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) {
46 if (CV->isAllOnesValue()) return Constant::getAllOnesValue(DstTy);
47 if (CV->isNullValue()) return Constant::getNullValue(DstTy);
49 // If this cast changes element count then we can't handle it here:
50 // doing so requires endianness information. This should be handled by
51 // Analysis/ConstantFolding.cpp
52 unsigned NumElts = DstTy->getNumElements();
53 if (NumElts != CV->getNumOperands())
56 // Check to verify that all elements of the input are simple.
57 for (unsigned i = 0; i != NumElts; ++i) {
58 if (!isa<ConstantInt>(CV->getOperand(i)) &&
59 !isa<ConstantFP>(CV->getOperand(i)))
63 // Bitcast each element now.
64 std::vector<Constant*> Result;
65 const Type *DstEltTy = DstTy->getElementType();
66 for (unsigned i = 0; i != NumElts; ++i)
67 Result.push_back(ConstantExpr::getBitCast(CV->getOperand(i),
69 return ConstantVector::get(Result);
72 /// This function determines which opcode to use to fold two constant cast
73 /// expressions together. It uses CastInst::isEliminableCastPair to determine
74 /// the opcode. Consequently its just a wrapper around that function.
75 /// @brief Determine if it is valid to fold a cast of a cast
78 unsigned opc, ///< opcode of the second cast constant expression
79 ConstantExpr *Op, ///< the first cast constant expression
80 const Type *DstTy ///< desintation type of the first cast
82 assert(Op && Op->isCast() && "Can't fold cast of cast without a cast!");
83 assert(DstTy && DstTy->isFirstClassType() && "Invalid cast destination type");
84 assert(CastInst::isCast(opc) && "Invalid cast opcode");
86 // The the types and opcodes for the two Cast constant expressions
87 const Type *SrcTy = Op->getOperand(0)->getType();
88 const Type *MidTy = Op->getType();
89 Instruction::CastOps firstOp = Instruction::CastOps(Op->getOpcode());
90 Instruction::CastOps secondOp = Instruction::CastOps(opc);
92 // Let CastInst::isEliminableCastPair do the heavy lifting.
93 return CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy, DstTy,
94 Type::getInt64Ty(DstTy->getContext()));
97 static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
98 const Type *SrcTy = V->getType();
100 return V; // no-op cast
102 // Check to see if we are casting a pointer to an aggregate to a pointer to
103 // the first element. If so, return the appropriate GEP instruction.
104 if (const PointerType *PTy = dyn_cast<PointerType>(V->getType()))
105 if (const PointerType *DPTy = dyn_cast<PointerType>(DestTy))
106 if (PTy->getAddressSpace() == DPTy->getAddressSpace()) {
107 SmallVector<Value*, 8> IdxList;
109 Constant::getNullValue(Type::getInt32Ty(DPTy->getContext()));
110 IdxList.push_back(Zero);
111 const Type *ElTy = PTy->getElementType();
112 while (ElTy != DPTy->getElementType()) {
113 if (const StructType *STy = dyn_cast<StructType>(ElTy)) {
114 if (STy->getNumElements() == 0) break;
115 ElTy = STy->getElementType(0);
116 IdxList.push_back(Zero);
117 } else if (const SequentialType *STy =
118 dyn_cast<SequentialType>(ElTy)) {
119 if (ElTy->isPointerTy()) break; // Can't index into pointers!
120 ElTy = STy->getElementType();
121 IdxList.push_back(Zero);
127 if (ElTy == DPTy->getElementType())
128 // This GEP is inbounds because all indices are zero.
129 return ConstantExpr::getInBoundsGetElementPtr(V, &IdxList[0],
133 // Handle casts from one vector constant to another. We know that the src
134 // and dest type have the same size (otherwise its an illegal cast).
135 if (const VectorType *DestPTy = dyn_cast<VectorType>(DestTy)) {
136 if (const VectorType *SrcTy = dyn_cast<VectorType>(V->getType())) {
137 assert(DestPTy->getBitWidth() == SrcTy->getBitWidth() &&
138 "Not cast between same sized vectors!");
140 // First, check for null. Undef is already handled.
141 if (isa<ConstantAggregateZero>(V))
142 return Constant::getNullValue(DestTy);
144 if (ConstantVector *CV = dyn_cast<ConstantVector>(V))
145 return BitCastConstantVector(CV, DestPTy);
148 // Canonicalize scalar-to-vector bitcasts into vector-to-vector bitcasts
149 // This allows for other simplifications (although some of them
150 // can only be handled by Analysis/ConstantFolding.cpp).
151 if (isa<ConstantInt>(V) || isa<ConstantFP>(V))
152 return ConstantExpr::getBitCast(ConstantVector::get(V), DestPTy);
155 // Finally, implement bitcast folding now. The code below doesn't handle
157 if (isa<ConstantPointerNull>(V)) // ptr->ptr cast.
158 return ConstantPointerNull::get(cast<PointerType>(DestTy));
160 // Handle integral constant input.
161 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
162 if (DestTy->isIntegerTy())
163 // Integral -> Integral. This is a no-op because the bit widths must
164 // be the same. Consequently, we just fold to V.
167 if (DestTy->isFloatingPointTy())
168 return ConstantFP::get(DestTy->getContext(),
169 APFloat(CI->getValue(),
170 !DestTy->isPPC_FP128Ty()));
172 // Otherwise, can't fold this (vector?)
176 // Handle ConstantFP input: FP -> Integral.
177 if (ConstantFP *FP = dyn_cast<ConstantFP>(V))
178 return ConstantInt::get(FP->getContext(),
179 FP->getValueAPF().bitcastToAPInt());
185 /// ExtractConstantBytes - V is an integer constant which only has a subset of
186 /// its bytes used. The bytes used are indicated by ByteStart (which is the
187 /// first byte used, counting from the least significant byte) and ByteSize,
188 /// which is the number of bytes used.
190 /// This function analyzes the specified constant to see if the specified byte
191 /// range can be returned as a simplified constant. If so, the constant is
192 /// returned, otherwise null is returned.
194 static Constant *ExtractConstantBytes(Constant *C, unsigned ByteStart,
196 assert(C->getType()->isIntegerTy() &&
197 (cast<IntegerType>(C->getType())->getBitWidth() & 7) == 0 &&
198 "Non-byte sized integer input");
199 unsigned CSize = cast<IntegerType>(C->getType())->getBitWidth()/8;
200 assert(ByteSize && "Must be accessing some piece");
201 assert(ByteStart+ByteSize <= CSize && "Extracting invalid piece from input");
202 assert(ByteSize != CSize && "Should not extract everything");
204 // Constant Integers are simple.
205 if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
206 APInt V = CI->getValue();
208 V = V.lshr(ByteStart*8);
209 V = V.trunc(ByteSize*8);
210 return ConstantInt::get(CI->getContext(), V);
213 // In the input is a constant expr, we might be able to recursively simplify.
214 // If not, we definitely can't do anything.
215 ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
216 if (CE == 0) return 0;
218 switch (CE->getOpcode()) {
220 case Instruction::Or: {
221 Constant *RHS = ExtractConstantBytes(CE->getOperand(1), ByteStart,ByteSize);
226 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS))
227 if (RHSC->isAllOnesValue())
230 Constant *LHS = ExtractConstantBytes(CE->getOperand(0), ByteStart,ByteSize);
233 return ConstantExpr::getOr(LHS, RHS);
235 case Instruction::And: {
236 Constant *RHS = ExtractConstantBytes(CE->getOperand(1), ByteStart,ByteSize);
241 if (RHS->isNullValue())
244 Constant *LHS = ExtractConstantBytes(CE->getOperand(0), ByteStart,ByteSize);
247 return ConstantExpr::getAnd(LHS, RHS);
249 case Instruction::LShr: {
250 ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
253 unsigned ShAmt = Amt->getZExtValue();
254 // Cannot analyze non-byte shifts.
255 if ((ShAmt & 7) != 0)
259 // If the extract is known to be all zeros, return zero.
260 if (ByteStart >= CSize-ShAmt)
261 return Constant::getNullValue(IntegerType::get(CE->getContext(),
263 // If the extract is known to be fully in the input, extract it.
264 if (ByteStart+ByteSize+ShAmt <= CSize)
265 return ExtractConstantBytes(CE->getOperand(0), ByteStart+ShAmt, ByteSize);
267 // TODO: Handle the 'partially zero' case.
271 case Instruction::Shl: {
272 ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
275 unsigned ShAmt = Amt->getZExtValue();
276 // Cannot analyze non-byte shifts.
277 if ((ShAmt & 7) != 0)
281 // If the extract is known to be all zeros, return zero.
282 if (ByteStart+ByteSize <= ShAmt)
283 return Constant::getNullValue(IntegerType::get(CE->getContext(),
285 // If the extract is known to be fully in the input, extract it.
286 if (ByteStart >= ShAmt)
287 return ExtractConstantBytes(CE->getOperand(0), ByteStart-ShAmt, ByteSize);
289 // TODO: Handle the 'partially zero' case.
293 case Instruction::ZExt: {
294 unsigned SrcBitSize =
295 cast<IntegerType>(CE->getOperand(0)->getType())->getBitWidth();
297 // If extracting something that is completely zero, return 0.
298 if (ByteStart*8 >= SrcBitSize)
299 return Constant::getNullValue(IntegerType::get(CE->getContext(),
302 // If exactly extracting the input, return it.
303 if (ByteStart == 0 && ByteSize*8 == SrcBitSize)
304 return CE->getOperand(0);
306 // If extracting something completely in the input, if if the input is a
307 // multiple of 8 bits, recurse.
308 if ((SrcBitSize&7) == 0 && (ByteStart+ByteSize)*8 <= SrcBitSize)
309 return ExtractConstantBytes(CE->getOperand(0), ByteStart, ByteSize);
311 // Otherwise, if extracting a subset of the input, which is not multiple of
312 // 8 bits, do a shift and trunc to get the bits.
313 if ((ByteStart+ByteSize)*8 < SrcBitSize) {
314 assert((SrcBitSize&7) && "Shouldn't get byte sized case here");
315 Constant *Res = CE->getOperand(0);
317 Res = ConstantExpr::getLShr(Res,
318 ConstantInt::get(Res->getType(), ByteStart*8));
319 return ConstantExpr::getTrunc(Res, IntegerType::get(C->getContext(),
323 // TODO: Handle the 'partially zero' case.
