[Bug ipa/108740] two identical functions but the code generated differs. Why?

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108740

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Piotr from comment #3)
> (In reply to Richard Biener from comment #2)
> > Hmm, ICF + re-inlining makes it ignore some of the pointless volatile dance?
> 
> why the code is different abstracting form the sense of the assignment?

It is the volatileness of the argument. which by the way for C++20 is
deprecated ...