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 // template-based folder for simple primitive constants like ConstantInt, and
16 // the special case hackery that we use to symbolically evaluate expressions
17 // that use ConstantExprs.
19 //===----------------------------------------------------------------------===//
21 #include "ConstantFold.h"
22 #include "llvm/Constants.h"
23 #include "llvm/Instructions.h"
24 #include "llvm/DerivedTypes.h"
25 #include "llvm/Function.h"
26 #include "llvm/GlobalAlias.h"
27 #include "llvm/ADT/SmallVector.h"
28 #include "llvm/Support/Compiler.h"
29 #include "llvm/Support/GetElementPtrTypeIterator.h"
30 #include "llvm/Support/ManagedStatic.h"
31 #include "llvm/Support/MathExtras.h"
35 //===----------------------------------------------------------------------===//
36 // ConstantFold*Instruction Implementations
37 //===----------------------------------------------------------------------===//
39 /// BitCastConstantVector - Convert the specified ConstantVector node to the
40 /// specified vector type. At this point, we know that the elements of the
41 /// input vector constant are all simple integer or FP values.
42 static Constant *BitCastConstantVector(ConstantVector *CV,
43 const VectorType *DstTy) {
44 // If this cast changes element count then we can't handle it here:
45 // doing so requires endianness information. This should be handled by
46 // Analysis/ConstantFolding.cpp
47 unsigned NumElts = DstTy->getNumElements();
48 if (NumElts != CV->getNumOperands())
51 // Check to verify that all elements of the input are simple.
52 for (unsigned i = 0; i != NumElts; ++i) {
53 if (!isa<ConstantInt>(CV->getOperand(i)) &&
54 !isa<ConstantFP>(CV->getOperand(i)))
58 // Bitcast each element now.
59 std::vector<Constant*> Result;
60 const Type *DstEltTy = DstTy->getElementType();
61 for (unsigned i = 0; i != NumElts; ++i)
62 Result.push_back(ConstantExpr::getBitCast(CV->getOperand(i), DstEltTy));
63 return ConstantVector::get(Result);
66 /// This function determines which opcode to use to fold two constant cast
67 /// expressions together. It uses CastInst::isEliminableCastPair to determine
68 /// the opcode. Consequently its just a wrapper around that function.
69 /// @brief Determine if it is valid to fold a cast of a cast
72 unsigned opc, ///< opcode of the second cast constant expression
73 const ConstantExpr*Op, ///< the first cast constant expression
74 const Type *DstTy ///< desintation type of the first cast
76 assert(Op && Op->isCast() && "Can't fold cast of cast without a cast!");
77 assert(DstTy && DstTy->isFirstClassType() && "Invalid cast destination type");
78 assert(CastInst::isCast(opc) && "Invalid cast opcode");
80 // The the types and opcodes for the two Cast constant expressions
81 const Type *SrcTy = Op->getOperand(0)->getType();
82 const Type *MidTy = Op->getType();
83 Instruction::CastOps firstOp = Instruction::CastOps(Op->getOpcode());
84 Instruction::CastOps secondOp = Instruction::CastOps(opc);
86 // Let CastInst::isEliminableCastPair do the heavy lifting.
87 return CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy, DstTy,
91 static Constant *FoldBitCast(Constant *V, const Type *DestTy) {
92 const Type *SrcTy = V->getType();
94 return V; // no-op cast
96 // Check to see if we are casting a pointer to an aggregate to a pointer to
97 // the first element. If so, return the appropriate GEP instruction.
98 if (const PointerType *PTy = dyn_cast<PointerType>(V->getType()))
99 if (const PointerType *DPTy = dyn_cast<PointerType>(DestTy))
100 if (PTy->getAddressSpace() == DPTy->getAddressSpace()) {
101 SmallVector<Value*, 8> IdxList;
102 IdxList.push_back(Constant::getNullValue(Type::Int32Ty));
103 const Type *ElTy = PTy->getElementType();
104 while (ElTy != DPTy->getElementType()) {
105 if (const StructType *STy = dyn_cast<StructType>(ElTy)) {
106 if (STy->getNumElements() == 0) break;
107 ElTy = STy->getElementType(0);
108 IdxList.push_back(Constant::getNullValue(Type::Int32Ty));
109 } else if (const SequentialType *STy =
110 dyn_cast<SequentialType>(ElTy)) {
111 if (isa<PointerType>(ElTy)) break; // Can't index into pointers!
112 ElTy = STy->getElementType();
113 IdxList.push_back(IdxList[0]);
119 if (ElTy == DPTy->getElementType())
120 return ConstantExpr::getGetElementPtr(V, &IdxList[0], IdxList.size());
123 // Handle casts from one vector constant to another. We know that the src
124 // and dest type have the same size (otherwise its an illegal cast).
125 if (const VectorType *DestPTy = dyn_cast<VectorType>(DestTy)) {
126 if (const VectorType *SrcTy = dyn_cast<VectorType>(V->getType())) {
127 assert(DestPTy->getBitWidth() == SrcTy->getBitWidth() &&
128 "Not cast between same sized vectors!");
130 // First, check for null. Undef is already handled.
131 if (isa<ConstantAggregateZero>(V))
132 return Constant::getNullValue(DestTy);
134 if (ConstantVector *CV = dyn_cast<ConstantVector>(V))
135 return BitCastConstantVector(CV, DestPTy);
138 // Canonicalize scalar-to-vector bitcasts into vector-to-vector bitcasts
139 // This allows for other simplifications (although some of them
140 // can only be handled by Analysis/ConstantFolding.cpp).
141 if (isa<ConstantInt>(V) || isa<ConstantFP>(V))
142 return ConstantExpr::getBitCast(ConstantVector::get(&V, 1), DestPTy);
145 // Finally, implement bitcast folding now. The code below doesn't handle
147 if (isa<ConstantPointerNull>(V)) // ptr->ptr cast.
148 return ConstantPointerNull::get(cast<PointerType>(DestTy));
150 // Handle integral constant input.
151 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
152 if (DestTy->isInteger())
153 // Integral -> Integral. This is a no-op because the bit widths must
154 // be the same. Consequently, we just fold to V.
157 if (DestTy->isFloatingPoint())
158 return ConstantFP::get(APFloat(CI->getValue(),
159 DestTy != Type::PPC_FP128Ty));
161 // Otherwise, can't fold this (vector?)
165 // Handle ConstantFP input.
166 if (const ConstantFP *FP = dyn_cast<ConstantFP>(V))
168 return ConstantInt::get(FP->getValueAPF().bitcastToAPInt());
174 Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
175 const Type *DestTy) {
176 if (isa<UndefValue>(V)) {
177 // zext(undef) = 0, because the top bits will be zero.
178 // sext(undef) = 0, because the top bits will all be the same.
179 // [us]itofp(undef) = 0, because the result value is bounded.
180 if (opc == Instruction::ZExt || opc == Instruction::SExt ||
181 opc == Instruction::UIToFP || opc == Instruction::SIToFP)
182 return Constant::getNullValue(DestTy);
183 return UndefValue::get(DestTy);
185 // No compile-time operations on this type yet.
186 if (V->getType() == Type::PPC_FP128Ty || DestTy == Type::PPC_FP128Ty)
189 // If the cast operand is a constant expression, there's a few things we can
190 // do to try to simplify it.
191 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
193 // Try hard to fold cast of cast because they are often eliminable.
194 if (unsigned newOpc = foldConstantCastPair(opc, CE, DestTy))
195 return ConstantExpr::getCast(newOpc, CE->getOperand(0), DestTy);
196 } else if (CE->getOpcode() == Instruction::GetElementPtr) {
197 // If all of the indexes in the GEP are null values, there is no pointer
198 // adjustment going on. We might as well cast the source pointer.
199 bool isAllNull = true;
200 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
201 if (!CE->getOperand(i)->isNullValue()) {
206 // This is casting one pointer type to another, always BitCast
207 return ConstantExpr::getPointerCast(CE->getOperand(0), DestTy);
211 // If the cast operand is a constant vector, perform the cast by
212 // operating on each element. In the cast of bitcasts, the element
213 // count may be mismatched; don't attempt to handle that here.
