| //===- ConstantFolding.cpp - LLVM constant folder -------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by the LLVM research group and is distributed under |
| // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements folding of constants for LLVM. This implements the |
| // (internal) ConstantFolding.h interface, which is used by the |
| // ConstantExpr::get* methods to automatically fold constants when possible. |
| // |
| // The current constant folding implementation is implemented in two pieces: the |
| // template-based folder for simple primitive constants like ConstantInt, and |
| // the special case hackery that we use to symbolically evaluate expressions |
| // that use ConstantExprs. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "ConstantFolding.h" |
| #include "llvm/Constants.h" |
| #include "llvm/Instructions.h" |
| #include "llvm/DerivedTypes.h" |
| #include "llvm/Function.h" |
| #include "llvm/Support/Compiler.h" |
| #include "llvm/Support/GetElementPtrTypeIterator.h" |
| #include "llvm/Support/ManagedStatic.h" |
| #include "llvm/Support/MathExtras.h" |
| #include <limits> |
| using namespace llvm; |
| |
| namespace { |
| struct VISIBILITY_HIDDEN ConstRules { |
| ConstRules() {} |
| virtual ~ConstRules() {} |
| |
| // Binary Operators... |
| virtual Constant *add(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *sub(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *mul(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *urem(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *srem(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *frem(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *udiv(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *sdiv(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *fdiv(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *op_and(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *op_or (const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *op_xor(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *shl(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *lshr(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *ashr(const Constant *V1, const Constant *V2) const = 0; |
| virtual Constant *lessthan(const Constant *V1, const Constant *V2) const =0; |
| virtual Constant *equalto(const Constant *V1, const Constant *V2) const = 0; |
| |
| // Casting operators. |
| virtual Constant *castToBool (const Constant *V) const = 0; |
| virtual Constant *castToSByte (const Constant *V) const = 0; |
| virtual Constant *castToUByte (const Constant *V) const = 0; |
| virtual Constant *castToShort (const Constant *V) const = 0; |
| virtual Constant *castToUShort(const Constant *V) const = 0; |
| virtual Constant *castToInt (const Constant *V) const = 0; |
| virtual Constant *castToUInt (const Constant *V) const = 0; |
| virtual Constant *castToLong (const Constant *V) const = 0; |
| virtual Constant *castToULong (const Constant *V) const = 0; |
| virtual Constant *castToFloat (const Constant *V) const = 0; |
| virtual Constant *castToDouble(const Constant *V) const = 0; |
| virtual Constant *castToPointer(const Constant *V, |
| const PointerType *Ty) const = 0; |
| |
| // ConstRules::get - Return an instance of ConstRules for the specified |
| // constant operands. |
| // |
| static ConstRules &get(const Constant *V1, const Constant *V2); |
| private: |
| ConstRules(const ConstRules &); // Do not implement |
| ConstRules &operator=(const ConstRules &); // Do not implement |
| }; |
| } |
| |
| |
| //===----------------------------------------------------------------------===// |
| // TemplateRules Class |
| //===----------------------------------------------------------------------===// |
| // |
| // TemplateRules - Implement a subclass of ConstRules that provides all |
| // operations as noops. All other rules classes inherit from this class so |
| // that if functionality is needed in the future, it can simply be added here |
| // and to ConstRules without changing anything else... |
| // |
| // This class also provides subclasses with typesafe implementations of methods |
| // so that don't have to do type casting. |
| // |
| namespace { |
| template<class ArgType, class SubClassName> |
| class VISIBILITY_HIDDEN TemplateRules : public ConstRules { |
| |
| |
| //===--------------------------------------------------------------------===// |
| // Redirecting functions that cast to the appropriate types |
| //===--------------------------------------------------------------------===// |
| |
| virtual Constant *add(const Constant *V1, const Constant *V2) const { |
| return SubClassName::Add((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *sub(const Constant *V1, const Constant *V2) const { |
| return SubClassName::Sub((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *mul(const Constant *V1, const Constant *V2) const { |
| return SubClassName::Mul((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *udiv(const Constant *V1, const Constant *V2) const { |
| return SubClassName::UDiv((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *sdiv(const Constant *V1, const Constant *V2) const { |
| return SubClassName::SDiv((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *fdiv(const Constant *V1, const Constant *V2) const { |
| return SubClassName::FDiv((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *urem(const Constant *V1, const Constant *V2) const { |
| return SubClassName::URem((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *srem(const Constant *V1, const Constant *V2) const { |
| return SubClassName::SRem((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *frem(const Constant *V1, const Constant *V2) const { |
| return SubClassName::FRem((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *op_and(const Constant *V1, const Constant *V2) const { |
| return SubClassName::And((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *op_or(const Constant *V1, const Constant *V2) const { |
| return SubClassName::Or((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *op_xor(const Constant *V1, const Constant *V2) const { |
| return SubClassName::Xor((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *shl(const Constant *V1, const Constant *V2) const { |
| return SubClassName::Shl((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *lshr(const Constant *V1, const Constant *V2) const { |
| return SubClassName::LShr((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *ashr(const Constant *V1, const Constant *V2) const { |
| return SubClassName::AShr((const ArgType *)V1, (const ArgType *)V2); |
| } |
| |
| virtual Constant *lessthan(const Constant *V1, const Constant *V2) const { |
| return SubClassName::LessThan((const ArgType *)V1, (const ArgType *)V2); |
| } |
| virtual Constant *equalto(const Constant *V1, const Constant *V2) const { |
| return SubClassName::EqualTo((const ArgType *)V1, (const ArgType *)V2); |
| } |
| |
| // Casting operators. ick |
| virtual Constant *castToBool(const Constant *V) const { |
| return SubClassName::CastToBool((const ArgType*)V); |
| } |
| virtual Constant *castToSByte(const Constant *V) const { |
| return SubClassName::CastToSByte((const ArgType*)V); |
| } |
| virtual Constant *castToUByte(const Constant *V) const { |
| return SubClassName::CastToUByte((const ArgType*)V); |
| } |
| virtual Constant *castToShort(const Constant *V) const { |
| return SubClassName::CastToShort((const ArgType*)V); |
| } |
| virtual Constant *castToUShort(const Constant *V) const { |
| return SubClassName::CastToUShort((const ArgType*)V); |
| } |
| virtual Constant *castToInt(const Constant *V) const { |
| return SubClassName::CastToInt((const ArgType*)V); |
| } |
| virtual Constant *castToUInt(const Constant *V) const { |
| return SubClassName::CastToUInt((const ArgType*)V); |
| } |
| virtual Constant *castToLong(const Constant *V) const { |
| return SubClassName::CastToLong((const ArgType*)V); |
| } |
| virtual Constant *castToULong(const Constant *V) const { |
| return SubClassName::CastToULong((const ArgType*)V); |
| } |
| virtual Constant *castToFloat(const Constant *V) const { |
| return SubClassName::CastToFloat((const ArgType*)V); |
| } |
| virtual Constant *castToDouble(const Constant *V) const { |
| return SubClassName::CastToDouble((const ArgType*)V); |
| } |
| virtual Constant *castToPointer(const Constant *V, |
| const PointerType *Ty) const { |
| return SubClassName::CastToPointer((const ArgType*)V, Ty); |
| } |
| |
