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 SmallVector<Value*, 8> IdxList;
110 Constant::getNullValue(Type::getInt32Ty(DPTy->getContext()));
111 IdxList.push_back(Zero);
112 Type *ElTy = PTy->getElementType();
113 while (ElTy != DPTy->getElementType()) {
114 if (StructType *STy = dyn_cast<StructType>(ElTy)) {
115 if (STy->getNumElements() == 0) break;
116 ElTy = STy->getElementType(0);
117 IdxList.push_back(Zero);
118 } else if (SequentialType *STy =
119 dyn_cast<SequentialType>(ElTy)) {
120 if (ElTy->isPointerTy()) break; // Can't index into pointers!
121 ElTy = STy->getElementType();
122 IdxList.push_back(Zero);
128 if (ElTy == DPTy->getElementType())
129 // This GEP is inbounds because all indices are zero.
130 return ConstantExpr::getInBoundsGetElementPtr(V, IdxList);
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 (VectorType *DestPTy = dyn_cast<VectorType>(DestTy)) {
136 if (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(Type *Ty, Type *DestTy,
336 if (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 (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 (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(Type *Ty, 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 (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
396 Constant *C = ConstantExpr::getAlignOf(ATy->getElementType());
397 C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
404 if (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 (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(Type *Ty, Constant *FieldNo,
460 if (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 (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,
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 VectorType *DestVecTy = cast<VectorType>(DestTy);
557 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(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, 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 (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 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 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>(Cond)) {
733 if (isa<UndefValue>(V1)) return V1;
736 if (isa<UndefValue>(V1)) return V2;
737 if (isa<UndefValue>(V2)) return V1;
738 if (V1 == V2) return V1;
740 if (ConstantExpr *TrueVal = dyn_cast<ConstantExpr>(V1)) {
741 if (TrueVal->getOpcode() == Instruction::Select)
742 if (TrueVal->getOperand(0) == Cond)
743 return ConstantExpr::getSelect(Cond, TrueVal->getOperand(1), V2);
745 if (ConstantExpr *FalseVal = dyn_cast<ConstantExpr>(V2)) {
746 if (FalseVal->getOpcode() == Instruction::Select)
747 if (FalseVal->getOperand(0) == Cond)
748 return ConstantExpr::getSelect(Cond, V1, FalseVal->getOperand(2));
754 Constant *llvm::ConstantFoldExtractElementInstruction(Constant *Val,
756 if (isa<UndefValue>(Val)) // ee(undef, x) -> undef
757 return UndefValue::get(cast<VectorType>(Val->getType())->getElementType());
758 if (Val->isNullValue()) // ee(zero, x) -> zero
759 return Constant::getNullValue(
760 cast<VectorType>(Val->getType())->getElementType());
762 if (ConstantVector *CVal = dyn_cast<ConstantVector>(Val)) {
763 if (ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx)) {
764 return CVal->getOperand(CIdx->getZExtValue());
765 } else if (isa<UndefValue>(Idx)) {
766 // ee({w,x,y,z}, undef) -> w (an arbitrary value).
767 return CVal->getOperand(0);
773 Constant *llvm::ConstantFoldInsertElementInstruction(Constant *Val,
776 ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx);
778 APInt idxVal = CIdx->getValue();
779 if (isa<UndefValue>(Val)) {
780 // Insertion of scalar constant into vector undef
781 // Optimize away insertion of undef
782 if (isa<UndefValue>(Elt))
784 // Otherwise break the aggregate undef into multiple undefs and do
787 cast<VectorType>(Val->getType())->getNumElements();
788 std::vector<Constant*> Ops;
790 for (unsigned i = 0; i < numOps; ++i) {
792 (idxVal == i) ? Elt : UndefValue::get(Elt->getType());
795 return ConstantVector::get(Ops);
797 if (isa<ConstantAggregateZero>(Val)) {
798 // Insertion of scalar constant into vector aggregate zero
799 // Optimize away insertion of zero
800 if (Elt->isNullValue())
802 // Otherwise break the aggregate zero into multiple zeros and do
805 cast<VectorType>(Val->getType())->getNumElements();
806 std::vector<Constant*> Ops;
808 for (unsigned i = 0; i < numOps; ++i) {
810 (idxVal == i) ? Elt : Constant::getNullValue(Elt->getType());
813 return ConstantVector::get(Ops);
815 if (ConstantVector *CVal = dyn_cast<ConstantVector>(Val)) {
816 // Insertion of scalar constant into vector constant
817 std::vector<Constant*> Ops;
818 Ops.reserve(CVal->getNumOperands());
819 for (unsigned i = 0; i < CVal->getNumOperands(); ++i) {
821 (idxVal == i) ? Elt : cast<Constant>(CVal->getOperand(i));
824 return ConstantVector::get(Ops);
830 /// GetVectorElement - If C is a ConstantVector, ConstantAggregateZero or Undef
831 /// return the specified element value. Otherwise return null.
832 static Constant *GetVectorElement(Constant *C, unsigned EltNo) {
833 if (ConstantVector *CV = dyn_cast<ConstantVector>(C))
834 return CV->getOperand(EltNo);
836 Type *EltTy = cast<VectorType>(C->getType())->getElementType();
837 if (isa<ConstantAggregateZero>(C))
838 return Constant::getNullValue(EltTy);
839 if (isa<UndefValue>(C))
840 return UndefValue::get(EltTy);
844 Constant *llvm::ConstantFoldShuffleVectorInstruction(Constant *V1,
847 // Undefined shuffle mask -> undefined value.
848 if (isa<UndefValue>(Mask)) return UndefValue::get(V1->getType());
850 unsigned MaskNumElts = cast<VectorType>(Mask->getType())->getNumElements();
851 unsigned SrcNumElts = cast<VectorType>(V1->getType())->getNumElements();
852 Type *EltTy = cast<VectorType>(V1->getType())->getElementType();
854 // Loop over the shuffle mask, evaluating each element.
855 SmallVector<Constant*, 32> Result;
856 for (unsigned i = 0; i != MaskNumElts; ++i) {
857 Constant *InElt = GetVectorElement(Mask, i);
858 if (InElt == 0) return 0;
860 if (isa<UndefValue>(InElt))
861 InElt = UndefValue::get(EltTy);
862 else if (ConstantInt *CI = dyn_cast<ConstantInt>(InElt)) {
863 unsigned Elt = CI->getZExtValue();
864 if (Elt >= SrcNumElts*2)
865 InElt = UndefValue::get(EltTy);
866 else if (Elt >= SrcNumElts)
867 InElt = GetVectorElement(V2, Elt - SrcNumElts);
869 InElt = GetVectorElement(V1, Elt);
870 if (InElt == 0) return 0;
875 Result.push_back(InElt);
878 return ConstantVector::get(Result);
881 Constant *llvm::ConstantFoldExtractValueInstruction(Constant *Agg,
882 ArrayRef<unsigned> Idxs) {
883 // Base case: no indices, so return the entire value.
887 if (isa<UndefValue>(Agg)) // ev(undef, x) -> undef
888 return UndefValue::get(ExtractValueInst::getIndexedType(Agg->getType(),
891 if (isa<ConstantAggregateZero>(Agg)) // ev(0, x) -> 0
893 Constant::getNullValue(ExtractValueInst::getIndexedType(Agg->getType(),
896 // Otherwise recurse.
897 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(Agg))
898 return ConstantFoldExtractValueInstruction(CS->getOperand(Idxs[0]),
901 if (ConstantArray *CA = dyn_cast<ConstantArray>(Agg))
902 return ConstantFoldExtractValueInstruction(CA->getOperand(Idxs[0]),
904 ConstantVector *CV = cast<ConstantVector>(Agg);
905 return ConstantFoldExtractValueInstruction(CV->getOperand(Idxs[0]),
909 Constant *llvm::ConstantFoldInsertValueInstruction(Constant *Agg,
911 ArrayRef<unsigned> Idxs) {
912 // Base case: no indices, so replace the entire value.
916 if (isa<UndefValue>(Agg)) {
917 // Insertion of constant into aggregate undef
918 // Optimize away insertion of undef.
