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/Operator.h"
28 #include "llvm/ADT/SmallVector.h"
29 #include "llvm/Support/Compiler.h"
30 #include "llvm/Support/ErrorHandling.h"
31 #include "llvm/Support/GetElementPtrTypeIterator.h"
32 #include "llvm/Support/ManagedStatic.h"
33 #include "llvm/Support/MathExtras.h"
37 //===----------------------------------------------------------------------===//
38 // ConstantFold*Instruction Implementations
39 //===----------------------------------------------------------------------===//
41 /// BitCastConstantVector - Convert the specified ConstantVector node to the
42 /// specified vector type. At this point, we know that the elements of the
43 /// input vector constant are all simple integer or FP values.
44 static Constant *BitCastConstantVector(ConstantVector *CV,
47 if (CV->isAllOnesValue()) return Constant::getAllOnesValue(DstTy);
48 if (CV->isNullValue()) return Constant::getNullValue(DstTy);
50 // If this cast changes element count then we can't handle it here:
51 // doing so requires endianness information. This should be handled by
52 // Analysis/ConstantFolding.cpp
53 unsigned NumElts = DstTy->getNumElements();
54 if (NumElts != CV->getNumOperands())
57 // Check to verify that all elements of the input are simple.
58 for (unsigned i = 0; i != NumElts; ++i) {
59 if (!isa<ConstantInt>(CV->getOperand(i)) &&
60 !isa<ConstantFP>(CV->getOperand(i)))
64 // Bitcast each element now.
65 std::vector<Constant*> Result;
66 Type *DstEltTy = DstTy->getElementType();
67 for (unsigned i = 0; i != NumElts; ++i)
68 Result.push_back(ConstantExpr::getBitCast(CV->getOperand(i),
70 return ConstantVector::get(Result);
73 /// This function determines which opcode to use to fold two constant cast
74 /// expressions together. It uses CastInst::isEliminableCastPair to determine
75 /// the opcode. Consequently its just a wrapper around that function.
76 /// @brief Determine if it is valid to fold a cast of a cast
79 unsigned opc, ///< opcode of the second cast constant expression
80 ConstantExpr *Op, ///< the first cast constant expression
81 Type *DstTy ///< desintation type of the first cast
83 assert(Op && Op->isCast() && "Can't fold cast of cast without a cast!");
84 assert(DstTy && DstTy->isFirstClassType() && "Invalid cast destination type");
85 assert(CastInst::isCast(opc) && "Invalid cast opcode");
87 // The the types and opcodes for the two Cast constant expressions
88 Type *SrcTy = Op->getOperand(0)->getType();
89 Type *MidTy = Op->getType();
90 Instruction::CastOps firstOp = Instruction::CastOps(Op->getOpcode());
91 Instruction::CastOps secondOp = Instruction::CastOps(opc);
93 // Let CastInst::isEliminableCastPair do the heavy lifting.
94 return CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy, DstTy,
95 Type::getInt64Ty(DstTy->getContext()));
98 static Constant *FoldBitCast(Constant *V, Type *DestTy) {
99 Type *SrcTy = V->getType();
101 return V; // no-op cast
103 // Check to see if we are casting a pointer to an aggregate to a pointer to
104 // the first element. If so, return the appropriate GEP instruction.
105 if (PointerType *PTy = dyn_cast<PointerType>(V->getType()))
106 if (PointerType *DPTy = dyn_cast<PointerType>(DestTy))
107 if (PTy->getAddressSpace() == DPTy->getAddressSpace()
108 && DPTy->getElementType()->isSized()) {
109 SmallVector<Value*, 8> IdxList;
111 Constant::getNullValue(Type::getInt32Ty(DPTy->getContext()));
112 IdxList.push_back(Zero);
113 Type *ElTy = PTy->getElementType();
114 while (ElTy != DPTy->getElementType()) {
115 if (StructType *STy = dyn_cast<StructType>(ElTy)) {
116 if (STy->getNumElements() == 0) break;
117 ElTy = STy->getElementType(0);
118 IdxList.push_back(Zero);
119 } else if (SequentialType *STy =
120 dyn_cast<SequentialType>(ElTy)) {
121 if (ElTy->isPointerTy()) break; // Can't index into pointers!
122 ElTy = STy->getElementType();
123 IdxList.push_back(Zero);
129 if (ElTy == DPTy->getElementType())
130 // This GEP is inbounds because all indices are zero.
131 return ConstantExpr::getInBoundsGetElementPtr(V, IdxList);
134 // Handle casts from one vector constant to another. We know that the src
135 // and dest type have the same size (otherwise its an illegal cast).
136 if (VectorType *DestPTy = dyn_cast<VectorType>(DestTy)) {
137 if (VectorType *SrcTy = dyn_cast<VectorType>(V->getType())) {
138 assert(DestPTy->getBitWidth() == SrcTy->getBitWidth() &&
139 "Not cast between same sized vectors!");
141 // First, check for null. Undef is already handled.
142 if (isa<ConstantAggregateZero>(V))
143 return Constant::getNullValue(DestTy);
145 if (ConstantVector *CV = dyn_cast<ConstantVector>(V))
146 return BitCastConstantVector(CV, DestPTy);
149 // Canonicalize scalar-to-vector bitcasts into vector-to-vector bitcasts
150 // This allows for other simplifications (although some of them
151 // can only be handled by Analysis/ConstantFolding.cpp).
152 if (isa<ConstantInt>(V) || isa<ConstantFP>(V))
153 return ConstantExpr::getBitCast(ConstantVector::get(V), DestPTy);
156 // Finally, implement bitcast folding now. The code below doesn't handle
158 if (isa<ConstantPointerNull>(V)) // ptr->ptr cast.
159 return ConstantPointerNull::get(cast<PointerType>(DestTy));
161 // Handle integral constant input.
162 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
163 if (DestTy->isIntegerTy())
164 // Integral -> Integral. This is a no-op because the bit widths must
165 // be the same. Consequently, we just fold to V.
168 if (DestTy->isFloatingPointTy())
169 return ConstantFP::get(DestTy->getContext(),
170 APFloat(CI->getValue(),
171 !DestTy->isPPC_FP128Ty()));
173 // Otherwise, can't fold this (vector?)
177 // Handle ConstantFP input: FP -> Integral.
178 if (ConstantFP *FP = dyn_cast<ConstantFP>(V))
179 return ConstantInt::get(FP->getContext(),
180 FP->getValueAPF().bitcastToAPInt());
186 /// ExtractConstantBytes - V is an integer constant which only has a subset of
187 /// its bytes used. The bytes used are indicated by ByteStart (which is the
188 /// first byte used, counting from the least significant byte) and ByteSize,
189 /// which is the number of bytes used.
191 /// This function analyzes the specified constant to see if the specified byte
192 /// range can be returned as a simplified constant. If so, the constant is
193 /// returned, otherwise null is returned.
195 static Constant *ExtractConstantBytes(Constant *C, unsigned ByteStart,
197 assert(C->getType()->isIntegerTy() &&
198 (cast<IntegerType>(C->getType())->getBitWidth() & 7) == 0 &&
199 "Non-byte sized integer input");
200 unsigned CSize = cast<IntegerType>(C->getType())->getBitWidth()/8;
201 assert(ByteSize && "Must be accessing some piece");
202 assert(ByteStart+ByteSize <= CSize && "Extracting invalid piece from input");
203 assert(ByteSize != CSize && "Should not extract everything");
205 // Constant Integers are simple.
206 if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
207 APInt V = CI->getValue();
209 V = V.lshr(ByteStart*8);
210 V = V.trunc(ByteSize*8);
211 return ConstantInt::get(CI->getContext(), V);
214 // In the input is a constant expr, we might be able to recursively simplify.
215 // If not, we definitely can't do anything.
216 ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
217 if (CE == 0) return 0;
219 switch (CE->getOpcode()) {
221 case Instruction::Or: {
222 Constant *RHS = ExtractConstantBytes(CE->getOperand(1), ByteStart,ByteSize);
227 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS))
228 if (RHSC->isAllOnesValue())
231 Constant *LHS = ExtractConstantBytes(CE->getOperand(0), ByteStart,ByteSize);
234 return ConstantExpr::getOr(LHS, RHS);
236 case Instruction::And: {
237 Constant *RHS = ExtractConstantBytes(CE->getOperand(1), ByteStart,ByteSize);
242 if (RHS->isNullValue())
245 Constant *LHS = ExtractConstantBytes(CE->getOperand(0), ByteStart,ByteSize);
248 return ConstantExpr::getAnd(LHS, RHS);
250 case Instruction::LShr: {
251 ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
254 unsigned ShAmt = Amt->getZExtValue();
255 // Cannot analyze non-byte shifts.
256 if ((ShAmt & 7) != 0)
260 // If the extract is known to be all zeros, return zero.
261 if (ByteStart >= CSize-ShAmt)
262 return Constant::getNullValue(IntegerType::get(CE->getContext(),
264 // If the extract is known to be fully in the input, extract it.
265 if (ByteStart+ByteSize+ShAmt <= CSize)
266 return ExtractConstantBytes(CE->getOperand(0), ByteStart+ShAmt, ByteSize);
268 // TODO: Handle the 'partially zero' case.
272 case Instruction::Shl: {
273 ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
276 unsigned ShAmt = Amt->getZExtValue();
277 // Cannot analyze non-byte shifts.
278 if ((ShAmt & 7) != 0)
282 // If the extract is known to be all zeros, return zero.
283 if (ByteStart+ByteSize <= ShAmt)
284 return Constant::getNullValue(IntegerType::get(CE->getContext(),
286 // If the extract is known to be fully in the input, extract it.
287 if (ByteStart >= ShAmt)
288 return ExtractConstantBytes(CE->getOperand(0), ByteStart-ShAmt, ByteSize);
290 // TODO: Handle the 'partially zero' case.
294 case Instruction::ZExt: {
295 unsigned SrcBitSize =
296 cast<IntegerType>(CE->getOperand(0)->getType())->getBitWidth();
298 // If extracting something that is completely zero, return 0.
299 if (ByteStart*8 >= SrcBitSize)
300 return Constant::getNullValue(IntegerType::get(CE->getContext(),
303 // If exactly extracting the input, return it.
304 if (ByteStart == 0 && ByteSize*8 == SrcBitSize)
305 return CE->getOperand(0);
307 // If extracting something completely in the input, if if the input is a
308 // multiple of 8 bits, recurse.
309 if ((SrcBitSize&7) == 0 && (ByteStart+ByteSize)*8 <= SrcBitSize)
310 return ExtractConstantBytes(CE->getOperand(0), ByteStart, ByteSize);
312 // Otherwise, if extracting a subset of the input, which is not multiple of
313 // 8 bits, do a shift and trunc to get the bits.
