LLVM  9.0.0svn
VNCoercion.cpp
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6 #include "llvm/IR/IRBuilder.h"
8 #include "llvm/Support/Debug.h"
9 
10 #define DEBUG_TYPE "vncoerce"
11 namespace llvm {
12 namespace VNCoercion {
13 
14 /// Return true if coerceAvailableValueToLoadType will succeed.
15 bool canCoerceMustAliasedValueToLoad(Value *StoredVal, Type *LoadTy,
16  const DataLayout &DL) {
17  // If the loaded or stored value is an first class array or struct, don't try
18  // to transform them. We need to be able to bitcast to integer.
19  if (LoadTy->isStructTy() || LoadTy->isArrayTy() ||
20  StoredVal->getType()->isStructTy() || StoredVal->getType()->isArrayTy())
21  return false;
22 
23  uint64_t StoreSize = DL.getTypeSizeInBits(StoredVal->getType());
24 
25  // The store size must be byte-aligned to support future type casts.
26  if (llvm::alignTo(StoreSize, 8) != StoreSize)
27  return false;
28 
29  // The store has to be at least as big as the load.
30  if (StoreSize < DL.getTypeSizeInBits(LoadTy))
31  return false;
32 
33  // Don't coerce non-integral pointers to integers or vice versa.
34  if (DL.isNonIntegralPointerType(StoredVal->getType()->getScalarType()) !=
36  // As a special case, allow coercion of memset used to initialize
37  // an array w/null. Despite non-integral pointers not generally having a
38  // specific bit pattern, we do assume null is zero.
39  if (auto *CI = dyn_cast<Constant>(StoredVal))
40  return CI->isNullValue();
41  return false;
42  }
43 
44  return true;
45 }
46 
47 template <class T, class HelperClass>
48 static T *coerceAvailableValueToLoadTypeHelper(T *StoredVal, Type *LoadedTy,
49  HelperClass &Helper,
50  const DataLayout &DL) {
51  assert(canCoerceMustAliasedValueToLoad(StoredVal, LoadedTy, DL) &&
52  "precondition violation - materialization can't fail");
53  if (auto *C = dyn_cast<Constant>(StoredVal))
54  if (auto *FoldedStoredVal = ConstantFoldConstant(C, DL))
55  StoredVal = FoldedStoredVal;
56 
57  // If this is already the right type, just return it.
58  Type *StoredValTy = StoredVal->getType();
59 
60  uint64_t StoredValSize = DL.getTypeSizeInBits(StoredValTy);
61  uint64_t LoadedValSize = DL.getTypeSizeInBits(LoadedTy);
62 
63  // If the store and reload are the same size, we can always reuse it.
64  if (StoredValSize == LoadedValSize) {
65  // Pointer to Pointer -> use bitcast.
66  if (StoredValTy->isPtrOrPtrVectorTy() && LoadedTy->isPtrOrPtrVectorTy()) {
67  StoredVal = Helper.CreateBitCast(StoredVal, LoadedTy);
68  } else {
69  // Convert source pointers to integers, which can be bitcast.
70  if (StoredValTy->isPtrOrPtrVectorTy()) {
71  StoredValTy = DL.getIntPtrType(StoredValTy);
72  StoredVal = Helper.CreatePtrToInt(StoredVal, StoredValTy);
73  }
74 
75  Type *TypeToCastTo = LoadedTy;
76  if (TypeToCastTo->isPtrOrPtrVectorTy())
77  TypeToCastTo = DL.getIntPtrType(TypeToCastTo);
78 
79  if (StoredValTy != TypeToCastTo)
80  StoredVal = Helper.CreateBitCast(StoredVal, TypeToCastTo);
81 
82  // Cast to pointer if the load needs a pointer type.
83  if (LoadedTy->isPtrOrPtrVectorTy())
84  StoredVal = Helper.CreateIntToPtr(StoredVal, LoadedTy);
85  }
86 
87  if (auto *C = dyn_cast<ConstantExpr>(StoredVal))
88  if (auto *FoldedStoredVal = ConstantFoldConstant(C, DL))
89  StoredVal = FoldedStoredVal;
90 
91  return StoredVal;
92  }
93  // If the loaded value is smaller than the available value, then we can
94  // extract out a piece from it. If the available value is too small, then we
95  // can't do anything.
96  assert(StoredValSize >= LoadedValSize &&
97  "canCoerceMustAliasedValueToLoad fail");
98 
99  // Convert source pointers to integers, which can be manipulated.
