[Bug tree-optimization/116651] vector::operator== on a newly created single element vector is not that good

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116651

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #4)
> From bug 109442 comment #36
> 
> > I believe strlen_pass::handle_builtin_memcmp should eventually move to 
> > forwprop
> (fold_stmt may not inspect immediate uses).  That would help this particular
> case.
> 
> yes I agree. There was a few other related `== 0` optimizations I want to
> add. e.g. strlen is one of them.

that movement fixes comment #3 . I will go ahead and test and submit the patch
for that.

For comment #0, I filed PR 121710 for part of the missed optimization there; I
think the loop part is what I filed as PR 121711 but I am not 100% sure.