LLVM  6.0.0svn
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/PatternMatch.h"
20 #include "llvm/Support/KnownBits.h"
21 using namespace llvm;
22 using namespace PatternMatch;
23 
24 #define DEBUG_TYPE "instcombine"
25 
26 /// Analyze 'Val', seeing if it is a simple linear expression.
27 /// If so, decompose it, returning some value X, such that Val is
28 /// X*Scale+Offset.
29 ///
30 static Value *decomposeSimpleLinearExpr(Value *Val, unsigned &Scale,
31  uint64_t &Offset) {
32  if (ConstantInt *CI = dyn_cast<ConstantInt>(Val)) {
33  Offset = CI->getZExtValue();
34  Scale = 0;
35  return ConstantInt::get(Val->getType(), 0);
36  }
37 
38  if (BinaryOperator *I = dyn_cast<BinaryOperator>(Val)) {
39  // Cannot look past anything that might overflow.
41  if (OBI && !OBI->hasNoUnsignedWrap() && !OBI->hasNoSignedWrap()) {
42  Scale = 1;
43  Offset = 0;
44  return Val;
45  }
46 
47  if (ConstantInt *RHS = dyn_cast<ConstantInt>(I->getOperand(1))) {
48  if (I->getOpcode() == Instruction::Shl) {
49  // This is a value scaled by '1 << the shift amt'.
50  Scale = UINT64_C(1) << RHS->getZExtValue();
51  Offset = 0;
52  return I->getOperand(0);
53  }
54 
55  if (I->getOpcode() == Instruction::Mul) {
56  // This value is scaled by 'RHS'.
57  Scale = RHS->getZExtValue();
58  Offset = 0;
59  return I->getOperand(0);
60  }
61 
62  if (I->getOpcode() == Instruction::Add) {
63  // We have X+C. Check to see if we really have (X*C2)+C1,
64  // where C1 is divisible by C2.
65  unsigned SubScale;
66  Value *SubVal =
67  decomposeSimpleLinearExpr(I->getOperand(0), SubScale, Offset);
68  Offset += RHS->getZExtValue();
69  Scale = SubScale;
70  return SubVal;
71  }
72  }
73  }
74 
75  // Otherwise, we can't look past this.
76  Scale = 1;
77  Offset = 0;
78  return Val;
79 }
80 
81 /// If we find a cast of an allocation instruction, try to eliminate the cast by
82 /// moving the type information into the alloc.
83 Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI,
84  AllocaInst &AI) {
85  PointerType *PTy = cast<PointerType>(CI.getType());
86 
87  BuilderTy AllocaBuilder(Builder);
88  AllocaBuilder.SetInsertPoint(&AI);
89 
90  // Get the type really allocated and the type casted to.
91  Type *AllocElTy = AI.getAllocatedType();
92  Type *CastElTy = PTy->getElementType();
93  if (!AllocElTy->isSized() || !CastElTy->isSized()) return nullptr;
94 
95  unsigned AllocElTyAlign = DL.getABITypeAlignment(AllocElTy);
96  unsigned CastElTyAlign = DL.getABITypeAlignment(CastElTy);
97  if (CastElTyAlign < AllocElTyAlign) return nullptr;
98 
99  // If the allocation has multiple uses, only promote it if we are strictly
100  // increasing the alignment of the resultant allocation. If we keep it the
101  // same, we open the door to infinite loops of various kinds.
102  if (!AI.hasOneUse() && CastElTyAlign == AllocElTyAlign) return nullptr;
103 
104  uint64_t AllocElTySize = DL.getTypeAllocSize(AllocElTy);
105  uint64_t CastElTySize = DL.getTypeAllocSize(CastElTy);
106  if (CastElTySize == 0 || AllocElTySize == 0) return nullptr;
107 
108  // If the allocation has multiple uses, only promote it if we're not
109  // shrinking the amount of memory being allocated.
110  uint64_t AllocElTyStoreSize = DL.getTypeStoreSize(AllocElTy);
111  uint64_t CastElTyStoreSize = DL.getTypeStoreSize(CastElTy);
112  if (!AI.hasOneUse() && CastElTyStoreSize < AllocElTyStoreSize) return nullptr;
113 
114  // See if we can satisfy the modulus by pulling a scale out of the array
115  // size argument.
116  unsigned ArraySizeScale;
117  uint64_t ArrayOffset;
118  Value *NumElements = // See if the array size is a decomposable linear expr.
119  decomposeSimpleLinearExpr(AI.getOperand(0), ArraySizeScale, ArrayOffset);
120 
121  // If we can now satisfy the modulus, by using a non-1 scale, we really can
122  // do the xform.
123  if ((AllocElTySize*ArraySizeScale) % CastElTySize != 0 ||
124  (AllocElTySize*ArrayOffset ) % CastElTySize != 0) return nullptr;
125 
126  unsigned Scale = (AllocElTySize*ArraySizeScale)/CastElTySize;
127  Value *Amt = nullptr;
128  if (Scale == 1) {
129  Amt = NumElements;
130  } else {
131  Amt = ConstantInt::get(AI.getArraySize()->getType(), Scale);
132  // Insert before the alloca, not before the cast.
133  Amt = AllocaBuilder.CreateMul(Amt, NumElements);
134  }
135 
136  if (uint64_t Offset = (AllocElTySize*ArrayOffset)/CastElTySize) {
138  Offset, true);
139  Amt = AllocaBuilder.CreateAdd(Amt, Off);
140  }
141 
142  AllocaInst *New = AllocaBuilder.CreateAlloca(CastElTy, Amt);
143  New->setAlignment(AI.getAlignment());
144  New->takeName(&AI);
146 
147  // If the allocation has multiple real uses, insert a cast and change all
148  // things that used it to use the new cast. This will also hack on CI, but it
149  // will die soon.
150  if (!AI.hasOneUse()) {
151  // New is the allocation instruction, pointer typed. AI is the original
152  // allocation instruction, also pointer typed. Thus, cast to use is BitCast.
153  Value *NewCast = AllocaBuilder.CreateBitCast(New, AI.getType(), "tmpcast");
154  replaceInstUsesWith(AI, NewCast);
155  }
156  return replaceInstUsesWith(CI, New);
157 }
158 
159 /// Given an expression that CanEvaluateTruncated or CanEvaluateSExtd returns
160 /// true for, actually insert the code to evaluate the expression.
161 Value *InstCombiner::EvaluateInDifferentType(Value *V, Type *Ty,
162  bool isSigned) {
163  if (Constant *C = dyn_cast<Constant>(V)) {
164  C = ConstantExpr::getIntegerCast(C, Ty, isSigned /*Sext or ZExt*/);
165  // If we got a constantexpr back, try to simplify it with DL info.
166  if (Constant *FoldedC = ConstantFoldConstant(C, DL, &TLI))
167  C = FoldedC;
168  return C;
169  }
170 
171  // Otherwise, it must be an instruction.
172  Instruction *I = cast<Instruction>(V);
173  Instruction *Res = nullptr;
174  unsigned Opc = I->getOpcode();
175  switch (Opc) {
176  case Instruction::Add:
177  case Instruction::Sub:
178  case Instruction::Mul:
179  case Instruction::And:
180  case Instruction::Or:
181  case Instruction::Xor:
182  case Instruction::AShr:
183  case Instruction::LShr:
184  case Instruction::Shl:
185  case Instruction::UDiv:
186  case Instruction::URem: {
187  Value *LHS = EvaluateInDifferentType(I->getOperand(0), Ty, isSigned);
188  Value *RHS = EvaluateInDifferentType(I->getOperand(1), Ty, isSigned);
189  Res = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
190  break;
191  }
192  case Instruction::Trunc:
193  case Instruction::ZExt:
194  case Instruction::SExt:
195  // If the source type of the cast is the type we're trying for then we can
196  // just return the source. There's no need to insert it because it is not
197  // new.
198  if (I->getOperand(0)->getType() == Ty)
199  return I->getOperand(0);
200 
201  // Otherwise, must be the same type of cast, so just reinsert a new one.
202  // This also handles the case of zext(trunc(x)) -> zext(x).
203  Res = CastInst::CreateIntegerCast(I->getOperand(0), Ty,
204  Opc == Instruction::SExt);
205  break;
206  case Instruction::Select: {
207  Value *True = EvaluateInDifferentType(I->getOperand(1), Ty, isSigned);
208  Value *False = EvaluateInDifferentType(I->getOperand(2), Ty, isSigned);
209  Res = SelectInst::Create(I->getOperand(0), True, False);
210  break;
211  }
212  case Instruction::PHI: {
213  PHINode *OPN = cast<PHINode>(I);
214  PHINode *NPN = PHINode::Create(Ty, OPN->getNumIncomingValues());
215  for (unsigned i = 0, e = OPN->getNumIncomingValues(); i != e; ++i) {
216  Value *V =
217  EvaluateInDifferentType(OPN->getIncomingValue(i), Ty, isSigned);
218  NPN->addIncoming(V, OPN->getIncomingBlock(i));
219  }
220  Res = NPN;
221  break;
222  }
223  default:
224  // TODO: Can handle more cases here.
225  llvm_unreachable("Unreachable!");
226  }
227 
228  Res->takeName(I);
229  return InsertNewInstWith(Res, *I);
230 }
231 
232 Instruction::CastOps InstCombiner::isEliminableCastPair(const CastInst *CI1,
233  const CastInst *CI2) {
234  Type *SrcTy = CI1->getSrcTy();
235  Type *MidTy = CI1->getDestTy();
236  Type *DstTy = CI2->getDestTy();
237 
238  Instruction::CastOps firstOp = CI1->getOpcode();
239  Instruction::CastOps secondOp = CI2->getOpcode();
240  Type *SrcIntPtrTy =
241  SrcTy->isPtrOrPtrVectorTy() ? DL.getIntPtrType(SrcTy) : nullptr;
242  Type *MidIntPtrTy =
243  MidTy->isPtrOrPtrVectorTy() ? DL.getIntPtrType(MidTy) : nullptr;
244  Type *DstIntPtrTy =
245  DstTy->isPtrOrPtrVectorTy() ? DL.getIntPtrType(DstTy) : nullptr;
246  unsigned Res = CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy,
247  DstTy, SrcIntPtrTy, MidIntPtrTy,
248  DstIntPtrTy);
249 
250  // We don't want to form an inttoptr or ptrtoint that converts to an integer
251  // type that differs from the pointer size.
252  if ((Res == Instruction::IntToPtr && SrcTy != DstIntPtrTy) ||
253  (Res == Instruction::PtrToInt && DstTy != SrcIntPtrTy))
254  Res = 0;
255 
256  return Instruction::CastOps(Res);
257 }
258 
259 /// @brief Implement the transforms common to all CastInst visitors.
261  Value *Src = CI.getOperand(0);
262 
263  // Try to eliminate a cast of a cast.
264  if (auto *CSrc = dyn_cast<CastInst>(Src)) { // A->B->C cast
265  if (Instruction::CastOps NewOpc = isEliminableCastPair(CSrc, &CI)) {
266  // The first cast (CSrc) is eliminable so we need to fix up or replace
267  // the second cast (CI). CSrc will then have a good chance of being dead.
268  return CastInst::Create(NewOpc, CSrc->getOperand(0), CI.getType());
269  }
270  }
271 
272  // If we are casting a select, then fold the cast into the select.
273  if (auto *SI = dyn_cast<SelectInst>(Src))
274  if (Instruction *NV = FoldOpIntoSelect(CI, SI))
275  return NV;
276 
277  // If we are casting a PHI, then fold the cast into the PHI.
278  if (auto *PN = dyn_cast<PHINode>(Src)) {
279  // Don't do this if it would create a PHI node with an illegal type from a
280  // legal type.
281  if (!Src->getType()->isIntegerTy() || !CI.getType()->isIntegerTy() ||
282  shouldChangeType(CI.getType(), Src->getType()))
283  if (Instruction *NV = foldOpIntoPhi(CI, PN))
284  return NV;
285  }
286 
287  return nullptr;
288 }
289 
290 /// Return true if we can evaluate the specified expression tree as type Ty
291 /// instead of its larger type, and arrive with the same value.
292 /// This is used by code that tries to eliminate truncates.
293 ///
294 /// Ty will always be a type smaller than V. We should return true if trunc(V)
295 /// can be computed by computing V in the smaller type. If V is an instruction,
296 /// then trunc(inst(x,y)) can be computed as inst(trunc(x),trunc(y)), which only
297 /// makes sense if x and y can be efficiently truncated.
298 ///
299 /// This function works on both vectors and scalars.
300 ///
301 static bool canEvaluateTruncated(Value *V, Type *Ty, InstCombiner &IC,
302  Instruction *CxtI) {
303  // We can always evaluate constants in another type.
304  if (isa<Constant>(V))
305  return true;
306 
308  if (!I) return false;
309 
310  Type *OrigTy = V->getType();
311 
312  // If this is an extension from the dest type, we can eliminate it, even if it
313  // has multiple uses.
314  if ((isa<ZExtInst>(I) || isa<SExtInst>(I)) &&
315  I->getOperand(0)->getType() == Ty)
316  return true;
317 
318  // We can't extend or shrink something that has multiple uses: doing so would
319  // require duplicating the instruction in general, which isn't profitable.
320  if (!I->hasOneUse()) return false;
321 
322  unsigned Opc = I->getOpcode();
323  switch (Opc) {
324  case Instruction::Add:
325  case Instruction::Sub:
326  case Instruction::Mul:
327  case Instruction::And:
328  case Instruction::Or:
329  case Instruction::Xor:
330  // These operators can all arbitrarily be extended or truncated.
331  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI) &&
332  canEvaluateTruncated(I->getOperand(1), Ty, IC, CxtI);
333 
334  case Instruction::UDiv:
335  case Instruction::URem: {
336  // UDiv and URem can be truncated if all the truncated bits are zero.
337  uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
338  uint32_t BitWidth = Ty->getScalarSizeInBits();
339  if (BitWidth < OrigBitWidth) {
340  APInt Mask = APInt::getHighBitsSet(OrigBitWidth, OrigBitWidth-BitWidth);
341  if (IC.MaskedValueIsZero(I->getOperand(0), Mask, 0, CxtI) &&
342  IC.MaskedValueIsZero(I->getOperand(1), Mask, 0, CxtI)) {
343  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI) &&
344  canEvaluateTruncated(I->getOperand(1), Ty, IC, CxtI);
345  }
346  }
347  break;
348  }
349  case Instruction::Shl: {
350  // If we are truncating the result of this SHL, and if it's a shift of a
351  // constant amount, we can always perform a SHL in a smaller type.
352  const APInt *Amt;
353  if (match(I->getOperand(1), m_APInt(Amt))) {
354  uint32_t BitWidth = Ty->getScalarSizeInBits();
355  if (Amt->getLimitedValue(BitWidth) < BitWidth)
356  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
357  }
358  break;
359  }
360  case Instruction::LShr: {
361  // If this is a truncate of a logical shr, we can truncate it to a smaller
362  // lshr iff we know that the bits we would otherwise be shifting in are
363  // already zeros.