919 if (isa<UndefValue>(Val))
922 // Otherwise break the aggregate undef into multiple undefs and do
924 CompositeType *AggTy = cast<CompositeType>(Agg->getType());
926 if (ArrayType *AR = dyn_cast<ArrayType>(AggTy))
927 numOps = AR->getNumElements();
929 numOps = cast<StructType>(AggTy)->getNumElements();
931 std::vector<Constant*> Ops(numOps);
932 for (unsigned i = 0; i < numOps; ++i) {
933 Type *MemberTy = AggTy->getTypeAtIndex(i);
936 ConstantFoldInsertValueInstruction(UndefValue::get(MemberTy),
937 Val, Idxs.slice(1)) :
938 UndefValue::get(MemberTy);
942 if (StructType* ST = dyn_cast<StructType>(AggTy))
943 return ConstantStruct::get(ST, Ops);
944 return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
947 if (isa<ConstantAggregateZero>(Agg)) {
948 // Insertion of constant into aggregate zero
949 // Optimize away insertion of zero.
950 if (Val->isNullValue())
953 // Otherwise break the aggregate zero into multiple zeros and do
955 CompositeType *AggTy = cast<CompositeType>(Agg->getType());
957 if (ArrayType *AR = dyn_cast<ArrayType>(AggTy))
958 numOps = AR->getNumElements();
960 numOps = cast<StructType>(AggTy)->getNumElements();
962 std::vector<Constant*> Ops(numOps);
963 for (unsigned i = 0; i < numOps; ++i) {
964 Type *MemberTy = AggTy->getTypeAtIndex(i);
967 ConstantFoldInsertValueInstruction(Constant::getNullValue(MemberTy),
968 Val, Idxs.slice(1)) :
969 Constant::getNullValue(MemberTy);
973 if (StructType *ST = dyn_cast<StructType>(AggTy))
974 return ConstantStruct::get(ST, Ops);
975 return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
978 if (isa<ConstantStruct>(Agg) || isa<ConstantArray>(Agg)) {
979 // Insertion of constant into aggregate constant.
980 std::vector<Constant*> Ops(Agg->getNumOperands());
981 for (unsigned i = 0; i < Agg->getNumOperands(); ++i) {
982 Constant *Op = cast<Constant>(Agg->getOperand(i));
984 Op = ConstantFoldInsertValueInstruction(Op, Val, Idxs.slice(1));
988 if (StructType* ST = dyn_cast<StructType>(Agg->getType()))
989 return ConstantStruct::get(ST, Ops);
990 return ConstantArray::get(cast<ArrayType>(Agg->getType()), Ops);
997 Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
998 Constant *C1, Constant *C2) {
999 // No compile-time operations on this type yet.
1000 if (C1->getType()->isPPC_FP128Ty())
1003 // Handle UndefValue up front.
1004 if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
1006 case Instruction::Xor:
1007 if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
1008 // Handle undef ^ undef -> 0 special case. This is a common
1010 return Constant::getNullValue(C1->getType());
1012 case Instruction::Add:
1013 case Instruction::Sub:
1014 return UndefValue::get(C1->getType());
1015 case Instruction::And:
1016 if (isa<UndefValue>(C1) && isa<UndefValue>(C2)) // undef & undef -> undef
1018 return Constant::getNullValue(C1->getType()); // undef & X -> 0
1019 case Instruction::Mul: {
1021 // X * undef -> undef if X is odd or undef
1022 if (((CI = dyn_cast<ConstantInt>(C1)) && CI->getValue()[0]) ||
1023 ((CI = dyn_cast<ConstantInt>(C2)) && CI->getValue()[0]) ||
1024 (isa<UndefValue>(C1) && isa<UndefValue>(C2)))
1025 return UndefValue::get(C1->getType());
1027 // X * undef -> 0 otherwise
1028 return Constant::getNullValue(C1->getType());
1030 case Instruction::UDiv:
1031 case Instruction::SDiv:
1032 // undef / 1 -> undef
1033 if (Opcode == Instruction::UDiv || Opcode == Instruction::SDiv)
1034 if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2))
1038 case Instruction::URem:
1039 case Instruction::SRem:
1040 if (!isa<UndefValue>(C2)) // undef / X -> 0
1041 return Constant::getNullValue(C1->getType());
1042 return C2; // X / undef -> undef
1043 case Instruction::Or: // X | undef -> -1
1044 if (isa<UndefValue>(C1) && isa<UndefValue>(C2)) // undef | undef -> undef
1046 return Constant::getAllOnesValue(C1->getType()); // undef | X -> ~0
1047 case Instruction::LShr:
1048 if (isa<UndefValue>(C2) && isa<UndefValue>(C1))
1049 return C1; // undef lshr undef -> undef
1050 return Constant::getNullValue(C1->getType()); // X lshr undef -> 0
1051 // undef lshr X -> 0
1052 case Instruction::AShr:
1053 if (!isa<UndefValue>(C2)) // undef ashr X --> all ones
1054 return Constant::getAllOnesValue(C1->getType());
1055 else if (isa<UndefValue>(C1))
1056 return C1; // undef ashr undef -> undef
1058 return C1; // X ashr undef --> X
1059 case Instruction::Shl:
1060 if (isa<UndefValue>(C2) && isa<UndefValue>(C1))
1061 return C1; // undef shl undef -> undef
1062 // undef << X -> 0 or X << undef -> 0
1063 return Constant::getNullValue(C1->getType());
1067 // Handle simplifications when the RHS is a constant int.
1068 if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
1070 case Instruction::Add:
1071 if (CI2->equalsInt(0)) return C1; // X + 0 == X
1073 case Instruction::Sub:
1074 if (CI2->equalsInt(0)) return C1; // X - 0 == X
1076 case Instruction::Mul:
1077 if (CI2->equalsInt(0)) return C2; // X * 0 == 0
1078 if (CI2->equalsInt(1))
1079 return C1; // X * 1 == X
1081 case Instruction::UDiv:
1082 case Instruction::SDiv:
1083 if (CI2->equalsInt(1))
1084 return C1; // X / 1 == X
1085 if (CI2->equalsInt(0))
1086 return UndefValue::get(CI2->getType()); // X / 0 == undef
1088 case Instruction::URem:
1089 case Instruction::SRem:
1090 if (CI2->equalsInt(1))
1091 return Constant::getNullValue(CI2->getType()); // X % 1 == 0
1092 if (CI2->equalsInt(0))
1093 return UndefValue::get(CI2->getType()); // X % 0 == undef
1095 case Instruction::And:
1096 if (CI2->isZero()) return C2; // X & 0 == 0
1097 if (CI2->isAllOnesValue())
1098 return C1; // X & -1 == X
1100 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1101 // (zext i32 to i64) & 4294967295 -> (zext i32 to i64)
1102 if (CE1->getOpcode() == Instruction::ZExt) {
1103 unsigned DstWidth = CI2->getType()->getBitWidth();
1105 CE1->getOperand(0)->getType()->getPrimitiveSizeInBits();
1106 APInt PossiblySetBits(APInt::getLowBitsSet(DstWidth, SrcWidth));
1107 if ((PossiblySetBits & CI2->getValue()) == PossiblySetBits)
1111 // If and'ing the address of a global with a constant, fold it.
1112 if (CE1->getOpcode() == Instruction::PtrToInt &&
1113 isa<GlobalValue>(CE1->getOperand(0))) {
1114 GlobalValue *GV = cast<GlobalValue>(CE1->getOperand(0));
1116 // Functions are at least 4-byte aligned.
1117 unsigned GVAlign = GV->getAlignment();
1118 if (isa<Function>(GV))
1119 GVAlign = std::max(GVAlign, 4U);
1122 unsigned DstWidth = CI2->getType()->getBitWidth();
1123 unsigned SrcWidth = std::min(DstWidth, Log2_32(GVAlign));
1124 APInt BitsNotSet(APInt::getLowBitsSet(DstWidth, SrcWidth));
1126 // If checking bits we know are clear, return zero.
