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  // Replace debug users of the eliminable cast by emitting debug values
272  // which refer to the new cast.
274  *CSrc, *Res, *std::next(CI.getIterator()),
275  [](DbgInfoIntrinsic &OldDII) { return OldDII.getExpression(); });
276 
277  return Res;
278  }
279  }
280 
281  if (auto *Sel = dyn_cast<SelectInst>(Src)) {
282  // We are casting a select. Try to fold the cast into the select, but only
283  // if the select does not have a compare instruction with matching operand
284  // types. Creating a select with operands that are different sizes than its
285  // condition may inhibit other folds and lead to worse codegen.
286  auto *Cmp = dyn_cast<CmpInst>(Sel->getCondition());
287  if (!Cmp || Cmp->getOperand(0)->getType() != Sel->getType())
288  if (Instruction *NV = FoldOpIntoSelect(CI, Sel))
289  return NV;
290  }
291 
292  // If we are casting a PHI, then fold the cast into the PHI.
293  if (auto *PN = dyn_cast<PHINode>(Src)) {
294  // Don't do this if it would create a PHI node with an illegal type from a
295  // legal type.
296  if (!Src->getType()->isIntegerTy() || !CI.getType()->isIntegerTy() ||
297  shouldChangeType(CI.getType(), Src->getType()))
298  if (Instruction *NV = foldOpIntoPhi(CI, PN))
299  return NV;
300  }
301 
302  return nullptr;
303 }
304 
305 /// Constants and extensions/truncates from the destination type are always
306 /// free to be evaluated in that type. This is a helper for canEvaluate*.
307 static bool canAlwaysEvaluateInType(Value *V, Type *Ty) {
308  if (isa<Constant>(V))
309  return true;
310  Value *X;
311  if ((match(V, m_ZExtOrSExt(m_Value(X))) || match(V, m_Trunc(m_Value(X)))) &&
312  X->getType() == Ty)
313  return true;
314 
315  return false;
316 }
317 
318 /// Filter out values that we can not evaluate in the destination type for free.
319 /// This is a helper for canEvaluate*.
320 static bool canNotEvaluateInType(Value *V, Type *Ty) {
321  assert(!isa<Constant>(V) && "Constant should already be handled.");
322  if (!isa<Instruction>(V))
323  return true;
324  // We don't extend or shrink something that has multiple uses -- doing so
325  // would require duplicating the instruction which isn't profitable.
326  if (!V->hasOneUse())
327  return true;
328 
329  return false;
330 }
331 
332 /// Return true if we can evaluate the specified expression tree as type Ty
333 /// instead of its larger type, and arrive with the same value.
334 /// This is used by code that tries to eliminate truncates.
335 ///
336 /// Ty will always be a type smaller than V. We should return true if trunc(V)
337 /// can be computed by computing V in the smaller type. If V is an instruction,
338 /// then trunc(inst(x,y)) can be computed as inst(trunc(x),trunc(y)), which only
339 /// makes sense if x and y can be efficiently truncated.
340 ///
341 /// This function works on both vectors and scalars.
342 ///
343 static bool canEvaluateTruncated(Value *V, Type *Ty, InstCombiner &IC,
344  Instruction *CxtI) {
345  if (canAlwaysEvaluateInType(V, Ty))
346  return true;
347  if (canNotEvaluateInType(V, Ty))
348  return false;
349 
350  auto *I = cast<Instruction>(V);
351  Type *OrigTy = V->getType();
352  switch (I->getOpcode()) {
353  case Instruction::Add:
354  case Instruction::Sub:
355  case Instruction::Mul:
356  case Instruction::And:
357  case Instruction::Or:
358  case Instruction::Xor:
359  // These operators can all arbitrarily be extended or truncated.
360  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI) &&
361  canEvaluateTruncated(I->getOperand(1), Ty, IC, CxtI);
362 
363  case Instruction::UDiv:
364  case Instruction::URem: {
365  // UDiv and URem can be truncated if all the truncated bits are zero.
366  uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
367  uint32_t BitWidth = Ty->getScalarSizeInBits();
368  assert(BitWidth < OrigBitWidth && "Unexpected bitwidths!");
369  APInt Mask = APInt::getBitsSetFrom(OrigBitWidth, BitWidth);
370  if (IC.MaskedValueIsZero(I->getOperand(0), Mask, 0, CxtI) &&
371  IC.MaskedValueIsZero(I->getOperand(1), Mask, 0, CxtI)) {
372  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI) &&
373  canEvaluateTruncated(I->getOperand(1), Ty, IC, CxtI);
374  }
375  break;
376  }
377  case Instruction::Shl: {
378  // If we are truncating the result of this SHL, and if it's a shift of a
379  // constant amount, we can always perform a SHL in a smaller type.
380  const APInt *Amt;
381  if (match(I->getOperand(1), m_APInt(Amt))) {
382  uint32_t BitWidth = Ty->getScalarSizeInBits();
383  if (Amt->getLimitedValue(BitWidth) < BitWidth)
384  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
385  }
386  break;
387  }
388  case Instruction::LShr: {
389  // If this is a truncate of a logical shr, we can truncate it to a smaller
390  // lshr iff we know that the bits we would otherwise be shifting in are
391  // already zeros.
392  const APInt *Amt;
393  if (match(I->getOperand(1), m_APInt(Amt))) {
394  uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
395  uint32_t BitWidth = Ty->getScalarSizeInBits();
396  if (Amt->getLimitedValue(BitWidth) < BitWidth &&
397  IC.MaskedValueIsZero(I->getOperand(0),
398  APInt::getBitsSetFrom(OrigBitWidth, BitWidth), 0, CxtI)) {
399  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
400  }
401  }
402  break;
403  }
404  case Instruction::AShr: {
405  // If this is a truncate of an arithmetic shr, we can truncate it to a
406  // smaller ashr iff we know that all the bits from the sign bit of the
407  // original type and the sign bit of the truncate type are similar.
408  // TODO: It is enough to check that the bits we would be shifting in are
409  // similar to sign bit of the truncate type.
410  const APInt *Amt;
411  if (match(I->getOperand(1), m_APInt(Amt))) {
412  uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
413  uint32_t BitWidth = Ty->getScalarSizeInBits();
414  if (Amt->getLimitedValue(BitWidth) < BitWidth &&
415  OrigBitWidth - BitWidth <
416  IC.ComputeNumSignBits(I->getOperand(0), 0, CxtI))
417  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
418  }
419  break;
420  }
421  case Instruction::Trunc:
422  // trunc(trunc(x)) -> trunc(x)
423  return true;
424  case Instruction::ZExt:
425  case Instruction::SExt:
426  // trunc(ext(x)) -> ext(x) if the source type is smaller than the new dest
427  // trunc(ext(x)) -> trunc(x) if the source type is larger than the new dest
428  return true;
429  case Instruction::Select: {
430  SelectInst *SI = cast<SelectInst>(I);
431  return canEvaluateTruncated(SI->getTrueValue(), Ty, IC, CxtI) &&
432  canEvaluateTruncated(SI->getFalseValue(), Ty, IC, CxtI);
433  }
434  case Instruction::PHI: {
435  // We can change a phi if we can change all operands. Note that we never
436  // get into trouble with cyclic PHIs here because we only consider
437  // instructions with a single use.
438  PHINode *PN = cast<PHINode>(I);
439  for (Value *IncValue : PN->incoming_values())
440  if (!canEvaluateTruncated(IncValue, Ty, IC, CxtI))
441  return false;
442  return true;
443  }
444  default:
445  // TODO: Can handle more cases here.
446  break;
447  }
448 
449  return false;
450 }
451 
452 /// Given a vector that is bitcast to an integer, optionally logically
453 /// right-shifted, and truncated, convert it to an extractelement.
454 /// Example (big endian):
455 /// trunc (lshr (bitcast <4 x i32> %X to i128), 32) to i32
456 /// --->
457 /// extractelement <4 x i32> %X, 1
459  Value *TruncOp = Trunc.getOperand(0);
460  Type *DestType = Trunc.getType();
461  if (!TruncOp->hasOneUse() || !isa<IntegerType>(DestType))
462  return nullptr;
463 
464  Value *VecInput = nullptr;
465  ConstantInt *ShiftVal = nullptr;
466  if (!match(TruncOp, m_CombineOr(m_BitCast(m_Value(VecInput)),
467  m_LShr(m_BitCast(m_Value(VecInput)),
468  m_ConstantInt(ShiftVal)))) ||
469  !isa<VectorType>(VecInput->getType()))
470  return nullptr;
471 
472  VectorType *VecType = cast<VectorType>(VecInput->getType());
473  unsigned VecWidth = VecType->getPrimitiveSizeInBits();
474  unsigned DestWidth = DestType->getPrimitiveSizeInBits();
475  unsigned ShiftAmount = ShiftVal ? ShiftVal->getZExtValue() : 0;
476 
477  if ((VecWidth % DestWidth != 0) || (ShiftAmount % DestWidth != 0))
478  return nullptr;
479 
480  // If the element type of the vector doesn't match the result type,
481  // bitcast it to a vector type that we can extract from.
482  unsigned NumVecElts = VecWidth / DestWidth;
483  if (VecType->getElementType() != DestType) {
484  VecType = VectorType::get(DestType, NumVecElts);
485  VecInput = IC.Builder.CreateBitCast(VecInput, VecType, "bc");
486  }
487 
488  unsigned Elt = ShiftAmount / DestWidth;
489  if (IC.getDataLayout().isBigEndian())
490  Elt = NumVecElts - 1 - Elt;
491 
492  return ExtractElementInst::Create(VecInput, IC.Builder.getInt32(Elt));
493 }
494 
495 /// Rotate left/right may occur in a wider type than necessary because of type
496 /// promotion rules. Try to narrow all of the component instructions.
497 Instruction *InstCombiner::narrowRotate(TruncInst &Trunc) {
498  assert((isa<VectorType>(Trunc.getSrcTy()) ||
499  shouldChangeType(Trunc.getSrcTy(), Trunc.getType())) &&
500  "Don't narrow to an illegal scalar type");
501 
502  // First, find an or'd pair of opposite shifts with the same shifted operand:
503  // trunc (or (lshr ShVal, ShAmt0), (shl ShVal, ShAmt1))
504  Value *Or0, *Or1;
505  if (!match(Trunc.getOperand(0), m_OneUse(m_Or(m_Value(Or0), m_Value(Or1)))))
506  return nullptr;
507 
508  Value *ShVal, *ShAmt0, *ShAmt1;
509  if (!match(Or0, m_OneUse(m_LogicalShift(m_Value(ShVal), m_Value(ShAmt0)))) ||
510  !match(Or1, m_OneUse(m_LogicalShift(m_Specific(ShVal), m_Value(ShAmt1)))))
511  return nullptr;
512 
513  auto ShiftOpcode0 = cast<BinaryOperator>(Or0)->getOpcode();
514  auto ShiftOpcode1 = cast<BinaryOperator>(Or1)->getOpcode();
515  if (ShiftOpcode0 == ShiftOpcode1)
516  return nullptr;
517 
518  // The shift amounts must add up to the narrow bit width.
519  Value *ShAmt;
520  bool SubIsOnLHS;
521  Type *DestTy = Trunc.getType();
522  unsigned NarrowWidth = DestTy->getScalarSizeInBits();
523  if (match(ShAmt0,
524  m_OneUse(m_Sub(m_SpecificInt(NarrowWidth), m_Specific(ShAmt1))))) {
525  ShAmt = ShAmt1;
526  SubIsOnLHS = true;
527  } else if (match(ShAmt1, m_OneUse(m_Sub(m_SpecificInt(NarrowWidth),
528  m_Specific(ShAmt0))))) {
529  ShAmt = ShAmt0;
530  SubIsOnLHS = false;
531  } else {
532  return nullptr;
533  }
534 
535  // The shifted value must have high zeros in the wide type. Typically, this
536  // will be a zext, but it could also be the result of an 'and' or 'shift'.
537  unsigned WideWidth = Trunc.getSrcTy()->getScalarSizeInBits();
538  APInt HiBitMask = APInt::getHighBitsSet(WideWidth, WideWidth - NarrowWidth);
539  if (!MaskedValueIsZero(ShVal, HiBitMask, 0, &Trunc))
540  return nullptr;
541 
542  // We have an unnecessarily wide rotate!
543  // trunc (or (lshr ShVal, ShAmt), (shl ShVal, BitWidth - ShAmt))
544  // Narrow it down to eliminate the zext/trunc:
545  // or (lshr trunc(ShVal), ShAmt0'), (shl trunc(ShVal), ShAmt1')
546  Value *NarrowShAmt = Builder.CreateTrunc(ShAmt, DestTy);
547  Value *NegShAmt = Builder.CreateNeg(NarrowShAmt);
548 
549  // Mask both shift amounts to ensure there's no UB from oversized shifts.
