LLVM  9.0.0svn
ConstantFold.cpp
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1 //===- ConstantFold.cpp - LLVM constant folder ----------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements folding of constants for LLVM. This implements the
10 // (internal) ConstantFold.h interface, which is used by the
11 // ConstantExpr::get* methods to automatically fold constants when possible.
12 //
13 // The current constant folding implementation is implemented in two pieces: the
14 // pieces that don't need DataLayout, and the pieces that do. This is to avoid
15 // a dependence in IR on Target.
16 //
17 //===----------------------------------------------------------------------===//
18 
19 #include "ConstantFold.h"
20 #include "llvm/ADT/APSInt.h"
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/IR/Constants.h"
23 #include "llvm/IR/DerivedTypes.h"
24 #include "llvm/IR/Function.h"
26 #include "llvm/IR/GlobalAlias.h"
27 #include "llvm/IR/GlobalVariable.h"
28 #include "llvm/IR/Instructions.h"
29 #include "llvm/IR/Module.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  APInt ShAmt = Amt->getValue();
272  // Cannot analyze non-byte shifts.
273  if ((ShAmt & 7) != 0)
274  return nullptr;
275  ShAmt.lshrInPlace(3);
276 
277  // If the extract is known to be all zeros, return zero.
278  if (ShAmt.uge(CSize - ByteStart))
279  return Constant::getNullValue(
280  IntegerType::get(CE->getContext(), ByteSize * 8));
281  // If the extract is known to be fully in the input, extract it.
282  if (ShAmt.ule(CSize - (ByteStart + ByteSize)))
283  return ExtractConstantBytes(CE->getOperand(0),
284  ByteStart + ShAmt.getZExtValue(), ByteSize);
285 
286  // TODO: Handle the 'partially zero' case.
287  return nullptr;
288  }
289 
290  case Instruction::Shl: {
291  ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
292  if (!Amt)
293  return nullptr;
294  APInt ShAmt = Amt->getValue();
295  // Cannot analyze non-byte shifts.
296  if ((ShAmt & 7) != 0)
297  return nullptr;
298  ShAmt.lshrInPlace(3);
299 
300  // If the extract is known to be all zeros, return zero.
301  if (ShAmt.uge(ByteStart + ByteSize))
302  return Constant::getNullValue(
303  IntegerType::get(CE->getContext(), ByteSize * 8));
304  // If the extract is known to be fully in the input, extract it.
305  if (ShAmt.ule(ByteStart))
306  return ExtractConstantBytes(CE->getOperand(0),
307  ByteStart - ShAmt.getZExtValue(), ByteSize);
308 
309  // TODO: Handle the 'partially zero' case.
310  return nullptr;
311  }
312 
313  case Instruction::ZExt: {
314  unsigned SrcBitSize =
315  cast<IntegerType>(CE->getOperand(0)->getType())->getBitWidth();
316 
317  // If extracting something that is completely zero, return 0.
318  if (ByteStart*8 >= SrcBitSize)
319  return Constant::getNullValue(IntegerType::get(CE->getContext(),
320  ByteSize*8));
321 
322  // If exactly extracting the input, return it.
323  if (ByteStart == 0 && ByteSize*8 == SrcBitSize)
324  return CE->getOperand(0);
325 
326  // If extracting something completely in the input, if the input is a
327  // multiple of 8 bits, recurse.
328  if ((SrcBitSize&7) == 0 && (ByteStart+ByteSize)*8 <= SrcBitSize)
329  return ExtractConstantBytes(CE->getOperand(0), ByteStart, ByteSize);
330 
331  // Otherwise, if extracting a subset of the input, which is not multiple of
332  // 8 bits, do a shift and trunc to get the bits.
333  if ((ByteStart+ByteSize)*8 < SrcBitSize) {
334  assert((SrcBitSize&7) && "Shouldn't get byte sized case here");
335  Constant *Res = CE->getOperand(0);
336  if (ByteStart)
337  Res = ConstantExpr::getLShr(Res,
338  ConstantInt::get(Res->getType(), ByteStart*8));
340  ByteSize*8));
341  }
342 
343  // TODO: Handle the 'partially zero' case.
344  return nullptr;
345  }
346  }
347 }
348 
349 /// Return a ConstantExpr with type DestTy for sizeof on Ty, with any known
350 /// factors factored out. If Folded is false, return null if no factoring was
351 /// possible, to avoid endlessly bouncing an unfoldable expression back into the
352 /// top-level folder.
353 static Constant *getFoldedSizeOf(Type *Ty, Type *DestTy, bool Folded) {
354  if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
355  Constant *N = ConstantInt::get(DestTy, ATy->getNumElements());
356  Constant *E = getFoldedSizeOf(ATy->getElementType(), DestTy, true);
357  return ConstantExpr::getNUWMul(E, N);
358  }
359 
360  if (StructType *STy = dyn_cast<StructType>(Ty))
361  if (!STy->isPacked()) {
362  unsigned NumElems = STy->getNumElements();
363  // An empty struct has size zero.
364  if (NumElems == 0)
365  return ConstantExpr::getNullValue(DestTy);
366  // Check for a struct with all members having the same size.
367  Constant *MemberSize =
368  getFoldedSizeOf(STy->getElementType(0), DestTy, true);
369  bool AllSame = true;
370  for (unsigned i = 1; i != NumElems; ++i)
371  if (MemberSize !=
372  getFoldedSizeOf(STy->getElementType(i), DestTy, true)) {
373  AllSame = false;
374  break;
375  }
376  if (AllSame) {
377  Constant *N = ConstantInt::get(DestTy, NumElems);
378  return ConstantExpr::getNUWMul(MemberSize, N);
379  }
380  }
381 
382  // Pointer size doesn't depend on the pointee type, so canonicalize them
383  // to an arbitrary pointee.
384  if (PointerType *PTy = dyn_cast<PointerType>(Ty))
385  if (!PTy->getElementType()->isIntegerTy(1))
386  return
387  getFoldedSizeOf(PointerType::get(IntegerType::get(PTy->getContext(), 1),
388  PTy->getAddressSpace()),
389  DestTy, true);
390 
391  // If there's no interesting folding happening, bail so that we don't create
392  // a constant that looks like it needs folding but really doesn't.
393  if (!Folded)
394  return nullptr;
395 
396  // Base case: Get a regular sizeof expression.
399  DestTy, false),
400  C, DestTy);
401  return C;
402 }
403 
404 /// Return a ConstantExpr with type DestTy for alignof on Ty, with any known
405 /// factors factored out. If Folded is false, return null if no factoring was
406 /// possible, to avoid endlessly bouncing an unfoldable expression back into the
407 /// top-level folder.
408 static Constant *getFoldedAlignOf(Type *Ty, Type *DestTy, bool Folded) {
409  // The alignment of an array is equal to the alignment of the
410  // array element. Note that this is not always true for vectors.
411  if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
412  Constant *C = ConstantExpr::getAlignOf(ATy->getElementType());
414  DestTy,
415  false),
416  C, DestTy);
417  return C;
418  }
419 
420  if (StructType *STy = dyn_cast<StructType>(Ty)) {
421  // Packed structs always have an alignment of 1.
422  if (STy->isPacked())
423  return ConstantInt::get(DestTy, 1);
424 
425  // Otherwise, struct alignment is the maximum alignment of any member.
426  // Without target data, we can't compare much, but we can check to see
427  // if all the members have the same alignment.
428  unsigned NumElems = STy->getNumElements();
429  // An empty struct has minimal alignment.
430  if (NumElems == 0)
431  return ConstantInt::get(DestTy, 1);
432  // Check for a struct with all members having the same alignment.
433  Constant *MemberAlign =
434  getFoldedAlignOf(STy->getElementType(0), DestTy, true);
435  bool AllSame = true;
436  for (unsigned i = 1; i != NumElems; ++i)
437  if (MemberAlign != getFoldedAlignOf(STy->getElementType(i), DestTy, true)) {
438  AllSame = false;
439  break;
440  }
441  if (AllSame)
442  return MemberAlign;
443  }
444 
445  // Pointer alignment doesn't depend on the pointee type, so canonicalize them
446  // to an arbitrary pointee.
447  if (PointerType *PTy = dyn_cast<PointerType>(Ty))
448  if (!PTy->getElementType()->isIntegerTy(1))
449  return
451  1),
452  PTy->getAddressSpace()),
453  DestTy, true);
454 
455  // If there's no interesting folding happening, bail so that we don't create
456  // a constant that looks like it needs folding but really doesn't.
457  if (!Folded)
458  return nullptr;
459 
460  // Base case: Get a regular alignof expression.
463  DestTy, false),
464  C, DestTy);
465  return C;
466 }
467 
468 /// Return a ConstantExpr with type DestTy for offsetof on Ty and FieldNo, with
469 /// any known factors factored out. If Folded is false, return null if no
470 /// factoring was possible, to avoid endlessly bouncing an unfoldable expression
471 /// back into the top-level folder.
472 static Constant *getFoldedOffsetOf(Type *Ty, Constant *FieldNo, Type *DestTy,
473  bool Folded) {
474  if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
476  DestTy, false),
477  FieldNo, DestTy);
478  Constant *E = getFoldedSizeOf(ATy->getElementType(), DestTy, true);
479  return ConstantExpr::getNUWMul(E, N);
480  }
481 
482  if (StructType *STy = dyn_cast<StructType>(Ty))
483  if (!STy->isPacked()) {
484  unsigned NumElems = STy->getNumElements();
485  // An empty struct has no members.
486  if (NumElems == 0)
487  return nullptr;
488  // Check for a struct with all members having the same size.
489  Constant *MemberSize =
490  getFoldedSizeOf(STy->getElementType(0), DestTy, true);
491  bool AllSame = true;
492  for (unsigned i = 1; i != NumElems; ++i)
493  if (MemberSize !=
494  getFoldedSizeOf(STy->getElementType(i), DestTy, true)) {
495  AllSame = false;
496  break;
497  }
498  if (AllSame) {
500  false,
501  DestTy,
502  false),
503  FieldNo, DestTy);
504  return ConstantExpr::getNUWMul(MemberSize, N);
505  }
506  }
507 
508  // If there's no interesting folding happening, bail so that we don't create
509  // a constant that looks like it needs folding but really doesn't.
510  if (!Folded)
511  return nullptr;
512 
513  // Base case: Get a regular offsetof expression.
514  Constant *C = ConstantExpr::getOffsetOf(Ty, FieldNo);
516  DestTy, false),
517  C, DestTy);
518  return C;
519 }
520 
522  Type *DestTy) {
523  if (isa<UndefValue>(V)) {
524  // zext(undef) = 0, because the top bits will be zero.
525  // sext(undef) = 0, because the top bits will all be the same.
526  // [us]itofp(undef) = 0, because the result value is bounded.
527  if (opc == Instruction::ZExt || opc == Instruction::SExt ||
528  opc == Instruction::UIToFP || opc == Instruction::SIToFP)
529  return Constant::getNullValue(DestTy);
530  return UndefValue::get(DestTy);
531  }
532 
533  if (V->isNullValue() && !DestTy->isX86_MMXTy() &&
534  opc != Instruction::AddrSpaceCast)
535  return Constant::getNullValue(DestTy);
536 
537  // If the cast operand is a constant expression, there's a few things we can
538  // do to try to simplify it.
539  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
540  if (CE->isCast()) {
541  // Try hard to fold cast of cast because they are often eliminable.
542  if (unsigned newOpc = foldConstantCastPair(opc, CE, DestTy))
543  return ConstantExpr::getCast(newOpc, CE->getOperand(0), DestTy);
544  } else if (CE->getOpcode() == Instruction::GetElementPtr &&
545  // Do not fold addrspacecast (gep 0, .., 0). It might make the
546  // addrspacecast uncanonicalized.
547  opc != Instruction::AddrSpaceCast &&
548  // Do not fold bitcast (gep) with inrange index, as this loses
549  // information.
550  !cast<GEPOperator>(CE)->getInRangeIndex().hasValue() &&
551  // Do not fold if the gep type is a vector, as bitcasting
552  // operand 0 of a vector gep will result in a bitcast between
553  // different sizes.
554  !CE->getType()->isVectorTy()) {
555  // If all of the indexes in the GEP are null values, there is no pointer
556  // adjustment going on. We might as well cast the source pointer.
557  bool isAllNull = true;
558  for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
559  if (!CE->getOperand(i)->isNullValue()) {
560  isAllNull = false;
561  break;
562  }
563  if (isAllNull)
564  // This is casting one pointer type to another, always BitCast
565  return ConstantExpr::getPointerCast(CE->getOperand(0), DestTy);
566  }
567  }
568 
569  // If the cast operand is a constant vector, perform the cast by
570  // operating on each element. In the cast of bitcasts, the element
571  // count may be mismatched; don't attempt to handle that here.
572  if ((isa<ConstantVector>(V) || isa<ConstantDataVector>(V)) &&
573  DestTy->isVectorTy() &&
574  DestTy->getVectorNumElements() == V->getType()->getVectorNumElements()) {
576  VectorType *DestVecTy = cast<VectorType>(DestTy);
577  Type *DstEltTy = DestVecTy->getElementType();
578  Type *Ty = IntegerType::get(V->getContext(), 32);
579  for (unsigned i = 0, e = V->getType()->getVectorNumElements(); i != e; ++i) {
580  Constant *C =
582  res.push_back(ConstantExpr::getCast(opc, C, DstEltTy));
583  }
584  return ConstantVector::get(res);
585  }
586 
587  // We actually have to do a cast now. Perform the cast according to the
588  // opcode specified.
