
922  (SPF1 == SPF_UMAX && CB->uge(*CC)) ||
923  (SPF1 == SPF_SMAX && CB->sge(*CC)))
924  return replaceInstUsesWith(Outer, Inner);
925 
926  // MIN(MIN(A, 97), 23) -> MIN(A, 23)
927  // MAX(MAX(A, 23), 97) -> MAX(A, 97)
928  if ((SPF1 == SPF_UMIN && CB->ugt(*CC)) ||
929  (SPF1 == SPF_SMIN && CB->sgt(*CC)) ||
930  (SPF1 == SPF_UMAX && CB->ult(*CC)) ||
931  (SPF1 == SPF_SMAX && CB->slt(*CC))) {
932  Outer.replaceUsesOfWith(Inner, A);
933  return &Outer;
934  }
935  }
936  }
937 
938  // ABS(ABS(X)) -> ABS(X)
939  // NABS(NABS(X)) -> NABS(X)
940  if (SPF1 == SPF2 && (SPF1 == SPF_ABS || SPF1 == SPF_NABS)) {
941  return replaceInstUsesWith(Outer, Inner);
942  }
943 
944  // ABS(NABS(X)) -> ABS(X)
945  // NABS(ABS(X)) -> NABS(X)
946  if ((SPF1 == SPF_ABS && SPF2 == SPF_NABS) ||
947  (SPF1 == SPF_NABS && SPF2 == SPF_ABS)) {
948  SelectInst *SI = cast<SelectInst>(Inner);
949  Value *NewSI =
950  Builder.CreateSelect(SI->getCondition(), SI->getFalseValue(),
951  SI->getTrueValue(), SI->getName(), SI);
952  return replaceInstUsesWith(Outer, NewSI);
953  }
954 
955  auto IsFreeOrProfitableToInvert =
956  [&](Value *V, Value *&NotV, bool &ElidesXor) {
957  if (match(V, m_Not(m_Value(NotV)))) {
958  // If V has at most 2 uses then we can get rid of the xor operation
959  // entirely.
960  ElidesXor |= !V->hasNUsesOrMore(3);
961  return true;
962  }
963 
964  if (IsFreeToInvert(V, !V->hasNUsesOrMore(3))) {
965  NotV = nullptr;
966  return true;
967  }
968 
969  return false;
970  };
971 
972  Value *NotA, *NotB, *NotC;
973  bool ElidesXor = false;
974 
975  // MIN(MIN(~A, ~B), ~C) == ~MAX(MAX(A, B), C)
976  // MIN(MAX(~A, ~B), ~C) == ~MAX(MIN(A, B), C)
977  // MAX(MIN(~A, ~B), ~C) == ~MIN(MAX(A, B), C)
978  // MAX(MAX(~A, ~B), ~C) == ~MIN(MIN(A, B), C)
979  //
980  // This transform is performance neutral if we can elide at least one xor from
981  // the set of three operands, since we'll be tacking on an xor at the very
982  // end.
985  IsFreeOrProfitableToInvert(A, NotA, ElidesXor) &&
986  IsFreeOrProfitableToInvert(B, NotB, ElidesXor) &&
987  IsFreeOrProfitableToInvert(C, NotC, ElidesXor) && ElidesXor) {
988  if (!NotA)
989  NotA = Builder.CreateNot(A);
990  if (!NotB)
991  NotB = Builder.CreateNot(B);
992  if (!NotC)
993  NotC = Builder.CreateNot(C);
994 
996  Builder, getInverseMinMaxSelectPattern(SPF1), NotA, NotB);
997  Value *NewOuter = Builder.CreateNot(generateMinMaxSelectPattern(
998  Builder, getInverseMinMaxSelectPattern(SPF2), NewInner, NotC));
999  return replaceInstUsesWith(Outer, NewOuter);
1000  }
1001 
1002  return nullptr;
1003 }
1004 
1005 /// Turn select C, (X + Y), (X - Y) --> (X + (select C, Y, (-Y))).
1006 /// This is even legal for FP.
1007 static Instruction *foldAddSubSelect(SelectInst &SI,
1008  InstCombiner::BuilderTy &Builder) {
1009  Value *CondVal = SI.getCondition();
1010  Value *TrueVal = SI.getTrueValue();
1011  Value *FalseVal = SI.getFalseValue();
1012  auto *TI = dyn_cast<Instruction>(TrueVal);
1013  auto *FI = dyn_cast<Instruction>(FalseVal);
1014  if (!TI || !FI || !TI->hasOneUse() || !FI->hasOneUse())
1015  return nullptr;
1016 
1017  Instruction *AddOp = nullptr, *SubOp = nullptr;
1018  if ((TI->getOpcode() == Instruction::Sub &&
1019  FI->getOpcode() == Instruction::Add) ||
1020  (TI->getOpcode() == Instruction::FSub &&
1021  FI->getOpcode() == Instruction::FAdd)) {
1022  AddOp = FI;
1023  SubOp = TI;
1024  } else if ((FI->getOpcode() == Instruction::Sub &&
1025  TI->getOpcode() == Instruction::Add) ||
1026  (FI->getOpcode() == Instruction::FSub &&
1027  TI->getOpcode() == Instruction::FAdd)) {
1028  AddOp = TI;
1029  SubOp = FI;
1030  }
1031 
1032  if (AddOp) {
1033  Value *OtherAddOp = nullptr;
1034  if (SubOp->getOperand(0) == AddOp->getOperand(0)) {
1035  OtherAddOp = AddOp->getOperand(1);
1036  } else if (SubOp->getOperand(0) == AddOp->getOperand(1)) {
1037  OtherAddOp = AddOp->getOperand(0);
1038  }
1039 
1040  if (OtherAddOp) {
1041  // So at this point we know we have (Y -> OtherAddOp):
1042  // select C, (add X, Y), (sub X, Z)
1043  Value *NegVal; // Compute -Z
1044  if (SI.getType()->isFPOrFPVectorTy()) {
1045  NegVal = Builder.CreateFNeg(SubOp->getOperand(1));
1046  if (Instruction *NegInst = dyn_cast<Instruction>(NegVal)) {
1047  FastMathFlags Flags = AddOp->getFastMathFlags();
1048  Flags &= SubOp->getFastMathFlags();
1049  NegInst->setFastMathFlags(Flags);
1050  }
1051  } else {
1052  NegVal = Builder.CreateNeg(SubOp->getOperand(1));
1053  }
1054 
1055  Value *NewTrueOp = OtherAddOp;
1056  Value *NewFalseOp = NegVal;
1057  if (AddOp != TI)
1058  std::swap(NewTrueOp, NewFalseOp);
1059  Value *NewSel = Builder.CreateSelect(CondVal, NewTrueOp, NewFalseOp,
1060  SI.getName() + ".p", &SI);
1061 
1062  if (SI.getType()->isFPOrFPVectorTy()) {
1063  Instruction *RI =
1064  BinaryOperator::CreateFAdd(SubOp->getOperand(0), NewSel);
1065 
1066  FastMathFlags Flags = AddOp->getFastMathFlags();
1067  Flags &= SubOp->getFastMathFlags();
1068  RI->setFastMathFlags(Flags);
1069  return RI;
1070  } else
1071  return BinaryOperator::CreateAdd(SubOp->getOperand(0), NewSel);
1072  }
1073  }
1074  return nullptr;
1075 }
1076 
1077 Instruction *InstCombiner::foldSelectExtConst(SelectInst &Sel) {
1078  Instruction *ExtInst;
1079  if (!match(Sel.getTrueValue(), m_Instruction(ExtInst)) &&
1080  !match(Sel.getFalseValue(), m_Instruction(ExtInst)))
1081  return nullptr;
1082 
1083  auto ExtOpcode = ExtInst->getOpcode();
1084  if (ExtOpcode != Instruction::ZExt && ExtOpcode != Instruction::SExt)
1085  return nullptr;
1086 
1087  // TODO: Handle larger types? That requires adjusting FoldOpIntoSelect too.