550  Constant *MaskC = ConstantInt::get(DestTy, NarrowWidth - 1);
551  Value *MaskedShAmt = Builder.CreateAnd(NarrowShAmt, MaskC);
552  Value *MaskedNegShAmt = Builder.CreateAnd(NegShAmt, MaskC);
553 
554  // Truncate the original value and use narrow ops.
555  Value *X = Builder.CreateTrunc(ShVal, DestTy);
556  Value *NarrowShAmt0 = SubIsOnLHS ? MaskedNegShAmt : MaskedShAmt;
557  Value *NarrowShAmt1 = SubIsOnLHS ? MaskedShAmt : MaskedNegShAmt;
558  Value *NarrowSh0 = Builder.CreateBinOp(ShiftOpcode0, X, NarrowShAmt0);
559  Value *NarrowSh1 = Builder.CreateBinOp(ShiftOpcode1, X, NarrowShAmt1);
560  return BinaryOperator::CreateOr(NarrowSh0, NarrowSh1);
561 }
562 
563 /// Try to narrow the width of math or bitwise logic instructions by pulling a
564 /// truncate ahead of binary operators.
565 /// TODO: Transforms for truncated shifts should be moved into here.
566 Instruction *InstCombiner::narrowBinOp(TruncInst &Trunc) {
567  Type *SrcTy = Trunc.getSrcTy();
568  Type *DestTy = Trunc.getType();
569  if (!isa<VectorType>(SrcTy) && !shouldChangeType(SrcTy, DestTy))
570  return nullptr;
571 
572  BinaryOperator *BinOp;
573  if (!match(Trunc.getOperand(0), m_OneUse(m_BinOp(BinOp))))
574  return nullptr;
575 
576  Value *BinOp0 = BinOp->getOperand(0);
577  Value *BinOp1 = BinOp->getOperand(1);
578  switch (BinOp->getOpcode()) {
579  case Instruction::And:
580  case Instruction::Or:
581  case Instruction::Xor:
582  case Instruction::Add:
583  case Instruction::Sub:
584  case Instruction::Mul: {
585  Constant *C;
586  if (match(BinOp0, m_Constant(C))) {
587  // trunc (binop C, X) --> binop (trunc C', X)
588  Constant *NarrowC = ConstantExpr::getTrunc(C, DestTy);
589  Value *TruncX = Builder.CreateTrunc(BinOp1, DestTy);
590  return BinaryOperator::Create(BinOp->getOpcode(), NarrowC, TruncX);
591  }
592  if (match(BinOp1, m_Constant(C))) {
593  // trunc (binop X, C) --> binop (trunc X, C')
594  Constant *NarrowC = ConstantExpr::getTrunc(C, DestTy);
595  Value *TruncX = Builder.CreateTrunc(BinOp0, DestTy);
596  return BinaryOperator::Create(BinOp->getOpcode(), TruncX, NarrowC);
597  }
598  Value *X;
599  if (match(BinOp0, m_ZExtOrSExt(m_Value(X))) && X->getType() == DestTy) {
600  // trunc (binop (ext X), Y) --> binop X, (trunc Y)
601  Value *NarrowOp1 = Builder.CreateTrunc(BinOp1, DestTy);
602  return BinaryOperator::Create(BinOp->getOpcode(), X, NarrowOp1);
603  }
604  if (match(BinOp1, m_ZExtOrSExt(m_Value(X))) && X->getType() == DestTy) {
605  // trunc (binop Y, (ext X)) --> binop (trunc Y), X
606  Value *NarrowOp0 = Builder.CreateTrunc(BinOp0, DestTy);
607  return BinaryOperator::Create(BinOp->getOpcode(), NarrowOp0, X);
608  }
609  break;
610  }
611 
612  default: break;
613  }
614 
615  if (Instruction *NarrowOr = narrowRotate(Trunc))
616  return NarrowOr;
617 
618  return nullptr;
619 }
620 
621 /// Try to narrow the width of a splat shuffle. This could be generalized to any
622 /// shuffle with a constant operand, but we limit the transform to avoid
623 /// creating a shuffle type that targets may not be able to lower effectively.
625  InstCombiner::BuilderTy &Builder) {
626  auto *Shuf = dyn_cast<ShuffleVectorInst>(Trunc.getOperand(0));
627  if (Shuf && Shuf->hasOneUse() && isa<UndefValue>(Shuf->getOperand(1)) &&
628  Shuf->getMask()->getSplatValue() &&
629  Shuf->getType() == Shuf->getOperand(0)->getType()) {
630  // trunc (shuf X, Undef, SplatMask) --> shuf (trunc X), Undef, SplatMask
631  Constant *NarrowUndef = UndefValue::get(Trunc.getType());
632  Value *NarrowOp = Builder.CreateTrunc(Shuf->getOperand(0), Trunc.getType());
633  return new ShuffleVectorInst(NarrowOp, NarrowUndef, Shuf->getMask());
634  }
635 
636  return nullptr;
637 }
638 
639 /// Try to narrow the width of an insert element. This could be generalized for
640 /// any vector constant, but we limit the transform to insertion into undef to
641 /// avoid potential backend problems from unsupported insertion widths. This
642 /// could also be extended to handle the case of inserting a scalar constant
643 /// into a vector variable.
645  InstCombiner::BuilderTy &Builder) {
646  Instruction::CastOps Opcode = Trunc.getOpcode();
647  assert((Opcode == Instruction::Trunc || Opcode == Instruction::FPTrunc) &&
648  "Unexpected instruction for shrinking");
649 
650  auto *InsElt = dyn_cast<InsertElementInst>(Trunc.getOperand(0));
651  if (!InsElt || !InsElt->hasOneUse())
652  return nullptr;
653 
654  Type *DestTy = Trunc.getType();
655  Type *DestScalarTy = DestTy->getScalarType();
656  Value *VecOp = InsElt->getOperand(0);
657  Value *ScalarOp = InsElt->getOperand(1);
658  Value *Index = InsElt->getOperand(2);
659 
660  if (isa<UndefValue>(VecOp)) {
661  // trunc (inselt undef, X, Index) --> inselt undef, (trunc X), Index
662  // fptrunc (inselt undef, X, Index) --> inselt undef, (fptrunc X), Index
663  UndefValue *NarrowUndef = UndefValue::get(DestTy);
664  Value *NarrowOp = Builder.CreateCast(Opcode, ScalarOp, DestScalarTy);
665  return InsertElementInst::Create(NarrowUndef, NarrowOp, Index);
666  }
667 
668  return nullptr;
669 }
670 
672  if (Instruction *Result = commonCastTransforms(CI))
673  return Result;
674 
675  // Test if the trunc is the user of a select which is part of a
676  // minimum or maximum operation. If so, don't do any more simplification.
677  // Even simplifying demanded bits can break the canonical form of a
678  // min/max.
679  Value *LHS, *RHS;
680  if (SelectInst *SI = dyn_cast<SelectInst>(CI.getOperand(0)))
681  if (matchSelectPattern(SI, LHS, RHS).Flavor != SPF_UNKNOWN)
682  return nullptr;
683 
684  // See if we can simplify any instructions used by the input whose sole
685  // purpose is to compute bits we don't care about.
686  if (SimplifyDemandedInstructionBits(CI))
687  return &CI;
688 
689  Value *Src = CI.getOperand(0);
690  Type *DestTy = CI.getType(), *SrcTy = Src->getType();
691 
692  // Attempt to truncate the entire input expression tree to the destination
693  // type. Only do this if the dest type is a simple type, don't convert the
694  // expression tree to something weird like i93 unless the source is also
695  // strange.
696  if ((DestTy->isVectorTy() || shouldChangeType(SrcTy, DestTy)) &&
697  canEvaluateTruncated(Src, DestTy, *this, &CI)) {
698 
699  // If this cast is a truncate, evaluting in a different type always
700  // eliminates the cast, so it is always a win.
701  LLVM_DEBUG(
702  dbgs() << "ICE: EvaluateInDifferentType converting expression type"
703  " to avoid cast: "
704  << CI << '\n');
705  Value *Res = EvaluateInDifferentType(Src, DestTy, false);
706  assert(Res->getType() == DestTy);
707  return replaceInstUsesWith(CI, Res);
708  }
709 
710  // Canonicalize trunc x to i1 -> (icmp ne (and x, 1), 0), likewise for vector.
711  if (DestTy->getScalarSizeInBits() == 1) {
712  Constant *One = ConstantInt::get(SrcTy, 1);
713  Src = Builder.CreateAnd(Src, One);
714  Value *Zero = Constant::getNullValue(Src->getType());
715  return new ICmpInst(ICmpInst::ICMP_NE, Src, Zero);
716  }
717 
718  // FIXME: Maybe combine the next two transforms to handle the no cast case
719  // more efficiently. Support vector types. Cleanup code by using m_OneUse.
720 
721  // Transform trunc(lshr (zext A), Cst) to eliminate one type conversion.
722  Value *A = nullptr; ConstantInt *Cst = nullptr;
723  if (Src->hasOneUse() &&
724  match(Src, m_LShr(m_ZExt(m_Value(A)), m_ConstantInt(Cst)))) {
725  // We have three types to worry about here, the type of A, the source of
726  // the truncate (MidSize), and the destination of the truncate. We know that
727  // ASize < MidSize and MidSize > ResultSize, but don't know the relation
728  // between ASize and ResultSize.
729  unsigned ASize = A->getType()->getPrimitiveSizeInBits();
730 
731  // If the shift amount is larger than the size of A, then the result is
732  // known to be zero because all the input bits got shifted out.
733  if (Cst->getZExtValue() >= ASize)
734  return replaceInstUsesWith(CI, Constant::getNullValue(DestTy));
735 
736  // Since we're doing an lshr and a zero extend, and know that the shift
737  // amount is smaller than ASize, it is always safe to do the shift in A's
738  // type, then zero extend or truncate to the result.
739  Value *Shift = Builder.CreateLShr(A, Cst->getZExtValue());
740  Shift->takeName(Src);
741  return CastInst::CreateIntegerCast(Shift, DestTy, false);
742  }
743 
744  // FIXME: We should canonicalize to zext/trunc and remove this transform.
745  // Transform trunc(lshr (sext A), Cst) to ashr A, Cst to eliminate type
746  // conversion.
747  // It works because bits coming from sign extension have the same value as
748  // the sign bit of the original value; performing ashr instead of lshr
749  // generates bits of the same value as the sign bit.
750  if (Src->hasOneUse() &&
751  match(Src, m_LShr(m_SExt(m_Value(A)), m_ConstantInt(Cst)))) {
752  Value *SExt = cast<Instruction>(Src)->getOperand(0);
753  const unsigned SExtSize = SExt->getType()->getPrimitiveSizeInBits();
754  const unsigned ASize = A->getType()->getPrimitiveSizeInBits();
755  const unsigned CISize = CI.getType()->getPrimitiveSizeInBits();
756  const unsigned MaxAmt = SExtSize - std::max(CISize, ASize);
757  unsigned ShiftAmt = Cst->getZExtValue();
758 
759  // This optimization can be only performed when zero bits generated by
760  // the original lshr aren't pulled into the value after truncation, so we
761  // can only shift by values no larger than the number of extension bits.
762  // FIXME: Instead of bailing when the shift is too large, use and to clear
763  // the extra bits.
764  if (ShiftAmt <= MaxAmt) {
765  if (CISize == ASize)
766  return BinaryOperator::CreateAShr(A, ConstantInt::get(CI.getType(),
767  std::min(ShiftAmt, ASize - 1)));
768  if (SExt->hasOneUse()) {
769  Value *Shift = Builder.CreateAShr(A, std::min(ShiftAmt, ASize - 1));
770  Shift->takeName(Src);
771  return CastInst::CreateIntegerCast(Shift, CI.getType(), true);
772  }
773  }
774  }
775 
776  if (Instruction *I = narrowBinOp(CI))
777  return I;
778 
779  if (Instruction *I = shrinkSplatShuffle(CI, Builder))
780  return I;
781 
782  if (Instruction *I = shrinkInsertElt(CI, Builder))
783  return I;
784 
785  if (Src->hasOneUse() && isa<IntegerType>(SrcTy) &&
786  shouldChangeType(SrcTy, DestTy)) {
787  // Transform "trunc (shl X, cst)" -> "shl (trunc X), cst" so long as the
788  // dest type is native and cst < dest size.
789  if (match(Src, m_Shl(m_Value(A), m_ConstantInt(Cst))) &&
790  !match(A, m_Shr(m_Value(), m_Constant()))) {
791  // Skip shifts of shift by constants. It undoes a combine in
792  // FoldShiftByConstant and is the extend in reg pattern.
