1 //===- ConstantFold.cpp - LLVM constant folder ----------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements folding of constants for LLVM. This implements the
11 // (internal) ConstantFold.h interface, which is used by the
12 // ConstantExpr::get* methods to automatically fold constants when possible.
14 // The current constant folding implementation is implemented in two pieces: the
15 // pieces that don't need TargetData, and the pieces that do. This is to avoid
16 // a dependence in VMCore on Target.
18 //===----------------------------------------------------------------------===//
20 #include "ConstantFold.h"
21 #include "llvm/Constants.h"
22 #include "llvm/Instructions.h"
23 #include "llvm/DerivedTypes.h"
24 #include "llvm/Function.h"
25 #include "llvm/GlobalAlias.h"
26 #include "llvm/GlobalVariable.h"
27 #include "llvm/ADT/SmallVector.h"
28 #include "llvm/Support/Compiler.h"
29 #include "llvm/Support/ErrorHandling.h"
30 #include "llvm/Support/GetElementPtrTypeIterator.h"
31 #include "llvm/Support/ManagedStatic.h"
32 #include "llvm/Support/MathExtras.h"
36 //===----------------------------------------------------------------------===//
37 // ConstantFold*Instruction Implementations
38 //===----------------------------------------------------------------------===//
40 /// BitCastConstantVector - Convert the specified ConstantVector node to the
41 /// specified vector type. At this point, we know that the elements of the
42 /// input vector constant are all simple integer or FP values.
43 static Constant *BitCastConstantVector(ConstantVector *CV,
44 const VectorType *DstTy) {
45 // If this cast changes element count then we can't handle it here:
46 // doing so requires endianness information. This should be handled by
47 // Analysis/ConstantFolding.cpp
48 unsigned NumElts = DstTy->getNumElements();
49 if (NumElts != CV->getNumOperands())
52 // Check to verify that all elements of the input are simple.
53 for (unsigned i = 0; i != NumElts; ++i) {
54 if (!isa<ConstantInt>(CV->getOperand(i)) &&
55 !isa<ConstantFP>(CV->getOperand(i)))
59 // Bitcast each element now.
60 std::vector<Constant*> Result;
61 const Type *DstEltTy = DstTy->getElementType();
62 for (unsigned i = 0; i != NumElts; ++i)
63 Result.push_back(ConstantExpr::getBitCast(CV->getOperand(i),
65 return ConstantVector::get(Result);
68 /// This function determines which opcode to use to fold two constant cast
69 /// expressions together. It uses CastInst::isEliminableCastPair to determine
70 /// the opcode. Consequently its just a wrapper around that function.
71 /// @brief Determine if it is valid to fold a cast of a cast
74 unsigned opc, ///< opcode of the second cast constant expression
75 ConstantExpr *Op, ///< the first cast constant expression
76 const Type *DstTy ///< desintation type of the first cast
78 assert(Op && Op->isCast() && "Can't fold cast of cast without a cast!");
79 assert(DstTy && DstTy->isFirstClassType() && "Invalid cast destination type");
80 assert(CastInst::isCast(opc) && "Invalid cast opcode");
82 // The the types and opcodes for the two Cast constant expressions
83 const Type *SrcTy = Op->getOperand(0)->getType();
84 const Type *MidTy = Op->getType();
85 Instruction::CastOps firstOp = Instruction::CastOps(Op->getOpcode());
86 Instruction::CastOps secondOp = Instruction::CastOps(opc);
88 // Let CastInst::isEliminableCastPair do the heavy lifting.
89 return CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy, DstTy,
90 Type::getInt64Ty(DstTy->getContext()));
93 static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
94 const Type *SrcTy = V->getType();
96 return V; // no-op cast
98 // Check to see if we are casting a pointer to an aggregate to a pointer to
99 // the first element. If so, return the appropriate GEP instruction.
100 if (const PointerType *PTy = dyn_cast<PointerType>(V->getType()))
101 if (const PointerType *DPTy = dyn_cast<PointerType>(DestTy))
102 if (PTy->getAddressSpace() == DPTy->getAddressSpace()) {
103 SmallVector<Value*, 8> IdxList;
105 Constant::getNullValue(Type::getInt32Ty(DPTy->getContext()));
106 IdxList.push_back(Zero);
107 const Type *ElTy = PTy->getElementType();
108 while (ElTy != DPTy->getElementType()) {
109 if (const StructType *STy = dyn_cast<StructType>(ElTy)) {
110 if (STy->getNumElements() == 0) break;
111 ElTy = STy->getElementType(0);
112 IdxList.push_back(Zero);
113 } else if (const SequentialType *STy =
114 dyn_cast<SequentialType>(ElTy)) {
115 if (isa<PointerType>(ElTy)) break; // Can't index into pointers!
116 ElTy = STy->getElementType();
117 IdxList.push_back(Zero);
123 if (ElTy == DPTy->getElementType())
124 // This GEP is inbounds because all indices are zero.
125 return ConstantExpr::getInBoundsGetElementPtr(V, &IdxList[0],
129 // Handle casts from one vector constant to another. We know that the src
130 // and dest type have the same size (otherwise its an illegal cast).
131 if (const VectorType *DestPTy = dyn_cast<VectorType>(DestTy)) {
132 if (const VectorType *SrcTy = dyn_cast<VectorType>(V->getType())) {
133 assert(DestPTy->getBitWidth() == SrcTy->getBitWidth() &&
134 "Not cast between same sized vectors!");
136 // First, check for null. Undef is already handled.
137 if (isa<ConstantAggregateZero>(V))
138 return Constant::getNullValue(DestTy);
140 if (ConstantVector *CV = dyn_cast<ConstantVector>(V))
141 return BitCastConstantVector(CV, DestPTy);
144 // Canonicalize scalar-to-vector bitcasts into vector-to-vector bitcasts
145 // This allows for other simplifications (although some of them
146 // can only be handled by Analysis/ConstantFolding.cpp).
147 if (isa<ConstantInt>(V) || isa<ConstantFP>(V))
148 return ConstantExpr::getBitCast(ConstantVector::get(&V, 1), DestPTy);
151 // Finally, implement bitcast folding now. The code below doesn't handle
153 if (isa<ConstantPointerNull>(V)) // ptr->ptr cast.
154 return ConstantPointerNull::get(cast<PointerType>(DestTy));
156 // Handle integral constant input.
157 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
158 if (DestTy->isIntegerTy())
159 // Integral -> Integral. This is a no-op because the bit widths must
160 // be the same. Consequently, we just fold to V.
163 if (DestTy->isFloatingPointTy())
164 return ConstantFP::get(DestTy->getContext(),
165 APFloat(CI->getValue(),
166 !DestTy->isPPC_FP128Ty()));
168 // Otherwise, can't fold this (vector?)
172 // Handle ConstantFP input: FP -> Integral.
173 if (ConstantFP *FP = dyn_cast<ConstantFP>(V))
174 return ConstantInt::get(FP->getContext(),
175 FP->getValueAPF().bitcastToAPInt());
181 /// ExtractConstantBytes - V is an integer constant which only has a subset of
182 /// its bytes used. The bytes used are indicated by ByteStart (which is the
183 /// first byte used, counting from the least significant byte) and ByteSize,
184 /// which is the number of bytes used.
186 /// This function analyzes the specified constant to see if the specified byte
187 /// range can be returned as a simplified constant. If so, the constant is
188 /// returned, otherwise null is returned.
190 static Constant *ExtractConstantBytes(Constant *C, unsigned ByteStart,
192 assert(isa<IntegerType>(C->getType()) &&
193 (cast<IntegerType>(C->getType())->getBitWidth() & 7) == 0 &&
194 "Non-byte sized integer input");
195 unsigned CSize = cast<IntegerType>(C->getType())->getBitWidth()/8;
196 assert(ByteSize && "Must be accessing some piece");
197 assert(ByteStart+ByteSize <= CSize && "Extracting invalid piece from input");
198 assert(ByteSize != CSize && "Should not extract everything");
200 // Constant Integers are simple.
201 if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
202 APInt V = CI->getValue();
204 V = V.lshr(ByteStart*8);
206 return ConstantInt::get(CI->getContext(), V);
209 // In the input is a constant expr, we might be able to recursively simplify.
210 // If not, we definitely can't do anything.
211 ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
212 if (CE == 0) return 0;
214 switch (CE->getOpcode()) {
216 case Instruction::Or: {
217 Constant *RHS = ExtractConstantBytes(CE->getOperand(1), ByteStart,ByteSize);
222 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS))
223 if (RHSC->isAllOnesValue())
226 Constant *LHS = ExtractConstantBytes(CE->getOperand(0), ByteStart,ByteSize);
229 return ConstantExpr::getOr(LHS, RHS);
231 case Instruction::And: {
232 Constant *RHS = ExtractConstantBytes(CE->getOperand(1), ByteStart,ByteSize);
237 if (RHS->isNullValue())
240 Constant *LHS = ExtractConstantBytes(CE->getOperand(0), ByteStart,ByteSize);
243 return ConstantExpr::getAnd(LHS, RHS);
245 case Instruction::LShr: {
246 ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
249 unsigned ShAmt = Amt->getZExtValue();
250 // Cannot analyze non-byte shifts.
251 if ((ShAmt & 7) != 0)
255 // If the extract is known to be all zeros, return zero.
256 if (ByteStart >= CSize-ShAmt)
257 return Constant::getNullValue(IntegerType::get(CE->getContext(),
259 // If the extract is known to be fully in the input, extract it.
260 if (ByteStart+ByteSize+ShAmt <= CSize)
261 return ExtractConstantBytes(CE->getOperand(0), ByteStart+ShAmt, ByteSize);
263 // TODO: Handle the 'partially zero' case.
267 case Instruction::Shl: {
268 ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
271 unsigned ShAmt = Amt->getZExtValue();
272 // Cannot analyze non-byte shifts.
273 if ((ShAmt & 7) != 0)
277 // If the extract is known to be all zeros, return zero.
278 if (ByteStart+ByteSize <= ShAmt)
279 return Constant::getNullValue(IntegerType::get(CE->getContext(),
281 // If the extract is known to be fully in the input, extract it.
282 if (ByteStart >= ShAmt)
283 return ExtractConstantBytes(CE->getOperand(0), ByteStart-ShAmt, ByteSize);
285 // TODO: Handle the 'partially zero' case.
289 case Instruction::ZExt: {
290 unsigned SrcBitSize =
291 cast<IntegerType>(CE->getOperand(0)->getType())->getBitWidth();
293 // If extracting something that is completely zero, return 0.
294 if (ByteStart*8 >= SrcBitSize)
295 return Constant::getNullValue(IntegerType::get(CE->getContext(),
298 // If exactly extracting the input, return it.
299 if (ByteStart == 0 && ByteSize*8 == SrcBitSize)
300 return CE->getOperand(0);
302 // If extracting something completely in the input, if if the input is a
303 // multiple of 8 bits, recurse.
