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Clean up code, implement array indexing stuff

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llvm-svn: 1340
This commit is contained in:
Chris Lattner 2001-11-26 16:58:14 +00:00
parent a9084f9746
commit 95b74bb24f
1 changed files with 175 additions and 423 deletions
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598
lib/Transforms/LevelRaise.cpp
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@ -2,30 +2,7 @@
// //
// This file implements the 'raising' part of the LevelChange API. This is // 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 // 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. // analyze.
//
// 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 ;;<uint>
// %reg108 = alloca ubyte, uint %reg110 ;;<ubyte*>
// %cast76 = cast ubyte* %reg108 to uint* ;;<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.
// //
//===----------------------------------------------------------------------===// //===----------------------------------------------------------------------===//
@ -43,7 +20,7 @@
#include "llvm/Assembly/Writer.h" #include "llvm/Assembly/Writer.h"
//#define DEBUG_PEEPHOLE_INSTS 1 #define DEBUG_PEEPHOLE_INSTS 1
#ifdef DEBUG_PEEPHOLE_INSTS #ifdef DEBUG_PEEPHOLE_INSTS
#define PRINT_PEEPHOLE(ID, NUM, I) \ #define PRINT_PEEPHOLE(ID, NUM, I) \
@ -68,211 +45,12 @@
// cast instruction would cause the underlying bits to change. // cast instruction would cause the underlying bits to change.
// //
static inline bool isReinterpretingCast(const CastInst *CI) { static inline bool isReinterpretingCast(const CastInst *CI) {
return !losslessCastableTypes(CI->getOperand(0)->getType(), CI->getType()); return!CI->getOperand(0)->getType()->isLosslesslyConvertableTo(CI->getType());
} }
// 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<PointerType>(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<Instruction>(*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<const PointerType>(Inst->getType()))
if (const ArrayType *AT = dyn_cast<const ArrayType>(PT->getValueType()))
if (AT->getElementType() == ThePtrType->getValueType()) {
// Cast already exists! Return the existing one!
CastResult = cast<CastInst>(Inst);
return false; // No changes made to program though...
}
break;
}
}
if (!InsertCast) return false; // There is no reason to insert a cast!
// Insert a cast!
const Type *ElTy = ThePtrType->getValueType();
const PointerType *DestTy = PointerType::get(ArrayType::get(ElTy));
CastResult = new CastInst(V, DestTy);
BB->getInstList().insert(InsertBefore, CastResult);
//cerr << "Inserted cast: " << CastResult;
return true; // Made a change!
}
// 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<Value*, CastInst*> &PtrCasts) {
assert(!M->isExternal() && "Can't handle external methods!");
// 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...
}
if (TheCast) // Is there a cast associated with this value?
PtrCasts[*AI] = TheCast; // Yes, add it to the map...
}
// 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;
}
// DoElminatePointerArithmetic - Loop over each incoming pointer variable,
// replacing indexing arithmetic with getelementptr calls.
//
static bool DoEliminatePointerArithmetic(const pair<Value*, CastInst*> &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<Instruction>(*I);
if (Inst->getOpcode() != Instruction::Add)
continue; // We only care about add instructions
BinaryOperator *Add = cast<BinaryOperator>(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 <constant>'
// 2. The only users of the malloc are cast & add 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.
//
// If these conditions hold, we convert the malloc to allocate an [RTy]
// element. This should be extended in the future to handle arrays. TODO
//
static bool PeepholeMallocInst(BasicBlock *BB, BasicBlock::iterator &BI) {
MallocInst *MI = cast<MallocInst>(*BI);
if (!MI->isArrayAllocation()) return false; // No array allocation?