| //===--------------------------------------------------------------------===// |
| // Default "noop" implementations |
| //===--------------------------------------------------------------------===// |
| |
| static Constant *Add (const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *Sub (const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *Mul (const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *SDiv(const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *UDiv(const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *FDiv(const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *URem(const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *SRem(const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *FRem(const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *And (const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *Or (const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *Xor (const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *Shl (const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *LShr(const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *AShr(const ArgType *V1, const ArgType *V2) { return 0; } |
| static Constant *LessThan(const ArgType *V1, const ArgType *V2) { |
| return 0; |
| } |
| static Constant *EqualTo(const ArgType *V1, const ArgType *V2) { |
| return 0; |
| } |
| |
| // Casting operators. ick |
| static Constant *CastToBool (const Constant *V) { return 0; } |
| static Constant *CastToSByte (const Constant *V) { return 0; } |
| static Constant *CastToUByte (const Constant *V) { return 0; } |
| static Constant *CastToShort (const Constant *V) { return 0; } |
| static Constant *CastToUShort(const Constant *V) { return 0; } |
| static Constant *CastToInt (const Constant *V) { return 0; } |
| static Constant *CastToUInt (const Constant *V) { return 0; } |
| static Constant *CastToLong (const Constant *V) { return 0; } |
| static Constant *CastToULong (const Constant *V) { return 0; } |
| static Constant *CastToFloat (const Constant *V) { return 0; } |
| static Constant *CastToDouble(const Constant *V) { return 0; } |
| static Constant *CastToPointer(const Constant *, |
| const PointerType *) {return 0;} |
| |
| public: |
| virtual ~TemplateRules() {} |
| }; |
| } // end anonymous namespace |
| |
| |
| //===----------------------------------------------------------------------===// |
| // EmptyRules Class |
| //===----------------------------------------------------------------------===// |
| // |
| // EmptyRules provides a concrete base class of ConstRules that does nothing |
| // |
| namespace { |
| struct VISIBILITY_HIDDEN EmptyRules |
| : public TemplateRules<Constant, EmptyRules> { |
| static Constant *EqualTo(const Constant *V1, const Constant *V2) { |
| if (V1 == V2) return ConstantBool::getTrue(); |
| return 0; |
| } |
| }; |
| } // end anonymous namespace |
| |
| |
| |
| //===----------------------------------------------------------------------===// |
| // BoolRules Class |
| //===----------------------------------------------------------------------===// |
| // |
| // BoolRules provides a concrete base class of ConstRules for the 'bool' type. |
| // |
| namespace { |
| struct VISIBILITY_HIDDEN BoolRules |
| : public TemplateRules<ConstantBool, BoolRules> { |
| |
| static Constant *LessThan(const ConstantBool *V1, const ConstantBool *V2) { |
| return ConstantBool::get(V1->getValue() < V2->getValue()); |
| } |
| |
| static Constant *EqualTo(const Constant *V1, const Constant *V2) { |
| return ConstantBool::get(V1 == V2); |
| } |
| |
| static Constant *And(const ConstantBool *V1, const ConstantBool *V2) { |
| return ConstantBool::get(V1->getValue() & V2->getValue()); |
| } |
| |
| static Constant *Or(const ConstantBool *V1, const ConstantBool *V2) { |
| return ConstantBool::get(V1->getValue() | V2->getValue()); |
| } |
| |
| static Constant *Xor(const ConstantBool *V1, const ConstantBool *V2) { |
| return ConstantBool::get(V1->getValue() ^ V2->getValue()); |
| } |
| |
| // Casting operators. ick |
| #define DEF_CAST(TYPE, CLASS, CTYPE) \ |
| static Constant *CastTo##TYPE (const ConstantBool *V) { \ |
| return CLASS::get(Type::TYPE##Ty, (CTYPE)(bool)V->getValue()); \ |
| } |
| |
| DEF_CAST(Bool , ConstantBool, bool) |
| DEF_CAST(SByte , ConstantInt, signed char) |
| DEF_CAST(UByte , ConstantInt, unsigned char) |
| DEF_CAST(Short , ConstantInt, signed short) |
| DEF_CAST(UShort, ConstantInt, unsigned short) |
| DEF_CAST(Int , ConstantInt, signed int) |
| DEF_CAST(UInt , ConstantInt, unsigned int) |
| DEF_CAST(Long , ConstantInt, int64_t) |
| DEF_CAST(ULong , ConstantInt, uint64_t) |
| DEF_CAST(Float , ConstantFP , float) |
| DEF_CAST(Double, ConstantFP , double) |
| #undef DEF_CAST |
| }; |
| } // end anonymous namespace |
| |
| |
| //===----------------------------------------------------------------------===// |
| // NullPointerRules Class |
| //===----------------------------------------------------------------------===// |
| // |
| // NullPointerRules provides a concrete base class of ConstRules for null |
| // pointers. |
| // |
| namespace { |
| struct VISIBILITY_HIDDEN NullPointerRules |
| : public TemplateRules<ConstantPointerNull, NullPointerRules> { |
| static Constant *EqualTo(const Constant *V1, const Constant *V2) { |
| return ConstantBool::getTrue(); // Null pointers are always equal |
| } |
| static Constant *CastToBool(const Constant *V) { |
| return ConstantBool::getFalse(); |
| } |
| static Constant *CastToSByte (const Constant *V) { |
| return ConstantInt::get(Type::SByteTy, 0); |
| } |
| static Constant *CastToUByte (const Constant *V) { |
| return ConstantInt::get(Type::UByteTy, 0); |
| } |
| static Constant *CastToShort (const Constant *V) { |
| return ConstantInt::get(Type::ShortTy, 0); |
| } |
| static Constant *CastToUShort(const Constant *V) { |
| return ConstantInt::get(Type::UShortTy, 0); |
| } |
| static Constant *CastToInt (const Constant *V) { |
| return ConstantInt::get(Type::IntTy, 0); |
| } |
| static Constant *CastToUInt (const Constant *V) { |
| return ConstantInt::get(Type::UIntTy, 0); |
| } |
| static Constant *CastToLong (const Constant *V) { |
| return ConstantInt::get(Type::LongTy, 0); |
| } |
| static Constant *CastToULong (const Constant *V) { |
| return ConstantInt::get(Type::ULongTy, 0); |
| } |
| static Constant *CastToFloat (const Constant *V) { |
| return ConstantFP::get(Type::FloatTy, 0); |
| } |
| static Constant *CastToDouble(const Constant *V) { |
| return ConstantFP::get(Type::DoubleTy, 0); |
| } |
| |
| static Constant *CastToPointer(const ConstantPointerNull *V, |
| const PointerType *PTy) { |
| return ConstantPointerNull::get(PTy); |
| } |
| }; |
| } // end anonymous namespace |
| |
| //===----------------------------------------------------------------------===// |
| // ConstantPackedRules Class |
| //===----------------------------------------------------------------------===// |
| |
| /// DoVectorOp - Given two packed constants and a function pointer, apply the |
| /// function pointer to each element pair, producing a new ConstantPacked |
| /// constant. |
| static Constant *EvalVectorOp(const ConstantPacked *V1, |
| const ConstantPacked *V2, |
| Constant *(*FP)(Constant*, Constant*)) { |
| std::vector<Constant*> Res; |
| for (unsigned i = 0, e = V1->getNumOperands(); i != e; ++i) |
| Res.push_back(FP(const_cast<Constant*>(V1->getOperand(i)), |
| const_cast<Constant*>(V2->getOperand(i)))); |
| return ConstantPacked::get(Res); |
| } |
| |
| /// PackedTypeRules provides a concrete base class of ConstRules for |
| /// ConstantPacked operands. |
| /// |
| namespace { |
| struct VISIBILITY_HIDDEN ConstantPackedRules |
| : public TemplateRules<ConstantPacked, ConstantPackedRules> { |
| |
| static Constant *Add(const ConstantPacked *V1, const ConstantPacked *V2) { |
| return EvalVectorOp(V1, V2, ConstantExpr::getAdd); |
| } |
| static Constant *Sub(const ConstantPacked *V1, const ConstantPacked *V2) { |
| return EvalVectorOp(V1, V2, ConstantExpr::getSub); |
| } |
| static Constant *Mul(const ConstantPacked *V1, const ConstantPacked *V2) { |
| return EvalVectorOp(V1, V2, ConstantExpr::getMul); |
| } |
| static Constant *UDiv(const ConstantPacked *V1, const ConstantPacked *V2) { |
| return EvalVectorOp(V1, V2, ConstantExpr::getUDiv); |
| } |
| static Constant *SDiv(const ConstantPacked *V1, const ConstantPacked *V2) { |
| return EvalVectorOp(V1, V2, ConstantExpr::getSDiv); |
| } |
| static Constant *FDiv(const ConstantPacked *V1, const ConstantPacked *V2) { |
