add comment explaining the check

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DrMeepster 2022-02-16 16:52:06 -08:00 committed by GitHub
parent ae32f43c50
commit d0b508e1a7
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@ -330,6 +330,8 @@ impl<'tcx> LayoutLlvmExt<'tcx> for TyAndLayout<'tcx> {
ty::Ref(..) | ty::RawPtr(_) => {
return self.field(cx, index).llvm_type(cx);
}
// only wide pointer boxes are handled as pointers
// thin pointer boxes with scalar allocators are handled by the general logic below
ty::Adt(def, substs) if def.is_box() && cx.layout_of(substs.type_at(1)).is_zst() => {
let ptr_ty = cx.tcx.mk_mut_ptr(self.ty.boxed_ty());
return cx.layout_of(ptr_ty).scalar_pair_element_llvm_type(cx, index, immediate);