[Bug tree-optimization/98813] loop is sub-optimized if index is unsigned int with offset

[guojiufu at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98813

--- Comment #1 from Jiu Fu Guo <guojiufu at gcc dot gnu.org> ---
Since there are additional costs for the run-time check, we can see the benefit
if upbound `m` is large; if upbound is small (e.g. < 12), the vectorized code
(from clang) is worse than un-vectorized binary.