793  const unsigned DestSize = DestTy->getScalarSizeInBits();
794  if (Cst->getValue().ult(DestSize)) {
795  Value *NewTrunc = Builder.CreateTrunc(A, DestTy, A->getName() + ".tr");
796 
797  return BinaryOperator::Create(
798  Instruction::Shl, NewTrunc,
799  ConstantInt::get(DestTy, Cst->getValue().trunc(DestSize)));
800  }
801  }
802  }
803 
804  if (Instruction *I = foldVecTruncToExtElt(CI, *this))
805  return I;
806 
807  return nullptr;
808 }
809 
810 Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, ZExtInst &CI,
811  bool DoTransform) {
812  // If we are just checking for a icmp eq of a single bit and zext'ing it
813  // to an integer, then shift the bit to the appropriate place and then
814  // cast to integer to avoid the comparison.
815  const APInt *Op1CV;
816  if (match(ICI->getOperand(1), m_APInt(Op1CV))) {
817 
818  // zext (x <s 0) to i32 --> x>>u31 true if signbit set.
819  // zext (x >s -1) to i32 --> (x>>u31)^1 true if signbit clear.
820  if ((ICI->getPredicate() == ICmpInst::ICMP_SLT && Op1CV->isNullValue()) ||
821  (ICI->getPredicate() == ICmpInst::ICMP_SGT && Op1CV->isAllOnesValue())) {
822  if (!DoTransform) return ICI;
823 
824  Value *In = ICI->getOperand(0);
825  Value *Sh = ConstantInt::get(In->getType(),
826  In->getType()->getScalarSizeInBits() - 1);
827  In = Builder.CreateLShr(In, Sh, In->getName() + ".lobit");
828  if (In->getType() != CI.getType())
829  In = Builder.CreateIntCast(In, CI.getType(), false /*ZExt*/);
830 
831  if (ICI->getPredicate() == ICmpInst::ICMP_SGT) {
832  Constant *One = ConstantInt::get(In->getType(), 1);
833  In = Builder.CreateXor(In, One, In->getName() + ".not");
834  }
835 
836  return replaceInstUsesWith(CI, In);
837  }
838 
839  // zext (X == 0) to i32 --> X^1 iff X has only the low bit set.
840  // zext (X == 0) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
841  // zext (X == 1) to i32 --> X iff X has only the low bit set.
842  // zext (X == 2) to i32 --> X>>1 iff X has only the 2nd bit set.
843  // zext (X != 0) to i32 --> X iff X has only the low bit set.
844  // zext (X != 0) to i32 --> X>>1 iff X has only the 2nd bit set.
845  // zext (X != 1) to i32 --> X^1 iff X has only the low bit set.
846  // zext (X != 2) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
847  if ((Op1CV->isNullValue() || Op1CV->isPowerOf2()) &&
848  // This only works for EQ and NE
849  ICI->isEquality()) {
850  // If Op1C some other power of two, convert:
851  KnownBits Known = computeKnownBits(ICI->getOperand(0), 0, &CI);
852 
853  APInt KnownZeroMask(~Known.Zero);
854  if (KnownZeroMask.isPowerOf2()) { // Exactly 1 possible 1?
855  if (!DoTransform) return ICI;
856 
857  bool isNE = ICI->getPredicate() == ICmpInst::ICMP_NE;
858  if (!Op1CV->isNullValue() && (*Op1CV != KnownZeroMask)) {
859  // (X&4) == 2 --> false
860  // (X&4) != 2 --> true
861  Constant *Res = ConstantInt::get(CI.getType(), isNE);
862  return replaceInstUsesWith(CI, Res);
863  }
864 
865  uint32_t ShAmt = KnownZeroMask.logBase2();
866  Value *In = ICI->getOperand(0);
867  if (ShAmt) {
868  // Perform a logical shr by shiftamt.
869  // Insert the shift to put the result in the low bit.
870  In = Builder.CreateLShr(In, ConstantInt::get(In->getType(), ShAmt),
871  In->getName() + ".lobit");
872  }
873 
874  if (!Op1CV->isNullValue() == isNE) { // Toggle the low bit.
875  Constant *One = ConstantInt::get(In->getType(), 1);
876  In = Builder.CreateXor(In, One);
877  }
878 
879  if (CI.getType() == In->getType())
880  return replaceInstUsesWith(CI, In);
881 
882  Value *IntCast = Builder.CreateIntCast(In, CI.getType(), false);
883  return replaceInstUsesWith(CI, IntCast);
884  }
885  }
886  }
887 
888  // icmp ne A, B is equal to xor A, B when A and B only really have one bit.
889  // It is also profitable to transform icmp eq into not(xor(A, B)) because that
890  // may lead to additional simplifications.
891  if (ICI->isEquality() && CI.getType() == ICI->getOperand(0)->getType()) {
892  if (IntegerType *ITy = dyn_cast<IntegerType>(CI.getType())) {
893  Value *LHS = ICI->getOperand(0);
894  Value *RHS = ICI->getOperand(1);
895 
896  KnownBits KnownLHS = computeKnownBits(LHS, 0, &CI);
897  KnownBits KnownRHS = computeKnownBits(RHS, 0, &CI);
898 
899  if (KnownLHS.Zero == KnownRHS.Zero && KnownLHS.One == KnownRHS.One) {
900  APInt KnownBits = KnownLHS.Zero | KnownLHS.One;
901  APInt UnknownBit = ~KnownBits;
902  if (UnknownBit.countPopulation() == 1) {
903  if (!DoTransform) return ICI;
904 
905  Value *Result = Builder.CreateXor(LHS, RHS);
906 
907  // Mask off any bits that are set and won't be shifted away.
908  if (KnownLHS.One.uge(UnknownBit))
909  Result = Builder.CreateAnd(Result,
910  ConstantInt::get(ITy, UnknownBit));
911 
912  // Shift the bit we're testing down to the lsb.
913  Result = Builder.CreateLShr(
914  Result, ConstantInt::get(ITy, UnknownBit.countTrailingZeros()));
915 
916  if (ICI->getPredicate() == ICmpInst::ICMP_EQ)
917  Result = Builder.CreateXor(Result, ConstantInt::get(ITy, 1));
918  Result->takeName(ICI);
919  return replaceInstUsesWith(CI, Result);
920  }
921  }
922  }
923  }
924 
925  return nullptr;
926 }
927 
928 /// Determine if the specified value can be computed in the specified wider type
929 /// and produce the same low bits. If not, return false.
930 ///
931 /// If this function returns true, it can also return a non-zero number of bits
932 /// (in BitsToClear) which indicates that the value it computes is correct for
933 /// the zero extend, but that the additional BitsToClear bits need to be zero'd
934 /// out. For example, to promote something like:
935 ///
936 /// %B = trunc i64 %A to i32
937 /// %C = lshr i32 %B, 8
938 /// %E = zext i32 %C to i64
939 ///
940 /// CanEvaluateZExtd for the 'lshr' will return true, and BitsToClear will be
941 /// set to 8 to indicate that the promoted value needs to have bits 24-31
942 /// cleared in addition to bits 32-63. Since an 'and' will be generated to
943 /// clear the top bits anyway, doing this has no extra cost.
944 ///
945 /// This function works on both vectors and scalars.
946 static bool canEvaluateZExtd(Value *V, Type *Ty, unsigned &BitsToClear,
947  InstCombiner &IC, Instruction *CxtI) {
948  BitsToClear = 0;
949  if (canAlwaysEvaluateInType(V, Ty))
950  return true;
951  if (canNotEvaluateInType(V, Ty))
952  return false;
953 
954  auto *I = cast<Instruction>(V);
955  unsigned Tmp;
956  switch (I->getOpcode()) {
957  case Instruction::ZExt: // zext(zext(x)) -> zext(x).
958  case Instruction::SExt: // zext(sext(x)) -> sext(x).
959  case Instruction::Trunc: // zext(trunc(x)) -> trunc(x) or zext(x)
960  return true;
961  case Instruction::And:
962  case Instruction::Or:
963  case Instruction::Xor:
964  case Instruction::Add:
965  case Instruction::Sub:
966  case Instruction::Mul:
967  if (!canEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI) ||
968  !canEvaluateZExtd(I->getOperand(1), Ty, Tmp, IC, CxtI))
969  return false;
970  // These can all be promoted if neither operand has 'bits to clear'.
971  if (BitsToClear == 0 && Tmp == 0)
972  return true;
973 
974  // If the operation is an AND/OR/XOR and the bits to clear are zero in the
975  // other side, BitsToClear is ok.
976  if (Tmp == 0 && I->isBitwiseLogicOp()) {
977  // We use MaskedValueIsZero here for generality, but the case we care
978  // about the most is constant RHS.
979  unsigned VSize = V->getType()->getScalarSizeInBits();
980  if (IC.MaskedValueIsZero(I->getOperand(1),
981  APInt::getHighBitsSet(VSize, BitsToClear),
982  0, CxtI)) {
983  // If this is an And instruction and all of the BitsToClear are
984  // known to be zero we can reset BitsToClear.
985  if (I->getOpcode() == Instruction::And)
986  BitsToClear = 0;
987  return true;
988  }
989  }
990 
991  // Otherwise, we don't know how to analyze this BitsToClear case yet.
992  return false;
993 
994  case Instruction::Shl: {
995  // We can promote shl(x, cst) if we can promote x. Since shl overwrites the
996  // upper bits we can reduce BitsToClear by the shift amount.
997  const APInt *Amt;
998  if (match(I->getOperand(1), m_APInt(Amt))) {
999  if (!canEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI))
1000  return false;
1001  uint64_t ShiftAmt = Amt->getZExtValue();
1002  BitsToClear = ShiftAmt < BitsToClear ? BitsToClear - ShiftAmt : 0;
1003  return true;
1004  }
1005  return false;
1006  }
1007  case Instruction::LShr: {
1008  // We can promote lshr(x, cst) if we can promote x. This requires the
1009  // ultimate 'and' to clear out the high zero bits we're clearing out though.
1010  const APInt *Amt;
1011  if (match(I->getOperand(1), m_APInt(Amt))) {
1012  if (!canEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI))
1013  return false;
1014  BitsToClear += Amt->getZExtValue();
1015  if (BitsToClear > V->getType()->getScalarSizeInBits())
1016  BitsToClear = V->getType()->getScalarSizeInBits();
1017  return true;
1018  }
1019  // Cannot promote variable LSHR.
1020  return false;
1021  }
1022  case Instruction::Select:
1023  if (!canEvaluateZExtd(I->getOperand(1), Ty, Tmp, IC, CxtI) ||
1024  !canEvaluateZExtd(I->getOperand(2), Ty, BitsToClear, IC, CxtI) ||
1025  // TODO: If important, we could handle the case when the BitsToClear are
1026  // known zero in the disagreeing side.
1027  Tmp != BitsToClear)
1028  return false;
1029  return true;
1030 
1031  case Instruction::PHI: {
1032  // We can change a phi if we can change all operands. Note that we never
1033  // get into trouble with cyclic PHIs here because we only consider
1034  // instructions with a single use.
1035  PHINode *PN = cast<PHINode>(I);
1036  if (!canEvaluateZExtd(PN->getIncomingValue(0), Ty, BitsToClear, IC, CxtI))
1037  return false;
1038  for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i)
1039  if (!canEvaluateZExtd(PN->getIncomingValue(i), Ty, Tmp, IC, CxtI) ||
1040  // TODO: If important, we could handle the case when the BitsToClear
1041  // are known zero in the disagreeing input.
1042  Tmp != BitsToClear)
1043  return false;
1044  return true;
1045  }
1046  default:
1047  // TODO: Can handle more cases here.
1048  return false;
1049  }
1050 }
1051 
1053  // If this zero extend is only used by a truncate, let the truncate be
1054  // eliminated before we try to optimize this zext.
1055  if (CI.hasOneUse() && isa<TruncInst>(CI.user_back()))
1056  return nullptr;
1057 
1058  // If one of the common conversion will work, do it.
1059  if (Instruction *Result = commonCastTransforms(CI))
1060  return Result;
1061 
1062  Value *Src = CI.getOperand(0);
1063  Type *SrcTy = Src->getType(), *DestTy = CI.getType();
1064 
1065  // Attempt to extend the entire input expression tree to the destination
1066  // type. Only do this if the dest type is a simple type, don't convert the
1067  // expression tree to something weird like i93 unless the source is also
1068  // strange.
1069  unsigned BitsToClear;
1070  if ((DestTy->isVectorTy() || shouldChangeType(SrcTy, DestTy)) &&
1071  canEvaluateZExtd(Src, DestTy, BitsToClear, *this, &CI)) {
1072  assert(BitsToClear <= SrcTy->getScalarSizeInBits() &&
1073  "Can't clear more bits than in SrcTy");
1074 
1075  // Okay, we can transform this! Insert the new expression now.
