Value *PropagateJuliaAddrspaces::LiftPointer(Value *V, Type *LocTy, Instruction *InsertPt) {
SmallVector<Value *, 4> Stack;
Value *CurrentV = V;
// Follow pointer casts back, see if we're based on a pointer in
// an untracked address space, in which case we're allowed to drop
// intermediate addrspace casts.
while (true) {
Stack.push_back(CurrentV);
if (isa<BitCastInst>(CurrentV))
CurrentV = cast<BitCastInst>(CurrentV)->getOperand(0);
else if (isa<AddrSpaceCastInst>(CurrentV)) {
CurrentV = cast<AddrSpaceCastInst>(CurrentV)->getOperand(0);
if (!isSpecialAS(getValueAddrSpace(CurrentV)))
break;
}
else if (isa<GetElementPtrInst>(CurrentV)) {
if (LiftingMap.count(CurrentV)) {
CurrentV = LiftingMap[CurrentV];
break;
} else if (Visited.count(CurrentV)) {
return nullptr;
}
Visited.insert(CurrentV);
CurrentV = cast<GetElementPtrInst>(CurrentV)->getOperand(0);
} else
break;
}
if (!CurrentV->getType()->isPointerTy())
return nullptr;
if (isSpecialAS(getValueAddrSpace(CurrentV)))
return nullptr;
// Ok, we're allowed to change the address space of this load, go back and
// reconstitute any GEPs in the new address space.
for (Value *V : llvm::reverse(Stack)) {
GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V);
if (!GEP)
continue;
if (LiftingMap.count(GEP)) {
CurrentV = LiftingMap[GEP];
continue;
}
GetElementPtrInst *NewGEP = cast<GetElementPtrInst>(GEP->clone());
ToInsert.push_back(std::make_pair(NewGEP, GEP));
Type *GEPTy = GEP->getSourceElementType();
Type *NewRetTy = cast<PointerType>(GEP->getType())->getElementType()->getPointerTo(getValueAddrSpace(CurrentV));
NewGEP->mutateType(NewRetTy);
if (cast<PointerType>(CurrentV->getType())->getElementType() != GEPTy) {
auto *BCI = new BitCastInst(CurrentV, GEPTy->getPointerTo());
ToInsert.push_back(std::make_pair(BCI, NewGEP));
CurrentV = BCI;
}
NewGEP->setOperand(GetElementPtrInst::getPointerOperandIndex(), CurrentV);
LiftingMap[GEP] = NewGEP;
CurrentV = NewGEP;
}
if (LocTy && cast<PointerType>(CurrentV->getType())->getElementType() != LocTy) {
auto *BCI = new BitCastInst(CurrentV, LocTy->getPointerTo());
ToInsert.push_back(std::make_pair(BCI, InsertPt));
CurrentV = BCI;
}
return CurrentV;
}