1088  Value *X = ExtInst->getOperand(0);
1089  Type *SmallType = X->getType();
1090  if (!SmallType->isIntOrIntVectorTy(1))
1091  return nullptr;
1092 
1093  Constant *C;
1094  if (!match(Sel.getTrueValue(), m_Constant(C)) &&
1095  !match(Sel.getFalseValue(), m_Constant(C)))
1096  return nullptr;
1097 
1098  // If the constant is the same after truncation to the smaller type and
1099  // extension to the original type, we can narrow the select.
1100  Value *Cond = Sel.getCondition();
1101  Type *SelType = Sel.getType();
1102  Constant *TruncC = ConstantExpr::getTrunc(C, SmallType);
1103  Constant *ExtC = ConstantExpr::getCast(ExtOpcode, TruncC, SelType);
1104  if (ExtC == C) {
1105  Value *TruncCVal = cast<Value>(TruncC);
1106  if (ExtInst == Sel.getFalseValue())
1107  std::swap(X, TruncCVal);
1108 
1109  // select Cond, (ext X), C --> ext(select Cond, X, C')
1110  // select Cond, C, (ext X) --> ext(select Cond, C', X)
1111  Value *NewSel = Builder.CreateSelect(Cond, X, TruncCVal, "narrow", &Sel);
1112  return CastInst::Create(Instruction::CastOps(ExtOpcode), NewSel, SelType);
1113  }
1114 
1115  // If one arm of the select is the extend of the condition, replace that arm
1116  // with the extension of the appropriate known bool value.
1117  if (Cond == X) {
1118  if (ExtInst == Sel.getTrueValue()) {
1119  // select X, (sext X), C --> select X, -1, C
1120  // select X, (zext X), C --> select X, 1, C
1121  Constant *One = ConstantInt::getTrue(SmallType);
1122  Constant *AllOnesOrOne = ConstantExpr::getCast(ExtOpcode, One, SelType);
1123  return SelectInst::Create(Cond, AllOnesOrOne, C, "", nullptr, &Sel);
1124  } else {
1125  // select X, C, (sext X) --> select X, C, 0
1126  // select X, C, (zext X) --> select X, C, 0
1127  Constant *Zero = ConstantInt::getNullValue(SelType);
1128  return SelectInst::Create(Cond, C, Zero, "", nullptr, &Sel);
1129  }
1130  }
1131 
1132  return nullptr;
1133 }
1134 
1135 /// Try to transform a vector select with a constant condition vector into a
1136 /// shuffle for easier combining with other shuffles and insert/extract.
1137 static Instruction *canonicalizeSelectToShuffle(SelectInst &SI) {
1138  Value *CondVal = SI.getCondition();
1139  Constant *CondC;
1140  if (!CondVal->getType()->isVectorTy() || !match(CondVal, m_Constant(CondC)))
1141  return nullptr;
1142 
1143  unsigned NumElts = CondVal->getType()->getVectorNumElements();
1145  Mask.reserve(NumElts);
1146  Type *Int32Ty = Type::getInt32Ty(CondVal->getContext());
1147  for (unsigned i = 0; i != NumElts; ++i) {
1148  Constant *Elt = CondC->getAggregateElement(i);
1149  if (!Elt)
1150  return nullptr;
1151 
1152  if (Elt->isOneValue()) {
1153  // If the select condition element is true, choose from the 1st vector.
1154  Mask.push_back(ConstantInt::get(Int32Ty, i));
1155  } else if (Elt->isNullValue()) {
1156  // If the select condition element is false, choose from the 2nd vector.
1157  Mask.push_back(ConstantInt::get(Int32Ty, i + NumElts));
1158  } else if (isa<UndefValue>(Elt)) {
1159  // Undef in a select condition (choose one of the operands) does not mean
1160  // the same thing as undef in a shuffle mask (any value is acceptable), so
1161  // give up.
1162  return nullptr;
1163  } else {
1164  // Bail out on a constant expression.
1165  return nullptr;
1166  }
1167  }
1168 
1169  return new ShuffleVectorInst(SI.getTrueValue(), SI.getFalseValue(),
1170  ConstantVector::get(Mask));
1171 }
1172 
1173 /// Reuse bitcasted operands between a compare and select:
1174 /// select (cmp (bitcast C), (bitcast D)), (bitcast' C), (bitcast' D) -->
1175 /// bitcast (select (cmp (bitcast C), (bitcast D)), (bitcast C), (bitcast D))
1176 static Instruction *foldSelectCmpBitcasts(SelectInst &Sel,
1177  InstCombiner::BuilderTy &Builder) {
1178  Value *Cond = Sel.getCondition();
1179  Value *TVal = Sel.getTrueValue();
1180  Value *FVal = Sel.getFalseValue();
1181 
1182  CmpInst::Predicate Pred;
1183  Value *A, *B;
1184  if (!match(Cond, m_Cmp(Pred, m_Value(A), m_Value(B))))
1185  return nullptr;
1186 
1187  // The select condition is a compare instruction. If the select's true/false
1188  // values are already the same as the compare operands, there's nothing to do.