100  if (StoredValTy->isPtrOrPtrVectorTy()) {
101  StoredValTy = DL.getIntPtrType(StoredValTy);
102  StoredVal = Helper.CreatePtrToInt(StoredVal, StoredValTy);
103  }
104 
105  // Convert vectors and fp to integer, which can be manipulated.
106  if (!StoredValTy->isIntegerTy()) {
107  StoredValTy = IntegerType::get(StoredValTy->getContext(), StoredValSize);
108  StoredVal = Helper.CreateBitCast(StoredVal, StoredValTy);
109  }
110 
111  // If this is a big-endian system, we need to shift the value down to the low
112  // bits so that a truncate will work.
113  if (DL.isBigEndian()) {
114  uint64_t ShiftAmt = DL.getTypeStoreSizeInBits(StoredValTy) -
115  DL.getTypeStoreSizeInBits(LoadedTy);
116  StoredVal = Helper.CreateLShr(
117  StoredVal, ConstantInt::get(StoredVal->getType(), ShiftAmt));
118  }
119 
120  // Truncate the integer to the right size now.
121  Type *NewIntTy = IntegerType::get(StoredValTy->getContext(), LoadedValSize);
122  StoredVal = Helper.CreateTruncOrBitCast(StoredVal, NewIntTy);
123 
124  if (LoadedTy != NewIntTy) {
125  // If the result is a pointer, inttoptr.
126  if (LoadedTy->isPtrOrPtrVectorTy())
127  StoredVal = Helper.CreateIntToPtr(StoredVal, LoadedTy);
128  else
129  // Otherwise, bitcast.
130  StoredVal = Helper.CreateBitCast(StoredVal, LoadedTy);
131  }
132 
133  if (auto *C = dyn_cast<Constant>(StoredVal))
134  if (auto *FoldedStoredVal = ConstantFoldConstant(C, DL))
135  StoredVal = FoldedStoredVal;
136 
137  return StoredVal;
138 }
139 
140 /// If we saw a store of a value to memory, and
141 /// then a load from a must-aliased pointer of a different type, try to coerce
142 /// the stored value. LoadedTy is the type of the load we want to replace.
143 /// IRB is IRBuilder used to insert new instructions.
144 ///
145 /// If we can't do it, return null.
147  IRBuilder<> &IRB, const DataLayout &DL) {
148  return coerceAvailableValueToLoadTypeHelper(StoredVal, LoadedTy, IRB, DL);
149 }
150 
151 /// This function is called when we have a memdep query of a load that ends up
152 /// being a clobbering memory write (store, memset, memcpy, memmove). This
153 /// means that the write *may* provide bits used by the load but we can't be
154 /// sure because the pointers don't must-alias.
155 ///
156 /// Check this case to see if there is anything more we can do before we give
157 /// up. This returns -1 if we have to give up, or a byte number in the stored
158 /// value of the piece that feeds the load.
159 static int analyzeLoadFromClobberingWrite(Type *LoadTy, Value *LoadPtr,
160  Value *WritePtr,
161  uint64_t WriteSizeInBits,
162  const DataLayout &DL) {
163  // If the loaded or stored value is a first class array or struct, don't try
164  // to transform them. We need to be able to bitcast to integer.
165  if (LoadTy->isStructTy() || LoadTy->isArrayTy())
166  return -1;
167 
168  int64_t StoreOffset = 0, LoadOffset = 0;
169  Value *StoreBase =
170  GetPointerBaseWithConstantOffset(WritePtr, StoreOffset, DL);
171  Value *LoadBase = GetPointerBaseWithConstantOffset(LoadPtr, LoadOffset, DL);
172  if (StoreBase != LoadBase)
173  return -1;
174 
175  // If the load and store are to the exact same address, they should have been
176  // a must alias. AA must have gotten confused.
177  // FIXME: Study to see if/when this happens. One case is forwarding a memset
178  // to a load from the base of the memset.
179 
180  // If the load and store don't overlap at all, the store doesn't provide
181  // anything to the load. In this case, they really don't alias at all, AA
182  // must have gotten confused.
183  uint64_t LoadSize = DL.getTypeSizeInBits(LoadTy);
184 
185  if ((WriteSizeInBits & 7) | (LoadSize & 7))
186  return -1;
187  uint64_t StoreSize = WriteSizeInBits / 8; // Convert to bytes.
