LLVM  7.0.0svn
InstCombineCasts.cpp
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1 //===- InstCombineCasts.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 visit functions for cast operations.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "InstCombineInternal.h"
15 #include "llvm/ADT/SetVector.h"
18 #include "llvm/IR/DataLayout.h"
19 #include "llvm/IR/DIBuilder.h"
20 #include "llvm/IR/PatternMatch.h"
21 #include "llvm/Support/KnownBits.h"
22 using namespace llvm;
23 using namespace PatternMatch;
24 
25 #define DEBUG_TYPE "instcombine"
26 
27 /// Analyze 'Val', seeing if it is a simple linear expression.
28 /// If so, decompose it, returning some value X, such that Val is
29 /// X*Scale+Offset.
30 ///
31 static Value *decomposeSimpleLinearExpr(Value *Val, unsigned &Scale,
32  uint64_t &Offset) {
33  if (ConstantInt *CI = dyn_cast<ConstantInt>(Val)) {
34  Offset = CI->getZExtValue();
35  Scale = 0;
36  return ConstantInt::get(Val->getType(), 0);
37  }
38 
39  if (BinaryOperator *I = dyn_cast<BinaryOperator>(Val)) {
40  // Cannot look past anything that might overflow.
42  if (OBI && !OBI->hasNoUnsignedWrap() && !OBI->hasNoSignedWrap()) {
43  Scale = 1;
44  Offset = 0;
45  return Val;
46  }
47 
48  if (ConstantInt *RHS = dyn_cast<ConstantInt>(I->getOperand(1))) {
49  if (I->getOpcode() == Instruction::Shl) {
50  // This is a value scaled by '1 << the shift amt'.
51  Scale = UINT64_C(1) << RHS->getZExtValue();
52  Offset = 0;
53  return I->getOperand(0);
54  }
55 
56  if (I->getOpcode() == Instruction::Mul) {
57  // This value is scaled by 'RHS'.
58  Scale = RHS->getZExtValue();
59  Offset = 0;
60  return I->getOperand(0);
61  }
62 
63  if (I->getOpcode() == Instruction::Add) {
64  // We have X+C. Check to see if we really have (X*C2)+C1,
65  // where C1 is divisible by C2.
66  unsigned SubScale;
67  Value *SubVal =
68  decomposeSimpleLinearExpr(I->getOperand(0), SubScale, Offset);
69  Offset += RHS->getZExtValue();
70  Scale = SubScale;
71  return SubVal;
72  }
73  }
74  }
75 
76  // Otherwise, we can't look past this.
77  Scale = 1;
78  Offset = 0;
79  return Val;
80 }
81 
82 /// If we find a cast of an allocation instruction, try to eliminate the cast by
83 /// moving the type information into the alloc.
84 Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI,
85  AllocaInst &AI) {
86  PointerType *PTy = cast<PointerType>(CI.getType());
87 
88  BuilderTy AllocaBuilder(Builder);
89  AllocaBuilder.SetInsertPoint(&AI);
90 
91  // Get the type really allocated and the type casted to.
92  Type *AllocElTy = AI.getAllocatedType();
93  Type *CastElTy = PTy->getElementType();
94  if (!AllocElTy->isSized() || !CastElTy->isSized()) return nullptr;
95 
96  unsigned AllocElTyAlign = DL.getABITypeAlignment(AllocElTy);
97  unsigned CastElTyAlign = DL.getABITypeAlignment(CastElTy);
98  if (CastElTyAlign < AllocElTyAlign) return nullptr;
99 
100  // If the allocation has multiple uses, only promote it if we are strictly
101  // increasing the alignment of the resultant allocation. If we keep it the
102  // same, we open the door to infinite loops of various kinds.
103  if (!AI.hasOneUse() && CastElTyAlign == AllocElTyAlign) return nullptr;
104 
105  uint64_t AllocElTySize = DL.getTypeAllocSize(AllocElTy);
106  uint64_t CastElTySize = DL.getTypeAllocSize(CastElTy);
107  if (CastElTySize == 0 || AllocElTySize == 0) return nullptr;
108 
109  // If the allocation has multiple uses, only promote it if we're not
110  // shrinking the amount of memory being allocated.
111  uint64_t AllocElTyStoreSize = DL.getTypeStoreSize(AllocElTy);
112  uint64_t CastElTyStoreSize = DL.getTypeStoreSize(CastElTy);
113  if (!AI.hasOneUse() && CastElTyStoreSize < AllocElTyStoreSize) return nullptr;
114 
115  // See if we can satisfy the modulus by pulling a scale out of the array
116  // size argument.
117  unsigned ArraySizeScale;
118  uint64_t ArrayOffset;
119  Value *NumElements = // See if the array size is a decomposable linear expr.
120  decomposeSimpleLinearExpr(AI.getOperand(0), ArraySizeScale, ArrayOffset);
121 
122  // If we can now satisfy the modulus, by using a non-1 scale, we really can
123  // do the xform.
124  if ((AllocElTySize*ArraySizeScale) % CastElTySize != 0 ||
125  (AllocElTySize*ArrayOffset ) % CastElTySize != 0) return nullptr;
126 
127  unsigned Scale = (AllocElTySize*ArraySizeScale)/CastElTySize;
128  Value *Amt = nullptr;
129  if (Scale == 1) {
130  Amt = NumElements;
131  } else {
132  Amt = ConstantInt::get(AI.getArraySize()->getType(), Scale);
133  // Insert before the alloca, not before the cast.
134  Amt = AllocaBuilder.CreateMul(Amt, NumElements);
135  }
136 
137  if (uint64_t Offset = (AllocElTySize*ArrayOffset)/CastElTySize) {
139  Offset, true);
140  Amt = AllocaBuilder.CreateAdd(Amt, Off);
141  }
142 
143  AllocaInst *New = AllocaBuilder.CreateAlloca(CastElTy, Amt);
144  New->setAlignment(AI.getAlignment());
145  New->takeName(&AI);
147 
148  // If the allocation has multiple real uses, insert a cast and change all
149  // things that used it to use the new cast. This will also hack on CI, but it
150  // will die soon.
151  if (!AI.hasOneUse()) {
152  // New is the allocation instruction, pointer typed. AI is the original
153  // allocation instruction, also pointer typed. Thus, cast to use is BitCast.
154  Value *NewCast = AllocaBuilder.CreateBitCast(New, AI.getType(), "tmpcast");
155  replaceInstUsesWith(AI, NewCast);
156  }
157  return replaceInstUsesWith(CI, New);
158 }
159 
160 /// Given an expression that CanEvaluateTruncated or CanEvaluateSExtd returns
161 /// true for, actually insert the code to evaluate the expression.
162 Value *InstCombiner::EvaluateInDifferentType(Value *V, Type *Ty,
163  bool isSigned) {
164  if (Constant *C = dyn_cast<Constant>(V)) {
165  C = ConstantExpr::getIntegerCast(C, Ty, isSigned /*Sext or ZExt*/);
166  // If we got a constantexpr back, try to simplify it with DL info.
167  if (Constant *FoldedC = ConstantFoldConstant(C, DL, &TLI))
168  C = FoldedC;
169  return C;
170  }
171 
172  // Otherwise, it must be an instruction.
173  Instruction *I = cast<Instruction>(V);
174  Instruction *Res = nullptr;
175  unsigned Opc = I->getOpcode();
176  switch (Opc) {
177  case Instruction::Add:
178  case Instruction::Sub:
179  case Instruction::Mul:
180  case Instruction::And:
181  case Instruction::Or:
182  case Instruction::Xor:
183  case Instruction::AShr:
184  case Instruction::LShr:
185  case Instruction::Shl:
186  case Instruction::UDiv:
187  case Instruction::URem: {
188  Value *LHS = EvaluateInDifferentType(I->getOperand(0), Ty, isSigned);
189  Value *RHS = EvaluateInDifferentType(I->getOperand(1), Ty, isSigned);
190  Res = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
191  break;
192  }
193  case Instruction::Trunc:
194  case Instruction::ZExt:
195  case Instruction::SExt:
196  // If the source type of the cast is the type we're trying for then we can
197  // just return the source. There's no need to insert it because it is not
198  // new.
199  if (I->getOperand(0)->getType() == Ty)
200  return I->getOperand(0);
201 
202  // Otherwise, must be the same type of cast, so just reinsert a new one.
203  // This also handles the case of zext(trunc(x)) -> zext(x).
204  Res = CastInst::CreateIntegerCast(I->getOperand(0), Ty,
205  Opc == Instruction::SExt);
206  break;
207  case Instruction::Select: {
208  Value *True = EvaluateInDifferentType(I->getOperand(1), Ty, isSigned);
209  Value *False = EvaluateInDifferentType(I->getOperand(2), Ty, isSigned);
210  Res = SelectInst::Create(I->getOperand(0), True, False);
211  break;
212  }
213  case Instruction::PHI: {
214  PHINode *OPN = cast<PHINode>(I);
215  PHINode *NPN = PHINode::Create(Ty, OPN->getNumIncomingValues());
216  for (unsigned i = 0, e = OPN->getNumIncomingValues(); i != e; ++i) {
217  Value *V =
218  EvaluateInDifferentType(OPN->getIncomingValue(i), Ty, isSigned);
219  NPN->addIncoming(V, OPN->getIncomingBlock(i));
220  }
221  Res = NPN;
222  break;
223  }
224  default:
225  // TODO: Can handle more cases here.
226  llvm_unreachable("Unreachable!");
227  }
228 
229  Res->takeName(I);
230  return InsertNewInstWith(Res, *I);
231 }
232 
233 Instruction::CastOps InstCombiner::isEliminableCastPair(const CastInst *CI1,
234  const CastInst *CI2) {
235  Type *SrcTy = CI1->getSrcTy();
236  Type *MidTy = CI1->getDestTy();
237  Type *DstTy = CI2->getDestTy();
238 
239  Instruction::CastOps firstOp = CI1->getOpcode();
240  Instruction::CastOps secondOp = CI2->getOpcode();
241  Type *SrcIntPtrTy =
242  SrcTy->isPtrOrPtrVectorTy() ? DL.getIntPtrType(SrcTy) : nullptr;
243  Type *MidIntPtrTy =
244  MidTy->isPtrOrPtrVectorTy() ? DL.getIntPtrType(MidTy) : nullptr;
245  Type *DstIntPtrTy =
246  DstTy->isPtrOrPtrVectorTy() ? DL.getIntPtrType(DstTy) : nullptr;
247  unsigned Res = CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy,
248  DstTy, SrcIntPtrTy, MidIntPtrTy,
249  DstIntPtrTy);
250 
251  // We don't want to form an inttoptr or ptrtoint that converts to an integer
252  // type that differs from the pointer size.
253  if ((Res == Instruction::IntToPtr && SrcTy != DstIntPtrTy) ||
254  (Res == Instruction::PtrToInt && DstTy != SrcIntPtrTy))
255  Res = 0;
256 
257  return Instruction::CastOps(Res);
258 }
259 
260 /// Implement the transforms common to all CastInst visitors.
262  Value *Src = CI.getOperand(0);
263 
264  // Try to eliminate a cast of a cast.
265  if (auto *CSrc = dyn_cast<CastInst>(Src)) { // A->B->C cast
266  if (Instruction::CastOps NewOpc = isEliminableCastPair(CSrc, &CI)) {
267  // The first cast (CSrc) is eliminable so we need to fix up or replace
268  // the second cast (CI). CSrc will then have a good chance of being dead.
269  auto *Res = CastInst::Create(NewOpc, CSrc->getOperand(0), CI.getType());
270 
271  // If the eliminable cast has debug users, insert a debug value after the
272  // cast pointing to the new Value.
274  findDbgUsers(CSrcDbgInsts, CSrc);
275  if (CSrcDbgInsts.size()) {
276  DIBuilder DIB(*CI.getModule());
277  for (auto *DII : CSrcDbgInsts)
278  DIB.insertDbgValueIntrinsic(
279  Res, DII->getVariable(), DII->getExpression(),
280  DII->getDebugLoc().get(), &*std::next(CI.getIterator()));
281  }
282  return Res;
283  }
284  }
285 
286  if (auto *Sel = dyn_cast<SelectInst>(Src)) {
287  // We are casting a select. Try to fold the cast into the select, but only
288  // if the select does not have a compare instruction with matching operand
289  // types. Creating a select with operands that are different sizes than its
290  // condition may inhibit other folds and lead to worse codegen.
291  auto *Cmp = dyn_cast<CmpInst>(Sel->getCondition());
292  if (!Cmp || Cmp->getOperand(0)->getType() != Sel->getType())
293  if (Instruction *NV = FoldOpIntoSelect(CI, Sel))
294  return NV;
295  }
296 
297  // If we are casting a PHI, then fold the cast into the PHI.
298  if (auto *PN = dyn_cast<PHINode>(Src)) {
299  // Don't do this if it would create a PHI node with an illegal type from a
300  // legal type.
301  if (!Src->getType()->isIntegerTy() || !CI.getType()->isIntegerTy() ||
302  shouldChangeType(CI.getType(), Src->getType()))
303  if (Instruction *NV = foldOpIntoPhi(CI, PN))
304  return NV;
305  }
306 
307  return nullptr;
308 }
309 
310 /// Constants and extensions/truncates from the destination type are always
311 /// free to be evaluated in that type. This is a helper for canEvaluate*.
312 static bool canAlwaysEvaluateInType(Value *V, Type *Ty) {
313  if (isa<Constant>(V))
314  return true;
315  Value *X;
316  if ((match(V, m_ZExtOrSExt(m_Value(X))) || match(V, m_Trunc(m_Value(X)))) &&
317  X->getType() == Ty)
318  return true;
319 
320  return false;
321 }
322 
323 /// Filter out values that we can not evaluate in the destination type for free.
324 /// This is a helper for canEvaluate*.
325 static bool canNotEvaluateInType(Value *V, Type *Ty) {
326  assert(!isa<Constant>(V) && "Constant should already be handled.");
327  if (!isa<Instruction>(V))
328  return true;
329  // We don't extend or shrink something that has multiple uses -- doing so
330  // would require duplicating the instruction which isn't profitable.
331  if (!V->hasOneUse())
332  return true;
333 
334  return false;
335 }
336 
337 /// Return true if we can evaluate the specified expression tree as type Ty
338 /// instead of its larger type, and arrive with the same value.
339 /// This is used by code that tries to eliminate truncates.
340 ///
341 /// Ty will always be a type smaller than V. We should return true if trunc(V)
342 /// can be computed by computing V in the smaller type. If V is an instruction,
343 /// then trunc(inst(x,y)) can be computed as inst(trunc(x),trunc(y)), which only
344 /// makes sense if x and y can be efficiently truncated.
345 ///
346 /// This function works on both vectors and scalars.
347 ///
348 static bool canEvaluateTruncated(Value *V, Type *Ty, InstCombiner &IC,
349  Instruction *CxtI) {
350  if (canAlwaysEvaluateInType(V, Ty))
351  return true;
352  if (canNotEvaluateInType(V, Ty))
353  return false;
354 
355  auto *I = cast<Instruction>(V);
356  Type *OrigTy = V->getType();
357  switch (I->getOpcode()) {
358  case Instruction::Add:
359  case Instruction::Sub:
360  case Instruction::Mul:
361  case Instruction::And:
362  case Instruction::Or:
363  case Instruction::Xor:
364  // These operators can all arbitrarily be extended or truncated.
365  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI) &&
366  canEvaluateTruncated(I->getOperand(1), Ty, IC, CxtI);
367 
368  case Instruction::UDiv:
369  case Instruction::URem: {
370  // UDiv and URem can be truncated if all the truncated bits are zero.
371  uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
372  uint32_t BitWidth = Ty->getScalarSizeInBits();
373  assert(BitWidth < OrigBitWidth && "Unexpected bitwidths!");
374  APInt Mask = APInt::getBitsSetFrom(OrigBitWidth, BitWidth);
375  if (IC.MaskedValueIsZero(I->getOperand(0), Mask, 0, CxtI) &&
376  IC.MaskedValueIsZero(I->getOperand(1), Mask, 0, CxtI)) {
377  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI) &&
378  canEvaluateTruncated(I->getOperand(1), Ty, IC, CxtI);
379  }
380  break;
381  }
382  case Instruction::Shl: {
383  // If we are truncating the result of this SHL, and if it's a shift of a
384  // constant amount, we can always perform a SHL in a smaller type.
385  const APInt *Amt;
386  if (match(I->getOperand(1), m_APInt(Amt))) {
387  uint32_t BitWidth = Ty->getScalarSizeInBits();
388  if (Amt->getLimitedValue(BitWidth) < BitWidth)
389  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
390  }
391  break;
392  }
393  case Instruction::LShr: {
394  // If this is a truncate of a logical shr, we can truncate it to a smaller
395  // lshr iff we know that the bits we would otherwise be shifting in are
396  // already zeros.