1127 if ((CI2->getValue() & BitsNotSet) == CI2->getValue())
1128 return Constant::getNullValue(CI2->getType());
1133 case Instruction::Or:
1134 if (CI2->equalsInt(0)) return C1; // X | 0 == X
1135 if (CI2->isAllOnesValue())
1136 return C2; // X | -1 == -1
1138 case Instruction::Xor:
1139 if (CI2->equalsInt(0)) return C1; // X ^ 0 == X
1141 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1142 switch (CE1->getOpcode()) {
1144 case Instruction::ICmp:
1145 case Instruction::FCmp:
1146 // cmp pred ^ true -> cmp !pred
1147 assert(CI2->equalsInt(1));
1148 CmpInst::Predicate pred = (CmpInst::Predicate)CE1->getPredicate();
1149 pred = CmpInst::getInversePredicate(pred);
1150 return ConstantExpr::getCompare(pred, CE1->getOperand(0),
1151 CE1->getOperand(1));
1155 case Instruction::AShr:
1156 // ashr (zext C to Ty), C2 -> lshr (zext C, CSA), C2
1157 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1))
1158 if (CE1->getOpcode() == Instruction::ZExt) // Top bits known zero.
1159 return ConstantExpr::getLShr(C1, C2);
1162 } else if (isa<ConstantInt>(C1)) {
1163 // If C1 is a ConstantInt and C2 is not, swap the operands.
1164 if (Instruction::isCommutative(Opcode))
1165 return ConstantExpr::get(Opcode, C2, C1);
1168 // At this point we know neither constant is an UndefValue.
1169 if (ConstantInt *CI1 = dyn_cast<ConstantInt>(C1)) {
1170 if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
1171 using namespace APIntOps;
1172 const APInt &C1V = CI1->getValue();
1173 const APInt &C2V = CI2->getValue();
1177 case Instruction::Add:
1178 return ConstantInt::get(CI1->getContext(), C1V + C2V);
1179 case Instruction::Sub:
1180 return ConstantInt::get(CI1->getContext(), C1V - C2V);
1181 case Instruction::Mul:
1182 return ConstantInt::get(CI1->getContext(), C1V * C2V);
1183 case Instruction::UDiv:
1184 assert(!CI2->isNullValue() && "Div by zero handled above");
1185 return ConstantInt::get(CI1->getContext(), C1V.udiv(C2V));
1186 case Instruction::SDiv:
1187 assert(!CI2->isNullValue() && "Div by zero handled above");
1188 if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
1189 return UndefValue::get(CI1->getType()); // MIN_INT / -1 -> undef
1190 return ConstantInt::get(CI1->getContext(), C1V.sdiv(C2V));
1191 case Instruction::URem:
1192 assert(!CI2->isNullValue() && "Div by zero handled above");
1193 return ConstantInt::get(CI1->getContext(), C1V.urem(C2V));
1194 case Instruction::SRem:
1195 assert(!CI2->isNullValue() && "Div by zero handled above");
1196 if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
1197 return UndefValue::get(CI1->getType()); // MIN_INT % -1 -> undef
1198 return ConstantInt::get(CI1->getContext(), C1V.srem(C2V));
1199 case Instruction::And:
1200 return ConstantInt::get(CI1->getContext(), C1V & C2V);
1201 case Instruction::Or:
1202 return ConstantInt::get(CI1->getContext(), C1V | C2V);
1203 case Instruction::Xor:
1204 return ConstantInt::get(CI1->getContext(), C1V ^ C2V);
1205 case Instruction::Shl: {
1206 uint32_t shiftAmt = C2V.getZExtValue();
1207 if (shiftAmt < C1V.getBitWidth())
1208 return ConstantInt::get(CI1->getContext(), C1V.shl(shiftAmt));
1210 return UndefValue::get(C1->getType()); // too big shift is undef
1212 case Instruction::LShr: {
1213 uint32_t shiftAmt = C2V.getZExtValue();
1214 if (shiftAmt < C1V.getBitWidth())
1215 return ConstantInt::get(CI1->getContext(), C1V.lshr(shiftAmt));
1217 return UndefValue::get(C1->getType()); // too big shift is undef
1219 case Instruction::AShr: {
1220 uint32_t shiftAmt = C2V.getZExtValue();
1221 if (shiftAmt < C1V.getBitWidth())
1222 return ConstantInt::get(CI1->getContext(), C1V.ashr(shiftAmt));
1224 return UndefValue::get(C1->getType()); // too big shift is undef
1230 case Instruction::SDiv:
1231 case Instruction::UDiv:
1232 case Instruction::URem:
1233 case Instruction::SRem:
1234 case Instruction::LShr:
1235 case Instruction::AShr:
1236 case Instruction::Shl:
1237 if (CI1->equalsInt(0)) return C1;
1242 } else if (ConstantFP *CFP1 = dyn_cast<ConstantFP>(C1)) {
1243 if (ConstantFP *CFP2 = dyn_cast<ConstantFP>(C2)) {
1244 APFloat C1V = CFP1->getValueAPF();
1245 APFloat C2V = CFP2->getValueAPF();
1246 APFloat C3V = C1V; // copy for modification
1250 case Instruction::FAdd:
1251 (void)C3V.add(C2V, APFloat::rmNearestTiesToEven);
1252 return ConstantFP::get(C1->getContext(), C3V);
1253 case Instruction::FSub:
1254 (void)C3V.subtract(C2V, APFloat::rmNearestTiesToEven);
1255 return ConstantFP::get(C1->getContext(), C3V);
1256 case Instruction::FMul:
1257 (void)C3V.multiply(C2V, APFloat::rmNearestTiesToEven);
1258 return ConstantFP::get(C1->getContext(), C3V);
1259 case Instruction::FDiv:
1260 (void)C3V.divide(C2V, APFloat::rmNearestTiesToEven);
1261 return ConstantFP::get(C1->getContext(), C3V);
1262 case Instruction::FRem:
1263 (void)C3V.mod(C2V, APFloat::rmNearestTiesToEven);
1264 return ConstantFP::get(C1->getContext(), C3V);
1267 } else if (VectorType *VTy = dyn_cast<VectorType>(C1->getType())) {
1268 ConstantVector *CP1 = dyn_cast<ConstantVector>(C1);
1269 ConstantVector *CP2 = dyn_cast<ConstantVector>(C2);
1270 if ((CP1 != NULL || isa<ConstantAggregateZero>(C1)) &&
1271 (CP2 != NULL || isa<ConstantAggregateZero>(C2))) {
1272 std::vector<Constant*> Res;
1273 Type* EltTy = VTy->getElementType();
1279 case Instruction::Add:
1280 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1281 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1282 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1283 Res.push_back(ConstantExpr::getAdd(C1, C2));
1285 return ConstantVector::get(Res);
1286 case Instruction::FAdd:
1287 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1288 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1289 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1290 Res.push_back(ConstantExpr::getFAdd(C1, C2));
1292 return ConstantVector::get(Res);
1293 case Instruction::Sub:
1294 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1295 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1296 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1297 Res.push_back(ConstantExpr::getSub(C1, C2));
1299 return ConstantVector::get(Res);
1300 case Instruction::FSub:
1301 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1302 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1303 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1304 Res.push_back(ConstantExpr::getFSub(C1, C2));
1306 return ConstantVector::get(Res);
1307 case Instruction::Mul:
1308 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1309 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1310 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1311 Res.push_back(ConstantExpr::getMul(C1, C2));
1313 return ConstantVector::get(Res);
1314 case Instruction::FMul:
1315 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1316 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1317 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1318 Res.push_back(ConstantExpr::getFMul(C1, C2));
1320 return ConstantVector::get(Res);
1321 case Instruction::UDiv:
1322 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1323 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1324 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1325 Res.push_back(ConstantExpr::getUDiv(C1, C2));
1327 return ConstantVector::get(Res);
1328 case Instruction::SDiv:
1329 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1330 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1331 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1332 Res.push_back(ConstantExpr::getSDiv(C1, C2));
1334 return ConstantVector::get(Res);
1335 case Instruction::FDiv:
1336 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1337 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1338 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1339 Res.push_back(ConstantExpr::getFDiv(C1, C2));
1341 return ConstantVector::get(Res);
1342 case Instruction::URem:
1343 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1344 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1345 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1346 Res.push_back(ConstantExpr::getURem(C1, C2));
1348 return ConstantVector::get(Res);
1349 case Instruction::SRem:
1350 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1351 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1352 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1353 Res.push_back(ConstantExpr::getSRem(C1, C2));
1355 return ConstantVector::get(Res);
1356 case Instruction::FRem:
1357 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1358 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1359 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1360 Res.push_back(ConstantExpr::getFRem(C1, C2));
1362 return ConstantVector::get(Res);
1363 case Instruction::And:
1364 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1365 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1366 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1367 Res.push_back(ConstantExpr::getAnd(C1, C2));
1369 return ConstantVector::get(Res);
1370 case Instruction::Or:
1371 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1372 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1373 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1374 Res.push_back(ConstantExpr::getOr(C1, C2));
1376 return ConstantVector::get(Res);
1377 case Instruction::Xor:
1378 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1379 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1380 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1381 Res.push_back(ConstantExpr::getXor(C1, C2));
1383 return ConstantVector::get(Res);
1384 case Instruction::LShr:
1385 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1386 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1387 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1388 Res.push_back(ConstantExpr::getLShr(C1, C2));
1390 return ConstantVector::get(Res);
1391 case Instruction::AShr:
1392 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1393 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1394 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1395 Res.push_back(ConstantExpr::getAShr(C1, C2));
1397 return ConstantVector::get(Res);
1398 case Instruction::Shl:
1399 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
1400 C1 = CP1 ? CP1->getOperand(i) : Constant::getNullValue(EltTy);
1401 C2 = CP2 ? CP2->getOperand(i) : Constant::getNullValue(EltTy);
1402 Res.push_back(ConstantExpr::getShl(C1, C2));
1404 return ConstantVector::get(Res);
1409 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
1410 // There are many possible foldings we could do here. We should probably
1411 // at least fold add of a pointer with an integer into the appropriate
1412 // getelementptr. This will improve alias analysis a bit.
