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Handle more complex array indexing expressions

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llvm-svn: 1424
This commit is contained in:
Chris Lattner 2001-12-05 19:41:16 +00:00
parent 662a17ba5f
commit 8ca0f9efd6
1 changed files with 48 additions and 15 deletions
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63
lib/Transforms/TransformInternals.cpp
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@ -180,26 +180,59 @@ const Type *ConvertableToGEP(const Type *Ty, Value *OffsetVal,
unsigned ElSize = TD.getTypeSize(ElTy);
// See if the user is indexing into a different cell of this array...
if (Offset >= ElSize) {
if (Scale && Scale >= ElSize) {
// A scale n*ElSize might occur if we are not stepping through
// array by one. In this case, we will have to insert math to munge
// the index.
//
unsigned ScaleAmt = Scale/ElSize;
if (Scale-ScaleAmt*ElSize)
return 0; // Didn't scale by a multiple of element size, bail out
Scale = ElSize;
unsigned Index = Offset/ElSize; // is zero unless Offset > ElSize
Offset -= Index*ElSize; // Consume part of the offset
if (BI) { // Generate code?
BasicBlock *BB = (**BI)->getParent();
if (Expr.Var->getType() != Type::UIntTy) {
CastInst *IdxCast = new CastInst(Expr.Var, Type::UIntTy);
if (Expr.Var->hasName())
IdxCast->setName(Expr.Var->getName()+"-idxcast");
*BI = BB->getInstList().insert(*BI, IdxCast)+1;
Expr.Var = IdxCast;
}
if (Scale > ElSize) { // If we have to scale up our index, do so now
Value *ScaleAmtVal = ConstantUInt::get(Type::UIntTy, ScaleAmt);
Instruction *Scaler = BinaryOperator::create(Instruction::Mul,
Expr.Var,ScaleAmtVal);
if (Expr.Var->hasName())
Scaler->setName(Expr.Var->getName()+"-scale");
*BI = BB->getInstList().insert(*BI, Scaler)+1;
Expr.Var = Scaler;
}
if (Index) { // Add an offset to the index
Value *IndexAmt = ConstantUInt::get(Type::UIntTy, Index);
Instruction *Offseter = BinaryOperator::create(Instruction::Add,
Expr.Var, IndexAmt);
if (Expr.Var->hasName())
Offseter->setName(Expr.Var->getName()+"-offset");
*BI = BB->getInstList().insert(*BI, Offseter)+1;
Expr.Var = Offseter;
}
}
Indices.push_back(Expr.Var);
Scale = 0; // Consume scale factor!
} else if (Offset >= ElSize) {
// Calculate the index that we are entering into the array cell with
unsigned Index = Offset/ElSize;
Indices.push_back(ConstantUInt::get(Type::UIntTy, Index));
Offset -= Index*ElSize; // Consume part of the offset
} else if (Scale && Scale != 1) {
// Must be indexing into this element with a variable...
if (Scale != ElSize)
return 0; // Type must not be finished yet...
if (Expr.Var->getType() != Type::UIntTy && BI) {
BasicBlock *BB = (**BI)->getParent();
CastInst *IdxCast = new CastInst(Expr.Var, Type::UIntTy);
*BI = BB->getInstList().insert(*BI, IdxCast)+1;
Expr.Var = IdxCast;
}
Indices.push_back(Expr.Var);
Scale = 0; // Consume scale factor!
} else {
// Must be indexing a small amount into the first cell of the array
// Just index into element zero of the array here.