397  const APInt *Amt;
398  if (match(I->getOperand(1), m_APInt(Amt))) {
399  uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
400  uint32_t BitWidth = Ty->getScalarSizeInBits();
401  if (Amt->getLimitedValue(BitWidth) < BitWidth &&
402  IC.MaskedValueIsZero(I->getOperand(0),
403  APInt::getBitsSetFrom(OrigBitWidth, BitWidth), 0, CxtI)) {
404  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
405  }
406  }
407  break;
408  }
409  case Instruction::AShr: {
410  // If this is a truncate of an arithmetic shr, we can truncate it to a
411  // smaller ashr iff we know that all the bits from the sign bit of the
412  // original type and the sign bit of the truncate type are similar.
413  // TODO: It is enough to check that the bits we would be shifting in are
414  // similar to sign bit of the truncate type.
415  const APInt *Amt;
416  if (match(I->getOperand(1), m_APInt(Amt))) {
417  uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
418  uint32_t BitWidth = Ty->getScalarSizeInBits();
419  if (Amt->getLimitedValue(BitWidth) < BitWidth &&
420  OrigBitWidth - BitWidth <
421  IC.ComputeNumSignBits(I->getOperand(0), 0, CxtI))
422  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
423  }
424  break;
425  }
426  case Instruction::Trunc:
427  // trunc(trunc(x)) -> trunc(x)
428  return true;
429  case Instruction::ZExt:
430  case Instruction::SExt:
431  // trunc(ext(x)) -> ext(x) if the source type is smaller than the new dest
432  // trunc(ext(x)) -> trunc(x) if the source type is larger than the new dest
433  return true;
434  case Instruction::Select: {
435  SelectInst *SI = cast<SelectInst>(I);
436  return canEvaluateTruncated(SI->getTrueValue(), Ty, IC, CxtI) &&
437  canEvaluateTruncated(SI->getFalseValue(), Ty, IC, CxtI);
438  }
439  case Instruction::PHI: {
440  // We can change a phi if we can change all operands. Note that we never
441  // get into trouble with cyclic PHIs here because we only consider
442  // instructions with a single use.
443  PHINode *PN = cast<PHINode>(I);
444  for (Value *IncValue : PN->incoming_values())
445  if (!canEvaluateTruncated(IncValue, Ty, IC, CxtI))
446  return false;
447  return true;
448  }
449  default:
450  // TODO: Can handle more cases here.
451  break;
452  }
453 
454  return false;
455 }
456 
457 /// Given a vector that is bitcast to an integer, optionally logically
458 /// right-shifted, and truncated, convert it to an extractelement.
459 /// Example (big endian):
460 /// trunc (lshr (bitcast <4 x i32> %X to i128), 32) to i32
461 /// --->
462 /// extractelement <4 x i32> %X, 1
464  Value *TruncOp = Trunc.getOperand(0);
465  Type *DestType = Trunc.getType();
466  if (!TruncOp->hasOneUse() || !isa<IntegerType>(DestType))
467  return nullptr;
468 
469  Value *VecInput = nullptr;
470  ConstantInt *ShiftVal = nullptr;
471  if (!match(TruncOp, m_CombineOr(m_BitCast(m_Value(VecInput)),
472  m_LShr(m_BitCast(m_Value(VecInput)),
473  m_ConstantInt(ShiftVal)))) ||
474  !isa<VectorType>(VecInput->getType()))
475  return nullptr;
476 
477  VectorType *VecType = cast<VectorType>(VecInput->getType());
478  unsigned VecWidth = VecType->getPrimitiveSizeInBits();
479  unsigned DestWidth = DestType->getPrimitiveSizeInBits();
480  unsigned ShiftAmount = ShiftVal ? ShiftVal->getZExtValue() : 0;
481 
482  if ((VecWidth % DestWidth != 0) || (ShiftAmount % DestWidth != 0))
483  return nullptr;
484 
485  // If the element type of the vector doesn't match the result type,
486  // bitcast it to a vector type that we can extract from.
487  unsigned NumVecElts = VecWidth / DestWidth;
488  if (VecType->getElementType() != DestType) {
489  VecType = VectorType::get(DestType, NumVecElts);
490  VecInput = IC.Builder.CreateBitCast(VecInput, VecType, "bc");
491  }
492 
493  unsigned Elt = ShiftAmount / DestWidth;
494  if (IC.getDataLayout().isBigEndian())
495  Elt = NumVecElts - 1 - Elt;
496 
497  return ExtractElementInst::Create(VecInput, IC.Builder.getInt32(Elt));
498 }
499 
500 /// Rotate left/right may occur in a wider type than necessary because of type
501 /// promotion rules. Try to narrow all of the component instructions.
502 Instruction *InstCombiner::narrowRotate(TruncInst &Trunc) {
503  assert((isa<VectorType>(Trunc.getSrcTy()) ||
504  shouldChangeType(Trunc.getSrcTy(), Trunc.getType())) &&
505  "Don't narrow to an illegal scalar type");
506 
507  // First, find an or'd pair of opposite shifts with the same shifted operand:
508  // trunc (or (lshr ShVal, ShAmt0), (shl ShVal, ShAmt1))
509  Value *Or0, *Or1;
510  if (!match(Trunc.getOperand(0), m_OneUse(m_Or(m_Value(Or0), m_Value(Or1)))))
511  return nullptr;
512 
513  Value *ShVal, *ShAmt0, *ShAmt1;
514  if (!match(Or0, m_OneUse(m_LogicalShift(m_Value(ShVal), m_Value(ShAmt0)))) ||
515  !match(Or1, m_OneUse(m_LogicalShift(m_Specific(ShVal), m_Value(ShAmt1)))))
516  return nullptr;
517 
518  auto ShiftOpcode0 = cast<BinaryOperator>(Or0)->getOpcode();
519  auto ShiftOpcode1 = cast<BinaryOperator>(Or1)->getOpcode();
520  if (ShiftOpcode0 == ShiftOpcode1)
521  return nullptr;
522 
523  // The shift amounts must add up to the narrow bit width.
524  Value *ShAmt;
525  bool SubIsOnLHS;
526  Type *DestTy = Trunc.getType();
527  unsigned NarrowWidth = DestTy->getScalarSizeInBits();
528  if (match(ShAmt0,
529  m_OneUse(m_Sub(m_SpecificInt(NarrowWidth), m_Specific(ShAmt1))))) {
530  ShAmt = ShAmt1;
531  SubIsOnLHS = true;
532  } else if (match(ShAmt1, m_OneUse(m_Sub(m_SpecificInt(NarrowWidth),
533  m_Specific(ShAmt0))))) {
534  ShAmt = ShAmt0;
535  SubIsOnLHS = false;
536  } else {
537  return nullptr;
538  }
539 
540  // The shifted value must have high zeros in the wide type. Typically, this
541  // will be a zext, but it could also be the result of an 'and' or 'shift'.
542  unsigned WideWidth = Trunc.getSrcTy()->getScalarSizeInBits();
543  APInt HiBitMask = APInt::getHighBitsSet(WideWidth, WideWidth - NarrowWidth);
544  if (!MaskedValueIsZero(ShVal, HiBitMask, 0, &Trunc))
545  return nullptr;
546 
547  // We have an unnecessarily wide rotate!
548  // trunc (or (lshr ShVal, ShAmt), (shl ShVal, BitWidth - ShAmt))
549  // Narrow it down to eliminate the zext/trunc:
550  // or (lshr trunc(ShVal), ShAmt0'), (shl trunc(ShVal), ShAmt1')
551  Value *NarrowShAmt = Builder.CreateTrunc(ShAmt, DestTy);
552  Value *NegShAmt = Builder.CreateNeg(NarrowShAmt);
553 
554  // Mask both shift amounts to ensure there's no UB from oversized shifts.
555  Constant *MaskC = ConstantInt::get(DestTy, NarrowWidth - 1);
556  Value *MaskedShAmt = Builder.CreateAnd(NarrowShAmt, MaskC);
557  Value *MaskedNegShAmt = Builder.CreateAnd(NegShAmt, MaskC);
558 
559  // Truncate the original value and use narrow ops.
560  Value *X = Builder.CreateTrunc(ShVal, DestTy);
561  Value *NarrowShAmt0 = SubIsOnLHS ? MaskedNegShAmt : MaskedShAmt;
562  Value *NarrowShAmt1 = SubIsOnLHS ? MaskedShAmt : MaskedNegShAmt;
563  Value *NarrowSh0 = Builder.CreateBinOp(ShiftOpcode0, X, NarrowShAmt0);
564  Value *NarrowSh1 = Builder.CreateBinOp(ShiftOpcode1, X, NarrowShAmt1);
565  return BinaryOperator::CreateOr(NarrowSh0, NarrowSh1);
566 }
567 
568 /// Try to narrow the width of math or bitwise logic instructions by pulling a
569 /// truncate ahead of binary operators.
570 /// TODO: Transforms for truncated shifts should be moved into here.
571 Instruction *InstCombiner::narrowBinOp(TruncInst &Trunc) {
572  Type *SrcTy = Trunc.getSrcTy();
573  Type *DestTy = Trunc.getType();
574  if (!isa<VectorType>(SrcTy) && !shouldChangeType(SrcTy, DestTy))
575  return nullptr;
576 
577  BinaryOperator *BinOp;
578  if (!match(Trunc.getOperand(0), m_OneUse(m_BinOp(BinOp))))
579  return nullptr;
580 
581  Value *BinOp0 = BinOp->getOperand(0);
582  Value *BinOp1 = BinOp->getOperand(1);
583  switch (BinOp->getOpcode()) {
584  case Instruction::And:
585  case Instruction::Or:
586  case Instruction::Xor:
587  case Instruction::Add:
588  case Instruction::Sub:
589  case Instruction::Mul: {
590  Constant *C;
591  if (match(BinOp0, m_Constant(C))) {
592  // trunc (binop C, X) --> binop (trunc C', X)
593  Constant *NarrowC = ConstantExpr::getTrunc(C, DestTy);
594  Value *TruncX = Builder.CreateTrunc(BinOp1, DestTy);
595  return BinaryOperator::Create(BinOp->getOpcode(), NarrowC, TruncX);
596  }
597  if (match(BinOp1, m_Constant(C))) {
598  // trunc (binop X, C) --> binop (trunc X, C')
599  Constant *NarrowC = ConstantExpr::getTrunc(C, DestTy);
600  Value *TruncX = Builder.CreateTrunc(BinOp0, DestTy);
601  return BinaryOperator::Create(BinOp->getOpcode(), TruncX, NarrowC);
602  }
603  Value *X;
604  if (match(BinOp0, m_ZExtOrSExt(m_Value(X))) && X->getType() == DestTy) {
605  // trunc (binop (ext X), Y) --> binop X, (trunc Y)
606  Value *NarrowOp1 = Builder.CreateTrunc(BinOp1, DestTy);
607  return BinaryOperator::Create(BinOp->getOpcode(), X, NarrowOp1);
608  }
609  if (match(BinOp1, m_ZExtOrSExt(m_Value(X))) && X->getType() == DestTy) {
610  // trunc (binop Y, (ext X)) --> binop (trunc Y), X
611  Value *NarrowOp0 = Builder.CreateTrunc(BinOp0, DestTy);
612  return BinaryOperator::Create(BinOp->getOpcode(), NarrowOp0, X);
613  }
614  break;
615  }
616 
617  default: break;
618  }
619 
620  if (Instruction *NarrowOr = narrowRotate(Trunc))
621  return NarrowOr;
622 
623  return nullptr;
624 }
625 
626 /// Try to narrow the width of a splat shuffle. This could be generalized to any
627 /// shuffle with a constant operand, but we limit the transform to avoid
628 /// creating a shuffle type that targets may not be able to lower effectively.
630  InstCombiner::BuilderTy &Builder) {
631  auto *Shuf = dyn_cast<ShuffleVectorInst>(Trunc.getOperand(0));
632  if (Shuf && Shuf->hasOneUse() && isa<UndefValue>(Shuf->getOperand(1)) &&
633  Shuf->getMask()->getSplatValue() &&
634  Shuf->getType() == Shuf->getOperand(0)->getType()) {
635  // trunc (shuf X, Undef, SplatMask) --> shuf (trunc X), Undef, SplatMask
636  Constant *NarrowUndef = UndefValue::get(Trunc.getType());
637  Value *NarrowOp = Builder.CreateTrunc(Shuf->getOperand(0), Trunc.getType());
638  return new ShuffleVectorInst(NarrowOp, NarrowUndef, Shuf->getMask());
639  }
640 
641  return nullptr;
642 }
643 
644 /// Try to narrow the width of an insert element. This could be generalized for
645 /// any vector constant, but we limit the transform to insertion into undef to
646 /// avoid potential backend problems from unsupported insertion widths. This
647 /// could also be extended to handle the case of inserting a scalar constant
648 /// into a vector variable.
650  InstCombiner::BuilderTy &Builder) {
651  Instruction::CastOps Opcode = Trunc.getOpcode();
652  assert((Opcode == Instruction::Trunc || Opcode == Instruction::FPTrunc) &&
653  "Unexpected instruction for shrinking");
654 
655  auto *InsElt = dyn_cast<InsertElementInst>(Trunc.getOperand(0));
656  if (!InsElt || !InsElt->hasOneUse())
657  return nullptr;
658 
659  Type *DestTy = Trunc.getType();
660  Type *DestScalarTy = DestTy->getScalarType();
661  Value *VecOp = InsElt->getOperand(0);
662  Value *ScalarOp = InsElt->getOperand(1);
663  Value *Index = InsElt->getOperand(2);
664 
665  if (isa<UndefValue>(VecOp)) {
666  // trunc (inselt undef, X, Index) --> inselt undef, (trunc X), Index
667  // fptrunc (inselt undef, X, Index) --> inselt undef, (fptrunc X), Index
668  UndefValue *NarrowUndef = UndefValue::get(DestTy);
669  Value *NarrowOp = Builder.CreateCast(Opcode, ScalarOp, DestScalarTy);
670  return InsertElementInst::Create(NarrowUndef, NarrowOp, Index);
671  }
672 
673  return nullptr;
674 }
675 
677  if (Instruction *Result = commonCastTransforms(CI))
678  return Result;
679 
680  // Test if the trunc is the user of a select which is part of a
681  // minimum or maximum operation. If so, don't do any more simplification.
682  // Even simplifying demanded bits can break the canonical form of a
683  // min/max.
684  Value *LHS, *RHS;
685  if (SelectInst *SI = dyn_cast<SelectInst>(CI.getOperand(0)))
686  if (matchSelectPattern(SI, LHS, RHS).Flavor != SPF_UNKNOWN)
687  return nullptr;
688 
689  // See if we can simplify any instructions used by the input whose sole
690  // purpose is to compute bits we don't care about.
691  if (SimplifyDemandedInstructionBits(CI))
692  return &CI;
693 
694  Value *Src = CI.getOperand(0);
695  Type *DestTy = CI.getType(), *SrcTy = Src->getType();
696 
697  // Attempt to truncate the entire input expression tree to the destination
698  // type. Only do this if the dest type is a simple type, don't convert the
699  // expression tree to something weird like i93 unless the source is also
700  // strange.
701  if ((DestTy->isVectorTy() || shouldChangeType(SrcTy, DestTy)) &&
702  canEvaluateTruncated(Src, DestTy, *this, &CI)) {
703 
704  // If this cast is a truncate, evaluting in a different type always
705  // eliminates the cast, so it is always a win.
706  LLVM_DEBUG(
707  dbgs() << "ICE: EvaluateInDifferentType converting expression type"
708  " to avoid cast: "
709  << CI << '\n');
710  Value *Res = EvaluateInDifferentType(Src, DestTy, false);
711  assert(Res->getType() == DestTy);
712  return replaceInstUsesWith(CI, Res);
713  }
714 
715  // Canonicalize trunc x to i1 -> (icmp ne (and x, 1), 0), likewise for vector.
716  if (DestTy->getScalarSizeInBits() == 1) {
717  Constant *One = ConstantInt::get(SrcTy, 1);
718  Src = Builder.CreateAnd(Src, One);
719  Value *Zero = Constant::getNullValue(Src->getType());
720  return new ICmpInst(ICmpInst::ICMP_NE, Src, Zero);
721  }
722 
723  // FIXME: Maybe combine the next two transforms to handle the no cast case
724  // more efficiently. Support vector types. Cleanup code by using m_OneUse.
725 
726  // Transform trunc(lshr (zext A), Cst) to eliminate one type conversion.
727  Value *A = nullptr; ConstantInt *Cst = nullptr;
728  if (Src->hasOneUse() &&
729  match(Src, m_LShr(m_ZExt(m_Value(A)), m_ConstantInt(Cst)))) {
730  // We have three types to worry about here, the type of A, the source of
731  // the truncate (MidSize), and the destination of the truncate. We know that
732  // ASize < MidSize and MidSize > ResultSize, but don't know the relation
733  // between ASize and ResultSize.
734  unsigned ASize = A->getType()->getPrimitiveSizeInBits();
735 
736  // If the shift amount is larger than the size of A, then the result is
737  // known to be zero because all the input bits got shifted out.