188  LoadSize /= 8;
189 
190  bool isAAFailure = false;
191  if (StoreOffset < LoadOffset)
192  isAAFailure = StoreOffset + int64_t(StoreSize) <= LoadOffset;
193  else
194  isAAFailure = LoadOffset + int64_t(LoadSize) <= StoreOffset;
195 
196  if (isAAFailure)
197  return -1;
198 
199  // If the Load isn't completely contained within the stored bits, we don't
200  // have all the bits to feed it. We could do something crazy in the future
201  // (issue a smaller load then merge the bits in) but this seems unlikely to be
202  // valuable.
203  if (StoreOffset > LoadOffset ||
204  StoreOffset + StoreSize < LoadOffset + LoadSize)
205  return -1;
206 
207  // Okay, we can do this transformation. Return the number of bytes into the
208  // store that the load is.
209  return LoadOffset - StoreOffset;
210 }
211 
212 /// This function is called when we have a
213 /// memdep query of a load that ends up being a clobbering store.
215  StoreInst *DepSI, const DataLayout &DL) {
216  auto *StoredVal = DepSI->getValueOperand();
217 
218  // Cannot handle reading from store of first-class aggregate yet.
219  if (StoredVal->getType()->isStructTy() ||
220  StoredVal->getType()->isArrayTy())
221  return -1;
222 
223  // Don't coerce non-integral pointers to integers or vice versa.
224  if (DL.isNonIntegralPointerType(StoredVal->getType()->getScalarType()) !=
225  DL.isNonIntegralPointerType(LoadTy->getScalarType())) {
226  // Allow casts of zero values to null as a special case
227  auto *CI = dyn_cast<Constant>(StoredVal);
228  if (!CI || !CI->isNullValue())
229  return -1;
230  }
231 
232  Value *StorePtr = DepSI->getPointerOperand();
233  uint64_t StoreSize =
234  DL.getTypeSizeInBits(DepSI->getValueOperand()->getType());
235  return analyzeLoadFromClobberingWrite(LoadTy, LoadPtr, StorePtr, StoreSize,
236  DL);
237 }
238 
239 /// This function is called when we have a
240 /// memdep query of a load that ends up being clobbered by another load. See if
241 /// the other load can feed into the second load.
242 int analyzeLoadFromClobberingLoad(Type *LoadTy, Value *LoadPtr, LoadInst *DepLI,
243  const DataLayout &DL) {
244  // Cannot handle reading from store of first-class aggregate yet.
245  if (DepLI->getType()->isStructTy() || DepLI->getType()->isArrayTy())
246  return -1;
247 
248  // Don't coerce non-integral pointers to integers or vice versa.
249  if (DL.isNonIntegralPointerType(DepLI->getType()->getScalarType()) !=
251  return -1;
252 
253  Value *DepPtr = DepLI->getPointerOperand();
254  uint64_t DepSize = DL.getTypeSizeInBits(DepLI->getType());
255  int R = analyzeLoadFromClobberingWrite(LoadTy, LoadPtr, DepPtr, DepSize, DL);
256  if (R != -1)
257  return R;
258 
259  // If we have a load/load clobber an DepLI can be widened to cover this load,
260  // then we should widen it!
261  int64_t LoadOffs = 0;
262  const Value *LoadBase =
263  GetPointerBaseWithConstantOffset(LoadPtr, LoadOffs, DL);
264  unsigned LoadSize = DL.getTypeStoreSize(LoadTy);
265 
267  LoadBase, LoadOffs, LoadSize, DepLI);
268  if (Size == 0)
269  return -1;
270 
271  // Check non-obvious conditions enforced by MDA which we rely on for being
272  // able to materialize this potentially available value
273  assert(DepLI->isSimple() && "Cannot widen volatile/atomic load!");
274  assert(DepLI->getType()->isIntegerTy() && "Can't widen non-integer load");
275 
276  return analyzeLoadFromClobberingWrite(LoadTy, LoadPtr, DepPtr, Size * 8, DL);
277 }
278 
280  MemIntrinsic *MI, const DataLayout &DL) {
281  // If the mem operation is a non-constant size, we can't handle it.
282  ConstantInt *SizeCst = dyn_cast<ConstantInt>(MI->getLength());
283  if (!SizeCst)
284  return -1;
285  uint64_t MemSizeInBits = SizeCst->getZExtValue() * 8;
286 
287  // If this is memset, we just need to see if the offset is valid in the size
288  // of the memset..
289  if (MI->getIntrinsicID() == Intrinsic::memset) {
290  if (DL.isNonIntegralPointerType(LoadTy->getScalarType())) {
291  auto *CI = dyn_cast<ConstantInt>(cast<MemSetInst>(MI)->getValue());
292  if (!CI || !CI->isZero())
293  return -1;
294  }
295  return analyzeLoadFromClobberingWrite(LoadTy, LoadPtr, MI->getDest(),
296  MemSizeInBits, DL);
297  }
298 
299  // If we have a memcpy/memmove, the only case we can handle is if this is a
300  // copy from constant memory. In that case, we can read directly from the
301  // constant memory.
