[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 #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
>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.