1076  LLVM_DEBUG(
1077  dbgs() << "ICE: EvaluateInDifferentType converting expression type"
1078  " to avoid zero extend: "
1079  << CI << '\n');
1080  Value *Res = EvaluateInDifferentType(Src, DestTy, false);
1081  assert(Res->getType() == DestTy);
1082 
1083  uint32_t SrcBitsKept = SrcTy->getScalarSizeInBits()-BitsToClear;
1084  uint32_t DestBitSize = DestTy->getScalarSizeInBits();
1085 
1086  // If the high bits are already filled with zeros, just replace this
1087  // cast with the result.
1088  if (MaskedValueIsZero(Res,
1089  APInt::getHighBitsSet(DestBitSize,
1090  DestBitSize-SrcBitsKept),
1091  0, &CI))
1092  return replaceInstUsesWith(CI, Res);
1093 
1094  // We need to emit an AND to clear the high bits.
1095  Constant *C = ConstantInt::get(Res->getType(),
1096  APInt::getLowBitsSet(DestBitSize, SrcBitsKept));
1097  return BinaryOperator::CreateAnd(Res, C);
1098  }
1099 
1100  // If this is a TRUNC followed by a ZEXT then we are dealing with integral
1101  // types and if the sizes are just right we can convert this into a logical
1102  // 'and' which will be much cheaper than the pair of casts.
1103  if (TruncInst *CSrc = dyn_cast<TruncInst>(Src)) { // A->B->C cast
1104  // TODO: Subsume this into EvaluateInDifferentType.
1105 
1106  // Get the sizes of the types involved. We know that the intermediate type
1107  // will be smaller than A or C, but don't know the relation between A and C.
1108  Value *A = CSrc->getOperand(0);
1109  unsigned SrcSize = A->getType()->getScalarSizeInBits();
1110  unsigned MidSize = CSrc->getType()->getScalarSizeInBits();
1111  unsigned DstSize = CI.getType()->getScalarSizeInBits();
1112  // If we're actually extending zero bits, then if
1113  // SrcSize < DstSize: zext(a & mask)
1114  // SrcSize == DstSize: a & mask
1115  // SrcSize > DstSize: trunc(a) & mask
1116  if (SrcSize < DstSize) {
1117  APInt AndValue(APInt::getLowBitsSet(SrcSize, MidSize));
1118  Constant *AndConst = ConstantInt::get(A->getType(), AndValue);
1119  Value *And = Builder.CreateAnd(A, AndConst, CSrc->getName() + ".mask");
1120  return new ZExtInst(And, CI.getType());
1121  }
1122 
1123  if (SrcSize == DstSize) {
1124  APInt AndValue(APInt::getLowBitsSet(SrcSize, MidSize));
1125  return BinaryOperator::CreateAnd(A, ConstantInt::get(A->getType(),
1126  AndValue));
1127  }
1128  if (SrcSize > DstSize) {
1129  Value *Trunc = Builder.CreateTrunc(A, CI.getType());
1130  APInt AndValue(APInt::getLowBitsSet(DstSize, MidSize));
1131  return BinaryOperator::CreateAnd(Trunc,
1132  ConstantInt::get(Trunc->getType(),
1133  AndValue));
1134  }
1135  }
1136 
1137  if (ICmpInst *ICI = dyn_cast<ICmpInst>(Src))
1138  return transformZExtICmp(ICI, CI);
1139 
1140  BinaryOperator *SrcI = dyn_cast<BinaryOperator>(Src);
1141  if (SrcI && SrcI->getOpcode() == Instruction::Or) {
1142  // zext (or icmp, icmp) -> or (zext icmp), (zext icmp) if at least one
1143  // of the (zext icmp) can be eliminated. If so, immediately perform the
1144  // according elimination.
1145  ICmpInst *LHS = dyn_cast<ICmpInst>(SrcI->getOperand(0));
1146  ICmpInst *RHS = dyn_cast<ICmpInst>(SrcI->getOperand(1));
1147  if (LHS && RHS && LHS->hasOneUse() && RHS->hasOneUse() &&
1148  (transformZExtICmp(LHS, CI, false) ||
1149  transformZExtICmp(RHS, CI, false))) {
1150  // zext (or icmp, icmp) -> or (zext icmp), (zext icmp)
1151  Value *LCast = Builder.CreateZExt(LHS, CI.getType(), LHS->getName());
1152  Value *RCast = Builder.CreateZExt(RHS, CI.getType(), RHS->getName());
1153  BinaryOperator *Or = BinaryOperator::Create(Instruction::Or, LCast, RCast);
1154 
1155  // Perform the elimination.
1156  if (auto *LZExt = dyn_cast<ZExtInst>(LCast))
1157  transformZExtICmp(LHS, *LZExt);
1158  if (auto *RZExt = dyn_cast<ZExtInst>(RCast))
1159  transformZExtICmp(RHS, *RZExt);
1160 
1161  return Or;
1162  }
1163  }
1164 
1165  // zext(trunc(X) & C) -> (X & zext(C)).
1166  Constant *C;
1167  Value *X;
1168  if (SrcI &&
1169  match(SrcI, m_OneUse(m_And(m_Trunc(m_Value(X)), m_Constant(C)))) &&
1170  X->getType() == CI.getType())
1171  return BinaryOperator::CreateAnd(X, ConstantExpr::getZExt(C, CI.getType()));
1172 
1173  // zext((trunc(X) & C) ^ C) -> ((X & zext(C)) ^ zext(C)).
1174  Value *And;
1175  if (SrcI && match(SrcI, m_OneUse(m_Xor(m_Value(And), m_Constant(C)))) &&
1176  match(And, m_OneUse(m_And(m_Trunc(m_Value(X)), m_Specific(C)))) &&
1177  X->getType() == CI.getType()) {
1178  Constant *ZC = ConstantExpr::getZExt(C, CI.getType());
1179  return BinaryOperator::CreateXor(Builder.CreateAnd(X, ZC), ZC);
1180  }
1181 
1182  return nullptr;
1183 }
1184 
1185 /// Transform (sext icmp) to bitwise / integer operations to eliminate the icmp.
1186 Instruction *InstCombiner::transformSExtICmp(ICmpInst *ICI, Instruction &CI) {
1187  Value *Op0 = ICI->getOperand(0), *Op1 = ICI->getOperand(1);
1188  ICmpInst::Predicate Pred = ICI->getPredicate();
1189 
1190  // Don't bother if Op1 isn't of vector or integer type.
1191  if (!Op1->getType()->isIntOrIntVectorTy())
1192  return nullptr;
1193 
1194  if ((Pred == ICmpInst::ICMP_SLT && match(Op1, m_ZeroInt())) ||
1195  (Pred == ICmpInst::ICMP_SGT && match(Op1, m_AllOnes()))) {
1196  // (x <s 0) ? -1 : 0 -> ashr x, 31 -> all ones if negative
1197  // (x >s -1) ? -1 : 0 -> not (ashr x, 31) -> all ones if positive
1198  Value *Sh = ConstantInt::get(Op0->getType(),
1199  Op0->getType()->getScalarSizeInBits() - 1);
1200  Value *In = Builder.CreateAShr(Op0, Sh, Op0->getName() + ".lobit");
1201  if (In->getType() != CI.getType())
1202  In = Builder.CreateIntCast(In, CI.getType(), true /*SExt*/);
1203 
1204  if (Pred == ICmpInst::ICMP_SGT)
1205  In = Builder.CreateNot(In, In->getName() + ".not");
1206  return replaceInstUsesWith(CI, In);
1207  }
1208 
1209  if (ConstantInt *Op1C = dyn_cast<ConstantInt>(Op1)) {
1210  // If we know that only one bit of the LHS of the icmp can be set and we
1211  // have an equality comparison with zero or a power of 2, we can transform
1212  // the icmp and sext into bitwise/integer operations.
1213  if (ICI->hasOneUse() &&
1214  ICI->isEquality() && (Op1C->isZero() || Op1C->getValue().isPowerOf2())){
1215  KnownBits Known = computeKnownBits(Op0, 0, &CI);
1216 
1217  APInt KnownZeroMask(~Known.Zero);
1218  if (KnownZeroMask.isPowerOf2()) {
1219  Value *In = ICI->getOperand(0);
1220 
1221  // If the icmp tests for a known zero bit we can constant fold it.
1222  if (!Op1C->isZero() && Op1C->getValue() != KnownZeroMask) {
1223  Value *V = Pred == ICmpInst::ICMP_NE ?
1226  return replaceInstUsesWith(CI, V);
1227  }
1228 
1229  if (!Op1C->isZero() == (Pred == ICmpInst::ICMP_NE)) {
1230  // sext ((x & 2^n) == 0) -> (x >> n) - 1
1231  // sext ((x & 2^n) != 2^n) -> (x >> n) - 1
1232  unsigned ShiftAmt = KnownZeroMask.countTrailingZeros();
1233  // Perform a right shift to place the desired bit in the LSB.
1234  if (ShiftAmt)
1235  In = Builder.CreateLShr(In,
1236  ConstantInt::get(In->getType(), ShiftAmt));
1237 
1238  // At this point "In" is either 1 or 0. Subtract 1 to turn
1239  // {1, 0} -> {0, -1}.
1240  In = Builder.CreateAdd(In,
1242  "sext");
1243  } else {
1244  // sext ((x & 2^n) != 0) -> (x << bitwidth-n) a>> bitwidth-1
1245  // sext ((x & 2^n) == 2^n) -> (x << bitwidth-n) a>> bitwidth-1
1246  unsigned ShiftAmt = KnownZeroMask.countLeadingZeros();
1247  // Perform a left shift to place the desired bit in the MSB.
1248  if (ShiftAmt)
1249  In = Builder.CreateShl(In,
1250  ConstantInt::get(In->getType(), ShiftAmt));
1251 
1252  // Distribute the bit over the whole bit width.
1253  In = Builder.CreateAShr(In, ConstantInt::get(In->getType(),
1254  KnownZeroMask.getBitWidth() - 1), "sext");
1255  }
1256 
1257  if (CI.getType() == In->getType())
1258  return replaceInstUsesWith(CI, In);
1259  return CastInst::CreateIntegerCast(In, CI.getType(), true/*SExt*/);
1260  }
1261  }
1262  }
1263 
1264  return nullptr;
1265 }
1266 
1267 /// Return true if we can take the specified value and return it as type Ty
1268 /// without inserting any new casts and without changing the value of the common
1269 /// low bits. This is used by code that tries to promote integer operations to
1270 /// a wider types will allow us to eliminate the extension.
1271 ///
1272 /// This function works on both vectors and scalars.
1273 ///
1274 static bool canEvaluateSExtd(Value *V, Type *Ty) {
1276  "Can't sign extend type to a smaller type");
1277  if (canAlwaysEvaluateInType(V, Ty))
1278  return true;
1279  if (canNotEvaluateInType(V, Ty))
1280  return false;
1281 
1282  auto *I = cast<Instruction>(V);
1283  switch (I->getOpcode()) {
1284  case Instruction::SExt: // sext(sext(x)) -> sext(x)
1285  case Instruction::ZExt: // sext(zext(x)) -> zext(x)
1286  case Instruction::Trunc: // sext(trunc(x)) -> trunc(x) or sext(x)
1287  return true;
1288  case Instruction::And:
1289  case Instruction::Or:
1290  case Instruction::Xor:
1291  case Instruction::Add:
1292  case Instruction::Sub:
1293  case Instruction::Mul:
1294  // These operators can all arbitrarily be extended if their inputs can.
1295  return canEvaluateSExtd(I->getOperand(0), Ty) &&
1296  canEvaluateSExtd(I->getOperand(1), Ty);
1297 
1298  //case Instruction::Shl: TODO
1299  //case Instruction::LShr: TODO
1300 
1301  case Instruction::Select:
1302  return canEvaluateSExtd(I->getOperand(1), Ty) &&
1303  canEvaluateSExtd(I->getOperand(2), Ty);
1304 
1305  case Instruction::PHI: {
1306  // We can change a phi if we can change all operands. Note that we never
1307  // get into trouble with cyclic PHIs here because we only consider
1308  // instructions with a single use.
1309  PHINode *PN = cast<PHINode>(I);
1310  for (Value *IncValue : PN->incoming_values())
1311  if (!canEvaluateSExtd(IncValue, Ty)) return false;
1312  return true;
1313  }
1314  default:
1315  // TODO: Can handle more cases here.