ConstPoolUInt *Amt = dyn_cast<ConstPoolUInt>(MI->getArraySize());
if (Amt == 0 || MI->getAllocatedType() != ArrayType::get(Type::SByteTy))
return false;
// Get the number of bytes allocated...
unsigned Size = Amt->getValue();
const Type *ResultTy = 0;
// 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 (CastInst *CI = dyn_cast<CastInst>(*I)) {
//cerr << "\t" << CI;
// We only work on casts to pointer types for sure, be conservative
if (!isa<PointerType>(CI->getType())) {
cerr << "Found cast of malloc value to non pointer type:\n" << CI;
return false;
}
const Type *DestTy = cast<PointerType>(CI->getType())->getValueType();
if (isa<ArrayType>(DestTy)) {
cerr << "Avoided malloc conversion because of type: " << DestTy
<< " TODO.\n";
return false;
}
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 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;
// Now we check to see if we can convert the return value of malloc to the
// specified pointer type. All this is moot if we can't.
//
ValueTypeCache ConvertedTypes;
if (RetValConvertableToType(MI, PointerType::get(ResultTy), ConvertedTypes)) {
// Yup, it's convertable, do the transformation now!
PRINT_PEEPHOLE1("mall-refine:in ", MI);
// Create a new malloc instruction, and insert it into the method...
MallocInst *NewMI = new MallocInst(PointerType::get(ResultTy));
NewMI->setName(MI->getName());
MI->setName("");
BI = BB->getInstList().insert(BI, NewMI)+1;
// Create a new cast instruction to cast it to the old type...
CastInst *NewCI = new CastInst(NewMI, MI->getType());
BB->getInstList().insert(BI, NewCI);
// Move all users of the old malloc instruction over to use the new cast...
MI->replaceAllUsesWith(NewCI);
ValueMapCache ValueMap;
ConvertUsersType(NewCI, NewMI, ValueMap); // This will delete MI!
BI = BB->begin(); // Rescan basic block. BI might be invalidated.
PRINT_PEEPHOLE1("mall-refine:out", NewMI);
return true;
}
return false;
}
// Peephole optimize the following instructions: // Peephole optimize the following instructions:
// %t1 = cast ulong <const int> to {<...>} * // %t1 = cast ulong <const int> to {<...>} *
@ -288,172 +66,41 @@ static bool PeepholeMallocInst(BasicBlock *BB, BasicBlock::iterator &BI) {
// //
static bool PeepholeOptimizeAddCast(BasicBlock *BB, BasicBlock::iterator &BI, static bool PeepholeOptimizeAddCast(BasicBlock *BB, BasicBlock::iterator &BI,
Value *AddOp1, CastInst *AddOp2) { Value *AddOp1, CastInst *AddOp2) {
Value *OffsetVal = AddOp2->getOperand(0); const CompositeType *CompTy;
Value *SrcPtr; // Of type pointer to struct... Value *OffsetVal = AddOp2->getOperand(0);
const StructType *StructTy; Value *SrcPtr; // Of type pointer to struct...
if ((StructTy = getPointedToStruct(AddOp1->getType()))) { if ((CompTy = getPointedToComposite(AddOp1->getType()))) {
SrcPtr = AddOp1; // Handle the first case... SrcPtr = AddOp1; // Handle the first case...
} else if (CastInst *AddOp1c = dyn_cast<CastInst>(AddOp1)) { } else if (CastInst *AddOp1c = dyn_cast<CastInst>(AddOp1)) {
SrcPtr = AddOp1c->getOperand(0); // Handle the second case... SrcPtr = AddOp1c->getOperand(0); // Handle the second case...
StructTy = getPointedToStruct(SrcPtr->getType()); CompTy = getPointedToComposite(SrcPtr->getType());
} }
// Only proceed if we have detected all of our conditions successfully... // Only proceed if we have detected all of our conditions successfully...
if (!StructTy || !SrcPtr || !OffsetVal->getType()->isIntegral()) if (!CompTy || !SrcPtr || !OffsetVal->getType()->isIntegral())
return false; return false;
// See if the cast is of an integer expression that is either a constant, vector<Value*> Indices;
// or a value scaled by some amount with a possible offset. if (!ConvertableToGEP(SrcPtr->getType(), OffsetVal, Indices, &BI))
// return false; // Not convertable... perhaps next time
analysis::ExprType Expr = analysis::ClassifyExpression(OffsetVal);
unsigned Offset = 0, Scale = 1;
// The expression must either be a constant, or a scaled index to be useful if (getPointedToComposite(AddOp1->getType())) { // case 1
if (!Expr.Offset && !Expr.Scale)
return false;
// Get the offset value if it exists...
