Stores are vectorized with maximum vectorization factor of 16. Patch
tries to improve the situation and use maximal vectorization factor.
Someone more familiar with SLP should have a look at the diffs, but we need to address the compile-time question.
The artificial limit is only there to guard against excessive compile-time cost, so do you have data to show that difference? Or does this patch solve the (potential) problem in another way?
More discussion here: