void RewriteLoadUserOfWholeAlloca(LoadInst *LI, AllocationInst *AI,
SmallVector<AllocaInst*, 32> &NewElts);
- const Type *CanConvertToScalar(Value *V, bool &IsNotTrivial);
+ bool CanConvertToScalar(Value *V, bool &IsNotTrivial, const Type *&ResTy,
+ uint64_t Offset);
void ConvertToScalar(AllocationInst *AI, const Type *Ty);
- void ConvertUsesToScalar(Value *Ptr, AllocaInst *NewAI, unsigned Offset);
+ void ConvertUsesToScalar(Value *Ptr, AllocaInst *NewAI, uint64_t Offset);
Value *ConvertUsesOfLoadToScalar(LoadInst *LI, AllocaInst *NewAI,
- unsigned Offset);
+ uint64_t Offset);
Value *ConvertUsesOfStoreToScalar(StoreInst *SI, AllocaInst *NewAI,
- unsigned Offset);
+ uint64_t Offset);
static Instruction *isOnlyCopiedFromConstantGlobal(AllocationInst *AI);
};
}
// If we can turn this aggregate value (potentially with casts) into a
// simple scalar value that can be mem2reg'd into a register value.
+ // IsNotTrivial tracks whether this is something that mem2reg could have
+ // promoted itself. If so, we don't want to transform it needlessly. Note
+ // that we can't just check based on the type: the alloca may be of an i32
+ // but that has pointer arithmetic to set byte 3 of it or something.
bool IsNotTrivial = false;
- if (const Type *ActualType = CanConvertToScalar(AI, IsNotTrivial))
- if (IsNotTrivial && ActualType != Type::VoidTy) {
+ const Type *ActualType = 0;
+ if (CanConvertToScalar(AI, IsNotTrivial, ActualType, 0))
+ if (IsNotTrivial && ActualType &&
+ TD->getTypeSizeInBits(ActualType) < SRThreshold*8) {
ConvertToScalar(AI, ActualType);
Changed = true;
continue;
}
}
-/// MergeInType - Add the 'In' type to the accumulated type so far. If the
-/// types are incompatible, return true, otherwise update Accum and return
-/// false.
+/// MergeInType - Add the 'In' type to the accumulated type (Accum) so far at
+/// the offset specified by Offset (which is specified in bytes).
///
-/// There are three cases we handle here:
-/// 1) An effectively-integer union, where the pieces are stored into as
-/// smaller integers (common with byte swap and other idioms).
-/// 2) A union of vector types of the same size and potentially its elements.
+/// There are two cases we handle here:
+/// 1) A union of vector types of the same size and potentially its elements.
/// Here we turn element accesses into insert/extract element operations.
-/// 3) A union of scalar types, such as int/float or int/pointer. Here we
-/// merge together into integers, allowing the xform to work with #1 as
-/// well.
-static bool MergeInType(const Type *In, const Type *&Accum,
+/// This promotes a <4 x float> with a store of float to the third element
+/// 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.
+static void MergeInType(const Type *In, uint64_t Offset, const Type *&Accum,
const TargetData &TD) {
// If this is our first type, just use it.
- const VectorType *PTy;
- if (Accum == Type::VoidTy || In == Accum) {
+ if (Accum == 0 || In == Type::VoidTy ||
+ // Or if this is a same type, keep it.
+ (In == Accum && Offset == 0)) {
Accum = In;
- } else if (In == Type::VoidTy) {
- // Noop.
- } else if (In->isInteger() && Accum->isInteger()) { // integer union.
- // Otherwise pick whichever type is larger.
- if (cast<IntegerType>(In)->getBitWidth() >
- cast<IntegerType>(Accum)->getBitWidth())
- Accum = In;
- } else if (isa<PointerType>(In) && isa<PointerType>(Accum)) {
- // Pointer unions just stay as one of the pointers.
- } else if (isa<VectorType>(In) || isa<VectorType>(Accum)) {
- if ((PTy = dyn_cast<VectorType>(Accum)) &&
- PTy->getElementType() == In) {
- // Accum is a vector, and we are accessing an element: ok.