1189  if (TVal == A || TVal == B || FVal == A || FVal == B)
1190  return nullptr;
1191 
1192  Value *C, *D;
1193  if (!match(A, m_BitCast(m_Value(C))) || !match(B, m_BitCast(m_Value(D))))
1194  return nullptr;
1195 
1196  // select (cmp (bitcast C), (bitcast D)), (bitcast TSrc), (bitcast FSrc)
1197  Value *TSrc, *FSrc;
1198  if (!match(TVal, m_BitCast(m_Value(TSrc))) ||
1199  !match(FVal, m_BitCast(m_Value(FSrc))))
1200  return nullptr;
1201 
1202  // If the select true/false values are *different bitcasts* of the same source
1203  // operands, make the select operands the same as the compare operands and
1204  // cast the result. This is the canonical select form for min/max.
1205  Value *NewSel;
1206  if (TSrc == C && FSrc == D) {
1207  // select (cmp (bitcast C), (bitcast D)), (bitcast' C), (bitcast' D) -->
1208  // bitcast (select (cmp A, B), A, B)
1209  NewSel = Builder.CreateSelect(Cond, A, B, "", &Sel);
1210  } else if (TSrc == D && FSrc == C) {
1211  // select (cmp (bitcast C), (bitcast D)), (bitcast' D), (bitcast' C) -->
1212  // bitcast (select (cmp A, B), B, A)
1213  NewSel = Builder.CreateSelect(Cond, B, A, "", &Sel);
1214  } else {
1215  return nullptr;
1216  }
1217  return CastInst::CreateBitOrPointerCast(NewSel, Sel.getType());
1218 }
1219 
1220 /// Try to eliminate select instructions that test the returned flag of cmpxchg
1221 /// instructions.
1222 ///
1223 /// If a select instruction tests the returned flag of a cmpxchg instruction and
1224 /// selects between the returned value of the cmpxchg instruction its compare
1225 /// operand, the result of the select will always be equal to its false value.
1226 /// For example:
1227 ///
1228 /// %0 = cmpxchg i64* %ptr, i64 %compare, i64 %new_value seq_cst seq_cst
1229 /// %1 = extractvalue { i64, i1 } %0, 1
1230 /// %2 = extractvalue { i64, i1 } %0, 0
1231 /// %3 = select i1 %1, i64 %compare, i64 %2
1232 /// ret i64 %3
1233 ///
1234 /// The returned value of the cmpxchg instruction (%2) is the original value
1235 /// located at %ptr prior to any update. If the cmpxchg operation succeeds, %2
1236 /// must have been equal to %compare. Thus, the result of the select is always
1237 /// equal to %2, and the code can be simplified to:
1238 ///
1239 /// %0 = cmpxchg i64* %ptr, i64 %compare, i64 %new_value seq_cst seq_cst
1240 /// %1 = extractvalue { i64, i1 } %0, 0
1241 /// ret i64 %1
1242 ///
1243 static Instruction *foldSelectCmpXchg(SelectInst &SI) {
1244  // A helper that determines if V is an extractvalue instruction whose
1245  // aggregate operand is a cmpxchg instruction and whose single index is equal
1246  // to I. If such conditions are true, the helper returns the cmpxchg
1247  // instruction; otherwise, a nullptr is returned.
1248  auto isExtractFromCmpXchg = [](Value *V, unsigned I) -> AtomicCmpXchgInst * {
1249  auto *Extract = dyn_cast<ExtractValueInst>(V);
1250  if (!Extract)
1251  return nullptr;
1252  if (Extract->getIndices()[0] != I)
1253  return nullptr;
1254  return dyn_cast<AtomicCmpXchgInst>(Extract->getAggregateOperand());
1255  };
1256 
1257  // If the select has a single user, and this user is a select instruction that
1258  // we can simplify, skip the cmpxchg simplification for now.
1259  if (SI.hasOneUse())
1260  if (auto *Select = dyn_cast<SelectInst>(SI.user_back()))
1261  if (Select->getCondition() == SI.getCondition())
1262  if (Select->getFalseValue() == SI.getTrueValue() ||
1263  Select->getTrueValue() == SI.getFalseValue())
1264  return nullptr;
1265 
1266  // Ensure the select condition is the returned flag of a cmpxchg instruction.
1267  auto *CmpXchg = isExtractFromCmpXchg(SI.getCondition(), 1);
1268  if (!CmpXchg)
1269  return nullptr;
1270 
1271  // Check the true value case: The true value of the select is the returned
1272  // value of the same cmpxchg used by the condition, and the false value is the
1273  // cmpxchg instruction's compare operand.
1274  if (auto *X = isExtractFromCmpXchg(SI.getTrueValue(), 0))
1275  if (X == CmpXchg && X->getCompareOperand() == SI.getFalseValue()) {
1276  SI.setTrueValue(SI.getFalseValue());
1277  return &SI;
1278  }
1279 
1280  // Check the false value case: The false value of the select is the returned
1281  // value of the same cmpxchg used by the condition, and the true value is the
1282  // cmpxchg instruction's compare operand.
1283  if (auto *X = isExtractFromCmpXchg(SI.getFalseValue(), 0))
1284  if (X == CmpXchg && X->getCompareOperand() == SI.getTrueValue()) {
1285  SI.setTrueValue(SI.getFalseValue());
1286  return &SI;
1287  }
1288 
1289  return nullptr;
1290 }
1291 
1293  Value *CondVal = SI.getCondition();
1294  Value *TrueVal = SI.getTrueValue();
1295  Value *FalseVal = SI.getFalseValue();
1296  Type *SelType = SI.getType();
1297 
1298  // FIXME: Remove this workaround when freeze related patches are done.
1299  // For select with undef operand which feeds into an equality comparison,
1300  // don't simplify it so loop unswitch can know the equality comparison
1301  // may have an undef operand. This is a workaround for PR31652 caused by
1302  // descrepancy about branch on undef between LoopUnswitch and GVN.
1303  if (isa<UndefValue>(TrueVal) || isa<UndefValue>(FalseVal)) {
1304  if (llvm::any_of(SI.users(), [&](User *U) {
1305  ICmpInst *CI = dyn_cast<ICmpInst>(U);
1306  if (CI && CI->isEquality())
1307  return true;
1308  return false;
1309  })) {
1310  return nullptr;
1311  }
1312  }
1313 
1314  if (Value *V = SimplifySelectInst(CondVal, TrueVal, FalseVal,
1315  SQ.getWithInstruction(&SI)))
1316  return replaceInstUsesWith(SI, V);
1317 
1318  if (Instruction *I = canonicalizeSelectToShuffle(SI))
1319  return I;
1320 
1321  // Canonicalize a one-use integer compare with a non-canonical predicate by
1322  // inverting the predicate and swapping the select operands. This matches a
1323  // compare canonicalization for conditional branches.
1324  // TODO: Should we do the same for FP compares?