| return EvalVectorOp(V1, V2, ConstantExpr::getFDiv); |
| } |
| static Constant *URem(const ConstantPacked *V1, const ConstantPacked *V2) { |
| return EvalVectorOp(V1, V2, ConstantExpr::getURem); |
| } |
| static Constant *SRem(const ConstantPacked *V1, const ConstantPacked *V2) { |
| return EvalVectorOp(V1, V2, ConstantExpr::getSRem); |
| } |
| static Constant *FRem(const ConstantPacked *V1, const ConstantPacked *V2) { |
| return EvalVectorOp(V1, V2, ConstantExpr::getFRem); |
| } |
| static Constant *And(const ConstantPacked *V1, const ConstantPacked *V2) { |
| return EvalVectorOp(V1, V2, ConstantExpr::getAnd); |
| } |
| static Constant *Or (const ConstantPacked *V1, const ConstantPacked *V2) { |
| return EvalVectorOp(V1, V2, ConstantExpr::getOr); |
| } |
| static Constant *Xor(const ConstantPacked *V1, const ConstantPacked *V2) { |
| return EvalVectorOp(V1, V2, ConstantExpr::getXor); |
| } |
| static Constant *LessThan(const ConstantPacked *V1, const ConstantPacked *V2){ |
| return 0; |
| } |
| static Constant *EqualTo(const ConstantPacked *V1, const ConstantPacked *V2) { |
| for (unsigned i = 0, e = V1->getNumOperands(); i != e; ++i) { |
| Constant *C = |
| ConstantExpr::getSetEQ(const_cast<Constant*>(V1->getOperand(i)), |
| const_cast<Constant*>(V2->getOperand(i))); |
| if (ConstantBool *CB = dyn_cast<ConstantBool>(C)) |
| return CB; |
| } |
| // Otherwise, could not decide from any element pairs. |
| return 0; |
| } |
| }; |
| } // end anonymous namespace |
| |
| |
| //===----------------------------------------------------------------------===// |
| // GeneralPackedRules Class |
| //===----------------------------------------------------------------------===// |
| |
| /// GeneralPackedRules provides a concrete base class of ConstRules for |
| /// PackedType operands, where both operands are not ConstantPacked. The usual |
| /// cause for this is that one operand is a ConstantAggregateZero. |
| /// |
| namespace { |
| struct VISIBILITY_HIDDEN GeneralPackedRules |
| : public TemplateRules<Constant, GeneralPackedRules> { |
| }; |
| } // end anonymous namespace |
| |
| |
| //===----------------------------------------------------------------------===// |
| // DirectIntRules Class |
| //===----------------------------------------------------------------------===// |
| // |
| // DirectIntRules provides implementations of functions that are valid on |
| // integer types, but not all types in general. |
| // |
| namespace { |
| template <class BuiltinType, Type **Ty> |
| struct VISIBILITY_HIDDEN DirectIntRules |
| : public TemplateRules<ConstantInt, DirectIntRules<BuiltinType, Ty> > { |
| |
| static Constant *Add(const ConstantInt *V1, const ConstantInt *V2) { |
| BuiltinType R = (BuiltinType)V1->getZExtValue() + |
| (BuiltinType)V2->getZExtValue(); |
| return ConstantInt::get(*Ty, R); |
| } |
| |
| static Constant *Sub(const ConstantInt *V1, const ConstantInt *V2) { |
| BuiltinType R = (BuiltinType)V1->getZExtValue() - |
| (BuiltinType)V2->getZExtValue(); |
| return ConstantInt::get(*Ty, R); |
| } |
| |
| static Constant *Mul(const ConstantInt *V1, const ConstantInt *V2) { |
| BuiltinType R = (BuiltinType)V1->getZExtValue() * |
| (BuiltinType)V2->getZExtValue(); |
| return ConstantInt::get(*Ty, R); |
| } |
| |
| static Constant *LessThan(const ConstantInt *V1, const ConstantInt *V2) { |
| bool R = (BuiltinType)V1->getZExtValue() < (BuiltinType)V2->getZExtValue(); |
| return ConstantBool::get(R); |
| } |
| |
| static Constant *EqualTo(const ConstantInt *V1, const ConstantInt *V2) { |
| bool R = (BuiltinType)V1->getZExtValue() == (BuiltinType)V2->getZExtValue(); |
| return ConstantBool::get(R); |
| } |
| |
| static Constant *CastToPointer(const ConstantInt *V, |
| const PointerType *PTy) { |
| if (V->isNullValue()) // Is it a FP or Integral null value? |
| return ConstantPointerNull::get(PTy); |
| return 0; // Can't const prop other types of pointers |
| } |
| |
| // Casting operators. ick |
| #define DEF_CAST(TYPE, CLASS, CTYPE) \ |
| static Constant *CastTo##TYPE (const ConstantInt *V) { \ |
| return CLASS::get(Type::TYPE##Ty, (CTYPE)((BuiltinType)V->getZExtValue()));\ |
| } |
| |
| DEF_CAST(Bool , ConstantBool, bool) |
| DEF_CAST(SByte , ConstantInt, signed char) |
| DEF_CAST(UByte , ConstantInt, unsigned char) |
| DEF_CAST(Short , ConstantInt, signed short) |
| DEF_CAST(UShort, ConstantInt, unsigned short) |
| DEF_CAST(Int , ConstantInt, signed int) |
| DEF_CAST(UInt , ConstantInt, unsigned int) |
| DEF_CAST(Long , ConstantInt, int64_t) |
| DEF_CAST(ULong , ConstantInt, uint64_t) |
| DEF_CAST(Float , ConstantFP , float) |
| DEF_CAST(Double, ConstantFP , double) |
| #undef DEF_CAST |
| |
| static Constant *UDiv(const ConstantInt *V1, const ConstantInt *V2) { |
| if (V2->isNullValue()) // X / 0 |
| return 0; |
| BuiltinType R = (BuiltinType)(V1->getZExtValue() / V2->getZExtValue()); |
| return ConstantInt::get(*Ty, R); |
| } |
| |
| static Constant *SDiv(const ConstantInt *V1, const ConstantInt *V2) { |
| if (V2->isNullValue()) // X / 0 |
| return 0; |
| if (V2->isAllOnesValue() && // MIN_INT / -1 |
| (BuiltinType)V1->getSExtValue() == -(BuiltinType)V1->getSExtValue()) |
| return 0; |
| BuiltinType R = (BuiltinType)(V1->getSExtValue() / V2->getSExtValue()); |
| return ConstantInt::get(*Ty, R); |
| } |
| |
| static Constant *URem(const ConstantInt *V1, |
| const ConstantInt *V2) { |
| if (V2->isNullValue()) return 0; // X / 0 |
| BuiltinType R = (BuiltinType)(V1->getZExtValue() % V2->getZExtValue()); |
| return ConstantInt::get(*Ty, R); |
| } |
| |
| static Constant *SRem(const ConstantInt *V1, |
| const ConstantInt *V2) { |
| if (V2->isNullValue()) return 0; // X % 0 |
| if (V2->isAllOnesValue() && // MIN_INT % -1 |
| (BuiltinType)V1->getSExtValue() == -(BuiltinType)V1->getSExtValue()) |
| return 0; |
| BuiltinType R = (BuiltinType)(V1->getSExtValue() % V2->getSExtValue()); |
| return ConstantInt::get(*Ty, R); |
| } |
| |
| static Constant *And(const ConstantInt *V1, const ConstantInt *V2) { |
| BuiltinType R = |
| (BuiltinType)V1->getZExtValue() & (BuiltinType)V2->getZExtValue(); |
| return ConstantInt::get(*Ty, R); |
| } |
| static Constant *Or(const ConstantInt *V1, const ConstantInt *V2) { |
| BuiltinType R = |
| (BuiltinType)V1->getZExtValue() | (BuiltinType)V2->getZExtValue(); |
| return ConstantInt::get(*Ty, R); |
| } |
| static Constant *Xor(const ConstantInt *V1, const ConstantInt *V2) { |
| BuiltinType R = |
| (BuiltinType)V1->getZExtValue() ^ (BuiltinType)V2->getZExtValue(); |
| return ConstantInt::get(*Ty, R); |
| } |
| |
| static Constant *Shl(const ConstantInt *V1, const ConstantInt *V2) { |
| BuiltinType R = |
| (BuiltinType)V1->getZExtValue() << (BuiltinType)V2->getZExtValue(); |
| return ConstantInt::get(*Ty, R); |
| } |
| |
| static Constant *LShr(const ConstantInt *V1, const ConstantInt *V2) { |
| BuiltinType R = BuiltinType(V1->getZExtValue() >> V2->getZExtValue()); |
| return ConstantInt::get(*Ty, R); |
| } |
| |
| static Constant *AShr(const ConstantInt *V1, const ConstantInt *V2) { |
| BuiltinType R = BuiltinType(V1->getSExtValue() >> V2->getZExtValue()); |
| return ConstantInt::get(*Ty, R); |
| } |
| }; |
| } // end anonymous namespace |
| |
| |
| //===----------------------------------------------------------------------===// |
| // DirectFPRules Class |
| //===----------------------------------------------------------------------===// |
| // |
| /// DirectFPRules provides implementations of functions that are valid on |
| /// floating point types, but not all types in general. |
| /// |
| namespace { |
| template <class BuiltinType, Type **Ty> |
| struct VISIBILITY_HIDDEN DirectFPRules |
| : public TemplateRules<ConstantFP, DirectFPRules<BuiltinType, Ty> > { |
| |
| static Constant *Add(const ConstantFP *V1, const ConstantFP *V2) { |
| BuiltinType R = (BuiltinType)V1->getValue() + |
| (BuiltinType)V2->getValue(); |
| return ConstantFP::get(*Ty, R); |
| } |
| |
| static Constant *Sub(const ConstantFP *V1, const ConstantFP *V2) { |
| BuiltinType R = (BuiltinType)V1->getValue() - (BuiltinType)V2->getValue(); |
| return ConstantFP::get(*Ty, R); |
| } |
| |
| static Constant *Mul(const ConstantFP *V1, const ConstantFP *V2) { |
| BuiltinType R = (BuiltinType)V1->getValue() * (BuiltinType)V2->getValue(); |
| return ConstantFP::get(*Ty, R); |
| } |
| |
| static Constant *LessThan(const ConstantFP *V1, const ConstantFP *V2) { |
| bool R = (BuiltinType)V1->getValue() < (BuiltinType)V2->getValue(); |
| return ConstantBool::get(R); |
| } |
| |