738  if (Cst->getZExtValue() >= ASize)
739  return replaceInstUsesWith(CI, Constant::getNullValue(DestTy));
740 
741  // Since we're doing an lshr and a zero extend, and know that the shift
742  // amount is smaller than ASize, it is always safe to do the shift in A's
743  // type, then zero extend or truncate to the result.
744  Value *Shift = Builder.CreateLShr(A, Cst->getZExtValue());
745  Shift->takeName(Src);
746  return CastInst::CreateIntegerCast(Shift, DestTy, false);
747  }
748 
749  // FIXME: We should canonicalize to zext/trunc and remove this transform.
750  // Transform trunc(lshr (sext A), Cst) to ashr A, Cst to eliminate type
751  // conversion.
752  // It works because bits coming from sign extension have the same value as
753  // the sign bit of the original value; performing ashr instead of lshr
754  // generates bits of the same value as the sign bit.
755  if (Src->hasOneUse() &&
756  match(Src, m_LShr(m_SExt(m_Value(A)), m_ConstantInt(Cst)))) {
757  Value *SExt = cast<Instruction>(Src)->getOperand(0);
758  const unsigned SExtSize = SExt->getType()->getPrimitiveSizeInBits();
759  const unsigned ASize = A->getType()->getPrimitiveSizeInBits();
760  const unsigned CISize = CI.getType()->getPrimitiveSizeInBits();
761  const unsigned MaxAmt = SExtSize - std::max(CISize, ASize);
762  unsigned ShiftAmt = Cst->getZExtValue();
763 
764  // This optimization can be only performed when zero bits generated by
765  // the original lshr aren't pulled into the value after truncation, so we
766  // can only shift by values no larger than the number of extension bits.
767  // FIXME: Instead of bailing when the shift is too large, use and to clear
768  // the extra bits.
769  if (ShiftAmt <= MaxAmt) {
770  if (CISize == ASize)
771  return BinaryOperator::CreateAShr(A, ConstantInt::get(CI.getType(),
772  std::min(ShiftAmt, ASize - 1)));
773  if (SExt->hasOneUse()) {
774  Value *Shift = Builder.CreateAShr(A, std::min(ShiftAmt, ASize - 1));
775  Shift->takeName(Src);
776  return CastInst::CreateIntegerCast(Shift, CI.getType(), true);
777  }
778  }
779  }
780 
781  if (Instruction *I = narrowBinOp(CI))
782  return I;
783 
784  if (Instruction *I = shrinkSplatShuffle(CI, Builder))
785  return I;
786 
787  if (Instruction *I = shrinkInsertElt(CI, Builder))
788  return I;
789 
790  if (Src->hasOneUse() && isa<IntegerType>(SrcTy) &&
791  shouldChangeType(SrcTy, DestTy)) {
792  // Transform "trunc (shl X, cst)" -> "shl (trunc X), cst" so long as the
793  // dest type is native and cst < dest size.
794  if (match(Src, m_Shl(m_Value(A), m_ConstantInt(Cst))) &&
795  !match(A, m_Shr(m_Value(), m_Constant()))) {
796  // Skip shifts of shift by constants. It undoes a combine in
797  // FoldShiftByConstant and is the extend in reg pattern.
798  const unsigned DestSize = DestTy->getScalarSizeInBits();
799  if (Cst->getValue().ult(DestSize)) {
800  Value *NewTrunc = Builder.CreateTrunc(A, DestTy, A->getName() + ".tr");
801 
802  return BinaryOperator::Create(
803  Instruction::Shl, NewTrunc,
804  ConstantInt::get(DestTy, Cst->getValue().trunc(DestSize)));
805  }
806  }
807  }
808 
809  if (Instruction *I = foldVecTruncToExtElt(CI, *this))
810  return I;
811 
812  return nullptr;
813 }
814 
815 Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, ZExtInst &CI,
816  bool DoTransform) {
817  // If we are just checking for a icmp eq of a single bit and zext'ing it
818  // to an integer, then shift the bit to the appropriate place and then
819  // cast to integer to avoid the comparison.
820  const APInt *Op1CV;
821  if (match(ICI->getOperand(1), m_APInt(Op1CV))) {
822 
823  // zext (x <s 0) to i32 --> x>>u31 true if signbit set.
824  // zext (x >s -1) to i32 --> (x>>u31)^1 true if signbit clear.
825  if ((ICI->getPredicate() == ICmpInst::ICMP_SLT && Op1CV->isNullValue()) ||
826  (ICI->getPredicate() == ICmpInst::ICMP_SGT && Op1CV->isAllOnesValue())) {
827  if (!DoTransform) return ICI;
828 
829  Value *In = ICI->getOperand(0);
830  Value *Sh = ConstantInt::get(In->getType(),
831  In->getType()->getScalarSizeInBits() - 1);
832  In = Builder.CreateLShr(In, Sh, In->getName() + ".lobit");
833  if (In->getType() != CI.getType())
834  In = Builder.CreateIntCast(In, CI.getType(), false /*ZExt*/);
835 
836  if (ICI->getPredicate() == ICmpInst::ICMP_SGT) {
837  Constant *One = ConstantInt::get(In->getType(), 1);
838  In = Builder.CreateXor(In, One, In->getName() + ".not");
839  }
840 
841  return replaceInstUsesWith(CI, In);
842  }
843 
844  // zext (X == 0) to i32 --> X^1 iff X has only the low bit set.
845  // zext (X == 0) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
846  // zext (X == 1) to i32 --> X iff X has only the low bit set.
847  // zext (X == 2) to i32 --> X>>1 iff X has only the 2nd bit set.
848  // zext (X != 0) to i32 --> X iff X has only the low bit set.
849  // zext (X != 0) to i32 --> X>>1 iff X has only the 2nd bit set.
850  // zext (X != 1) to i32 --> X^1 iff X has only the low bit set.
851  // zext (X != 2) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
852  if ((Op1CV->isNullValue() || Op1CV->isPowerOf2()) &&
853  // This only works for EQ and NE
854  ICI->isEquality()) {
855  // If Op1C some other power of two, convert:
856  KnownBits Known = computeKnownBits(ICI->getOperand(0), 0, &CI);
857 
858  APInt KnownZeroMask(~Known.Zero);
859  if (KnownZeroMask.isPowerOf2()) { // Exactly 1 possible 1?
860  if (!DoTransform) return ICI;
861 
862  bool isNE = ICI->getPredicate() == ICmpInst::ICMP_NE;
863  if (!Op1CV->isNullValue() && (*Op1CV != KnownZeroMask)) {
864  // (X&4) == 2 --> false
865  // (X&4) != 2 --> true
866  Constant *Res = ConstantInt::get(CI.getType(), isNE);
867  return replaceInstUsesWith(CI, Res);
868  }
869 
870  uint32_t ShAmt = KnownZeroMask.logBase2();
871  Value *In = ICI->getOperand(0);
872  if (ShAmt) {
873  // Perform a logical shr by shiftamt.
874  // Insert the shift to put the result in the low bit.
875  In = Builder.CreateLShr(In, ConstantInt::get(In->getType(), ShAmt),
876  In->getName() + ".lobit");
877  }
878 
879  if (!Op1CV->isNullValue() == isNE) { // Toggle the low bit.
880  Constant *One = ConstantInt::get(In->getType(), 1);
881  In = Builder.CreateXor(In, One);
882  }
883 
884  if (CI.getType() == In->getType())
885  return replaceInstUsesWith(CI, In);
886 
887  Value *IntCast = Builder.CreateIntCast(In, CI.getType(), false);
888  return replaceInstUsesWith(CI, IntCast);
889  }
890  }
891  }
892 
893  // icmp ne A, B is equal to xor A, B when A and B only really have one bit.
894  // It is also profitable to transform icmp eq into not(xor(A, B)) because that
895  // may lead to additional simplifications.
896  if (ICI->isEquality() && CI.getType() == ICI->getOperand(0)->getType()) {
897  if (IntegerType *ITy = dyn_cast<IntegerType>(CI.getType())) {
898  Value *LHS = ICI->getOperand(0);
899  Value *RHS = ICI->getOperand(1);
900 
901  KnownBits KnownLHS = computeKnownBits(LHS, 0, &CI);
902  KnownBits KnownRHS = computeKnownBits(RHS, 0, &CI);
903 
904  if (KnownLHS.Zero == KnownRHS.Zero && KnownLHS.One == KnownRHS.One) {
905  APInt KnownBits = KnownLHS.Zero | KnownLHS.One;
906  APInt UnknownBit = ~KnownBits;
907  if (UnknownBit.countPopulation() == 1) {
908  if (!DoTransform) return ICI;
909 
910  Value *Result = Builder.CreateXor(LHS, RHS);
911 
912  // Mask off any bits that are set and won't be shifted away.
913  if (KnownLHS.One.uge(UnknownBit))
914  Result = Builder.CreateAnd(Result,
915  ConstantInt::get(ITy, UnknownBit));
916 
917  // Shift the bit we're testing down to the lsb.
918  Result = Builder.CreateLShr(
919  Result, ConstantInt::get(ITy, UnknownBit.countTrailingZeros()));
920 
921  if (ICI->getPredicate() == ICmpInst::ICMP_EQ)
922  Result = Builder.CreateXor(Result, ConstantInt::get(ITy, 1));
923  Result->takeName(ICI);
924  return replaceInstUsesWith(CI, Result);
925  }
926  }
927  }
928  }
929 
930  return nullptr;
931 }
932 
933 /// Determine if the specified value can be computed in the specified wider type
934 /// and produce the same low bits. If not, return false.
935 ///
936 /// If this function returns true, it can also return a non-zero number of bits
937 /// (in BitsToClear) which indicates that the value it computes is correct for
938 /// the zero extend, but that the additional BitsToClear bits need to be zero'd
939 /// out. For example, to promote something like:
940 ///
941 /// %B = trunc i64 %A to i32
942 /// %C = lshr i32 %B, 8
943 /// %E = zext i32 %C to i64
944 ///
945 /// CanEvaluateZExtd for the 'lshr' will return true, and BitsToClear will be
946 /// set to 8 to indicate that the promoted value needs to have bits 24-31
947 /// cleared in addition to bits 32-63. Since an 'and' will be generated to
948 /// clear the top bits anyway, doing this has no extra cost.
949 ///
950 /// This function works on both vectors and scalars.
951 static bool canEvaluateZExtd(Value *V, Type *Ty, unsigned &BitsToClear,
952  InstCombiner &IC, Instruction *CxtI) {
953  BitsToClear = 0;
954  if (canAlwaysEvaluateInType(V, Ty))
955  return true;
956  if (canNotEvaluateInType(V, Ty))
957  return false;
958 
959  auto *I = cast<Instruction>(V);
960  unsigned Tmp;
961  switch (I->getOpcode()) {
962  case Instruction::ZExt: // zext(zext(x)) -> zext(x).
963  case Instruction::SExt: // zext(sext(x)) -> sext(x).
964  case Instruction::Trunc: // zext(trunc(x)) -> trunc(x) or zext(x)
965  return true;
966  case Instruction::And:
967  case Instruction::Or:
968  case Instruction::Xor:
969  case Instruction::Add:
970  case Instruction::Sub:
971  case Instruction::Mul:
972  if (!canEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI) ||
973  !canEvaluateZExtd(I->getOperand(1), Ty, Tmp, IC, CxtI))
974  return false;
975  // These can all be promoted if neither operand has 'bits to clear'.
976  if (BitsToClear == 0 && Tmp == 0)
977  return true;
978 
979  // If the operation is an AND/OR/XOR and the bits to clear are zero in the
980  // other side, BitsToClear is ok.
981  if (Tmp == 0 && I->isBitwiseLogicOp()) {
982  // We use MaskedValueIsZero here for generality, but the case we care
983  // about the most is constant RHS.
984  unsigned VSize = V->getType()->getScalarSizeInBits();
985  if (IC.MaskedValueIsZero(I->getOperand(1),
986  APInt::getHighBitsSet(VSize, BitsToClear),
987  0, CxtI)) {
988  // If this is an And instruction and all of the BitsToClear are
989  // known to be zero we can reset BitsToClear.
990  if (I->getOpcode() == Instruction::And)
991  BitsToClear = 0;
992  return true;
993  }
994  }
995 
996  // Otherwise, we don't know how to analyze this BitsToClear case yet.
997  return false;
998 
999  case Instruction::Shl: {
1000  // We can promote shl(x, cst) if we can promote x. Since shl overwrites the
1001  // upper bits we can reduce BitsToClear by the shift amount.
1002  const APInt *Amt;
1003  if (match(I->getOperand(1), m_APInt(Amt))) {
1004  if (!canEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI))
1005  return false;
1006  uint64_t ShiftAmt = Amt->getZExtValue();
1007  BitsToClear = ShiftAmt < BitsToClear ? BitsToClear - ShiftAmt : 0;
1008  return true;
1009  }
1010  return false;
1011  }
1012  case Instruction::LShr: {
1013  // We can promote lshr(x, cst) if we can promote x. This requires the
1014  // ultimate 'and' to clear out the high zero bits we're clearing out though.
1015  const APInt *Amt;
1016  if (match(I->getOperand(1), m_APInt(Amt))) {
1017  if (!canEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI))
1018  return false;
1019  BitsToClear += Amt->getZExtValue();
1020  if (BitsToClear > V->getType()->getScalarSizeInBits())
1021  BitsToClear = V->getType()->getScalarSizeInBits();
1022  return true;
1023  }
1024  // Cannot promote variable LSHR.
1025  return false;
1026  }
1027  case Instruction::Select:
1028  if (!canEvaluateZExtd(I->getOperand(1), Ty, Tmp, IC, CxtI) ||
1029  !canEvaluateZExtd(I->getOperand(2), Ty, BitsToClear, IC, CxtI) ||
1030  // TODO: If important, we could handle the case when the BitsToClear are
1031  // known zero in the disagreeing side.
1032  Tmp != BitsToClear)
1033  return false;
1034  return true;
1035 
1036  case Instruction::PHI: {
1037  // We can change a phi if we can change all operands. Note that we never
1038  // get into trouble with cyclic PHIs here because we only consider
1039  // instructions with a single use.
1040  PHINode *PN = cast<PHINode>(I);
1041  if (!canEvaluateZExtd(PN->getIncomingValue(0), Ty, BitsToClear, IC, CxtI))
1042  return false;
1043  for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i)
1044  if (!canEvaluateZExtd(PN->getIncomingValue(i), Ty, Tmp, IC, CxtI) ||
1045  // TODO: If important, we could handle the case when the BitsToClear
1046  // are known zero in the disagreeing input.
1047  Tmp != BitsToClear)
1048  return false;
1049  return true;
1050  }
1051  default:
1052  // TODO: Can handle more cases here.
1053  return false;
1054  }
1055 }
1056 
1058  // If this zero extend is only used by a truncate, let the truncate be
1059  // eliminated before we try to optimize this zext.
1060  if (CI.hasOneUse() && isa<TruncInst>(CI.user_back()))
1061  return nullptr;
1062 
1063  // If one of the common conversion will work, do it.
1064  if (Instruction *Result = commonCastTransforms(CI))
1065  return Result;
1066 
1067  Value *Src = CI.getOperand(0);
1068  Type *SrcTy = Src->getType(), *DestTy = CI.getType();
1069 
1070  // Attempt to extend the entire input expression tree to the destination
1071  // type. Only do this if the dest type is a simple type, don't convert the
1072  // expression tree to something weird like i93 unless the source is also
1073  // strange.
1074  unsigned BitsToClear;
1075  if ((DestTy->isVectorTy() || shouldChangeType(SrcTy, DestTy)) &&
1076  canEvaluateZExtd(Src, DestTy, BitsToClear, *this, &CI)) {
1077  assert(BitsToClear <= SrcTy->getScalarSizeInBits() &&
1078  "Can't clear more bits than in SrcTy");
1079 
1080  // Okay, we can transform this! Insert the new expression now.
1081  LLVM_DEBUG(
1082  dbgs() << "ICE: EvaluateInDifferentType converting expression type"
1083  " to avoid zero extend: "
1084  << CI << '\n');
1085  Value *Res = EvaluateInDifferentType(Src, DestTy, false);
1086  assert(Res->getType() == DestTy);
1087 
1088  uint32_t SrcBitsKept = SrcTy->getScalarSizeInBits()-BitsToClear;
1089  uint32_t DestBitSize = DestTy->getScalarSizeInBits();
1090 
1091  // If the high bits are already filled with zeros, just replace this
1092  // cast with the result.
1093  if (MaskedValueIsZero(Res,
1094  APInt::getHighBitsSet(DestBitSize,
1095  DestBitSize-SrcBitsKept),
1096  0, &CI))
1097  return replaceInstUsesWith(CI, Res);
1098 
1099  // We need to emit an AND to clear the high bits.
1100  Constant *C = ConstantInt::get(Res->getType(),
1101  APInt::getLowBitsSet(DestBitSize, SrcBitsKept));
1102  return BinaryOperator::CreateAnd(Res, C);
1103  }
1104 
1105  // If this is a TRUNC followed by a ZEXT then we are dealing with integral
1106  // types and if the sizes are just right we can convert this into a logical
1107  // 'and' which will be much cheaper than the pair of casts.