329 /// getFoldedSizeOf - Return a ConstantExpr with type DestTy for sizeof
330 /// on Ty, with any known factors factored out. If Folded is false,
331 /// return null if no factoring was possible, to avoid endlessly
332 /// bouncing an unfoldable expression back into the top-level folder.
334 static Constant *getFoldedSizeOf(const Type *Ty, const Type *DestTy,
336 if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
337 Constant *N = ConstantInt::get(DestTy, ATy->getNumElements());
338 Constant *E = getFoldedSizeOf(ATy->getElementType(), DestTy, true);
339 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);
468 if (const StructType *STy = dyn_cast<StructType>(Ty))
469 if (!STy->isPacked()) {
470 unsigned NumElems = STy->getNumElements();
471 // An empty struct has no members.
474 // Check for a struct with all members having the same size.
475 Constant *MemberSize =
476 getFoldedSizeOf(STy->getElementType(0), DestTy, true);
478 for (unsigned i = 1; i != NumElems; ++i)
480 getFoldedSizeOf(STy->getElementType(i), DestTy, true)) {
485 Constant *N = ConstantExpr::getCast(CastInst::getCastOpcode(FieldNo,
490 return ConstantExpr::getNUWMul(MemberSize, N);
494 // If there's no interesting folding happening, bail so that we don't create
495 // a constant that looks like it needs folding but really doesn't.
499 // Base case: Get a regular offsetof expression.
500 Constant *C = ConstantExpr::getOffsetOf(Ty, FieldNo);
501 C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
507 Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V,
508 const Type *DestTy) {
509 if (isa<UndefValue>(V)) {
510 // zext(undef) = 0, because the top bits will be zero.
511 // sext(undef) = 0, because the top bits will all be the same.
512 // [us]itofp(undef) = 0, because the result value is bounded.
513 if (opc == Instruction::ZExt || opc == Instruction::SExt ||
514 opc == Instruction::UIToFP || opc == Instruction::SIToFP)
515 return Constant::getNullValue(DestTy);
516 return UndefValue::get(DestTy);
519 // No compile-time operations on this type yet.
520 if (V->getType()->isPPC_FP128Ty() || DestTy->isPPC_FP128Ty())
523 if (V->isNullValue() && !DestTy->isX86_MMXTy())
524 return Constant::getNullValue(DestTy);
526 // If the cast operand is a constant expression, there's a few things we can
527 // do to try to simplify it.
528 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
530 // Try hard to fold cast of cast because they are often eliminable.
531 if (unsigned newOpc = foldConstantCastPair(opc, CE, DestTy))
532 return ConstantExpr::getCast(newOpc, CE->getOperand(0), DestTy);
533 } else if (CE->getOpcode() == Instruction::GetElementPtr) {
534 // If all of the indexes in the GEP are null values, there is no pointer
535 // adjustment going on. We might as well cast the source pointer.
536 bool isAllNull = true;
537 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
538 if (!CE->getOperand(i)->isNullValue()) {
543 // This is casting one pointer type to another, always BitCast
544 return ConstantExpr::getPointerCast(CE->getOperand(0), DestTy);
548 // If the cast operand is a constant vector, perform the cast by
549 // operating on each element. In the cast of bitcasts, the element
550 // count may be mismatched; don't attempt to handle that here.
551 if (ConstantVector *CV = dyn_cast<ConstantVector>(V))
552 if (DestTy->isVectorTy() &&
553 cast<VectorType>(DestTy)->getNumElements() ==
554 CV->getType()->getNumElements()) {
555 std::vector<Constant*> res;
556 const VectorType *DestVecTy = cast<VectorType>(DestTy);
557 const Type *DstEltTy = DestVecTy->getElementType();
558 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
559 res.push_back(ConstantExpr::getCast(opc,
560 CV->getOperand(i), DstEltTy));
561 return ConstantVector::get(DestVecTy, res);
564 // We actually have to do a cast now. Perform the cast according to the
568 llvm_unreachable("Failed to cast constant expression");
569 case Instruction::FPTrunc:
570 case Instruction::FPExt:
571 if (ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
573 APFloat Val = FPC->getValueAPF();
574 Val.convert(DestTy->isFloatTy() ? APFloat::IEEEsingle :
575 DestTy->isDoubleTy() ? APFloat::IEEEdouble :
576 DestTy->isX86_FP80Ty() ? APFloat::x87DoubleExtended :
577 DestTy->isFP128Ty() ? APFloat::IEEEquad :
579 APFloat::rmNearestTiesToEven, &ignored);
580 return ConstantFP::get(V->getContext(), Val);
582 return 0; // Can't fold.
583 case Instruction::FPToUI:
584 case Instruction::FPToSI:
585 if (ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
586 const APFloat &V = FPC->getValueAPF();
589 uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
590 (void) V.convertToInteger(x, DestBitWidth, opc==Instruction::FPToSI,
591 APFloat::rmTowardZero, &ignored);
592 APInt Val(DestBitWidth, 2, x);
593 return ConstantInt::get(FPC->getContext(), Val);
595 return 0; // Can't fold.
596 case Instruction::IntToPtr: //always treated as unsigned
597 if (V->isNullValue()) // Is it an integral null value?
598 return ConstantPointerNull::get(cast<PointerType>(DestTy));
599 return 0; // Other pointer types cannot be casted
600 case Instruction::PtrToInt: // always treated as unsigned
601 // Is it a null pointer value?
602 if (V->isNullValue())
603 return ConstantInt::get(DestTy, 0);
604 // If this is a sizeof-like expression, pull out multiplications by
605 // known factors to expose them to subsequent folding. If it's an
606 // alignof-like expression, factor out known factors.
607 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
608 if (CE->getOpcode() == Instruction::GetElementPtr &&
609 CE->getOperand(0)->isNullValue()) {
611 cast<PointerType>(CE->getOperand(0)->getType())->getElementType();
612 if (CE->getNumOperands() == 2) {
613 // Handle a sizeof-like expression.
614 Constant *Idx = CE->getOperand(1);
615 bool isOne = isa<ConstantInt>(Idx) && cast<ConstantInt>(Idx)->isOne();
616 if (Constant *C = getFoldedSizeOf(Ty, DestTy, !isOne)) {
617 Idx = ConstantExpr::getCast(CastInst::getCastOpcode(Idx, true,
620 return ConstantExpr::getMul(C, Idx);
622 } else if (CE->getNumOperands() == 3 &&
623 CE->getOperand(1)->isNullValue()) {
624 // Handle an alignof-like expression.
625 if (const StructType *STy = dyn_cast<StructType>(Ty))
626 if (!STy->isPacked()) {
627 ConstantInt *CI = cast<ConstantInt>(CE->getOperand(2));
629 STy->getNumElements() == 2 &&
630 STy->getElementType(0)->isIntegerTy(1)) {
631 return getFoldedAlignOf(STy->getElementType(1), DestTy, false);
634 // Handle an offsetof-like expression.
635 if (Ty->isStructTy() || Ty->isArrayTy()) {
636 if (Constant *C = getFoldedOffsetOf(Ty, CE->getOperand(2),
642 // Other pointer types cannot be casted
644 case Instruction::UIToFP:
645 case Instruction::SIToFP:
646 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
647 APInt api = CI->getValue();
648 APFloat apf(APInt::getNullValue(DestTy->getPrimitiveSizeInBits()), true);
649 (void)apf.convertFromAPInt(api,
650 opc==Instruction::SIToFP,
651 APFloat::rmNearestTiesToEven);
652 return ConstantFP::get(V->getContext(), apf);
655 case Instruction::ZExt:
656 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
657 uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
658 return ConstantInt::get(V->getContext(),
659 CI->getValue().zext(BitWidth));
662 case Instruction::SExt:
663 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
664 uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
665 return ConstantInt::get(V->getContext(),
666 CI->getValue().sext(BitWidth));
669 case Instruction::Trunc: {
670 uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
671 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
672 return ConstantInt::get(V->getContext(),
673 CI->getValue().trunc(DestBitWidth));
676 // The input must be a constantexpr. See if we can simplify this based on
677 // the bytes we are demanding. Only do this if the source and dest are an
678 // even multiple of a byte.
679 if ((DestBitWidth & 7) == 0 &&
680 (cast<IntegerType>(V->getType())->getBitWidth() & 7) == 0)
681 if (Constant *Res = ExtractConstantBytes(V, 0, DestBitWidth / 8))
686 case Instruction::BitCast:
687 return FoldBitCast(V, DestTy);
691 Constant *llvm::ConstantFoldSelectInstruction(Constant *Cond,
692 Constant *V1, Constant *V2) {
693 if (ConstantInt *CB = dyn_cast<ConstantInt>(Cond))
694 return CB->getZExtValue() ? V1 : V2;
696 // Check for zero aggregate and ConstantVector of zeros
697 if (Cond->isNullValue()) return V2;
699 if (ConstantVector* CondV = dyn_cast<ConstantVector>(Cond)) {
701 if (CondV->isAllOnesValue()) return V1;
703 const VectorType *VTy = cast<VectorType>(V1->getType());
704 ConstantVector *CP1 = dyn_cast<ConstantVector>(V1);
705 ConstantVector *CP2 = dyn_cast<ConstantVector>(V2);
707 if ((CP1 || isa<ConstantAggregateZero>(V1)) &&
708 (CP2 || isa<ConstantAggregateZero>(V2))) {
710 // Find the element type of the returned vector
711 const Type *EltTy = VTy->getElementType();
712 unsigned NumElem = VTy->getNumElements();
713 std::vector<Constant*> Res(NumElem);
716 for (unsigned i = 0; i < NumElem; ++i) {
717 ConstantInt* c = dyn_cast<ConstantInt>(CondV->getOperand(i));
722 Constant *C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
723 Constant *C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
724 Res[i] = c->getZExtValue() ? C1 : C2;
726 // If we were able to build the vector, return it
727 if (Valid) return ConstantVector::get(Res);
732 if (isa<UndefValue>(V1)) return V2;
733 if (isa<UndefValue>(V2)) return V1;
734 if (isa<UndefValue>(Cond)) return V1;
735 if (V1 == V2) return V1;
737 if (ConstantExpr *TrueVal = dyn_cast<ConstantExpr>(V1)) {
738 if (TrueVal->getOpcode() == Instruction::Select)
739 if (TrueVal->getOperand(0) == Cond)
740 return ConstantExpr::getSelect(Cond, TrueVal->getOperand(1), V2);
742 if (ConstantExpr *FalseVal = dyn_cast<ConstantExpr>(V2)) {
743 if (FalseVal->getOpcode() == Instruction::Select)
744 if (FalseVal->getOperand(0) == Cond)
745 return ConstantExpr::getSelect(Cond, V1, FalseVal->getOperand(2));
751 Constant *llvm::ConstantFoldExtractElementInstruction(Constant *Val,
753 if (isa<UndefValue>(Val)) // ee(undef, x) -> undef
754 return UndefValue::get(cast<VectorType>(Val->getType())->getElementType());
755 if (Val->isNullValue()) // ee(zero, x) -> zero
756 return Constant::getNullValue(
757 cast<VectorType>(Val->getType())->getElementType());
759 if (ConstantVector *CVal = dyn_cast<ConstantVector>(Val)) {
760 if (ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx)) {
761 return CVal->getOperand(CIdx->getZExtValue());
762 } else if (isa<UndefValue>(Idx)) {
763 // ee({w,x,y,z}, undef) -> w (an arbitrary value).