589  switch (opc) {
590  default:
591  llvm_unreachable("Failed to cast constant expression");
592  case Instruction::FPTrunc:
593  case Instruction::FPExt:
594  if (ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
595  bool ignored;
596  APFloat Val = FPC->getValueAPF();
597  Val.convert(DestTy->isHalfTy() ? APFloat::IEEEhalf() :
598  DestTy->isFloatTy() ? APFloat::IEEEsingle() :
599  DestTy->isDoubleTy() ? APFloat::IEEEdouble() :
601  DestTy->isFP128Ty() ? APFloat::IEEEquad() :
603  APFloat::Bogus(),
604  APFloat::rmNearestTiesToEven, &ignored);
605  return ConstantFP::get(V->getContext(), Val);
606  }
607  return nullptr; // Can't fold.
608  case Instruction::FPToUI:
609  case Instruction::FPToSI:
610  if (ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
611  const APFloat &V = FPC->getValueAPF();
612  bool ignored;
613  uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
614  APSInt IntVal(DestBitWidth, opc == Instruction::FPToUI);
615  if (APFloat::opInvalidOp ==
616  V.convertToInteger(IntVal, APFloat::rmTowardZero, &ignored)) {
617  // Undefined behavior invoked - the destination type can't represent
618  // the input constant.
619  return UndefValue::get(DestTy);
620  }
621  return ConstantInt::get(FPC->getContext(), IntVal);
622  }
623  return nullptr; // Can't fold.
624  case Instruction::IntToPtr: //always treated as unsigned
625  if (V->isNullValue()) // Is it an integral null value?
626  return ConstantPointerNull::get(cast<PointerType>(DestTy));
627  return nullptr; // Other pointer types cannot be casted
628  case Instruction::PtrToInt: // always treated as unsigned
629  // Is it a null pointer value?
630  if (V->isNullValue())
631  return ConstantInt::get(DestTy, 0);
632  // If this is a sizeof-like expression, pull out multiplications by
633  // known factors to expose them to subsequent folding. If it's an
634  // alignof-like expression, factor out known factors.
635  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
636  if (CE->getOpcode() == Instruction::GetElementPtr &&
637  CE->getOperand(0)->isNullValue()) {
638  // FIXME: Looks like getFoldedSizeOf(), getFoldedOffsetOf() and
639  // getFoldedAlignOf() don't handle the case when DestTy is a vector of
640  // pointers yet. We end up in asserts in CastInst::getCastOpcode (see
641  // test/Analysis/ConstantFolding/cast-vector.ll). I've only seen this
642  // happen in one "real" C-code test case, so it does not seem to be an
643  // important optimization to handle vectors here. For now, simply bail
644  // out.
645  if (DestTy->isVectorTy())
646  return nullptr;
647  GEPOperator *GEPO = cast<GEPOperator>(CE);
648  Type *Ty = GEPO->getSourceElementType();
649  if (CE->getNumOperands() == 2) {
650  // Handle a sizeof-like expression.
651  Constant *Idx = CE->getOperand(1);
652  bool isOne = isa<ConstantInt>(Idx) && cast<ConstantInt>(Idx)->isOne();
653  if (Constant *C = getFoldedSizeOf(Ty, DestTy, !isOne)) {
655  DestTy, false),
656  Idx, DestTy);
657  return ConstantExpr::getMul(C, Idx);
658  }
659  } else if (CE->getNumOperands() == 3 &&
660  CE->getOperand(1)->isNullValue()) {
661  // Handle an alignof-like expression.
662  if (StructType *STy = dyn_cast<StructType>(Ty))
663  if (!STy->isPacked()) {
664  ConstantInt *CI = cast<ConstantInt>(CE->getOperand(2));
665  if (CI->isOne() &&
666  STy->getNumElements() == 2 &&
667  STy->getElementType(0)->isIntegerTy(1)) {
668  return getFoldedAlignOf(STy->getElementType(1), DestTy, false);
669  }
670  }
671  // Handle an offsetof-like expression.
672  if (Ty->isStructTy() || Ty->isArrayTy()) {
673  if (Constant *C = getFoldedOffsetOf(Ty, CE->getOperand(2),
674  DestTy, false))
675  return C;
676  }
677  }
678  }
679  // Other pointer types cannot be casted
680  return nullptr;
681  case Instruction::UIToFP:
682  case Instruction::SIToFP:
683  if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
684  const APInt &api = CI->getValue();
685  APFloat apf(DestTy->getFltSemantics(),
687  apf.convertFromAPInt(api, opc==Instruction::SIToFP,
689  return ConstantFP::get(V->getContext(), apf);
690  }
691  return nullptr;
692  case Instruction::ZExt:
693  if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
694  uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
695  return ConstantInt::get(V->getContext(),
696  CI->getValue().zext(BitWidth));
697  }
698  return nullptr;
699  case Instruction::SExt:
700  if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
701  uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
702  return ConstantInt::get(V->getContext(),
703  CI->getValue().sext(BitWidth));
704  }
705  return nullptr;
706  case Instruction::Trunc: {
707  if (V->getType()->isVectorTy())
708  return nullptr;
709 
710  uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
711  if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
712  return ConstantInt::get(V->getContext(),
713  CI->getValue().trunc(DestBitWidth));
714  }
715 
716  // The input must be a constantexpr. See if we can simplify this based on
717  // the bytes we are demanding. Only do this if the source and dest are an
718  // even multiple of a byte.
719  if ((DestBitWidth & 7) == 0 &&
720  (cast<IntegerType>(V->getType())->getBitWidth() & 7) == 0)
721  if (Constant *Res = ExtractConstantBytes(V, 0, DestBitWidth / 8))
722  return Res;
723 
724  return nullptr;
725  }
726  case Instruction::BitCast:
727  return FoldBitCast(V, DestTy);
728  case Instruction::AddrSpaceCast:
729  return nullptr;
730  }
731 }
732 
734  Constant *V1, Constant *V2) {
735  // Check for i1 and vector true/false conditions.
736  if (Cond->isNullValue()) return V2;
737  if (Cond->isAllOnesValue()) return V1;
738 
739  // If the condition is a vector constant, fold the result elementwise.
740  if (ConstantVector *CondV = dyn_cast<ConstantVector>(Cond)) {
742  Type *Ty = IntegerType::get(CondV->getContext(), 32);
743  for (unsigned i = 0, e = V1->getType()->getVectorNumElements(); i != e;++i){
744  Constant *V;
746  ConstantInt::get(Ty, i));
748  ConstantInt::get(Ty, i));
749  Constant *Cond = dyn_cast<Constant>(CondV->getOperand(i));
750  if (V1Element == V2Element) {
751  V = V1Element;
752  } else if (isa<UndefValue>(Cond)) {
753  V = isa<UndefValue>(V1Element) ? V1Element : V2Element;
754  } else {
755  if (!isa<ConstantInt>(Cond)) break;
756  V = Cond->isNullValue() ? V2Element : V1Element;
757  }
758  Result.push_back(V);
759  }
760 
761  // If we were able to build the vector, return it.
762  if (Result.size() == V1->getType()->getVectorNumElements())
763  return ConstantVector::get(Result);
764  }
765 
766  if (isa<UndefValue>(Cond)) {
767  if (isa<UndefValue>(V1)) return V1;
768  return V2;
769  }
770  if (isa<UndefValue>(V1)) return V2;
771  if (isa<UndefValue>(V2)) return V1;
772  if (V1 == V2) return V1;
773 
774  if (ConstantExpr *TrueVal = dyn_cast<ConstantExpr>(V1)) {
775  if (TrueVal->getOpcode() == Instruction::Select)
776  if (TrueVal->getOperand(0) == Cond)
777  return ConstantExpr::getSelect(Cond, TrueVal->getOperand(1), V2);
778  }
779  if (ConstantExpr *FalseVal = dyn_cast<ConstantExpr>(V2)) {
780  if (FalseVal->getOpcode() == Instruction::Select)
781  if (FalseVal->getOperand(0) == Cond)
782  return ConstantExpr::getSelect(Cond, V1, FalseVal->getOperand(2));
783  }
784 
785  return nullptr;
786 }
787 
789  Constant *Idx) {
790  if (isa<UndefValue>(Val)) // ee(undef, x) -> undef
791  return UndefValue::get(Val->getType()->getVectorElementType());
792  if (Val->isNullValue()) // ee(zero, x) -> zero
794  // ee({w,x,y,z}, undef) -> undef
795  if (isa<UndefValue>(Idx))
796  return UndefValue::get(Val->getType()->getVectorElementType());
797 
798  if (ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx)) {
799  // ee({w,x,y,z}, wrong_value) -> undef
800  if (CIdx->uge(Val->getType()->getVectorNumElements()))
801  return UndefValue::get(Val->getType()->getVectorElementType());
802  return Val->getAggregateElement(CIdx->getZExtValue());
803  }
804  return nullptr;
805 }
806 
808  Constant *Elt,
809  Constant *Idx) {
810  if (isa<UndefValue>(Idx))
811  return UndefValue::get(Val->getType());
812 
813  ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx);
814  if (!CIdx) return nullptr;
815 
816  unsigned NumElts = Val->getType()->getVectorNumElements();
817  if (CIdx->uge(NumElts))
818  return UndefValue::get(Val->getType());
819 
821  Result.reserve(NumElts);
822  auto *Ty = Type::getInt32Ty(Val->getContext());
823  uint64_t IdxVal = CIdx->getZExtValue();
824  for (unsigned i = 0; i != NumElts; ++i) {
825  if (i == IdxVal) {
826  Result.push_back(Elt);
827  continue;
828  }
829 
831  Result.push_back(C);
832  }
833 
834  return ConstantVector::get(Result);
835 }
836 
838  Constant *V2,
839  Constant *Mask) {
840  unsigned MaskNumElts = Mask->getType()->getVectorNumElements();
841  Type *EltTy = V1->getType()->getVectorElementType();
842 
843  // Undefined shuffle mask -> undefined value.
844  if (isa<UndefValue>(Mask))
845  return UndefValue::get(VectorType::get(EltTy, MaskNumElts));
846 
847  // Don't break the bitcode reader hack.
848  if (isa<ConstantExpr>(Mask)) return nullptr;
849 
850  unsigned SrcNumElts = V1->getType()->getVectorNumElements();
851 
852  // Loop over the shuffle mask, evaluating each element.
854  for (unsigned i = 0; i != MaskNumElts; ++i) {
855  int Elt = ShuffleVectorInst::getMaskValue(Mask, i);
856  if (Elt == -1) {
857  Result.push_back(UndefValue::get(EltTy));
858  continue;
859  }
860  Constant *InElt;
861  if (unsigned(Elt) >= SrcNumElts*2)
862  InElt = UndefValue::get(EltTy);
863  else if (unsigned(Elt) >= SrcNumElts) {
864  Type *Ty = IntegerType::get(V2->getContext(), 32);
865  InElt =
867  ConstantInt::get(Ty, Elt - SrcNumElts));
868  } else {
869  Type *Ty = IntegerType::get(V1->getContext(), 32);
871  }
872  Result.push_back(InElt);
873  }
874 
875  return ConstantVector::get(Result);
876 }
877 
879  ArrayRef<unsigned> Idxs) {
880  // Base case: no indices, so return the entire value.
881  if (Idxs.empty())
882  return Agg;
883 
884  if (Constant *C = Agg->getAggregateElement(Idxs[0]))
886 
887  return nullptr;
888 }
889 
891  Constant *Val,
892  ArrayRef<unsigned> Idxs) {
893  // Base case: no indices, so replace the entire value.
894  if (Idxs.empty())
895  return Val;
896 
897  unsigned NumElts;
898  if (StructType *ST = dyn_cast<StructType>(Agg->getType()))
899  NumElts = ST->getNumElements();
900  else
901  NumElts = cast<SequentialType>(Agg->getType())->getNumElements();
902 
904  for (unsigned i = 0; i != NumElts; ++i) {
905  Constant *C = Agg->getAggregateElement(i);
906  if (!C) return nullptr;
907 
908  if (Idxs[0] == i)
909  C = ConstantFoldInsertValueInstruction(C, Val, Idxs.slice(1));
910 
911  Result.push_back(C);
912  }
913 
914  if (StructType *ST = dyn_cast<StructType>(Agg->getType()))
915  return ConstantStruct::get(ST, Result);
916  if (ArrayType *AT = dyn_cast<ArrayType>(Agg->getType()))
917  return ConstantArray::get(AT, Result);
918  return ConstantVector::get(Result);
919 }
920 
922  Constant *C2) {
923  assert(Instruction::isBinaryOp(Opcode) && "Non-binary instruction detected");
924 
925  // Handle scalar UndefValue. Vectors are always evaluated per element.
926  bool HasScalarUndef = !C1->getType()->isVectorTy() &&
927  (isa<UndefValue>(C1) || isa<UndefValue>(C2));
928  if (HasScalarUndef) {
929  switch (static_cast<Instruction::BinaryOps>(Opcode)) {
930  case Instruction::Xor:
931  if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
932  // Handle undef ^ undef -> 0 special case. This is a common
933  // idiom (misuse).