1325  CmpInst::Predicate Pred;
1326  if (match(CondVal, m_OneUse(m_ICmp(Pred, m_Value(), m_Value()))) &&
1327  !isCanonicalPredicate(Pred)) {
1328  // Swap true/false values and condition.
1329  CmpInst *Cond = cast<CmpInst>(CondVal);
1331  SI.setOperand(1, FalseVal);
1332  SI.setOperand(2, TrueVal);
1333  SI.swapProfMetadata();
1334  Worklist.Add(Cond);
1335  return &SI;
1336  }
1337 
1338  if (SelType->isIntOrIntVectorTy(1) &&
1339  TrueVal->getType() == CondVal->getType()) {
1340  if (match(TrueVal, m_One())) {
1341  // Change: A = select B, true, C --> A = or B, C
1342  return BinaryOperator::CreateOr(CondVal, FalseVal);
1343  }
1344  if (match(TrueVal, m_Zero())) {
1345  // Change: A = select B, false, C --> A = and !B, C
1346  Value *NotCond = Builder.CreateNot(CondVal, "not." + CondVal->getName());
1347  return BinaryOperator::CreateAnd(NotCond, FalseVal);
1348  }
1349  if (match(FalseVal, m_Zero())) {
1350  // Change: A = select B, C, false --> A = and B, C
1351  return BinaryOperator::CreateAnd(CondVal, TrueVal);
1352  }
1353  if (match(FalseVal, m_One())) {
1354  // Change: A = select B, C, true --> A = or !B, C
1355  Value *NotCond = Builder.CreateNot(CondVal, "not." + CondVal->getName());
1356  return BinaryOperator::CreateOr(NotCond, TrueVal);
1357  }
1358 
1359  // select a, a, b -> a | b
1360  // select a, b, a -> a & b
1361  if (CondVal == TrueVal)
1362  return BinaryOperator::CreateOr(CondVal, FalseVal);
1363  if (CondVal == FalseVal)
1364  return BinaryOperator::CreateAnd(CondVal, TrueVal);
1365 
1366  // select a, ~a, b -> (~a) & b
1367  // select a, b, ~a -> (~a) | b
1368  if (match(TrueVal, m_Not(m_Specific(CondVal))))
1369  return BinaryOperator::CreateAnd(TrueVal, FalseVal);
1370  if (match(FalseVal, m_Not(m_Specific(CondVal))))
1371  return BinaryOperator::CreateOr(TrueVal, FalseVal);
1372  }
1373 
1374  // Selecting between two integer or vector splat integer constants?
1375  //
1376  // Note that we don't handle a scalar select of vectors:
1377  // select i1 %c, <2 x i8> <1, 1>, <2 x i8> <0, 0>
1378  // because that may need 3 instructions to splat the condition value:
1379  // extend, insertelement, shufflevector.
1380  if (SelType->isIntOrIntVectorTy() &&
1381  CondVal->getType()->isVectorTy() == SelType->isVectorTy()) {
1382  // select C, 1, 0 -> zext C to int
1383  if (match(TrueVal, m_One()) && match(FalseVal, m_Zero()))
1384  return new ZExtInst(CondVal, SelType);
1385 
1386  // select C, -1, 0 -> sext C to int
1387  if (match(TrueVal, m_AllOnes()) && match(FalseVal, m_Zero()))
1388  return new SExtInst(CondVal, SelType);
1389 
1390  // select C, 0, 1 -> zext !C to int
1391  if (match(TrueVal, m_Zero()) && match(FalseVal, m_One())) {
1392  Value *NotCond = Builder.CreateNot(CondVal, "not." + CondVal->getName());
1393  return new ZExtInst(NotCond, SelType);
1394  }
1395 
1396  // select C, 0, -1 -> sext !C to int
1397  if (match(TrueVal, m_Zero()) && match(FalseVal, m_AllOnes())) {
1398  Value *NotCond = Builder.CreateNot(CondVal, "not." + CondVal->getName());
1399  return new SExtInst(NotCond, SelType);
1400  }
1401  }
1402 
1403  // See if we are selecting two values based on a comparison of the two values.
1404  if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) {
1405  if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) {
1406  // Transform (X == Y) ? X : Y -> Y
1407  if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) {
1408  // This is not safe in general for floating point:
1409  // consider X== -0, Y== +0.
1410  // It becomes safe if either operand is a nonzero constant.
1411  ConstantFP *CFPt, *CFPf;
1412  if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
1413  !CFPt->getValueAPF().isZero()) ||
1414  ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
1415  !CFPf->getValueAPF().isZero()))
1416  return replaceInstUsesWith(SI, FalseVal);
1417  }
1418  // Transform (X une Y) ? X : Y -> X
1419  if (FCI->getPredicate() == FCmpInst::FCMP_UNE) {
1420  // This is not safe in general for floating point:
1421  // consider X== -0, Y== +0.
1422  // It becomes safe if either operand is a nonzero constant.
1423  ConstantFP *CFPt, *CFPf;
1424  if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
1425  !CFPt->getValueAPF().isZero()) ||
1426  ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
1427  !CFPf->getValueAPF().isZero()))
1428  return replaceInstUsesWith(SI, TrueVal);
1429  }
1430 
1431  // Canonicalize to use ordered comparisons by swapping the select
1432  // operands.
1433  //
1434  // e.g.
1435  // (X ugt Y) ? X : Y -> (X ole Y) ? Y : X
1436  if (FCI->hasOneUse() && FCmpInst::isUnordered(FCI->getPredicate())) {
1437  FCmpInst::Predicate InvPred = FCI->getInversePredicate();
1438  IRBuilder<>::FastMathFlagGuard FMFG(Builder);
1439  Builder.setFastMathFlags(FCI->getFastMathFlags());
1440  Value *NewCond = Builder.CreateFCmp(InvPred, TrueVal, FalseVal,
1441  FCI->getName() + ".inv");
1442 
1443  return SelectInst::Create(NewCond, FalseVal, TrueVal,
1444  SI.getName() + ".p");
1445  }
1446 
1447  // NOTE: if we wanted to, this is where to detect MIN/MAX
1448  } else if (FCI->getOperand(0) == FalseVal && FCI->getOperand(1) == TrueVal){
1449  // Transform (X == Y) ? Y : X -> X
1450  if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) {
1451  // This is not safe in general for floating point:
1452  // consider X== -0, Y== +0.
1453  // It becomes safe if either operand is a nonzero constant.
