Get size of memory access with non-primitive type

Hi all,

I am trying to get the size of memory access (load) using dyn_cast<LoadInst>(Inst)->getType()->getPrimitiveSizeinBit(), which works for most cases. However, for load instructions like "%18 = load i8*, i8** %11, align 8, !tbaa !10" where we have double star (**) pointer access, such method would only return a value of 0. I am wondering is there any method that could allow me to get the size of loading in this case?

Thanks in advance,

Tom