364  const APInt *Amt;
365  if (match(I->getOperand(1), m_APInt(Amt))) {
366  uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
367  uint32_t BitWidth = Ty->getScalarSizeInBits();
368  if (IC.MaskedValueIsZero(I->getOperand(0),
369  APInt::getHighBitsSet(OrigBitWidth, OrigBitWidth-BitWidth), 0, CxtI) &&
370  Amt->getLimitedValue(BitWidth) < BitWidth) {
371  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
372  }
373  }
374  break;
375  }
376  case Instruction::AShr: {
377  // If this is a truncate of an arithmetic shr, we can truncate it to a
378  // smaller ashr iff we know that all the bits from the sign bit of the
379  // original type and the sign bit of the truncate type are similar.
380  // TODO: It is enough to check that the bits we would be shifting in are
381  // similar to sign bit of the truncate type.
382  const APInt *Amt;
383  if (match(I->getOperand(1), m_APInt(Amt))) {
384  uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
385  uint32_t BitWidth = Ty->getScalarSizeInBits();
386  if (Amt->getLimitedValue(BitWidth) < BitWidth &&
387  OrigBitWidth - BitWidth <
388  IC.ComputeNumSignBits(I->getOperand(0), 0, CxtI))
389  return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
390  }
391  break;
392  }
393  case Instruction::Trunc:
394  // trunc(trunc(x)) -> trunc(x)
395  return true;
396  case Instruction::ZExt:
397  case Instruction::SExt:
398  // trunc(ext(x)) -> ext(x) if the source type is smaller than the new dest
399  // trunc(ext(x)) -> trunc(x) if the source type is larger than the new dest
400  return true;
401  case Instruction::Select: {
402  SelectInst *SI = cast<SelectInst>(I);
403  return canEvaluateTruncated(SI->getTrueValue(), Ty, IC, CxtI) &&
404  canEvaluateTruncated(SI->getFalseValue(), Ty, IC, CxtI);
405  }
406  case Instruction::PHI: {
407  // We can change a phi if we can change all operands. Note that we never
408  // get into trouble with cyclic PHIs here because we only consider
409  // instructions with a single use.
410  PHINode *PN = cast<PHINode>(I);
411  for (Value *IncValue : PN->incoming_values())
412  if (!canEvaluateTruncated(IncValue, Ty, IC, CxtI))
413  return false;
414  return true;
415  }
416  default:
417  // TODO: Can handle more cases here.
418  break;
419  }
420 
421  return false;
422 }
423 
424 /// Given a vector that is bitcast to an integer, optionally logically
425 /// right-shifted, and truncated, convert it to an extractelement.
426 /// Example (big endian):
427 /// trunc (lshr (bitcast <4 x i32> %X to i128), 32) to i32
428 /// --->
429 /// extractelement <4 x i32> %X, 1
431  Value *TruncOp = Trunc.getOperand(0);
432  Type *DestType = Trunc.getType();
433  if (!TruncOp->hasOneUse() || !isa<IntegerType>(DestType))
434  return nullptr;
435 
436  Value *VecInput = nullptr;
437  ConstantInt *ShiftVal = nullptr;
438  if (!match(TruncOp, m_CombineOr(m_BitCast(m_Value(VecInput)),
439  m_LShr(m_BitCast(m_Value(VecInput)),
440  m_ConstantInt(ShiftVal)))) ||
441  !isa<VectorType>(VecInput->getType()))
442  return nullptr;
443 
444  VectorType *VecType = cast<VectorType>(VecInput->getType());
445  unsigned VecWidth = VecType->getPrimitiveSizeInBits();
446  unsigned DestWidth = DestType->getPrimitiveSizeInBits();
447  unsigned ShiftAmount = ShiftVal ? ShiftVal->getZExtValue() : 0;
448 
449  if ((VecWidth % DestWidth != 0) || (ShiftAmount % DestWidth != 0))
450  return nullptr;
451 
452  // If the element type of the vector doesn't match the result type,
453  // bitcast it to a vector type that we can extract from.
454  unsigned NumVecElts = VecWidth / DestWidth;
455  if (VecType->getElementType() != DestType) {
456  VecType = VectorType::get(DestType, NumVecElts);
457  VecInput = IC.Builder.CreateBitCast(VecInput, VecType, "bc");
458  }
459 
460  unsigned Elt = ShiftAmount / DestWidth;
461  if (IC.getDataLayout().isBigEndian())
462  Elt = NumVecElts - 1 - Elt;
463 
464  return ExtractElementInst::Create(VecInput, IC.Builder.getInt32(Elt));
465 }
466 
467 /// Rotate left/right may occur in a wider type than necessary because of type
468 /// promotion rules. Try to narrow all of the component instructions.
469 Instruction *InstCombiner::narrowRotate(TruncInst &Trunc) {
470  assert((isa<VectorType>(Trunc.getSrcTy()) ||
471  shouldChangeType(Trunc.getSrcTy(), Trunc.getType())) &&
472  "Don't narrow to an illegal scalar type");
473 
474  // First, find an or'd pair of opposite shifts with the same shifted operand:
475  // trunc (or (lshr ShVal, ShAmt0), (shl ShVal, ShAmt1))
476  Value *Or0, *Or1;
477  if (!match(Trunc.getOperand(0), m_OneUse(m_Or(m_Value(Or0), m_Value(Or1)))))
478  return nullptr;
479 
480  Value *ShVal, *ShAmt0, *ShAmt1;
481  if (!match(Or0, m_OneUse(m_LogicalShift(m_Value(ShVal), m_Value(ShAmt0)))) ||
482  !match(Or1, m_OneUse(m_LogicalShift(m_Specific(ShVal), m_Value(ShAmt1)))))
483  return nullptr;
484 
485  auto ShiftOpcode0 = cast<BinaryOperator>(Or0)->getOpcode();
486  auto ShiftOpcode1 = cast<BinaryOperator>(Or1)->getOpcode();
487  if (ShiftOpcode0 == ShiftOpcode1)
488  return nullptr;
489 
490  // The shift amounts must add up to the narrow bit width.
491  Value *ShAmt;
492  bool SubIsOnLHS;
493  Type *DestTy = Trunc.getType();
494  unsigned NarrowWidth = DestTy->getScalarSizeInBits();
495  if (match(ShAmt0,
496  m_OneUse(m_Sub(m_SpecificInt(NarrowWidth), m_Specific(ShAmt1))))) {
497  ShAmt = ShAmt1;
498  SubIsOnLHS = true;
499  } else if (match(ShAmt1, m_OneUse(m_Sub(m_SpecificInt(NarrowWidth),
500  m_Specific(ShAmt0))))) {
501  ShAmt = ShAmt0;
502  SubIsOnLHS = false;
503  } else {
504  return nullptr;
505  }
506 
507  // The shifted value must have high zeros in the wide type. Typically, this
508  // will be a zext, but it could also be the result of an 'and' or 'shift'.
509  unsigned WideWidth = Trunc.getSrcTy()->getScalarSizeInBits();
510  APInt HiBitMask = APInt::getHighBitsSet(WideWidth, WideWidth - NarrowWidth);
511  if (!MaskedValueIsZero(ShVal, HiBitMask, 0, &Trunc))
512  return nullptr;
513 
514  // We have an unnecessarily wide rotate!
515  // trunc (or (lshr ShVal, ShAmt), (shl ShVal, BitWidth - ShAmt))
516  // Narrow it down to eliminate the zext/trunc:
517  // or (lshr trunc(ShVal), ShAmt0'), (shl trunc(ShVal), ShAmt1')
518  Value *NarrowShAmt = Builder.CreateTrunc(ShAmt, DestTy);
519  Value *NegShAmt = Builder.CreateNeg(NarrowShAmt);
520 
521  // Mask both shift amounts to ensure there's no UB from oversized shifts.
522  Constant *MaskC = ConstantInt::get(DestTy, NarrowWidth - 1);
523  Value *MaskedShAmt = Builder.CreateAnd(NarrowShAmt, MaskC);
524  Value *MaskedNegShAmt = Builder.CreateAnd(NegShAmt, MaskC);
525 
526  // Truncate the original value and use narrow ops.
527  Value *X = Builder.CreateTrunc(ShVal, DestTy);
528  Value *NarrowShAmt0 = SubIsOnLHS ? MaskedNegShAmt : MaskedShAmt;
529  Value *NarrowShAmt1 = SubIsOnLHS ? MaskedShAmt : MaskedNegShAmt;
530  Value *NarrowSh0 = Builder.CreateBinOp(ShiftOpcode0, X, NarrowShAmt0);
531  Value *NarrowSh1 = Builder.CreateBinOp(ShiftOpcode1, X, NarrowShAmt1);
532  return BinaryOperator::CreateOr(NarrowSh0, NarrowSh1);
533 }
534 
535 /// Try to narrow the width of math or bitwise logic instructions by pulling a
536 /// truncate ahead of binary operators.
537 /// TODO: Transforms for truncated shifts should be moved into here.
538 Instruction *InstCombiner::narrowBinOp(TruncInst &Trunc) {
539  Type *SrcTy = Trunc.getSrcTy();
540  Type *DestTy = Trunc.getType();
541  if (!isa<VectorType>(SrcTy) && !shouldChangeType(SrcTy, DestTy))
542  return nullptr;
543 
544  BinaryOperator *BinOp;
545  if (!match(Trunc.getOperand(0), m_OneUse(m_BinOp(BinOp))))
546  return nullptr;
547 
548  Value *BinOp0 = BinOp->getOperand(0);
549  Value *BinOp1 = BinOp->getOperand(1);
550  switch (BinOp->getOpcode()) {
551  case Instruction::And:
552  case Instruction::Or:
553  case Instruction::Xor:
554  case Instruction::Add:
555  case Instruction::Sub:
556  case Instruction::Mul: {
557  Constant *C;
558  if (match(BinOp0, m_Constant(C))) {
559  // trunc (binop C, X) --> binop (trunc C', X)
560  Constant *NarrowC = ConstantExpr::getTrunc(C, DestTy);
561  Value *TruncX = Builder.CreateTrunc(BinOp1, DestTy);
562  return BinaryOperator::Create(BinOp->getOpcode(), NarrowC, TruncX);
563  }
564  if (match(BinOp1, m_Constant(C))) {
565  // trunc (binop X, C) --> binop (trunc X, C')
566  Constant *NarrowC = ConstantExpr::getTrunc(C, DestTy);
567  Value *TruncX = Builder.CreateTrunc(BinOp0, DestTy);
568  return BinaryOperator::Create(BinOp->getOpcode(), TruncX, NarrowC);
569  }
570  Value *X;
571  if (match(BinOp0, m_ZExtOrSExt(m_Value(X))) && X->getType() == DestTy) {
572  // trunc (binop (ext X), Y) --> binop X, (trunc Y)
573  Value *NarrowOp1 = Builder.CreateTrunc(BinOp1, DestTy);
574  return BinaryOperator::Create(BinOp->getOpcode(), X, NarrowOp1);
575  }
576  if (match(BinOp1, m_ZExtOrSExt(m_Value(X))) && X->getType() == DestTy) {
577  // trunc (binop Y, (ext X)) --> binop (trunc Y), X
578  Value *NarrowOp0 = Builder.CreateTrunc(BinOp0, DestTy);
579  return BinaryOperator::Create(BinOp->getOpcode(), NarrowOp0, X);
580  }
581  break;
582  }
583 
584  default: break;
585  }
586 
587  if (Instruction *NarrowOr = narrowRotate(Trunc))
588  return NarrowOr;
589 
590  return nullptr;
591 }
592 
593 /// Try to narrow the width of a splat shuffle. This could be generalized to any
594 /// shuffle with a constant operand, but we limit the transform to avoid
595 /// creating a shuffle type that targets may not be able to lower effectively.
597  InstCombiner::BuilderTy &Builder) {
598  auto *Shuf = dyn_cast<ShuffleVectorInst>(Trunc.getOperand(0));
599  if (Shuf && Shuf->hasOneUse() && isa<UndefValue>(Shuf->getOperand(1)) &&
600  Shuf->getMask()->getSplatValue() &&
601  Shuf->getType() == Shuf->getOperand(0)->getType()) {
602  // trunc (shuf X, Undef, SplatMask) --> shuf (trunc X), Undef, SplatMask
603  Constant *NarrowUndef = UndefValue::get(Trunc.getType());
604  Value *NarrowOp = Builder.CreateTrunc(Shuf->getOperand(0), Trunc.getType());
605  return new ShuffleVectorInst(NarrowOp, NarrowUndef, Shuf->getMask());
606  }
607 
608  return nullptr;
609 }
610 
611 /// Try to narrow the width of an insert element. This could be generalized for
612 /// any vector constant, but we limit the transform to insertion into undef to
613 /// avoid potential backend problems from unsupported insertion widths. This
614 /// could also be extended to handle the case of inserting a scalar constant
615 /// into a vector variable.
617  InstCombiner::BuilderTy &Builder) {
618  Instruction::CastOps Opcode = Trunc.getOpcode();
619  assert((Opcode == Instruction::Trunc || Opcode == Instruction::FPTrunc) &&
620  "Unexpected instruction for shrinking");
621 
622  auto *InsElt = dyn_cast<InsertElementInst>(Trunc.getOperand(0));
623  if (!InsElt || !InsElt->hasOneUse())
624  return nullptr;
625 
626  Type *DestTy = Trunc.getType();
627  Type *DestScalarTy = DestTy->getScalarType();
628  Value *VecOp = InsElt->getOperand(0);
629  Value *ScalarOp = InsElt->getOperand(1);
630  Value *Index = InsElt->getOperand(2);
631 
632  if (isa<UndefValue>(VecOp)) {
633  // trunc (inselt undef, X, Index) --> inselt undef, (trunc X), Index
634  // fptrunc (inselt undef, X, Index) --> inselt undef, (fptrunc X), Index
635  UndefValue *NarrowUndef = UndefValue::get(DestTy);
636  Value *NarrowOp = Builder.CreateCast(Opcode, ScalarOp, DestScalarTy);
637  return InsertElementInst::Create(NarrowUndef, NarrowOp, Index);
638  }
639 
640  return nullptr;
641 }
642 
644  if (Instruction *Result = commonCastTransforms(CI))
645  return Result;
646 
647  // Test if the trunc is the user of a select which is part of a
648  // minimum or maximum operation. If so, don't do any more simplification.
649  // Even simplifying demanded bits can break the canonical form of a
650  // min/max.
651  Value *LHS, *RHS;
652  if (SelectInst *SI = dyn_cast<SelectInst>(CI.getOperand(0)))
653  if (matchSelectPattern(SI, LHS, RHS).Flavor != SPF_UNKNOWN)
654  return nullptr;
655 
656  // See if we can simplify any instructions used by the input whose sole
657  // purpose is to compute bits we don't care about.
