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yuri91 merged 1 commit into from
Mar 24, 2025
Merged

SIMDLowering: Remove uses of GPET #289

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145 changes: 34 additions & 111 deletions llvm/lib/CheerpUtils/SIMDLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -101,12 +101,23 @@ struct SIMDLoweringVisitor: public InstVisitor<SIMDLoweringVisitor, VectorParts>
const FixedVectorType* vecType = cast<FixedVectorType>(I.getType());
Type* elType = vecType->getElementType();
const unsigned num = vecType->getNumElements();
VectorParts p = visitValue(I.getOperand(0));
assert(p.values[0]->getType() == elType->getPointerTo() &&
p.values.size() == num);
VectorParts p = visitValue(I.getPointerOperand());
IRBuilder<> Builder(&I);

// If the operand hasn't been lowered, we have to do a bitcast and some geps.
if (p.values.size() == 0)
{
Value* bitcast = Builder.CreateBitCast(I.getPointerOperand(), elType->getPointerTo());
p.values.push_back(bitcast);
for (unsigned i = 1; i < num; i++)
{
Value* index[] = {ConstantInt::get(Int32Ty, i)};
Value* gep = Builder.CreateInBoundsGEP(elType, bitcast, index);
p.values.push_back(gep);
}
}

VectorParts result;
IRBuilder<> Builder(&I);
for (unsigned i = 0; i < num; i++)
{
Value* load = Builder.CreateLoad(elType, p.values[i]);
Expand All @@ -123,12 +134,26 @@ struct SIMDLoweringVisitor: public InstVisitor<SIMDLoweringVisitor, VectorParts>
return VectorParts();

const FixedVectorType* vecType = cast<FixedVectorType>(I.getValueOperand()->getType());
Type* elType = vecType->getElementType();
const unsigned num = vecType->getNumElements();
VectorParts v = visitValue(I.getValueOperand());
VectorParts p = visitValue(I.getPointerOperand());
IRBuilder<> Builder(&I);

// If the pointer operand was not lowered, we have to do a bitcast and some geps.
if (p.values.size() == 0)
{
Value* bitcast = Builder.CreateBitCast(I.getPointerOperand(), elType->getPointerTo());
p.values.push_back(bitcast);
for (unsigned i = 1; i < num; i++)
{
Value* index[] = {ConstantInt::get(Int32Ty, i)};
Value* gep = Builder.CreateInBoundsGEP(elType, bitcast, index);
p.values.push_back(gep);
}
}

VectorParts result;
IRBuilder<> Builder(&I);
for (unsigned i = 0; i < num; i++)
{
Value* store = Builder.CreateStore(v.values[i], p.values[i]);
Expand All @@ -141,34 +166,6 @@ struct SIMDLoweringVisitor: public InstVisitor<SIMDLoweringVisitor, VectorParts>

VectorParts visitBitCastInst(BitCastInst& I)
{
if (I.getDestTy()->isPointerTy())
{
const Type* pointedType = I.getDestTy()->getPointerElementType();
if (!shouldLower(pointedType))
return VectorParts();

// If we're casting to a pointer to a vector, instead create
// pointers to the separate elements.
const FixedVectorType* vecType = cast<FixedVectorType>(pointedType);
const unsigned num = vecType->getNumElements();
Type* elType = vecType->getElementType()->getPointerTo();
IRBuilder<> Builder(&I);
VectorParts result;
Value* firstValue = I.getOperand(0);
if (elType != firstValue->getType())
firstValue = Builder.CreateBitCast(firstValue, elType);
result.values.push_back(firstValue);

for (unsigned i = 1; i < num; i++)
{
Value* index[] = {ConstantInt::get(Int32Ty, i)};
Value* gep = Builder.CreateInBoundsGEP(vecType->getElementType(), firstValue, index);
result.values.push_back(gep);
}
toDelete.push_back(&I);
changed = true;
return result;
}
if (!shouldLower(I.getDestTy()) && !shouldLower(I.getSrcTy()))
return VectorParts();

Expand Down Expand Up @@ -379,10 +376,10 @@ struct SIMDLoweringVisitor: public InstVisitor<SIMDLoweringVisitor, VectorParts>

VectorParts visitAllocaInst(AllocaInst& I)
{
if (!shouldLower(I.getType()->getPointerElementType()))
if (!shouldLower(I.getAllocatedType()))
return VectorParts();

const FixedVectorType* vecType = cast<FixedVectorType>(I.getType()->getPointerElementType());
const FixedVectorType* vecType = cast<FixedVectorType>(I.getAllocatedType());
Type* newType = vecType->getElementType();
unsigned amount = vecType->getNumElements();
IRBuilder<> Builder(&I);
Expand Down Expand Up @@ -532,70 +529,11 @@ struct SIMDLoweringVisitor: public InstVisitor<SIMDLoweringVisitor, VectorParts>
return result;
}

