[Bug middle-end/115832] Very slow compilation with `-fsanitize=undefined -O2` and std::sort

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115832

--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #3)
> I looked at the output of -ftime-report, there does not seen anything that
> sticks out really. Plus with -fsanitize=undefined just means there will
> almost definitely be much more basic blocks and many more registers alive.

And _GLIBCXX_DEBUG means there is A LOT more work being done on every step of
the algorithm.