LLVM  8.0.0svn
ConstantFold.cpp
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1 //===- ConstantFold.cpp - LLVM constant folder ----------------------------===//
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 folding of constants for LLVM. This implements the
11 // (internal) ConstantFold.h interface, which is used by the
12 // ConstantExpr::get* methods to automatically fold constants when possible.
13 //
14 // The current constant folding implementation is implemented in two pieces: the
15 // pieces that don't need DataLayout, and the pieces that do. This is to avoid
16 // a dependence in IR on Target.
17 //
18 //===----------------------------------------------------------------------===//
19 
20 #include "ConstantFold.h"
21 #include "llvm/ADT/APSInt.h"
22 #include "llvm/ADT/SmallVector.h"
23 #include "llvm/IR/Constants.h"
24 #include "llvm/IR/DerivedTypes.h"
25 #include "llvm/IR/Function.h"
27 #include "llvm/IR/GlobalAlias.h"
28 #include "llvm/IR/GlobalVariable.h"
29 #include "llvm/IR/Instructions.h"
30 #include "llvm/IR/Operator.h"
31 #include "llvm/IR/PatternMatch.h"
35 using namespace llvm;
36 using namespace llvm::PatternMatch;
37 
38 //===----------------------------------------------------------------------===//
39 // ConstantFold*Instruction Implementations
40 //===----------------------------------------------------------------------===//
41 
42 /// Convert the specified vector Constant node to the specified vector type.
43 /// At this point, we know that the elements of the input vector constant are
44 /// all simple integer or FP values.
46 
47  if (CV->isAllOnesValue()) return Constant::getAllOnesValue(DstTy);
48  if (CV->isNullValue()) return Constant::getNullValue(DstTy);
49 
50  // If this cast changes element count then we can't handle it here:
51  // doing so requires endianness information. This should be handled by
52  // Analysis/ConstantFolding.cpp
53  unsigned NumElts = DstTy->getNumElements();
54  if (NumElts != CV->getType()->getVectorNumElements())
55  return nullptr;
56 
57  Type *DstEltTy = DstTy->getElementType();
58 
60  Type *Ty = IntegerType::get(CV->getContext(), 32);
61  for (unsigned i = 0; i != NumElts; ++i) {
62  Constant *C =
64  C = ConstantExpr::getBitCast(C, DstEltTy);
65  Result.push_back(C);
66  }
67 
68  return ConstantVector::get(Result);
69 }
70 
71 /// This function determines which opcode to use to fold two constant cast
72 /// expressions together. It uses CastInst::isEliminableCastPair to determine
73 /// the opcode. Consequently its just a wrapper around that function.
74 /// Determine if it is valid to fold a cast of a cast
75 static unsigned
77  unsigned opc, ///< opcode of the second cast constant expression
78  ConstantExpr *Op, ///< the first cast constant expression
79  Type *DstTy ///< destination type of the first cast
80 ) {
81  assert(Op && Op->isCast() && "Can't fold cast of cast without a cast!");
82  assert(DstTy && DstTy->isFirstClassType() && "Invalid cast destination type");
83  assert(CastInst::isCast(opc) && "Invalid cast opcode");
84 
85  // The types and opcodes for the two Cast constant expressions
86  Type *SrcTy = Op->getOperand(0)->getType();
87  Type *MidTy = Op->getType();
90 
91  // Assume that pointers are never more than 64 bits wide, and only use this
92  // for the middle type. Otherwise we could end up folding away illegal
93  // bitcasts between address spaces with different sizes.
94  IntegerType *FakeIntPtrTy = Type::getInt64Ty(DstTy->getContext());
95 
96  // Let CastInst::isEliminableCastPair do the heavy lifting.
97  return CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy, DstTy,
98  nullptr, FakeIntPtrTy, nullptr);
99 }
100 
101 static Constant *FoldBitCast(Constant *V, Type *DestTy) {
102  Type *SrcTy = V->getType();
103  if (SrcTy == DestTy)
104  return V; // no-op cast
105 
106  // Check to see if we are casting a pointer to an aggregate to a pointer to
107  // the first element. If so, return the appropriate GEP instruction.
108  if (PointerType *PTy = dyn_cast<PointerType>(V->getType()))
109  if (PointerType *DPTy = dyn_cast<PointerType>(DestTy))
110  if (PTy->getAddressSpace() == DPTy->getAddressSpace()
111  && PTy->getElementType()->isSized()) {
112  SmallVector<Value*, 8> IdxList;
113  Value *Zero =
114  Constant::getNullValue(Type::getInt32Ty(DPTy->getContext()));
115  IdxList.push_back(Zero);
116  Type *ElTy = PTy->getElementType();
117  while (ElTy != DPTy->getElementType()) {
118  if (StructType *STy = dyn_cast<StructType>(ElTy)) {
119  if (STy->getNumElements() == 0) break;
120  ElTy = STy->getElementType(0);
121  IdxList.push_back(Zero);
122  } else if (SequentialType *STy =
123  dyn_cast<SequentialType>(ElTy)) {
124  ElTy = STy->getElementType();
125  IdxList.push_back(Zero);
126  } else {
127  break;
128  }
129  }
130 
131  if (ElTy == DPTy->getElementType())
132  // This GEP is inbounds because all indices are zero.
133  return ConstantExpr::getInBoundsGetElementPtr(PTy->getElementType(),
134  V, IdxList);
135  }
136 
137  // Handle casts from one vector constant to another. We know that the src
138  // and dest type have the same size (otherwise its an illegal cast).
139  if (VectorType *DestPTy = dyn_cast<VectorType>(DestTy)) {
140  if (VectorType *SrcTy = dyn_cast<VectorType>(V->getType())) {
141  assert(DestPTy->getBitWidth() == SrcTy->getBitWidth() &&
142  "Not cast between same sized vectors!");
143  SrcTy = nullptr;
144  // First, check for null. Undef is already handled.
145  if (isa<ConstantAggregateZero>(V))
146  return Constant::getNullValue(DestTy);
147 
148  // Handle ConstantVector and ConstantAggregateVector.
149  return BitCastConstantVector(V, DestPTy);
150  }
151 
152  // Canonicalize scalar-to-vector bitcasts into vector-to-vector bitcasts
153  // This allows for other simplifications (although some of them
154  // can only be handled by Analysis/ConstantFolding.cpp).
155  if (isa<ConstantInt>(V) || isa<ConstantFP>(V))
156  return ConstantExpr::getBitCast(ConstantVector::get(V), DestPTy);
157  }
158 
159  // Finally, implement bitcast folding now. The code below doesn't handle
160  // bitcast right.
161  if (isa<ConstantPointerNull>(V)) // ptr->ptr cast.
162  return ConstantPointerNull::get(cast<PointerType>(DestTy));
163 
164  // Handle integral constant input.
165  if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
166  if (DestTy->isIntegerTy())
167  // Integral -> Integral. This is a no-op because the bit widths must
168  // be the same. Consequently, we just fold to V.
169  return V;
170 
171  // See note below regarding the PPC_FP128 restriction.
172  if (DestTy->isFloatingPointTy() && !DestTy->isPPC_FP128Ty())
173  return ConstantFP::get(DestTy->getContext(),
174  APFloat(DestTy->getFltSemantics(),
175  CI->getValue()));
176 
177  // Otherwise, can't fold this (vector?)
178  return nullptr;
179  }
180 
181  // Handle ConstantFP input: FP -> Integral.
182  if (ConstantFP *FP = dyn_cast<ConstantFP>(V)) {
183  // PPC_FP128 is really the sum of two consecutive doubles, where the first
184  // double is always stored first in memory, regardless of the target
185  // endianness. The memory layout of i128, however, depends on the target
186  // endianness, and so we can't fold this without target endianness
187  // information. This should instead be handled by
188  // Analysis/ConstantFolding.cpp
189  if (FP->getType()->isPPC_FP128Ty())
190  return nullptr;
191 
192  // Make sure dest type is compatible with the folded integer constant.
193  if (!DestTy->isIntegerTy())
194  return nullptr;
195 
196  return ConstantInt::get(FP->getContext(),
197  FP->getValueAPF().bitcastToAPInt());
198  }
199 
200  return nullptr;
201 }
202 
203 
204 /// V is an integer constant which only has a subset of its bytes used.
205 /// The bytes used are indicated by ByteStart (which is the first byte used,
206 /// counting from the least significant byte) and ByteSize, which is the number
207 /// of bytes used.
208 ///
209 /// This function analyzes the specified constant to see if the specified byte
210 /// range can be returned as a simplified constant. If so, the constant is
211 /// returned, otherwise null is returned.
212 static Constant *ExtractConstantBytes(Constant *C, unsigned ByteStart,
213  unsigned ByteSize) {
214  assert(C->getType()->isIntegerTy() &&
215  (cast<IntegerType>(C->getType())->getBitWidth() & 7) == 0 &&
216  "Non-byte sized integer input");
217  unsigned CSize = cast<IntegerType>(C->getType())->getBitWidth()/8;
218  assert(ByteSize && "Must be accessing some piece");
219  assert(ByteStart+ByteSize <= CSize && "Extracting invalid piece from input");
220  assert(ByteSize != CSize && "Should not extract everything");
221 
222  // Constant Integers are simple.
223  if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
224  APInt V = CI->getValue();
225  if (ByteStart)
226  V.lshrInPlace(ByteStart*8);
227  V = V.trunc(ByteSize*8);
228  return ConstantInt::get(CI->getContext(), V);
229  }
230 
231  // In the input is a constant expr, we might be able to recursively simplify.
232  // If not, we definitely can't do anything.
234  if (!CE) return nullptr;
235 
236  switch (CE->getOpcode()) {
237  default: return nullptr;
238  case Instruction::Or: {
239  Constant *RHS = ExtractConstantBytes(CE->getOperand(1), ByteStart,ByteSize);
240  if (!RHS)
241  return nullptr;
242 
243  // X | -1 -> -1.
244  if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS))
245  if (RHSC->isMinusOne())
246  return RHSC;
247 
248  Constant *LHS = ExtractConstantBytes(CE->getOperand(0), ByteStart,ByteSize);
249  if (!LHS)
250  return nullptr;
251  return ConstantExpr::getOr(LHS, RHS);
252  }
253  case Instruction::And: {
254  Constant *RHS = ExtractConstantBytes(CE->getOperand(1), ByteStart,ByteSize);
255  if (!RHS)
256  return nullptr;
257 
258  // X & 0 -> 0.
259  if (RHS->isNullValue())
260  return RHS;
261 
262  Constant *LHS = ExtractConstantBytes(CE->getOperand(0), ByteStart,ByteSize);
263  if (!LHS)
264  return nullptr;
265  return ConstantExpr::getAnd(LHS, RHS);
266  }
267  case Instruction::LShr: {
268  ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
269  if (!Amt)
270  return nullptr;
271  unsigned ShAmt = Amt->getZExtValue();
272  // Cannot analyze non-byte shifts.
273  if ((ShAmt & 7) != 0)
274  return nullptr;
275  ShAmt >>= 3;
276 
277  // If the extract is known to be all zeros, return zero.
278  if (ByteStart >= CSize-ShAmt)
279  return Constant::getNullValue(IntegerType::get(CE->getContext(),
280  ByteSize*8));
281  // If the extract is known to be fully in the input, extract it.
282  if (ByteStart+ByteSize+ShAmt <= CSize)
283  return ExtractConstantBytes(CE->getOperand(0), ByteStart+ShAmt, ByteSize);
284 
285  // TODO: Handle the 'partially zero' case.
286  return nullptr;
287  }
288 
289  case Instruction::Shl: {
290  ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
291  if (!Amt)
292  return nullptr;
293  unsigned ShAmt = Amt->getZExtValue();
294  // Cannot analyze non-byte shifts.
295  if ((ShAmt & 7) != 0)
296  return nullptr;
297  ShAmt >>= 3;
298 
299  // If the extract is known to be all zeros, return zero.
300  if (ByteStart+ByteSize <= ShAmt)
301  return Constant::getNullValue(IntegerType::get(CE->getContext(),
302  ByteSize*8));
303  // If the extract is known to be fully in the input, extract it.
304  if (ByteStart >= ShAmt)
305  return ExtractConstantBytes(CE->getOperand(0), ByteStart-ShAmt, ByteSize);
306 
307  // TODO: Handle the 'partially zero' case.
308  return nullptr;
309  }
310 
311  case Instruction::ZExt: {
312  unsigned SrcBitSize =
313  cast<IntegerType>(CE->getOperand(0)->getType())->getBitWidth();
314 
315  // If extracting something that is completely zero, return 0.
316  if (ByteStart*8 >= SrcBitSize)
317  return Constant::getNullValue(IntegerType::get(CE->getContext(),
318  ByteSize*8));
319 
320  // If exactly extracting the input, return it.
321  if (ByteStart == 0 && ByteSize*8 == SrcBitSize)
322  return CE->getOperand(0);
323 
324  // If extracting something completely in the input, if the input is a
325  // multiple of 8 bits, recurse.
326  if ((SrcBitSize&7) == 0 && (ByteStart+ByteSize)*8 <= SrcBitSize)
327  return ExtractConstantBytes(CE->getOperand(0), ByteStart, ByteSize);
328 
329  // Otherwise, if extracting a subset of the input, which is not multiple of
330  // 8 bits, do a shift and trunc to get the bits.
331  if ((ByteStart+ByteSize)*8 < SrcBitSize) {
332  assert((SrcBitSize&7) && "Shouldn't get byte sized case here");
333  Constant *Res = CE->getOperand(0);
334  if (ByteStart)
335  Res = ConstantExpr::getLShr(Res,
336  ConstantInt::get(Res->getType(), ByteStart*8));
338  ByteSize*8));
339  }
340 
341  // TODO: Handle the 'partially zero' case.
342  return nullptr;
343  }
344  }
345 }
346 
347 /// Return a ConstantExpr with type DestTy for sizeof on Ty, with any known
348 /// factors factored out. If Folded is false, return null if no factoring was
349 /// possible, to avoid endlessly bouncing an unfoldable expression back into the
350 /// top-level folder.
351 static Constant *getFoldedSizeOf(Type *Ty, Type *DestTy, bool Folded) {
352  if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
353  Constant *N = ConstantInt::get(DestTy, ATy->getNumElements());
354  Constant *E = getFoldedSizeOf(ATy->getElementType(), DestTy, true);
355  return ConstantExpr::getNUWMul(E, N);
356  }
357 
358  if (StructType *STy = dyn_cast<StructType>(Ty))
359  if (!STy->isPacked()) {
360  unsigned NumElems = STy->getNumElements();
361  // An empty struct has size zero.
362  if (NumElems == 0)
363  return ConstantExpr::getNullValue(DestTy);
364  // Check for a struct with all members having the same size.
365  Constant *MemberSize =
366  getFoldedSizeOf(STy->getElementType(0), DestTy, true);
367  bool AllSame = true;
368  for (unsigned i = 1; i != NumElems; ++i)
369  if (MemberSize !=
370  getFoldedSizeOf(STy->getElementType(i), DestTy, true)) {
371  AllSame = false;
372  break;
373  }
374  if (AllSame) {
375  Constant *N = ConstantInt::get(DestTy, NumElems);
376  return ConstantExpr::getNUWMul(MemberSize, N);
377  }
378  }
379 
380  // Pointer size doesn't depend on the pointee type, so canonicalize them
381  // to an arbitrary pointee.
382  if (PointerType *PTy = dyn_cast<PointerType>(Ty))
383  if (!PTy->getElementType()->isIntegerTy(1))
384  return
385  getFoldedSizeOf(PointerType::get(IntegerType::get(PTy->getContext(), 1),
386  PTy->getAddressSpace()),
387  DestTy, true);
388 
389  // If there's no interesting folding happening, bail so that we don't create
390  // a constant that looks like it needs folding but really doesn't.