1454  ConstantFP *CFPt, *CFPf;
1455  if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
1456  !CFPt->getValueAPF().isZero()) ||
1457  ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
1458  !CFPf->getValueAPF().isZero()))
1459  return replaceInstUsesWith(SI, FalseVal);
1460  }
1461  // Transform (X une Y) ? Y : X -> Y
1462  if (FCI->getPredicate() == FCmpInst::FCMP_UNE) {
1463  // This is not safe in general for floating point:
1464  // consider X== -0, Y== +0.
1465  // It becomes safe if either operand is a nonzero constant.
1466  ConstantFP *CFPt, *CFPf;
1467  if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
1468  !CFPt->getValueAPF().isZero()) ||
1469  ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
1470  !CFPf->getValueAPF().isZero()))
1471  return replaceInstUsesWith(SI, TrueVal);
1472  }
1473 
1474  // Canonicalize to use ordered comparisons by swapping the select
1475  // operands.
1476  //
1477  // e.g.
1478  // (X ugt Y) ? X : Y -> (X ole Y) ? X : Y
1479  if (FCI->hasOneUse() && FCmpInst::isUnordered(FCI->getPredicate())) {
1480  FCmpInst::Predicate InvPred = FCI->getInversePredicate();
1481  IRBuilder<>::FastMathFlagGuard FMFG(Builder);
1482  Builder.setFastMathFlags(FCI->getFastMathFlags());
1483  Value *NewCond = Builder.CreateFCmp(InvPred, FalseVal, TrueVal,
1484  FCI->getName() + ".inv");
1485 
1486  return SelectInst::Create(NewCond, FalseVal, TrueVal,
1487  SI.getName() + ".p");
1488  }
1489 
1490  // NOTE: if we wanted to, this is where to detect MIN/MAX
1491  }
1492  // NOTE: if we wanted to, this is where to detect ABS
1493  }
1494 
1495  // See if we are selecting two values based on a comparison of the two values.
1496  if (ICmpInst *ICI = dyn_cast<ICmpInst>(CondVal))
1497  if (Instruction *Result = foldSelectInstWithICmp(SI, ICI))
1498  return Result;
1499 
1500  if (Instruction *Add = foldAddSubSelect(SI, Builder))
1501  return Add;
1502 
1503  // Turn (select C, (op X, Y), (op X, Z)) -> (op X, (select C, Y, Z))
1504  auto *TI = dyn_cast<Instruction>(TrueVal);
1505  auto *FI = dyn_cast<Instruction>(FalseVal);
1506  if (TI && FI && TI->getOpcode() == FI->getOpcode())
1507  if (Instruction *IV = foldSelectOpOp(SI, TI, FI))
1508  return IV;
1509 
1510  if (Instruction *I = foldSelectExtConst(SI))
1511  return I;
1512 
1513  // See if we can fold the select into one of our operands.
1514  if (SelType->isIntOrIntVectorTy() || SelType->isFPOrFPVectorTy()) {
1515  if (Instruction *FoldI = foldSelectIntoOp(SI, TrueVal, FalseVal))
1516  return FoldI;
1517 
1518  Value *LHS, *RHS, *LHS2, *RHS2;
1519  Instruction::CastOps CastOp;
1520  SelectPatternResult SPR = matchSelectPattern(&SI, LHS, RHS, &CastOp);
1521  auto SPF = SPR.Flavor;
1522 
1524  // Canonicalize so that
1525  // - type casts are outside select patterns.
1526  // - float clamp is transformed to min/max pattern
1527 
1528  bool IsCastNeeded = LHS->getType() != SelType;
1529  Value *CmpLHS = cast<CmpInst>(CondVal)->getOperand(0);
1530  Value *CmpRHS = cast<CmpInst>(CondVal)->getOperand(1);
1531  if (IsCastNeeded ||
1532  (LHS->getType()->isFPOrFPVectorTy() &&
1533  ((CmpLHS != LHS && CmpLHS != RHS) ||
1534  (CmpRHS != LHS && CmpRHS != RHS)))) {
1536 
1537  Value *Cmp;
1538  if (CmpInst::isIntPredicate(Pred)) {
1539  Cmp = Builder.CreateICmp(Pred, LHS, RHS);
1540  } else {
1541  IRBuilder<>::FastMathFlagGuard FMFG(Builder);
1542  auto FMF = cast<FPMathOperator>(SI.getCondition())->getFastMathFlags();
1543  Builder.setFastMathFlags(FMF);
1544  Cmp = Builder.CreateFCmp(Pred, LHS, RHS);
1545  }
1546 
1547  Value *NewSI = Builder.CreateSelect(Cmp, LHS, RHS, SI.getName(), &SI);
1548  if (!IsCastNeeded)
1549  return replaceInstUsesWith(SI, NewSI);
1550 
1551  Value *NewCast = Builder.CreateCast(CastOp, NewSI, SelType);
1552  return replaceInstUsesWith(SI, NewCast);
1553  }
1554  }
1555 
1556  if (SPF) {
1557  // MAX(MAX(a, b), a) -> MAX(a, b)
1558  // MIN(MIN(a, b), a) -> MIN(a, b)
1559  // MAX(MIN(a, b), a) -> a
1560  // MIN(MAX(a, b), a) -> a
1561  // ABS(ABS(a)) -> ABS(a)
1562  // NABS(NABS(a)) -> NABS(a)
1563  if (SelectPatternFlavor SPF2 = matchSelectPattern(LHS, LHS2, RHS2).Flavor)
1564  if (Instruction *R = foldSPFofSPF(cast<Instruction>(LHS),SPF2,LHS2,RHS2,
1565  SI, SPF, RHS))
1566  return R;
1567  if (SelectPatternFlavor SPF2 = matchSelectPattern(RHS, LHS2, RHS2).Flavor)
1568  if (Instruction *R = foldSPFofSPF(cast<Instruction>(RHS),SPF2,LHS2,RHS2,
1569  SI, SPF, LHS))
1570  return R;
1571  }
1572 
1573  // MAX(~a, ~b) -> ~MIN(a, b)
1574  if ((SPF == SPF_SMAX || SPF == SPF_UMAX) &&
1575  IsFreeToInvert(LHS, LHS->hasNUses(2)) &&
1576  IsFreeToInvert(RHS, RHS->hasNUses(2))) {
1577  // For this transform to be profitable, we need to eliminate at least two
1578  // 'not' instructions if we're going to add one 'not' instruction.