214 if (const ConstantVector *CV = dyn_cast<ConstantVector>(V))
215 if (isa<VectorType>(DestTy) &&
216 cast<VectorType>(DestTy)->getNumElements() ==
217 CV->getType()->getNumElements()) {
218 std::vector<Constant*> res;
219 const VectorType *DestVecTy = cast<VectorType>(DestTy);
220 const Type *DstEltTy = DestVecTy->getElementType();
221 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
222 res.push_back(ConstantExpr::getCast(opc,
223 CV->getOperand(i), DstEltTy));
224 return ConstantVector::get(DestVecTy, res);
227 // We actually have to do a cast now. Perform the cast according to the
230 case Instruction::FPTrunc:
231 case Instruction::FPExt:
232 if (const ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
234 APFloat Val = FPC->getValueAPF();
235 Val.convert(DestTy == Type::FloatTy ? APFloat::IEEEsingle :
236 DestTy == Type::DoubleTy ? APFloat::IEEEdouble :
237 DestTy == Type::X86_FP80Ty ? APFloat::x87DoubleExtended :
238 DestTy == Type::FP128Ty ? APFloat::IEEEquad :
240 APFloat::rmNearestTiesToEven, &ignored);
241 return ConstantFP::get(Val);
243 return 0; // Can't fold.
244 case Instruction::FPToUI:
245 case Instruction::FPToSI:
246 if (const ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
247 const APFloat &V = FPC->getValueAPF();
250 uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
251 (void) V.convertToInteger(x, DestBitWidth, opc==Instruction::FPToSI,
252 APFloat::rmTowardZero, &ignored);
253 APInt Val(DestBitWidth, 2, x);
254 return ConstantInt::get(Val);
256 return 0; // Can't fold.
257 case Instruction::IntToPtr: //always treated as unsigned
258 if (V->isNullValue()) // Is it an integral null value?
259 return ConstantPointerNull::get(cast<PointerType>(DestTy));
260 return 0; // Other pointer types cannot be casted
261 case Instruction::PtrToInt: // always treated as unsigned
262 if (V->isNullValue()) // is it a null pointer value?
263 return ConstantInt::get(DestTy, 0);
264 return 0; // Other pointer types cannot be casted
265 case Instruction::UIToFP:
266 case Instruction::SIToFP:
267 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
268 APInt api = CI->getValue();
269 const uint64_t zero[] = {0, 0};
270 APFloat apf = APFloat(APInt(DestTy->getPrimitiveSizeInBits(),
272 (void)apf.convertFromAPInt(api,
273 opc==Instruction::SIToFP,
274 APFloat::rmNearestTiesToEven);
275 return ConstantFP::get(apf);
278 case Instruction::ZExt:
279 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
280 uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
281 APInt Result(CI->getValue());
282 Result.zext(BitWidth);
283 return ConstantInt::get(Result);
286 case Instruction::SExt:
287 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
288 uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
289 APInt Result(CI->getValue());
290 Result.sext(BitWidth);
291 return ConstantInt::get(Result);
294 case Instruction::Trunc:
295 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
296 uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
297 APInt Result(CI->getValue());
298 Result.trunc(BitWidth);
299 return ConstantInt::get(Result);
302 case Instruction::BitCast:
303 return FoldBitCast(const_cast<Constant*>(V), DestTy);
305 assert(!"Invalid CE CastInst opcode");
309 assert(0 && "Failed to cast constant expression");
313 Constant *llvm::ConstantFoldSelectInstruction(const Constant *Cond,
315 const Constant *V2) {
316 if (const ConstantInt *CB = dyn_cast<ConstantInt>(Cond))
317 return const_cast<Constant*>(CB->getZExtValue() ? V1 : V2);
319 if (isa<UndefValue>(V1)) return const_cast<Constant*>(V2);
320 if (isa<UndefValue>(V2)) return const_cast<Constant*>(V1);
321 if (isa<UndefValue>(Cond)) return const_cast<Constant*>(V1);
322 if (V1 == V2) return const_cast<Constant*>(V1);
326 Constant *llvm::ConstantFoldExtractElementInstruction(const Constant *Val,
327 const Constant *Idx) {
328 if (isa<UndefValue>(Val)) // ee(undef, x) -> undef
329 return UndefValue::get(cast<VectorType>(Val->getType())->getElementType());
330 if (Val->isNullValue()) // ee(zero, x) -> zero
331 return Constant::getNullValue(
332 cast<VectorType>(Val->getType())->getElementType());
334 if (const ConstantVector *CVal = dyn_cast<ConstantVector>(Val)) {
335 if (const ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx)) {
336 return CVal->getOperand(CIdx->getZExtValue());
337 } else if (isa<UndefValue>(Idx)) {
338 // ee({w,x,y,z}, undef) -> w (an arbitrary value).
339 return CVal->getOperand(0);
345 Constant *llvm::ConstantFoldInsertElementInstruction(const Constant *Val,
347 const Constant *Idx) {
348 const ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx);
350 APInt idxVal = CIdx->getValue();
351 if (isa<UndefValue>(Val)) {
352 // Insertion of scalar constant into vector undef
353 // Optimize away insertion of undef
354 if (isa<UndefValue>(Elt))
355 return const_cast<Constant*>(Val);
356 // Otherwise break the aggregate undef into multiple undefs and do
359 cast<VectorType>(Val->getType())->getNumElements();
360 std::vector<Constant*> Ops;
362 for (unsigned i = 0; i < numOps; ++i) {
364 (idxVal == i) ? Elt : UndefValue::get(Elt->getType());
365 Ops.push_back(const_cast<Constant*>(Op));
367 return ConstantVector::get(Ops);
369 if (isa<ConstantAggregateZero>(Val)) {
370 // Insertion of scalar constant into vector aggregate zero
371 // Optimize away insertion of zero
372 if (Elt->isNullValue())
373 return const_cast<Constant*>(Val);
374 // Otherwise break the aggregate zero into multiple zeros and do
377 cast<VectorType>(Val->getType())->getNumElements();
378 std::vector<Constant*> Ops;
380 for (unsigned i = 0; i < numOps; ++i) {
382 (idxVal == i) ? Elt : Constant::getNullValue(Elt->getType());
383 Ops.push_back(const_cast<Constant*>(Op));
385 return ConstantVector::get(Ops);
387 if (const ConstantVector *CVal = dyn_cast<ConstantVector>(Val)) {
388 // Insertion of scalar constant into vector constant
389 std::vector<Constant*> Ops;
390 Ops.reserve(CVal->getNumOperands());
391 for (unsigned i = 0; i < CVal->getNumOperands(); ++i) {
393 (idxVal == i) ? Elt : cast<Constant>(CVal->getOperand(i));
394 Ops.push_back(const_cast<Constant*>(Op));
396 return ConstantVector::get(Ops);
402 /// GetVectorElement - If C is a ConstantVector, ConstantAggregateZero or Undef
403 /// return the specified element value. Otherwise return null.
404 static Constant *GetVectorElement(const Constant *C, unsigned EltNo) {
405 if (const ConstantVector *CV = dyn_cast<ConstantVector>(C))
406 return CV->getOperand(EltNo);
408 const Type *EltTy = cast<VectorType>(C->getType())->getElementType();
409 if (isa<ConstantAggregateZero>(C))
410 return Constant::getNullValue(EltTy);
411 if (isa<UndefValue>(C))
412 return UndefValue::get(EltTy);
416 Constant *llvm::ConstantFoldShuffleVectorInstruction(const Constant *V1,
418 const Constant *Mask) {
419 // Undefined shuffle mask -> undefined value.
420 if (isa<UndefValue>(Mask)) return UndefValue::get(V1->getType());
422 unsigned MaskNumElts = cast<VectorType>(Mask->getType())->getNumElements();
423 unsigned SrcNumElts = cast<VectorType>(V1->getType())->getNumElements();
424 const Type *EltTy = cast<VectorType>(V1->getType())->getElementType();
426 // Loop over the shuffle mask, evaluating each element.
427 SmallVector<Constant*, 32> Result;
428 for (unsigned i = 0; i != MaskNumElts; ++i) {
429 Constant *InElt = GetVectorElement(Mask, i);
430 if (InElt == 0) return 0;
432 if (isa<UndefValue>(InElt))
433 InElt = UndefValue::get(EltTy);
434 else if (ConstantInt *CI = dyn_cast<ConstantInt>(InElt)) {
435 unsigned Elt = CI->getZExtValue();
436 if (Elt >= SrcNumElts*2)
437 InElt = UndefValue::get(EltTy);
438 else if (Elt >= SrcNumElts)
439 InElt = GetVectorElement(V2, Elt - SrcNumElts);
441 InElt = GetVectorElement(V1, Elt);
442 if (InElt == 0) return 0;
447 Result.push_back(InElt);
450 return ConstantVector::get(&Result[0], Result.size());
453 Constant *llvm::ConstantFoldExtractValueInstruction(const Constant *Agg,
454 const unsigned *Idxs,
456 // Base case: no indices, so return the entire value.