391  if (!Folded)
392  return nullptr;
393 
394  // Base case: Get a regular sizeof expression.
397  DestTy, false),
398  C, DestTy);
399  return C;
400 }
401 
402 /// Return a ConstantExpr with type DestTy for alignof on Ty, with any known
403 /// factors factored out. If Folded is false, return null if no factoring was
404 /// possible, to avoid endlessly bouncing an unfoldable expression back into the
405 /// top-level folder.
406 static Constant *getFoldedAlignOf(Type *Ty, Type *DestTy, bool Folded) {
407  // The alignment of an array is equal to the alignment of the
408  // array element. Note that this is not always true for vectors.
409  if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
410  Constant *C = ConstantExpr::getAlignOf(ATy->getElementType());
412  DestTy,
413  false),
414  C, DestTy);
415  return C;
416  }
417 
418  if (StructType *STy = dyn_cast<StructType>(Ty)) {
419  // Packed structs always have an alignment of 1.
420  if (STy->isPacked())
421  return ConstantInt::get(DestTy, 1);
422 
423  // Otherwise, struct alignment is the maximum alignment of any member.
424  // Without target data, we can't compare much, but we can check to see
425  // if all the members have the same alignment.
426  unsigned NumElems = STy->getNumElements();
427  // An empty struct has minimal alignment.
428  if (NumElems == 0)
429  return ConstantInt::get(DestTy, 1);
430  // Check for a struct with all members having the same alignment.
431  Constant *MemberAlign =
432  getFoldedAlignOf(STy->getElementType(0), DestTy, true);
433  bool AllSame = true;
434  for (unsigned i = 1; i != NumElems; ++i)
435  if (MemberAlign != getFoldedAlignOf(STy->getElementType(i), DestTy, true)) {
436  AllSame = false;
437  break;
438  }
439  if (AllSame)
440  return MemberAlign;
441  }
442 
443  // Pointer alignment doesn't depend on the pointee type, so canonicalize them
444  // to an arbitrary pointee.
445  if (PointerType *PTy = dyn_cast<PointerType>(Ty))
446  if (!PTy->getElementType()->isIntegerTy(1))
447  return
449  1),
450  PTy->getAddressSpace()),
451  DestTy, true);
452 
453  // If there's no interesting folding happening, bail so that we don't create
454  // a constant that looks like it needs folding but really doesn't.
455  if (!Folded)
456  return nullptr;
457 
458  // Base case: Get a regular alignof expression.
461  DestTy, false),
462  C, DestTy);
463  return C;
464 }
465 
466 /// Return a ConstantExpr with type DestTy for offsetof on Ty and FieldNo, with
467 /// any known factors factored out. If Folded is false, return null if no
468 /// factoring was possible, to avoid endlessly bouncing an unfoldable expression
469 /// back into the top-level folder.
470 static Constant *getFoldedOffsetOf(Type *Ty, Constant *FieldNo, Type *DestTy,
471  bool Folded) {
472  if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
474  DestTy, false),
475  FieldNo, DestTy);
476  Constant *E = getFoldedSizeOf(ATy->getElementType(), DestTy, true);
477  return ConstantExpr::getNUWMul(E, N);
478  }
479 
480  if (StructType *STy = dyn_cast<StructType>(Ty))
481  if (!STy->isPacked()) {
482  unsigned NumElems = STy->getNumElements();
483  // An empty struct has no members.
484  if (NumElems == 0)
485  return nullptr;
486  // Check for a struct with all members having the same size.
487  Constant *MemberSize =
488  getFoldedSizeOf(STy->getElementType(0), DestTy, true);
489  bool AllSame = true;
490  for (unsigned i = 1; i != NumElems; ++i)
491  if (MemberSize !=
492  getFoldedSizeOf(STy->getElementType(i), DestTy, true)) {
493  AllSame = false;
494  break;
495  }
496  if (AllSame) {
498  false,
499  DestTy,
500  false),
501  FieldNo, DestTy);
502  return ConstantExpr::getNUWMul(MemberSize, N);
503  }
504  }
505 
506  // If there's no interesting folding happening, bail so that we don't create
507  // a constant that looks like it needs folding but really doesn't.
508  if (!Folded)
509  return nullptr;
510 
511  // Base case: Get a regular offsetof expression.
512  Constant *C = ConstantExpr::getOffsetOf(Ty, FieldNo);
514  DestTy, false),
515  C, DestTy);
516  return C;
517 }
518 
520  Type *DestTy) {
521  if (isa<UndefValue>(V)) {
522  // zext(undef) = 0, because the top bits will be zero.
523  // sext(undef) = 0, because the top bits will all be the same.
524  // [us]itofp(undef) = 0, because the result value is bounded.
525  if (opc == Instruction::ZExt || opc == Instruction::SExt ||
526  opc == Instruction::UIToFP || opc == Instruction::SIToFP)
527  return Constant::getNullValue(DestTy);
528  return UndefValue::get(DestTy);
529  }
530 
531  if (V->isNullValue() && !DestTy->isX86_MMXTy() &&
532  opc != Instruction::AddrSpaceCast)
533  return Constant::getNullValue(DestTy);
534 
535  // If the cast operand is a constant expression, there's a few things we can
536  // do to try to simplify it.
537  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
538  if (CE->isCast()) {
539  // Try hard to fold cast of cast because they are often eliminable.
540  if (unsigned newOpc = foldConstantCastPair(opc, CE, DestTy))
541  return ConstantExpr::getCast(newOpc, CE->getOperand(0), DestTy);
542  } else if (CE->getOpcode() == Instruction::GetElementPtr &&
543  // Do not fold addrspacecast (gep 0, .., 0). It might make the
544  // addrspacecast uncanonicalized.
545  opc != Instruction::AddrSpaceCast &&
546  // Do not fold bitcast (gep) with inrange index, as this loses
547  // information.
548  !cast<GEPOperator>(CE)->getInRangeIndex().hasValue() &&
549  // Do not fold if the gep type is a vector, as bitcasting
550  // operand 0 of a vector gep will result in a bitcast between
551  // different sizes.
552  !CE->getType()->isVectorTy()) {
553  // If all of the indexes in the GEP are null values, there is no pointer
554  // adjustment going on. We might as well cast the source pointer.
555  bool isAllNull = true;
556  for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
557  if (!CE->getOperand(i)->isNullValue()) {
558  isAllNull = false;
559  break;
560  }
561  if (isAllNull)
562  // This is casting one pointer type to another, always BitCast
563  return ConstantExpr::getPointerCast(CE->getOperand(0), DestTy);
564  }
565  }
566 
567  // If the cast operand is a constant vector, perform the cast by
568  // operating on each element. In the cast of bitcasts, the element
569  // count may be mismatched; don't attempt to handle that here.
570  if ((isa<ConstantVector>(V) || isa<ConstantDataVector>(V)) &&
571  DestTy->isVectorTy() &&
572  DestTy->getVectorNumElements() == V->getType()->getVectorNumElements()) {
574  VectorType *DestVecTy = cast<VectorType>(DestTy);
575  Type *DstEltTy = DestVecTy->getElementType();
576  Type *Ty = IntegerType::get(V->getContext(), 32);
577  for (unsigned i = 0, e = V->getType()->getVectorNumElements(); i != e; ++i) {
578  Constant *C =
580  res.push_back(ConstantExpr::getCast(opc, C, DstEltTy));
581  }
582  return ConstantVector::get(res);
583  }
584 
585  // We actually have to do a cast now. Perform the cast according to the
586  // opcode specified.
587  switch (opc) {
588  default:
589  llvm_unreachable("Failed to cast constant expression");
590  case Instruction::FPTrunc:
591  case Instruction::FPExt:
592  if (ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
593  bool ignored;
594  APFloat Val = FPC->getValueAPF();
595  Val.convert(DestTy->isHalfTy() ? APFloat::IEEEhalf() :
596  DestTy->isFloatTy() ? APFloat::IEEEsingle() :
597  DestTy->isDoubleTy() ? APFloat::IEEEdouble() :
599  DestTy->isFP128Ty() ? APFloat::IEEEquad() :
601  APFloat::Bogus(),
602  APFloat::rmNearestTiesToEven, &ignored);
603  return ConstantFP::get(V->getContext(), Val);
604  }
605  return nullptr; // Can't fold.
606  case Instruction::FPToUI:
607  case Instruction::FPToSI:
608  if (ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
609  const APFloat &V = FPC->getValueAPF();
610  bool ignored;
611  uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
612  APSInt IntVal(DestBitWidth, opc == Instruction::FPToUI);
613  if (APFloat::opInvalidOp ==
614  V.convertToInteger(IntVal, APFloat::rmTowardZero, &ignored)) {
615  // Undefined behavior invoked - the destination type can't represent
616  // the input constant.
617  return UndefValue::get(DestTy);
618  }
619  return ConstantInt::get(FPC->getContext(), IntVal);
620  }
621  return nullptr; // Can't fold.
622  case Instruction::IntToPtr: //always treated as unsigned
623  if (V->isNullValue()) // Is it an integral null value?
624  return ConstantPointerNull::get(cast<PointerType>(DestTy));
625  return nullptr; // Other pointer types cannot be casted
626  case Instruction::PtrToInt: // always treated as unsigned
627  // Is it a null pointer value?
628  if (V->isNullValue())
629  return ConstantInt::get(DestTy, 0);
630  // If this is a sizeof-like expression, pull out multiplications by
631  // known factors to expose them to subsequent folding. If it's an
632  // alignof-like expression, factor out known factors.
633  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
634  if (CE->getOpcode() == Instruction::GetElementPtr &&
635  CE->getOperand(0)->isNullValue()) {
636  // FIXME: Looks like getFoldedSizeOf(), getFoldedOffsetOf() and
637  // getFoldedAlignOf() don't handle the case when DestTy is a vector of
638  // pointers yet. We end up in asserts in CastInst::getCastOpcode (see
639  // test/Analysis/ConstantFolding/cast-vector.ll). I've only seen this
640  // happen in one "real" C-code test case, so it does not seem to be an
641  // important optimization to handle vectors here. For now, simply bail
642  // out.
643  if (DestTy->isVectorTy())
644  return nullptr;
645  GEPOperator *GEPO = cast<GEPOperator>(CE);
646  Type *Ty = GEPO->getSourceElementType();
647  if (CE->getNumOperands() == 2) {
648  // Handle a sizeof-like expression.
649  Constant *Idx = CE->getOperand(1);
650  bool isOne = isa<ConstantInt>(Idx) && cast<ConstantInt>(Idx)->isOne();
651  if (Constant *C = getFoldedSizeOf(Ty, DestTy, !isOne)) {
653  DestTy, false),
654  Idx, DestTy);
655  return ConstantExpr::getMul(C, Idx);
656  }
657  } else if (CE->getNumOperands() == 3 &&
658  CE->getOperand(1)->isNullValue()) {
659  // Handle an alignof-like expression.
660  if (StructType *STy = dyn_cast<StructType>(Ty))
661  if (!STy->isPacked()) {
662  ConstantInt *CI = cast<ConstantInt>(CE->getOperand(2));
663  if (CI->isOne() &&
664  STy->getNumElements() == 2 &&
665  STy->getElementType(0)->isIntegerTy(1)) {
666  return getFoldedAlignOf(STy->getElementType(1), DestTy, false);
667  }
668  }
669  // Handle an offsetof-like expression.
670  if (Ty->isStructTy() || Ty->isArrayTy()) {
671  if (Constant *C = getFoldedOffsetOf(Ty, CE->getOperand(2),
672  DestTy, false))
673  return C;
674  }
675  }
676  }
677  // Other pointer types cannot be casted
678  return nullptr;
679  case Instruction::UIToFP:
680  case Instruction::SIToFP:
681  if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
682  const APInt &api = CI->getValue();
683  APFloat apf(DestTy->getFltSemantics(),
685  apf.convertFromAPInt(api, opc==Instruction::SIToFP,
687  return ConstantFP::get(V->getContext(), apf);
688  }
689  return nullptr;
690  case Instruction::ZExt:
691  if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
692  uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
693  return ConstantInt::get(V->getContext(),
694  CI->getValue().zext(BitWidth));
695  }
696  return nullptr;
697  case Instruction::SExt:
698  if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
699  uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
700  return ConstantInt::get(V->getContext(),
701  CI->getValue().sext(BitWidth));
702  }
703  return nullptr;
704  case Instruction::Trunc: {
705  if (V->getType()->isVectorTy())
706  return nullptr;
707 
708  uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
709  if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
710  return ConstantInt::get(V->getContext(),
711  CI->getValue().trunc(DestBitWidth));
712  }
713 
714  // The input must be a constantexpr. See if we can simplify this based on
715  // the bytes we are demanding. Only do this if the source and dest are an
716  // even multiple of a byte.
717  if ((DestBitWidth & 7) == 0 &&
718  (cast<IntegerType>(V->getType())->getBitWidth() & 7) == 0)
719  if (Constant *Res = ExtractConstantBytes(V, 0, DestBitWidth / 8))
720  return Res;
721 
722  return nullptr;
723  }
724  case Instruction::BitCast:
725  return FoldBitCast(V, DestTy);
726  case Instruction::AddrSpaceCast:
727  return nullptr;
728  }
729 }
730 
732  Constant *V1, Constant *V2) {
733  // Check for i1 and vector true/false conditions.
734  if (Cond->isNullValue()) return V2;
735  if (Cond->isAllOnesValue()) return V1;
736 
737  // If the condition is a vector constant, fold the result elementwise.
738  if (ConstantVector *CondV = dyn_cast<ConstantVector>(Cond)) {
740  Type *Ty = IntegerType::get(CondV->getContext(), 32);
741  for (unsigned i = 0, e = V1->getType()->getVectorNumElements(); i != e;++i){
742  Constant *V;
744  ConstantInt::get(Ty, i));
746  ConstantInt::get(Ty, i));
747  Constant *Cond = dyn_cast<Constant>(CondV->getOperand(i));
748  if (V1Element == V2Element) {
749  V = V1Element;
750  } else if (isa<UndefValue>(Cond)) {
751  V = isa<UndefValue>(V1Element) ? V1Element : V2Element;
752  } else {
753  if (!isa<ConstantInt>(Cond)) break;
754  V = Cond->isNullValue() ? V2Element : V1Element;
755  }
756  Result.push_back(V);
757  }
758 
759  // If we were able to build the vector, return it.