1108  if (TruncInst *CSrc = dyn_cast<TruncInst>(Src)) { // A->B->C cast
1109  // TODO: Subsume this into EvaluateInDifferentType.
1110 
1111  // Get the sizes of the types involved. We know that the intermediate type
1112  // will be smaller than A or C, but don't know the relation between A and C.
1113  Value *A = CSrc->getOperand(0);
1114  unsigned SrcSize = A->getType()->getScalarSizeInBits();
1115  unsigned MidSize = CSrc->getType()->getScalarSizeInBits();
1116  unsigned DstSize = CI.getType()->getScalarSizeInBits();
1117  // If we're actually extending zero bits, then if
1118  // SrcSize < DstSize: zext(a & mask)
1119  // SrcSize == DstSize: a & mask
1120  // SrcSize > DstSize: trunc(a) & mask
1121  if (SrcSize < DstSize) {
1122  APInt AndValue(APInt::getLowBitsSet(SrcSize, MidSize));
1123  Constant *AndConst = ConstantInt::get(A->getType(), AndValue);
1124  Value *And = Builder.CreateAnd(A, AndConst, CSrc->getName() + ".mask");
1125  return new ZExtInst(And, CI.getType());
1126  }
1127 
1128  if (SrcSize == DstSize) {
1129  APInt AndValue(APInt::getLowBitsSet(SrcSize, MidSize));
1130  return BinaryOperator::CreateAnd(A, ConstantInt::get(A->getType(),
1131  AndValue));
1132  }
1133  if (SrcSize > DstSize) {
1134  Value *Trunc = Builder.CreateTrunc(A, CI.getType());
1135  APInt AndValue(APInt::getLowBitsSet(DstSize, MidSize));
1136  return BinaryOperator::CreateAnd(Trunc,
1137  ConstantInt::get(Trunc->getType(),
1138  AndValue));
1139  }
1140  }
1141 
1142  if (ICmpInst *ICI = dyn_cast<ICmpInst>(Src))
1143  return transformZExtICmp(ICI, CI);
1144 
1145  BinaryOperator *SrcI = dyn_cast<BinaryOperator>(Src);
1146  if (SrcI && SrcI->getOpcode() == Instruction::Or) {
1147  // zext (or icmp, icmp) -> or (zext icmp), (zext icmp) if at least one
1148  // of the (zext icmp) can be eliminated. If so, immediately perform the
1149  // according elimination.
1150  ICmpInst *LHS = dyn_cast<ICmpInst>(SrcI->getOperand(0));
1151  ICmpInst *RHS = dyn_cast<ICmpInst>(SrcI->getOperand(1));
1152  if (LHS && RHS && LHS->hasOneUse() && RHS->hasOneUse() &&
1153  (transformZExtICmp(LHS, CI, false) ||
1154  transformZExtICmp(RHS, CI, false))) {
1155  // zext (or icmp, icmp) -> or (zext icmp), (zext icmp)
1156  Value *LCast = Builder.CreateZExt(LHS, CI.getType(), LHS->getName());
1157  Value *RCast = Builder.CreateZExt(RHS, CI.getType(), RHS->getName());
1158  BinaryOperator *Or = BinaryOperator::Create(Instruction::Or, LCast, RCast);
1159 
1160  // Perform the elimination.
1161  if (auto *LZExt = dyn_cast<ZExtInst>(LCast))
1162  transformZExtICmp(LHS, *LZExt);
1163  if (auto *RZExt = dyn_cast<ZExtInst>(RCast))
1164  transformZExtICmp(RHS, *RZExt);
1165 
1166  return Or;
1167  }
1168  }
1169 
1170  // zext(trunc(X) & C) -> (X & zext(C)).
1171  Constant *C;
1172  Value *X;
1173  if (SrcI &&
1174  match(SrcI, m_OneUse(m_And(m_Trunc(m_Value(X)), m_Constant(C)))) &&
1175  X->getType() == CI.getType())
1176  return BinaryOperator::CreateAnd(X, ConstantExpr::getZExt(C, CI.getType()));
1177 
1178  // zext((trunc(X) & C) ^ C) -> ((X & zext(C)) ^ zext(C)).
1179  Value *And;
1180  if (SrcI && match(SrcI, m_OneUse(m_Xor(m_Value(And), m_Constant(C)))) &&
1181  match(And, m_OneUse(m_And(m_Trunc(m_Value(X)), m_Specific(C)))) &&
1182  X->getType() == CI.getType()) {
1183  Constant *ZC = ConstantExpr::getZExt(C, CI.getType());
1184  return BinaryOperator::CreateXor(Builder.CreateAnd(X, ZC), ZC);
1185  }
1186 
1187  return nullptr;
1188 }
1189 
1190 /// Transform (sext icmp) to bitwise / integer operations to eliminate the icmp.
1191 Instruction *InstCombiner::transformSExtICmp(ICmpInst *ICI, Instruction &CI) {
1192  Value *Op0 = ICI->getOperand(0), *Op1 = ICI->getOperand(1);
1193  ICmpInst::Predicate Pred = ICI->getPredicate();
1194 
1195  // Don't bother if Op1 isn't of vector or integer type.
1196  if (!Op1->getType()->isIntOrIntVectorTy())
1197  return nullptr;
1198 
1199  if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
1200  // (x <s 0) ? -1 : 0 -> ashr x, 31 -> all ones if negative
1201  // (x >s -1) ? -1 : 0 -> not (ashr x, 31) -> all ones if positive
1202  if ((Pred == ICmpInst::ICMP_SLT && Op1C->isNullValue()) ||
1203  (Pred == ICmpInst::ICMP_SGT && Op1C->isAllOnesValue())) {
1204 
1205  Value *Sh = ConstantInt::get(Op0->getType(),
1206  Op0->getType()->getScalarSizeInBits()-1);
1207  Value *In = Builder.CreateAShr(Op0, Sh, Op0->getName() + ".lobit");
1208  if (In->getType() != CI.getType())
1209  In = Builder.CreateIntCast(In, CI.getType(), true /*SExt*/);
1210 
1211  if (Pred == ICmpInst::ICMP_SGT)
1212  In = Builder.CreateNot(In, In->getName() + ".not");
1213  return replaceInstUsesWith(CI, In);
1214  }
1215  }
1216 
1217  if (ConstantInt *Op1C = dyn_cast<ConstantInt>(Op1)) {
1218  // If we know that only one bit of the LHS of the icmp can be set and we
1219  // have an equality comparison with zero or a power of 2, we can transform
1220  // the icmp and sext into bitwise/integer operations.
1221  if (ICI->hasOneUse() &&
1222  ICI->isEquality() && (Op1C->isZero() || Op1C->getValue().isPowerOf2())){
1223  KnownBits Known = computeKnownBits(Op0, 0, &CI);
1224 
1225  APInt KnownZeroMask(~Known.Zero);
1226  if (KnownZeroMask.isPowerOf2()) {
1227  Value *In = ICI->getOperand(0);
1228 
1229  // If the icmp tests for a known zero bit we can constant fold it.
1230  if (!Op1C->isZero() && Op1C->getValue() != KnownZeroMask) {
1231  Value *V = Pred == ICmpInst::ICMP_NE ?
1234  return replaceInstUsesWith(CI, V);
1235  }
1236 
1237  if (!Op1C->isZero() == (Pred == ICmpInst::ICMP_NE)) {
1238  // sext ((x & 2^n) == 0) -> (x >> n) - 1
1239  // sext ((x & 2^n) != 2^n) -> (x >> n) - 1
1240  unsigned ShiftAmt = KnownZeroMask.countTrailingZeros();
1241  // Perform a right shift to place the desired bit in the LSB.
1242  if (ShiftAmt)
1243  In = Builder.CreateLShr(In,
1244  ConstantInt::get(In->getType(), ShiftAmt));
1245 
1246  // At this point "In" is either 1 or 0. Subtract 1 to turn
1247  // {1, 0} -> {0, -1}.
1248  In = Builder.CreateAdd(In,
1250  "sext");
1251  } else {
1252  // sext ((x & 2^n) != 0) -> (x << bitwidth-n) a>> bitwidth-1
1253  // sext ((x & 2^n) == 2^n) -> (x << bitwidth-n) a>> bitwidth-1
1254  unsigned ShiftAmt = KnownZeroMask.countLeadingZeros();
1255  // Perform a left shift to place the desired bit in the MSB.
1256  if (ShiftAmt)
1257  In = Builder.CreateShl(In,
1258  ConstantInt::get(In->getType(), ShiftAmt));
1259 
1260  // Distribute the bit over the whole bit width.
1261  In = Builder.CreateAShr(In, ConstantInt::get(In->getType(),
1262  KnownZeroMask.getBitWidth() - 1), "sext");
1263  }
1264 
1265  if (CI.getType() == In->getType())
1266  return replaceInstUsesWith(CI, In);
1267  return CastInst::CreateIntegerCast(In, CI.getType(), true/*SExt*/);
1268  }
1269  }
1270  }
1271 
1272  return nullptr;
1273 }
1274 
1275 /// Return true if we can take the specified value and return it as type Ty
1276 /// without inserting any new casts and without changing the value of the common
1277 /// low bits. This is used by code that tries to promote integer operations to
1278 /// a wider types will allow us to eliminate the extension.
1279 ///
1280 /// This function works on both vectors and scalars.
1281 ///
1282 static bool canEvaluateSExtd(Value *V, Type *Ty) {
1284  "Can't sign extend type to a smaller type");
1285  if (canAlwaysEvaluateInType(V, Ty))
1286  return true;
1287  if (canNotEvaluateInType(V, Ty))
1288  return false;
1289 
1290  auto *I = cast<Instruction>(V);
1291  switch (I->getOpcode()) {
1292  case Instruction::SExt: // sext(sext(x)) -> sext(x)
1293  case Instruction::ZExt: // sext(zext(x)) -> zext(x)
1294  case Instruction::Trunc: // sext(trunc(x)) -> trunc(x) or sext(x)
1295  return true;
1296  case Instruction::And:
1297  case Instruction::Or:
1298  case Instruction::Xor:
1299  case Instruction::Add:
1300  case Instruction::Sub:
1301  case Instruction::Mul:
1302  // These operators can all arbitrarily be extended if their inputs can.
1303  return canEvaluateSExtd(I->getOperand(0), Ty) &&
1304  canEvaluateSExtd(I->getOperand(1), Ty);
1305 
1306  //case Instruction::Shl: TODO
1307  //case Instruction::LShr: TODO
1308 
1309  case Instruction::Select:
1310  return canEvaluateSExtd(I->getOperand(1), Ty) &&
1311  canEvaluateSExtd(I->getOperand(2), Ty);
1312 
1313  case Instruction::PHI: {
1314  // We can change a phi if we can change all operands. Note that we never
1315  // get into trouble with cyclic PHIs here because we only consider
1316  // instructions with a single use.
1317  PHINode *PN = cast<PHINode>(I);
1318  for (Value *IncValue : PN->incoming_values())
1319  if (!canEvaluateSExtd(IncValue, Ty)) return false;
1320  return true;
1321  }
1322  default:
1323  // TODO: Can handle more cases here.
1324  break;
1325  }
1326 
1327  return false;
1328 }
1329 
1331  // If this sign extend is only used by a truncate, let the truncate be
1332  // eliminated before we try to optimize this sext.
1333  if (CI.hasOneUse() && isa<TruncInst>(CI.user_back()))
1334  return nullptr;
1335 
1336  if (Instruction *I = commonCastTransforms(CI))
1337  return I;
1338 
1339  Value *Src = CI.getOperand(0);
1340  Type *SrcTy = Src->getType(), *DestTy = CI.getType();
1341 
1342  // If we know that the value being extended is positive, we can use a zext
1343  // instead.
1344  KnownBits Known = computeKnownBits(Src, 0, &CI);
1345  if (Known.isNonNegative()) {
1346  Value *ZExt = Builder.CreateZExt(Src, DestTy);
1347  return replaceInstUsesWith(CI, ZExt);
1348  }
1349 
1350  // Attempt to extend the entire input expression tree to the destination
1351  // type. Only do this if the dest type is a simple type, don't convert the
1352  // expression tree to something weird like i93 unless the source is also
1353  // strange.
1354  if ((DestTy->isVectorTy() || shouldChangeType(SrcTy, DestTy)) &&
1355  canEvaluateSExtd(Src, DestTy)) {
1356  // Okay, we can transform this! Insert the new expression now.
1357  LLVM_DEBUG(
1358  dbgs() << "ICE: EvaluateInDifferentType converting expression type"
1359  " to avoid sign extend: "
1360  << CI << '\n');
1361  Value *Res = EvaluateInDifferentType(Src, DestTy, true);
1362  assert(Res->getType() == DestTy);
1363 
1364  uint32_t SrcBitSize = SrcTy->getScalarSizeInBits();
1365  uint32_t DestBitSize = DestTy->getScalarSizeInBits();
1366 
1367  // If the high bits are already filled with sign bit, just replace this
1368  // cast with the result.
1369  if (ComputeNumSignBits(Res, 0, &CI) > DestBitSize - SrcBitSize)
1370  return replaceInstUsesWith(CI, Res);
1371 
1372  // We need to emit a shl + ashr to do the sign extend.
1373  Value *ShAmt = ConstantInt::get(DestTy, DestBitSize-SrcBitSize);
1374  return BinaryOperator::CreateAShr(Builder.CreateShl(Res, ShAmt, "sext"),
1375  ShAmt);
1376  }
1377 
1378  // If the input is a trunc from the destination type, then turn sext(trunc(x))
1379  // into shifts.
1380  Value *X;
1381  if (match(Src, m_OneUse(m_Trunc(m_Value(X)))) && X->getType() == DestTy) {
1382  // sext(trunc(X)) --> ashr(shl(X, C), C)
1383  unsigned SrcBitSize = SrcTy->getScalarSizeInBits();
1384  unsigned DestBitSize = DestTy->getScalarSizeInBits();
1385  Constant *ShAmt = ConstantInt::get(DestTy, DestBitSize - SrcBitSize);
1386  return BinaryOperator::CreateAShr(Builder.CreateShl(X, ShAmt), ShAmt);
1387  }
1388 
1389  if (ICmpInst *ICI = dyn_cast<ICmpInst>(Src))
1390  return transformSExtICmp(ICI, CI);
1391 
1392  // If the input is a shl/ashr pair of a same constant, then this is a sign
1393  // extension from a smaller value. If we could trust arbitrary bitwidth
1394  // integers, we could turn this into a truncate to the smaller bit and then
1395  // use a sext for the whole extension. Since we don't, look deeper and check
1396  // for a truncate. If the source and dest are the same type, eliminate the
1397  // trunc and extend and just do shifts. For example, turn:
1398  // %a = trunc i32 %i to i8
1399  // %b = shl i8 %a, 6
1400  // %c = ashr i8 %b, 6
1401  // %d = sext i8 %c to i32
1402  // into:
1403  // %a = shl i32 %i, 30
1404  // %d = ashr i32 %a, 30
1405  Value *A = nullptr;
1406  // TODO: Eventually this could be subsumed by EvaluateInDifferentType.
1407  ConstantInt *BA = nullptr, *CA = nullptr;
1408  if (match(Src, m_AShr(m_Shl(m_Trunc(m_Value(A)), m_ConstantInt(BA)),
1409  m_ConstantInt(CA))) &&
1410  BA == CA && A->getType() == CI.getType()) {
1411  unsigned MidSize = Src->getType()->getScalarSizeInBits();
1412  unsigned SrcDstSize = CI.getType()->getScalarSizeInBits();
1413  unsigned ShAmt = CA->getZExtValue()+SrcDstSize-MidSize;
1414  Constant *ShAmtV = ConstantInt::get(CI.getType(), ShAmt);
1415  A = Builder.CreateShl(A, ShAmtV, CI.getName());
1416  return BinaryOperator::CreateAShr(A, ShAmtV);
1417  }
1418 
1419  return nullptr;
1420 }
1421 
1422 
1423 /// Return a Constant* for the specified floating-point constant if it fits
1424 /// in the specified FP type without changing its value.
1425 static bool fitsInFPType(ConstantFP *CFP, const fltSemantics &Sem) {
1426  bool losesInfo;
1427  APFloat F = CFP->getValueAPF();
1428  (void)F.convert(Sem, APFloat::rmNearestTiesToEven, &losesInfo);
1429  return !losesInfo;
1430 }
1431 
1433  if (CFP->getType() == Type::getPPC_FP128Ty(CFP->getContext()))
1434  return nullptr; // No constant folding of this.
1435  // See if the value can be truncated to half and then reextended.
1436  if (fitsInFPType(CFP, APFloat::IEEEhalf()))
1437  return Type::getHalfTy(CFP->getContext());
1438  // See if the value can be truncated to float and then reextended.
1439  if (fitsInFPType(CFP, APFloat::IEEEsingle()))
1440  return Type::getFloatTy(CFP->getContext());
1441  if (CFP->getType()->isDoubleTy())
1442  return nullptr; // Won't shrink.
