namespace {
struct SROA : public FunctionPass {
static char ID; // Pass identification, replacement for typeid
- explicit SROA(signed T = -1) : FunctionPass(&ID) {
+ explicit SROA(signed T = -1) : FunctionPass(ID) {
if (T == -1)
SRThreshold = 128;
else
}
char SROA::ID = 0;
-static RegisterPass<SROA> X("scalarrepl", "Scalar Replacement of Aggregates");
+INITIALIZE_PASS(SROA, "scalarrepl",
+ "Scalar Replacement of Aggregates", false, false);
// Public interface to the ScalarReplAggregates pass
FunctionPass *llvm::createScalarReplAggregatesPass(signed int Threshold) {
//===----------------------------------------------------------------------===//
namespace {
-/// ConvertToScalarInfo - This struct is used by CanConvertToScalar
+/// ConvertToScalarInfo - This class implements the "Convert To Scalar"
+/// optimization, which scans the uses of an alloca and determines if it can
+/// rewrite it in terms of a single new alloca that can be mem2reg'd.
class ConvertToScalarInfo {
/// AllocaSize - The size of the alloca being considered.
unsigned AllocaSize;
const TargetData &TD;
+ /// IsNotTrivial - This is set to true if there is some access to the object
+ /// which means that mem2reg can't promote it.
bool IsNotTrivial;
+
+ /// VectorTy - This tracks the type that we should promote the vector to if
+ /// it is possible to turn it into a vector. This starts out null, and if it
+ /// isn't possible to turn into a vector type, it gets set to VoidTy.
const Type *VectorTy;
+
+ /// HadAVector - True if there is at least one vector access to the alloca.
+ /// We don't want to turn random arrays into vectors and use vector element
+ /// insert/extract, but if there are element accesses to something that is
+ /// also declared as a vector, we do want to promote to a vector.
bool HadAVector;
public:
HadAVector = false;
}
- AllocaInst *TryConvert(AllocaInst *AI) {
- // If we can't convert this scalar, or if mem2reg can trivially do it, bail
- // out.
- if (!CanConvertToScalar(AI, 0) || !IsNotTrivial)
- // FIXME: In the trivial case, just use mem2reg.
- return 0;
-
- // If we were able to find a vector type that can handle this with
- // insert/extract elements, and if there was at least one use that had
- // a vector type, promote this to a vector. We don't want to promote
- // random stuff that doesn't use vectors (e.g. <9 x double>) because then
- // we just get a lot of insert/extracts. If at least one vector is
- // involved, then we probably really do have a union of vector/array.
- const Type *NewTy;
- if (VectorTy && VectorTy->isVectorTy() && HadAVector) {
- DEBUG(dbgs() << "CONVERT TO VECTOR: " << *AI << "\n TYPE = "
- << *VectorTy << '\n');
- NewTy = VectorTy; // Use the vector type.
- } else {
- DEBUG(dbgs() << "CONVERT TO SCALAR INTEGER: " << *AI << "\n");
- // Create and insert the integer alloca.
- NewTy = IntegerType::get(AI->getContext(), AllocaSize*8);
- }
- AllocaInst *NewAI = new AllocaInst(NewTy, 0, "", AI->getParent()->begin());
- ConvertUsesToScalar(AI, NewAI, 0);
- return NewAI;
- }
+ AllocaInst *TryConvert(AllocaInst *AI);
private:
bool CanConvertToScalar(Value *V, uint64_t Offset);
};
} // end anonymous namespace.
-/// MergeInType - Add the 'In' type to the accumulated type (Accum) so far at
-/// the offset specified by Offset (which is specified in bytes).
+/// TryConvert - Analyze the specified alloca, and if it is safe to do so,
+/// rewrite it to be a new alloca which is mem2reg'able. This returns the new
+/// alloca if possible or null if not.
+AllocaInst *ConvertToScalarInfo::TryConvert(AllocaInst *AI) {
+ // If we can't convert this scalar, or if mem2reg can trivially do it, bail
+ // out.
+ if (!CanConvertToScalar(AI, 0) || !IsNotTrivial)
+ return 0;
+
+ // If we were able to find a vector type that can handle this with
+ // insert/extract elements, and if there was at least one use that had
+ // a vector type, promote this to a vector. We don't want to promote
+ // random stuff that doesn't use vectors (e.g. <9 x double>) because then
+ // we just get a lot of insert/extracts. If at least one vector is
+ // involved, then we probably really do have a union of vector/array.
+ const Type *NewTy;
+ if (VectorTy && VectorTy->isVectorTy() && HadAVector) {
+ DEBUG(dbgs() << "CONVERT TO VECTOR: " << *AI << "\n TYPE = "
+ << *VectorTy << '\n');
+ NewTy = VectorTy; // Use the vector type.