934  return Constant::getNullValue(C1->getType());
936  case Instruction::Add:
937  case Instruction::Sub:
938  return UndefValue::get(C1->getType());
939  case Instruction::And:
940  if (isa<UndefValue>(C1) && isa<UndefValue>(C2)) // undef & undef -> undef
941  return C1;
942  return Constant::getNullValue(C1->getType()); // undef & X -> 0
943  case Instruction::Mul: {
944  // undef * undef -> undef
945  if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
946  return C1;
947  const APInt *CV;
948  // X * undef -> undef if X is odd
949  if (match(C1, m_APInt(CV)) || match(C2, m_APInt(CV)))
950  if ((*CV)[0])
951  return UndefValue::get(C1->getType());
952 
953  // X * undef -> 0 otherwise
954  return Constant::getNullValue(C1->getType());
955  }
956  case Instruction::SDiv:
957  case Instruction::UDiv:
958  // X / undef -> undef
959  if (isa<UndefValue>(C2))
960  return C2;
961  // undef / 0 -> undef
962  // undef / 1 -> undef
963  if (match(C2, m_Zero()) || match(C2, m_One()))
964  return C1;
965  // undef / X -> 0 otherwise
966  return Constant::getNullValue(C1->getType());
967  case Instruction::URem:
968  case Instruction::SRem:
969  // X % undef -> undef
970  if (match(C2, m_Undef()))
971  return C2;
972  // undef % 0 -> undef
973  if (match(C2, m_Zero()))
974  return C1;
975  // undef % X -> 0 otherwise
976  return Constant::getNullValue(C1->getType());
977  case Instruction::Or: // X | undef -> -1
978  if (isa<UndefValue>(C1) && isa<UndefValue>(C2)) // undef | undef -> undef
979  return C1;
980  return Constant::getAllOnesValue(C1->getType()); // undef | X -> ~0
981  case Instruction::LShr:
982  // X >>l undef -> undef
983  if (isa<UndefValue>(C2))
984  return C2;
985  // undef >>l 0 -> undef
986  if (match(C2, m_Zero()))
987  return C1;
988  // undef >>l X -> 0
989  return Constant::getNullValue(C1->getType());
990  case Instruction::AShr:
991  // X >>a undef -> undef
992  if (isa<UndefValue>(C2))
993  return C2;
994  // undef >>a 0 -> undef
995  if (match(C2, m_Zero()))
996  return C1;
997  // TODO: undef >>a X -> undef if the shift is exact
998  // undef >>a X -> 0
999  return Constant::getNullValue(C1->getType());
1000  case Instruction::Shl:
1001  // X << undef -> undef
1002  if (isa<UndefValue>(C2))
1003  return C2;
1004  // undef << 0 -> undef
1005  if (match(C2, m_Zero()))
1006  return C1;
1007  // undef << X -> 0
1008  return Constant::getNullValue(C1->getType());
1009  case Instruction::FAdd:
1010  case Instruction::FSub:
1011  case Instruction::FMul:
1012  case Instruction::FDiv:
1013  case Instruction::FRem:
1014  // [any flop] undef, undef -> undef
1015  if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
1016  return C1;
1017  // [any flop] C, undef -> NaN
1018  // [any flop] undef, C -> NaN
1019  // We could potentially specialize NaN/Inf constants vs. 'normal'
1020  // constants (possibly differently depending on opcode and operand). This
1021  // would allow returning undef sometimes. But it is always safe to fold to
1022  // NaN because we can choose the undef operand as NaN, and any FP opcode
1023  // with a NaN operand will propagate NaN.
1024  return ConstantFP::getNaN(C1->getType());
1025  case Instruction::BinaryOpsEnd:
1026  llvm_unreachable("Invalid BinaryOp");
1027  }
1028  }
1029 
1030  // Neither constant should be UndefValue, unless these are vector constants.
1031  assert(!HasScalarUndef && "Unexpected UndefValue");
1032 
1033  // Handle simplifications when the RHS is a constant int.
1034  if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
1035  switch (Opcode) {
1036  case Instruction::Add:
1037  if (CI2->isZero()) return C1; // X + 0 == X
1038  break;
1039  case Instruction::Sub:
1040  if (CI2->isZero()) return C1; // X - 0 == X
1041  break;
1042  case Instruction::Mul:
1043  if (CI2->isZero()) return C2; // X * 0 == 0
1044  if (CI2->isOne())
1045  return C1; // X * 1 == X
1046  break;
1047  case Instruction::UDiv:
1048  case Instruction::SDiv:
1049  if (CI2->isOne())
1050  return C1; // X / 1 == X
1051  if (CI2->isZero())
1052  return UndefValue::get(CI2->getType()); // X / 0 == undef
1053  break;
1054  case Instruction::URem:
1055  case Instruction::SRem:
1056  if (CI2->isOne())
1057  return Constant::getNullValue(CI2->getType()); // X % 1 == 0
1058  if (CI2->isZero())
1059  return UndefValue::get(CI2->getType()); // X % 0 == undef
1060  break;
1061  case Instruction::And:
1062  if (CI2->isZero()) return C2; // X & 0 == 0
1063  if (CI2->isMinusOne())
1064  return C1; // X & -1 == X
1065 
1066  if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1067  // (zext i32 to i64) & 4294967295 -> (zext i32 to i64)
1068  if (CE1->getOpcode() == Instruction::ZExt) {
1069  unsigned DstWidth = CI2->getType()->getBitWidth();
1070  unsigned SrcWidth =
1071  CE1->getOperand(0)->getType()->getPrimitiveSizeInBits();
1072  APInt PossiblySetBits(APInt::getLowBitsSet(DstWidth, SrcWidth));
1073  if ((PossiblySetBits & CI2->getValue()) == PossiblySetBits)
1074  return C1;
1075  }
1076 
1077  // If and'ing the address of a global with a constant, fold it.
1078  if (CE1->getOpcode() == Instruction::PtrToInt &&
1079  isa<GlobalValue>(CE1->getOperand(0))) {
1080  GlobalValue *GV = cast<GlobalValue>(CE1->getOperand(0));
1081 
1082  unsigned GVAlign;
1083 
1084  if (Module *TheModule = GV->getParent()) {
1085  GVAlign = GV->getPointerAlignment(TheModule->getDataLayout());
1086 
1087  // If the function alignment is not specified then assume that it
1088  // is 4.
1089  // This is dangerous; on x86, the alignment of the pointer
1090  // corresponds to the alignment of the function, but might be less
1091  // than 4 if it isn't explicitly specified.
1092  // However, a fix for this behaviour was reverted because it
1093  // increased code size (see https://reviews.llvm.org/D55115)
1094  // FIXME: This code should be deleted once existing targets have
1095  // appropriate defaults
1096  if (GVAlign == 0U && isa<Function>(GV))
1097  GVAlign = 4U;
1098  } else if (isa<Function>(GV)) {
1099  // Without a datalayout we have to assume the worst case: that the
1100  // function pointer isn't aligned at all.
1101  GVAlign = 0U;
1102  } else {
1103  GVAlign = GV->getAlignment();
1104  }
1105 
1106  if (GVAlign > 1) {
1107  unsigned DstWidth = CI2->getType()->getBitWidth();
1108  unsigned SrcWidth = std::min(DstWidth, Log2_32(GVAlign));
1109  APInt BitsNotSet(APInt::getLowBitsSet(DstWidth, SrcWidth));
1110 
1111  // If checking bits we know are clear, return zero.
1112  if ((CI2->getValue() & BitsNotSet) == CI2->getValue())
1113  return Constant::getNullValue(CI2->getType());
1114  }
1115  }
1116  }
1117  break;
1118  case Instruction::Or:
1119  if (CI2->isZero()) return C1; // X | 0 == X
1120  if (CI2->isMinusOne())
1121  return C2; // X | -1 == -1
1122  break;
1123  case Instruction::Xor:
1124  if (CI2->isZero()) return C1; // X ^ 0 == X
1125 
1126  if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1127  switch (CE1->getOpcode()) {
1128  default: break;
1129  case Instruction::ICmp:
1130  case Instruction::FCmp:
1131  // cmp pred ^ true -> cmp !pred
1132  assert(CI2->isOne());
1133  CmpInst::Predicate pred = (CmpInst::Predicate)CE1->getPredicate();
1134  pred = CmpInst::getInversePredicate(pred);
1135  return ConstantExpr::getCompare(pred, CE1->getOperand(0),
1136  CE1->getOperand(1));
1137  }
1138  }
1139  break;
1140  case Instruction::AShr:
1141  // ashr (zext C to Ty), C2 -> lshr (zext C, CSA), C2
1142  if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1))
1143  if (CE1->getOpcode() == Instruction::ZExt) // Top bits known zero.
1144  return ConstantExpr::getLShr(C1, C2);
1145  break;
1146  }
1147  } else if (isa<ConstantInt>(C1)) {
1148  // If C1 is a ConstantInt and C2 is not, swap the operands.
1149  if (Instruction::isCommutative(Opcode))
1150  return ConstantExpr::get(Opcode, C2, C1);
1151  }
1152 
1153  if (ConstantInt *CI1 = dyn_cast<ConstantInt>(C1)) {
1154  if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
1155  const APInt &C1V = CI1->getValue();
1156  const APInt &C2V = CI2->getValue();
1157  switch (Opcode) {
1158  default:
1159  break;
1160  case Instruction::Add:
1161  return ConstantInt::get(CI1->getContext(), C1V + C2V);
1162  case Instruction::Sub:
1163  return ConstantInt::get(CI1->getContext(), C1V - C2V);
1164  case Instruction::Mul:
1165  return ConstantInt::get(CI1->getContext(), C1V * C2V);
1166  case Instruction::UDiv:
1167  assert(!CI2->isZero() && "Div by zero handled above");
1168  return ConstantInt::get(CI1->getContext(), C1V.udiv(C2V));
1169  case Instruction::SDiv:
1170  assert(!CI2->isZero() && "Div by zero handled above");
1171  if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
1172  return UndefValue::get(CI1->getType()); // MIN_INT / -1 -> undef
1173  return ConstantInt::get(CI1->getContext(), C1V.sdiv(C2V));
1174  case Instruction::URem:
1175  assert(!CI2->isZero() && "Div by zero handled above");
1176  return ConstantInt::get(CI1->getContext(), C1V.urem(C2V));
1177  case Instruction::SRem:
1178  assert(!CI2->isZero() && "Div by zero handled above");
1179  if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
1180  return UndefValue::get(CI1->getType()); // MIN_INT % -1 -> undef
1181  return ConstantInt::get(CI1->getContext(), C1V.srem(C2V));
1182  case Instruction::And:
1183  return ConstantInt::get(CI1->getContext(), C1V & C2V);
1184  case Instruction::Or:
1185  return ConstantInt::get(CI1->getContext(), C1V | C2V);
1186  case Instruction::Xor:
1187  return ConstantInt::get(CI1->getContext(), C1V ^ C2V);
1188  case Instruction::Shl:
1189  if (C2V.ult(C1V.getBitWidth()))
1190  return ConstantInt::get(CI1->getContext(), C1V.shl(C2V));
1191  return UndefValue::get(C1->getType()); // too big shift is undef
1192  case Instruction::LShr:
1193  if (C2V.ult(C1V.getBitWidth()))
1194  return ConstantInt::get(CI1->getContext(), C1V.lshr(C2V));
1195  return UndefValue::get(C1->getType()); // too big shift is undef
1196  case Instruction::AShr:
1197  if (C2V.ult(C1V.getBitWidth()))
1198  return ConstantInt::get(CI1->getContext(), C1V.ashr(C2V));
1199  return UndefValue::get(C1->getType()); // too big shift is undef
1200  }
1201  }
1202 
1203  switch (Opcode) {
1204  case Instruction::SDiv:
1205  case Instruction::UDiv:
1206  case Instruction::URem:
1207  case Instruction::SRem:
1208  case Instruction::LShr:
1209  case Instruction::AShr:
1210  case Instruction::Shl:
1211  if (CI1->isZero()) return C1;
1212  break;
1213  default:
1214  break;
1215  }
1216  } else if (ConstantFP *CFP1 = dyn_cast<ConstantFP>(C1)) {
1217  if (ConstantFP *CFP2 = dyn_cast<ConstantFP>(C2)) {
1218  const APFloat &C1V = CFP1->getValueAPF();
1219  const APFloat &C2V = CFP2->getValueAPF();
1220  APFloat C3V = C1V; // copy for modification
1221  switch (Opcode) {
1222  default:
1223  break;
1224  case Instruction::FAdd:
1225  (void)C3V.add(C2V, APFloat::rmNearestTiesToEven);
1226  return ConstantFP::get(C1->getContext(), C3V);
1227  case Instruction::FSub:
1228  (void)C3V.subtract(C2V, APFloat::rmNearestTiesToEven);
1229  return ConstantFP::get(C1->getContext(), C3V);
1230  case Instruction::FMul:
1231  (void)C3V.multiply(C2V, APFloat::rmNearestTiesToEven);
1232  return ConstantFP::get(C1->getContext(), C3V);
1233  case Instruction::FDiv:
1234  (void)C3V.divide(C2V, APFloat::rmNearestTiesToEven);
1235  return ConstantFP::get(C1->getContext(), C3V);
1236  case Instruction::FRem:
1237  (void)C3V.mod(C2V);
1238  return ConstantFP::get(C1->getContext(), C3V);
1239  }
1240  }
1241  } else if (VectorType *VTy = dyn_cast<VectorType>(C1->getType())) {
1242  // Fold each element and create a vector constant from those constants.
1244  Type *Ty = IntegerType::get(VTy->getContext(), 32);
1245  for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1246  Constant *ExtractIdx = ConstantInt::get(Ty, i);
1247  Constant *LHS = ConstantExpr::getExtractElement(C1, ExtractIdx);
1248  Constant *RHS = ConstantExpr::getExtractElement(C2, ExtractIdx);
1249 
1250  // If any element of a divisor vector is zero, the whole op is undef.
1251  if (Instruction::isIntDivRem(Opcode) && RHS->isNullValue())
1252  return UndefValue::get(VTy);
1253 
1254  Result.push_back(ConstantExpr::get(Opcode, LHS, RHS));
1255  }
1256 
1257  return ConstantVector::get(Result);
1258  }
1259 
1260  if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1261  // There are many possible foldings we could do here. We should probably
1262  // at least fold add of a pointer with an integer into the appropriate
1263  // getelementptr. This will improve alias analysis a bit.
1264 
1265  // Given ((a + b) + c), if (b + c) folds to something interesting, return
1266  // (a + (b + c)).
