X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FVMCore%2FConstantFold.cpp;h=ad9a33f845eda22fbfa5f2bcc7c878a13c19be69;hb=b83eb6447ba155342598f0fabe1f08f5baa9164a;hp=078dffdf83b03567f724840110d4e4188bdc5853;hpb=5fa829c54a38f017fc1077c57716269275524e59;p=oota-llvm.git diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp index 078dffdf83b..ad9a33f845e 100644 --- a/lib/VMCore/ConstantFold.cpp +++ b/lib/VMCore/ConstantFold.cpp @@ -1,115 +1,78 @@ -//===- ConstantHandling.cpp - Implement ConstantHandling.h ----------------===// +//===- ConstantFolding.cpp - LLVM constant folder -------------------------===// // -// This file implements the various intrinsic operations, on constant values. +// 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. // //===----------------------------------------------------------------------===// - -#include "llvm/ConstantHandling.h" -#include "llvm/iPHINode.h" -#include - -AnnotationID ConstRules::AID(AnnotationManager::getID("opt::ConstRules", - &ConstRules::find)); - -// ConstantFoldInstruction - Attempt to constant fold the specified instruction. -// If successful, the constant result is returned, if not, null is returned. // -Constant *ConstantFoldInstruction(Instruction *I) { - if (PHINode *PN = dyn_cast(I)) { - if (PN->getNumIncomingValues() == 0) - return Constant::getNullValue(PN->getType()); - - Constant *Result = dyn_cast(PN->getIncomingValue(0)); - if (Result == 0) return 0; - - // Handle PHI nodes specially here... - for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i) - if (PN->getIncomingValue(i) != Result) - return 0; // Not all the same incoming constants... - - // If we reach here, all incoming values are the same constant. - return Result; - } - - Constant *Op0 = 0; - Constant *Op1 = 0; - - if (I->getNumOperands() != 0) { // Get first operand if it's a constant... - Op0 = dyn_cast(I->getOperand(0)); - if (Op0 == 0) return 0; // Not a constant?, can't fold - - if (I->getNumOperands() != 1) { // Get second operand if it's a constant... - Op1 = dyn_cast(I->getOperand(1)); - if (Op1 == 0) return 0; // Not a constant?, can't fold - } - } +// 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. +// +//===----------------------------------------------------------------------===// - switch (I->getOpcode()) { - case Instruction::Cast: - return ConstRules::get(*Op0)->castTo(Op0, I->getType()); - case Instruction::Not: return ~*Op0; - case Instruction::Add: return *Op0 + *Op1; - case Instruction::Sub: return *Op0 - *Op1; - case Instruction::Mul: return *Op0 * *Op1; - case Instruction::Div: return *Op0 / *Op1; - case Instruction::Rem: return *Op0 % *Op1; - case Instruction::And: return *Op0 & *Op1; - case Instruction::Or: return *Op0 | *Op1; - case Instruction::Xor: return *Op0 ^ *Op1; - - case Instruction::SetEQ: return *Op0 == *Op1; - case Instruction::SetNE: return *Op0 != *Op1; - case Instruction::SetLE: return *Op0 <= *Op1; - case Instruction::SetGE: return *Op0 >= *Op1; - case Instruction::SetLT: return *Op0 < *Op1; - case Instruction::SetGT: return *Op0 > *Op1; - case Instruction::Shl: return *Op0 << *Op1; - case Instruction::Shr: return *Op0 >> *Op1; - default: - return 0; - } -} +#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 +#include +using namespace llvm; -Constant *ConstantFoldCastInstruction(const Constant *V, const Type *DestTy) { - return ConstRules::get(*V)->castTo(V, DestTy); -} +namespace { + struct VISIBILITY_HIDDEN ConstRules { + ConstRules() {} + virtual ~ConstRules() {} -Constant *ConstantFoldUnaryInstruction(unsigned Opcode, const Constant *V) { - switch (Opcode) { - case Instruction::Not: return ~*V; - } - return 0; -} + // 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 *div(const Constant *V1, const Constant *V2) const = 0; + virtual Constant *rem(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 *shr(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; -Constant *ConstantFoldBinaryInstruction(unsigned Opcode, const Constant *V1, - const Constant *V2) { - switch (Opcode) { - case Instruction::Add: return *V1 + *V2; - case Instruction::Sub: return *V1 - *V2; - case Instruction::Mul: return *V1 * *V2; - case Instruction::Div: return *V1 / *V2; - case Instruction::Rem: return *V1 % *V2; - case Instruction::And: return *V1 & *V2; - case Instruction::Or: return *V1 | *V2; - case Instruction::Xor: return *V1 ^ *V2; - - case Instruction::SetEQ: return *V1 == *V2; - case Instruction::SetNE: return *V1 != *V2; - case Instruction::SetLE: return *V1 <= *V2; - case Instruction::SetGE: return *V1 >= *V2; - case Instruction::SetLT: return *V1 < *V2; - case Instruction::SetGT: return *V1 > *V2; - } - return 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; -Constant *ConstantFoldShiftInstruction(unsigned Opcode, const Constant *V1, - const Constant *V2) { - switch (Opcode) { - case Instruction::Shl: return *V1 << *V2; - case Instruction::Shr: return *V1 >> *V2; - default: return 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 + }; } @@ -117,97 +80,97 @@ Constant *ConstantFoldShiftInstruction(unsigned Opcode, const Constant *V1, // 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 +// 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 TemplateRules : public ConstRules { +class VISIBILITY_HIDDEN TemplateRules : public ConstRules { + //===--------------------------------------------------------------------===// // Redirecting functions that cast to the appropriate types //===--------------------------------------------------------------------===// - virtual Constant *op_not(const Constant *V) const { - return SubClassName::Not((const ArgType *)V); - } - - virtual Constant *add(const Constant *V1, const Constant *V2) const { - return SubClassName::Add((const ArgType *)V1, (const ArgType *)V2); + 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 *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 *mul(const Constant *V1, const Constant *V2) const { + return SubClassName::Mul((const ArgType *)V1, (const ArgType *)V2); } - virtual Constant *div(const Constant *V1, const Constant *V2) const { - return SubClassName::Div((const ArgType *)V1, (const ArgType *)V2); + virtual Constant *div(const Constant *V1, const Constant *V2) const { + return SubClassName::Div((const ArgType *)V1, (const ArgType *)V2); } - virtual Constant *rem(const Constant *V1, const Constant *V2) const { - return SubClassName::Rem((const ArgType *)V1, (const ArgType *)V2); + virtual Constant *rem(const Constant *V1, const Constant *V2) const { + return SubClassName::Rem((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_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_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 *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 *shl(const Constant *V1, const Constant *V2) const { + return SubClassName::Shl((const ArgType *)V1, (const ArgType *)V2); } - virtual Constant *shr(const Constant *V1, const Constant *V2) const { - return SubClassName::Shr((const ArgType *)V1, (const ArgType *)V2); + virtual Constant *shr(const Constant *V1, const Constant *V2) const { + return SubClassName::Shr((const ArgType *)V1, (const ArgType *)V2); } - virtual ConstantBool *lessthan(const Constant *V1, - const Constant *V2) const { + 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 ConstantBool *castToBool(const Constant *V) const { + virtual Constant *castToBool(const Constant *V) const { return SubClassName::CastToBool((const ArgType*)V); } - virtual ConstantSInt *castToSByte(const Constant *V) const { + virtual Constant *castToSByte(const Constant *V) const { return SubClassName::CastToSByte((const ArgType*)V); } - virtual ConstantUInt *castToUByte(const Constant *V) const { + virtual Constant *castToUByte(const Constant *V) const { return SubClassName::CastToUByte((const ArgType*)V); } - virtual ConstantSInt *castToShort(const Constant *V) const { + virtual Constant *castToShort(const Constant *V) const { return SubClassName::CastToShort((const ArgType*)V); } - virtual ConstantUInt *castToUShort(const Constant *V) const { + virtual Constant *castToUShort(const Constant *V) const { return SubClassName::CastToUShort((const ArgType*)V); } - virtual ConstantSInt *castToInt(const Constant *V) const { + virtual Constant *castToInt(const Constant *V) const { return SubClassName::CastToInt((const ArgType*)V); } - virtual ConstantUInt *castToUInt(const Constant *V) const { + virtual Constant *castToUInt(const Constant *V) const { return SubClassName::CastToUInt((const ArgType*)V); } - virtual ConstantSInt *castToLong(const Constant *V) const { + virtual Constant *castToLong(const Constant *V) const { return SubClassName::CastToLong((const ArgType*)V); } - virtual ConstantUInt *castToULong(const Constant *V) const { + virtual Constant *castToULong(const Constant *V) const { return SubClassName::CastToULong((const ArgType*)V); } - virtual ConstantFP *castToFloat(const Constant *V) const { + virtual Constant *castToFloat(const Constant *V) const { return SubClassName::CastToFloat((const ArgType*)V); } - virtual ConstantFP *castToDouble(const Constant *V) const { + virtual Constant *castToDouble(const Constant *V) const { return SubClassName::CastToDouble((const ArgType*)V); } - virtual ConstantPointer *castToPointer(const Constant *V, - const PointerType *Ty) const { + virtual Constant *castToPointer(const Constant *V, + const PointerType *Ty) const { return SubClassName::CastToPointer((const ArgType*)V, Ty); } @@ -215,8 +178,6 @@ class TemplateRules : public ConstRules { // Default "noop" implementations //===--------------------------------------------------------------------===// - static Constant *Not(const ArgType *V) { return 0; } - 