302  MemTransferInst *MTI = cast<MemTransferInst>(MI);
303 
304  Constant *Src = dyn_cast<Constant>(MTI->getSource());
305  if (!Src)
306  return -1;
307 
309  if (!GV || !GV->isConstant())
310  return -1;
311 
312  // See if the access is within the bounds of the transfer.
313  int Offset = analyzeLoadFromClobberingWrite(LoadTy, LoadPtr, MI->getDest(),
314  MemSizeInBits, DL);
315  if (Offset == -1)
316  return Offset;
317 
318  // Don't coerce non-integral pointers to integers or vice versa, and the
319  // memtransfer is implicitly a raw byte code
320  if (DL.isNonIntegralPointerType(LoadTy->getScalarType()))
321  // TODO: Can allow nullptrs from constant zeros
322  return -1;
323 
324  unsigned AS = Src->getType()->getPointerAddressSpace();
325  // Otherwise, see if we can constant fold a load from the constant with the
326  // offset applied as appropriate.
327  Src =
328  ConstantExpr::getBitCast(Src, Type::getInt8PtrTy(Src->getContext(), AS));
329  Constant *OffsetCst =
330  ConstantInt::get(Type::getInt64Ty(Src->getContext()), (unsigned)Offset);
331  Src = ConstantExpr::getGetElementPtr(Type::getInt8Ty(Src->getContext()), Src,
332  OffsetCst);
333  Src = ConstantExpr::getBitCast(Src, PointerType::get(LoadTy, AS));
334  if (ConstantFoldLoadFromConstPtr(Src, LoadTy, DL))
335  return Offset;
336  return -1;
337 }
338 
339 template <class T, class HelperClass>
340 static T *getStoreValueForLoadHelper(T *SrcVal, unsigned Offset, Type *LoadTy,
341  HelperClass &Helper,
342  const DataLayout &DL) {
343  LLVMContext &Ctx = SrcVal->getType()->getContext();
344 
345  // If two pointers are in the same address space, they have the same size,
346  // so we don't need to do any truncation, etc. This avoids introducing
347  // ptrtoint instructions for pointers that may be non-integral.
348  if (SrcVal->getType()->isPointerTy() && LoadTy->isPointerTy() &&
349  cast<PointerType>(SrcVal->getType())->getAddressSpace() ==
350  cast<PointerType>(LoadTy)->getAddressSpace()) {
351  return SrcVal;
352  }
353 
354  uint64_t StoreSize = (DL.getTypeSizeInBits(SrcVal->getType()) + 7) / 8;
355  uint64_t LoadSize = (DL.getTypeSizeInBits(LoadTy) + 7) / 8;
356  // Compute which bits of the stored value are being used by the load. Convert
357  // to an integer type to start with.
358  if (SrcVal->getType()->isPtrOrPtrVectorTy())
359  SrcVal = Helper.CreatePtrToInt(SrcVal, DL.getIntPtrType(SrcVal->getType()));
360  if (!SrcVal->getType()->isIntegerTy())
361  SrcVal = Helper.CreateBitCast(SrcVal, IntegerType::get(Ctx, StoreSize * 8));
362 
363  // Shift the bits to the least significant depending on endianness.
364  unsigned ShiftAmt;
365  if (DL.isLittleEndian())
366  ShiftAmt = Offset * 8;
367  else
368  ShiftAmt = (StoreSize - LoadSize - Offset) * 8;
369  if (ShiftAmt)
370  SrcVal = Helper.CreateLShr(SrcVal,
371  ConstantInt::get(SrcVal->getType(), ShiftAmt));
372 
373  if (LoadSize != StoreSize)
374  SrcVal = Helper.CreateTruncOrBitCast(SrcVal,
375  IntegerType::get(Ctx, LoadSize * 8));
376  return SrcVal;
377 }
378 
379 /// This function is called when we have a memdep query of a load that ends up
380 /// being a clobbering store. This means that the store provides bits used by
381 /// the load but the pointers don't must-alias. Check this case to see if
382 /// there is anything more we can do before we give up.