if (Expr.Offset) {
if (ConstPoolSInt *CPSI = dyn_cast<ConstPoolSInt>(Expr.Offset))
Offset = (unsigned)CPSI->getValue();
else {
ConstPoolUInt *CPUI = cast<ConstPoolUInt>(Expr.Offset);
Offset = (unsigned)CPUI->getValue();
}
assert(Offset != 0 && "Expression analysis failure!");
}
// Get the scale value if it exists...
if (Expr.Scale) {
if (ConstPoolSInt *CPSI = dyn_cast<ConstPoolSInt>(Expr.Scale))
Scale = (unsigned)CPSI->getValue();
else {
ConstPoolUInt *CPUI = cast<ConstPoolUInt>(Expr.Scale);
Scale = (unsigned)CPUI->getValue();
}
assert(Scale != 1 && "Expression analysis failure!");
}
// Check to make sure the offset is not negative or really large, outside the
// scope of this structure...
//
if (Offset >= TD.getTypeSize(StructTy))
return false;
const StructLayout *SL = TD.getStructLayout(StructTy);
vector<ConstPoolVal*> Offsets;
unsigned ActualOffset = Offset;
const Type *ElTy = getStructOffsetType(StructTy, ActualOffset, Offsets);
if (getPointedToStruct(AddOp1->getType())) { // case 1
PRINT_PEEPHOLE2("add-to-gep1:in", AddOp2, *BI); PRINT_PEEPHOLE2("add-to-gep1:in", AddOp2, *BI);
} else { } else {
PRINT_PEEPHOLE3("add-to-gep2:in", AddOp1, AddOp2, *BI); PRINT_PEEPHOLE3("add-to-gep2:in", AddOp1, AddOp2, *BI);
} }
GetElementPtrInst *GEP = new GetElementPtrInst(SrcPtr, Offsets); GetElementPtrInst *GEP = new GetElementPtrInst(SrcPtr, Indices,
//AddOp2->getName()); AddOp2->getName());
BI = BB->getInstList().insert(BI, GEP)+1; BI = BB->getInstList().insert(BI, GEP)+1;
Instruction *AddrSrc = GEP;
if (const ArrayType *AT = dyn_cast<ArrayType>(ElTy)) {
assert((Scale == 1 || Offset == ActualOffset) &&
"Cannot handle scaled expression and unused offset in the same "
"instruction until after GEP array works!");
// Check to see if we have bottomed out INSIDE of an array reference.. Instruction *NCI = new CastInst(GEP, AddOp1->getType());
//
if (Offset != ActualOffset) {
// Insert a cast of the "rest" of the offset to the appropriate
// pointer type.
CastInst *OffInst =
new CastInst(ConstPoolUInt::get(Type::ULongTy,
Offset-ActualOffset),
GEP->getType());
BI = BB->getInstList().insert(BI, OffInst)+1;
// Now insert an ADD to actually adjust the pointer...
Instruction *AddInst =
BinaryOperator::create(Instruction::Add, GEP, OffInst);
BI = BB->getInstList().insert(BI, AddInst)+1;
PRINT_PEEPHOLE2("add-to-gep:out1", OffInst, AddInst);
AddrSrc = AddInst;
} else if (Scale != 1) {
// If the scale factor occurs, then this means that there is an index into
// this element of the array. Check to make sure the scale factor is the
// same as the size of the datatype that we are dealing with.
//
assert(Scale == TD.getTypeSize(AT->getElementType()) &&
"Scaling by something other than the array element size!!");
// TODO: In the future, we will not want to cast the index and scale to
// pointer types first. We will want to create a GEP directly here.
// Now we must actually perform the scaling operation to get an
// appropriate value to add in... but the scale has to be done in the
// appropriate destination pointer type, so cast the index value now.
//
// Cast the base index pointer
CastInst *IdxValue = new CastInst(Expr.Var, GEP->getType());
BI = BB->getInstList().insert(BI, IdxValue)+1;
// Case the scale amount as well...