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; } @@ -227,26 +188,32 @@ class TemplateRules : public ConstRules { static Constant *Xor(const ArgType *V1, const ArgType *V2) { return 0; } static Constant *Shl(const ArgType *V1, const ArgType *V2) { return 0; } static Constant *Shr(const ArgType *V1, const ArgType *V2) { return 0; } - static ConstantBool *LessThan(const ArgType *V1, const ArgType *V2) { + 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 ConstantBool *CastToBool (const Constant *V) { return 0; } - static ConstantSInt *CastToSByte (const Constant *V) { return 0; } - static ConstantUInt *CastToUByte (const Constant *V) { return 0; } - static ConstantSInt *CastToShort (const Constant *V) { return 0; } - static ConstantUInt *CastToUShort(const Constant *V) { return 0; } - static ConstantSInt *CastToInt (const Constant *V) { return 0; } - static ConstantUInt *CastToUInt (const Constant *V) { return 0; } - static ConstantSInt *CastToLong (const Constant *V) { return 0; } - static ConstantUInt *CastToULong (const Constant *V) { return 0; } - static ConstantFP *CastToFloat (const Constant *V) { return 0; } - static ConstantFP *CastToDouble(const Constant *V) { return 0; } - static ConstantPointer *CastToPointer(const Constant *, - const PointerType *) {return 0;} -}; + 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 //===----------------------------------------------------------------------===// @@ -255,8 +222,15 @@ class TemplateRules : public ConstRules { // // EmptyRules provides a concrete base class of ConstRules that does nothing // -struct EmptyRules : public TemplateRules { +namespace { +struct VISIBILITY_HIDDEN EmptyRules + : public TemplateRules { + static Constant *EqualTo(const Constant *V1, const Constant *V2) { + if (V1 == V2) return ConstantBool::getTrue(); + return 0; + } }; +} // end anonymous namespace @@ -266,10 +240,16 @@ struct EmptyRules : public TemplateRules { // // BoolRules provides a concrete base class of ConstRules for the 'bool' type. // -struct BoolRules : public TemplateRules { +namespace { +struct VISIBILITY_HIDDEN BoolRules + : public TemplateRules { + + static Constant *LessThan(const ConstantBool *V1, const ConstantBool *V2) { + return ConstantBool::get(V1->getValue() < V2->getValue()); + } - static Constant *Not(const ConstantBool *V) { - return ConstantBool::get(!V->getValue()); + static Constant *EqualTo(const Constant *V1, const Constant *V2) { + return ConstantBool::get(V1 == V2); } static Constant *And(const ConstantBool *V1, const ConstantBool *V2) { @@ -283,111 +263,212 @@ struct BoolRules : public TemplateRules { 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 //===----------------------------------------------------------------------===// -// PointerRules Class +// NullPointerRules Class //===----------------------------------------------------------------------===// // -// PointerRules provides a concrete base class of ConstRules for pointer types +// NullPointerRules provides a concrete base class of ConstRules for null +// pointers. // -struct PointerRules : public TemplateRules { - static ConstantBool *CastToBool (const Constant *V) { - if (V->isNullValue()) return ConstantBool::False; - return 0; // Can't const prop other types of pointers +namespace { +struct VISIBILITY_HIDDEN NullPointerRules + : public TemplateRules { + static Constant *EqualTo(const Constant *V1, const Constant *V2) { + return ConstantBool::getTrue(); // Null pointers are always equal } - static ConstantSInt *CastToSByte (const Constant *V) { - if (V->isNullValue()) return ConstantSInt::get(Type::SByteTy, 0); - return 0; // Can't const prop other types of pointers + static Constant *CastToBool(const Constant *V) { + return ConstantBool::getFalse(); } - static ConstantUInt *CastToUByte (const Constant *V) { - if (V->isNullValue()) return ConstantUInt::get(Type::UByteTy, 0); - return 0; // Can't const prop other types of pointers + static Constant *CastToSByte (const Constant *V) { + return ConstantInt::get(Type::SByteTy, 0); } - static ConstantSInt *CastToShort (const Constant *V) { - if (V->isNullValue()) return ConstantSInt::get(Type::ShortTy, 0); - return 0; // Can't const prop other types of pointers + static Constant *CastToUByte (const Constant *V) { + return ConstantInt::get(Type::UByteTy, 0); } - static ConstantUInt *CastToUShort(const Constant *V) { - if (V->isNullValue()) return ConstantUInt::get(Type::UShortTy, 0); - return 0; // Can't const prop other types of pointers + static Constant *CastToShort (const Constant *V) { + return ConstantInt::get(Type::ShortTy, 0); } - static ConstantSInt *CastToInt (const Constant *V) { - if (V->isNullValue()) return ConstantSInt::get(Type::IntTy, 0); - return 0; // Can't const prop other types of pointers + static Constant *CastToUShort(const Constant *V) { + return ConstantInt::get(Type::UShortTy, 0); } - static