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 assert((DestTy == Type::DoubleTy || DestTy == Type::FloatTy) &&
160 return ConstantFP::get(APFloat(CI->getValue()));
162 // Otherwise, can't fold this (vector?)
166 // Handle ConstantFP input.
167 if (const ConstantFP *FP = dyn_cast<ConstantFP>(V)) {
169 if (DestTy == Type::Int32Ty) {
170 return ConstantInt::get(FP->getValueAPF().bitcastToAPInt());
172 assert(DestTy == Type::Int64Ty && "only support f32/f64 for now!");
173 return ConstantInt::get(FP->getValueAPF().bitcastToAPInt());
180 Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
181 const Type *DestTy) {
182 if (isa<UndefValue>(V)) {
183 // zext(undef) = 0, because the top bits will be zero.
184 // sext(undef) = 0, because the top bits will all be the same.
185 // [us]itofp(undef) = 0, because the result value is bounded.
186 if (opc == Instruction::ZExt || opc == Instruction::SExt ||
187 opc == Instruction::UIToFP || opc == Instruction::SIToFP)
188 return Constant::getNullValue(DestTy);
189 return UndefValue::get(DestTy);
191 // No compile-time operations on this type yet.
192 if (V->getType() == Type::PPC_FP128Ty || DestTy == Type::PPC_FP128Ty)
195 // If the cast operand is a constant expression, there's a few things we can
196 // do to try to simplify it.
197 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
199 // Try hard to fold cast of cast because they are often eliminable.
200 if (unsigned newOpc = foldConstantCastPair(opc, CE, DestTy))
201 return ConstantExpr::getCast(newOpc, CE->getOperand(0), DestTy);
202 } else if (CE->getOpcode() == Instruction::GetElementPtr) {
203 // If all of the indexes in the GEP are null values, there is no pointer
204 // adjustment going on. We might as well cast the source pointer.
205 bool isAllNull = true;
206 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
207 if (!CE->getOperand(i)->isNullValue()) {
212 // This is casting one pointer type to another, always BitCast
213 return ConstantExpr::getPointerCast(CE->getOperand(0), DestTy);
217 // We actually have to do a cast now. Perform the cast according to the
220 case Instruction::FPTrunc:
221 case Instruction::FPExt:
222 if (const ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
224 APFloat Val = FPC->getValueAPF();
225 Val.convert(DestTy == Type::FloatTy ? APFloat::IEEEsingle :
226 DestTy == Type::DoubleTy ? APFloat::IEEEdouble :
227 DestTy == Type::X86_FP80Ty ? APFloat::x87DoubleExtended :
228 DestTy == Type::FP128Ty ? APFloat::IEEEquad :
230 APFloat::rmNearestTiesToEven, &ignored);
231 return ConstantFP::get(Val);
233 return 0; // Can't fold.
234 case Instruction::FPToUI:
235 case Instruction::FPToSI:
236 if (const ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
237 const APFloat &V = FPC->getValueAPF();
240 uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
241 (void) V.convertToInteger(x, DestBitWidth, opc==Instruction::FPToSI,
242 APFloat::rmTowardZero, &ignored);
243 APInt Val(DestBitWidth, 2, x);
244 return ConstantInt::get(Val);
246 if (const ConstantVector *CV = dyn_cast<ConstantVector>(V)) {
247 std::vector<Constant*> res;
248 const VectorType *DestVecTy = cast<VectorType>(DestTy);
249 const Type *DstEltTy = DestVecTy->getElementType();
250 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
251 res.push_back(ConstantExpr::getCast(opc, CV->getOperand(i), DstEltTy));
252 return ConstantVector::get(DestVecTy, res);
254 return 0; // Can't fold.
255 case Instruction::IntToPtr: //always treated as unsigned
256 if (V->isNullValue()) // Is it an integral null value?
257 return ConstantPointerNull::get(cast<PointerType>(DestTy));
258 return 0; // Other pointer types cannot be casted
259 case Instruction::PtrToInt: // always treated as unsigned
260 if (V->isNullValue()) // is it a null pointer value?
261 return ConstantInt::get(DestTy, 0);
262 return 0; // Other pointer types cannot be casted
263 case Instruction::UIToFP:
264 case Instruction::SIToFP:
265 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
266 APInt api = CI->getValue();
267 const uint64_t zero[] = {0, 0};
268 APFloat apf = APFloat(APInt(DestTy->getPrimitiveSizeInBits(),
270 (void)apf.convertFromAPInt(api,
271 opc==Instruction::SIToFP,
272 APFloat::rmNearestTiesToEven);
273 return ConstantFP::get(apf);
275 if (const ConstantVector *CV = dyn_cast<ConstantVector>(V)) {
276 std::vector<Constant*> res;
277 const VectorType *DestVecTy = cast<VectorType>(DestTy);
278 const Type *DstEltTy = DestVecTy->getElementType();
279 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
280 res.push_back(ConstantExpr::getCast(opc, CV->getOperand(i), DstEltTy));
281 return ConstantVector::get(DestVecTy, res);
284 case Instruction::ZExt:
285 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
286 uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
287 APInt Result(CI->getValue());
288 Result.zext(BitWidth);
289 return ConstantInt::get(Result);
292 case Instruction::SExt:
293 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
294 uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
295 APInt Result(CI->getValue());
296 Result.sext(BitWidth);
297 return ConstantInt::get(Result);
300 case Instruction::Trunc:
301 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
302 uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
303 APInt Result(CI->getValue());
304 Result.trunc(BitWidth);
305 return ConstantInt::get(Result);
308 case Instruction::BitCast:
309 return FoldBitCast(const_cast<Constant*>(V), DestTy);
311 assert(!"Invalid CE CastInst opcode");
315 assert(0 && "Failed to cast constant expression");
319 Constant *llvm::ConstantFoldSelectInstruction(const Constant *Cond,
321 const Constant *V2) {
322 if (const ConstantInt *CB = dyn_cast<ConstantInt>(Cond))
323 return const_cast<Constant*>(CB->getZExtValue() ? V1 : V2);
325 if (isa<UndefValue>(V1)) return const_cast<Constant*>(V2);
326 if (isa<UndefValue>(V2)) return const_cast<Constant*>(V1);
327 if (isa<UndefValue>(Cond)) return const_cast<Constant*>(V1);
328 if (V1 == V2) return const_cast<Constant*>(V1);
332 Constant *llvm::ConstantFoldExtractElementInstruction(const Constant *Val,
333 const Constant *Idx) {
334 if (isa<UndefValue>(Val)) // ee(undef, x) -> undef
335 return UndefValue::get(cast<VectorType>(Val->getType())->getElementType());
336 if (Val->isNullValue()) // ee(zero, x) -> zero
337 return Constant::getNullValue(
338 cast<VectorType>(Val->getType())->getElementType());
340 if (const ConstantVector *CVal = dyn_cast<ConstantVector>(Val)) {
341 if (const ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx)) {
342 return CVal->getOperand(CIdx->getZExtValue());
343 } else if (isa<UndefValue>(Idx)) {
344 // ee({w,x,y,z}, undef) -> w (an arbitrary value).
