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

[rguenth at gcc dot gnu.org]

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

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2026-06-29
     Ever confirmed|0                           |1
                 CC|                            |rguenth at gcc dot gnu.org
             Status|UNCONFIRMED                 |NEW

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
You'd need to query for the equality of the RHS and the value of the LHS in
eliminate_dom_walker::eliminate_stmt in addition to operand_equal_p.
Via vn_nary_op_lookup_pieces and then looking up a predicated value
via vn_nary_op_get_predicated_value.