[Bug tree-optimization/77689] Missing vectorization lead to huge performance loss

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77689

--- Comment #20 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #19)
> for the original testcase in comment #0, renaming main to f and changing the
> return type to void, the trunk of GCC can optimize the function to just a
> return now.
> 
> Note the renaming is because of inlining heurstics and the call to reserve
> is not being inlined.
> 
> So we can close this as fixed.

I should say with -Ofast . Though `-O3 -fno-math-errno` is enough for that too.