760  if (Result.size() == V1->getType()->getVectorNumElements())
761  return ConstantVector::get(Result);
762  }
763 
764  if (isa<UndefValue>(Cond)) {
765  if (isa<UndefValue>(V1)) return V1;
766  return V2;
767  }
768  if (isa<UndefValue>(V1)) return V2;
769  if (isa<UndefValue>(V2)) return V1;
770  if (V1 == V2) return V1;
771 
772  if (ConstantExpr *TrueVal = dyn_cast<ConstantExpr>(V1)) {
773  if (TrueVal->getOpcode() == Instruction::Select)
774  if (TrueVal->getOperand(0) == Cond)
775  return ConstantExpr::getSelect(Cond, TrueVal->getOperand(1), V2);
776  }
777  if (ConstantExpr *FalseVal = dyn_cast<ConstantExpr>(V2)) {
778  if (FalseVal->getOpcode() == Instruction::Select)
779  if (FalseVal->getOperand(0) == Cond)
780  return ConstantExpr::getSelect(Cond, V1, FalseVal->getOperand(2));
781  }
782 
783  return nullptr;
784 }
785 
787  Constant *Idx) {
788  if (isa<UndefValue>(Val)) // ee(undef, x) -> undef
789  return UndefValue::get(Val->getType()->getVectorElementType());
790  if (Val->isNullValue()) // ee(zero, x) -> zero
792  // ee({w,x,y,z}, undef) -> undef
793  if (isa<UndefValue>(Idx))
794  return UndefValue::get(Val->getType()->getVectorElementType());
795 
796  if (ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx)) {
797  // ee({w,x,y,z}, wrong_value) -> undef
798  if (CIdx->uge(Val->getType()->getVectorNumElements()))
799  return UndefValue::get(Val->getType()->getVectorElementType());
800  return Val->getAggregateElement(CIdx->getZExtValue());
801  }
802  return nullptr;
803 }
804 
806  Constant *Elt,
807  Constant *Idx) {
808  if (isa<UndefValue>(Idx))
809  return UndefValue::get(Val->getType());
810 
811  ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx);
812  if (!CIdx) return nullptr;
813 
814  unsigned NumElts = Val->getType()->getVectorNumElements();
815  if (CIdx->uge(NumElts))
816  return UndefValue::get(Val->getType());
817 
819  Result.reserve(NumElts);
820  auto *Ty = Type::getInt32Ty(Val->getContext());
821  uint64_t IdxVal = CIdx->getZExtValue();
822  for (unsigned i = 0; i != NumElts; ++i) {
823  if (i == IdxVal) {
824  Result.push_back(Elt);
825  continue;
826  }
827 
829  Result.push_back(C);
830  }
831 
832  return ConstantVector::get(Result);
833 }
834 
836  Constant *V2,
837  Constant *Mask) {
838  unsigned MaskNumElts = Mask->getType()->getVectorNumElements();
839  Type *EltTy = V1->getType()->getVectorElementType();
840 
841  // Undefined shuffle mask -> undefined value.
842  if (isa<UndefValue>(Mask))
843  return UndefValue::get(VectorType::get(EltTy, MaskNumElts));
844 
845  // Don't break the bitcode reader hack.
846  if (isa<ConstantExpr>(Mask)) return nullptr;
847 
848  unsigned SrcNumElts = V1->getType()->getVectorNumElements();
849 
850  // Loop over the shuffle mask, evaluating each element.
852  for (unsigned i = 0; i != MaskNumElts; ++i) {
853  int Elt = ShuffleVectorInst::getMaskValue(Mask, i);
854  if (Elt == -1) {
855  Result.push_back(UndefValue::get(EltTy));
856  continue;
857  }
858  Constant *InElt;
859  if (unsigned(Elt) >= SrcNumElts*2)
860  InElt = UndefValue::get(EltTy);
861  else if (unsigned(Elt) >= SrcNumElts) {
862  Type *Ty = IntegerType::get(V2->getContext(), 32);
863  InElt =
865  ConstantInt::get(Ty, Elt - SrcNumElts));
866  } else {
867  Type *Ty = IntegerType::get(V1->getContext(), 32);
869  }
870  Result.push_back(InElt);
871  }
872 
873  return ConstantVector::get(Result);
874 }
875 
877  ArrayRef<unsigned> Idxs) {
878  // Base case: no indices, so return the entire value.
879  if (Idxs.empty())
880  return Agg;
881 
882  if (Constant *C = Agg->getAggregateElement(Idxs[0]))
884 
885  return nullptr;
886 }
887 
889  Constant *Val,
890  ArrayRef<unsigned> Idxs) {
891  // Base case: no indices, so replace the entire value.
892  if (Idxs.empty())
893  return Val;
894 
895  unsigned NumElts;
896  if (StructType *ST = dyn_cast<StructType>(Agg->getType()))
897  NumElts = ST->getNumElements();
898  else
899  NumElts = cast<SequentialType>(Agg->getType())->getNumElements();
900 
902  for (unsigned i = 0; i != NumElts; ++i) {
903  Constant *C = Agg->getAggregateElement(i);
904  if (!C) return nullptr;
905 
906  if (Idxs[0] == i)
907  C = ConstantFoldInsertValueInstruction(C, Val, Idxs.slice(1));
908 
909  Result.push_back(C);
910  }
911 
912  if (StructType *ST = dyn_cast<StructType>(Agg->getType()))
913  return ConstantStruct::get(ST, Result);
914  if (ArrayType *AT = dyn_cast<ArrayType>(Agg->getType()))
915  return ConstantArray::get(AT, Result);
916  return ConstantVector::get(Result);
917 }
918 
920  Constant *C2) {
921  assert(Instruction::isBinaryOp(Opcode) && "Non-binary instruction detected");
922 
923  // Handle scalar UndefValue. Vectors are always evaluated per element.
924  bool HasScalarUndef = !C1->getType()->isVectorTy() &&
925  (isa<UndefValue>(C1) || isa<UndefValue>(C2));
926  if (HasScalarUndef) {
927  switch (static_cast<Instruction::BinaryOps>(Opcode)) {
928  case Instruction::Xor:
929  if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
930  // Handle undef ^ undef -> 0 special case. This is a common
931  // idiom (misuse).
932  return Constant::getNullValue(C1->getType());
934  case Instruction::Add:
935  case Instruction::Sub:
936  return UndefValue::get(C1->getType());
937  case Instruction::And:
938  if (isa<UndefValue>(C1) && isa<UndefValue>(C2)) // undef & undef -> undef
939  return C1;
940  return Constant::getNullValue(C1->getType()); // undef & X -> 0
941  case Instruction::Mul: {
942  // undef * undef -> undef
943  if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
944  return C1;
945  const APInt *CV;
946  // X * undef -> undef if X is odd
947  if (match(C1, m_APInt(CV)) || match(C2, m_APInt(CV)))
948  if ((*CV)[0])
949  return UndefValue::get(C1->getType());
950 
951  // X * undef -> 0 otherwise
952  return Constant::getNullValue(C1->getType());
953  }
954  case Instruction::SDiv:
955  case Instruction::UDiv:
956  // X / undef -> undef
957  if (isa<UndefValue>(C2))
958  return C2;
959  // undef / 0 -> undef
960  // undef / 1 -> undef
961  if (match(C2, m_Zero()) || match(C2, m_One()))
962  return C1;
963  // undef / X -> 0 otherwise
964  return Constant::getNullValue(C1->getType());
965  case Instruction::URem:
966  case Instruction::SRem:
967  // X % undef -> undef
968  if (match(C2, m_Undef()))
969  return C2;
970  // undef % 0 -> undef
971  if (match(C2, m_Zero()))
972  return C1;
973  // undef % X -> 0 otherwise
974  return Constant::getNullValue(C1->getType());
975  case Instruction::Or: // X | undef -> -1
976  if (isa<UndefValue>(C1) && isa<UndefValue>(C2)) // undef | undef -> undef
977  return C1;
978  return Constant::getAllOnesValue(C1->getType()); // undef | X -> ~0
979  case Instruction::LShr:
980  // X >>l undef -> undef
981  if (isa<UndefValue>(C2))
982  return C2;
983  // undef >>l 0 -> undef
984  if (match(C2, m_Zero()))
985  return C1;
986  // undef >>l X -> 0
987  return Constant::getNullValue(C1->getType());
988  case Instruction::AShr:
989  // X >>a undef -> undef
990  if (isa<UndefValue>(C2))
991  return C2;
992  // undef >>a 0 -> undef
993  if (match(C2, m_Zero()))
994  return C1;
995  // TODO: undef >>a X -> undef if the shift is exact
996  // undef >>a X -> 0
997  return Constant::getNullValue(C1->getType());
998  case Instruction::Shl:
999  // X << undef -> undef
1000  if (isa<UndefValue>(C2))
1001  return C2;
1002  // undef << 0 -> undef
1003  if (match(C2, m_Zero()))
1004  return C1;
1005  // undef << X -> 0
1006  return Constant::getNullValue(C1->getType());
1007  case Instruction::FAdd:
1008  case Instruction::FSub:
1009  case Instruction::FMul:
1010  case Instruction::FDiv:
1011  case Instruction::FRem:
1012  // [any flop] undef, undef -> undef
1013  if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
1014  return C1;
1015  // [any flop] C, undef -> NaN
1016  // [any flop] undef, C -> NaN
1017  // We could potentially specialize NaN/Inf constants vs. 'normal'
1018  // constants (possibly differently depending on opcode and operand). This
1019  // would allow returning undef sometimes. But it is always safe to fold to
1020  // NaN because we can choose the undef operand as NaN, and any FP opcode
1021  // with a NaN operand will propagate NaN.
1022  return ConstantFP::getNaN(C1->getType());
1023  case Instruction::BinaryOpsEnd:
1024  llvm_unreachable("Invalid BinaryOp");
1025  }
1026  }
1027 
1028  // Neither constant should be UndefValue, unless these are vector constants.
1029  assert(!HasScalarUndef && "Unexpected UndefValue");
1030 
1031  // Handle simplifications when the RHS is a constant int.
1032  if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
1033  switch (Opcode) {
1034  case Instruction::Add:
1035  if (CI2->isZero()) return C1; // X + 0 == X
1036  break;
1037  case Instruction::Sub:
1038  if (CI2->isZero()) return C1; // X - 0 == X
1039  break;
1040  case Instruction::Mul:
1041  if (CI2->isZero()) return C2; // X * 0 == 0
1042  if (CI2->isOne())
1043  return C1; // X * 1 == X
1044  break;
1045  case Instruction::UDiv:
1046  case Instruction::SDiv:
1047  if (CI2->isOne())
1048  return C1; // X / 1 == X
1049  if (CI2->isZero())
1050  return UndefValue::get(CI2->getType()); // X / 0 == undef
1051  break;
1052  case Instruction::URem:
1053  case Instruction::SRem:
1054  if (CI2->isOne())
1055  return Constant::getNullValue(CI2->getType()); // X % 1 == 0
1056  if (CI2->isZero())
1057  return UndefValue::get(CI2->getType()); // X % 0 == undef
1058  break;
1059  case Instruction::And:
1060  if (CI2->isZero()) return C2; // X & 0 == 0
1061  if (CI2->isMinusOne())
1062  return C1; // X & -1 == X
1063 
1064  if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1065  // (zext i32 to i64) & 4294967295 -> (zext i32 to i64)
1066  if (CE1->getOpcode() == Instruction::ZExt) {
1067  unsigned DstWidth = CI2->getType()->getBitWidth();
1068  unsigned SrcWidth =
1069  CE1->getOperand(0)->getType()->getPrimitiveSizeInBits();
1070  APInt PossiblySetBits(APInt::getLowBitsSet(DstWidth, SrcWidth));
1071  if ((PossiblySetBits & CI2->getValue()) == PossiblySetBits)
1072  return C1;
1073  }
1074 
1075  // If and'ing the address of a global with a constant, fold it.
1076  if (CE1->getOpcode() == Instruction::PtrToInt &&
1077  isa<GlobalValue>(CE1->getOperand(0))) {
1078  GlobalValue *GV = cast<GlobalValue>(CE1->getOperand(0));
1079 
1080  // Functions are at least 4-byte aligned.
1081  unsigned GVAlign = GV->getAlignment();
1082  if (isa<Function>(GV))
1083  GVAlign = std::max(GVAlign, 4U);
1084 
1085  if (GVAlign > 1) {
1086  unsigned DstWidth = CI2->getType()->getBitWidth();
1087  unsigned SrcWidth = std::min(DstWidth, Log2_32(GVAlign));
1088  APInt BitsNotSet(APInt::getLowBitsSet(DstWidth, SrcWidth));
1089 
1090  // If checking bits we know are clear, return zero.
1091  if ((CI2->getValue() & BitsNotSet) == CI2->getValue())
1092  return Constant::getNullValue(CI2->getType());
1093  }
1094  }
1095  }
1096  break;
1097  case Instruction::Or:
1098  if (CI2->isZero()) return C1; // X | 0 == X
1099  if (CI2->isMinusOne())
1100  return C2; // X | -1 == -1
1101  break;
1102  case Instruction::Xor:
1103  if (CI2->isZero()) return C1; // X ^ 0 == X
1104 
1105  if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1106  switch (CE1->getOpcode()) {
1107  default: break;
1108  case Instruction::ICmp:
1109  case Instruction::FCmp:
1110  // cmp pred ^ true -> cmp !pred
1111  assert(CI2->isOne());
1112  CmpInst::Predicate pred = (CmpInst::Predicate)CE1->getPredicate();
1113  pred = CmpInst::getInversePredicate(pred);
1114  return ConstantExpr::getCompare(pred, CE1->getOperand(0),
1115  CE1->getOperand(1));
1116  }
1117  }
1118  break;
1119  case Instruction::AShr:
1120  // ashr (zext C to Ty), C2 -> lshr (zext C, CSA), C2
1121  if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1))
1122  if (CE1->getOpcode() == Instruction::ZExt) // Top bits known zero.
1123  return ConstantExpr::getLShr(C1, C2);
1124  break;
1125  }
1126  } else if (isa<ConstantInt>(C1)) {
1127  // If C1 is a ConstantInt and C2 is not, swap the operands.
1128  if (Instruction::isCommutative(Opcode))
1129  return ConstantExpr::get(Opcode, C2, C1);
1130  }
1131 
1132  if (ConstantInt *CI1 = dyn_cast<ConstantInt>(C1)) {
1133  if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
1134  const APInt &C1V = CI1->getValue();
1135  const APInt &C2V = CI2->getValue();
1136  switch (Opcode) {
1137  default:
1138  break;
1139  case Instruction::Add:
1140  return ConstantInt::get(CI1->getContext(), C1V + C2V);
1141  case Instruction::Sub:
1142  return ConstantInt::get(CI1->getContext(), C1V - C2V);
1143  case Instruction::Mul:
1144  return ConstantInt::get(CI1->getContext(), C1V * C2V);
1145  case Instruction::UDiv:
1146  assert(!CI2->isZero() && "Div by zero handled above");
1147  return ConstantInt::get(CI1->getContext(), C1V.udiv(C2V));
1148  case Instruction::SDiv:
1149  assert(!CI2->isZero() && "Div by zero handled above");
1150  if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
1151  return UndefValue::get(CI1->getType()); // MIN_INT / -1 -> undef
1152  return ConstantInt::get(CI1->getContext(), C1V.sdiv(C2V));
1153  case Instruction::URem:
1154  assert(!CI2->isZero() && "Div by zero handled above");
1155  return ConstantInt::get(CI1->getContext(), C1V.urem(C2V));
1156  case Instruction::SRem:
1157  assert(!CI2->isZero() && "Div by zero handled above");
1158  if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
1159  return UndefValue::get(CI1->getType()); // MIN_INT % -1 -> undef
1160  return ConstantInt::get(CI1->getContext(), C1V.srem(C2V));
1161  case Instruction::And:
1162  return ConstantInt::get(CI1->getContext(), C1V & C2V);
1163  case Instruction::Or:
1164  return ConstantInt::get(CI1->getContext(), C1V | C2V);
1165  case Instruction::Xor:
1166  return ConstantInt::get(CI1->getContext(), C1V ^ C2V);
1167  case Instruction::Shl:
1168  if (C2V.ult(C1V.getBitWidth()))
1169  return ConstantInt::get(CI1->getContext(), C1V.shl(C2V));
1170  return UndefValue::get(C1->getType()); // too big shift is undef
1171  case Instruction::LShr:
1172  if (C2V.ult(C1V.getBitWidth()))
1173  return ConstantInt::get(CI1->getContext(), C1V.lshr(C2V));
1174  return UndefValue::get(C1->getType()); // too big shift is undef
1175  case Instruction::AShr:
1176  if (C2V.ult(C1V.getBitWidth()))
1177  return ConstantInt::get(CI1->getContext(), C1V.ashr(C2V));
1178  return UndefValue::get(C1->getType()); // too big shift is undef
1179  }
1180  }
1181 
1182  switch (Opcode) {
1183  case Instruction::SDiv:
1184  case Instruction::UDiv:
1185  case Instruction::URem:
1186  case Instruction::SRem:
1187  case Instruction::LShr:
1188  case Instruction::AShr:
1189  case Instruction::Shl:
1190  if (CI1->isZero()) return C1;
1191  break;
1192  default:
1193  break;
1194  }
1195  } else if (ConstantFP *CFP1 = dyn_cast<ConstantFP>(C1)) {
1196  if (ConstantFP *CFP2 = dyn_cast<ConstantFP>(C2)) {
1197  const APFloat &C1V = CFP1->getValueAPF();
1198  const APFloat &C2V = CFP2->getValueAPF();
1199  APFloat C3V = C1V; // copy for modification
1200  switch (Opcode) {
1201  default:
1202  break;
1203  case Instruction::FAdd:
1204  (void)C3V.add(C2V, APFloat::rmNearestTiesToEven);
1205  return ConstantFP::get(C1->getContext(), C3V);
1206  case Instruction::FSub:
1207  (void)C3V.subtract(C2V, APFloat::rmNearestTiesToEven);
1208  return ConstantFP::get(C1->getContext(), C3V);
1209  case Instruction::FMul:
1210  (void)C3V.multiply(C2V, APFloat::rmNearestTiesToEven);
1211  return ConstantFP::get(C1->getContext(), C3V);
1212  case Instruction::FDiv:
1213  (void)C3V.divide(C2V, APFloat::rmNearestTiesToEven);
1214  return ConstantFP::get(C1->getContext(), C3V);
1215  case Instruction::FRem:
1216  (void)C3V.mod(C2V);
1217  return ConstantFP::get(C1->getContext(), C3V);
1218  }
1219  }
1220  } else if (VectorType *VTy = dyn_cast<VectorType>(C1->getType())) {
1221  // Fold each element and create a vector constant from those constants.
