[Bug bootstrap/79814] pass-instances.def:36:14: error: ‘*<unknown>.gcc::pass_manager::pass_warn_unused_result_1’ is used uninitialized in this function

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79814

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
>Well, the C++ frontend inserts CLOBBERs at the beginning of constructors so either this zeroing is pointless (and likely optimized out) or the frontend produces wrong-code in doing so.

It is pointless.  See PR 71885 for the reasons why.