304 if ((SrcBitSize&7) == 0 && (ByteStart+ByteSize)*8 <= SrcBitSize)
305 return ExtractConstantBytes(CE->getOperand(0), ByteStart, ByteSize);
307 // Otherwise, if extracting a subset of the input, which is not multiple of
308 // 8 bits, do a shift and trunc to get the bits.
309 if ((ByteStart+ByteSize)*8 < SrcBitSize) {
310 assert((SrcBitSize&7) && "Shouldn't get byte sized case here");
311 Constant *Res = CE->getOperand(0);
313 Res = ConstantExpr::getLShr(Res,
314 ConstantInt::get(Res->getType(), ByteStart*8));
315 return ConstantExpr::getTrunc(Res, IntegerType::get(C->getContext(),
319 // TODO: Handle the 'partially zero' case.
325 /// getFoldedSizeOf - Return a ConstantExpr with type DestTy for sizeof
326 /// on Ty, with any known factors factored out. If Folded is false,
327 /// return null if no factoring was possible, to avoid endlessly
328 /// bouncing an unfoldable expression back into the top-level folder.
330 static Constant *getFoldedSizeOf(const Type *Ty, const Type *DestTy,
332 if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
333 Constant *N = ConstantInt::get(DestTy, ATy->getNumElements());
334 Constant *E = getFoldedSizeOf(ATy->getElementType(), DestTy, true);
335 return ConstantExpr::getNUWMul(E, N);
337 if (const VectorType *VTy = dyn_cast<VectorType>(Ty)) {
338 Constant *N = ConstantInt::get(DestTy, VTy->getNumElements());
339 Constant *E = getFoldedSizeOf(VTy->getElementType(), DestTy, true);
340 return ConstantExpr::getNUWMul(E, N);
342 if (const StructType *STy = dyn_cast<StructType>(Ty))
343 if (!STy->isPacked()) {
344 unsigned NumElems = STy->getNumElements();
345 // An empty struct has size zero.
347 return ConstantExpr::getNullValue(DestTy);
348 // Check for a struct with all members having the same size.
349 Constant *MemberSize =
350 getFoldedSizeOf(STy->getElementType(0), DestTy, true);
352 for (unsigned i = 1; i != NumElems; ++i)
354 getFoldedSizeOf(STy->getElementType(i), DestTy, true)) {
359 Constant *N = ConstantInt::get(DestTy, NumElems);
360 return ConstantExpr::getNUWMul(MemberSize, N);
364 // Pointer size doesn't depend on the pointee type, so canonicalize them
365 // to an arbitrary pointee.
366 if (const PointerType *PTy = dyn_cast<PointerType>(Ty))
367 if (!PTy->getElementType()->isIntegerTy(1))
369 getFoldedSizeOf(PointerType::get(IntegerType::get(PTy->getContext(), 1),
370 PTy->getAddressSpace()),
373 // If there's no interesting folding happening, bail so that we don't create
374 // a constant that looks like it needs folding but really doesn't.
378 // Base case: Get a regular sizeof expression.
379 Constant *C = ConstantExpr::getSizeOf(Ty);
380 C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
386 /// getFoldedAlignOf - Return a ConstantExpr with type DestTy for alignof
387 /// on Ty, with any known factors factored out. If Folded is false,
388 /// return null if no factoring was possible, to avoid endlessly
389 /// bouncing an unfoldable expression back into the top-level folder.
391 static Constant *getFoldedAlignOf(const Type *Ty, const Type *DestTy,
393 // The alignment of an array is equal to the alignment of the
394 // array element. Note that this is not always true for vectors.
395 if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
396 Constant *C = ConstantExpr::getAlignOf(ATy->getElementType());
397 C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
404 if (const StructType *STy = dyn_cast<StructType>(Ty)) {
405 // Packed structs always have an alignment of 1.
407 return ConstantInt::get(DestTy, 1);
409 // Otherwise, struct alignment is the maximum alignment of any member.
410 // Without target data, we can't compare much, but we can check to see
411 // if all the members have the same alignment.
412 unsigned NumElems = STy->getNumElements();
413 // An empty struct has minimal alignment.
415 return ConstantInt::get(DestTy, 1);
416 // Check for a struct with all members having the same alignment.
417 Constant *MemberAlign =
418 getFoldedAlignOf(STy->getElementType(0), DestTy, true);
420 for (unsigned i = 1; i != NumElems; ++i)
421 if (MemberAlign != getFoldedAlignOf(STy->getElementType(i), DestTy, true)) {
429 // Pointer alignment doesn't depend on the pointee type, so canonicalize them
430 // to an arbitrary pointee.
431 if (const PointerType *PTy = dyn_cast<PointerType>(Ty))
432 if (!PTy->getElementType()->isIntegerTy(1))
434 getFoldedAlignOf(PointerType::get(IntegerType::get(PTy->getContext(),
436 PTy->getAddressSpace()),
439 // If there's no interesting folding happening, bail so that we don't create
440 // a constant that looks like it needs folding but really doesn't.
444 // Base case: Get a regular alignof expression.
445 Constant *C = ConstantExpr::getAlignOf(Ty);
446 C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
452 /// getFoldedOffsetOf - Return a ConstantExpr with type DestTy for offsetof
453 /// on Ty and FieldNo, with any known factors factored out. If Folded is false,
454 /// return null if no factoring was possible, to avoid endlessly
455 /// bouncing an unfoldable expression back into the top-level folder.
457 static Constant *getFoldedOffsetOf(const Type *Ty, Constant *FieldNo,
460 if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
461 Constant *N = ConstantExpr::getCast(CastInst::getCastOpcode(FieldNo, false,
464 Constant *E = getFoldedSizeOf(ATy->getElementType(), DestTy, true);
465 return ConstantExpr::getNUWMul(E, N);
467 if (const VectorType *VTy = dyn_cast<VectorType>(Ty)) {
468 Constant *N = ConstantExpr::getCast(CastInst::getCastOpcode(FieldNo, false,
471 Constant *E = getFoldedSizeOf(VTy->getElementType(), DestTy, true);
472 return ConstantExpr::getNUWMul(E, N);
474 if (const StructType *STy = dyn_cast<StructType>(Ty))
475 if (!STy->isPacked()) {
476 unsigned NumElems = STy->getNumElements();
477 // An empty struct has no members.
480 // Check for a struct with all members having the same size.
481 Constant *MemberSize =
482 getFoldedSizeOf(STy->getElementType(0), DestTy, true);
484 for (unsigned i = 1; i != NumElems; ++i)
486 getFoldedSizeOf(STy->getElementType(i), DestTy, true)) {
491 Constant *N = ConstantExpr::getCast(CastInst::getCastOpcode(FieldNo,
496 return ConstantExpr::getNUWMul(MemberSize, N);
500 // If there's no interesting folding happening, bail so that we don't create
501 // a constant that looks like it needs folding but really doesn't.
505 // Base case: Get a regular offsetof expression.
506 Constant *C = ConstantExpr::getOffsetOf(Ty, FieldNo);
507 C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
513 Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V,
514 const Type *DestTy) {
515 if (isa<UndefValue>(V)) {
516 // zext(undef) = 0, because the top bits will be zero.
517 // sext(undef) = 0, because the top bits will all be the same.
518 // [us]itofp(undef) = 0, because the result value is bounded.
519 if (opc == Instruction::ZExt || opc == Instruction::SExt ||
520 opc == Instruction::UIToFP || opc == Instruction::SIToFP)
521 return Constant::getNullValue(DestTy);
522 return UndefValue::get(DestTy);
524 // No compile-time operations on this type yet.
525 if (V->getType()->isPPC_FP128Ty() || DestTy->isPPC_FP128Ty())
528 // If the cast operand is a constant expression, there's a few things we can
529 // do to try to simplify it.
530 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
532 // Try hard to fold cast of cast because they are often eliminable.
533 if (unsigned newOpc = foldConstantCastPair(opc, CE, DestTy))
534 return ConstantExpr::getCast(newOpc, CE->getOperand(0), DestTy);
535 } else if (CE->getOpcode() == Instruction::GetElementPtr) {
536 // If all of the indexes in the GEP are null values, there is no pointer
537 // adjustment going on. We might as well cast the source pointer.
538 bool isAllNull = true;
539 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
540 if (!CE->getOperand(i)->isNullValue()) {
545 // This is casting one pointer type to another, always BitCast
546 return ConstantExpr::getPointerCast(CE->getOperand(0), DestTy);
550 // If the cast operand is a constant vector, perform the cast by
551 // operating on each element. In the cast of bitcasts, the element
552 // count may be mismatched; don't attempt to handle that here.
553 if (ConstantVector *CV = dyn_cast<ConstantVector>(V))
554 if (isa<VectorType>(DestTy) &&
555 cast<VectorType>(DestTy)->getNumElements() ==
556 CV->getType()->getNumElements()) {
557 std::vector<Constant*> res;
558 const VectorType *DestVecTy = cast<VectorType>(DestTy);
559 const Type *DstEltTy = DestVecTy->getElementType();
560 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
561 res.push_back(ConstantExpr::getCast(opc,
562 CV->getOperand(i), DstEltTy));
563 return ConstantVector::get(DestVecTy, res);
566 // We actually have to do a cast now. Perform the cast according to the
570 llvm_unreachable("Failed to cast constant expression");
571 case Instruction::FPTrunc:
572 case Instruction::FPExt:
573 if (ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
575 APFloat Val = FPC->getValueAPF();
576 Val.convert(DestTy->isFloatTy() ? APFloat::IEEEsingle :
577 DestTy->isDoubleTy() ? APFloat::IEEEdouble :
578 DestTy->isX86_FP80Ty() ? APFloat::x87DoubleExtended :
579 DestTy->isFP128Ty() ? APFloat::IEEEquad :
581 APFloat::rmNearestTiesToEven, &ignored);
582 return ConstantFP::get(V->getContext(), Val);
584 return 0; // Can't fold.
585 case Instruction::FPToUI:
586 case Instruction::FPToSI:
587 if (ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
588 const APFloat &V = FPC->getValueAPF();
591 uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
592 (void) V.convertToInteger(x, DestBitWidth, opc==Instruction::FPToSI,
593 APFloat::rmTowardZero, &ignored);
594 APInt Val(DestBitWidth, 2, x);
595 return ConstantInt::get(FPC->getContext(), Val);
597 return 0; // Can't fold.
598 case Instruction::IntToPtr: //always treated as unsigned
599 if (V->isNullValue()) // Is it an integral null value?
600 return ConstantPointerNull::get(cast<PointerType>(DestTy));
601 return 0; // Other pointer types cannot be casted
602 case Instruction::PtrToInt: // always treated as unsigned
603 // Is it a null pointer value?
604 if (V->isNullValue())
605 return ConstantInt::get(DestTy, 0);
606 // If this is a sizeof-like expression, pull out multiplications by
607 // known factors to expose them to subsequent folding. If it's an
608 // alignof-like expression, factor out known factors.
