[Bug middle-end/124651] ICE with -Winfinite-recursion due to recursive rather than work queue/list

[heiko at hexco dot de via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124651

--- Comment #12 from Heiko Eißfeldt <heiko at hexco dot de> ---
My minimal replacement so far. m_visited might be replaced by BB's visited
later