const Type *CanConvertToScalar(Value *V, bool &IsNotTrivial);
void ConvertToScalar(AllocationInst *AI, const Type *Ty);
void ConvertUsesToScalar(Value *Ptr, AllocaInst *NewAI, unsigned Offset);
+ Value *ConvertUsesOfLoadToScalar(LoadInst *LI, AllocaInst *NewAI,
+ unsigned Offset);
+ Value *ConvertUsesOfStoreToScalar(StoreInst *SI, AllocaInst *NewAI,
+ unsigned Offset);
static Instruction *isOnlyCopiedFromConstantGlobal(AllocationInst *AI);
};
-
- char SROA::ID = 0;
- RegisterPass<SROA> X("scalarrepl", "Scalar Replacement of Aggregates");
}
+char SROA::ID = 0;
+static RegisterPass<SROA> X("scalarrepl", "Scalar Replacement of Aggregates");
+
// Public interface to the ScalarReplAggregates pass
FunctionPass *llvm::createScalarReplAggregatesPass(signed int Threshold) {
return new SROA(Threshold);
return Changed;
}
+/// getNumSAElements - Return the number of elements in the specific struct or
+/// array.
+static uint64_t getNumSAElements(const Type *T) {
+ if (const StructType *ST = dyn_cast<StructType>(T))
+ return ST->getNumElements();
+ return cast<ArrayType>(T)->getNumElements();
+}
+
// performScalarRepl - This algorithm is a simple worklist driven algorithm,
// which runs on all of the malloc/alloca instructions in the function, removing
// them if they are only used by getelementptr instructions.
(isa<StructType>(AI->getAllocatedType()) ||
isa<ArrayType>(AI->getAllocatedType())) &&
AI->getAllocatedType()->isSized() &&
- TD.getABITypeSize(AI->getAllocatedType()) < SRThreshold) {
+ // Do not promote any struct whose size is larger than "128" bytes.
+ TD.getABITypeSize(AI->getAllocatedType()) < SRThreshold &&
+ // Do not promote any struct into more than "32" separate vars.
+ getNumSAElements(AI->getAllocatedType()) < SRThreshold/4) {
// Check that all of the users of the allocation are capable of being
// transformed.
switch (isSafeAllocaToScalarRepl(AI)) {
continue;
}
+ // Replace:
+ // %res = load { i32, i32 }* %alloc
+ // with:
+ // %load.0 = load i32* %alloc.0
+ // %insert.0 insertvalue { i32, i32 } zeroinitializer, i32 %load.0, 0
+ // %load.1 = load i32* %alloc.1
+ // %insert = insertvalue { i32, i32 } %insert.0, i32 %load.1, 1
+ // (Also works for arrays instead of structs)
+ if (LoadInst *LI = dyn_cast<LoadInst>(User)) {
+ Value *Insert = UndefValue::get(LI->getType());
+ for (unsigned i = 0, e = ElementAllocas.size(); i != e; ++i) {
+ Value *Load = new LoadInst(ElementAllocas[i], "load", LI);
+ Insert = InsertValueInst::Create(Insert, Load, i, "insert", LI);
+ }
+ LI->replaceAllUsesWith(Insert);
+ LI->eraseFromParent();
+ continue;
+ }
+
+ // Replace:
+ // store { i32, i32 } %val, { i32, i32 }* %alloc
+ // with:
+ // %val.0 = extractvalue { i32, i32 } %val, 0
+ // store i32 %val.0, i32* %alloc.0
+ // %val.1 = extractvalue { i32, i32 } %val, 1
+ // store i32 %val.1, i32* %alloc.1
+ // (Also works for arrays instead of structs)
+ if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
+ Value *Val = SI->getOperand(0);
+ for (unsigned i = 0, e = ElementAllocas.size(); i != e; ++i) {
+ Value *Extract = ExtractValueInst::Create(Val, i, Val->getName(), SI);
+ new StoreInst(Extract, ElementAllocas[i], SI);
+ }
+ SI->eraseFromParent();
+ continue;
+ }
+
GetElementPtrInst *GEPI = cast<GetElementPtrInst>(User);
// We now know that the GEP is of the form: GEP <ptr>, 0, <cst>
unsigned Idx =