ConstantUInt *CastToUInt (const Constant *V) { - if (V->isNullValue()) return ConstantUInt::get(Type::UIntTy, 0); - return 0; // Can't const prop other types of pointers + static Constant *CastToInt (const Constant *V) { + return ConstantInt::get(Type::IntTy, 0); } - static ConstantSInt *CastToLong (const Constant *V) { - if (V->isNullValue()) return ConstantSInt::get(Type::LongTy, 0); - return 0; // Can't const prop other types of pointers + static Constant *CastToUInt (const Constant *V) { + return ConstantInt::get(Type::UIntTy, 0); } - static ConstantUInt *CastToULong (const Constant *V) { - if (V->isNullValue()) return ConstantUInt::get(Type::ULongTy, 0); - return 0; // Can't const prop other types of pointers + static Constant *CastToLong (const Constant *V) { + return ConstantInt::get(Type::LongTy, 0); } - static ConstantFP *CastToFloat (const Constant *V) { - if (V->isNullValue()) return ConstantFP::get(Type::FloatTy, 0); - return 0; // Can't const prop other types of pointers + static Constant *CastToULong (const Constant *V) { + return ConstantInt::get(Type::ULongTy, 0); } - static ConstantFP *CastToDouble(const Constant *V) { - if (V->isNullValue()) return ConstantFP::get(Type::DoubleTy, 0); - return 0; // Can't const prop other types of pointers + 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 ConstantPointer *CastToPointer(const ConstantPointer *V, - const PointerType *PTy) { - if (V->getType() == PTy) - return const_cast(V); // Allow cast %PTy %ptr to %PTy - if (V->isNullValue()) - return ConstantPointerNull::get(PTy); - return 0; // Can't const prop other types of pointers + 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 Res; + for (unsigned i = 0, e = V1->getNumOperands(); i != e; ++i) + Res.push_back(FP(const_cast(V1->getOperand(i)), + const_cast(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 { + + 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 *Div(const ConstantPacked *V1, const ConstantPacked *V2) { + return EvalVectorOp(V1, V2, ConstantExpr::getDiv); + } + static Constant *Rem(const ConstantPacked *V1, const ConstantPacked *V2) { + return EvalVectorOp(V1, V2, ConstantExpr::getRem); + } + 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 *Shl(const ConstantPacked *V1, const ConstantPacked *V2) { + return EvalVectorOp(V1, V2, ConstantExpr::getShl); + } + static Constant *Shr(const ConstantPacked *V1, const ConstantPacked *V2) { + return EvalVectorOp(V1, V2, ConstantExpr::getShr); + } + 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(V1->getOperand(i)), + const_cast(V2->getOperand(i))); + if (ConstantBool *CB = dyn_cast(C)) + return CB; + } + // Otherwise, could not decide from any element pairs. + return 0; + } +}; +} // end anonymous namespace //===----------------------------------------------------------------------===// -// DirectRules Class +// 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 { +}; +} // end anonymous namespace + + +//===----------------------------------------------------------------------===// +// DirectIntRules Class //===----------------------------------------------------------------------===// // -// DirectRules provides a concrete base classes of ConstRules for a variety of -// different types. This allows the C++ compiler to automatically generate our -// constant handling operations in a typesafe and accurate manner. +// DirectIntRules provides implementations of functions that are valid on +// integer types, but not all types in general. // -template -struct DirectRules : public TemplateRules { - static Constant *Add(const ConstantClass *V1, const ConstantClass *V2) { - BuiltinType R = (BuiltinType)V1->getValue() + (BuiltinType)V2->getValue(); - return ConstantClass::get(*Ty, R); +namespace { +template +struct VISIBILITY_HIDDEN DirectIntRules + : public TemplateRules > { + + 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 ConstantClass *V1, const ConstantClass *V2) { - BuiltinType R = (BuiltinType)V1->getValue() - (BuiltinType)V2->getValue(); - return ConstantClass::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 ConstantClass *V1, const ConstantClass *V2) { - BuiltinType R = (BuiltinType)V1->getValue() * (BuiltinType)V2->getValue(); - return ConstantClass::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 *Div(const ConstantClass *V1, const ConstantClass *V2) { - if (V2->isNullValue()) return 0; - BuiltinType R = (BuiltinType)V1->getValue() / (BuiltinType)V2->getValue(); - return ConstantClass::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 ConstantBool *LessThan(const ConstantClass *V1, - const ConstantClass *V2) { - bool R = (BuiltinType)V1->getValue() < (BuiltinType)V2->getValue(); + static Constant *EqualTo(const ConstantInt *V1, const ConstantInt *V2) { + bool R = (BuiltinType)V1->getZExtValue() == (BuiltinType)V2->getZExtValue(); return ConstantBool::get(R); - } + } - static