458 return const_cast<Constant *>(Agg);
460 if (isa<UndefValue>(Agg)) // ev(undef, x) -> undef
461 return UndefValue::get(ExtractValueInst::getIndexedType(Agg->getType(),
465 if (isa<ConstantAggregateZero>(Agg)) // ev(0, x) -> 0
467 Constant::getNullValue(ExtractValueInst::getIndexedType(Agg->getType(),
471 // Otherwise recurse.
472 return ConstantFoldExtractValueInstruction(Agg->getOperand(*Idxs),
476 Constant *llvm::ConstantFoldInsertValueInstruction(const Constant *Agg,
478 const unsigned *Idxs,
480 // Base case: no indices, so replace the entire value.
482 return const_cast<Constant *>(Val);
484 if (isa<UndefValue>(Agg)) {
485 // Insertion of constant into aggregate undef
486 // Optimize away insertion of undef
487 if (isa<UndefValue>(Val))
488 return const_cast<Constant*>(Agg);
489 // Otherwise break the aggregate undef into multiple undefs and do
491 const CompositeType *AggTy = cast<CompositeType>(Agg->getType());
493 if (const ArrayType *AR = dyn_cast<ArrayType>(AggTy))
494 numOps = AR->getNumElements();
496 numOps = cast<StructType>(AggTy)->getNumElements();
497 std::vector<Constant*> Ops(numOps);
498 for (unsigned i = 0; i < numOps; ++i) {
499 const Type *MemberTy = AggTy->getTypeAtIndex(i);
502 ConstantFoldInsertValueInstruction(UndefValue::get(MemberTy),
503 Val, Idxs+1, NumIdx-1) :
504 UndefValue::get(MemberTy);
505 Ops[i] = const_cast<Constant*>(Op);
507 if (isa<StructType>(AggTy))
508 return ConstantStruct::get(Ops);
510 return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
512 if (isa<ConstantAggregateZero>(Agg)) {
513 // Insertion of constant into aggregate zero
514 // Optimize away insertion of zero
515 if (Val->isNullValue())
516 return const_cast<Constant*>(Agg);
517 // Otherwise break the aggregate zero into multiple zeros and do
519 const CompositeType *AggTy = cast<CompositeType>(Agg->getType());
521 if (const ArrayType *AR = dyn_cast<ArrayType>(AggTy))
522 numOps = AR->getNumElements();
524 numOps = cast<StructType>(AggTy)->getNumElements();
525 std::vector<Constant*> Ops(numOps);
526 for (unsigned i = 0; i < numOps; ++i) {
527 const Type *MemberTy = AggTy->getTypeAtIndex(i);
530 ConstantFoldInsertValueInstruction(Constant::getNullValue(MemberTy),
531 Val, Idxs+1, NumIdx-1) :
532 Constant::getNullValue(MemberTy);
533 Ops[i] = const_cast<Constant*>(Op);
535 if (isa<StructType>(AggTy))
536 return ConstantStruct::get(Ops);
538 return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
540 if (isa<ConstantStruct>(Agg) || isa<ConstantArray>(Agg)) {
541 // Insertion of constant into aggregate constant
542 std::vector<Constant*> Ops(Agg->getNumOperands());
543 for (unsigned i = 0; i < Agg->getNumOperands(); ++i) {
546 ConstantFoldInsertValueInstruction(Agg->getOperand(i),
547 Val, Idxs+1, NumIdx-1) :
549 Ops[i] = const_cast<Constant*>(Op);
552 if (isa<StructType>(Agg->getType()))
553 C = ConstantStruct::get(Ops);
555 C = ConstantArray::get(cast<ArrayType>(Agg->getType()), Ops);
562 /// EvalVectorOp - Given two vector constants and a function pointer, apply the
563 /// function pointer to each element pair, producing a new ConstantVector
564 /// constant. Either or both of V1 and V2 may be NULL, meaning a
565 /// ConstantAggregateZero operand.
566 static Constant *EvalVectorOp(const ConstantVector *V1,
567 const ConstantVector *V2,
568 const VectorType *VTy,
569 Constant *(*FP)(Constant*, Constant*)) {
570 std::vector<Constant*> Res;
571 const Type *EltTy = VTy->getElementType();
572 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
573 const Constant *C1 = V1 ? V1->getOperand(i) : Constant::getNullValue(EltTy);
574 const Constant *C2 = V2 ? V2->getOperand(i) : Constant::getNullValue(EltTy);
575 Res.push_back(FP(const_cast<Constant*>(C1),
576 const_cast<Constant*>(C2)));
578 return ConstantVector::get(Res);
581 Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
583 const Constant *C2) {
584 // No compile-time operations on this type yet.
585 if (C1->getType() == Type::PPC_FP128Ty)
588 // Handle UndefValue up front
589 if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
591 case Instruction::Xor:
592 if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
593 // Handle undef ^ undef -> 0 special case. This is a common
595 return Constant::getNullValue(C1->getType());
597 case Instruction::Add:
598 case Instruction::Sub:
599 return UndefValue::get(C1->getType());
600 case Instruction::Mul:
601 case Instruction::And:
602 return Constant::getNullValue(C1->getType());
603 case Instruction::UDiv:
604 case Instruction::SDiv:
605 case Instruction::URem:
606 case Instruction::SRem:
607 if (!isa<UndefValue>(C2)) // undef / X -> 0
608 return Constant::getNullValue(C1->getType());
609 return const_cast<Constant*>(C2); // X / undef -> undef
610 case Instruction::Or: // X | undef -> -1
611 if (const VectorType *PTy = dyn_cast<VectorType>(C1->getType()))
612 return ConstantVector::getAllOnesValue(PTy);
613 return ConstantInt::getAllOnesValue(C1->getType());
614 case Instruction::LShr:
615 if (isa<UndefValue>(C2) && isa<UndefValue>(C1))
616 return const_cast<Constant*>(C1); // undef lshr undef -> undef
617 return Constant::getNullValue(C1->getType()); // X lshr undef -> 0
619 case Instruction::AShr:
620 if (!isa<UndefValue>(C2))
621 return const_cast<Constant*>(C1); // undef ashr X --> undef
622 else if (isa<UndefValue>(C1))
623 return const_cast<Constant*>(C1); // undef ashr undef -> undef
625 return const_cast<Constant*>(C1); // X ashr undef --> X
626 case Instruction::Shl:
627 // undef << X -> 0 or X << undef -> 0
628 return Constant::getNullValue(C1->getType());
632 // Handle simplifications of the RHS when a constant int.
633 if (const ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
635 case Instruction::Add:
636 if (CI2->equalsInt(0)) return const_cast<Constant*>(C1); // X + 0 == X
638 case Instruction::Sub:
639 if (CI2->equalsInt(0)) return const_cast<Constant*>(C1); // X - 0 == X
641 case Instruction::Mul:
642 if (CI2->equalsInt(0)) return const_cast<Constant*>(C2); // X * 0 == 0
643 if (CI2->equalsInt(1))
644 return const_cast<Constant*>(C1); // X * 1 == X
646 case Instruction::UDiv:
647 case Instruction::SDiv:
648 if (CI2->equalsInt(1))
649 return const_cast<Constant*>(C1); // X / 1 == X
650 if (CI2->equalsInt(0))
651 return UndefValue::get(CI2->getType()); // X / 0 == undef
653 case Instruction::URem:
654 case Instruction::SRem:
655 if (CI2->equalsInt(1))
656 return Constant::getNullValue(CI2->getType()); // X % 1 == 0
657 if (CI2->equalsInt(0))
658 return UndefValue::get(CI2->getType()); // X % 0 == undef
660 case Instruction::And:
661 if (CI2->isZero()) return const_cast<Constant*>(C2); // X & 0 == 0
662 if (CI2->isAllOnesValue())
663 return const_cast<Constant*>(C1); // X & -1 == X
665 if (const ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
666 // (zext i32 to i64) & 4294967295 -> (zext i32 to i64)
667 if (CE1->getOpcode() == Instruction::ZExt) {
668 unsigned DstWidth = CI2->getType()->getBitWidth();
670 CE1->getOperand(0)->getType()->getPrimitiveSizeInBits();
671 APInt PossiblySetBits(APInt::getLowBitsSet(DstWidth, SrcWidth));
672 if ((PossiblySetBits & CI2->getValue()) == PossiblySetBits)
673 return const_cast<Constant*>(C1);
676 // If and'ing the address of a global with a constant, fold it.
