X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FLevelRaise.cpp;h=f246116a2ee7822ee0ce363d5f56ecb05d98a88e;hb=c966a2acee176369be2f901e32c346c176b7f772;hp=61610acae9178b58c205befafb410d8d21142d3e;hpb=dedee7bf15cb5dca3bbca20b67ff5b6a47ce4605;p=oota-llvm.git diff --git a/lib/Transforms/LevelRaise.cpp b/lib/Transforms/LevelRaise.cpp index 61610acae91..f246116a2ee 100644 --- a/lib/Transforms/LevelRaise.cpp +++ b/lib/Transforms/LevelRaise.cpp @@ -2,54 +2,55 @@ // // This file implements the 'raising' part of the LevelChange API. This is // useful because, in general, it makes the LLVM code terser and easier to -// analyze. Note that it is good to run DCE after doing this transformation. -// -// Eliminate silly things in the source that do not effect the level, but do -// clean up the code: -// * Casts of casts -// - getelementptr/load & getelementptr/store are folded into a direct -// load or store -// - Convert this code (for both alloca and malloc): -// %reg110 = shl uint %n, ubyte 2 ;; -// %reg108 = alloca ubyte, uint %reg110 ;; -// %cast76 = cast ubyte* %reg108 to uint* ;; -// To: %cast76 = alloca uint, uint %n -// Convert explicit addressing to use getelementptr instruction where possible -// - ... -// -// Convert explicit addressing on pointers to use getelementptr instruction. -// - If a pointer is used by arithmetic operation, insert an array casted -// version into the source program, only for the following pointer types: -// * Method argument pointers -// - Pointers returned by alloca or malloc -// - Pointers returned by function calls -// - If a pointer is indexed with a value scaled by a constant size equal -// to the element size of the array, the expression is replaced with a -// getelementptr instruction. +// analyze. // //===----------------------------------------------------------------------===// -#include "llvm/Transforms/LevelChange.h" -#include "llvm/Method.h" -#include "llvm/Support/STLExtras.h" +#include "llvm/Transforms/RaisePointerReferences.h" +#include "llvm/Transforms/Utils/Local.h" +#include "TransformInternals.h" #include "llvm/iOther.h" #include "llvm/iMemory.h" -#include "llvm/ConstPoolVals.h" -#include "llvm/Target/TargetData.h" -#include "llvm/Optimizations/ConstantHandling.h" -#include +#include "llvm/Pass.h" +#include "llvm/ConstantHandling.h" +#include "llvm/Analysis/Expressions.h" +#include "llvm/Analysis/Verifier.h" +#include "llvm/Transforms/Utils/BasicBlockUtils.h" +#include "Support/STLExtras.h" +#include "Support/Statistic.h" +#include "Support/CommandLine.h" #include +using std::cerr; + +// StartInst - This enables the -raise-start-inst=foo option to cause the level +// raising pass to start at instruction "foo", which is immensely useful for +// debugging! +// +static cl::opt +StartInst("raise-start-inst", cl::Hidden, cl::value_desc("inst name"), + cl::desc("Start raise pass at the instruction with the specified name")); + +static Statistic<> +NumLoadStorePeepholes("raise", "Number of load/store peepholes"); + +static Statistic<> +NumGEPInstFormed("raise", "Number of other getelementptr's formed"); + +static Statistic<> +NumExprTreesConv("raise", "Number of expression trees converted"); -#include "llvm/Assembly/Writer.h" +static Statistic<> +NumCastOfCast("raise", "Number of cast-of-self removed"); + +static Statistic<> +NumDCEorCP("raise", "Number of insts DCEd or constprop'd"); + +static Statistic<> +NumVarargCallChanges("raise", "Number of vararg call peepholes"); -//#define DEBUG_PEEPHOLE_INSTS 1 -#ifdef DEBUG_PEEPHOLE_INSTS #define PRINT_PEEPHOLE(ID, NUM, I) \ - cerr << "Inst P/H " << ID << "[" << NUM << "] " << I; -#else -#define PRINT_PEEPHOLE(ID, NUM, I) -#endif + DEBUG(std::cerr << "Inst P/H " << ID << "[" << NUM << "] " << I) #define PRINT_PEEPHOLE1(ID, I1) do { PRINT_PEEPHOLE(ID, 0, I1); } while (0) #define PRINT_PEEPHOLE2(ID, I1, I2) \ @@ -57,43 +58,9 @@ #define PRINT_PEEPHOLE3(ID, I1, I2, I3) \ do { PRINT_PEEPHOLE(ID, 0, I1); PRINT_PEEPHOLE(ID, 1, I2); \ PRINT_PEEPHOLE(ID, 2, I3); } while (0) - - -// TargetData Hack: Eventually we will have annotations given to us by the -// backend so that we know stuff about type size and alignments. For now -// though, just use this, because it happens to match the model that GCC uses. -// -const TargetData TD("LevelRaise: Should be GCC though!"); - - -// losslessCastableTypes - Return true if the types are bitwise equivalent. -// This predicate returns true if it is possible to cast from one type to -// another without gaining or losing precision, or altering the bits in any way. -// -static bool losslessCastableTypes(const Type *T1, const Type *T2) { - if (!T1->isPrimitiveType() && !isa(T1)) return false; - if (!T2->isPrimitiveType() && !isa(T2)) return false; - - if (T1->getPrimitiveID() == T2->getPrimitiveID()) - return true; // Handles identity cast, and cast of differing pointer types - - // Now we know that they are two differing primitive or pointer types - switch (T1->getPrimitiveID()) { - case Type::UByteTyID: return T2 == Type::SByteTy; - case Type::SByteTyID: return T2 == Type::UByteTy; - case Type::UShortTyID: return T2 == Type::ShortTy; - case Type::ShortTyID: return T2 == Type::UShortTy; - case Type::UIntTyID: return T2 == Type::IntTy; - case Type::IntTyID: return T2 == Type::UIntTy; - case Type::ULongTyID: - case Type::LongTyID: - case Type::PointerTyID: - return T2 == Type::ULongTy || T2 == Type::LongTy || - T2->getPrimitiveID() == Type::PointerTyID; - default: - return false; // Other types have no identity values - } -} +#define PRINT_PEEPHOLE4(ID, I1, I2, I3, I4) \ + do { PRINT_PEEPHOLE(ID, 0, I1); PRINT_PEEPHOLE(ID, 1, I2); \ + PRINT_PEEPHOLE(ID, 2, I3); PRINT_PEEPHOLE(ID, 3, I4); } while (0) // isReinterpretingCast - Return true if the cast instruction specified will @@ -101,431 +68,316 @@ static bool losslessCastableTypes(const Type *T1, const Type *T2) { // cast instruction would cause the underlying bits to change. // static inline bool isReinterpretingCast(const CastInst *CI) { - return !losslessCastableTypes(CI->getOperand(0)->getType(), CI->getType()); -} - - -// getPointedToStruct - If the argument is a pointer type, and the pointed to -// value is a struct type, return the struct type, else return null. -// -static const StructType *getPointedToStruct(const Type *Ty) { - const PointerType *PT = dyn_cast(Ty); - return PT ? dyn_cast(PT->getValueType()) : 0; -} - - -// getStructOffsetType - Return a vector of offsets that are to be used to index -// into the specified struct type to get as close as possible to index as we -// can. Note that it is possible that we cannot get exactly to Offset, in which -// case we update offset to be the offset we actually obtained. The resultant -// leaf type is returned. -// -static const Type *getStructOffsetType(const Type *Ty, unsigned &Offset, - vector &Offsets) { - if (!isa(Ty)) { - Offset = 0; // Return the offset that we were able to acheive - return Ty; // Return the leaf type - } - - assert(Offset < TD.getTypeSize(Ty) && "Offset not in struct!"); - const StructType *STy = cast(Ty); - const StructLayout *SL = TD.getStructLayout(STy); - - // This loop terminates always on a 0 <= i < MemberOffsets.size() - unsigned i; - for (i = 0; i < SL->MemberOffsets.size()-1; ++i) - if (Offset >= SL->MemberOffsets[i] && Offset < SL->MemberOffsets[i+1]) - break; - - assert(Offset >= SL->MemberOffsets[i] && Offset < SL->MemberOffsets[i+1]); - - // Make sure to save the current index... - Offsets.push_back(ConstPoolUInt::get(Type::UByteTy, i)); - - unsigned SubOffs = Offset - SL->MemberOffsets[i]; - const Type *LeafTy = getStructOffsetType(STy->getElementTypes()[i], SubOffs, - Offsets); - Offset = SL->MemberOffsets[i] + SubOffs; - return LeafTy; + return!CI->getOperand(0)->getType()->isLosslesslyConvertableTo(CI->getType()); } - -// ReplaceInstWithValue - Replace all uses of an instruction (specified by BI) -// with a value, then remove and delete the original instruction. +// Peephole optimize the following instructions: +// %t1 = cast ? to x * +// %t2 = add x * %SP, %t1 ;; Constant must be 2nd operand // -static void ReplaceInstWithValue(BasicBlock::InstListType &BIL, - BasicBlock::iterator &BI, Value *V) { - Instruction *I = *BI; - // Replaces all of the uses of the instruction with uses of the value - I->replaceAllUsesWith(V); - - // Remove the unneccesary instruction now... - BIL.remove(BI); - - // Make sure to propogate a name if there is one already... - if (I->hasName() && !V->hasName()) - V->setName(I->getName(), BIL.getParent()->getSymbolTable()); - - // Remove the dead instruction now... - delete I; -} - - -// ReplaceInstWithInst - Replace the instruction specified by BI with the -// instruction specified by I. The original instruction is deleted and BI is -// updated to point to the new instruction. +// Into: %t3 = getelementptr {<...>} * %SP, +// %t2 = cast * %t3 to {<...>}* // -static void ReplaceInstWithInst(BasicBlock::InstListType &BIL, - BasicBlock::iterator &BI, Instruction *I) { - assert(I->getParent() == 0 && - "ReplaceInstWithInst: Instruction already inserted into basic block!"); - - // Insert the new instruction into the basic block... - BI = BIL.insert(BI, I)+1; - - // Replace all uses of the old instruction, and delete it. - ReplaceInstWithValue(BIL, BI, I); - - // Reexamine the instruction just inserted next time around the cleanup pass - // loop. - --BI; -} - - -// ExpressionConvertableToType - Return true if it is possible -static bool ExpressionConvertableToType(Value *V, const Type *Ty) { - Instruction *I = dyn_cast(V); - if (I == 0) { - // It's not an instruction, check to see if it's a constant... all constants - // can be converted to an equivalent value (except pointers, they can't be - // const prop'd in general). - // - if (isa(V) && - !isa(V->getType()) && !isa(Ty)) return true; - - return false; // Otherwise, we can't convert! - } - if (I->getType() == Ty) return false; // Expression already correct type! - - switch (I->getOpcode()) { - case Instruction::Cast: - // We can convert the expr if the cast destination type is losslessly - // convertable to the requested type. - return losslessCastableTypes(Ty, I->getType()); - - case Instruction::Add: - case Instruction::Sub: - return ExpressionConvertableToType(I->getOperand(0), Ty) && - ExpressionConvertableToType(I->getOperand(1), Ty); - case Instruction::Shl: - case Instruction::Shr: - return ExpressionConvertableToType(I->getOperand(0), Ty); - } - return false; -} - - -static Value *ConvertExpressionToType(Value *V, const Type *Ty) { - assert(ExpressionConvertableToType(V, Ty) && "Value is not convertable!"); - Instruction *I = dyn_cast(V); - if (I == 0) - if (ConstPoolVal *CPV = cast(V)) { - // Constants are converted by constant folding the cast that is required. - // We assume here that all casts are implemented for constant prop. - Value *Result = opt::ConstantFoldCastInstruction(CPV, Ty); - if (!Result) cerr << "Couldn't fold " << CPV << " to " << Ty << endl; - assert(Result && "ConstantFoldCastInstruction Failed!!!"); - return Result; - } - - - BasicBlock *BB = I->getParent(); - BasicBlock::InstListType &BIL = BB->getInstList(); - string Name = I->getName(); if (!Name.empty()) I->setName(""); - Instruction *Res; // Result of conversion - - //cerr << endl << endl << "Type:\t" << Ty << "\nInst: " << I << "BB Before: " << BB << endl; +static bool HandleCastToPointer(BasicBlock::iterator BI, + const PointerType *DestPTy) { + CastInst &CI = cast(*BI); + if (CI.use_empty()) return false; - switch (I->getOpcode()) { - case Instruction::Cast: - Res = new CastInst(I->getOperand(0), Ty, Name); - break; - - case Instruction::Add: - case Instruction::Sub: - Res = BinaryOperator::create(cast(I)->getOpcode(), - ConvertExpressionToType(I->getOperand(0), Ty), - ConvertExpressionToType(I->getOperand(1), Ty), - Name); - break; - - case Instruction::Shl: - case Instruction::Shr: - Res = new ShiftInst(cast(I)->getOpcode(), - ConvertExpressionToType(I->getOperand(0), Ty), - I->getOperand(1), Name); - break; - - default: - assert(0 && "Expression convertable, but don't know how to convert?"); - return 0; - } - - BasicBlock::iterator It = find(BIL.begin(), BIL.end(), I); - assert(It != BIL.end() && "Instruction not in own basic block??"); - BIL.insert(It, Res); - - //cerr << "RInst: " << Res << "BB After: " << BB << endl << endl; - - return Res; -} - - - -// DoInsertArrayCast - If the argument value has a pointer type, and if the -// argument value is used as an array, insert a cast before the specified -// basic block iterator that casts the value to an array pointer. Return the -// new cast instruction (in the CastResult var), or null if no cast is inserted. -// -static bool DoInsertArrayCast(Method *CurMeth, Value *V, BasicBlock *BB, - BasicBlock::iterator &InsertBefore, - CastInst *&CastResult) { - const PointerType *ThePtrType = dyn_cast(V->getType()); - if (!ThePtrType) return false; - bool InsertCast = false; - - for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) { - Instruction *Inst = cast(*I); - switch (Inst->getOpcode()) { - default: break; // Not an interesting use... - case Instruction::Add: // It's being used as an array index! - //case Instruction::Sub: - InsertCast = true; - break; - case Instruction::Cast: // There is already a cast instruction! - if (const PointerType *PT = dyn_cast(Inst->getType())) - if (const ArrayType *AT = dyn_cast(PT->getValueType())) - if (AT->getElementType() == ThePtrType->getValueType()) { - // Cast already exists! Return the existing one! - CastResult = cast(Inst); - return false; // No changes made to program though... - } - break; + // Scan all of the uses, looking for any uses that are not add + // instructions. If we have non-adds, do not make this transformation. + // + for (Value::use_iterator I = CI.use_begin(), E = CI.use_end(); + I != E; ++I) { + if (BinaryOperator *BO = dyn_cast(*I)) { + if (BO->getOpcode() != Instruction::Add || + // Avoid add sbyte* %X, %X cases... + BO->getOperand(0) == BO->getOperand(1)) + return false; + } else { + return false; } } - if (!InsertCast) return false; // There is no reason to insert a cast! + std::vector Indices; + Value *Src = CI.getOperand(0); + const Type *Result = ConvertableToGEP(DestPTy, Src, Indices, &BI); + if (Result == 0) return false; // Not convertable... - // Insert a cast! - const Type *ElTy = ThePtrType->getValueType(); - const PointerType *DestTy = PointerType::get(ArrayType::get(ElTy)); + PRINT_PEEPHOLE2("cast-add-to-gep:in", Src, CI); - CastResult = new CastInst(V, DestTy); - BB->getInstList().insert(InsertBefore, CastResult); - //cerr << "Inserted cast: " << CastResult; - return true; // Made a change! -} + // If we have a getelementptr capability... transform all of the + // add instruction uses into getelementptr's. + while (!CI.use_empty()) { + BinaryOperator *I = cast(*CI.use_begin()); + assert(I->getOpcode() == Instruction::Add && I->getNumOperands() == 2 && + "Use is not a valid add instruction!"); + + // Get the value added to the cast result pointer... + Value *OtherPtr = I->getOperand((I->getOperand(0) == &CI) ? 