[Bug tree-optimization/126027] `if (t == CST) t = CST; ` is should be handled by SCCVN

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126027

--- Comment #1 from Drea Pinski <pinskia at gcc dot gnu.org> ---
> I assume we are not using the predicates in visit_reference_op_store but only
> expressions_equal_p.

Not just in visit_reference_op_store but also
eliminate_dom_walker::eliminate_stmt .