| static Constant *EqualTo(const ConstantFP *V1, const ConstantFP *V2) { |
| bool R = (BuiltinType)V1->getValue() == (BuiltinType)V2->getValue(); |
| return ConstantBool::get(R); |
| } |
| |
| static Constant *CastToPointer(const ConstantFP *V, |
| const PointerType *PTy) { |
| if (V->isNullValue()) // Is it a FP or Integral null value? |
| return ConstantPointerNull::get(PTy); |
| return 0; // Can't const prop other types of pointers |
| } |
| |
| // Casting operators. ick |
| #define DEF_CAST(TYPE, CLASS, CTYPE) \ |
| static Constant *CastTo##TYPE (const ConstantFP *V) { \ |
| return CLASS::get(Type::TYPE##Ty, (CTYPE)(BuiltinType)V->getValue()); \ |
| } |
| |
| DEF_CAST(Bool , ConstantBool, bool) |
| DEF_CAST(SByte , ConstantInt, signed char) |
| DEF_CAST(UByte , ConstantInt, unsigned char) |
| DEF_CAST(Short , ConstantInt, signed short) |
| DEF_CAST(UShort, ConstantInt, unsigned short) |
| DEF_CAST(Int , ConstantInt, signed int) |
| DEF_CAST(UInt , ConstantInt, unsigned int) |
| DEF_CAST(Long , ConstantInt, int64_t) |
| DEF_CAST(ULong , ConstantInt, uint64_t) |
| DEF_CAST(Float , ConstantFP , float) |
| DEF_CAST(Double, ConstantFP , double) |
| #undef DEF_CAST |
| |
| static Constant *FRem(const ConstantFP *V1, const ConstantFP *V2) { |
| if (V2->isNullValue()) return 0; |
| BuiltinType Result = std::fmod((BuiltinType)V1->getValue(), |
| (BuiltinType)V2->getValue()); |
| return ConstantFP::get(*Ty, Result); |
| } |
| static Constant *FDiv(const ConstantFP *V1, const ConstantFP *V2) { |
| BuiltinType inf = std::numeric_limits<BuiltinType>::infinity(); |
| if (V2->isExactlyValue(0.0)) return ConstantFP::get(*Ty, inf); |
| if (V2->isExactlyValue(-0.0)) return ConstantFP::get(*Ty, -inf); |
| BuiltinType R = (BuiltinType)V1->getValue() / (BuiltinType)V2->getValue(); |
| return ConstantFP::get(*Ty, R); |
| } |
| }; |
| } // end anonymous namespace |
| |
| static ManagedStatic<EmptyRules> EmptyR; |
| static ManagedStatic<BoolRules> BoolR; |
| static ManagedStatic<NullPointerRules> NullPointerR; |
| static ManagedStatic<ConstantPackedRules> ConstantPackedR; |
| static ManagedStatic<GeneralPackedRules> GeneralPackedR; |
| static ManagedStatic<DirectIntRules<signed char , &Type::SByteTy> > SByteR; |
| static ManagedStatic<DirectIntRules<unsigned char , &Type::UByteTy> > UByteR; |
| static ManagedStatic<DirectIntRules<signed short , &Type::ShortTy> > ShortR; |
| static ManagedStatic<DirectIntRules<unsigned short, &Type::UShortTy> > UShortR; |
| static ManagedStatic<DirectIntRules<signed int , &Type::IntTy> > IntR; |
| static ManagedStatic<DirectIntRules<unsigned int , &Type::UIntTy> > UIntR; |
| static ManagedStatic<DirectIntRules<int64_t , &Type::LongTy> > LongR; |
| static ManagedStatic<DirectIntRules<uint64_t , &Type::ULongTy> > ULongR; |
| static ManagedStatic<DirectFPRules <float , &Type::FloatTy> > FloatR; |
| static ManagedStatic<DirectFPRules <double , &Type::DoubleTy> > DoubleR; |
| |
| /// ConstRules::get - This method returns the constant rules implementation that |
| /// implements the semantics of the two specified constants. |
| ConstRules &ConstRules::get(const Constant *V1, const Constant *V2) { |
| if (isa<ConstantExpr>(V1) || isa<ConstantExpr>(V2) || |
| isa<GlobalValue>(V1) || isa<GlobalValue>(V2) || |
| isa<UndefValue>(V1) || isa<UndefValue>(V2)) |
| return *EmptyR; |
| |
| switch (V1->getType()->getTypeID()) { |
| default: assert(0 && "Unknown value type for constant folding!"); |
| case Type::BoolTyID: return *BoolR; |
| case Type::PointerTyID: return *NullPointerR; |
| case Type::SByteTyID: return *SByteR; |
| case Type::UByteTyID: return *UByteR; |
| case Type::ShortTyID: return *ShortR; |
| case Type::UShortTyID: return *UShortR; |
| case Type::IntTyID: return *IntR; |
| case Type::UIntTyID: return *UIntR; |
| case Type::LongTyID: return *LongR; |
| case Type::ULongTyID: return *ULongR; |
| case Type::FloatTyID: return *FloatR; |
| case Type::DoubleTyID: return *DoubleR; |
| case Type::PackedTyID: |
| if (isa<ConstantPacked>(V1) && isa<ConstantPacked>(V2)) |
| return *ConstantPackedR; |
| return *GeneralPackedR; // Constant folding rules for ConstantAggregateZero. |
| } |
| } |
| |
| |
| //===----------------------------------------------------------------------===// |
| // ConstantFold*Instruction Implementations |
| //===----------------------------------------------------------------------===// |
| |
| /// CastConstantPacked - Convert the specified ConstantPacked node to the |
| /// specified packed type. At this point, we know that the elements of the |
| /// input packed constant are all simple integer or FP values. |
| static Constant *CastConstantPacked(ConstantPacked *CP, |
| const PackedType *DstTy) { |
| unsigned SrcNumElts = CP->getType()->getNumElements(); |
| unsigned DstNumElts = DstTy->getNumElements(); |
| const Type *SrcEltTy = CP->getType()->getElementType(); |
| const Type *DstEltTy = DstTy->getElementType(); |
| |
| // If both vectors have the same number of elements (thus, the elements |
| // are the same size), perform the conversion now. |
| if (SrcNumElts == DstNumElts) { |
| std::vector<Constant*> Result; |
| |
| // If the src and dest elements are both integers, or both floats, we can |
| // just BitCast each element because the elements are the same size. |
| if ((SrcEltTy->isIntegral() && DstEltTy->isIntegral()) || |
| (SrcEltTy->isFloatingPoint() && DstEltTy->isFloatingPoint())) { |
| for (unsigned i = 0; i != SrcNumElts; ++i) |
| Result.push_back( |
| ConstantExpr::getCast(Instruction::BitCast, CP->getOperand(1), |
| DstEltTy)); |
| return ConstantPacked::get(Result); |
| } |
| |
| // If this is an int-to-fp cast .. |
| if (SrcEltTy->isIntegral()) { |
| // Ensure that it is int-to-fp cast |
| assert(DstEltTy->isFloatingPoint()); |
| if (DstEltTy->getTypeID() == Type::DoubleTyID) { |
| for (unsigned i = 0; i != SrcNumElts; ++i) { |
| double V = |
| BitsToDouble(cast<ConstantInt>(CP->getOperand(i))->getZExtValue()); |
| Result.push_back(ConstantFP::get(Type::DoubleTy, V)); |
| } |
| return ConstantPacked::get(Result); |
| } |
| assert(DstEltTy == Type::FloatTy && "Unknown fp type!"); |
| for (unsigned i = 0; i != SrcNumElts; ++i) { |
| float V = |
| BitsToFloat(cast<ConstantInt>(CP->getOperand(i))->getZExtValue()); |
| Result.push_back(ConstantFP::get(Type::FloatTy, V)); |
| } |
| return ConstantPacked::get(Result); |
| } |
| |
| // Otherwise, this is an fp-to-int cast. |
| assert(SrcEltTy->isFloatingPoint() && DstEltTy->isIntegral()); |
| |
| if (SrcEltTy->getTypeID() == Type::DoubleTyID) { |
| for (unsigned i = 0; i != SrcNumElts; ++i) { |
| uint64_t V = |
| DoubleToBits(cast<ConstantFP>(CP->getOperand(i))->getValue()); |
| Constant *C = ConstantInt::get(Type::ULongTy, V); |
| Result.push_back(ConstantExpr::getCast(C, DstEltTy)); |
| } |
| return ConstantPacked::get(Result); |
| } |
| |
| assert(SrcEltTy->getTypeID() == Type::FloatTyID); |
| for (unsigned i = 0; i != SrcNumElts; ++i) { |
| uint32_t V = FloatToBits(cast<ConstantFP>(CP->getOperand(i))->getValue()); |
| Constant *C = ConstantInt::get(Type::UIntTy, V); |
| Result.push_back(ConstantExpr::getCast(C, DstEltTy)); |
| } |
| return ConstantPacked::get(Result); |
| } |
| |
| // Otherwise, this is a cast that changes element count and size. Handle |
| // casts which shrink the elements here. |
| |
| // FIXME: We need to know endianness to do this! |
| |
| return 0; |
| } |
| |
| /// This function determines which opcode to use to fold two constant cast |
| /// expressions together. It uses CastInst::isEliminableCastPair to determine |
| /// the opcode. Consequently its just a wrapper around that function. |
| /// @Determine if it is valid to fold a cast of a cast |
| static unsigned |
| foldConstantCastPair( |
| unsigned opc, ///< opcode of the second cast constant expression |
| const ConstantExpr*Op, ///< the first cast constant expression |
| const Type *DstTy ///< desintation type of the first cast |
| ) { |
| assert(Op && Op->isCast() && "Can't fold cast of cast without a cast!"); |
| assert(DstTy && DstTy->isFirstClassType() && "Invalid cast destination type"); |
| assert(CastInst::isCast(opc) && "Invalid cast opcode"); |
| |
| // The the types and opcodes for the two Cast constant expressions |
| const Type *SrcTy = Op->getOperand(0)->getType(); |
| const Type *MidTy = Op->getType(); |
| Instruction::CastOps firstOp = Instruction::CastOps(Op->getOpcode()); |
| Instruction::CastOps secondOp = Instruction::CastOps(opc); |
| |
| // Let CastInst::isEliminableCastPair do the heavy lifting. |