314 if ((ByteStart+ByteSize)*8 < SrcBitSize) {
315 assert((SrcBitSize&7) && "Shouldn't get byte sized case here");
316 Constant *Res = CE->getOperand(0);
318 Res = ConstantExpr::getLShr(Res,
319 ConstantInt::get(Res->getType(), ByteStart*8));
320 return ConstantExpr::getTrunc(Res, IntegerType::get(C->getContext(),
324 // TODO: Handle the 'partially zero' case.
330 /// getFoldedSizeOf - Return a ConstantExpr with type DestTy for sizeof
331 /// on Ty, with any known factors factored out. If Folded is false,
332 /// return null if no factoring was possible, to avoid endlessly
333 /// bouncing an unfoldable expression back into the top-level folder.
335 static Constant *getFoldedSizeOf(Type *Ty, Type *DestTy,
337 if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
338 Constant *N = ConstantInt::get(DestTy, ATy->getNumElements());
339 Constant *E = getFoldedSizeOf(ATy->getElementType(), DestTy, true);
340 return ConstantExpr::getNUWMul(E, N);
343 if (StructType *STy = dyn_cast<StructType>(Ty))
344 if (!STy->isPacked()) {
345 unsigned NumElems = STy->getNumElements();
346 // An empty struct has size zero.
348 return ConstantExpr::getNullValue(DestTy);
349 // Check for a struct with all members having the same size.
350 Constant *MemberSize =
351 getFoldedSizeOf(STy->getElementType(0), DestTy, true);
353 for (unsigned i = 1; i != NumElems; ++i)
355 getFoldedSizeOf(STy->getElementType(i), DestTy, true)) {
360 Constant *N = ConstantInt::get(DestTy, NumElems);
361 return ConstantExpr::getNUWMul(MemberSize, N);
365 // Pointer size doesn't depend on the pointee type, so canonicalize them
366 // to an arbitrary pointee.
367 if (PointerType *PTy = dyn_cast<PointerType>(Ty))
368 if (!PTy->getElementType()->isIntegerTy(1))
370 getFoldedSizeOf(PointerType::get(IntegerType::get(PTy->getContext(), 1),
371 PTy->getAddressSpace()),
374 // If there's no interesting folding happening, bail so that we don't create
375 // a constant that looks like it needs folding but really doesn't.
379 // Base case: Get a regular sizeof expression.
380 Constant *C = ConstantExpr::getSizeOf(Ty);
381 C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
387 /// getFoldedAlignOf - Return a ConstantExpr with type DestTy for alignof
388 /// on Ty, with any known factors factored out. If Folded is false,
389 /// return null if no factoring was possible, to avoid endlessly
390 /// bouncing an unfoldable expression back into the top-level folder.
392 static Constant *getFoldedAlignOf(Type *Ty, Type *DestTy,
394 // The alignment of an array is equal to the alignment of the
395 // array element. Note that this is not always true for vectors.
396 if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
397 Constant *C = ConstantExpr::getAlignOf(ATy->getElementType());
398 C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
405 if (StructType *STy = dyn_cast<StructType>(Ty)) {
406 // Packed structs always have an alignment of 1.
408 return ConstantInt::get(DestTy, 1);
410 // Otherwise, struct alignment is the maximum alignment of any member.
411 // Without target data, we can't compare much, but we can check to see
412 // if all the members have the same alignment.
413 unsigned NumElems = STy->getNumElements();
414 // An empty struct has minimal alignment.
416 return ConstantInt::get(DestTy, 1);
417 // Check for a struct with all members having the same alignment.
418 Constant *MemberAlign =
419 getFoldedAlignOf(STy->getElementType(0), DestTy, true);
421 for (unsigned i = 1; i != NumElems; ++i)
422 if (MemberAlign != getFoldedAlignOf(STy->getElementType(i), DestTy, true)) {
430 // Pointer alignment doesn't depend on the pointee type, so canonicalize them
431 // to an arbitrary pointee.
432 if (PointerType *PTy = dyn_cast<PointerType>(Ty))
433 if (!PTy->getElementType()->isIntegerTy(1))
435 getFoldedAlignOf(PointerType::get(IntegerType::get(PTy->getContext(),
437 PTy->getAddressSpace()),
440 // If there's no interesting folding happening, bail so that we don't create
441 // a constant that looks like it needs folding but really doesn't.
445 // Base case: Get a regular alignof expression.
446 Constant *C = ConstantExpr::getAlignOf(Ty);
447 C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
453 /// getFoldedOffsetOf - Return a ConstantExpr with type DestTy for offsetof
454 /// on Ty and FieldNo, with any known factors factored out. If Folded is false,
455 /// return null if no factoring was possible, to avoid endlessly
456 /// bouncing an unfoldable expression back into the top-level folder.
458 static Constant *getFoldedOffsetOf(Type *Ty, Constant *FieldNo,
461 if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
462 Constant *N = ConstantExpr::getCast(CastInst::getCastOpcode(FieldNo, false,
465 Constant *E = getFoldedSizeOf(ATy->getElementType(), DestTy, true);
466 return ConstantExpr::getNUWMul(E, N);
469 if (StructType *STy = dyn_cast<StructType>(Ty))
470 if (!STy->isPacked()) {
471 unsigned NumElems = STy->getNumElements();
472 // An empty struct has no members.
475 // Check for a struct with all members having the same size.
476 Constant *MemberSize =
477 getFoldedSizeOf(STy->getElementType(0), DestTy, true);
479 for (unsigned i = 1; i != NumElems; ++i)
481 getFoldedSizeOf(STy->getElementType(i), DestTy, true)) {
486 Constant *N = ConstantExpr::getCast(CastInst::getCastOpcode(FieldNo,
491 return ConstantExpr::getNUWMul(MemberSize, N);
495 // If there's no interesting folding happening, bail so that we don't create
496 // a constant that looks like it needs folding but really doesn't.
500 // Base case: Get a regular offsetof expression.
501 Constant *C = ConstantExpr::getOffsetOf(Ty, FieldNo);
502 C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
508 Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V,
510 if (isa<UndefValue>(V)) {
511 // zext(undef) = 0, because the top bits will be zero.
512 // sext(undef) = 0, because the top bits will all be the same.
513 // [us]itofp(undef) = 0, because the result value is bounded.
514 if (opc == Instruction::ZExt || opc == Instruction::SExt ||
515 opc == Instruction::UIToFP || opc == Instruction::SIToFP)
516 return Constant::getNullValue(DestTy);
517 return UndefValue::get(DestTy);
520 // No compile-time operations on this type yet.
521 if (V->getType()->isPPC_FP128Ty() || DestTy->isPPC_FP128Ty())
524 if (V->isNullValue() && !DestTy->isX86_MMXTy())
525 return Constant::getNullValue(DestTy);
527 // If the cast operand is a constant expression, there's a few things we can
528 // do to try to simplify it.
529 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
531 // Try hard to fold cast of cast because they are often eliminable.
532 if (unsigned newOpc = foldConstantCastPair(opc, CE, DestTy))
533 return ConstantExpr::getCast(newOpc, CE->getOperand(0), DestTy);
534 } else if (CE->getOpcode() == Instruction::GetElementPtr) {
535 // If all of the indexes in the GEP are null values, there is no pointer
536 // adjustment going on. We might as well cast the source pointer.
537 bool isAllNull = true;
538 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
539 if (!CE->getOperand(i)->isNullValue()) {
544 // This is casting one pointer type to another, always BitCast
545 return ConstantExpr::getPointerCast(CE->getOperand(0), DestTy);
549 // If the cast operand is a constant vector, perform the cast by
550 // operating on each element. In the cast of bitcasts, the element
551 // count may be mismatched; don't attempt to handle that here.
552 if (ConstantVector *CV = dyn_cast<ConstantVector>(V))
553 if (DestTy->isVectorTy() &&
554 cast<VectorType>(DestTy)->getNumElements() ==
555 CV->getType()->getNumElements()) {
556 std::vector<Constant*> res;
557 VectorType *DestVecTy = cast<VectorType>(DestTy);
558 Type *DstEltTy = DestVecTy->getElementType();
559 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
560 res.push_back(ConstantExpr::getCast(opc,
561 CV->getOperand(i), DstEltTy));
562 return ConstantVector::get(res);
565 // We actually have to do a cast now. Perform the cast according to the
569 llvm_unreachable("Failed to cast constant expression");
570 case Instruction::FPTrunc:
571 case Instruction::FPExt:
572 if (ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
574 APFloat Val = FPC->getValueAPF();
575 Val.convert(DestTy->isHalfTy() ? APFloat::IEEEhalf :
576 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, 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 (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 (Ty->isStructTy() || Ty->isArrayTy()) {
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 APFloat apf(APInt::getNullValue(DestTy->getPrimitiveSizeInBits()), true);
651 (void)apf.convertFromAPInt(api,
652 opc==Instruction::SIToFP,
653 APFloat::rmNearestTiesToEven);
654 return ConstantFP::get(V->getContext(), apf);
657 case Instruction::ZExt:
658 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
659 uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
660 return ConstantInt::get(V->getContext(),
661 CI->getValue().zext(BitWidth));
664 case Instruction::SExt:
665 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
666 uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
667 return ConstantInt::get(V->getContext(),
668 CI->getValue().sext(BitWidth));
671 case Instruction::Trunc: {
672 uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
673 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
674 return ConstantInt::get(V->getContext(),
675 CI->getValue().trunc(DestBitWidth));
678 // The input must be a constantexpr. See if we can simplify this based on
679 // the bytes we are demanding. Only do this if the source and dest are an
680 // even multiple of a byte.
