[Bug sanitizer/78294] -fsanitize=thread broken

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78294

--- Comment #8 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
I've opened https://sourceware.org/bugzilla/show_bug.cgi?id=20805.
It would be good if someone could come up with a small testcase.