| return CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy, DstTy, |
| Type::ULongTy); |
| } |
| |
| Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V, |
| const Type *DestTy) { |
| const Type *SrcTy = V->getType(); |
| |
| // Handle some simple cases |
| if (SrcTy == DestTy) |
| return (Constant*)V; // no-op cast |
| |
| if (isa<UndefValue>(V)) |
| return UndefValue::get(DestTy); |
| |
| // If the cast operand is a constant expression, there's a few things we can |
| // do to try to simplify it. |
| if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) { |
| if (CE->isCast()) { |
| // Try hard to fold cast of cast because they are almost always |
| // eliminable. |
| if (unsigned newOpc = foldConstantCastPair(opc, CE, DestTy)) |
| return ConstantExpr::getCast(newOpc, CE->getOperand(0), DestTy); |
| } else if (CE->getOpcode() == Instruction::GetElementPtr) { |
| // If all of the indexes in the GEP are null values, there is no pointer |
| // adjustment going on. We might as well cast the source pointer. |
| bool isAllNull = true; |
| for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i) |
| if (!CE->getOperand(i)->isNullValue()) { |
| isAllNull = false; |
| break; |
| } |
| if (isAllNull) |
| return ConstantExpr::getCast(CE->getOperand(0), DestTy); |
| } |
| } |
| |
| // We actually have to do a cast now, but first, we might need to fix up |
| // the value of the operand. |
| switch (opc) { |
| case Instruction::FPTrunc: |
| case Instruction::Trunc: |
| case Instruction::FPExt: |
| break; // floating point input & output, no fixup needed |
| case Instruction::FPToUI: { |
| ConstRules &Rules = ConstRules::get(V, V); |
| V = Rules.castToULong(V); // make sure we get an unsigned value first |
| break; |
| } |
| case Instruction::FPToSI: { |
| ConstRules &Rules = ConstRules::get(V, V); |
| V = Rules.castToLong(V); // make sure we get a signed value first |
| break; |
| } |
| case Instruction::IntToPtr: //always treated as unsigned |
| case Instruction::UIToFP: |
| case Instruction::ZExt: |
| // A ZExt always produces an unsigned value so we need to cast the value |
| // now before we try to cast it to the destination type |
| if (isa<ConstantInt>(V)) |
| V = ConstantInt::get(SrcTy->getUnsignedVersion(), |
| cast<ConstantIntegral>(V)->getZExtValue()); |
| break; |
| case Instruction::SIToFP: |
| case Instruction::SExt: |
| // A SExt always produces a signed value so we need to cast the value |
| // now before we try to cast it to the destiniation type. |
| if (isa<ConstantInt>(V)) |
| V = ConstantInt::get(SrcTy->getSignedVersion(), |
| cast<ConstantIntegral>(V)->getSExtValue()); |
| break; |
| |
| case Instruction::PtrToInt: |
| // Cast of a global address to boolean is always true. |
| if (isa<GlobalValue>(V)) { |
| if (DestTy == Type::BoolTy) |
| // FIXME: When we support 'external weak' references, we have to |
| // prevent this transformation from happening. This code will need |
| // to be updated to ignore external weak symbols when we support it. |
| return ConstantBool::getTrue(); |
| } |
| break; |
| case Instruction::BitCast: |
| // Check to see if we are casting a pointer to an aggregate to a pointer to |
| // the first element. If so, return the appropriate GEP instruction. |
| if (const PointerType *PTy = dyn_cast<PointerType>(V->getType())) |
| if (const PointerType *DPTy = dyn_cast<PointerType>(DestTy)) { |
| std::vector<Value*> IdxList; |
| IdxList.push_back(Constant::getNullValue(Type::IntTy)); |
| const Type *ElTy = PTy->getElementType(); |
| while (ElTy != DPTy->getElementType()) { |
| if (const StructType *STy = dyn_cast<StructType>(ElTy)) { |
| if (STy->getNumElements() == 0) break; |
| ElTy = STy->getElementType(0); |
| IdxList.push_back(Constant::getNullValue(Type::UIntTy)); |
| } else if (const SequentialType *STy = |
| dyn_cast<SequentialType>(ElTy)) { |
| if (isa<PointerType>(ElTy)) break; // Can't index into pointers! |
| ElTy = STy->getElementType(); |
| IdxList.push_back(IdxList[0]); |
| } else { |
| break; |
| } |
| } |
| |
| if (ElTy == DPTy->getElementType()) |
| return ConstantExpr::getGetElementPtr( |
| const_cast<Constant*>(V),IdxList); |
| } |
| |
| // Handle casts from one packed constant to another. We know that the src |
| // and dest type have the same size (otherwise its an illegal cast). |
| if (const PackedType *DestPTy = dyn_cast<PackedType>(DestTy)) { |
| if (const PackedType *SrcTy = dyn_cast<PackedType>(V->getType())) { |
| assert(DestPTy->getBitWidth() == SrcTy->getBitWidth() && |
| "Not cast between same sized vectors!"); |
| // First, check for null and undef |
| if (isa<ConstantAggregateZero>(V)) |
| return Constant::getNullValue(DestTy); |
| if (isa<UndefValue>(V)) |
| return UndefValue::get(DestTy); |
| |
| if (const ConstantPacked *CP = dyn_cast<ConstantPacked>(V)) { |
| // This is a cast from a ConstantPacked of one type to a |
| // ConstantPacked of another type. Check to see if all elements of |
| // the input are simple. |
| bool AllSimpleConstants = true; |
| for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) { |
| if (!isa<ConstantInt>(CP->getOperand(i)) && |
| !isa<ConstantFP>(CP->getOperand(i))) { |
| AllSimpleConstants = false; |
| break; |
| } |
| } |
| |
| // If all of the elements are simple constants, we can fold this. |
| if (AllSimpleConstants) |
| return CastConstantPacked(const_cast<ConstantPacked*>(CP), DestPTy); |
| } |
| } |
| } |
| |
| // Handle sign conversion for integer no-op casts. We need to cast the |
| // value to the correct signedness before we try to cast it to the |
| // destination type. Be careful to do this only for integer types. |
| if (isa<ConstantIntegral>(V) && SrcTy->isInteger()) { |
| if (SrcTy->isSigned()) |
| V = ConstantInt::get(SrcTy->getUnsignedVersion(), |
| cast<ConstantIntegral>(V)->getZExtValue()); |
| else |
| V = ConstantInt::get(SrcTy->getSignedVersion(), |
| cast<ConstantIntegral>(V)->getSExtValue()); |
| } |
| break; |
| default: |
| assert(!"Invalid CE CastInst opcode"); |
| break; |
| } |
| |
| // Okay, no more folding possible, time to cast |
| ConstRules &Rules = ConstRules::get(V, V); |
| switch (DestTy->getTypeID()) { |
| case Type::BoolTyID: return Rules.castToBool(V); |
| case Type::UByteTyID: return Rules.castToUByte(V); |
| case Type::SByteTyID: return Rules.castToSByte(V); |
| case Type::UShortTyID: return Rules.castToUShort(V); |
| case Type::ShortTyID: return Rules.castToShort(V); |
| case Type::UIntTyID: return Rules.castToUInt(V); |
| case Type::IntTyID: return Rules.castToInt(V); |
| case Type::ULongTyID: return Rules.castToULong(V); |
| case Type::LongTyID: return Rules.castToLong(V); |
| case Type::FloatTyID: return Rules.castToFloat(V); |
| case Type::DoubleTyID: return Rules.castToDouble(V); |
| case Type::PointerTyID: |
| return Rules.castToPointer(V, cast<PointerType>(DestTy)); |
| // what about packed ? |
| default: return 0; |
| } |
| } |
| |
| Constant *llvm::ConstantFoldSelectInstruction(const Constant *Cond, |
| const Constant *V1, |
| const Constant *V2) { |
| if (const ConstantBool *CB = dyn_cast<ConstantBool>(Cond)) |
| return const_cast<Constant*>(CB->getValue() ? V1 : V2); |
| |
| if (isa<UndefValue>(V1)) return const_cast<Constant*>(V2); |
| if (isa<UndefValue>(V2)) return const_cast<Constant*>(V1); |
| if (isa<UndefValue>(Cond)) return const_cast<Constant*>(V1); |
| if (V1 == V2) return const_cast<Constant*>(V1); |
| return 0; |
| } |
| |
| Constant *llvm::ConstantFoldExtractElementInstruction(const Constant *Val, |
| const Constant *Idx) { |
| if (isa<UndefValue>(Val)) // ee(undef, x) -> undef |
| return UndefValue::get(cast<PackedType>(Val->getType())->getElementType()); |
| if (Val->isNullValue()) // ee(zero, x) -> zero |
| return Constant::getNullValue( |
| cast<PackedType>(Val->getType())->getElementType()); |
| |
| if (const ConstantPacked *CVal = dyn_cast<ConstantPacked>(Val)) { |
| if (const ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx)) { |
| return const_cast<Constant*>(CVal->getOperand(CIdx->getZExtValue())); |
| } else if (isa<UndefValue>(Idx)) { |
| // ee({w,x,y,z}, undef) -> w (an arbitrary value). |
| return const_cast<Constant*>(CVal->getOperand(0)); |
| } |
| } |
| return 0; |
| } |
| |
| Constant *llvm::ConstantFoldInsertElementInstruction(const Constant *Val, |
| const Constant *Elt, |
| const Constant *Idx) { |
| const ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx); |
| if (!CIdx) return 0; |
| uint64_t idxVal = CIdx->getZExtValue(); |
