[Bug tree-optimization/44794] pre- and post-loops should not be unrolled.

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44794

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Heuristic to not unroll loops with prefetches is missing.  The aprefetch pass
could set ->unroll to 1 in the loop structure.