1 : 0); + + Instruction *GEP = new GetElementPtrInst(OtherPtr, Indices, I->getName()); + PRINT_PEEPHOLE1("cast-add-to-gep:i", I); + + if (GEP->getType() == I->getType()) { + // Replace the old add instruction with the shiny new GEP inst + ReplaceInstWithInst(I, GEP); + } else { + // If the type produced by the gep instruction differs from the original + // add instruction type, insert a cast now. + // + // Insert the GEP instruction before the old add instruction... + I->getParent()->getInstList().insert(I, GEP); -// DoInsertArrayCasts - Loop over all "incoming" values in the specified method, -// inserting a cast for pointer values that are used as arrays. For our -// purposes, an incoming value is considered to be either a value that is -// either a method parameter, a value created by alloca or malloc, or a value -// returned from a function call. All casts are kept attached to their original -// values through the PtrCasts map. -// -static bool DoInsertArrayCasts(Method *M, map &PtrCasts) { - assert(!M->isExternal() && "Can't handle external methods!"); + PRINT_PEEPHOLE1("cast-add-to-gep:o", GEP); + GEP = new CastInst(GEP, I->getType()); - // Insert casts for all arguments to the function... - bool Changed = false; - BasicBlock *CurBB = M->front(); - BasicBlock::iterator It = CurBB->begin(); - for (Method::ArgumentListType::iterator AI = M->getArgumentList().begin(), - AE = M->getArgumentList().end(); AI != AE; ++AI) { - CastInst *TheCast = 0; - if (DoInsertArrayCast(M, *AI, CurBB, It, TheCast)) { - It = CurBB->begin(); // We might have just invalidated the iterator! - Changed = true; // Yes we made a change - ++It; // Insert next cast AFTER this one... + // Replace the old add instruction with the shiny new GEP inst + ReplaceInstWithInst(I, GEP); } - if (TheCast) // Is there a cast associated with this value? - PtrCasts[*AI] = TheCast; // Yes, add it to the map... + PRINT_PEEPHOLE1("cast-add-to-gep:o", GEP); } - - // TODO: insert casts for alloca, malloc, and function call results. Also, - // look for pointers that already have casts, to add to the map. - - return Changed; + return true; } - - - -// DoElminatePointerArithmetic - Loop over each incoming pointer variable, -// replacing indexing arithmetic with getelementptr calls. +// Peephole optimize the following instructions: +// %t1 = cast ulong to {<...>} * +// %t2 = add {<...>} * %SP, %t1 ;; Constant must be 2nd operand // -static bool DoEliminatePointerArithmetic(const pair &Val) { - Value *V = Val.first; // The original pointer - CastInst *CV = Val.second; // The array casted version of the pointer... - - for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) { - Instruction *Inst = cast(*I); - if (Inst->getOpcode() != Instruction::Add) - continue; // We only care about add instructions - - BinaryOperator *Add = cast(Inst); - - // Make sure the array is the first operand of the add expression... - if (Add->getOperand(0) != V) - Add->swapOperands(); - - // Get the amount added to the pointer value... - Value *AddAmount = Add->getOperand(1); - - - } - return false; -} - - -// Peephole Malloc instructions: we take a look at the use chain of the -// malloc instruction, and try to find out if the following conditions hold: -// 1. The malloc is of the form: 'malloc [sbyte], uint ' -// 2. The only users of the malloc are cast instructions -// 3. Of the cast instructions, there is only one destination pointer type -// [RTy] where the size of the pointed to object is equal to the number -// of bytes allocated. +// or +// %t1 = cast {<...>}* %SP to int* +// %t5 = cast ulong to int* +// %t2 = add int* %t1, %t5 ;; int is same size as field // -// If these conditions hold, we convert the malloc to allocate an [RTy] -// element. This should be extended in the future to handle arrays. TODO +// Into: %t3 = getelementptr {<...>} * %SP, +// %t2 = cast * %t3 to {<...>}* // -static bool PeepholeMallocInst(BasicBlock *BB, BasicBlock::iterator &BI) { - MallocInst *MI = cast(*BI); - if (!MI->isArrayAllocation()) return false; // No array allocation? +static bool PeepholeOptimizeAddCast(BasicBlock *BB, BasicBlock::iterator &BI, + Value *AddOp1, CastInst *AddOp2) { + const CompositeType *CompTy; + Value *OffsetVal = AddOp2->getOperand(0); + Value *SrcPtr; // Of type pointer to struct... + + if ((CompTy = getPointedToComposite(AddOp1->getType()))) { + SrcPtr = AddOp1; // Handle the first case... + } else if (CastInst *AddOp1c = dyn_cast(AddOp1)) { + SrcPtr = AddOp1c->getOperand(0); // Handle the second case... + CompTy = getPointedToComposite(SrcPtr->getType()); + } - ConstPoolUInt *Amt = dyn_cast(MI->getArraySize()); - if (Amt == 0 || MI->getAllocatedType() != ArrayType::get(Type::SByteTy)) + // Only