383 Value *getStoreValueForLoad(Value *SrcVal, unsigned Offset, Type *LoadTy,
384  Instruction *InsertPt, const DataLayout &DL) {
385 
386  IRBuilder<> Builder(InsertPt);
387  SrcVal = getStoreValueForLoadHelper(SrcVal, Offset, LoadTy, Builder, DL);
388  return coerceAvailableValueToLoadTypeHelper(SrcVal, LoadTy, Builder, DL);
389 }
390 
392  Type *LoadTy, const DataLayout &DL) {
394  SrcVal = getStoreValueForLoadHelper(SrcVal, Offset, LoadTy, F, DL);
395  return coerceAvailableValueToLoadTypeHelper(SrcVal, LoadTy, F, DL);
396 }
397 
398 /// This function is called when we have a memdep query of a load that ends up
399 /// being a clobbering load. This means that the load *may* provide bits used
400 /// by the load but we can't be sure because the pointers don't must-alias.
401 /// Check this case to see if there is anything more we can do before we give
402 /// up.
403 Value *getLoadValueForLoad(LoadInst *SrcVal, unsigned Offset, Type *LoadTy,
404  Instruction *InsertPt, const DataLayout &DL) {
405  // If Offset+LoadTy exceeds the size of SrcVal, then we must be wanting to
406  // widen SrcVal out to a larger load.
407  unsigned SrcValStoreSize = DL.getTypeStoreSize(SrcVal->getType());
408  unsigned LoadSize = DL.getTypeStoreSize(LoadTy);
409  if (Offset + LoadSize > SrcValStoreSize) {
410  assert(SrcVal->isSimple() && "Cannot widen volatile/atomic load!");
411  assert(SrcVal->getType()->isIntegerTy() && "Can't widen non-integer load");
412  // If we have a load/load clobber an DepLI can be widened to cover this
413  // load, then we should widen it to the next power of 2 size big enough!
414  unsigned NewLoadSize = Offset + LoadSize;
415  if (!isPowerOf2_32(NewLoadSize))
416  NewLoadSize = NextPowerOf2(NewLoadSize);
417 
418  Value *PtrVal = SrcVal->getPointerOperand();
419  // Insert the new load after the old load. This ensures that subsequent
420  // memdep queries will find the new load. We can't easily remove the old
421  // load completely because it is already in the value numbering table.
422  IRBuilder<> Builder(SrcVal->getParent(), ++BasicBlock::iterator(SrcVal));
423  Type *DestTy = IntegerType::get(LoadTy->getContext(), NewLoadSize * 8);
424  Type *DestPTy =
425  PointerType::get(DestTy, PtrVal->getType()->getPointerAddressSpace());
426  Builder.SetCurrentDebugLocation(SrcVal->getDebugLoc());
427  PtrVal = Builder.CreateBitCast(PtrVal, DestPTy);
428  LoadInst *NewLoad = Builder.CreateLoad(DestTy, PtrVal);
429  NewLoad->takeName(SrcVal);
430  NewLoad->setAlignment(SrcVal->getAlignment());
431 
432  LLVM_DEBUG(dbgs() << "GVN WIDENED LOAD: " << *SrcVal << "\n");
433  LLVM_DEBUG(dbgs() << "TO: " << *NewLoad << "\n");
434 
435  // Replace uses of the original load with the wider load. On a big endian
436  // system, we need to shift down to get the relevant bits.
437  Value *RV = NewLoad;
438  if (DL.isBigEndian())
439  RV = Builder.CreateLShr(RV, (NewLoadSize - SrcValStoreSize) * 8);
440  RV = Builder.CreateTrunc(RV, SrcVal->getType());
441  SrcVal->replaceAllUsesWith(RV);
442 
443  SrcVal = NewLoad;
444  }
445 
446  return getStoreValueForLoad(SrcVal, Offset, LoadTy, InsertPt, DL);
447 }
448 
450  Type *LoadTy, const DataLayout &DL) {
451  unsigned SrcValStoreSize = DL.getTypeStoreSize(SrcVal->getType());
452  unsigned LoadSize = DL.getTypeStoreSize(LoadTy);
453  if (Offset + LoadSize > SrcValStoreSize)
454  return nullptr;
455  return getConstantStoreValueForLoad(SrcVal, Offset, LoadTy, DL);
456 }
457 
458 template <class T, class HelperClass>
460  Type *LoadTy, HelperClass &Helper,
461  const DataLayout &DL) {
462  LLVMContext &Ctx = LoadTy->getContext();
463  uint64_t LoadSize = DL.getTypeSizeInBits(LoadTy) / 8;
464 
465  // We know that this method is only called when the mem transfer fully
466  // provides the bits for the load.