1579  int NumberOfNots =
1580  (LHS->hasNUses(2) && match(LHS, m_Not(m_Value()))) +
1581  (RHS->hasNUses(2) && match(RHS, m_Not(m_Value()))) +
1582  (SI.hasOneUse() && match(*SI.user_begin(), m_Not(m_Value())));
1583 
1584  if (NumberOfNots >= 2) {
1585  Value *NewLHS = Builder.CreateNot(LHS);
1586  Value *NewRHS = Builder.CreateNot(RHS);
1587  Value *NewCmp = SPF == SPF_SMAX ? Builder.CreateICmpSLT(NewLHS, NewRHS)
1588  : Builder.CreateICmpULT(NewLHS, NewRHS);
1589  Value *NewSI =
1590  Builder.CreateNot(Builder.CreateSelect(NewCmp, NewLHS, NewRHS));
1591  return replaceInstUsesWith(SI, NewSI);
1592  }
1593  }
1594 
1595  // TODO.
1596  // ABS(-X) -> ABS(X)
1597  }
1598 
1599  // See if we can fold the select into a phi node if the condition is a select.
1600  if (auto *PN = dyn_cast<PHINode>(SI.getCondition()))
1601  // The true/false values have to be live in the PHI predecessor's blocks.
1602  if (canSelectOperandBeMappingIntoPredBlock(TrueVal, SI) &&
1603  canSelectOperandBeMappingIntoPredBlock(FalseVal, SI))
1604  if (Instruction *NV = foldOpIntoPhi(SI, PN))
1605  return NV;
1606 
1607  if (SelectInst *TrueSI = dyn_cast<SelectInst>(TrueVal)) {
1608  if (TrueSI->getCondition()->getType() == CondVal->getType()) {
1609  // select(C, select(C, a, b), c) -> select(C, a, c)
1610  if (TrueSI->getCondition() == CondVal) {
1611  if (SI.getTrueValue() == TrueSI->getTrueValue())
1612  return nullptr;
1613  SI.setOperand(1, TrueSI->getTrueValue());
1614  return &SI;
1615  }
1616  // select(C0, select(C1, a, b), b) -> select(C0&C1, a, b)
1617  // We choose this as normal form to enable folding on the And and shortening
1618  // paths for the values (this helps GetUnderlyingObjects() for example).
1619  if (TrueSI->getFalseValue() == FalseVal && TrueSI->hasOneUse()) {
1620  Value *And = Builder.CreateAnd(CondVal, TrueSI->getCondition());
1621  SI.setOperand(0, And);
1622  SI.setOperand(1, TrueSI->getTrueValue());
1623  return &SI;
1624  }
1625  }
1626  }
1627  if (SelectInst *FalseSI = dyn_cast<SelectInst>(FalseVal)) {
1628  if (FalseSI->getCondition()->getType() == CondVal->getType()) {
1629  // select(C, a, select(C, b, c)) -> select(C, a, c)
1630  if (FalseSI->getCondition() == CondVal) {
1631  if (SI.getFalseValue() == FalseSI->getFalseValue())
1632  return nullptr;
1633  SI.setOperand(2, FalseSI->getFalseValue());
1634  return &SI;
1635  }
1636  // select(C0, a, select(C1, a, b)) -> select(C0|C1, a, b)
1637  if (FalseSI->getTrueValue() == TrueVal && FalseSI->hasOneUse()) {
1638  Value *Or = Builder.CreateOr(CondVal, FalseSI->getCondition());
1639  SI.setOperand(0, Or);
1640  SI.setOperand(2, FalseSI->getFalseValue());
1641  return &SI;
1642  }
1643  }
1644  }
1645 
1646  // Try to simplify a binop sandwiched between 2 selects with the same
1647  // condition.
1648  // select(C, binop(select(C, X, Y), W), Z) -> select(C, binop(X, W), Z)
1649  BinaryOperator *TrueBO;
1650  if (match(TrueVal, m_OneUse(m_BinOp(TrueBO)))) {
1651  if (auto *TrueBOSI = dyn_cast<SelectInst>(TrueBO->getOperand(0))) {
1652  if (TrueBOSI->getCondition() == CondVal) {
1653  TrueBO->setOperand(0, TrueBOSI->getTrueValue());
1654  Worklist.Add(TrueBO);
1655  return &SI;
1656  }
1657  }
1658  if (auto *TrueBOSI = dyn_cast<SelectInst>(TrueBO->getOperand(1))) {
1659  if (TrueBOSI->getCondition() == CondVal) {
1660  TrueBO->setOperand(1, TrueBOSI->getTrueValue());
1661  Worklist.Add(TrueBO);
1662  return &SI;
1663  }
1664  }
1665  }
1666 
1667  // select(C, Z, binop(select(C, X, Y), W)) -> select(C, Z, binop(Y, W))
1668  BinaryOperator *FalseBO;
1669  if (match(FalseVal, m_OneUse(m_BinOp(FalseBO)))) {
1670  if (auto *FalseBOSI = dyn_cast<SelectInst>(FalseBO->getOperand(0))) {
1671  if (FalseBOSI->getCondition() == CondVal) {
1672  FalseBO->setOperand(0, FalseBOSI->getFalseValue());
1673  Worklist.Add(FalseBO);
1674  return &SI;
1675  }
1676  }
1677  if (auto *FalseBOSI = dyn_cast<SelectInst>(FalseBO->getOperand(1))) {
1678  if (FalseBOSI->getCondition() == CondVal) {
1679  FalseBO->setOperand(1, FalseBOSI->getFalseValue());
1680  Worklist.Add(FalseBO);
1681  return &SI;
1682  }
1683  }
1684  }
1685 
1686  if (BinaryOperator::isNot(CondVal)) {
1688  SI.setOperand(1, FalseVal);
1689  SI.setOperand(2, TrueVal);
1690  return &SI;
1691  }
1692 
1693  if (VectorType *VecTy = dyn_cast<VectorType>(SelType)) {
1694  unsigned VWidth = VecTy->getNumElements();
1695  APInt UndefElts(VWidth, 0);
1696  APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
1697  if (Value *V = SimplifyDemandedVectorElts(&SI, AllOnesEltMask, UndefElts)) {
1698  if (V != &SI)
1699  return replaceInstUsesWith(SI, V);
1700  return &SI;
1701  }
1702  }
1703 
1704  // See if we can determine the result of this select based on a dominating
1705  // condition.
1706  BasicBlock *Parent = SI.getParent();
1707  if (BasicBlock *Dom = Parent->getSinglePredecessor()) {
1708  auto *PBI = dyn_cast_or_null<BranchInst>(Dom->getTerminator());
1709  if (PBI && PBI->isConditional() &&
1710  PBI->getSuccessor(0) != PBI->getSuccessor(1) &&
1711  (PBI->getSuccessor(0) == Parent || PBI->getSuccessor(1) == Parent)) {
1712  bool CondIsTrue = PBI->getSuccessor(0) == Parent;
1713  Optional<bool> Implication = isImpliedCondition(
1714  PBI->getCondition(), SI.getCondition(), DL, CondIsTrue);
1715  if (Implication) {
1716  Value *V = *Implication ? TrueVal : FalseVal;
1717  return replaceInstUsesWith(SI, V);
1718  }
1719  }
1720  }
1721 
1722  // If we can compute the condition, there's no need for a select.