764 return CVal->getOperand(0);
770 Constant *llvm::ConstantFoldInsertElementInstruction(Constant *Val,
773 ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx);
775 APInt idxVal = CIdx->getValue();
776 if (isa<UndefValue>(Val)) {
777 // Insertion of scalar constant into vector undef
778 // Optimize away insertion of undef
779 if (isa<UndefValue>(Elt))
781 // Otherwise break the aggregate undef into multiple undefs and do
784 cast<VectorType>(Val->getType())->getNumElements();
785 std::vector<Constant*> Ops;
787 for (unsigned i = 0; i < numOps; ++i) {
789 (idxVal == i) ? Elt : UndefValue::get(Elt->getType());
792 return ConstantVector::get(Ops);
794 if (isa<ConstantAggregateZero>(Val)) {
795 // Insertion of scalar constant into vector aggregate zero
796 // Optimize away insertion of zero
797 if (Elt->isNullValue())
799 // Otherwise break the aggregate zero into multiple zeros and do
802 cast<VectorType>(Val->getType())->getNumElements();
803 std::vector<Constant*> Ops;
805 for (unsigned i = 0; i < numOps; ++i) {
807 (idxVal == i) ? Elt : Constant::getNullValue(Elt->getType());
810 return ConstantVector::get(Ops);
812 if (ConstantVector *CVal = dyn_cast<ConstantVector>(Val)) {
813 // Insertion of scalar constant into vector constant
814 std::vector<Constant*> Ops;
815 Ops.reserve(CVal->getNumOperands());
816 for (unsigned i = 0; i < CVal->getNumOperands(); ++i) {
818 (idxVal == i) ? Elt : cast<Constant>(CVal->getOperand(i));
821 return ConstantVector::get(Ops);
827 /// GetVectorElement - If C is a ConstantVector, ConstantAggregateZero or Undef
828 /// return the specified element value. Otherwise return null.
829 static Constant *GetVectorElement(Constant *C, unsigned EltNo) {
830 if (ConstantVector *CV = dyn_cast<ConstantVector>(C))
831 return CV->getOperand(EltNo);
833 const Type *EltTy = cast<VectorType>(C->getType())->getElementType();
834 if (isa<ConstantAggregateZero>(C))
835 return Constant::getNullValue(EltTy);
836 if (isa<UndefValue>(C))
837 return UndefValue::get(EltTy);
841 Constant *llvm::ConstantFoldShuffleVectorInstruction(Constant *V1,
844 // Undefined shuffle mask -> undefined value.
845 if (isa<UndefValue>(Mask)) return UndefValue::get(V1->getType());
847 unsigned MaskNumElts = cast<VectorType>(Mask->getType())->getNumElements();
848 unsigned SrcNumElts = cast<VectorType>(V1->getType())->getNumElements();
849 const Type *EltTy = cast<VectorType>(V1->getType())->getElementType();
851 // Loop over the shuffle mask, evaluating each element.
852 SmallVector<Constant*, 32> Result;
853 for (unsigned i = 0; i != MaskNumElts; ++i) {
854 Constant *InElt = GetVectorElement(Mask, i);
855 if (InElt == 0) return 0;
857 if (isa<UndefValue>(InElt))
858 InElt = UndefValue::get(EltTy);
859 else if (ConstantInt *CI = dyn_cast<ConstantInt>(InElt)) {
860 unsigned Elt = CI->getZExtValue();
861 if (Elt >= SrcNumElts*2)
862 InElt = UndefValue::get(EltTy);
863 else if (Elt >= SrcNumElts)
864 InElt = GetVectorElement(V2, Elt - SrcNumElts);
866 InElt = GetVectorElement(V1, Elt);
867 if (InElt == 0) return 0;
872 Result.push_back(InElt);
875 return ConstantVector::get(Result);
878 Constant *llvm::ConstantFoldExtractValueInstruction(Constant *Agg,
879 const unsigned *Idxs,
881 // Base case: no indices, so return the entire value.
885 if (isa<UndefValue>(Agg)) // ev(undef, x) -> undef
886 return UndefValue::get(ExtractValueInst::getIndexedType(Agg->getType(),
890 if (isa<ConstantAggregateZero>(Agg)) // ev(0, x) -> 0
892 Constant::getNullValue(ExtractValueInst::getIndexedType(Agg->getType(),
896 // Otherwise recurse.
897 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(Agg))
898 return ConstantFoldExtractValueInstruction(CS->getOperand(*Idxs),
901 if (ConstantArray *CA = dyn_cast<ConstantArray>(Agg))
902 return ConstantFoldExtractValueInstruction(CA->getOperand(*Idxs),
904 ConstantVector *CV = cast<ConstantVector>(Agg);
905 return ConstantFoldExtractValueInstruction(CV->getOperand(*Idxs),
909 Constant *llvm::ConstantFoldInsertValueInstruction(Constant *Agg,
911 const unsigned *Idxs,
913 // Base case: no indices, so replace the entire value.
917 if (isa<UndefValue>(Agg)) {
918 // Insertion of constant into aggregate undef
919 // Optimize away insertion of undef.
920 if (isa<UndefValue>(Val))
923 // Otherwise break the aggregate undef into multiple undefs and do
925 const CompositeType *AggTy = cast<CompositeType>(Agg->getType());
927 if (const ArrayType *AR = dyn_cast<ArrayType>(AggTy))
928 numOps = AR->getNumElements();
930 numOps = cast<StructType>(AggTy)->getNumElements();
932 std::vector<Constant*> Ops(numOps);
933 for (unsigned i = 0; i < numOps; ++i) {
934 const Type *MemberTy = AggTy->getTypeAtIndex(i);
937 ConstantFoldInsertValueInstruction(UndefValue::get(MemberTy),
938 Val, Idxs+1, NumIdx-1) :
939 UndefValue::get(MemberTy);
943 if (const StructType* ST = dyn_cast<StructType>(AggTy))
944 return ConstantStruct::get(ST->getContext(), Ops, ST->isPacked());
945 return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
948 if (isa<ConstantAggregateZero>(Agg)) {
949 // Insertion of constant into aggregate zero
950 // Optimize away insertion of zero.
951 if (Val->isNullValue())
954 // Otherwise break the aggregate zero into multiple zeros and do
956 const CompositeType *AggTy = cast<CompositeType>(Agg->getType());
958 if (const ArrayType *AR = dyn_cast<ArrayType>(AggTy))
959 numOps = AR->getNumElements();
961 numOps = cast<StructType>(AggTy)->getNumElements();
963 std::vector<Constant*> Ops(numOps);
964 for (unsigned i = 0; i < numOps; ++i) {
965 const Type *MemberTy = AggTy->getTypeAtIndex(i);
968 ConstantFoldInsertValueInstruction(Constant::getNullValue(MemberTy),
969 Val, Idxs+1, NumIdx-1) :
970 Constant::getNullValue(MemberTy);
974 if (const StructType *ST = dyn_cast<StructType>(AggTy))
975 return ConstantStruct::get(ST->getContext(), Ops, ST->isPacked());
976 return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
979 if (isa<ConstantStruct>(Agg) || isa<ConstantArray>(Agg)) {
980 // Insertion of constant into aggregate constant.
981 std::vector<Constant*> Ops(Agg->getNumOperands());
982 for (unsigned i = 0; i < Agg->getNumOperands(); ++i) {
983 Constant *Op = cast<Constant>(Agg->getOperand(i));
985 Op = ConstantFoldInsertValueInstruction(Op, Val, Idxs+1, NumIdx-1);
989 if (const StructType* ST = dyn_cast<StructType>(Agg->getType()))
990 return ConstantStruct::get(ST->getContext(), Ops, ST->isPacked());
991 return ConstantArray::get(cast<ArrayType>(Agg->getType()), Ops);
998 Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
999 Constant *C1, Constant *C2) {
1000 // No compile-time operations on this type yet.
1001 if (C1->getType()->isPPC_FP128Ty())
1004 // Handle UndefValue up front.
1005 if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
1007 case Instruction::Xor:
1008 if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
1009 // Handle undef ^ undef -> 0 special case. This is a common
1011 return Constant::getNullValue(C1->getType());
1013 case Instruction::Add:
1014 case Instruction::Sub:
1015 return UndefValue::get(C1->getType());
1016 case Instruction::Mul:
1017 case Instruction::And:
1018 return Constant::getNullValue(C1->getType());
1019 case Instruction::UDiv:
1020 case Instruction::SDiv:
1021 case Instruction::URem:
1022 case Instruction::SRem:
1023 if (!isa<UndefValue>(C2)) // undef / X -> 0
1024 return Constant::getNullValue(C1->getType());
1025 return C2; // X / undef -> undef
1026 case Instruction::Or: // X | undef -> -1
1027 if (const VectorType *PTy = dyn_cast<VectorType>(C1->getType()))
1028 return Constant::getAllOnesValue(PTy);
1029 return Constant::getAllOnesValue(C1->getType());
1030 case Instruction::LShr:
1031 if (isa<UndefValue>(C2) && isa<UndefValue>(C1))
1032 return C1; // undef lshr undef -> undef
1033 return Constant::getNullValue(C1->getType()); // X lshr undef -> 0
1034 // undef lshr X -> 0
1035 case Instruction::AShr:
1036 if (!isa<UndefValue>(C2)) // undef ashr X --> all ones
1037 return Constant::getAllOnesValue(C1->getType());
1038 else if (isa<UndefValue>(C1))
1039 return C1; // undef ashr undef -> undef
1041 return C1; // X ashr undef --> X
1042 case Instruction::Shl:
1043 // undef << X -> 0 or X << undef -> 0
1044 return Constant::getNullValue(C1->getType());
1048 // Handle simplifications when the RHS is a constant int.