| if (isa<UndefValue>(Val)) { |
| // Insertion of scalar constant into packed undef |
| // Optimize away insertion of undef |
| if (isa<UndefValue>(Elt)) |
| return const_cast<Constant*>(Val); |
| // Otherwise break the aggregate undef into multiple undefs and do |
| // the insertion |
| unsigned numOps = |
| cast<PackedType>(Val->getType())->getNumElements(); |
| std::vector<Constant*> Ops; |
| Ops.reserve(numOps); |
| for (unsigned i = 0; i < numOps; ++i) { |
| const Constant *Op = |
| (i == idxVal) ? Elt : UndefValue::get(Elt->getType()); |
| Ops.push_back(const_cast<Constant*>(Op)); |
| } |
| return ConstantPacked::get(Ops); |
| } |
| if (isa<ConstantAggregateZero>(Val)) { |
| // Insertion of scalar constant into packed aggregate zero |
| // Optimize away insertion of zero |
| if (Elt->isNullValue()) |
| return const_cast<Constant*>(Val); |
| // Otherwise break the aggregate zero into multiple zeros and do |
| // the insertion |
| unsigned numOps = |
| cast<PackedType>(Val->getType())->getNumElements(); |
| std::vector<Constant*> Ops; |
| Ops.reserve(numOps); |
| for (unsigned i = 0; i < numOps; ++i) { |
| const Constant *Op = |
| (i == idxVal) ? Elt : Constant::getNullValue(Elt->getType()); |
| Ops.push_back(const_cast<Constant*>(Op)); |
| } |
| return ConstantPacked::get(Ops); |
| } |
| if (const ConstantPacked *CVal = dyn_cast<ConstantPacked>(Val)) { |
| // Insertion of scalar constant into packed constant |
| std::vector<Constant*> Ops; |
| Ops.reserve(CVal->getNumOperands()); |
| for (unsigned i = 0; i < CVal->getNumOperands(); ++i) { |
| const Constant *Op = |
| (i == idxVal) ? Elt : cast<Constant>(CVal->getOperand(i)); |
| Ops.push_back(const_cast<Constant*>(Op)); |
| } |
| return ConstantPacked::get(Ops); |
| } |
| return 0; |
| } |
| |
| Constant *llvm::ConstantFoldShuffleVectorInstruction(const Constant *V1, |
| const Constant *V2, |
| const Constant *Mask) { |
| // TODO: |
| return 0; |
| } |
| |
| |
| /// isZeroSizedType - This type is zero sized if its an array or structure of |
| /// zero sized types. The only leaf zero sized type is an empty structure. |
| static bool isMaybeZeroSizedType(const Type *Ty) { |
| if (isa<OpaqueType>(Ty)) return true; // Can't say. |
| if (const StructType *STy = dyn_cast<StructType>(Ty)) { |
| |
| // If all of elements have zero size, this does too. |
| for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) |
| if (!isMaybeZeroSizedType(STy->getElementType(i))) return false; |
| return true; |
| |
| } else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) { |
| return isMaybeZeroSizedType(ATy->getElementType()); |
| } |
| return false; |
| } |
| |
| /// IdxCompare - Compare the two constants as though they were getelementptr |
| /// indices. This allows coersion of the types to be the same thing. |
| /// |
| /// If the two constants are the "same" (after coersion), return 0. If the |
| /// first is less than the second, return -1, if the second is less than the |
| /// first, return 1. If the constants are not integral, return -2. |
| /// |
| static int IdxCompare(Constant *C1, Constant *C2, const Type *ElTy) { |
| if (C1 == C2) return 0; |
| |
| // Ok, we found a different index. Are either of the operands ConstantExprs? |
| // If so, we can't do anything with them. |
| if (!isa<ConstantInt>(C1) || !isa<ConstantInt>(C2)) |
| return -2; // don't know! |
| |
| // Ok, we have two differing integer indices. Sign extend them to be the same |
| // type. Long is always big enough, so we use it. |
| if (C1->getType() != Type::LongTy && C1->getType() != Type::ULongTy) |
| C1 = ConstantExpr::getSignExtend(C1, Type::LongTy); |
| else |
| C1 = ConstantExpr::getBitCast(C1, Type::LongTy); |
| if (C2->getType() != Type::LongTy && C1->getType() != Type::ULongTy) |
| C2 = ConstantExpr::getSignExtend(C2, Type::LongTy); |
| else |
| C2 = ConstantExpr::getBitCast(C2, Type::LongTy); |
| |
| if (C1 == C2) return 0; // Are they just differing types? |
| |
| // If the type being indexed over is really just a zero sized type, there is |
| // no pointer difference being made here. |
| if (isMaybeZeroSizedType(ElTy)) |
| return -2; // dunno. |
| |
| // If they are really different, now that they are the same type, then we |
| // found a difference! |
| if (cast<ConstantInt>(C1)->getSExtValue() < |
| cast<ConstantInt>(C2)->getSExtValue()) |
| return -1; |
| else |
| return 1; |
| } |
| |
| /// evaluateRelation - This function determines if there is anything we can |
| /// decide about the two constants provided. This doesn't need to handle simple |
| /// things like integer comparisons, but should instead handle ConstantExprs |
| /// and GlobalValuess. If we can determine that the two constants have a |
| /// particular relation to each other, we should return the corresponding SetCC |
| /// code, otherwise return Instruction::BinaryOpsEnd. |
| /// |
| /// To simplify this code we canonicalize the relation so that the first |
| /// operand is always the most "complex" of the two. We consider simple |
| /// constants (like ConstantInt) to be the simplest, followed by |
| /// GlobalValues, followed by ConstantExpr's (the most complex). |
| /// |
| static Instruction::BinaryOps evaluateRelation(Constant *V1, Constant *V2) { |
| assert(V1->getType() == V2->getType() && |
| "Cannot compare different types of values!"); |
| if (V1 == V2) return Instruction::SetEQ; |
| |
| if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1)) { |
| if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2)) { |
| // We distilled this down to a simple case, use the standard constant |
| // folder. |
| ConstantBool *R = dyn_cast<ConstantBool>(ConstantExpr::getSetEQ(V1, V2)); |
| if (R && R->getValue()) return Instruction::SetEQ; |
| R = dyn_cast<ConstantBool>(ConstantExpr::getSetLT(V1, V2)); |
| if (R && R->getValue()) return Instruction::SetLT; |
| R = dyn_cast<ConstantBool>(ConstantExpr::getSetGT(V1, V2)); |
| if (R && R->getValue()) return Instruction::SetGT; |
| |
| // If we couldn't figure it out, bail. |
| return Instruction::BinaryOpsEnd; |
| } |
| |
| // If the first operand is simple, swap operands. |
| Instruction::BinaryOps SwappedRelation = evaluateRelation(V2, V1); |
| if (SwappedRelation != Instruction::BinaryOpsEnd) |
| return SetCondInst::getSwappedCondition(SwappedRelation); |
| |
| } else if (const GlobalValue *CPR1 = dyn_cast<GlobalValue>(V1)) { |
| if (isa<ConstantExpr>(V2)) { // Swap as necessary. |
| Instruction::BinaryOps SwappedRelation = evaluateRelation(V2, V1); |
| if (SwappedRelation != Instruction::BinaryOpsEnd) |
| return SetCondInst::getSwappedCondition(SwappedRelation); |
| else |
| return Instruction::BinaryOpsEnd; |
| } |
| |
| // Now we know that the RHS is a GlobalValue or simple constant, |
| // which (since the types must match) means that it's a ConstantPointerNull. |
| if (const GlobalValue *CPR2 = dyn_cast<GlobalValue>(V2)) { |
| assert(CPR1 != CPR2 && |
| "GVs for the same value exist at different addresses??"); |
| // FIXME: If both globals are external weak, they might both be null! |
| return Instruction::SetNE; |
| } else { |
| assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!"); |
| // Global can never be null. FIXME: if we implement external weak |
| // linkage, this is not necessarily true! |
| return Instruction::SetNE; |
| } |
| |
| } else { |
| // Ok, the LHS is known to be a constantexpr. The RHS can be any of a |
| // constantexpr, a CPR, or a simple constant. |
| ConstantExpr *CE1 = cast<ConstantExpr>(V1); |
| Constant *CE1Op0 = CE1->getOperand(0); |
| |
| switch (CE1->getOpcode()) { |
| case Instruction::Trunc: |
| case Instruction::FPTrunc: |
| case Instruction::FPExt: |
| case Instruction::FPToUI: |
| case Instruction::FPToSI: |
| break; // We don't do anything with floating point. |
| case Instruction::ZExt: |
| case Instruction::SExt: |
| case Instruction::UIToFP: |
| case Instruction::SIToFP: |
| case Instruction::PtrToInt: |
| case Instruction::IntToPtr: |
| case Instruction::BitCast: |
| // If the cast is not actually changing bits, and the second operand is a |
| // null pointer, do the comparison with the pre-casted value. |
| if (V2->isNullValue() && |
| (isa<PointerType>(CE1->getType()) || CE1->getType()->isIntegral())) |
| return evaluateRelation(CE1Op0, |
| Constant::getNullValue(CE1Op0->getType())); |
| |
| // If the dest type is a pointer type, and the RHS is a constantexpr cast |
| // from the same type as the src of the LHS, evaluate the inputs. This is |
| // important for things like "seteq (cast 4 to int*), (cast 5 to int*)", |
| // which happens a lot in compilers with tagged integers. |
| if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(V2)) |
| if (isa<PointerType>(CE1->getType()) && CE2->isCast() && |
| CE1->getOperand(0)->getType() == CE2->getOperand(0)->getType() && |
| CE1->getOperand(0)->getType()->isIntegral()) { |
| return evaluateRelation(CE1->getOperand(0), CE2->getOperand(0)); |
| } |
| break; |
| |
| case Instruction::GetElementPtr: |
| // Ok, since this is a getelementptr, we know that the constant has a |
| // pointer type. Check the various cases. |
| if (isa<ConstantPointerNull>(V2)) { |
| // If we are comparing a GEP to a null pointer, check to see if the base |
| // of the GEP equals the null pointer. |
| if (isa<GlobalValue>(CE1Op0)) { |
| // FIXME: this is not true when we have external weak references! |
| // No offset can go from a global to a null pointer. |
| return Instruction::SetGT; |
| } else if (isa<ConstantPointerNull>(CE1Op0)) { |
| // If we are indexing from a null pointer, check to see if we have any |
| // non-zero indices. |
| for (unsigned i = 1, e = CE1->getNumOperands(); i != e; ++i) |
| if (!CE1->getOperand(i)->isNullValue()) |
| // Offsetting from null, must not be equal. |
| return Instruction::SetGT; |
| // Only zero indexes from null, must still be zero. |
| return Instruction::SetEQ; |
| } |
| // Otherwise, we can't really say if the first operand is null or not. |
| } else if (const GlobalValue *CPR2 = dyn_cast<GlobalValue>(V2)) { |
| if (isa<ConstantPointerNull>(CE1Op0)) { |
| // FIXME: This is not true with external weak references. |
| return Instruction::SetLT; |
| } else if (const GlobalValue *CPR1 = dyn_cast<GlobalValue>(CE1Op0)) { |
| if (CPR1 == CPR2) { |
| // If this is a getelementptr of the same global, then it must be |
| // different. Because the types must match, the getelementptr could |
| // only have at most one index, and because we fold getelementptr's |
| // with a single zero index, it must be nonzero. |
| assert(CE1->getNumOperands() == 2 && |
| !CE1->getOperand(1)->isNullValue() && |
| "Suprising getelementptr!"); |
| return Instruction::SetGT; |
| } else { |
| // If they are different globals, we don't know what the value is, |
| // but they can't be equal. |
| return Instruction::SetNE; |
| } |
| } |
| } else { |
| const ConstantExpr *CE2 = cast<ConstantExpr>(V2); |
| const Constant *CE2Op0 = CE2->getOperand(0); |
| |
| // There are MANY other foldings that we could perform here. They will |
| // probably be added on demand, as they seem needed. |
| switch (CE2->getOpcode()) { |
| default: break; |
| case Instruction::GetElementPtr: |
| // By far the most common case to handle is when the base pointers are |
| // obviously to the same or different globals. |
| if (isa<GlobalValue>(CE1Op0) && isa<GlobalValue>(CE2Op0)) { |
| if (CE1Op0 != CE2Op0) // Don't know relative ordering, but not equal |
| return Instruction::SetNE; |
| // Ok, we know that both getelementptr instructions are based on the |
| // same global. From this, we can precisely determine the relative |
| // ordering of the resultant pointers. |
| unsigned i = 1; |
| |
| // Compare all of the operands the GEP's have in common. |
| gep_type_iterator GTI = gep_type_begin(CE1); |
| for (;i != CE1->getNumOperands() && i != CE2->getNumOperands(); |
| ++i, ++GTI) |
| switch (IdxCompare(CE1->getOperand(i), CE2->getOperand(i), |
| GTI.getIndexedType())) { |
| case -1: return Instruction::SetLT; |
| case 1: return Instruction::SetGT; |
| case -2: return Instruction::BinaryOpsEnd; |
| } |
| |
| // Ok, we ran out of things they have in common. If any leftovers |
| // are non-zero then we have a difference, otherwise we are equal. |
| for (; i < CE1->getNumOperands(); ++i) |
| if (!CE1->getOperand(i)->isNullValue()) |
| if (isa<ConstantIntegral>(CE1->getOperand(i))) |
| return Instruction::SetGT; |
| else |
| return Instruction::BinaryOpsEnd; // Might be equal. |
| |
| for (; i < CE2->getNumOperands(); ++i) |
| if (!CE2->getOperand(i)->isNullValue()) |
| if (isa<ConstantIntegral>(CE2->getOperand(i))) |
| return Instruction::SetLT; |
| else |
| return Instruction::BinaryOpsEnd; // Might be equal. |
| return Instruction::SetEQ; |
| } |
| } |
| } |
| |
| default: |
| break; |
| } |
| } |
| |
| return Instruction::BinaryOpsEnd; |
| } |
| |
| Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, |
| const Constant *V1, |
| const Constant *V2) { |
| Constant *C = 0; |
| switch (Opcode) { |
| default: break; |
| case Instruction::Add: C = ConstRules::get(V1, V2).add(V1, V2); break; |
| case Instruction::Sub: C = ConstRules::get(V1, V2).sub(V1, V2); break; |
| case Instruction::Mul: C = ConstRules::get(V1, V2).mul(V1, V2); break; |
| case Instruction::UDiv: C = ConstRules::get(V1, V2).udiv(V1, V2); break; |
| case Instruction::SDiv: C = ConstRules::get(V1, V2).sdiv(V1, V2); break; |
| case Instruction::FDiv: C = ConstRules::get(V1, V2).fdiv(V1, V2); break; |
| case Instruction::URem: C = ConstRules::get(V1, V2).urem(V1, V2); break; |
| case Instruction::SRem: C = ConstRules::get(V1, V2).srem(V1, V2); break; |
| case Instruction::FRem: C = ConstRules::get(V1, V2).frem(V1, V2); break; |
| case Instruction::And: C = ConstRules::get(V1, V2).op_and(V1, V2); break; |
| case Instruction::Or: C = ConstRules::get(V1, V2).op_or (V1, V2); break; |
| case Instruction::Xor: C = ConstRules::get(V1, V2).op_xor(V1, V2); break; |
| case Instruction::Shl: C = ConstRules::get(V1, V2).shl(V1, V2); break; |
| case Instruction::LShr: C = ConstRules::get(V1, V2).lshr(V1, V2); break; |
| case Instruction::AShr: C = ConstRules::get(V1, V2).ashr(V1, V2); break; |
| case Instruction::SetEQ: C = ConstRules::get(V1, V2).equalto(V1, V2); break; |
| case Instruction::SetLT: C = ConstRules::get(V1, V2).lessthan(V1, V2);break; |
| case Instruction::SetGT: C = ConstRules::get(V1, V2).lessthan(V2, V1);break; |
| case Instruction::SetNE: // V1 != V2 === !(V1 == V2) |
| C = ConstRules::get(V1, V2).equalto(V1, V2); |
| if (C) return ConstantExpr::getNot(C); |
| break; |
| case Instruction::SetLE: // V1 <= V2 === !(V2 < V1) |
| C = ConstRules::get(V1, V2).lessthan(V2, V1); |
| if (C) return ConstantExpr::getNot(C); |
| break; |
| case Instruction::SetGE: // V1 >= V2 === !(V1 < V2) |
| C = ConstRules::get(V1, V2).lessthan(V1, V2); |
| if (C) return ConstantExpr::getNot(C); |
| break; |
| } |
| |
| // If we successfully folded the expression, return it now. |
| if (C) return C; |
| |
| if (SetCondInst::isComparison(Opcode)) { |
| if (isa<UndefValue>(V1) || isa<UndefValue>(V2)) |
| return UndefValue::get(Type::BoolTy); |
| switch (evaluateRelation(const_cast<Constant*>(V1), |
| const_cast<Constant*>(V2))) { |
| default: assert(0 && "Unknown relational!"); |
| case Instruction::BinaryOpsEnd: |
| break; // Couldn't determine anything about these constants. |
| case Instruction::SetEQ: // We know the constants are equal! |
| // If we know the constants are equal, we can decide the result of this |
| // computation precisely. |
| return ConstantBool::get(Opcode == Instruction::SetEQ || |
| Opcode == Instruction::SetLE || |
| Opcode == Instruction::SetGE); |
| case Instruction::SetLT: |
| // If we know that V1 < V2, we can decide the result of this computation |
| // precisely. |
| return ConstantBool::get(Opcode == Instruction::SetLT || |
| Opcode == Instruction::SetNE || |
| Opcode == Instruction::SetLE); |
| case Instruction::SetGT: |
| // If we know that V1 > V2, we can decide the result of this computation |
| // precisely. |
| return ConstantBool::get(Opcode == Instruction::SetGT || |
| Opcode == Instruction::SetNE || |
| Opcode == Instruction::SetGE); |
| case Instruction::SetLE: |
| // If we know that V1 <= V2, we can only partially decide this relation. |
| if (Opcode == Instruction::SetGT) return ConstantBool::getFalse(); |
| if (Opcode == Instruction::SetLT) return ConstantBool::getTrue(); |
| break; |
| |
| case Instruction::SetGE: |
| // If we know that V1 >= V2, we can only partially decide this relation. |
| if (Opcode == Instruction::SetLT) return ConstantBool::getFalse(); |
| if (Opcode == Instruction::SetGT) return ConstantBool::getTrue(); |
| break; |
| |
| case Instruction::SetNE: |
| // If we know that V1 != V2, we can only partially decide this relation. |
| if (Opcode == Instruction::SetEQ) return ConstantBool::getFalse(); |
| if (Opcode == Instruction::SetNE) return ConstantBool::getTrue(); |
| break; |
| } |
| } |
| |