1223  Type *Ty = IntegerType::get(VTy->getContext(), 32);
1224  for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1225  Constant *ExtractIdx = ConstantInt::get(Ty, i);
1226  Constant *LHS = ConstantExpr::getExtractElement(C1, ExtractIdx);
1227  Constant *RHS = ConstantExpr::getExtractElement(C2, ExtractIdx);
1228 
1229  // If any element of a divisor vector is zero, the whole op is undef.
1230  if (Instruction::isIntDivRem(Opcode) && RHS->isNullValue())
1231  return UndefValue::get(VTy);
1232 
1233  Result.push_back(ConstantExpr::get(Opcode, LHS, RHS));
1234  }
1235 
1236  return ConstantVector::get(Result);
1237  }
1238 
1239  if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1240  // There are many possible foldings we could do here. We should probably
1241  // at least fold add of a pointer with an integer into the appropriate
1242  // getelementptr. This will improve alias analysis a bit.
1243 
1244  // Given ((a + b) + c), if (b + c) folds to something interesting, return
1245  // (a + (b + c)).
1246  if (Instruction::isAssociative(Opcode) && CE1->getOpcode() == Opcode) {
1247  Constant *T = ConstantExpr::get(Opcode, CE1->getOperand(1), C2);
1248  if (!isa<ConstantExpr>(T) || cast<ConstantExpr>(T)->getOpcode() != Opcode)
1249  return ConstantExpr::get(Opcode, CE1->getOperand(0), T);
1250  }
1251  } else if (isa<ConstantExpr>(C2)) {
1252  // If C2 is a constant expr and C1 isn't, flop them around and fold the
1253  // other way if possible.
1254  if (Instruction::isCommutative(Opcode))
1255  return ConstantFoldBinaryInstruction(Opcode, C2, C1);
1256  }
1257 
1258  // i1 can be simplified in many cases.
1259  if (C1->getType()->isIntegerTy(1)) {
1260  switch (Opcode) {
1261  case Instruction::Add:
1262  case Instruction::Sub:
1263  return ConstantExpr::getXor(C1, C2);
1264  case Instruction::Mul:
1265  return ConstantExpr::getAnd(C1, C2);
1266  case Instruction::Shl:
1267  case Instruction::LShr:
1268  case Instruction::AShr:
1269  // We can assume that C2 == 0. If it were one the result would be
1270  // undefined because the shift value is as large as the bitwidth.
1271  return C1;
1272  case Instruction::SDiv:
1273  case Instruction::UDiv:
1274  // We can assume that C2 == 1. If it were zero the result would be
1275  // undefined through division by zero.
1276  return C1;
1277  case Instruction::URem:
1278  case Instruction::SRem:
1279  // We can assume that C2 == 1. If it were zero the result would be
1280  // undefined through division by zero.
1281  return ConstantInt::getFalse(C1->getContext());
1282  default:
1283  break;
1284  }
1285  }
1286 
1287  // We don't know how to fold this.
1288  return nullptr;
1289 }
1290 
1291 /// This type is zero-sized if it's an array or structure of zero-sized types.
1292 /// The only leaf zero-sized type is an empty structure.
1293 static bool isMaybeZeroSizedType(Type *Ty) {
1294  if (StructType *STy = dyn_cast<StructType>(Ty)) {
1295  if (STy->isOpaque()) return true; // Can't say.
1296 
1297  // If all of elements have zero size, this does too.
1298  for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
1299  if (!isMaybeZeroSizedType(STy->getElementType(i))) return false;
1300  return true;
1301 
1302  } else if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
1303  return isMaybeZeroSizedType(ATy->getElementType());
1304  }
1305  return false;
1306 }
1307 
1308 /// Compare the two constants as though they were getelementptr indices.
1309 /// This allows coercion of the types to be the same thing.
1310 ///
1311 /// If the two constants are the "same" (after coercion), return 0. If the
1312 /// first is less than the second, return -1, if the second is less than the
1313 /// first, return 1. If the constants are not integral, return -2.
1314 ///
1315 static int IdxCompare(Constant *C1, Constant *C2, Type *ElTy) {
1316  if (C1 == C2) return 0;
1317 
1318  // Ok, we found a different index. If they are not ConstantInt, we can't do
1319  // anything with them.
1320  if (!isa<ConstantInt>(C1) || !isa<ConstantInt>(C2))
1321  return -2; // don't know!
1322 
1323  // We cannot compare the indices if they don't fit in an int64_t.
1324  if (cast<ConstantInt>(C1)->getValue().getActiveBits() > 64 ||
1325  cast<ConstantInt>(C2)->getValue().getActiveBits() > 64)
1326  return -2; // don't know!
1327 
1328  // Ok, we have two differing integer indices. Sign extend them to be the same
1329  // type.
1330  int64_t C1Val = cast<ConstantInt>(C1)->getSExtValue();
1331  int64_t C2Val = cast<ConstantInt>(C2)->getSExtValue();
1332 
1333  if (C1Val == C2Val) return 0; // They are equal
1334 
1335  // If the type being indexed over is really just a zero sized type, there is
1336  // no pointer difference being made here.
1337  if (isMaybeZeroSizedType(ElTy))
1338  return -2; // dunno.
1339 
1340  // If they are really different, now that they are the same type, then we
1341  // found a difference!
1342  if (C1Val < C2Val)
1343  return -1;
1344  else
1345  return 1;
1346 }
1347 
1348 /// This function determines if there is anything we can decide about the two
1349 /// constants provided. This doesn't need to handle simple things like
1350 /// ConstantFP comparisons, but should instead handle ConstantExprs.
1351 /// If we can determine that the two constants have a particular relation to
1352 /// each other, we should return the corresponding FCmpInst predicate,
1353 /// otherwise return FCmpInst::BAD_FCMP_PREDICATE. This is used below in
1354 /// ConstantFoldCompareInstruction.
1355 ///
1356 /// To simplify this code we canonicalize the relation so that the first
1357 /// operand is always the most "complex" of the two. We consider ConstantFP
1358 /// to be the simplest, and ConstantExprs to be the most complex.
1360  assert(V1->getType() == V2->getType() &&
1361  "Cannot compare values of different types!");
1362 
1363  // Handle degenerate case quickly
1364  if (V1 == V2) return FCmpInst::FCMP_OEQ;
1365 
1366  if (!isa<ConstantExpr>(V1)) {
1367  if (!isa<ConstantExpr>(V2)) {
1368  // Simple case, use the standard constant folder.
1369  ConstantInt *R = nullptr;
1370  R = dyn_cast<ConstantInt>(
1372  if (R && !R->isZero())
1373  return FCmpInst::FCMP_OEQ;
1374  R = dyn_cast<ConstantInt>(
1376  if (R && !R->isZero())
1377  return FCmpInst::FCMP_OLT;
1378  R = dyn_cast<ConstantInt>(
1380  if (R && !R->isZero())
1381  return FCmpInst::FCMP_OGT;
1382 
1383  // Nothing more we can do
1385  }
1386 
1387  // If the first operand is simple and second is ConstantExpr, swap operands.
1388  FCmpInst::Predicate SwappedRelation = evaluateFCmpRelation(V2, V1);
1389  if (SwappedRelation != FCmpInst::BAD_FCMP_PREDICATE)
1390  return FCmpInst::getSwappedPredicate(SwappedRelation);
1391  } else {
1392  // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1393  // constantexpr or a simple constant.
1394  ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1395  switch (CE1->getOpcode()) {
1396  case Instruction::FPTrunc:
1397  case Instruction::FPExt:
1398  case Instruction::UIToFP:
1399  case Instruction::SIToFP:
1400  // We might be able to do something with these but we don't right now.
1401  break;
1402  default:
1403  break;
1404  }
1405  }
1406  // There are MANY other foldings that we could perform here. They will
1407  // probably be added on demand, as they seem needed.
1409 }
1410 
1412  const GlobalValue *GV2) {
1413  auto isGlobalUnsafeForEquality = [](const GlobalValue *GV) {
1414  if (GV->hasExternalWeakLinkage() || GV->hasWeakAnyLinkage())
1415  return true;
1416  if (const auto *GVar = dyn_cast<GlobalVariable>(GV)) {
1417  Type *Ty = GVar->getValueType();
1418  // A global with opaque type might end up being zero sized.
1419  if (!Ty->isSized())
1420  return true;
1421  // A global with an empty type might lie at the address of any other
1422  // global.
1423  if (Ty->isEmptyTy())
1424  return true;
1425  }
1426  return false;
1427  };
1428  // Don't try to decide equality of aliases.
1429  if (!isa<GlobalAlias>(GV1) && !isa<GlobalAlias>(GV2))
1430  if (!isGlobalUnsafeForEquality(GV1) && !isGlobalUnsafeForEquality(GV2))
1431  return ICmpInst::ICMP_NE;
1433 }
1434 
1435 /// This function determines if there is anything we can decide about the two
1436 /// constants provided. This doesn't need to handle simple things like integer
1437 /// comparisons, but should instead handle ConstantExprs and GlobalValues.
1438 /// If we can determine that the two constants have a particular relation to
1439 /// each other, we should return the corresponding ICmp predicate, otherwise
1440 /// return ICmpInst::BAD_ICMP_PREDICATE.
1441 ///
1442 /// To simplify this code we canonicalize the relation so that the first
1443 /// operand is always the most "complex" of the two. We consider simple
1444 /// constants (like ConstantInt) to be the simplest, followed by
1445 /// GlobalValues, followed by ConstantExpr's (the most complex).
1446 ///
1448  bool isSigned) {
1449  assert(V1->getType() == V2->getType() &&
1450  "Cannot compare different types of values!");
1451  if (V1 == V2) return ICmpInst::ICMP_EQ;
1452 
1453  if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1) &&
1454  !isa<BlockAddress>(V1)) {
1455  if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2) &&
1456  !isa<BlockAddress>(V2)) {
1457  // We distilled this down to a simple case, use the standard constant
1458  // folder.
1459  ConstantInt *R = nullptr;
1461  R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1462  if (R && !R->isZero())
1463  return pred;
1464  pred = isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1465  R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1466  if (R && !R->isZero())
1467  return pred;
1468  pred = isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1469  R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1470  if (R && !R->isZero())
1471  return pred;
1472 
1473  // If we couldn't figure it out, bail.
1475  }
1476 
1477  // If the first operand is simple, swap operands.
1478  ICmpInst::Predicate SwappedRelation =
1479  evaluateICmpRelation(V2, V1, isSigned);
1480  if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1481  return ICmpInst::getSwappedPredicate(SwappedRelation);
1482 
1483  } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1)) {
1484  if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1485  ICmpInst::Predicate SwappedRelation =
1486  evaluateICmpRelation(V2, V1, isSigned);
1487  if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1488  return ICmpInst::getSwappedPredicate(SwappedRelation);
1490  }
1491 
1492  // Now we know that the RHS is a GlobalValue, BlockAddress or simple
1493  // constant (which, since the types must match, means that it's a
1494  // ConstantPointerNull).
1495  if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
1496  return areGlobalsPotentiallyEqual(GV, GV2);
1497  } else if (isa<BlockAddress>(V2)) {
1498  return ICmpInst::ICMP_NE; // Globals never equal labels.
1499  } else {
1500  assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!");
1501  // GlobalVals can never be null unless they have external weak linkage.
1502  // We don't try to evaluate aliases here.
1503  // NOTE: We should not be doing this constant folding if null pointer
1504  // is considered valid for the function. But currently there is no way to
1505  // query it from the Constant type.
1506  if (!GV->hasExternalWeakLinkage() && !isa<GlobalAlias>(GV) &&
1507  !NullPointerIsDefined(nullptr /* F */,
1508  GV->getType()->getAddressSpace()))
1509  return ICmpInst::ICMP_NE;
1510  }
1511  } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(V1)) {
1512  if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1513  ICmpInst::Predicate SwappedRelation =
1514  evaluateICmpRelation(V2, V1, isSigned);
1515  if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1516  return ICmpInst::getSwappedPredicate(SwappedRelation);
1518  }
1519 
1520  // Now we know that the RHS is a GlobalValue, BlockAddress or simple
1521  // constant (which, since the types must match, means that it is a
1522  // ConstantPointerNull).
1523  if (const BlockAddress *BA2 = dyn_cast<BlockAddress>(V2)) {
1524  // Block address in another function can't equal this one, but block
1525  // addresses in the current function might be the same if blocks are
1526  // empty.
1527  if (BA2->getFunction() != BA->getFunction())
1528  return ICmpInst::ICMP_NE;
1529  } else {
1530  // Block addresses aren't null, don't equal the address of globals.
1531  assert((isa<ConstantPointerNull>(V2) || isa<GlobalValue>(V2)) &&
1532  "Canonicalization guarantee!");
1533  return ICmpInst::ICMP_NE;
1534  }
1535  } else {
1536  // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1537  // constantexpr, a global, block address, or a simple constant.
1538  ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1539  Constant *CE1Op0 = CE1->getOperand(0);
1540 
1541  switch (CE1->getOpcode()) {
1542  case Instruction::Trunc:
1543  case Instruction::FPTrunc:
1544  case Instruction::FPExt:
1545  case Instruction::FPToUI:
1546  case Instruction::FPToSI:
1547  break; // We can't evaluate floating point casts or truncations.
1548 
1549  case Instruction::UIToFP:
1550  case Instruction::SIToFP:
1551  case Instruction::BitCast:
1552  case Instruction::ZExt:
1553  case Instruction::SExt:
1554  // We can't evaluate floating point casts or truncations.
1555  if (CE1Op0->getType()->isFloatingPointTy())
1556  break;
1557 
1558  // If the cast is not actually changing bits, and the second operand is a
1559  // null pointer, do the comparison with the pre-casted value.
