[Bug c/67764] -Wconversion generates false warnings for bitmask+cast expressions

[egall at gwmail dot gwu.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67764

--- Comment #3 from Eric Gallager <egall at gwmail dot gwu.edu> ---
Wait actually I think this might be a dup of bug 40752