SmallVector<Value*, 8> NewArgs;
NewArgs.push_back(Constant::getNullValue(Type::Int32Ty));
NewArgs.append(GEPI->op_begin()+3, GEPI->op_end());
- RepValue = new GetElementPtrInst(AllocaToUse, NewArgs.begin(),
- NewArgs.end(), "", GEPI);
+ RepValue = GetElementPtrInst::Create(AllocaToUse, NewArgs.begin(),
+ NewArgs.end(), "", GEPI);
RepValue->takeName(GEPI);
}
if (BitCastInst *C = dyn_cast<BitCastInst>(User))
return isSafeUseOfBitCastedAllocation(C, AI, Info);
+ if (isa<LoadInst>(User))
+ return; // Loads (returning a first class aggregrate) are always rewritable
+
+ if (isa<StoreInst>(User) && User->getOperand(0) != AI)
+ return; // Store is ok if storing INTO the pointer, not storing the pointer
+
GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(User);
if (GEPI == 0)
return MarkUnsafe(Info);
bool IsAllZeroIndices = true;
- // If this is a use of an array allocation, do a bit more checking for sanity.
+ // If the first index is a non-constant index into an array, see if we can
+ // handle it as a special case.
if (const ArrayType *AT = dyn_cast<ArrayType>(*I)) {
- uint64_t NumElements = AT->getNumElements();
-
- if (ConstantInt *Idx = dyn_cast<ConstantInt>(I.getOperand())) {
- IsAllZeroIndices &= Idx->isZero();
-
- // Check to make sure that index falls within the array. If not,
- // something funny is going on, so we won't do the optimization.
- //
- if (Idx->getZExtValue() >= NumElements)
- return MarkUnsafe(Info);
-
- // We cannot scalar repl this level of the array unless any array
- // sub-indices are in-range constants. In particular, consider:
- // A[0][i]. We cannot know that the user isn't doing invalid things like
- // allowing i to index an out-of-range subscript that accesses A[1].
- //
- // Scalar replacing *just* the outer index of the array is probably not
- // going to be a win anyway, so just give up.
- for (++I; I != E && (isa<ArrayType>(*I) || isa<VectorType>(*I)); ++I) {
- uint64_t NumElements;
- if (const ArrayType *SubArrayTy = dyn_cast<ArrayType>(*I))
- NumElements = SubArrayTy->getNumElements();
- else
- NumElements = cast<VectorType>(*I)->getNumElements();
-
- ConstantInt *IdxVal = dyn_cast<ConstantInt>(I.getOperand());
- if (!IdxVal) return MarkUnsafe(Info);
- if (IdxVal->getZExtValue() >= NumElements)
- return MarkUnsafe(Info);
- IsAllZeroIndices &= IdxVal->isZero();
- }
-
- } else {
+ if (!isa<ConstantInt>(I.getOperand())) {
IsAllZeroIndices = 0;
+ uint64_t NumElements = AT->getNumElements();
// If this is an array index and the index is not constant, we cannot
// promote... that is unless the array has exactly one or two elements in
return MarkUnsafe(Info);
}
}
-
+
+
+ // Walk through the GEP type indices, checking the types that this indexes
+ // into.
+ for (; I != E; ++I) {
+ // Ignore struct elements, no extra checking needed for these.
+ if (isa<StructType>(*I))
+ continue;
+
+ // Don't SROA pointers into vectors.
+ if (isa<VectorType>(*I))
+ return MarkUnsafe(Info);
+
+ // Otherwise, we must have an index into an array type. Verify that this is
+ // an in-range constant integer. Specifically, consider A[0][i]. We
+ // cannot know that the user isn't doing invalid things like allowing i to
+ // index an out-of-range subscript that accesses A[1]. Because of this, we
+ // have to reject SROA of any accesses into structs where any of the
+ // components are variables.