1443  if (fitsInFPType(CFP, APFloat::IEEEdouble()))
1444  return Type::getDoubleTy(CFP->getContext());
1445  // Don't try to shrink to various long double types.
1446  return nullptr;
1447 }
1448 
1449 // Determine if this is a vector of ConstantFPs and if so, return the minimal
1450 // type we can safely truncate all elements to.
1451 // TODO: Make these support undef elements.
1453  auto *CV = dyn_cast<Constant>(V);
1454  if (!CV || !CV->getType()->isVectorTy())
1455  return nullptr;
1456 
1457  Type *MinType = nullptr;
1458 
1459  unsigned NumElts = CV->getType()->getVectorNumElements();
1460  for (unsigned i = 0; i != NumElts; ++i) {
1461  auto *CFP = dyn_cast_or_null<ConstantFP>(CV->getAggregateElement(i));
1462  if (!CFP)
1463  return nullptr;
1464 
1465  Type *T = shrinkFPConstant(CFP);
1466  if (!T)
1467  return nullptr;
1468 
1469  // If we haven't found a type yet or this type has a larger mantissa than
1470  // our previous type, this is our new minimal type.
1471  if (!MinType || T->getFPMantissaWidth() > MinType->getFPMantissaWidth())
1472  MinType = T;
1473  }
1474 
1475  // Make a vector type from the minimal type.
1476  return VectorType::get(MinType, NumElts);
1477 }
1478 
1479 /// Find the minimum FP type we can safely truncate to.
1481  if (auto *FPExt = dyn_cast<FPExtInst>(V))
1482  return FPExt->getOperand(0)->getType();
1483 
1484  // If this value is a constant, return the constant in the smallest FP type
1485  // that can accurately represent it. This allows us to turn
1486  // (float)((double)X+2.0) into x+2.0f.
1487  if (auto *CFP = dyn_cast<ConstantFP>(V))
1488  if (Type *T = shrinkFPConstant(CFP))
1489  return T;
1490 
1491  // Try to shrink a vector of FP constants.
1492  if (Type *T = shrinkFPConstantVector(V))
1493  return T;
1494 
1495  return V->getType();
1496 }
1497 
1499  if (Instruction *I = commonCastTransforms(FPT))
1500  return I;
1501 
1502  // If we have fptrunc(OpI (fpextend x), (fpextend y)), we would like to
1503  // simplify this expression to avoid one or more of the trunc/extend
1504  // operations if we can do so without changing the numerical results.
1505  //
1506  // The exact manner in which the widths of the operands interact to limit
1507  // what we can and cannot do safely varies from operation to operation, and
1508  // is explained below in the various case statements.
1509  Type *Ty = FPT.getType();
1511  if (OpI && OpI->hasOneUse()) {
1512  Type *LHSMinType = getMinimumFPType(OpI->getOperand(0));
1513  Type *RHSMinType = getMinimumFPType(OpI->getOperand(1));
1514  unsigned OpWidth = OpI->getType()->getFPMantissaWidth();
1515  unsigned LHSWidth = LHSMinType->getFPMantissaWidth();
1516  unsigned RHSWidth = RHSMinType->getFPMantissaWidth();
1517  unsigned SrcWidth = std::max(LHSWidth, RHSWidth);
1518  unsigned DstWidth = Ty->getFPMantissaWidth();
1519  switch (OpI->getOpcode()) {
1520  default: break;
1521  case Instruction::FAdd:
1522  case Instruction::FSub:
1523  // For addition and subtraction, the infinitely precise result can
1524  // essentially be arbitrarily wide; proving that double rounding
1525  // will not occur because the result of OpI is exact (as we will for
1526  // FMul, for example) is hopeless. However, we *can* nonetheless
1527  // frequently know that double rounding cannot occur (or that it is
1528  // innocuous) by taking advantage of the specific structure of
1529  // infinitely-precise results that admit double rounding.
1530  //
1531  // Specifically, if OpWidth >= 2*DstWdith+1 and DstWidth is sufficient
1532  // to represent both sources, we can guarantee that the double
1533  // rounding is innocuous (See p50 of Figueroa's 2000 PhD thesis,
1534  // "A Rigorous Framework for Fully Supporting the IEEE Standard ..."
1535  // for proof of this fact).
1536  //
1537  // Note: Figueroa does not consider the case where DstFormat !=
1538  // SrcFormat. It's possible (likely even!) that this analysis
1539  // could be tightened for those cases, but they are rare (the main
1540  // case of interest here is (float)((double)float + float)).
1541  if (OpWidth >= 2*DstWidth+1 && DstWidth >= SrcWidth) {
1542  Value *LHS = Builder.CreateFPTrunc(OpI->getOperand(0), Ty);
1543  Value *RHS = Builder.CreateFPTrunc(OpI->getOperand(1), Ty);
1544  Instruction *RI = BinaryOperator::Create(OpI->getOpcode(), LHS, RHS);
1545  RI->copyFastMathFlags(OpI);
1546  return RI;
1547  }
1548  break;
1549  case Instruction::FMul:
1550  // For multiplication, the infinitely precise result has at most
1551  // LHSWidth + RHSWidth significant bits; if OpWidth is sufficient
1552  // that such a value can be exactly represented, then no double
1553  // rounding can possibly occur; we can safely perform the operation
1554  // in the destination format if it can represent both sources.
1555  if (OpWidth >= LHSWidth + RHSWidth && DstWidth >= SrcWidth) {
1556  Value *LHS = Builder.CreateFPTrunc(OpI->getOperand(0), Ty);
1557  Value *RHS = Builder.CreateFPTrunc(OpI->getOperand(1), Ty);
1558  return BinaryOperator::CreateFMulFMF(LHS, RHS, OpI);
1559  }
1560  break;
1561  case Instruction::FDiv:
1562  // For division, we use again use the bound from Figueroa's
1563  // dissertation. I am entirely certain that this bound can be
1564  // tightened in the unbalanced operand case by an analysis based on
1565  // the diophantine rational approximation bound, but the well-known
1566  // condition used here is a good conservative first pass.
1567  // TODO: Tighten bound via rigorous analysis of the unbalanced case.
1568  if (OpWidth >= 2*DstWidth && DstWidth >= SrcWidth) {
1569  Value *LHS = Builder.CreateFPTrunc(OpI->getOperand(0), Ty);
1570  Value *RHS = Builder.CreateFPTrunc(OpI->getOperand(1), Ty);
1571  return BinaryOperator::CreateFDivFMF(LHS, RHS, OpI);
1572  }
1573  break;
1574  case Instruction::FRem: {
1575  // Remainder is straightforward. Remainder is always exact, so the
1576  // type of OpI doesn't enter into things at all. We simply evaluate
1577  // in whichever source type is larger, then convert to the
1578  // destination type.
1579  if (SrcWidth == OpWidth)
1580  break;
1581  Value *LHS, *RHS;
1582  if (LHSWidth == SrcWidth) {
1583  LHS = Builder.CreateFPTrunc(OpI->getOperand(0), LHSMinType);
1584  RHS = Builder.CreateFPTrunc(OpI->getOperand(1), LHSMinType);
1585  } else {
1586  LHS = Builder.CreateFPTrunc(OpI->getOperand(0), RHSMinType);
1587  RHS = Builder.CreateFPTrunc(OpI->getOperand(1), RHSMinType);
1588  }
1589 
1590  Value *ExactResult = Builder.CreateFRemFMF(LHS, RHS, OpI);
1591  return CastInst::CreateFPCast(ExactResult, Ty);
1592  }
1593  }
1594 
1595  // (fptrunc (fneg x)) -> (fneg (fptrunc x))
1596  if (BinaryOperator::isFNeg(OpI)) {
1597  Value *InnerTrunc = Builder.CreateFPTrunc(OpI->getOperand(1), Ty);
1598  return BinaryOperator::CreateFNegFMF(InnerTrunc, OpI);
1599  }
1600  }
1601 
1602  if (auto *II = dyn_cast<IntrinsicInst>(FPT.getOperand(0))) {
1603  switch (II->getIntrinsicID()) {
1604  default: break;
1605  case Intrinsic::ceil:
1606  case Intrinsic::fabs:
1607  case Intrinsic::floor:
1608  case Intrinsic::nearbyint:
1609  case Intrinsic::rint:
1610  case Intrinsic::round:
1611  case Intrinsic::trunc: {
1612  Value *Src = II->getArgOperand(0);
1613  if (!Src->hasOneUse())
1614  break;
1615 
1616  // Except for fabs, this transformation requires the input of the unary FP
1617  // operation to be itself an fpext from the type to which we're
1618  // truncating.
1619  if (II->getIntrinsicID() != Intrinsic::fabs) {
1620  FPExtInst *FPExtSrc = dyn_cast<FPExtInst>(Src);
1621  if (!FPExtSrc || FPExtSrc->getSrcTy() != Ty)
1622  break;
1623  }
1624 
1625  // Do unary FP operation on smaller type.
1626  // (fptrunc (fabs x)) -> (fabs (fptrunc x))
1627  Value *InnerTrunc = Builder.CreateFPTrunc(Src, Ty);
1628  Function *Overload = Intrinsic::getDeclaration(FPT.getModule(),
1629  II->getIntrinsicID(), Ty);
1631  II->getOperandBundlesAsDefs(OpBundles);
1632  CallInst *NewCI = CallInst::Create(Overload, { InnerTrunc }, OpBundles,
1633  II->getName());
1634  NewCI->copyFastMathFlags(II);
1635  return NewCI;
1636  }
1637  }
1638  }
1639 
1640  if (Instruction *I = shrinkInsertElt(FPT, Builder))
1641  return I;
1642 
1643  return nullptr;
1644 }
1645 
1647  return commonCastTransforms(CI);
1648 }
1649 
1650 // fpto{s/u}i({u/s}itofp(X)) --> X or zext(X) or sext(X) or trunc(X)
1651 // This is safe if the intermediate type has enough bits in its mantissa to
1652 // accurately represent all values of X. For example, this won't work with
1653 // i64 -> float -> i64.
1655  if (!isa<UIToFPInst>(FI.getOperand(0)) && !isa<SIToFPInst>(FI.getOperand(0)))
1656  return nullptr;
1657  Instruction *OpI = cast<Instruction>(FI.getOperand(0));
1658 
1659  Value *SrcI = OpI->getOperand(0);
1660  Type *FITy = FI.getType();
1661  Type *OpITy = OpI->getType();
1662  Type *SrcTy = SrcI->getType();
1663  bool IsInputSigned = isa<SIToFPInst>(OpI);
1664  bool IsOutputSigned = isa<FPToSIInst>(FI);
1665 
1666  // We can safely assume the conversion won't overflow the output range,
1667  // because (for example) (uint8_t)18293.f is undefined behavior.
1668 
1669  // Since we can assume the conversion won't overflow, our decision as to
1670  // whether the input will fit in the float should depend on the minimum
1671  // of the input range and output range.
1672 
1673  // This means this is also safe for a signed input and unsigned output, since
1674  // a negative input would lead to undefined behavior.
1675  int InputSize = (int)SrcTy->getScalarSizeInBits() - IsInputSigned;
1676  int OutputSize = (int)FITy->getScalarSizeInBits() - IsOutputSigned;
1677  int ActualSize = std::min(InputSize, OutputSize);
1678 
1679  if (ActualSize <= OpITy->getFPMantissaWidth()) {
1680  if (FITy->getScalarSizeInBits() > SrcTy->getScalarSizeInBits()) {
1681  if (IsInputSigned && IsOutputSigned)
1682  return new SExtInst(SrcI, FITy);
1683  return new ZExtInst(SrcI, FITy);
1684  }
1685  if (FITy->getScalarSizeInBits() < SrcTy->getScalarSizeInBits())
1686  return new TruncInst(SrcI, FITy);
1687  if (SrcTy == FITy)
1688  return replaceInstUsesWith(FI, SrcI);
1689  return new BitCastInst(SrcI, FITy);
1690  }
1691  return nullptr;
1692 }
1693 
1695  Instruction *OpI = dyn_cast<Instruction>(FI.getOperand(0));
1696  if (!OpI)
1697  return commonCastTransforms(FI);
1698 
1699  if (Instruction *I = FoldItoFPtoI(FI))
1700  return I;
1701 
1702  return commonCastTransforms(FI);
1703 }
1704 
1706  Instruction *OpI = dyn_cast<Instruction>(FI.getOperand(0));
1707  if (!OpI)
1708  return commonCastTransforms(FI);
1709 
1710  if (Instruction *I = FoldItoFPtoI(FI))
1711  return I;
1712 
1713  return commonCastTransforms(FI);
1714 }
1715 
1717  return commonCastTransforms(CI);
1718 }
1719 
1721  return commonCastTransforms(CI);
1722 }
1723 
1725  // If the source integer type is not the intptr_t type for this target, do a
1726  // trunc or zext to the intptr_t type, then inttoptr of it. This allows the
1727  // cast to be exposed to other transforms.
1728  unsigned AS = CI.getAddressSpace();
1729  if (CI.getOperand(0)->getType()->getScalarSizeInBits() !=
1730  DL.getPointerSizeInBits(AS)) {
1731  Type *Ty = DL.getIntPtrType(CI.getContext(), AS);
1732  if (CI.getType()->isVectorTy()) // Handle vectors of pointers.
1733  Ty = VectorType::get(Ty, CI.getType()->getVectorNumElements());
1734 
1735  Value *P = Builder.CreateZExtOrTrunc(CI.getOperand(0), Ty);
1736  return new IntToPtrInst(P, CI.getType());
1737  }
1738 
1739  if (Instruction *I = commonCastTransforms(CI))
1740  return I;
1741 
1742  return nullptr;
1743 }
1744 
1745 /// Implement the transforms for cast of pointer (bitcast/ptrtoint)
1747  Value *Src = CI.getOperand(0);
1748 
1749  if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Src)) {
1750  // If casting the result of a getelementptr instruction with no offset, turn
1751  // this into a cast of the original pointer!
1752  if (GEP->hasAllZeroIndices() &&
1753  // If CI is an addrspacecast and GEP changes the poiner type, merging
1754  // GEP into CI would undo canonicalizing addrspacecast with different
1755  // pointer types, causing infinite loops.
1756  (!isa<AddrSpaceCastInst>(CI) ||
1757  GEP->getType() == GEP->getPointerOperandType())) {
1758  // Changing the cast operand is usually not a good idea but it is safe
1759  // here because the pointer operand is being replaced with another
1760  // pointer operand so the opcode doesn't need to change.
1761  Worklist.Add(GEP);
1762  CI.setOperand(0, GEP->getOperand(0));
1763  return &CI;
1764  }
1765  }
1766 
1767  return commonCastTransforms(CI);
1768 }
1769 
1771  // If the destination integer type is not the intptr_t type for this target,
1772  // do a ptrtoint to intptr_t then do a trunc or zext. This allows the cast
1773  // to be exposed to other transforms.
1774 
1775  Type *Ty = CI.getType();
1776  unsigned AS = CI.getPointerAddressSpace();
1777 
1778  if (Ty->getScalarSizeInBits() == DL.getIndexSizeInBits(AS))
1779  return commonPointerCastTransforms(CI);
1780 
1781  Type *PtrTy = DL.getIntPtrType(CI.getContext(), AS);
1782  if (Ty->isVectorTy()) // Handle vectors of pointers.
1783  PtrTy = VectorType::get(PtrTy, Ty->getVectorNumElements());
1784 
1785  Value *P = Builder.CreatePtrToInt(CI.getOperand(0), PtrTy);
1786  return CastInst::CreateIntegerCast(P, Ty, /*isSigned=*/false);
1787 }
1788 
1789 /// This input value (which is known to have vector type) is being zero extended
1790 /// or truncated to the specified vector type.
1791 /// Try to replace it with a shuffle (and vector/vector bitcast) if possible.
1792 ///
1793 /// The source and destination vector types may have different element types.
1795  InstCombiner &IC) {
1796  // We can only do this optimization if the output is a multiple of the input
1797  // element size, or the input is a multiple of the output element size.
1798  // Convert the input type to have the same element type as the output.
1799  VectorType *SrcTy = cast<VectorType>(InVal->getType());
1800 
1801  if (SrcTy->getElementType() != DestTy->getElementType()) {
1802  // The input types don't need to be identical, but for now they must be the
1803  // same size. There is no specific reason we couldn't handle things like
1804  // <4 x i16> -> <4 x i32> by bitcasting to <2 x i32> but haven't gotten
1805  // there yet.
1806  if (SrcTy->getElementType()->getPrimitiveSizeInBits() !=
1808  return nullptr;
1809 
1810  SrcTy = VectorType::get(DestTy->getElementType(), SrcTy->getNumElements());
1811  InVal = IC.Builder.CreateBitCast(InVal, SrcTy);
1812  }
1813 
1814  // Now that the element types match, get the shuffle mask and RHS of the
1815  // shuffle to use, which depends on whether we're increasing or decreasing the
1816  // size of the input.