1049 if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
1051 case Instruction::Add:
1052 if (CI2->equalsInt(0)) return C1; // X + 0 == X
1054 case Instruction::Sub:
1055 if (CI2->equalsInt(0)) return C1; // X - 0 == X
1057 case Instruction::Mul:
1058 if (CI2->equalsInt(0)) return C2; // X * 0 == 0
1059 if (CI2->equalsInt(1))
1060 return C1; // X * 1 == X
1062 case Instruction::UDiv:
1063 case Instruction::SDiv:
1064 if (CI2->equalsInt(1))
1065 return C1; // X / 1 == X
1066 if (CI2->equalsInt(0))
1067 return UndefValue::get(CI2->getType()); // X / 0 == undef
1069 case Instruction::URem:
1070 case Instruction::SRem:
1071 if (CI2->equalsInt(1))
1072 return Constant::getNullValue(CI2->getType()); // X % 1 == 0
1073 if (CI2->equalsInt(0))
1074 return UndefValue::get(CI2->getType()); // X % 0 == undef
1076 case Instruction::And:
1077 if (CI2->isZero()) return C2; // X & 0 == 0
1078 if (CI2->isAllOnesValue())
1079 return C1; // X & -1 == X
1081 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1082 // (zext i32 to i64) & 4294967295 -> (zext i32 to i64)
1083 if (CE1->getOpcode() == Instruction::ZExt) {
1084 unsigned DstWidth = CI2->getType()->getBitWidth();
1086 CE1->getOperand(0)->getType()->getPrimitiveSizeInBits();
1087 APInt PossiblySetBits(APInt::getLowBitsSet(DstWidth, SrcWidth));
1088 if ((PossiblySetBits & CI2->getValue()) == PossiblySetBits)
1092 // If and'ing the address of a global with a constant, fold it.
1093 if (CE1->getOpcode() == Instruction::PtrToInt &&
1094 isa<GlobalValue>(CE1->getOperand(0))) {
1095 GlobalValue *GV = cast<GlobalValue>(CE1->getOperand(0));
1097 // Functions are at least 4-byte aligned.
1098 unsigned GVAlign = GV->getAlignment();
1099 if (isa<Function>(GV))
1100 GVAlign = std::max(GVAlign, 4U);
1103 unsigned DstWidth = CI2->getType()->getBitWidth();
1104 unsigned SrcWidth = std::min(DstWidth, Log2_32(GVAlign));
1105 APInt BitsNotSet(APInt::getLowBitsSet(DstWidth, SrcWidth));
1107 // If checking bits we know are clear, return zero.
1108 if ((CI2->getValue() & BitsNotSet) == CI2->getValue())
1109 return Constant::getNullValue(CI2->getType());
1114 case Instruction::Or:
1115 if (CI2->equalsInt(0)) return C1; // X | 0 == X
1116 if (CI2->isAllOnesValue())
1117 return C2; // X | -1 == -1
1119 case Instruction::Xor:
1120 if (CI2->equalsInt(0)) return C1; // X ^ 0 == X
1122 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1123 switch (CE1->getOpcode()) {
1125 case Instruction::ICmp:
1126 case Instruction::FCmp:
1127 // cmp pred ^ true -> cmp !pred
1128 assert(CI2->equalsInt(1));
1129 CmpInst::Predicate pred = (CmpInst::Predicate)CE1->getPredicate();
1130 pred = CmpInst::getInversePredicate(pred);
1131 return ConstantExpr::getCompare(pred, CE1->getOperand(0),
1132 CE1->getOperand(1));
1136 case Instruction::AShr:
1137 // ashr (zext C to Ty), C2 -> lshr (zext C, CSA), C2
1138 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1))
1139 if (CE1->getOpcode() == Instruction::ZExt) // Top bits known zero.
1140 return ConstantExpr::getLShr(C1, C2);
1143 } else if (isa<ConstantInt>(C1)) {
1144 // If C1 is a ConstantInt and C2 is not, swap the operands.
1145 if (Instruction::isCommutative(Opcode))
1146 return ConstantExpr::get(Opcode, C2, C1);
1149 // At this point we know neither constant is an UndefValue.
1150 if (ConstantInt *CI1 = dyn_cast<ConstantInt>(C1)) {
1151 if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
1152 using namespace APIntOps;
1153 const APInt &C1V = CI1->getValue();
1154 const APInt &C2V = CI2->getValue();
1158 case Instruction::Add:
1159 return ConstantInt::get(CI1->getContext(), C1V + C2V);
1160 case Instruction::Sub:
1161 return ConstantInt::get(CI1->getContext(), C1V - C2V);
1162 case Instruction::Mul:
1163 return ConstantInt::get(CI1->getContext(), C1V * C2V);
1164 case Instruction::UDiv:
1165 assert(!CI2->isNullValue() && "Div by zero handled above");
1166 return ConstantInt::get(CI1->getContext(), C1V.udiv(C2V));
1167 case Instruction::SDiv:
1168 assert(!CI2->isNullValue() && "Div by zero handled above");
1169 if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
1170 return UndefValue::get(CI1->getType()); // MIN_INT / -1 -> undef
1171 return ConstantInt::get(CI1->getContext(), C1V.sdiv(C2V));
1172 case Instruction::URem:
1173 assert(!CI2->isNullValue() && "Div by zero handled above");
1174 return ConstantInt::get(CI1->getContext(), C1V.urem(C2V));
1175 case Instruction::SRem:
1176 assert(!CI2->isNullValue() && "Div by zero handled above");
1177 if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
1178 return UndefValue::get(CI1->getType()); // MIN_INT % -1 -> undef
1179 return ConstantInt::get(CI1->getContext(), C1V.srem(C2V));
1180 case Instruction::And:
1181 return ConstantInt::get(CI1->getContext(), C1V & C2V);
1182 case Instruction::Or:
1183 return ConstantInt::get(CI1->getContext(), C1V | C2V);
1184 case Instruction::Xor:
1185 return ConstantInt::get(CI1->getContext(), C1V ^ C2V);
1186 case Instruction::Shl: {
1187 uint32_t shiftAmt = C2V.getZExtValue();
1188 if (shiftAmt < C1V.getBitWidth())
1189 return ConstantInt::get(CI1->getContext(), C1V.shl(shiftAmt));
1191 return UndefValue::get(C1->getType()); // too big shift is undef
1193 case Instruction::LShr: {
1194 uint32_t shiftAmt = C2V.getZExtValue();
1195 if (shiftAmt < C1V.getBitWidth())
1196 return ConstantInt::get(CI1->getContext(), C1V.lshr(shiftAmt));
1198 return UndefValue::get(C1->getType()); // too big shift is undef
1200 case Instruction::AShr: {
1201 uint32_t shiftAmt = C2V.getZExtValue();
1202 if (shiftAmt < C1V.getBitWidth())
1203 return ConstantInt::get(CI1->getContext(), C1V.ashr(shiftAmt));
1205 return UndefValue::get(C1->getType()); // too big shift is undef
1211 case Instruction::SDiv:
1212 case Instruction::UDiv:
1213 case Instruction::URem:
1214 case Instruction::SRem:
1215 case Instruction::LShr:
1216 case Instruction::AShr:
1217 case Instruction::Shl:
1218 if (CI1->equalsInt(0)) return C1;
1223 } else if (ConstantFP *CFP1 = dyn_cast<ConstantFP>(C1)) {
1224 if (ConstantFP *CFP2 = dyn_cast<ConstantFP>(C2)) {
1225 APFloat C1V = CFP1->getValueAPF();
1226 APFloat C2V = CFP2->getValueAPF();
1227 APFloat C3V = C1V; // copy for modification
1231 case Instruction::FAdd:
1232 (void)C3V.add(C2V, APFloat::rmNearestTiesToEven);
1233 return ConstantFP::get(C1->getContext(), C3V);
1234 case Instruction::FSub:
1235 (void)C3V.subtract(C2V, APFloat::rmNearestTiesToEven);
1236 return ConstantFP::get(C1->getContext(), C3V);
1237 case Instruction::FMul:
1238 (void)C3V.multiply(C2V, APFloat::rmNearestTiesToEven);
1239 return ConstantFP::get(C1->getContext(), C3V);
1240 case Instruction::FDiv:
1241 (void)C3V.divide(C2V, APFloat::rmNearestTiesToEven);
1242 return ConstantFP::get(C1->getContext(), C3V);
1243 case Instruction::FRem:
1244 (void)C3V.mod(C2V, APFloat::rmNearestTiesToEven);
1245 return ConstantFP::get(C1->getContext(), C3V);
1248 } else if (const VectorType *VTy = dyn_cast<VectorType>(C1->getType())) {
1249 ConstantVector *CP1 = dyn_cast<ConstantVector>(C1);
1250 ConstantVector *CP2 = dyn_cast<ConstantVector>(C2);
1251 if ((CP1 != NULL || isa<ConstantAggregateZero>(C1)) &&
1252 (CP2 != NULL || isa<ConstantAggregateZero>(C2))) {
1253 std::vector<Constant*> Res;
1254 const Type* EltTy = VTy->getElementType();
1260 case Instruction::Add:
1261 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1262 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1263 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1264 Res.push_back(ConstantExpr::getAdd(C1, C2));
1266 return ConstantVector::get(Res);
1267 case Instruction::FAdd:
1268 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1269 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1270 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1271 Res.push_back(ConstantExpr::getFAdd(C1, C2));
1273 return ConstantVector::get(Res);
1274 case Instruction::Sub:
1275 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1276 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1277 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1278 Res.push_back(ConstantExpr::getSub(C1, C2));
1280 return ConstantVector::get(Res);
1281 case Instruction::FSub:
1282 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1283 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1284 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1285 Res.push_back(ConstantExpr::getFSub(C1, C2));
1287 return ConstantVector::get(Res);
1288 case Instruction::Mul:
1289 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1290 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1291 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1292 Res.push_back(ConstantExpr::getMul(C1, C2));
1294 return ConstantVector::get(Res);
1295 case Instruction::FMul:
1296 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1297 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1298 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1299 Res.push_back(ConstantExpr::getFMul(C1, C2));
1301 return ConstantVector::get(Res);
1302 case Instruction::UDiv:
1303 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1304 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1305 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1306 Res.push_back(ConstantExpr::getUDiv(C1, C2));
1308 return ConstantVector::get(Res);
1309 case Instruction::SDiv:
1310 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1311 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1312 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1313 Res.push_back(ConstantExpr::getSDiv(C1, C2));
1315 return ConstantVector::get(Res);
1316 case Instruction::FDiv:
1317 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1318 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1319 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1320 Res.push_back(ConstantExpr::getFDiv(C1, C2));
1322 return ConstantVector::get(Res);
1323 case Instruction::URem:
1324 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1325 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1326 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1327 Res.push_back(ConstantExpr::getURem(C1, C2));
1329 return ConstantVector::get(Res);
1330 case Instruction::SRem:
1331 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1332 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1333 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1334 Res.push_back(ConstantExpr::getSRem(C1, C2));
1336 return ConstantVector::get(Res);
1337 case Instruction::FRem:
1338 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1339 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1340 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1341 Res.push_back(ConstantExpr::getFRem(C1, C2));
1343 return ConstantVector::get(Res);
1344 case Instruction::And:
1345 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1346 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1347 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1348 Res.push_back(ConstantExpr::getAnd(C1, C2));
1350 return ConstantVector::get(Res);
1351 case Instruction::Or:
1352 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1353 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1354 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1355 Res.push_back(ConstantExpr::getOr(C1, C2));
1357 return ConstantVector::get(Res);
1358 case Instruction::Xor:
1359 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1360 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1361 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1362 Res.push_back(ConstantExpr::getXor(C1, C2));
1364 return ConstantVector::get(Res);
1365 case Instruction::LShr:
1366 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1367 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1368 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1369 Res.push_back(ConstantExpr::getLShr(C1, C2));
1371 return ConstantVector::get(Res);
1372 case Instruction::AShr:
1373 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1374 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1375 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1376 Res.push_back(ConstantExpr::getAShr(C1, C2));
1378 return ConstantVector::get(Res);
1379 case Instruction::Shl:
1380 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1381 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1382 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1383 Res.push_back(ConstantExpr::getShl(C1, C2));
1385 return ConstantVector::get(Res);
1390 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1391 // There are many possible foldings we could do here. We should probably
1392 // at least fold add of a pointer with an integer into the appropriate
1393 // getelementptr. This will improve alias analysis a bit.
