[Bug c++/79572] [6/7 Regression] Segfault with -O1 and higher on null reference

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79572

--- Comment #4 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
BTW clang diagnoses the issue with -fsanitize=undefined, but gcc doesn't:

  runtime error: reference binding to null pointer of type 'const int'