1316  break;
1317  }
1318 
1319  return false;
1320 }
1321 
1323  // If this sign extend is only used by a truncate, let the truncate be
1324  // eliminated before we try to optimize this sext.
1325  if (CI.hasOneUse() && isa<TruncInst>(CI.user_back()))
1326  return nullptr;
1327 
1328  if (Instruction *I = commonCastTransforms(CI))
1329  return I;
1330 
1331  Value *Src = CI.getOperand(0);
1332  Type *SrcTy = Src->getType(), *DestTy = CI.getType();
1333 
1334  // If we know that the value being extended is positive, we can use a zext
1335  // instead.
1336  KnownBits Known = computeKnownBits(Src, 0, &CI);
1337  if (Known.isNonNegative()) {
1338  Value *ZExt = Builder.CreateZExt(Src, DestTy);
1339  return replaceInstUsesWith(CI, ZExt);
1340  }
1341 
1342  // Attempt to extend the entire input expression tree to the destination
1343  // type. Only do this if the dest type is a simple type, don't convert the
1344  // expression tree to something weird like i93 unless the source is also
1345  // strange.
1346  if ((DestTy->isVectorTy() || shouldChangeType(SrcTy, DestTy)) &&
1347  canEvaluateSExtd(Src, DestTy)) {
1348  // Okay, we can transform this! Insert the new expression now.
1349  LLVM_DEBUG(
1350  dbgs() << "ICE: EvaluateInDifferentType converting expression type"
1351  " to avoid sign extend: "
1352  << CI << '\n');
1353  Value *Res = EvaluateInDifferentType(Src, DestTy, true);
1354  assert(Res->getType() == DestTy);
1355 
1356  uint32_t SrcBitSize = SrcTy->getScalarSizeInBits();
1357  uint32_t DestBitSize = DestTy->getScalarSizeInBits();
1358 
1359  // If the high bits are already filled with sign bit, just replace this
1360  // cast with the result.
1361  if (ComputeNumSignBits(Res, 0, &CI) > DestBitSize - SrcBitSize)
1362  return replaceInstUsesWith(CI, Res);
1363 
1364  // We need to emit a shl + ashr to do the sign extend.
1365  Value *ShAmt = ConstantInt::get(DestTy, DestBitSize-SrcBitSize);
1366  return BinaryOperator::CreateAShr(Builder.CreateShl(Res, ShAmt, "sext"),
1367  ShAmt);
1368  }
1369 
1370  // If the input is a trunc from the destination type, then turn sext(trunc(x))
1371  // into shifts.
1372  Value *X;
1373  if (match(Src, m_OneUse(m_Trunc(m_Value(X)))) && X->getType() == DestTy) {
1374  // sext(trunc(X)) --> ashr(shl(X, C), C)
1375  unsigned SrcBitSize = SrcTy->getScalarSizeInBits();
1376  unsigned DestBitSize = DestTy->getScalarSizeInBits();
1377  Constant *ShAmt = ConstantInt::get(DestTy, DestBitSize - SrcBitSize);
1378  return BinaryOperator::CreateAShr(Builder.CreateShl(X, ShAmt), ShAmt);
1379  }
1380 
1381  if (ICmpInst *ICI = dyn_cast<ICmpInst>(Src))
1382  return transformSExtICmp(ICI, CI);
1383 
1384  // If the input is a shl/ashr pair of a same constant, then this is a sign
1385  // extension from a smaller value. If we could trust arbitrary bitwidth
1386  // integers, we could turn this into a truncate to the smaller bit and then
1387  // use a sext for the whole extension. Since we don't, look deeper and check
1388  // for a truncate. If the source and dest are the same type, eliminate the
1389  // trunc and extend and just do shifts. For example, turn:
1390  // %a = trunc i32 %i to i8
1391  // %b = shl i8 %a, 6
1392  // %c = ashr i8 %b, 6
1393  // %d = sext i8 %c to i32
1394  // into:
1395  // %a = shl i32 %i, 30
1396  // %d = ashr i32 %a, 30
1397  Value *A = nullptr;
1398  // TODO: Eventually this could be subsumed by EvaluateInDifferentType.
1399  ConstantInt *BA = nullptr, *CA = nullptr;
1400  if (match(Src, m_AShr(m_Shl(m_Trunc(m_Value(A)), m_ConstantInt(BA)),
1401  m_ConstantInt(CA))) &&
1402  BA == CA && A->getType() == CI.getType()) {
1403  unsigned MidSize = Src->getType()->getScalarSizeInBits();
1404  unsigned SrcDstSize = CI.getType()->getScalarSizeInBits();
1405  unsigned ShAmt = CA->getZExtValue()+SrcDstSize-MidSize;
1406  Constant *ShAmtV = ConstantInt::get(CI.getType(), ShAmt);
1407  A = Builder.CreateShl(A, ShAmtV, CI.getName());
1408  return BinaryOperator::CreateAShr(A, ShAmtV);
1409  }
1410 
1411  return nullptr;
1412 }
1413 
1414 
1415 /// Return a Constant* for the specified floating-point constant if it fits
1416 /// in the specified FP type without changing its value.
1417 static bool fitsInFPType(ConstantFP *CFP, const fltSemantics &Sem) {
1418  bool losesInfo;
1419  APFloat F = CFP->getValueAPF();
1420  (void)F.convert(Sem, APFloat::rmNearestTiesToEven, &losesInfo);
1421  return !losesInfo;
1422 }
1423 
1425  if (CFP->getType() == Type::getPPC_FP128Ty(CFP->getContext()))
1426  return nullptr; // No constant folding of this.
1427  // See if the value can be truncated to half and then reextended.
1428  if (fitsInFPType(CFP, APFloat::IEEEhalf()))
1429  return Type::getHalfTy(CFP->getContext());
1430  // See if the value can be truncated to float and then reextended.
1431  if (fitsInFPType(CFP, APFloat::IEEEsingle()))
1432  return Type::getFloatTy(CFP->getContext());
1433  if (CFP->getType()->isDoubleTy())
1434  return nullptr; // Won't shrink.
1435  if (fitsInFPType(CFP, APFloat::IEEEdouble()))
1436  return Type::getDoubleTy(CFP->getContext());
1437  // Don't try to shrink to various long double types.
1438  return nullptr;
1439 }
1440 
1441 // Determine if this is a vector of ConstantFPs and if so, return the minimal
1442 // type we can safely truncate all elements to.
1443 // TODO: Make these support undef elements.
1445  auto *CV = dyn_cast<Constant>(V);
1446  if (!CV || !CV->getType()->isVectorTy())
1447  return nullptr;
1448 
1449  Type *MinType = nullptr;
1450 
1451  unsigned NumElts = CV->getType()->getVectorNumElements();
1452  for (unsigned i = 0; i != NumElts; ++i) {
1453  auto *CFP = dyn_cast_or_null<ConstantFP>(CV->getAggregateElement(i));
1454  if (!CFP)
1455  return nullptr;
1456 
1457  Type *T = shrinkFPConstant(CFP);
1458  if (!T)
1459  return nullptr;
1460 
1461  // If we haven't found a type yet or this type has a larger mantissa than
1462  // our previous type, this is our new minimal type.
1463  if (!MinType || T->getFPMantissaWidth() > MinType->getFPMantissaWidth())
1464  MinType = T;
1465  }
1466 
1467  // Make a vector type from the minimal type.
1468  return VectorType::get(MinType, NumElts);
1469 }
1470 
1471 /// Find the minimum FP type we can safely truncate to.
1473  if (auto *FPExt = dyn_cast<FPExtInst>(V))
1474  return FPExt->getOperand(0)->getType();
1475 
1476  // If this value is a constant, return the constant in the smallest FP type
1477  // that can accurately represent it. This allows us to turn
1478  // (float)((double)X+2.0) into x+2.0f.
1479  if (auto *CFP = dyn_cast<ConstantFP>(V))
1480  if (Type *T = shrinkFPConstant(CFP))
1481  return T;
1482 
1483  // Try to shrink a vector of FP constants.
1484  if (Type *T = shrinkFPConstantVector(V))
1485  return T;
1486 
1487  return V->getType();
1488 }
1489 
1491  if (Instruction *I = commonCastTransforms(FPT))
1492  return I;
1493 
1494  // If we have fptrunc(OpI (fpextend x), (fpextend y)), we would like to
1495  // simplify this expression to avoid one or more of the trunc/extend
1496  // operations if we can do so without changing the numerical results.
1497  //
1498  // The exact manner in which the widths of the operands interact to limit
1499  // what we can and cannot do safely varies from operation to operation, and
1500  // is explained below in the various case statements.
1501  Type *Ty = FPT.getType();
1503  if (OpI && OpI->hasOneUse()) {
1504  Type *LHSMinType = getMinimumFPType(OpI->getOperand(0));
1505  Type *RHSMinType = getMinimumFPType(OpI->getOperand(1));
1506  unsigned OpWidth = OpI->getType()->getFPMantissaWidth();
1507  unsigned LHSWidth = LHSMinType->getFPMantissaWidth();
1508  unsigned RHSWidth = RHSMinType->getFPMantissaWidth();
1509  unsigned SrcWidth = std::max(LHSWidth, RHSWidth);
1510  unsigned DstWidth = Ty->getFPMantissaWidth();
1511  switch (OpI->getOpcode()) {
1512  default: break;
1513  case Instruction::FAdd:
1514  case Instruction::FSub:
1515  // For addition and subtraction, the infinitely precise result can
1516  // essentially be arbitrarily wide; proving that double rounding
1517  // will not occur because the result of OpI is exact (as we will for
1518  // FMul, for example) is hopeless. However, we *can* nonetheless
1519  // frequently know that double rounding cannot occur (or that it is
1520  // innocuous) by taking advantage of the specific structure of
1521  // infinitely-precise results that admit double rounding.
1522  //
1523  // Specifically, if OpWidth >= 2*DstWdith+1 and DstWidth is sufficient
1524  // to represent both sources, we can guarantee that the double
1525  // rounding is innocuous (See p50 of Figueroa's 2000 PhD thesis,
1526  // "A Rigorous Framework for Fully Supporting the IEEE Standard ..."
1527  // for proof of this fact).
1528  //
1529  // Note: Figueroa does not consider the case where DstFormat !=
1530  // SrcFormat. It's possible (likely even!) that this analysis
1531  // could be tightened for those cases, but they are rare (the main
1532  // case of interest here is (float)((double)float + float)).
1533  if (OpWidth >= 2*DstWidth+1 && DstWidth >= SrcWidth) {
1534  Value *LHS = Builder.CreateFPTrunc(OpI->getOperand(0), Ty);
1535  Value *RHS = Builder.CreateFPTrunc(OpI->getOperand(1), Ty);
1536  Instruction *RI = BinaryOperator::Create(OpI->getOpcode(), LHS, RHS);
1537  RI->copyFastMathFlags(OpI);
1538  return RI;
1539  }
1540  break;
1541  case Instruction::FMul:
1542  // For multiplication, the infinitely precise result has at most
1543  // LHSWidth + RHSWidth significant bits; if OpWidth is sufficient
1544  // that such a value can be exactly represented, then no double
1545  // rounding can possibly occur; we can safely perform the operation
1546  // in the destination format if it can represent both sources.
1547  if (OpWidth >= LHSWidth + RHSWidth && DstWidth >= SrcWidth) {
1548  Value *LHS = Builder.CreateFPTrunc(OpI->getOperand(0), Ty);
1549  Value *RHS = Builder.CreateFPTrunc(OpI->getOperand(1), Ty);
1550  return BinaryOperator::CreateFMulFMF(LHS, RHS, OpI);
1551  }
1552  break;
1553  case Instruction::FDiv:
1554  // For division, we use again use the bound from Figueroa's
1555  // dissertation. I am entirely certain that this bound can be
1556  // tightened in the unbalanced operand case by an analysis based on
1557  // the diophantine rational approximation bound, but the well-known
1558  // condition used here is a good conservative first pass.
1559  // TODO: Tighten bound via rigorous analysis of the unbalanced case.
1560  if (OpWidth >= 2*DstWidth && DstWidth >= SrcWidth) {
1561  Value *LHS = Builder.CreateFPTrunc(OpI->getOperand(0), Ty);
1562  Value *RHS = Builder.CreateFPTrunc(OpI->getOperand(1), Ty);
1563  return BinaryOperator::CreateFDivFMF(LHS, RHS, OpI);
1564  }
1565  break;
1566  case Instruction::FRem: {
1567  // Remainder is straightforward. Remainder is always exact, so the
1568  // type of OpI doesn't enter into things at all. We simply evaluate
1569  // in whichever source type is larger, then convert to the
1570  // destination type.