345 return CVal->getOperand(0);
351 Constant *llvm::ConstantFoldInsertElementInstruction(const Constant *Val,
353 const Constant *Idx) {
354 const ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx);
356 APInt idxVal = CIdx->getValue();
357 if (isa<UndefValue>(Val)) {
358 // Insertion of scalar constant into vector undef
359 // Optimize away insertion of undef
360 if (isa<UndefValue>(Elt))
361 return const_cast<Constant*>(Val);
362 // Otherwise break the aggregate undef into multiple undefs and do
365 cast<VectorType>(Val->getType())->getNumElements();
366 std::vector<Constant*> Ops;
368 for (unsigned i = 0; i < numOps; ++i) {
370 (idxVal == i) ? Elt : UndefValue::get(Elt->getType());
371 Ops.push_back(const_cast<Constant*>(Op));
373 return ConstantVector::get(Ops);
375 if (isa<ConstantAggregateZero>(Val)) {
376 // Insertion of scalar constant into vector aggregate zero
377 // Optimize away insertion of zero
378 if (Elt->isNullValue())
379 return const_cast<Constant*>(Val);
380 // Otherwise break the aggregate zero into multiple zeros and do
383 cast<VectorType>(Val->getType())->getNumElements();
384 std::vector<Constant*> Ops;
386 for (unsigned i = 0; i < numOps; ++i) {
388 (idxVal == i) ? Elt : Constant::getNullValue(Elt->getType());
389 Ops.push_back(const_cast<Constant*>(Op));
391 return ConstantVector::get(Ops);
393 if (const ConstantVector *CVal = dyn_cast<ConstantVector>(Val)) {
394 // Insertion of scalar constant into vector constant
395 std::vector<Constant*> Ops;
396 Ops.reserve(CVal->getNumOperands());
397 for (unsigned i = 0; i < CVal->getNumOperands(); ++i) {
399 (idxVal == i) ? Elt : cast<Constant>(CVal->getOperand(i));
400 Ops.push_back(const_cast<Constant*>(Op));
402 return ConstantVector::get(Ops);
408 /// GetVectorElement - If C is a ConstantVector, ConstantAggregateZero or Undef
409 /// return the specified element value. Otherwise return null.
410 static Constant *GetVectorElement(const Constant *C, unsigned EltNo) {
411 if (const ConstantVector *CV = dyn_cast<ConstantVector>(C))
412 return CV->getOperand(EltNo);
414 const Type *EltTy = cast<VectorType>(C->getType())->getElementType();
415 if (isa<ConstantAggregateZero>(C))
416 return Constant::getNullValue(EltTy);
417 if (isa<UndefValue>(C))
418 return UndefValue::get(EltTy);
422 Constant *llvm::ConstantFoldShuffleVectorInstruction(const Constant *V1,
424 const Constant *Mask) {
425 // Undefined shuffle mask -> undefined value.
426 if (isa<UndefValue>(Mask)) return UndefValue::get(V1->getType());
428 unsigned NumElts = cast<VectorType>(V1->getType())->getNumElements();
429 const Type *EltTy = cast<VectorType>(V1->getType())->getElementType();
431 // Loop over the shuffle mask, evaluating each element.
432 SmallVector<Constant*, 32> Result;
433 for (unsigned i = 0; i != NumElts; ++i) {
434 Constant *InElt = GetVectorElement(Mask, i);
435 if (InElt == 0) return 0;
437 if (isa<UndefValue>(InElt))
438 InElt = UndefValue::get(EltTy);
439 else if (ConstantInt *CI = dyn_cast<ConstantInt>(InElt)) {
440 unsigned Elt = CI->getZExtValue();
441 if (Elt >= NumElts*2)
442 InElt = UndefValue::get(EltTy);
443 else if (Elt >= NumElts)
444 InElt = GetVectorElement(V2, Elt-NumElts);
446 InElt = GetVectorElement(V1, Elt);
447 if (InElt == 0) return 0;
452 Result.push_back(InElt);
455 return ConstantVector::get(&Result[0], Result.size());
458 Constant *llvm::ConstantFoldExtractValueInstruction(const Constant *Agg,
459 const unsigned *Idxs,
461 // Base case: no indices, so return the entire value.
463 return const_cast<Constant *>(Agg);
465 if (isa<UndefValue>(Agg)) // ev(undef, x) -> undef
466 return UndefValue::get(ExtractValueInst::getIndexedType(Agg->getType(),
470 if (isa<ConstantAggregateZero>(Agg)) // ev(0, x) -> 0
472 Constant::getNullValue(ExtractValueInst::getIndexedType(Agg->getType(),
476 // Otherwise recurse.
477 return ConstantFoldExtractValueInstruction(Agg->getOperand(*Idxs),
481 Constant *llvm::ConstantFoldInsertValueInstruction(const Constant *Agg,
483 const unsigned *Idxs,
485 // Base case: no indices, so replace the entire value.
487 return const_cast<Constant *>(Val);
489 if (isa<UndefValue>(Agg)) {
490 // Insertion of constant into aggregate undef
491 // Optimize away insertion of undef
492 if (isa<UndefValue>(Val))
493 return const_cast<Constant*>(Agg);
494 // Otherwise break the aggregate undef into multiple undefs and do
496 const CompositeType *AggTy = cast<CompositeType>(Agg->getType());
498 if (const ArrayType *AR = dyn_cast<ArrayType>(AggTy))
499 numOps = AR->getNumElements();
501 numOps = cast<StructType>(AggTy)->getNumElements();
502 std::vector<Constant*> Ops(numOps);
503 for (unsigned i = 0; i < numOps; ++i) {
504 const Type *MemberTy = AggTy->getTypeAtIndex(i);
507 ConstantFoldInsertValueInstruction(UndefValue::get(MemberTy),
508 Val, Idxs+1, NumIdx-1) :
509 UndefValue::get(MemberTy);
510 Ops[i] = const_cast<Constant*>(Op);
512 if (isa<StructType>(AggTy))
513 return ConstantStruct::get(Ops);
515 return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
517 if (isa<ConstantAggregateZero>(Agg)) {
518 // Insertion of constant into aggregate zero
519 // Optimize away insertion of zero
520 if (Val->isNullValue())
521 return const_cast<Constant*>(Agg);
522 // Otherwise break the aggregate zero into multiple zeros and do
524 const CompositeType *AggTy = cast<CompositeType>(Agg->getType());
526 if (const ArrayType *AR = dyn_cast<ArrayType>(AggTy))
527 numOps = AR->getNumElements();
529 numOps = cast<StructType>(AggTy)->getNumElements();
530 std::vector<Constant*> Ops(numOps);
531 for (unsigned i = 0; i < numOps; ++i) {
532 const Type *MemberTy = AggTy->getTypeAtIndex(i);
535 ConstantFoldInsertValueInstruction(Constant::getNullValue(MemberTy),
536 Val, Idxs+1, NumIdx-1) :
537 Constant::getNullValue(MemberTy);
538 Ops[i] = const_cast<Constant*>(Op);
540 if (isa<StructType>(AggTy))
541 return ConstantStruct::get(Ops);
543 return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
545 if (isa<ConstantStruct>(Agg) || isa<ConstantArray>(Agg)) {
546 // Insertion of constant into aggregate constant
547 std::vector<Constant*> Ops(Agg->getNumOperands());
548 for (unsigned i = 0; i < Agg->getNumOperands(); ++i) {
551 ConstantFoldInsertValueInstruction(Agg->getOperand(i),
552 Val, Idxs+1, NumIdx-1) :
554 Ops[i] = const_cast<Constant*>(Op);
557 if (isa<StructType>(Agg->getType()))
558 C = ConstantStruct::get(Ops);
560 C = ConstantArray::get(cast<ArrayType>(Agg->getType()), Ops);
567 /// EvalVectorOp - Given two vector constants and a function pointer, apply the
568 /// function pointer to each element pair, producing a new ConstantVector
569 /// constant. Either or both of V1 and V2 may be NULL, meaning a
570 /// ConstantAggregateZero operand.
571 static Constant *EvalVectorOp(const ConstantVector *V1,
572 const ConstantVector *V2,
573 const VectorType *VTy,
574 Constant *(*FP)(Constant*, Constant*)) {
575 std::vector<Constant*> Res;
576 const Type *EltTy = VTy->getElementType();
577 for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
578 const Constant *C1 = V1 ? V1->getOperand(i) : Constant::getNullValue(EltTy);
579 const Constant *C2 = V2 ? V2->getOperand(i) : Constant::getNullValue(EltTy);
580 Res.push_back(FP(const_cast<Constant*>(C1),
581 const_cast<Constant*>(C2)));
583 return ConstantVector::get(Res);
586 Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
588 const Constant *C2) {
589 // No compile-time operations on this type yet.