1267  if (Instruction::isAssociative(Opcode) && CE1->getOpcode() == Opcode) {
1268  Constant *T = ConstantExpr::get(Opcode, CE1->getOperand(1), C2);
1269  if (!isa<ConstantExpr>(T) || cast<ConstantExpr>(T)->getOpcode() != Opcode)
1270  return ConstantExpr::get(Opcode, CE1->getOperand(0), T);
1271  }
1272  } else if (isa<ConstantExpr>(C2)) {
1273  // If C2 is a constant expr and C1 isn't, flop them around and fold the
1274  // other way if possible.
1275  if (Instruction::isCommutative(Opcode))
1276  return ConstantFoldBinaryInstruction(Opcode, C2, C1);
1277  }
1278 
1279  // i1 can be simplified in many cases.
1280  if (C1->getType()->isIntegerTy(1)) {
1281  switch (Opcode) {
1282  case Instruction::Add:
1283  case Instruction::Sub:
1284  return ConstantExpr::getXor(C1, C2);
1285  case Instruction::Mul:
1286  return ConstantExpr::getAnd(C1, C2);
1287  case Instruction::Shl:
1288  case Instruction::LShr:
1289  case Instruction::AShr:
1290  // We can assume that C2 == 0. If it were one the result would be
1291  // undefined because the shift value is as large as the bitwidth.
1292  return C1;
1293  case Instruction::SDiv:
1294  case Instruction::UDiv:
1295  // We can assume that C2 == 1. If it were zero the result would be
1296  // undefined through division by zero.
1297  return C1;
1298  case Instruction::URem:
1299  case Instruction::SRem:
1300  // We can assume that C2 == 1. If it were zero the result would be
1301  // undefined through division by zero.
1302  return ConstantInt::getFalse(C1->getContext());
1303  default:
1304  break;
1305  }
1306  }
1307 
1308  // We don't know how to fold this.
1309  return nullptr;
1310 }
1311 
1312 /// This type is zero-sized if it's an array or structure of zero-sized types.
1313 /// The only leaf zero-sized type is an empty structure.
1314 static bool isMaybeZeroSizedType(Type *Ty) {
1315  if (StructType *STy = dyn_cast<StructType>(Ty)) {
1316  if (STy->isOpaque()) return true; // Can't say.
1317 
1318  // If all of elements have zero size, this does too.
1319  for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
1320  if (!isMaybeZeroSizedType(STy->getElementType(i))) return false;
1321  return true;
1322 
1323  } else if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
1324  return isMaybeZeroSizedType(ATy->getElementType());
1325  }
1326  return false;
1327 }
1328 
1329 /// Compare the two constants as though they were getelementptr indices.
1330 /// This allows coercion of the types to be the same thing.
1331 ///
1332 /// If the two constants are the "same" (after coercion), return 0. If the
1333 /// first is less than the second, return -1, if the second is less than the
1334 /// first, return 1. If the constants are not integral, return -2.
1335 ///
1336 static int IdxCompare(Constant *C1, Constant *C2, Type *ElTy) {
1337  if (C1 == C2) return 0;
1338 
1339  // Ok, we found a different index. If they are not ConstantInt, we can't do
1340  // anything with them.
1341  if (!isa<ConstantInt>(C1) || !isa<ConstantInt>(C2))
1342  return -2; // don't know!
1343 
1344  // We cannot compare the indices if they don't fit in an int64_t.
1345  if (cast<ConstantInt>(C1)->getValue().getActiveBits() > 64 ||
1346  cast<ConstantInt>(C2)->getValue().getActiveBits() > 64)
1347  return -2; // don't know!
1348 
1349  // Ok, we have two differing integer indices. Sign extend them to be the same
1350  // type.
1351  int64_t C1Val = cast<ConstantInt>(C1)->getSExtValue();
1352  int64_t C2Val = cast<ConstantInt>(C2)->getSExtValue();
1353 
1354  if (C1Val == C2Val) return 0; // They are equal
1355 
1356  // If the type being indexed over is really just a zero sized type, there is
1357  // no pointer difference being made here.
1358  if (isMaybeZeroSizedType(ElTy))
1359  return -2; // dunno.
1360 
1361  // If they are really different, now that they are the same type, then we
1362  // found a difference!
1363  if (C1Val < C2Val)
1364  return -1;
1365  else
1366  return 1;
1367 }
1368 
1369 /// This function determines if there is anything we can decide about the two
1370 /// constants provided. This doesn't need to handle simple things like
1371 /// ConstantFP comparisons, but should instead handle ConstantExprs.
1372 /// If we can determine that the two constants have a particular relation to
1373 /// each other, we should return the corresponding FCmpInst predicate,
1374 /// otherwise return FCmpInst::BAD_FCMP_PREDICATE. This is used below in
1375 /// ConstantFoldCompareInstruction.
1376 ///
1377 /// To simplify this code we canonicalize the relation so that the first
1378 /// operand is always the most "complex" of the two. We consider ConstantFP
1379 /// to be the simplest, and ConstantExprs to be the most complex.
1381  assert(V1->getType() == V2->getType() &&
1382  "Cannot compare values of different types!");
1383 
1384  // We do not know if a constant expression will evaluate to a number or NaN.
1385  // Therefore, we can only say that the relation is unordered or equal.
1386  if (V1 == V2) return FCmpInst::FCMP_UEQ;
1387 
1388  if (!isa<ConstantExpr>(V1)) {
1389  if (!isa<ConstantExpr>(V2)) {
1390  // Simple case, use the standard constant folder.
1391  ConstantInt *R = nullptr;
1392  R = dyn_cast<ConstantInt>(
1394  if (R && !R->isZero())
1395  return FCmpInst::FCMP_OEQ;
1396  R = dyn_cast<ConstantInt>(
1398  if (R && !R->isZero())
1399  return FCmpInst::FCMP_OLT;
1400  R = dyn_cast<ConstantInt>(
1402  if (R && !R->isZero())
1403  return FCmpInst::FCMP_OGT;
1404 
1405  // Nothing more we can do
1407  }
1408 
1409  // If the first operand is simple and second is ConstantExpr, swap operands.
1410  FCmpInst::Predicate SwappedRelation = evaluateFCmpRelation(V2, V1);
1411  if (SwappedRelation != FCmpInst::BAD_FCMP_PREDICATE)
1412  return FCmpInst::getSwappedPredicate(SwappedRelation);
1413  } else {
1414  // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1415  // constantexpr or a simple constant.
1416  ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1417  switch (CE1->getOpcode()) {
1418  case Instruction::FPTrunc:
1419  case Instruction::FPExt:
1420  case Instruction::UIToFP:
1421  case Instruction::SIToFP:
1422  // We might be able to do something with these but we don't right now.
1423  break;
1424  default:
1425  break;
1426  }
1427  }
1428  // There are MANY other foldings that we could perform here. They will
1429  // probably be added on demand, as they seem needed.
1431 }
1432 
1434  const GlobalValue *GV2) {
1435  auto isGlobalUnsafeForEquality = [](const GlobalValue *GV) {
1436  if (GV->hasExternalWeakLinkage() || GV->hasWeakAnyLinkage())
1437  return true;
1438  if (const auto *GVar = dyn_cast<GlobalVariable>(GV)) {
1439  Type *Ty = GVar->getValueType();
1440  // A global with opaque type might end up being zero sized.
1441  if (!Ty->isSized())
1442  return true;
1443  // A global with an empty type might lie at the address of any other
1444  // global.
1445  if (Ty->isEmptyTy())
1446  return true;
1447  }
1448  return false;
1449  };
1450  // Don't try to decide equality of aliases.
1451  if (!isa<GlobalAlias>(GV1) && !isa<GlobalAlias>(GV2))
1452  if (!isGlobalUnsafeForEquality(GV1) && !isGlobalUnsafeForEquality(GV2))
1453  return ICmpInst::ICMP_NE;
1455 }
1456 
1457 /// This function determines if there is anything we can decide about the two
1458 /// constants provided. This doesn't need to handle simple things like integer
1459 /// comparisons, but should instead handle ConstantExprs and GlobalValues.
1460 /// If we can determine that the two constants have a particular relation to
1461 /// each other, we should return the corresponding ICmp predicate, otherwise
1462 /// return ICmpInst::BAD_ICMP_PREDICATE.
1463 ///
1464 /// To simplify this code we canonicalize the relation so that the first
1465 /// operand is always the most "complex" of the two. We consider simple
1466 /// constants (like ConstantInt) to be the simplest, followed by
1467 /// GlobalValues, followed by ConstantExpr's (the most complex).
1468 ///
1470  bool isSigned) {
1471  assert(V1->getType() == V2->getType() &&
1472  "Cannot compare different types of values!");
1473  if (V1 == V2) return ICmpInst::ICMP_EQ;
1474 
1475  if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1) &&
1476  !isa<BlockAddress>(V1)) {
1477  if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2) &&
1478  !isa<BlockAddress>(V2)) {
1479  // We distilled this down to a simple case, use the standard constant
1480  // folder.
1481  ConstantInt *R = nullptr;
1483  R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1484  if (R && !R->isZero())
1485  return pred;
1486  pred = isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1487  R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1488  if (R && !R->isZero())
1489  return pred;
1490  pred = isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1491  R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1492  if (R && !R->isZero())
1493  return pred;
1494 
1495  // If we couldn't figure it out, bail.
1497  }
1498 
1499  // If the first operand is simple, swap operands.
1500  ICmpInst::Predicate SwappedRelation =
1501  evaluateICmpRelation(V2, V1, isSigned);
1502  if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1503  return ICmpInst::getSwappedPredicate(SwappedRelation);
1504 
1505  } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1)) {
1506  if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1507  ICmpInst::Predicate SwappedRelation =
1508  evaluateICmpRelation(V2, V1, isSigned);
1509  if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1510  return ICmpInst::getSwappedPredicate(SwappedRelation);
1512  }
1513 
1514  // Now we know that the RHS is a GlobalValue, BlockAddress or simple
1515  // constant (which, since the types must match, means that it's a
1516  // ConstantPointerNull).
1517  if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
1518  return areGlobalsPotentiallyEqual(GV, GV2);
1519  } else if (isa<BlockAddress>(V2)) {
1520  return ICmpInst::ICMP_NE; // Globals never equal labels.
1521  } else {
1522  assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!");
1523  // GlobalVals can never be null unless they have external weak linkage.
1524  // We don't try to evaluate aliases here.
1525  // NOTE: We should not be doing this constant folding if null pointer
1526  // is considered valid for the function. But currently there is no way to
1527  // query it from the Constant type.
1528  if (!GV->hasExternalWeakLinkage() && !isa<GlobalAlias>(GV) &&
1529  !NullPointerIsDefined(nullptr /* F */,
1530  GV->getType()->getAddressSpace()))
1531  return ICmpInst::ICMP_NE;
1532  }
1533  } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(V1)) {
1534  if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1535  ICmpInst::Predicate SwappedRelation =
1536  evaluateICmpRelation(V2, V1, isSigned);
1537  if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1538  return ICmpInst::getSwappedPredicate(SwappedRelation);
1540  }
1541 
1542  // Now we know that the RHS is a GlobalValue, BlockAddress or simple
1543  // constant (which, since the types must match, means that it is a
1544  // ConstantPointerNull).
1545  if (const BlockAddress *BA2 = dyn_cast<BlockAddress>(V2)) {
1546  // Block address in another function can't equal this one, but block
1547  // addresses in the current function might be the same if blocks are
1548  // empty.
1549  if (BA2->getFunction() != BA->getFunction())
1550  return ICmpInst::ICMP_NE;
1551  } else {
1552  // Block addresses aren't null, don't equal the address of globals.
1553  assert((isa<ConstantPointerNull>(V2) || isa<GlobalValue>(V2)) &&
1554  "Canonicalization guarantee!");
1555  return ICmpInst::ICMP_NE;
1556  }
1557  } else {
1558  // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1559  // constantexpr, a global, block address, or a simple constant.
1560  ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1561  Constant *CE1Op0 = CE1->getOperand(0);
1562 
1563  switch (CE1->getOpcode()) {
1564  case Instruction::Trunc:
1565  case Instruction::FPTrunc:
1566  case Instruction::FPExt:
1567  case Instruction::FPToUI:
1568  case Instruction::FPToSI:
1569  break; // We can't evaluate floating point casts or truncations.
1570 
1571  case Instruction::UIToFP:
1572  case Instruction::SIToFP:
1573  case Instruction::BitCast:
1574  case Instruction::ZExt:
1575  case Instruction::SExt:
1576  // We can't evaluate floating point casts or truncations.
1577  if (CE1Op0->getType()->isFPOrFPVectorTy())
1578  break;
1579 
1580  // If the cast is not actually changing bits, and the second operand is a
1581  // null pointer, do the comparison with the pre-casted value.
1582  if (V2->isNullValue() && CE1->getType()->isIntOrPtrTy()) {
1583  if (CE1->getOpcode() == Instruction::ZExt) isSigned = false;
1584  if (CE1->getOpcode() == Instruction::SExt) isSigned = true;
1585  return evaluateICmpRelation(CE1Op0,
1586  Constant::getNullValue(CE1Op0->getType()),
1587  isSigned);
1588  }
1589  break;
1590 
1591  case Instruction::GetElementPtr: {
1592  GEPOperator *CE1GEP = cast<GEPOperator>(CE1);
1593  // Ok, since this is a getelementptr, we know that the constant has a
1594  // pointer type. Check the various cases.
1595  if (isa<ConstantPointerNull>(V2)) {
1596  // If we are comparing a GEP to a null pointer, check to see if the base
1597  // of the GEP equals the null pointer.
1598  if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1599  if (GV->hasExternalWeakLinkage())
1600  // Weak linkage GVals could be zero or not. We're comparing that
1601  // to null pointer so its greater-or-equal
1602  return isSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE;
1603  else
1604  // If its not weak linkage, the GVal must have a non-zero address
1605  // so the result is greater-than
1606  return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1607  } else if (isa<ConstantPointerNull>(CE1Op0)) {
1608  // If we are indexing from a null pointer, check to see if we have any
1609  // non-zero indices.