1571  if (SrcWidth == OpWidth)
1572  break;
1573  Value *LHS, *RHS;
1574  if (LHSWidth == SrcWidth) {
1575  LHS = Builder.CreateFPTrunc(OpI->getOperand(0), LHSMinType);
1576  RHS = Builder.CreateFPTrunc(OpI->getOperand(1), LHSMinType);
1577  } else {
1578  LHS = Builder.CreateFPTrunc(OpI->getOperand(0), RHSMinType);
1579  RHS = Builder.CreateFPTrunc(OpI->getOperand(1), RHSMinType);
1580  }
1581 
1582  Value *ExactResult = Builder.CreateFRemFMF(LHS, RHS, OpI);
1583  return CastInst::CreateFPCast(ExactResult, Ty);
1584  }
1585  }
1586 
1587  // (fptrunc (fneg x)) -> (fneg (fptrunc x))
1588  if (BinaryOperator::isFNeg(OpI)) {
1589  Value *InnerTrunc = Builder.CreateFPTrunc(OpI->getOperand(1), Ty);
1590  return BinaryOperator::CreateFNegFMF(InnerTrunc, OpI);
1591  }
1592  }
1593 
1594  if (auto *II = dyn_cast<IntrinsicInst>(FPT.getOperand(0))) {
1595  switch (II->getIntrinsicID()) {
1596  default: break;
1597  case Intrinsic::ceil:
1598  case Intrinsic::fabs:
1599  case Intrinsic::floor:
1600  case Intrinsic::nearbyint:
1601  case Intrinsic::rint:
1602  case Intrinsic::round:
1603  case Intrinsic::trunc: {
1604  Value *Src = II->getArgOperand(0);
1605  if (!Src->hasOneUse())
1606  break;
1607 
1608  // Except for fabs, this transformation requires the input of the unary FP
1609  // operation to be itself an fpext from the type to which we're
1610  // truncating.
1611  if (II->getIntrinsicID() != Intrinsic::fabs) {
1612  FPExtInst *FPExtSrc = dyn_cast<FPExtInst>(Src);
1613  if (!FPExtSrc || FPExtSrc->getSrcTy() != Ty)
1614  break;
1615  }
1616 
1617  // Do unary FP operation on smaller type.
1618  // (fptrunc (fabs x)) -> (fabs (fptrunc x))
1619  Value *InnerTrunc = Builder.CreateFPTrunc(Src, Ty);
1620  Function *Overload = Intrinsic::getDeclaration(FPT.getModule(),
1621  II->getIntrinsicID(), Ty);
1623  II->getOperandBundlesAsDefs(OpBundles);
1624  CallInst *NewCI = CallInst::Create(Overload, { InnerTrunc }, OpBundles,
1625  II->getName());
1626  NewCI->copyFastMathFlags(II);
1627  return NewCI;
1628  }
1629  }
1630  }
1631 
1632  if (Instruction *I = shrinkInsertElt(FPT, Builder))
1633  return I;
1634 
1635  return nullptr;
1636 }
1637 
1639  return commonCastTransforms(CI);
1640 }
1641 
1642 // fpto{s/u}i({u/s}itofp(X)) --> X or zext(X) or sext(X) or trunc(X)
1643 // This is safe if the intermediate type has enough bits in its mantissa to
1644 // accurately represent all values of X. For example, this won't work with
1645 // i64 -> float -> i64.
1647  if (!isa<UIToFPInst>(FI.getOperand(0)) && !isa<SIToFPInst>(FI.getOperand(0)))
1648  return nullptr;
1649  Instruction *OpI = cast<Instruction>(FI.getOperand(0));
1650 
1651  Value *SrcI = OpI->getOperand(0);
1652  Type *FITy = FI.getType();
1653  Type *OpITy = OpI->getType();
1654  Type *SrcTy = SrcI->getType();
1655  bool IsInputSigned = isa<SIToFPInst>(OpI);
1656  bool IsOutputSigned = isa<FPToSIInst>(FI);
1657 
1658  // We can safely assume the conversion won't overflow the output range,
1659  // because (for example) (uint8_t)18293.f is undefined behavior.
1660 
1661  // Since we can assume the conversion won't overflow, our decision as to
1662  // whether the input will fit in the float should depend on the minimum
1663  // of the input range and output range.
1664 
1665  // This means this is also safe for a signed input and unsigned output, since
1666  // a negative input would lead to undefined behavior.
1667  int InputSize = (int)SrcTy->getScalarSizeInBits() - IsInputSigned;
1668  int OutputSize = (int)FITy->getScalarSizeInBits() - IsOutputSigned;
1669  int ActualSize = std::min(InputSize, OutputSize);
1670 
1671  if (ActualSize <= OpITy->getFPMantissaWidth()) {
1672  if (FITy->getScalarSizeInBits() > SrcTy->getScalarSizeInBits()) {
1673  if (IsInputSigned && IsOutputSigned)
1674  return new SExtInst(SrcI, FITy);
1675  return new ZExtInst(SrcI, FITy);
1676  }
1677  if (FITy->getScalarSizeInBits() < SrcTy->getScalarSizeInBits())
1678  return new TruncInst(SrcI, FITy);
1679  if (SrcTy == FITy)
1680  return replaceInstUsesWith(FI, SrcI);
1681  return new BitCastInst(SrcI, FITy);
1682  }
1683  return nullptr;
1684 }
1685 
1687  Instruction *OpI = dyn_cast<Instruction>(FI.getOperand(0));
1688  if (!OpI)
1689  return commonCastTransforms(FI);
1690 
1691  if (Instruction *I = FoldItoFPtoI(FI))
1692  return I;
1693 
1694  return commonCastTransforms(FI);
1695 }
1696 
1698  Instruction *OpI = dyn_cast<Instruction>(FI.getOperand(0));
1699  if (!OpI)
1700  return commonCastTransforms(FI);
1701 
1702  if (Instruction *I = FoldItoFPtoI(FI))
1703  return I;
1704 
1705  return commonCastTransforms(FI);
1706 }
1707 
1709  return commonCastTransforms(CI);
1710 }
1711 
1713  return commonCastTransforms(CI);
1714 }
1715 
1717  // If the source integer type is not the intptr_t type for this target, do a
1718  // trunc or zext to the intptr_t type, then inttoptr of it. This allows the
1719  // cast to be exposed to other transforms.
1720  unsigned AS = CI.getAddressSpace();
1721  if (CI.getOperand(0)->getType()->getScalarSizeInBits() !=
1722  DL.getPointerSizeInBits(AS)) {
1723  Type *Ty = DL.getIntPtrType(CI.getContext(), AS);
1724  if (CI.getType()->isVectorTy()) // Handle vectors of pointers.
1725  Ty = VectorType::get(Ty, CI.getType()->getVectorNumElements());
1726 
1727  Value *P = Builder.CreateZExtOrTrunc(CI.getOperand(0), Ty);
1728  return new IntToPtrInst(P, CI.getType());
1729  }
1730 
1731  if (Instruction *I = commonCastTransforms(CI))
1732  return I;
1733 
1734  return nullptr;
1735 }
1736 
1737 /// Implement the transforms for cast of pointer (bitcast/ptrtoint)
1739  Value *Src = CI.getOperand(0);
1740 
1741  if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Src)) {
1742  // If casting the result of a getelementptr instruction with no offset, turn
1743  // this into a cast of the original pointer!
1744  if (GEP->hasAllZeroIndices() &&
1745  // If CI is an addrspacecast and GEP changes the poiner type, merging
1746  // GEP into CI would undo canonicalizing addrspacecast with different
1747  // pointer types, causing infinite loops.
1748  (!isa<AddrSpaceCastInst>(CI) ||
1749  GEP->getType() == GEP->getPointerOperandType())) {
1750  // Changing the cast operand is usually not a good idea but it is safe
1751  // here because the pointer operand is being replaced with another
1752  // pointer operand so the opcode doesn't need to change.
1753  Worklist.Add(GEP);
1754  CI.setOperand(0, GEP->getOperand(0));
1755  return &CI;
1756  }
1757  }
1758 
1759  return commonCastTransforms(CI);
1760 }
1761 
1763  // If the destination integer type is not the intptr_t type for this target,
1764  // do a ptrtoint to intptr_t then do a trunc or zext. This allows the cast
1765  // to be exposed to other transforms.
1766 
1767  Type *Ty = CI.getType();
1768  unsigned AS = CI.getPointerAddressSpace();
1769 
1770  if (Ty->getScalarSizeInBits() == DL.getIndexSizeInBits(AS))
1771  return commonPointerCastTransforms(CI);
1772 
1773  Type *PtrTy = DL.getIntPtrType(CI.getContext(), AS);
1774  if (Ty->isVectorTy()) // Handle vectors of pointers.
1775  PtrTy = VectorType::get(PtrTy, Ty->getVectorNumElements());
1776 
1777  Value *P = Builder.CreatePtrToInt(CI.getOperand(0), PtrTy);
1778  return CastInst::CreateIntegerCast(P, Ty, /*isSigned=*/false);
1779 }
1780 
1781 /// This input value (which is known to have vector type) is being zero extended
1782 /// or truncated to the specified vector type.
1783 /// Try to replace it with a shuffle (and vector/vector bitcast) if possible.
1784 ///
1785 /// The source and destination vector types may have different element types.
1787  InstCombiner &IC) {
1788  // We can only do this optimization if the output is a multiple of the input
1789  // element size, or the input is a multiple of the output element size.
1790  // Convert the input type to have the same element type as the output.
1791  VectorType *SrcTy = cast<VectorType>(InVal->getType());
1792 
1793  if (SrcTy->getElementType() != DestTy->getElementType()) {
1794  // The input types don't need to be identical, but for now they must be the
1795  // same size. There is no specific reason we couldn't handle things like
1796  // <4 x i16> -> <4 x i32> by bitcasting to <2 x i32> but haven't gotten
1797  // there yet.
1798  if (SrcTy->getElementType()->getPrimitiveSizeInBits() !=
1800  return nullptr;
1801 
1802  SrcTy = VectorType::get(DestTy->getElementType(), SrcTy->getNumElements());
1803  InVal = IC.Builder.CreateBitCast(InVal, SrcTy);
1804  }
1805 
1806  // Now that the element types match, get the shuffle mask and RHS of the
1807  // shuffle to use, which depends on whether we're increasing or decreasing the
1808  // size of the input.
1809  SmallVector<uint32_t, 16> ShuffleMask;
1810  Value *V2;
1811 
1812  if (SrcTy->getNumElements() > DestTy->getNumElements()) {
1813  // If we're shrinking the number of elements, just shuffle in the low
1814  // elements from the input and use undef as the second shuffle input.
1815  V2 = UndefValue::get(SrcTy);
1816  for (unsigned i = 0, e = DestTy->getNumElements(); i != e; ++i)
1817  ShuffleMask.push_back(i);
1818 
1819  } else {
1820  // If we're increasing the number of elements, shuffle in all of the
1821  // elements from InVal and fill the rest of the result elements with zeros
1822  // from a constant zero.
1823  V2 = Constant::getNullValue(SrcTy);
1824  unsigned SrcElts = SrcTy->getNumElements();
1825  for (unsigned i = 0, e = SrcElts; i != e; ++i)
1826  ShuffleMask.push_back(i);
1827 
1828  // The excess elements reference the first element of the zero input.
1829  for (unsigned i = 0, e = DestTy->getNumElements()-SrcElts; i != e; ++i)
1830  ShuffleMask.push_back(SrcElts);
1831  }
1832 
1833  return new ShuffleVectorInst(InVal, V2,
1835  ShuffleMask));
1836 }
1837 
1838 static bool isMultipleOfTypeSize(unsigned Value, Type *Ty) {
1839  return Value % Ty->getPrimitiveSizeInBits() == 0;
1840 }
1841 
1842 static unsigned getTypeSizeIndex(unsigned Value, Type *Ty) {
1843  return Value / Ty->getPrimitiveSizeInBits();
1844 }
1845 
1846 /// V is a value which is inserted into a vector of VecEltTy.
1847 /// Look through the value to see if we can decompose it into
1848 /// insertions into the vector. See the example in the comment for
1849 /// OptimizeIntegerToVectorInsertions for the pattern this handles.
1850 /// The type of V is always a non-zero multiple of VecEltTy's size.
1851 /// Shift is the number of bits between the lsb of V and the lsb of
1852 /// the vector.
1853 ///
1854 /// This returns false if the pattern can't be matched or true if it can,
1855 /// filling in Elements with the elements found here.
1856 static bool collectInsertionElements(Value *V, unsigned Shift,
1857  SmallVectorImpl<Value *> &Elements,
1858  Type *VecEltTy, bool isBigEndian) {
1859  assert(isMultipleOfTypeSize(Shift, VecEltTy) &&
1860  "Shift should be a multiple of the element type size");
1861 
1862  // Undef values never contribute useful bits to the result.
1863  if (isa<UndefValue>(V)) return true;
1864 
1865  // If we got down to a value of the right type, we win, try inserting into the
1866  // right element.
1867  if (V->getType() == VecEltTy) {
1868  // Inserting null doesn't actually insert any elements.
1869  if (Constant *C = dyn_cast<Constant>(V))
1870  if (C->isNullValue())
1871  return true;
1872 
1873  unsigned ElementIndex = getTypeSizeIndex(Shift, VecEltTy);
1874  if (isBigEndian)
1875  ElementIndex = Elements.size() - ElementIndex - 1;
1876 
1877  // Fail if multiple elements are inserted into this slot.
1878  if (Elements[ElementIndex])
1879  return false;
1880 
1881  Elements[ElementIndex] = V;
1882  return true;
1883  }
1884 
1885  if (Constant *C = dyn_cast<Constant>(V)) {
1886  // Figure out the # elements this provides, and bitcast it or slice it up
1887  // as required.
1888  unsigned NumElts = getTypeSizeIndex(C->getType()->getPrimitiveSizeInBits(),
1889  VecEltTy);
1890  // If the constant is the size of a vector element, we just need to bitcast
1891  // it to the right type so it gets properly inserted.
1892  if (NumElts == 1)
1894  Shift, Elements, VecEltTy, isBigEndian);
1895 
1896  // Okay, this is a constant that covers multiple elements. Slice it up into
1897  // pieces and insert each element-sized piece into the vector.
1898  if (!isa<IntegerType>(C->getType()))
1901  unsigned ElementSize = VecEltTy->getPrimitiveSizeInBits();
1902  Type *ElementIntTy = IntegerType::get(C->getContext(), ElementSize);
1903 
1904  for (unsigned i = 0; i != NumElts; ++i) {
1905  unsigned ShiftI = Shift+i*ElementSize;
1907  ShiftI));
1908  Piece = ConstantExpr::getTrunc(Piece, ElementIntTy);
1909  if (!collectInsertionElements(Piece, ShiftI, Elements, VecEltTy,
1910  isBigEndian))
1911  return false;
1912  }
1913  return true;
1914  }
1915 
1916  if (!V->hasOneUse()) return false;
1917 
1919  if (!I) return false;
1920  switch (I->getOpcode()) {
1921  default: return false; // Unhandled case.
1922  case Instruction::BitCast:
1923  return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
1924  isBigEndian);
1925  case Instruction::ZExt:
1926  if (!isMultipleOfTypeSize(
1928  VecEltTy))
1929  return false;
1930  return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
1931  isBigEndian);
1932  case Instruction::Or:
1933  return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
1934  isBigEndian) &&
1935  collectInsertionElements(I->getOperand(1), Shift, Elements, VecEltTy,
1936  isBigEndian);
1937  case Instruction::Shl: {
1938  // Must be shifting by a constant that is a multiple of the element size.
1940  if (!CI) return false;
1941  Shift += CI->getZExtValue();
1942  if (!isMultipleOfTypeSize(Shift, VecEltTy)) return false;
1943  return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
1944  isBigEndian);
1945  }
1946 
1947  }
1948 }
1949 
1950 
1951 /// If the input is an 'or' instruction, we may be doing shifts and ors to
1952 /// assemble the elements of the vector manually.
1953 /// Try to rip the code out and replace it with insertelements. This is to
1954 /// optimize code like this:
1955 ///
1956 /// %tmp37 = bitcast float %inc to i32
1957 /// %tmp38 = zext i32 %tmp37 to i64
1958 /// %tmp31 = bitcast float %inc5 to i32
1959 /// %tmp32 = zext i32 %tmp31 to i64
1960 /// %tmp33 = shl i64 %tmp32, 32
1961 /// %ins35 = or i64 %tmp33, %tmp38
1962 /// %tmp43 = bitcast i64 %ins35 to <2 x float>
1963 ///
1964 /// Into two insertelements that do "buildvector{%inc, %inc5}".
1966  InstCombiner &IC) {
1967  VectorType *DestVecTy = cast<VectorType>(CI.getType());
1968  Value *IntInput = CI.getOperand(0);
1969 
1970  SmallVector<Value*, 8> Elements(DestVecTy->getNumElements());
1971  if (!collectInsertionElements(IntInput, 0, Elements,
1972  DestVecTy->getElementType(),
1973  IC.getDataLayout().isBigEndian()))
1974  return nullptr;
1975 
1976  // If we succeeded, we know that all of the element are specified by Elements
1977  // or are zero if Elements has a null entry. Recast this as a set of
1978  // insertions.
1979  Value *Result = Constant::getNullValue(CI.getType());
1980  for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
1981  if (!Elements[i]) continue; // Unset element.
1982 
1983  Result = IC.Builder.CreateInsertElement(Result, Elements[i],
1984  IC.Builder.getInt32(i));
1985  }
1986 
1987  return Result;
1988 }
1989 
1990 /// Canonicalize scalar bitcasts of extracted elements into a bitcast of the
1991 /// vector followed by extract element. The backend tends to handle bitcasts of
1992 /// vectors better than bitcasts of scalars because vector registers are
1993 /// usually not type-specific like scalar integer or scalar floating-point.
1995  InstCombiner &IC) {
1996  // TODO: Create and use a pattern matcher for ExtractElementInst.
1997  auto *ExtElt = dyn_cast<ExtractElementInst>(BitCast.getOperand(0));
1998  if (!ExtElt || !ExtElt->hasOneUse())
1999  return nullptr;
2000 
2001  // The bitcast must be to a vectorizable type, otherwise we can't make a new
2002  // type to extract from.
2003  Type *DestType = BitCast.getType();
2004  if (!VectorType::isValidElementType(DestType))
2005  return nullptr;
2006 
2007  unsigned NumElts = ExtElt->getVectorOperandType()->getNumElements();
2008  auto *NewVecType = VectorType::get(DestType, NumElts);
2009  auto *NewBC = IC.Builder.CreateBitCast(ExtElt->getVectorOperand(),
2010  NewVecType, "bc");
2011  return ExtractElementInst::Create(NewBC, ExtElt->getIndexOperand());
2012 }
2013 
2014 /// Change the type of a bitwise logic operation if we can eliminate a bitcast.
2016  InstCombiner::BuilderTy &Builder) {
2017  Type *DestTy = BitCast.getType();
2018  BinaryOperator *BO;
2019  if (!DestTy->isIntOrIntVectorTy() ||
2020  !match(BitCast.getOperand(0), m_OneUse(m_BinOp(BO))) ||
2021  !BO->isBitwiseLogicOp())
2022  return nullptr;
2023 
2024  // FIXME: This transform is restricted to vector types to avoid backend
2025  // problems caused by creating potentially illegal operations. If a fix-up is
2026  // added to handle that situation, we can remove this check.
2027  if (!DestTy->isVectorTy() || !BO->getType()->isVectorTy())
2028  return nullptr;
2029 
2030  Value *X;
2031  if (match(BO->getOperand(0), m_OneUse(m_BitCast(m_Value(X)))) &&
2032  X->getType() == DestTy && !isa<Constant>(X)) {
2033  // bitcast(logic(bitcast(X), Y)) --> logic'(X, bitcast(Y))
2034  Value *CastedOp1 = Builder.CreateBitCast(BO->getOperand(1), DestTy);
2035  return BinaryOperator::Create(BO->getOpcode(), X, CastedOp1);
2036  }
2037 
2038  if (match(BO->getOperand(1), m_OneUse(m_BitCast(m_Value(X)))) &&
2039  X->getType() == DestTy && !isa<Constant>(X)) {
2040  // bitcast(logic(Y, bitcast(X))) --> logic'(bitcast(Y), X)
2041  Value *CastedOp0 = Builder.CreateBitCast(BO->getOperand(0), DestTy);
2042  return BinaryOperator::Create(BO->getOpcode(), CastedOp0, X);
2043  }
2044 
2045  // Canonicalize vector bitcasts to come before vector bitwise logic with a
2046  // constant. This eases recognition of special constants for later ops.
2047  // Example:
2048  // icmp u/s (a ^ signmask), (b ^ signmask) --> icmp s/u a, b
2049  Constant *C;
2050  if (match(BO->getOperand(1), m_Constant(C))) {
2051  // bitcast (logic X, C) --> logic (bitcast X, C')
2052  Value *CastedOp0 = Builder.CreateBitCast(BO->getOperand(0), DestTy);
2053  Value *CastedC = ConstantExpr::getBitCast(C, DestTy);
2054  return BinaryOperator::Create(BO->getOpcode(), CastedOp0, CastedC);
2055  }
2056 
2057  return nullptr;
2058 }
2059 
2060 /// Change the type of a select if we can eliminate a bitcast.
2062  InstCombiner::BuilderTy &Builder) {
2063  Value *Cond, *TVal, *FVal;
2064  if (!match(BitCast.getOperand(0),
2065  m_OneUse(m_Select(m_Value(Cond), m_Value(TVal), m_Value(FVal)))))
2066  return nullptr;
2067 
2068  // A vector select must maintain the same number of elements in its operands.
2069  Type *CondTy = Cond->getType();
2070  Type *DestTy = BitCast.getType();
2071  if (CondTy->isVectorTy()) {
2072  if (!DestTy->isVectorTy())
2073  return nullptr;
2074  if (DestTy->getVectorNumElements() != CondTy->getVectorNumElements())
2075  return nullptr;
2076  }
2077 
2078  // FIXME: This transform is restricted from changing the select between
2079  // scalars and vectors to avoid backend problems caused by creating
2080  // potentially illegal operations. If a fix-up is added to handle that
2081  // situation, we can remove this check.
2082  if (DestTy->isVectorTy() != TVal->getType()->isVectorTy())
2083  return nullptr;
2084 
2085  auto *Sel = cast<Instruction>(BitCast.getOperand(0));
2086  Value *X;
2087  if (match(TVal, m_OneUse(m_BitCast(m_Value(X)))) && X->getType() == DestTy &&
2088  !isa<Constant>(X)) {
2089  // bitcast(select(Cond, bitcast(X), Y)) --> select'(Cond, X, bitcast(Y))
2090  Value *CastedVal = Builder.CreateBitCast(FVal, DestTy);
2091  return SelectInst::Create(Cond, X, CastedVal, "", nullptr, Sel);
2092  }
2093 
2094  if (match(FVal, m_OneUse(m_BitCast(m_Value(X)))) && X->getType() == DestTy &&
2095  !isa<Constant>(X)) {
2096  // bitcast(select(Cond, Y, bitcast(X))) --> select'(Cond, bitcast(Y), X)
2097  Value *CastedVal = Builder.CreateBitCast(TVal, DestTy);
2098  return SelectInst::Create(Cond, CastedVal, X, "", nullptr, Sel);
2099  }
2100 
2101  return nullptr;
2102 }
2103 
2104 /// Check if all users of CI are StoreInsts.
2105 static bool hasStoreUsersOnly(CastInst &CI) {
2106  for (User *U : CI.users()) {
2107  if (!isa<StoreInst>(U))
2108  return false;
2109  }
2110  return true;
2111 }
2112 
2113 /// This function handles following case
2114 ///
2115 /// A -> B cast
2116 /// PHI
2117 /// B -> A cast
2118 ///
2119 /// All the related PHI nodes can be replaced by new PHI nodes with type A.
2120 /// The uses of \p CI can be changed to the new PHI node corresponding to \p PN.
2121 Instruction *InstCombiner::optimizeBitCastFromPhi(CastInst &CI, PHINode *PN) {
2122  // BitCast used by Store can be handled in InstCombineLoadStoreAlloca.cpp.
2123  if (hasStoreUsersOnly(CI))
2124  return nullptr;
2125 
2126  Value *Src = CI.getOperand(0);
2127  Type *SrcTy = Src->getType(); // Type B
2128  Type *DestTy = CI.getType(); // Type A
2129 
2130  SmallVector<PHINode *, 4> PhiWorklist;
2131  SmallSetVector<PHINode *, 4> OldPhiNodes;
2132 
2133  // Find all of the A->B casts and PHI nodes.
2134  // We need to inpect all related PHI nodes, but PHIs can be cyclic, so
2135  // OldPhiNodes is used to track all known PHI nodes, before adding a new
2136  // PHI to PhiWorklist, it is checked against and added to OldPhiNodes first.
2137  PhiWorklist.push_back(PN);
2138  OldPhiNodes.insert(PN);
2139  while (!PhiWorklist.empty()) {
2140  auto *OldPN = PhiWorklist.pop_back_val();
2141  for (Value *IncValue : OldPN->incoming_values()) {
2142  if (isa<Constant>(IncValue))
2143  continue;
2144 
2145  if (auto *LI = dyn_cast<LoadInst>(IncValue)) {
2146  // If there is a sequence of one or more load instructions, each loaded
2147  // value is used as address of later load instruction, bitcast is
2148  // necessary to change the value type, don't optimize it. For
2149  // simplicity we give up if the load address comes from another load.