658  if (SimplifyDemandedInstructionBits(CI))
659  return &CI;
660 
661  Value *Src = CI.getOperand(0);
662  Type *DestTy = CI.getType(), *SrcTy = Src->getType();
663 
664  // Attempt to truncate the entire input expression tree to the destination
665  // type. Only do this if the dest type is a simple type, don't convert the
666  // expression tree to something weird like i93 unless the source is also
667  // strange.
668  if ((DestTy->isVectorTy() || shouldChangeType(SrcTy, DestTy)) &&
669  canEvaluateTruncated(Src, DestTy, *this, &CI)) {
670 
671  // If this cast is a truncate, evaluting in a different type always
672  // eliminates the cast, so it is always a win.
673  DEBUG(dbgs() << "ICE: EvaluateInDifferentType converting expression type"
674  " to avoid cast: " << CI << '\n');
675  Value *Res = EvaluateInDifferentType(Src, DestTy, false);
676  assert(Res->getType() == DestTy);
677  return replaceInstUsesWith(CI, Res);
678  }
679 
680  // Canonicalize trunc x to i1 -> (icmp ne (and x, 1), 0), likewise for vector.
681  if (DestTy->getScalarSizeInBits() == 1) {
682  Constant *One = ConstantInt::get(SrcTy, 1);
683  Src = Builder.CreateAnd(Src, One);
684  Value *Zero = Constant::getNullValue(Src->getType());
685  return new ICmpInst(ICmpInst::ICMP_NE, Src, Zero);
686  }
687 
688  // FIXME: Maybe combine the next two transforms to handle the no cast case
689  // more efficiently. Support vector types. Cleanup code by using m_OneUse.
690 
691  // Transform trunc(lshr (zext A), Cst) to eliminate one type conversion.
692  Value *A = nullptr; ConstantInt *Cst = nullptr;
693  if (Src->hasOneUse() &&
694  match(Src, m_LShr(m_ZExt(m_Value(A)), m_ConstantInt(Cst)))) {
695  // We have three types to worry about here, the type of A, the source of
696  // the truncate (MidSize), and the destination of the truncate. We know that
697  // ASize < MidSize and MidSize > ResultSize, but don't know the relation
698  // between ASize and ResultSize.
699  unsigned ASize = A->getType()->getPrimitiveSizeInBits();
700 
701  // If the shift amount is larger than the size of A, then the result is
702  // known to be zero because all the input bits got shifted out.
703  if (Cst->getZExtValue() >= ASize)
704  return replaceInstUsesWith(CI, Constant::getNullValue(DestTy));
705 
706  // Since we're doing an lshr and a zero extend, and know that the shift
707  // amount is smaller than ASize, it is always safe to do the shift in A's
708  // type, then zero extend or truncate to the result.
709  Value *Shift = Builder.CreateLShr(A, Cst->getZExtValue());
710  Shift->takeName(Src);
711  return CastInst::CreateIntegerCast(Shift, DestTy, false);
712  }
713 
714  // FIXME: We should canonicalize to zext/trunc and remove this transform.
715  // Transform trunc(lshr (sext A), Cst) to ashr A, Cst to eliminate type
716  // conversion.
717  // It works because bits coming from sign extension have the same value as
718  // the sign bit of the original value; performing ashr instead of lshr
719  // generates bits of the same value as the sign bit.
720  if (Src->hasOneUse() &&
721  match(Src, m_LShr(m_SExt(m_Value(A)), m_ConstantInt(Cst)))) {
722  Value *SExt = cast<Instruction>(Src)->getOperand(0);
723  const unsigned SExtSize = SExt->getType()->getPrimitiveSizeInBits();
724  const unsigned ASize = A->getType()->getPrimitiveSizeInBits();
725  const unsigned CISize = CI.getType()->getPrimitiveSizeInBits();
726  const unsigned MaxAmt = SExtSize - std::max(CISize, ASize);
727  unsigned ShiftAmt = Cst->getZExtValue();
728 
729  // This optimization can be only performed when zero bits generated by
730  // the original lshr aren't pulled into the value after truncation, so we
731  // can only shift by values no larger than the number of extension bits.
732  // FIXME: Instead of bailing when the shift is too large, use and to clear
733  // the extra bits.
734  if (ShiftAmt <= MaxAmt) {
735  if (CISize == ASize)
736  return BinaryOperator::CreateAShr(A, ConstantInt::get(CI.getType(),
737  std::min(ShiftAmt, ASize - 1)));
738  if (SExt->hasOneUse()) {
739  Value *Shift = Builder.CreateAShr(A, std::min(ShiftAmt, ASize - 1));
740  Shift->takeName(Src);
741  return CastInst::CreateIntegerCast(Shift, CI.getType(), true);
742  }
743  }
744  }
745 
746  if (Instruction *I = narrowBinOp(CI))
747  return I;
748 
749  if (Instruction *I = shrinkSplatShuffle(CI, Builder))
750  return I;
751 
752  if (Instruction *I = shrinkInsertElt(CI, Builder))
753  return I;
754 
755  if (Src->hasOneUse() && isa<IntegerType>(SrcTy) &&
756  shouldChangeType(SrcTy, DestTy)) {
757  // Transform "trunc (shl X, cst)" -> "shl (trunc X), cst" so long as the
758  // dest type is native and cst < dest size.
759  if (match(Src, m_Shl(m_Value(A), m_ConstantInt(Cst))) &&
760  !match(A, m_Shr(m_Value(), m_Constant()))) {
761  // Skip shifts of shift by constants. It undoes a combine in
762  // FoldShiftByConstant and is the extend in reg pattern.
763  const unsigned DestSize = DestTy->getScalarSizeInBits();
764  if (Cst->getValue().ult(DestSize)) {
765  Value *NewTrunc = Builder.CreateTrunc(A, DestTy, A->getName() + ".tr");
766 
767  return BinaryOperator::Create(
768  Instruction::Shl, NewTrunc,
769  ConstantInt::get(DestTy, Cst->getValue().trunc(DestSize)));
770  }
771  }
772  }
773 
774  if (Instruction *I = foldVecTruncToExtElt(CI, *this))
775  return I;
776 
777  return nullptr;
778 }
779 
780 Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, ZExtInst &CI,
781  bool DoTransform) {
782  // If we are just checking for a icmp eq of a single bit and zext'ing it
783  // to an integer, then shift the bit to the appropriate place and then
784  // cast to integer to avoid the comparison.
785  const APInt *Op1CV;
786  if (match(ICI->getOperand(1), m_APInt(Op1CV))) {
787 
788  // zext (x <s 0) to i32 --> x>>u31 true if signbit set.
789  // zext (x >s -1) to i32 --> (x>>u31)^1 true if signbit clear.
790  if ((ICI->getPredicate() == ICmpInst::ICMP_SLT && Op1CV->isNullValue()) ||
791  (ICI->getPredicate() == ICmpInst::ICMP_SGT && Op1CV->isAllOnesValue())) {
792  if (!DoTransform) return ICI;
793 
794  Value *In = ICI->getOperand(0);
795  Value *Sh = ConstantInt::get(In->getType(),
796  In->getType()->getScalarSizeInBits() - 1);
797  In = Builder.CreateLShr(In, Sh, In->getName() + ".lobit");
798  if (In->getType() != CI.getType())
799  In = Builder.CreateIntCast(In, CI.getType(), false /*ZExt*/);
800 
801  if (ICI->getPredicate() == ICmpInst::ICMP_SGT) {
802  Constant *One = ConstantInt::get(In->getType(), 1);
803  In = Builder.CreateXor(In, One, In->getName() + ".not");
804  }
805 
806  return replaceInstUsesWith(CI, In);
807  }
808 
809  // zext (X == 0) to i32 --> X^1 iff X has only the low bit set.
810  // zext (X == 0) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
811  // zext (X == 1) to i32 --> X iff X has only the low bit set.
812  // zext (X == 2) to i32 --> X>>1 iff X has only the 2nd bit set.
813  // zext (X != 0) to i32 --> X iff X has only the low bit set.
814  // zext (X != 0) to i32 --> X>>1 iff X has only the 2nd bit set.
815  // zext (X != 1) to i32 --> X^1 iff X has only the low bit set.
816  // zext (X != 2) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
817  if ((Op1CV->isNullValue() || Op1CV->isPowerOf2()) &&
818  // This only works for EQ and NE
819  ICI->isEquality()) {
820  // If Op1C some other power of two, convert:
821  KnownBits Known = computeKnownBits(ICI->getOperand(0), 0, &CI);
822 
823  APInt KnownZeroMask(~Known.Zero);
824  if (KnownZeroMask.isPowerOf2()) { // Exactly 1 possible 1?
825  if (!DoTransform) return ICI;
826 
827  bool isNE = ICI->getPredicate() == ICmpInst::ICMP_NE;
828  if (!Op1CV->isNullValue() && (*Op1CV != KnownZeroMask)) {
829  // (X&4) == 2 --> false
830  // (X&4) != 2 --> true
831  Constant *Res = ConstantInt::get(CI.getType(), isNE);
832  return replaceInstUsesWith(CI, Res);
833  }
834 
835  uint32_t ShAmt = KnownZeroMask.logBase2();
836  Value *In = ICI->getOperand(0);
837  if (ShAmt) {
838  // Perform a logical shr by shiftamt.
839  // Insert the shift to put the result in the low bit.
840  In = Builder.CreateLShr(In, ConstantInt::get(In->getType(), ShAmt),
841  In->getName() + ".lobit");
842  }
843 
844  if (!Op1CV->isNullValue() == isNE) { // Toggle the low bit.
845  Constant *One = ConstantInt::get(In->getType(), 1);
846  In = Builder.CreateXor(In, One);
847  }
848 
849  if (CI.getType() == In->getType())
850  return replaceInstUsesWith(CI, In);
851 
852  Value *IntCast = Builder.CreateIntCast(In, CI.getType(), false);
853  return replaceInstUsesWith(CI, IntCast);
854  }
855  }
856  }
857 
858  // icmp ne A, B is equal to xor A, B when A and B only really have one bit.
859  // It is also profitable to transform icmp eq into not(xor(A, B)) because that
860  // may lead to additional simplifications.
861  if (ICI->isEquality() && CI.getType() == ICI->getOperand(0)->getType()) {
862  if (IntegerType *ITy = dyn_cast<IntegerType>(CI.getType())) {
863  Value *LHS = ICI->getOperand(0);
864  Value *RHS = ICI->getOperand(1);
865 
866  KnownBits KnownLHS = computeKnownBits(LHS, 0, &CI);
867  KnownBits KnownRHS = computeKnownBits(RHS, 0, &CI);
868 
869  if (KnownLHS.Zero == KnownRHS.Zero && KnownLHS.One == KnownRHS.One) {
870  APInt KnownBits = KnownLHS.Zero | KnownLHS.One;
871  APInt UnknownBit = ~KnownBits;
872  if (UnknownBit.countPopulation() == 1) {
873  if (!DoTransform) return ICI;
874 
875  Value *Result = Builder.CreateXor(LHS, RHS);
876 
877  // Mask off any bits that are set and won't be shifted away.
878  if (KnownLHS.One.uge(UnknownBit))
879  Result = Builder.CreateAnd(Result,
880  ConstantInt::get(ITy, UnknownBit));
881 
882  // Shift the bit we're testing down to the lsb.
883  Result = Builder.CreateLShr(
884  Result, ConstantInt::get(ITy, UnknownBit.countTrailingZeros()));
885 
886  if (ICI->getPredicate() == ICmpInst::ICMP_EQ)
887  Result = Builder.CreateXor(Result, ConstantInt::get(ITy, 1));
888  Result->takeName(ICI);
889  return replaceInstUsesWith(CI, Result);
890  }
891  }
892  }
893  }
894 
895  return nullptr;
896 }
897 
898 /// Determine if the specified value can be computed in the specified wider type
899 /// and produce the same low bits. If not, return false.
900 ///
901 /// If this function returns true, it can also return a non-zero number of bits
902 /// (in BitsToClear) which indicates that the value it computes is correct for
903 /// the zero extend, but that the additional BitsToClear bits need to be zero'd
904 /// out. For example, to promote something like:
905 ///
906 /// %B = trunc i64 %A to i32
907 /// %C = lshr i32 %B, 8
908 /// %E = zext i32 %C to i64
909 ///
910 /// CanEvaluateZExtd for the 'lshr' will return true, and BitsToClear will be
911 /// set to 8 to indicate that the promoted value needs to have bits 24-31
912 /// cleared in addition to bits 32-63. Since an 'and' will be generated to
913 /// clear the top bits anyway, doing this has no extra cost.
914 ///
915 /// This function works on both vectors and scalars.
916 static bool canEvaluateZExtd(Value *V, Type *Ty, unsigned &BitsToClear,
917  InstCombiner &IC, Instruction *CxtI) {
918  BitsToClear = 0;
919  if (isa<Constant>(V))
920  return true;
921 
923  if (!I) return false;
924 
925  // If the input is a truncate from the destination type, we can trivially
926  // eliminate it.
927  if (isa<TruncInst>(I) && I->getOperand(0)->getType() == Ty)
928  return true;
929 
930  // We can't extend or shrink something that has multiple uses: doing so would
931  // require duplicating the instruction in general, which isn't profitable.
932  if (!I->hasOneUse()) return false;
933 
934  unsigned Opc = I->getOpcode(), Tmp;
935  switch (Opc) {
936  case Instruction::ZExt: // zext(zext(x)) -> zext(x).
937  case Instruction::SExt: // zext(sext(x)) -> sext(x).
938  case Instruction::Trunc: // zext(trunc(x)) -> trunc(x) or zext(x)
939  return true;
940  case Instruction::And:
941  case Instruction::Or:
942  case Instruction::Xor:
943  case Instruction::Add:
944  case Instruction::Sub:
945  case Instruction::Mul:
946  if (!canEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI) ||
947  !canEvaluateZExtd(I->getOperand(1), Ty, Tmp, IC, CxtI))
948  return false;
949  // These can all be promoted if neither operand has 'bits to clear'.
950  if (BitsToClear == 0 && Tmp == 0)
951  return true;
952 
953  // If the operation is an AND/OR/XOR and the bits to clear are zero in the
954  // other side, BitsToClear is ok.
955  if (Tmp == 0 && I->isBitwiseLogicOp()) {
956  // We use MaskedValueIsZero here for generality, but the case we care
957  // about the most is constant RHS.
958  unsigned VSize = V->getType()->getScalarSizeInBits();
959  if (IC.MaskedValueIsZero(I->getOperand(1),
960  APInt::getHighBitsSet(VSize, BitsToClear),
961  0, CxtI)) {
962  // If this is an And instruction and all of the BitsToClear are
963  // known to be zero we can reset BitsToClear.
964  if (Opc == Instruction::And)
965  BitsToClear = 0;
966  return true;
967  }
968  }
969 
970  // Otherwise, we don't know how to analyze this BitsToClear case yet.
971  return false;
972 
973  case Instruction::Shl: {
974  // We can promote shl(x, cst) if we can promote x. Since shl overwrites the
975  // upper bits we can reduce BitsToClear by the shift amount.