681 if ((DestBitWidth & 7) == 0 &&
682 (cast<IntegerType>(V->getType())->getBitWidth() & 7) == 0)
683 if (Constant *Res = ExtractConstantBytes(V, 0, DestBitWidth / 8))
688 case Instruction::BitCast:
689 return FoldBitCast(V, DestTy);
693 Constant *llvm::ConstantFoldSelectInstruction(Constant *Cond,
694 Constant *V1, Constant *V2) {
695 if (ConstantInt *CB = dyn_cast<ConstantInt>(Cond))
696 return CB->getZExtValue() ? V1 : V2;
698 // Check for zero aggregate and ConstantVector of zeros
699 if (Cond->isNullValue()) return V2;
701 if (ConstantVector* CondV = dyn_cast<ConstantVector>(Cond)) {
703 if (CondV->isAllOnesValue()) return V1;
705 VectorType *VTy = cast<VectorType>(V1->getType());
706 ConstantVector *CP1 = dyn_cast<ConstantVector>(V1);
707 ConstantVector *CP2 = dyn_cast<ConstantVector>(V2);
709 if ((CP1 || isa<ConstantAggregateZero>(V1)) &&
710 (CP2 || isa<ConstantAggregateZero>(V2))) {
712 // Find the element type of the returned vector
713 Type *EltTy = VTy->getElementType();
714 unsigned NumElem = VTy->getNumElements();
715 std::vector<Constant*> Res(NumElem);
718 for (unsigned i = 0; i < NumElem; ++i) {
719 ConstantInt* c = dyn_cast<ConstantInt>(CondV->getOperand(i));
724 Constant *C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
725 Constant *C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
726 Res[i] = c->getZExtValue() ? C1 : C2;
728 // If we were able to build the vector, return it
729 if (Valid) return ConstantVector::get(Res);
734 if (isa<UndefValue>(Cond)) {
735 if (isa<UndefValue>(V1)) return V1;
738 if (isa<UndefValue>(V1)) return V2;
739 if (isa<UndefValue>(V2)) return V1;
740 if (V1 == V2) return V1;
742 if (ConstantExpr *TrueVal = dyn_cast<ConstantExpr>(V1)) {
743 if (TrueVal->getOpcode() == Instruction::Select)
744 if (TrueVal->getOperand(0) == Cond)
745 return ConstantExpr::getSelect(Cond, TrueVal->getOperand(1), V2);
747 if (ConstantExpr *FalseVal = dyn_cast<ConstantExpr>(V2)) {
748 if (FalseVal->getOpcode() == Instruction::Select)
749 if (FalseVal->getOperand(0) == Cond)
750 return ConstantExpr::getSelect(Cond, V1, FalseVal->getOperand(2));
756 Constant *llvm::ConstantFoldExtractElementInstruction(Constant *Val,
758 if (isa<UndefValue>(Val)) // ee(undef, x) -> undef
759 return UndefValue::get(cast<VectorType>(Val->getType())->getElementType());
760 if (Val->isNullValue()) // ee(zero, x) -> zero
761 return Constant::getNullValue(
762 cast<VectorType>(Val->getType())->getElementType());
764 if (ConstantVector *CVal = dyn_cast<ConstantVector>(Val)) {
765 if (ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx)) {
766 uint64_t Index = CIdx->getZExtValue();
767 if (Index >= CVal->getNumOperands())
768 // ee({w,x,y,z}, wrong_value) -> undef
769 return UndefValue::get(cast<VectorType>(Val->getType())->getElementType());
770 return CVal->getOperand(CIdx->getZExtValue());
771 } else if (isa<UndefValue>(Idx)) {
772 // ee({w,x,y,z}, undef) -> undef
773 return UndefValue::get(cast<VectorType>(Val->getType())->getElementType());
779 Constant *llvm::ConstantFoldInsertElementInstruction(Constant *Val,
782 ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx);
784 APInt idxVal = CIdx->getValue();
785 if (isa<UndefValue>(Val)) {
786 // Insertion of scalar constant into vector undef
787 // Optimize away insertion of undef
788 if (isa<UndefValue>(Elt))
790 // Otherwise break the aggregate undef into multiple undefs and do
793 cast<VectorType>(Val->getType())->getNumElements();
794 std::vector<Constant*> Ops;
796 for (unsigned i = 0; i < numOps; ++i) {
798 (idxVal == i) ? Elt : UndefValue::get(Elt->getType());
801 return ConstantVector::get(Ops);
803 if (isa<ConstantAggregateZero>(Val)) {
804 // Insertion of scalar constant into vector aggregate zero
805 // Optimize away insertion of zero
806 if (Elt->isNullValue())
808 // Otherwise break the aggregate zero into multiple zeros and do
811 cast<VectorType>(Val->getType())->getNumElements();
812 std::vector<Constant*> Ops;
814 for (unsigned i = 0; i < numOps; ++i) {
816 (idxVal == i) ? Elt : Constant::getNullValue(Elt->getType());
819 return ConstantVector::get(Ops);
821 if (ConstantVector *CVal = dyn_cast<ConstantVector>(Val)) {
822 // Insertion of scalar constant into vector constant
823 std::vector<Constant*> Ops;
824 Ops.reserve(CVal->getNumOperands());
825 for (unsigned i = 0; i < CVal->getNumOperands(); ++i) {
827 (idxVal == i) ? Elt : cast<Constant>(CVal->getOperand(i));
830 return ConstantVector::get(Ops);
836 /// GetVectorElement - If C is a ConstantVector, ConstantAggregateZero or Undef
837 /// return the specified element value. Otherwise return null.
838 static Constant *GetVectorElement(Constant *C, unsigned EltNo) {
839 if (ConstantVector *CV = dyn_cast<ConstantVector>(C))
840 return CV->getOperand(EltNo);
842 Type *EltTy = cast<VectorType>(C->getType())->getElementType();
843 if (isa<ConstantAggregateZero>(C))
844 return Constant::getNullValue(EltTy);
845 if (isa<UndefValue>(C))
846 return UndefValue::get(EltTy);
850 Constant *llvm::ConstantFoldShuffleVectorInstruction(Constant *V1,
853 // Undefined shuffle mask -> undefined value.
854 if (isa<UndefValue>(Mask)) return UndefValue::get(V1->getType());
856 unsigned MaskNumElts = cast<VectorType>(Mask->getType())->getNumElements();
857 unsigned SrcNumElts = cast<VectorType>(V1->getType())->getNumElements();
858 Type *EltTy = cast<VectorType>(V1->getType())->getElementType();
860 // Loop over the shuffle mask, evaluating each element.
861 SmallVector<Constant*, 32> Result;
862 for (unsigned i = 0; i != MaskNumElts; ++i) {
863 Constant *InElt = GetVectorElement(Mask, i);
864 if (InElt == 0) return 0;
866 if (isa<UndefValue>(InElt))
867 InElt = UndefValue::get(EltTy);
868 else if (ConstantInt *CI = dyn_cast<ConstantInt>(InElt)) {
869 unsigned Elt = CI->getZExtValue();
870 if (Elt >= SrcNumElts*2)
871 InElt = UndefValue::get(EltTy);
872 else if (Elt >= SrcNumElts)
873 InElt = GetVectorElement(V2, Elt - SrcNumElts);
875 InElt = GetVectorElement(V1, Elt);
876 if (InElt == 0) return 0;
881 Result.push_back(InElt);
884 return ConstantVector::get(Result);
887 Constant *llvm::ConstantFoldExtractValueInstruction(Constant *Agg,
888 ArrayRef<unsigned> Idxs) {
889 // Base case: no indices, so return the entire value.
893 if (isa<UndefValue>(Agg)) // ev(undef, x) -> undef
894 return UndefValue::get(ExtractValueInst::getIndexedType(Agg->getType(),
897 if (isa<ConstantAggregateZero>(Agg)) // ev(0, x) -> 0
899 Constant::getNullValue(ExtractValueInst::getIndexedType(Agg->getType(),
902 // Otherwise recurse.
903 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(Agg))
904 return ConstantFoldExtractValueInstruction(CS->getOperand(Idxs[0]),
907 if (ConstantArray *CA = dyn_cast<ConstantArray>(Agg))
908 return ConstantFoldExtractValueInstruction(CA->getOperand(Idxs[0]),
910 ConstantVector *CV = cast<ConstantVector>(Agg);
911 return ConstantFoldExtractValueInstruction(CV->getOperand(Idxs[0]),
915 Constant *llvm::ConstantFoldInsertValueInstruction(Constant *Agg,
917 ArrayRef<unsigned> Idxs) {
918 // Base case: no indices, so replace the entire value.
922 if (isa<UndefValue>(Agg)) {
923 // Insertion of constant into aggregate undef
924 // Optimize away insertion of undef.
925 if (isa<UndefValue>(Val))
928 // Otherwise break the aggregate undef into multiple undefs and do
930 CompositeType *AggTy = cast<CompositeType>(Agg->getType());
932 if (ArrayType *AR = dyn_cast<ArrayType>(AggTy))
933 numOps = AR->getNumElements();
935 numOps = cast<StructType>(AggTy)->getNumElements();
937 std::vector<Constant*> Ops(numOps);
938 for (unsigned i = 0; i < numOps; ++i) {
939 Type *MemberTy = AggTy->getTypeAtIndex(i);
942 ConstantFoldInsertValueInstruction(UndefValue::get(MemberTy),
943 Val, Idxs.slice(1)) :
944 UndefValue::get(MemberTy);
948 if (StructType* ST = dyn_cast<StructType>(AggTy))
949 return ConstantStruct::get(ST, Ops);
950 return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
953 if (isa<ConstantAggregateZero>(Agg)) {
954 // Insertion of constant into aggregate zero
955 // Optimize away insertion of zero.
956 if (Val->isNullValue())
959 // Otherwise break the aggregate zero into multiple zeros and do
961 CompositeType *AggTy = cast<CompositeType>(Agg->getType());
963 if (ArrayType *AR = dyn_cast<ArrayType>(AggTy))
964 numOps = AR->getNumElements();
966 numOps = cast<StructType>(AggTy)->getNumElements();
968 std::vector<Constant*> Ops(numOps);
969 for (unsigned i = 0; i < numOps; ++i) {
970 Type *MemberTy = AggTy->getTypeAtIndex(i);
973 ConstantFoldInsertValueInstruction(Constant::getNullValue(MemberTy),
974 Val, Idxs.slice(1)) :
975 Constant::getNullValue(MemberTy);
979 if (StructType *ST = dyn_cast<StructType>(AggTy))
980 return ConstantStruct::get(ST, Ops);
981 return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
984 if (isa<ConstantStruct>(Agg) || isa<ConstantArray>(Agg)) {
985 // Insertion of constant into aggregate constant.
986 std::vector<Constant*> Ops(Agg->getNumOperands());
987 for (unsigned i = 0; i < Agg->getNumOperands(); ++i) {
988 Constant *Op = cast<Constant>(Agg->getOperand(i));
990 Op = ConstantFoldInsertValueInstruction(Op, Val, Idxs.slice(1));
994 if (StructType* ST = dyn_cast<StructType>(Agg->getType()))
995 return ConstantStruct::get(ST, Ops);
996 return ConstantArray::get(cast<ArrayType>(Agg->getType()), Ops);
1003 Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
1004 Constant *C1, Constant *C2) {
1005 // No compile-time operations on this type yet.
1006 if (C1->getType()->isPPC_FP128Ty())
1009 // Handle UndefValue up front.