1414 // Given ((a + b) + c), if (b + c) folds to something interesting, return
1416 if (Instruction::isAssociative(Opcode) && CE1->getOpcode() == Opcode) {
1417 Constant *T = ConstantExpr::get(Opcode, CE1->getOperand(1), C2);
1418 if (!isa<ConstantExpr>(T) || cast<ConstantExpr>(T)->getOpcode() != Opcode)
1419 return ConstantExpr::get(Opcode, CE1->getOperand(0), T);
1421 } else if (isa<ConstantExpr>(C2)) {
1422 // If C2 is a constant expr and C1 isn't, flop them around and fold the
1423 // other way if possible.
1424 if (Instruction::isCommutative(Opcode))
1425 return ConstantFoldBinaryInstruction(Opcode, C2, C1);
1428 // i1 can be simplified in many cases.
1429 if (C1->getType()->isIntegerTy(1)) {
1431 case Instruction::Add:
1432 case Instruction::Sub:
1433 return ConstantExpr::getXor(C1, C2);
1434 case Instruction::Mul:
1435 return ConstantExpr::getAnd(C1, C2);
1436 case Instruction::Shl:
1437 case Instruction::LShr:
1438 case Instruction::AShr:
1439 // We can assume that C2 == 0. If it were one the result would be
1440 // undefined because the shift value is as large as the bitwidth.
1442 case Instruction::SDiv:
1443 case Instruction::UDiv:
1444 // We can assume that C2 == 1. If it were zero the result would be
1445 // undefined through division by zero.
1447 case Instruction::URem:
1448 case Instruction::SRem:
1449 // We can assume that C2 == 1. If it were zero the result would be
1450 // undefined through division by zero.
1451 return ConstantInt::getFalse(C1->getContext());
1457 // We don't know how to fold this.
1461 /// isZeroSizedType - This type is zero sized if its an array or structure of
1462 /// zero sized types. The only leaf zero sized type is an empty structure.
1463 static bool isMaybeZeroSizedType(Type *Ty) {
1464 if (StructType *STy = dyn_cast<StructType>(Ty)) {
1465 if (STy->isOpaque()) return true; // Can't say.
1467 // If all of elements have zero size, this does too.
1468 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
1469 if (!isMaybeZeroSizedType(STy->getElementType(i))) return false;
1472 } else if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
1473 return isMaybeZeroSizedType(ATy->getElementType());
1478 /// IdxCompare - Compare the two constants as though they were getelementptr
1479 /// indices. This allows coersion of the types to be the same thing.
1481 /// If the two constants are the "same" (after coersion), return 0. If the
1482 /// first is less than the second, return -1, if the second is less than the
1483 /// first, return 1. If the constants are not integral, return -2.
1485 static int IdxCompare(Constant *C1, Constant *C2, Type *ElTy) {
1486 if (C1 == C2) return 0;
1488 // Ok, we found a different index. If they are not ConstantInt, we can't do
1489 // anything with them.
1490 if (!isa<ConstantInt>(C1) || !isa<ConstantInt>(C2))
1491 return -2; // don't know!
1493 // Ok, we have two differing integer indices. Sign extend them to be the same
1494 // type. Long is always big enough, so we use it.
1495 if (!C1->getType()->isIntegerTy(64))
1496 C1 = ConstantExpr::getSExt(C1, Type::getInt64Ty(C1->getContext()));
1498 if (!C2->getType()->isIntegerTy(64))
1499 C2 = ConstantExpr::getSExt(C2, Type::getInt64Ty(C1->getContext()));
1501 if (C1 == C2) return 0; // They are equal
1503 // If the type being indexed over is really just a zero sized type, there is
1504 // no pointer difference being made here.
1505 if (isMaybeZeroSizedType(ElTy))
1506 return -2; // dunno.
1508 // If they are really different, now that they are the same type, then we
1509 // found a difference!
1510 if (cast<ConstantInt>(C1)->getSExtValue() <
1511 cast<ConstantInt>(C2)->getSExtValue())
1517 /// evaluateFCmpRelation - This function determines if there is anything we can
1518 /// decide about the two constants provided. This doesn't need to handle simple
1519 /// things like ConstantFP comparisons, but should instead handle ConstantExprs.
1520 /// If we can determine that the two constants have a particular relation to
1521 /// each other, we should return the corresponding FCmpInst predicate,
1522 /// otherwise return FCmpInst::BAD_FCMP_PREDICATE. This is used below in
1523 /// ConstantFoldCompareInstruction.
1525 /// To simplify this code we canonicalize the relation so that the first
1526 /// operand is always the most "complex" of the two. We consider ConstantFP
1527 /// to be the simplest, and ConstantExprs to be the most complex.
1528 static FCmpInst::Predicate evaluateFCmpRelation(Constant *V1, Constant *V2) {
1529 assert(V1->getType() == V2->getType() &&
1530 "Cannot compare values of different types!");
1532 // No compile-time operations on this type yet.
1533 if (V1->getType()->isPPC_FP128Ty())
1534 return FCmpInst::BAD_FCMP_PREDICATE;
1536 // Handle degenerate case quickly
1537 if (V1 == V2) return FCmpInst::FCMP_OEQ;
1539 if (!isa<ConstantExpr>(V1)) {
1540 if (!isa<ConstantExpr>(V2)) {
1541 // We distilled thisUse the standard constant folder for a few cases
1543 R = dyn_cast<ConstantInt>(
1544 ConstantExpr::getFCmp(FCmpInst::FCMP_OEQ, V1, V2));
1545 if (R && !R->isZero())
1546 return FCmpInst::FCMP_OEQ;
1547 R = dyn_cast<ConstantInt>(
1548 ConstantExpr::getFCmp(FCmpInst::FCMP_OLT, V1, V2));
1549 if (R && !R->isZero())
1550 return FCmpInst::FCMP_OLT;
1551 R = dyn_cast<ConstantInt>(
1552 ConstantExpr::getFCmp(FCmpInst::FCMP_OGT, V1, V2));
1553 if (R && !R->isZero())
1554 return FCmpInst::FCMP_OGT;
1556 // Nothing more we can do
1557 return FCmpInst::BAD_FCMP_PREDICATE;
1560 // If the first operand is simple and second is ConstantExpr, swap operands.