590 if (C1->getType() == Type::PPC_FP128Ty)
593 // Handle UndefValue up front
594 if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
596 case Instruction::Xor:
597 if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
598 // Handle undef ^ undef -> 0 special case. This is a common
600 return Constant::getNullValue(C1->getType());
602 case Instruction::Add:
603 case Instruction::Sub:
604 return UndefValue::get(C1->getType());
605 case Instruction::Mul:
606 case Instruction::And:
607 return Constant::getNullValue(C1->getType());
608 case Instruction::UDiv:
609 case Instruction::SDiv:
610 case Instruction::FDiv:
611 case Instruction::URem:
612 case Instruction::SRem:
613 case Instruction::FRem:
614 if (!isa<UndefValue>(C2)) // undef / X -> 0
615 return Constant::getNullValue(C1->getType());
616 return const_cast<Constant*>(C2); // X / undef -> undef
617 case Instruction::Or: // X | undef -> -1
618 if (const VectorType *PTy = dyn_cast<VectorType>(C1->getType()))
619 return ConstantVector::getAllOnesValue(PTy);
620 return ConstantInt::getAllOnesValue(C1->getType());
621 case Instruction::LShr:
622 if (isa<UndefValue>(C2) && isa<UndefValue>(C1))
623 return const_cast<Constant*>(C1); // undef lshr undef -> undef
624 return Constant::getNullValue(C1->getType()); // X lshr undef -> 0
626 case Instruction::AShr:
627 if (!isa<UndefValue>(C2))
628 return const_cast<Constant*>(C1); // undef ashr X --> undef
629 else if (isa<UndefValue>(C1))
630 return const_cast<Constant*>(C1); // undef ashr undef -> undef
632 return const_cast<Constant*>(C1); // X ashr undef --> X
633 case Instruction::Shl:
634 // undef << X -> 0 or X << undef -> 0
635 return Constant::getNullValue(C1->getType());
639 // Handle simplifications of the RHS when a constant int.
640 if (const ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
642 case Instruction::Add:
643 if (CI2->equalsInt(0)) return const_cast<Constant*>(C1); // X + 0 == X
645 case Instruction::Sub:
646 if (CI2->equalsInt(0)) return const_cast<Constant*>(C1); // X - 0 == X
648 case Instruction::Mul:
649 if (CI2->equalsInt(0)) return const_cast<Constant*>(C2); // X * 0 == 0
650 if (CI2->equalsInt(1))
651 return const_cast<Constant*>(C1); // X * 1 == X
653 case Instruction::UDiv:
654 case Instruction::SDiv:
655 if (CI2->equalsInt(1))
656 return const_cast<Constant*>(C1); // X / 1 == X
658 case Instruction::URem:
659 case Instruction::SRem:
660 if (CI2->equalsInt(1))
661 return Constant::getNullValue(CI2->getType()); // X % 1 == 0
663 case Instruction::And:
664 if (CI2->isZero()) return const_cast<Constant*>(C2); // X & 0 == 0
665 if (CI2->isAllOnesValue())
666 return const_cast<Constant*>(C1); // X & -1 == X
668 if (const ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
669 // (zext i32 to i64) & 4294967295 -> (zext i32 to i64)
670 if (CE1->getOpcode() == Instruction::ZExt) {
671 unsigned DstWidth = CI2->getType()->getBitWidth();
673 CE1->getOperand(0)->getType()->getPrimitiveSizeInBits();
674 APInt PossiblySetBits(APInt::getLowBitsSet(DstWidth, SrcWidth));
675 if ((PossiblySetBits & CI2->getValue()) == PossiblySetBits)
676 return const_cast<Constant*>(C1);
679 // If and'ing the address of a global with a constant, fold it.
680 if (CE1->getOpcode() == Instruction::PtrToInt &&
681 isa<GlobalValue>(CE1->getOperand(0))) {
682 GlobalValue *GV = cast<GlobalValue>(CE1->getOperand(0));
684 // Functions are at least 4-byte aligned.
685 unsigned GVAlign = GV->getAlignment();
686 if (isa<Function>(GV))
687 GVAlign = std::max(GVAlign, 4U);
690 unsigned DstWidth = CI2->getType()->getBitWidth();
691 unsigned SrcWidth = std::min(DstWidth, Log2_32(GVAlign));
692 APInt BitsNotSet(APInt::getLowBitsSet(DstWidth, SrcWidth));
694 // If checking bits we know are clear, return zero.
695 if ((CI2->getValue() & BitsNotSet) == CI2->getValue())
696 return Constant::getNullValue(CI2->getType());
701 case Instruction::Or:
702 if (CI2->equalsInt(0)) return const_cast<Constant*>(C1); // X | 0 == X
703 if (CI2->isAllOnesValue())
704 return const_cast<Constant*>(C2); // X | -1 == -1
706 case Instruction::Xor:
707 if (CI2->equalsInt(0)) return const_cast<Constant*>(C1); // X ^ 0 == X
709 case Instruction::AShr:
710 // ashr (zext C to Ty), C2 -> lshr (zext C, CSA), C2
711 if (const ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1))
712 if (CE1->getOpcode() == Instruction::ZExt) // Top bits known zero.
713 return ConstantExpr::getLShr(const_cast<Constant*>(C1),
714 const_cast<Constant*>(C2));
719 // At this point we know neither constant is an UndefValue.