1560  if (V2->isNullValue() && CE1->getType()->isIntOrPtrTy()) {
1561  if (CE1->getOpcode() == Instruction::ZExt) isSigned = false;
1562  if (CE1->getOpcode() == Instruction::SExt) isSigned = true;
1563  return evaluateICmpRelation(CE1Op0,
1564  Constant::getNullValue(CE1Op0->getType()),
1565  isSigned);
1566  }
1567  break;
1568 
1569  case Instruction::GetElementPtr: {
1570  GEPOperator *CE1GEP = cast<GEPOperator>(CE1);
1571  // Ok, since this is a getelementptr, we know that the constant has a
1572  // pointer type. Check the various cases.
1573  if (isa<ConstantPointerNull>(V2)) {
1574  // If we are comparing a GEP to a null pointer, check to see if the base
1575  // of the GEP equals the null pointer.
1576  if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1577  if (GV->hasExternalWeakLinkage())
1578  // Weak linkage GVals could be zero or not. We're comparing that
1579  // to null pointer so its greater-or-equal
1580  return isSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE;
1581  else
1582  // If its not weak linkage, the GVal must have a non-zero address
1583  // so the result is greater-than
1584  return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1585  } else if (isa<ConstantPointerNull>(CE1Op0)) {
1586  // If we are indexing from a null pointer, check to see if we have any
1587  // non-zero indices.
1588  for (unsigned i = 1, e = CE1->getNumOperands(); i != e; ++i)
1589  if (!CE1->getOperand(i)->isNullValue())
1590  // Offsetting from null, must not be equal.
1591  return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1592  // Only zero indexes from null, must still be zero.
1593  return ICmpInst::ICMP_EQ;
1594  }
1595  // Otherwise, we can't really say if the first operand is null or not.
1596  } else if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
1597  if (isa<ConstantPointerNull>(CE1Op0)) {
1598  if (GV2->hasExternalWeakLinkage())
1599  // Weak linkage GVals could be zero or not. We're comparing it to
1600  // a null pointer, so its less-or-equal
1601  return isSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE;
1602  else
1603  // If its not weak linkage, the GVal must have a non-zero address
1604  // so the result is less-than
1605  return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1606  } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1607  if (GV == GV2) {
1608  // If this is a getelementptr of the same global, then it must be
1609  // different. Because the types must match, the getelementptr could
1610  // only have at most one index, and because we fold getelementptr's
1611  // with a single zero index, it must be nonzero.
1612  assert(CE1->getNumOperands() == 2 &&
1613  !CE1->getOperand(1)->isNullValue() &&
1614  "Surprising getelementptr!");
1615  return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1616  } else {
1617  if (CE1GEP->hasAllZeroIndices())
1618  return areGlobalsPotentiallyEqual(GV, GV2);
1620  }
1621  }
1622  } else {
1623  ConstantExpr *CE2 = cast<ConstantExpr>(V2);
1624  Constant *CE2Op0 = CE2->getOperand(0);
1625 
1626  // There are MANY other foldings that we could perform here. They will
1627  // probably be added on demand, as they seem needed.
1628  switch (CE2->getOpcode()) {
1629  default: break;
1630  case Instruction::GetElementPtr:
1631  // By far the most common case to handle is when the base pointers are
1632  // obviously to the same global.
1633  if (isa<GlobalValue>(CE1Op0) && isa<GlobalValue>(CE2Op0)) {
1634  // Don't know relative ordering, but check for inequality.
1635  if (CE1Op0 != CE2Op0) {
1636  GEPOperator *CE2GEP = cast<GEPOperator>(CE2);
1637  if (CE1GEP->hasAllZeroIndices() && CE2GEP->hasAllZeroIndices())
1638  return areGlobalsPotentiallyEqual(cast<GlobalValue>(CE1Op0),
1639  cast<GlobalValue>(CE2Op0));
1641  }
1642  // Ok, we know that both getelementptr instructions are based on the
1643  // same global. From this, we can precisely determine the relative
1644  // ordering of the resultant pointers.
1645  unsigned i = 1;
1646 
1647  // The logic below assumes that the result of the comparison
1648  // can be determined by finding the first index that differs.
1649  // This doesn't work if there is over-indexing in any
1650  // subsequent indices, so check for that case first.
1651  if (!CE1->isGEPWithNoNotionalOverIndexing() ||
1653  return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1654 
1655  // Compare all of the operands the GEP's have in common.
1656  gep_type_iterator GTI = gep_type_begin(CE1);
1657  for (;i != CE1->getNumOperands() && i != CE2->getNumOperands();
1658  ++i, ++GTI)
1659  switch (IdxCompare(CE1->getOperand(i),
1660  CE2->getOperand(i), GTI.getIndexedType())) {
1661  case -1: return isSigned ? ICmpInst::ICMP_SLT:ICmpInst::ICMP_ULT;
1662  case 1: return isSigned ? ICmpInst::ICMP_SGT:ICmpInst::ICMP_UGT;
1663  case -2: return ICmpInst::BAD_ICMP_PREDICATE;
1664  }
1665 
1666  // Ok, we ran out of things they have in common. If any leftovers
1667  // are non-zero then we have a difference, otherwise we are equal.
1668  for (; i < CE1->getNumOperands(); ++i)
1669  if (!CE1->getOperand(i)->isNullValue()) {
1670  if (isa<ConstantInt>(CE1->getOperand(i)))
1671  return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1672  else
1673  return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1674  }
1675 
1676  for (; i < CE2->getNumOperands(); ++i)
1677  if (!CE2->getOperand(i)->isNullValue()) {
1678  if (isa<ConstantInt>(CE2->getOperand(i)))
1679  return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1680  else
1681  return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1682  }
1683  return ICmpInst::ICMP_EQ;
1684  }
1685  }
1686  }
1687  break;
1688  }
1689  default:
1690  break;
1691  }
1692  }
1693 
1695 }
1696 
1698  Constant *C1, Constant *C2) {
1699  Type *ResultTy;
1700  if (VectorType *VT = dyn_cast<VectorType>(C1->getType()))
1701  ResultTy = VectorType::get(Type::getInt1Ty(C1->getContext()),
1702  VT->getNumElements());
1703  else
1704  ResultTy = Type::getInt1Ty(C1->getContext());
1705 
1706  // Fold FCMP_FALSE/FCMP_TRUE unconditionally.
1707  if (pred == FCmpInst::FCMP_FALSE)
1708  return Constant::getNullValue(ResultTy);
1709 
1710  if (pred == FCmpInst::FCMP_TRUE)
1711  return Constant::getAllOnesValue(ResultTy);
1712 
1713  // Handle some degenerate cases first
1714  if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
1716  bool isIntegerPredicate = ICmpInst::isIntPredicate(Predicate);
1717  // For EQ and NE, we can always pick a value for the undef to make the
1718  // predicate pass or fail, so we can return undef.
1719  // Also, if both operands are undef, we can return undef for int comparison.
1720  if (ICmpInst::isEquality(Predicate) || (isIntegerPredicate && C1 == C2))
1721  return UndefValue::get(ResultTy);
1722 
1723  // Otherwise, for integer compare, pick the same value as the non-undef
1724  // operand, and fold it to true or false.
1725  if (isIntegerPredicate)
1726  return ConstantInt::get(ResultTy, CmpInst::isTrueWhenEqual(Predicate));
1727 
1728  // Choosing NaN for the undef will always make unordered comparison succeed
1729  // and ordered comparison fails.
1730  return ConstantInt::get(ResultTy, CmpInst::isUnordered(Predicate));
1731  }
1732 
1733  // icmp eq/ne(null,GV) -> false/true
1734  if (C1->isNullValue()) {
1735  if (const GlobalValue *GV = dyn_cast<GlobalValue>(C2))
1736  // Don't try to evaluate aliases. External weak GV can be null.
1737  if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage() &&
1738  !NullPointerIsDefined(nullptr /* F */,
1739  GV->getType()->getAddressSpace())) {
1740  if (pred == ICmpInst::ICMP_EQ)
1741  return ConstantInt::getFalse(C1->getContext());
1742  else if (pred == ICmpInst::ICMP_NE)
1743  return ConstantInt::getTrue(C1->getContext());
1744  }
1745  // icmp eq/ne(GV,null) -> false/true
1746  } else if (C2->isNullValue()) {
1747  if (const GlobalValue *GV = dyn_cast<GlobalValue>(C1))
1748  // Don't try to evaluate aliases. External weak GV can be null.
1749  if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage() &&
1750  !NullPointerIsDefined(nullptr /* F */,
1751  GV->getType()->getAddressSpace())) {
1752  if (pred == ICmpInst::ICMP_EQ)
1753  return ConstantInt::getFalse(C1->getContext());
1754  else if (pred == ICmpInst::ICMP_NE)
1755  return ConstantInt::getTrue(C1->getContext());
1756  }
1757  }
1758 
1759  // If the comparison is a comparison between two i1's, simplify it.
1760  if (C1->getType()->isIntegerTy(1)) {
1761  switch(pred) {
1762  case ICmpInst::ICMP_EQ:
1763  if (isa<ConstantInt>(C2))
1766  case ICmpInst::ICMP_NE:
1767  return ConstantExpr::getXor(C1, C2);
1768  default:
1769  break;
1770  }
1771  }
1772 
1773  if (isa<ConstantInt>(C1) && isa<ConstantInt>(C2)) {
1774  const APInt &V1 = cast<ConstantInt>(C1)->getValue();
1775  const APInt &V2 = cast<ConstantInt>(C2)->getValue();
1776  switch (pred) {
1777  default: llvm_unreachable("Invalid ICmp Predicate");
1778  case ICmpInst::ICMP_EQ: return ConstantInt::get(ResultTy, V1 == V2);
1779  case ICmpInst::ICMP_NE: return ConstantInt::get(ResultTy, V1 != V2);
1780  case ICmpInst::ICMP_SLT: return ConstantInt::get(ResultTy, V1.slt(V2));
1781  case ICmpInst::ICMP_SGT: return ConstantInt::get(ResultTy, V1.sgt(V2));
1782  case ICmpInst::ICMP_SLE: return ConstantInt::get(ResultTy, V1.sle(V2));
1783  case ICmpInst::ICMP_SGE: return ConstantInt::get(ResultTy, V1.sge(V2));
1784  case ICmpInst::ICMP_ULT: return ConstantInt::get(ResultTy, V1.ult(V2));
1785  case ICmpInst::ICMP_UGT: return ConstantInt::get(ResultTy, V1.ugt(V2));
1786  case ICmpInst::ICMP_ULE: return ConstantInt::get(ResultTy, V1.ule(V2));
1787  case ICmpInst::ICMP_UGE: return ConstantInt::get(ResultTy, V1.uge(V2));
1788  }
1789  } else if (isa<ConstantFP>(C1) && isa<ConstantFP>(C2)) {
1790  const APFloat &C1V = cast<ConstantFP>(C1)->getValueAPF();
1791  const APFloat &C2V = cast<ConstantFP>(C2)->getValueAPF();
1792  APFloat::cmpResult R = C1V.compare(C2V);
1793  switch (pred) {
1794  default: llvm_unreachable("Invalid FCmp Predicate");
1795  case FCmpInst::FCMP_FALSE: return Constant::getNullValue(ResultTy);
1796  case FCmpInst::FCMP_TRUE: return Constant::getAllOnesValue(ResultTy);
1797  case FCmpInst::FCMP_UNO:
1798  return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered);
1799  case FCmpInst::FCMP_ORD:
1800  return ConstantInt::get(ResultTy, R!=APFloat::cmpUnordered);
1801  case FCmpInst::FCMP_UEQ:
1802  return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1803  R==APFloat::cmpEqual);
1804  case FCmpInst::FCMP_OEQ:
1805  return ConstantInt::get(ResultTy, R==APFloat::cmpEqual);
1806  case FCmpInst::FCMP_UNE:
1807  return ConstantInt::get(ResultTy, R!=APFloat::cmpEqual);
1808  case FCmpInst::FCMP_ONE:
1809  return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
1811  case FCmpInst::FCMP_ULT:
1812  return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1814  case FCmpInst::FCMP_OLT:
1815  return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan);
1816  case FCmpInst::FCMP_UGT:
1817  return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1819  case FCmpInst::FCMP_OGT:
1820  return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan);
1821  case FCmpInst::FCMP_ULE:
1822  return ConstantInt::get(ResultTy, R!=APFloat::cmpGreaterThan);
1823  case FCmpInst::FCMP_OLE:
1824  return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
1825  R==APFloat::cmpEqual);
1826  case FCmpInst::FCMP_UGE:
1827  return ConstantInt::get(ResultTy, R!=APFloat::cmpLessThan);
1828  case FCmpInst::FCMP_OGE:
1829  return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan ||
1830  R==APFloat::cmpEqual);
1831  }
1832  } else if (C1->getType()->isVectorTy()) {
1833  // If we can constant fold the comparison of each element, constant fold
1834  // the whole vector comparison.
1835  SmallVector<Constant*, 4> ResElts;
1836  Type *Ty = IntegerType::get(C1->getContext(), 32);
1837  // Compare the elements, producing an i1 result or constant expr.
1838  for (unsigned i = 0, e = C1->getType()->getVectorNumElements(); i != e;++i){
1839  Constant *C1E =
1841  Constant *C2E =
1843 
1844  ResElts.push_back(ConstantExpr::getCompare(pred, C1E, C2E));
1845  }
1846 
1847  return ConstantVector::get(ResElts);
1848  }
1849 
1850  if (C1->getType()->isFloatingPointTy() &&
1851  // Only call evaluateFCmpRelation if we have a constant expr to avoid
1852  // infinite recursive loop
1853  (isa<ConstantExpr>(C1) || isa<ConstantExpr>(C2))) {
1854  int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
1855  switch (evaluateFCmpRelation(C1, C2)) {
1856  default: llvm_unreachable("Unknown relation!");
1857  case FCmpInst::FCMP_UNO:
1858  case FCmpInst::FCMP_ORD:
1859  case FCmpInst::FCMP_UEQ:
1860  case FCmpInst::FCMP_UNE:
1861  case FCmpInst::FCMP_ULT:
1862  case FCmpInst::FCMP_UGT:
1863  case FCmpInst::FCMP_ULE:
1864  case FCmpInst::FCMP_UGE:
1865  case FCmpInst::FCMP_TRUE:
1866  case FCmpInst::FCMP_FALSE:
1868  break; // Couldn't determine anything about these constants.
1869  case FCmpInst::FCMP_OEQ: // We know that C1 == C2
1870  Result = (pred == FCmpInst::FCMP_UEQ || pred == FCmpInst::FCMP_OEQ ||
1871  pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE ||
1872  pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
1873  break;
1874  case FCmpInst::FCMP_OLT: // We know that C1 < C2
1875  Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
1876  pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT ||
1877  pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE);
1878  break;
1879  case FCmpInst::FCMP_OGT: // We know that C1 > C2
1880  Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
1881  pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT ||
1882  pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
1883  break;
1884  case FCmpInst::FCMP_OLE: // We know that C1 <= C2
1885  // We can only partially decide this relation.
1886  if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
1887  Result = 0;
1888  else if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
1889  Result = 1;
1890  break;
1891  case FCmpInst::FCMP_OGE: // We known that C1 >= C2
1892  // We can only partially decide this relation.
1893  if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
1894  Result = 0;
1895  else if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
1896  Result = 1;
1897  break;
1898  case FCmpInst::FCMP_ONE: // We know that C1 != C2
1899  // We can only partially decide this relation.
