/// Given an LLVM IR aggregate type and a sequence of insertvalue or
/// extractvalue indices that identify a member, return the linearized index of
/// the start of the member, i.e the number of element in memory before the
/// Given an LLVM IR aggregate type and a sequence of insertvalue or
/// extractvalue indices that identify a member, return the linearized index of
/// the start of the member, i.e the number of element in memory before the