720 if (const ConstantInt *CI1 = dyn_cast<ConstantInt>(C1)) {
721 if (const ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
722 using namespace APIntOps;
723 const APInt &C1V = CI1->getValue();
724 const APInt &C2V = CI2->getValue();
728 case Instruction::Add:
729 return ConstantInt::get(C1V + C2V);
730 case Instruction::Sub:
731 return ConstantInt::get(C1V - C2V);
732 case Instruction::Mul:
733 return ConstantInt::get(C1V * C2V);
734 case Instruction::UDiv:
735 if (CI2->isNullValue())
736 return 0; // X / 0 -> can't fold
737 return ConstantInt::get(C1V.udiv(C2V));
738 case Instruction::SDiv:
739 if (CI2->isNullValue())
740 return 0; // X / 0 -> can't fold
741 if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
742 return 0; // MIN_INT / -1 -> overflow
743 return ConstantInt::get(C1V.sdiv(C2V));
744 case Instruction::URem:
745 if (C2->isNullValue())
746 return 0; // X / 0 -> can't fold
747 return ConstantInt::get(C1V.urem(C2V));
748 case Instruction::SRem:
749 if (CI2->isNullValue())
750 return 0; // X % 0 -> can't fold
751 if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
752 return 0; // MIN_INT % -1 -> overflow
753 return ConstantInt::get(C1V.srem(C2V));
754 case Instruction::And:
755 return ConstantInt::get(C1V & C2V);
756 case Instruction::Or:
757 return ConstantInt::get(C1V | C2V);
758 case Instruction::Xor:
759 return ConstantInt::get(C1V ^ C2V);
760 case Instruction::Shl: {
761 uint32_t shiftAmt = C2V.getZExtValue();
762 if (shiftAmt < C1V.getBitWidth())
763 return ConstantInt::get(C1V.shl(shiftAmt));
765 return UndefValue::get(C1->getType()); // too big shift is undef
767 case Instruction::LShr: {
768 uint32_t shiftAmt = C2V.getZExtValue();
769 if (shiftAmt < C1V.getBitWidth())
770 return ConstantInt::get(C1V.lshr(shiftAmt));
772 return UndefValue::get(C1->getType()); // too big shift is undef
774 case Instruction::AShr: {
775 uint32_t shiftAmt = C2V.getZExtValue();
776 if (shiftAmt < C1V.getBitWidth())
777 return ConstantInt::get(C1V.ashr(shiftAmt));
779 return UndefValue::get(C1->getType()); // too big shift is undef
783 } else if (const ConstantFP *CFP1 = dyn_cast<ConstantFP>(C1)) {
784 if (const ConstantFP *CFP2 = dyn_cast<ConstantFP>(C2)) {
785 APFloat C1V = CFP1->getValueAPF();
786 APFloat C2V = CFP2->getValueAPF();
787 APFloat C3V = C1V; // copy for modification
791 case Instruction::Add:
792 (void)C3V.add(C2V, APFloat::rmNearestTiesToEven);
793 return ConstantFP::get(C3V);
794 case Instruction::Sub:
795 (void)C3V.subtract(C2V, APFloat::rmNearestTiesToEven);
796 return ConstantFP::get(C3V);
797 case Instruction::Mul:
798 (void)C3V.multiply(C2V, APFloat::rmNearestTiesToEven);
799 return ConstantFP::get(C3V);
800 case Instruction::FDiv:
801 (void)C3V.divide(C2V, APFloat::rmNearestTiesToEven);
802 return ConstantFP::get(C3V);
803 case Instruction::FRem:
805 // IEEE 754, Section 7.1, #5
806 if (CFP1->getType() == Type::DoubleTy)
807 return ConstantFP::get(APFloat(std::numeric_limits<double>::
809 if (CFP1->getType() == Type::FloatTy)
810 return ConstantFP::get(APFloat(std::numeric_limits<float>::
814 (void)C3V.mod(C2V, APFloat::rmNearestTiesToEven);
815 return ConstantFP::get(C3V);
818 } else if (const VectorType *VTy = dyn_cast<VectorType>(C1->getType())) {
819 const ConstantVector *CP1 = dyn_cast<ConstantVector>(C1);
820 const ConstantVector *CP2 = dyn_cast<ConstantVector>(C2);
821 if ((CP1 != NULL || isa<ConstantAggregateZero>(C1)) &&
822 (CP2 != NULL || isa<ConstantAggregateZero>(C2))) {
826 case Instruction::Add:
827 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getAdd);
828 case Instruction::Sub:
829 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getSub);
830 case Instruction::Mul:
831 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getMul);
832 case Instruction::UDiv:
833 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getUDiv);
834 case Instruction::SDiv:
835 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getSDiv);
836 case Instruction::FDiv:
837 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getFDiv);
838 case Instruction::URem:
839 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getURem);
840 case Instruction::SRem:
841 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getSRem);
842 case Instruction::FRem:
843 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getFRem);
844 case Instruction::And:
845 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getAnd);
846 case Instruction::Or:
847 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getOr);
848 case Instruction::Xor:
849 return EvalVectorOp(CP1, CP2, VTy, ConstantExpr::getXor);
854 if (isa<ConstantExpr>(C1)) {
855 // There are many possible foldings we could do here. We should probably
856 // at least fold add of a pointer with an integer into the appropriate
857 // getelementptr. This will improve alias analysis a bit.
858 } else if (isa<ConstantExpr>(C2)) {
859 // If C2 is a constant expr and C1 isn't, flop them around and fold the
860 // other way if possible.
862 case Instruction::Add:
863 case Instruction::Mul:
864 case Instruction::And:
865 case Instruction::Or:
866 case Instruction::Xor:
867 // No change of opcode required.
868 return ConstantFoldBinaryInstruction(Opcode, C2, C1);
870 case Instruction::Shl:
871 case Instruction::LShr:
872 case Instruction::AShr:
873 case Instruction::Sub:
874 case Instruction::SDiv:
875 case Instruction::UDiv:
876 case Instruction::FDiv:
877 case Instruction::URem:
878 case Instruction::SRem:
879 case Instruction::FRem:
880 default: // These instructions cannot be flopped around.
885 // We don't know how to fold this.
889 /// isZeroSizedType - This type is zero sized if its an array or structure of
890 /// zero sized types. The only leaf zero sized type is an empty structure.
891 static bool isMaybeZeroSizedType(const Type *Ty) {
892 if (isa<OpaqueType>(Ty)) return true; // Can't say.
893 if (const StructType *STy = dyn_cast<StructType>(Ty)) {
895 // If all of elements have zero size, this does too.
896 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
897 if (!isMaybeZeroSizedType(STy->getElementType(i))) return false;
900 } else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
901 return isMaybeZeroSizedType(ATy->getElementType());
906 /// IdxCompare - Compare the two constants as though they were getelementptr
907 /// indices. This allows coersion of the types to be the same thing.
909 /// If the two constants are the "same" (after coersion), return 0. If the
910 /// first is less than the second, return -1, if the second is less than the
911 /// first, return 1. If the constants are not integral, return -2.
913 static int IdxCompare(Constant *C1, Constant *C2, const Type *ElTy) {
914 if (C1 == C2) return 0;
916 // Ok, we found a different index. If they are not ConstantInt, we can't do
917 // anything with them.
918 if (!isa<ConstantInt>(C1) || !isa<ConstantInt>(C2))
919 return -2; // don't know!
921 // Ok, we have two differing integer indices. Sign extend them to be the same
922 // type. Long is always big enough, so we use it.
923 if (C1->getType() != Type::Int64Ty)
924 C1 = ConstantExpr::getSExt(C1, Type::Int64Ty);
926 if (C2->getType() != Type::Int64Ty)
927 C2 = ConstantExpr::getSExt(C2, Type::Int64Ty);
929 if (C1 == C2) return 0; // They are equal
931 // If the type being indexed over is really just a zero sized type, there is
932 // no pointer difference being made here.
933 if (isMaybeZeroSizedType(ElTy))
936 // If they are really different, now that they are the same type, then we
937 // found a difference!
938 if (cast<ConstantInt>(C1)->getSExtValue() <
939 cast<ConstantInt>(C2)->getSExtValue())
945 /// evaluateFCmpRelation - This function determines if there is anything we can
946 /// decide about the two constants provided. This doesn't need to handle simple
947 /// things like ConstantFP comparisons, but should instead handle ConstantExprs.
948 /// If we can determine that the two constants have a particular relation to
949 /// each other, we should return the corresponding FCmpInst predicate,
950 /// otherwise return FCmpInst::BAD_FCMP_PREDICATE. This is used below in
951 /// ConstantFoldCompareInstruction.
953 /// To simplify this code we canonicalize the relation so that the first
954 /// operand is always the most "complex" of the two. We consider ConstantFP
955 /// to be the simplest, and ConstantExprs to be the most complex.
956 static FCmpInst::Predicate evaluateFCmpRelation(const Constant *V1,
957 const Constant *V2) {
958 assert(V1->getType() == V2->getType() &&
959 "Cannot compare values of different types!");
961 // No compile-time operations on this type yet.
962 if (V1->getType() == Type::PPC_FP128Ty)
963 return FCmpInst::BAD_FCMP_PREDICATE;
965 // Handle degenerate case quickly
966 if (V1 == V2) return FCmpInst::FCMP_OEQ;
968 if (!isa<ConstantExpr>(V1)) {
969 if (!isa<ConstantExpr>(V2)) {
970 // We distilled thisUse the standard constant folder for a few cases
972 Constant *C1 = const_cast<Constant*>(V1);
973 Constant *C2 = const_cast<Constant*>(V2);
974 R = dyn_cast<ConstantInt>(
975 ConstantExpr::getFCmp(FCmpInst::FCMP_OEQ, C1, C2));
976 if (R && !R->isZero())
977 return FCmpInst::FCMP_OEQ;
978 R = dyn_cast<ConstantInt>(
979 ConstantExpr::getFCmp(FCmpInst::FCMP_OLT, C1, C2));
980 if (R && !R->isZero())
981 return FCmpInst::FCMP_OLT;
982 R = dyn_cast<ConstantInt>(
983 ConstantExpr::getFCmp(FCmpInst::FCMP_OGT, C1, C2));
984 if (R && !R->isZero())
985 return FCmpInst::FCMP_OGT;
987 // Nothing more we can do
988 return FCmpInst::BAD_FCMP_PREDICATE;
991 // If the first operand is simple and second is ConstantExpr, swap operands.