2150  Value *Addr = LI->getOperand(0);
2151  if (Addr == &CI || isa<LoadInst>(Addr))
2152  return nullptr;
2153  if (LI->hasOneUse() && LI->isSimple())
2154  continue;
2155  // If a LoadInst has more than one use, changing the type of loaded
2156  // value may create another bitcast.
2157  return nullptr;
2158  }
2159 
2160  if (auto *PNode = dyn_cast<PHINode>(IncValue)) {
2161  if (OldPhiNodes.insert(PNode))
2162  PhiWorklist.push_back(PNode);
2163  continue;
2164  }
2165 
2166  auto *BCI = dyn_cast<BitCastInst>(IncValue);
2167  // We can't handle other instructions.
2168  if (!BCI)
2169  return nullptr;
2170 
2171  // Verify it's a A->B cast.
2172  Type *TyA = BCI->getOperand(0)->getType();
2173  Type *TyB = BCI->getType();
2174  if (TyA != DestTy || TyB != SrcTy)
2175  return nullptr;
2176  }
2177  }
2178 
2179  // For each old PHI node, create a corresponding new PHI node with a type A.
2181  for (auto *OldPN : OldPhiNodes) {
2182  Builder.SetInsertPoint(OldPN);
2183  PHINode *NewPN = Builder.CreatePHI(DestTy, OldPN->getNumOperands());
2184  NewPNodes[OldPN] = NewPN;
2185  }
2186 
2187  // Fill in the operands of new PHI nodes.
2188  for (auto *OldPN : OldPhiNodes) {
2189  PHINode *NewPN = NewPNodes[OldPN];
2190  for (unsigned j = 0, e = OldPN->getNumOperands(); j != e; ++j) {
2191  Value *V = OldPN->getOperand(j);
2192  Value *NewV = nullptr;
2193  if (auto *C = dyn_cast<Constant>(V)) {
2194  NewV = ConstantExpr::getBitCast(C, DestTy);
2195  } else if (auto *LI = dyn_cast<LoadInst>(V)) {
2196  Builder.SetInsertPoint(LI->getNextNode());
2197  NewV = Builder.CreateBitCast(LI, DestTy);
2198  Worklist.Add(LI);
2199  } else if (auto *BCI = dyn_cast<BitCastInst>(V)) {
2200  NewV = BCI->getOperand(0);
2201  } else if (auto *PrevPN = dyn_cast<PHINode>(V)) {
2202  NewV = NewPNodes[PrevPN];
2203  }
2204  assert(NewV);
2205  NewPN->addIncoming(NewV, OldPN->getIncomingBlock(j));
2206  }
2207  }
2208 
2209  // If there is a store with type B, change it to type A.
2210  for (User *U : PN->users()) {
2211  auto *SI = dyn_cast<StoreInst>(U);
2212  if (SI && SI->isSimple() && SI->getOperand(0) == PN) {
2213  Builder.SetInsertPoint(SI);
2214  auto *NewBC =
2215  cast<BitCastInst>(Builder.CreateBitCast(NewPNodes[PN], SrcTy));
2216  SI->setOperand(0, NewBC);
2217  Worklist.Add(SI);
2218  assert(hasStoreUsersOnly(*NewBC));
2219  }
2220  }
2221 
2222  return replaceInstUsesWith(CI, NewPNodes[PN]);
2223 }
2224 
2226  // If the operands are integer typed then apply the integer transforms,
2227  // otherwise just apply the common ones.
2228  Value *Src = CI.getOperand(0);
2229  Type *SrcTy = Src->getType();
2230  Type *DestTy = CI.getType();
2231 
2232  // Get rid of casts from one type to the same type. These are useless and can
2233  // be replaced by the operand.
2234  if (DestTy == Src->getType())
2235  return replaceInstUsesWith(CI, Src);
2236 
2237  if (PointerType *DstPTy = dyn_cast<PointerType>(DestTy)) {
2238  PointerType *SrcPTy = cast<PointerType>(SrcTy);
2239  Type *DstElTy = DstPTy->getElementType();
2240  Type *SrcElTy = SrcPTy->getElementType();
2241 
2242  // If we are casting a alloca to a pointer to a type of the same
2243  // size, rewrite the allocation instruction to allocate the "right" type.
2244  // There is no need to modify malloc calls because it is their bitcast that
2245  // needs to be cleaned up.
2246  if (AllocaInst *AI = dyn_cast<AllocaInst>(Src))
2247  if (Instruction *V = PromoteCastOfAllocation(CI, *AI))
2248  return V;
2249 
2250  // When the type pointed to is not sized the cast cannot be
2251  // turned into a gep.
2252  Type *PointeeType =
2253  cast<PointerType>(Src->getType()->getScalarType())->getElementType();
2254  if (!PointeeType->isSized())
2255  return nullptr;
2256 
2257  // If the source and destination are pointers, and this cast is equivalent
2258  // to a getelementptr X, 0, 0, 0... turn it into the appropriate gep.
2259  // This can enhance SROA and other transforms that want type-safe pointers.
2260  unsigned NumZeros = 0;
2261  while (SrcElTy != DstElTy &&
2262  isa<CompositeType>(SrcElTy) && !SrcElTy->isPointerTy() &&
2263  SrcElTy->getNumContainedTypes() /* not "{}" */) {
2264  SrcElTy = cast<CompositeType>(SrcElTy)->getTypeAtIndex(0U);
2265  ++NumZeros;
2266  }
2267 
2268  // If we found a path from the src to dest, create the getelementptr now.
2269  if (SrcElTy == DstElTy) {
2270  SmallVector<Value *, 8> Idxs(NumZeros + 1, Builder.getInt32(0));
2271  return GetElementPtrInst::CreateInBounds(Src, Idxs);
2272  }
2273  }
2274 
2275  if (VectorType *DestVTy = dyn_cast<VectorType>(DestTy)) {
2276  if (DestVTy->getNumElements() == 1 && !SrcTy->isVectorTy()) {
2277  Value *Elem = Builder.CreateBitCast(Src, DestVTy->getElementType());
2278  return InsertElementInst::Create(UndefValue::get(DestTy), Elem,
2280  // FIXME: Canonicalize bitcast(insertelement) -> insertelement(bitcast)
2281  }
2282 
2283  if (isa<IntegerType>(SrcTy)) {
2284  // If this is a cast from an integer to vector, check to see if the input
2285  // is a trunc or zext of a bitcast from vector. If so, we can replace all
2286  // the casts with a shuffle and (potentially) a bitcast.
2287  if (isa<TruncInst>(Src) || isa<ZExtInst>(Src)) {
2288  CastInst *SrcCast = cast<CastInst>(Src);
2289  if (BitCastInst *BCIn = dyn_cast<BitCastInst>(SrcCast->getOperand(0)))
2290  if (isa<VectorType>(BCIn->getOperand(0)->getType()))
2291  if (Instruction *I = optimizeVectorResize(BCIn->getOperand(0),
2292  cast<VectorType>(DestTy), *this))
2293  return I;
2294  }
2295 
2296  // If the input is an 'or' instruction, we may be doing shifts and ors to
2297  // assemble the elements of the vector manually. Try to rip the code out
2298  // and replace it with insertelements.
2299  if (Value *V = optimizeIntegerToVectorInsertions(CI, *this))
2300  return replaceInstUsesWith(CI, V);
2301  }
2302  }
2303 
2304  if (VectorType *SrcVTy = dyn_cast<VectorType>(SrcTy)) {
2305  if (SrcVTy->getNumElements() == 1) {
2306  // If our destination is not a vector, then make this a straight
2307  // scalar-scalar cast.
2308  if (!DestTy->isVectorTy()) {
2309  Value *Elem =
2310  Builder.CreateExtractElement(Src,
2312  return CastInst::Create(Instruction::BitCast, Elem, DestTy);
2313  }
2314 
2315  // Otherwise, see if our source is an insert. If so, then use the scalar
2316  // component directly.
2317  if (InsertElementInst *IEI =
2318  dyn_cast<InsertElementInst>(CI.getOperand(0)))
2319  return CastInst::Create(Instruction::BitCast, IEI->getOperand(1),
2320  DestTy);
2321  }
2322  }
2323 
2324  if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(Src)) {
2325  // Okay, we have (bitcast (shuffle ..)). Check to see if this is
2326  // a bitcast to a vector with the same # elts.
2327  if (SVI->hasOneUse() && DestTy->isVectorTy() &&
2328  DestTy->getVectorNumElements() == SVI->getType()->getNumElements() &&
2329  SVI->getType()->getNumElements() ==
2330  SVI->getOperand(0)->getType()->getVectorNumElements()) {
2331  BitCastInst *Tmp;
2332  // If either of the operands is a cast from CI.getType(), then
2333  // evaluating the shuffle in the casted destination's type will allow
2334  // us to eliminate at least one cast.
2335  if (((Tmp = dyn_cast<BitCastInst>(SVI->getOperand(0))) &&
2336  Tmp->getOperand(0)->getType() == DestTy) ||
2337  ((Tmp = dyn_cast<BitCastInst>(SVI->getOperand(1))) &&
2338  Tmp->getOperand(0)->getType() == DestTy)) {
2339  Value *LHS = Builder.CreateBitCast(SVI->getOperand(0), DestTy);
2340  Value *RHS = Builder.CreateBitCast(SVI->getOperand(1), DestTy);
2341  // Return a new shuffle vector. Use the same element ID's, as we
2342  // know the vector types match #elts.
2343  return new ShuffleVectorInst(LHS, RHS, SVI->getOperand(2));
2344  }
2345  }
2346  }
2347 
2348  // Handle the A->B->A cast, and there is an intervening PHI node.
2349  if (PHINode *PN = dyn_cast<PHINode>(Src))
2350  if (Instruction *I = optimizeBitCastFromPhi(CI, PN))
2351  return I;
2352 
2353  if (Instruction *I = canonicalizeBitCastExtElt(CI, *this))
2354  return I;
2355 
2356  if (Instruction *I = foldBitCastBitwiseLogic(CI, Builder))
2357  return I;
2358 
2359  if (Instruction *I = foldBitCastSelect(CI, Builder))
2360  return I;
2361 
2362  if (SrcTy->isPointerTy())
2363  return commonPointerCastTransforms(CI);
2364  return commonCastTransforms(CI);
2365 }
2366 
2368  // If the destination pointer element type is not the same as the source's
2369  // first do a bitcast to the destination type, and then the addrspacecast.
2370  // This allows the cast to be exposed to other transforms.
2371  Value *Src = CI.getOperand(0);
2372  PointerType *SrcTy = cast<PointerType>(Src->getType()->getScalarType());
2373  PointerType *DestTy = cast<PointerType>(CI.getType()->getScalarType());
2374 
2375  Type *DestElemTy = DestTy->getElementType();
2376  if (SrcTy->getElementType() != DestElemTy) {
2377  Type *MidTy = PointerType::get(DestElemTy, SrcTy->getAddressSpace());
2378  if (VectorType *VT = dyn_cast<VectorType>(CI.getType())) {
2379  // Handle vectors of pointers.
2380  MidTy = VectorType::get(MidTy, VT->getNumElements());
2381  }
2382 
2383  Value *NewBitCast = Builder.CreateBitCast(Src, MidTy);
2384  return new AddrSpaceCastInst(NewBitCast, CI.getType());
2385  }
2386 
2387  return commonPointerCastTransforms(CI);
2388 }
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.
void insertReplacementDbgValues(Value &From, Value &To, Instruction &InsertBefore, function_ref< DIExpression *(DbgInfoIntrinsic &OldDII)> RewriteExpr)
Assuming the value From is going to be deleted, insert replacement dbg.value intrinsics for each debu...
Definition: Local.cpp:1674
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:166
Instruction * visitUIToFP(CastInst &CI)
cst_pred_ty< is_zero_int > m_ZeroInt()
Match an integer 0 or a vector with all elements equal to 0.
Definition: PatternMatch.h:361
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:1270
static Constant * getLShr(Constant *C1, Constant *C2, bool isExact=false)
Definition: Constants.cpp:2254
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
cst_pred_ty< is_all_ones > m_AllOnes()
Match an integer or vector with all bits set.
Definition: PatternMatch.h:306
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)
DIExpression * getExpression() const
Definition: IntrinsicInst.h:84
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.
This is the common base class for debug info intrinsics.
Definition: IntrinsicInst.h:67
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:56
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.
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:2494
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