1610  for (unsigned i = 1, e = CE1->getNumOperands(); i != e; ++i)
1611  if (!CE1->getOperand(i)->isNullValue())
1612  // Offsetting from null, must not be equal.
1613  return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1614  // Only zero indexes from null, must still be zero.
1615  return ICmpInst::ICMP_EQ;
1616  }
1617  // Otherwise, we can't really say if the first operand is null or not.
1618  } else if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
1619  if (isa<ConstantPointerNull>(CE1Op0)) {
1620  if (GV2->hasExternalWeakLinkage())
1621  // Weak linkage GVals could be zero or not. We're comparing it to
1622  // a null pointer, so its less-or-equal
1623  return isSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE;
1624  else
1625  // If its not weak linkage, the GVal must have a non-zero address
1626  // so the result is less-than
1627  return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1628  } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1629  if (GV == GV2) {
1630  // If this is a getelementptr of the same global, then it must be
1631  // different. Because the types must match, the getelementptr could
1632  // only have at most one index, and because we fold getelementptr's
1633  // with a single zero index, it must be nonzero.
1634  assert(CE1->getNumOperands() == 2 &&
1635  !CE1->getOperand(1)->isNullValue() &&
1636  "Surprising getelementptr!");
1637  return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1638  } else {
1639  if (CE1GEP->hasAllZeroIndices())
1640  return areGlobalsPotentiallyEqual(GV, GV2);
1642  }
1643  }
1644  } else {
1645  ConstantExpr *CE2 = cast<ConstantExpr>(V2);
1646  Constant *CE2Op0 = CE2->getOperand(0);
1647 
1648  // There are MANY other foldings that we could perform here. They will
1649  // probably be added on demand, as they seem needed.
1650  switch (CE2->getOpcode()) {
1651  default: break;
1652  case Instruction::GetElementPtr:
1653  // By far the most common case to handle is when the base pointers are
1654  // obviously to the same global.
1655  if (isa<GlobalValue>(CE1Op0) && isa<GlobalValue>(CE2Op0)) {
1656  // Don't know relative ordering, but check for inequality.
1657  if (CE1Op0 != CE2Op0) {
1658  GEPOperator *CE2GEP = cast<GEPOperator>(CE2);
1659  if (CE1GEP->hasAllZeroIndices() && CE2GEP->hasAllZeroIndices())
1660  return areGlobalsPotentiallyEqual(cast<GlobalValue>(CE1Op0),
1661  cast<GlobalValue>(CE2Op0));
1663  }
1664  // Ok, we know that both getelementptr instructions are based on the
1665  // same global. From this, we can precisely determine the relative
1666  // ordering of the resultant pointers.
1667  unsigned i = 1;
1668 
1669  // The logic below assumes that the result of the comparison
1670  // can be determined by finding the first index that differs.
1671  // This doesn't work if there is over-indexing in any
1672  // subsequent indices, so check for that case first.
1673  if (!CE1->isGEPWithNoNotionalOverIndexing() ||
1675  return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1676 
1677  // Compare all of the operands the GEP's have in common.
1678  gep_type_iterator GTI = gep_type_begin(CE1);
1679  for (;i != CE1->getNumOperands() && i != CE2->getNumOperands();
1680  ++i, ++GTI)
1681  switch (IdxCompare(CE1->getOperand(i),
1682  CE2->getOperand(i), GTI.getIndexedType())) {
1683  case -1: return isSigned ? ICmpInst::ICMP_SLT:ICmpInst::ICMP_ULT;
1684  case 1: return isSigned ? ICmpInst::ICMP_SGT:ICmpInst::ICMP_UGT;
1685  case -2: return ICmpInst::BAD_ICMP_PREDICATE;
1686  }
1687 
1688  // Ok, we ran out of things they have in common. If any leftovers
1689  // are non-zero then we have a difference, otherwise we are equal.
1690  for (; i < CE1->getNumOperands(); ++i)
1691  if (!CE1->getOperand(i)->isNullValue()) {
1692  if (isa<ConstantInt>(CE1->getOperand(i)))
1693  return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1694  else
1695  return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1696  }
1697 
1698  for (; i < CE2->getNumOperands(); ++i)
1699  if (!CE2->getOperand(i)->isNullValue()) {
1700  if (isa<ConstantInt>(CE2->getOperand(i)))
1701  return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1702  else
1703  return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1704  }
1705  return ICmpInst::ICMP_EQ;
1706  }
1707  }
1708  }
1709  break;
1710  }
1711  default:
1712  break;
1713  }
1714  }
1715 
1717 }
1718 
1720  Constant *C1, Constant *C2) {
1721  Type *ResultTy;
1722  if (VectorType *VT = dyn_cast<VectorType>(C1->getType()))
1723  ResultTy = VectorType::get(Type::getInt1Ty(C1->getContext()),
1724  VT->getNumElements());
1725  else
1726  ResultTy = Type::getInt1Ty(C1->getContext());
1727 
1728  // Fold FCMP_FALSE/FCMP_TRUE unconditionally.
1729  if (pred == FCmpInst::FCMP_FALSE)
1730  return Constant::getNullValue(ResultTy);
1731 
1732  if (pred == FCmpInst::FCMP_TRUE)
1733  return Constant::getAllOnesValue(ResultTy);
1734 
1735  // Handle some degenerate cases first
1736  if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
1738  bool isIntegerPredicate = ICmpInst::isIntPredicate(Predicate);
1739  // For EQ and NE, we can always pick a value for the undef to make the
1740  // predicate pass or fail, so we can return undef.
1741  // Also, if both operands are undef, we can return undef for int comparison.
1742  if (ICmpInst::isEquality(Predicate) || (isIntegerPredicate && C1 == C2))
1743  return UndefValue::get(ResultTy);
1744 
1745  // Otherwise, for integer compare, pick the same value as the non-undef
1746  // operand, and fold it to true or false.
1747  if (isIntegerPredicate)
1748  return ConstantInt::get(ResultTy, CmpInst::isTrueWhenEqual(Predicate));
1749 
1750  // Choosing NaN for the undef will always make unordered comparison succeed
1751  // and ordered comparison fails.
1752  return ConstantInt::get(ResultTy, CmpInst::isUnordered(Predicate));
1753  }
1754 
1755  // icmp eq/ne(null,GV) -> false/true
1756  if (C1->isNullValue()) {
1757  if (const GlobalValue *GV = dyn_cast<GlobalValue>(C2))
1758  // Don't try to evaluate aliases. External weak GV can be null.
1759  if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage() &&
1760  !NullPointerIsDefined(nullptr /* F */,
1761  GV->getType()->getAddressSpace())) {
1762  if (pred == ICmpInst::ICMP_EQ)
1763  return ConstantInt::getFalse(C1->getContext());
1764  else if (pred == ICmpInst::ICMP_NE)
1765  return ConstantInt::getTrue(C1->getContext());
1766  }
1767  // icmp eq/ne(GV,null) -> false/true
1768  } else if (C2->isNullValue()) {
1769  if (const GlobalValue *GV = dyn_cast<GlobalValue>(C1))
1770  // Don't try to evaluate aliases. External weak GV can be null.
1771  if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage() &&
1772  !NullPointerIsDefined(nullptr /* F */,
1773  GV->getType()->getAddressSpace())) {
1774  if (pred == ICmpInst::ICMP_EQ)
1775  return ConstantInt::getFalse(C1->getContext());
1776  else if (pred == ICmpInst::ICMP_NE)
1777  return ConstantInt::getTrue(C1->getContext());
1778  }
1779  }
1780 
1781  // If the comparison is a comparison between two i1's, simplify it.
1782  if (C1->getType()->isIntegerTy(1)) {
1783  switch(pred) {
1784  case ICmpInst::ICMP_EQ:
1785  if (isa<ConstantInt>(C2))
1788  case ICmpInst::ICMP_NE:
1789  return ConstantExpr::getXor(C1, C2);
1790  default:
1791  break;
1792  }
1793  }
1794 
1795  if (isa<ConstantInt>(C1) && isa<ConstantInt>(C2)) {
1796  const APInt &V1 = cast<ConstantInt>(C1)->getValue();
1797  const APInt &V2 = cast<ConstantInt>(C2)->getValue();
1798  switch (pred) {
1799  default: llvm_unreachable("Invalid ICmp Predicate");
1800  case ICmpInst::ICMP_EQ: return ConstantInt::get(ResultTy, V1 == V2);
1801  case ICmpInst::ICMP_NE: return ConstantInt::get(ResultTy, V1 != V2);
1802  case ICmpInst::ICMP_SLT: return ConstantInt::get(ResultTy, V1.slt(V2));
1803  case ICmpInst::ICMP_SGT: return ConstantInt::get(ResultTy, V1.sgt(V2));
1804  case ICmpInst::ICMP_SLE: return ConstantInt::get(ResultTy, V1.sle(V2));
1805  case ICmpInst::ICMP_SGE: return ConstantInt::get(ResultTy, V1.sge(V2));
1806  case ICmpInst::ICMP_ULT: return ConstantInt::get(ResultTy, V1.ult(V2));
1807  case ICmpInst::ICMP_UGT: return ConstantInt::get(ResultTy, V1.ugt(V2));
1808  case ICmpInst::ICMP_ULE: return ConstantInt::get(ResultTy, V1.ule(V2));
1809  case ICmpInst::ICMP_UGE: return ConstantInt::get(ResultTy, V1.uge(V2));
1810  }
1811  } else if (isa<ConstantFP>(C1) && isa<ConstantFP>(C2)) {
1812  const APFloat &C1V = cast<ConstantFP>(C1)->getValueAPF();
1813  const APFloat &C2V = cast<ConstantFP>(C2)->getValueAPF();
1814  APFloat::cmpResult R = C1V.compare(C2V);
1815  switch (pred) {
1816  default: llvm_unreachable("Invalid FCmp Predicate");
1817  case FCmpInst::FCMP_FALSE: return Constant::getNullValue(ResultTy);
1818  case FCmpInst::FCMP_TRUE: return Constant::getAllOnesValue(ResultTy);
1819  case FCmpInst::FCMP_UNO:
1820  return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered);
1821  case FCmpInst::FCMP_ORD:
1822  return ConstantInt::get(ResultTy, R!=APFloat::cmpUnordered);
1823  case FCmpInst::FCMP_UEQ:
1824  return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1825  R==APFloat::cmpEqual);
1826  case FCmpInst::FCMP_OEQ:
1827  return ConstantInt::get(ResultTy, R==APFloat::cmpEqual);
1828  case FCmpInst::FCMP_UNE:
1829  return ConstantInt::get(ResultTy, R!=APFloat::cmpEqual);
1830  case FCmpInst::FCMP_ONE:
1831  return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
1833  case FCmpInst::FCMP_ULT:
1834  return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1836  case FCmpInst::FCMP_OLT:
1837  return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan);
1838  case FCmpInst::FCMP_UGT:
1839  return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1841  case FCmpInst::FCMP_OGT:
1842  return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan);
1843  case FCmpInst::FCMP_ULE:
1844  return ConstantInt::get(ResultTy, R!=APFloat::cmpGreaterThan);
1845  case FCmpInst::FCMP_OLE:
1846  return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
1847  R==APFloat::cmpEqual);
1848  case FCmpInst::FCMP_UGE:
1849  return ConstantInt::get(ResultTy, R!=APFloat::cmpLessThan);
1850  case FCmpInst::FCMP_OGE:
1851  return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan ||
1852  R==APFloat::cmpEqual);
1853  }
1854  } else if (C1->getType()->isVectorTy()) {
1855  // If we can constant fold the comparison of each element, constant fold
1856  // the whole vector comparison.
1857  SmallVector<Constant*, 4> ResElts;
1858  Type *Ty = IntegerType::get(C1->getContext(), 32);
1859  // Compare the elements, producing an i1 result or constant expr.
1860  for (unsigned i = 0, e = C1->getType()->getVectorNumElements(); i != e;++i){
1861  Constant *C1E =
1863  Constant *C2E =
1865 
1866  ResElts.push_back(ConstantExpr::getCompare(pred, C1E, C2E));
1867  }
1868 
1869  return ConstantVector::get(ResElts);
1870  }
1871 
1872  if (C1->getType()->isFloatingPointTy() &&
1873  // Only call evaluateFCmpRelation if we have a constant expr to avoid
1874  // infinite recursive loop
1875  (isa<ConstantExpr>(C1) || isa<ConstantExpr>(C2))) {
1876  int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
1877  switch (evaluateFCmpRelation(C1, C2)) {
1878  default: llvm_unreachable("Unknown relation!");
1879  case FCmpInst::FCMP_UNO:
1880  case FCmpInst::FCMP_ORD:
1881  case FCmpInst::FCMP_UNE:
1882  case FCmpInst::FCMP_ULT:
1883  case FCmpInst::FCMP_UGT:
1884  case FCmpInst::FCMP_ULE:
1885  case FCmpInst::FCMP_UGE:
1886  case FCmpInst::FCMP_TRUE:
1887  case FCmpInst::FCMP_FALSE:
1889  break; // Couldn't determine anything about these constants.
1890  case FCmpInst::FCMP_OEQ: // We know that C1 == C2
1891  Result = (pred == FCmpInst::FCMP_UEQ || pred == FCmpInst::FCMP_OEQ ||
1892  pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE ||
1893  pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
1894  break;
1895  case FCmpInst::FCMP_OLT: // We know that C1 < C2
1896  Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
1897  pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT ||
1898  pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE);
1899  break;
1900  case FCmpInst::FCMP_OGT: // We know that C1 > C2
1901  Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
1902  pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT ||
1903  pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
1904  break;
1905  case FCmpInst::FCMP_OLE: // We know that C1 <= C2
1906  // We can only partially decide this relation.
