Currently when LCRA spills it also fills on every single usage of the
spilled value. This leads to a lot of cases where a spill is immediately
followed by a fill.
This patch reduces fills by LCRA by simply not filling until reaching
either the index that caused LCRA to fail allocating registers, or the
end of a block.
Reviewed-by: Eric R. Smith <eric.smith@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37299>
ba293ebbc8