On Mon, Jul 14 2025, Jonathan Wakely via Gcc wrote: > On Mon, 14 Jul 2025 at 14:57, Thomas de Bock via Gcc <gcc@gcc.gnu.org> wrote: >> >> Hello all, I've been looking into a compiler optimization implemented by >> clang but not gcc that substitutes a __dynamic_cast call for a simple vtable >> ptr comparison in the case that the class being cast to is final. >> >> However this brings issues with it in some cases (specified in thread). I >> believe having the optimization disabled by default, but adding a compiler >> flag to enable it would be ideal. Code for the optimization is mostly done >> so I'm looking to have this optimization available in gcc somehow now, >> interested in hearing any opinions on this :) >> >> thread link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63164#add_comment > > I agree that we don't want to perform the optimization by default, but > it would be useful to have an option to enable it when you know it's > safe to do so.
If it materializes in this form, could we include it in -Ofast? Thanks, Martin