1395 // Given ((a + b) + c), if (b + c) folds to something interesting, return
1397 if (Instruction::isAssociative(Opcode) && CE1->getOpcode() == Opcode) {
1398 Constant *T = ConstantExpr::get(Opcode, CE1->getOperand(1), C2);
1399 if (!isa<ConstantExpr>(T) || cast<ConstantExpr>(T)->getOpcode() != Opcode)
1400 return ConstantExpr::get(Opcode, CE1->getOperand(0), T);
1402 } else if (isa<ConstantExpr>(C2)) {
1403 // If C2 is a constant expr and C1 isn't, flop them around and fold the
1404 // other way if possible.
1405 if (Instruction::isCommutative(Opcode))
1406 return ConstantFoldBinaryInstruction(Opcode, C2, C1);
1409 // i1 can be simplified in many cases.
1410 if (C1->getType()->isIntegerTy(1)) {
1412 case Instruction::Add:
1413 case Instruction::Sub:
1414 return ConstantExpr::getXor(C1, C2);
1415 case Instruction::Mul:
1416 return ConstantExpr::getAnd(C1, C2);
1417 case Instruction::Shl:
1418 case Instruction::LShr:
1419 case Instruction::AShr:
1420 // We can assume that C2 == 0. If it were one the result would be
1421 // undefined because the shift value is as large as the bitwidth.
1423 case Instruction::SDiv:
1424 case Instruction::UDiv:
1425 // We can assume that C2 == 1. If it were zero the result would be
1426 // undefined through division by zero.
1428 case Instruction::URem:
1429 case Instruction::SRem:
1430 // We can assume that C2 == 1. If it were zero the result would be
1431 // undefined through division by zero.
1432 return ConstantInt::getFalse(C1->getContext());
1438 // We don't know how to fold this.
1442 /// isZeroSizedType - This type is zero sized if its an array or structure of
1443 /// zero sized types. The only leaf zero sized type is an empty structure.
1444 static bool isMaybeZeroSizedType(const Type *Ty) {
1445 if (Ty->isOpaqueTy()) return true; // Can't say.
1446 if (const StructType *STy = dyn_cast<StructType>(Ty)) {
1448 // If all of elements have zero size, this does too.
1449 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
1450 if (!isMaybeZeroSizedType(STy->getElementType(i))) return false;
1453 } else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
1454 return isMaybeZeroSizedType(ATy->getElementType());
1459 /// IdxCompare - Compare the two constants as though they were getelementptr
1460 /// indices. This allows coersion of the types to be the same thing.
1462 /// If the two constants are the "same" (after coersion), return 0. If the
1463 /// first is less than the second, return -1, if the second is less than the
1464 /// first, return 1. If the constants are not integral, return -2.
1466 static int IdxCompare(Constant *C1, Constant *C2, const Type *ElTy) {
1467 if (C1 == C2) return 0;
1469 // Ok, we found a different index. If they are not ConstantInt, we can't do
1470 // anything with them.
1471 if (!isa<ConstantInt>(C1) || !isa<ConstantInt>(C2))
1472 return -2; // don't know!
1474 // Ok, we have two differing integer indices. Sign extend them to be the same
1475 // type. Long is always big enough, so we use it.
1476 if (!C1->getType()->isIntegerTy(64))
1477 C1 = ConstantExpr::getSExt(C1, Type::getInt64Ty(C1->getContext()));
1479 if (!C2->getType()->isIntegerTy(64))
1480 C2 = ConstantExpr::getSExt(C2, Type::getInt64Ty(C1->getContext()));
1482 if (C1 == C2) return 0; // They are equal
1484 // If the type being indexed over is really just a zero sized type, there is
1485 // no pointer difference being made here.
1486 if (isMaybeZeroSizedType(ElTy))
1487 return -2; // dunno.
1489 // If they are really different, now that they are the same type, then we
1490 // found a difference!
1491 if (cast<ConstantInt>(C1)->getSExtValue() <
1492 cast<ConstantInt>(C2)->getSExtValue())
1498 /// evaluateFCmpRelation - This function determines if there is anything we can
1499 /// decide about the two constants provided. This doesn't need to handle simple
1500 /// things like ConstantFP comparisons, but should instead handle ConstantExprs.
1501 /// If we can determine that the two constants have a particular relation to
1502 /// each other, we should return the corresponding FCmpInst predicate,
1503 /// otherwise return FCmpInst::BAD_FCMP_PREDICATE. This is used below in
1504 /// ConstantFoldCompareInstruction.
1506 /// To simplify this code we canonicalize the relation so that the first
1507 /// operand is always the most "complex" of the two. We consider ConstantFP
1508 /// to be the simplest, and ConstantExprs to be the most complex.
1509 static FCmpInst::Predicate evaluateFCmpRelation(Constant *V1, Constant *V2) {
1510 assert(V1->getType() == V2->getType() &&
1511 "Cannot compare values of different types!");
1513 // No compile-time operations on this type yet.
1514 if (V1->getType()->isPPC_FP128Ty())
1515 return FCmpInst::BAD_FCMP_PREDICATE;
1517 // Handle degenerate case quickly
1518 if (V1 == V2) return FCmpInst::FCMP_OEQ;
1520 if (!isa<ConstantExpr>(V1)) {
1521 if (!isa<ConstantExpr>(V2)) {
1522 // We distilled thisUse the standard constant folder for a few cases
1524 R = dyn_cast<ConstantInt>(
1525 ConstantExpr::getFCmp(FCmpInst::FCMP_OEQ, V1, V2));
1526 if (R && !R->isZero())
1527 return FCmpInst::FCMP_OEQ;
1528 R = dyn_cast<ConstantInt>(
1529 ConstantExpr::getFCmp(FCmpInst::FCMP_OLT, V1, V2));
1530 if (R && !R->isZero())
1531 return FCmpInst::FCMP_OLT;
1532 R = dyn_cast<ConstantInt>(
1533 ConstantExpr::getFCmp(FCmpInst::FCMP_OGT, V1, V2));
1534 if (R && !R->isZero())
1535 return FCmpInst::FCMP_OGT;
1537 // Nothing more we can do
1538 return FCmpInst::BAD_FCMP_PREDICATE;
1541 // If the first operand is simple and second is ConstantExpr, swap operands.
1542 FCmpInst::Predicate SwappedRelation = evaluateFCmpRelation(V2, V1);
1543 if (SwappedRelation != FCmpInst::BAD_FCMP_PREDICATE)
1544 return FCmpInst::getSwappedPredicate(SwappedRelation);
1546 // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1547 // constantexpr or a simple constant.
1548 ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1549 switch (CE1->getOpcode()) {
1550 case Instruction::FPTrunc:
1551 case Instruction::FPExt:
1552 case Instruction::UIToFP:
1553 case Instruction::SIToFP:
1554 // We might be able to do something with these but we don't right now.
1560 // There are MANY other foldings that we could perform here. They will
1561 // probably be added on demand, as they seem needed.
1562 return FCmpInst::BAD_FCMP_PREDICATE;
1565 /// evaluateICmpRelation - This function determines if there is anything we can
1566 /// decide about the two constants provided. This doesn't need to handle simple
1567 /// things like integer comparisons, but should instead handle ConstantExprs
1568 /// and GlobalValues. If we can determine that the two constants have a
1569 /// particular relation to each other, we should return the corresponding ICmp
1570 /// predicate, otherwise return ICmpInst::BAD_ICMP_PREDICATE.
1572 /// To simplify this code we canonicalize the relation so that the first
1573 /// operand is always the most "complex" of the two. We consider simple
1574 /// constants (like ConstantInt) to be the simplest, followed by
1575 /// GlobalValues, followed by ConstantExpr's (the most complex).