1010 if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
1012 case Instruction::Xor:
1013 if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
1014 // Handle undef ^ undef -> 0 special case. This is a common
1016 return Constant::getNullValue(C1->getType());
1018 case Instruction::Add:
1019 case Instruction::Sub:
1020 return UndefValue::get(C1->getType());
1021 case Instruction::And:
1022 if (isa<UndefValue>(C1) && isa<UndefValue>(C2)) // undef & undef -> undef
1024 return Constant::getNullValue(C1->getType()); // undef & X -> 0
1025 case Instruction::Mul: {
1027 // X * undef -> undef if X is odd or undef
1028 if (((CI = dyn_cast<ConstantInt>(C1)) && CI->getValue()[0]) ||
1029 ((CI = dyn_cast<ConstantInt>(C2)) && CI->getValue()[0]) ||
1030 (isa<UndefValue>(C1) && isa<UndefValue>(C2)))
1031 return UndefValue::get(C1->getType());
1033 // X * undef -> 0 otherwise
1034 return Constant::getNullValue(C1->getType());
1036 case Instruction::UDiv:
1037 case Instruction::SDiv:
1038 // undef / 1 -> undef
1039 if (Opcode == Instruction::UDiv || Opcode == Instruction::SDiv)
1040 if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2))
1044 case Instruction::URem:
1045 case Instruction::SRem:
1046 if (!isa<UndefValue>(C2)) // undef / X -> 0
1047 return Constant::getNullValue(C1->getType());
1048 return C2; // X / undef -> undef
1049 case Instruction::Or: // X | undef -> -1
1050 if (isa<UndefValue>(C1) && isa<UndefValue>(C2)) // undef | undef -> undef
1052 return Constant::getAllOnesValue(C1->getType()); // undef | X -> ~0
1053 case Instruction::LShr:
1054 if (isa<UndefValue>(C2) && isa<UndefValue>(C1))
1055 return C1; // undef lshr undef -> undef
1056 return Constant::getNullValue(C1->getType()); // X lshr undef -> 0
1057 // undef lshr X -> 0
1058 case Instruction::AShr:
1059 if (!isa<UndefValue>(C2)) // undef ashr X --> all ones
1060 return Constant::getAllOnesValue(C1->getType());
1061 else if (isa<UndefValue>(C1))
1062 return C1; // undef ashr undef -> undef
1064 return C1; // X ashr undef --> X
1065 case Instruction::Shl:
1066 if (isa<UndefValue>(C2) && isa<UndefValue>(C1))
1067 return C1; // undef shl undef -> undef
1068 // undef << X -> 0 or X << undef -> 0
1069 return Constant::getNullValue(C1->getType());
1073 // Handle simplifications when the RHS is a constant int.
1074 if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
1076 case Instruction::Add:
1077 if (CI2->equalsInt(0)) return C1; // X + 0 == X
1079 case Instruction::Sub:
1080 if (CI2->equalsInt(0)) return C1; // X - 0 == X
1082 case Instruction::Mul:
1083 if (CI2->equalsInt(0)) return C2; // X * 0 == 0
1084 if (CI2->equalsInt(1))
1085 return C1; // X * 1 == X
1087 case Instruction::UDiv:
1088 case Instruction::SDiv:
1089 if (CI2->equalsInt(1))
1090 return C1; // X / 1 == X
1091 if (CI2->equalsInt(0))
1092 return UndefValue::get(CI2->getType()); // X / 0 == undef
1094 case Instruction::URem:
1095 case Instruction::SRem:
1096 if (CI2->equalsInt(1))
1097 return Constant::getNullValue(CI2->getType()); // X % 1 == 0
1098 if (CI2->equalsInt(0))
1099 return UndefValue::get(CI2->getType()); // X % 0 == undef
1101 case Instruction::And:
1102 if (CI2->isZero()) return C2; // X & 0 == 0
1103 if (CI2->isAllOnesValue())
1104 return C1; // X & -1 == X
1106 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1107 // (zext i32 to i64) & 4294967295 -> (zext i32 to i64)
1108 if (CE1->getOpcode() == Instruction::ZExt) {
1109 unsigned DstWidth = CI2->getType()->getBitWidth();
1111 CE1->getOperand(0)->getType()->getPrimitiveSizeInBits();
1112 APInt PossiblySetBits(APInt::getLowBitsSet(DstWidth, SrcWidth));
1113 if ((PossiblySetBits & CI2->getValue()) == PossiblySetBits)
1117 // If and'ing the address of a global with a constant, fold it.
1118 if (CE1->getOpcode() == Instruction::PtrToInt &&
1119 isa<GlobalValue>(CE1->getOperand(0))) {
1120 GlobalValue *GV = cast<GlobalValue>(CE1->getOperand(0));
1122 // Functions are at least 4-byte aligned.
1123 unsigned GVAlign = GV->getAlignment();
1124 if (isa<Function>(GV))
1125 GVAlign = std::max(GVAlign, 4U);
1128 unsigned DstWidth = CI2->getType()->getBitWidth();
1129 unsigned SrcWidth = std::min(DstWidth, Log2_32(GVAlign));
1130 APInt BitsNotSet(APInt::getLowBitsSet(DstWidth, SrcWidth));
1132 // If checking bits we know are clear, return zero.
1133 if ((CI2->getValue() & BitsNotSet) == CI2->getValue())
1134 return Constant::getNullValue(CI2->getType());
1139 case Instruction::Or:
1140 if (CI2->equalsInt(0)) return C1; // X | 0 == X
1141 if (CI2->isAllOnesValue())
1142 return C2; // X | -1 == -1
1144 case Instruction::Xor:
1145 if (CI2->equalsInt(0)) return C1; // X ^ 0 == X
1147 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1148 switch (CE1->getOpcode()) {
1150 case Instruction::ICmp:
1151 case Instruction::FCmp:
1152 // cmp pred ^ true -> cmp !pred
1153 assert(CI2->equalsInt(1));
1154 CmpInst::Predicate pred = (CmpInst::Predicate)CE1->getPredicate();
1155 pred = CmpInst::getInversePredicate(pred);
1156 return ConstantExpr::getCompare(pred, CE1->getOperand(0),
1157 CE1->getOperand(1));
1161 case Instruction::AShr:
1162 // ashr (zext C to Ty), C2 -> lshr (zext C, CSA), C2
1163 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1))
1164 if (CE1->getOpcode() == Instruction::ZExt) // Top bits known zero.
1165 return ConstantExpr::getLShr(C1, C2);
1168 } else if (isa<ConstantInt>(C1)) {
1169 // If C1 is a ConstantInt and C2 is not, swap the operands.
1170 if (Instruction::isCommutative(Opcode))
1171 return ConstantExpr::get(Opcode, C2, C1);
1174 // At this point we know neither constant is an UndefValue.
1175 if (ConstantInt *CI1 = dyn_cast<ConstantInt>(C1)) {
1176 if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
1177 using namespace APIntOps;
1178 const APInt &C1V = CI1->getValue();
1179 const APInt &C2V = CI2->getValue();
1183 case Instruction::Add:
1184 return ConstantInt::get(CI1->getContext(), C1V + C2V);
1185 case Instruction::Sub:
1186 return ConstantInt::get(CI1->getContext(), C1V - C2V);
1187 case Instruction::Mul:
1188 return ConstantInt::get(CI1->getContext(), C1V * C2V);
1189 case Instruction::UDiv:
1190 assert(!CI2->isNullValue() && "Div by zero handled above");
1191 return ConstantInt::get(CI1->getContext(), C1V.udiv(C2V));
1192 case Instruction::SDiv:
1193 assert(!CI2->isNullValue() && "Div by zero handled above");
1194 if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
1195 return UndefValue::get(CI1->getType()); // MIN_INT / -1 -> undef
1196 return ConstantInt::get(CI1->getContext(), C1V.sdiv(C2V));
1197 case Instruction::URem:
1198 assert(!CI2->isNullValue() && "Div by zero handled above");
1199 return ConstantInt::get(CI1->getContext(), C1V.urem(C2V));
1200 case Instruction::SRem:
1201 assert(!CI2->isNullValue() && "Div by zero handled above");
1202 if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
1203 return UndefValue::get(CI1->getType()); // MIN_INT % -1 -> undef
1204 return ConstantInt::get(CI1->getContext(), C1V.srem(C2V));
1205 case Instruction::And:
1206 return ConstantInt::get(CI1->getContext(), C1V & C2V);
1207 case Instruction::Or:
1208 return ConstantInt::get(CI1->getContext(), C1V | C2V);
1209 case Instruction::Xor:
1210 return ConstantInt::get(CI1->getContext(), C1V ^ C2V);
1211 case Instruction::Shl: {
1212 uint32_t shiftAmt = C2V.getZExtValue();
1213 if (shiftAmt < C1V.getBitWidth())
1214 return ConstantInt::get(CI1->getContext(), C1V.shl(shiftAmt));
1216 return UndefValue::get(C1->getType()); // too big shift is undef
1218 case Instruction::LShr: {
1219 uint32_t shiftAmt = C2V.getZExtValue();
1220 if (shiftAmt < C1V.getBitWidth())
1221 return ConstantInt::get(CI1->getContext(), C1V.lshr(shiftAmt));
1223 return UndefValue::get(C1->getType()); // too big shift is undef
1225 case Instruction::AShr: {
1226 uint32_t shiftAmt = C2V.getZExtValue();
1227 if (shiftAmt < C1V.getBitWidth())
1228 return ConstantInt::get(CI1->getContext(), C1V.ashr(shiftAmt));
1230 return UndefValue::get(C1->getType()); // too big shift is undef
1236 case Instruction::SDiv:
1237 case Instruction::UDiv:
1238 case Instruction::URem:
1239 case Instruction::SRem:
1240 case Instruction::LShr:
1241 case Instruction::AShr:
1242 case Instruction::Shl:
1243 if (CI1->equalsInt(0)) return C1;
1248 } else if (ConstantFP *CFP1 = dyn_cast<ConstantFP>(C1)) {
1249 if (ConstantFP *CFP2 = dyn_cast<ConstantFP>(C2)) {
1250 APFloat C1V = CFP1->getValueAPF();
1251 APFloat C2V = CFP2->getValueAPF();
1252 APFloat C3V = C1V; // copy for modification
1256 case Instruction::FAdd:
1257 (void)C3V.add(C2V, APFloat::rmNearestTiesToEven);
1258 return ConstantFP::get(C1->getContext(), C3V);
1259 case Instruction::FSub:
1260 (void)C3V.subtract(C2V, APFloat::rmNearestTiesToEven);
1261 return ConstantFP::get(C1->getContext(), C3V);
1262 case Instruction::FMul:
1263 (void)C3V.multiply(C2V, APFloat::rmNearestTiesToEven);
1264 return ConstantFP::get(C1->getContext(), C3V);
1265 case Instruction::FDiv:
1266 (void)C3V.divide(C2V, APFloat::rmNearestTiesToEven);
1267 return ConstantFP::get(C1->getContext(), C3V);
1268 case Instruction::FRem:
1269 (void)C3V.mod(C2V, APFloat::rmNearestTiesToEven);
1270 return ConstantFP::get(C1->getContext(), C3V);
1273 } else if (VectorType *VTy = dyn_cast<VectorType>(C1->getType())) {
1274 ConstantVector *CP1 = dyn_cast<ConstantVector>(C1);
1275 ConstantVector *CP2 = dyn_cast<ConstantVector>(C2);
1276 if ((CP1 != NULL || isa<ConstantAggregateZero>(C1)) &&
1277 (CP2 != NULL || isa<ConstantAggregateZero>(C2))) {
1278 std::vector<Constant*> Res;
1279 Type* EltTy = VTy->getElementType();
1285 case Instruction::Add:
1286 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1287 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1288 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1289 Res.push_back(ConstantExpr::getAdd(C1, C2));
1291 return ConstantVector::get(Res);
1292 case Instruction::FAdd:
1293 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1294 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1295 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1296 Res.push_back(ConstantExpr::getFAdd(C1, C2));
1298 return ConstantVector::get(Res);
1299 case Instruction::Sub:
1300 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1301 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1302 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1303 Res.push_back(ConstantExpr::getSub(C1, C2));
1305 return ConstantVector::get(Res);
1306 case Instruction::FSub:
1307 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1308 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1309 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1310 Res.push_back(ConstantExpr::getFSub(C1, C2));
1312 return ConstantVector::get(Res);
1313 case Instruction::Mul:
1314 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1315 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1316 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1317 Res.push_back(ConstantExpr::getMul(C1, C2));
1319 return ConstantVector::get(Res);
1320 case Instruction::FMul:
1321 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1322 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1323 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1324 Res.push_back(ConstantExpr::getFMul(C1, C2));
1326 return ConstantVector::get(Res);
1327 case Instruction::UDiv:
1328 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1329 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1330 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1331 Res.push_back(ConstantExpr::getUDiv(C1, C2));
1333 return ConstantVector::get(Res);
1334 case Instruction::SDiv:
1335 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1336 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1337 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1338 Res.push_back(ConstantExpr::getSDiv(C1, C2));
1340 return ConstantVector::get(Res);
1341 case Instruction::FDiv:
1342 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1343 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1344 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1345 Res.push_back(ConstantExpr::getFDiv(C1, C2));
1347 return ConstantVector::get(Res);
1348 case Instruction::URem:
1349 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1350 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1351 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1352 Res.push_back(ConstantExpr::getURem(C1, C2));
1354 return ConstantVector::get(Res);
1355 case Instruction::SRem:
1356 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1357 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1358 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1359 Res.push_back(ConstantExpr::getSRem(C1, C2));
1361 return ConstantVector::get(Res);
1362 case Instruction::FRem:
1363 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1364 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1365 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1366 Res.push_back(ConstantExpr::getFRem(C1, C2));
1368 return ConstantVector::get(Res);
1369 case Instruction::And:
1370 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1371 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1372 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1373 Res.push_back(ConstantExpr::getAnd(C1, C2));
1375 return ConstantVector::get(Res);
1376 case Instruction::Or:
1377 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1378 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1379 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1380 Res.push_back(ConstantExpr::getOr(C1, C2));
1382 return ConstantVector::get(Res);
1383 case Instruction::Xor:
1384 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1385 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1386 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1387 Res.push_back(ConstantExpr::getXor(C1, C2));
1389 return ConstantVector::get(Res);
1390 case Instruction::LShr:
1391 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1392 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1393 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1394 Res.push_back(ConstantExpr::getLShr(C1, C2));
1396 return ConstantVector::get(Res);
1397 case Instruction::AShr:
1398 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1399 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1400 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1401 Res.push_back(ConstantExpr::getAShr(C1, C2));
1403 return ConstantVector::get(Res);
1404 case Instruction::Shl:
1405 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1406 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1407 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1408 Res.push_back(ConstantExpr::getShl(C1, C2));
1410 return ConstantVector::get(Res);
1415 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1416 // There are many possible foldings we could do here. We should probably
1417 // at least fold add of a pointer with an integer into the appropriate
1418 // getelementptr. This will improve alias analysis a bit.
1420 // Given ((a + b) + c), if (b + c) folds to something interesting, return
1422 if (Instruction::isAssociative(Opcode) && CE1->getOpcode() == Opcode) {
1423 Constant *T = ConstantExpr::get(Opcode, CE1->getOperand(1), C2);
1424 if (!isa<ConstantExpr>(T) || cast<ConstantExpr>(T)->getOpcode() != Opcode)
1425 return ConstantExpr::get(Opcode, CE1->getOperand(0), T);
1427 } else if (isa<ConstantExpr>(C2)) {
1428 // If C2 is a constant expr and C1 isn't, flop them around and fold the
1429 // other way if possible.
1430 if (Instruction::isCommutative(Opcode))
1431 return ConstantFoldBinaryInstruction(Opcode, C2, C1);
1434 // i1 can be simplified in many cases.
1435 if (C1->getType()->isIntegerTy(1)) {
1437 case Instruction::Add:
1438 case Instruction::Sub:
1439 return ConstantExpr::getXor(C1, C2);
1440 case Instruction::Mul:
1441 return ConstantExpr::getAnd(C1, C2);
1442 case Instruction::Shl:
1443 case Instruction::LShr:
1444 case Instruction::AShr:
1445 // We can assume that C2 == 0. If it were one the result would be
1446 // undefined because the shift value is as large as the bitwidth.
1448 case Instruction::SDiv:
1449 case Instruction::UDiv:
1450 // We can assume that C2 == 1. If it were zero the result would be
1451 // undefined through division by zero.
1453 case Instruction::URem:
1454 case Instruction::SRem:
1455 // We can assume that C2 == 1. If it were zero the result would be
1456 // undefined through division by zero.
1457 return ConstantInt::getFalse(C1->getContext());
1463 // We don't know how to fold this.
1467 /// isZeroSizedType - This type is zero sized if its an array or structure of
1468 /// zero sized types. The only leaf zero sized type is an empty structure.
1469 static bool isMaybeZeroSizedType(Type *Ty) {
1470 if (StructType *STy = dyn_cast<StructType>(Ty)) {
1471 if (STy->isOpaque()) return true; // Can't say.
1473 // If all of elements have zero size, this does too.
1474 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
1475 if (!isMaybeZeroSizedType(STy->getElementType(i))) return false;
1478 } else if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
1479 return isMaybeZeroSizedType(ATy->getElementType());
1484 /// IdxCompare - Compare the two constants as though they were getelementptr
1485 /// indices. This allows coersion of the types to be the same thing.
1487 /// If the two constants are the "same" (after coersion), return 0. If the
1488 /// first is less than the second, return -1, if the second is less than the
1489 /// first, return 1. If the constants are not integral, return -2.
1491 static int IdxCompare(Constant *C1, Constant *C2, Type *ElTy) {
1492 if (C1 == C2) return 0;
1494 // Ok, we found a different index. If they are not ConstantInt, we can't do
1495 // anything with them.
1496 if (!isa<ConstantInt>(C1) || !isa<ConstantInt>(C2))
1497 return -2; // don't know!
1499 // Ok, we have two differing integer indices. Sign extend them to be the same
1500 // type. Long is always big enough, so we use it.
1501 if (!C1->getType()->isIntegerTy(64))
1502 C1 = ConstantExpr::getSExt(C1, Type::getInt64Ty(C1->getContext()));
1504 if (!C2->getType()->isIntegerTy(64))
1505 C2 = ConstantExpr::getSExt(C2, Type::getInt64Ty(C1->getContext()));
1507 if (C1 == C2) return 0; // They are equal
1509 // If the type being indexed over is really just a zero sized type, there is
1510 // no pointer difference being made here.
1511 if (isMaybeZeroSizedType(ElTy))
1512 return -2; // dunno.
1514 // If they are really different, now that they are the same type, then we
1515 // found a difference!
1516 if (cast<ConstantInt>(C1)->getSExtValue() <
1517 cast<ConstantInt>(C2)->getSExtValue())
1523 /// evaluateFCmpRelation - This function determines if there is anything we can
1524 /// decide about the two constants provided. This doesn't need to handle simple
1525 /// things like ConstantFP comparisons, but should instead handle ConstantExprs.
1526 /// If we can determine that the two constants have a particular relation to
1527 /// each other, we should return the corresponding FCmpInst predicate,
1528 /// otherwise return FCmpInst::BAD_FCMP_PREDICATE. This is used below in
1529 /// ConstantFoldCompareInstruction.
1531 /// To simplify this code we canonicalize the relation so that the first
1532 /// operand is always the most "complex" of the two. We consider ConstantFP
1533 /// to be the simplest, and ConstantExprs to be the most complex.
1534 static FCmpInst::Predicate evaluateFCmpRelation(Constant *V1, Constant *V2) {
1535 assert(V1->getType() == V2->getType() &&
1536 "Cannot compare values of different types!");
1538 // No compile-time operations on this type yet.
1539 if (V1->getType()->isPPC_FP128Ty())
1540 return FCmpInst::BAD_FCMP_PREDICATE;
1542 // Handle degenerate case quickly
1543 if (V1 == V2) return FCmpInst::FCMP_OEQ;
1545 if (!isa<ConstantExpr>(V1)) {
1546 if (!isa<ConstantExpr>(V2)) {
1547 // We distilled thisUse the standard constant folder for a few cases
1549 R = dyn_cast<ConstantInt>(
1550 ConstantExpr::getFCmp(FCmpInst::FCMP_OEQ, V1, V2));
1551 if (R && !R->isZero())
1552 return FCmpInst::FCMP_OEQ;
1553 R = dyn_cast<ConstantInt>(
1554 ConstantExpr::getFCmp(FCmpInst::FCMP_OLT, V1, V2));
1555 if (R && !R->isZero())
1556 return FCmpInst::FCMP_OLT;
1557 R = dyn_cast<ConstantInt>(
1558 ConstantExpr::getFCmp(FCmpInst::FCMP_OGT, V1, V2));
1559 if (R && !R->isZero())
1560 return FCmpInst::FCMP_OGT;
1562 // Nothing more we can do
1563 return FCmpInst::BAD_FCMP_PREDICATE;
1566 // If the first operand is simple and second is ConstantExpr, swap operands.
1567 FCmpInst::Predicate SwappedRelation = evaluateFCmpRelation(V2, V1);
1568 if (SwappedRelation != FCmpInst::BAD_FCMP_PREDICATE)
1569 return FCmpInst::getSwappedPredicate(SwappedRelation);
1571 // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1572 // constantexpr or a simple constant.