976  const APInt *Amt;
977  if (match(I->getOperand(1), m_APInt(Amt))) {
978  if (!canEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI))
979  return false;
980  uint64_t ShiftAmt = Amt->getZExtValue();
981  BitsToClear = ShiftAmt < BitsToClear ? BitsToClear - ShiftAmt : 0;
982  return true;
983  }
984  return false;
985  }
986  case Instruction::LShr: {
987  // We can promote lshr(x, cst) if we can promote x. This requires the
988  // ultimate 'and' to clear out the high zero bits we're clearing out though.
989  const APInt *Amt;
990  if (match(I->getOperand(1), m_APInt(Amt))) {
991  if (!canEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI))
992  return false;
993  BitsToClear += Amt->getZExtValue();
994  if (BitsToClear > V->getType()->getScalarSizeInBits())
995  BitsToClear = V->getType()->getScalarSizeInBits();
996  return true;
997  }
998  // Cannot promote variable LSHR.
999  return false;
1000  }
1001  case Instruction::Select:
1002  if (!canEvaluateZExtd(I->getOperand(1), Ty, Tmp, IC, CxtI) ||
1003  !canEvaluateZExtd(I->getOperand(2), Ty, BitsToClear, IC, CxtI) ||
1004  // TODO: If important, we could handle the case when the BitsToClear are
1005  // known zero in the disagreeing side.
1006  Tmp != BitsToClear)
1007  return false;
1008  return true;
1009 
1010  case Instruction::PHI: {
1011  // We can change a phi if we can change all operands. Note that we never
1012  // get into trouble with cyclic PHIs here because we only consider
1013  // instructions with a single use.
1014  PHINode *PN = cast<PHINode>(I);
1015  if (!canEvaluateZExtd(PN->getIncomingValue(0), Ty, BitsToClear, IC, CxtI))
1016  return false;
1017  for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i)
1018  if (!canEvaluateZExtd(PN->getIncomingValue(i), Ty, Tmp, IC, CxtI) ||
1019  // TODO: If important, we could handle the case when the BitsToClear
1020  // are known zero in the disagreeing input.
1021  Tmp != BitsToClear)
1022  return false;
1023  return true;
1024  }
1025  default:
1026  // TODO: Can handle more cases here.
1027  return false;
1028  }
1029 }
1030 
1032  // If this zero extend is only used by a truncate, let the truncate be
1033  // eliminated before we try to optimize this zext.
1034  if (CI.hasOneUse() && isa<TruncInst>(CI.user_back()))
1035  return nullptr;
1036 
1037  // If one of the common conversion will work, do it.
1038  if (Instruction *Result = commonCastTransforms(CI))
1039  return Result;
1040 
1041  Value *Src = CI.getOperand(0);
1042  Type *SrcTy = Src->getType(), *DestTy = CI.getType();
1043 
1044  // Attempt to extend the entire input expression tree to the destination
1045  // type. Only do this if the dest type is a simple type, don't convert the
1046  // expression tree to something weird like i93 unless the source is also
1047  // strange.
1048  unsigned BitsToClear;
1049  if ((DestTy->isVectorTy() || shouldChangeType(SrcTy, DestTy)) &&
1050  canEvaluateZExtd(Src, DestTy, BitsToClear, *this, &CI)) {
1051  assert(BitsToClear <= SrcTy->getScalarSizeInBits() &&
1052  "Can't clear more bits than in SrcTy");
1053 
1054  // Okay, we can transform this! Insert the new expression now.
1055  DEBUG(dbgs() << "ICE: EvaluateInDifferentType converting expression type"
1056  " to avoid zero extend: " << CI << '\n');
1057  Value *Res = EvaluateInDifferentType(Src, DestTy, false);
1058  assert(Res->getType() == DestTy);
1059 
1060  uint32_t SrcBitsKept = SrcTy->getScalarSizeInBits()-BitsToClear;
1061  uint32_t DestBitSize = DestTy->getScalarSizeInBits();
1062 
1063  // If the high bits are already filled with zeros, just replace this
1064  // cast with the result.
1065  if (MaskedValueIsZero(Res,
1066  APInt::getHighBitsSet(DestBitSize,
1067  DestBitSize-SrcBitsKept),
1068  0, &CI))
1069  return replaceInstUsesWith(CI, Res);
1070 
1071  // We need to emit an AND to clear the high bits.
1072  Constant *C = ConstantInt::get(Res->getType(),
1073  APInt::getLowBitsSet(DestBitSize, SrcBitsKept));
1074  return BinaryOperator::CreateAnd(Res, C);
1075  }
1076 
1077  // If this is a TRUNC followed by a ZEXT then we are dealing with integral
1078  // types and if the sizes are just right we can convert this into a logical
1079  // 'and' which will be much cheaper than the pair of casts.
1080  if (TruncInst *CSrc = dyn_cast<TruncInst>(Src)) { // A->B->C cast
1081  // TODO: Subsume this into EvaluateInDifferentType.
1082 
1083  // Get the sizes of the types involved. We know that the intermediate type
1084  // will be smaller than A or C, but don't know the relation between A and C.
1085  Value *A = CSrc->getOperand(0);
1086  unsigned SrcSize = A->getType()->getScalarSizeInBits();
1087  unsigned MidSize = CSrc->getType()->getScalarSizeInBits();
1088  unsigned DstSize = CI.getType()->getScalarSizeInBits();
1089  // If we're actually extending zero bits, then if
1090  // SrcSize < DstSize: zext(a & mask)
1091  // SrcSize == DstSize: a & mask
1092  // SrcSize > DstSize: trunc(a) & mask
1093  if (SrcSize < DstSize) {
1094  APInt AndValue(APInt::getLowBitsSet(SrcSize, MidSize));
1095  Constant *AndConst = ConstantInt::get(A->getType(), AndValue);
1096  Value *And = Builder.CreateAnd(A, AndConst, CSrc->getName() + ".mask");
1097  return new ZExtInst(And, CI.getType());
1098  }
1099 
1100  if (SrcSize == DstSize) {
1101  APInt AndValue(APInt::getLowBitsSet(SrcSize, MidSize));
1102  return BinaryOperator::CreateAnd(A, ConstantInt::get(A->getType(),
1103  AndValue));
1104  }
1105  if (SrcSize > DstSize) {
1106  Value *Trunc = Builder.CreateTrunc(A, CI.getType());
1107  APInt AndValue(APInt::getLowBitsSet(DstSize, MidSize));
1108  return BinaryOperator::CreateAnd(Trunc,
1109  ConstantInt::get(Trunc->getType(),
1110  AndValue));
1111  }
1112  }
1113 
1114  if (ICmpInst *ICI = dyn_cast<ICmpInst>(Src))
1115  return transformZExtICmp(ICI, CI);
1116 
1117  BinaryOperator *SrcI = dyn_cast<BinaryOperator>(Src);
1118  if (SrcI && SrcI->getOpcode() == Instruction::Or) {
1119  // zext (or icmp, icmp) -> or (zext icmp), (zext icmp) if at least one
1120  // of the (zext icmp) can be eliminated. If so, immediately perform the
1121  // according elimination.
1122  ICmpInst *LHS = dyn_cast<ICmpInst>(SrcI->getOperand(0));
1123  ICmpInst *RHS = dyn_cast<ICmpInst>(SrcI->getOperand(1));
1124  if (LHS && RHS && LHS->hasOneUse() && RHS->hasOneUse() &&
1125  (transformZExtICmp(LHS, CI, false) ||
1126  transformZExtICmp(RHS, CI, false))) {
1127  // zext (or icmp, icmp) -> or (zext icmp), (zext icmp)
1128  Value *LCast = Builder.CreateZExt(LHS, CI.getType(), LHS->getName());
1129  Value *RCast = Builder.CreateZExt(RHS, CI.getType(), RHS->getName());
1130  BinaryOperator *Or = BinaryOperator::Create(Instruction::Or, LCast, RCast);
1131 
1132  // Perform the elimination.
1133  if (auto *LZExt = dyn_cast<ZExtInst>(LCast))
1134  transformZExtICmp(LHS, *LZExt);
1135  if (auto *RZExt = dyn_cast<ZExtInst>(RCast))
1136  transformZExtICmp(RHS, *RZExt);
1137 
1138  return Or;
1139  }
1140  }
1141 
1142  // zext(trunc(X) & C) -> (X & zext(C)).
1143  Constant *C;
1144  Value *X;
1145  if (SrcI &&
1146  match(SrcI, m_OneUse(m_And(m_Trunc(m_Value(X)), m_Constant(C)))) &&
1147  X->getType() == CI.getType())
1148  return BinaryOperator::CreateAnd(X, ConstantExpr::getZExt(C, CI.getType()));
1149 
1150  // zext((trunc(X) & C) ^ C) -> ((X & zext(C)) ^ zext(C)).
1151  Value *And;
1152  if (SrcI && match(SrcI, m_OneUse(m_Xor(m_Value(And), m_Constant(C)))) &&
1153  match(And, m_OneUse(m_And(m_Trunc(m_Value(X)), m_Specific(C)))) &&
1154  X->getType() == CI.getType()) {
1155  Constant *ZC = ConstantExpr::getZExt(C, CI.getType());
1156  return BinaryOperator::CreateXor(Builder.CreateAnd(X, ZC), ZC);
1157  }
1158 
1159  return nullptr;
1160 }
1161 
1162 /// Transform (sext icmp) to bitwise / integer operations to eliminate the icmp.
1163 Instruction *InstCombiner::transformSExtICmp(ICmpInst *ICI, Instruction &CI) {
1164  Value *Op0 = ICI->getOperand(0), *Op1 = ICI->getOperand(1);
1165  ICmpInst::Predicate Pred = ICI->getPredicate();
1166 
1167  // Don't bother if Op1 isn't of vector or integer type.
1168  if (!Op1->getType()->isIntOrIntVectorTy())
1169  return nullptr;
1170 
1171  if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
1172  // (x <s 0) ? -1 : 0 -> ashr x, 31 -> all ones if negative
1173  // (x >s -1) ? -1 : 0 -> not (ashr x, 31) -> all ones if positive
1174  if ((Pred == ICmpInst::ICMP_SLT && Op1C->isNullValue()) ||
1175  (Pred == ICmpInst::ICMP_SGT && Op1C->isAllOnesValue())) {
1176 
1177  Value *Sh = ConstantInt::get(Op0->getType(),
1178  Op0->getType()->getScalarSizeInBits()-1);
1179  Value *In = Builder.CreateAShr(Op0, Sh, Op0->getName() + ".lobit");
1180  if (In->getType() != CI.getType())
1181  In = Builder.CreateIntCast(In, CI.getType(), true /*SExt*/);
1182 
1183  if (Pred == ICmpInst::ICMP_SGT)
1184  In = Builder.CreateNot(In, In->getName() + ".not");
1185  return replaceInstUsesWith(CI, In);
1186  }
1187  }
1188 
1189  if (ConstantInt *Op1C = dyn_cast<ConstantInt>(Op1)) {
1190  // If we know that only one bit of the LHS of the icmp can be set and we
1191  // have an equality comparison with zero or a power of 2, we can transform
1192  // the icmp and sext into bitwise/integer operations.
1193  if (ICI->hasOneUse() &&
1194  ICI->isEquality() && (Op1C->isZero() || Op1C->getValue().isPowerOf2())){
1195  KnownBits Known = computeKnownBits(Op0, 0, &CI);
1196 
1197  APInt KnownZeroMask(~Known.Zero);
1198  if (KnownZeroMask.isPowerOf2()) {
1199  Value *In = ICI->getOperand(0);
1200 
1201  // If the icmp tests for a known zero bit we can constant fold it.
1202  if (!Op1C->isZero() && Op1C->getValue() != KnownZeroMask) {
1203  Value *V = Pred == ICmpInst::ICMP_NE ?
1206  return replaceInstUsesWith(CI, V);
1207  }
1208 
1209  if (!Op1C->isZero() == (Pred == ICmpInst::ICMP_NE)) {
1210  // sext ((x & 2^n) == 0) -> (x >> n) - 1
1211  // sext ((x & 2^n) != 2^n) -> (x >> n) - 1
1212  unsigned ShiftAmt = KnownZeroMask.countTrailingZeros();
1213  // Perform a right shift to place the desired bit in the LSB.
1214  if (ShiftAmt)
1215  In = Builder.CreateLShr(In,
1216  ConstantInt::get(In->getType(), ShiftAmt));
1217 
1218  // At this point "In" is either 1 or 0. Subtract 1 to turn
1219  // {1, 0} -> {0, -1}.
1220  In = Builder.CreateAdd(In,
1222  "sext");
1223  } else {
1224  // sext ((x & 2^n) != 0) -> (x << bitwidth-n) a>> bitwidth-1
1225  // sext ((x & 2^n) == 2^n) -> (x << bitwidth-n) a>> bitwidth-1
1226  unsigned ShiftAmt = KnownZeroMask.countLeadingZeros();
1227  // Perform a left shift to place the desired bit in the MSB.
1228  if (ShiftAmt)
1229  In = Builder.CreateShl(In,
1230  ConstantInt::get(In->getType(), ShiftAmt));
1231 
1232  // Distribute the bit over the whole bit width.
1233  In = Builder.CreateAShr(In, ConstantInt::get(In->getType(),
1234  KnownZeroMask.getBitWidth() - 1), "sext");
1235  }
1236 
1237  if (CI.getType() == In->getType())
1238  return replaceInstUsesWith(CI, In);
1239  return CastInst::CreateIntegerCast(In, CI.getType(), true/*SExt*/);
1240  }
1241  }
1242  }
1243 
1244  return nullptr;
1245 }
1246 
1247 /// Return true if we can take the specified value and return it as type Ty
1248 /// without inserting any new casts and without changing the value of the common
1249 /// low bits. This is used by code that tries to promote integer operations to
1250 /// a wider types will allow us to eliminate the extension.
1251 ///
1252 /// This function works on both vectors and scalars.
1253 ///
1254 static bool canEvaluateSExtd(Value *V, Type *Ty) {
1256  "Can't sign extend type to a smaller type");
1257  // If this is a constant, it can be trivially promoted.
1258  if (isa<Constant>(V))
1259  return true;
1260 
1262  if (!I) return false;
1263 
1264  // If this is a truncate from the dest type, we can trivially eliminate it.
1265  if (isa<TruncInst>(I) && I->getOperand(0)->getType() == Ty)
1266  return true;
1267 
1268  // We can't extend or shrink something that has multiple uses: doing so would
1269  // require duplicating the instruction in general, which isn't profitable.
1270  if (!I->hasOneUse()) return false;
1271 
1272  switch (I->getOpcode()) {
1273  case Instruction::SExt: // sext(sext(x)) -> sext(x)
1274  case Instruction::ZExt: // sext(zext(x)) -> zext(x)
1275  case Instruction::Trunc: // sext(trunc(x)) -> trunc(x) or sext(x)
1276  return true;
1277  case Instruction::And:
1278  case Instruction::Or:
1279  case Instruction::Xor:
1280  case Instruction::Add:
1281  case Instruction::Sub:
1282  case Instruction::Mul:
1283  // These operators can all arbitrarily be extended if their inputs can.
