In the previous thread I suggested using a wrapper cblas_cgemv_wrapper that effectively "reverts" the API to what it was prior to ACCELERATE_NEW_LAPACK=1 and ACCELERATE_LAPACK_ILP64=1. It's a bit pain to introduce such a wrapper (or a few if you need it for more than one function), but overall this seems the least painful solution. Note that the wrapper implementation doesn't need to use a pyramid of doom as it taking advantage of automatic "array to unsafe pointer function parameter" conversion done by Swift.