677 if (CE1->getOpcode() == Instruction::PtrToInt &&
678 isa<GlobalValue>(CE1->getOperand(0))) {
679 GlobalValue *GV = cast<GlobalValue>(CE1->getOperand(0));
681 // Functions are at least 4-byte aligned.
682 unsigned GVAlign = GV->getAlignment();
683 if (isa<Function>(GV))
684 GVAlign = std::max(GVAlign, 4U);
687 unsigned DstWidth = CI2->getType()->getBitWidth();
688 unsigned SrcWidth = std::min(DstWidth, Log2_32(GVAlign));
689 APInt BitsNotSet(APInt::getLowBitsSet(DstWidth, SrcWidth));
691 // If checking bits we know are clear, return zero.
692 if ((CI2->getValue() & BitsNotSet) == CI2->getValue())
693 return Constant::getNullValue(CI2->getType());
698 case Instruction::Or:
699 if (CI2->equalsInt(0)) return const_cast<Constant*>(C1); // X | 0 == X
700 if (CI2->isAllOnesValue())
701 return const_cast<Constant*>(C2); // X | -1 == -1
703 case Instruction::Xor:
704 if (CI2->equalsInt(0)) return const_cast<Constant*>(C1); // X ^ 0 == X
706 case Instruction::AShr:
707 // ashr (zext C to Ty), C2 -> lshr (zext C, CSA), C2
708 if (const ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1))
709 if (CE1->getOpcode() == Instruction::ZExt) // Top bits known zero.
710 return ConstantExpr::getLShr(const_cast<Constant*>(C1),
711 const_cast<Constant*>(C2));
716 // At this point we know neither constant is an UndefValue.
717 if (const ConstantInt *CI1 = dyn_cast<ConstantInt>(C1)) {
718 if (const ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
719 using namespace APIntOps;
720 const APInt &C1V = CI1->getValue();
721 const APInt &C2V = CI2->getValue();
725 case Instruction::Add:
726 return ConstantInt::get(C1V + C2V);
727 case Instruction::Sub:
728 return ConstantInt::get(C1V - C2V);
729 case Instruction::Mul:
730 return ConstantInt::get(C1V * C2V);
731 case Instruction::UDiv:
732 assert(!CI2->isNullValue() && "Div by zero handled above");
733 return ConstantInt::get(C1V.udiv(C2V));
734 case Instruction::SDiv:
735 assert(!CI2->isNullValue() && "Div by zero handled above");
736 if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
737 return UndefValue::get(CI1->getType()); // MIN_INT / -1 -> undef
738 return ConstantInt::get(C1V.sdiv(C2V));
739 case Instruction::URem:
740 assert(!CI2->isNullValue() && "Div by zero handled above");
741 return ConstantInt::get(C1V.urem(C2V));
742 case Instruction::SRem:
743 assert(!CI2->isNullValue() && "Div by zero handled above");
744 if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
745 return UndefValue::get(CI1->getType()); // MIN_INT % -1 -> undef
746 return ConstantInt::get(C1V.srem(C2V));
747 case Instruction::And:
748 return ConstantInt::get(C1V & C2V);
749 case Instruction::Or:
750 return ConstantInt::get(C1V | C2V);
751 case Instruction::Xor:
752 return ConstantInt::get(C1V ^ C2V);
753 case Instruction::Shl: {
754 uint32_t shiftAmt = C2V.getZExtValue();
755 if (shiftAmt < C1V.getBitWidth())
756 return ConstantInt::get(C1V.shl(shiftAmt));
758 return UndefValue::get(C1->getType()); // too big shift is undef
760 case Instruction::LShr: {
761 uint32_t shiftAmt = C2V.getZExtValue();
762 if (shiftAmt < C1V.getBitWidth())
763 return ConstantInt::get(C1V.lshr(shiftAmt));
765 return UndefValue::get(C1->getType()); // too big shift is undef
767 case Instruction::AShr: {
768 uint32_t shiftAmt = C2V.getZExtValue();
769 if (shiftAmt < C1V.getBitWidth())
770 return ConstantInt::get(C1V.ashr(shiftAmt));
772 return UndefValue::get(C1->getType()); // too big shift is undef
776 } else if (const ConstantFP *CFP1 = dyn_cast<ConstantFP>(C1)) {
777 if (const ConstantFP *CFP2 = dyn_cast<ConstantFP>(C2)) {
778 APFloat C1V = CFP1->getValueAPF();
779 APFloat C2V = CFP2->getValueAPF();
780 APFloat C3V = C1V; // copy for modification
784 case Instruction::FAdd:
785 (void)C3V.add(C2V, APFloat::rmNearestTiesToEven);
786 return ConstantFP::get(C3V);
787 case Instruction::FSub:
788 (void)C3V.subtract(C2V, APFloat::rmNearestTiesToEven);
789 return ConstantFP::get(C3V);
790 case Instruction::FMul:
791 (void)C3V.multiply(C2V, APFloat::rmNearestTiesToEven);
792 return ConstantFP::get(C3V);
793 case Instruction::FDiv:
794 (void)C3V.divide(C2V, APFloat::rmNearestTiesToEven);
795 return ConstantFP::get(C3V);
796 case Instruction::FRem:
797 (void)C3V.mod(C2V, APFloat::rmNearestTiesToEven);
798 return ConstantFP::get(C3V);
801 } else if (const VectorType *VTy = dyn_cast<VectorType>(C1->getType())) {
802 const ConstantVector *CP1 = dyn_cast<ConstantVector>(C1);
803 const ConstantVector *CP2 = dyn_cast<ConstantVector>(C2);
804 if ((CP1 != NULL || isa<ConstantAggregateZero>(C1)) &&
805 (CP2 != NULL || isa<ConstantAggregateZero>(C2))) {
809 case Instruction::Add:
810 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getAdd);
811 case Instruction::FAdd:
812 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getFAdd);
813 case Instruction::Sub:
814 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getSub);
815 case Instruction::FSub:
816 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getFSub);
817 case Instruction::Mul:
818 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getMul);
819 case Instruction::FMul:
820 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getFMul);
821 case Instruction::UDiv:
822 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getUDiv);
823 case Instruction::SDiv:
824 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getSDiv);
825 case Instruction::FDiv:
826 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getFDiv);
827 case Instruction::URem:
828 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getURem);
829 case Instruction::SRem:
830 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getSRem);
831 case Instruction::FRem:
832 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getFRem);
833 case Instruction::And:
834 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getAnd);
835 case Instruction::Or:
836 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getOr);
837 case Instruction::Xor:
838 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getXor);
839 case Instruction::LShr:
840 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getLShr);
841 case Instruction::AShr:
842 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getAShr);
843 case Instruction::Shl:
844 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getShl);
849 if (isa<ConstantExpr>(C1)) {
850 // There are many possible foldings we could do here. We should probably
851 // at least fold add of a pointer with an integer into the appropriate
852 // getelementptr. This will improve alias analysis a bit.
853 } else if (isa<ConstantExpr>(C2)) {
854 // If C2 is a constant expr and C1 isn't, flop them around and fold the
855 // other way if possible.
857 case Instruction::Add:
858 case Instruction::FAdd:
859 case Instruction::Mul:
860 case Instruction::FMul:
861 case Instruction::And:
862 case Instruction::Or:
863 case Instruction::Xor:
864 // No change of opcode required.
865 return ConstantFoldBinaryInstruction(Opcode, C2, C1);
867 case Instruction::Shl:
868 case Instruction::LShr:
869 case Instruction::AShr:
870 case Instruction::Sub:
871 case Instruction::FSub:
872 case Instruction::SDiv:
873 case Instruction::UDiv:
874 case Instruction::FDiv:
875 case Instruction::URem:
876 case Instruction::SRem:
877 case Instruction::FRem:
878 default: // These instructions cannot be flopped around.
883 // We don't know how to fold this.
887 /// isZeroSizedType - This type is zero sized if its an array or structure of
888 /// zero sized types. The only leaf zero sized type is an empty structure.
889 static bool isMaybeZeroSizedType(const Type *Ty) {
890 if (isa<OpaqueType>(Ty)) return true; // Can't say.
891 if (const StructType *STy = dyn_cast<StructType>(Ty)) {
893 // If all of elements have zero size, this does too.
894 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
895 if (!isMaybeZeroSizedType(STy->getElementType(i))) return false;
898 } else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
899 return isMaybeZeroSizedType(ATy->getElementType());
904 /// IdxCompare - Compare the two constants as though they were getelementptr
905 /// indices. This allows coersion of the types to be the same thing.