CastInst *ScaleAmt =
new CastInst(ConstPoolUInt::get(Type::ULongTy, Scale), GEP->getType());
BI = BB->getInstList().insert(BI, ScaleAmt)+1;
// Insert the multiply now. Make sure to make the constant the second arg
Instruction *ScaledVal =
BinaryOperator::create(Instruction::Mul, IdxValue, ScaleAmt);
BI = BB->getInstList().insert(BI, ScaledVal)+1;
// Now insert an ADD to actually adjust the pointer...
Instruction *AddInst =
BinaryOperator::create(Instruction::Add, GEP, ScaledVal);
BI = BB->getInstList().insert(BI, AddInst)+1;
PRINT_PEEPHOLE4("add-to-gep:out1", IdxValue, ScaleAmt, ScaledVal,
AddInst);
AddrSrc = AddInst;
}
// Insert a cast of the pointer to array of X to be a pointer to the
// element of the array.
//
// Insert a cast of the "rest" of the offset to the appropriate
// pointer type.
CastInst *ACI = new CastInst(AddrSrc, AT->getElementType());
BI = BB->getInstList().insert(BI, ACI)+1;
AddrSrc = ACI;
} else {
assert(Offset == ActualOffset && "GEP to middle of non array!");
assert(Scale == 1 && "Scale factor for expr that is not an array idx!");
}
Instruction *NCI = new CastInst(AddrSrc, AddOp1->getType());
ReplaceInstWithInst(BB->getInstList(), BI, NCI); ReplaceInstWithInst(BB->getInstList(), BI, NCI);
PRINT_PEEPHOLE2("add-to-gep:out", GEP, NCI); PRINT_PEEPHOLE2("add-to-gep:out", GEP, NCI);
return true; return true;
} }
// Peephole optimize the following instructions:
// %t1 = cast int (uint) * %reg111 to uint (...) *
// %t2 = call uint (...) * %cast111( uint %key )
//
// Into: %t3 = call int (uint) * %reg111( uint %key )
// %t2 = cast int %t3 to uint
//
static bool PeepholeCallInst(BasicBlock *BB, BasicBlock::iterator &BI) {
CallInst *CI = cast<CallInst>(*BI);
return false;
}
static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) { static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
Instruction *I = *BI; Instruction *I = *BI;
@ -502,14 +149,14 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
// specific type of the operands to do it's job. // specific type of the operands to do it's job.
if (!isReinterpretingCast(CI)) { if (!isReinterpretingCast(CI)) {
ValueTypeCache ConvertedTypes; ValueTypeCache ConvertedTypes;
if (RetValConvertableToType(CI, Src->getType(), ConvertedTypes)) { if (ValueConvertableToType(CI, Src->getType(), ConvertedTypes)) {
PRINT_PEEPHOLE2("CAST-DEST-EXPR-CONV:in ", CI, Src); PRINT_PEEPHOLE2("CAST-DEST-EXPR-CONV:in ", Src, CI);
#ifdef DEBUG_PEEPHOLE_INSTS #ifdef DEBUG_PEEPHOLE_INSTS
cerr << "\nCONVERTING EXPR TYPE:\n"; cerr << "\nCONVERTING EXPR TYPE:\n";
#endif #endif
ValueMapCache ValueMap; ValueMapCache ValueMap;
ConvertUsersType(CI, Src, ValueMap); // This will delete CI! ConvertValueToNewType(CI, Src, ValueMap); // This will delete CI!
BI = BB->begin(); // Rescan basic block. BI might be invalidated. BI = BB->begin(); // Rescan basic block. BI might be invalidated.