467  if (MemSetInst *MSI = dyn_cast<MemSetInst>(SrcInst)) {
468  // memset(P, 'x', 1234) -> splat('x'), even if x is a variable, and
469  // independently of what the offset is.
470  T *Val = cast<T>(MSI->getValue());
471  if (LoadSize != 1)
472  Val =
473  Helper.CreateZExtOrBitCast(Val, IntegerType::get(Ctx, LoadSize * 8));
474  T *OneElt = Val;
475 
476  // Splat the value out to the right number of bits.
477  for (unsigned NumBytesSet = 1; NumBytesSet != LoadSize;) {
478  // If we can double the number of bytes set, do it.
479  if (NumBytesSet * 2 <= LoadSize) {
480  T *ShVal = Helper.CreateShl(
481  Val, ConstantInt::get(Val->getType(), NumBytesSet * 8));
482  Val = Helper.CreateOr(Val, ShVal);
483  NumBytesSet <<= 1;
484  continue;
485  }
486 
487  // Otherwise insert one byte at a time.
488  T *ShVal = Helper.CreateShl(Val, ConstantInt::get(Val->getType(), 1 * 8));
489  Val = Helper.CreateOr(OneElt, ShVal);
490  ++NumBytesSet;
491  }
492 
493  return coerceAvailableValueToLoadTypeHelper(Val, LoadTy, Helper, DL);
494  }
495 
496  // Otherwise, this is a memcpy/memmove from a constant global.
497  MemTransferInst *MTI = cast<MemTransferInst>(SrcInst);
498  Constant *Src = cast<Constant>(MTI->getSource());
499  unsigned AS = Src->getType()->getPointerAddressSpace();
500 
501  // Otherwise, see if we can constant fold a load from the constant with the
502  // offset applied as appropriate.
503  Src =
504  ConstantExpr::getBitCast(Src, Type::getInt8PtrTy(Src->getContext(), AS));
505  Constant *OffsetCst =
506  ConstantInt::get(Type::getInt64Ty(Src->getContext()), (unsigned)Offset);
507  Src = ConstantExpr::getGetElementPtr(Type::getInt8Ty(Src->getContext()), Src,
508  OffsetCst);
509  Src = ConstantExpr::getBitCast(Src, PointerType::get(LoadTy, AS));
510  return ConstantFoldLoadFromConstPtr(Src, LoadTy, DL);
511 }
512 
513 /// This function is called when we have a
514 /// memdep query of a load that ends up being a clobbering mem intrinsic.
516  Type *LoadTy, Instruction *InsertPt,
517  const DataLayout &DL) {
518  IRBuilder<> Builder(InsertPt);
519  return getMemInstValueForLoadHelper<Value, IRBuilder<>>(SrcInst, Offset,
520  LoadTy, Builder, DL);
521 }
522 
524  Type *LoadTy, const DataLayout &DL) {
525  // The only case analyzeLoadFromClobberingMemInst cannot be converted to a
526  // constant is when it's a memset of a non-constant.
527  if (auto *MSI = dyn_cast<MemSetInst>(SrcInst))
528  if (!isa<Constant>(MSI->getValue()))
529  return nullptr;
531  return getMemInstValueForLoadHelper<Constant, ConstantFolder>(SrcInst, Offset,
532  LoadTy, F, DL);
533 }
534 } // namespace VNCoercion
535 } // namespace llvm
uint64_t CallInst * C
Value * getValueOperand()
Definition: Instructions.h:409
A parsed version of the target data layout string in and methods for querying it. ...
Definition: DataLayout.h:110
uint64_t getTypeStoreSizeInBits(Type *Ty) const
Returns the maximum number of bits that may be overwritten by storing the specified type; always a mu...
Definition: DataLayout.h:452
bool isSimple() const
Definition: Instructions.h:276
int analyzeLoadFromClobberingLoad(Type *LoadTy, Value *LoadPtr, LoadInst *DepLI, const DataLayout &DL)
This function determines whether a value for the pointer LoadPtr can be extracted from the load at De...
Definition: VNCoercion.cpp:242
This class represents lattice values for constants.
Definition: AllocatorList.h:23
static Constant * getGetElementPtr(Type *Ty, Constant *C, ArrayRef< Constant *> IdxList, bool InBounds=false, Optional< unsigned > InRangeIndex=None, Type *OnlyIfReducedTy=nullptr)
Getelementptr form.
Definition: Constants.h:1153
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:629
This class wraps the llvm.memset intrinsic.
F(f)
uint64_t alignTo(uint64_t Value, uint64_t Align, uint64_t Skew=0)
Returns the next integer (mod 2**64) that is greater than or equal to Value and is a multiple of Alig...