907 /// If the two constants are the "same" (after coersion), return 0. If the
908 /// first is less than the second, return -1, if the second is less than the
909 /// first, return 1. If the constants are not integral, return -2.
911 static int IdxCompare(Constant *C1, Constant *C2, const Type *ElTy) {
912 if (C1 == C2) return 0;
914 // Ok, we found a different index. If they are not ConstantInt, we can't do
915 // anything with them.
916 if (!isa<ConstantInt>(C1) || !isa<ConstantInt>(C2))
917 return -2; // don't know!
919 // Ok, we have two differing integer indices. Sign extend them to be the same
920 // type. Long is always big enough, so we use it.
921 if (C1->getType() != Type::Int64Ty)
922 C1 = ConstantExpr::getSExt(C1, Type::Int64Ty);
924 if (C2->getType() != Type::Int64Ty)
925 C2 = ConstantExpr::getSExt(C2, Type::Int64Ty);
927 if (C1 == C2) return 0; // They are equal
929 // If the type being indexed over is really just a zero sized type, there is
930 // no pointer difference being made here.
931 if (isMaybeZeroSizedType(ElTy))
934 // If they are really different, now that they are the same type, then we
935 // found a difference!
936 if (cast<ConstantInt>(C1)->getSExtValue() <
937 cast<ConstantInt>(C2)->getSExtValue())
943 /// evaluateFCmpRelation - This function determines if there is anything we can
944 /// decide about the two constants provided. This doesn't need to handle simple
945 /// things like ConstantFP comparisons, but should instead handle ConstantExprs.
946 /// If we can determine that the two constants have a particular relation to
947 /// each other, we should return the corresponding FCmpInst predicate,
948 /// otherwise return FCmpInst::BAD_FCMP_PREDICATE. This is used below in
949 /// ConstantFoldCompareInstruction.
951 /// To simplify this code we canonicalize the relation so that the first
952 /// operand is always the most "complex" of the two. We consider ConstantFP
953 /// to be the simplest, and ConstantExprs to be the most complex.
954 static FCmpInst::Predicate evaluateFCmpRelation(const Constant *V1,
955 const Constant *V2) {
956 assert(V1->getType() == V2->getType() &&
957 "Cannot compare values of different types!");
959 // No compile-time operations on this type yet.
960 if (V1->getType() == Type::PPC_FP128Ty)
961 return FCmpInst::BAD_FCMP_PREDICATE;
963 // Handle degenerate case quickly
964 if (V1 == V2) return FCmpInst::FCMP_OEQ;
966 if (!isa<ConstantExpr>(V1)) {
967 if (!isa<ConstantExpr>(V2)) {
968 // We distilled thisUse the standard constant folder for a few cases
970 Constant *C1 = const_cast<Constant*>(V1);
971 Constant *C2 = const_cast<Constant*>(V2);
972 R = dyn_cast<ConstantInt>(
973 ConstantExpr::getFCmp(FCmpInst::FCMP_OEQ, C1, C2));
974 if (R && !R->isZero())
975 return FCmpInst::FCMP_OEQ;
976 R = dyn_cast<ConstantInt>(
977 ConstantExpr::getFCmp(FCmpInst::FCMP_OLT, C1, C2));
978 if (R && !R->isZero())
979 return FCmpInst::FCMP_OLT;
980 R = dyn_cast<ConstantInt>(
981 ConstantExpr::getFCmp(FCmpInst::FCMP_OGT, C1, C2));
982 if (R && !R->isZero())
983 return FCmpInst::FCMP_OGT;
985 // Nothing more we can do
986 return FCmpInst::BAD_FCMP_PREDICATE;
989 // If the first operand is simple and second is ConstantExpr, swap operands.
990 FCmpInst::Predicate SwappedRelation = evaluateFCmpRelation(V2, V1);
991 if (SwappedRelation != FCmpInst::BAD_FCMP_PREDICATE)
992 return FCmpInst::getSwappedPredicate(SwappedRelation);
994 // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
995 // constantexpr or a simple constant.
996 const ConstantExpr *CE1 = cast<ConstantExpr>(V1);
997 switch (CE1->getOpcode()) {
998 case Instruction::FPTrunc:
999 case Instruction::FPExt:
1000 case Instruction::UIToFP:
1001 case Instruction::SIToFP:
1002 // We might be able to do something with these but we don't right now.
1008 // There are MANY other foldings that we could perform here. They will
1009 // probably be added on demand, as they seem needed.
1010 return FCmpInst::BAD_FCMP_PREDICATE;
1013 /// evaluateICmpRelation - This function determines if there is anything we can
1014 /// decide about the two constants provided. This doesn't need to handle simple
1015 /// things like integer comparisons, but should instead handle ConstantExprs
1016 /// and GlobalValues. If we can determine that the two constants have a
1017 /// particular relation to each other, we should return the corresponding ICmp
1018 /// predicate, otherwise return ICmpInst::BAD_ICMP_PREDICATE.
1020 /// To simplify this code we canonicalize the relation so that the first
1021 /// operand is always the most "complex" of the two. We consider simple
1022 /// constants (like ConstantInt) to be the simplest, followed by
1023 /// GlobalValues, followed by ConstantExpr's (the most complex).
1025 static ICmpInst::Predicate evaluateICmpRelation(const Constant *V1,
1028 assert(V1->getType() == V2->getType() &&
1029 "Cannot compare different types of values!");
1030 if (V1 == V2) return ICmpInst::ICMP_EQ;
1032 if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1)) {
1033 if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2)) {
1034 // We distilled this down to a simple case, use the standard constant
1037 Constant *C1 = const_cast<Constant*>(V1);
1038 Constant *C2 = const_cast<Constant*>(V2);
1039 ICmpInst::Predicate pred = ICmpInst::ICMP_EQ;
1040 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, C1, C2));
1041 if (R && !R->isZero())
1043 pred = isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1044 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, C1, C2));
1045 if (R && !R->isZero())
1047 pred = isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1048 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, C1, C2));
1049 if (R && !R->isZero())
1052 // If we couldn't figure it out, bail.
1053 return ICmpInst::BAD_ICMP_PREDICATE;
1056 // If the first operand is simple, swap operands.
1057 ICmpInst::Predicate SwappedRelation =
1058 evaluateICmpRelation(V2, V1, isSigned);
1059 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1060 return ICmpInst::getSwappedPredicate(SwappedRelation);
1062 } else if (const GlobalValue *CPR1 = dyn_cast<GlobalValue>(V1)) {
1063 if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1064 ICmpInst::Predicate SwappedRelation =
1065 evaluateICmpRelation(V2, V1, isSigned);
1066 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1067 return ICmpInst::getSwappedPredicate(SwappedRelation);
1069 return ICmpInst::BAD_ICMP_PREDICATE;
1072 // Now we know that the RHS is a GlobalValue or simple constant,
1073 // which (since the types must match) means that it's a ConstantPointerNull.
1074 if (const GlobalValue *CPR2 = dyn_cast<GlobalValue>(V2)) {
1075 // Don't try to decide equality of aliases.
1076 if (!isa<GlobalAlias>(CPR1) && !isa<GlobalAlias>(CPR2))
1077 if (!CPR1->hasExternalWeakLinkage() || !CPR2->hasExternalWeakLinkage())
1078 return ICmpInst::ICMP_NE;
1080 assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!");
1081 // GlobalVals can never be null. Don't try to evaluate aliases.
1082 if (!CPR1->hasExternalWeakLinkage() && !isa<GlobalAlias>(CPR1))
1083 return ICmpInst::ICMP_NE;
1086 // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1087 // constantexpr, a CPR, or a simple constant.
1088 const ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1089 const Constant *CE1Op0 = CE1->getOperand(0);
1091 switch (CE1->getOpcode()) {
1092 case Instruction::Trunc:
1093 case Instruction::FPTrunc:
1094 case Instruction::FPExt:
1095 case Instruction::FPToUI:
1096 case Instruction::FPToSI:
1097 break; // We can't evaluate floating point casts or truncations.
1099 case Instruction::UIToFP:
1100 case Instruction::SIToFP:
1101 case Instruction::BitCast:
1102 case Instruction::ZExt:
1103 case Instruction::SExt:
1104 // If the cast is not actually changing bits, and the second operand is a
1105 // null pointer, do the comparison with the pre-casted value.