proceed if we have detected all of our conditions successfully... + if (!CompTy || !SrcPtr || !OffsetVal->getType()->isInteger()) return false; - // Get the number of bytes allocated... - unsigned Size = Amt->getValue(); - const Type *ResultTy = 0; + std::vector Indices; + if (!ConvertableToGEP(SrcPtr->getType(), OffsetVal, Indices, &BI)) + return false; // Not convertable... perhaps next time - // Loop over all of the uses of the malloc instruction, inspecting casts. - for (Value::use_iterator I = MI->use_begin(), E = MI->use_end(); - I != E; ++I) { - if (!isa(*I)) { - //cerr << "\tnon" << *I; - return false; // A non cast user? - } - CastInst *CI = cast(*I); - //cerr << "\t" << CI; - - // We only work on casts to pointer types for sure, be conservative - if (!isa(CI->getType())) { - cerr << "Found cast of malloc value to non pointer type:\n" << CI; - return false; - } - - const Type *DestTy = cast(CI->getType())->getValueType(); - if (TD.getTypeSize(DestTy) == Size && DestTy != ResultTy) { - // Does the size of the allocated type match the number of bytes - // allocated? - // - if (ResultTy == 0) { - ResultTy = DestTy; // Keep note of this for future uses... - } else { - // It's overdefined! We don't know which type to convert to! - return false; - } - } + if (getPointedToComposite(AddOp1->getType())) { // case 1 + PRINT_PEEPHOLE2("add-to-gep1:in", AddOp2, *BI); + } else { + PRINT_PEEPHOLE3("add-to-gep2:in", AddOp1, AddOp2, *BI); } - // If we get this far, we have either found, or not, a type that is cast to - // that is of the same size as the malloc instruction. - if (!ResultTy) return false; + GetElementPtrInst *GEP = new GetElementPtrInst(SrcPtr, Indices, + AddOp2->getName(), BI); - PRINT_PEEPHOLE1("mall-refine:in ", MI); - ReplaceInstWithInst(BB->getInstList(), BI, - MI = new MallocInst(PointerType::get(ResultTy))); - PRINT_PEEPHOLE1("mall-refine:out", MI); + Instruction *NCI = new CastInst(GEP, AddOp1->getType()); + ReplaceInstWithInst(BB->getInstList(), BI, NCI); + PRINT_PEEPHOLE2("add-to-gep:out", GEP, NCI); return true; } - - static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) { - Instruction *I = *BI; - // TODO: replace this with a DCE call - if (I->use_size() == 0 && I->getType() != Type::VoidTy) return false; + Instruction *I = BI; if (CastInst *CI = dyn_cast(I)) { Value *Src = CI->getOperand(0); Instruction *SrcI = dyn_cast(Src); // Nonnull if instr source const Type *DestTy = CI->getType(); - // Check for a cast of the same type as the destination! - if (DestTy == Src->getType()) { + // Peephole optimize the following instruction: + // %V2 = cast %V to + // + // Into: + // + if (DestTy == Src->getType()) { // Check for a cast to same type as src!! PRINT_PEEPHOLE1("cast-of-self-ty", CI); CI->replaceAllUsesWith(Src); if (!Src->hasName() && CI->hasName()) { - string Name = CI->getName(); - CI->setName(""); Src->setName(Name, - BB->getParent()->getSymbolTable()); + std::string Name = CI->getName(); + CI->setName(""); + Src->setName(Name, BB->getParent()->getSymbolTable()); } + + // DCE the instruction now, to avoid having the iterative version of DCE + // have to worry about it. + // + BI = BB->getInstList().erase(BI); + + ++NumCastOfCast; return true; } - // Check for a cast of cast, where no size information is lost... - if (SrcI) - if (CastInst *CSrc = dyn_cast(SrcI)) - if (isReinterpretingCast(CI) + isReinterpretingCast(CSrc) < 2) { - // We can only do c-c elimination if, at most, one cast does a - // reinterpretation of the input data. - // - // If legal, make this cast refer the the original casts argument! - // - PRINT_PEEPHOLE2("cast-cast:in ", CI, CSrc); - CI->setOperand(0, CSrc->getOperand(0)); - PRINT_PEEPHOLE1("cast-cast:out", CI); - return true; - } - // Check to see if it's a cast of an instruction that does not depend on the // specific type of the operands to do it's job. - if (!isReinterpretingCast(CI) && - ExpressionConvertableToType(Src, DestTy)) { - PRINT_PEEPHOLE2("EXPR-CONV:in ", CI, Src); - CI->setOperand(0, ConvertExpressionToType(Src, DestTy)); - BI = BB->begin(); // Rescan basic block. BI might be invalidated. - PRINT_PEEPHOLE2("EXPR-CONV:out", CI, CI->getOperand(0)); - return true; + if (!isReinterpretingCast(CI)) { + ValueTypeCache ConvertedTypes; + + // Check to see if we can convert the source of the cast to match the + // destination type of the cast... + // + ConvertedTypes[CI] = CI->getType(); // Make sure the cast doesn't change + if (ExpressionConvertableToType(Src, DestTy, ConvertedTypes)) { + PRINT_PEEPHOLE3("CAST-SRC-EXPR-CONV:in ", Src, CI, BB->getParent()); + + DEBUG(cerr << "\nCONVERTING SRC EXPR TYPE:\n"); + { // ValueMap must be destroyed before function verified! + ValueMapCache ValueMap; + Value *E = ConvertExpressionToType(Src, DestTy, ValueMap); + + if (Constant *CPV = dyn_cast(E)) + CI->replaceAllUsesWith(CPV); + + PRINT_PEEPHOLE1("CAST-SRC-EXPR-CONV:out", E); + DEBUG(cerr << "DONE