Definition: MathExtras.h:684
unsigned getPointerAddressSpace() const
Get the address space of this pointer or pointer vector type.
Definition: DerivedTypes.h:534
An instruction for reading from memory.
Definition: Instructions.h:167
static IntegerType * getInt64Ty(LLVMContext &C)
Definition: Type.cpp:176
Value * getLength() const
Constant * getConstantMemInstValueForLoad(MemIntrinsic *SrcInst, unsigned Offset, Type *LoadTy, const DataLayout &DL)
Definition: VNCoercion.cpp:523
Value * getMemInstValueForLoad(MemIntrinsic *SrcInst, unsigned Offset, Type *LoadTy, Instruction *InsertPt, const DataLayout &DL)
If analyzeLoadFromClobberingMemInst returned an offset, this function can be used to actually perform...
Definition: VNCoercion.cpp:515
LLVMContext & getContext() const
Return the LLVMContext in which this type was uniqued.
Definition: Type.h:129
Value * getDest() const
This is just like getRawDest, but it strips off any cast instructions (including addrspacecast) that ...
Value * coerceAvailableValueToLoadType(Value *StoredVal, Type *LoadedTy, IRBuilder<> &IRB, const DataLayout &DL)
If we saw a store of a value to memory, and then a load from a must-aliased pointer of a different ty...
Definition: VNCoercion.cpp:146
static unsigned getLoadLoadClobberFullWidthSize(const Value *MemLocBase, int64_t MemLocOffs, unsigned MemLocSize, const LoadInst *LI)
Looks at a memory location for a load (specified by MemLocBase, Offs, and Size) and compares it again...
bool isConstant() const
If the value is a global constant, its value is immutable throughout the runtime execution of the pro...
int analyzeLoadFromClobberingMemInst(Type *LoadTy, Value *LoadPtr, MemIntrinsic *DepMI, const DataLayout &DL)
This function determines whether a value for the pointer LoadPtr can be extracted from the memory int...
Definition: VNCoercion.cpp:279
Constant * getConstantStoreValueForLoad(Constant *SrcVal, unsigned Offset, Type *LoadTy, const DataLayout &DL)
Definition: VNCoercion.cpp:391
bool isIntegerTy() const
True if this is an instance of IntegerType.
Definition: Type.h:196
This provides a uniform API for creating instructions and inserting them into a basic block: either a...
Definition: IRBuilder.h:742
Constant * ConstantFoldConstant(const Constant *C, const DataLayout &DL, const TargetLibraryInfo *TLI=nullptr)
ConstantFoldConstant - Attempt to fold the constant using the specified DataLayout.
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:244
Value * GetPointerBaseWithConstantOffset(Value *Ptr, int64_t &Offset, const DataLayout &DL)
Analyze the specified pointer to see if it can be expressed as a base pointer plus a constant offset...
bool canCoerceMustAliasedValueToLoad(Value *StoredVal, Type *LoadTy, const DataLayout &DL)
Return true if CoerceAvailableValueToLoadType would succeed if it was called.
Definition: VNCoercion.cpp:15
static T * getStoreValueForLoadHelper(T *SrcVal, unsigned Offset, Type *LoadTy, HelperClass &Helper, const DataLayout &DL)
Definition: VNCoercion.cpp:340
ConstantFolder - Create constants with minimum, target independent, folding.
bool isLittleEndian() const
Layout endianness...
Definition: DataLayout.h:232
An instruction for storing to memory.
Definition: Instructions.h:320
void replaceAllUsesWith(Value *V)
Change all uses of this to point to a new Value.
Definition: Value.cpp:429
void takeName(Value *V)
Transfer the name from V to this value.
Definition: Value.cpp:291
int analyzeLoadFromClobberingStore(Type *LoadTy, Value *LoadPtr, StoreInst *DepSI, const DataLayout &DL)
This function determines whether a value for the pointer LoadPtr can be extracted from the store at D...
Definition: VNCoercion.cpp:214
Type * getScalarType() const
If this is a vector type, return the element type, otherwise return &#39;this&#39;.
Definition: Type.h:303
static Constant * getBitCast(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1782
IntegerType * getIntPtrType(LLVMContext &C, unsigned AddressSpace=0) const
Returns an integer type with size at least as big as that of a pointer in the given address space...
Definition: DataLayout.cpp:769
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:148
constexpr bool isPowerOf2_32(uint32_t Value)
Return true if the argument is a power of two > 0.
Definition: MathExtras.h:428
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:45
This is an important class for using LLVM in a threaded context.
