[Bug libstdc++/98677] std::regex constructor triggers valgrind under clang++ with undefined sanitizer; possible use-after-move

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98677

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Yes, I used both ubsan and valgrind, and couldn't reproduce it with any version
of GCC or clang I tried, including with the headers from GCC 10.2

I might try to reproduce it on Ubuntu, but if it's specific to Ubuntu then it
should be reported to them, not here. Upstream GCC doesn't reproduce the
problem.