992 FCmpInst::Predicate SwappedRelation = evaluateFCmpRelation(V2, V1);
993 if (SwappedRelation != FCmpInst::BAD_FCMP_PREDICATE)
994 return FCmpInst::getSwappedPredicate(SwappedRelation);
996 // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
997 // constantexpr or a simple constant.
998 const ConstantExpr *CE1 = cast<ConstantExpr>(V1);
999 switch (CE1->getOpcode()) {
1000 case Instruction::FPTrunc:
1001 case Instruction::FPExt:
1002 case Instruction::UIToFP:
1003 case Instruction::SIToFP:
1004 // We might be able to do something with these but we don't right now.
1010 // There are MANY other foldings that we could perform here. They will
1011 // probably be added on demand, as they seem needed.
1012 return FCmpInst::BAD_FCMP_PREDICATE;
1015 /// evaluateICmpRelation - This function determines if there is anything we can
1016 /// decide about the two constants provided. This doesn't need to handle simple
1017 /// things like integer comparisons, but should instead handle ConstantExprs
1018 /// and GlobalValues. If we can determine that the two constants have a
1019 /// particular relation to each other, we should return the corresponding ICmp
1020 /// predicate, otherwise return ICmpInst::BAD_ICMP_PREDICATE.
1022 /// To simplify this code we canonicalize the relation so that the first
1023 /// operand is always the most "complex" of the two. We consider simple
1024 /// constants (like ConstantInt) to be the simplest, followed by
1025 /// GlobalValues, followed by ConstantExpr's (the most complex).
1027 static ICmpInst::Predicate evaluateICmpRelation(const Constant *V1,
1030 assert(V1->getType() == V2->getType() &&
1031 "Cannot compare different types of values!");
1032 if (V1 == V2) return ICmpInst::ICMP_EQ;
1034 if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1)) {
1035 if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2)) {
1036 // We distilled this down to a simple case, use the standard constant
1039 Constant *C1 = const_cast<Constant*>(V1);
1040 Constant *C2 = const_cast<Constant*>(V2);
1041 ICmpInst::Predicate pred = ICmpInst::ICMP_EQ;
1042 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, C1, C2));
1043 if (R && !R->isZero())
1045 pred = isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1046 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, C1, C2));
1047 if (R && !R->isZero())
1049 pred = isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1050 R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, C1, C2));
1051 if (R && !R->isZero())
1054 // If we couldn't figure it out, bail.
1055 return ICmpInst::BAD_ICMP_PREDICATE;
1058 // If the first operand is simple, swap operands.
1059 ICmpInst::Predicate SwappedRelation =
1060 evaluateICmpRelation(V2, V1, isSigned);
1061 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1062 return ICmpInst::getSwappedPredicate(SwappedRelation);
1064 } else if (const GlobalValue *CPR1 = dyn_cast<GlobalValue>(V1)) {
1065 if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1066 ICmpInst::Predicate SwappedRelation =
1067 evaluateICmpRelation(V2, V1, isSigned);
1068 if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
1069 return ICmpInst::getSwappedPredicate(SwappedRelation);
1071 return ICmpInst::BAD_ICMP_PREDICATE;
1074 // Now we know that the RHS is a GlobalValue or simple constant,
1075 // which (since the types must match) means that it's a ConstantPointerNull.
1076 if (const GlobalValue *CPR2 = dyn_cast<GlobalValue>(V2)) {
1077 // Don't try to decide equality of aliases.
1078 if (!isa<GlobalAlias>(CPR1) && !isa<GlobalAlias>(CPR2))
1079 if (!CPR1->hasExternalWeakLinkage() || !CPR2->hasExternalWeakLinkage())
1080 return ICmpInst::ICMP_NE;
1082 assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!");
1083 // GlobalVals can never be null. Don't try to evaluate aliases.
1084 if (!CPR1->hasExternalWeakLinkage() && !isa<GlobalAlias>(CPR1))
1085 return ICmpInst::ICMP_NE;
1088 // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1089 // constantexpr, a CPR, or a simple constant.
1090 const ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1091 const Constant *CE1Op0 = CE1->getOperand(0);
1093 switch (CE1->getOpcode()) {
1094 case Instruction::Trunc:
1095 case Instruction::FPTrunc:
1096 case Instruction::FPExt:
1097 case Instruction::FPToUI:
1098 case Instruction::FPToSI:
1099 break; // We can't evaluate floating point casts or truncations.
1101 case Instruction::UIToFP:
1102 case Instruction::SIToFP:
1103 case Instruction::BitCast:
1104 case Instruction::ZExt:
1105 case Instruction::SExt:
1106 // If the cast is not actually changing bits, and the second operand is a
1107 // null pointer, do the comparison with the pre-casted value.
1108 if (V2->isNullValue() &&
1109 (isa<PointerType>(CE1->getType()) || CE1->getType()->isInteger())) {
1110 bool sgnd = isSigned;
1111 if (CE1->getOpcode() == Instruction::ZExt) isSigned = false;
1112 if (CE1->getOpcode() == Instruction::SExt) isSigned = true;
1113 return evaluateICmpRelation(CE1Op0,
1114 Constant::getNullValue(CE1Op0->getType()),
1118 // If the dest type is a pointer type, and the RHS is a constantexpr cast
1119 // from the same type as the src of the LHS, evaluate the inputs. This is
1120 // important for things like "icmp eq (cast 4 to int*), (cast 5 to int*)",
1121 // which happens a lot in compilers with tagged integers.
1122 if (const ConstantExpr *CE2 = dyn_cast<ConstantExpr>(V2))
1123 if (CE2->isCast() && isa<PointerType>(CE1->getType()) &&
1124 CE1->getOperand(0)->getType() == CE2->getOperand(0)->getType() &&
1125 CE1->getOperand(0)->getType()->isInteger()) {
1126 bool sgnd = isSigned;
1127 if (CE1->getOpcode() == Instruction::ZExt) isSigned = false;
1128 if (CE1->getOpcode() == Instruction::SExt) isSigned = true;
1129 return evaluateICmpRelation(CE1->getOperand(0), CE2->getOperand(0),
1134 case Instruction::GetElementPtr:
1135 // Ok, since this is a getelementptr, we know that the constant has a
1136 // pointer type. Check the various cases.
1137 if (isa<ConstantPointerNull>(V2)) {
1138 // If we are comparing a GEP to a null pointer, check to see if the base
1139 // of the GEP equals the null pointer.
1140 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
1141 if (GV->hasExternalWeakLinkage())
1142 // Weak linkage GVals could be zero or not. We're comparing that
1143 // to null pointer so its greater-or-equal
1144 return isSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE;
1146 // If its not weak linkage, the GVal must have a non-zero address
1147 // so the result is greater-than
1148 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1149 } else if (isa<ConstantPointerNull>(CE1Op0)) {
1150 // If we are indexing from a null pointer, check to see if we have any
1151 // non-zero indices.
1152 for (unsigned i = 1, e = CE1->getNumOperands(); i != e; ++i)
1153 if (!CE1->getOperand(i)->isNullValue())
1154 // Offsetting from null, must not be equal.
1155 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1156 // Only zero indexes from null, must still be zero.