1723  // Like the above fold, we are attempting to reduce compile-time cost by
1724  // putting this fold here with limitations rather than in InstSimplify.
1725  // The motivation for this call into value tracking is to take advantage of
1726  // the assumption cache, so make sure that is populated.
1727  if (!CondVal->getType()->isVectorTy() && !AC.assumptions().empty()) {
1728  KnownBits Known(1);
1729  computeKnownBits(CondVal, Known, 0, &SI);
1730  if (Known.One.isOneValue())
1731  return replaceInstUsesWith(SI, TrueVal);
1732  if (Known.Zero.isOneValue())
1733  return replaceInstUsesWith(SI, FalseVal);
1734  }
1735 
1736  if (Instruction *BitCastSel = foldSelectCmpBitcasts(SI, Builder))
1737  return BitCastSel;
1738 
1739  // Simplify selects that test the returned flag of cmpxchg instructions.
1740  if (Instruction *Select = foldSelectCmpXchg(SI))
1741  return Select;
1742 
1743  return nullptr;
1744 }
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:574
uint64_t CallInst * C
static bool isSelect01(const APInt &C1I, const APInt &C2I)
static ConstantInt * getFalse(LLVMContext &Context)
Definition: Constants.cpp:523
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:1638
This class is the base class for the comparison instructions.
Definition: InstrTypes.h:843
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 isSignMask() const
Check if the APInt&#39;s value is returned by getSignMask.
Definition: APInt.h:466
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).
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:555
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:1395
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
BinaryOps getOpcode() const
Definition: InstrTypes.h:523
Value * CreateICmpULT(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1562
Value * CreateXor(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1099
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:514
match_zero m_Zero()
Match an arbitrary zero/null constant.
Definition: PatternMatch.h:145
This class represents zero extension of integer types.
Value * CreateICmpSLT(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1574
bool slt(const APInt &RHS) const
Signed less than comparison.
Definition: APInt.h:1183
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 than
Definition: InstrTypes.h:878
0 1 0 0 True if ordered and less than
Definition: InstrTypes.h:859
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:728
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:869
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:1253
static bool isEquality(Predicate P)
Return true if this predicate is either EQ or NE.
This class represents a sign extension of integer types.
bool isVectorTy() const
True if this is an instance of VectorType.
Definition: Type.h:227
void reserve(size_type N)
Definition: SmallVector.h:380
bool sle(const APInt &RHS) const
Signed less or equal comparison.
Definition: APInt.h:1218
void copyIRFlags(const Value *V, bool IncludeWrapFlags=true)
Convenience method to copy supported exact, fast-math, and (optionally) wrapping flags from V to this...
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:1488
Signed maximum.
static Constant * getNullValue(Type *Ty)
Constructor to create a &#39;0&#39; constant of arbitrary type.
Definition: Constants.cpp:207
Value * CreateNot(Value *V, const Twine &Name="")
Definition: IRBuilder.h:1146
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(Type *SelType, const ICmpInst *IC, APInt TrueVal, APInt FalseVal, InstCombiner::BuilderTy &Builder)
If one of the constants is zero (we know they can&#39;t both be) and we have an icmp instruction with zer...
BinaryOp_match< LHS, RHS, Instruction::Xor > m_Xor(const LHS &L, const RHS &R)
Definition: PatternMatch.h:586
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:951
Absolute value.
bool isUnsigned() const
Determine if this instruction is using an unsigned comparison.
Definition: InstrTypes.h:1000
CastClass_match< OpTy, Instruction::Trunc > m_Trunc(const OpTy &Op)
Matches Trunc.
Definition: PatternMatch.h:912
This provides a uniform API for creating instructions and inserting them into a basic block: either a...
Definition: IRBuilder.h:668
static Constant * getSExt(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1556
Value * CreateAdd(Value *LHS, Value *RHS, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:893
static SelectPatternFlavor getInverseMinMaxSelectPattern(SelectPatternFlavor SPF)
This file implements a class to represent arbitrary precision integral constant values and operations...
not_match< LHS > m_Not(const LHS &L)
Definition: PatternMatch.h:985
static Constant * getZExt(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1570
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:86
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.
Definition: PatternMatch.h:924
This instruction compares its operands according to the predicate given to the constructor.
MaxMin_match< ICmpInst, LHS, RHS, smin_pred_ty > m_SMin(const LHS &L, const RHS &R)
unsigned getOpcode() const
Returns a member of one of the enums like Instruction::Add.
Definition: Instruction.h:125
bool isIntOrIntVectorTy() const
Return true if this is an integer type or a vector of integer types.
Definition: Type.h:203
cst_pred_ty< is_power2 > m_Power2()
Match an integer or vector power of 2.
Definition: PatternMatch.h:330
void takeName(Value *V)
Transfer the name from V to this value.
Definition: Value.cpp:292
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:154
void replaceUsesOfWith(Value *From, Value *To)
Replace uses of one Value with another.
Definition: User.cpp:22
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:1083
Constant * getAggregateElement(unsigned Elt) const
For aggregates (struct/array/vector) return the constant that corresponds to the specified element if...
Definition: Constants.cpp:277
Type * getScalarType() const
If this is a vector type, return the element type, otherwise return &#39;this&#39;.
Definition: Type.h:301
Value * CreateFCmp(CmpInst::Predicate P, Value *LHS, Value *RHS, const Twine &Name="", MDNode *FPMathTag=nullptr)
Definition: IRBuilder.h:1645
OneUse_match< T > m_OneUse(const T &SubPattern)
Definition: PatternMatch.h:63
bool hasNUsesOrMore(unsigned N) const
Return true if this value has N users or more.
Definition: Value.cpp:136
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:389
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:128
apint_match m_APInt(const APInt *&Res)
Match a ConstantInt or splatted ConstantVector, binding the specified pointer to the contained APInt...
Definition: PatternMatch.h:260
const BasicBlock * getSinglePredecessor() const
Return the predecessor of this block if it has a single predecessor block.
Definition: BasicBlock.cpp:217
Value * CreateAShr(Value *LHS, Value *RHS, const Twine &Name="", bool isExact=false)
Definition: IRBuilder.h:1049
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:580
bool ult(const APInt &RHS) const
Unsigned less than comparison.
Definition: APInt.h:1164
CastClass_match< OpTy, Instruction::BitCast > m_BitCast(const OpTy &Op)
Matches BitCast.