ConstantPointer *CastToPointer(const ConstantClass *V, - const PointerType *PTy) { + 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 @@ -395,132 +476,1051 @@ struct DirectRules : public TemplateRules { // Casting operators. ick #define DEF_CAST(TYPE, CLASS, CTYPE) \ - static CLASS *CastTo##TYPE (const ConstantClass *V) { \ - return CLASS::get(Type::TYPE##Ty, (CTYPE)(BuiltinType)V->getValue()); \ + 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 , ConstantSInt, signed char) - DEF_CAST(UByte , ConstantUInt, unsigned char) - DEF_CAST(Short , ConstantSInt, signed short) - DEF_CAST(UShort, ConstantUInt, unsigned short) - DEF_CAST(Int , ConstantSInt, signed int) - DEF_CAST(UInt , ConstantUInt, unsigned int) - DEF_CAST(Long , ConstantSInt, int64_t) - DEF_CAST(ULong , ConstantUInt, uint64_t) - DEF_CAST(Float , ConstantFP , float) - DEF_CAST(Double, ConstantFP , double) + 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 -}; - -//===----------------------------------------------------------------------===// -// DirectIntRules Class -//===----------------------------------------------------------------------===// -// -// DirectIntRules provides implementations of functions that are valid on -// integer types, but not all types in general. -// -template -struct DirectIntRules - : public DirectRules > { - static Constant *Not(const ConstantClass *V) { - return ConstantClass::get(*Ty, ~(BuiltinType)V->getValue());; + static Constant *Div(const ConstantInt *V1, const ConstantInt *V2) { + if (V2->isNullValue()) return 0; + if (V2->isAllOnesValue() && // MIN_INT / -1 + (BuiltinType)V1->getZExtValue() == -(BuiltinType)V1->getZExtValue()) + return 0; + BuiltinType R = + (BuiltinType)V1->getZExtValue() / (BuiltinType)V2->getZExtValue(); + return ConstantInt::get(*Ty, R); } - static Constant *Rem(const ConstantClass *V1, - const ConstantClass *V2) { - if (V2->isNullValue()) return 0; - BuiltinType R = (BuiltinType)V1->getValue() % (BuiltinType)V2->getValue(); - return ConstantClass::get(*Ty, R); + static Constant *Rem(const ConstantInt *V1, + const ConstantInt *V2) { + if (V2->isNullValue()) return 0; // X / 0 + if (V2->isAllOnesValue() && // MIN_INT / -1 + (BuiltinType)V1->getZExtValue() == -(BuiltinType)V1->getZExtValue()) + return 0; + BuiltinType R = + (BuiltinType)V1->getZExtValue() % (BuiltinType)V2->getZExtValue(); + return ConstantInt::get(*Ty, R); } - static Constant *And(const ConstantClass *V1, const ConstantClass *V2) { - BuiltinType R = (BuiltinType)V1->getValue() & (BuiltinType)V2->getValue(); - return ConstantClass::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 ConstantClass *V1, const ConstantClass *V2) { - BuiltinType R = (BuiltinType)V1->getValue() | (BuiltinType)V2->getValue(); - return ConstantClass::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 ConstantClass *V1, const ConstantClass *V2) { - BuiltinType R = (BuiltinType)V1->getValue() ^ (BuiltinType)V2->getValue(); - return ConstantClass::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 ConstantClass *V1, const ConstantClass *V2) { - BuiltinType R = (BuiltinType)V1->getValue() << (BuiltinType)V2->getValue(); - return ConstantClass::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 *Shr(const ConstantClass *V1, const ConstantClass *V2) { - BuiltinType R = (BuiltinType)V1->getValue() >> (BuiltinType)V2->getValue(); - return ConstantClass::get(*Ty, R); + static Constant *Shr(const ConstantInt *V1, const ConstantInt *V2) { + BuiltinType R = + (BuiltinType)V1->getZExtValue() >> (BuiltinType)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. -// -template -struct DirectFPRules - : public DirectRules > { - static Constant *Rem(const ConstantClass *V1, const ConstantClass *V2) { +/// DirectFPRules provides implementations of functions that are valid on +/// floating point types, but not all types in general. +/// +namespace { +template +struct VISIBILITY_HIDDEN DirectFPRules + : public TemplateRules > { + + 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 *Rem(const ConstantFP *V1, const ConstantFP *V2) { if (V2->isNullValue()) return 0; BuiltinType Result = std::fmod((BuiltinType)V1->getValue(), (BuiltinType)V2->getValue()); - return ConstantClass::get(*Ty, Result); + return ConstantFP::get(*Ty, Result); + } + static Constant *Div(const ConstantFP *V1, const ConstantFP *V2) { + BuiltinType inf = std::numeric_limits::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 EmptyR; +static ManagedStatic BoolR; +static ManagedStatic NullPointerR; +static ManagedStatic ConstantPackedR; +static ManagedStatic GeneralPackedR; +static ManagedStatic > SByteR; +static ManagedStatic > UByteR; +static ManagedStatic > ShortR; +static ManagedStatic > UShortR; +static ManagedStatic > IntR; +static ManagedStatic > UIntR; +static ManagedStatic > LongR; +static ManagedStatic > ULongR; +static