1157 return ICmpInst::ICMP_EQ;
1159 // Otherwise, we can't really say if the first operand is null or not.
1160 } else if (const GlobalValue *CPR2 = dyn_cast<GlobalValue>(V2)) {
1161 if (isa<ConstantPointerNull>(CE1Op0)) {
1162 if (CPR2->hasExternalWeakLinkage())
1163 // Weak linkage GVals could be zero or not. We're comparing it to
1164 // a null pointer, so its less-or-equal
1165 return isSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE;
1167 // If its not weak linkage, the GVal must have a non-zero address
1168 // so the result is less-than
1169 return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1170 } else if (const GlobalValue *CPR1 = dyn_cast<GlobalValue>(CE1Op0)) {
1172 // If this is a getelementptr of the same global, then it must be
1173 // different. Because the types must match, the getelementptr could
1174 // only have at most one index, and because we fold getelementptr's
1175 // with a single zero index, it must be nonzero.
1176 assert(CE1->getNumOperands() == 2 &&
1177 !CE1->getOperand(1)->isNullValue() &&
1178 "Suprising getelementptr!");
1179 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1181 // If they are different globals, we don't know what the value is,
1182 // but they can't be equal.
1183 return ICmpInst::ICMP_NE;
1187 const ConstantExpr *CE2 = cast<ConstantExpr>(V2);
1188 const Constant *CE2Op0 = CE2->getOperand(0);
1190 // There are MANY other foldings that we could perform here. They will
1191 // probably be added on demand, as they seem needed.
1192 switch (CE2->getOpcode()) {
1194 case Instruction::GetElementPtr:
1195 // By far the most common case to handle is when the base pointers are
1196 // obviously to the same or different globals.
1197 if (isa<GlobalValue>(CE1Op0) && isa<GlobalValue>(CE2Op0)) {
1198 if (CE1Op0 != CE2Op0) // Don't know relative ordering, but not equal
1199 return ICmpInst::ICMP_NE;
1200 // Ok, we know that both getelementptr instructions are based on the
1201 // same global. From this, we can precisely determine the relative
1202 // ordering of the resultant pointers.
1205 // Compare all of the operands the GEP's have in common.
1206 gep_type_iterator GTI = gep_type_begin(CE1);
1207 for (;i != CE1->getNumOperands() && i != CE2->getNumOperands();
1209 switch (IdxCompare(CE1->getOperand(i), CE2->getOperand(i),
1210 GTI.getIndexedType())) {
1211 case -1: return isSigned ? ICmpInst::ICMP_SLT:ICmpInst::ICMP_ULT;
1212 case 1: return isSigned ? ICmpInst::ICMP_SGT:ICmpInst::ICMP_UGT;
1213 case -2: return ICmpInst::BAD_ICMP_PREDICATE;
1216 // Ok, we ran out of things they have in common. If any leftovers
1217 // are non-zero then we have a difference, otherwise we are equal.
1218 for (; i < CE1->getNumOperands(); ++i)
1219 if (!CE1->getOperand(i)->isNullValue()) {
1220 if (isa<ConstantInt>(CE1->getOperand(i)))
1221 return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
1223 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1226 for (; i < CE2->getNumOperands(); ++i)
1227 if (!CE2->getOperand(i)->isNullValue()) {
1228 if (isa<ConstantInt>(CE2->getOperand(i)))
1229 return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
1231 return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
1233 return ICmpInst::ICMP_EQ;
1242 return ICmpInst::BAD_ICMP_PREDICATE;
1245 Constant *llvm::ConstantFoldCompareInstruction(unsigned short pred,
1247 const Constant *C2) {
1248 // Fold FCMP_FALSE/FCMP_TRUE unconditionally.
1249 if (pred == FCmpInst::FCMP_FALSE) {
1250 if (const VectorType *VT = dyn_cast<VectorType>(C1->getType()))
1251 return Constant::getNullValue(VectorType::getInteger(VT));
1253 return ConstantInt::getFalse();
1256 if (pred == FCmpInst::FCMP_TRUE) {
1257 if (const VectorType *VT = dyn_cast<VectorType>(C1->getType()))
1258 return Constant::getAllOnesValue(VectorType::getInteger(VT));
1260 return ConstantInt::getTrue();
1263 // Handle some degenerate cases first
1264 if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
1265 // vicmp/vfcmp -> [vector] undef
1266 if (const VectorType *VTy = dyn_cast<VectorType>(C1->getType()))
1267 return UndefValue::get(VectorType::getInteger(VTy));
1269 // icmp/fcmp -> i1 undef
1270 return UndefValue::get(Type::Int1Ty);
1273 // No compile-time operations on this type yet.
1274 if (C1->getType() == Type::PPC_FP128Ty)
1277 // icmp eq/ne(null,GV) -> false/true
1278 if (C1->isNullValue()) {
1279 if (const GlobalValue *GV = dyn_cast<GlobalValue>(C2))
1280 // Don't try to evaluate aliases. External weak GV can be null.
1281 if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
1282 if (pred == ICmpInst::ICMP_EQ)
1283 return ConstantInt::getFalse();
1284 else if (pred == ICmpInst::ICMP_NE)
1285 return ConstantInt::getTrue();
1287 // icmp eq/ne(GV,null) -> false/true
1288 } else if (C2->isNullValue()) {
1289 if (const GlobalValue *GV = dyn_cast<GlobalValue>(C1))
1290 // Don't try to evaluate aliases. External weak GV can be null.
1291 if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
1292 if (pred == ICmpInst::ICMP_EQ)
1293 return ConstantInt::getFalse();
1294 else if (pred == ICmpInst::ICMP_NE)
1295 return ConstantInt::getTrue();
1299 if (isa<ConstantInt>(C1) && isa<ConstantInt>(C2)) {
1300 APInt V1 = cast<ConstantInt>(C1)->getValue();
1301 APInt V2 = cast<ConstantInt>(C2)->getValue();
1303 default: assert(0 && "Invalid ICmp Predicate"); return 0;
1304 case ICmpInst::ICMP_EQ: return ConstantInt::get(Type::Int1Ty, V1 == V2);
1305 case ICmpInst::ICMP_NE: return ConstantInt::get(Type::Int1Ty, V1 != V2);
1306 case ICmpInst::ICMP_SLT:return ConstantInt::get(Type::Int1Ty, V1.slt(V2));
1307 case ICmpInst::ICMP_SGT:return ConstantInt::get(Type::Int1Ty, V1.sgt(V2));
1308 case ICmpInst::ICMP_SLE:return ConstantInt::get(Type::Int1Ty, V1.sle(V2));
1309 case ICmpInst::ICMP_SGE:return ConstantInt::get(Type::Int1Ty, V1.sge(V2));
1310 case ICmpInst::ICMP_ULT:return ConstantInt::get(Type::Int1Ty, V1.ult(V2));
1311 case ICmpInst::ICMP_UGT:return ConstantInt::get(Type::Int1Ty, V1.ugt(V2));
1312 case ICmpInst::ICMP_ULE:return ConstantInt::get(Type::Int1Ty, V1.ule(V2));
1313 case ICmpInst::ICMP_UGE:return ConstantInt::get(Type::Int1Ty, V1.uge(V2));
1315 } else if (isa<ConstantFP>(C1) && isa<ConstantFP>(C2)) {
1316 APFloat C1V = cast<ConstantFP>(C1)->getValueAPF();
1317 APFloat C2V = cast<ConstantFP>(C2)->getValueAPF();
1318 APFloat::cmpResult R = C1V.compare(C2V);
1320 default: assert(0 && "Invalid FCmp Predicate"); return 0;
1321 case FCmpInst::FCMP_FALSE: return ConstantInt::getFalse();
1322 case FCmpInst::FCMP_TRUE: return ConstantInt::getTrue();
1323 case FCmpInst::FCMP_UNO:
1324 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpUnordered);
1325 case FCmpInst::FCMP_ORD:
1326 return ConstantInt::get(Type::Int1Ty, R!=APFloat::cmpUnordered);
1327 case FCmpInst::FCMP_UEQ:
1328 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpUnordered ||
1329 R==APFloat::cmpEqual);
1330 case FCmpInst::FCMP_OEQ:
1331 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpEqual);
1332 case FCmpInst::FCMP_UNE:
1333 return ConstantInt::get(Type::Int1Ty, R!=APFloat::cmpEqual);
1334 case FCmpInst::FCMP_ONE:
1335 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpLessThan ||
1336 R==APFloat::cmpGreaterThan);
1337 case FCmpInst::FCMP_ULT:
1338 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpUnordered ||
1339 R==APFloat::cmpLessThan);
1340 case FCmpInst::FCMP_OLT:
1341 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpLessThan);
1342 case FCmpInst::FCMP_UGT:
1343 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpUnordered ||
1344 R==APFloat::cmpGreaterThan);
1345 case FCmpInst::FCMP_OGT:
1346 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpGreaterThan);
1347 case FCmpInst::FCMP_ULE:
1348 return ConstantInt::get(Type::Int1Ty, R!=APFloat::cmpGreaterThan);
1349 case FCmpInst::FCMP_OLE:
1350 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpLessThan ||
1351 R==APFloat::cmpEqual);
1352 case FCmpInst::FCMP_UGE:
1353 return ConstantInt::get(Type::Int1Ty, R!=APFloat::cmpLessThan);
1354 case FCmpInst::FCMP_OGE:
1355 return ConstantInt::get(Type::Int1Ty, R==APFloat::cmpGreaterThan ||
1356 R==APFloat::cmpEqual);
1358 } else if (isa<VectorType>(C1->getType())) {
1359 SmallVector<Constant*, 16> C1Elts, C2Elts;
1360 C1->getVectorElements(C1Elts);
1361 C2->getVectorElements(C2Elts);
1363 // If we can constant fold the comparison of each element, constant fold
1364 // the whole vector comparison.
