[Bug tree-optimization/55001] Handle VEC_COND_EXPR better in tree-vect-generic.c

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55001

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
Note it's going to be _way_ easier to tackle when we got rid of vcond{,u,eq}
since then the compares and the condition can be lowered separately.