ManagedStatic > FloatR; +static ManagedStatic > 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(V1) || isa(V2) || + isa(V1) || isa(V2) || + isa(V1) || isa(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(V1) && isa(V2)) + return *ConstantPackedR; + return *GeneralPackedR; // Constant folding rules for ConstantAggregateZero. + } +} //===----------------------------------------------------------------------===// -// DirectRules Subclasses +// ConstantFold*Instruction Implementations //===----------------------------------------------------------------------===// // -// Given the DirectRules class we can now implement lots of types with little -// code. Thank goodness C++ compilers are great at stomping out layers of -// templates... can you imagine having to do this all by hand? (/me is lazy :) +// These methods contain the special case hackery required to symbolically +// evaluate some constant expression cases, and use the ConstantRules class to +// evaluate normal constants. // +static unsigned getSize(const Type *Ty) { + unsigned S = Ty->getPrimitiveSize(); + return S ? S : 8; // Treat pointers at 8 bytes +} -// ConstRules::find - Return the constant rules that take care of the specified -// type. -// -Annotation *ConstRules::find(AnnotationID AID, const Annotable *TyA, void *) { - assert(AID == ConstRules::AID && "Bad annotation for factory!"); - const Type *Ty = cast((const Value*)TyA); +/// 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(); - switch (Ty->getPrimitiveID()) { - case Type::BoolTyID: return new BoolRules(); - case Type::PointerTyID: return new PointerRules(); - case Type::SByteTyID: - return new DirectIntRules(); - case Type::UByteTyID: - return new DirectIntRules(); - case Type::ShortTyID: - return new DirectIntRules(); - case Type::UShortTyID: - return new DirectIntRules(); - case Type::IntTyID: - return new DirectIntRules(); - case Type::UIntTyID: - return new DirectIntRules(); - case Type::LongTyID: - return new DirectIntRules(); - case Type::ULongTyID: - return new DirectIntRules(); - case Type::FloatTyID: - return new DirectFPRules(); - case Type::DoubleTyID: - return new DirectFPRules(); - default: - return new EmptyRules(); + // 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 Result; + + // If the src and dest elements are both integers, just cast each one + // which will do the appropriate bit-convert. + if (SrcEltTy->isIntegral() && DstEltTy->isIntegral()) { + for (unsigned i = 0; i != SrcNumElts; ++i) + Result.push_back(ConstantExpr::getCast(CP->getOperand(i), + DstEltTy)); + return ConstantPacked::get(Result); + } + + if (SrcEltTy->isIntegral()) { + // Otherwise, this is an int-to-fp cast. + assert(DstEltTy->isFloatingPoint()); + if (DstEltTy->getTypeID() == Type::DoubleTyID) { + for (unsigned i = 0; i != SrcNumElts; ++i) { + double V = + BitsToDouble(cast(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(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(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(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; } + + +Constant *llvm::ConstantFoldCastInstruction(const Constant *V, + const Type *DestTy) { + if (V->getType() == DestTy) return (Constant*)V; + + // Cast of a global address to boolean is always true. + if (const GlobalValue *GV = dyn_cast(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(); + } else if (const ConstantExpr *CE = dyn_cast(V)) { + if (CE->getOpcode() == Instruction::Cast) { + Constant *Op = const_cast(CE->getOperand(0)); + // Try to not produce a cast of a cast, which is almost always redundant. + if (!Op->getType()->isFloatingPoint() && + !CE->getType()->isFloatingPoint() && + !DestTy->isFloatingPoint()) { + unsigned S1 = getSize(Op->getType()), S2 = getSize(CE->getType()); + unsigned S3 = getSize(DestTy); + if (Op->getType() == DestTy && S3 >= S2) + return Op; + if (S1 >= S2 && S2 >= S3) + return ConstantExpr::getCast(Op, DestTy); + if (S1 <= S2 && S2 >= S3 && S1 <= S3) + return ConstantExpr::getCast(Op, 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); + } + } else if (isa(V)) { + return UndefValue::get(DestTy); + } + + // Check to see if we are casting an pointer to an aggregate to a pointer to + // the first element. If so, return the appropriate GEP instruction. + if (const PointerType *PTy = dyn_cast(V->getType())) + if (const PointerType *DPTy = dyn_cast(DestTy)) { + std::vector IdxList; + IdxList.push_back(Constant::getNullValue(Type::IntTy)); + const Type *ElTy = PTy->getElementType(); + while (ElTy != DPTy->getElementType()) { + if (const StructType *STy = dyn_cast(ElTy)) { + if (STy->getNumElements() == 0) break; + ElTy = STy->getElementType(0); + IdxList.push_back(Constant::getNullValue(Type::UIntTy)); + } else if (const SequentialType *STy = dyn_cast(ElTy)) { + if (isa(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(V),IdxList); + } + + // Handle