Study of the vectorization efficiency of loop nests with an irregular number of iterations

Computation vectorization is an important low-level optimization used to create highly efficient parallel code. However, when used in context with an unknown program execution profile, a danger of low effectiveness of the application emerges. This is especially pronounced when vectorizing nests of cycles with an irregular number of iterations of the inner loop. The article discusses a comparison of the theoretical and practical efficiency of vectorization on the example of Shell sorting, since this program code is extremely inconvenient for vectorization.