609 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
610 if (CE->getOpcode() == Instruction::GetElementPtr &&
611 CE->getOperand(0)->isNullValue()) {
613 cast<PointerType>(CE->getOperand(0)->getType())->getElementType();
614 if (CE->getNumOperands() == 2) {
615 // Handle a sizeof-like expression.
616 Constant *Idx = CE->getOperand(1);
617 bool isOne = isa<ConstantInt>(Idx) && cast<ConstantInt>(Idx)->isOne();
618 if (Constant *C = getFoldedSizeOf(Ty, DestTy, !isOne)) {
619 Idx = ConstantExpr::getCast(CastInst::getCastOpcode(Idx, true,
622 return ConstantExpr::getMul(C, Idx);
624 } else if (CE->getNumOperands() == 3 &&
625 CE->getOperand(1)->isNullValue()) {
626 // Handle an alignof-like expression.
627 if (const StructType *STy = dyn_cast<StructType>(Ty))
628 if (!STy->isPacked()) {
629 ConstantInt *CI = cast<ConstantInt>(CE->getOperand(2));
631 STy->getNumElements() == 2 &&
632 STy->getElementType(0)->isIntegerTy(1)) {
633 return getFoldedAlignOf(STy->getElementType(1), DestTy, false);
636 // Handle an offsetof-like expression.
637 if (isa<StructType>(Ty) || isa<ArrayType>(Ty) || isa<VectorType>(Ty)){
638 if (Constant *C = getFoldedOffsetOf(Ty, CE->getOperand(2),
644 // Other pointer types cannot be casted
646 case Instruction::UIToFP:
647 case Instruction::SIToFP:
648 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
649 APInt api = CI->getValue();
650 const uint64_t zero[] = {0, 0};
651 APFloat apf = APFloat(APInt(DestTy->getPrimitiveSizeInBits(),
653 (void)apf.convertFromAPInt(api,
654 opc==Instruction::SIToFP,
655 APFloat::rmNearestTiesToEven);
656 return ConstantFP::get(V->getContext(), apf);
659 case Instruction::ZExt:
660 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
661 uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
662 APInt Result(CI->getValue());
663 Result.zext(BitWidth);
664 return ConstantInt::get(V->getContext(), Result);
667 case Instruction::SExt:
668 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
669 uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
670 APInt Result(CI->getValue());
671 Result.sext(BitWidth);
672 return ConstantInt::get(V->getContext(), Result);
675 case Instruction::Trunc: {
676 uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
677 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
678 APInt Result(CI->getValue());
679 Result.trunc(DestBitWidth);
680 return ConstantInt::get(V->getContext(), Result);
683 // The input must be a constantexpr. See if we can simplify this based on
684 // the bytes we are demanding. Only do this if the source and dest are an
685 // even multiple of a byte.
686 if ((DestBitWidth & 7) == 0 &&
687 (cast<IntegerType>(V->getType())->getBitWidth() & 7) == 0)
688 if (Constant *Res = ExtractConstantBytes(V, 0, DestBitWidth / 8))
693 case Instruction::BitCast:
694 return FoldBitCast(V, DestTy);
698 Constant *llvm::ConstantFoldSelectInstruction(Constant *Cond,
699 Constant *V1, Constant *V2) {
700 if (ConstantInt *CB = dyn_cast<ConstantInt>(Cond))
701 return CB->getZExtValue() ? V1 : V2;
703 if (isa<UndefValue>(V1)) return V2;
704 if (isa<UndefValue>(V2)) return V1;
705 if (isa<UndefValue>(Cond)) return V1;
706 if (V1 == V2) return V1;
710 Constant *llvm::ConstantFoldExtractElementInstruction(Constant *Val,
712 if (isa<UndefValue>(Val)) // ee(undef, x) -> undef
713 return UndefValue::get(cast<VectorType>(Val->getType())->getElementType());
714 if (Val->isNullValue()) // ee(zero, x) -> zero
715 return Constant::getNullValue(
716 cast<VectorType>(Val->getType())->getElementType());
718 if (ConstantVector *CVal = dyn_cast<ConstantVector>(Val)) {
719 if (ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx)) {
720 return CVal->getOperand(CIdx->getZExtValue());
721 } else if (isa<UndefValue>(Idx)) {
722 // ee({w,x,y,z}, undef) -> w (an arbitrary value).
723 return CVal->getOperand(0);
729 Constant *llvm::ConstantFoldInsertElementInstruction(Constant *Val,
732 ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx);
734 APInt idxVal = CIdx->getValue();
735 if (isa<UndefValue>(Val)) {
736 // Insertion of scalar constant into vector undef
737 // Optimize away insertion of undef
738 if (isa<UndefValue>(Elt))
740 // Otherwise break the aggregate undef into multiple undefs and do
743 cast<VectorType>(Val->getType())->getNumElements();
744 std::vector<Constant*> Ops;
746 for (unsigned i = 0; i < numOps; ++i) {
748 (idxVal == i) ? Elt : UndefValue::get(Elt->getType());
751 return ConstantVector::get(Ops);
753 if (isa<ConstantAggregateZero>(Val)) {
754 // Insertion of scalar constant into vector aggregate zero
755 // Optimize away insertion of zero
756 if (Elt->isNullValue())
758 // Otherwise break the aggregate zero into multiple zeros and do
761 cast<VectorType>(Val->getType())->getNumElements();
762 std::vector<Constant*> Ops;
764 for (unsigned i = 0; i < numOps; ++i) {
766 (idxVal == i) ? Elt : Constant::getNullValue(Elt->getType());
769 return ConstantVector::get(Ops);
771 if (ConstantVector *CVal = dyn_cast<ConstantVector>(Val)) {
772 // Insertion of scalar constant into vector constant
773 std::vector<Constant*> Ops;
774 Ops.reserve(CVal->getNumOperands());
775 for (unsigned i = 0; i < CVal->getNumOperands(); ++i) {
777 (idxVal == i) ? Elt : cast<Constant>(CVal->getOperand(i));
780 return ConstantVector::get(Ops);
786 /// GetVectorElement - If C is a ConstantVector, ConstantAggregateZero or Undef
787 /// return the specified element value. Otherwise return null.
788 static Constant *GetVectorElement(Constant *C, unsigned EltNo) {
789 if (ConstantVector *CV = dyn_cast<ConstantVector>(C))
790 return CV->getOperand(EltNo);
792 const Type *EltTy = cast<VectorType>(C->getType())->getElementType();
793 if (isa<ConstantAggregateZero>(C))
794 return Constant::getNullValue(EltTy);
795 if (isa<UndefValue>(C))
796 return UndefValue::get(EltTy);
800 Constant *llvm::ConstantFoldShuffleVectorInstruction(Constant *V1,
803 // Undefined shuffle mask -> undefined value.
804 if (isa<UndefValue>(Mask)) return UndefValue::get(V1->getType());
806 unsigned MaskNumElts = cast<VectorType>(Mask->getType())->getNumElements();
807 unsigned SrcNumElts = cast<VectorType>(V1->getType())->getNumElements();
808 const Type *EltTy = cast<VectorType>(V1->getType())->getElementType();
810 // Loop over the shuffle mask, evaluating each element.
811 SmallVector<Constant*, 32> Result;
812 for (unsigned i = 0; i != MaskNumElts; ++i) {
813 Constant *InElt = GetVectorElement(Mask, i);
814 if (InElt == 0) return 0;
816 if (isa<UndefValue>(InElt))
817 InElt = UndefValue::get(EltTy);
818 else if (ConstantInt *CI = dyn_cast<ConstantInt>(InElt)) {
819 unsigned Elt = CI->getZExtValue();
820 if (Elt >= SrcNumElts*2)
821 InElt = UndefValue::get(EltTy);
822 else if (Elt >= SrcNumElts)
823 InElt = GetVectorElement(V2, Elt - SrcNumElts);
825 InElt = GetVectorElement(V1, Elt);
826 if (InElt == 0) return 0;
831 Result.push_back(InElt);
834 return ConstantVector::get(&Result[0], Result.size());
837 Constant *llvm::ConstantFoldExtractValueInstruction(Constant *Agg,
838 const unsigned *Idxs,
840 // Base case: no indices, so return the entire value.
844 if (isa<UndefValue>(Agg)) // ev(undef, x) -> undef
845 return UndefValue::get(ExtractValueInst::getIndexedType(Agg->getType(),
849 if (isa<ConstantAggregateZero>(Agg)) // ev(0, x) -> 0
851 Constant::getNullValue(ExtractValueInst::getIndexedType(Agg->getType(),
855 // Otherwise recurse.
856 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(Agg))
857 return ConstantFoldExtractValueInstruction(CS->getOperand(*Idxs),
860 if (ConstantArray *CA = dyn_cast<ConstantArray>(Agg))
861 return ConstantFoldExtractValueInstruction(CA->getOperand(*Idxs),
863 ConstantVector *CV = cast<ConstantVector>(Agg);
864 return ConstantFoldExtractValueInstruction(CV->getOperand(*Idxs),
868 Constant *llvm::ConstantFoldInsertValueInstruction(Constant *Agg,
870 const unsigned *Idxs,
872 // Base case: no indices, so replace the entire value.
876 if (isa<UndefValue>(Agg)) {
877 // Insertion of constant into aggregate undef
878 // Optimize away insertion of undef.
879 if (isa<UndefValue>(Val))
882 // Otherwise break the aggregate undef into multiple undefs and do
884 const CompositeType *AggTy = cast<CompositeType>(Agg->getType());
886 if (const ArrayType *AR = dyn_cast<ArrayType>(AggTy))
887 numOps = AR->getNumElements();
888 else if (isa<UnionType>(AggTy))
891 numOps = cast<StructType>(AggTy)->getNumElements();
893 std::vector<Constant*> Ops(numOps);
894 for (unsigned i = 0; i < numOps; ++i) {
895 const Type *MemberTy = AggTy->getTypeAtIndex(i);
898 ConstantFoldInsertValueInstruction(UndefValue::get(MemberTy),
899 Val, Idxs+1, NumIdx-1) :
900 UndefValue::get(MemberTy);
904 if (const StructType* ST = dyn_cast<StructType>(AggTy))
905 return ConstantStruct::get(ST->getContext(), Ops, ST->isPacked());
906 if (const UnionType* UT = dyn_cast<UnionType>(AggTy)) {
907 assert(Ops.size() == 1 && "Union can only contain a single value!");
908 return ConstantUnion::get(UT, Ops[0]);
910 return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
913 if (isa<ConstantAggregateZero>(Agg)) {
914 // Insertion of constant into aggregate zero
915 // Optimize away insertion of zero.