1284  return canEvaluateSExtd(I->getOperand(0), Ty) &&
1285  canEvaluateSExtd(I->getOperand(1), Ty);
1286 
1287  //case Instruction::Shl: TODO
1288  //case Instruction::LShr: TODO
1289 
1290  case Instruction::Select:
1291  return canEvaluateSExtd(I->getOperand(1), Ty) &&
1292  canEvaluateSExtd(I->getOperand(2), Ty);
1293 
1294  case Instruction::PHI: {
1295  // We can change a phi if we can change all operands. Note that we never
1296  // get into trouble with cyclic PHIs here because we only consider
1297  // instructions with a single use.
1298  PHINode *PN = cast<PHINode>(I);
1299  for (Value *IncValue : PN->incoming_values())
1300  if (!canEvaluateSExtd(IncValue, Ty)) return false;
1301  return true;
1302  }
1303  default:
1304  // TODO: Can handle more cases here.
1305  break;
1306  }
1307 
1308  return false;
1309 }
1310 
1312  // If this sign extend is only used by a truncate, let the truncate be
1313  // eliminated before we try to optimize this sext.
1314  if (CI.hasOneUse() && isa<TruncInst>(CI.user_back()))
1315  return nullptr;
1316 
1317  if (Instruction *I = commonCastTransforms(CI))
1318  return I;
1319 
1320  Value *Src = CI.getOperand(0);
1321  Type *SrcTy = Src->getType(), *DestTy = CI.getType();
1322 
1323  // If we know that the value being extended is positive, we can use a zext
1324  // instead.
1325  KnownBits Known = computeKnownBits(Src, 0, &CI);
1326  if (Known.isNonNegative()) {
1327  Value *ZExt = Builder.CreateZExt(Src, DestTy);
1328  return replaceInstUsesWith(CI, ZExt);
1329  }
1330 
1331  // Attempt to extend the entire input expression tree to the destination
1332  // type. Only do this if the dest type is a simple type, don't convert the
1333  // expression tree to something weird like i93 unless the source is also
1334  // strange.
1335  if ((DestTy->isVectorTy() || shouldChangeType(SrcTy, DestTy)) &&
1336  canEvaluateSExtd(Src, DestTy)) {
1337  // Okay, we can transform this! Insert the new expression now.
1338  DEBUG(dbgs() << "ICE: EvaluateInDifferentType converting expression type"
1339  " to avoid sign extend: " << CI << '\n');
1340  Value *Res = EvaluateInDifferentType(Src, DestTy, true);
1341  assert(Res->getType() == DestTy);
1342 
1343  uint32_t SrcBitSize = SrcTy->getScalarSizeInBits();
1344  uint32_t DestBitSize = DestTy->getScalarSizeInBits();
1345 
1346  // If the high bits are already filled with sign bit, just replace this
1347  // cast with the result.
1348  if (ComputeNumSignBits(Res, 0, &CI) > DestBitSize - SrcBitSize)
1349  return replaceInstUsesWith(CI, Res);
1350 
1351  // We need to emit a shl + ashr to do the sign extend.
1352  Value *ShAmt = ConstantInt::get(DestTy, DestBitSize-SrcBitSize);
1353  return BinaryOperator::CreateAShr(Builder.CreateShl(Res, ShAmt, "sext"),
1354  ShAmt);
1355  }
1356 
1357  // If the input is a trunc from the destination type, then turn sext(trunc(x))
1358  // into shifts.
1359  Value *X;
1360  if (match(Src, m_OneUse(m_Trunc(m_Value(X)))) && X->getType() == DestTy) {
1361  // sext(trunc(X)) --> ashr(shl(X, C), C)
1362  unsigned SrcBitSize = SrcTy->getScalarSizeInBits();
1363  unsigned DestBitSize = DestTy->getScalarSizeInBits();
1364  Constant *ShAmt = ConstantInt::get(DestTy, DestBitSize - SrcBitSize);
1365  return BinaryOperator::CreateAShr(Builder.CreateShl(X, ShAmt), ShAmt);
1366  }
1367 
1368  if (ICmpInst *ICI = dyn_cast<ICmpInst>(Src))
1369  return transformSExtICmp(ICI, CI);
1370 
1371  // If the input is a shl/ashr pair of a same constant, then this is a sign
1372  // extension from a smaller value. If we could trust arbitrary bitwidth
1373  // integers, we could turn this into a truncate to the smaller bit and then
1374  // use a sext for the whole extension. Since we don't, look deeper and check
1375  // for a truncate. If the source and dest are the same type, eliminate the
1376  // trunc and extend and just do shifts. For example, turn:
1377  // %a = trunc i32 %i to i8
1378  // %b = shl i8 %a, 6
1379  // %c = ashr i8 %b, 6
1380  // %d = sext i8 %c to i32
1381  // into:
1382  // %a = shl i32 %i, 30
1383  // %d = ashr i32 %a, 30
1384  Value *A = nullptr;
1385  // TODO: Eventually this could be subsumed by EvaluateInDifferentType.
1386  ConstantInt *BA = nullptr, *CA = nullptr;
1387  if (match(Src, m_AShr(m_Shl(m_Trunc(m_Value(A)), m_ConstantInt(BA)),
1388  m_ConstantInt(CA))) &&
1389  BA == CA && A->getType() == CI.getType()) {
1390  unsigned MidSize = Src->getType()->getScalarSizeInBits();
1391  unsigned SrcDstSize = CI.getType()->getScalarSizeInBits();
1392  unsigned ShAmt = CA->getZExtValue()+SrcDstSize-MidSize;
1393  Constant *ShAmtV = ConstantInt::get(CI.getType(), ShAmt);
1394  A = Builder.CreateShl(A, ShAmtV, CI.getName());
1395  return BinaryOperator::CreateAShr(A, ShAmtV);
1396  }
1397 
1398  return nullptr;
1399 }
1400 
1401 
1402 /// Return a Constant* for the specified floating-point constant if it fits
1403 /// in the specified FP type without changing its value.
1404 static Constant *fitsInFPType(ConstantFP *CFP, const fltSemantics &Sem) {
1405  bool losesInfo;
1406  APFloat F = CFP->getValueAPF();
1407  (void)F.convert(Sem, APFloat::rmNearestTiesToEven, &losesInfo);
1408  if (!losesInfo)
1409  return ConstantFP::get(CFP->getContext(), F);
1410  return nullptr;
1411 }
1412 
1413 /// Look through floating-point extensions until we get the source value.
1415  while (auto *FPExt = dyn_cast<FPExtInst>(V))
1416  V = FPExt->getOperand(0);
1417 
1418  // If this value is a constant, return the constant in the smallest FP type
1419  // that can accurately represent it. This allows us to turn
1420  // (float)((double)X+2.0) into x+2.0f.
1421  if (auto *CFP = dyn_cast<ConstantFP>(V)) {
1422  if (CFP->getType() == Type::getPPC_FP128Ty(V->getContext()))
1423  return V; // No constant folding of this.
1424  // See if the value can be truncated to half and then reextended.
1425  if (Value *V = fitsInFPType(CFP, APFloat::IEEEhalf()))
1426  return V;
1427  // See if the value can be truncated to float and then reextended.
1428  if (Value *V = fitsInFPType(CFP, APFloat::IEEEsingle()))
1429  return V;
1430  if (CFP->getType()->isDoubleTy())
1431  return V; // Won't shrink.
1432  if (Value *V = fitsInFPType(CFP, APFloat::IEEEdouble()))
1433  return V;
1434  // Don't try to shrink to various long double types.
1435  }
1436 
1437  return V;
1438 }
1439 
1441  if (Instruction *I = commonCastTransforms(CI))
1442  return I;
1443  // If we have fptrunc(OpI (fpextend x), (fpextend y)), we would like to
1444  // simplify this expression to avoid one or more of the trunc/extend
1445  // operations if we can do so without changing the numerical results.
1446  //
1447  // The exact manner in which the widths of the operands interact to limit
1448  // what we can and cannot do safely varies from operation to operation, and
1449  // is explained below in the various case statements.
1451  if (OpI && OpI->hasOneUse()) {
1452  Value *LHSOrig = lookThroughFPExtensions(OpI->getOperand(0));
1453  Value *RHSOrig = lookThroughFPExtensions(OpI->getOperand(1));
1454  unsigned OpWidth = OpI->getType()->getFPMantissaWidth();
1455  unsigned LHSWidth = LHSOrig->getType()->getFPMantissaWidth();
1456  unsigned RHSWidth = RHSOrig->getType()->getFPMantissaWidth();
1457  unsigned SrcWidth = std::max(LHSWidth, RHSWidth);
1458  unsigned DstWidth = CI.getType()->getFPMantissaWidth();
1459  switch (OpI->getOpcode()) {
1460  default: break;
1461  case Instruction::FAdd:
1462  case Instruction::FSub:
1463  // For addition and subtraction, the infinitely precise result can
1464  // essentially be arbitrarily wide; proving that double rounding
1465  // will not occur because the result of OpI is exact (as we will for
1466  // FMul, for example) is hopeless. However, we *can* nonetheless
1467  // frequently know that double rounding cannot occur (or that it is
1468  // innocuous) by taking advantage of the specific structure of
1469  // infinitely-precise results that admit double rounding.
1470  //
1471  // Specifically, if OpWidth >= 2*DstWdith+1 and DstWidth is sufficient
1472  // to represent both sources, we can guarantee that the double
1473  // rounding is innocuous (See p50 of Figueroa's 2000 PhD thesis,
1474  // "A Rigorous Framework for Fully Supporting the IEEE Standard ..."
1475  // for proof of this fact).
1476  //
1477  // Note: Figueroa does not consider the case where DstFormat !=
1478  // SrcFormat. It's possible (likely even!) that this analysis
1479  // could be tightened for those cases, but they are rare (the main
1480  // case of interest here is (float)((double)float + float)).
1481  if (OpWidth >= 2*DstWidth+1 && DstWidth >= SrcWidth) {
1482  if (LHSOrig->getType() != CI.getType())
1483  LHSOrig = Builder.CreateFPExt(LHSOrig, CI.getType());
1484  if (RHSOrig->getType() != CI.getType())
1485  RHSOrig = Builder.CreateFPExt(RHSOrig, CI.getType());
1486  Instruction *RI =
1487  BinaryOperator::Create(OpI->getOpcode(), LHSOrig, RHSOrig);
1488  RI->copyFastMathFlags(OpI);
1489  return RI;
1490  }
1491  break;
1492  case Instruction::FMul:
1493  // For multiplication, the infinitely precise result has at most
1494  // LHSWidth + RHSWidth significant bits; if OpWidth is sufficient
1495  // that such a value can be exactly represented, then no double
1496  // rounding can possibly occur; we can safely perform the operation
1497  // in the destination format if it can represent both sources.
1498  if (OpWidth >= LHSWidth + RHSWidth && DstWidth >= SrcWidth) {
1499  if (LHSOrig->getType() != CI.getType())
1500  LHSOrig = Builder.CreateFPExt(LHSOrig, CI.getType());
1501  if (RHSOrig->getType() != CI.getType())
1502  RHSOrig = Builder.CreateFPExt(RHSOrig, CI.getType());
1503  Instruction *RI =
1504  BinaryOperator::CreateFMul(LHSOrig, RHSOrig);
1505  RI->copyFastMathFlags(OpI);
1506  return RI;
1507  }
1508  break;
1509  case Instruction::FDiv:
1510  // For division, we use again use the bound from Figueroa's
1511  // dissertation. I am entirely certain that this bound can be
1512  // tightened in the unbalanced operand case by an analysis based on
1513  // the diophantine rational approximation bound, but the well-known
1514  // condition used here is a good conservative first pass.
1515  // TODO: Tighten bound via rigorous analysis of the unbalanced case.
1516  if (OpWidth >= 2*DstWidth && DstWidth >= SrcWidth) {
1517  if (LHSOrig->getType() != CI.getType())
1518  LHSOrig = Builder.CreateFPExt(LHSOrig, CI.getType());
1519  if (RHSOrig->getType() != CI.getType())
1520  RHSOrig = Builder.CreateFPExt(RHSOrig, CI.getType());
1521  Instruction *RI =
1522  BinaryOperator::CreateFDiv(LHSOrig, RHSOrig);
1523  RI->copyFastMathFlags(OpI);
1524  return RI;
1525  }
1526  break;
1527  case Instruction::FRem:
1528  // Remainder is straightforward. Remainder is always exact, so the
1529  // type of OpI doesn't enter into things at all. We simply evaluate
1530  // in whichever source type is larger, then convert to the
1531  // destination type.
1532  if (SrcWidth == OpWidth)
1533  break;
1534  if (LHSWidth < SrcWidth)
1535  LHSOrig = Builder.CreateFPExt(LHSOrig, RHSOrig->getType());
1536  else if (RHSWidth <= SrcWidth)
1537  RHSOrig = Builder.CreateFPExt(RHSOrig, LHSOrig->getType());
1538  if (LHSOrig != OpI->getOperand(0) || RHSOrig != OpI->getOperand(1)) {
1539  Value *ExactResult = Builder.CreateFRem(LHSOrig, RHSOrig);
1540  if (Instruction *RI = dyn_cast<Instruction>(ExactResult))
1541  RI->copyFastMathFlags(OpI);
1542  return CastInst::CreateFPCast(ExactResult, CI.getType());
1543  }
1544  }
1545 
1546  // (fptrunc (fneg x)) -> (fneg (fptrunc x))
1547  if (BinaryOperator::isFNeg(OpI)) {
1548  Value *InnerTrunc = Builder.CreateFPTrunc(OpI->getOperand(1),
1549  CI.getType());
1550  Instruction *RI = BinaryOperator::CreateFNeg(InnerTrunc);
1551  RI->copyFastMathFlags(OpI);
1552  return RI;
1553  }
1554  }
1555 
1556  // (fptrunc (select cond, R1, Cst)) -->
1557  // (select cond, (fptrunc R1), (fptrunc Cst))
1558  //
1559  // - but only if this isn't part of a min/max operation, else we'll
1560  // ruin min/max canonical form which is to have the select and
1561  // compare's operands be of the same type with no casts to look through.