PRINT_PEEPHOLE1("CAST-DEST-EXPR-CONV:out", Src); PRINT_PEEPHOLE1("CAST-DEST-EXPR-CONV:out", Src);
@ -520,7 +167,7 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
} else { } else {
ConvertedTypes.clear(); ConvertedTypes.clear();
if (ExpressionConvertableToType(Src, DestTy, ConvertedTypes)) { if (ExpressionConvertableToType(Src, DestTy, ConvertedTypes)) {
PRINT_PEEPHOLE2("CAST-SRC-EXPR-CONV:in ", CI, Src); PRINT_PEEPHOLE2("CAST-SRC-EXPR-CONV:in ", Src, CI);
#ifdef DEBUG_PEEPHOLE_INSTS #ifdef DEBUG_PEEPHOLE_INSTS
cerr << "\nCONVERTING SRC EXPR TYPE:\n"; cerr << "\nCONVERTING SRC EXPR TYPE:\n";
@ -552,7 +199,7 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
// %t1 = cast <eltype> * %t1 to <ty> * // %t1 = cast <eltype> * %t1 to <ty> *
// //
#if 1 #if 1
if (const StructType *STy = getPointedToStruct(Src->getType())) if (const CompositeType *CTy = getPointedToComposite(Src->getType()))
if (const PointerType *DestPTy = dyn_cast<PointerType>(DestTy)) { if (const PointerType *DestPTy = dyn_cast<PointerType>(DestTy)) {
// Loop over uses of the cast, checking for add instructions. If an add // Loop over uses of the cast, checking for add instructions. If an add
@ -574,24 +221,34 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
if (!HasAddUse) { if (!HasAddUse) {
const Type *DestPointedTy = DestPTy->getValueType(); const Type *DestPointedTy = DestPTy->getValueType();
unsigned Depth = 1; unsigned Depth = 1;
const StructType *CurSTy = STy; const CompositeType *CurCTy = CTy;
const Type *ElTy = 0; const Type *ElTy = 0;
while (CurSTy) {
// Build the index vector, full of all zeros
vector<Value*> Indices;
while (CurCTy) {
if (const StructType *CurSTy = dyn_cast<StructType>(CurCTy)) {
// Check for a zero element struct type... if we have one, bail.
if (CurSTy->getElementTypes().size() == 0) break;
// Check for a zero element struct type... if we have one, bail. // Grab the first element of the struct type, which must lie at
if (CurSTy->getElementTypes().size() == 0) break; // offset zero in the struct.
//
// Grab the first element of the struct type, which must lie at ElTy = CurSTy->getElementTypes()[0];
// offset zero in the struct. } else {
// ElTy = cast<ArrayType>(CurCTy)->getElementType();
ElTy = CurSTy->getElementTypes()[0]; }
// Insert a zero to index through this type...
Indices.push_back(ConstPoolUInt::get(CurCTy->getIndexType(), 0));
// Did we find what we're looking for? // Did we find what we're looking for?
if (losslessCastableTypes(ElTy, DestPointedTy)) break; if (ElTy->isLosslesslyConvertableTo(DestPointedTy)) break;
// Nope, go a level deeper. // Nope, go a level deeper.
++Depth; ++Depth;
CurSTy = dyn_cast<StructType>(ElTy); CurCTy = dyn_cast<CompositeType>(ElTy);
ElTy = 0; ElTy = 0;
} }
@ -599,10 +256,6 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
if (ElTy) { if (ElTy) {
PRINT_PEEPHOLE1("cast-for-first:in", CI); PRINT_PEEPHOLE1("cast-for-first:in", CI);
// Build the index vector, full of all zeros
vector<ConstPoolVal *> Indices(Depth,
ConstPoolUInt::get(Type::UByteTy,0));
// Insert the new T cast instruction... stealing old T's name // Insert the new T cast instruction... stealing old T's name
GetElementPtrInst *GEP = new GetElementPtrInst(Src, Indices, GetElementPtrInst *GEP = new GetElementPtrInst(Src, Indices,
CI->getName()); CI->getName());
@ -622,12 +275,6 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
#endif #endif
#if 1 #if 1
} else if (MallocInst *MI = dyn_cast<MallocInst>(I)) {
if (PeepholeMallocInst(BB, BI)) return true;
} else if (CallInst *CI = dyn_cast<CallInst>(I)) {
if (PeepholeCallInst(BB, BI)) return true;
} else if (StoreInst *SI = dyn_cast<StoreInst>(I)) { } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
Value *Val = SI->getOperand(0); Value *Val = SI->getOperand(0);
Value *Pointer = SI->getPointerOperand(); Value *Pointer = SI->getPointerOperand();
@ -642,9 +289,8 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
// Append any indices that the store instruction has onto the end of the // Append any indices that the store instruction has onto the end of the
// ones that the GEP is carrying... // ones that the GEP is carrying...