+ } else {
+ DEBUG(dbgs() << "CONVERT TO SCALAR INTEGER: " << *AI << "\n");
+ // Create and insert the integer alloca.
+ NewTy = IntegerType::get(AI->getContext(), AllocaSize*8);
+ }
+ AllocaInst *NewAI = new AllocaInst(NewTy, 0, "", AI->getParent()->begin());
+ ConvertUsesToScalar(AI, NewAI, 0);
+ return NewAI;
+}
+
+/// MergeInType - Add the 'In' type to the accumulated vector type (VectorTy)
+/// so far at the offset specified by Offset (which is specified in bytes).
///
/// There are two cases we handle here:
/// 1) A union of vector types of the same size and potentially its elements.
/// into a <4 x float> that uses insert element.
/// 2) A fully general blob of memory, which we turn into some (potentially
/// large) integer type with extract and insert operations where the loads
-/// and stores would mutate the memory.
+/// and stores would mutate the memory. We mark this by setting VectorTy
+/// to VoidTy.
void ConvertToScalarInfo::MergeInType(const Type *In, uint64_t Offset) {
- // Remember if we saw a vector type.
- HadAVector |= In->isVectorTy();
-
+ // If we already decided to turn this into a blob of integer memory, there is
+ // nothing to be done.
if (VectorTy && VectorTy->isVoidTy())
return;
// If the In type is a vector that is the same size as the alloca, see if it
// matches the existing VecTy.
if (const VectorType *VInTy = dyn_cast<VectorType>(In)) {
+ // Remember if we saw a vector type.
+ HadAVector = true;
+
if (VInTy->getBitWidth()/8 == AllocaSize && Offset == 0) {
// If we're storing/loading a vector of the right size, allow it as a
// vector. If this the first vector we see, remember the type so that
- // we know the element size.
+ // we know the element size. If this is a subsequent access, ignore it
+ // even if it is a differing type but the same size. Worst case we can
+ // bitcast the resultant vectors.
if (VectorTy == 0)
VectorTy = VInTy;
return;
}
if (BitCastInst *BCI = dyn_cast<BitCastInst>(User)) {
+ IsNotTrivial = true; // Can't be mem2reg'd.
if (!CanConvertToScalar(BCI, Offset))
return false;
- IsNotTrivial = true;
continue;
}
// See if all uses can be converted.
if (!CanConvertToScalar(GEP, Offset+GEPOffset))
return false;
- IsNotTrivial = true;
+ IsNotTrivial = true; // Can't be mem2reg'd.
continue;
}
// handle it.
if (MemSetInst *MSI = dyn_cast<MemSetInst>(User)) {
// Store of constant value and constant size.
- if (isa<ConstantInt>(MSI->getValue()) &&
- isa<ConstantInt>(MSI->getLength())) {
- IsNotTrivial = true;
- continue;
- }
+ if (!isa<ConstantInt>(MSI->getValue()) ||
+ !isa<ConstantInt>(MSI->getLength()))
+ return false;
+ IsNotTrivial = true; // Can't be mem2reg'd.
+ continue;
}
// If this is a memcpy or memmove into or out of the whole allocation, we
// can handle it like a load or store of the scalar type.
if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(User)) {
- if (ConstantInt *Len = dyn_cast<ConstantInt>(MTI->getLength()))
- if (Len->getZExtValue() == AllocaSize && Offset == 0) {
- IsNotTrivial = true;
- continue;
- }
+ ConstantInt *Len = dyn_cast<ConstantInt>(MTI->getLength());
+ if (Len == 0 || Len->getZExtValue() != AllocaSize || Offset != 0)
+ return false;
+
+ IsNotTrivial = true; // Can't be mem2reg'd.
+ continue;
}
// Otherwise, we cannot handle this!
DeleteDeadInstructions();
AI->eraseFromParent();
- NumReplaced++;
+ ++NumReplaced;
}
/// DeleteDeadInstructions - Erase instructions on the DeadInstrs list,
// that doesn't have anything to do with the alloca that we are promoting. For
// memset, this Value* stays null.
Value *OtherPtr = 0;
- LLVMContext &Context = MI->getContext();
unsigned MemAlignment = MI->getAlignment();
if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) { // memmove/memcopy
if (Inst == MTI->getRawDest())
// If there is an other pointer, we want to convert it to the same pointer
// type as AI has, so we can GEP through it safely.
if (OtherPtr) {
+ unsigned AddrSpace =
+ cast<PointerType>(OtherPtr->getType())->getAddressSpace();
// Remove bitcasts and all-zero GEPs from OtherPtr. This is an
// optimization, but it's also required to detect the corner case where
// OtherPtr may be a bitcast or GEP that currently being rewritten. (This
// function is only called for mem intrinsics that access the whole
// aggregate, so non-zero GEPs are not an issue here.)