1900  if (pred == FCmpInst::FCMP_OEQ || pred == FCmpInst::FCMP_UEQ)
1901  Result = 0;
1902  else if (pred == FCmpInst::FCMP_ONE || pred == FCmpInst::FCMP_UNE)
1903  Result = 1;
1904  break;
1905  }
1906 
1907  // If we evaluated the result, return it now.
1908  if (Result != -1)
1909  return ConstantInt::get(ResultTy, Result);
1910 
1911  } else {
1912  // Evaluate the relation between the two constants, per the predicate.
1913  int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
1914  switch (evaluateICmpRelation(C1, C2,
1916  default: llvm_unreachable("Unknown relational!");
1918  break; // Couldn't determine anything about these constants.
1919  case ICmpInst::ICMP_EQ: // We know the constants are equal!
1920  // If we know the constants are equal, we can decide the result of this
1921  // computation precisely.
1923  break;
1924  case ICmpInst::ICMP_ULT:
1925  switch (pred) {
1927  Result = 1; break;
1929  Result = 0; break;
1930  }
1931  break;
1932  case ICmpInst::ICMP_SLT:
1933  switch (pred) {
1935  Result = 1; break;
1937  Result = 0; break;
1938  }
1939  break;
1940  case ICmpInst::ICMP_UGT:
1941  switch (pred) {
1943  Result = 1; break;
1945  Result = 0; break;
1946  }
1947  break;
1948  case ICmpInst::ICMP_SGT:
1949  switch (pred) {
1951  Result = 1; break;
1953  Result = 0; break;
1954  }
1955  break;
1956  case ICmpInst::ICMP_ULE:
1957  if (pred == ICmpInst::ICMP_UGT) Result = 0;
1958  if (pred == ICmpInst::ICMP_ULT || pred == ICmpInst::ICMP_ULE) Result = 1;
1959  break;
1960  case ICmpInst::ICMP_SLE:
1961  if (pred == ICmpInst::ICMP_SGT) Result = 0;
1962  if (pred == ICmpInst::ICMP_SLT || pred == ICmpInst::ICMP_SLE) Result = 1;
1963  break;
1964  case ICmpInst::ICMP_UGE:
1965  if (pred == ICmpInst::ICMP_ULT) Result = 0;
1966  if (pred == ICmpInst::ICMP_UGT || pred == ICmpInst::ICMP_UGE) Result = 1;
1967  break;
1968  case ICmpInst::ICMP_SGE:
1969  if (pred == ICmpInst::ICMP_SLT) Result = 0;
1970  if (pred == ICmpInst::ICMP_SGT || pred == ICmpInst::ICMP_SGE) Result = 1;
1971  break;
1972  case ICmpInst::ICMP_NE:
1973  if (pred == ICmpInst::ICMP_EQ) Result = 0;
1974  if (pred == ICmpInst::ICMP_NE) Result = 1;
1975  break;
1976  }
1977 
1978  // If we evaluated the result, return it now.
1979  if (Result != -1)
1980  return ConstantInt::get(ResultTy, Result);
1981 
1982  // If the right hand side is a bitcast, try using its inverse to simplify
1983  // it by moving it to the left hand side. We can't do this if it would turn
1984  // a vector compare into a scalar compare or visa versa.
1985  if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(C2)) {
1986  Constant *CE2Op0 = CE2->getOperand(0);
1987  if (CE2->getOpcode() == Instruction::BitCast &&
1988  CE2->getType()->isVectorTy() == CE2Op0->getType()->isVectorTy()) {
1990  return ConstantExpr::getICmp(pred, Inverse, CE2Op0);
1991  }
1992  }
1993 
1994  // If the left hand side is an extension, try eliminating it.
1995  if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1996  if ((CE1->getOpcode() == Instruction::SExt &&
1998  (CE1->getOpcode() == Instruction::ZExt &&
2000  Constant *CE1Op0 = CE1->getOperand(0);
2001  Constant *CE1Inverse = ConstantExpr::getTrunc(CE1, CE1Op0->getType());
2002  if (CE1Inverse == CE1Op0) {
2003  // Check whether we can safely truncate the right hand side.
2004  Constant *C2Inverse = ConstantExpr::getTrunc(C2, CE1Op0->getType());
2005  if (ConstantExpr::getCast(CE1->getOpcode(), C2Inverse,
2006  C2->getType()) == C2)
2007  return ConstantExpr::getICmp(pred, CE1Inverse, C2Inverse);
2008  }
2009  }
2010  }
2011 
2012  if ((!isa<ConstantExpr>(C1) && isa<ConstantExpr>(C2)) ||
2013  (C1->isNullValue() && !C2->isNullValue())) {
2014  // If C2 is a constant expr and C1 isn't, flip them around and fold the
2015  // other way if possible.
2016  // Also, if C1 is null and C2 isn't, flip them around.
2018  return ConstantExpr::getICmp(pred, C2, C1);
2019  }
2020  }
2021  return nullptr;
2022 }
2023 
2024 /// Test whether the given sequence of *normalized* indices is "inbounds".
2025 template<typename IndexTy>
2027  // No indices means nothing that could be out of bounds.
2028  if (Idxs.empty()) return true;
2029 
2030  // If the first index is zero, it's in bounds.
2031  if (cast<Constant>(Idxs[0])->isNullValue()) return true;
2032 
2033  // If the first index is one and all the rest are zero, it's in bounds,
2034  // by the one-past-the-end rule.
2035  if (auto *CI = dyn_cast<ConstantInt>(Idxs[0])) {
2036  if (!CI->isOne())
2037  return false;
2038  } else {
2039  auto *CV = cast<ConstantDataVector>(Idxs[0]);
2040  CI = dyn_cast_or_null<ConstantInt>(CV->getSplatValue());
2041  if (!CI || !CI->isOne())
2042  return false;
2043  }
2044 
2045  for (unsigned i = 1, e = Idxs.size(); i != e; ++i)
2046  if (!cast<Constant>(Idxs[i])->isNullValue())
2047  return false;
2048  return true;
2049 }
2050 
2051 /// Test whether a given ConstantInt is in-range for a SequentialType.
2052 static bool isIndexInRangeOfArrayType(uint64_t NumElements,
2053  const ConstantInt *CI) {
2054  // We cannot bounds check the index if it doesn't fit in an int64_t.
2055  if (CI->getValue().getActiveBits() > 64)
2056  return false;
2057 
2058  // A negative index or an index past the end of our sequential type is
2059  // considered out-of-range.
2060  int64_t IndexVal = CI->getSExtValue();
2061  if (IndexVal < 0 || (NumElements > 0 && (uint64_t)IndexVal >= NumElements))
2062  return false;
2063 
2064  // Otherwise, it is in-range.
2065  return true;
2066 }
2067 
2069  bool InBounds,
2070  Optional<unsigned> InRangeIndex,
2071  ArrayRef<Value *> Idxs) {
2072  if (Idxs.empty()) return C;
2073 
2075  C, makeArrayRef((Value *const *)Idxs.data(), Idxs.size()));
2076 
2077  if (isa<UndefValue>(C))
2078  return UndefValue::get(GEPTy);
2079 
2080  Constant *Idx0 = cast<Constant>(Idxs[0]);
2081  if (Idxs.size() == 1 && (Idx0->isNullValue() || isa<UndefValue>(Idx0)))
2082  return GEPTy->isVectorTy() && !C->getType()->isVectorTy()
2084  cast<VectorType>(GEPTy)->getNumElements(), C)
2085  : C;
2086 
2087  if (C->isNullValue()) {
2088  bool isNull = true;
2089  for (unsigned i = 0, e = Idxs.size(); i != e; ++i)
2090  if (!isa<UndefValue>(Idxs[i]) &&
2091  !cast<Constant>(Idxs[i])->isNullValue()) {
2092  isNull = false;
2093  break;
2094  }
2095  if (isNull) {
2096  PointerType *PtrTy = cast<PointerType>(C->getType()->getScalarType());
2097  Type *Ty = GetElementPtrInst::getIndexedType(PointeeTy, Idxs);
2098 
2099  assert(Ty && "Invalid indices for GEP!");
2100  Type *OrigGEPTy = PointerType::get(Ty, PtrTy->getAddressSpace());
2101  Type *GEPTy = PointerType::get(Ty, PtrTy->getAddressSpace());
2102  if (VectorType *VT = dyn_cast<VectorType>(C->getType()))
2103  GEPTy = VectorType::get(OrigGEPTy, VT->getNumElements());
2104 
2105  // The GEP returns a vector of pointers when one of more of
2106  // its arguments is a vector.
2107  for (unsigned i = 0, e = Idxs.size(); i != e; ++i) {
2108  if (auto *VT = dyn_cast<VectorType>(Idxs[i]->getType())) {
2109  GEPTy = VectorType::get(OrigGEPTy, VT->getNumElements());
2110  break;
2111  }
2112  }
2113 
2114  return Constant::getNullValue(GEPTy);
2115  }
2116  }
2117 
2118  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2119  // Combine Indices - If the source pointer to this getelementptr instruction
2120  // is a getelementptr instruction, combine the indices of the two
2121  // getelementptr instructions into a single instruction.
2122  //
2123  if (CE->getOpcode() == Instruction::GetElementPtr) {
2124  gep_type_iterator LastI = gep_type_end(CE);
2125  for (gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
2126  I != E; ++I)
2127  LastI = I;
2128 
2129  // We cannot combine indices if doing so would take us outside of an
2130  // array or vector. Doing otherwise could trick us if we evaluated such a
2131  // GEP as part of a load.
2132  //
2133  // e.g. Consider if the original GEP was:
2134  // i8* getelementptr ({ [2 x i8], i32, i8, [3 x i8] }* @main.c,
2135  // i32 0, i32 0, i64 0)
2136  //
2137  // If we then tried to offset it by '8' to get to the third element,
2138  // an i8, we should *not* get:
2139  // i8* getelementptr ({ [2 x i8], i32, i8, [3 x i8] }* @main.c,
2140  // i32 0, i32 0, i64 8)
2141  //
2142  // This GEP tries to index array element '8 which runs out-of-bounds.
2143  // Subsequent evaluation would get confused and produce erroneous results.
2144  //
2145  // The following prohibits such a GEP from being formed by checking to see
2146  // if the index is in-range with respect to an array.
2147  // TODO: This code may be extended to handle vectors as well.
2148  bool PerformFold = false;
2149  if (Idx0->isNullValue())
2150  PerformFold = true;
2151  else if (LastI.isSequential())
2152  if (ConstantInt *CI = dyn_cast<ConstantInt>(Idx0))
2153  PerformFold = (!LastI.isBoundedSequential() ||
2155  LastI.getSequentialNumElements(), CI)) &&
2156  !CE->getOperand(CE->getNumOperands() - 1)
2157  ->getType()
2158  ->isVectorTy();
2159 
2160  if (PerformFold) {
2161  SmallVector<Value*, 16> NewIndices;
2162  NewIndices.reserve(Idxs.size() + CE->getNumOperands());
2163  NewIndices.append(CE->op_begin() + 1, CE->op_end() - 1);
2164 
2165  // Add the last index of the source with the first index of the new GEP.
2166  // Make sure to handle the case when they are actually different types.
2167  Constant *Combined = CE->getOperand(CE->getNumOperands()-1);
2168  // Otherwise it must be an array.
2169  if (!Idx0->isNullValue()) {
2170  Type *IdxTy = Combined->getType();
2171  if (IdxTy != Idx0->getType()) {
2172  unsigned CommonExtendedWidth =
2173  std::max(IdxTy->getIntegerBitWidth(),
2174  Idx0->getType()->getIntegerBitWidth());
2175  CommonExtendedWidth = std::max(CommonExtendedWidth, 64U);
2176 
2177  Type *CommonTy =
2178  Type::getIntNTy(IdxTy->getContext(), CommonExtendedWidth);
2179  Constant *C1 = ConstantExpr::getSExtOrBitCast(Idx0, CommonTy);
2180  Constant *C2 = ConstantExpr::getSExtOrBitCast(Combined, CommonTy);
2181  Combined = ConstantExpr::get(Instruction::Add, C1, C2);
2182  } else {
2183  Combined =
2184  ConstantExpr::get(Instruction::Add, Idx0, Combined);
2185  }
2186  }
2187 
2188  NewIndices.push_back(Combined);
2189  NewIndices.append(Idxs.begin() + 1, Idxs.end());
2190 
2191  // The combined GEP normally inherits its index inrange attribute from
2192  // the inner GEP, but if the inner GEP's last index was adjusted by the
2193  // outer GEP, any inbounds attribute on that index is invalidated.
2194  Optional<unsigned> IRIndex = cast<GEPOperator>(CE)->getInRangeIndex();
2195  if (IRIndex && *IRIndex == CE->getNumOperands() - 2 && !Idx0->isNullValue())
2196  IRIndex = None;
2197 
2199  cast<GEPOperator>(CE)->getSourceElementType(), CE->getOperand(0),
2200  NewIndices, InBounds && cast<GEPOperator>(CE)->isInBounds(),
2201  IRIndex);
2202  }
2203  }
2204 
2205  // Attempt to fold casts to the same type away. For example, folding:
2206  //
2207  // i32* getelementptr ([2 x i32]* bitcast ([3 x i32]* %X to [2 x i32]*),
2208  // i64 0, i64 0)
2209  // into:
2210  //
2211  // i32* getelementptr ([3 x i32]* %X, i64 0, i64 0)
2212  //
2213  // Don't fold if the cast is changing address spaces.
2214  if (CE->isCast() && Idxs.size() > 1 && Idx0->isNullValue()) {
2215  PointerType *SrcPtrTy =
2216  dyn_cast<PointerType>(CE->getOperand(0)->getType());
2217  PointerType *DstPtrTy = dyn_cast<PointerType>(CE->getType());
2218  if (SrcPtrTy && DstPtrTy) {
2219  ArrayType *SrcArrayTy =
2220  dyn_cast<ArrayType>(SrcPtrTy->getElementType());
2221  ArrayType *DstArrayTy =
2222  dyn_cast<ArrayType>(DstPtrTy->getElementType());
2223  if (SrcArrayTy && DstArrayTy
2224  && SrcArrayTy->getElementType() == DstArrayTy->getElementType()
2225  && SrcPtrTy->getAddressSpace() == DstPtrTy->getAddressSpace())
2226  return ConstantExpr::getGetElementPtr(SrcArrayTy,
2227  (Constant *)CE->getOperand(0),
2228  Idxs, InBounds, InRangeIndex);
2229  }
2230  }
2231  }
2232 
2233  // Check to see if any array indices are not within the corresponding
2234  // notional array or vector bounds. If so, try to determine if they can be
2235  // factored out into preceding dimensions.
2237  Type *Ty = PointeeTy;
2238  Type *Prev = C->getType();
2239  bool Unknown =
2240  !isa<ConstantInt>(Idxs[0]) && !isa<ConstantDataVector>(Idxs[0]);
2241  for (unsigned i = 1, e = Idxs.size(); i != e;
2242  Prev = Ty, Ty = cast<CompositeType>(Ty)->getTypeAtIndex(Idxs[i]), ++i) {
2243  if (!isa<ConstantInt>(Idxs[i]) && !isa<ConstantDataVector>(Idxs[i])) {
2244  // We don't know if it's in range or not.
2245  Unknown = true;
2246  continue;
2247  }
2248  if (!isa<ConstantInt>(Idxs[i - 1]) && !isa<ConstantDataVector>(Idxs[i - 1]))
2249  // Skip if the type of the previous index is not supported.
2250  continue;
2251  if (InRangeIndex && i == *InRangeIndex + 1) {
2252  // If an index is marked inrange, we cannot apply this canonicalization to
2253  // the following index, as that will cause the inrange index to point to
2254  // the wrong element.
2255  continue;
2256  }
2257  if (isa<StructType>(Ty)) {
2258  // The verify makes sure that GEPs into a struct are in range.