- } else if ((PTy = dyn_cast<VectorType>(In)) &&
- PTy->getElementType() == Accum) {
- // In is a vector, and accum is an element: ok, remember In.
- Accum = In;
- } else if ((PTy = dyn_cast<VectorType>(In)) && isa<VectorType>(Accum) &&
- PTy->getBitWidth() == cast<VectorType>(Accum)->getBitWidth()) {
- // Two vectors of the same size: keep Accum.
- } else {
- // Cannot insert an short into a <4 x int> or handle
- // <2 x int> -> <4 x int>
- return true;
- }
- } else {
- // Pointer/FP/Integer unions merge together as integers.
- switch (Accum->getTypeID()) {
- case Type::PointerTyID: Accum = TD.getIntPtrType(); break;
- case Type::FloatTyID: Accum = Type::Int32Ty; break;
- case Type::DoubleTyID: Accum = Type::Int64Ty; break;
- case Type::X86_FP80TyID: return true;
- case Type::FP128TyID: return true;
- case Type::PPC_FP128TyID: return true;
- default:
- assert(Accum->isInteger() && "Unknown FP type!");
- break;
- }
-
- switch (In->getTypeID()) {
- case Type::PointerTyID: In = TD.getIntPtrType(); break;
- case Type::FloatTyID: In = Type::Int32Ty; break;
- case Type::DoubleTyID: In = Type::Int64Ty; break;
- case Type::X86_FP80TyID: return true;
- case Type::FP128TyID: return true;
- case Type::PPC_FP128TyID: return true;
- default:
- assert(In->isInteger() && "Unknown FP type!");
- break;
- }
- return MergeInType(In, Accum, TD);
+ return;
+ }
+
+ if (const VectorType *VATy = dyn_cast<VectorType>(Accum)) {
+ if (VATy->getElementType() == In &&
+ Offset % TD.getTypePaddedSize(In) == 0 &&
+ Offset < TD.getTypePaddedSize(VATy))
+ return; // Accum is a vector, and we are accessing an element: ok.
+ if (const VectorType *VInTy = dyn_cast<VectorType>(In))
+ if (VInTy->getBitWidth() == VATy->getBitWidth() && Offset == 0)
+ return; // Two vectors of the same size: keep either one of them.
}
- return false;
-}
-/// getIntAtLeastAsBigAs - Return an integer type that is at least as big as the
-/// specified type. If there is no suitable type, this returns null.
-const Type *getIntAtLeastAsBigAs(unsigned NumBits) {
- if (NumBits > 64) return 0;
- if (NumBits > 32) return Type::Int64Ty;
- if (NumBits > 16) return Type::Int32Ty;
- if (NumBits > 8) return Type::Int16Ty;
- return Type::Int8Ty;
+ if (const VectorType *VInTy = dyn_cast<VectorType>(In)) {
+ // In is a vector, and we are accessing an element: keep V.
+ if (VInTy->getElementType() == Accum &&
+ Offset % TD.getTypePaddedSize(Accum) == 0 &&
+ Offset < TD.getTypePaddedSize(VInTy)) {
+ Accum = VInTy;
+ return;
+ }
+ }
+
+ // Otherwise, we have a case that we can't handle with an optimized form.
+ // Convert the alloca to an integer that is as large as the largest store size
+ // of the value values.
+ uint64_t InSize = TD.getTypeStoreSizeInBits(In)+8*Offset;
+ uint64_t ASize = TD.getTypeStoreSizeInBits(Accum);
+ if (InSize > ASize) ASize = InSize;
+ Accum = IntegerType::get(ASize);
}
-/// CanConvertToScalar - V is a pointer. If we can convert the pointee to a
-/// single scalar integer type, return that type. Further, if the use is not
-/// a completely trivial use that mem2reg could promote, set IsNotTrivial. If
-/// there are no uses of this pointer, return Type::VoidTy to differentiate from
-/// failure.