1817  SmallVector<uint32_t, 16> ShuffleMask;
1818  Value *V2;
1819 
1820  if (SrcTy->getNumElements() > DestTy->getNumElements()) {
1821  // If we're shrinking the number of elements, just shuffle in the low
1822  // elements from the input and use undef as the second shuffle input.
1823  V2 = UndefValue::get(SrcTy);
1824  for (unsigned i = 0, e = DestTy->getNumElements(); i != e; ++i)
1825  ShuffleMask.push_back(i);
1826 
1827  } else {
1828  // If we're increasing the number of elements, shuffle in all of the
1829  // elements from InVal and fill the rest of the result elements with zeros
1830  // from a constant zero.
1831  V2 = Constant::getNullValue(SrcTy);
1832  unsigned SrcElts = SrcTy->getNumElements();
1833  for (unsigned i = 0, e = SrcElts; i != e; ++i)
1834  ShuffleMask.push_back(i);
1835 
1836  // The excess elements reference the first element of the zero input.
1837  for (unsigned i = 0, e = DestTy->getNumElements()-SrcElts; i != e; ++i)
1838  ShuffleMask.push_back(SrcElts);
1839  }
1840 
1841  return new ShuffleVectorInst(InVal, V2,
1843  ShuffleMask));
1844 }
1845 
1846 static bool isMultipleOfTypeSize(unsigned Value, Type *Ty) {
1847  return Value % Ty->getPrimitiveSizeInBits() == 0;
1848 }
1849 
1850 static unsigned getTypeSizeIndex(unsigned Value, Type *Ty) {
1851  return Value / Ty->getPrimitiveSizeInBits();
1852 }
1853 
1854 /// V is a value which is inserted into a vector of VecEltTy.
1855 /// Look through the value to see if we can decompose it into
1856 /// insertions into the vector. See the example in the comment for
1857 /// OptimizeIntegerToVectorInsertions for the pattern this handles.
1858 /// The type of V is always a non-zero multiple of VecEltTy's size.
1859 /// Shift is the number of bits between the lsb of V and the lsb of
1860 /// the vector.
1861 ///
1862 /// This returns false if the pattern can't be matched or true if it can,
1863 /// filling in Elements with the elements found here.
1864 static bool collectInsertionElements(Value *V, unsigned Shift,
1865  SmallVectorImpl<Value *> &Elements,
1866  Type *VecEltTy, bool isBigEndian) {
1867  assert(isMultipleOfTypeSize(Shift, VecEltTy) &&
1868  "Shift should be a multiple of the element type size");
1869 
1870  // Undef values never contribute useful bits to the result.
1871  if (isa<UndefValue>(V)) return true;
1872 
1873  // If we got down to a value of the right type, we win, try inserting into the
1874  // right element.
1875  if (V->getType() == VecEltTy) {
1876  // Inserting null doesn't actually insert any elements.
1877  if (Constant *C = dyn_cast<Constant>(V))
1878  if (C->isNullValue())
1879  return true;
1880 
1881  unsigned ElementIndex = getTypeSizeIndex(Shift, VecEltTy);
1882  if (isBigEndian)
1883  ElementIndex = Elements.size() - ElementIndex - 1;
1884 
1885  // Fail if multiple elements are inserted into this slot.
1886  if (Elements[ElementIndex])
1887  return false;
1888 
1889  Elements[ElementIndex] = V;
1890  return true;
1891  }
1892 
1893  if (Constant *C = dyn_cast<Constant>(V)) {
1894  // Figure out the # elements this provides, and bitcast it or slice it up
1895  // as required.
1896  unsigned NumElts = getTypeSizeIndex(C->getType()->getPrimitiveSizeInBits(),
1897  VecEltTy);
1898  // If the constant is the size of a vector element, we just need to bitcast
1899  // it to the right type so it gets properly inserted.
1900  if (NumElts == 1)
1902  Shift, Elements, VecEltTy, isBigEndian);
1903 
1904  // Okay, this is a constant that covers multiple elements. Slice it up into
1905  // pieces and insert each element-sized piece into the vector.
1906  if (!isa<IntegerType>(C->getType()))
1909  unsigned ElementSize = VecEltTy->getPrimitiveSizeInBits();
1910  Type *ElementIntTy = IntegerType::get(C->getContext(), ElementSize);
1911 
1912  for (unsigned i = 0; i != NumElts; ++i) {
1913  unsigned ShiftI = Shift+i*ElementSize;
1915  ShiftI));
1916  Piece = ConstantExpr::getTrunc(Piece, ElementIntTy);
1917  if (!collectInsertionElements(Piece, ShiftI, Elements, VecEltTy,
1918  isBigEndian))
1919  return false;
1920  }
1921  return true;
1922  }
1923 
1924  if (!V->hasOneUse()) return false;
1925 
1927  if (!I) return false;
1928  switch (I->getOpcode()) {
1929  default: return false; // Unhandled case.
1930  case Instruction::BitCast:
1931  return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
1932  isBigEndian);
1933  case Instruction::ZExt:
1934  if (!isMultipleOfTypeSize(
1936  VecEltTy))
1937  return false;
1938  return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
1939  isBigEndian);
1940  case Instruction::Or:
1941  return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
1942  isBigEndian) &&
1943  collectInsertionElements(I->getOperand(1), Shift, Elements, VecEltTy,
1944  isBigEndian);
1945  case Instruction::Shl: {
1946  // Must be shifting by a constant that is a multiple of the element size.
1948  if (!CI) return false;
1949  Shift += CI->getZExtValue();
1950  if (!isMultipleOfTypeSize(Shift, VecEltTy)) return false;
1951  return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
1952  isBigEndian);
1953  }
1954 
1955  }
1956 }
1957 
1958 
1959 /// If the input is an 'or' instruction, we may be doing shifts and ors to
1960 /// assemble the elements of the vector manually.
1961 /// Try to rip the code out and replace it with insertelements. This is to
1962 /// optimize code like this:
1963 ///
1964 /// %tmp37 = bitcast float %inc to i32
1965 /// %tmp38 = zext i32 %tmp37 to i64
1966 /// %tmp31 = bitcast float %inc5 to i32
1967 /// %tmp32 = zext i32 %tmp31 to i64
1968 /// %tmp33 = shl i64 %tmp32, 32
1969 /// %ins35 = or i64 %tmp33, %tmp38
1970 /// %tmp43 = bitcast i64 %ins35 to <2 x float>
1971 ///
1972 /// Into two insertelements that do "buildvector{%inc, %inc5}".
1974  InstCombiner &IC) {
1975  VectorType *DestVecTy = cast<VectorType>(CI.getType());
1976  Value *IntInput = CI.getOperand(0);
1977 
1978  SmallVector<Value*, 8> Elements(DestVecTy->getNumElements());
1979  if (!collectInsertionElements(IntInput, 0, Elements,
1980  DestVecTy->getElementType(),
1981  IC.getDataLayout().isBigEndian()))
1982  return nullptr;
1983 
1984  // If we succeeded, we know that all of the element are specified by Elements
1985  // or are zero if Elements has a null entry. Recast this as a set of
1986  // insertions.
1987  Value *Result = Constant::getNullValue(CI.getType());
1988  for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
1989  if (!Elements[i]) continue; // Unset element.
1990 
1991  Result = IC.Builder.CreateInsertElement(Result, Elements[i],
1992  IC.Builder.getInt32(i));
1993  }
1994 
1995  return Result;
1996 }
1997 
1998 /// Canonicalize scalar bitcasts of extracted elements into a bitcast of the
1999 /// vector followed by extract element. The backend tends to handle bitcasts of
2000 /// vectors better than bitcasts of scalars because vector registers are
2001 /// usually not type-specific like scalar integer or scalar floating-point.
2003  InstCombiner &IC) {
2004  // TODO: Create and use a pattern matcher for ExtractElementInst.
2005  auto *ExtElt = dyn_cast<ExtractElementInst>(BitCast.getOperand(0));
2006  if (!ExtElt || !ExtElt->hasOneUse())
2007  return nullptr;
2008 
2009  // The bitcast must be to a vectorizable type, otherwise we can't make a new
2010  // type to extract from.
2011  Type *DestType = BitCast.getType();
2012  if (!VectorType::isValidElementType(DestType))
2013  return nullptr;
2014 
2015  unsigned NumElts = ExtElt->getVectorOperandType()->getNumElements();
2016  auto *NewVecType = VectorType::get(DestType, NumElts);
2017  auto *NewBC = IC.Builder.CreateBitCast(ExtElt->getVectorOperand(),
2018  NewVecType, "bc");
2019  return ExtractElementInst::Create(NewBC, ExtElt->getIndexOperand());
2020 }
2021 
2022 /// Change the type of a bitwise logic operation if we can eliminate a bitcast.
2024  InstCombiner::BuilderTy &Builder) {
2025  Type *DestTy = BitCast.getType();
2026  BinaryOperator *BO;
2027  if (!DestTy->isIntOrIntVectorTy() ||
2028  !match(BitCast.getOperand(0), m_OneUse(m_BinOp(BO))) ||
2029  !BO->isBitwiseLogicOp())
2030  return nullptr;
2031 
2032  // FIXME: This transform is restricted to vector types to avoid backend
2033  // problems caused by creating potentially illegal operations. If a fix-up is
2034  // added to handle that situation, we can remove this check.
2035  if (!DestTy->isVectorTy() || !BO->getType()->isVectorTy())
2036  return nullptr;
2037 
2038  Value *X;
2039  if (match(BO->getOperand(0), m_OneUse(m_BitCast(m_Value(X)))) &&
2040  X->getType() == DestTy && !isa<Constant>(X)) {
2041  // bitcast(logic(bitcast(X), Y)) --> logic'(X, bitcast(Y))
2042  Value *CastedOp1 = Builder.CreateBitCast(BO->getOperand(1), DestTy);
2043  return BinaryOperator::Create(BO->getOpcode(), X, CastedOp1);
2044  }
2045 
2046  if (match(BO->getOperand(1), m_OneUse(m_BitCast(m_Value(X)))) &&
2047  X->getType() == DestTy && !isa<Constant>(X)) {
2048  // bitcast(logic(Y, bitcast(X))) --> logic'(bitcast(Y), X)
2049  Value *CastedOp0 = Builder.CreateBitCast(BO->getOperand(0), DestTy);
2050  return BinaryOperator::Create(BO->getOpcode(), CastedOp0, X);
2051  }
2052 
2053  // Canonicalize vector bitcasts to come before vector bitwise logic with a
2054  // constant. This eases recognition of special constants for later ops.
2055  // Example:
2056  // icmp u/s (a ^ signmask), (b ^ signmask) --> icmp s/u a, b
2057  Constant *C;
2058  if (match(BO->getOperand(1), m_Constant(C))) {
2059  // bitcast (logic X, C) --> logic (bitcast X, C')
2060  Value *CastedOp0 = Builder.CreateBitCast(BO->getOperand(0), DestTy);
2061  Value *CastedC = ConstantExpr::getBitCast(C, DestTy);
2062  return BinaryOperator::Create(BO->getOpcode(), CastedOp0, CastedC);
2063  }
2064 
2065  return nullptr;
2066 }
2067 
2068 /// Change the type of a select if we can eliminate a bitcast.
2070  InstCombiner::BuilderTy &Builder) {
2071  Value *Cond, *TVal, *FVal;
2072  if (!match(BitCast.getOperand(0),
2073  m_OneUse(m_Select(m_Value(Cond), m_Value(TVal), m_Value(FVal)))))
2074  return nullptr;
2075 
2076  // A vector select must maintain the same number of elements in its operands.
2077  Type *CondTy = Cond->getType();
2078  Type *DestTy = BitCast.getType();
2079  if (CondTy->isVectorTy()) {
2080  if (!DestTy->isVectorTy())
2081  return nullptr;
2082  if (DestTy->getVectorNumElements() != CondTy->getVectorNumElements())
2083  return nullptr;
2084  }
2085 
2086  // FIXME: This transform is restricted from changing the select between
2087  // scalars and vectors to avoid backend problems caused by creating
2088  // potentially illegal operations. If a fix-up is added to handle that
2089  // situation, we can remove this check.
2090  if (DestTy->isVectorTy() != TVal->getType()->isVectorTy())
2091  return nullptr;
2092 
2093  auto *Sel = cast<Instruction>(BitCast.getOperand(0));
2094  Value *X;
2095  if (match(TVal, m_OneUse(m_BitCast(m_Value(X)))) && X->getType() == DestTy &&
2096  !isa<Constant>(X)) {
2097  // bitcast(select(Cond, bitcast(X), Y)) --> select'(Cond, X, bitcast(Y))
2098  Value *CastedVal = Builder.CreateBitCast(FVal, DestTy);
2099  return SelectInst::Create(Cond, X, CastedVal, "", nullptr, Sel);
2100  }
2101 
2102  if (match(FVal, m_OneUse(m_BitCast(m_Value(X)))) && X->getType() == DestTy &&
2103  !isa<Constant>(X)) {
2104  // bitcast(select(Cond, Y, bitcast(X))) --> select'(Cond, bitcast(Y), X)
2105  Value *CastedVal = Builder.CreateBitCast(TVal, DestTy);
2106  return SelectInst::Create(Cond, CastedVal, X, "", nullptr, Sel);
2107  }
2108 
2109  return nullptr;
2110 }
2111 
2112 /// Check if all users of CI are StoreInsts.
2113 static bool hasStoreUsersOnly(CastInst &CI) {
2114  for (User *U : CI.users()) {
2115  if (!isa<StoreInst>(U))
2116  return false;
2117  }
2118  return true;
2119 }
2120 
2121 /// This function handles following case
2122 ///
2123 /// A -> B cast
2124 /// PHI
2125 /// B -> A cast
2126 ///
2127 /// All the related PHI nodes can be replaced by new PHI nodes with type A.
2128 /// The uses of \p CI can be changed to the new PHI node corresponding to \p PN.
2129 Instruction *InstCombiner::optimizeBitCastFromPhi(CastInst &CI, PHINode *PN) {
2130  // BitCast used by Store can be handled in InstCombineLoadStoreAlloca.cpp.
2131  if (hasStoreUsersOnly(CI))
2132  return nullptr;
2133 
2134  Value *Src = CI.getOperand(0);
2135  Type *SrcTy = Src->getType(); // Type B
2136  Type *DestTy = CI.getType(); // Type A
2137 
2138  SmallVector<PHINode *, 4> PhiWorklist;
2139  SmallSetVector<PHINode *, 4> OldPhiNodes;
2140 
2141  // Find all of the A->B casts and PHI nodes.
2142  // We need to inpect all related PHI nodes, but PHIs can be cyclic, so
2143  // OldPhiNodes is used to track all known PHI nodes, before adding a new
2144  // PHI to PhiWorklist, it is checked against and added to OldPhiNodes first.
2145  PhiWorklist.push_back(PN);
2146  OldPhiNodes.insert(PN);
2147  while (!PhiWorklist.empty()) {
2148  auto *OldPN = PhiWorklist.pop_back_val();
2149  for (Value *IncValue : OldPN->incoming_values()) {
2150  if (isa<Constant>(IncValue))
2151  continue;
2152 
2153  if (auto *LI = dyn_cast<LoadInst>(IncValue)) {
2154  // If there is a sequence of one or more load instructions, each loaded
2155  // value is used as address of later load instruction, bitcast is
2156  // necessary to change the value type, don't optimize it. For
2157  // simplicity we give up if the load address comes from another load.
2158  Value *Addr = LI->getOperand(0);
2159  if (Addr == &CI || isa<LoadInst>(Addr))
2160  return nullptr;
2161  if (LI->hasOneUse() && LI->isSimple())
2162  continue;
2163  // If a LoadInst has more than one use, changing the type of loaded
2164  // value may create another bitcast.
2165  return nullptr;
2166  }
2167 
2168  if (auto *PNode = dyn_cast<PHINode>(IncValue)) {
2169  if (OldPhiNodes.insert(PNode))
2170  PhiWorklist.push_back(PNode);
2171  continue;
2172  }
2173 
2174  auto *BCI = dyn_cast<BitCastInst>(IncValue);
2175  // We can't handle other instructions.
2176  if (!BCI)
2177  return nullptr;
2178 
2179  // Verify it's a A->B cast.
2180  Type *TyA = BCI->getOperand(0)->getType();
2181  Type *TyB = BCI->getType();
2182  if (TyA != DestTy || TyB != SrcTy)
2183  return nullptr;
2184  }
2185  }
2186 
2187  // For each old PHI node, create a corresponding new PHI node with a type A.
2189  for (auto *OldPN : OldPhiNodes) {
2190  Builder.SetInsertPoint(OldPN);
2191  PHINode *NewPN = Builder.CreatePHI(DestTy, OldPN->getNumOperands());
2192  NewPNodes[OldPN] = NewPN;
2193  }
2194 
2195  // Fill in the operands of new PHI nodes.