1907  if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
1908  Result = 0;
1909  else if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
1910  Result = 1;
1911  break;
1912  case FCmpInst::FCMP_OGE: // We known that C1 >= C2
1913  // We can only partially decide this relation.
1914  if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
1915  Result = 0;
1916  else if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
1917  Result = 1;
1918  break;
1919  case FCmpInst::FCMP_ONE: // We know that C1 != C2
1920  // We can only partially decide this relation.
1921  if (pred == FCmpInst::FCMP_OEQ || pred == FCmpInst::FCMP_UEQ)
1922  Result = 0;
1923  else if (pred == FCmpInst::FCMP_ONE || pred == FCmpInst::FCMP_UNE)
1924  Result = 1;
1925  break;
1926  case FCmpInst::FCMP_UEQ: // We know that C1 == C2 || isUnordered(C1, C2).
1927  // We can only partially decide this relation.
1928  if (pred == FCmpInst::FCMP_ONE)
1929  Result = 0;
1930  else if (pred == FCmpInst::FCMP_UEQ)
1931  Result = 1;
1932  break;
1933  }
1934 
1935  // If we evaluated the result, return it now.
1936  if (Result != -1)
1937  return ConstantInt::get(ResultTy, Result);
1938 
1939  } else {
1940  // Evaluate the relation between the two constants, per the predicate.
1941  int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
1942  switch (evaluateICmpRelation(C1, C2,
1944  default: llvm_unreachable("Unknown relational!");
1946  break; // Couldn't determine anything about these constants.
1947  case ICmpInst::ICMP_EQ: // We know the constants are equal!
1948  // If we know the constants are equal, we can decide the result of this
1949  // computation precisely.
1951  break;
1952  case ICmpInst::ICMP_ULT:
1953  switch (pred) {
1955  Result = 1; break;
1957  Result = 0; break;
1958  }
1959  break;
1960  case ICmpInst::ICMP_SLT:
1961  switch (pred) {
1963  Result = 1; break;
1965  Result = 0; break;
1966  }
1967  break;
1968  case ICmpInst::ICMP_UGT:
1969  switch (pred) {
1971  Result = 1; break;
1973  Result = 0; break;
1974  }
1975  break;
1976  case ICmpInst::ICMP_SGT:
1977  switch (pred) {
1979  Result = 1; break;
1981  Result = 0; break;
1982  }
1983  break;
1984  case ICmpInst::ICMP_ULE:
1985  if (pred == ICmpInst::ICMP_UGT) Result = 0;
1986  if (pred == ICmpInst::ICMP_ULT || pred == ICmpInst::ICMP_ULE) Result = 1;
1987  break;
1988  case ICmpInst::ICMP_SLE:
1989  if (pred == ICmpInst::ICMP_SGT) Result = 0;
1990  if (pred == ICmpInst::ICMP_SLT || pred == ICmpInst::ICMP_SLE) Result = 1;
1991  break;
1992  case ICmpInst::ICMP_UGE:
1993  if (pred == ICmpInst::ICMP_ULT) Result = 0;
1994  if (pred == ICmpInst::ICMP_UGT || pred == ICmpInst::ICMP_UGE) Result = 1;
1995  break;
1996  case ICmpInst::ICMP_SGE:
1997  if (pred == ICmpInst::ICMP_SLT) Result = 0;
1998  if (pred == ICmpInst::ICMP_SGT || pred == ICmpInst::ICMP_SGE) Result = 1;
1999  break;
2000  case ICmpInst::ICMP_NE:
2001  if (pred == ICmpInst::ICMP_EQ) Result = 0;
2002  if (pred == ICmpInst::ICMP_NE) Result = 1;
2003  break;
2004  }
2005 
2006  // If we evaluated the result, return it now.
2007  if (Result != -1)
2008  return ConstantInt::get(ResultTy, Result);
2009 
2010  // If the right hand side is a bitcast, try using its inverse to simplify
2011  // it by moving it to the left hand side. We can't do this if it would turn
2012  // a vector compare into a scalar compare or visa versa, or if it would turn
2013  // the operands into FP values.
2014  if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(C2)) {
2015  Constant *CE2Op0 = CE2->getOperand(0);
2016  if (CE2->getOpcode() == Instruction::BitCast &&
2017  CE2->getType()->isVectorTy() == CE2Op0->getType()->isVectorTy() &&
2018  !CE2Op0->getType()->isFPOrFPVectorTy()) {
2020  return ConstantExpr::getICmp(pred, Inverse, CE2Op0);
2021  }
2022  }
2023 
2024  // If the left hand side is an extension, try eliminating it.
2025  if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
2026  if ((CE1->getOpcode() == Instruction::SExt &&
2028  (CE1->getOpcode() == Instruction::ZExt &&
2030  Constant *CE1Op0 = CE1->getOperand(0);
2031  Constant *CE1Inverse = ConstantExpr::getTrunc(CE1, CE1Op0->getType());
2032  if (CE1Inverse == CE1Op0) {
2033  // Check whether we can safely truncate the right hand side.
2034  Constant *C2Inverse = ConstantExpr::getTrunc(C2, CE1Op0->getType());
2035  if (ConstantExpr::getCast(CE1->getOpcode(), C2Inverse,
2036  C2->getType()) == C2)
2037  return ConstantExpr::getICmp(pred, CE1Inverse, C2Inverse);
2038  }
2039  }
2040  }
2041 
2042  if ((!isa<ConstantExpr>(C1) && isa<ConstantExpr>(C2)) ||
2043  (C1->isNullValue() && !C2->isNullValue())) {
2044  // If C2 is a constant expr and C1 isn't, flip them around and fold the
2045  // other way if possible.
2046  // Also, if C1 is null and C2 isn't, flip them around.
2048  return ConstantExpr::getICmp(pred, C2, C1);
2049  }
2050  }
2051  return nullptr;
2052 }
2053 
2054 /// Test whether the given sequence of *normalized* indices is "inbounds".
2055 template<typename IndexTy>
2057  // No indices means nothing that could be out of bounds.
2058  if (Idxs.empty()) return true;
2059 
2060  // If the first index is zero, it's in bounds.
2061  if (cast<Constant>(Idxs[0])->isNullValue()) return true;
2062 
2063  // If the first index is one and all the rest are zero, it's in bounds,
2064  // by the one-past-the-end rule.
2065  if (auto *CI = dyn_cast<ConstantInt>(Idxs[0])) {
2066  if (!CI->isOne())
2067  return false;
2068  } else {
2069  auto *CV = cast<ConstantDataVector>(Idxs[0]);
2070  CI = dyn_cast_or_null<ConstantInt>(CV->getSplatValue());
2071  if (!CI || !CI->isOne())
2072  return false;
2073  }
2074 
2075  for (unsigned i = 1, e = Idxs.size(); i != e; ++i)
2076  if (!cast<Constant>(Idxs[i])->isNullValue())
2077  return false;
2078  return true;
2079 }
2080 
2081 /// Test whether a given ConstantInt is in-range for a SequentialType.
2082 static bool isIndexInRangeOfArrayType(uint64_t NumElements,
2083  const ConstantInt *CI) {
2084  // We cannot bounds check the index if it doesn't fit in an int64_t.
2085  if (CI->getValue().getMinSignedBits() > 64)
2086  return false;
2087 
2088  // A negative index or an index past the end of our sequential type is
2089  // considered out-of-range.
2090  int64_t IndexVal = CI->getSExtValue();
2091  if (IndexVal < 0 || (NumElements > 0 && (uint64_t)IndexVal >= NumElements))
2092  return false;
2093 
2094  // Otherwise, it is in-range.
2095  return true;
2096 }
2097 
2099  bool InBounds,
2100  Optional<unsigned> InRangeIndex,
2101  ArrayRef<Value *> Idxs) {
2102  if (Idxs.empty()) return C;
2103 
2105  PointeeTy, C, makeArrayRef((Value *const *)Idxs.data(), Idxs.size()));
2106 
2107  if (isa<UndefValue>(C))
2108  return UndefValue::get(GEPTy);
2109 
2110  Constant *Idx0 = cast<Constant>(Idxs[0]);
2111  if (Idxs.size() == 1 && (Idx0->isNullValue() || isa<UndefValue>(Idx0)))
2112  return GEPTy->isVectorTy() && !C->getType()->isVectorTy()
2114  cast<VectorType>(GEPTy)->getNumElements(), C)
2115  : C;
2116 
2117  if (C->isNullValue()) {
2118  bool isNull = true;
2119  for (unsigned i = 0, e = Idxs.size(); i != e; ++i)
2120  if (!isa<UndefValue>(Idxs[i]) &&
2121  !cast<Constant>(Idxs[i])->isNullValue()) {
2122  isNull = false;
2123  break;
2124  }
2125  if (isNull) {
2126  PointerType *PtrTy = cast<PointerType>(C->getType()->getScalarType());
2127  Type *Ty = GetElementPtrInst::getIndexedType(PointeeTy, Idxs);
2128 
2129  assert(Ty && "Invalid indices for GEP!");
2130  Type *OrigGEPTy = PointerType::get(Ty, PtrTy->getAddressSpace());
2131  Type *GEPTy = PointerType::get(Ty, PtrTy->getAddressSpace());
2132  if (VectorType *VT = dyn_cast<VectorType>(C->getType()))
2133  GEPTy = VectorType::get(OrigGEPTy, VT->getNumElements());
2134 
2135  // The GEP returns a vector of pointers when one of more of
2136  // its arguments is a vector.
2137  for (unsigned i = 0, e = Idxs.size(); i != e; ++i) {
2138  if (auto *VT = dyn_cast<VectorType>(Idxs[i]->getType())) {
2139  GEPTy = VectorType::get(OrigGEPTy, VT->getNumElements());
2140  break;
2141  }
2142  }
2143 
2144  return Constant::getNullValue(GEPTy);
2145  }
2146  }
2147 
2148  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2149  // Combine Indices - If the source pointer to this getelementptr instruction
2150  // is a getelementptr instruction, combine the indices of the two
2151  // getelementptr instructions into a single instruction.
2152  //
2153  if (CE->getOpcode() == Instruction::GetElementPtr) {
2154  gep_type_iterator LastI = gep_type_end(CE);
2155  for (gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
2156  I != E; ++I)
2157  LastI = I;
2158 
2159  // We cannot combine indices if doing so would take us outside of an
2160  // array or vector. Doing otherwise could trick us if we evaluated such a
2161  // GEP as part of a load.
2162  //
2163  // e.g. Consider if the original GEP was:
2164  // i8* getelementptr ({ [2 x i8], i32, i8, [3 x i8] }* @main.c,
2165  // i32 0, i32 0, i64 0)
2166  //
2167  // If we then tried to offset it by '8' to get to the third element,
2168  // an i8, we should *not* get:
2169  // i8* getelementptr ({ [2 x i8], i32, i8, [3 x i8] }* @main.c,
2170  // i32 0, i32 0, i64 8)
2171  //
2172  // This GEP tries to index array element '8 which runs out-of-bounds.
2173  // Subsequent evaluation would get confused and produce erroneous results.
2174  //
2175  // The following prohibits such a GEP from being formed by checking to see
2176  // if the index is in-range with respect to an array.
2177  // TODO: This code may be extended to handle vectors as well.
2178  bool PerformFold = false;
2179  if (Idx0->isNullValue())
2180  PerformFold = true;
2181  else if (LastI.isSequential())
2182  if (ConstantInt *CI = dyn_cast<ConstantInt>(Idx0))
2183  PerformFold = (!LastI.isBoundedSequential() ||
2185  LastI.getSequentialNumElements(), CI)) &&
2186  !CE->getOperand(CE->getNumOperands() - 1)
2187  ->getType()
2188  ->isVectorTy();
2189 
2190  if (PerformFold) {
2191  SmallVector<Value*, 16> NewIndices;
2192  NewIndices.reserve(Idxs.size() + CE->getNumOperands());
2193  NewIndices.append(CE->op_begin() + 1, CE->op_end() - 1);
2194 
2195  // Add the last index of the source with the first index of the new GEP.
2196  // Make sure to handle the case when they are actually different types.
2197  Constant *Combined = CE->getOperand(CE->getNumOperands()-1);
2198  // Otherwise it must be an array.
2199  if (!Idx0->isNullValue()) {
2200  Type *IdxTy = Combined->getType();
2201  if (IdxTy != Idx0->getType()) {
2202  unsigned CommonExtendedWidth =
2203  std::max(IdxTy->getIntegerBitWidth(),
2204  Idx0->getType()->getIntegerBitWidth());
2205  CommonExtendedWidth = std::max(CommonExtendedWidth, 64U);
2206 
2207  Type *CommonTy =
2208  Type::getIntNTy(IdxTy->getContext(), CommonExtendedWidth);
2209  Constant *C1 = ConstantExpr::getSExtOrBitCast(Idx0, CommonTy);
2210  Constant *C2 = ConstantExpr::getSExtOrBitCast(Combined, CommonTy);
2211  Combined = ConstantExpr::get(Instruction::Add, C1, C2);
2212  } else {
2213  Combined =
2214  ConstantExpr::get(Instruction::Add, Idx0, Combined);
2215  }
2216  }
2217 
2218  NewIndices.push_back(Combined);
2219  NewIndices.append(Idxs.begin() + 1, Idxs.end());
2220 
2221  // The combined GEP normally inherits its index inrange attribute from
2222  // the inner GEP, but if the inner GEP's last index was adjusted by the
2223  // outer GEP, any inbounds attribute on that index is invalidated.