+/// CanConvertToScalar - V is a pointer. If we can convert the pointee and all
+/// its accesses to use a to single scalar type, return true, and set ResTy to
+/// the new type. Further, if the use is not a completely trivial use that
+/// mem2reg could promote, set IsNotTrivial. Offset is the current offset from
+/// the base of the alloca being analyzed.
///
-const Type *SROA::CanConvertToScalar(Value *V, bool &IsNotTrivial) {
- const Type *UsedType = Type::VoidTy; // No uses, no forced type.
- const PointerType *PTy = cast<PointerType>(V->getType());
-
+bool SROA::CanConvertToScalar(Value *V, bool &IsNotTrivial,
+ const Type *&ResTy, uint64_t Offset) {
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI!=E; ++UI) {
Instruction *User = cast<Instruction>(*UI);
if (LoadInst *LI = dyn_cast<LoadInst>(User)) {
+ // Don't break volatile loads.
if (LI->isVolatile())
- return 0;
-
- // 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;
+ return false;
+ MergeInType(LI->getType(), Offset, ResTy, *TD);
continue;
}
if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
// Storing the pointer, not into the value?
if (SI->getOperand(0) == V || SI->isVolatile()) 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!
-
- if (MergeInType(SI->getOperand(0)->getType(), UsedType, *TD))
- return 0;
+ MergeInType(SI->getOperand(0)->getType(), Offset, ResTy, *TD);
continue;
}
- if (BitCastInst *CI = dyn_cast<BitCastInst>(User)) {
+
+ if (BitCastInst *BCI = dyn_cast<BitCastInst>(User)) {
+ if (!CanConvertToScalar(BCI, IsNotTrivial, ResTy, Offset))
+ return false;
IsNotTrivial = true;
- const Type *SubTy = CanConvertToScalar(CI, IsNotTrivial);
- if (!SubTy || MergeInType(SubTy, UsedType, *TD)) return 0;
continue;
}
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(User)) {
- // Check to see if this is stepping over an element: GEP Ptr, int C
- if (GEP->getNumOperands() == 2 && isa<ConstantInt>(GEP->getOperand(1))) {
- unsigned Idx = cast<ConstantInt>(GEP->getOperand(1))->getZExtValue();
- unsigned ElSize = TD->getTypePaddedSize(PTy->getElementType());
- unsigned BitOffset = Idx*ElSize*8;
- if (BitOffset > 64 || !isPowerOf2_32(ElSize)) return 0;
-
- IsNotTrivial = true;
- const Type *SubElt = CanConvertToScalar(GEP, IsNotTrivial);
- if (SubElt == 0) return 0;
- if (SubElt != Type::VoidTy && SubElt->isInteger()) {
- const Type *NewTy =
- getIntAtLeastAsBigAs(TD->getTypePaddedSizeInBits(SubElt)+BitOffset);
- if (NewTy == 0 || MergeInType(NewTy, UsedType, *TD)) return 0;
- continue;
- }
- // Cannot handle this!
- return 0;
- }
+ // If this is a GEP with a variable indices, we can't handle it.
+ if (!GEP->hasAllConstantIndices())
+ return false;
- if (GEP->getNumOperands() == 3 &&
- isa<ConstantInt>(GEP->getOperand(1)) &&
- isa<ConstantInt>(GEP->getOperand(2)) &&
- cast<ConstantInt>(GEP->getOperand(1))->isZero()) {
- // We are stepping into an element, e.g. a structure or an array:
- // GEP Ptr, i32 0, i32 Cst
- const Type *AggTy = PTy->getElementType();
- unsigned Idx = cast<ConstantInt>(GEP->getOperand(2))->getZExtValue();
-
- if (const ArrayType *ATy = dyn_cast<ArrayType>(AggTy)) {
- if (Idx >= ATy->getNumElements()) return 0; // Out of range.
- } else if (const VectorType *VectorTy = dyn_cast<VectorType>(AggTy)) {
- // Getting an element of the vector.
- if (Idx >= VectorTy->getNumElements()) return 0; // Out of range.
-
- // Merge in the vector type.
