https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100940
--- Comment #8 from Patrick Palka <ppalka at gcc dot gnu.org> --- (In reply to TC from comment #7) > (In reply to Patrick Palka from comment #6) > > > > For the other adaptors, we still unconditionally disable perfect forwarding > > call wrapper semantics. I'm not sure if the performance/diagnostic tradeoff > > is worth it to enable perfect forwarding semantics when the function object > > is non-trivial. > > Personally, I'd happily pay some diagnostic complexity when I get things > wrong if that means I get better performance when I get things right. Good > diagnostics only matter when my code is broken, while performance matters > when my code is working. The former should (hopefully) be a transient > condition. Sounds good; a followup patch that implements this is at https://gcc.gnu.org/pipermail/gcc-patches/2021-June/572829.html The patch limits the "simple" forwarding case to only trivially copyable extra arguments, and does so for all adaptors. So take_while/drop_while/filter/transform(std::function) as well as split(non_triv_copyable_view) would be considered non-simple under this restriction.