+ ConstantInt *IdxVal = dyn_cast<ConstantInt>(I.getOperand());
+ if (!IdxVal) return MarkUnsafe(Info);
+ if (IdxVal->getZExtValue() >= cast<ArrayType>(*I)->getNumElements())
+ return MarkUnsafe(Info);
+
+ IsAllZeroIndices &= IdxVal->isZero();
+ }
+
// If there are any non-simple uses of this getelementptr, make sure to reject
// them.
return isSafeElementUse(GEPI, IsAllZeroIndices, AI, Info);
// If this is a memcpy/memmove, emit a GEP of the other element address.
Value *OtherElt = 0;
if (OtherPtr) {
- Value *Idx[2];
- Idx[0] = Zero;
- Idx[1] = ConstantInt::get(Type::Int32Ty, i);
- OtherElt = new GetElementPtrInst(OtherPtr, Idx, Idx + 2,
- OtherPtr->getNameStr()+"."+utostr(i),
- MI);
+ Value *Idx[2] = { Zero, ConstantInt::get(Type::Int32Ty, i) };
+ OtherElt = GetElementPtrInst::Create(OtherPtr, Idx, Idx + 2,
+ OtherPtr->getNameStr()+"."+utostr(i),
+ MI);
}
Value *EltPtr = NewElts[i];
const Type *EltTy =cast<PointerType>(EltPtr->getType())->getElementType();
// If we got down to a scalar, insert a load or store as appropriate.
- if (EltTy->isFirstClassType()) {
+ if (EltTy->isSingleValueType()) {
if (isa<MemCpyInst>(MI) || isa<MemMoveInst>(MI)) {
Value *Elt = new LoadInst(SROADest ? OtherElt : EltPtr, "tmp",
MI);
ConstantInt::get(MI->getOperand(3)->getType(), EltSize), // Size
Zero // Align
};
- new CallInst(TheFn, Ops, Ops + 4, "", MI);
+ CallInst::Create(TheFn, Ops, Ops + 4, "", MI);
} else {
assert(isa<MemSetInst>(MI));
Value *Ops[] = {
ConstantInt::get(MI->getOperand(3)->getType(), EltSize), // Size
Zero // Align
};
- new CallInst(TheFn, Ops, Ops + 4, "", MI);
+ CallInst::Create(TheFn, Ops, Ops + 4, "", MI);
}
}
/// HasPadding - Return true if the specified type has any structure or
/// alignment padding, false otherwise.
-static bool HasPadding(const Type *Ty, const TargetData &TD,
- bool inPacked = false) {
+static bool HasPadding(const Type *Ty, const TargetData &TD) {
if (const StructType *STy = dyn_cast<StructType>(Ty)) {
const StructLayout *SL = TD.getStructLayout(STy);
unsigned PrevFieldBitOffset = 0;
unsigned FieldBitOffset = SL->getElementOffsetInBits(i);
// Padding in sub-elements?
- if (HasPadding(STy->getElementType(i), TD, STy->isPacked()))
+ if (HasPadding(STy->getElementType(i), TD))
return true;
// Check to see if there is any padding between this element and the
}
} else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
- return HasPadding(ATy->getElementType(), TD, false);
+ return HasPadding(ATy->getElementType(), TD);
} else if (const VectorType *VTy = dyn_cast<VectorType>(Ty)) {
- return HasPadding(VTy->getElementType(), TD, false);
+ return HasPadding(VTy->getElementType(), TD);
}
- return inPacked ?
- false : TD.getTypeSizeInBits(Ty) != TD.getABITypeSizeInBits(Ty);
+ return TD.getTypeSizeInBits(Ty) != TD.getABITypeSizeInBits(Ty);
}
/// isSafeStructAllocaToScalarRepl - Check to see if the specified allocation of
// Insert the new GEP instructions, which are properly indexed.