916 if (Val->isNullValue())
919 // Otherwise break the aggregate zero into multiple zeros and do
921 const CompositeType *AggTy = cast<CompositeType>(Agg->getType());
923 if (const ArrayType *AR = dyn_cast<ArrayType>(AggTy))
924 numOps = AR->getNumElements();
926 numOps = cast<StructType>(AggTy)->getNumElements();
928 std::vector<Constant*> Ops(numOps);
929 for (unsigned i = 0; i < numOps; ++i) {
930 const Type *MemberTy = AggTy->getTypeAtIndex(i);
933 ConstantFoldInsertValueInstruction(Constant::getNullValue(MemberTy),
934 Val, Idxs+1, NumIdx-1) :
935 Constant::getNullValue(MemberTy);
939 if (const StructType *ST = dyn_cast<StructType>(AggTy))
940 return ConstantStruct::get(ST->getContext(), Ops, ST->isPacked());
941 return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
944 if (isa<ConstantStruct>(Agg) || isa<ConstantArray>(Agg)) {
945 // Insertion of constant into aggregate constant.
946 std::vector<Constant*> Ops(Agg->getNumOperands());
947 for (unsigned i = 0; i < Agg->getNumOperands(); ++i) {
948 Constant *Op = cast<Constant>(Agg->getOperand(i));
950 Op = ConstantFoldInsertValueInstruction(Op, Val, Idxs+1, NumIdx-1);
954 if (const StructType* ST = dyn_cast<StructType>(Agg->getType()))
955 return ConstantStruct::get(ST->getContext(), Ops, ST->isPacked());
956 return ConstantArray::get(cast<ArrayType>(Agg->getType()), Ops);
963 Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
964 Constant *C1, Constant *C2) {
965 // No compile-time operations on this type yet.
966 if (C1->getType()->isPPC_FP128Ty())
969 // Handle UndefValue up front.
970 if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
972 case Instruction::Xor:
973 if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
974 // Handle undef ^ undef -> 0 special case. This is a common
976 return Constant::getNullValue(C1->getType());
978 case Instruction::Add:
979 case Instruction::Sub:
980 return UndefValue::get(C1->getType());
981 case Instruction::Mul:
982 case Instruction::And:
983 return Constant::getNullValue(C1->getType());
984 case Instruction::UDiv:
985 case Instruction::SDiv:
986 case Instruction::URem:
987 case Instruction::SRem:
988 if (!isa<UndefValue>(C2)) // undef / X -> 0
989 return Constant::getNullValue(C1->getType());
990 return C2; // X / undef -> undef
991 case Instruction::Or: // X | undef -> -1
992 if (const VectorType *PTy = dyn_cast<VectorType>(C1->getType()))
993 return Constant::getAllOnesValue(PTy);
994 return Constant::getAllOnesValue(C1->getType());
995 case Instruction::LShr:
996 if (isa<UndefValue>(C2) && isa<UndefValue>(C1))
997 return C1; // undef lshr undef -> undef
998 return Constant::getNullValue(C1->getType()); // X lshr undef -> 0
1000 case Instruction::AShr:
1001 if (!isa<UndefValue>(C2))
1002 return C1; // undef ashr X --> undef
1003 else if (isa<UndefValue>(C1))
1004 return C1; // undef ashr undef -> undef
1006 return C1; // X ashr undef --> X
1007 case Instruction::Shl:
1008 // undef << X -> 0 or X << undef -> 0
1009 return Constant::getNullValue(C1->getType());
1013 // Handle simplifications when the RHS is a constant int.
1014 if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
1016 case Instruction::Add:
1017 if (CI2->equalsInt(0)) return C1; // X + 0 == X
1019 case Instruction::Sub:
1020 if (CI2->equalsInt(0)) return C1; // X - 0 == X
1022 case Instruction::Mul:
1023 if (CI2->equalsInt(0)) return C2; // X * 0 == 0
1024 if (CI2->equalsInt(1))
1025 return C1; // X * 1 == X
1027 case Instruction::UDiv:
1028 case Instruction::SDiv:
1029 if (CI2->equalsInt(1))
1030 return C1; // X / 1 == X
1031 if (CI2->equalsInt(0))
1032 return UndefValue::get(CI2->getType()); // X / 0 == undef
1034 case Instruction::URem:
1035 case Instruction::SRem:
1036 if (CI2->equalsInt(1))
1037 return Constant::getNullValue(CI2->getType()); // X % 1 == 0
1038 if (CI2->equalsInt(0))
1039 return UndefValue::get(CI2->getType()); // X % 0 == undef
1041 case Instruction::And:
1042 if (CI2->isZero()) return C2; // X & 0 == 0
1043 if (CI2->isAllOnesValue())
1044 return C1; // X & -1 == X
1046 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1047 // (zext i32 to i64) & 4294967295 -> (zext i32 to i64)
1048 if (CE1->getOpcode() == Instruction::ZExt) {
1049 unsigned DstWidth = CI2->getType()->getBitWidth();
1051 CE1->getOperand(0)->getType()->getPrimitiveSizeInBits();
1052 APInt PossiblySetBits(APInt::getLowBitsSet(DstWidth, SrcWidth));
1053 if ((PossiblySetBits & CI2->getValue()) == PossiblySetBits)
1057 // If and'ing the address of a global with a constant, fold it.
1058 if (CE1->getOpcode() == Instruction::PtrToInt &&
1059 isa<GlobalValue>(CE1->getOperand(0))) {
1060 GlobalValue *GV = cast<GlobalValue>(CE1->getOperand(0));
1062 // Functions are at least 4-byte aligned.
1063 unsigned GVAlign = GV->getAlignment();
1064 if (isa<Function>(GV))
1065 GVAlign = std::max(GVAlign, 4U);
1068 unsigned DstWidth = CI2->getType()->getBitWidth();
1069 unsigned SrcWidth = std::min(DstWidth, Log2_32(GVAlign));
1070 APInt BitsNotSet(APInt::getLowBitsSet(DstWidth, SrcWidth));
1072 // If checking bits we know are clear, return zero.
1073 if ((CI2->getValue() & BitsNotSet) == CI2->getValue())
1074 return Constant::getNullValue(CI2->getType());
1079 case Instruction::Or:
1080 if (CI2->equalsInt(0)) return C1; // X | 0 == X
1081 if (CI2->isAllOnesValue())
1082 return C2; // X | -1 == -1
1084 case Instruction::Xor:
1085 if (CI2->equalsInt(0)) return C1; // X ^ 0 == X
1087 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1088 switch (CE1->getOpcode()) {
1090 case Instruction::ICmp:
1091 case Instruction::FCmp:
1092 // cmp pred ^ true -> cmp !pred
1093 assert(CI2->equalsInt(1));
1094 CmpInst::Predicate pred = (CmpInst::Predicate)CE1->getPredicate();
1095 pred = CmpInst::getInversePredicate(pred);
1096 return ConstantExpr::getCompare(pred, CE1->getOperand(0),
1097 CE1->getOperand(1));
1101 case Instruction::AShr:
1102 // ashr (zext C to Ty), C2 -> lshr (zext C, CSA), C2
1103 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1))
1104 if (CE1->getOpcode() == Instruction::ZExt) // Top bits known zero.
1105 return ConstantExpr::getLShr(C1, C2);
1110 // At this point we know neither constant is an UndefValue.
1111 if (ConstantInt *CI1 = dyn_cast<ConstantInt>(C1)) {
1112 if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
1113 using namespace APIntOps;
1114 const APInt &C1V = CI1->getValue();
1115 const APInt &C2V = CI2->getValue();
1119 case Instruction::Add:
1120 return ConstantInt::get(CI1->getContext(), C1V + C2V);
1121 case Instruction::Sub:
1122 return ConstantInt::get(CI1->getContext(), C1V - C2V);
1123 case Instruction::Mul:
1124 return ConstantInt::get(CI1->getContext(), C1V * C2V);
1125 case Instruction::UDiv:
1126 assert(!CI2->isNullValue() && "Div by zero handled above");
1127 return ConstantInt::get(CI1->getContext(), C1V.udiv(C2V));
1128 case Instruction::SDiv:
1129 assert(!CI2->isNullValue() && "Div by zero handled above");
1130 if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
1131 return UndefValue::get(CI1->getType()); // MIN_INT / -1 -> undef
1132 return ConstantInt::get(CI1->getContext(), C1V.sdiv(C2V));
1133 case Instruction::URem:
1134 assert(!CI2->isNullValue() && "Div by zero handled above");
1135 return ConstantInt::get(CI1->getContext(), C1V.urem(C2V));
1136 case Instruction::SRem:
1137 assert(!CI2->isNullValue() && "Div by zero handled above");
1138 if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
1139 return UndefValue::get(CI1->getType()); // MIN_INT % -1 -> undef
1140 return ConstantInt::get(CI1->getContext(), C1V.srem(C2V));
1141 case Instruction::And:
1142 return ConstantInt::get(CI1->getContext(), C1V & C2V);
1143 case Instruction::Or:
1144 return ConstantInt::get(CI1->getContext(), C1V | C2V);
1145 case Instruction::Xor:
1146 return ConstantInt::get(CI1->getContext(), C1V ^ C2V);
1147 case Instruction::Shl: {
1148 uint32_t shiftAmt = C2V.getZExtValue();
1149 if (shiftAmt < C1V.getBitWidth())
1150 return ConstantInt::get(CI1->getContext(), C1V.shl(shiftAmt));
1152 return UndefValue::get(C1->getType()); // too big shift is undef
1154 case Instruction::LShr: {
1155 uint32_t shiftAmt = C2V.getZExtValue();
1156 if (shiftAmt < C1V.getBitWidth())
1157 return ConstantInt::get(CI1->getContext(), C1V.lshr(shiftAmt));
1159 return UndefValue::get(C1->getType()); // too big shift is undef
1161 case Instruction::AShr: {
1162 uint32_t shiftAmt = C2V.getZExtValue();
1163 if (shiftAmt < C1V.getBitWidth())
1164 return ConstantInt::get(CI1->getContext(), C1V.ashr(shiftAmt));
1166 return UndefValue::get(C1->getType()); // too big shift is undef
1172 case Instruction::SDiv:
1173 case Instruction::UDiv:
1174 case Instruction::URem:
1175 case Instruction::SRem:
1176 case Instruction::LShr:
1177 case Instruction::AShr:
1178 case Instruction::Shl:
1179 if (CI1->equalsInt(0)) return C1;
1184 } else if (ConstantFP *CFP1 = dyn_cast<ConstantFP>(C1)) {
1185 if (ConstantFP *CFP2 = dyn_cast<ConstantFP>(C2)) {
1186 APFloat C1V = CFP1->getValueAPF();
1187 APFloat C2V = CFP2->getValueAPF();
1188 APFloat C3V = C1V; // copy for modification
1192 case Instruction::FAdd:
1193 (void)C3V.add(C2V, APFloat::rmNearestTiesToEven);
1194 return ConstantFP::get(C1->getContext(), C3V);
1195 case Instruction::FSub:
1196 (void)C3V.subtract(C2V, APFloat::rmNearestTiesToEven);
1197 return ConstantFP::get(C1->getContext(), C3V);
1198 case Instruction::FMul:
1199 (void)C3V.multiply(C2V, APFloat::rmNearestTiesToEven);
1200 return ConstantFP::get(C1->getContext(), C3V);
1201 case Instruction::FDiv:
1202 (void)C3V.divide(C2V, APFloat::rmNearestTiesToEven);
1203 return ConstantFP::get(C1->getContext(), C3V);
1204 case Instruction::FRem:
1205 (void)C3V.mod(C2V, APFloat::rmNearestTiesToEven);
1206 return ConstantFP::get(C1->getContext(), C3V);
1209 } else if (const VectorType *VTy = dyn_cast<VectorType>(C1->getType())) {
1210 ConstantVector *CP1 = dyn_cast<ConstantVector>(C1);
1211 ConstantVector *CP2 = dyn_cast<ConstantVector>(C2);
1212 if ((CP1 != NULL || isa<ConstantAggregateZero>(C1)) &&
1213 (CP2 != NULL || isa<ConstantAggregateZero>(C2))) {
1214 std::vector<Constant*> Res;
1215 const Type* EltTy = VTy->getElementType();
1221 case Instruction::Add:
1222 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1223 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1224 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1225 Res.push_back(ConstantExpr::getAdd(C1, C2));
1227 return ConstantVector::get(Res);
1228 case Instruction::FAdd:
1229 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1230 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1231 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1232 Res.push_back(ConstantExpr::getFAdd(C1, C2));
1234 return ConstantVector::get(Res);
1235 case Instruction::Sub:
1236 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1237 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1238 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1239 Res.push_back(ConstantExpr::getSub(C1, C2));