2224  Optional<unsigned> IRIndex = cast<GEPOperator>(CE)->getInRangeIndex();
2225  if (IRIndex && *IRIndex == CE->getNumOperands() - 2 && !Idx0->isNullValue())
2226  IRIndex = None;
2227 
2229  cast<GEPOperator>(CE)->getSourceElementType(), CE->getOperand(0),
2230  NewIndices, InBounds && cast<GEPOperator>(CE)->isInBounds(),
2231  IRIndex);
2232  }
2233  }
2234 
2235  // Attempt to fold casts to the same type away. For example, folding:
2236  //
2237  // i32* getelementptr ([2 x i32]* bitcast ([3 x i32]* %X to [2 x i32]*),
2238  // i64 0, i64 0)
2239  // into:
2240  //
2241  // i32* getelementptr ([3 x i32]* %X, i64 0, i64 0)
2242  //
2243  // Don't fold if the cast is changing address spaces.
2244  if (CE->isCast() && Idxs.size() > 1 && Idx0->isNullValue()) {
2245  PointerType *SrcPtrTy =
2246  dyn_cast<PointerType>(CE->getOperand(0)->getType());
2247  PointerType *DstPtrTy = dyn_cast<PointerType>(CE->getType());
2248  if (SrcPtrTy && DstPtrTy) {
2249  ArrayType *SrcArrayTy =
2250  dyn_cast<ArrayType>(SrcPtrTy->getElementType());
2251  ArrayType *DstArrayTy =
2252  dyn_cast<ArrayType>(DstPtrTy->getElementType());
2253  if (SrcArrayTy && DstArrayTy
2254  && SrcArrayTy->getElementType() == DstArrayTy->getElementType()
2255  && SrcPtrTy->getAddressSpace() == DstPtrTy->getAddressSpace())
2256  return ConstantExpr::getGetElementPtr(SrcArrayTy,
2257  (Constant *)CE->getOperand(0),
2258  Idxs, InBounds, InRangeIndex);
2259  }
2260  }
2261  }
2262 
2263  // Check to see if any array indices are not within the corresponding
2264  // notional array or vector bounds. If so, try to determine if they can be
2265  // factored out into preceding dimensions.
2267  Type *Ty = PointeeTy;
2268  Type *Prev = C->getType();
2269  bool Unknown =
2270  !isa<ConstantInt>(Idxs[0]) && !isa<ConstantDataVector>(Idxs[0]);
2271  for (unsigned i = 1, e = Idxs.size(); i != e;
2272  Prev = Ty, Ty = cast<CompositeType>(Ty)->getTypeAtIndex(Idxs[i]), ++i) {
2273  if (!isa<ConstantInt>(Idxs[i]) && !isa<ConstantDataVector>(Idxs[i])) {
2274  // We don't know if it's in range or not.
2275  Unknown = true;
2276  continue;
2277  }
2278  if (!isa<ConstantInt>(Idxs[i - 1]) && !isa<ConstantDataVector>(Idxs[i - 1]))
2279  // Skip if the type of the previous index is not supported.
2280  continue;
2281  if (InRangeIndex && i == *InRangeIndex + 1) {
2282  // If an index is marked inrange, we cannot apply this canonicalization to
2283  // the following index, as that will cause the inrange index to point to
2284  // the wrong element.
2285  continue;
2286  }
2287  if (isa<StructType>(Ty)) {
2288  // The verify makes sure that GEPs into a struct are in range.
2289  continue;
2290  }
2291  auto *STy = cast<SequentialType>(Ty);
2292  if (isa<VectorType>(STy)) {
2293  // There can be awkward padding in after a non-power of two vector.
2294  Unknown = true;
2295  continue;
2296  }
2297  if (ConstantInt *CI = dyn_cast<ConstantInt>(Idxs[i])) {
2298  if (isIndexInRangeOfArrayType(STy->getNumElements(), CI))
2299  // It's in range, skip to the next index.
2300  continue;
2301  if (CI->getSExtValue() < 0) {
2302  // It's out of range and negative, don't try to factor it.
2303  Unknown = true;
2304  continue;
2305  }
2306  } else {
2307  auto *CV = cast<ConstantDataVector>(Idxs[i]);
2308  bool InRange = true;
2309  for (unsigned I = 0, E = CV->getNumElements(); I != E; ++I) {
2310  auto *CI = cast<ConstantInt>(CV->getElementAsConstant(I));
2311  InRange &= isIndexInRangeOfArrayType(STy->getNumElements(), CI);
2312  if (CI->getSExtValue() < 0) {
2313  Unknown = true;
2314  break;
2315  }
2316  }
2317  if (InRange || Unknown)
2318  // It's in range, skip to the next index.
2319  // It's out of range and negative, don't try to factor it.
2320  continue;
2321  }
2322  if (isa<StructType>(Prev)) {
2323  // It's out of range, but the prior dimension is a struct
2324  // so we can't do anything about it.
2325  Unknown = true;
2326  continue;
2327  }
2328  // It's out of range, but we can factor it into the prior
2329  // dimension.
2330  NewIdxs.resize(Idxs.size());
2331  // Determine the number of elements in our sequential type.
2332  uint64_t NumElements = STy->getArrayNumElements();
2333 
2334  // Expand the current index or the previous index to a vector from a scalar
2335  // if necessary.
2336  Constant *CurrIdx = cast<Constant>(Idxs[i]);
2337  auto *PrevIdx =
2338  NewIdxs[i - 1] ? NewIdxs[i - 1] : cast<Constant>(Idxs[i - 1]);
2339  bool IsCurrIdxVector = CurrIdx->getType()->isVectorTy();
2340  bool IsPrevIdxVector = PrevIdx->getType()->isVectorTy();
2341  bool UseVector = IsCurrIdxVector || IsPrevIdxVector;
2342 
2343  if (!IsCurrIdxVector && IsPrevIdxVector)
2344  CurrIdx = ConstantDataVector::getSplat(
2345  PrevIdx->getType()->getVectorNumElements(), CurrIdx);
2346 
2347  if (!IsPrevIdxVector && IsCurrIdxVector)
2348  PrevIdx = ConstantDataVector::getSplat(
2349  CurrIdx->getType()->getVectorNumElements(), PrevIdx);
2350 
2351  Constant *Factor =
2352  ConstantInt::get(CurrIdx->getType()->getScalarType(), NumElements);
2353  if (UseVector)
2355  IsPrevIdxVector ? PrevIdx->getType()->getVectorNumElements()
2356  : CurrIdx->getType()->getVectorNumElements(),
2357  Factor);
2358 
2359  NewIdxs[i] = ConstantExpr::getSRem(CurrIdx, Factor);
2360 
2361  Constant *Div = ConstantExpr::getSDiv(CurrIdx, Factor);
2362 
2363  unsigned CommonExtendedWidth =
2364  std::max(PrevIdx->getType()->getScalarSizeInBits(),
2365  Div->getType()->getScalarSizeInBits());
2366  CommonExtendedWidth = std::max(CommonExtendedWidth, 64U);
2367 
2368  // Before adding, extend both operands to i64 to avoid
2369  // overflow trouble.
2370  Type *ExtendedTy = Type::getIntNTy(Div->getContext(), CommonExtendedWidth);
2371  if (UseVector)
2372  ExtendedTy = VectorType::get(
2373  ExtendedTy, IsPrevIdxVector
2374  ? PrevIdx->getType()->getVectorNumElements()
2375  : CurrIdx->getType()->getVectorNumElements());
2376 
2377  if (!PrevIdx->getType()->isIntOrIntVectorTy(CommonExtendedWidth))
2378  PrevIdx = ConstantExpr::getSExt(PrevIdx, ExtendedTy);
2379 
2380  if (!Div->getType()->isIntOrIntVectorTy(CommonExtendedWidth))
2381  Div = ConstantExpr::getSExt(Div, ExtendedTy);
2382 
2383  NewIdxs[i - 1] = ConstantExpr::getAdd(PrevIdx, Div);
2384  }
2385 
2386  // If we did any factoring, start over with the adjusted indices.
2387  if (!NewIdxs.empty()) {
2388  for (unsigned i = 0, e = Idxs.size(); i != e; ++i)
2389  if (!NewIdxs[i]) NewIdxs[i] = cast<Constant>(Idxs[i]);
2390  return ConstantExpr::getGetElementPtr(PointeeTy, C, NewIdxs, InBounds,
2391  InRangeIndex);
2392  }
2393 
2394  // If all indices are known integers and normalized, we can do a simple
2395  // check for the "inbounds" property.
2396  if (!Unknown && !InBounds)
2397  if (auto *GV = dyn_cast<GlobalVariable>(C))
2398  if (!GV->hasExternalWeakLinkage() && isInBoundsIndices(Idxs))
2399  return ConstantExpr::getGetElementPtr(PointeeTy, C, Idxs,
2400  /*InBounds=*/true, InRangeIndex);
2401 
2402  return nullptr;
2403 }
static unsigned getBitWidth(Type *Ty, const DataLayout &DL)
Returns the bitwidth of the given scalar or pointer type.
Type * getVectorElementType() const
Definition: Type.h:370
uint64_t CallInst * C
static const fltSemantics & IEEEquad() LLVM_READNONE
Definition: APFloat.cpp:125
static Constant * FoldBitCast(Constant *V, Type *DestTy)
static ConstantInt * getFalse(LLVMContext &Context)
Definition: Constants.cpp:594
class_match< UndefValue > m_Undef()
Match an arbitrary undef constant.
Definition: PatternMatch.h:86
bool isAllOnesValue() const
Return true if this is the value that would be returned by getAllOnesValue.
Definition: Constants.cpp:99
static IntegerType * getInt1Ty(LLVMContext &C)
Definition: Type.cpp:172
opStatus convertFromAPInt(const APInt &Input, bool IsSigned, roundingMode RM)
Definition: APFloat.h:1076
unsigned getOpcode() const
Return the opcode at the root of this constant expression.
Definition: Constants.h:1209
uint64_t getZExtValue() const
Get zero extended value.
Definition: APInt.h:1562
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:375
This class represents lattice values for constants.
Definition: AllocatorList.h:23
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:65
static Constant * getGetElementPtr(Type *Ty, Constant *C, ArrayRef< Constant *> IdxList, bool InBounds=false, Optional< unsigned > InRangeIndex=None, Type *OnlyIfReducedTy=nullptr)
Getelementptr form.
Definition: Constants.h:1153
bool isSized(SmallPtrSetImpl< Type *> *Visited=nullptr) const
Return true if it makes sense to take the size of this type.
Definition: Type.h:264
iterator begin() const
Definition: ArrayRef.h:136
APInt sdiv(const APInt &RHS) const
Signed division function for APInt.
Definition: APInt.cpp:1590
bool isFP128Ty() const
Return true if this is &#39;fp128&#39;.
Definition: Type.h:155
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:1203
APInt udiv(const APInt &RHS) const
Unsigned division operation.
Definition: APInt.cpp:1519
static APInt getLowBitsSet(unsigned numBits, unsigned loBitsSet)
Get a value with low bits set.
Definition: APInt.h:647
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:629
gep_type_iterator gep_type_end(const User *GEP)
unsigned less or equal
Definition: InstrTypes.h:672
unsigned less than
Definition: InstrTypes.h:671
Constant * ConstantFoldCastInstruction(unsigned opcode, Constant *V, Type *DestTy)
static Constant * getExtractElement(Constant *Vec, Constant *Idx, Type *OnlyIfReducedTy=nullptr)
Definition: Constants.cpp:2112
0 1 0 0 True if ordered and less than
Definition: InstrTypes.h:652
LLVMContext & getContext() const
All values hold a context through their type.
Definition: Value.cpp:709
1 1 1 0 True if unordered or not equal
Definition: InstrTypes.h:662
bool sgt(const APInt &RHS) const
Signed greather than comparison.
Definition: APInt.h:1273
APInt trunc(unsigned width) const
Truncate to new width.
Definition: APInt.cpp:810
static IntegerType * getInt64Ty(LLVMContext &C)
Definition: Type.cpp:176
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:1965
bool isVectorTy() const
True if this is an instance of VectorType.
Definition: Type.h:229
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:369
bool sle(const APInt &RHS) const
Signed less or equal comparison.
Definition: APInt.h:1238
bool isPPC_FP128Ty() const
Return true if this is powerpc long double.
Definition: Type.h:158
static Constant * get(ArrayType *T, ArrayRef< Constant *> V)
Definition: Constants.cpp:992
unsigned getBitWidth() const
Return the number of bits in the APInt.
Definition: APInt.h:1508
unsigned getPointerAlignment(const DataLayout &DL) const
Returns an alignment of the pointer value.
Definition: Value.cpp:646
LLVMContext & getContext() const
Return the LLVMContext in which this type was uniqued.
Definition: Type.h:129
static Constant * getNullValue(Type *Ty)
Constructor to create a &#39;0&#39; constant of arbitrary type.
Definition: Constants.cpp:274
static Constant * getAdd(Constant *C1, Constant *C2, bool HasNUW=false, bool HasNSW=false)
Definition: Constants.cpp:2247
opStatus convertToInteger(MutableArrayRef< integerPart > Input, unsigned int Width, bool IsSigned, roundingMode RM, bool *IsExact) const
Definition: APFloat.h:1068
1 0 0 1 True if unordered or equal
Definition: InstrTypes.h:657
static bool InRange(int64_t Value, unsigned short Shift, int LBound, int HBound)
opStatus divide(const APFloat &RHS, roundingMode RM)
Definition: APFloat.h:967
The address of a basic block.
Definition: Constants.h:839
bool match(Val *V, const Pattern &P)
Definition: PatternMatch.h:47
1 0 0 0 True if unordered: isnan(X) | isnan(Y)
Definition: InstrTypes.h:656
bool isSigned() const
Definition: InstrTypes.h:816
Predicate getInversePredicate() const
For example, EQ -> NE, UGT -> ULE, SLT -> SGE, OEQ -> UNE, UGT -> OLE, OLT -> UGE, etc.
Definition: InstrTypes.h:745
ArrayRef< T > makeArrayRef(const T &OneElt)
Construct an ArrayRef from a single element.