1561 FCmpInst::Predicate SwappedRelation = evaluateFCmpRelation(V2, V1);
1562 if (SwappedRelation != FCmpInst::BAD_FCMP_PREDICATE)
1563 return FCmpInst::getSwappedPredicate(SwappedRelation);
1565 // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1566 // constantexpr or a simple constant.
1567 ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1568 switch (CE1->getOpcode()) {
1569 case Instruction::FPTrunc:
1570 case Instruction::FPExt:
1571 case Instruction::UIToFP:
1572 case Instruction::SIToFP:
1573 // We might be able to do something with these but we don't right now.
1579 // There are MANY other foldings that we could perform here. They will
1580 // probably be added on demand, as they seem needed.
1581 return FCmpInst::BAD_FCMP_PREDICATE;
1584 /// evaluateICmpRelation - This function determines if there is anything we can
1585 /// decide about the two constants provided. This doesn't need to handle simple
1586 /// things like integer comparisons, but should instead handle ConstantExprs
1587 /// and GlobalValues. If we can determine that the two constants have a
1588 /// particular relation to each other, we should return the corresponding ICmp
1589 /// predicate, otherwise return ICmpInst::BAD_ICMP_PREDICATE.
1591 /// To simplify this code we canonicalize the relation so that the first
1592 /// operand is always the most "complex" of the two. We consider simple
1593 /// constants (like ConstantInt) to be the simplest, followed by
1594 /// GlobalValues, followed by ConstantExpr's (the most complex).
1596 static ICmpInst::Predicate evaluateICmpRelation(Constant *V1, Constant *V2,
1598 assert(V1->getType() == V2->getType() &&
1599 "Cannot compare different types of values!");
1600 if (V1 == V2) return ICmpInst::ICMP_EQ;
1602 if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1) &&
1603 !isa<BlockAddress>(V1)) {
1604 if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2) &&
1605 !isa<BlockAddress>(V2)) {
1606 // We distilled this down to a simple case, use the standard constant
1609 ICmpInst::Predicate pred = ICmpInst::ICMP_EQ;
1610 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1611 if (R && !R->isZero())
1613 pred = isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1614 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1615 if (R && !R->isZero())
1617 pred = isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1618 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
1619 if (R && !R->isZero())
1622 // If we couldn't figure it out, bail.
1623 return ICmpInst::BAD_ICMP_PREDICATE;
1626 // If the first operand is simple, swap operands.
1627 ICmpInst::Predicate SwappedRelation =
1628 evaluateICmpRelation(V2, V1, isSigned);
1629 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1630 return ICmpInst::getSwappedPredicate(SwappedRelation);
1632 } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1)) {
1633 if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1634 ICmpInst::Predicate SwappedRelation =
1635 evaluateICmpRelation(V2, V1, isSigned);
1636 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1637 return ICmpInst::getSwappedPredicate(SwappedRelation);
1638 return ICmpInst::BAD_ICMP_PREDICATE;
1641 // Now we know that the RHS is a GlobalValue, BlockAddress or simple
1642 // constant (which, since the types must match, means that it's a
1643 // ConstantPointerNull).
1644 if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
1645 // Don't try to decide equality of aliases.
1646 if (!isa<GlobalAlias>(GV) && !isa<GlobalAlias>(GV2))
1647 if (!GV->hasExternalWeakLinkage() || !GV2->hasExternalWeakLinkage())
1648 return ICmpInst::ICMP_NE;
1649 } else if (isa<BlockAddress>(V2)) {
1650 return ICmpInst::ICMP_NE; // Globals never equal labels.
1652 assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!");
1653 // GlobalVals can never be null unless they have external weak linkage.
1654 // We don't try to evaluate aliases here.
1655 if (!GV->hasExternalWeakLinkage() && !isa<GlobalAlias>(GV))
1656 return ICmpInst::ICMP_NE;
1658 } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(V1)) {
1659 if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1660 ICmpInst::Predicate SwappedRelation =
1661 evaluateICmpRelation(V2, V1, isSigned);
1662 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1663 return ICmpInst::getSwappedPredicate(SwappedRelation);
1664 return ICmpInst::BAD_ICMP_PREDICATE;
1667 // Now we know that the RHS is a GlobalValue, BlockAddress or simple
1668 // constant (which, since the types must match, means that it is a
1669 // ConstantPointerNull).
1670 if (const BlockAddress *BA2 = dyn_cast<BlockAddress>(V2)) {
1671 // Block address in another function can't equal this one, but block
1672 // addresses in the current function might be the same if blocks are
1674 if (BA2->getFunction() != BA->getFunction())
1675 return ICmpInst::ICMP_NE;
1677 // Block addresses aren't null, don't equal the address of globals.
1678 assert((isa<ConstantPointerNull>(V2) || isa<GlobalValue>(V2)) &&
1679 "Canonicalization guarantee!");
1680 return ICmpInst::ICMP_NE;
1683 // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1684 // constantexpr, a global, block address, or a simple constant.
1685 ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1686 Constant *CE1Op0 = CE1->getOperand(0);
1688 switch (CE1->getOpcode()) {
1689 case Instruction::Trunc:
1690 case Instruction::FPTrunc:
1691 case Instruction::FPExt:
1692 case Instruction::FPToUI:
1693 case Instruction::FPToSI:
1694 break; // We can't evaluate floating point casts or truncations.
1696 case Instruction::UIToFP:
1697 case Instruction::SIToFP:
1698 case Instruction::BitCast:
1699 case Instruction::ZExt:
1700 case Instruction::SExt:
1701 // If the cast is not actually changing bits, and the second operand is a
1702 // null pointer, do the comparison with the pre-casted value.
1703 if (V2->isNullValue() &&
1704 (CE1->getType()->isPointerTy() || CE1->getType()->isIntegerTy())) {
1705 if (CE1->getOpcode() == Instruction::ZExt) isSigned = false;
1706 if (CE1->getOpcode() == Instruction::SExt) isSigned = true;
1707 return evaluateICmpRelation(CE1Op0,
1708 Constant::getNullValue(CE1Op0->getType()),
1713 case Instruction::GetElementPtr:
1714 // Ok, since this is a getelementptr, we know that the constant has a
1715 // pointer type. Check the various cases.
1716 if (isa<ConstantPointerNull>(V2)) {
1717 // If we are comparing a GEP to a null pointer, check to see if the base
1718 // of the GEP equals the null pointer.
1719 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1720 if (GV->hasExternalWeakLinkage())
1721 // Weak linkage GVals could be zero or not. We're comparing that
1722 // to null pointer so its greater-or-equal
1723 return isSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE;
1725 // If its not weak linkage, the GVal must have a non-zero address
1726 // so the result is greater-than
1727 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1728 } else if (isa<ConstantPointerNull>(CE1Op0)) {
1729 // If we are indexing from a null pointer, check to see if we have any
1730 // non-zero indices.
1731 for (unsigned i = 1, e = CE1->getNumOperands(); i != e; ++i)
1732 if (!CE1->getOperand(i)->isNullValue())
1733 // Offsetting from null, must not be equal.
1734 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1735 // Only zero indexes from null, must still be zero.
1736 return ICmpInst::ICMP_EQ;
1738 // Otherwise, we can't really say if the first operand is null or not.
1739 } else if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
1740 if (isa<ConstantPointerNull>(CE1Op0)) {
1741 if (GV2->hasExternalWeakLinkage())
1742 // Weak linkage GVals could be zero or not. We're comparing it to
1743 // a null pointer, so its less-or-equal
1744 return isSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE;
1746 // If its not weak linkage, the GVal must have a non-zero address
1747 // so the result is less-than
1748 return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1749 } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1751 // If this is a getelementptr of the same global, then it must be
1752 // different. Because the types must match, the getelementptr could
1753 // only have at most one index, and because we fold getelementptr's
1754 // with a single zero index, it must be nonzero.
1755 assert(CE1->getNumOperands() == 2 &&
1756 !CE1->getOperand(1)->isNullValue() &&
1757 "Surprising getelementptr!");
1758 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1760 // If they are different globals, we don't know what the value is,
1761 // but they can't be equal.