1241 return ConstantVector::get(Res);
1242 case Instruction::FSub:
1243 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1244 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1245 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1246 Res.push_back(ConstantExpr::getFSub(C1, C2));
1248 return ConstantVector::get(Res);
1249 case Instruction::Mul:
1250 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1251 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1252 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1253 Res.push_back(ConstantExpr::getMul(C1, C2));
1255 return ConstantVector::get(Res);
1256 case Instruction::FMul:
1257 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1258 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1259 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1260 Res.push_back(ConstantExpr::getFMul(C1, C2));
1262 return ConstantVector::get(Res);
1263 case Instruction::UDiv:
1264 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1265 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1266 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1267 Res.push_back(ConstantExpr::getUDiv(C1, C2));
1269 return ConstantVector::get(Res);
1270 case Instruction::SDiv:
1271 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1272 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1273 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1274 Res.push_back(ConstantExpr::getSDiv(C1, C2));
1276 return ConstantVector::get(Res);
1277 case Instruction::FDiv:
1278 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1279 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1280 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1281 Res.push_back(ConstantExpr::getFDiv(C1, C2));
1283 return ConstantVector::get(Res);
1284 case Instruction::URem:
1285 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1286 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1287 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1288 Res.push_back(ConstantExpr::getURem(C1, C2));
1290 return ConstantVector::get(Res);
1291 case Instruction::SRem:
1292 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1293 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1294 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1295 Res.push_back(ConstantExpr::getSRem(C1, C2));
1297 return ConstantVector::get(Res);
1298 case Instruction::FRem:
1299 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1300 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1301 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1302 Res.push_back(ConstantExpr::getFRem(C1, C2));
1304 return ConstantVector::get(Res);
1305 case Instruction::And:
1306 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1307 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1308 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1309 Res.push_back(ConstantExpr::getAnd(C1, C2));
1311 return ConstantVector::get(Res);
1312 case Instruction::Or:
1313 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1314 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1315 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1316 Res.push_back(ConstantExpr::getOr(C1, C2));
1318 return ConstantVector::get(Res);
1319 case Instruction::Xor:
1320 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1321 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1322 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1323 Res.push_back(ConstantExpr::getXor(C1, C2));
1325 return ConstantVector::get(Res);
1326 case Instruction::LShr:
1327 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1328 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1329 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1330 Res.push_back(ConstantExpr::getLShr(C1, C2));
1332 return ConstantVector::get(Res);
1333 case Instruction::AShr:
1334 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1335 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1336 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1337 Res.push_back(ConstantExpr::getAShr(C1, C2));
1339 return ConstantVector::get(Res);
1340 case Instruction::Shl:
1341 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1342 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1343 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1344 Res.push_back(ConstantExpr::getShl(C1, C2));
1346 return ConstantVector::get(Res);
1351 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1352 // There are many possible foldings we could do here. We should probably
1353 // at least fold add of a pointer with an integer into the appropriate
1354 // getelementptr. This will improve alias analysis a bit.
1356 // Given ((a + b) + c), if (b + c) folds to something interesting, return
1358 if (Instruction::isAssociative(Opcode, C1->getType()) &&
1359 CE1->getOpcode() == Opcode) {
1360 Constant *T = ConstantExpr::get(Opcode, CE1->getOperand(1), C2);
1361 if (!isa<ConstantExpr>(T) || cast<ConstantExpr>(T)->getOpcode() != Opcode)
1362 return ConstantExpr::get(Opcode, CE1->getOperand(0), T);
1364 } else if (isa<ConstantExpr>(C2)) {
1365 // If C2 is a constant expr and C1 isn't, flop them around and fold the
1366 // other way if possible.
1368 case Instruction::Add:
1369 case Instruction::FAdd:
1370 case Instruction::Mul:
1371 case Instruction::FMul:
1372 case Instruction::And:
1373 case Instruction::Or:
1374 case Instruction::Xor:
1375 // No change of opcode required.
1376 return ConstantFoldBinaryInstruction(Opcode, C2, C1);
1378 case Instruction::Shl:
1379 case Instruction::LShr:
1380 case Instruction::AShr:
1381 case Instruction::Sub:
1382 case Instruction::FSub:
1383 case Instruction::SDiv:
1384 case Instruction::UDiv:
1385 case Instruction::FDiv:
1386 case Instruction::URem:
1387 case Instruction::SRem:
1388 case Instruction::FRem:
1389 default: // These instructions cannot be flopped around.
1394 // i1 can be simplified in many cases.
1395 if (C1->getType()->isIntegerTy(1)) {
1397 case Instruction::Add:
1398 case Instruction::Sub:
1399 return ConstantExpr::getXor(C1, C2);
1400 case Instruction::Mul:
1401 return ConstantExpr::getAnd(C1, C2);
1402 case Instruction::Shl:
1403 case Instruction::LShr:
1404 case Instruction::AShr:
1405 // We can assume that C2 == 0. If it were one the result would be
1406 // undefined because the shift value is as large as the bitwidth.
1408 case Instruction::SDiv:
1409 case Instruction::UDiv:
1410 // We can assume that C2 == 1. If it were zero the result would be
1411 // undefined through division by zero.
1413 case Instruction::URem:
1414 case Instruction::SRem:
1415 // We can assume that C2 == 1. If it were zero the result would be
1416 // undefined through division by zero.
1417 return ConstantInt::getFalse(C1->getContext());
1423 // We don't know how to fold this.
1427 /// isZeroSizedType - This type is zero sized if its an array or structure of
1428 /// zero sized types. The only leaf zero sized type is an empty structure.
1429 static bool isMaybeZeroSizedType(const Type *Ty) {
1430 if (isa<OpaqueType>(Ty)) return true; // Can't say.
1431 if (const StructType *STy = dyn_cast<StructType>(Ty)) {
1433 // If all of elements have zero size, this does too.
1434 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
1435 if (!isMaybeZeroSizedType(STy->getElementType(i))) return false;
1438 } else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
1439 return isMaybeZeroSizedType(ATy->getElementType());
1444 /// IdxCompare - Compare the two constants as though they were getelementptr
1445 /// indices. This allows coersion of the types to be the same thing.
1447 /// If the two constants are the "same" (after coersion), return 0. If the
1448 /// first is less than the second, return -1, if the second is less than the
1449 /// first, return 1. If the constants are not integral, return -2.
1451 static int IdxCompare(Constant *C1, Constant *C2, const Type *ElTy) {
1452 if (C1 == C2) return 0;
1454 // Ok, we found a different index. If they are not ConstantInt, we can't do
1455 // anything with them.
1456 if (!isa<ConstantInt>(C1) || !isa<ConstantInt>(C2))
1457 return -2; // don't know!
1459 // Ok, we have two differing integer indices. Sign extend them to be the same
1460 // type. Long is always big enough, so we use it.
1461 if (!C1->getType()->isIntegerTy(64))
1462 C1 = ConstantExpr::getSExt(C1, Type::getInt64Ty(C1->getContext()));
1464 if (!C2->getType()->isIntegerTy(64))
1465 C2 = ConstantExpr::getSExt(C2, Type::getInt64Ty(C1->getContext()));
1467 if (C1 == C2) return 0; // They are equal
1469 // If the type being indexed over is really just a zero sized type, there is
1470 // no pointer difference being made here.
1471 if (isMaybeZeroSizedType(ElTy))
1472 return -2; // dunno.
1474 // If they are really different, now that they are the same type, then we
1475 // found a difference!
1476 if (cast<ConstantInt>(C1)->getSExtValue() <
1477 cast<ConstantInt>(C2)->getSExtValue())
1483 /// evaluateFCmpRelation - This function determines if there is anything we can
1484 /// decide about the two constants provided. This doesn't need to handle simple
1485 /// things like ConstantFP comparisons, but should instead handle ConstantExprs.
1486 /// If we can determine that the two constants have a particular relation to
1487 /// each other, we should return the corresponding FCmpInst predicate,
1488 /// otherwise return FCmpInst::BAD_FCMP_PREDICATE. This is used below in
1489 /// ConstantFoldCompareInstruction.
1491 /// To simplify this code we canonicalize the relation so that the first
1492 /// operand is always the most "complex" of the two. We consider ConstantFP
1493 /// to be the simplest, and ConstantExprs to be the most complex.
1494 static FCmpInst::Predicate evaluateFCmpRelation(Constant *V1, Constant *V2) {
1495 assert(V1->getType() == V2->getType() &&
1496 "Cannot compare values of different types!");
1498 // No compile-time operations on this type yet.
1499 if (V1->getType()->isPPC_FP128Ty())
1500 return FCmpInst::BAD_FCMP_PREDICATE;
1502 // Handle degenerate case quickly
1503 if (V1 == V2) return FCmpInst::FCMP_OEQ;
1505 if (!isa<ConstantExpr>(V1)) {
1506 if (!isa<ConstantExpr>(V2)) {
1507 // We distilled thisUse the standard constant folder for a few cases
1509 R = dyn_cast<ConstantInt>(
1510 ConstantExpr::getFCmp(FCmpInst::FCMP_OEQ, V1, V2));
1511 if (R && !R->isZero())
1512 return FCmpInst::FCMP_OEQ;
1513 R = dyn_cast<ConstantInt>(
1514 ConstantExpr::getFCmp(FCmpInst::FCMP_OLT, V1, V2));
1515 if (R && !R->isZero())
1516 return FCmpInst::FCMP_OLT;
1517 R = dyn_cast<ConstantInt>(
1518 ConstantExpr::getFCmp(FCmpInst::FCMP_OGT, V1, V2));
1519 if (R && !R->isZero())
1520 return FCmpInst::FCMP_OGT;
1522 // Nothing more we can do
1523 return FCmpInst::BAD_FCMP_PREDICATE;
1526 // If the first operand is simple and second is ConstantExpr, swap operands.
