It depends on how integrated your SIMD strategy is into the overall technical design. Tail handling is much easier if you can afford SIMD-friendly padding so a full vector load/store is possible even if you have to manually mask. That avoids a lot of the hassle of breaking down memory accesses just to avoid a page fault or setting off the memory checker.

Beyond that -- unit testing. I don't see enough of it for vectorized routines. SIMD widths are small enough that you can usually just test all possible offsets right up against a guard page and brute force verify that no overruns occur.