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* Support pointer indexing 

* Unsized arrays are a thing of the past, remove DoInsertArrayCast family
* Remove cases were we would get into infinite loops because we would insert a cast
  which would then be removed, inserting a different cast, ad infinitum...
* Remove some code that should be redundant with ExprTypeConvert code

llvm-svn: 1465
This commit is contained in:
Chris Lattner 2001-12-14 16:37:52 +00:00
parent 3e88b44afc
commit b457653c6f
1 changed files with 35 additions and 212 deletions
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247
llvm/lib/Transforms/LevelRaise.cpp
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@ -78,18 +78,6 @@ static bool HandleCastToPointer(BasicBlock::iterator BI,
vector<Value*> Indices;
Value *Src = CI->getOperand(0);
const Type *Result = ConvertableToGEP(DestPTy, Src, Indices, &BI);
const PointerType *UsedType = DestPTy;
// If we fail, check to see if we have an pointer source type that, if
// converted to an unsized array type, would work. In this case, we propogate
// the cast forward to the input of the add instruction.
//
if (Result == 0 && getPointedToComposite(DestPTy) == 0) {
// Make an unsized array and try again...
UsedType = PointerType::get(ArrayType::get(DestPTy->getElementType()));
Result = ConvertableToGEP(UsedType, Src, Indices, &BI);
}
if (Result == 0) return false; // Not convertable...
PRINT_PEEPHOLE2("cast-add-to-gep:in", Src, CI);
@ -109,13 +97,6 @@ static bool HandleCastToPointer(BasicBlock::iterator BI,
BasicBlock::iterator AddIt = find(BB->getInstList().begin(),
BB->getInstList().end(), I);
if (UsedType != DestPTy) {
// Insert a cast of the incoming value to something addressable...
CastInst *C = new CastInst(OtherPtr, UsedType, OtherPtr->getName());
AddIt = BB->getInstList().insert(AddIt, C)+1;
OtherPtr = C;
}
GetElementPtrInst *GEP = new GetElementPtrInst(OtherPtr, Indices);
PRINT_PEEPHOLE1("cast-add-to-gep:i", I);
@ -223,33 +204,14 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
// 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)) {
// Check to see if we can convert the source of the cast to match the
// destination type of the cast...
//
ValueTypeCache ConvertedTypes;
if (ValueConvertableToType(CI, Src->getType(), ConvertedTypes)) {
PRINT_PEEPHOLE2("CAST-DEST-EXPR-CONV:in ", Src, CI);
#ifdef DEBUG_PEEPHOLE_INSTS
cerr << "\nCONVERTING EXPR TYPE:\n";
#endif
ValueMapCache ValueMap;
ConvertValueToNewType(CI, Src, ValueMap); // This will delete CI!
BI = BB->begin(); // Rescan basic block. BI might be invalidated.
PRINT_PEEPHOLE1("CAST-DEST-EXPR-CONV:out", Src);
#ifdef DEBUG_PEEPHOLE_INSTS
cerr << "DONE CONVERTING EXPR TYPE: \n\n";// << BB->getParent();
#endif
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();
ConvertedTypes[CI] = CI->getType(); // Make sure the cast doesn't change
if (ExpressionConvertableToType(Src, DestTy, ConvertedTypes)) {
PRINT_PEEPHOLE2("CAST-SRC-EXPR-CONV:in ", Src, CI);
PRINT_PEEPHOLE3("CAST-SRC-EXPR-CONV:in ", Src, CI, BB->getParent());
#ifdef DEBUG_PEEPHOLE_INSTS
cerr << "\nCONVERTING SRC EXPR TYPE:\n";
@ -262,7 +224,28 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
BI = BB->begin(); // Rescan basic block. BI might be invalidated.
PRINT_PEEPHOLE1("CAST-SRC-EXPR-CONV:out", E);
#ifdef DEBUG_PEEPHOLE_INSTS
cerr << "DONE CONVERTING SRC EXPR TYPE: \n\n";// << BB->getParent();
cerr << "DONE CONVERTING SRC EXPR TYPE: \n" << BB->getParent();
#endif
return true;
}
// Check to see if we can convert the source of the cast to match the
// destination type of the cast...
//
ConvertedTypes.clear();
if (ValueConvertableToType(CI, Src->getType(), ConvertedTypes)) {
PRINT_PEEPHOLE3("CAST-DEST-EXPR-CONV:in ", Src, CI, BB->getParent());
#ifdef DEBUG_PEEPHOLE_INSTS
cerr << "\nCONVERTING EXPR TYPE:\n";
#endif
ValueMapCache ValueMap;
ConvertValueToNewType(CI, Src, ValueMap); // This will delete CI!
BI = BB->begin(); // Rescan basic block. BI might be invalidated.
PRINT_PEEPHOLE1("CAST-DEST-EXPR-CONV:out", Src);
#ifdef DEBUG_PEEPHOLE_INSTS
cerr << "DONE CONVERTING EXPR TYPE: \n\n" << BB->getParent();
#endif
return true;
}
@ -317,8 +300,8 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
// Build the index vector, full of all zeros
vector<Value*> Indices;
while (CurCTy) {
Indices.push_back(ConstantUInt::get(Type::UIntTy, 0));
while (CurCTy && !isa<PointerType>(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;
@ -370,27 +353,6 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
Value *Val = SI->getOperand(0);
Value *Pointer = SI->getPointerOperand();
// Peephole optimize the following instructions:
// %t1 = getelementptr {<...>} * %StructPtr, <element indices>
// store <elementty> %v, <elementty> * %t1
//
// Into: store <elementty> %v, {<...>} * %StructPtr, <element indices>
//
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Pointer)) {
// Append any indices that the store instruction has onto the end of the
// ones that the GEP is carrying...
//
vector<Value*> Indices(GEP->copyIndices());
Indices.insert(Indices.end(), SI->idx_begin(), SI->idx_end());
PRINT_PEEPHOLE2("gep-store:in", GEP, SI);
ReplaceInstWithInst(BB->getInstList(), BI,
SI = new StoreInst(Val, GEP->getPointerOperand(),
Indices));
PRINT_PEEPHOLE1("gep-store:out", SI);
return true;
}
// Peephole optimize the following instructions:
// %t = cast <T1>* %P to <T2> * ;; If T1 is losslessly convertable to T2
// store <T2> %V, <T2>* %t
@ -399,6 +361,11 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
// %t = cast <T2> %V to <T1>
// store <T1> %t2, <T1>* %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<CastInst>(Pointer))
if (Value *CastSrc = CI->getOperand(0)) // CSPT = CastSrcPointerType
if (PointerType *CSPT = dyn_cast<PointerType>(CastSrc->getType()))
@ -420,32 +387,6 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
return true;
}
} else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
#if 0
Value *Pointer = LI->getPointerOperand();
// Peephole optimize the following instructions:
// %t1 = getelementptr {<...>} * %StructPtr, <element indices>
// %V = load <elementty> * %t1
//
// Into: load {<...>} * %StructPtr, <element indices>
//
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Pointer)) {
// Append any indices that the load instruction has onto the end of the
// ones that the GEP is carrying...
//
vector<Value*> Indices(GEP->copyIndices());
Indices.insert(Indices.end(), LI->idx_begin(), LI->idx_end());
PRINT_PEEPHOLE2("gep-load:in", GEP, LI);
ReplaceInstWithInst(BB->getInstList(), BI,
LI = new LoadInst(GEP->getPointerOperand(),
Indices));
PRINT_PEEPHOLE1("gep-load:out", LI);
return true;
}
#endif
} else if (I->getOpcode() == Instruction::Add &&
isa<CastInst>(I->getOperand(1))) {
@ -469,6 +410,9 @@ static bool DoRaisePass(Method *M) {
BasicBlock::InstListType &BIL = BB->getInstList();
for (BasicBlock::iterator BI = BB->begin(); BI != BB->end();) {
#if DEBUG_PEEPHOLE_INSTS
cerr << "Processing: " << *BI;
#endif
if (opt::DeadCodeElimination::dceInstruction(BIL, BI) ||
opt::ConstantPropogation::doConstantPropogation(BB, BI)) {
Changed = true;
@ -487,127 +431,6 @@ 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->getElementType();
if (isa<MethodType>(ElTy) ||
(isa<ArrayType>(ElTy) && cast<ArrayType>(ElTy)->isUnsized()))
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->getElementType()))
if (AT->getElementType() == ThePtrType->getElementType()) {
// 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 << " to " << DestTy << "\n";
ConvertedTypes.clear();
ValueConvertableToType(V, DestTy, ConvertedTypes);
return false;
}
ConvertedTypes.clear();
// Insert a cast!
CastInst *TheCast =
new CastInst(Constant::getNullConstant(V->getType()), DestTy, V->getName());
BB->getInstList().insert(InsertBefore, TheCast);
#ifdef DEBUG_PEEPHOLE_INSTS
cerr << "Inserting cast for " << V << endl;
#endif
// 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);
#ifdef DEBUG_PEEPHOLE_INSTS
cerr << "Inserted ptr-array cast: " << TheCast;
#endif
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.
#ifdef DEBUG_PEEPHOLE_INSTS
if (Changed) cerr << "Inserted casts:\n" << M;
#endif
return Changed;
}
// RaisePointerReferences::doit - Raise a method representation to a higher
// level.
//
@ -627,10 +450,10 @@ bool RaisePointerReferences::doit(Method *M) {
#ifdef DEBUG_PEEPHOLE_INSTS
cerr << "Looping: \n" << M;
#endif
LocalChange = DoInsertArrayCasts(M);
// Iterate over the method, refining it, until it converges on a stable
// state
LocalChange = false;
while (DoRaisePass(M)) LocalChange = true;
Changed |= LocalChange;