1577 static ICmpInst::Predicate evaluateICmpRelation(Constant *V1, Constant *V2,
1579 assert(V1->getType() == V2->getType() &&
1580 "Cannot compare different types of values!");
1581 if (V1 == V2) return ICmpInst::ICMP_EQ;
1583 if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1) &&
1584 !isa<BlockAddress>(V1)) {
1585 if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2) &&
1586 !isa<BlockAddress>(V2)) {
1587 // We distilled this down to a simple case, use the standard constant
1590 ICmpInst::Predicate pred = ICmpInst::ICMP_EQ;
1591 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1592 if (R && !R->isZero())
1594 pred = isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1595 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1596 if (R && !R->isZero())
1598 pred = isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1599 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1600 if (R && !R->isZero())
1603 // If we couldn't figure it out, bail.
1604 return ICmpInst::BAD_ICMP_PREDICATE;
1607 // If the first operand is simple, swap operands.
1608 ICmpInst::Predicate SwappedRelation =
1609 evaluateICmpRelation(V2, V1, isSigned);
1610 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1611 return ICmpInst::getSwappedPredicate(SwappedRelation);
1613 } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1)) {
1614 if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1615 ICmpInst::Predicate SwappedRelation =
1616 evaluateICmpRelation(V2, V1, isSigned);
1617 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1618 return ICmpInst::getSwappedPredicate(SwappedRelation);
1619 return ICmpInst::BAD_ICMP_PREDICATE;
1622 // Now we know that the RHS is a GlobalValue, BlockAddress or simple
1623 // constant (which, since the types must match, means that it's a
1624 // ConstantPointerNull).
1625 if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
1626 // Don't try to decide equality of aliases.
1627 if (!isa<GlobalAlias>(GV) && !isa<GlobalAlias>(GV2))
1628 if (!GV->hasExternalWeakLinkage() || !GV2->hasExternalWeakLinkage())
1629 return ICmpInst::ICMP_NE;
1630 } else if (isa<BlockAddress>(V2)) {
1631 return ICmpInst::ICMP_NE; // Globals never equal labels.
1633 assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!");
1634 // GlobalVals can never be null unless they have external weak linkage.
1635 // We don't try to evaluate aliases here.
1636 if (!GV->hasExternalWeakLinkage() && !isa<GlobalAlias>(GV))
1637 return ICmpInst::ICMP_NE;
1639 } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(V1)) {
1640 if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1641 ICmpInst::Predicate SwappedRelation =
1642 evaluateICmpRelation(V2, V1, isSigned);
1643 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1644 return ICmpInst::getSwappedPredicate(SwappedRelation);
1645 return ICmpInst::BAD_ICMP_PREDICATE;
1648 // Now we know that the RHS is a GlobalValue, BlockAddress or simple
1649 // constant (which, since the types must match, means that it is a
1650 // ConstantPointerNull).
1651 if (const BlockAddress *BA2 = dyn_cast<BlockAddress>(V2)) {
1652 // Block address in another function can't equal this one, but block
1653 // addresses in the current function might be the same if blocks are
1655 if (BA2->getFunction() != BA->getFunction())
1656 return ICmpInst::ICMP_NE;
1658 // Block addresses aren't null, don't equal the address of globals.
1659 assert((isa<ConstantPointerNull>(V2) || isa<GlobalValue>(V2)) &&
1660 "Canonicalization guarantee!");
1661 return ICmpInst::ICMP_NE;
1664 // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1665 // constantexpr, a global, block address, or a simple constant.
1666 ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1667 Constant *CE1Op0 = CE1->getOperand(0);
1669 switch (CE1->getOpcode()) {
1670 case Instruction::Trunc:
1671 case Instruction::FPTrunc:
1672 case Instruction::FPExt:
1673 case Instruction::FPToUI:
1674 case Instruction::FPToSI:
1675 break; // We can't evaluate floating point casts or truncations.
1677 case Instruction::UIToFP:
1678 case Instruction::SIToFP:
1679 case Instruction::BitCast:
1680 case Instruction::ZExt:
1681 case Instruction::SExt:
1682 // If the cast is not actually changing bits, and the second operand is a
1683 // null pointer, do the comparison with the pre-casted value.
1684 if (V2->isNullValue() &&
1685 (CE1->getType()->isPointerTy() || CE1->getType()->isIntegerTy())) {
1686 if (CE1->getOpcode() == Instruction::ZExt) isSigned = false;
1687 if (CE1->getOpcode() == Instruction::SExt) isSigned = true;
1688 return evaluateICmpRelation(CE1Op0,
1689 Constant::getNullValue(CE1Op0->getType()),
1694 case Instruction::GetElementPtr:
1695 // Ok, since this is a getelementptr, we know that the constant has a
1696 // pointer type. Check the various cases.
1697 if (isa<ConstantPointerNull>(V2)) {
1698 // If we are comparing a GEP to a null pointer, check to see if the base
1699 // of the GEP equals the null pointer.
1700 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1701 if (GV->hasExternalWeakLinkage())
1702 // Weak linkage GVals could be zero or not. We're comparing that
1703 // to null pointer so its greater-or-equal
1704 return isSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE;
1706 // If its not weak linkage, the GVal must have a non-zero address
1707 // so the result is greater-than
1708 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1709 } else if (isa<ConstantPointerNull>(CE1Op0)) {
1710 // If we are indexing from a null pointer, check to see if we have any
1711 // non-zero indices.
1712 for (unsigned i = 1, e = CE1->getNumOperands(); i != e; ++i)
1713 if (!CE1->getOperand(i)->isNullValue())
1714 // Offsetting from null, must not be equal.
1715 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1716 // Only zero indexes from null, must still be zero.
1717 return ICmpInst::ICMP_EQ;
1719 // Otherwise, we can't really say if the first operand is null or not.
1720 } else if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
1721 if (isa<ConstantPointerNull>(CE1Op0)) {
1722 if (GV2->hasExternalWeakLinkage())
1723 // Weak linkage GVals could be zero or not. We're comparing it to
1724 // a null pointer, so its less-or-equal
1725 return isSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE;
1727 // If its not weak linkage, the GVal must have a non-zero address
1728 // so the result is less-than
1729 return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1730 } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1732 // If this is a getelementptr of the same global, then it must be
1733 // different. Because the types must match, the getelementptr could
1734 // only have at most one index, and because we fold getelementptr's
1735 // with a single zero index, it must be nonzero.
1736 assert(CE1->getNumOperands() == 2 &&
1737 !CE1->getOperand(1)->isNullValue() &&
1738 "Suprising getelementptr!");
1739 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1741 // If they are different globals, we don't know what the value is,
1742 // but they can't be equal.
1743 return ICmpInst::ICMP_NE;
1747 ConstantExpr *CE2 = cast<ConstantExpr>(V2);
1748 Constant *CE2Op0 = CE2->getOperand(0);
1750 // There are MANY other foldings that we could perform here. They will
1751 // probably be added on demand, as they seem needed.
1752 switch (CE2->getOpcode()) {
1754 case Instruction::GetElementPtr:
1755 // By far the most common case to handle is when the base pointers are
1756 // obviously to the same or different globals.
1757 if (isa<GlobalValue>(CE1Op0) && isa<GlobalValue>(CE2Op0)) {
1758 if (CE1Op0 != CE2Op0) // Don't know relative ordering, but not equal
1759 return ICmpInst::ICMP_NE;
1760 // Ok, we know that both getelementptr instructions are based on the
1761 // same global. From this, we can precisely determine the relative
1762 // ordering of the resultant pointers.
1765 // The logic below assumes that the result of the comparison
1766 // can be determined by finding the first index that differs.
1767 // This doesn't work if there is over-indexing in any
1768 // subsequent indices, so check for that case first.
1769 if (!CE1->isGEPWithNoNotionalOverIndexing() ||
1770 !CE2->isGEPWithNoNotionalOverIndexing())
1771 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1773 // Compare all of the operands the GEP's have in common.
1774 gep_type_iterator GTI = gep_type_begin(CE1);
1775 for (;i != CE1->getNumOperands() && i != CE2->getNumOperands();
1777 switch (IdxCompare(CE1->getOperand(i),
1778 CE2->getOperand(i), GTI.getIndexedType())) {
1779 case -1: return isSigned ? ICmpInst::ICMP_SLT:ICmpInst::ICMP_ULT;
1780 case 1: return isSigned ? ICmpInst::ICMP_SGT:ICmpInst::ICMP_UGT;
1781 case -2: return ICmpInst::BAD_ICMP_PREDICATE;
1784 // Ok, we ran out of things they have in common. If any leftovers
1785 // are non-zero then we have a difference, otherwise we are equal.
1786 for (; i < CE1->getNumOperands(); ++i)
1787 if (!CE1->getOperand(i)->isNullValue()) {
1788 if (isa<ConstantInt>(CE1->getOperand(i)))
1789 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1791 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1794 for (; i < CE2->getNumOperands(); ++i)
1795 if (!CE2->getOperand(i)->isNullValue()) {
1796 if (isa<ConstantInt>(CE2->getOperand(i)))
1797 return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1799 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1801 return ICmpInst::ICMP_EQ;
1810 return ICmpInst::BAD_ICMP_PREDICATE;
1813 Constant *llvm::ConstantFoldCompareInstruction(unsigned short pred,
1814 Constant *C1, Constant *C2) {
1815 const Type *ResultTy;
1816 if (const VectorType *VT = dyn_cast<VectorType>(C1->getType()))
1817 ResultTy = VectorType::get(Type::getInt1Ty(C1->getContext()),
1818 VT->getNumElements());
1820 ResultTy = Type::getInt1Ty(C1->getContext());
1822 // Fold FCMP_FALSE/FCMP_TRUE unconditionally.
1823 if (pred == FCmpInst::FCMP_FALSE)
1824 return Constant::getNullValue(ResultTy);
1826 if (pred == FCmpInst::FCMP_TRUE)
1827 return Constant::getAllOnesValue(ResultTy);
1829 // Handle some degenerate cases first
1830 if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
1831 // For EQ and NE, we can always pick a value for the undef to make the
1832 // predicate pass or fail, so we can return undef.
