[Bug c/99693] -O2 not move 'if' checks on const data outside the loops

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99693

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Loop unswitching is correctly only turned on at -O3+. So you want to move it to
-O2. Note loop unswitching can cause performance problems due to increase of
usage of the icache and such.