2196  for (auto *OldPN : OldPhiNodes) {
2197  PHINode *NewPN = NewPNodes[OldPN];
2198  for (unsigned j = 0, e = OldPN->getNumOperands(); j != e; ++j) {
2199  Value *V = OldPN->getOperand(j);
2200  Value *NewV = nullptr;
2201  if (auto *C = dyn_cast<Constant>(V)) {
2202  NewV = ConstantExpr::getBitCast(C, DestTy);
2203  } else if (auto *LI = dyn_cast<LoadInst>(V)) {
2204  Builder.SetInsertPoint(LI->getNextNode());
2205  NewV = Builder.CreateBitCast(LI, DestTy);
2206  Worklist.Add(LI);
2207  } else if (auto *BCI = dyn_cast<BitCastInst>(V)) {
2208  NewV = BCI->getOperand(0);
2209  } else if (auto *PrevPN = dyn_cast<PHINode>(V)) {
2210  NewV = NewPNodes[PrevPN];
2211  }
2212  assert(NewV);
2213  NewPN->addIncoming(NewV, OldPN->getIncomingBlock(j));
2214  }
2215  }
2216 
2217  // If there is a store with type B, change it to type A.
2218  for (User *U : PN->users()) {
2219  auto *SI = dyn_cast<StoreInst>(U);
2220  if (SI && SI->isSimple() && SI->getOperand(0) == PN) {
2221  Builder.SetInsertPoint(SI);
2222  auto *NewBC =
2223  cast<BitCastInst>(Builder.CreateBitCast(NewPNodes[PN], SrcTy));
2224  SI->setOperand(0, NewBC);
2225  Worklist.Add(SI);
2226  assert(hasStoreUsersOnly(*NewBC));
2227  }
2228  }
2229 
2230  return replaceInstUsesWith(CI, NewPNodes[PN]);
2231 }
2232 
2234  // If the operands are integer typed then apply the integer transforms,
2235  // otherwise just apply the common ones.
2236  Value *Src = CI.getOperand(0);
2237  Type *SrcTy = Src->getType();
2238  Type *DestTy = CI.getType();
2239 
2240  // Get rid of casts from one type to the same type. These are useless and can
2241  // be replaced by the operand.
2242  if (DestTy == Src->getType())
2243  return replaceInstUsesWith(CI, Src);
2244 
2245  if (PointerType *DstPTy = dyn_cast<PointerType>(DestTy)) {
2246  PointerType *SrcPTy = cast<PointerType>(SrcTy);
2247  Type *DstElTy = DstPTy->getElementType();
2248  Type *SrcElTy = SrcPTy->getElementType();
2249 
2250  // If we are casting a alloca to a pointer to a type of the same
2251  // size, rewrite the allocation instruction to allocate the "right" type.
2252  // There is no need to modify malloc calls because it is their bitcast that
2253  // needs to be cleaned up.
2254  if (AllocaInst *AI = dyn_cast<AllocaInst>(Src))
2255  if (Instruction *V = PromoteCastOfAllocation(CI, *AI))
2256  return V;
2257 
2258  // When the type pointed to is not sized the cast cannot be
2259  // turned into a gep.
2260  Type *PointeeType =
2261  cast<PointerType>(Src->getType()->getScalarType())->getElementType();
2262  if (!PointeeType->isSized())
2263  return nullptr;
2264 
2265  // If the source and destination are pointers, and this cast is equivalent
2266  // to a getelementptr X, 0, 0, 0... turn it into the appropriate gep.
2267  // This can enhance SROA and other transforms that want type-safe pointers.
2268  unsigned NumZeros = 0;
2269  while (SrcElTy != DstElTy &&
2270  isa<CompositeType>(SrcElTy) && !SrcElTy->isPointerTy() &&
2271  SrcElTy->getNumContainedTypes() /* not "{}" */) {
2272  SrcElTy = cast<CompositeType>(SrcElTy)->getTypeAtIndex(0U);
2273  ++NumZeros;
2274  }
2275 
2276  // If we found a path from the src to dest, create the getelementptr now.
2277  if (SrcElTy == DstElTy) {
2278  SmallVector<Value *, 8> Idxs(NumZeros + 1, Builder.getInt32(0));
2279  return GetElementPtrInst::CreateInBounds(Src, Idxs);
2280  }
2281  }
2282 
2283  if (VectorType *DestVTy = dyn_cast<VectorType>(DestTy)) {
2284  if (DestVTy->getNumElements() == 1 && !SrcTy->isVectorTy()) {
2285  Value *Elem = Builder.CreateBitCast(Src, DestVTy->getElementType());
2286  return InsertElementInst::Create(UndefValue::get(DestTy), Elem,
2288  // FIXME: Canonicalize bitcast(insertelement) -> insertelement(bitcast)
2289  }
2290 
2291  if (isa<IntegerType>(SrcTy)) {
2292  // If this is a cast from an integer to vector, check to see if the input
2293  // is a trunc or zext of a bitcast from vector. If so, we can replace all
2294  // the casts with a shuffle and (potentially) a bitcast.
2295  if (isa<TruncInst>(Src) || isa<ZExtInst>(Src)) {
2296  CastInst *SrcCast = cast<CastInst>(Src);
2297  if (BitCastInst *BCIn = dyn_cast<BitCastInst>(SrcCast->getOperand(0)))
2298  if (isa<VectorType>(BCIn->getOperand(0)->getType()))
2299  if (Instruction *I = optimizeVectorResize(BCIn->getOperand(0),
2300  cast<VectorType>(DestTy), *this))
2301  return I;
2302  }
2303 
2304  // If the input is an 'or' instruction, we may be doing shifts and ors to
2305  // assemble the elements of the vector manually. Try to rip the code out
2306  // and replace it with insertelements.
2307  if (Value *V = optimizeIntegerToVectorInsertions(CI, *this))
2308  return replaceInstUsesWith(CI, V);
2309  }
2310  }
2311 
2312  if (VectorType *SrcVTy = dyn_cast<VectorType>(SrcTy)) {
2313  if (SrcVTy->getNumElements() == 1) {
2314  // If our destination is not a vector, then make this a straight
2315  // scalar-scalar cast.
2316  if (!DestTy->isVectorTy()) {
2317  Value *Elem =
2318  Builder.CreateExtractElement(Src,
2320  return CastInst::Create(Instruction::BitCast, Elem, DestTy);
2321  }
2322 
2323  // Otherwise, see if our source is an insert. If so, then use the scalar
2324  // component directly.
2325  if (InsertElementInst *IEI =
2326  dyn_cast<InsertElementInst>(CI.getOperand(0)))
2327  return CastInst::Create(Instruction::BitCast, IEI->getOperand(1),
2328  DestTy);
2329  }
2330  }
2331 
2332  if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(Src)) {
2333  // Okay, we have (bitcast (shuffle ..)). Check to see if this is
2334  // a bitcast to a vector with the same # elts.
2335  if (SVI->hasOneUse() && DestTy->isVectorTy() &&
2336  DestTy->getVectorNumElements() == SVI->getType()->getNumElements() &&
2337  SVI->getType()->getNumElements() ==
2338  SVI->getOperand(0)->getType()->getVectorNumElements()) {
2339  BitCastInst *Tmp;
2340  // If either of the operands is a cast from CI.getType(), then
2341  // evaluating the shuffle in the casted destination's type will allow
2342  // us to eliminate at least one cast.
2343  if (((Tmp = dyn_cast<BitCastInst>(SVI->getOperand(0))) &&
2344  Tmp->getOperand(0)->getType() == DestTy) ||
2345  ((Tmp = dyn_cast<BitCastInst>(SVI->getOperand(1))) &&
2346  Tmp->getOperand(0)->getType() == DestTy)) {
2347  Value *LHS = Builder.CreateBitCast(SVI->getOperand(0), DestTy);
2348  Value *RHS = Builder.CreateBitCast(SVI->getOperand(1), DestTy);
2349  // Return a new shuffle vector. Use the same element ID's, as we
2350  // know the vector types match #elts.
2351  return new ShuffleVectorInst(LHS, RHS, SVI->getOperand(2));
2352  }
2353  }
2354  }
2355 
2356  // Handle the A->B->A cast, and there is an intervening PHI node.
2357  if (PHINode *PN = dyn_cast<PHINode>(Src))
2358  if (Instruction *I = optimizeBitCastFromPhi(CI, PN))
2359  return I;
2360 
2361  if (Instruction *I = canonicalizeBitCastExtElt(CI, *this))
2362  return I;
2363 
2364  if (Instruction *I = foldBitCastBitwiseLogic(CI, Builder))
2365  return I;
2366 
2367  if (Instruction *I = foldBitCastSelect(CI, Builder))
2368  return I;
2369 
2370  if (SrcTy->isPointerTy())
2371  return commonPointerCastTransforms(CI);
2372  return commonCastTransforms(CI);
2373 }
2374 
2376  // If the destination pointer element type is not the same as the source's
2377  // first do a bitcast to the destination type, and then the addrspacecast.
2378  // This allows the cast to be exposed to other transforms.
2379  Value *Src = CI.getOperand(0);
2380  PointerType *SrcTy = cast<PointerType>(Src->getType()->getScalarType());
2381  PointerType *DestTy = cast<PointerType>(CI.getType()->getScalarType());
2382 
2383  Type *DestElemTy = DestTy->getElementType();
2384  if (SrcTy->getElementType() != DestElemTy) {
2385  Type *MidTy = PointerType::get(DestElemTy, SrcTy->getAddressSpace());
2386  if (VectorType *VT = dyn_cast<VectorType>(CI.getType())) {
2387  // Handle vectors of pointers.
2388  MidTy = VectorType::get(MidTy, VT->getNumElements());
2389  }
2390 
2391  Value *NewBitCast = Builder.CreateBitCast(Src, MidTy);
2392  return new AddrSpaceCastInst(NewBitCast, CI.getType());
2393  }
2394 
2395  return commonPointerCastTransforms(CI);
2396 }
static BinaryOperator * CreateFMulFMF(Value *V1, Value *V2, BinaryOperator *FMFSource, const Twine &Name="")
Definition: InstrTypes.h:405
BinaryOp_match< LHS, RHS, Instruction::And > m_And(const LHS &L, const RHS &R)
Definition: PatternMatch.h:709
uint64_t CallInst * C
BinOpPred_match< LHS, RHS, is_right_shift_op > m_Shr(const LHS &L, const RHS &R)
Matches logical shift operations.
Definition: PatternMatch.h:893
void push_back(const T &Elt)
Definition: SmallVector.h:213
void copyFastMathFlags(FastMathFlags FMF)
Convenience function for transferring all fast-math flag values to this instruction, which must be an operator which supports these flags.
class_match< Value > m_Value()
Match an arbitrary value and ignore it.
Definition: PatternMatch.h:72
This class is the base class for the comparison instructions.
Definition: InstrTypes.h:875
static GCMetadataPrinterRegistry::Add< ErlangGCPrinter > X("erlang", "erlang-compatible garbage collector")
static Type * getDoubleTy(LLVMContext &C)
Definition: Type.cpp:165
Type * getSrcTy() const
Return the source type, as a convenience.
Definition: InstrTypes.h:850
void addIncoming(Value *V, BasicBlock *BB)
Add an incoming value to the end of the PHI list.
uint64_t getZExtValue() const
Get zero extended value.
Definition: APInt.h:1547
GCNRegPressure max(const GCNRegPressure &P1, const GCNRegPressure &P2)
BinaryOp_match< LHS, RHS, Instruction::Sub > m_Sub(const LHS &L, const RHS &R)
Definition: PatternMatch.h:642
DiagnosticInfoOptimizationBase::Argument NV
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
BinaryOps getOpcode() const
Definition: InstrTypes.h:555
Instruction * visitBitCast(BitCastInst &CI)
bool isSized(SmallPtrSetImpl< Type *> *Visited=nullptr) const
Return true if it makes sense to take the size of this type.
Definition: Type.h:262
LLVM_ATTRIBUTE_ALWAYS_INLINE size_type size() const
Definition: SmallVector.h:137
void setAlignment(unsigned Align)
This class represents zero extension of integer types.
Instruction * commonCastTransforms(CastInst &CI)
Implement the transforms common to all CastInst visitors.
This class represents a function call, abstracting a target machine&#39;s calling convention.
static Type * shrinkFPConstant(ConstantFP *CFP)
static APInt getLowBitsSet(unsigned numBits, unsigned loBitsSet)
Get a value with low bits set.
Definition: APInt.h:641
class_match< Constant > m_Constant()
Match an arbitrary Constant and ignore it.
Definition: PatternMatch.h:91
static PointerType * get(Type *ElementType, unsigned AddressSpace)
This constructs a pointer to an object of the specified type in a numbered address space...
Definition: Type.cpp:617
static uint64_t round(uint64_t Acc, uint64_t Input)
Definition: xxhash.cpp:57
const Value * getTrueValue() const
BinaryOp_match< LHS, RHS, Instruction::AShr > m_AShr(const LHS &L, const RHS &R)
Definition: PatternMatch.h:739
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:713
static bool isEquality(Predicate P)
Return true if this predicate is either EQ or NE.
APInt trunc(unsigned width) const
Truncate to new width.
Definition: APInt.cpp:817
F(f)
static CallInst * Create(Value *Func, ArrayRef< Value *> Args, ArrayRef< OperandBundleDef > Bundles=None, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
This class represents a sign extension of integer types.
Hexagon Common GEP
bool isVectorTy() const
True if this is an instance of VectorType.
Definition: Type.h:227
static bool isBitwiseLogicOp(unsigned Opcode)
Determine if the Opcode is and/or/xor.
Definition: Instruction.h:161
Instruction * visitUIToFP(CastInst &CI)
unsigned getBitWidth() const
Return the number of bits in the APInt.
Definition: APInt.h:1493
BinOpPred_match< LHS, RHS, is_logical_shift_op > m_LogicalShift(const LHS &L, const RHS &R)
Matches logical shift operations.
Definition: PatternMatch.h:901
static Constant * getNullValue(Type *Ty)
Constructor to create a &#39;0&#39; constant of arbitrary type.
Definition: Constants.cpp:258
Instruction * visitFPExt(CastInst &CI)
Instruction * FoldItoFPtoI(Instruction &FI)
unsigned countTrailingZeros() const
Count the number of trailing zero bits.
Definition: APInt.h:1616
bool match(Val *V, const Pattern &P)
Definition: PatternMatch.h:49
static InsertElementInst * Create(Value *Vec, Value *NewElt, Value *Idx, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
Instruction * visitFPToUI(FPToUIInst &FI)
This class represents a conversion between pointers from one address space to another.
static Constant * getIntegerCast(Constant *C, Type *Ty, bool isSigned)
Create a ZExt, Bitcast or Trunc for integer -> integer casts.
Definition: Constants.cpp:1580
BinaryOp_match< LHS, RHS, Instruction::Xor > m_Xor(const LHS &L, const RHS &R)
Definition: PatternMatch.h:721
This class represents the LLVM &#39;select&#39; instruction.
unsigned getAlignment() const
Return the alignment of the memory that is being allocated by the instruction.
Definition: Instructions.h:109
static bool hasStoreUsersOnly(CastInst &CI)
Check if all users of CI are StoreInsts.
static Type * getFloatTy(LLVMContext &C)
Definition: Type.cpp:164
This is the base class for all instructions that perform data casts.
Definition: InstrTypes.h:592
PointerType * getType() const
Overload to return most specific pointer type.
Definition: Instructions.h:97
&#39;undef&#39; values are things that do not have specified contents.
Definition: Constants.h:1260
static Constant * getLShr(Constant *C1, Constant *C2, bool isExact=false)
Definition: Constants.cpp:2255
static bool canEvaluateZExtd(Value *V, Type *Ty, unsigned &BitsToClear, InstCombiner &IC, Instruction *CxtI)
Determine if the specified value can be computed in the specified wider type and produce the same low...
CastClass_match< OpTy, Instruction::Trunc > m_Trunc(const OpTy &Op)
Matches Trunc.
bool isIntegerTy() const
True if this is an instance of IntegerType.
Definition: Type.h:197
The core instruction combiner logic.
static bool canEvaluateTruncated(Value *V, Type *Ty, InstCombiner &IC, Instruction *CxtI)
Return true if we can evaluate the specified expression tree as type Ty instead of its larger type...
static Instruction * canonicalizeBitCastExtElt(BitCastInst &BitCast, InstCombiner &IC)
Canonicalize scalar bitcasts of extracted elements into a bitcast of the vector followed by extract e...
Instruction * visitIntToPtr(IntToPtrInst &CI)
static Instruction * optimizeVectorResize(Value *InVal, VectorType *DestTy, InstCombiner &IC)
This input value (which is known to have vector type) is being zero extended or truncated to the spec...
Instruction * visitAddrSpaceCast(AddrSpaceCastInst &CI)
uint64_t getNumElements() const
Definition: DerivedTypes.h:359
static Type * getPPC_FP128Ty(LLVMContext &C)
Definition: Type.cpp:170
static unsigned getTypeSizeIndex(unsigned Value, Type *Ty)
This class represents a cast from a pointer to an integer.
unsigned getPointerAddressSpace() const
Returns the address space of the pointer operand.
