[Bug tree-optimization/123113] factor_out_conditional_operation could be improved to handle `EDGE_COUNT (merge->preds) != 2`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123113

--- Comment #11 from Drea Pinski <pinskia at gcc dot gnu.org> ---
All patches submitted.

cs-lim-limted for phiopt:
https://gcc.gnu.org/pipermail/gcc-patches/2026-April/713112.html
https://gcc.gnu.org/pipermail/gcc-patches/2026-April/713113.html

cs-elim:
https://gcc.gnu.org/pipermail/gcc-patches/2026-April/713237.html

factor of phiopt:
https://gcc.gnu.org/pipermail/gcc-patches/2026-April/713265.html

The first set is only needed to fix PR 124006. But the second one is needed
(with an extra one) is needed to get better code generation out of it for
non-riscv.