- if (MergeInType(VectorTy, UsedType, *TD)) return 0;
-
- const Type *SubTy = CanConvertToScalar(GEP, IsNotTrivial);
- if (SubTy == 0) return 0;
-
- if (SubTy != Type::VoidTy && MergeInType(SubTy, UsedType, *TD))
- return 0;
-
- // We'll need to change this to an insert/extract element operation.
- IsNotTrivial = true;
- continue; // Everything looks ok
-
- } else if (isa<StructType>(AggTy)) {
- // Structs are always ok.
- } else {
- return 0;
- }
- const Type *NTy =
- getIntAtLeastAsBigAs(TD->getTypePaddedSizeInBits(AggTy));
- if (NTy == 0 || MergeInType(NTy, UsedType, *TD)) return 0;
- const Type *SubTy = CanConvertToScalar(GEP, IsNotTrivial);
- if (SubTy == 0) return 0;
- if (SubTy != Type::VoidTy && MergeInType(SubTy, UsedType, *TD))
- return 0;
- continue; // Everything looks ok
- }
- return 0;
+ // Compute the offset that this GEP adds to the pointer.
+ SmallVector<Value*, 8> Indices(GEP->op_begin()+1, GEP->op_end());
+ uint64_t GEPOffset = TD->getIndexedOffset(GEP->getOperand(0)->getType(),
+ &Indices[0], Indices.size());
+ // See if all uses can be converted.
+ if (!CanConvertToScalar(GEP, IsNotTrivial, ResTy, Offset+GEPOffset))
+ return false;
+ IsNotTrivial = true;
+ continue;
}
- // Cannot handle this!
- return 0;
+ // Otherwise, we cannot handle this!
+ return false;
}
- return UsedType;
+ return true;
}
/// ConvertToScalar - The specified alloca passes the CanConvertToScalar
/// predicate and is non-trivial. Convert it to something that can be trivially
/// promoted into a register by mem2reg.
void SROA::ConvertToScalar(AllocationInst *AI, const Type *ActualTy) {
- DOUT << "CONVERT TO SCALAR: " << *AI << " TYPE = "
- << *ActualTy << "\n";
+ DOUT << "CONVERT TO SCALAR: " << *AI << " TYPE = " << *ActualTy << "\n";
++NumConverted;
- BasicBlock *EntryBlock = AI->getParent();
- assert(EntryBlock == &EntryBlock->getParent()->getEntryBlock() &&
- "Not in the entry block!");
- EntryBlock->getInstList().remove(AI); // Take the alloca out of the program.
-
// Create and insert the alloca.
AllocaInst *NewAI = new AllocaInst(ActualTy, 0, AI->getName(),
- EntryBlock->begin());
+ AI->getParent()->begin());
ConvertUsesToScalar(AI, NewAI, 0);
- delete AI;
+ AI->eraseFromParent();
}
///
/// 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) {
+void SROA::ConvertUsesToScalar(Value *Ptr, AllocaInst *NewAI, uint64_t Offset) {
while (!Ptr->use_empty()) {
Instruction *User = cast<Instruction>(Ptr->use_back());
if (LoadInst *LI = dyn_cast<LoadInst>(User)) {
- Value *NV = ConvertUsesOfLoadToScalar(LI, NewAI, Offset);
- LI->replaceAllUsesWith(NV);
+ LI->replaceAllUsesWith(ConvertUsesOfLoadToScalar(LI, NewAI, Offset));
LI->eraseFromParent();
continue;
}
if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
assert(SI->getOperand(0) != Ptr && "Consistency error!");
-
- Value *SV = ConvertUsesOfStoreToScalar(SI, NewAI, Offset);
- new StoreInst(SV, NewAI, SI);
+ new StoreInst(ConvertUsesOfStoreToScalar(SI, NewAI, Offset), NewAI, SI);
SI->eraseFromParent();
continue;
}
}
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(User)) {
- const PointerType *AggPtrTy =
- cast<PointerType>(GEP->getOperand(0)->getType());
- unsigned AggSizeInBits =
- TD->getTypePaddedSizeInBits(AggPtrTy->getElementType());
-
- // Check to see if this is stepping over an element: GEP Ptr, int C
- unsigned NewOffset = Offset;
- if (GEP->getNumOperands() == 2) {
- unsigned Idx = cast<ConstantInt>(GEP->getOperand(1))->getZExtValue();
- unsigned BitOffset = Idx*AggSizeInBits;
-
- NewOffset += BitOffset;
- ConvertUsesToScalar(GEP, NewAI, NewOffset);
- GEP->eraseFromParent();
- continue;
- }
-
- assert(GEP->getNumOperands() == 3 && "Unsupported operation");
-
- // We know that operand #2 is zero.