1833 if (ICmpInst::isEquality(ICmpInst::Predicate(pred)))
1834 return UndefValue::get(ResultTy);
1835 // Otherwise, pick the same value as the non-undef operand, and fold
1836 // it to true or false.
1837 return ConstantInt::get(ResultTy, CmpInst::isTrueWhenEqual(pred));
1840 // No compile-time operations on this type yet.
1841 if (C1->getType()->isPPC_FP128Ty())
1844 // icmp eq/ne(null,GV) -> false/true
1845 if (C1->isNullValue()) {
1846 if (const GlobalValue *GV = dyn_cast<GlobalValue>(C2))
1847 // Don't try to evaluate aliases. External weak GV can be null.
1848 if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
1849 if (pred == ICmpInst::ICMP_EQ)
1850 return ConstantInt::getFalse(C1->getContext());
1851 else if (pred == ICmpInst::ICMP_NE)
1852 return ConstantInt::getTrue(C1->getContext());
1854 // icmp eq/ne(GV,null) -> false/true
1855 } else if (C2->isNullValue()) {
1856 if (const GlobalValue *GV = dyn_cast<GlobalValue>(C1))
1857 // Don't try to evaluate aliases. External weak GV can be null.
1858 if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
1859 if (pred == ICmpInst::ICMP_EQ)
1860 return ConstantInt::getFalse(C1->getContext());
1861 else if (pred == ICmpInst::ICMP_NE)
1862 return ConstantInt::getTrue(C1->getContext());
1866 // If the comparison is a comparison between two i1's, simplify it.
1867 if (C1->getType()->isIntegerTy(1)) {
1869 case ICmpInst::ICMP_EQ:
1870 if (isa<ConstantInt>(C2))
1871 return ConstantExpr::getXor(C1, ConstantExpr::getNot(C2));
1872 return ConstantExpr::getXor(ConstantExpr::getNot(C1), C2);
1873 case ICmpInst::ICMP_NE:
1874 return ConstantExpr::getXor(C1, C2);
1880 if (isa<ConstantInt>(C1) && isa<ConstantInt>(C2)) {
1881 APInt V1 = cast<ConstantInt>(C1)->getValue();
1882 APInt V2 = cast<ConstantInt>(C2)->getValue();
1884 default: llvm_unreachable("Invalid ICmp Predicate"); return 0;
1885 case ICmpInst::ICMP_EQ: return ConstantInt::get(ResultTy, V1 == V2);
1886 case ICmpInst::ICMP_NE: return ConstantInt::get(ResultTy, V1 != V2);
1887 case ICmpInst::ICMP_SLT: return ConstantInt::get(ResultTy, V1.slt(V2));
1888 case ICmpInst::ICMP_SGT: return ConstantInt::get(ResultTy, V1.sgt(V2));
1889 case ICmpInst::ICMP_SLE: return ConstantInt::get(ResultTy, V1.sle(V2));
1890 case ICmpInst::ICMP_SGE: return ConstantInt::get(ResultTy, V1.sge(V2));
1891 case ICmpInst::ICMP_ULT: return ConstantInt::get(ResultTy, V1.ult(V2));
1892 case ICmpInst::ICMP_UGT: return ConstantInt::get(ResultTy, V1.ugt(V2));
1893 case ICmpInst::ICMP_ULE: return ConstantInt::get(ResultTy, V1.ule(V2));
1894 case ICmpInst::ICMP_UGE: return ConstantInt::get(ResultTy, V1.uge(V2));
1896 } else if (isa<ConstantFP>(C1) && isa<ConstantFP>(C2)) {
1897 APFloat C1V = cast<ConstantFP>(C1)->getValueAPF();
1898 APFloat C2V = cast<ConstantFP>(C2)->getValueAPF();
1899 APFloat::cmpResult R = C1V.compare(C2V);
1901 default: llvm_unreachable("Invalid FCmp Predicate"); return 0;
1902 case FCmpInst::FCMP_FALSE: return Constant::getNullValue(ResultTy);
1903 case FCmpInst::FCMP_TRUE: return Constant::getAllOnesValue(ResultTy);
1904 case FCmpInst::FCMP_UNO:
1905 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered);
1906 case FCmpInst::FCMP_ORD:
1907 return ConstantInt::get(ResultTy, R!=APFloat::cmpUnordered);
1908 case FCmpInst::FCMP_UEQ:
1909 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1910 R==APFloat::cmpEqual);
1911 case FCmpInst::FCMP_OEQ:
1912 return ConstantInt::get(ResultTy, R==APFloat::cmpEqual);
1913 case FCmpInst::FCMP_UNE:
1914 return ConstantInt::get(ResultTy, R!=APFloat::cmpEqual);
1915 case FCmpInst::FCMP_ONE:
1916 return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
1917 R==APFloat::cmpGreaterThan);
1918 case FCmpInst::FCMP_ULT:
1919 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1920 R==APFloat::cmpLessThan);
1921 case FCmpInst::FCMP_OLT:
1922 return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan);
1923 case FCmpInst::FCMP_UGT:
1924 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1925 R==APFloat::cmpGreaterThan);
1926 case FCmpInst::FCMP_OGT:
1927 return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan);
1928 case FCmpInst::FCMP_ULE:
1929 return ConstantInt::get(ResultTy, R!=APFloat::cmpGreaterThan);
1930 case FCmpInst::FCMP_OLE:
1931 return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
1932 R==APFloat::cmpEqual);
1933 case FCmpInst::FCMP_UGE:
1934 return ConstantInt::get(ResultTy, R!=APFloat::cmpLessThan);
1935 case FCmpInst::FCMP_OGE:
1936 return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan ||
1937 R==APFloat::cmpEqual);
1939 } else if (C1->getType()->isVectorTy()) {
1940 SmallVector<Constant*, 16> C1Elts, C2Elts;
1941 C1->getVectorElements(C1Elts);
1942 C2->getVectorElements(C2Elts);
1943 if (C1Elts.empty() || C2Elts.empty())
1946 // If we can constant fold the comparison of each element, constant fold
1947 // the whole vector comparison.
1948 SmallVector<Constant*, 4> ResElts;
1949 // Compare the elements, producing an i1 result or constant expr.
1950 for (unsigned i = 0, e = C1Elts.size(); i != e; ++i)
1951 ResElts.push_back(ConstantExpr::getCompare(pred, C1Elts[i], C2Elts[i]));
1953 return ConstantVector::get(ResElts);
1956 if (C1->getType()->isFloatingPointTy()) {
1957 int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
1958 switch (evaluateFCmpRelation(C1, C2)) {
1959 default: llvm_unreachable("Unknown relation!");
1960 case FCmpInst::FCMP_UNO:
1961 case FCmpInst::FCMP_ORD:
1962 case FCmpInst::FCMP_UEQ:
1963 case FCmpInst::FCMP_UNE:
1964 case FCmpInst::FCMP_ULT:
1965 case FCmpInst::FCMP_UGT:
1966 case FCmpInst::FCMP_ULE:
1967 case FCmpInst::FCMP_UGE:
1968 case FCmpInst::FCMP_TRUE:
1969 case FCmpInst::FCMP_FALSE:
1970 case FCmpInst::BAD_FCMP_PREDICATE:
1971 break; // Couldn't determine anything about these constants.
1972 case FCmpInst::FCMP_OEQ: // We know that C1 == C2
1973 Result = (pred == FCmpInst::FCMP_UEQ || pred == FCmpInst::FCMP_OEQ ||
1974 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE ||
1975 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
1977 case FCmpInst::FCMP_OLT: // We know that C1 < C2
1978 Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
1979 pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT ||
1980 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE);
1982 case FCmpInst::FCMP_OGT: // We know that C1 > C2
1983 Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
1984 pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT ||
1985 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
1987 case FCmpInst::FCMP_OLE: // We know that C1 <= C2
1988 // We can only partially decide this relation.
1989 if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
1991 else if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
1994 case FCmpInst::FCMP_OGE: // We known that C1 >= C2
1995 // We can only partially decide this relation.
1996 if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
1998 else if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
2001 case FCmpInst::FCMP_ONE: // We know that C1 != C2
2002 // We can only partially decide this relation.
2003 if (pred == FCmpInst::FCMP_OEQ || pred == FCmpInst::FCMP_UEQ)
2005 else if (pred == FCmpInst::FCMP_ONE || pred == FCmpInst::FCMP_UNE)
2010 // If we evaluated the result, return it now.
2012 return ConstantInt::get(ResultTy, Result);
2015 // Evaluate the relation between the two constants, per the predicate.
2016 int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
2017 switch (evaluateICmpRelation(C1, C2, CmpInst::isSigned(pred))) {
2018 default: llvm_unreachable("Unknown relational!");
2019 case ICmpInst::BAD_ICMP_PREDICATE:
2020 break; // Couldn't determine anything about these constants.
2021 case ICmpInst::ICMP_EQ: // We know the constants are equal!
2022 // If we know the constants are equal, we can decide the result of this
2023 // computation precisely.
2024 Result = ICmpInst::isTrueWhenEqual((ICmpInst::Predicate)pred);
2026 case ICmpInst::ICMP_ULT:
2028 case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_ULE:
2030 case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_UGE:
2034 case ICmpInst::ICMP_SLT:
2036 case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SLE:
2038 case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SGE:
2042 case ICmpInst::ICMP_UGT:
2044 case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_UGE:
2046 case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_ULE:
2050 case ICmpInst::ICMP_SGT:
2052 case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SGE:
2054 case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SLE:
2058 case ICmpInst::ICMP_ULE:
2059 if (pred == ICmpInst::ICMP_UGT) Result = 0;
2060 if (pred == ICmpInst::ICMP_ULT || pred == ICmpInst::ICMP_ULE) Result = 1;
2062 case ICmpInst::ICMP_SLE:
2063 if (pred == ICmpInst::ICMP_SGT) Result = 0;
2064 if (pred == ICmpInst::ICMP_SLT || pred == ICmpInst::ICMP_SLE) Result = 1;
2066 case ICmpInst::ICMP_UGE:
2067 if (pred == ICmpInst::ICMP_ULT) Result = 0;
2068 if (pred == ICmpInst::ICMP_UGT || pred == ICmpInst::ICMP_UGE) Result = 1;
2070 case ICmpInst::ICMP_SGE:
2071 if (pred == ICmpInst::ICMP_SLT) Result = 0;
2072 if (pred == ICmpInst::ICMP_SGT || pred == ICmpInst::ICMP_SGE) Result = 1;
2074 case ICmpInst::ICMP_NE:
2075 if (pred == ICmpInst::ICMP_EQ) Result = 0;
2076 if (pred == ICmpInst::ICMP_NE) Result = 1;
2080 // If we evaluated the result, return it now.