SmallVector<Value*, 8> Indices(GEPI->op_begin()+1, GEPI->op_end());
Indices[1] = Constant::getNullValue(Type::Int32Ty);
- Value *ZeroIdx = new GetElementPtrInst(GEPI->getOperand(0),
- Indices.begin(),
- Indices.end(),
- GEPI->getName()+".0", GEPI);
+ Value *ZeroIdx = GetElementPtrInst::Create(GEPI->getOperand(0),
+ Indices.begin(),
+ Indices.end(),
+ GEPI->getName()+".0", GEPI);
Indices[1] = ConstantInt::get(Type::Int32Ty, 1);
- Value *OneIdx = new GetElementPtrInst(GEPI->getOperand(0),
- Indices.begin(),
- Indices.end(),
- GEPI->getName()+".1", GEPI);
+ Value *OneIdx = GetElementPtrInst::Create(GEPI->getOperand(0),
+ Indices.begin(),
+ Indices.end(),
+ GEPI->getName()+".1", GEPI);
// Replace all loads of the variable index GEP with loads from both
// indexes and a select.
while (!GEPI->use_empty()) {
LoadInst *LI = cast<LoadInst>(GEPI->use_back());
Value *Zero = new LoadInst(ZeroIdx, LI->getName()+".0", LI);
Value *One = new LoadInst(OneIdx , LI->getName()+".1", LI);
- Value *R = new SelectInst(IsOne, One, Zero, LI->getName(), LI);
+ Value *R = SelectInst::Create(IsOne, One, Zero, LI->getName(), LI);
LI->replaceAllUsesWith(R);
LI->eraseFromParent();
}
Instruction *User = cast<Instruction>(*UI);
if (LoadInst *LI = dyn_cast<LoadInst>(User)) {
+ // FIXME: Loads of a first class aggregrate value could be converted to a
+ // series of loads and insertvalues
+ if (!LI->getType()->isSingleValueType())
+ return 0;
+
if (MergeInType(LI->getType(), UsedType, TD))
return 0;
} else if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
// Storing the pointer, not into the value?
if (SI->getOperand(0) == V) return 0;
+
+ // FIXME: Stores of a first class aggregrate value could be converted to a
+ // series of extractvalues and stores
+ if (!SI->getOperand(0)->getType()->isSingleValueType())
+ return 0;
// NOTE: We could handle storing of FP imms into integers here!
/// Offset is an offset from the original alloca, in bits that need to be
/// shifted to the right. By the end of this, there should be no uses of Ptr.
void SROA::ConvertUsesToScalar(Value *Ptr, AllocaInst *NewAI, unsigned Offset) {
- const TargetData &TD = getAnalysis<TargetData>();
while (!Ptr->use_empty()) {
Instruction *User = cast<Instruction>(Ptr->use_back());
if (LoadInst *LI = dyn_cast<LoadInst>(User)) {
- // The load is a bit extract from NewAI shifted right by Offset bits.
- Value *NV = new LoadInst(NewAI, LI->getName(), LI);
- if (NV->getType() == LI->getType() && Offset == 0) {
- // We win, no conversion needed.
- } else if (const VectorType *PTy = dyn_cast<VectorType>(NV->getType())) {
- // If the result alloca is a vector type, this is either an element
- // access or a bitcast to another vector type.
- if (isa<VectorType>(LI->getType())) {
- NV = new BitCastInst(NV, LI->getType(), LI->getName(), LI);
- } else {
- // Must be an element access.
- unsigned Elt = Offset/TD.getABITypeSizeInBits(PTy->getElementType());
- NV = new ExtractElementInst(
- NV, ConstantInt::get(Type::Int32Ty, Elt), "tmp", LI);
- }
- } else if (isa<PointerType>(NV->getType())) {
- assert(isa<PointerType>(LI->getType()));
- // Must be ptr->ptr cast. Anything else would result in NV being
- // an integer.
- NV = new BitCastInst(NV, LI->getType(), LI->getName(), LI);
- } else {
- const IntegerType *NTy = cast<IntegerType>(NV->getType());
-
- // If this is a big-endian system and the load is narrower than the
- // full alloca type, we need to do a shift to get the right bits.