1762 return ICmpInst::ICMP_NE;
1766 ConstantExpr *CE2 = cast<ConstantExpr>(V2);
1767 Constant *CE2Op0 = CE2->getOperand(0);
1769 // There are MANY other foldings that we could perform here. They will
1770 // probably be added on demand, as they seem needed.
1771 switch (CE2->getOpcode()) {
1773 case Instruction::GetElementPtr:
1774 // By far the most common case to handle is when the base pointers are
1775 // obviously to the same or different globals.
1776 if (isa<GlobalValue>(CE1Op0) && isa<GlobalValue>(CE2Op0)) {
1777 if (CE1Op0 != CE2Op0) // Don't know relative ordering, but not equal
1778 return ICmpInst::ICMP_NE;
1779 // Ok, we know that both getelementptr instructions are based on the
1780 // same global. From this, we can precisely determine the relative
1781 // ordering of the resultant pointers.
1784 // The logic below assumes that the result of the comparison
1785 // can be determined by finding the first index that differs.
1786 // This doesn't work if there is over-indexing in any
1787 // subsequent indices, so check for that case first.
1788 if (!CE1->isGEPWithNoNotionalOverIndexing() ||
1789 !CE2->isGEPWithNoNotionalOverIndexing())
1790 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1792 // Compare all of the operands the GEP's have in common.
1793 gep_type_iterator GTI = gep_type_begin(CE1);
1794 for (;i != CE1->getNumOperands() && i != CE2->getNumOperands();
1796 switch (IdxCompare(CE1->getOperand(i),
1797 CE2->getOperand(i), GTI.getIndexedType())) {
1798 case -1: return isSigned ? ICmpInst::ICMP_SLT:ICmpInst::ICMP_ULT;
1799 case 1: return isSigned ? ICmpInst::ICMP_SGT:ICmpInst::ICMP_UGT;
1800 case -2: return ICmpInst::BAD_ICMP_PREDICATE;
1803 // Ok, we ran out of things they have in common. If any leftovers
1804 // are non-zero then we have a difference, otherwise we are equal.
1805 for (; i < CE1->getNumOperands(); ++i)
1806 if (!CE1->getOperand(i)->isNullValue()) {
1807 if (isa<ConstantInt>(CE1->getOperand(i)))
1808 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1810 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1813 for (; i < CE2->getNumOperands(); ++i)
1814 if (!CE2->getOperand(i)->isNullValue()) {
1815 if (isa<ConstantInt>(CE2->getOperand(i)))
1816 return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1818 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1820 return ICmpInst::ICMP_EQ;
1829 return ICmpInst::BAD_ICMP_PREDICATE;
1832 Constant *llvm::ConstantFoldCompareInstruction(unsigned short pred,
1833 Constant *C1, Constant *C2) {
1835 if (VectorType *VT = dyn_cast<VectorType>(C1->getType()))
1836 ResultTy = VectorType::get(Type::getInt1Ty(C1->getContext()),
1837 VT->getNumElements());
1839 ResultTy = Type::getInt1Ty(C1->getContext());
1841 // Fold FCMP_FALSE/FCMP_TRUE unconditionally.
1842 if (pred == FCmpInst::FCMP_FALSE)
1843 return Constant::getNullValue(ResultTy);
1845 if (pred == FCmpInst::FCMP_TRUE)
1846 return Constant::getAllOnesValue(ResultTy);
1848 // Handle some degenerate cases first
1849 if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
1850 // For EQ and NE, we can always pick a value for the undef to make the
1851 // predicate pass or fail, so we can return undef.
1852 // Also, if both operands are undef, we can return undef.
1853 if (ICmpInst::isEquality(ICmpInst::Predicate(pred)) ||
1854 (isa<UndefValue>(C1) && isa<UndefValue>(C2)))
1855 return UndefValue::get(ResultTy);
1856 // Otherwise, pick the same value as the non-undef operand, and fold
1857 // it to true or false.
1858 return ConstantInt::get(ResultTy, CmpInst::isTrueWhenEqual(pred));
1861 // No compile-time operations on this type yet.
1862 if (C1->getType()->isPPC_FP128Ty())
1865 // icmp eq/ne(null,GV) -> false/true
1866 if (C1->isNullValue()) {
1867 if (const GlobalValue *GV = dyn_cast<GlobalValue>(C2))
1868 // Don't try to evaluate aliases. External weak GV can be null.
1869 if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
1870 if (pred == ICmpInst::ICMP_EQ)
1871 return ConstantInt::getFalse(C1->getContext());
1872 else if (pred == ICmpInst::ICMP_NE)
1873 return ConstantInt::getTrue(C1->getContext());
1875 // icmp eq/ne(GV,null) -> false/true
1876 } else if (C2->isNullValue()) {
1877 if (const GlobalValue *GV = dyn_cast<GlobalValue>(C1))
1878 // Don't try to evaluate aliases. External weak GV can be null.
1879 if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
1880 if (pred == ICmpInst::ICMP_EQ)
1881 return ConstantInt::getFalse(C1->getContext());
1882 else if (pred == ICmpInst::ICMP_NE)
1883 return ConstantInt::getTrue(C1->getContext());
1887 // If the comparison is a comparison between two i1's, simplify it.
1888 if (C1->getType()->isIntegerTy(1)) {
1890 case ICmpInst::ICMP_EQ:
1891 if (isa<ConstantInt>(C2))
1892 return ConstantExpr::getXor(C1, ConstantExpr::getNot(C2));
1893 return ConstantExpr::getXor(ConstantExpr::getNot(C1), C2);
1894 case ICmpInst::ICMP_NE:
1895 return ConstantExpr::getXor(C1, C2);
1901 if (isa<ConstantInt>(C1) && isa<ConstantInt>(C2)) {
1902 APInt V1 = cast<ConstantInt>(C1)->getValue();
1903 APInt V2 = cast<ConstantInt>(C2)->getValue();
1905 default: llvm_unreachable("Invalid ICmp Predicate"); return 0;
1906 case ICmpInst::ICMP_EQ: return ConstantInt::get(ResultTy, V1 == V2);
1907 case ICmpInst::ICMP_NE: return ConstantInt::get(ResultTy, V1 != V2);
1908 case ICmpInst::ICMP_SLT: return ConstantInt::get(ResultTy, V1.slt(V2));
1909 case ICmpInst::ICMP_SGT: return ConstantInt::get(ResultTy, V1.sgt(V2));
1910 case ICmpInst::ICMP_SLE: return ConstantInt::get(ResultTy, V1.sle(V2));
1911 case ICmpInst::ICMP_SGE: return ConstantInt::get(ResultTy, V1.sge(V2));
1912 case ICmpInst::ICMP_ULT: return ConstantInt::get(ResultTy, V1.ult(V2));
1913 case ICmpInst::ICMP_UGT: return ConstantInt::get(ResultTy, V1.ugt(V2));
1914 case ICmpInst::ICMP_ULE: return ConstantInt::get(ResultTy, V1.ule(V2));
1915 case ICmpInst::ICMP_UGE: return ConstantInt::get(ResultTy, V1.uge(V2));
1917 } else if (isa<ConstantFP>(C1) && isa<ConstantFP>(C2)) {
1918 APFloat C1V = cast<ConstantFP>(C1)->getValueAPF();
1919 APFloat C2V = cast<ConstantFP>(C2)->getValueAPF();
1920 APFloat::cmpResult R = C1V.compare(C2V);
1922 default: llvm_unreachable("Invalid FCmp Predicate"); return 0;
1923 case FCmpInst::FCMP_FALSE: return Constant::getNullValue(ResultTy);
1924 case FCmpInst::FCMP_TRUE: return Constant::getAllOnesValue(ResultTy);
1925 case FCmpInst::FCMP_UNO:
1926 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered);
1927 case FCmpInst::FCMP_ORD:
1928 return ConstantInt::get(ResultTy, R!=APFloat::cmpUnordered);
1929 case FCmpInst::FCMP_UEQ:
1930 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1931 R==APFloat::cmpEqual);
1932 case FCmpInst::FCMP_OEQ:
1933 return ConstantInt::get(ResultTy, R==APFloat::cmpEqual);
1934 case FCmpInst::FCMP_UNE:
1935 return ConstantInt::get(ResultTy, R!=APFloat::cmpEqual);
1936 case FCmpInst::FCMP_ONE:
1937 return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
1938 R==APFloat::cmpGreaterThan);
1939 case FCmpInst::FCMP_ULT:
1940 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1941 R==APFloat::cmpLessThan);
1942 case FCmpInst::FCMP_OLT:
1943 return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan);
1944 case FCmpInst::FCMP_UGT:
1945 return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
1946 R==APFloat::cmpGreaterThan);
1947 case FCmpInst::FCMP_OGT:
1948 return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan);
1949 case FCmpInst::FCMP_ULE:
1950 return ConstantInt::get(ResultTy, R!=APFloat::cmpGreaterThan);
1951 case FCmpInst::FCMP_OLE:
1952 return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
1953 R==APFloat::cmpEqual);
1954 case FCmpInst::FCMP_UGE:
1955 return ConstantInt::get(ResultTy, R!=APFloat::cmpLessThan);
1956 case FCmpInst::FCMP_OGE:
1957 return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan ||
1958 R==APFloat::cmpEqual);
1960 } else if (C1->getType()->isVectorTy()) {
1961 SmallVector<Constant*, 16> C1Elts, C2Elts;
1962 C1->getVectorElements(C1Elts);
1963 C2->getVectorElements(C2Elts);
1964 if (C1Elts.empty() || C2Elts.empty())
1967 // If we can constant fold the comparison of each element, constant fold
1968 // the whole vector comparison.
