https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83069
--- Comment #14 from Jan Hubicka <hubicka at gcc dot gnu.org> --- Letting entry block frequency to drop to 0 has bad effect on IPA profile propagation. Since new profile count arithmetics is overflow safe, I think we should just cap it to max_count in such case. The loop as written will never finish anyway so and if the bounds are not known we should teach branch prediction to work out that it is not a good idea to estimate very deep loop nests with "large" trip count. I will prepare patch that silence the assert. Honza