Definition: ArrayRef.h:450
bool isFloatingPointTy() const
Return true if this is one of the six floating-point types.
Definition: Type.h:161
APInt shl(unsigned shiftAmt) const
Left-shift function.
Definition: APInt.h:992
Class to represent struct types.
Definition: DerivedTypes.h:232
static Constant * getLShr(Constant *C1, Constant *C2, bool isExact=false)
Definition: Constants.cpp:2325
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 Optional< unsigned > getOpcode(ArrayRef< VPValue *> Values)
Returns the opcode of Values or ~0 if they do not all agree.
Definition: VPlanSLP.cpp:196
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:196
0 1 0 1 True if ordered and less than or equal
Definition: InstrTypes.h:653
static Constant * getSExt(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1660
uint64_t getNumElements() const
Definition: DerivedTypes.h:390
void lshrInPlace(unsigned ShiftAmt)
Logical right-shift this APInt by ShiftAmt in place.
Definition: APInt.h:977
bool isOne() const
This is just a convenience method to make client code smaller for a common case.
Definition: Constants.h:200
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:1924
bool isNullValue() const
Return true if this is the value that would be returned by getNullValue.
Definition: Constants.cpp:84
A constant value that is initialized with an expression using other constant values.
Definition: Constants.h:888
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:244
bool isFirstClassType() const
Return true if the type is "first class", meaning it is a valid type for a Value. ...
Definition: Type.h:243
opStatus convert(const fltSemantics &ToSemantics, roundingMode RM, bool *losesInfo)
Definition: APFloat.cpp:4446
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:400
static Constant * getSelect(Constant *C, Constant *V1, Constant *V2, Type *OnlyIfReducedTy=nullptr)
Select constant expr.
Definition: Constants.cpp:1987
bool isIntOrPtrTy() const
Return true if this is an integer type or a pointer type.
Definition: Type.h:211
const APInt & getValue() const
Return the constant as an APInt value reference.
Definition: Constants.h:137
bool isGEPWithNoNotionalOverIndexing() const
Return true if this is a getelementptr expression and all the index operands are compile-time known i...
Definition: Constants.cpp:1162
opStatus subtract(const APFloat &RHS, roundingMode RM)
Definition: APFloat.h:949
cmpResult
IEEE-754R 5.11: Floating Point Comparison Relations.
Definition: APFloat.h:165
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:202
static const fltSemantics & IEEEdouble() LLVM_READNONE
Definition: APFloat.cpp:122
unsigned getAlignment() const
Definition: Globals.cpp:96
Value * getOperand(unsigned i) const
Definition: User.h:169
Class to represent pointers.
Definition: DerivedTypes.h:498
Constant * getAggregateElement(unsigned Elt) const
For aggregates (struct/array/vector) return the constant that corresponds to the specified element if...
Definition: Constants.cpp:344
Type * getScalarType() const
If this is a vector type, return the element type, otherwise return &#39;this&#39;.
Definition: Type.h:303
static Constant * getBitCast(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1782
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:146
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:507
bool isAllOnesValue() const
Determine if all bits are set.
Definition: APInt.h:395
apint_match m_APInt(const APInt *&Res)
Match a ConstantInt or splatted ConstantVector, binding the specified pointer to the contained APInt...
Definition: PatternMatch.h:175
static ConstantPointerNull * get(PointerType *T)
Static factory methods - Return objects of the specified value.
Definition: Constants.cpp:1410
APInt urem(const APInt &RHS) const
Unsigned remainder operation.
Definition: APInt.cpp:1612
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:45
bool ult(const APInt &RHS) const
Unsigned less than comparison.
Definition: APInt.h:1184
size_t size() const
size - Get the array size.
Definition: ArrayRef.h:148
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
This is an important base class in LLVM.
Definition: Constant.h:41
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:2306
ConstantFP - Floating Point Values [float, double].
Definition: Constants.h:263
static Constant * getSExtOrBitCast(Constant *C, Type *Ty)
Definition: Constants.cpp:1584
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:442
bool isHalfTy() const
Return true if this is &#39;half&#39;, a 16-bit IEEE fp type.
Definition: Type.h:143
Predicate
This enumeration lists the possible predicates for CmpInst subclasses.
Definition: InstrTypes.h:646
bool isBinaryOp() const
Definition: Instruction.h:130
opStatus multiply(const APFloat &RHS, roundingMode RM)
Definition: APFloat.h:958
static Constant * get(StructType *T, ArrayRef< Constant *> V)
Definition: Constants.cpp:1053
0 1 1 1 True if ordered (no nans)
Definition: InstrTypes.h:655
unsigned getAddressSpace() const
Return the address space of the Pointer type.
Definition: DerivedTypes.h:526
bool isX86_MMXTy() const
Return true if this is X86 MMX.
Definition: Type.h:181
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:2062
static const fltSemantics & x87DoubleExtended() LLVM_READNONE
Definition: APFloat.cpp:128
Class to represent integer types.
Definition: DerivedTypes.h:39
Constant Vector Declarations.
Definition: Constants.h:499
static Constant * getSplat(unsigned NumElts, Constant *Elt)
Return a ConstantVector with the specified constant in each element.
Definition: Constants.cpp:2647
static Constant * getNot(Constant *C)
Definition: Constants.cpp:2241
static Constant * getAllOnesValue(Type *Ty)
Definition: Constants.cpp:328
1 1 1 1 Always true (always folded)
Definition: InstrTypes.h:663
static UndefValue * get(Type *T)
Static factory methods - Return an &#39;undef&#39; object of the specified type.
Definition: Constants.cpp:1424
bool isCast() const
Definition: Instruction.h:133
size_t size() const
Definition: SmallVector.h:52
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:661
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
const T * data() const
Definition: ArrayRef.h:145
APInt lshr(unsigned shiftAmt) const
Logical right-shift function.
Definition: APInt.h:970
signed greater than
Definition: InstrTypes.h:673
hexagon gen pred
static Constant * getFCmp(unsigned short pred, Constant *LHS, Constant *RHS, bool OnlyIfReduced=false)
Definition: Constants.cpp:2087
This is the superclass of the array and vector type classes.
Definition: DerivedTypes.h:374
0 0 1 0 True if ordered and greater than
Definition: InstrTypes.h:650
static Constant * getPointerCast(Constant *C, Type *Ty)
Create a BitCast, AddrSpaceCast, or a PtrToInt cast constant expression.
Definition: Constants.cpp:1596
APInt ashr(unsigned ShiftAmt) const
Arithmetic right-shift function.
Definition: APInt.h:946
static Constant * getSplat(unsigned NumElts, Constant *Elt)
Return a ConstantVector with the specified constant in each element.
Definition: Constants.cpp:1128
static IntegerType * get(LLVMContext &C, unsigned NumBits)
This static method is the primary way of constructing an IntegerType.
Definition: Type.cpp:239
static const fltSemantics & IEEEsingle() LLVM_READNONE
Definition: APFloat.cpp:119
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:191
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:83
static const fltSemantics & IEEEhalf() LLVM_READNONE
Definition: APFloat.cpp:116
static Constant * getSDiv(Constant *C1, Constant *C2, bool isExact=false)
Definition: Constants.cpp:2285
unsigned getScalarSizeInBits() const LLVM_READONLY
If this is a vector type, return the getPrimitiveSizeInBits value for the element type...
Definition: Type.cpp:129
1 1 0 0 True if unordered or less than
Definition: InstrTypes.h:660
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:841
Module.h This file contains the declarations for the Module class.
iterator end() const
Definition: ArrayRef.h:137
static Constant * getNUWMul(Constant *C1, Constant *C2)
Definition: Constants.h:996
signed less than
Definition: InstrTypes.h:675
static IntegerType * getIntNTy(LLVMContext &C, unsigned N)
Definition: Type.cpp:179
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:1646
static Constant * get(Type *Ty, uint64_t V, bool isSigned=false)
If Ty is a vector type, return a Constant with a splat of the given value.
Definition: Constants.cpp:631
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:694
bool uge(const APInt &RHS) const
Unsigned greater or equal comparison.
Definition: APInt.h:1292
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:587
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:491
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:538
unsigned getVectorNumElements() const
Definition: DerivedTypes.h:493
bool isIntPredicate() const
Definition: InstrTypes.h:739
bool isTrueWhenEqual() const
This is just a convenience.
Definition: InstrTypes.h:841
signed less or equal
Definition: InstrTypes.h:676
Class to represent vector types.
Definition: DerivedTypes.h:424
Class for arbitrary precision integers.
Definition: APInt.h:69
bool ule(const APInt &RHS) const
Unsigned less or equal comparison.
Definition: APInt.h:1222
bool sge(const APInt &RHS) const
Signed greater or equal comparison.
Definition: APInt.h:1308
static Constant * getCast(unsigned ops, Constant *C, Type *Ty, bool OnlyIfReduced=false)
Convenience function for getting a Cast operation.
Definition: Constants.cpp:1539
opStatus mod(const APFloat &RHS)
Definition: APFloat.h:985
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:178
void append(in_iter in_start, in_iter in_end)
Add the specified range to the end of the SmallVector.
Definition: SmallVector.h:387
bool isX86_FP80Ty() const
Return true if this is x86 long double.
Definition: Type.h:152
static const fltSemantics & PPCDoubleDouble() LLVM_READNONE
Definition: APFloat.cpp:134
Constant * ConstantFoldCompareInstruction(unsigned short predicate, Constant *C1, Constant *C2)
opStatus add(const APFloat &RHS, roundingMode RM)
Definition: APFloat.h:940
bool ugt(const APInt &RHS) const
Unsigned greather than comparison.
Definition: APInt.h:1254
Constant * ConstantFoldSelectInstruction(Constant *Cond, Constant *V1, Constant *V2)
Attempt to constant fold a select instruction with the specified operands.
static Constant * getNaN(Type *Ty, bool Negative=false, uint64_t Payload=0)
Definition: Constants.cpp:735
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:175
unsigned getIntegerBitWidth() const
Definition: DerivedTypes.h:96
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:55
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:1947
unsigned greater or equal
Definition: InstrTypes.h:670
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:1682
static Constant * getInBoundsGetElementPtr(Type *Ty, Constant *C, ArrayRef< Constant *> IdxList)
Create an "inbounds" getelementptr.
Definition: Constants.h:1180
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:2310
static const fltSemantics & Bogus() LLVM_READNONE
A Pseudo fltsemantic used to construct APFloats that cannot conflict with anything real...
Definition: APFloat.cpp:131
bool isZero() const
This is just a convenience method to make client code smaller for a common code.
Definition: Constants.h:192
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:654
LLVM_NODISCARD std::enable_if<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:332
1 0 1 0 True if unordered or greater than
Definition: InstrTypes.h:658
Constant * ConstantFoldGetElementPtr(Type *Ty, Constant *C, bool InBounds, Optional< unsigned > InRangeIndex, ArrayRef< Value *> Idxs)
bool isFPOrFPVectorTy() const
Return true if this is a FP type or a vector of FP.
Definition: Type.h:184
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())
unsigned getMinSignedBits() const
Get the minimum bit size for this signed APInt.
Definition: APInt.h:1551
static Constant * getSRem(Constant *C1, Constant *C2)
Definition: Constants.cpp:2298
unsigned getPrimitiveSizeInBits() const LLVM_READONLY
Return the basic size of this type if it is a primitive type.
Definition: Type.cpp:114
0 0 0 1 True if ordered and equal
Definition: InstrTypes.h:649
Module * getParent()
Get the module that this global value is contained inside of...
Definition: GlobalValue.h:565
LLVM Value Representation.
Definition: Value.h:72
1 0 1 1 True if unordered, greater than, or equal
Definition: InstrTypes.h:659
cst_pred_ty< is_one > m_One()
Match an integer 1 or a vector with all elements equal to 1.
Definition: PatternMatch.h:354
static VectorType * get(Type *ElementType, unsigned NumElements)
This static method is the primary way to construct an VectorType.
Definition: Type.cpp:605
#define LLVM_FALLTHROUGH
LLVM_FALLTHROUGH - Mark fallthrough cases in switch statements.
Definition: Compiler.h:250
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:80
bool isCast() const
Return true if this is a convert constant expression.
Definition: Constants.cpp:1154
Type * getElementType() const
Definition: DerivedTypes.h:391
unsigned greater than
Definition: InstrTypes.h:669
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:761
Type * getSourceElementType() const
Definition: Operator.cpp:22
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:97
static APInt getNullValue(unsigned numBits)
Get the &#39;0&#39; value.
Definition: APInt.h:568
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:156
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:1934
static Constant * getMul(Constant *C1, Constant *C2, bool HasNUW=false, bool HasNSW=false)
Definition: Constants.cpp:2269
0 0 1 1 True if ordered and greater than or equal
Definition: InstrTypes.h:651
bool isDoubleTy() const
Return true if this is &#39;double&#39;, a 64-bit IEEE fp type.
Definition: Type.h:149
static Constant * get(ArrayRef< Constant *> V)
Definition: Constants.cpp:1088
Type * getElementType() const
Definition: DerivedTypes.h:517
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:648
signed greater or equal
Definition: InstrTypes.h:674
bool empty() const
empty - Check if the array is empty.
Definition: ArrayRef.h:143
cmpResult compare(const APFloat &RHS) const
Definition: APFloat.h:1101
static Constant * getXor(Constant *C1, Constant *C2)
Definition: Constants.cpp:2314
const fltSemantics & getFltSemantics() const
Definition: Type.h:168
gep_type_iterator gep_type_begin(const User *GEP)
void resize(size_type N)
Definition: SmallVector.h:344
static Constant * get(unsigned Opcode, Constant *C1, unsigned Flags=0, Type *OnlyIfReducedTy=nullptr)
get - Return a unary operator constant expression, folding if possible.
Definition: Constants.cpp:1815