1527 FCmpInst::Predicate SwappedRelation = evaluateFCmpRelation(V2, V1);
1528 if (SwappedRelation != FCmpInst::BAD_FCMP_PREDICATE)
1529 return FCmpInst::getSwappedPredicate(SwappedRelation);
1531 // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1532 // constantexpr or a simple constant.
1533 ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1534 switch (CE1->getOpcode()) {
1535 case Instruction::FPTrunc:
1536 case Instruction::FPExt:
1537 case Instruction::UIToFP:
1538 case Instruction::SIToFP:
1539 // We might be able to do something with these but we don't right now.
1545 // There are MANY other foldings that we could perform here. They will
1546 // probably be added on demand, as they seem needed.
1547 return FCmpInst::BAD_FCMP_PREDICATE;
1550 /// evaluateICmpRelation - This function determines if there is anything we can
1551 /// decide about the two constants provided. This doesn't need to handle simple
1552 /// things like integer comparisons, but should instead handle ConstantExprs
1553 /// and GlobalValues. If we can determine that the two constants have a
1554 /// particular relation to each other, we should return the corresponding ICmp
1555 /// predicate, otherwise return ICmpInst::BAD_ICMP_PREDICATE.
1557 /// To simplify this code we canonicalize the relation so that the first
1558 /// operand is always the most "complex" of the two. We consider simple
1559 /// constants (like ConstantInt) to be the simplest, followed by
1560 /// GlobalValues, followed by ConstantExpr's (the most complex).
1562 static ICmpInst::Predicate evaluateICmpRelation(Constant *V1, Constant *V2,
1564 assert(V1->getType() == V2->getType() &&
1565 "Cannot compare different types of values!");
1566 if (V1 == V2) return ICmpInst::ICMP_EQ;
1568 if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1) &&
1569 !isa<BlockAddress>(V1)) {
1570 if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2) &&
1571 !isa<BlockAddress>(V2)) {
1572 // We distilled this down to a simple case, use the standard constant
1575 ICmpInst::Predicate pred = ICmpInst::ICMP_EQ;
1576 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1577 if (R && !R->isZero())
1579 pred = isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1580 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1581 if (R && !R->isZero())
1583 pred = isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1584 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1585 if (R && !R->isZero())
1588 // If we couldn't figure it out, bail.
1589 return ICmpInst::BAD_ICMP_PREDICATE;
1592 // If the first operand is simple, swap operands.
1593 ICmpInst::Predicate SwappedRelation =
1594 evaluateICmpRelation(V2, V1, isSigned);
1595 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1596 return ICmpInst::getSwappedPredicate(SwappedRelation);
1598 } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1)) {
1599 if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1600 ICmpInst::Predicate SwappedRelation =
1601 evaluateICmpRelation(V2, V1, isSigned);
1602 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1603 return ICmpInst::getSwappedPredicate(SwappedRelation);
1604 return ICmpInst::BAD_ICMP_PREDICATE;
1607 // Now we know that the RHS is a GlobalValue, BlockAddress or simple
1608 // constant (which, since the types must match, means that it's a
1609 // ConstantPointerNull).
1610 if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
1611 // Don't try to decide equality of aliases.
1612 if (!isa<GlobalAlias>(GV) && !isa<GlobalAlias>(GV2))
1613 if (!GV->hasExternalWeakLinkage() || !GV2->hasExternalWeakLinkage())
1614 return ICmpInst::ICMP_NE;
1615 } else if (isa<BlockAddress>(V2)) {
1616 return ICmpInst::ICMP_NE; // Globals never equal labels.
1618 assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!");
1619 // GlobalVals can never be null unless they have external weak linkage.
1620 // We don't try to evaluate aliases here.
1621 if (!GV->hasExternalWeakLinkage() && !isa<GlobalAlias>(GV))
1622 return ICmpInst::ICMP_NE;
1624 } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(V1)) {
1625 if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1626 ICmpInst::Predicate SwappedRelation =
1627 evaluateICmpRelation(V2, V1, isSigned);
1628 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1629 return ICmpInst::getSwappedPredicate(SwappedRelation);
1630 return ICmpInst::BAD_ICMP_PREDICATE;
1633 // Now we know that the RHS is a GlobalValue, BlockAddress or simple
1634 // constant (which, since the types must match, means that it is a
1635 // ConstantPointerNull).
1636 if (const BlockAddress *BA2 = dyn_cast<BlockAddress>(V2)) {
1637 // Block address in another function can't equal this one, but block
1638 // addresses in the current function might be the same if blocks are
1640 if (BA2->getFunction() != BA->getFunction())
1641 return ICmpInst::ICMP_NE;
1643 // Block addresses aren't null, don't equal the address of globals.
1644 assert((isa<ConstantPointerNull>(V2) || isa<GlobalValue>(V2)) &&
1645 "Canonicalization guarantee!");
1646 return ICmpInst::ICMP_NE;
1649 // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1650 // constantexpr, a global, block address, or a simple constant.
1651 ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1652 Constant *CE1Op0 = CE1->getOperand(0);
1654 switch (CE1->getOpcode()) {
1655 case Instruction::Trunc:
1656 case Instruction::FPTrunc:
1657 case Instruction::FPExt:
1658 case Instruction::FPToUI:
1659 case Instruction::FPToSI:
1660 break; // We can't evaluate floating point casts or truncations.
1662 case Instruction::UIToFP:
1663 case Instruction::SIToFP:
1664 case Instruction::BitCast:
1665 case Instruction::ZExt:
1666 case Instruction::SExt:
1667 // If the cast is not actually changing bits, and the second operand is a
1668 // null pointer, do the comparison with the pre-casted value.
1669 if (V2->isNullValue() &&
1670 (isa<PointerType>(CE1->getType()) || CE1->getType()->isIntegerTy())) {
1671 if (CE1->getOpcode() == Instruction::ZExt) isSigned = false;
1672 if (CE1->getOpcode() == Instruction::SExt) isSigned = true;
1673 return evaluateICmpRelation(CE1Op0,
1674 Constant::getNullValue(CE1Op0->getType()),
1679 case Instruction::GetElementPtr:
1680 // Ok, since this is a getelementptr, we know that the constant has a
1681 // pointer type. Check the various cases.
1682 if (isa<ConstantPointerNull>(V2)) {
1683 // If we are comparing a GEP to a null pointer, check to see if the base
1684 // of the GEP equals the null pointer.
1685 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1686 if (GV->hasExternalWeakLinkage())
1687 // Weak linkage GVals could be zero or not. We're comparing that
1688 // to null pointer so its greater-or-equal
1689 return isSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE;
1691 // If its not weak linkage, the GVal must have a non-zero address
1692 // so the result is greater-than
1693 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1694 } else if (isa<ConstantPointerNull>(CE1Op0)) {
1695 // If we are indexing from a null pointer, check to see if we have any
1696 // non-zero indices.
1697 for (unsigned i = 1, e = CE1->getNumOperands(); i != e; ++i)
1698 if (!CE1->getOperand(i)->isNullValue())
1699 // Offsetting from null, must not be equal.
1700 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1701 // Only zero indexes from null, must still be zero.
1702 return ICmpInst::ICMP_EQ;
1704 // Otherwise, we can't really say if the first operand is null or not.
1705 } else if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
1706 if (isa<ConstantPointerNull>(CE1Op0)) {
1707 if (GV2->hasExternalWeakLinkage())
1708 // Weak linkage GVals could be zero or not. We're comparing it to
1709 // a null pointer, so its less-or-equal
1710 return isSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE;
1712 // If its not weak linkage, the GVal must have a non-zero address
1713 // so the result is less-than
1714 return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1715 } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1717 // If this is a getelementptr of the same global, then it must be
1718 // different. Because the types must match, the getelementptr could
1719 // only have at most one index, and because we fold getelementptr's
1720 // with a single zero index, it must be nonzero.
1721 assert(CE1->getNumOperands() == 2 &&
1722 !CE1->getOperand(1)->isNullValue() &&
1723 "Suprising getelementptr!");
1724 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1726 // If they are different globals, we don't know what the value is,
1727 // but they can't be equal.
1728 return ICmpInst::ICMP_NE;
1732 ConstantExpr *CE2 = cast<ConstantExpr>(V2);
1733 Constant *CE2Op0 = CE2->getOperand(0);
1735 // There are MANY other foldings that we could perform here. They will
1736 // probably be added on demand, as they seem needed.
1737 switch (CE2->getOpcode()) {
1739 case Instruction::GetElementPtr:
1740 // By far the most common case to handle is when the base pointers are
1741 // obviously to the same or different globals.
1742 if (isa<GlobalValue>(CE1Op0) && isa<GlobalValue>(CE2Op0)) {
1743 if (CE1Op0 != CE2Op0) // Don't know relative ordering, but not equal
1744 return ICmpInst::ICMP_NE;
1745 // Ok, we know that both getelementptr instructions are based on the
1746 // same global. From this, we can precisely determine the relative
1747 // ordering of the resultant pointers.
1750 // The logic below assumes that the result of the comparison
1751 // can be determined by finding the first index that differs.
1752 // This doesn't work if there is over-indexing in any
1753 // subsequent indices, so check for that case first.
1754 if (!CE1->isGEPWithNoNotionalOverIndexing() ||
1755 !CE2->isGEPWithNoNotionalOverIndexing())
1756 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1758 // Compare all of the operands the GEP's have in common.
1759 gep_type_iterator GTI = gep_type_begin(CE1);
1760 for (;i != CE1->getNumOperands() && i != CE2->getNumOperands();
1762 switch (IdxCompare(CE1->getOperand(i),
1763 CE2->getOperand(i), GTI.getIndexedType())) {
1764 case -1: return isSigned ? ICmpInst::ICMP_SLT:ICmpInst::ICMP_ULT;
1765 case 1: return isSigned ? ICmpInst::ICMP_SGT:ICmpInst::ICMP_UGT;
1766 case -2: return ICmpInst::BAD_ICMP_PREDICATE;
1769 // Ok, we ran out of things they have in common. If any leftovers
1770 // are non-zero then we have a difference, otherwise we are equal.