CONVERTING SRC EXPR TYPE: \n" << BB->getParent()); + } + + DEBUG(assert(verifyFunction(*BB->getParent()) == false && + "Function broken!")); + BI = BB->begin(); // Rescan basic block. BI might be invalidated. + ++NumExprTreesConv; + return true; + } + + // Check to see if we can convert the users of the cast value to match the + // source type of the cast... + // + ConvertedTypes.clear(); + // Make sure the source doesn't change type + ConvertedTypes[Src] = Src->getType(); + if (ValueConvertableToType(CI, Src->getType(), ConvertedTypes)) { + PRINT_PEEPHOLE3("CAST-DEST-EXPR-CONV:in ", Src, CI, BB->getParent()); + + DEBUG(cerr << "\nCONVERTING EXPR TYPE:\n"); + { // ValueMap must be destroyed before function verified! + ValueMapCache ValueMap; + ConvertValueToNewType(CI, Src, ValueMap); // This will delete CI! + } + + PRINT_PEEPHOLE1("CAST-DEST-EXPR-CONV:out", Src); + DEBUG(cerr << "DONE CONVERTING EXPR TYPE: \n\n" << BB->getParent()); + + DEBUG(assert(verifyFunction(*BB->getParent()) == false && + "Function broken!")); + BI = BB->begin(); // Rescan basic block. BI might be invalidated. + ++NumExprTreesConv; + return true; + } } - } else if (MallocInst *MI = dyn_cast(I)) { - if (PeepholeMallocInst(BB, BI)) return true; + // Otherwise find out it this cast is a cast to a pointer type, which is + // then added to some other pointer, then loaded or stored through. If + // so, convert the add into a getelementptr instruction... + // + if (const PointerType *DestPTy = dyn_cast(DestTy)) { + if (HandleCastToPointer(BI, DestPTy)) { + BI = BB->begin(); // Rescan basic block. BI might be invalidated. + ++NumGEPInstFormed; + return true; + } + } - } else if (StoreInst *SI = dyn_cast(I)) { - Value *Val = SI->getOperand(0); - Value *Pointer = SI->getPtrOperand(); - + // Check to see if we are casting from a structure pointer to a pointer to + // the first element of the structure... to avoid munching other peepholes, + // we only let this happen if there are no add uses of the cast. + // // Peephole optimize the following instructions: - // %t1 = getelementptr {<...>} * %StructPtr, - // store %v, * %t1 + // %t1 = cast {<...>} * %StructPtr to * // - // Into: store %v, {<...>} * %StructPtr, + // Into: %t2 = getelementptr {<...>} * %StructPtr, <0, 0, 0, ...> + // %t1 = cast * %t1 to * // - if (GetElementPtrInst *GEP = dyn_cast(Pointer)) { - PRINT_PEEPHOLE2("gep-store:in", GEP, SI); - ReplaceInstWithInst(BB->getInstList(), BI, - SI = new StoreInst(Val, GEP->getPtrOperand(), - GEP->getIndexVec())); - PRINT_PEEPHOLE1("gep-store:out", SI); - return true; - } + if (const CompositeType *CTy = getPointedToComposite(Src->getType())) + if (const PointerType *DestPTy = dyn_cast(DestTy)) { + + // Loop over uses of the cast, checking for add instructions. If an add + // exists, this is probably a part of a more complex GEP, so we don't + // want to mess around with the cast. + // + bool HasAddUse = false; + for (Value::use_iterator I = CI->use_begin(), E = CI->use_end(); + I != E; ++I) + if (isa(*I) && + cast(*I)->getOpcode() == Instruction::Add) { + HasAddUse = true; break; + } + + // If it doesn't have an add use, check to see if the dest type is + // losslessly convertable to one of the types in the start of the struct + // type. + // + if (!HasAddUse) { + const Type *DestPointedTy = DestPTy->getElementType(); + unsigned Depth = 1; + const CompositeType *CurCTy = CTy; + const Type *ElTy = 0; + + // Build the index vector, full of all zeros + std::vector Indices; + Indices.push_back(ConstantSInt::get(Type::LongTy, 0)); + while (CurCTy && !isa(CurCTy)) { + if (const StructType *CurSTy = dyn_cast(CurCTy)) { + // Check for a zero element struct type... if we have one, bail. + if (CurSTy->getElementTypes().size() == 0) break; + + // Grab the first element of the struct type, which must lie at + // offset zero in the struct. + // + ElTy = CurSTy->getElementTypes()[0]; + } else { + ElTy = cast(CurCTy)->getElementType(); + } + + // Insert a zero to index through this type... + Indices.push_back(Constant::getNullValue(CurCTy->getIndexType())); + + // Did we find what we're looking for? + if (ElTy->isLosslesslyConvertableTo(DestPointedTy)) break; + + // Nope, go a level deeper. + ++Depth; + CurCTy = dyn_cast(ElTy); + ElTy = 0; + } + + // Did we find what we were looking for? If so, do the transformation + if (ElTy) { + PRINT_PEEPHOLE1("cast-for-first:in", CI); + + std::string Name = CI->getName(); CI->setName(""); + + // Insert the new T cast instruction... stealing old T's name + GetElementPtrInst *GEP = new GetElementPtrInst(Src, Indices, + Name, BI); + + // Make the old cast instruction reference the new GEP instead of + // the old src value. + // + CI->setOperand(0, GEP); + + PRINT_PEEPHOLE2("cast-for-first:out", GEP, CI); + ++NumGEPInstFormed; + return true; + } + } + } + + } else if (StoreInst *SI = dyn_cast(I)) { + Value *Val = SI->getOperand(0); + Value *Pointer = SI->getPointerOperand(); // Peephole