Definition: PatternMatch.h:900
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:1693
ConstantFP - Floating Point Values [float, double].
Definition: Constants.h:264
bool isOneValue() const
Determine if this is a value of 1.
Definition: APInt.h:404
static APInt getOneBitSet(unsigned numBits, unsigned BitNo)
Return an APInt with exactly one bit set in the result.
Definition: APInt.h:581
specificval_ty m_Specific(const Value *V)
Match if we have a specific specified value.
Definition: PatternMatch.h:382
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:820
Value * CreateNeg(Value *V, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:1124
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:853
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:131
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:880
const APFloat & getValueAPF() const
Definition: Constants.h:294
CastClass_match< OpTy, Instruction::SExt > m_SExt(const OpTy &Op)
Matches SExt.
Definition: PatternMatch.h:918
Floating point maxnum.
0 0 1 0 True if ordered and greater than
Definition: InstrTypes.h:857
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:176
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
Unsigned maximum.
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:864
1 1 0 0 True if unordered or less than
Definition: InstrTypes.h:867
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:63
Floating point minnum.
signed less than
Definition: InstrTypes.h:882
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:1542
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:560
bool uge(const APInt &RHS) const
Unsigned greater or equal comparison.
Definition: APInt.h:1272
static ConstantInt * getTrue(LLVMContext &Context)
Definition: Constants.cpp:516
bool isCommutative() const
Return true if the instruction is commutative:
Definition: Instruction.h:451
Instruction * visitSelectInst(SelectInst &SI)
void setPredicate(Predicate P)
Set the predicate for this instruction to the specified value.
Definition: InstrTypes.h:932
void setOperand(unsigned i, Value *Val)
Definition: User.h:159
unsigned logBase2() const
Definition: APInt.h:1727
void swap(llvm::BitVector &LHS, llvm::BitVector &RHS)
Implement std::swap in terms of BitVector swap.
Definition: BitVector.h:923
unsigned getVectorNumElements() const
Definition: DerivedTypes.h:462
bool isIntPredicate() const
Definition: InstrTypes.h:945
Class to represent vector types.
Definition: DerivedTypes.h:393
Class for arbitrary precision integers.
Definition: APInt.h:69
bool ule(const APInt &RHS) const
Unsigned less or equal comparison.
Definition: APInt.h:1202
bool isPowerOf2() const
Check if this APInt&#39;s value is a power of two greater than zero.
Definition: APInt.h:457
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 greather or equal comparison.
Definition: APInt.h:1288
iterator_range< user_iterator > users()
Definition: Value.h:401
static Constant * getCast(unsigned ops, Constant *C, Type *Ty, bool OnlyIfReduced=false)
Convenience function for getting a Cast operation.
Definition: Constants.cpp:1435
Value * CreateShl(Value *LHS, Value *RHS, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:1012
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:1234
Predicate getPredicate() const
Return the predicate for this instruction.
Definition: InstrTypes.h:927
static cl::opt< bool > NeedAnd("extract-needand", cl::init(true), cl::Hidden, cl::desc("Require & in extract patterns"))
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?
static bool isUnordered(Predicate predicate)
Determine if the predicate is an unordered operation.
match_one m_One()
Match an integer 1 or a vector with all elements equal to 1.
Definition: PatternMatch.h:194
StringRef getName() const
Return a constant reference to the value&#39;s name.
Definition: Value.cpp:220
bool isEquality() const
Return true if this predicate is either EQ or NE.
#define I(x, y, z)
Definition: MD5.cpp:58
void setArgOperand(unsigned i, Value *v)
MaxMin_match< ICmpInst, LHS, RHS, smax_pred_ty > m_SMax(const LHS &L, const RHS &R)
static Value * generateMinMaxSelectPattern(InstCombiner::BuilderTy &Builder, SelectPatternFlavor SPF, Value *A, Value *B)
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)
1 0 1 0 True if unordered or greater than
Definition: InstrTypes.h:865
Signed minimum.
Value * CreateAnd(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1067
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:719
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:127
Value * CreateCast(Instruction::CastOps Op, Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1480
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
user_iterator user_begin()
Definition: Value.h:377
static APInt getSignedMinValue(unsigned numBits)
Gets minimum signed value of APInt for a specific bit width.
Definition: APInt.h:538
match_all_ones m_AllOnes()
Match an integer or vector with all bits set to true.
Definition: PatternMatch.h:205
0 0 0 1 True if ordered and equal
Definition: InstrTypes.h:856
LLVM Value Representation.
Definition: Value.h:73
static CmpInst::Predicate getCmpPredicateForMinMax(SelectPatternFlavor SPF, bool Ordered=false)
This file provides internal interfaces used to implement the InstCombine.
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:221
void moveBefore(Instruction *MovePos)
Unlink this instruction from its current basic block and insert it into the basic block that MovePos ...
Definition: Instruction.cpp:88
Value * CreateLShr(Value *LHS, Value *RHS, const Twine &Name="", bool isExact=false)
Definition: IRBuilder.h:1031
bool hasOneUse() const
Return true if there is exactly one user of this value.
Definition: Value.h:414
Convenience struct for specifying and reasoning about fast-math flags.
Definition: Operator.h:160
unsigned greater than
Definition: InstrTypes.h:876
Predicate getSwappedPredicate() const
For example, EQ->EQ, SLE->SGE, ULT->UGT, OEQ->OEQ, ULE->UGE, OLT->OGT, etc.
Definition: InstrTypes.h:967
static APInt getNullValue(unsigned numBits)
Get the &#39;0&#39; value.
Definition: APInt.h:562
specific_intval m_SpecificInt(uint64_t V)
Match a specific integer value or vector with all elements equal to the value.
Definition: PatternMatch.h:443
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)
Determine which bits of V are known to be either zero or one and return them in the KnownZero/KnownOn...
static Constant * get(ArrayRef< Constant *> V)
Definition: Constants.cpp:984
Value * CreateFNeg(Value *V, const Twine &Name="", MDNode *FPMathTag=nullptr)
Definition: IRBuilder.h:1139
bind_ty< Instruction > m_Instruction(Instruction *&I)
Match an instruction, capturing it if we match.
Definition: PatternMatch.h:359
bool isNullValue() const
Determine if all bits are clear.
Definition: APInt.h:399
IntegerType * Int32Ty
A wrapper class for inspecting calls to intrinsic functions.
Definition: IntrinsicInst.h:44
const BasicBlock * getParent() const
Definition: Instruction.h:66
CmpClass_match< LHS, RHS, ICmpInst, ICmpInst::Predicate > m_ICmp(ICmpInst::Predicate &Pred, const LHS &L, const RHS &R)
Definition: PatternMatch.h:837