| if (isa<UndefValue>(V1) || isa<UndefValue>(V2)) { |
| switch (Opcode) { |
| case Instruction::Add: |
| case Instruction::Sub: |
| case Instruction::Xor: |
| return UndefValue::get(V1->getType()); |
| |
| case Instruction::Mul: |
| case Instruction::And: |
| return Constant::getNullValue(V1->getType()); |
| case Instruction::UDiv: |
| case Instruction::SDiv: |
| case Instruction::FDiv: |
| case Instruction::URem: |
| case Instruction::SRem: |
| case Instruction::FRem: |
| if (!isa<UndefValue>(V2)) // undef / X -> 0 |
| return Constant::getNullValue(V1->getType()); |
| return const_cast<Constant*>(V2); // X / undef -> undef |
| case Instruction::Or: // X | undef -> -1 |
| return ConstantInt::getAllOnesValue(V1->getType()); |
| case Instruction::LShr: |
| if (isa<UndefValue>(V2) && isa<UndefValue>(V1)) |
| return const_cast<Constant*>(V1); // undef lshr undef -> undef |
| return Constant::getNullValue(V1->getType()); // X lshr undef -> 0 |
| // undef lshr X -> 0 |
| case Instruction::AShr: |
| if (!isa<UndefValue>(V2)) |
| return const_cast<Constant*>(V1); // undef ashr X --> undef |
| else if (isa<UndefValue>(V1)) |
| return const_cast<Constant*>(V1); // undef ashr undef -> undef |
| else |
| return const_cast<Constant*>(V1); // X ashr undef --> X |
| case Instruction::Shl: |
| // undef << X -> 0 or X << undef -> 0 |
| return Constant::getNullValue(V1->getType()); |
| } |
| } |
| |
| if (const ConstantExpr *CE1 = dyn_cast<ConstantExpr>(V1)) { |
| if (isa<ConstantExpr>(V2)) { |
| // There are many possible foldings we could do here. We should probably |
| // at least fold add of a pointer with an integer into the appropriate |
| // getelementptr. This will improve alias analysis a bit. |
| } else { |
| // Just implement a couple of simple identities. |
| switch (Opcode) { |
| case Instruction::Add: |
| if (V2->isNullValue()) return const_cast<Constant*>(V1); // X + 0 == X |
| break; |
| case Instruction::Sub: |
| if (V2->isNullValue()) return const_cast<Constant*>(V1); // X - 0 == X |
| break; |
| case Instruction::Mul: |
| if (V2->isNullValue()) return const_cast<Constant*>(V2); // X * 0 == 0 |
| if (const ConstantInt *CI = dyn_cast<ConstantInt>(V2)) |
| if (CI->getZExtValue() == 1) |
| return const_cast<Constant*>(V1); // X * 1 == X |
| break; |
| case Instruction::UDiv: |
| case Instruction::SDiv: |
| if (const ConstantInt *CI = dyn_cast<ConstantInt>(V2)) |
| if (CI->getZExtValue() == 1) |
| return const_cast<Constant*>(V1); // X / 1 == X |
| break; |
| case Instruction::URem: |
| case Instruction::SRem: |
| if (const ConstantInt *CI = dyn_cast<ConstantInt>(V2)) |
| if (CI->getZExtValue() == 1) |
| return Constant::getNullValue(CI->getType()); // X % 1 == 0 |
| break; |
| case Instruction::And: |
| if (cast<ConstantIntegral>(V2)->isAllOnesValue()) |
| return const_cast<Constant*>(V1); // X & -1 == X |
| if (V2->isNullValue()) return const_cast<Constant*>(V2); // X & 0 == 0 |
| if (CE1->isCast() && isa<GlobalValue>(CE1->getOperand(0))) { |
| GlobalValue *CPR = cast<GlobalValue>(CE1->getOperand(0)); |
| |
| // Functions are at least 4-byte aligned. If and'ing the address of a |
| // function with a constant < 4, fold it to zero. |
| if (const ConstantInt *CI = dyn_cast<ConstantInt>(V2)) |
| if (CI->getZExtValue() < 4 && isa<Function>(CPR)) |
| return Constant::getNullValue(CI->getType()); |
| } |
| break; |
| case Instruction::Or: |
| if (V2->isNullValue()) return const_cast<Constant*>(V1); // X | 0 == X |
| if (cast<ConstantIntegral>(V2)->isAllOnesValue()) |
| return const_cast<Constant*>(V2); // X | -1 == -1 |
| break; |
| case Instruction::Xor: |
| if (V2->isNullValue()) return const_cast<Constant*>(V1); // X ^ 0 == X |
| break; |
| } |
| } |
| |
| } else if (isa<ConstantExpr>(V2)) { |
| // If V2 is a constant expr and V1 isn't, flop them around and fold the |
| // other way if possible. |
| switch (Opcode) { |
| case Instruction::Add: |
| case Instruction::Mul: |
| case Instruction::And: |
| case Instruction::Or: |
| case Instruction::Xor: |
| case Instruction::SetEQ: |
| case Instruction::SetNE: |
| // No change of opcode required. |
| return ConstantFoldBinaryInstruction(Opcode, V2, V1); |
| |
| case Instruction::SetLT: |
| case Instruction::SetGT: |
| case Instruction::SetLE: |
| case Instruction::SetGE: |
| // Change the opcode as necessary to swap the operands. |
| Opcode = SetCondInst::getSwappedCondition((Instruction::BinaryOps)Opcode); |
| return ConstantFoldBinaryInstruction(Opcode, V2, V1); |
| |
| case Instruction::Shl: |
| case Instruction::LShr: |
| case Instruction::AShr: |
| case Instruction::Sub: |
| case Instruction::SDiv: |
| case Instruction::UDiv: |
| case Instruction::FDiv: |
| case Instruction::URem: |
| case Instruction::SRem: |
| case Instruction::FRem: |
| default: // These instructions cannot be flopped around. |
| break; |
| } |
| } |
| return 0; |
| } |
| |
| Constant *llvm::ConstantFoldGetElementPtr(const Constant *C, |
| const std::vector<Value*> &IdxList) { |
| if (IdxList.size() == 0 || |
| (IdxList.size() == 1 && cast<Constant>(IdxList[0])->isNullValue())) |
| return const_cast<Constant*>(C); |
| |
| if (isa<UndefValue>(C)) { |
| const Type *Ty = GetElementPtrInst::getIndexedType(C->getType(), IdxList, |
| true); |
| assert(Ty != 0 && "Invalid indices for GEP!"); |
| return UndefValue::get(PointerType::get(Ty)); |
| } |
| |
| Constant *Idx0 = cast<Constant>(IdxList[0]); |
| if (C->isNullValue()) { |
| bool isNull = true; |
| for (unsigned i = 0, e = IdxList.size(); i != e; ++i) |
| if (!cast<Constant>(IdxList[i])->isNullValue()) { |
| isNull = false; |
| break; |
| } |
| if (isNull) { |
| const Type *Ty = GetElementPtrInst::getIndexedType(C->getType(), IdxList, |
| true); |
| assert(Ty != 0 && "Invalid indices for GEP!"); |
| return ConstantPointerNull::get(PointerType::get(Ty)); |
| } |
| |
| if (IdxList.size() == 1) { |
| const Type *ElTy = cast<PointerType>(C->getType())->getElementType(); |
| if (uint32_t ElSize = ElTy->getPrimitiveSize()) { |
| // gep null, C is equal to C*sizeof(nullty). If nullty is a known llvm |
| // type, we can statically fold this. |
| Constant *R = ConstantInt::get(Type::UIntTy, ElSize); |
| R = ConstantExpr::getCast(R, Idx0->getType()); |
| R = ConstantExpr::getMul(R, Idx0); |
| return ConstantExpr::getCast(R, C->getType()); |
| } |
| } |
| } |
| |
| if (ConstantExpr *CE = dyn_cast<ConstantExpr>(const_cast<Constant*>(C))) { |
| // Combine Indices - If the source pointer to this getelementptr instruction |
| // is a getelementptr instruction, combine the indices of the two |
| // getelementptr instructions into a single instruction. |
| // |
| if (CE->getOpcode() == Instruction::GetElementPtr) { |
| const Type *LastTy = 0; |
| for (gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE); |
| I != E; ++I) |
| LastTy = *I; |
| |
| if ((LastTy && isa<ArrayType>(LastTy)) || Idx0->isNullValue()) { |
| std::vector<Value*> NewIndices; |
| NewIndices.reserve(IdxList.size() + CE->getNumOperands()); |
| for (unsigned i = 1, e = CE->getNumOperands()-1; i != e; ++i) |
| NewIndices.push_back(CE->getOperand(i)); |
| |
| // Add the last index of the source with the first index of the new GEP. |
| // Make sure to handle the case when they are actually different types. |
| Constant *Combined = CE->getOperand(CE->getNumOperands()-1); |
| // Otherwise it must be an array. |
| if (!Idx0->isNullValue()) { |
| const Type *IdxTy = Combined->getType(); |
| if (IdxTy != Idx0->getType()) IdxTy = Type::LongTy; |
| Combined = |
| ConstantExpr::get(Instruction::Add, |
| ConstantExpr::getCast(Idx0, IdxTy), |
| ConstantExpr::getCast(Combined, IdxTy)); |
| } |
| |
| NewIndices.push_back(Combined); |
| NewIndices.insert(NewIndices.end(), IdxList.begin()+1, IdxList.end()); |
| return ConstantExpr::getGetElementPtr(CE->getOperand(0), NewIndices); |
| } |
| } |
| |
| // Implement folding of: |
| // int* getelementptr ([2 x int]* cast ([3 x int]* %X to [2 x int]*), |
| // long 0, long 0) |
| // To: int* getelementptr ([3 x int]* %X, long 0, long 0) |
| // |
| if (CE->isCast() && IdxList.size() > 1 && Idx0->isNullValue()) |
| if (const PointerType *SPT = |
| dyn_cast<PointerType>(CE->getOperand(0)->getType())) |
| if (const ArrayType *SAT = dyn_cast<ArrayType>(SPT->getElementType())) |
| if (const ArrayType *CAT = |
| dyn_cast<ArrayType>(cast<PointerType>(C->getType())->getElementType())) |
| if (CAT->getElementType() == SAT->getElementType()) |
| return ConstantExpr::getGetElementPtr( |
| (Constant*)CE->getOperand(0), IdxList); |
| } |
| return 0; |
| } |
| |