// //
vector<ConstPoolVal*> Indices(GEP->getIndices()); vector<Value*> Indices(GEP->copyIndices());
Indices.insert(Indices.end(), SI->getIndices().begin(), Indices.insert(Indices.end(), SI->idx_begin(), SI->idx_end());
SI->getIndices().end());
PRINT_PEEPHOLE2("gep-store:in", GEP, SI); PRINT_PEEPHOLE2("gep-store:in", GEP, SI);
ReplaceInstWithInst(BB->getInstList(), BI, ReplaceInstWithInst(BB->getInstList(), BI,
@ -665,8 +311,8 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
if (CastInst *CI = dyn_cast<CastInst>(Pointer)) if (CastInst *CI = dyn_cast<CastInst>(Pointer))
if (Value *CastSrc = CI->getOperand(0)) // CSPT = CastSrcPointerType if (Value *CastSrc = CI->getOperand(0)) // CSPT = CastSrcPointerType
if (PointerType *CSPT = dyn_cast<PointerType>(CastSrc->getType())) if (PointerType *CSPT = dyn_cast<PointerType>(CastSrc->getType()))
if (losslessCastableTypes(Val->getType(), // convertable types! // convertable types?
CSPT->getValueType()) && if (Val->getType()->isLosslesslyConvertableTo(CSPT->getValueType()) &&
!SI->hasIndices()) { // No subscripts yet! !SI->hasIndices()) { // No subscripts yet!
PRINT_PEEPHOLE3("st-src-cast:in ", Pointer, Val, SI); PRINT_PEEPHOLE3("st-src-cast:in ", Pointer, Val, SI);
@ -697,9 +343,8 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
// Append any indices that the load instruction has onto the end of the // Append any indices that the load instruction has onto the end of the
// ones that the GEP is carrying... // ones that the GEP is carrying...
// //
vector<ConstPoolVal*> Indices(GEP->getIndices()); vector<Value*> Indices(GEP->copyIndices());
Indices.insert(Indices.end(), LI->getIndices().begin(), Indices.insert(Indices.end(), LI->idx_begin(), LI->idx_end());
LI->getIndices().end());
PRINT_PEEPHOLE2("gep-load:in", GEP, LI); PRINT_PEEPHOLE2("gep-load:in", GEP, LI);
ReplaceInstWithInst(BB->getInstList(), BI, ReplaceInstWithInst(BB->getInstList(), BI,
@ -729,7 +374,8 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
const Type *ElTy = SrcTy ? SrcTy->getValueType() : 0; const Type *ElTy = SrcTy ? SrcTy->getValueType() : 0;
// Make sure that nothing will be lost in the new cast... // Make sure that nothing will be lost in the new cast...
if (SrcTy && losslessCastableTypes(ElTy, LI->getType())) { if (!LI->hasIndices() && SrcTy &&
ElTy->isLosslesslyConvertableTo(LI->getType())) {
PRINT_PEEPHOLE2("CL-LoadCast:in ", CI, LI); PRINT_PEEPHOLE2("CL-LoadCast:in ", CI, LI);
string CName = CI->getName(); CI->setName(""); string CName = CI->getName(); CI->setName("");
@ -785,37 +431,143 @@ static bool DoRaisePass(Method *M) {
} }
// 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(Value *V, BasicBlock *BB,
BasicBlock::iterator InsertBefore) {
const PointerType *ThePtrType = dyn_cast<PointerType>(V->getType());
if (!ThePtrType) return false;
const Type *ElTy = ThePtrType->getValueType();
if (isa<MethodType>(ElTy) || isa<ArrayType>(ElTy)) return false;
unsigned ElementSize = TD.getTypeSize(ElTy);
bool InsertCast = false;
for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) {
Instruction *Inst = cast<Instruction>(*I);
switch (Inst->getOpcode()) {
case Instruction::Cast: // There is already a cast instruction!
if (const PointerType *PT = dyn_cast<const PointerType>(Inst->getType()))
if (const ArrayType *AT = dyn_cast<const ArrayType>(PT->getValueType()))
if (AT->getElementType() == ThePtrType->getValueType()) {
// Cast already exists! Don't mess around with it.
return false; // No changes made to program though...
