nir/lower_goto_ifs: Always include level dom_frontiers in prev_frontier

When we come in from some other level or from the parent, we need to
ensure that the reach set is in prev_frontier but we also need to
consider the dominance frontier of our level.  Otherwise, we may end up
leaving out possible blocks when computing the reach of a level.

Acked-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6750>
1 file changed