1365 SmallVector<Constant*, 4> ResElts;
1366 const Type *InEltTy = C1Elts[0]->getType();
1367 bool isFP = InEltTy->isFloatingPoint();
1368 const Type *ResEltTy = InEltTy;
1370 ResEltTy = IntegerType::get(InEltTy->getPrimitiveSizeInBits());
1372 for (unsigned i = 0, e = C1Elts.size(); i != e; ++i) {
1373 // Compare the elements, producing an i1 result or constant expr.
1376 C = ConstantExpr::getFCmp(pred, C1Elts[i], C2Elts[i]);
1378 C = ConstantExpr::getICmp(pred, C1Elts[i], C2Elts[i]);
1380 // If it is a bool or undef result, convert to the dest type.
1381 if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
1383 ResElts.push_back(Constant::getNullValue(ResEltTy));
1385 ResElts.push_back(Constant::getAllOnesValue(ResEltTy));
1386 } else if (isa<UndefValue>(C)) {
1387 ResElts.push_back(UndefValue::get(ResEltTy));
1393 if (ResElts.size() == C1Elts.size())
1394 return ConstantVector::get(&ResElts[0], ResElts.size());
1397 if (C1->getType()->isFloatingPoint()) {
1398 int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
1399 switch (evaluateFCmpRelation(C1, C2)) {
1400 default: assert(0 && "Unknown relation!");
1401 case FCmpInst::FCMP_UNO:
1402 case FCmpInst::FCMP_ORD:
1403 case FCmpInst::FCMP_UEQ:
1404 case FCmpInst::FCMP_UNE:
1405 case FCmpInst::FCMP_ULT:
1406 case FCmpInst::FCMP_UGT:
1407 case FCmpInst::FCMP_ULE:
1408 case FCmpInst::FCMP_UGE:
1409 case FCmpInst::FCMP_TRUE:
1410 case FCmpInst::FCMP_FALSE:
1411 case FCmpInst::BAD_FCMP_PREDICATE:
1412 break; // Couldn't determine anything about these constants.
1413 case FCmpInst::FCMP_OEQ: // We know that C1 == C2
1414 Result = (pred == FCmpInst::FCMP_UEQ || pred == FCmpInst::FCMP_OEQ ||
1415 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE ||
1416 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
1418 case FCmpInst::FCMP_OLT: // We know that C1 < C2
1419 Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
1420 pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT ||
1421 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE);
1423 case FCmpInst::FCMP_OGT: // We know that C1 > C2
1424 Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
1425 pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT ||
1426 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
1428 case FCmpInst::FCMP_OLE: // We know that C1 <= C2
1429 // We can only partially decide this relation.
1430 if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
1432 else if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
1435 case FCmpInst::FCMP_OGE: // We known that C1 >= C2
1436 // We can only partially decide this relation.
1437 if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
1439 else if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
1442 case ICmpInst::ICMP_NE: // We know that C1 != C2
1443 // We can only partially decide this relation.
1444 if (pred == FCmpInst::FCMP_OEQ || pred == FCmpInst::FCMP_UEQ)
1446 else if (pred == FCmpInst::FCMP_ONE || pred == FCmpInst::FCMP_UNE)
1451 // If we evaluated the result, return it now.
1453 if (const VectorType *VT = dyn_cast<VectorType>(C1->getType())) {
1455 return Constant::getNullValue(VectorType::getInteger(VT));
1457 return Constant::getAllOnesValue(VectorType::getInteger(VT));
1459 return ConstantInt::get(Type::Int1Ty, Result);
1463 // Evaluate the relation between the two constants, per the predicate.
1464 int Result = -1; // -1 = unknown, 0 = known false, 1 = known true.
1465 switch (evaluateICmpRelation(C1, C2, CmpInst::isSigned(pred))) {
1466 default: assert(0 && "Unknown relational!");
1467 case ICmpInst::BAD_ICMP_PREDICATE:
1468 break; // Couldn't determine anything about these constants.
1469 case ICmpInst::ICMP_EQ: // We know the constants are equal!
1470 // If we know the constants are equal, we can decide the result of this
1471 // computation precisely.
1472 Result = (pred == ICmpInst::ICMP_EQ ||
1473 pred == ICmpInst::ICMP_ULE ||
1474 pred == ICmpInst::ICMP_SLE ||
1475 pred == ICmpInst::ICMP_UGE ||
1476 pred == ICmpInst::ICMP_SGE);
1478 case ICmpInst::ICMP_ULT:
1479 // If we know that C1 < C2, we can decide the result of this computation
1481 Result = (pred == ICmpInst::ICMP_ULT ||
1482 pred == ICmpInst::ICMP_NE ||
1483 pred == ICmpInst::ICMP_ULE);
1485 case ICmpInst::ICMP_SLT:
1486 // If we know that C1 < C2, we can decide the result of this computation
1488 Result = (pred == ICmpInst::ICMP_SLT ||
1489 pred == ICmpInst::ICMP_NE ||
1490 pred == ICmpInst::ICMP_SLE);
1492 case ICmpInst::ICMP_UGT:
1493 // If we know that C1 > C2, we can decide the result of this computation
1495 Result = (pred == ICmpInst::ICMP_UGT ||
1496 pred == ICmpInst::ICMP_NE ||
1497 pred == ICmpInst::ICMP_UGE);
1499 case ICmpInst::ICMP_SGT:
1500 // If we know that C1 > C2, we can decide the result of this computation
1502 Result = (pred == ICmpInst::ICMP_SGT ||
1503 pred == ICmpInst::ICMP_NE ||
1504 pred == ICmpInst::ICMP_SGE);
1506 case ICmpInst::ICMP_ULE:
1507 // If we know that C1 <= C2, we can only partially decide this relation.