Definition: LLVMContext.h:64
This is an important base class in LLVM.
Definition: Constant.h:41
Constant * getConstantLoadValueForLoad(Constant *SrcVal, unsigned Offset, Type *LoadTy, const DataLayout &DL)
Definition: VNCoercion.cpp:449
bool isPointerTy() const
True if this is an instance of PointerType.
Definition: Type.h:223
static int analyzeLoadFromClobberingWrite(Type *LoadTy, Value *LoadPtr, Value *WritePtr, uint64_t WriteSizeInBits, const DataLayout &DL)
This function is called when we have a memdep query of a load that ends up being a clobbering memory ...
Definition: VNCoercion.cpp:159
Value * getPointerOperand()
Definition: Instructions.h:284
Value * getLoadValueForLoad(LoadInst *SrcVal, unsigned Offset, Type *LoadTy, Instruction *InsertPt, const DataLayout &DL)
If analyzeLoadFromClobberingLoad returned an offset, this function can be used to actually perform th...
Definition: VNCoercion.cpp:403
void setAlignment(unsigned Align)
Constant * ConstantFoldLoadFromConstPtr(Constant *C, Type *Ty, const DataLayout &DL)
ConstantFoldLoadFromConstPtr - Return the value that a load from C would produce if it is constant an...
uint64_t NextPowerOf2(uint64_t A)
Returns the next power of two (in 64-bits) that is strictly greater than A.
Definition: MathExtras.h:639
static PointerType * getInt8PtrTy(LLVMContext &C, unsigned AS=0)
Definition: Type.cpp:219
Value * GetUnderlyingObject(Value *V, const DataLayout &DL, unsigned MaxLookup=6)
This method strips off any GEP address adjustments and pointer casts from the specified value...
Intrinsic::ID getIntrinsicID() const
Return the intrinsic ID of this intrinsic.
Definition: IntrinsicInst.h:50
bool isPtrOrPtrVectorTy() const
Return true if this is a pointer type or a vector of pointer types.
Definition: Type.h:226
static IntegerType * get(LLVMContext &C, unsigned NumBits)
This static method is the primary way of constructing an IntegerType.
Definition: Type.cpp:239
This is the common base class for memset/memcpy/memmove.
This is the shared class of boolean and integer constants.
Definition: Constants.h:83
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:631
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
static T * coerceAvailableValueToLoadTypeHelper(T *StoredVal, Type *LoadedTy, HelperClass &Helper, const DataLayout &DL)
Definition: VNCoercion.cpp:48
InstListType::iterator iterator
Instruction iterators...
Definition: BasicBlock.h:89
bool isNonIntegralPointerType(PointerType *PT) const
Definition: DataLayout.h:376
uint64_t getTypeSizeInBits(Type *Ty) const
Size examples:
Definition: DataLayout.h:593
This class wraps the llvm.memcpy/memmove intrinsics.
const DebugLoc & getDebugLoc() const
Return the debug location for this node as a DebugLoc.
Definition: Instruction.h:321
unsigned getAlignment() const
Return the alignment of the access that is being performed.
Definition: Instructions.h:240
Value * getStoreValueForLoad(Value *SrcVal, unsigned Offset, Type *LoadTy, Instruction *InsertPt, const DataLayout &DL)
If analyzeLoadFromClobberingStore returned an offset, this function can be used to actually perform t...
Definition: VNCoercion.cpp:383
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:332
uint32_t Size
Definition: Profile.cpp:46
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
LLVM Value Representation.
Definition: Value.h:72
uint64_t getTypeStoreSize(Type *Ty) const
Returns the maximum number of bytes that may be overwritten by storing the specified type...
Definition: DataLayout.h:444
T * getMemInstValueForLoadHelper(MemIntrinsic *SrcInst, unsigned Offset, Type *LoadTy, HelperClass &Helper, const DataLayout &DL)
Definition: VNCoercion.cpp:459
Value * getSource() const
This is just like getRawSource, but it strips off any cast instructions that feed it...
IRTranslator LLVM IR MI
bool isBigEndian() const
Definition: DataLayout.h:233
#define LLVM_DEBUG(X)
Definition: Debug.h:122
Value * getPointerOperand()
Definition: Instructions.h:412
static IntegerType * getInt8Ty(LLVMContext &C)
Definition: Type.cpp:173
bool isStructTy() const
True if this is an instance of StructType.
Definition: Type.h:217
bool isArrayTy() const
True if this is an instance of ArrayType.
Definition: Type.h:220
const BasicBlock * getParent() const
Definition: Instruction.h:66