1969 SmallVector<Constant*, 4> ResElts;
1970 // Compare the elements, producing an i1 result or constant expr.
1971 for (unsigned i = 0, e = C1Elts.size(); i != e; ++i)
1972 ResElts.push_back(ConstantExpr::getCompare(pred, C1Elts[i], C2Elts[i]));
1974 return ConstantVector::get(ResElts);
1977 if (C1->getType()->isFloatingPointTy()) {
1978 int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
1979 switch (evaluateFCmpRelation(C1, C2)) {
1980 default: llvm_unreachable("Unknown relation!");
1981 case FCmpInst::FCMP_UNO:
1982 case FCmpInst::FCMP_ORD:
1983 case FCmpInst::FCMP_UEQ:
1984 case FCmpInst::FCMP_UNE:
1985 case FCmpInst::FCMP_ULT:
1986 case FCmpInst::FCMP_UGT:
1987 case FCmpInst::FCMP_ULE:
1988 case FCmpInst::FCMP_UGE:
1989 case FCmpInst::FCMP_TRUE:
1990 case FCmpInst::FCMP_FALSE:
1991 case FCmpInst::BAD_FCMP_PREDICATE:
1992 break; // Couldn't determine anything about these constants.
1993 case FCmpInst::FCMP_OEQ: // We know that C1 == C2
1994 Result = (pred == FCmpInst::FCMP_UEQ || pred == FCmpInst::FCMP_OEQ ||
1995 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE ||
1996 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
1998 case FCmpInst::FCMP_OLT: // We know that C1 < C2
1999 Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
2000 pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT ||
2001 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE);
2003 case FCmpInst::FCMP_OGT: // We know that C1 > C2
2004 Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
2005 pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT ||
2006 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
2008 case FCmpInst::FCMP_OLE: // We know that C1 <= C2
2009 // We can only partially decide this relation.
2010 if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
2012 else if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
2015 case FCmpInst::FCMP_OGE: // We known that C1 >= C2
2016 // We can only partially decide this relation.
2017 if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
2019 else if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
2022 case FCmpInst::FCMP_ONE: // We know that C1 != C2
2023 // We can only partially decide this relation.
2024 if (pred == FCmpInst::FCMP_OEQ || pred == FCmpInst::FCMP_UEQ)
2026 else if (pred == FCmpInst::FCMP_ONE || pred == FCmpInst::FCMP_UNE)
2031 // If we evaluated the result, return it now.
2033 return ConstantInt::get(ResultTy, Result);
2036 // Evaluate the relation between the two constants, per the predicate.
2037 int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
2038 switch (evaluateICmpRelation(C1, C2, CmpInst::isSigned(pred))) {
2039 default: llvm_unreachable("Unknown relational!");
2040 case ICmpInst::BAD_ICMP_PREDICATE:
2041 break; // Couldn't determine anything about these constants.
2042 case ICmpInst::ICMP_EQ: // We know the constants are equal!
2043 // If we know the constants are equal, we can decide the result of this
2044 // computation precisely.
2045 Result = ICmpInst::isTrueWhenEqual((ICmpInst::Predicate)pred);
2047 case ICmpInst::ICMP_ULT:
2049 case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_ULE:
2051 case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_UGE:
2055 case ICmpInst::ICMP_SLT:
2057 case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SLE:
2059 case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SGE:
2063 case ICmpInst::ICMP_UGT:
2065 case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_UGE:
2067 case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_ULE:
2071 case ICmpInst::ICMP_SGT:
2073 case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SGE:
2075 case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SLE:
2079 case ICmpInst::ICMP_ULE:
2080 if (pred == ICmpInst::ICMP_UGT) Result = 0;
2081 if (pred == ICmpInst::ICMP_ULT || pred == ICmpInst::ICMP_ULE) Result = 1;
2083 case ICmpInst::ICMP_SLE:
2084 if (pred == ICmpInst::ICMP_SGT) Result = 0;
2085 if (pred == ICmpInst::ICMP_SLT || pred == ICmpInst::ICMP_SLE) Result = 1;
2087 case ICmpInst::ICMP_UGE:
2088 if (pred == ICmpInst::ICMP_ULT) Result = 0;
2089 if (pred == ICmpInst::ICMP_UGT || pred == ICmpInst::ICMP_UGE) Result = 1;
2091 case ICmpInst::ICMP_SGE:
2092 if (pred == ICmpInst::ICMP_SLT) Result = 0;
2093 if (pred == ICmpInst::ICMP_SGT || pred == ICmpInst::ICMP_SGE) Result = 1;
2095 case ICmpInst::ICMP_NE:
2096 if (pred == ICmpInst::ICMP_EQ) Result = 0;
2097 if (pred == ICmpInst::ICMP_NE) Result = 1;
2101 // If we evaluated the result, return it now.
2103 return ConstantInt::get(ResultTy, Result);
2105 // If the right hand side is a bitcast, try using its inverse to simplify
2106 // it by moving it to the left hand side. We can't do this if it would turn
2107 // a vector compare into a scalar compare or visa versa.
2108 if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(C2)) {
2109 Constant *CE2Op0 = CE2->getOperand(0);
2110 if (CE2->getOpcode() == Instruction::BitCast &&
2111 CE2->getType()->isVectorTy() == CE2Op0->getType()->isVectorTy()) {
2112 Constant *Inverse = ConstantExpr::getBitCast(C1, CE2Op0->getType());
2113 return ConstantExpr::getICmp(pred, Inverse, CE2Op0);
2117 // If the left hand side is an extension, try eliminating it.
2118 if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
2119 if ((CE1->getOpcode() == Instruction::SExt && ICmpInst::isSigned(pred)) ||
2120 (CE1->getOpcode() == Instruction::ZExt && !ICmpInst::isSigned(pred))){
2121 Constant *CE1Op0 = CE1->getOperand(0);
2122 Constant *CE1Inverse = ConstantExpr::getTrunc(CE1, CE1Op0->getType());
2123 if (CE1Inverse == CE1Op0) {
2124 // Check whether we can safely truncate the right hand side.
2125 Constant *C2Inverse = ConstantExpr::getTrunc(C2, CE1Op0->getType());
2126 if (ConstantExpr::getZExt(C2Inverse, C2->getType()) == C2) {
2127 return ConstantExpr::getICmp(pred, CE1Inverse, C2Inverse);
2133 if ((!isa<ConstantExpr>(C1) && isa<ConstantExpr>(C2)) ||
2134 (C1->isNullValue() && !C2->isNullValue())) {
2135 // If C2 is a constant expr and C1 isn't, flip them around and fold the
2136 // other way if possible.