Type* recursiveCreateType(Type* originalType)
{
Type* newType = originalType;
if (const FixedVectorType* vecType = dyn_cast<FixedVectorType>(originalType))
newType = ArrayType::get(vecType->getElementType(), vecType->getNumElements());
else if (const ArrayType* arrayType = dyn_cast<ArrayType>(originalType))
{
Type* subType = recursiveCreateType(arrayType->getElementType());
newType = ArrayType::get(subType, arrayType->getNumElements());
}
else if (const StructType* structType = dyn_cast<StructType>(originalType))
{
SmallVector<Type*, 4> subTypes;
for (unsigned i = 0; i < structType->getNumElements(); i++)
subTypes.push_back(recursiveCreateType(structType->getElementType(i)));
newType = StructType::get(context, subTypes);
}
return newType;
};

VectorParts visitGetElementPtrInst(GetElementPtrInst& I)
{
if (!I.getType()->isVectorTy() && !(I.getType()->isPointerTy() && I.getType()->getPointerElementType()->isVectorTy()))
if (!I.getType()->isVectorTy())
return VectorParts();

if (I.getType()->isPointerTy())
{
const FixedVectorType* vecType = cast<FixedVectorType>(I.getType()->getPointerElementType());
if (!lowerAll && cheerp::getVectorBitwidth(vecType) <= 128)
return VectorParts();

// This is a pointer to a vector. We lower this to several GEPs to the first element.
const unsigned num = vecType->getNumElements();
Type* elementType = vecType->getElementType();
Type* arrayType = ArrayType::get(elementType, num);

// Has the pointed operand been lowered?
VectorParts v = visitValue(I.getPointerOperand());
Value* pointerOp = I.getPointerOperand();
Value* bitcastBase = pointerOp;
if (v.values.size() > 0)
bitcastBase = v.values[0];

// Create a bitcast to a new type that has an array instead of a vector for the innermost part.
IRBuilder<> Builder(&I);
Type* newType = recursiveCreateType(pointerOp->getType()->getPointerElementType());
Value* bitcast = Builder.CreateBitCast(bitcastBase, newType->getPointerTo());
// Create a new GEP using the same indices as before.
SmallVector<Value*, 4> indices;
for (auto it = I.idx_begin(); it != I.idx_end(); it++)
indices.push_back(*it);
Value* gep = Builder.CreateInBoundsGEP(newType, bitcast, indices);

// Now we create GEPs into this latest GEP to get the elements.
VectorParts result;
for (unsigned i = 0; i < num; i++)
{
SmallVector<Value*, 4> index = { ConstantInt::get(Int32Ty, 0), ConstantInt::get(Int32Ty, i) };
result.values.push_back(Builder.CreateInBoundsGEP(arrayType, gep, index));
}
toDelete.push_back(&I);
changed = true;
return result;
}
const FixedVectorType* vecType = cast<FixedVectorType>(I.getType());
const unsigned num = vecType->getNumElements();
IRBuilder<> Builder(I.getNextNode());
Expand Down Expand Up @@ -1026,8 +964,7 @@ struct SIMDLoweringVisitor: public InstVisitor<SIMDLoweringVisitor, VectorParts>
if (it != cache.end())
return it->second;

if (!shouldLower(V->getType()) &&
!(V->getType()->isPointerTy() && shouldLower(V->getType()->getPointerElementType())))
if (!shouldLower(V->getType()))
return VectorParts();

VectorParts ret;
Expand Down Expand Up @@ -1064,20 +1001,6 @@ struct SIMDLoweringVisitor: public InstVisitor<SIMDLoweringVisitor, VectorParts>
for (unsigned i = 0; i < amount; i++)
ret.values.push_back(uvElement);
}
else if (ConstantExpr* ce = dyn_cast<ConstantExpr>(V))
{
const FixedVectorType* vecType = cast<FixedVectorType>(ce->getType()->getPointerElementType());
const unsigned num = vecType->getNumElements();
Type* elementType = vecType->getElementType()->getPointerTo();
Constant* bitcast = ConstantExpr::getBitCast(ce, elementType);
ret.values.push_back(bitcast);
for (unsigned i = 1; i < num; i++)
{
Value* index[] = {ConstantInt::get(Int32Ty, i)};
Value* gep = ConstantExpr::getGetElementPtr(vecType->getElementType(), bitcast, index);
ret.values.push_back(gep);
}
}
else
{
llvm::errs() << *V << "\n";
Expand Down
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