1508 if (pred == ICmpInst::ICMP_UGT) Result = 0;
1509 if (pred == ICmpInst::ICMP_ULT) Result = 1;
1511 case ICmpInst::ICMP_SLE:
1512 // If we know that C1 <= C2, we can only partially decide this relation.
1513 if (pred == ICmpInst::ICMP_SGT) Result = 0;
1514 if (pred == ICmpInst::ICMP_SLT) Result = 1;
1517 case ICmpInst::ICMP_UGE:
1518 // If we know that C1 >= C2, we can only partially decide this relation.
1519 if (pred == ICmpInst::ICMP_ULT) Result = 0;
1520 if (pred == ICmpInst::ICMP_UGT) Result = 1;
1522 case ICmpInst::ICMP_SGE:
1523 // If we know that C1 >= C2, we can only partially decide this relation.
1524 if (pred == ICmpInst::ICMP_SLT) Result = 0;
1525 if (pred == ICmpInst::ICMP_SGT) Result = 1;
1528 case ICmpInst::ICMP_NE:
1529 // If we know that C1 != C2, we can only partially decide this relation.
1530 if (pred == ICmpInst::ICMP_EQ) Result = 0;
1531 if (pred == ICmpInst::ICMP_NE) Result = 1;
1535 // If we evaluated the result, return it now.
1537 if (const VectorType *VT = dyn_cast<VectorType>(C1->getType())) {
1539 return Constant::getNullValue(VT);
1541 return Constant::getAllOnesValue(VT);
1543 return ConstantInt::get(Type::Int1Ty, Result);
1546 if (!isa<ConstantExpr>(C1) && isa<ConstantExpr>(C2)) {
1547 // If C2 is a constant expr and C1 isn't, flop them around and fold the
1548 // other way if possible.
1550 case ICmpInst::ICMP_EQ:
1551 case ICmpInst::ICMP_NE:
1552 // No change of predicate required.
1553 return ConstantFoldCompareInstruction(pred, C2, C1);
1555 case ICmpInst::ICMP_ULT:
1556 case ICmpInst::ICMP_SLT:
1557 case ICmpInst::ICMP_UGT:
1558 case ICmpInst::ICMP_SGT:
1559 case ICmpInst::ICMP_ULE:
1560 case ICmpInst::ICMP_SLE:
1561 case ICmpInst::ICMP_UGE:
1562 case ICmpInst::ICMP_SGE:
1563 // Change the predicate as necessary to swap the operands.
1564 pred = ICmpInst::getSwappedPredicate((ICmpInst::Predicate)pred);
1565 return ConstantFoldCompareInstruction(pred, C2, C1);
1567 default: // These predicates cannot be flopped around.
1575 Constant *llvm::ConstantFoldGetElementPtr(const Constant *C,
1576 Constant* const *Idxs,
1579 (NumIdx == 1 && Idxs[0]->isNullValue()))
1580 return const_cast<Constant*>(C);
1582 if (isa<UndefValue>(C)) {
1583 const PointerType *Ptr = cast<PointerType>(C->getType());
1584 const Type *Ty = GetElementPtrInst::getIndexedType(Ptr,
1586 (Value **)Idxs+NumIdx);
1587 assert(Ty != 0 && "Invalid indices for GEP!");
1588 return UndefValue::get(PointerType::get(Ty, Ptr->getAddressSpace()));
1591 Constant *Idx0 = Idxs[0];
1592 if (C->isNullValue()) {
1594 for (unsigned i = 0, e = NumIdx; i != e; ++i)
1595 if (!Idxs[i]->isNullValue()) {
1600 const PointerType *Ptr = cast<PointerType>(C->getType());
1601 const Type *Ty = GetElementPtrInst::getIndexedType(Ptr,
1603 (Value**)Idxs+NumIdx);
1604 assert(Ty != 0 && "Invalid indices for GEP!");
1606 ConstantPointerNull::get(PointerType::get(Ty,Ptr->getAddressSpace()));
1610 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(const_cast<Constant*>(C))) {
1611 // Combine Indices - If the source pointer to this getelementptr instruction
1612 // is a getelementptr instruction, combine the indices of the two
1613 // getelementptr instructions into a single instruction.
1615 if (CE->getOpcode() == Instruction::GetElementPtr) {
1616 const Type *LastTy = 0;
1617 for (gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
1621 if ((LastTy && isa<ArrayType>(LastTy)) || Idx0->isNullValue()) {
1622 SmallVector<Value*, 16> NewIndices;
1623 NewIndices.reserve(NumIdx + CE->getNumOperands());
1624 for (unsigned i = 1, e = CE->getNumOperands()-1; i != e; ++i)
1625 NewIndices.push_back(CE->getOperand(i));
1627 // Add the last index of the source with the first index of the new GEP.
1628 // Make sure to handle the case when they are actually different types.
1629 Constant *Combined = CE->getOperand(CE->getNumOperands()-1);
1630 // Otherwise it must be an array.
1631 if (!Idx0->isNullValue()) {
1632 const Type *IdxTy = Combined->getType();
1633 if (IdxTy != Idx0->getType()) {
1634 Constant *C1 = ConstantExpr::getSExtOrBitCast(Idx0, Type::Int64Ty);
1635 Constant *C2 = ConstantExpr::getSExtOrBitCast(Combined,
1637 Combined = ConstantExpr::get(Instruction::Add, C1, C2);
1640 ConstantExpr::get(Instruction::Add, Idx0, Combined);
1644 NewIndices.push_back(Combined);
1645 NewIndices.insert(NewIndices.end(), Idxs+1, Idxs+NumIdx);
1646 return ConstantExpr::getGetElementPtr(CE->getOperand(0), &NewIndices[0],
1651 // Implement folding of:
1652 // int* getelementptr ([2 x int]* cast ([3 x int]* %X to [2 x int]*),
1654 // To: int* getelementptr ([3 x int]* %X, long 0, long 0)
1656 if (CE->isCast() && NumIdx > 1 && Idx0->isNullValue()) {
1657 if (const PointerType *SPT =
1658 dyn_cast<PointerType>(CE->getOperand(0)->getType()))
1659 if (const ArrayType *SAT = dyn_cast<ArrayType>(SPT->getElementType()))
1660 if (const ArrayType *CAT =
1661 dyn_cast<ArrayType>(cast<PointerType>(C->getType())->getElementType()))
1662 if (CAT->getElementType() == SAT->getElementType())
1663 return ConstantExpr::getGetElementPtr(
1664 (Constant*)CE->getOperand(0), Idxs, NumIdx);
1667 // Fold: getelementptr (i8* inttoptr (i64 1 to i8*), i32 -1)
1668 // Into: inttoptr (i64 0 to i8*)
1669 // This happens with pointers to member functions in C++.
1670 if (CE->getOpcode() == Instruction::IntToPtr && NumIdx == 1 &&
1671 isa<ConstantInt>(CE->getOperand(0)) && isa<ConstantInt>(Idxs[0]) &&
1672 cast<PointerType>(CE->getType())->getElementType() == Type::Int8Ty) {
1673 Constant *Base = CE->getOperand(0);
1674 Constant *Offset = Idxs[0];
1676 // Convert the smaller integer to the larger type.
1677 if (Offset->getType()->getPrimitiveSizeInBits() <
1678 Base->getType()->getPrimitiveSizeInBits())
1679 Offset = ConstantExpr::getSExt(Offset, Base->getType());
1680 else if (Base->getType()->getPrimitiveSizeInBits() <
1681 Offset->getType()->getPrimitiveSizeInBits())
1682 Base = ConstantExpr::getZExt(Base, Base->getType());
1684 Base = ConstantExpr::getAdd(Base, Offset);
1685 return ConstantExpr::getIntToPtr(Base, CE->getType());