2259  continue;
2260  }
2261  auto *STy = cast<SequentialType>(Ty);
2262  if (isa<VectorType>(STy)) {
2263  // There can be awkward padding in after a non-power of two vector.
2264  Unknown = true;
2265  continue;
2266  }
2267  if (ConstantInt *CI = dyn_cast<ConstantInt>(Idxs[i])) {
2268  if (isIndexInRangeOfArrayType(STy->getNumElements(), CI))
2269  // It's in range, skip to the next index.
2270  continue;
2271  if (CI->getSExtValue() < 0) {
2272  // It's out of range and negative, don't try to factor it.
2273  Unknown = true;
2274  continue;
2275  }
2276  } else {
2277  auto *CV = cast<ConstantDataVector>(Idxs[i]);
2278  bool InRange = true;
2279  for (unsigned I = 0, E = CV->getNumElements(); I != E; ++I) {
2280  auto *CI = cast<ConstantInt>(CV->getElementAsConstant(I));
2281  InRange &= isIndexInRangeOfArrayType(STy->getNumElements(), CI);
2282  if (CI->getSExtValue() < 0) {
2283  Unknown = true;
2284  break;
2285  }
2286  }
2287  if (InRange || Unknown)
2288  // It's in range, skip to the next index.
2289  // It's out of range and negative, don't try to factor it.
2290  continue;
2291  }
2292  if (isa<StructType>(Prev)) {
2293  // It's out of range, but the prior dimension is a struct
2294  // so we can't do anything about it.
2295  Unknown = true;
2296  continue;
2297  }
2298  // It's out of range, but we can factor it into the prior
2299  // dimension.
2300  NewIdxs.resize(Idxs.size());
2301  // Determine the number of elements in our sequential type.
2302  uint64_t NumElements = STy->getArrayNumElements();
2303 
2304  // Expand the current index or the previous index to a vector from a scalar
2305  // if necessary.
2306  Constant *CurrIdx = cast<Constant>(Idxs[i]);
2307  auto *PrevIdx =
2308  NewIdxs[i - 1] ? NewIdxs[i - 1] : cast<Constant>(Idxs[i - 1]);
2309  bool IsCurrIdxVector = CurrIdx->getType()->isVectorTy();
2310  bool IsPrevIdxVector = PrevIdx->getType()->isVectorTy();
2311  bool UseVector = IsCurrIdxVector || IsPrevIdxVector;
2312 
2313  if (!IsCurrIdxVector && IsPrevIdxVector)
2314  CurrIdx = ConstantDataVector::getSplat(
2315  PrevIdx->getType()->getVectorNumElements(), CurrIdx);
2316 
2317  if (!IsPrevIdxVector && IsCurrIdxVector)
2318  PrevIdx = ConstantDataVector::getSplat(
2319  CurrIdx->getType()->getVectorNumElements(), PrevIdx);
2320 
2321  Constant *Factor =
2322  ConstantInt::get(CurrIdx->getType()->getScalarType(), NumElements);
2323  if (UseVector)
2325  IsPrevIdxVector ? PrevIdx->getType()->getVectorNumElements()
2326  : CurrIdx->getType()->getVectorNumElements(),
2327  Factor);
2328 
2329  NewIdxs[i] = ConstantExpr::getSRem(CurrIdx, Factor);
2330 
2331  Constant *Div = ConstantExpr::getSDiv(CurrIdx, Factor);
2332 
2333  unsigned CommonExtendedWidth =
2334  std::max(PrevIdx->getType()->getScalarSizeInBits(),
2335  Div->getType()->getScalarSizeInBits());
2336  CommonExtendedWidth = std::max(CommonExtendedWidth, 64U);
2337 
2338  // Before adding, extend both operands to i64 to avoid
2339  // overflow trouble.
2340  Type *ExtendedTy = Type::getIntNTy(Div->getContext(), CommonExtendedWidth);
2341  if (UseVector)
2342  ExtendedTy = VectorType::get(
2343  ExtendedTy, IsPrevIdxVector
2344  ? PrevIdx->getType()->getVectorNumElements()
2345  : CurrIdx->getType()->getVectorNumElements());
2346 
2347  if (!PrevIdx->getType()->isIntOrIntVectorTy(CommonExtendedWidth))
2348  PrevIdx = ConstantExpr::getSExt(PrevIdx, ExtendedTy);
2349 
2350  if (!Div->getType()->isIntOrIntVectorTy(CommonExtendedWidth))
2351  Div = ConstantExpr::getSExt(Div, ExtendedTy);
2352 
2353  NewIdxs[i - 1] = ConstantExpr::getAdd(PrevIdx, Div);
2354  }
2355 
2356  // If we did any factoring, start over with the adjusted indices.
2357  if (!NewIdxs.empty()) {
2358  for (unsigned i = 0, e = Idxs.size(); i != e; ++i)
2359  if (!NewIdxs[i]) NewIdxs[i] = cast<Constant>(Idxs[i]);
2360  return ConstantExpr::getGetElementPtr(PointeeTy, C, NewIdxs, InBounds,
2361  InRangeIndex);
2362  }
2363 
2364  // If all indices are known integers and normalized, we can do a simple
2365  // check for the "inbounds" property.
2366  if (!Unknown && !InBounds)
2367  if (auto *GV = dyn_cast<GlobalVariable>(C))
2368  if (!GV->hasExternalWeakLinkage() && isInBoundsIndices(Idxs))
2369  return ConstantExpr::getGetElementPtr(PointeeTy, C, Idxs,
2370  /*InBounds=*/true, InRangeIndex);
2371 
2372  return nullptr;
2373 }
static unsigned getBitWidth(Type *Ty, const DataLayout &DL)
Returns the bitwidth of the given scalar or pointer type.
Type * getVectorElementType() const
Definition: Type.h:371
uint64_t CallInst * C
static const fltSemantics & IEEEquad() LLVM_READNONE
Definition: APFloat.cpp:126
static Constant * FoldBitCast(Constant *V, Type *DestTy)
static ConstantInt * getFalse(LLVMContext &Context)
Definition: Constants.cpp:584
class_match< UndefValue > m_Undef()
Match an arbitrary undef constant.
Definition: PatternMatch.h:88
bool isAllOnesValue() const
Return true if this is the value that would be returned by getAllOnesValue.
Definition: Constants.cpp:100
static IntegerType * getInt1Ty(LLVMContext &C)
Definition: Type.cpp:173
opStatus convertFromAPInt(const APInt &Input, bool IsSigned, roundingMode RM)
Definition: APFloat.h:1077
unsigned getOpcode() const
Return the opcode at the root of this constant expression.
Definition: Constants.h:1199
GCNRegPressure max(const GCNRegPressure &P1, const GCNRegPressure &P2)
is_zero m_Zero()
Match any null constant or a vector with all elements equal to 0.
Definition: PatternMatch.h:373
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
static Constant * getNaN(Type *Ty, bool Negative=false, unsigned type=0)
Definition: Constants.cpp:725
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:1143
bool isSized(SmallPtrSetImpl< Type *> *Visited=nullptr) const
Return true if it makes sense to take the size of this type.
Definition: Type.h:265
iterator begin() const
Definition: ArrayRef.h:137
#define LLVM_FALLTHROUGH
Definition: Compiler.h:86
APInt sdiv(const APInt &RHS) const
Signed division function for APInt.
Definition: APInt.cpp:1591
bool isFP128Ty() const
Return true if this is &#39;fp128&#39;.
Definition: Type.h:156
Constant * ConstantFoldExtractElementInstruction(Constant *Val, Constant *Idx)
Attempt to constant fold an extractelement instruction with the specified operands and indices...
bool slt(const APInt &RHS) const
Signed less than comparison.
Definition: APInt.h:1198
APInt udiv(const APInt &RHS) const
Unsigned division operation.
Definition: APInt.cpp:1520
static APInt getLowBitsSet(unsigned numBits, unsigned loBitsSet)
Get a value with low bits set.
Definition: APInt.h:648
static Constant * getFoldedOffsetOf(Type *Ty, Constant *FieldNo, Type *DestTy, bool Folded)
Return a ConstantExpr with type DestTy for offsetof on Ty and FieldNo, with any known factors factore...
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
gep_type_iterator gep_type_end(const User *GEP)
unsigned less or equal
Definition: InstrTypes.h:711
unsigned less than
Definition: InstrTypes.h:710
Constant * ConstantFoldCastInstruction(unsigned opcode, Constant *V, Type *DestTy)
static Constant * getExtractElement(Constant *Vec, Constant *Idx, Type *OnlyIfReducedTy=nullptr)
Definition: Constants.cpp:2051
0 1 0 0 True if ordered and less than
Definition: InstrTypes.h:691
LLVMContext & getContext() const
All values hold a context through their type.
Definition: Value.cpp:714
1 1 1 0 True if unordered or not equal
Definition: InstrTypes.h:701
bool sgt(const APInt &RHS) const
Signed greather than comparison.
Definition: APInt.h:1268
APInt trunc(unsigned width) const
Truncate to new width.
Definition: APInt.cpp:811
static IntegerType * getInt64Ty(LLVMContext &C)
Definition: Type.cpp:177
static Constant * getCompare(unsigned short pred, Constant *C1, Constant *C2, bool OnlyIfReduced=false)
Return an ICmp or FCmp comparison operator constant expression.
Definition: Constants.cpp:1903
bool isVectorTy() const
True if this is an instance of VectorType.
Definition: Type.h:230
static Constant * getFoldedAlignOf(Type *Ty, Type *DestTy, bool Folded)
Return a ConstantExpr with type DestTy for alignof on Ty, with any known factors factored out...
void reserve(size_type N)
Definition: SmallVector.h:376
bool sle(const APInt &RHS) const
Signed less or equal comparison.
Definition: APInt.h:1233
bool isPPC_FP128Ty() const
Return true if this is powerpc long double.
Definition: Type.h:159
static Constant * get(ArrayType *T, ArrayRef< Constant *> V)
Definition: Constants.cpp:960
unsigned getBitWidth() const
Return the number of bits in the APInt.
Definition: APInt.h:1503
LLVMContext & getContext() const
Return the LLVMContext in which this type was uniqued.
Definition: Type.h:130
static Constant * getNullValue(Type *Ty)
Constructor to create a &#39;0&#39; constant of arbitrary type.
Definition: Constants.cpp:268
static Constant * getAdd(Constant *C1, Constant *C2, bool HasNUW=false, bool HasNSW=false)
Definition: Constants.cpp:2186
opStatus convertToInteger(MutableArrayRef< integerPart > Input, unsigned int Width, bool IsSigned, roundingMode RM, bool *IsExact) const
Definition: APFloat.h:1069
1 0 0 1 True if unordered or equal
Definition: InstrTypes.h:696
static bool InRange(int64_t Value, unsigned short Shift, int LBound, int HBound)
opStatus divide(const APFloat &RHS, roundingMode RM)
Definition: APFloat.h:968
The address of a basic block.
Definition: Constants.h:836
bool match(Val *V, const Pattern &P)
Definition: PatternMatch.h:49
1 0 0 0 True if unordered: isnan(X) | isnan(Y)
Definition: InstrTypes.h:695
bool isSigned() const
Definition: InstrTypes.h:854
Predicate getInversePredicate() const
For example, EQ -> NE, UGT -> ULE, SLT -> SGE, OEQ -> UNE, UGT -> OLE, OLT -> UGE, etc.
Definition: InstrTypes.h:783
ArrayRef< T > makeArrayRef(const T &OneElt)
Construct an ArrayRef from a single element.
Definition: ArrayRef.h:451
bool isFloatingPointTy() const
Return true if this is one of the six floating-point types.
Definition: Type.h:162
APInt shl(unsigned shiftAmt) const
Left-shift function.
Definition: APInt.h:993
Class to represent struct types.
Definition: DerivedTypes.h:201
static Constant * getLShr(Constant *C1, Constant *C2, bool isExact=false)
Definition: Constants.cpp:2264
static ICmpInst::Predicate evaluateICmpRelation(Constant *V1, Constant *V2, bool isSigned)
This function determines if there is anything we can decide about the two constants provided...
static Constant * BitCastConstantVector(Constant *CV, VectorType *DstTy)
Convert the specified vector Constant node to the specified vector type.
bool isIntegerTy() const
True if this is an instance of IntegerType.
Definition: Type.h:197
0 1 0 1 True if ordered and less than or equal
Definition: InstrTypes.h:692
static Constant * getSExt(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1628
uint64_t getNumElements() const
Definition: DerivedTypes.h:359
void lshrInPlace(unsigned ShiftAmt)
Logical right-shift this APInt by ShiftAmt in place.
Definition: APInt.h:978
unsigned getActiveBits() const
Compute the number of active bits in the value.
Definition: APInt.h:1527
bool isOne() const
This is just a convenience method to make client code smaller for a common case.
Definition: Constants.h:201
static Constant * get(unsigned Opcode, Constant *C1, Constant *C2, unsigned Flags=0, Type *OnlyIfReducedTy=nullptr)
get - Return a binary or shift operator constant expression, folding if possible. ...
Definition: Constants.cpp:1783
static Constant * getSizeOf(Type *Ty)
getSizeOf constant expr - computes the (alloc) size of a type (in address-units, not bits) in a targe...
Definition: Constants.cpp:1862
bool isNullValue() const
Return true if this is the value that would be returned by getNullValue.
Definition: Constants.cpp:85
A constant value that is initialized with an expression using other constant values.
Definition: Constants.h:885
static unsigned foldConstantCastPair(unsigned opc, ConstantExpr *Op, Type *DstTy)
This function determines which opcode to use to fold two constant cast expressions together...
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:245
bool isFirstClassType() const
Return true if the type is "first class", meaning it is a valid type for a Value. ...
Definition: Type.h:244
opStatus convert(const fltSemantics &ToSemantics, roundingMode RM, bool *losesInfo)
Definition: APFloat.cpp:4444
static int IdxCompare(Constant *C1, Constant *C2, Type *ElTy)
Compare the two constants as though they were getelementptr indices.
#define T
Class to represent array types.
Definition: DerivedTypes.h:369
static Constant * getSelect(Constant *C, Constant *V1, Constant *V2, Type *OnlyIfReducedTy=nullptr)
Select constant expr.
Definition: Constants.cpp:1925
bool isIntOrPtrTy() const
Return true if this is an integer type or a pointer type.
Definition: Type.h:212
const APInt & getValue() const
Return the constant as an APInt value reference.
Definition: Constants.h:138
bool isGEPWithNoNotionalOverIndexing() const
Return true if this is a getelementptr expression and all the index operands are compile-time known i...
Definition: Constants.cpp:1130
opStatus subtract(const APFloat &RHS, roundingMode RM)
Definition: APFloat.h:950
cmpResult
IEEE-754R 5.11: Floating Point Comparison Relations.
Definition: APFloat.h:166
Constant * ConstantFoldInsertValueInstruction(Constant *Agg, Constant *Val, ArrayRef< unsigned > Idxs)
ConstantFoldInsertValueInstruction - Attempt to constant fold an insertvalue instruction with the spe...
bool isIntOrIntVectorTy() const
Return true if this is an integer type or a vector of integer types.
Definition: Type.h:203
static const fltSemantics & IEEEdouble() LLVM_READNONE
Definition: APFloat.cpp:123
unsigned getAlignment() const
Definition: Globals.cpp:97
Value * getOperand(unsigned i) const
Definition: User.h:170
Class to represent pointers.
Definition: DerivedTypes.h:467
Constant * getAggregateElement(unsigned Elt) const
For aggregates (struct/array/vector) return the constant that corresponds to the specified element if...