1573 ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1574 switch (CE1->getOpcode()) {
1575 case Instruction::FPTrunc:
1576 case Instruction::FPExt:
1577 case Instruction::UIToFP:
1578 case Instruction::SIToFP:
1579 // We might be able to do something with these but we don't right now.
1585 // There are MANY other foldings that we could perform here. They will
1586 // probably be added on demand, as they seem needed.
1587 return FCmpInst::BAD_FCMP_PREDICATE;
1590 /// evaluateICmpRelation - This function determines if there is anything we can
1591 /// decide about the two constants provided. This doesn't need to handle simple
1592 /// things like integer comparisons, but should instead handle ConstantExprs
1593 /// and GlobalValues. If we can determine that the two constants have a
1594 /// particular relation to each other, we should return the corresponding ICmp
1595 /// predicate, otherwise return ICmpInst::BAD_ICMP_PREDICATE.
1597 /// To simplify this code we canonicalize the relation so that the first
1598 /// operand is always the most "complex" of the two. We consider simple
1599 /// constants (like ConstantInt) to be the simplest, followed by
1600 /// GlobalValues, followed by ConstantExpr's (the most complex).
1602 static ICmpInst::Predicate evaluateICmpRelation(Constant *V1, Constant *V2,
1604 assert(V1->getType() == V2->getType() &&
1605 "Cannot compare different types of values!");
1606 if (V1 == V2) return ICmpInst::ICMP_EQ;
1608 if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1) &&
1609 !isa<BlockAddress>(V1)) {
1610 if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2) &&
1611 !isa<BlockAddress>(V2)) {
1612 // We distilled this down to a simple case, use the standard constant
1615 ICmpInst::Predicate pred = ICmpInst::ICMP_EQ;
1616 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1617 if (R && !R->isZero())
1619 pred = isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1620 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1621 if (R && !R->isZero())
1623 pred = isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1624 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1625 if (R && !R->isZero())
1628 // If we couldn't figure it out, bail.
1629 return ICmpInst::BAD_ICMP_PREDICATE;
1632 // If the first operand is simple, swap operands.
1633 ICmpInst::Predicate SwappedRelation =
1634 evaluateICmpRelation(V2, V1, isSigned);
1635 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1636 return ICmpInst::getSwappedPredicate(SwappedRelation);
1638 } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1)) {
1639 if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1640 ICmpInst::Predicate SwappedRelation =
1641 evaluateICmpRelation(V2, V1, isSigned);
1642 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1643 return ICmpInst::getSwappedPredicate(SwappedRelation);
1644 return ICmpInst::BAD_ICMP_PREDICATE;
1647 // Now we know that the RHS is a GlobalValue, BlockAddress or simple
1648 // constant (which, since the types must match, means that it's a
1649 // ConstantPointerNull).
1650 if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
1651 // Don't try to decide equality of aliases.
1652 if (!isa<GlobalAlias>(GV) && !isa<GlobalAlias>(GV2))
1653 if (!GV->hasExternalWeakLinkage() || !GV2->hasExternalWeakLinkage())
1654 return ICmpInst::ICMP_NE;
1655 } else if (isa<BlockAddress>(V2)) {
1656 return ICmpInst::ICMP_NE; // Globals never equal labels.
1658 assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!");
1659 // GlobalVals can never be null unless they have external weak linkage.
1660 // We don't try to evaluate aliases here.
1661 if (!GV->hasExternalWeakLinkage() && !isa<GlobalAlias>(GV))
1662 return ICmpInst::ICMP_NE;
1664 } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(V1)) {
1665 if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1666 ICmpInst::Predicate SwappedRelation =
1667 evaluateICmpRelation(V2, V1, isSigned);
1668 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1669 return ICmpInst::getSwappedPredicate(SwappedRelation);
1670 return ICmpInst::BAD_ICMP_PREDICATE;
1673 // Now we know that the RHS is a GlobalValue, BlockAddress or simple
1674 // constant (which, since the types must match, means that it is a
1675 // ConstantPointerNull).
1676 if (const BlockAddress *BA2 = dyn_cast<BlockAddress>(V2)) {
1677 // Block address in another function can't equal this one, but block
1678 // addresses in the current function might be the same if blocks are
1680 if (BA2->getFunction() != BA->getFunction())
1681 return ICmpInst::ICMP_NE;
1683 // Block addresses aren't null, don't equal the address of globals.
1684 assert((isa<ConstantPointerNull>(V2) || isa<GlobalValue>(V2)) &&
1685 "Canonicalization guarantee!");
1686 return ICmpInst::ICMP_NE;
1689 // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1690 // constantexpr, a global, block address, or a simple constant.
1691 ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1692 Constant *CE1Op0 = CE1->getOperand(0);
1694 switch (CE1->getOpcode()) {
1695 case Instruction::Trunc:
1696 case Instruction::FPTrunc:
1697 case Instruction::FPExt:
1698 case Instruction::FPToUI:
1699 case Instruction::FPToSI:
1700 break; // We can't evaluate floating point casts or truncations.
1702 case Instruction::UIToFP:
1703 case Instruction::SIToFP:
1704 case Instruction::BitCast:
1705 case Instruction::ZExt:
1706 case Instruction::SExt:
1707 // If the cast is not actually changing bits, and the second operand is a
1708 // null pointer, do the comparison with the pre-casted value.
1709 if (V2->isNullValue() &&
1710 (CE1->getType()->isPointerTy() || CE1->getType()->isIntegerTy())) {
1711 if (CE1->getOpcode() == Instruction::ZExt) isSigned = false;
1712 if (CE1->getOpcode() == Instruction::SExt) isSigned = true;
1713 return evaluateICmpRelation(CE1Op0,
1714 Constant::getNullValue(CE1Op0->getType()),
1719 case Instruction::GetElementPtr:
1720 // Ok, since this is a getelementptr, we know that the constant has a
1721 // pointer type. Check the various cases.
1722 if (isa<ConstantPointerNull>(V2)) {
1723 // If we are comparing a GEP to a null pointer, check to see if the base
1724 // of the GEP equals the null pointer.
1725 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1726 if (GV->hasExternalWeakLinkage())
1727 // Weak linkage GVals could be zero or not. We're comparing that
1728 // to null pointer so its greater-or-equal
1729 return isSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE;
1731 // If its not weak linkage, the GVal must have a non-zero address
1732 // so the result is greater-than
1733 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1734 } else if (isa<ConstantPointerNull>(CE1Op0)) {
1735 // If we are indexing from a null pointer, check to see if we have any
1736 // non-zero indices.
1737 for (unsigned i = 1, e = CE1->getNumOperands(); i != e; ++i)
1738 if (!CE1->getOperand(i)->isNullValue())
1739 // Offsetting from null, must not be equal.
1740 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1741 // Only zero indexes from null, must still be zero.
1742 return ICmpInst::ICMP_EQ;
1744 // Otherwise, we can't really say if the first operand is null or not.
1745 } else if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
1746 if (isa<ConstantPointerNull>(CE1Op0)) {
1747 if (GV2->hasExternalWeakLinkage())
1748 // Weak linkage GVals could be zero or not. We're comparing it to
1749 // a null pointer, so its less-or-equal
1750 return isSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE;
1752 // If its not weak linkage, the GVal must have a non-zero address
1753 // so the result is less-than
1754 return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1755 } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1757 // If this is a getelementptr of the same global, then it must be
1758 // different. Because the types must match, the getelementptr could
1759 // only have at most one index, and because we fold getelementptr's
1760 // with a single zero index, it must be nonzero.
1761 assert(CE1->getNumOperands() == 2 &&
1762 !CE1->getOperand(1)->isNullValue() &&
1763 "Surprising getelementptr!");
1764 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1766 // If they are different globals, we don't know what the value is,
1767 // but they can't be equal.
1768 return ICmpInst::ICMP_NE;
1772 ConstantExpr *CE2 = cast<ConstantExpr>(V2);
1773 Constant *CE2Op0 = CE2->getOperand(0);
1775 // There are MANY other foldings that we could perform here. They will
1776 // probably be added on demand, as they seem needed.
1777 switch (CE2->getOpcode()) {
1779 case Instruction::GetElementPtr:
1780 // By far the most common case to handle is when the base pointers are
1781 // obviously to the same or different globals.
1782 if (isa<GlobalValue>(CE1Op0) && isa<GlobalValue>(CE2Op0)) {
1783 if (CE1Op0 != CE2Op0) // Don't know relative ordering, but not equal
1784 return ICmpInst::ICMP_NE;
1785 // Ok, we know that both getelementptr instructions are based on the
1786 // same global. From this, we can precisely determine the relative
1787 // ordering of the resultant pointers.
1790 // The logic below assumes that the result of the comparison
1791 // can be determined by finding the first index that differs.
1792 // This doesn't work if there is over-indexing in any
1793 // subsequent indices, so check for that case first.
1794 if (!CE1->isGEPWithNoNotionalOverIndexing() ||
1795 !CE2->isGEPWithNoNotionalOverIndexing())
1796 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1798 // Compare all of the operands the GEP's have in common.
1799 gep_type_iterator GTI = gep_type_begin(CE1);
1800 for (;i != CE1->getNumOperands() && i != CE2->getNumOperands();
1802 switch (IdxCompare(CE1->getOperand(i),
1803 CE2->getOperand(i), GTI.getIndexedType())) {
1804 case -1: return isSigned ? ICmpInst::ICMP_SLT:ICmpInst::ICMP_ULT;
1805 case 1: return isSigned ? ICmpInst::ICMP_SGT:ICmpInst::ICMP_UGT;
1806 case -2: return ICmpInst::BAD_ICMP_PREDICATE;
1809 // Ok, we ran out of things they have in common. If any leftovers
1810 // are non-zero then we have a difference, otherwise we are equal.
1811 for (; i < CE1->getNumOperands(); ++i)
1812 if (!CE1->getOperand(i)->isNullValue()) {
1813 if (isa<ConstantInt>(CE1->getOperand(i)))
1814 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1816 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1819 for (; i < CE2->getNumOperands(); ++i)
1820 if (!CE2->getOperand(i)->isNullValue()) {
1821 if (isa<ConstantInt>(CE2->getOperand(i)))
1822 return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1824 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1826 return ICmpInst::ICMP_EQ;
1835 return ICmpInst::BAD_ICMP_PREDICATE;
1838 Constant *llvm::ConstantFoldCompareInstruction(unsigned short pred,
1839 Constant *C1, Constant *C2) {
1841 if (VectorType *VT = dyn_cast<VectorType>(C1->getType()))
1842 ResultTy = VectorType::get(Type::getInt1Ty(C1->getContext()),
1843 VT->getNumElements());
1845 ResultTy = Type::getInt1Ty(C1->getContext());
1847 // Fold FCMP_FALSE/FCMP_TRUE unconditionally.
1848 if (pred == FCmpInst::FCMP_FALSE)
1849 return Constant::getNullValue(ResultTy);
1851 if (pred == FCmpInst::FCMP_TRUE)
1852 return Constant::getAllOnesValue(ResultTy);
1854 // Handle some degenerate cases first
1855 if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
1856 // For EQ and NE, we can always pick a value for the undef to make the
1857 // predicate pass or fail, so we can return undef.
1858 // Also, if both operands are undef, we can return undef.
1859 if (ICmpInst::isEquality(ICmpInst::Predicate(pred)) ||
1860 (isa<UndefValue>(C1) && isa<UndefValue>(C2)))
1861 return UndefValue::get(ResultTy);
1862 // Otherwise, pick the same value as the non-undef operand, and fold
1863 // it to true or false.
1864 return ConstantInt::get(ResultTy, CmpInst::isTrueWhenEqual(pred));
1867 // No compile-time operations on this type yet.
1868 if (C1->getType()->isPPC_FP128Ty())
1871 // icmp eq/ne(null,GV) -> false/true
1872 if (C1->isNullValue()) {
1873 if (const GlobalValue *GV = dyn_cast<GlobalValue>(C2))
1874 // Don't try to evaluate aliases. External weak GV can be null.
1875 if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
1876 if (pred == ICmpInst::ICMP_EQ)
1877 return ConstantInt::getFalse(C1->getContext());
1878 else if (pred == ICmpInst::ICMP_NE)
1879 return ConstantInt::getTrue(C1->getContext());
1881 // icmp eq/ne(GV,null) -> false/true
1882 } else if (C2->isNullValue()) {
1883 if (const GlobalValue *GV = dyn_cast<GlobalValue>(C1))
1884 // Don't try to evaluate aliases. External weak GV can be null.
1885 if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
1886 if (pred == ICmpInst::ICMP_EQ)
1887 return ConstantInt::getFalse(C1->getContext());
1888 else if (pred == ICmpInst::ICMP_NE)
1889 return ConstantInt::getTrue(C1->getContext());
1893 // If the comparison is a comparison between two i1's, simplify it.
1894 if (C1->getType()->isIntegerTy(1)) {
1896 case ICmpInst::ICMP_EQ:
1897 if (isa<ConstantInt>(C2))
1898 return ConstantExpr::getXor(C1, ConstantExpr::getNot(C2));
1899 return ConstantExpr::getXor(ConstantExpr::getNot(C1), C2);
1900 case ICmpInst::ICMP_NE:
1901 return ConstantExpr::getXor(C1, C2);
1907 if (isa<ConstantInt>(C1) && isa<ConstantInt>(C2)) {
1908 APInt V1 = cast<ConstantInt>(C1)->getValue();
1909 APInt V2 = cast<ConstantInt>(C2)->getValue();
1911 default: llvm_unreachable("Invalid ICmp Predicate"); return 0;
1912 case ICmpInst::ICMP_EQ: return ConstantInt::get(ResultTy, V1 == V2);
1913 case ICmpInst::ICMP_NE: return ConstantInt::get(ResultTy, V1 != V2);
1914 case ICmpInst::ICMP_SLT: return ConstantInt::get(ResultTy, V1.slt(V2));
1915 case ICmpInst::ICMP_SGT: return ConstantInt::get(ResultTy, V1.sgt(V2));
1916 case ICmpInst::ICMP_SLE: return ConstantInt::get(ResultTy, V1.sle(V2));
1917 case ICmpInst::ICMP_SGE: return ConstantInt::get(ResultTy, V1.sge(V2));
1918 case ICmpInst::ICMP_ULT: return ConstantInt::get(ResultTy, V1.ult(V2));
1919 case ICmpInst::ICMP_UGT: return ConstantInt::get(ResultTy, V1.ugt(V2));
1920 case ICmpInst::ICMP_ULE: return ConstantInt::get(ResultTy, V1.ule(V2));
1921 case ICmpInst::ICMP_UGE: return ConstantInt::get(ResultTy, V1.uge(V2));
1923 } else if (isa<ConstantFP>(C1) && isa<ConstantFP>(C2)) {
1924 APFloat C1V = cast<ConstantFP>(C1)->getValueAPF();
1925 APFloat C2V = cast<ConstantFP>(C2)->getValueAPF();
1926 APFloat::cmpResult R = C1V.compare(C2V);
1928 default: llvm_unreachable("Invalid FCmp Predicate"); return 0;
1929 case FCmpInst::FCMP_FALSE: return Constant::getNullValue(ResultTy);
1930 case FCmpInst::FCMP_TRUE: return Constant::getAllOnesValue(ResultTy);
1931 case FCmpInst::FCMP_UNO:
1932 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered);
1933 case FCmpInst::FCMP_ORD:
1934 return ConstantInt::get(ResultTy, R!=APFloat::cmpUnordered);
1935 case FCmpInst::FCMP_UEQ:
1936 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1937 R==APFloat::cmpEqual);
1938 case FCmpInst::FCMP_OEQ:
1939 return ConstantInt::get(ResultTy, R==APFloat::cmpEqual);
1940 case FCmpInst::FCMP_UNE:
1941 return ConstantInt::get(ResultTy, R!=APFloat::cmpEqual);
1942 case FCmpInst::FCMP_ONE:
1943 return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
1944 R==APFloat::cmpGreaterThan);
1945 case FCmpInst::FCMP_ULT:
1946 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1947 R==APFloat::cmpLessThan);
1948 case FCmpInst::FCMP_OLT:
1949 return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan);
1950 case FCmpInst::FCMP_UGT:
1951 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1952 R==APFloat::cmpGreaterThan);
1953 case FCmpInst::FCMP_OGT:
1954 return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan);
1955 case FCmpInst::FCMP_ULE:
1956 return ConstantInt::get(ResultTy, R!=APFloat::cmpGreaterThan);
1957 case FCmpInst::FCMP_OLE:
1958 return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
1959 R==APFloat::cmpEqual);
1960 case FCmpInst::FCMP_UGE:
1961 return ConstantInt::get(ResultTy, R!=APFloat::cmpLessThan);
1962 case FCmpInst::FCMP_OGE:
1963 return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan ||
1964 R==APFloat::cmpEqual);
1966 } else if (C1->getType()->isVectorTy()) {
1967 SmallVector<Constant*, 16> C1Elts, C2Elts;
1968 C1->getVectorElements(C1Elts);
1969 C2->getVectorElements(C2Elts);
1970 if (C1Elts.empty() || C2Elts.empty())
1973 // If we can constant fold the comparison of each element, constant fold
1974 // the whole vector comparison.
1975 SmallVector<Constant*, 4> ResElts;
1976 // Compare the elements, producing an i1 result or constant expr.
1977 for (unsigned i = 0, e = C1Elts.size(); i != e; ++i)
1978 ResElts.push_back(ConstantExpr::getCompare(pred, C1Elts[i], C2Elts[i]));
1980 return ConstantVector::get(ResElts);
1983 if (C1->getType()->isFloatingPointTy()) {
1984 int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
1985 switch (evaluateFCmpRelation(C1, C2)) {
1986 default: llvm_unreachable("Unknown relation!");
1987 case FCmpInst::FCMP_UNO:
1988 case FCmpInst::FCMP_ORD:
1989 case FCmpInst::FCMP_UEQ:
1990 case FCmpInst::FCMP_UNE:
1991 case FCmpInst::FCMP_ULT:
1992 case FCmpInst::FCMP_UGT:
1993 case FCmpInst::FCMP_ULE:
1994 case FCmpInst::FCMP_UGE:
1995 case FCmpInst::FCMP_TRUE:
1996 case FCmpInst::FCMP_FALSE:
1997 case FCmpInst::BAD_FCMP_PREDICATE:
1998 break; // Couldn't determine anything about these constants.
1999 case FCmpInst::FCMP_OEQ: // We know that C1 == C2
2000 Result = (pred == FCmpInst::FCMP_UEQ || pred == FCmpInst::FCMP_OEQ ||
2001 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE ||
2002 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
2004 case FCmpInst::FCMP_OLT: // We know that C1 < C2
2005 Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
2006 pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT ||
2007 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE);
2009 case FCmpInst::FCMP_OGT: // We know that C1 > C2
2010 Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
2011 pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT ||
2012 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
2014 case FCmpInst::FCMP_OLE: // We know that C1 <= C2
2015 // We can only partially decide this relation.
2016 if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
2018 else if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
2021 case FCmpInst::FCMP_OGE: // We known that C1 >= C2
2022 // We can only partially decide this relation.
2023 if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
2025 else if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
2028 case FCmpInst::FCMP_ONE: // We know that C1 != C2
2029 // We can only partially decide this relation.
2030 if (pred == FCmpInst::FCMP_OEQ || pred == FCmpInst::FCMP_UEQ)
2032 else if (pred == FCmpInst::FCMP_ONE || pred == FCmpInst::FCMP_UNE)
2037 // If we evaluated the result, return it now.
2039 return ConstantInt::get(ResultTy, Result);
2042 // Evaluate the relation between the two constants, per the predicate.
2043 int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
2044 switch (evaluateICmpRelation(C1, C2, CmpInst::isSigned(pred))) {
2045 default: llvm_unreachable("Unknown relational!");
2046 case ICmpInst::BAD_ICMP_PREDICATE:
2047 break; // Couldn't determine anything about these constants.
2048 case ICmpInst::ICMP_EQ: // We know the constants are equal!
2049 // If we know the constants are equal, we can decide the result of this
2050 // computation precisely.
2051 Result = ICmpInst::isTrueWhenEqual((ICmpInst::Predicate)pred);
2053 case ICmpInst::ICMP_ULT:
2055 case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_ULE:
2057 case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_UGE:
2061 case ICmpInst::ICMP_SLT:
2063 case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SLE:
2065 case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SGE:
2069 case ICmpInst::ICMP_UGT:
2071 case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_UGE:
2073 case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_ULE:
2077 case ICmpInst::ICMP_SGT:
2079 case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SGE:
2081 case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SLE:
2085 case ICmpInst::ICMP_ULE:
2086 if (pred == ICmpInst::ICMP_UGT) Result = 0;
2087 if (pred == ICmpInst::ICMP_ULT || pred == ICmpInst::ICMP_ULE) Result = 1;
2089 case ICmpInst::ICMP_SLE:
2090 if (pred == ICmpInst::ICMP_SGT) Result = 0;
2091 if (pred == ICmpInst::ICMP_SLT || pred == ICmpInst::ICMP_SLE) Result = 1;
2093 case ICmpInst::ICMP_UGE:
2094 if (pred == ICmpInst::ICMP_ULT) Result = 0;
2095 if (pred == ICmpInst::ICMP_UGT || pred == ICmpInst::ICMP_UGE) Result = 1;
2097 case ICmpInst::ICMP_SGE:
2098 if (pred == ICmpInst::ICMP_SLT) Result = 0;
2099 if (pred == ICmpInst::ICMP_SGT || pred == ICmpInst::ICMP_SGE) Result = 1;
2101 case ICmpInst::ICMP_NE:
2102 if (pred == ICmpInst::ICMP_EQ) Result = 0;
2103 if (pred == ICmpInst::ICMP_NE) Result = 1;
2107 // If we evaluated the result, return it now.
