[Bug tree-optimization/112325] Missed vectorization of reduction after unrolling

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112325

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Yes, as I said in comment#2.  Note I specifically ended up not open-coding the
reduction because of concerns of efficiency.  So a target should only provide
reduc_*_scal patterns when they are more efficient than open-coding with
the obvious sequence.

That possibly means fixing the issue I mentioned in comment#2 will not be
enough to get this BB vectorized on x86.