- int ShAmt = 0;
- if (TD.isBigEndian()) {
- // On big-endian machines, the lowest bit is stored at the bit offset
- // from the pointer given by getTypeStoreSizeInBits. This matters for
- // integers with a bitwidth that is not a multiple of 8.
- ShAmt = TD.getTypeStoreSizeInBits(NTy) -
- TD.getTypeStoreSizeInBits(LI->getType()) - Offset;
- } else {
- ShAmt = Offset;
- }
-
- // Note: we support negative bitwidths (with shl) which are not defined.
- // We do this to support (f.e.) loads off the end of a structure where
- // only some bits are used.
- if (ShAmt > 0 && (unsigned)ShAmt < NTy->getBitWidth())
- NV = BinaryOperator::createLShr(NV,
- ConstantInt::get(NV->getType(),ShAmt),
- LI->getName(), LI);
- else if (ShAmt < 0 && (unsigned)-ShAmt < NTy->getBitWidth())
- NV = BinaryOperator::createShl(NV,
- ConstantInt::get(NV->getType(),-ShAmt),
- LI->getName(), LI);
-
- // Finally, unconditionally truncate the integer to the right width.
- unsigned LIBitWidth = TD.getTypeSizeInBits(LI->getType());
- if (LIBitWidth < NTy->getBitWidth())
- NV = new TruncInst(NV, IntegerType::get(LIBitWidth),
- LI->getName(), LI);
-
- // If the result is an integer, this is a trunc or bitcast.
- if (isa<IntegerType>(LI->getType())) {
- assert(NV->getType() == LI->getType() && "Truncate wasn't enough?");
- } else if (LI->getType()->isFloatingPoint()) {
- // Just do a bitcast, we know the sizes match up.
- NV = new BitCastInst(NV, LI->getType(), LI->getName(), LI);
- } else {
- // Otherwise must be a pointer.
- NV = new IntToPtrInst(NV, LI->getType(), LI->getName(), LI);
- }
- }
+ Value *NV = ConvertUsesOfLoadToScalar(LI, NewAI, Offset);
LI->replaceAllUsesWith(NV);
LI->eraseFromParent();
} else if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
assert(SI->getOperand(0) != Ptr && "Consistency error!");
- // Convert the stored type to the actual type, shift it left to insert
- // then 'or' into place.
- Value *SV = SI->getOperand(0);
- const Type *AllocaType = NewAI->getType()->getElementType();
- if (SV->getType() == AllocaType) {
- // All is well.
- } else if (const VectorType *PTy = dyn_cast<VectorType>(AllocaType)) {
- Value *Old = new LoadInst(NewAI, NewAI->getName()+".in", SI);
-
- // If the result alloca is a vector type, this is either an element
- // access or a bitcast to another vector type.
- if (isa<VectorType>(SV->getType())) {
- SV = new BitCastInst(SV, AllocaType, SV->getName(), SI);
- } else {
- // Must be an element insertion.
- unsigned Elt = Offset/TD.getABITypeSizeInBits(PTy->getElementType());
- SV = new InsertElementInst(Old, SV,
- ConstantInt::get(Type::Int32Ty, Elt),
- "tmp", SI);
- }
- } else if (isa<PointerType>(AllocaType)) {
- // If the alloca type is a pointer, then all the elements must be
- // pointers.
- if (SV->getType() != AllocaType)
- SV = new BitCastInst(SV, AllocaType, SV->getName(), SI);
- } else {
- Value *Old = new LoadInst(NewAI, NewAI->getName()+".in", SI);
-
- // If SV is a float, convert it to the appropriate integer type.
- // If it is a pointer, do the same, and also handle ptr->ptr casts
- // here.
- unsigned SrcWidth = TD.getTypeSizeInBits(SV->getType());
- unsigned DestWidth = TD.getTypeSizeInBits(AllocaType);
- unsigned SrcStoreWidth = TD.getTypeStoreSizeInBits(SV->getType());
- unsigned DestStoreWidth = TD.getTypeStoreSizeInBits(AllocaType);
- if (SV->getType()->isFloatingPoint())
- SV = new BitCastInst(SV, IntegerType::get(SrcWidth),
- SV->getName(), SI);
- else if (isa<PointerType>(SV->getType()))
- SV = new PtrToIntInst(SV, TD.getIntPtrType(), SV->getName(), SI);
-
- // Always zero extend the value if needed.
- if (SV->getType() != AllocaType)
- SV = new ZExtInst(SV, AllocaType, SV->getName(), SI);
-
- // If this is a big-endian system and the store is narrower than the
- // full alloca type, we need to do a shift to get the right bits.
- int ShAmt = 0;
- if (TD.isBigEndian()) {
- // On big-endian machines, the lowest bit is stored at the bit offset
- // from the pointer given by getTypeStoreSizeInBits. This matters for
- // integers with a bitwidth that is not a multiple of 8.
- ShAmt = DestStoreWidth - SrcStoreWidth - Offset;
- } else {
- ShAmt = Offset;
- }
-
- // Note: we support negative bitwidths (with shr) which are not defined.
- // We do this to support (f.e.) stores off the end of a structure where
- // only some bits in the structure are set.
- APInt Mask(APInt::getLowBitsSet(DestWidth, SrcWidth));
- if (ShAmt > 0 && (unsigned)ShAmt < DestWidth) {
- SV = BinaryOperator::createShl(SV,
- ConstantInt::get(SV->getType(), ShAmt),
- SV->getName(), SI);
- Mask <<= ShAmt;
- } else if (ShAmt < 0 && (unsigned)-ShAmt < DestWidth) {
- SV = BinaryOperator::createLShr(SV,
- ConstantInt::get(SV->getType(),-ShAmt),
- SV->getName(), SI);
- Mask = Mask.lshr(ShAmt);
- }
-
- // Mask out the bits we are about to insert from the old value, and or
- // in the new bits.
- if (SrcWidth != DestWidth) {
- assert(DestWidth > SrcWidth);
- Old = BinaryOperator::createAnd(Old, ConstantInt::get(~Mask),
- Old->getName()+".mask", SI);
- SV = BinaryOperator::createOr(Old, SV, SV->getName()+".ins", SI);
- }
- }
+ Value *SV = ConvertUsesOfStoreToScalar(SI, NewAI, Offset);
new StoreInst(SV, NewAI, SI);
SI->eraseFromParent();
}
}
+/// ConvertUsesOfLoadToScalar - Convert all of the users the specified load to
+/// use the new alloca directly, returning the value that should replace the
+/// load. This happens when we are converting an "integer union" to a
+/// single integer scalar, or when we are converting a "vector union" to a
+/// vector with insert/extractelement instructions.
+///
+/// Offset is an offset from the original alloca, in bits that need to be
+/// shifted to the right. By the end of this, there should be no uses of Ptr.
+Value *SROA::ConvertUsesOfLoadToScalar(LoadInst *LI, AllocaInst *NewAI,
+ unsigned Offset) {
+ // The load is a bit extract from NewAI shifted right by Offset bits.
+ Value *NV = new LoadInst(NewAI, LI->getName(), LI);
+
+ if (NV->getType() == LI->getType() && Offset == 0) {
+ // We win, no conversion needed.
+ return NV;
+ }
+
+ // If the result type of the 'union' is a pointer, then this must be ptr->ptr
+ // cast. Anything else would result in NV being an integer.
+ if (isa<PointerType>(NV->getType())) {
+ assert(isa<PointerType>(LI->getType()));
+ return new BitCastInst(NV, LI->getType(), LI->getName(), LI);
+ }
+
+ if (const VectorType *VTy = dyn_cast<VectorType>(NV->getType())) {
+ // If the result alloca is a vector type, this is either an element
+ // access or a bitcast to another vector type.
+ if (isa<VectorType>(LI->getType()))
+ return new BitCastInst(NV, LI->getType(), LI->getName(), LI);
+
+ // Otherwise it must be an element access.