2109 return ConstantInt::get(ResultTy, Result);
2111 // If the right hand side is a bitcast, try using its inverse to simplify
2112 // it by moving it to the left hand side. We can't do this if it would turn
2113 // a vector compare into a scalar compare or visa versa.
2114 if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(C2)) {
2115 Constant *CE2Op0 = CE2->getOperand(0);
2116 if (CE2->getOpcode() == Instruction::BitCast &&
2117 CE2->getType()->isVectorTy() == CE2Op0->getType()->isVectorTy()) {
2118 Constant *Inverse = ConstantExpr::getBitCast(C1, CE2Op0->getType());
2119 return ConstantExpr::getICmp(pred, Inverse, CE2Op0);
2123 // If the left hand side is an extension, try eliminating it.
2124 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
2125 if ((CE1->getOpcode() == Instruction::SExt && ICmpInst::isSigned(pred)) ||
2126 (CE1->getOpcode() == Instruction::ZExt && !ICmpInst::isSigned(pred))){
2127 Constant *CE1Op0 = CE1->getOperand(0);
2128 Constant *CE1Inverse = ConstantExpr::getTrunc(CE1, CE1Op0->getType());
2129 if (CE1Inverse == CE1Op0) {
2130 // Check whether we can safely truncate the right hand side.
2131 Constant *C2Inverse = ConstantExpr::getTrunc(C2, CE1Op0->getType());
2132 if (ConstantExpr::getZExt(C2Inverse, C2->getType()) == C2) {
2133 return ConstantExpr::getICmp(pred, CE1Inverse, C2Inverse);
2139 if ((!isa<ConstantExpr>(C1) && isa<ConstantExpr>(C2)) ||
2140 (C1->isNullValue() && !C2->isNullValue())) {
2141 // If C2 is a constant expr and C1 isn't, flip them around and fold the
2142 // other way if possible.
2143 // Also, if C1 is null and C2 isn't, flip them around.
2144 pred = ICmpInst::getSwappedPredicate((ICmpInst::Predicate)pred);
2145 return ConstantExpr::getICmp(pred, C2, C1);
2151 /// isInBoundsIndices - Test whether the given sequence of *normalized* indices
2153 template<typename IndexTy>
2154 static bool isInBoundsIndices(ArrayRef<IndexTy> Idxs) {
2155 // No indices means nothing that could be out of bounds.
2156 if (Idxs.empty()) return true;
2158 // If the first index is zero, it's in bounds.
2159 if (cast<Constant>(Idxs[0])->isNullValue()) return true;
2161 // If the first index is one and all the rest are zero, it's in bounds,
2162 // by the one-past-the-end rule.
2163 if (!cast<ConstantInt>(Idxs[0])->isOne())
2165 for (unsigned i = 1, e = Idxs.size(); i != e; ++i)
2166 if (!cast<Constant>(Idxs[i])->isNullValue())
2171 template<typename IndexTy>
2172 static Constant *ConstantFoldGetElementPtrImpl(Constant *C,
2174 ArrayRef<IndexTy> Idxs) {
2175 if (Idxs.empty()) return C;
2176 Constant *Idx0 = cast<Constant>(Idxs[0]);
2177 if ((Idxs.size() == 1 && Idx0->isNullValue()))
2180 if (isa<UndefValue>(C)) {
2181 PointerType *Ptr = cast<PointerType>(C->getType());
2182 Type *Ty = GetElementPtrInst::getIndexedType(Ptr, Idxs);
2183 assert(Ty != 0 && "Invalid indices for GEP!");
2184 return UndefValue::get(PointerType::get(Ty, Ptr->getAddressSpace()));
2187 if (C->isNullValue()) {
2189 for (unsigned i = 0, e = Idxs.size(); i != e; ++i)
2190 if (!cast<Constant>(Idxs[i])->isNullValue()) {
2195 PointerType *Ptr = cast<PointerType>(C->getType());
2196 Type *Ty = GetElementPtrInst::getIndexedType(Ptr, Idxs);
2197 assert(Ty != 0 && "Invalid indices for GEP!");
2198 return ConstantPointerNull::get(PointerType::get(Ty,
2199 Ptr->getAddressSpace()));
2203 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2204 // Combine Indices - If the source pointer to this getelementptr instruction
2205 // is a getelementptr instruction, combine the indices of the two
2206 // getelementptr instructions into a single instruction.
2208 if (CE->getOpcode() == Instruction::GetElementPtr) {
2210 for (gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
2214 if ((LastTy && isa<SequentialType>(LastTy)) || Idx0->isNullValue()) {
2215 SmallVector<Value*, 16> NewIndices;
2216 NewIndices.reserve(Idxs.size() + CE->getNumOperands());
2217 for (unsigned i = 1, e = CE->getNumOperands()-1; i != e; ++i)
2218 NewIndices.push_back(CE->getOperand(i));
2220 // Add the last index of the source with the first index of the new GEP.
2221 // Make sure to handle the case when they are actually different types.
2222 Constant *Combined = CE->getOperand(CE->getNumOperands()-1);
2223 // Otherwise it must be an array.
2224 if (!Idx0->isNullValue()) {
2225 Type *IdxTy = Combined->getType();
2226 if (IdxTy != Idx0->getType()) {
2227 Type *Int64Ty = Type::getInt64Ty(IdxTy->getContext());
2228 Constant *C1 = ConstantExpr::getSExtOrBitCast(Idx0, Int64Ty);
2229 Constant *C2 = ConstantExpr::getSExtOrBitCast(Combined, Int64Ty);
2230 Combined = ConstantExpr::get(Instruction::Add, C1, C2);
2233 ConstantExpr::get(Instruction::Add, Idx0, Combined);
2237 NewIndices.push_back(Combined);
2238 NewIndices.append(Idxs.begin() + 1, Idxs.end());
2240 ConstantExpr::getGetElementPtr(CE->getOperand(0), NewIndices,
2242 cast<GEPOperator>(CE)->isInBounds());
2246 // Implement folding of:
2247 // i32* getelementptr ([2 x i32]* bitcast ([3 x i32]* %X to [2 x i32]*),
2249 // To: i32* getelementptr ([3 x i32]* %X, i64 0, i64 0)
2251 if (CE->isCast() && Idxs.size() > 1 && Idx0->isNullValue()) {
2252 if (PointerType *SPT =
2253 dyn_cast<PointerType>(CE->getOperand(0)->getType()))
2254 if (ArrayType *SAT = dyn_cast<ArrayType>(SPT->getElementType()))
2255 if (ArrayType *CAT =
2256 dyn_cast<ArrayType>(cast<PointerType>(C->getType())->getElementType()))
2257 if (CAT->getElementType() == SAT->getElementType())
2259 ConstantExpr::getGetElementPtr((Constant*)CE->getOperand(0),
2264 // Check to see if any array indices are not within the corresponding
2265 // notional array bounds. If so, try to determine if they can be factored
2266 // out into preceding dimensions.
2267 bool Unknown = false;
2268 SmallVector<Constant *, 8> NewIdxs;
2269 Type *Ty = C->getType();
2271 for (unsigned i = 0, e = Idxs.size(); i != e;
2272 Prev = Ty, Ty = cast<CompositeType>(Ty)->getTypeAtIndex(Idxs[i]), ++i) {
2273 if (ConstantInt *CI = dyn_cast<ConstantInt>(Idxs[i])) {
2274 if (ArrayType *ATy = dyn_cast<ArrayType>(Ty))
2275 if (ATy->getNumElements() <= INT64_MAX &&
2276 ATy->getNumElements() != 0 &&
2277 CI->getSExtValue() >= (int64_t)ATy->getNumElements()) {
2278 if (isa<SequentialType>(Prev)) {
2279 // It's out of range, but we can factor it into the prior
2281 NewIdxs.resize(Idxs.size());
2282 ConstantInt *Factor = ConstantInt::get(CI->getType(),
2283 ATy->getNumElements());
2284 NewIdxs[i] = ConstantExpr::getSRem(CI, Factor);
2286 Constant *PrevIdx = cast<Constant>(Idxs[i-1]);
2287 Constant *Div = ConstantExpr::getSDiv(CI, Factor);
2289 // Before adding, extend both operands to i64 to avoid
2290 // overflow trouble.
2291 if (!PrevIdx->getType()->isIntegerTy(64))
2292 PrevIdx = ConstantExpr::getSExt(PrevIdx,
2293 Type::getInt64Ty(Div->getContext()));
2294 if (!Div->getType()->isIntegerTy(64))
2295 Div = ConstantExpr::getSExt(Div,
2296 Type::getInt64Ty(Div->getContext()));
2298 NewIdxs[i-1] = ConstantExpr::getAdd(PrevIdx, Div);
2300 // It's out of range, but the prior dimension is a struct
2301 // so we can't do anything about it.
2306 // We don't know if it's in range or not.
2311 // If we did any factoring, start over with the adjusted indices.
2312 if (!NewIdxs.empty()) {
2313 for (unsigned i = 0, e = Idxs.size(); i != e; ++i)
2314 if (!NewIdxs[i]) NewIdxs[i] = cast<Constant>(Idxs[i]);
2315 return ConstantExpr::getGetElementPtr(C, NewIdxs, inBounds);
2318 // If all indices are known integers and normalized, we can do a simple
2319 // check for the "inbounds" property.
2320 if (!Unknown && !inBounds &&
2321 isa<GlobalVariable>(C) && isInBoundsIndices(Idxs))
2322 return ConstantExpr::getInBoundsGetElementPtr(C, Idxs);
2327 Constant *llvm::ConstantFoldGetElementPtr(Constant *C,
2329 ArrayRef<Constant *> Idxs) {
2330 return ConstantFoldGetElementPtrImpl(C, inBounds, Idxs);
2333 Constant *llvm::ConstantFoldGetElementPtr(Constant *C,
2335 ArrayRef<Value *> Idxs) {
2336 return ConstantFoldGetElementPtrImpl(C, inBounds, Idxs);