- unsigned Idx = cast<ConstantInt>(GEP->getOperand(2))->getZExtValue();
- const Type *AggTy = AggPtrTy->getElementType();
- if (const SequentialType *SeqTy = dyn_cast<SequentialType>(AggTy)) {
- unsigned ElSizeBits =
- TD->getTypePaddedSizeInBits(SeqTy->getElementType());
-
- NewOffset += ElSizeBits*Idx;
- } else {
- const StructType *STy = cast<StructType>(AggTy);
- unsigned EltBitOffset =
- TD->getStructLayout(STy)->getElementOffsetInBits(Idx);
-
- NewOffset += EltBitOffset;
- }
- ConvertUsesToScalar(GEP, NewAI, NewOffset);
+ // Compute the offset that this GEP adds to the pointer.
+ SmallVector<Value*, 8> Indices(GEP->op_begin()+1, GEP->op_end());
+ uint64_t GEPOffset = TD->getIndexedOffset(GEP->getOperand(0)->getType(),
+ &Indices[0], Indices.size());
+ ConvertUsesToScalar(GEP, NewAI, Offset+GEPOffset*8);
GEP->eraseFromParent();
continue;
}
-
assert(0 && "Unsupported operation!");
abort();
}
/// 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
+/// Offset is an offset from the original alloca, in bytes 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) {
+ uint64_t 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.
+ // If the load is of the whole new alloca, no conversion is needed.
+ if (NV->getType() == LI->getType() && Offset == 0)
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 the result alloca is a vector type, this is either an element
+ // access or a bitcast to another vector type of the same size.
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);
if (Offset) {
unsigned EltSize = TD->getTypePaddedSizeInBits(VTy->getElementType());
Elt = Offset/EltSize;
- Offset -= EltSize*Elt;
+ assert(EltSize*Elt == Offset && "Invalid modulus in validity checking");
}
- 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;
+ // Return the element extracted out of it.
+ return new ExtractElementInst(NV, ConstantInt::get(Type::Int32Ty, Elt),
+ "tmp", LI);
}
+ // Otherwise, this must be a union that was converted to an integer value.
const IntegerType *NTy = cast<IntegerType>(NV->getType());
// If this is a big-endian system and the load is narrower than the
// 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),
+ 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),
+ NV = BinaryOperator::CreateShl(NV,
+ ConstantInt::get(NV->getType(), -ShAmt),
LI->getName(), LI);
// Finally, unconditionally truncate the integer to the right width.
// 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()) {
+ } else if (LI->getType()->isFloatingPoint() ||
+ isa<VectorType>(LI->getType())) {
// Just do a bitcast, we know the sizes match up.
NV = new BitCastInst(NV, LI->getType(), LI->getName(), LI);
} else {
/// 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) {
+ uint64_t 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)) {
+ return SV;
+ }
+
+ if (const VectorType *VTy = 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
SV = new BitCastInst(SV, AllocaType, SV->getName(), SI);
} else {
// Must be an element insertion.
- unsigned Elt = Offset/TD->getTypePaddedSizeInBits(PTy->getElementType());
+ unsigned Elt = Offset/TD->getTypePaddedSizeInBits(VTy->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);
+ return SV;
+ }
+
+
+ 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() || isa<VectorType>(SV->getType()))
+ 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 {
- 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);
- }
+ 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;
}