}
break;
case Instruction::Add: { // Analyze pointer arithmetic...
Value *OtherOp = Inst->getOperand(Inst->getOperand(0) == V);
analysis::ExprType Expr = analysis::ClassifyExpression(OtherOp);
// This looks like array addressing iff:
// A. The constant of the index is larger than the size of the element
// type.
// B. The scale factor is >= the size of the type.
//
if (Expr.Offset && getConstantValue(Expr.Offset) >= (int)ElementSize) // A
InsertCast = true;
if (Expr.Scale && getConstantValue(Expr.Scale) >= (int)ElementSize) // B
InsertCast = true;
break;
}
default: break; // Not an interesting use...
}
}
if (!InsertCast) return false; // There is no reason to insert a cast!
// Calculate the destination pointer type
const PointerType *DestTy = PointerType::get(ArrayType::get(ElTy));
// Check to make sure that all uses of the value can be converted over to use
// the newly typed value.
//
ValueTypeCache ConvertedTypes;
if (!ValueConvertableToType(V, DestTy, ConvertedTypes)) {
cerr << "FAILED to convert types of values for " << V << "\n";
ConvertedTypes.clear();
ValueConvertableToType(V, DestTy, ConvertedTypes);
return false;
}
ConvertedTypes.clear();
// Insert a cast!
CastInst *TheCast =
new CastInst(ConstPoolVal::getNullConstant(V->getType()), DestTy,
V->getName());
BB->getInstList().insert(InsertBefore, TheCast);
cerr << "Inserting cast for " << V << endl;
// Convert users of the old value over to use the cast result...
ValueMapCache VMC;
ConvertValueToNewType(V, TheCast, VMC);
// The cast is the only thing that is allowed to reference the value...
TheCast->setOperand(0, V);
cerr << "Inserted ptr-array cast: " << TheCast;
return true; // Made a change!
}
// 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, or a pointer returned from a function call.
//
static bool DoInsertArrayCasts(Method *M) {
assert(!M->isExternal() && "Can't handle external methods!");
// Insert casts for all arguments to the function...
bool Changed = false;
BasicBlock *CurBB = M->front();
for (Method::ArgumentListType::iterator AI = M->getArgumentList().begin(),
AE = M->getArgumentList().end(); AI != AE; ++AI) {
Changed |= DoInsertArrayCast(*AI, CurBB, CurBB->begin());
}
// 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;
}
// RaisePointerReferences::doit - Raise a method representation to a higher // RaisePointerReferences::doit - Raise a method representation to a higher
// level. // level.
// //
bool RaisePointerReferences::doit(Method *M) { bool RaisePointerReferences::doit(Method *M) {
if (M->isExternal()) return false; if (M->isExternal()) return false;
bool Changed = false;
#ifdef DEBUG_PEEPHOLE_INSTS #ifdef DEBUG_PEEPHOLE_INSTS
cerr << "\n\n\nStarting to work on Method '" << M->getName() << "'\n"; cerr << "\n\n\nStarting to work on Method '" << M->getName() << "'\n";
#endif #endif
while (DoRaisePass(M)) Changed = true; // Insert casts for all incoming pointer pointer values that are treated as
// arrays...
#if 0
// 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<Value*, CastInst*> PtrCasts;
// Insert casts for all incoming pointer values. Keep track of those casts
// and the identified incoming values in the PtrCasts map.
// //
Changed |= DoInsertArrayCasts(M, PtrCasts); bool Changed = false, LocalChange;
do {
LocalChange = DoInsertArrayCasts(M);
// Loop over each incoming pointer variable, replacing indexing arithmetic // Iterate over the method, refining it, until it converges on a stable
// with getelementptr calls. // state
// while (DoRaisePass(M)) LocalChange = true;
Changed |= reduce_apply_bool(PtrCasts.begin(), PtrCasts.end(), Changed |= LocalChange;
ptr_fun(DoEliminatePointerArithmetic));
#endif } while (LocalChange);
return Changed; return Changed;
} }