1771 for (; i < CE1->getNumOperands(); ++i)
1772 if (!CE1->getOperand(i)->isNullValue()) {
1773 if (isa<ConstantInt>(CE1->getOperand(i)))
1774 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1776 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1779 for (; i < CE2->getNumOperands(); ++i)
1780 if (!CE2->getOperand(i)->isNullValue()) {
1781 if (isa<ConstantInt>(CE2->getOperand(i)))
1782 return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1784 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1786 return ICmpInst::ICMP_EQ;
1795 return ICmpInst::BAD_ICMP_PREDICATE;
1798 Constant *llvm::ConstantFoldCompareInstruction(unsigned short pred,
1799 Constant *C1, Constant *C2) {
1800 const Type *ResultTy;
1801 if (const VectorType *VT = dyn_cast<VectorType>(C1->getType()))
1802 ResultTy = VectorType::get(Type::getInt1Ty(C1->getContext()),
1803 VT->getNumElements());
1805 ResultTy = Type::getInt1Ty(C1->getContext());
1807 // Fold FCMP_FALSE/FCMP_TRUE unconditionally.
1808 if (pred == FCmpInst::FCMP_FALSE)
1809 return Constant::getNullValue(ResultTy);
1811 if (pred == FCmpInst::FCMP_TRUE)
1812 return Constant::getAllOnesValue(ResultTy);
1814 // Handle some degenerate cases first
1815 if (isa<UndefValue>(C1) || isa<UndefValue>(C2))
1816 return UndefValue::get(ResultTy);
1818 // No compile-time operations on this type yet.
1819 if (C1->getType()->isPPC_FP128Ty())
1822 // icmp eq/ne(null,GV) -> false/true
1823 if (C1->isNullValue()) {
1824 if (const GlobalValue *GV = dyn_cast<GlobalValue>(C2))
1825 // Don't try to evaluate aliases. External weak GV can be null.
1826 if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
1827 if (pred == ICmpInst::ICMP_EQ)
1828 return ConstantInt::getFalse(C1->getContext());
1829 else if (pred == ICmpInst::ICMP_NE)
1830 return ConstantInt::getTrue(C1->getContext());
1832 // icmp eq/ne(GV,null) -> false/true
1833 } else if (C2->isNullValue()) {
1834 if (const GlobalValue *GV = dyn_cast<GlobalValue>(C1))
1835 // Don't try to evaluate aliases. External weak GV can be null.
1836 if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
1837 if (pred == ICmpInst::ICMP_EQ)
1838 return ConstantInt::getFalse(C1->getContext());
1839 else if (pred == ICmpInst::ICMP_NE)
1840 return ConstantInt::getTrue(C1->getContext());
1844 // If the comparison is a comparison between two i1's, simplify it.
1845 if (C1->getType()->isIntegerTy(1)) {
1847 case ICmpInst::ICMP_EQ:
1848 if (isa<ConstantInt>(C2))
1849 return ConstantExpr::getXor(C1, ConstantExpr::getNot(C2));
1850 return ConstantExpr::getXor(ConstantExpr::getNot(C1), C2);
1851 case ICmpInst::ICMP_NE:
1852 return ConstantExpr::getXor(C1, C2);
1858 if (isa<ConstantInt>(C1) && isa<ConstantInt>(C2)) {
1859 APInt V1 = cast<ConstantInt>(C1)->getValue();
1860 APInt V2 = cast<ConstantInt>(C2)->getValue();
1862 default: llvm_unreachable("Invalid ICmp Predicate"); return 0;
1863 case ICmpInst::ICMP_EQ: return ConstantInt::get(ResultTy, V1 == V2);
1864 case ICmpInst::ICMP_NE: return ConstantInt::get(ResultTy, V1 != V2);
1865 case ICmpInst::ICMP_SLT: return ConstantInt::get(ResultTy, V1.slt(V2));
1866 case ICmpInst::ICMP_SGT: return ConstantInt::get(ResultTy, V1.sgt(V2));
1867 case ICmpInst::ICMP_SLE: return ConstantInt::get(ResultTy, V1.sle(V2));
1868 case ICmpInst::ICMP_SGE: return ConstantInt::get(ResultTy, V1.sge(V2));
1869 case ICmpInst::ICMP_ULT: return ConstantInt::get(ResultTy, V1.ult(V2));
1870 case ICmpInst::ICMP_UGT: return ConstantInt::get(ResultTy, V1.ugt(V2));
1871 case ICmpInst::ICMP_ULE: return ConstantInt::get(ResultTy, V1.ule(V2));
1872 case ICmpInst::ICMP_UGE: return ConstantInt::get(ResultTy, V1.uge(V2));
1874 } else if (isa<ConstantFP>(C1) && isa<ConstantFP>(C2)) {
1875 APFloat C1V = cast<ConstantFP>(C1)->getValueAPF();
1876 APFloat C2V = cast<ConstantFP>(C2)->getValueAPF();
1877 APFloat::cmpResult R = C1V.compare(C2V);
1879 default: llvm_unreachable("Invalid FCmp Predicate"); return 0;
1880 case FCmpInst::FCMP_FALSE: return Constant::getNullValue(ResultTy);
1881 case FCmpInst::FCMP_TRUE: return Constant::getAllOnesValue(ResultTy);
1882 case FCmpInst::FCMP_UNO:
1883 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered);
1884 case FCmpInst::FCMP_ORD:
1885 return ConstantInt::get(ResultTy, R!=APFloat::cmpUnordered);
1886 case FCmpInst::FCMP_UEQ:
1887 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1888 R==APFloat::cmpEqual);
1889 case FCmpInst::FCMP_OEQ:
1890 return ConstantInt::get(ResultTy, R==APFloat::cmpEqual);
1891 case FCmpInst::FCMP_UNE:
1892 return ConstantInt::get(ResultTy, R!=APFloat::cmpEqual);
1893 case FCmpInst::FCMP_ONE:
1894 return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
1895 R==APFloat::cmpGreaterThan);
1896 case FCmpInst::FCMP_ULT:
1897 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1898 R==APFloat::cmpLessThan);
1899 case FCmpInst::FCMP_OLT:
1900 return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan);
1901 case FCmpInst::FCMP_UGT:
1902 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1903 R==APFloat::cmpGreaterThan);
1904 case FCmpInst::FCMP_OGT:
1905 return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan);
1906 case FCmpInst::FCMP_ULE:
1907 return ConstantInt::get(ResultTy, R!=APFloat::cmpGreaterThan);
1908 case FCmpInst::FCMP_OLE:
1909 return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
1910 R==APFloat::cmpEqual);
1911 case FCmpInst::FCMP_UGE:
1912 return ConstantInt::get(ResultTy, R!=APFloat::cmpLessThan);
1913 case FCmpInst::FCMP_OGE:
1914 return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan ||
1915 R==APFloat::cmpEqual);
1917 } else if (isa<VectorType>(C1->getType())) {
1918 SmallVector<Constant*, 16> C1Elts, C2Elts;
1919 C1->getVectorElements(C1Elts);
1920 C2->getVectorElements(C2Elts);
1921 if (C1Elts.empty() || C2Elts.empty())
1924 // If we can constant fold the comparison of each element, constant fold
1925 // the whole vector comparison.
1926 SmallVector<Constant*, 4> ResElts;
1927 for (unsigned i = 0, e = C1Elts.size(); i != e; ++i) {
1928 // Compare the elements, producing an i1 result or constant expr.
1929 ResElts.push_back(ConstantExpr::getCompare(pred, C1Elts[i], C2Elts[i]));
1931 return ConstantVector::get(&ResElts[0], ResElts.size());
1934 if (C1->getType()->isFloatingPointTy()) {
1935 int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
1936 switch (evaluateFCmpRelation(C1, C2)) {
1937 default: llvm_unreachable("Unknown relation!");
1938 case FCmpInst::FCMP_UNO:
1939 case FCmpInst::FCMP_ORD:
1940 case FCmpInst::FCMP_UEQ:
1941 case FCmpInst::FCMP_UNE:
1942 case FCmpInst::FCMP_ULT:
1943 case FCmpInst::FCMP_UGT:
1944 case FCmpInst::FCMP_ULE:
1945 case FCmpInst::FCMP_UGE:
1946 case FCmpInst::FCMP_TRUE:
1947 case FCmpInst::FCMP_FALSE:
1948 case FCmpInst::BAD_FCMP_PREDICATE:
1949 break; // Couldn't determine anything about these constants.
1950 case FCmpInst::FCMP_OEQ: // We know that C1 == C2
1951 Result = (pred == FCmpInst::FCMP_UEQ || pred == FCmpInst::FCMP_OEQ ||
1952 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE ||
1953 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
1955 case FCmpInst::FCMP_OLT: // We know that C1 < C2
1956 Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
1957 pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT ||
1958 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE);
1960 case FCmpInst::FCMP_OGT: // We know that C1 > C2
1961 Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
1962 pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT ||
1963 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
1965 case FCmpInst::FCMP_OLE: // We know that C1 <= C2
1966 // We can only partially decide this relation.
1967 if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
1969 else if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
1972 case FCmpInst::FCMP_OGE: // We known that C1 >= C2
1973 // We can only partially decide this relation.
1974 if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
1976 else if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
1979 case ICmpInst::ICMP_NE: // We know that C1 != C2
1980 // We can only partially decide this relation.
1981 if (pred == FCmpInst::FCMP_OEQ || pred == FCmpInst::FCMP_UEQ)
1983 else if (pred == FCmpInst::FCMP_ONE || pred == FCmpInst::FCMP_UNE)
1988 // If we evaluated the result, return it now.
1990 return ConstantInt::get(ResultTy, Result);
1993 // Evaluate the relation between the two constants, per the predicate.
1994 int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
1995 switch (evaluateICmpRelation(C1, C2, CmpInst::isSigned(pred))) {
1996 default: llvm_unreachable("Unknown relational!");
1997 case ICmpInst::BAD_ICMP_PREDICATE:
1998 break; // Couldn't determine anything about these constants.
1999 case ICmpInst::ICMP_EQ: // We know the constants are equal!
2000 // If we know the constants are equal, we can decide the result of this
2001 // computation precisely.
2002 Result = ICmpInst::isTrueWhenEqual((ICmpInst::Predicate)pred);
2004 case ICmpInst::ICMP_ULT:
2006 case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_ULE:
2008 case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_UGE:
2012 case ICmpInst::ICMP_SLT:
2014 case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SLE:
2016 case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SGE:
2020 case ICmpInst::ICMP_UGT:
2022 case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_UGE:
2024 case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_ULE:
2028 case ICmpInst::ICMP_SGT:
2030 case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SGE:
2032 case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SLE:
2036 case ICmpInst::ICMP_ULE:
2037 if (pred == ICmpInst::ICMP_UGT) Result = 0;
2038 if (pred == ICmpInst::ICMP_ULT || pred == ICmpInst::ICMP_ULE) Result = 1;
2040 case ICmpInst::ICMP_SLE:
2041 if (pred == ICmpInst::ICMP_SGT) Result = 0;
2042 if (pred == ICmpInst::ICMP_SLT || pred == ICmpInst::ICMP_SLE) Result = 1;
2044 case ICmpInst::ICMP_UGE:
2045 if (pred == ICmpInst::ICMP_ULT) Result = 0;
2046 if (pred == ICmpInst::ICMP_UGT || pred == ICmpInst::ICMP_UGE) Result = 1;
2048 case ICmpInst::ICMP_SGE:
2049 if (pred == ICmpInst::ICMP_SLT) Result = 0;
2050 if (pred == ICmpInst::ICMP_SGT || pred == ICmpInst::ICMP_SGE) Result = 1;
2052 case ICmpInst::ICMP_NE:
2053 if (pred == ICmpInst::ICMP_EQ) Result = 0;
2054 if (pred == ICmpInst::ICMP_NE) Result = 1;
2058 // If we evaluated the result, return it now.