1562  Value *LHS, *RHS;
1564  if (SI &&
1565  (isa<ConstantFP>(SI->getOperand(1)) ||
1566  isa<ConstantFP>(SI->getOperand(2))) &&
1567  matchSelectPattern(SI, LHS, RHS).Flavor == SPF_UNKNOWN) {
1568  Value *LHSTrunc = Builder.CreateFPTrunc(SI->getOperand(1), CI.getType());
1569  Value *RHSTrunc = Builder.CreateFPTrunc(SI->getOperand(2), CI.getType());
1570  return SelectInst::Create(SI->getOperand(0), LHSTrunc, RHSTrunc);
1571  }
1572 
1574  if (II) {
1575  switch (II->getIntrinsicID()) {
1576  default: break;
1577  case Intrinsic::fabs:
1578  case Intrinsic::ceil:
1579  case Intrinsic::floor:
1580  case Intrinsic::rint:
1581  case Intrinsic::round:
1582  case Intrinsic::nearbyint:
1583  case Intrinsic::trunc: {
1584  Value *Src = II->getArgOperand(0);
1585  if (!Src->hasOneUse())
1586  break;
1587 
1588  // Except for fabs, this transformation requires the input of the unary FP
1589  // operation to be itself an fpext from the type to which we're
1590  // truncating.
1591  if (II->getIntrinsicID() != Intrinsic::fabs) {
1592  FPExtInst *FPExtSrc = dyn_cast<FPExtInst>(Src);
1593  if (!FPExtSrc || FPExtSrc->getOperand(0)->getType() != CI.getType())
1594  break;
1595  }
1596 
1597  // Do unary FP operation on smaller type.
1598  // (fptrunc (fabs x)) -> (fabs (fptrunc x))
1599  Value *InnerTrunc = Builder.CreateFPTrunc(Src, CI.getType());
1600  Type *IntrinsicType[] = { CI.getType() };
1601  Function *Overload = Intrinsic::getDeclaration(
1602  CI.getModule(), II->getIntrinsicID(), IntrinsicType);
1603 
1605  II->getOperandBundlesAsDefs(OpBundles);
1606 
1607  Value *Args[] = { InnerTrunc };
1608  CallInst *NewCI = CallInst::Create(Overload, Args,
1609  OpBundles, II->getName());
1610  NewCI->copyFastMathFlags(II);
1611  return NewCI;
1612  }
1613  }
1614  }
1615 
1616  if (Instruction *I = shrinkInsertElt(CI, Builder))
1617  return I;
1618 
1619  return nullptr;
1620 }
1621 
1623  return commonCastTransforms(CI);
1624 }
1625 
1626 // fpto{s/u}i({u/s}itofp(X)) --> X or zext(X) or sext(X) or trunc(X)
1627 // This is safe if the intermediate type has enough bits in its mantissa to
1628 // accurately represent all values of X. For example, this won't work with
1629 // i64 -> float -> i64.
1631  if (!isa<UIToFPInst>(FI.getOperand(0)) && !isa<SIToFPInst>(FI.getOperand(0)))
1632  return nullptr;
1633  Instruction *OpI = cast<Instruction>(FI.getOperand(0));
1634 
1635  Value *SrcI = OpI->getOperand(0);
1636  Type *FITy = FI.getType();
1637  Type *OpITy = OpI->getType();
1638  Type *SrcTy = SrcI->getType();
1639  bool IsInputSigned = isa<SIToFPInst>(OpI);
1640  bool IsOutputSigned = isa<FPToSIInst>(FI);
1641 
1642  // We can safely assume the conversion won't overflow the output range,
1643  // because (for example) (uint8_t)18293.f is undefined behavior.
1644 
1645  // Since we can assume the conversion won't overflow, our decision as to
1646  // whether the input will fit in the float should depend on the minimum
1647  // of the input range and output range.
1648 
1649  // This means this is also safe for a signed input and unsigned output, since
1650  // a negative input would lead to undefined behavior.
1651  int InputSize = (int)SrcTy->getScalarSizeInBits() - IsInputSigned;
1652  int OutputSize = (int)FITy->getScalarSizeInBits() - IsOutputSigned;
1653  int ActualSize = std::min(InputSize, OutputSize);
1654 
1655  if (ActualSize <= OpITy->getFPMantissaWidth()) {
1656  if (FITy->getScalarSizeInBits() > SrcTy->getScalarSizeInBits()) {
1657  if (IsInputSigned && IsOutputSigned)
1658  return new SExtInst(SrcI, FITy);
1659  return new ZExtInst(SrcI, FITy);
1660  }
1661  if (FITy->getScalarSizeInBits() < SrcTy->getScalarSizeInBits())
1662  return new TruncInst(SrcI, FITy);
1663  if (SrcTy == FITy)
1664  return replaceInstUsesWith(FI, SrcI);
1665  return new BitCastInst(SrcI, FITy);
1666  }
1667  return nullptr;
1668 }
1669 
1671  Instruction *OpI = dyn_cast<Instruction>(FI.getOperand(0));
1672  if (!OpI)
1673  return commonCastTransforms(FI);
1674 
1675  if (Instruction *I = FoldItoFPtoI(FI))
1676  return I;
1677 
1678  return commonCastTransforms(FI);
1679 }
1680 
1682  Instruction *OpI = dyn_cast<Instruction>(FI.getOperand(0));
1683  if (!OpI)
1684  return commonCastTransforms(FI);
1685 
1686  if (Instruction *I = FoldItoFPtoI(FI))
1687  return I;
1688 
1689  return commonCastTransforms(FI);
1690 }
1691 
1693  return commonCastTransforms(CI);
1694 }
1695 
1697  return commonCastTransforms(CI);
1698 }
1699 
1701  // If the source integer type is not the intptr_t type for this target, do a
1702  // trunc or zext to the intptr_t type, then inttoptr of it. This allows the
1703  // cast to be exposed to other transforms.
1704  unsigned AS = CI.getAddressSpace();
1705  if (CI.getOperand(0)->getType()->getScalarSizeInBits() !=
1706  DL.getPointerSizeInBits(AS)) {
1707  Type *Ty = DL.getIntPtrType(CI.getContext(), AS);
1708  if (CI.getType()->isVectorTy()) // Handle vectors of pointers.
1709  Ty = VectorType::get(Ty, CI.getType()->getVectorNumElements());
1710 
1711  Value *P = Builder.CreateZExtOrTrunc(CI.getOperand(0), Ty);
1712  return new IntToPtrInst(P, CI.getType());
1713  }
1714 
1715  if (Instruction *I = commonCastTransforms(CI))
1716  return I;
1717 
1718  return nullptr;
1719 }
1720 
1721 /// @brief Implement the transforms for cast of pointer (bitcast/ptrtoint)
1723  Value *Src = CI.getOperand(0);
1724 
1725  if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Src)) {
1726  // If casting the result of a getelementptr instruction with no offset, turn
1727  // this into a cast of the original pointer!
1728  if (GEP->hasAllZeroIndices() &&
1729  // If CI is an addrspacecast and GEP changes the poiner type, merging
1730  // GEP into CI would undo canonicalizing addrspacecast with different
1731  // pointer types, causing infinite loops.
1732  (!isa<AddrSpaceCastInst>(CI) ||
1733  GEP->getType() == GEP->getPointerOperandType())) {
1734  // Changing the cast operand is usually not a good idea but it is safe
1735  // here because the pointer operand is being replaced with another
1736  // pointer operand so the opcode doesn't need to change.
1737  Worklist.Add(GEP);
1738  CI.setOperand(0, GEP->getOperand(0));
1739  return &CI;
1740  }
1741  }
1742 
1743  return commonCastTransforms(CI);
1744 }
1745 
1747  // If the destination integer type is not the intptr_t type for this target,
1748  // do a ptrtoint to intptr_t then do a trunc or zext. This allows the cast
1749  // to be exposed to other transforms.
1750 
1751  Type *Ty = CI.getType();
1752  unsigned AS = CI.getPointerAddressSpace();
1753 
1754  if (Ty->getScalarSizeInBits() == DL.getPointerSizeInBits(AS))
1755  return commonPointerCastTransforms(CI);
1756 
1757  Type *PtrTy = DL.getIntPtrType(CI.getContext(), AS);
1758  if (Ty->isVectorTy()) // Handle vectors of pointers.
1759  PtrTy = VectorType::get(PtrTy, Ty->getVectorNumElements());
1760 
1761  Value *P = Builder.CreatePtrToInt(CI.getOperand(0), PtrTy);
1762  return CastInst::CreateIntegerCast(P, Ty, /*isSigned=*/false);
1763 }
1764 
1765 /// This input value (which is known to have vector type) is being zero extended
1766 /// or truncated to the specified vector type.
1767 /// Try to replace it with a shuffle (and vector/vector bitcast) if possible.
1768 ///
1769 /// The source and destination vector types may have different element types.
1771  InstCombiner &IC) {
1772  // We can only do this optimization if the output is a multiple of the input
1773  // element size, or the input is a multiple of the output element size.
1774  // Convert the input type to have the same element type as the output.
1775  VectorType *SrcTy = cast<VectorType>(InVal->getType());
1776 
1777  if (SrcTy->getElementType() != DestTy->getElementType()) {
1778  // The input types don't need to be identical, but for now they must be the
1779  // same size. There is no specific reason we couldn't handle things like
1780  // <4 x i16> -> <4 x i32> by bitcasting to <2 x i32> but haven't gotten
1781  // there yet.
1782  if (SrcTy->getElementType()->getPrimitiveSizeInBits() !=
1784  return nullptr;
1785 
1786  SrcTy = VectorType::get(DestTy->getElementType(), SrcTy->getNumElements());
1787  InVal = IC.Builder.CreateBitCast(InVal, SrcTy);
1788  }
1789 
1790  // Now that the element types match, get the shuffle mask and RHS of the
1791  // shuffle to use, which depends on whether we're increasing or decreasing the
1792  // size of the input.
1793  SmallVector<uint32_t, 16> ShuffleMask;
1794  Value *V2;
1795 
1796  if (SrcTy->getNumElements() > DestTy->getNumElements()) {
1797  // If we're shrinking the number of elements, just shuffle in the low
1798  // elements from the input and use undef as the second shuffle input.
1799  V2 = UndefValue::get(SrcTy);
1800  for (unsigned i = 0, e = DestTy->getNumElements(); i != e; ++i)
1801  ShuffleMask.push_back(i);
1802 
1803  } else {
1804  // If we're increasing the number of elements, shuffle in all of the
1805  // elements from InVal and fill the rest of the result elements with zeros
1806  // from a constant zero.
1807  V2 = Constant::getNullValue(SrcTy);
1808  unsigned SrcElts = SrcTy->getNumElements();
1809  for (unsigned i = 0, e = SrcElts; i != e; ++i)
1810  ShuffleMask.push_back(i);
1811 
1812  // The excess elements reference the first element of the zero input.
1813  for (unsigned i = 0, e = DestTy->getNumElements()-SrcElts; i != e; ++i)
1814  ShuffleMask.push_back(SrcElts);
1815  }
1816 
1817  return new ShuffleVectorInst(InVal, V2,
1819  ShuffleMask));
1820 }
1821 
1822 static bool isMultipleOfTypeSize(unsigned Value, Type *Ty) {
1823  return Value % Ty->getPrimitiveSizeInBits() == 0;
1824 }
1825 
1826 static unsigned getTypeSizeIndex(unsigned Value, Type *Ty) {
1827  return Value / Ty->getPrimitiveSizeInBits();
1828 }
1829 
1830 /// V is a value which is inserted into a vector of VecEltTy.
1831 /// Look through the value to see if we can decompose it into
1832 /// insertions into the vector. See the example in the comment for
1833 /// OptimizeIntegerToVectorInsertions for the pattern this handles.
1834 /// The type of V is always a non-zero multiple of VecEltTy's size.
1835 /// Shift is the number of bits between the lsb of V and the lsb of
1836 /// the vector.
1837 ///
1838 /// This returns false if the pattern can't be matched or true if it can,
1839 /// filling in Elements with the elements found here.
1840 static bool collectInsertionElements(Value *V, unsigned Shift,
1841  SmallVectorImpl<Value *> &Elements,
1842  Type *VecEltTy, bool isBigEndian) {
1843  assert(isMultipleOfTypeSize(Shift, VecEltTy) &&
1844  "Shift should be a multiple of the element type size");
1845 
1846  // Undef values never contribute useful bits to the result.
1847  if (isa<UndefValue>(V)) return true;
1848 
1849  // If we got down to a value of the right type, we win, try inserting into the
1850  // right element.
1851  if (V->getType() == VecEltTy) {
1852  // Inserting null doesn't actually insert any elements.
1853  if (Constant *C = dyn_cast<Constant>(V))
1854  if (C->isNullValue())
1855  return true;
1856 
1857  unsigned ElementIndex = getTypeSizeIndex(Shift, VecEltTy);
1858  if (isBigEndian)
1859  ElementIndex = Elements.size() - ElementIndex - 1;
1860 
1861  // Fail if multiple elements are inserted into this slot.
1862  if (Elements[ElementIndex])
1863  return false;
1864 
1865  Elements[ElementIndex] = V;
1866  return true;
1867  }
1868 
1869  if (Constant *C = dyn_cast<Constant>(V)) {
1870  // Figure out the # elements this provides, and bitcast it or slice it up
1871  // as required.
1872  unsigned NumElts = getTypeSizeIndex(C->getType()->getPrimitiveSizeInBits(),
1873  VecEltTy);
1874  // If the constant is the size of a vector element, we just need to bitcast
1875  // it to the right type so it gets properly inserted.
1876  if (NumElts == 1)
1878  Shift, Elements, VecEltTy, isBigEndian);
1879 
1880  // Okay, this is a constant that covers multiple elements. Slice it up into
1881  // pieces and insert each element-sized piece into the vector.
1882  if (!isa<IntegerType>(C->getType()))
1885  unsigned ElementSize = VecEltTy->getPrimitiveSizeInBits();
1886  Type *ElementIntTy = IntegerType::get(C->getContext(), ElementSize);
1887 
1888  for (unsigned i = 0; i != NumElts; ++i) {
1889  unsigned ShiftI = Shift+i*ElementSize;
1891  ShiftI));
1892  Piece = ConstantExpr::getTrunc(Piece, ElementIntTy);
1893  if (!collectInsertionElements(Piece, ShiftI, Elements, VecEltTy,
1894  isBigEndian))
1895  return false;
1896  }
1897  return true;
1898  }
1899 
1900  if (!V->hasOneUse()) return false;
1901 
1903  if (!I) return false;
1904  switch (I->getOpcode()) {
1905  default: return false; // Unhandled case.
1906  case Instruction::BitCast:
1907  return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
1908  isBigEndian);
1909  case Instruction::ZExt:
1910  if (!isMultipleOfTypeSize(
1912  VecEltTy))
1913  return false;
1914  return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
1915  isBigEndian);
1916  case Instruction::Or:
1917  return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
1918  isBigEndian) &&
1919  collectInsertionElements(I->getOperand(1), Shift, Elements, VecEltTy,
1920  isBigEndian);
1921  case Instruction::Shl: {
1922  // Must be shifting by a constant that is a multiple of the element size.
1924  if (!CI) return false;
1925  Shift += CI->getZExtValue();
1926  if (!isMultipleOfTypeSize(Shift, VecEltTy)) return false;
1927  return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
1928  isBigEndian);
1929  }
1930 
1931  }
1932 }
1933 
1934 
1935 /// If the input is an 'or' instruction, we may be doing shifts and ors to
1936 /// assemble the elements of the vector manually.