Definition: Constants.cpp:338
Type * getScalarType() const
If this is a vector type, return the element type, otherwise return &#39;this&#39;.
Definition: Type.h:304
static Constant * getBitCast(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1750
static ICmpInst::Predicate areGlobalsPotentiallyEqual(const GlobalValue *GV1, const GlobalValue *GV2)
bool isFloatTy() const
Return true if this is &#39;float&#39;, a 32-bit IEEE fp type.
Definition: Type.h:147
Constant * ConstantFoldShuffleVectorInstruction(Constant *V1, Constant *V2, Constant *Mask)
Attempt to constant fold a shufflevector instruction with the specified operands and indices...
bool hasAllZeroIndices() const
Return true if all of the indices of this GEP are zeros.
Definition: Operator.h:501
bool isAllOnesValue() const
Determine if all bits are set.
Definition: APInt.h:396
uint64_t getZExtValue() const
Return the constant as a 64-bit unsigned integer value after it has been zero extended as appropriate...
Definition: Constants.h:149
apint_match m_APInt(const APInt *&Res)
Match a ConstantInt or splatted ConstantVector, binding the specified pointer to the contained APInt...
Definition: PatternMatch.h:177
static ConstantPointerNull * get(PointerType *T)
Static factory methods - Return objects of the specified value.
Definition: Constants.cpp:1378
APInt urem(const APInt &RHS) const
Unsigned remainder operation.
Definition: APInt.cpp:1613
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:46
bool ult(const APInt &RHS) const
Unsigned less than comparison.
Definition: APInt.h:1179
size_t size() const
size - Get the array size.
Definition: ArrayRef.h:149
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
This is an important base class in LLVM.
Definition: Constant.h:42
static Constant * getFoldedSizeOf(Type *Ty, Type *DestTy, bool Folded)
Return a ConstantExpr with type DestTy for sizeof on Ty, with any known factors factored out...
This file contains the declarations for the subclasses of Constant, which represent the different fla...
static Constant * getAnd(Constant *C1, Constant *C2)
Definition: Constants.cpp:2245
ConstantFP - Floating Point Values [float, double].
Definition: Constants.h:264
static Constant * getSExtOrBitCast(Constant *C, Type *Ty)
Definition: Constants.cpp:1552
bool isAssociative() const LLVM_READONLY
Return true if the instruction is associative:
bool isMinSignedValue() const
Determine if this is the smallest signed value.
Definition: APInt.h:443
bool isHalfTy() const
Return true if this is &#39;half&#39;, a 16-bit IEEE fp type.
Definition: Type.h:144
Predicate
This enumeration lists the possible predicates for CmpInst subclasses.
Definition: InstrTypes.h:685
bool isBinaryOp() const
Definition: Instruction.h:130
opStatus multiply(const APFloat &RHS, roundingMode RM)
Definition: APFloat.h:959
static Constant * get(StructType *T, ArrayRef< Constant *> V)
Definition: Constants.cpp:1021
0 1 1 1 True if ordered (no nans)
Definition: InstrTypes.h:694
unsigned getAddressSpace() const
Return the address space of the Pointer type.
Definition: DerivedTypes.h:495
bool isX86_MMXTy() const
Return true if this is X86 MMX.
Definition: Type.h:182
static Constant * getICmp(unsigned short pred, Constant *LHS, Constant *RHS, bool OnlyIfReduced=false)
get* - Return some common constants without having to specify the full Instruction::OPCODE identifier...
Definition: Constants.cpp:2001
static const fltSemantics & x87DoubleExtended() LLVM_READNONE
Definition: APFloat.cpp:129
Class to represent integer types.
Definition: DerivedTypes.h:40
Constant Vector Declarations.
Definition: Constants.h:496
static Constant * getSplat(unsigned NumElts, Constant *Elt)
Return a ConstantVector with the specified constant in each element.
Definition: Constants.cpp:2586
static Constant * getNot(Constant *C)
Definition: Constants.cpp:2180
static Constant * getAllOnesValue(Type *Ty)
Definition: Constants.cpp:322
1 1 1 1 Always true (always folded)
Definition: InstrTypes.h:702
static UndefValue * get(Type *T)
Static factory methods - Return an &#39;undef&#39; object of the specified type.
Definition: Constants.cpp:1392
bool isCast() const
Definition: Instruction.h:133
size_t size() const
Definition: SmallVector.h:53
static wasm::ValType getType(const TargetRegisterClass *RC)
Constant * ConstantFoldBinaryInstruction(unsigned Opcode, Constant *V1, Constant *V2)
static int getMaskValue(const Constant *Mask, unsigned Elt)
Return the shuffle mask value for the specified element of the mask.
1 1 0 1 True if unordered, less than, or equal
Definition: InstrTypes.h:700
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
const T * data() const
Definition: ArrayRef.h:146
APInt lshr(unsigned shiftAmt) const
Logical right-shift function.
Definition: APInt.h:971
signed greater than
Definition: InstrTypes.h:712
hexagon gen pred
static Constant * getFCmp(unsigned short pred, Constant *LHS, Constant *RHS, bool OnlyIfReduced=false)
Definition: Constants.cpp:2026
This is the superclass of the array and vector type classes.
Definition: DerivedTypes.h:343
0 0 1 0 True if ordered and greater than
Definition: InstrTypes.h:689
static Constant * getPointerCast(Constant *C, Type *Ty)
Create a BitCast, AddrSpaceCast, or a PtrToInt cast constant expression.
Definition: Constants.cpp:1564
APInt ashr(unsigned ShiftAmt) const
Arithmetic right-shift function.
Definition: APInt.h:947
static Constant * getSplat(unsigned NumElts, Constant *Elt)
Return a ConstantVector with the specified constant in each element.
Definition: Constants.cpp:1096
static IntegerType * get(LLVMContext &C, unsigned NumBits)
This static method is the primary way of constructing an IntegerType.
Definition: Type.cpp:240
static const fltSemantics & IEEEsingle() LLVM_READNONE
Definition: APFloat.cpp:120
static Constant * ExtractConstantBytes(Constant *C, unsigned ByteStart, unsigned ByteSize)
V is an integer constant which only has a subset of its bytes used.
unsigned getNumOperands() const
Definition: User.h:192
static bool isIndexInRangeOfArrayType(uint64_t NumElements, const ConstantInt *CI)
Test whether a given ConstantInt is in-range for a SequentialType.
This is the shared class of boolean and integer constants.
Definition: Constants.h:84
static const fltSemantics & IEEEhalf() LLVM_READNONE
Definition: APFloat.cpp:117
static Constant * getSDiv(Constant *C1, Constant *C2, bool isExact=false)
Definition: Constants.cpp:2224
unsigned getScalarSizeInBits() const LLVM_READONLY
If this is a vector type, return the getPrimitiveSizeInBits value for the element type...
Definition: Type.cpp:130
1 1 0 0 True if unordered or less than
Definition: InstrTypes.h:699
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:847
Predicate
Predicate - These are "(BI << 5) | BO" for various predicates.
Definition: PPCPredicates.h:27
iterator end() const
Definition: ArrayRef.h:138
static Constant * getNUWMul(Constant *C1, Constant *C2)
Definition: Constants.h:993
signed less than
Definition: InstrTypes.h:714
static IntegerType * getIntNTy(LLVMContext &C, unsigned N)
Definition: Type.cpp:180
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:1614
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:621
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:684
bool uge(const APInt &RHS) const
Unsigned greater or equal comparison.
Definition: APInt.h:1287
static bool isMaybeZeroSizedType(Type *Ty)
This type is zero-sized if it&#39;s an array or structure of zero-sized types.
static ConstantInt * getTrue(LLVMContext &Context)
Definition: Constants.cpp:577
bool NullPointerIsDefined(const Function *F, unsigned AS=0)
Check whether null pointer dereferencing is considered undefined behavior for a given function or an ...
Definition: Function.cpp:1440
bool isCommutative() const
Return true if the instruction is commutative:
Definition: Instruction.h:474
unsigned Log2_32(uint32_t Value)
Return the floor log base 2 of the specified value, -1 if the value is zero.
Definition: MathExtras.h:539
unsigned getVectorNumElements() const
Definition: DerivedTypes.h:462
bool isIntPredicate() const
Definition: InstrTypes.h:777
bool isTrueWhenEqual() const
This is just a convenience.
Definition: InstrTypes.h:879
signed less or equal
Definition: InstrTypes.h:715
Class to represent vector types.
Definition: DerivedTypes.h:393
Class for arbitrary precision integers.
Definition: APInt.h:70
bool ule(const APInt &RHS) const
Unsigned less or equal comparison.
Definition: APInt.h:1217
bool sge(const APInt &RHS) const
Signed greater or equal comparison.
Definition: APInt.h:1303
static Constant * getCast(unsigned ops, Constant *C, Type *Ty, bool OnlyIfReduced=false)
Convenience function for getting a Cast operation.
Definition: Constants.cpp:1507
opStatus mod(const APFloat &RHS)
Definition: APFloat.h:986
ArrayRef< T > slice(size_t N, size_t M) const
slice(n, m) - Chop off the first N elements of the array, and keep M elements in the array...
Definition: ArrayRef.h:179
void append(in_iter in_start, in_iter in_end)
Add the specified range to the end of the SmallVector.
Definition: SmallVector.h:394
bool isX86_FP80Ty() const
Return true if this is x86 long double.
Definition: Type.h:153
static const fltSemantics & PPCDoubleDouble() LLVM_READNONE
Definition: APFloat.cpp:135
Constant * ConstantFoldCompareInstruction(unsigned short predicate, Constant *C1, Constant *C2)
opStatus add(const APFloat &RHS, roundingMode RM)
Definition: APFloat.h:941
bool ugt(const APInt &RHS) const
Unsigned greather than comparison.
Definition: APInt.h:1249
Constant * ConstantFoldSelectInstruction(Constant *Cond, Constant *V1, Constant *V2)
Attempt to constant fold a select instruction with the specified operands.
static Type * getIndexedType(Type *Ty, ArrayRef< Value *> IdxList)
Returns the type of the element that would be loaded with a load instruction with the specified param...
static IntegerType * getInt32Ty(LLVMContext &C)
Definition: Type.cpp:176
unsigned getIntegerBitWidth() const
Definition: DerivedTypes.h:97
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:56
static Constant * getOffsetOf(StructType *STy, unsigned FieldNo)
getOffsetOf constant expr - computes the offset of a struct field in a target independent way (Note: ...
Definition: Constants.cpp:1885
unsigned greater or equal
Definition: InstrTypes.h:709
static bool isUnordered(Predicate predicate)
Determine if the predicate is an unordered operation.
static bool isInBoundsIndices(ArrayRef< IndexTy > Idxs)
Test whether the given sequence of normalized indices is "inbounds".
APInt srem(const APInt &RHS) const
Function for signed remainder operation.
Definition: APInt.cpp:1683
static Constant * getInBoundsGetElementPtr(Type *Ty, Constant *C, ArrayRef< Constant *> IdxList)
Create an "inbounds" getelementptr.
Definition: Constants.h:1170
bool isEquality() const
Return true if this predicate is either EQ or NE.
static Instruction::CastOps getCastOpcode(const Value *Val, bool SrcIsSigned, Type *Ty, bool DstIsSigned)
Returns the opcode necessary to cast Val into Ty using usual casting rules.
#define I(x, y, z)
Definition: MD5.cpp:58
#define N
static Constant * getOr(Constant *C1, Constant *C2)
Definition: Constants.cpp:2249
static const fltSemantics & Bogus() LLVM_READNONE
A Pseudo fltsemantic used to construct APFloats that cannot conflict with anything real...
Definition: APFloat.cpp:132
bool isZero() const
This is just a convenience method to make client code smaller for a common code.
Definition: Constants.h:193
Constant * ConstantFoldInsertElementInstruction(Constant *Val, Constant *Elt, Constant *Idx)
Attempt to constant fold an insertelement instruction with the specified operands and indices...
0 1 1 0 True if ordered and operands are unequal
Definition: InstrTypes.h:693
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
1 0 1 0 True if unordered or greater than
Definition: InstrTypes.h:697
Constant * ConstantFoldGetElementPtr(Type *Ty, Constant *C, bool InBounds, Optional< unsigned > InRangeIndex, ArrayRef< Value *> Idxs)
static Type * getGEPReturnType(Value *Ptr, ArrayRef< Value *> IdxList)
Returns the pointer type returned by the GEP instruction, which may be a vector of pointers...
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
static Constant * getSRem(Constant *C1, Constant *C2)
Definition: Constants.cpp:2237
unsigned getPrimitiveSizeInBits() const LLVM_READONLY
Return the basic size of this type if it is a primitive type.
Definition: Type.cpp:115
0 0 0 1 True if ordered and equal
Definition: InstrTypes.h:688
LLVM Value Representation.
Definition: Value.h:73
1 0 1 1 True if unordered, greater than, or equal
Definition: InstrTypes.h:698
cst_pred_ty< is_one > m_One()
Match an integer 1 or a vector with all elements equal to 1.
Definition: PatternMatch.h:352
static VectorType * get(Type *ElementType, unsigned NumElements)
This static method is the primary way to construct an VectorType.
Definition: Type.cpp:593
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
bool isCast() const
Return true if this is a convert constant expression.
Definition: Constants.cpp:1122
Type * getElementType() const
Definition: DerivedTypes.h:360
unsigned greater than
Definition: InstrTypes.h:708
bool isIntDivRem() const
Definition: Instruction.h:131
Predicate getSwappedPredicate() const
For example, EQ->EQ, SLE->SGE, ULT->UGT, OEQ->OEQ, ULE->UGE, OLT->OGT, etc.
Definition: InstrTypes.h:799
Type * getSourceElementType() const
Definition: Operator.cpp:23
Constant * ConstantFoldExtractValueInstruction(Constant *Agg, ArrayRef< unsigned > Idxs)
Attempt to constant fold an extractvalue instruction with the specified operands and indices...
bool isEmptyTy() const
Return true if this type is empty, that is, it has no elements or all of its elements are empty...
Definition: Type.cpp:98
static APInt getNullValue(unsigned numBits)
Get the &#39;0&#39; value.
Definition: APInt.h:569
int64_t getSExtValue() const
Return the constant as a 64-bit integer value after it has been sign extended as appropriate for the ...
Definition: Constants.h:157
static Constant * getAlignOf(Type *Ty)
getAlignOf constant expr - computes the alignment of a type in a target independent way (Note: the re...
Definition: Constants.cpp:1872
static Constant * getMul(Constant *C1, Constant *C2, bool HasNUW=false, bool HasNSW=false)
Definition: Constants.cpp:2208
0 0 1 1 True if ordered and greater than or equal
Definition: InstrTypes.h:690
bool isDoubleTy() const
Return true if this is &#39;double&#39;, a 64-bit IEEE fp type.
Definition: Type.h:150
static Constant * get(ArrayRef< Constant *> V)
Definition: Constants.cpp:1056
Type * getElementType() const
Definition: DerivedTypes.h:486
static FCmpInst::Predicate evaluateFCmpRelation(Constant *V1, Constant *V2)
This function determines if there is anything we can decide about the two constants provided...
0 0 0 0 Always false (always folded)
Definition: InstrTypes.h:687
signed greater or equal
Definition: InstrTypes.h:713
bool empty() const
empty - Check if the array is empty.
Definition: ArrayRef.h:144
cmpResult compare(const APFloat &RHS) const
Definition: APFloat.h:1102
static Constant * getXor(Constant *C1, Constant *C2)
Definition: Constants.cpp:2253
const fltSemantics & getFltSemantics() const
Definition: Type.h:169
gep_type_iterator gep_type_begin(const User *GEP)
void resize(size_type N)
Definition: SmallVector.h:351