1106 if (V2->isNullValue() &&
1107 (isa<PointerType>(CE1->getType()) || CE1->getType()->isInteger())) {
1108 bool sgnd = isSigned;
1109 if (CE1->getOpcode() == Instruction::ZExt) isSigned = false;
1110 if (CE1->getOpcode() == Instruction::SExt) isSigned = true;
1111 return evaluateICmpRelation(CE1Op0,
1112 Constant::getNullValue(CE1Op0->getType()),
1116 // If the dest type is a pointer type, and the RHS is a constantexpr cast
1117 // from the same type as the src of the LHS, evaluate the inputs. This is
1118 // important for things like "icmp eq (cast 4 to int*), (cast 5 to int*)",
1119 // which happens a lot in compilers with tagged integers.
1120 if (const ConstantExpr *CE2 = dyn_cast<ConstantExpr>(V2))
1121 if (CE2->isCast() && isa<PointerType>(CE1->getType()) &&
1122 CE1->getOperand(0)->getType() == CE2->getOperand(0)->getType() &&
1123 CE1->getOperand(0)->getType()->isInteger()) {
1124 bool sgnd = isSigned;
1125 if (CE1->getOpcode() == Instruction::ZExt) isSigned = false;
1126 if (CE1->getOpcode() == Instruction::SExt) isSigned = true;
1127 return evaluateICmpRelation(CE1->getOperand(0), CE2->getOperand(0),
1132 case Instruction::GetElementPtr:
1133 // Ok, since this is a getelementptr, we know that the constant has a
1134 // pointer type. Check the various cases.
1135 if (isa<ConstantPointerNull>(V2)) {
1136 // If we are comparing a GEP to a null pointer, check to see if the base
1137 // of the GEP equals the null pointer.
1138 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1139 if (GV->hasExternalWeakLinkage())
1140 // Weak linkage GVals could be zero or not. We're comparing that
1141 // to null pointer so its greater-or-equal
1142 return isSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE;
1144 // If its not weak linkage, the GVal must have a non-zero address
1145 // so the result is greater-than
1146 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1147 } else if (isa<ConstantPointerNull>(CE1Op0)) {
1148 // If we are indexing from a null pointer, check to see if we have any
1149 // non-zero indices.
1150 for (unsigned i = 1, e = CE1->getNumOperands(); i != e; ++i)
1151 if (!CE1->getOperand(i)->isNullValue())
1152 // Offsetting from null, must not be equal.
1153 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1154 // Only zero indexes from null, must still be zero.
1155 return ICmpInst::ICMP_EQ;
1157 // Otherwise, we can't really say if the first operand is null or not.
1158 } else if (const GlobalValue *CPR2 = dyn_cast<GlobalValue>(V2)) {
1159 if (isa<ConstantPointerNull>(CE1Op0)) {
1160 if (CPR2->hasExternalWeakLinkage())
1161 // Weak linkage GVals could be zero or not. We're comparing it to
1162 // a null pointer, so its less-or-equal
1163 return isSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE;
1165 // If its not weak linkage, the GVal must have a non-zero address
1166 // so the result is less-than
1167 return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1168 } else if (const GlobalValue *CPR1 = dyn_cast<GlobalValue>(CE1Op0)) {
1170 // If this is a getelementptr of the same global, then it must be
1171 // different. Because the types must match, the getelementptr could
1172 // only have at most one index, and because we fold getelementptr's
1173 // with a single zero index, it must be nonzero.
1174 assert(CE1->getNumOperands() == 2 &&
1175 !CE1->getOperand(1)->isNullValue() &&
1176 "Suprising getelementptr!");
1177 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1179 // If they are different globals, we don't know what the value is,
1180 // but they can't be equal.
1181 return ICmpInst::ICMP_NE;
1185 const ConstantExpr *CE2 = cast<ConstantExpr>(V2);
1186 const Constant *CE2Op0 = CE2->getOperand(0);
1188 // There are MANY other foldings that we could perform here. They will
1189 // probably be added on demand, as they seem needed.
1190 switch (CE2->getOpcode()) {
1192 case Instruction::GetElementPtr:
1193 // By far the most common case to handle is when the base pointers are
1194 // obviously to the same or different globals.
1195 if (isa<GlobalValue>(CE1Op0) && isa<GlobalValue>(CE2Op0)) {
1196 if (CE1Op0 != CE2Op0) // Don't know relative ordering, but not equal
1197 return ICmpInst::ICMP_NE;
1198 // Ok, we know that both getelementptr instructions are based on the
1199 // same global. From this, we can precisely determine the relative
1200 // ordering of the resultant pointers.
1203 // Compare all of the operands the GEP's have in common.
1204 gep_type_iterator GTI = gep_type_begin(CE1);
1205 for (;i != CE1->getNumOperands() && i != CE2->getNumOperands();
1207 switch (IdxCompare(CE1->getOperand(i), CE2->getOperand(i),
1208 GTI.getIndexedType())) {
1209 case -1: return isSigned ? ICmpInst::ICMP_SLT:ICmpInst::ICMP_ULT;
1210 case 1: return isSigned ? ICmpInst::ICMP_SGT:ICmpInst::ICMP_UGT;
1211 case -2: return ICmpInst::BAD_ICMP_PREDICATE;
1214 // Ok, we ran out of things they have in common. If any leftovers
1215 // are non-zero then we have a difference, otherwise we are equal.
1216 for (; i < CE1->getNumOperands(); ++i)
1217 if (!CE1->getOperand(i)->isNullValue()) {
1218 if (isa<ConstantInt>(CE1->getOperand(i)))
1219 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1221 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1224 for (; i < CE2->getNumOperands(); ++i)
1225 if (!CE2->getOperand(i)->isNullValue()) {
1226 if (isa<ConstantInt>(CE2->getOperand(i)))
1227 return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1229 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1231 return ICmpInst::ICMP_EQ;
1240 return ICmpInst::BAD_ICMP_PREDICATE;
1243 Constant *llvm::ConstantFoldCompareInstruction(unsigned short pred,
1245 const Constant *C2) {
1246 // Fold FCMP_FALSE/FCMP_TRUE unconditionally.
1247 if (pred == FCmpInst::FCMP_FALSE) {
1248 if (const VectorType *VT = dyn_cast<VectorType>(C1->getType()))
1249 return Constant::getNullValue(VectorType::getInteger(VT));
1251 return ConstantInt::getFalse();
1254 if (pred == FCmpInst::FCMP_TRUE) {
1255 if (const VectorType *VT = dyn_cast<VectorType>(C1->getType()))
1256 return Constant::getAllOnesValue(VectorType::getInteger(VT));
1258 return ConstantInt::getTrue();
1261 // Handle some degenerate cases first
1262 if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
1263 // vicmp/vfcmp -> [vector] undef
1264 if (const VectorType *VTy = dyn_cast<VectorType>(C1->getType()))
1265 return UndefValue::get(VectorType::getInteger(VTy));
1267 // icmp/fcmp -> i1 undef
1268 return UndefValue::get(Type::Int1Ty);
1271 // No compile-time operations on this type yet.
1272 if (C1->getType() == Type::PPC_FP128Ty)
1275 // icmp eq/ne(null,GV) -> false/true
1276 if (C1->isNullValue()) {
1277 if (const GlobalValue *GV = dyn_cast<GlobalValue>(C2))
1278 // Don't try to evaluate aliases. External weak GV can be null.
1279 if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
1280 if (pred == ICmpInst::ICMP_EQ)
1281 return ConstantInt::getFalse();
1282 else if (pred == ICmpInst::ICMP_NE)
1283 return ConstantInt::getTrue();
1285 // icmp eq/ne(GV,null) -> false/true
1286 } else if (C2->isNullValue()) {
1287 if (const GlobalValue *GV = dyn_cast<GlobalValue>(C1))
1288 // Don't try to evaluate aliases. External weak GV can be null.