2060 return ConstantInt::get(ResultTy, Result);
2062 // If the right hand side is a bitcast, try using its inverse to simplify
2063 // it by moving it to the left hand side. We can't do this if it would turn
2064 // a vector compare into a scalar compare or visa versa.
2065 if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(C2)) {
2066 Constant *CE2Op0 = CE2->getOperand(0);
2067 if (CE2->getOpcode() == Instruction::BitCast &&
2068 isa<VectorType>(CE2->getType())==isa<VectorType>(CE2Op0->getType())) {
2069 Constant *Inverse = ConstantExpr::getBitCast(C1, CE2Op0->getType());
2070 return ConstantExpr::getICmp(pred, Inverse, CE2Op0);
2074 // If the left hand side is an extension, try eliminating it.
2075 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
2076 if (CE1->getOpcode() == Instruction::SExt ||
2077 CE1->getOpcode() == Instruction::ZExt) {
2078 Constant *CE1Op0 = CE1->getOperand(0);
2079 Constant *CE1Inverse = ConstantExpr::getTrunc(CE1, CE1Op0->getType());
2080 if (CE1Inverse == CE1Op0) {
2081 // Check whether we can safely truncate the right hand side.
2082 Constant *C2Inverse = ConstantExpr::getTrunc(C2, CE1Op0->getType());
2083 if (ConstantExpr::getZExt(C2Inverse, C2->getType()) == C2) {
2084 return ConstantExpr::getICmp(pred, CE1Inverse, C2Inverse);
2090 if ((!isa<ConstantExpr>(C1) && isa<ConstantExpr>(C2)) ||
2091 (C1->isNullValue() && !C2->isNullValue())) {
2092 // If C2 is a constant expr and C1 isn't, flip them around and fold the
2093 // other way if possible.
2094 // Also, if C1 is null and C2 isn't, flip them around.
2096 case ICmpInst::ICMP_EQ:
2097 case ICmpInst::ICMP_NE:
2098 // No change of predicate required.
2099 return ConstantExpr::getICmp(pred, C2, C1);
2101 case ICmpInst::ICMP_ULT:
2102 case ICmpInst::ICMP_SLT:
2103 case ICmpInst::ICMP_UGT:
2104 case ICmpInst::ICMP_SGT:
2105 case ICmpInst::ICMP_ULE:
2106 case ICmpInst::ICMP_SLE:
2107 case ICmpInst::ICMP_UGE:
2108 case ICmpInst::ICMP_SGE:
2109 // Change the predicate as necessary to swap the operands.
2110 pred = ICmpInst::getSwappedPredicate((ICmpInst::Predicate)pred);
2111 return ConstantExpr::getICmp(pred, C2, C1);
2113 default: // These predicates cannot be flopped around.
2121 /// isInBoundsIndices - Test whether the given sequence of *normalized* indices
2123 static bool isInBoundsIndices(Constant *const *Idxs, size_t NumIdx) {
2124 // No indices means nothing that could be out of bounds.
2125 if (NumIdx == 0) return true;
2127 // If the first index is zero, it's in bounds.
2128 if (Idxs[0]->isNullValue()) return true;
2130 // If the first index is one and all the rest are zero, it's in bounds,
2131 // by the one-past-the-end rule.
2132 if (!cast<ConstantInt>(Idxs[0])->isOne())
2134 for (unsigned i = 1, e = NumIdx; i != e; ++i)
2135 if (!Idxs[i]->isNullValue())
2140 Constant *llvm::ConstantFoldGetElementPtr(Constant *C,
2142 Constant* const *Idxs,
2145 (NumIdx == 1 && Idxs[0]->isNullValue()))
2148 if (isa<UndefValue>(C)) {
2149 const PointerType *Ptr = cast<PointerType>(C->getType());
2150 const Type *Ty = GetElementPtrInst::getIndexedType(Ptr,
2152 (Value **)Idxs+NumIdx);
2153 assert(Ty != 0 && "Invalid indices for GEP!");
2154 return UndefValue::get(PointerType::get(Ty, Ptr->getAddressSpace()));
2157 Constant *Idx0 = Idxs[0];
2158 if (C->isNullValue()) {
2160 for (unsigned i = 0, e = NumIdx; i != e; ++i)
2161 if (!Idxs[i]->isNullValue()) {
2166 const PointerType *Ptr = cast<PointerType>(C->getType());
2167 const Type *Ty = GetElementPtrInst::getIndexedType(Ptr,
2169 (Value**)Idxs+NumIdx);
2170 assert(Ty != 0 && "Invalid indices for GEP!");
2171 return ConstantPointerNull::get(
2172 PointerType::get(Ty,Ptr->getAddressSpace()));
2176 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2177 // Combine Indices - If the source pointer to this getelementptr instruction
2178 // is a getelementptr instruction, combine the indices of the two
2179 // getelementptr instructions into a single instruction.
2181 if (CE->getOpcode() == Instruction::GetElementPtr) {
2182 const Type *LastTy = 0;
2183 for (gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
2187 if ((LastTy && isa<ArrayType>(LastTy)) || Idx0->isNullValue()) {
2188 SmallVector<Value*, 16> NewIndices;
2189 NewIndices.reserve(NumIdx + CE->getNumOperands());
2190 for (unsigned i = 1, e = CE->getNumOperands()-1; i != e; ++i)
2191 NewIndices.push_back(CE->getOperand(i));
2193 // Add the last index of the source with the first index of the new GEP.
2194 // Make sure to handle the case when they are actually different types.
2195 Constant *Combined = CE->getOperand(CE->getNumOperands()-1);
2196 // Otherwise it must be an array.
2197 if (!Idx0->isNullValue()) {
2198 const Type *IdxTy = Combined->getType();
2199 if (IdxTy != Idx0->getType()) {
2200 const Type *Int64Ty = Type::getInt64Ty(IdxTy->getContext());
2201 Constant *C1 = ConstantExpr::getSExtOrBitCast(Idx0, Int64Ty);
2202 Constant *C2 = ConstantExpr::getSExtOrBitCast(Combined, Int64Ty);
2203 Combined = ConstantExpr::get(Instruction::Add, C1, C2);
2206 ConstantExpr::get(Instruction::Add, Idx0, Combined);
2210 NewIndices.push_back(Combined);
2211 NewIndices.insert(NewIndices.end(), Idxs+1, Idxs+NumIdx);
2212 return (inBounds && cast<GEPOperator>(CE)->isInBounds()) ?
2213 ConstantExpr::getInBoundsGetElementPtr(CE->getOperand(0),
2215 NewIndices.size()) :
2216 ConstantExpr::getGetElementPtr(CE->getOperand(0),
2222 // Implement folding of:
2223 // int* getelementptr ([2 x int]* bitcast ([3 x int]* %X to [2 x int]*),
2225 // To: int* getelementptr ([3 x int]* %X, long 0, long 0)
2227 if (CE->isCast() && NumIdx > 1 && Idx0->isNullValue()) {
2228 if (const PointerType *SPT =
2229 dyn_cast<PointerType>(CE->getOperand(0)->getType()))
2230 if (const ArrayType *SAT = dyn_cast<ArrayType>(SPT->getElementType()))
2231 if (const ArrayType *CAT =
2232 dyn_cast<ArrayType>(cast<PointerType>(C->getType())->getElementType()))
2233 if (CAT->getElementType() == SAT->getElementType())
2235 ConstantExpr::getInBoundsGetElementPtr(
2236 (Constant*)CE->getOperand(0), Idxs, NumIdx) :
2237 ConstantExpr::getGetElementPtr(
2238 (Constant*)CE->getOperand(0), Idxs, NumIdx);
2242 // Check to see if any array indices are not within the corresponding
2243 // notional array bounds. If so, try to determine if they can be factored
2244 // out into preceding dimensions.
2245 bool Unknown = false;
2246 SmallVector<Constant *, 8> NewIdxs;
2247 const Type *Ty = C->getType();
2248 const Type *Prev = 0;
2249 for (unsigned i = 0; i != NumIdx;
2250 Prev = Ty, Ty = cast<CompositeType>(Ty)->getTypeAtIndex(Idxs[i]), ++i) {
2251 if (ConstantInt *CI = dyn_cast<ConstantInt>(Idxs[i])) {
2252 if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty))
2253 if (ATy->getNumElements() <= INT64_MAX &&
2254 ATy->getNumElements() != 0 &&
2255 CI->getSExtValue() >= (int64_t)ATy->getNumElements()) {
2256 if (isa<SequentialType>(Prev)) {
2257 // It's out of range, but we can factor it into the prior
2259 NewIdxs.resize(NumIdx);
2260 ConstantInt *Factor = ConstantInt::get(CI->getType(),
2261 ATy->getNumElements());
2262 NewIdxs[i] = ConstantExpr::getSRem(CI, Factor);
2264 Constant *PrevIdx = Idxs[i-1];
2265 Constant *Div = ConstantExpr::getSDiv(CI, Factor);
2267 // Before adding, extend both operands to i64 to avoid
2268 // overflow trouble.
2269 if (!PrevIdx->getType()->isIntegerTy(64))
2270 PrevIdx = ConstantExpr::getSExt(PrevIdx,
2271 Type::getInt64Ty(Div->getContext()));
2272 if (!Div->getType()->isIntegerTy(64))
2273 Div = ConstantExpr::getSExt(Div,
2274 Type::getInt64Ty(Div->getContext()));
2276 NewIdxs[i-1] = ConstantExpr::getAdd(PrevIdx, Div);
2278 // It's out of range, but the prior dimension is a struct
2279 // so we can't do anything about it.
2284 // We don't know if it's in range or not.
2289 // If we did any factoring, start over with the adjusted indices.
2290 if (!NewIdxs.empty()) {
2291 for (unsigned i = 0; i != NumIdx; ++i)
2292 if (!NewIdxs[i]) NewIdxs[i] = Idxs[i];
2294 ConstantExpr::getInBoundsGetElementPtr(C, NewIdxs.data(),
2296 ConstantExpr::getGetElementPtr(C, NewIdxs.data(), NewIdxs.size());
2299 // If all indices are known integers and normalized, we can do a simple
2300 // check for the "inbounds" property.
2301 if (!Unknown && !inBounds &&
2302 isa<GlobalVariable>(C) && isInBoundsIndices(Idxs, NumIdx))
2303 return ConstantExpr::getInBoundsGetElementPtr(C, Idxs, NumIdx);