1937 /// Try to rip the code out and replace it with insertelements. This is to
1938 /// optimize code like this:
1939 ///
1940 /// %tmp37 = bitcast float %inc to i32
1941 /// %tmp38 = zext i32 %tmp37 to i64
1942 /// %tmp31 = bitcast float %inc5 to i32
1943 /// %tmp32 = zext i32 %tmp31 to i64
1944 /// %tmp33 = shl i64 %tmp32, 32
1945 /// %ins35 = or i64 %tmp33, %tmp38
1946 /// %tmp43 = bitcast i64 %ins35 to <2 x float>
1947 ///
1948 /// Into two insertelements that do "buildvector{%inc, %inc5}".
1950  InstCombiner &IC) {
1951  VectorType *DestVecTy = cast<VectorType>(CI.getType());
1952  Value *IntInput = CI.getOperand(0);
1953 
1954  SmallVector<Value*, 8> Elements(DestVecTy->getNumElements());
1955  if (!collectInsertionElements(IntInput, 0, Elements,
1956  DestVecTy->getElementType(),
1957  IC.getDataLayout().isBigEndian()))
1958  return nullptr;
1959 
1960  // If we succeeded, we know that all of the element are specified by Elements
1961  // or are zero if Elements has a null entry. Recast this as a set of
1962  // insertions.
1963  Value *Result = Constant::getNullValue(CI.getType());
1964  for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
1965  if (!Elements[i]) continue; // Unset element.
1966 
1967  Result = IC.Builder.CreateInsertElement(Result, Elements[i],
1968  IC.Builder.getInt32(i));
1969  }
1970 
1971  return Result;
1972 }
1973 
1974 /// Canonicalize scalar bitcasts of extracted elements into a bitcast of the
1975 /// vector followed by extract element. The backend tends to handle bitcasts of
1976 /// vectors better than bitcasts of scalars because vector registers are
1977 /// usually not type-specific like scalar integer or scalar floating-point.
1979  InstCombiner &IC) {
1980  // TODO: Create and use a pattern matcher for ExtractElementInst.
1981  auto *ExtElt = dyn_cast<ExtractElementInst>(BitCast.getOperand(0));
1982  if (!ExtElt || !ExtElt->hasOneUse())
1983  return nullptr;
1984 
1985  // The bitcast must be to a vectorizable type, otherwise we can't make a new
1986  // type to extract from.
1987  Type *DestType = BitCast.getType();
1988  if (!VectorType::isValidElementType(DestType))
1989  return nullptr;
1990 
1991  unsigned NumElts = ExtElt->getVectorOperandType()->getNumElements();
1992  auto *NewVecType = VectorType::get(DestType, NumElts);
1993  auto *NewBC = IC.Builder.CreateBitCast(ExtElt->getVectorOperand(),
1994  NewVecType, "bc");
1995  return ExtractElementInst::Create(NewBC, ExtElt->getIndexOperand());
1996 }
1997 
1998 /// Change the type of a bitwise logic operation if we can eliminate a bitcast.
2000  InstCombiner::BuilderTy &Builder) {
2001  Type *DestTy = BitCast.getType();
2002  BinaryOperator *BO;
2003  if (!DestTy->isIntOrIntVectorTy() ||
2004  !match(BitCast.getOperand(0), m_OneUse(m_BinOp(BO))) ||
2005  !BO->isBitwiseLogicOp())
2006  return nullptr;
2007 
2008  // FIXME: This transform is restricted to vector types to avoid backend
2009  // problems caused by creating potentially illegal operations. If a fix-up is
2010  // added to handle that situation, we can remove this check.
2011  if (!DestTy->isVectorTy() || !BO->getType()->isVectorTy())
2012  return nullptr;
2013 
2014  Value *X;
2015  if (match(BO->getOperand(0), m_OneUse(m_BitCast(m_Value(X)))) &&
2016  X->getType() == DestTy && !isa<Constant>(X)) {
2017  // bitcast(logic(bitcast(X), Y)) --> logic'(X, bitcast(Y))
2018  Value *CastedOp1 = Builder.CreateBitCast(BO->getOperand(1), DestTy);
2019  return BinaryOperator::Create(BO->getOpcode(), X, CastedOp1);
2020  }
2021 
2022  if (match(BO->getOperand(1), m_OneUse(m_BitCast(m_Value(X)))) &&
2023  X->getType() == DestTy && !isa<Constant>(X)) {
2024  // bitcast(logic(Y, bitcast(X))) --> logic'(bitcast(Y), X)
2025  Value *CastedOp0 = Builder.CreateBitCast(BO->getOperand(0), DestTy);
2026  return BinaryOperator::Create(BO->getOpcode(), CastedOp0, X);
2027  }
2028 
2029  // Canonicalize vector bitcasts to come before vector bitwise logic with a
2030  // constant. This eases recognition of special constants for later ops.
2031  // Example:
2032  // icmp u/s (a ^ signmask), (b ^ signmask) --> icmp s/u a, b
2033  Constant *C;
2034  if (match(BO->getOperand(1), m_Constant(C))) {
2035  // bitcast (logic X, C) --> logic (bitcast X, C')
2036  Value *CastedOp0 = Builder.CreateBitCast(BO->getOperand(0), DestTy);
2037  Value *CastedC = ConstantExpr::getBitCast(C, DestTy);
2038  return BinaryOperator::Create(BO->getOpcode(), CastedOp0, CastedC);
2039  }
2040 
2041  return nullptr;
2042 }
2043 
2044 /// Change the type of a select if we can eliminate a bitcast.
2046  InstCombiner::BuilderTy &Builder) {
2047  Value *Cond, *TVal, *FVal;
2048  if (!match(BitCast.getOperand(0),
2049  m_OneUse(m_Select(m_Value(Cond), m_Value(TVal), m_Value(FVal)))))
2050  return nullptr;
2051 
2052  // A vector select must maintain the same number of elements in its operands.
2053  Type *CondTy = Cond->getType();
2054  Type *DestTy = BitCast.getType();
2055  if (CondTy->isVectorTy()) {
2056  if (!DestTy->isVectorTy())
2057  return nullptr;
2058  if (DestTy->getVectorNumElements() != CondTy->getVectorNumElements())
2059  return nullptr;
2060  }
2061 
2062  // FIXME: This transform is restricted from changing the select between
2063  // scalars and vectors to avoid backend problems caused by creating
2064  // potentially illegal operations. If a fix-up is added to handle that
2065  // situation, we can remove this check.
2066  if (DestTy->isVectorTy() != TVal->getType()->isVectorTy())
2067  return nullptr;
2068 
2069  auto *Sel = cast<Instruction>(BitCast.getOperand(0));
2070  Value *X;
2071  if (match(TVal, m_OneUse(m_BitCast(m_Value(X)))) && X->getType() == DestTy &&
2072  !isa<Constant>(X)) {
2073  // bitcast(select(Cond, bitcast(X), Y)) --> select'(Cond, X, bitcast(Y))
2074  Value *CastedVal = Builder.CreateBitCast(FVal, DestTy);
2075  return SelectInst::Create(Cond, X, CastedVal, "", nullptr, Sel);
2076  }
2077 
2078  if (match(FVal, m_OneUse(m_BitCast(m_Value(X)))) && X->getType() == DestTy &&
2079  !isa<Constant>(X)) {
2080  // bitcast(select(Cond, Y, bitcast(X))) --> select'(Cond, bitcast(Y), X)
2081  Value *CastedVal = Builder.CreateBitCast(TVal, DestTy);
2082  return SelectInst::Create(Cond, CastedVal, X, "", nullptr, Sel);
2083  }
2084 
2085  return nullptr;
2086 }
2087 
2088 /// Check if all users of CI are StoreInsts.
2089 static bool hasStoreUsersOnly(CastInst &CI) {
2090  for (User *U : CI.users()) {
2091  if (!isa<StoreInst>(U))
2092  return false;
2093  }
2094  return true;
2095 }
2096 
2097 /// This function handles following case
2098 ///
2099 /// A -> B cast
2100 /// PHI
2101 /// B -> A cast
2102 ///
2103 /// All the related PHI nodes can be replaced by new PHI nodes with type A.
2104 /// The uses of \p CI can be changed to the new PHI node corresponding to \p PN.
2105 Instruction *InstCombiner::optimizeBitCastFromPhi(CastInst &CI, PHINode *PN) {
2106  // BitCast used by Store can be handled in InstCombineLoadStoreAlloca.cpp.
2107  if (hasStoreUsersOnly(CI))
2108  return nullptr;
2109 
2110  Value *Src = CI.getOperand(0);
2111  Type *SrcTy = Src->getType(); // Type B
2112  Type *DestTy = CI.getType(); // Type A
2113 
2114  SmallVector<PHINode *, 4> PhiWorklist;
2115  SmallSetVector<PHINode *, 4> OldPhiNodes;
2116 
2117  // Find all of the A->B casts and PHI nodes.
2118  // We need to inpect all related PHI nodes, but PHIs can be cyclic, so
2119  // OldPhiNodes is used to track all known PHI nodes, before adding a new
2120  // PHI to PhiWorklist, it is checked against and added to OldPhiNodes first.
2121  PhiWorklist.push_back(PN);
2122  OldPhiNodes.insert(PN);
2123  while (!PhiWorklist.empty()) {
2124  auto *OldPN = PhiWorklist.pop_back_val();
2125  for (Value *IncValue : OldPN->incoming_values()) {
2126  if (isa<Constant>(IncValue))
2127  continue;
2128 
2129  if (auto *LI = dyn_cast<LoadInst>(IncValue)) {
2130  // If there is a sequence of one or more load instructions, each loaded
2131  // value is used as address of later load instruction, bitcast is
2132  // necessary to change the value type, don't optimize it. For
2133  // simplicity we give up if the load address comes from another load.
2134  Value *Addr = LI->getOperand(0);
2135  if (Addr == &CI || isa<LoadInst>(Addr))
2136  return nullptr;
2137  if (LI->hasOneUse() && LI->isSimple())
2138  continue;
2139  // If a LoadInst has more than one use, changing the type of loaded
2140  // value may create another bitcast.
2141  return nullptr;
2142  }
2143 
2144  if (auto *PNode = dyn_cast<PHINode>(IncValue)) {
2145  if (OldPhiNodes.insert(PNode))
2146  PhiWorklist.push_back(PNode);
2147  continue;
2148  }
2149 
2150  auto *BCI = dyn_cast<BitCastInst>(IncValue);
2151  // We can't handle other instructions.
2152  if (!BCI)
2153  return nullptr;
2154 
2155  // Verify it's a A->B cast.
2156  Type *TyA = BCI->getOperand(0)->getType();
2157  Type *TyB = BCI->getType();
2158  if (TyA != DestTy || TyB != SrcTy)
2159  return nullptr;
2160  }
2161  }
2162 
2163  // For each old PHI node, create a corresponding new PHI node with a type A.
2165  for (auto *OldPN : OldPhiNodes) {
2166  Builder.SetInsertPoint(OldPN);
2167  PHINode *NewPN = Builder.CreatePHI(DestTy, OldPN->getNumOperands());
2168  NewPNodes[OldPN] = NewPN;
2169  }
2170 
2171  // Fill in the operands of new PHI nodes.
2172  for (auto *OldPN : OldPhiNodes) {
2173  PHINode *NewPN = NewPNodes[OldPN];
2174  for (unsigned j = 0, e = OldPN->getNumOperands(); j != e; ++j) {
2175  Value *V = OldPN->getOperand(j);
2176  Value *NewV = nullptr;
2177  if (auto *C = dyn_cast<Constant>(V)) {
2178  NewV = ConstantExpr::getBitCast(C, DestTy);
2179  } else if (auto *LI = dyn_cast<LoadInst>(V)) {
2180  Builder.SetInsertPoint(LI->getNextNode());
2181  NewV = Builder.CreateBitCast(LI, DestTy);
2182  Worklist.Add(LI);
2183  } else if (auto *BCI = dyn_cast<BitCastInst>(V)) {
2184  NewV = BCI->getOperand(0);
2185  } else if (auto *PrevPN = dyn_cast<PHINode>(V)) {
2186  NewV = NewPNodes[PrevPN];
2187  }
2188  assert(NewV);
2189  NewPN->addIncoming(NewV, OldPN->getIncomingBlock(j));
2190  }
2191  }
2192 
2193  // If there is a store with type B, change it to type A.
2194  for (User *U : PN->users()) {
2195  auto *SI = dyn_cast<StoreInst>(U);
2196  if (SI && SI->isSimple() && SI->getOperand(0) == PN) {
2197  Builder.SetInsertPoint(SI);
2198  auto *NewBC =
2199  cast<BitCastInst>(Builder.CreateBitCast(NewPNodes[PN], SrcTy));
2200  SI->setOperand(0, NewBC);
2201  Worklist.Add(SI);
2202  assert(hasStoreUsersOnly(*NewBC));
2203  }
2204  }
2205 
2206  return replaceInstUsesWith(CI, NewPNodes[PN]);
2207 }
2208 
2210  // If the operands are integer typed then apply the integer transforms,
2211  // otherwise just apply the common ones.
2212  Value *Src = CI.getOperand(0);
2213  Type *SrcTy = Src->getType();
2214  Type *DestTy = CI.getType();
2215 
2216  // Get rid of casts from one type to the same type. These are useless and can
2217  // be replaced by the operand.
2218  if (DestTy == Src->getType())
2219  return replaceInstUsesWith(CI, Src);
2220 
2221  if (PointerType *DstPTy = dyn_cast<PointerType>(DestTy)) {
2222  PointerType *SrcPTy = cast<PointerType>(SrcTy);
2223  Type *DstElTy = DstPTy->getElementType();
2224  Type *SrcElTy = SrcPTy->getElementType();
2225 
2226  // If we are casting a alloca to a pointer to a type of the same
2227  // size, rewrite the allocation instruction to allocate the "right" type.
2228  // There is no need to modify malloc calls because it is their bitcast that
2229  // needs to be cleaned up.
2230  if (AllocaInst *AI = dyn_cast<AllocaInst>(Src))
2231  if (Instruction *V = PromoteCastOfAllocation(CI, *AI))
2232  return V;
2233 
2234  // When the type pointed to is not sized the cast cannot be
2235  // turned into a gep.
2236  Type *PointeeType =
2237  cast<PointerType>(Src->getType()->getScalarType())->getElementType();
2238  if (!PointeeType->isSized())
2239  return nullptr;
2240 
2241  // If the source and destination are pointers, and this cast is equivalent
2242  // to a getelementptr X, 0, 0, 0... turn it into the appropriate gep.
2243  // This can enhance SROA and other transforms that want type-safe pointers.
2244  unsigned NumZeros = 0;
2245  while (SrcElTy != DstElTy &&
2246  isa<CompositeType>(SrcElTy) && !SrcElTy->isPointerTy() &&
2247  SrcElTy->getNumContainedTypes() /* not "{}" */) {
2248  SrcElTy = cast<CompositeType>(SrcElTy)->getTypeAtIndex(0U);
2249  ++NumZeros;
2250  }
2251 
2252  // If we found a path from the src to dest, create the getelementptr now.