Constant * ConstantFoldConstant(const Constant *C, const DataLayout &DL, const TargetLibraryInfo *TLI=nullptr)
ConstantFoldConstant - Attempt to fold the constant using the specified DataLayout.
static Constant * getZExt(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1632
Value * CreateBitCast(Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1629
static bool isMultipleOfTypeSize(unsigned Value, Type *Ty)
Instruction::CastOps getOpcode() const
Return the opcode of this CastInst.
Definition: InstrTypes.h:845
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:245
bool insert(const value_type &X)
Insert a new element into the SetVector.
Definition: SetVector.h:142
opStatus convert(const fltSemantics &ToSemantics, roundingMode RM, bool *losesInfo)
Definition: APFloat.cpp:4444
match_combine_or< LTy, RTy > m_CombineOr(const LTy &L, const RTy &R)
Combine two pattern matchers matching L || R.
Definition: PatternMatch.h:125
CastClass_match< OpTy, Instruction::ZExt > m_ZExt(const OpTy &Op)
Matches ZExt.
#define T
bool isUsedWithInAlloca() const
Return true if this alloca is used as an inalloca argument to a call.
Definition: Instructions.h:121
static bool isValidElementType(Type *ElemTy)
Return true if the specified type is valid as a element type.
Definition: Type.cpp:608
static bool collectInsertionElements(Value *V, unsigned Shift, SmallVectorImpl< Value *> &Elements, Type *VecEltTy, bool isBigEndian)
V is a value which is inserted into a vector of VecEltTy.
This class represents a no-op cast from one type to another.
class_match< ConstantInt > m_ConstantInt()
Match an arbitrary ConstantInt and ignore it.
Definition: PatternMatch.h:83
const APInt & getValue() const
Return the constant as an APInt value reference.
Definition: Constants.h:138
static APInt getBitsSetFrom(unsigned numBits, unsigned loBit)
Get a value with upper bits starting at loBit set.
Definition: APInt.h:617
unsigned getOpcode() const
Returns a member of one of the enums like Instruction::Add.
Definition: Instruction.h:126
An instruction for storing to memory.
Definition: Instructions.h:306
bool isIntOrIntVectorTy() const
Return true if this is an integer type or a vector of integer types.
Definition: Type.h:203
int getFPMantissaWidth() const
Return the width of the mantissa of this type.
Definition: Type.cpp:134
This class represents a cast from floating point to signed integer.
SelectClass_match< Cond, LHS, RHS > m_Select(const Cond &C, const LHS &L, const RHS &R)
static Value * optimizeIntegerToVectorInsertions(BitCastInst &CI, InstCombiner &IC)
If the input is an &#39;or&#39; instruction, we may be doing shifts and ors to assemble the elements of the v...
static const fltSemantics & IEEEdouble() LLVM_READNONE
Definition: APFloat.cpp:123
static Type * getMinimumFPType(Value *V)
Find the minimum FP type we can safely truncate to.
void takeName(Value *V)
Transfer the name from V to this value.
Definition: Value.cpp:301
static Instruction * foldBitCastSelect(BitCastInst &BitCast, InstCombiner::BuilderTy &Builder)
Change the type of a select if we can eliminate a bitcast.
Function * getDeclaration(Module *M, ID id, ArrayRef< Type *> Tys=None)
Create or insert an LLVM Function declaration for an intrinsic, and return it.
Definition: Function.cpp:1001
This class represents a truncation of integer types.
Value * getOperand(unsigned i) const
Definition: User.h:170
Class to represent pointers.
Definition: DerivedTypes.h:467
Type * getScalarType() const
If this is a vector type, return the element type, otherwise return &#39;this&#39;.
Definition: Type.h:301
const DataLayout & getDataLayout() const
static APInt getHighBitsSet(unsigned numBits, unsigned hiBitsSet)
Get a value with high bits set.
Definition: APInt.h:629
static Constant * getBitCast(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1740
an instruction for type-safe pointer arithmetic to access elements of arrays and structs ...
Definition: Instructions.h:837
OneUse_match< T > m_OneUse(const T &SubPattern)
Definition: PatternMatch.h:63
#define P(N)
BinaryOp_match< LHS, RHS, Instruction::LShr > m_LShr(const LHS &L, const RHS &R)
Definition: PatternMatch.h:733
static Instruction * foldBitCastBitwiseLogic(BitCastInst &BitCast, InstCombiner::BuilderTy &Builder)
Change the type of a bitwise logic operation if we can eliminate a bitcast.
This instruction inserts a single (scalar) element into a VectorType value.
bool isAllOnesValue() const
Determine if all bits are set.
Definition: APInt.h:389
static bool canNotEvaluateInType(Value *V, Type *Ty)
Filter out values that we can not evaluate in the destination type for free.
uint64_t getZExtValue() const
Return the constant as a 64-bit unsigned integer value after it has been zero extended as appropriate...
Definition: Constants.h:149
apint_match m_APInt(const APInt *&Res)
Match a ConstantInt or splatted ConstantVector, binding the specified pointer to the contained APInt...
Definition: PatternMatch.h:177
unsigned countPopulation() const
Count the number of bits set.
Definition: APInt.h:1642
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:715
bool ult(const APInt &RHS) const
Unsigned less than comparison.
Definition: APInt.h:1169
CastClass_match< OpTy, Instruction::BitCast > m_BitCast(const OpTy &Op)
Matches BitCast.
This is an important base class in LLVM.
Definition: Constant.h:42
unsigned getNumContainedTypes() const
Return the number of types in the derived type.
Definition: Type.h:336
void setUsedWithInAlloca(bool V)
Specify whether this alloca is used to represent the arguments to a call.
Definition: Instructions.h:126
bool isPointerTy() const
True if this is an instance of PointerType.
Definition: Type.h:221
bool MaskedValueIsZero(const Value *V, const APInt &Mask, const DataLayout &DL, unsigned Depth=0, AssumptionCache *AC=nullptr, const Instruction *CxtI=nullptr, const DominatorTree *DT=nullptr)
Return true if &#39;V & Mask&#39; is known to be zero.
ConstantFP - Floating Point Values [float, double].
Definition: Constants.h:264
specificval_ty m_Specific(const Value *V)
Match if we have a specific specified value.
Definition: PatternMatch.h:490
BinaryOp_match< LHS, RHS, Instruction::Shl > m_Shl(const LHS &L, const RHS &R)
Definition: PatternMatch.h:727
static Value * decomposeSimpleLinearExpr(Value *Val, unsigned &Scale, uint64_t &Offset)
Analyze &#39;Val&#39;, seeing if it is a simple linear expression.
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:885
Utility class for integer operators which may exhibit overflow - Add, Sub, Mul, and Shl...
Definition: Operator.h:67
match_combine_or< CastClass_match< OpTy, Instruction::ZExt >, CastClass_match< OpTy, Instruction::SExt > > m_ZExtOrSExt(const OpTy &Op)
unsigned getAddressSpace() const
Return the address space of the Pointer type.
Definition: DerivedTypes.h:495
self_iterator getIterator()
Definition: ilist_node.h:82
class_match< BinaryOperator > m_BinOp()
Match an arbitrary binary operation and ignore it.
Definition: PatternMatch.h:75
unsigned getAddressSpace() const
Returns the address space of this instruction&#39;s pointer type.
Class to represent integer types.
Definition: DerivedTypes.h:40
static bool fitsInFPType(ConstantFP *CFP, const fltSemantics &Sem)
Return a Constant* for the specified floating-point constant if it fits in the specified FP type with...
This class represents a cast from an integer to a pointer.
static Constant * getAllOnesValue(Type *Ty)
Definition: Constants.cpp:312
Instruction * visitFPToSI(FPToSIInst &FI)
static UndefValue * get(Type *T)
Static factory methods - Return an &#39;undef&#39; object of the specified type.
Definition: Constants.cpp:1382
const AMDGPUAS & AS
const Value * getArraySize() const
Get the number of elements allocated.
Definition: Instructions.h:93
Value * getIncomingValue(unsigned i) const
Return incoming value number x.
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
Value * CreateTrunc(Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1552
Type * getAllocatedType() const
Return the type that is being allocated by the instruction.
Definition: Instructions.h:102
signed greater than
Definition: InstrTypes.h:912
const APFloat & getValueAPF() const
Definition: Constants.h:299
CastClass_match< OpTy, Instruction::SExt > m_SExt(const OpTy &Op)
Matches SExt.
static Type * getHalfTy(LLVMContext &C)
Definition: Type.cpp:163
bool isPtrOrPtrVectorTy() const
Return true if this is a pointer type or a vector of pointer types.
Definition: Type.h:224
static IntegerType * get(LLVMContext &C, unsigned NumBits)
This static method is the primary way of constructing an IntegerType.
Definition: Type.cpp:240
static const fltSemantics & IEEEsingle() LLVM_READNONE
Definition: APFloat.cpp:120
static CastInst * CreateIntegerCast(Value *S, Type *Ty, bool isSigned, const Twine &Name="", Instruction *InsertBefore=nullptr)
Create a ZExt, BitCast, or Trunc for int -> int casts.
A SetVector that performs no allocations if smaller than a certain size.
Definition: SetVector.h:298
This is the shared class of boolean and integer constants.
Definition: Constants.h:84
static const fltSemantics & IEEEhalf() LLVM_READNONE
Definition: APFloat.cpp:117
SelectPatternFlavor Flavor
unsigned ComputeNumSignBits(const Value *Op, const DataLayout &DL, unsigned Depth=0, AssumptionCache *AC=nullptr, const Instruction *CxtI=nullptr, const DominatorTree *DT=nullptr)
Return the number of times the sign bit of the register is replicated into the other bits...
static Instruction * shrinkInsertElt(CastInst &Trunc, InstCombiner::BuilderTy &Builder)
Try to narrow the width of an insert element.
unsigned getScalarSizeInBits() const LLVM_READONLY
If this is a vector type, return the getPrimitiveSizeInBits value for the element type...
Definition: Type.cpp:130
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:861
Instruction * user_back()
Specialize the methods defined in Value, as we know that an instruction can only be used by other ins...
Definition: Instruction.h:64
Value * CreateInsertElement(Value *Vec, Value *NewElt, Value *Idx, const Twine &Name="")
Definition: IRBuilder.h:1934
static Instruction * shrinkSplatShuffle(TruncInst &Trunc, InstCombiner::BuilderTy &Builder)
Try to narrow the width of a splat shuffle.
Instruction * visitSExt(SExtInst &CI)
signed less than
Definition: InstrTypes.h:914
This class represents a cast from floating point to unsigned integer.
LLVM_NODISCARD T pop_back_val()
Definition: SmallVector.h:382
Instruction * visitZExt(ZExtInst &CI)
ConstantInt * getInt32(uint32_t C)
Get a constant 32-bit value.
Definition: IRBuilder.h:307
static CastInst * CreateFPCast(Value *S, Type *Ty, const Twine &Name="", Instruction *InsertBefore=nullptr)
Create an FPExt, BitCast, or FPTrunc for fp -> fp casts.
static unsigned isEliminableCastPair(Instruction::CastOps firstOpcode, Instruction::CastOps secondOpcode, Type *SrcTy, Type *MidTy, Type *DstTy, Type *SrcIntPtrTy, Type *MidIntPtrTy, Type *DstIntPtrTy)
Determine how a pair of casts can be eliminated, if they can be at all.
static Constant * getTrunc(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1604
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:611
static PHINode * Create(Type *Ty, unsigned NumReservedValues, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
Constructors - NumReservedValues is a hint for the number of incoming edges that this phi node will h...
Type * getDestTy() const
Return the destination type, as a convenience.
Definition: InstrTypes.h:852
unsigned getNumIncomingValues() const
Return the number of incoming edges.
bool uge(const APInt &RHS) const
Unsigned greater or equal comparison.
Definition: APInt.h:1277
static BinaryOperator * CreateFDivFMF(Value *V1, Value *V2, BinaryOperator *FMFSource, const Twine &Name="")
Definition: InstrTypes.h:410
void setOperand(unsigned i, Value *Val)
Definition: User.h:175
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:133
unsigned getVectorNumElements() const
Definition: DerivedTypes.h:462
Class to represent vector types.
Definition: DerivedTypes.h:393
const Module * getModule() const
Return the module owning the function this instruction belongs to or nullptr it the function does not...
Definition: Instruction.cpp:55
Class for arbitrary precision integers.
Definition: APInt.h:69
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.
iterator_range< user_iterator > users()
Definition: Value.h:399
bool hasNoSignedWrap() const
Test whether this operation is known to never undergo signed overflow, aka the nsw property...
Definition: Operator.h:96
const Value * getFalseValue() const
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 ...
Predicate getPredicate() const
Return the predicate for this instruction.
Definition: InstrTypes.h:959
Instruction * visitTrunc(TruncInst &CI)
static Type * shrinkFPConstantVector(Value *V)
static IntegerType * getInt32Ty(LLVMContext &C)
Definition: Type.cpp:176
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:62
Instruction * visitSIToFP(CastInst &CI)
uint64_t getLimitedValue(uint64_t Limit=UINT64_MAX) const
If this value is smaller than the specified limit, return it, otherwise return the limit value...
Definition: APInt.h:475
static bool isFNeg(const Value *V, bool IgnoreZeroSign=false)
StringRef getName() const
Return a constant reference to the value&#39;s name.
Definition: Value.cpp:224
BasicBlock * getIncomingBlock(unsigned i) const
Return incoming basic block number i.
#define I(x, y, z)
Definition: MD5.cpp:58
static Instruction * foldVecTruncToExtElt(TruncInst &Trunc, InstCombiner &IC)
Given a vector that is bitcast to an integer, optionally logically right-shifted, and truncated...
static BinaryOperator * CreateFNegFMF(Value *Op, BinaryOperator *FMFSource, const Twine &Name="")
Definition: InstrTypes.h:420
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
This instruction extracts a single (scalar) element from a VectorType value.
void findDbgUsers(SmallVectorImpl< DbgInfoIntrinsic *> &DbgInsts, Value *V)
Finds the debug info intrinsics describing a value.
Definition: Local.cpp:1486
Value * CreateCast(Instruction::CastOps Op, Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1666
static GetElementPtrInst * CreateInBounds(Value *Ptr, ArrayRef< Value *> IdxList, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
Create an "inbounds" getelementptr.
Definition: Instructions.h:897
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
This class represents a truncation of floating point types.
unsigned getPrimitiveSizeInBits() const LLVM_READONLY
Return the basic size of this type if it is a primitive type.
Definition: Type.cpp:115
LLVM Value Representation.
Definition: Value.h:73
This file provides internal interfaces used to implement the InstCombine.
SelectPatternResult matchSelectPattern(Value *V, Value *&LHS, Value *&RHS, Instruction::CastOps *CastOp=nullptr, unsigned Depth=0)
Pattern match integer [SU]MIN, [SU]MAX and ABS idioms, returning the kind and providing the out param...
static VectorType * get(Type *ElementType, unsigned NumElements)
This static method is the primary way to construct an VectorType.
Definition: Type.cpp:593
static bool canEvaluateSExtd(Value *V, Type *Ty)
Return true if we can take the specified value and return it as type Ty without inserting any new cas...
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
Instruction * commonPointerCastTransforms(CastInst &CI)
Implement the transforms for cast of pointer (bitcast/ptrtoint)
Type * getElementType() const
Definition: DerivedTypes.h:360
bool hasOneUse() const
Return true if there is exactly one user of this value.
Definition: Value.h:412
static bool canAlwaysEvaluateInType(Value *V, Type *Ty)
Constants and extensions/truncates from the destination type are always free to be evaluated in that ...
bool isNonNegative() const
Returns true if this value is known to be non-negative.
Definition: KnownBits.h:99
unsigned countLeadingZeros() const
The APInt version of the countLeadingZeros functions in MathExtras.h.
Definition: APInt.h:1580
specific_intval m_SpecificInt(uint64_t V)
Match a specific integer value or vector with all elements equal to the value.
Definition: PatternMatch.h:567
bool isBigEndian() const
Definition: DataLayout.h:222
static Constant * get(LLVMContext &Context, ArrayRef< uint8_t > Elts)
get() constructors - Return a constant with vector type with an element count and element type matchi...
Definition: Constants.cpp:2495
Instruction * visitPtrToInt(PtrToIntInst &CI)
static ExtractElementInst * Create(Value *Vec, Value *Idx, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
#define LLVM_DEBUG(X)
Definition: Debug.h:119
op_range incoming_values()
This class represents an extension of floating point types.
bool isDoubleTy() const
Return true if this is &#39;double&#39;, a 64-bit IEEE fp type.
Definition: Type.h:150
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...
Type * getElementType() const
Definition: DerivedTypes.h:486
bool isNullValue() const
Determine if all bits are clear.
Definition: APInt.h:399
an instruction to allocate memory on the stack
Definition: Instructions.h:60
Instruction * visitFPTrunc(FPTruncInst &CI)
bool hasNoUnsignedWrap() const
Test whether this operation is known to never undergo unsigned overflow, aka the nuw property...
Definition: Operator.h:90