- while (1) {
- if (BitCastInst *BC = dyn_cast<BitCastInst>(OtherPtr)) {
- OtherPtr = BC->getOperand(0);
- continue;
- }
- if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(OtherPtr)) {
- // All zero GEPs are effectively bitcasts.
- if (GEP->hasAllZeroIndices()) {
- OtherPtr = GEP->getOperand(0);
- continue;
- }
- }
- break;
- }
+ OtherPtr = OtherPtr->stripPointerCasts();
+
// Copying the alloca to itself is a no-op: just delete it.
if (OtherPtr == AI || OtherPtr == NewElts[0]) {
// This code will run twice for a no-op memcpy -- once for each operand.
return;
}
- if (ConstantExpr *BCE = dyn_cast<ConstantExpr>(OtherPtr))
- if (BCE->getOpcode() == Instruction::BitCast)
- OtherPtr = BCE->getOperand(0);
-
// If the pointer is not the right type, insert a bitcast to the right
// type.
- if (OtherPtr->getType() != AI->getType())
- OtherPtr = new BitCastInst(OtherPtr, AI->getType(), OtherPtr->getName(),
- MI);
+ const Type *NewTy =
+ PointerType::get(AI->getType()->getElementType(), AddrSpace);
+
+ if (OtherPtr->getType() != NewTy)
+ OtherPtr = new BitCastInst(OtherPtr, NewTy, OtherPtr->getName(), MI);
}
// Process each element of the aggregate.
MI);
uint64_t EltOffset;
const PointerType *OtherPtrTy = cast<PointerType>(OtherPtr->getType());
- if (const StructType *ST =
- dyn_cast<StructType>(OtherPtrTy->getElementType())) {
+ const Type *OtherTy = OtherPtrTy->getElementType();
+ if (const StructType *ST = dyn_cast<StructType>(OtherTy)) {
EltOffset = TD->getStructLayout(ST)->getElementOffset(i);
} else {
- const Type *EltTy =
- cast<SequentialType>(OtherPtr->getType())->getElementType();
+ const Type *EltTy = cast<SequentialType>(OtherTy)->getElementType();
EltOffset = TD->getTypeAllocSize(EltTy)*i;
}
// If the stored element is zero (common case), just store a null
// constant.
Constant *StoreVal;
- if (ConstantInt *CI = dyn_cast<ConstantInt>(MI->getOperand(1))) {
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(MI->getArgOperand(1))) {
if (CI->isZero()) {
StoreVal = Constant::getNullValue(EltTy); // 0.0, null, 0, <0,0>
} else {
}
// Convert the integer value to the appropriate type.
- StoreVal = ConstantInt::get(Context, TotalVal);
+ StoreVal = ConstantInt::get(CI->getContext(), TotalVal);
if (ValTy->isPointerTy())
StoreVal = ConstantExpr::getIntToPtr(StoreVal, ValTy);
else if (ValTy->isFloatingPointTy())
Value *Ops[] = {
SROADest ? EltPtr : OtherElt, // Dest ptr
SROADest ? OtherElt : EltPtr, // Src ptr
- ConstantInt::get(MI->getOperand(2)->getType(), EltSize), // Size
+ ConstantInt::get(MI->getArgOperand(2)->getType(), EltSize), // Size
// Align
ConstantInt::get(Type::getInt32Ty(MI->getContext()), OtherEltAlign),
MI->getVolatileCst()
} else {
assert(isa<MemSetInst>(MI));
Value *Ops[] = {
- EltPtr, MI->getOperand(1), // Dest, Value,
- ConstantInt::get(MI->getOperand(2)->getType(), EltSize), // Size
+ EltPtr, MI->getArgOperand(1), // Dest, Value,
+ ConstantInt::get(MI->getArgOperand(2)->getType(), EltSize), // Size
Zero, // Align
ConstantInt::get(Type::getInt1Ty(MI->getContext()), 0) // isVolatile
};
SrcField = BinaryOperator::CreateShl(SrcField, ShiftVal, "", LI);
}
- ResultVal = BinaryOperator::CreateOr(SrcField, ResultVal, "", LI);
+ // Don't create an 'or x, 0' on the first iteration.
+ if (!isa<Constant>(ResultVal) ||
+ !cast<Constant>(ResultVal)->isNullValue())
+ ResultVal = BinaryOperator::CreateOr(SrcField, ResultVal, "", LI);
+ else
+ ResultVal = SrcField;
}
// Handle tail padding by truncating the result
projects / oota-llvm.git / blobdiff