Vectorize an inner loop that depends on the outer loop

[abdouskamel]

Hello,

Actually that's not an issue but a question concerning Tiramisu. I don't know if it's the right place for asking questions, thus I'm sorry if it's inconvenient.

I want to implement a computation that looks like this with tiramisu :

for (i = 0; i < N; ++i)
    for (j = 0; j < i; ++j)
        S0
    S1

I have done it following the tutorials, but now I want to apply vectorization to the loop j with vector length v. The problem is that, as stated in the documentation :

the vectorization of a loop that has less than v iterations is not correct.

Thus, for the first iterations where i < v, the vectorization will be incorrect because the loop j iterates for less than v iterations. I think that this can be fixed by splitting the outer loop like that :

for (i = 0; i < v; ++i)
    for (j = 0; j < i; ++j)
        S0
    S1

for (i = v; i < N; ++i)
    for (j = 0; j < i; ++j)
        S0
    S1

and apply vectorization only to the second loop. This can be done easily in the declaration of the algorithm (layer 1), but I think that I must resolve this issue in layer 2 because it's an issue related to the optimization of the algorithm.

I searched in the documentation but didn't find a way to do that, so I am asking for your help.

Thank you.