2082 return ConstantInt::get(ResultTy, Result);
2084 // If the right hand side is a bitcast, try using its inverse to simplify
2085 // it by moving it to the left hand side. We can't do this if it would turn
2086 // a vector compare into a scalar compare or visa versa.
2087 if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(C2)) {
2088 Constant *CE2Op0 = CE2->getOperand(0);
2089 if (CE2->getOpcode() == Instruction::BitCast &&
2090 CE2->getType()->isVectorTy() == CE2Op0->getType()->isVectorTy()) {
2091 Constant *Inverse = ConstantExpr::getBitCast(C1, CE2Op0->getType());
2092 return ConstantExpr::getICmp(pred, Inverse, CE2Op0);
2096 // If the left hand side is an extension, try eliminating it.
2097 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
2098 if ((CE1->getOpcode() == Instruction::SExt && ICmpInst::isSigned(pred)) ||
2099 (CE1->getOpcode() == Instruction::ZExt && !ICmpInst::isSigned(pred))){
2100 Constant *CE1Op0 = CE1->getOperand(0);
2101 Constant *CE1Inverse = ConstantExpr::getTrunc(CE1, CE1Op0->getType());
2102 if (CE1Inverse == CE1Op0) {
2103 // Check whether we can safely truncate the right hand side.
2104 Constant *C2Inverse = ConstantExpr::getTrunc(C2, CE1Op0->getType());
2105 if (ConstantExpr::getZExt(C2Inverse, C2->getType()) == C2) {
2106 return ConstantExpr::getICmp(pred, CE1Inverse, C2Inverse);
2112 if ((!isa<ConstantExpr>(C1) && isa<ConstantExpr>(C2)) ||
2113 (C1->isNullValue() && !C2->isNullValue())) {
2114 // If C2 is a constant expr and C1 isn't, flip them around and fold the
2115 // other way if possible.
2116 // Also, if C1 is null and C2 isn't, flip them around.
2117 pred = ICmpInst::getSwappedPredicate((ICmpInst::Predicate)pred);
2118 return ConstantExpr::getICmp(pred, C2, C1);
2124 /// isInBoundsIndices - Test whether the given sequence of *normalized* indices
2126 template<typename IndexTy>
2127 static bool isInBoundsIndices(IndexTy const *Idxs, size_t NumIdx) {
2128 // No indices means nothing that could be out of bounds.
2129 if (NumIdx == 0) return true;
2131 // If the first index is zero, it's in bounds.
2132 if (cast<Constant>(Idxs[0])->isNullValue()) return true;
2134 // If the first index is one and all the rest are zero, it's in bounds,
2135 // by the one-past-the-end rule.
2136 if (!cast<ConstantInt>(Idxs[0])->isOne())
2138 for (unsigned i = 1, e = NumIdx; i != e; ++i)
2139 if (!cast<Constant>(Idxs[i])->isNullValue())
2144 template<typename IndexTy>
2145 static Constant *ConstantFoldGetElementPtrImpl(Constant *C,
2147 IndexTy const *Idxs,
2149 Constant *Idx0 = cast<Constant>(Idxs[0]);
2151 (NumIdx == 1 && Idx0->isNullValue()))
2154 if (isa<UndefValue>(C)) {
2155 const PointerType *Ptr = cast<PointerType>(C->getType());
2156 const Type *Ty = GetElementPtrInst::getIndexedType(Ptr, Idxs, Idxs+NumIdx);
2157 assert(Ty != 0 && "Invalid indices for GEP!");
2158 return UndefValue::get(PointerType::get(Ty, Ptr->getAddressSpace()));
2161 if (C->isNullValue()) {
2163 for (unsigned i = 0, e = NumIdx; i != e; ++i)
2164 if (!cast<Constant>(Idxs[i])->isNullValue()) {
2169 const PointerType *Ptr = cast<PointerType>(C->getType());
2170 const Type *Ty = GetElementPtrInst::getIndexedType(Ptr, Idxs,
2172 assert(Ty != 0 && "Invalid indices for GEP!");
2173 return ConstantPointerNull::get(PointerType::get(Ty,
2174 Ptr->getAddressSpace()));
2178 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2179 // Combine Indices - If the source pointer to this getelementptr instruction
2180 // is a getelementptr instruction, combine the indices of the two
2181 // getelementptr instructions into a single instruction.
2183 if (CE->getOpcode() == Instruction::GetElementPtr) {
2184 const Type *LastTy = 0;
2185 for (gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
2189 if ((LastTy && LastTy->isArrayTy()) || Idx0->isNullValue()) {
2190 SmallVector<Value*, 16> NewIndices;
2191 NewIndices.reserve(NumIdx + CE->getNumOperands());
2192 for (unsigned i = 1, e = CE->getNumOperands()-1; i != e; ++i)
2193 NewIndices.push_back(CE->getOperand(i));
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 const Type *IdxTy = Combined->getType();
2201 if (IdxTy != Idx0->getType()) {
2202 const Type *Int64Ty = Type::getInt64Ty(IdxTy->getContext());
2203 Constant *C1 = ConstantExpr::getSExtOrBitCast(Idx0, Int64Ty);
2204 Constant *C2 = ConstantExpr::getSExtOrBitCast(Combined, Int64Ty);
2205 Combined = ConstantExpr::get(Instruction::Add, C1, C2);
2208 ConstantExpr::get(Instruction::Add, Idx0, Combined);
2212 NewIndices.push_back(Combined);
2213 NewIndices.append(Idxs+1, Idxs+NumIdx);
2214 return (inBounds && cast<GEPOperator>(CE)->isInBounds()) ?
2215 ConstantExpr::getInBoundsGetElementPtr(CE->getOperand(0),
2217 NewIndices.size()) :
2218 ConstantExpr::getGetElementPtr(CE->getOperand(0),
2224 // Implement folding of:
2225 // i32* getelementptr ([2 x i32]* bitcast ([3 x i32]* %X to [2 x i32]*),
2227 // To: i32* getelementptr ([3 x i32]* %X, i64 0, i64 0)
2229 if (CE->isCast() && NumIdx > 1 && Idx0->isNullValue()) {
2230 if (const PointerType *SPT =
2231 dyn_cast<PointerType>(CE->getOperand(0)->getType()))
2232 if (const ArrayType *SAT = dyn_cast<ArrayType>(SPT->getElementType()))
2233 if (const ArrayType *CAT =
2234 dyn_cast<ArrayType>(cast<PointerType>(C->getType())->getElementType()))
2235 if (CAT->getElementType() == SAT->getElementType())
2237 ConstantExpr::getInBoundsGetElementPtr(
2238 (Constant*)CE->getOperand(0), Idxs, NumIdx) :
2239 ConstantExpr::getGetElementPtr(
2240 (Constant*)CE->getOperand(0), Idxs, NumIdx);
2244 // Check to see if any array indices are not within the corresponding
2245 // notional array bounds. If so, try to determine if they can be factored
2246 // out into preceding dimensions.
2247 bool Unknown = false;
2248 SmallVector<Constant *, 8> NewIdxs;
2249 const Type *Ty = C->getType();
2250 const Type *Prev = 0;
2251 for (unsigned i = 0; i != NumIdx;
2252 Prev = Ty, Ty = cast<CompositeType>(Ty)->getTypeAtIndex(Idxs[i]), ++i) {
2253 if (ConstantInt *CI = dyn_cast<ConstantInt>(Idxs[i])) {
2254 if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty))
2255 if (ATy->getNumElements() <= INT64_MAX &&
2256 ATy->getNumElements() != 0 &&
2257 CI->getSExtValue() >= (int64_t)ATy->getNumElements()) {
2258 if (isa<SequentialType>(Prev)) {
2259 // It's out of range, but we can factor it into the prior
2261 NewIdxs.resize(NumIdx);
2262 ConstantInt *Factor = ConstantInt::get(CI->getType(),
2263 ATy->getNumElements());
2264 NewIdxs[i] = ConstantExpr::getSRem(CI, Factor);
2266 Constant *PrevIdx = cast<Constant>(Idxs[i-1]);
2267 Constant *Div = ConstantExpr::getSDiv(CI, Factor);
2269 // Before adding, extend both operands to i64 to avoid
2270 // overflow trouble.
2271 if (!PrevIdx->getType()->isIntegerTy(64))
2272 PrevIdx = ConstantExpr::getSExt(PrevIdx,
2273 Type::getInt64Ty(Div->getContext()));
2274 if (!Div->getType()->isIntegerTy(64))
2275 Div = ConstantExpr::getSExt(Div,
2276 Type::getInt64Ty(Div->getContext()));
2278 NewIdxs[i-1] = ConstantExpr::getAdd(PrevIdx, Div);
2280 // It's out of range, but the prior dimension is a struct
2281 // so we can't do anything about it.
2286 // We don't know if it's in range or not.
2291 // If we did any factoring, start over with the adjusted indices.
2292 if (!NewIdxs.empty()) {
2293 for (unsigned i = 0; i != NumIdx; ++i)
2294 if (!NewIdxs[i]) NewIdxs[i] = cast<Constant>(Idxs[i]);
2296 ConstantExpr::getInBoundsGetElementPtr(C, NewIdxs.data(),
2298 ConstantExpr::getGetElementPtr(C, NewIdxs.data(), NewIdxs.size());
2301 // If all indices are known integers and normalized, we can do a simple
2302 // check for the "inbounds" property.
2303 if (!Unknown && !inBounds &&
2304 isa<GlobalVariable>(C) && isInBoundsIndices(Idxs, NumIdx))
2305 return ConstantExpr::getInBoundsGetElementPtr(C, Idxs, NumIdx);
2310 Constant *llvm::ConstantFoldGetElementPtr(Constant *C,
2312 Constant* const *Idxs,
2314 return ConstantFoldGetElementPtrImpl(C, inBounds, Idxs, NumIdx);
2317 Constant *llvm::ConstantFoldGetElementPtr(Constant *C,
2321 return ConstantFoldGetElementPtrImpl(C, inBounds, Idxs, NumIdx);