+ const TargetData &TD = getAnalysis<TargetData>();
+ unsigned Elt = 0;
+ if (Offset) {
+ unsigned EltSize = TD.getABITypeSizeInBits(VTy->getElementType());
+ Elt = Offset/EltSize;
+ Offset -= EltSize*Elt;
+ }
+ NV = new ExtractElementInst(NV, ConstantInt::get(Type::Int32Ty, Elt),
+ "tmp", LI);
+
+ // If we're done, return this element.
+ if (NV->getType() == LI->getType() && Offset == 0)
+ return NV;
+ }
+
+ const IntegerType *NTy = cast<IntegerType>(NV->getType());
+
+ // If this is a big-endian system and the load is narrower than the
+ // full alloca type, we need to do a shift to get the right bits.
+ int ShAmt = 0;
+ const TargetData &TD = getAnalysis<TargetData>();
+ if (TD.isBigEndian()) {
+ // On big-endian machines, the lowest bit is stored at the bit offset
+ // from the pointer given by getTypeStoreSizeInBits. This matters for
+ // integers with a bitwidth that is not a multiple of 8.
+ ShAmt = TD.getTypeStoreSizeInBits(NTy) -
+ TD.getTypeStoreSizeInBits(LI->getType()) - Offset;
+ } else {
+ ShAmt = Offset;
+ }
+
+ // Note: we support negative bitwidths (with shl) which are not defined.
+ // We do this to support (f.e.) loads off the end of a structure where
+ // only some bits are used.
+ if (ShAmt > 0 && (unsigned)ShAmt < NTy->getBitWidth())
+ NV = BinaryOperator::CreateLShr(NV,
+ ConstantInt::get(NV->getType(),ShAmt),
+ LI->getName(), LI);
+ else if (ShAmt < 0 && (unsigned)-ShAmt < NTy->getBitWidth())
+ NV = BinaryOperator::CreateShl(NV,
+ ConstantInt::get(NV->getType(),-ShAmt),
+ LI->getName(), LI);
+
+ // Finally, unconditionally truncate the integer to the right width.
+ unsigned LIBitWidth = TD.getTypeSizeInBits(LI->getType());
+ if (LIBitWidth < NTy->getBitWidth())
+ NV = new TruncInst(NV, IntegerType::get(LIBitWidth),
+ LI->getName(), LI);
+
+ // If the result is an integer, this is a trunc or bitcast.
+ if (isa<IntegerType>(LI->getType())) {
+ // Should be done.
+ } else if (LI->getType()->isFloatingPoint()) {
+ // Just do a bitcast, we know the sizes match up.
+ NV = new BitCastInst(NV, LI->getType(), LI->getName(), LI);
+ } else {
+ // Otherwise must be a pointer.
+ NV = new IntToPtrInst(NV, LI->getType(), LI->getName(), LI);
+ }
+ assert(NV->getType() == LI->getType() && "Didn't convert right?");
+ return NV;
+}
+
+
+/// ConvertUsesOfStoreToScalar - Convert the specified store to a load+store
+/// pair of the new alloca directly, returning the value that should be stored
+/// to the alloca. This happens when we are converting an "integer union" to a
+/// single integer scalar, or when we are converting a "vector union" to a
+/// vector with insert/extractelement instructions.
+///
+/// Offset is an offset from the original alloca, in bits that need to be
+/// shifted to the right. By the end of this, there should be no uses of Ptr.
+Value *SROA::ConvertUsesOfStoreToScalar(StoreInst *SI, AllocaInst *NewAI,
+ unsigned Offset) {
+
+ // Convert the stored type to the actual type, shift it left to insert
+ // then 'or' into place.
+ Value *SV = SI->getOperand(0);
+ const Type *AllocaType = NewAI->getType()->getElementType();
+ if (SV->getType() == AllocaType && Offset == 0) {
+ // All is well.
+ } else if (const VectorType *PTy = dyn_cast<VectorType>(AllocaType)) {
+ Value *Old = new LoadInst(NewAI, NewAI->getName()+".in", SI);
+
+ // If the result alloca is a vector type, this is either an element
+ // access or a bitcast to another vector type.