2137 // Also, if C1 is null and C2 isn't, flip them around.
2138 pred = ICmpInst::getSwappedPredicate((ICmpInst::Predicate)pred);
2139 return ConstantExpr::getICmp(pred, C2, C1);
2145 /// isInBoundsIndices - Test whether the given sequence of *normalized* indices
2147 template<typename IndexTy>
2148 static bool isInBoundsIndices(ArrayRef<IndexTy> Idxs) {
2149 // No indices means nothing that could be out of bounds.
2150 if (Idxs.empty()) return true;
2152 // If the first index is zero, it's in bounds.
2153 if (cast<Constant>(Idxs[0])->isNullValue()) return true;
2155 // If the first index is one and all the rest are zero, it's in bounds,
2156 // by the one-past-the-end rule.
2157 if (!cast<ConstantInt>(Idxs[0])->isOne())
2159 for (unsigned i = 1, e = Idxs.size(); i != e; ++i)
2160 if (!cast<Constant>(Idxs[i])->isNullValue())
2165 template<typename IndexTy>
2166 static Constant *ConstantFoldGetElementPtrImpl(Constant *C,
2168 ArrayRef<IndexTy> Idxs) {
2169 if (Idxs.empty()) return C;
2170 Constant *Idx0 = cast<Constant>(Idxs[0]);
2171 if ((Idxs.size() == 1 && Idx0->isNullValue()))
2174 if (isa<UndefValue>(C)) {
2175 PointerType *Ptr = cast<PointerType>(C->getType());
2176 Type *Ty = GetElementPtrInst::getIndexedType(Ptr, Idxs);
2177 assert(Ty != 0 && "Invalid indices for GEP!");
2178 return UndefValue::get(PointerType::get(Ty, Ptr->getAddressSpace()));
2181 if (C->isNullValue()) {
2183 for (unsigned i = 0, e = Idxs.size(); i != e; ++i)
2184 if (!cast<Constant>(Idxs[i])->isNullValue()) {
2189 PointerType *Ptr = cast<PointerType>(C->getType());
2190 Type *Ty = GetElementPtrInst::getIndexedType(Ptr, Idxs);
2191 assert(Ty != 0 && "Invalid indices for GEP!");
2192 return ConstantPointerNull::get(PointerType::get(Ty,
2193 Ptr->getAddressSpace()));
2197 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2198 // Combine Indices - If the source pointer to this getelementptr instruction
2199 // is a getelementptr instruction, combine the indices of the two
2200 // getelementptr instructions into a single instruction.
2202 if (CE->getOpcode() == Instruction::GetElementPtr) {
2204 for (gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
2208 if ((LastTy && LastTy->isArrayTy()) || Idx0->isNullValue()) {
2209 SmallVector<Value*, 16> NewIndices;
2210 NewIndices.reserve(Idxs.size() + CE->getNumOperands());
2211 for (unsigned i = 1, e = CE->getNumOperands()-1; i != e; ++i)
2212 NewIndices.push_back(CE->getOperand(i));
2214 // Add the last index of the source with the first index of the new GEP.
2215 // Make sure to handle the case when they are actually different types.
2216 Constant *Combined = CE->getOperand(CE->getNumOperands()-1);
2217 // Otherwise it must be an array.
2218 if (!Idx0->isNullValue()) {
2219 Type *IdxTy = Combined->getType();
2220 if (IdxTy != Idx0->getType()) {
2221 Type *Int64Ty = Type::getInt64Ty(IdxTy->getContext());
2222 Constant *C1 = ConstantExpr::getSExtOrBitCast(Idx0, Int64Ty);
2223 Constant *C2 = ConstantExpr::getSExtOrBitCast(Combined, Int64Ty);
2224 Combined = ConstantExpr::get(Instruction::Add, C1, C2);
2227 ConstantExpr::get(Instruction::Add, Idx0, Combined);
2231 NewIndices.push_back(Combined);
2232 NewIndices.append(Idxs.begin() + 1, Idxs.end());
2234 ConstantExpr::getGetElementPtr(CE->getOperand(0), NewIndices,
2236 cast<GEPOperator>(CE)->isInBounds());
2240 // Implement folding of:
2241 // i32* getelementptr ([2 x i32]* bitcast ([3 x i32]* %X to [2 x i32]*),
2243 // To: i32* getelementptr ([3 x i32]* %X, i64 0, i64 0)
2245 if (CE->isCast() && Idxs.size() > 1 && Idx0->isNullValue()) {
2246 if (PointerType *SPT =
2247 dyn_cast<PointerType>(CE->getOperand(0)->getType()))
2248 if (ArrayType *SAT = dyn_cast<ArrayType>(SPT->getElementType()))
2249 if (ArrayType *CAT =
2250 dyn_cast<ArrayType>(cast<PointerType>(C->getType())->getElementType()))
2251 if (CAT->getElementType() == SAT->getElementType())
2253 ConstantExpr::getGetElementPtr((Constant*)CE->getOperand(0),
2258 // Check to see if any array indices are not within the corresponding
2259 // notional array bounds. If so, try to determine if they can be factored
2260 // out into preceding dimensions.
2261 bool Unknown = false;
2262 SmallVector<Constant *, 8> NewIdxs;
2263 Type *Ty = C->getType();
2265 for (unsigned i = 0, e = Idxs.size(); i != e;
2266 Prev = Ty, Ty = cast<CompositeType>(Ty)->getTypeAtIndex(Idxs[i]), ++i) {
2267 if (ConstantInt *CI = dyn_cast<ConstantInt>(Idxs[i])) {
2268 if (ArrayType *ATy = dyn_cast<ArrayType>(Ty))
2269 if (ATy->getNumElements() <= INT64_MAX &&
2270 ATy->getNumElements() != 0 &&
2271 CI->getSExtValue() >= (int64_t)ATy->getNumElements()) {
2272 if (isa<SequentialType>(Prev)) {
2273 // It's out of range, but we can factor it into the prior
2275 NewIdxs.resize(Idxs.size());
2276 ConstantInt *Factor = ConstantInt::get(CI->getType(),
2277 ATy->getNumElements());
2278 NewIdxs[i] = ConstantExpr::getSRem(CI, Factor);
2280 Constant *PrevIdx = cast<Constant>(Idxs[i-1]);
2281 Constant *Div = ConstantExpr::getSDiv(CI, Factor);
2283 // Before adding, extend both operands to i64 to avoid
2284 // overflow trouble.
2285 if (!PrevIdx->getType()->isIntegerTy(64))
2286 PrevIdx = ConstantExpr::getSExt(PrevIdx,
2287 Type::getInt64Ty(Div->getContext()));
2288 if (!Div->getType()->isIntegerTy(64))
2289 Div = ConstantExpr::getSExt(Div,
2290 Type::getInt64Ty(Div->getContext()));
2292 NewIdxs[i-1] = ConstantExpr::getAdd(PrevIdx, Div);
2294 // It's out of range, but the prior dimension is a struct
2295 // so we can't do anything about it.
2300 // We don't know if it's in range or not.
2305 // If we did any factoring, start over with the adjusted indices.
2306 if (!NewIdxs.empty()) {
2307 for (unsigned i = 0, e = Idxs.size(); i != e; ++i)
2308 if (!NewIdxs[i]) NewIdxs[i] = cast<Constant>(Idxs[i]);
2309 return ConstantExpr::getGetElementPtr(C, NewIdxs, inBounds);
2312 // If all indices are known integers and normalized, we can do a simple
2313 // check for the "inbounds" property.
2314 if (!Unknown && !inBounds &&
2315 isa<GlobalVariable>(C) && isInBoundsIndices(Idxs))
2316 return ConstantExpr::getInBoundsGetElementPtr(C, Idxs);
2321 Constant *llvm::ConstantFoldGetElementPtr(Constant *C,
2323 ArrayRef<Constant *> Idxs) {
2324 return ConstantFoldGetElementPtrImpl(C, inBounds, Idxs);
2327 Constant *llvm::ConstantFoldGetElementPtr(Constant *C,
2329 ArrayRef<Value *> Idxs) {
2330 return ConstantFoldGetElementPtrImpl(C, inBounds, Idxs);