casts from one packed constant to another. We know that the src and + // dest type have the same size. + if (const PackedType *DestPTy = dyn_cast(DestTy)) { + if (const PackedType *SrcTy = dyn_cast(V->getType())) { + assert(DestPTy->getElementType()->getPrimitiveSizeInBits() * + DestPTy->getNumElements() == + SrcTy->getElementType()->getPrimitiveSizeInBits() * + SrcTy->getNumElements() && "Not cast between same sized vectors!"); + if (isa(V)) + return Constant::getNullValue(DestTy); + if (isa(V)) + return UndefValue::get(DestTy); + if (const ConstantPacked *CP = dyn_cast(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(CP->getOperand(i)) && + !isa(CP->getOperand(i))) { + AllSimpleConstants = false; + break; + } + } + + // If all of the elements are simple constants, we can fold this. + if (AllSimpleConstants) + return CastConstantPacked(const_cast(CP), DestPTy); + } + } + } + + 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(DestTy)); + default: return 0; + } +} + +Constant *llvm::ConstantFoldSelectInstruction(const Constant *Cond, + const Constant *V1, + const Constant *V2) { + if (const ConstantBool *CB = dyn_cast(Cond)) + return const_cast(CB->getValue() ? V1 : V2); + + if (isa(V1)) return const_cast(V2); + if (isa(V2)) return const_cast(V1); + if (isa(Cond)) return const_cast(V1); + if (V1 == V2) return const_cast(V1); + return 0; +} + +Constant *llvm::ConstantFoldExtractElementInstruction(const Constant *Val, + const Constant *Idx) { + if (isa(Val)) // ee(undef, x) -> undef + return UndefValue::get(cast(Val->getType())->getElementType()); + if (Val->isNullValue()) // ee(zero, x) -> zero + return Constant::getNullValue( + cast(Val->getType())->getElementType()); + + if (const ConstantPacked *CVal = dyn_cast(Val)) { + if (const ConstantInt *CIdx = dyn_cast(Idx)) { + return const_cast(CVal->getOperand(CIdx->getZExtValue())); + } else if (isa(Idx)) { + // ee({w,x,y,z}, undef) -> w (an arbitrary value). + return const_cast(CVal->getOperand(0)); + } + } + return 0; +} + +Constant *llvm::ConstantFoldInsertElementInstruction(const Constant *Val, + const Constant *Elt, + const Constant *Idx) { + const ConstantInt *CIdx = dyn_cast(Idx); + if (!CIdx) return 0; + uint64_t idxVal = CIdx->getZExtValue(); + if (const UndefValue *UVal = dyn_cast(Val)) { + // Insertion of scalar constant into packed undef + // Optimize away insertion of undef + if (isa(Elt)) + return const_cast(Val); + // Otherwise break the aggregate undef into multiple undefs and do + // the insertion + unsigned numOps = + cast(Val->getType())->getNumElements(); + std::vector 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(Op)); + } + return ConstantPacked::get(Ops); + } + if (const ConstantAggregateZero *CVal = + dyn_cast(Val)) { + // Insertion of scalar constant into packed aggregate zero + // Optimize away insertion of zero + if (Elt->isNullValue()) + return const_cast(Val); + // Otherwise break the aggregate zero into multiple zeros and do + // the insertion + unsigned numOps = + cast(Val->getType())->getNumElements(); + std::vector 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(Op)); + } + return ConstantPacked::get(Ops); + } + if (const ConstantPacked *CVal = dyn_cast(Val)) { + // Insertion of scalar constant into packed constant + std::vector Ops; + Ops.reserve(CVal->getNumOperands()); + for (unsigned i = 0; i < CVal->getNumOperands(); ++i) { + const Constant *Op = + (i == idxVal) ? Elt : cast(CVal->getOperand(i)); + Ops.push_back(const_cast(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(Ty)) return true; // Can't say. + if (const StructType *STy = dyn_cast(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(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(C1) || !isa(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. + C1 = ConstantExpr::getSignExtend(C1, Type::LongTy); + C2 = ConstantExpr::getSignExtend(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(C1)->getSExtValue() < + cast(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(V1) && !isa(V1)) { + if (!isa(V2) && !isa(V2)) { + // We distilled this down to a simple case, use the standard constant + // folder. + ConstantBool *R = dyn_cast(ConstantExpr::getSetEQ(V1, V2)); + if (R && R->getValue()) return Instruction::SetEQ; + R = dyn_cast(ConstantExpr::getSetLT(V1, V2)); + if (R && R->getValue()) return Instruction::SetLT; + R = dyn_cast(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(V1)) { + if (isa(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(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(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(V1); + Constant *CE1Op0 = CE1->getOperand(0); + + switch (CE1->getOpcode()) { + case Instruction::Cast: + // 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(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(V2)) + if (isa(CE1->getType()) && + CE2->getOpcode() == Instruction::Cast && + 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(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(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(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(V2)) { + if (isa(CE1Op0)) { + // FIXME: This is not true with external weak references. + return Instruction::SetLT; + } else if (const GlobalValue *CPR1 = dyn_cast(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(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(CE1Op0) && isa(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(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(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::Div: C = ConstRules::get(V1, V2).div(V1, V2); break; + case Instruction::Rem: C = ConstRules::get(V1, V2).rem(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::Shr: C = ConstRules::get(V1, V2).shr(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(V1) || isa(V2)) + return UndefValue::get(Type::BoolTy); + switch (evaluateRelation(const_cast(V1), + const_cast(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(V1) || isa(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::Div: + case Instruction::Rem: + if (!isa(V2)) // undef/X -> 0 + return Constant::getNullValue(V1->getType()); + return const_cast(V2); // X/undef -> undef + case Instruction::Or: // X|undef -> -1 + return ConstantInt::getAllOnesValue(V1->getType()); + case Instruction::Shr: + if (!isa(V2)) { + if (V1->getType()->isSigned()) + return const_cast(V1); // undef >>s X -> undef + // undef >>u X -> 0 + } else if (isa(V1)) { + return const_cast(V1); // undef >> undef -> undef + } else { + if (V1->getType()->isSigned()) + return const_cast(V1); // X >>s undef -> X + // X >>u undef -> 0 + } + return Constant::getNullValue(V1->getType()); + + case Instruction::Shl: + // undef << X -> 0 X << undef -> 0 + return Constant::getNullValue(V1->getType()); + } + } + + if (const ConstantExpr *CE1 = dyn_cast(V1)) { + if (const ConstantExpr *CE2 = dyn_cast(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(V1); // X + 0 == X + break; + case Instruction::Sub: + if (V2->isNullValue()) return const_cast(V1); // X - 0 == X + break; + case Instruction::Mul: + if (V2->isNullValue()) return const_cast(V2); // X * 0 == 0 + if (const ConstantInt *CI = dyn_cast(V2)) + if (CI->getZExtValue() == 1) + return const_cast(V1); // X * 1 == X + break; + case Instruction::Div: + if (const ConstantInt *CI = dyn_cast(V2)) + if (CI->getZExtValue() == 1) + return const_cast(V1); // X / 1 == X + break; + case Instruction::Rem: + if (const ConstantInt *CI = dyn_cast(V2)) + if (CI->getZExtValue() == 1) + return Constant::getNullValue(CI->getType()); // X % 1 == 0 + break; + case Instruction::And: + if (cast(V2)->isAllOnesValue()) + return const_cast(V1); // X & -1 == X + if (V2->isNullValue()) return const_cast(V2); // X & 0 == 0 + if (CE1->getOpcode() == Instruction::Cast && + isa(CE1->getOperand(0))) { + GlobalValue *CPR = cast(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(V2)) + if (CI->getZExtValue() < 4 && isa(CPR)) + return Constant::getNullValue(CI->getType()); + } + break; + case Instruction::Or: + if (V2->isNullValue()) return const_cast(V1); // X | 0 == X + if (cast(V2)->isAllOnesValue()) + return const_cast(V2); // X | -1 == -1 + break; + case Instruction::Xor: + if (V2->isNullValue()) return const_cast(V1); // X ^ 0 == X + break; + } + } + + } else if (const ConstantExpr *CE2 = dyn_cast(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::Shr: + case Instruction::Sub: + case Instruction::Div: + case Instruction::Rem: + default: // These instructions cannot be flopped around. + break; + } + } + return 0; +} + +Constant *llvm::ConstantFoldGetElementPtr(const Constant *C, + const std::vector &IdxList) { + if (IdxList.size() == 0 || + (IdxList.size() == 1 && cast(IdxList[0])->isNullValue())) + return const_cast(C); + + if (isa(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(IdxList[0]); + if (C->isNullValue()) { + bool isNull = true; + for (unsigned i = 0, e = IdxList.size(); i != e; ++i) + if (!cast(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(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(const_cast(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(LastTy)) || Idx0->isNullValue()) { + std::vector 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->getOpcode() == Instruction::Cast && IdxList.size() > 1 && + Idx0->isNullValue()) + if (const PointerType *SPT = + dyn_cast(CE->getOperand(0)->getType())) + if (const ArrayType *SAT = dyn_cast(SPT->getElementType())) + if (const ArrayType *CAT = + dyn_cast(cast(C->getType())->getElementType())) + if (CAT->getElementType() == SAT->getElementType()) + return ConstantExpr::getGetElementPtr( + (Constant*)CE->getOperand(0), IdxList); + } + return 0; +} +