+ if (isa<VectorType>(SV->getType())) {
+ SV = new BitCastInst(SV, AllocaType, SV->getName(), SI);
+ } else {
+ // Must be an element insertion.
+ const TargetData &TD = getAnalysis<TargetData>();
+ unsigned Elt = Offset/TD.getABITypeSizeInBits(PTy->getElementType());
+ SV = InsertElementInst::Create(Old, SV,
+ ConstantInt::get(Type::Int32Ty, Elt),
+ "tmp", SI);
+ }
+ } else if (isa<PointerType>(AllocaType)) {
+ // If the alloca type is a pointer, then all the elements must be
+ // pointers.
+ if (SV->getType() != AllocaType)
+ SV = new BitCastInst(SV, AllocaType, SV->getName(), SI);
+ } else {
+ Value *Old = new LoadInst(NewAI, NewAI->getName()+".in", SI);
+
+ // If SV is a float, convert it to the appropriate integer type.
+ // If it is a pointer, do the same, and also handle ptr->ptr casts
+ // here.
+ const TargetData &TD = getAnalysis<TargetData>();
+ unsigned SrcWidth = TD.getTypeSizeInBits(SV->getType());
+ unsigned DestWidth = TD.getTypeSizeInBits(AllocaType);
+ unsigned SrcStoreWidth = TD.getTypeStoreSizeInBits(SV->getType());
+ unsigned DestStoreWidth = TD.getTypeStoreSizeInBits(AllocaType);
+ if (SV->getType()->isFloatingPoint())
+ SV = new BitCastInst(SV, IntegerType::get(SrcWidth),
+ SV->getName(), SI);
+ else if (isa<PointerType>(SV->getType()))
+ SV = new PtrToIntInst(SV, TD.getIntPtrType(), SV->getName(), SI);
+
+ // Always zero extend the value if needed.
+ if (SV->getType() != AllocaType)
+ SV = new ZExtInst(SV, AllocaType, SV->getName(), SI);
+
+ // If this is a big-endian system and the store is narrower than the
+ // full alloca type, we need to do a shift to get the right bits.
+ int ShAmt = 0;
+ if (TD.isBigEndian()) {
+ // On big-endian machines, the lowest bit is stored at the bit offset
+ // from the pointer given by getTypeStoreSizeInBits. This matters for
+ // integers with a bitwidth that is not a multiple of 8.
+ ShAmt = DestStoreWidth - SrcStoreWidth - Offset;
+ } else {
+ ShAmt = Offset;
+ }
+
+ // Note: we support negative bitwidths (with shr) which are not defined.
+ // We do this to support (f.e.) stores off the end of a structure where
+ // only some bits in the structure are set.
+ APInt Mask(APInt::getLowBitsSet(DestWidth, SrcWidth));
+ if (ShAmt > 0 && (unsigned)ShAmt < DestWidth) {
+ SV = BinaryOperator::CreateShl(SV,
+ ConstantInt::get(SV->getType(), ShAmt),
+ SV->getName(), SI);
+ Mask <<= ShAmt;
+ } else if (ShAmt < 0 && (unsigned)-ShAmt < DestWidth) {
+ SV = BinaryOperator::CreateLShr(SV,
+ ConstantInt::get(SV->getType(),-ShAmt),
+ SV->getName(), SI);
+ Mask = Mask.lshr(ShAmt);
+ }
+
+ // Mask out the bits we are about to insert from the old value, and or
+ // in the new bits.
+ if (SrcWidth != DestWidth) {
+ assert(DestWidth > SrcWidth);
+ Old = BinaryOperator::CreateAnd(Old, ConstantInt::get(~Mask),
+ Old->getName()+".mask", SI);
+ SV = BinaryOperator::CreateOr(Old, SV, SV->getName()+".ins", SI);
+ }
+ }
+ return SV;
+}
+
+
/// PointsToConstantGlobal - Return true if V (possibly indirectly) points to
/// some part of a constant global variable. This intentionally only accepts
projects / oota-llvm.git / blobdiff