[Bug middle-end/107905] 2x slowdown versus CLANG and ICL

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107905

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Alexander Monakov from comment #3)
> LLVM does a better job at code layout, and massively wins on the amount of
> executed branches (in particular unconditional jumps). With
> -fdisable-rtl-bbro gcc achieves a similar performance.

-freorder-blocks-algorithm=simple seems to improve it there too.
This does sound like all accidential really.
Throwing some [[unlikely]] around seems to get "better" layout.
I am I suspecting it all depends on the inputs and might not actually be a
performance difference if the inputs are better "weighted" ....