1289 if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
1290 if (pred == ICmpInst::ICMP_EQ)
1291 return ConstantInt::getFalse();
1292 else if (pred == ICmpInst::ICMP_NE)
1293 return ConstantInt::getTrue();
1297 if (isa<ConstantInt>(C1) && isa<ConstantInt>(C2)) {
1298 APInt V1 = cast<ConstantInt>(C1)->getValue();
1299 APInt V2 = cast<ConstantInt>(C2)->getValue();
1301 default: assert(0 && "Invalid ICmp Predicate"); return 0;
1302 case ICmpInst::ICMP_EQ: return ConstantInt::get(Type::Int1Ty, V1 == V2);
1303 case ICmpInst::ICMP_NE: return ConstantInt::get(Type::Int1Ty, V1 != V2);
1304 case ICmpInst::ICMP_SLT:return ConstantInt::get(Type::Int1Ty, V1.slt(V2));
1305 case ICmpInst::ICMP_SGT:return ConstantInt::get(Type::Int1Ty, V1.sgt(V2));
1306 case ICmpInst::ICMP_SLE:return ConstantInt::get(Type::Int1Ty, V1.sle(V2));
1307 case ICmpInst::ICMP_SGE:return ConstantInt::get(Type::Int1Ty, V1.sge(V2));
1308 case ICmpInst::ICMP_ULT:return ConstantInt::get(Type::Int1Ty, V1.ult(V2));
1309 case ICmpInst::ICMP_UGT:return ConstantInt::get(Type::Int1Ty, V1.ugt(V2));
1310 case ICmpInst::ICMP_ULE:return ConstantInt::get(Type::Int1Ty, V1.ule(V2));
1311 case ICmpInst::ICMP_UGE:return ConstantInt::get(Type::Int1Ty, V1.uge(V2));
1313 } else if (isa<ConstantFP>(C1) && isa<ConstantFP>(C2)) {
1314 APFloat C1V = cast<ConstantFP>(C1)->getValueAPF();
1315 APFloat C2V = cast<ConstantFP>(C2)->getValueAPF();
1316 APFloat::cmpResult R = C1V.compare(C2V);
1318 default: assert(0 && "Invalid FCmp Predicate"); return 0;
1319 case FCmpInst::FCMP_FALSE: return ConstantInt::getFalse();
1320 case FCmpInst::FCMP_TRUE: return ConstantInt::getTrue();
1321 case FCmpInst::FCMP_UNO:
1322 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpUnordered);
1323 case FCmpInst::FCMP_ORD:
1324 return ConstantInt::get(Type::Int1Ty, R!=APFloat::cmpUnordered);
1325 case FCmpInst::FCMP_UEQ:
1326 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpUnordered ||
1327 R==APFloat::cmpEqual);
1328 case FCmpInst::FCMP_OEQ:
1329 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpEqual);
1330 case FCmpInst::FCMP_UNE:
1331 return ConstantInt::get(Type::Int1Ty, R!=APFloat::cmpEqual);
1332 case FCmpInst::FCMP_ONE:
1333 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpLessThan ||
1334 R==APFloat::cmpGreaterThan);
1335 case FCmpInst::FCMP_ULT:
1336 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpUnordered ||
1337 R==APFloat::cmpLessThan);
1338 case FCmpInst::FCMP_OLT:
1339 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpLessThan);
1340 case FCmpInst::FCMP_UGT:
1341 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpUnordered ||
1342 R==APFloat::cmpGreaterThan);
1343 case FCmpInst::FCMP_OGT:
1344 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpGreaterThan);
1345 case FCmpInst::FCMP_ULE:
1346 return ConstantInt::get(Type::Int1Ty, R!=APFloat::cmpGreaterThan);
1347 case FCmpInst::FCMP_OLE:
1348 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpLessThan ||
1349 R==APFloat::cmpEqual);
1350 case FCmpInst::FCMP_UGE:
1351 return ConstantInt::get(Type::Int1Ty, R!=APFloat::cmpLessThan);
1352 case FCmpInst::FCMP_OGE:
1353 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpGreaterThan ||
1354 R==APFloat::cmpEqual);
1356 } else if (isa<VectorType>(C1->getType())) {
1357 SmallVector<Constant*, 16> C1Elts, C2Elts;
1358 C1->getVectorElements(C1Elts);
1359 C2->getVectorElements(C2Elts);
1361 // If we can constant fold the comparison of each element, constant fold
1362 // the whole vector comparison.
1363 SmallVector<Constant*, 4> ResElts;
1364 const Type *InEltTy = C1Elts[0]->getType();
1365 bool isFP = InEltTy->isFloatingPoint();
1366 const Type *ResEltTy = InEltTy;
1368 ResEltTy = IntegerType::get(InEltTy->getPrimitiveSizeInBits());
1370 for (unsigned i = 0, e = C1Elts.size(); i != e; ++i) {
1371 // Compare the elements, producing an i1 result or constant expr.
1374 C = ConstantExpr::getFCmp(pred, C1Elts[i], C2Elts[i]);
1376 C = ConstantExpr::getICmp(pred, C1Elts[i], C2Elts[i]);
1378 // If it is a bool or undef result, convert to the dest type.
1379 if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
1381 ResElts.push_back(Constant::getNullValue(ResEltTy));
1383 ResElts.push_back(Constant::getAllOnesValue(ResEltTy));
1384 } else if (isa<UndefValue>(C)) {
1385 ResElts.push_back(UndefValue::get(ResEltTy));
1391 if (ResElts.size() == C1Elts.size())
1392 return ConstantVector::get(&ResElts[0], ResElts.size());
1395 if (C1->getType()->isFloatingPoint()) {
1396 int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
1397 switch (evaluateFCmpRelation(C1, C2)) {
1398 default: assert(0 && "Unknown relation!");
1399 case FCmpInst::FCMP_UNO:
1400 case FCmpInst::FCMP_ORD:
1401 case FCmpInst::FCMP_UEQ:
1402 case FCmpInst::FCMP_UNE:
1403 case FCmpInst::FCMP_ULT:
1404 case FCmpInst::FCMP_UGT:
1405 case FCmpInst::FCMP_ULE:
1406 case FCmpInst::FCMP_UGE:
1407 case FCmpInst::FCMP_TRUE:
1408 case FCmpInst::FCMP_FALSE:
1409 case FCmpInst::BAD_FCMP_PREDICATE:
1410 break; // Couldn't determine anything about these constants.
1411 case FCmpInst::FCMP_OEQ: // We know that C1 == C2
1412 Result = (pred == FCmpInst::FCMP_UEQ || pred == FCmpInst::FCMP_OEQ ||
1413 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE ||
1414 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
1416 case FCmpInst::FCMP_OLT: // We know that C1 < C2
1417 Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
1418 pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT ||
1419 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE);
1421 case FCmpInst::FCMP_OGT: // We know that C1 > C2
1422 Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
1423 pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT ||
1424 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
1426 case FCmpInst::FCMP_OLE: // We know that C1 <= C2
1427 // We can only partially decide this relation.
1428 if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
1430 else if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
1433 case FCmpInst::FCMP_OGE: // We known that C1 >= C2
1434 // We can only partially decide this relation.
1435 if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
1437 else if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
1440 case ICmpInst::ICMP_NE: // We know that C1 != C2
1441 // We can only partially decide this relation.
1442 if (pred == FCmpInst::FCMP_OEQ || pred == FCmpInst::FCMP_UEQ)
1444 else if (pred == FCmpInst::FCMP_ONE || pred == FCmpInst::FCMP_UNE)
1449 // If we evaluated the result, return it now.
1451 if (const VectorType *VT = dyn_cast<VectorType>(C1->getType())) {
1453 return Constant::getNullValue(VectorType::getInteger(VT));
1455 return Constant::getAllOnesValue(VectorType::getInteger(VT));
1457 return ConstantInt::get(Type::Int1Ty, Result);
1461 // Evaluate the relation between the two constants, per the predicate.
1462 int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
1463 switch (evaluateICmpRelation(C1, C2, CmpInst::isSigned(pred))) {
1464 default: assert(0 && "Unknown relational!");
1465 case ICmpInst::BAD_ICMP_PREDICATE:
1466 break; // Couldn't determine anything about these constants.
1467 case ICmpInst::ICMP_EQ: // We know the constants are equal!
1468 // If we know the constants are equal, we can decide the result of this
1469 // computation precisely.
1470 Result = (pred == ICmpInst::ICMP_EQ ||
1471 pred == ICmpInst::ICMP_ULE ||
1472 pred == ICmpInst::ICMP_SLE ||
1473 pred == ICmpInst::ICMP_UGE ||
1474 pred == ICmpInst::ICMP_SGE);
1476 case ICmpInst::ICMP_ULT:
1477 // If we know that C1 < C2, we can decide the result of this computation
1479 Result = (pred == ICmpInst::ICMP_ULT ||
1480 pred == ICmpInst::ICMP_NE ||
1481 pred == ICmpInst::ICMP_ULE);
1483 case ICmpInst::ICMP_SLT:
1484 // If we know that C1 < C2, we can decide the result of this computation
1486 Result = (pred == ICmpInst::ICMP_SLT ||
1487 pred == ICmpInst::ICMP_NE ||
1488 pred == ICmpInst::ICMP_SLE);
1490 case ICmpInst::ICMP_UGT:
1491 // If we know that C1 > C2, we can decide the result of this computation
1493 Result = (pred == ICmpInst::ICMP_UGT ||
1494 pred == ICmpInst::ICMP_NE ||
1495 pred == ICmpInst::ICMP_UGE);
1497 case ICmpInst::ICMP_SGT:
1498 // If we know that C1 > C2, we can decide the result of this computation
1500 Result = (pred == ICmpInst::ICMP_SGT ||
1501 pred == ICmpInst::ICMP_NE ||
1502 pred == ICmpInst::ICMP_SGE);
1504 case ICmpInst::ICMP_ULE:
1505 // If we know that C1 <= C2, we can only partially decide this relation.
1506 if (pred == ICmpInst::ICMP_UGT) Result = 0;
1507 if (pred == ICmpInst::ICMP_ULT) Result = 1;
1509 case ICmpInst::ICMP_SLE:
1510 // If we know that C1 <= C2, we can only partially decide this relation.
1511 if (pred == ICmpInst::ICMP_SGT) Result = 0;
1512 if (pred == ICmpInst::ICMP_SLT) Result = 1;
1515 case ICmpInst::ICMP_UGE:
1516 // If we know that C1 >= C2, we can only partially decide this relation.
1517 if (pred == ICmpInst::ICMP_ULT) Result = 0;
1518 if (pred == ICmpInst::ICMP_UGT) Result = 1;
1520 case ICmpInst::ICMP_SGE:
1521 // If we know that C1 >= C2, we can only partially decide this relation.
1522 if (pred == ICmpInst::ICMP_SLT) Result = 0;
1523 if (pred == ICmpInst::ICMP_SGT) Result = 1;
1526 case ICmpInst::ICMP_NE:
1527 // If we know that C1 != C2, we can only partially decide this relation.
1528 if (pred == ICmpInst::ICMP_EQ) Result = 0;
1529 if (pred == ICmpInst::ICMP_NE) Result = 1;
1533 // If we evaluated the result, return it now.
1535 if (const VectorType *VT = dyn_cast<VectorType>(C1->getType())) {
1537 return Constant::getNullValue(VT);
1539 return Constant::getAllOnesValue(VT);
1541 return ConstantInt::get(Type::Int1Ty, Result);
1544 if (!isa<ConstantExpr>(C1) && isa<ConstantExpr>(C2)) {
1545 // If C2 is a constant expr and C1 isn't, flop them around and fold the
1546 // other way if possible.
1548 case ICmpInst::ICMP_EQ:
1549 case ICmpInst::ICMP_NE:
1550 // No change of predicate required.
1551 return ConstantFoldCompareInstruction(pred, C2, C1);
1553 case ICmpInst::ICMP_ULT:
1554 case ICmpInst::ICMP_SLT:
1555 case ICmpInst::ICMP_UGT:
1556 case ICmpInst::ICMP_SGT:
1557 case ICmpInst::ICMP_ULE:
1558 case ICmpInst::ICMP_SLE:
1559 case ICmpInst::ICMP_UGE:
1560 case ICmpInst::ICMP_SGE:
1561 // Change the predicate as necessary to swap the operands.
1562 pred = ICmpInst::getSwappedPredicate((ICmpInst::Predicate)pred);
1563 return ConstantFoldCompareInstruction(pred, C2, C1);
1565 default: // These predicates cannot be flopped around.
1573 Constant *llvm::ConstantFoldGetElementPtr(const Constant *C,
1574 Constant* const *Idxs,
1577 (NumIdx == 1 && Idxs[0]->isNullValue()))
1578 return const_cast<Constant*>(C);
1580 if (isa<UndefValue>(C)) {
1581 const PointerType *Ptr = cast<PointerType>(C->getType());
1582 const Type *Ty = GetElementPtrInst::getIndexedType(Ptr,
1584 (Value **)Idxs+NumIdx);
1585 assert(Ty != 0 && "Invalid indices for GEP!");
1586 return UndefValue::get(PointerType::get(Ty, Ptr->getAddressSpace()));
1589 Constant *Idx0 = Idxs[0];
1590 if (C->isNullValue()) {
1592 for (unsigned i = 0, e = NumIdx; i != e; ++i)
1593 if (!Idxs[i]->isNullValue()) {
1598 const PointerType *Ptr = cast<PointerType>(C->getType());
1599 const Type *Ty = GetElementPtrInst::getIndexedType(Ptr,
1601 (Value**)Idxs+NumIdx);
1602 assert(Ty != 0 && "Invalid indices for GEP!");
1604 ConstantPointerNull::get(PointerType::get(Ty,Ptr->getAddressSpace()));
1608 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(const_cast<Constant*>(C))) {
1609 // Combine Indices - If the source pointer to this getelementptr instruction
1610 // is a getelementptr instruction, combine the indices of the two
1611 // getelementptr instructions into a single instruction.
1613 if (CE->getOpcode() == Instruction::GetElementPtr) {
1614 const Type *LastTy = 0;
1615 for (gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
1619 if ((LastTy && isa<ArrayType>(LastTy)) || Idx0->isNullValue()) {
1620 SmallVector<Value*, 16> NewIndices;
1621 NewIndices.reserve(NumIdx + CE->getNumOperands());
1622 for (unsigned i = 1, e = CE->getNumOperands()-1; i != e; ++i)
1623 NewIndices.push_back(CE->getOperand(i));
1625 // Add the last index of the source with the first index of the new GEP.
1626 // Make sure to handle the case when they are actually different types.
1627 Constant *Combined = CE->getOperand(CE->getNumOperands()-1);
1628 // Otherwise it must be an array.
1629 if (!Idx0->isNullValue()) {
1630 const Type *IdxTy = Combined->getType();
1631 if (IdxTy != Idx0->getType()) {
1632 Constant *C1 = ConstantExpr::getSExtOrBitCast(Idx0, Type::Int64Ty);
1633 Constant *C2 = ConstantExpr::getSExtOrBitCast(Combined,
1635 Combined = ConstantExpr::get(Instruction::Add, C1, C2);
1638 ConstantExpr::get(Instruction::Add, Idx0, Combined);
1642 NewIndices.push_back(Combined);
1643 NewIndices.insert(NewIndices.end(), Idxs+1, Idxs+NumIdx);
1644 return ConstantExpr::getGetElementPtr(CE->getOperand(0), &NewIndices[0],
1649 // Implement folding of:
1650 // int* getelementptr ([2 x int]* cast ([3 x int]* %X to [2 x int]*),
1652 // To: int* getelementptr ([3 x int]* %X, long 0, long 0)
1654 if (CE->isCast() && NumIdx > 1 && Idx0->isNullValue()) {
1655 if (const PointerType *SPT =
1656 dyn_cast<PointerType>(CE->getOperand(0)->getType()))
1657 if (const ArrayType *SAT = dyn_cast<ArrayType>(SPT->getElementType()))
1658 if (const ArrayType *CAT =
1659 dyn_cast<ArrayType>(cast<PointerType>(C->getType())->getElementType()))
1660 if (CAT->getElementType() == SAT->getElementType())
1661 return ConstantExpr::getGetElementPtr(
1662 (Constant*)CE->getOperand(0), Idxs, NumIdx);
1665 // Fold: getelementptr (i8* inttoptr (i64 1 to i8*), i32 -1)
1666 // Into: inttoptr (i64 0 to i8*)
1667 // This happens with pointers to member functions in C++.
1668 if (CE->getOpcode() == Instruction::IntToPtr && NumIdx == 1 &&
1669 isa<ConstantInt>(CE->getOperand(0)) && isa<ConstantInt>(Idxs[0]) &&
1670 cast<PointerType>(CE->getType())->getElementType() == Type::Int8Ty) {
1671 Constant *Base = CE->getOperand(0);
1672 Constant *Offset = Idxs[0];
1674 // Convert the smaller integer to the larger type.
1675 if (Offset->getType()->getPrimitiveSizeInBits() <
1676 Base->getType()->getPrimitiveSizeInBits())
1677 Offset = ConstantExpr::getSExt(Offset, Base->getType());
1678 else if (Base->getType()->getPrimitiveSizeInBits() <
1679 Offset->getType()->getPrimitiveSizeInBits())
1680 Base = ConstantExpr::getZExt(Base, Offset->getType());
1682 Base = ConstantExpr::getAdd(Base, Offset);
1683 return ConstantExpr::getIntToPtr(Base, CE->getType());