optimize the following instructions: // %t = cast * %P to * ;; If T1 is losslessly convertable to T2 @@ -535,98 +387,111 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) { // %t = cast %V to // store %t2, * %P // + // Note: This is not taken care of by expr conversion because there might + // not be a cast available for the store to convert the incoming value of. + // This code is basically here to make sure that pointers don't have casts + // if possible. + // if (CastInst *CI = dyn_cast(Pointer)) if (Value *CastSrc = CI->getOperand(0)) // CSPT = CastSrcPointerType - if (PointerType *CSPT = dyn_cast(CastSrc->getType())) - if (losslessCastableTypes(Val->getType(), // convertable types! - CSPT->getValueType()) && - !SI->hasIndices()) { // No subscripts yet! + if (const PointerType *CSPT = dyn_cast(CastSrc->getType())) + // convertable types? + if (Val->getType()->isLosslesslyConvertableTo(CSPT->getElementType())) { PRINT_PEEPHOLE3("st-src-cast:in ", Pointer, Val, SI); // Insert the new T cast instruction... stealing old T's name - CastInst *NCI = new CastInst(Val, CSPT->getValueType(), - CI->getName()); - CI->setName(""); - BI = BB->getInstList().insert(BI, NCI)+1; + std::string Name(CI->getName()); CI->setName(""); + CastInst *NCI = new CastInst(Val, CSPT->getElementType(), + Name, BI); // Replace the old store with a new one! ReplaceInstWithInst(BB->getInstList(), BI, SI = new StoreInst(NCI, CastSrc)); PRINT_PEEPHOLE3("st-src-cast:out", NCI, CastSrc, SI); + ++NumLoadStorePeepholes; return true; } - } else if (LoadInst *LI = dyn_cast(I)) { - Value *Pointer = LI->getPtrOperand(); + Value *Pointer = LI->getOperand(0); + const Type *PtrElType = + cast(Pointer->getType())->getElementType(); // Peephole optimize the following instructions: - // %t1 = getelementptr {<...>} * %StructPtr, - // %V = load * %t1 + // %Val = cast * to * ;; If T1 is losslessly convertable to T2 + // %t = load * %P // - // Into: load {<...>} * %StructPtr, + // Into: + // %t = load * %P + // %Val = cast to // - if (GetElementPtrInst *GEP = dyn_cast(Pointer)) { - PRINT_PEEPHOLE2("gep-load:in", GEP, LI); - ReplaceInstWithInst(BB->getInstList(), BI, - LI = new LoadInst(GEP->getPtrOperand(), - GEP->getIndexVec())); - PRINT_PEEPHOLE1("gep-load:out", LI); - return true; - } + // Note: This is not taken care of by expr conversion because there might + // not be a cast available for the store to convert the incoming value of. + // This code is basically here to make sure that pointers don't have casts + // if possible. + // + if (CastInst *CI = dyn_cast(Pointer)) + if (Value *CastSrc = CI->getOperand(0)) // CSPT = CastSrcPointerType + if (const PointerType *CSPT = dyn_cast(CastSrc->getType())) + // convertable types? + if (PtrElType->isLosslesslyConvertableTo(CSPT->getElementType())) { + PRINT_PEEPHOLE2("load-src-cast:in ", Pointer, LI); + + // Create the new load instruction... loading the pre-casted value + LoadInst *NewLI = new LoadInst(CastSrc, LI->getName(), BI); + + // Insert the new T cast instruction... stealing old T's name + CastInst *NCI = new CastInst(NewLI, LI->getType(), CI->getName()); + + // Replace the old store with a new one! + ReplaceInstWithInst(BB->getInstList(), BI, NCI); + PRINT_PEEPHOLE3("load-src-cast:out", NCI, CastSrc, NewLI); + ++NumLoadStorePeepholes; + return true; + } + } else if (I->getOpcode() == Instruction::Add && isa(I->getOperand(1))) { - // Peephole optimize the following instructions: - // %t1 = cast ulong to {<...>} * - // %t2 = add {<...>} * %SP, %t1 ;; Constant must be 2nd operand - // - // or - // %t1 = cast {<...>}* %SP to int* - // %t5 = cast ulong to int* - // %t2 = add int* %t1, %t5 ;; int is same size as field - // - // Into: %t3 = getelementptr {<...>} * %SP, - // %t2 = cast * %t3 to {<...>}* - // - Value *AddOp1 = I->getOperand(0); - CastInst *AddOp2 = cast(I->getOperand(1)); - ConstPoolUInt *OffsetV = dyn_cast(AddOp2->getOperand(0)); - unsigned Offset = OffsetV ? OffsetV->getValue() : 0; - Value *SrcPtr; // Of type pointer to struct... - const StructType *StructTy; - - if ((StructTy = getPointedToStruct(AddOp1->getType()))) { - SrcPtr = AddOp1; // Handle the first case... - } else if (CastInst *AddOp1c = dyn_cast(AddOp1)) { - SrcPtr = AddOp1c->getOperand(0); // Handle the second case... - StructTy = getPointedToStruct(SrcPtr->getType()); + if (PeepholeOptimizeAddCast(BB, BI, I->getOperand(0), + cast(I->getOperand(1)))) { + ++NumGEPInstFormed; + return true; } - - // Only proceed if we have detected all of our conditions successfully... - if (Offset && StructTy && SrcPtr && Offset < TD.getTypeSize(StructTy)) { - const StructLayout *SL = TD.getStructLayout(StructTy); - vector Offsets; - unsigned ActualOffset = Offset; - const Type *ElTy = getStructOffsetType(StructTy, ActualOffset, Offsets); - - if (getPointedToStruct(AddOp1->getType())) { // case 1 - PRINT_PEEPHOLE2("add-to-gep1:in", AddOp2, I); - } else { - PRINT_PEEPHOLE3("add-to-gep2:in", AddOp1, AddOp2, I); - } - - GetElementPtrInst *GEP = new GetElementPtrInst(SrcPtr, Offsets); - BI = BB->getInstList().insert(BI, GEP)+1; - - assert(Offset-ActualOffset == 0 && - "GEP to middle of element not implemented yet!"); + } else if (CallInst *CI = dyn_cast(I)) { + // If we have a call with all varargs arguments, convert the call to use the + // actual argument types present... + // + const PointerType *PTy = cast(CI->getCalledValue()->getType()); + const FunctionType *FTy = cast(PTy->getElementType()); - ReplaceInstWithInst(BB->getInstList(), BI, - I = new CastInst(GEP, I->getType())); - PRINT_PEEPHOLE2("add-to-gep:out", GEP, I); + // Is the call to a vararg variable with no real parameters? + if (FTy->isVarArg() && FTy->getNumParams() == 0) { + // If so, insert a new cast instruction, casting it to a function type + // that matches the current arguments... + // + std::vector Params; // Parameter types... + for (unsigned i = 1, e = CI->getNumOperands(); i != e; ++i) + Params.push_back(CI->getOperand(i)->getType()); + + FunctionType *NewFT = FunctionType::get(FTy->getReturnType(), + Params, false); + PointerType *NewPFunTy = PointerType::get(NewFT); + + // Create a new cast, inserting it right before the function call... + CastInst *NewCast = new CastInst(CI->getCalledValue(), NewPFunTy, + CI->getCalledValue()->getName(), CI); + + // Create a new call instruction... + CallInst *NewCall = new CallInst(NewCast, + std::vector(CI->op_begin()+1, CI->op_end())); + ++BI; + ReplaceInstWithInst(CI, NewCall); + + ++NumVarargCallChanges; return true; } + } return false; @@ -635,48 +500,83 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) { -static bool DoRaisePass(Method *M) { +static bool DoRaisePass(Function &F) { bool Changed = false; - for (Method::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI) { - BasicBlock *BB = *MI; - BasicBlock::InstListType &BIL = BB->getInstList(); - + for (Function::iterator BB = F.begin(), BBE = F.end(); BB != BBE; ++BB) for (BasicBlock::iterator BI = BB->begin(); BI != BB->end();) { - if (PeepholeOptimize(BB, BI)) + DEBUG(cerr << "Processing: " << *BI); + if (dceInstruction(BI) || doConstantPropogation(BI)) { + Changed = true; + ++NumDCEorCP; + DEBUG(cerr << "***\t\t^^-- Dead code eliminated!\n"); + } else if (PeepholeOptimize(BB, BI)) { Changed = true; - else + } else { ++BI; + } } - } + return Changed; } -// RaisePointerReferences::doit - Raise a method representation to a higher +// RaisePointerReferences::doit - Raise a function representation to a higher // level. // -bool RaisePointerReferences::doit(Method *M) { - if (M->isExternal()) return false; - bool Changed = false; - - while (DoRaisePass(M)) Changed = true; - - // PtrCasts - Keep a mapping between the pointer values (the key of the - // map), and the cast to array pointer (the value) in this map. This is - // used when converting pointer math into array addressing. - // - map PtrCasts; +static bool doRPR(Function &F) { + DEBUG(cerr << "\n\n\nStarting to work on Function '" << F.getName() << "'\n"); - // Insert casts for all incoming pointer values. Keep track of those casts - // and the identified incoming values in the PtrCasts map. + // Insert casts for all incoming pointer pointer values that are treated as + // arrays... // - Changed |= DoInsertArrayCasts(M, PtrCasts); + bool Changed = false, LocalChange; + - // Loop over each incoming pointer variable, replacing indexing arithmetic - // with getelementptr calls. + // If the StartInst option was specified, then Peephole optimize that + // instruction first if it occurs in this function. // - Changed |= reduce_apply_bool(PtrCasts.begin(), PtrCasts.end(), - ptr_fun(DoEliminatePointerArithmetic)); + if (!StartInst.empty()) { + for (Function::iterator BB = F.begin(), BBE = F.end(); BB != BBE; ++BB) + for (BasicBlock::iterator BI = BB->begin(); BI != BB->end(); ++BI) + if (BI->getName() == StartInst) { + bool SavedDebug = DebugFlag; // Save the DEBUG() controlling flag. + DebugFlag = true; // Turn on DEBUG's + Changed |= PeepholeOptimize(BB, BI); + DebugFlag = SavedDebug; // Restore DebugFlag to previous state + } + } + + do { + DEBUG(cerr << "Looping: \n" << F); + + // Iterate over the function, refining it, until it converges on a stable + // state + LocalChange = false; + while (DoRaisePass(F)) LocalChange = true; + Changed |= LocalChange; + + } while (LocalChange); return Changed; } + +namespace { + struct RaisePointerReferences : public FunctionPass { + + // FIXME: constructor should save and use target data here!! + RaisePointerReferences(const TargetData &TD) {} + + virtual bool runOnFunction(Function &F) { return doRPR(F); } + + virtual void getAnalysisUsage(AnalysisUsage &AU) const { + AU.preservesCFG(); + } + }; +} + +Pass *createRaisePointerReferencesPass(const TargetData &TD) { + return new RaisePointerReferences(TD); +} + +static RegisterOpt +X("raise", "Raise Pointer References", createRaisePointerReferencesPass);