2253  if (SrcElTy == DstElTy) {
2254  SmallVector<Value *, 8> Idxs(NumZeros + 1, Builder.getInt32(0));
2255  return GetElementPtrInst::CreateInBounds(Src, Idxs);
2256  }
2257  }
2258 
2259  if (VectorType *DestVTy = dyn_cast<VectorType>(DestTy)) {
2260  if (DestVTy->getNumElements() == 1 && !SrcTy->isVectorTy()) {
2261  Value *Elem = Builder.CreateBitCast(Src, DestVTy->getElementType());
2262  return InsertElementInst::Create(UndefValue::get(DestTy), Elem,
2264  // FIXME: Canonicalize bitcast(insertelement) -> insertelement(bitcast)
2265  }
2266 
2267  if (isa<IntegerType>(SrcTy)) {
2268  // If this is a cast from an integer to vector, check to see if the input
2269  // is a trunc or zext of a bitcast from vector. If so, we can replace all
2270  // the casts with a shuffle and (potentially) a bitcast.
2271  if (isa<TruncInst>(Src) || isa<ZExtInst>(Src)) {
2272  CastInst *SrcCast = cast<CastInst>(Src);
2273  if (BitCastInst *BCIn = dyn_cast<BitCastInst>(SrcCast->getOperand(0)))
2274  if (isa<VectorType>(BCIn->getOperand(0)->getType()))
2275  if (Instruction *I = optimizeVectorResize(BCIn->getOperand(0),
2276  cast<VectorType>(DestTy), *this))
2277  return I;
2278  }
2279 
2280  // If the input is an 'or' instruction, we may be doing shifts and ors to
2281  // assemble the elements of the vector manually. Try to rip the code out
2282  // and replace it with insertelements.
2283  if (Value *V = optimizeIntegerToVectorInsertions(CI, *this))
2284  return replaceInstUsesWith(CI, V);
2285  }
2286  }
2287 
2288  if (VectorType *SrcVTy = dyn_cast<VectorType>(SrcTy)) {
2289  if (SrcVTy->getNumElements() == 1) {
2290  // If our destination is not a vector, then make this a straight
2291  // scalar-scalar cast.
2292  if (!DestTy->isVectorTy()) {
2293  Value *Elem =
2294  Builder.CreateExtractElement(Src,
2296  return CastInst::Create(Instruction::BitCast, Elem, DestTy);
2297  }
2298 
2299  // Otherwise, see if our source is an insert. If so, then use the scalar
2300  // component directly.
2301  if (InsertElementInst *IEI =
2302  dyn_cast<InsertElementInst>(CI.getOperand(0)))
2303  return CastInst::Create(Instruction::BitCast, IEI->getOperand(1),
2304  DestTy);
2305  }
2306  }
2307 
2308  if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(Src)) {
2309  // Okay, we have (bitcast (shuffle ..)). Check to see if this is
2310  // a bitcast to a vector with the same # elts.
2311  if (SVI->hasOneUse() && DestTy->isVectorTy() &&
2312  DestTy->getVectorNumElements() == SVI->getType()->getNumElements() &&
2313  SVI->getType()->getNumElements() ==
2314  SVI->getOperand(0)->getType()->getVectorNumElements()) {
2315  BitCastInst *Tmp;
2316  // If either of the operands is a cast from CI.getType(), then
2317  // evaluating the shuffle in the casted destination's type will allow
2318  // us to eliminate at least one cast.
2319  if (((Tmp = dyn_cast<BitCastInst>(SVI->getOperand(0))) &&
2320  Tmp->getOperand(0)->getType() == DestTy) ||
2321  ((Tmp = dyn_cast<BitCastInst>(SVI->getOperand(1))) &&
2322  Tmp->getOperand(0)->getType() == DestTy)) {
2323  Value *LHS = Builder.CreateBitCast(SVI->getOperand(0), DestTy);
2324  Value *RHS = Builder.CreateBitCast(SVI->getOperand(1), DestTy);
2325  // Return a new shuffle vector. Use the same element ID's, as we
2326  // know the vector types match #elts.
2327  return new ShuffleVectorInst(LHS, RHS, SVI->getOperand(2));
2328  }
2329  }
2330  }
2331 
2332  // Handle the A->B->A cast, and there is an intervening PHI node.
2333  if (PHINode *PN = dyn_cast<PHINode>(Src))
2334  if (Instruction *I = optimizeBitCastFromPhi(CI, PN))
2335  return I;
2336 
2337  if (Instruction *I = canonicalizeBitCastExtElt(CI, *this))
2338  return I;
2339 
2340  if (Instruction *I = foldBitCastBitwiseLogic(CI, Builder))
2341  return I;
2342 
2343  if (Instruction *I = foldBitCastSelect(CI, Builder))
2344  return I;
2345 
2346  if (SrcTy->isPointerTy())
2347  return commonPointerCastTransforms(CI);
2348  return commonCastTransforms(CI);
2349 }
2350 
2352  // If the destination pointer element type is not the same as the source's
2353  // first do a bitcast to the destination type, and then the addrspacecast.
2354  // This allows the cast to be exposed to other transforms.
2355  Value *Src = CI.getOperand(0);
2356  PointerType *SrcTy = cast<PointerType>(Src->getType()->getScalarType());
2357  PointerType *DestTy = cast<PointerType>(CI.getType()->getScalarType());
2358 
2359  Type *DestElemTy = DestTy->getElementType();
2360  if (SrcTy->getElementType() != DestElemTy) {
2361  Type *MidTy = PointerType::get(DestElemTy, SrcTy->getAddressSpace());
2362  if (VectorType *VT = dyn_cast<VectorType>(CI.getType())) {
2363  // Handle vectors of pointers.
2364  MidTy = VectorType::get(MidTy, VT->getNumElements());
2365  }
2366 
2367  Value *NewBitCast = Builder.CreateBitCast(Src, MidTy);
2368  return new AddrSpaceCastInst(NewBitCast, CI.getType());
2369  }
2370 
2371  return commonPointerCastTransforms(CI);
2372 }
BinaryOp_match< LHS, RHS, Instruction::And > m_And(const LHS &L, const RHS &R)
Definition: PatternMatch.h:574
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:758
void push_back(const T &Elt)
Definition: SmallVector.h:212
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
static GCMetadataPrinterRegistry::Add< ErlangGCPrinter > X("erlang", "erlang-compatible garbage collector")
Type * getSrcTy() const
Return the source type, as a convenience.
Definition: InstrTypes.h:818
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:1542
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:514
DiagnosticInfoOptimizationBase::Argument NV
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
BinaryOps getOpcode() const
Definition: InstrTypes.h:523
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:136
void setAlignment(unsigned Align)
This class represents zero extension of integer types.
Instruction * commonCastTransforms(CastInst &CI)
Implement the transforms common to all CastInst visitors.
This class represents a function call, abstracting a target machine&#39;s calling convention.
static 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:604
This instruction constructs a fixed permutation of two input vectors.
static SelectInst * Create(Value *C, Value *S1, Value *S2, const Twine &NameStr="", Instruction *InsertBefore=nullptr, Instruction *MDFrom=nullptr)
LLVMContext & getContext() const
All values hold a context through their type.
Definition: Value.cpp:728
static 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:818
static Value * lookThroughFPExtensions(Value *V)
Look through floating-point extensions until we get the source value.
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:160
Instruction * visitUIToFP(CastInst &CI)
unsigned getBitWidth() const
Return the number of bits in the APInt.
Definition: APInt.h:1488
BinOpPred_match< LHS, RHS, is_logical_shift_op > m_LogicalShift(const LHS &L, const RHS &R)
Matches logical shift operations.
Definition: PatternMatch.h:766
static Constant * getNullValue(Type *Ty)
Constructor to create a &#39;0&#39; constant of arbitrary type.
Definition: Constants.cpp:207
Instruction * visitFPExt(CastInst &CI)
Instruction * FoldItoFPtoI(Instruction &FI)
unsigned countTrailingZeros() const
Count the number of trailing zero bits.
Definition: APInt.h:1611
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:1518
BinaryOp_match< LHS, RHS, Instruction::Xor > m_Xor(const LHS &L, const RHS &R)
Definition: PatternMatch.h:586
This class represents the LLVM &#39;select&#39; instruction.
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.
This is the base class for all instructions that perform data casts.
Definition: InstrTypes.h:560
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:1247
static Constant * getLShr(Constant *C1, Constant *C2, bool isExact=false)
Definition: Constants.cpp:2193
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.
Definition: PatternMatch.h:912
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:1570
Value * CreateBitCast(Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1448
static bool isMultipleOfTypeSize(unsigned Value, Type *Ty)
Instruction::CastOps getOpcode() const
Return the opcode of this CastInst.
Definition: InstrTypes.h:813
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:4441
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.
Definition: PatternMatch.h:924
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
unsigned getOpcode() const
Returns a member of one of the enums like Instruction::Add.
Definition: Instruction.h:125
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)
Definition: PatternMatch.h:869
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:122
void takeName(Value *V)
Transfer the name from V to this value.
Definition: Value.cpp:292
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:980
This class represents a truncation of integer types.
Value * getOperand(unsigned i) const
Definition: User.h:154
Class to represent pointers.
Definition: DerivedTypes.h:467
SelectPatternResult matchSelectPattern(Value *V, Value *&LHS, Value *&RHS, Instruction::CastOps *CastOp=nullptr)
Pattern match integer [SU]MIN, [SU]MAX and ABS idioms, returning the kind and providing the out param...
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:1678
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:598
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
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:260
unsigned countPopulation() const
Count the number of bits set.
Definition: APInt.h:1637
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:46
BinaryOp_match< LHS, RHS, Instruction::Or > m_Or(const LHS &L, const RHS &R)
Definition: PatternMatch.h:580
bool ult(const APInt &RHS) const
Unsigned less than comparison.
Definition: APInt.h:1164
CastClass_match< OpTy, Instruction::BitCast > m_BitCast(const OpTy &Op)
Matches BitCast.
Definition: PatternMatch.h:900
This is an important base class in LLVM.
Definition: Constant.h:42
unsigned getNumContainedTypes() const
Return the number of types in the derived type.
Definition: Type.h:336
void setUsedWithInAlloca(bool V)
Specify whether this alloca is used to represent the arguments to a call.
Definition: Instructions.h:126
bool isPointerTy() const
True if this is an instance of PointerType.
Definition: Type.h:221
bool MaskedValueIsZero(const Value *V, const APInt &Mask, const DataLayout &DL, unsigned Depth=0, AssumptionCache *AC=nullptr, const Instruction *CxtI=nullptr, const DominatorTree *DT=nullptr)
Return true if &#39;V & Mask&#39; is known to be zero.
ConstantFP - Floating Point Values [float, double].
Definition: Constants.h:264
specificval_ty m_Specific(const Value *V)
Match if we have a specific specified value.
Definition: PatternMatch.h:382
BinaryOp_match< LHS, RHS, Instruction::Shl > m_Shl(const LHS &L, const RHS &R)
Definition: PatternMatch.h:592
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:853
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)
Definition: PatternMatch.h:931
unsigned getAddressSpace() const
Return the address space of the Pointer type.
Definition: DerivedTypes.h:495
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
This class represents a cast from an integer to a pointer.
static Constant * getAllOnesValue(Type *Ty)
Get the all ones value.
Definition: Constants.cpp:261
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:1320
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:1384
Type * getAllocatedType() const
Return the type that is being allocated by the instruction.
Definition: Instructions.h:102
signed greater than
Definition: InstrTypes.h:880
const APFloat & getValueAPF() const
Definition: Constants.h:294
CastClass_match< OpTy, Instruction::SExt > m_SExt(const OpTy &Op)
Matches SExt.
Definition: PatternMatch.h:918
static BinaryOperator * CreateFNeg(Value *Op, const Twine &Name="", Instruction *InsertBefore=nullptr)
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:119
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:116
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:864
Instruction * user_back()
Specialize the methods defined in Value, as we know that an instruction can only be used by other ins...
Definition: Instruction.h:63
Value * CreateInsertElement(Value *Vec, Value *NewElt, Value *Idx, const Twine &Name="")
Definition: IRBuilder.h:1726
static Instruction * shrinkSplatShuffle(TruncInst &Trunc, InstCombiner::BuilderTy &Builder)
Try to narrow the width of a splat shuffle.
Instruction * visitSExt(SExtInst &CI)
signed less than
Definition: InstrTypes.h:882
This class represents a cast from floating point to unsigned integer.
LLVM_NODISCARD T pop_back_val()
Definition: SmallVector.h:385
Instruction * visitZExt(ZExtInst &CI)
ConstantInt * getInt32(uint32_t C)
Get a constant 32-bit value.
Definition: IRBuilder.h:308
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:1542
static Constant * get(Type *Ty, uint64_t V, bool isSigned=false)
If Ty is a vector type, return a Constant with a splat of the given value.
Definition: Constants.cpp:560
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...
static Constant * get(Type *Ty, double V)
This returns a ConstantFP, or a vector containing a splat of a ConstantFP, for the specified value in...
Definition: Constants.cpp:623
Type * getDestTy() const
Return the destination type, as a convenience.
Definition: InstrTypes.h:820
unsigned getNumIncomingValues() const
Return the number of incoming edges.
bool uge(const APInt &RHS) const
Unsigned greater or equal comparison.
Definition: APInt.h:1272
void setOperand(unsigned i, Value *Val)
Definition: User.h:159
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
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:57
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:401
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:927
Instruction * visitTrunc(TruncInst &CI)
static IntegerType * getInt32Ty(LLVMContext &C)
Definition: Type.cpp:176
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:61
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:220
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 Constant * fitsInFPType(ConstantFP *CFP, const fltSemantics &Sem)
Return a Constant* for the specified floating-point constant if it fits in the specified FP type with...
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:1480
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.
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)
#define DEBUG(X)
Definition: Debug.h:118
Type * getElementType() const
Definition: DerivedTypes.h:360
bool hasOneUse() const
Return true if there is exactly one user of this value.
Definition: Value.h:414
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:1575
specific_intval m_SpecificInt(uint64_t V)
Match a specific integer value or vector with all elements equal to the value.
Definition: PatternMatch.h:443
bool isBigEndian() const
Definition: DataLayout.h:217
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:2467
Instruction * visitPtrToInt(PtrToIntInst &CI)
static ExtractElementInst * Create(Value *Vec, Value *Idx, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
op_range incoming_values()
This class represents an extension of floating point types.
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...
constexpr char Args[]
Key for Kernel::Metadata::mArgs.
Type * getElementType() const
Definition: DerivedTypes.h:486
bool isNullValue() const
Determine if all bits are clear.
Definition: APInt.h:399
A wrapper class for inspecting calls to intrinsic functions.
Definition: IntrinsicInst.h:44
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