https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53808
--- Comment #12 from Rafael Avila de Espindola <rafael.espindola at gmail dot com> --- Note that this bug is present once more when -fno-use-all-virtuals is used. With the original testcase gcc again produces an undefined reference to _ZN3barD0Ev. Is -fno-use-all-virtuals intended to be an abi breaking option? If so it would be nice to document that.
