Non-trivial collects (i.e., ones that will introduce moves because the
sources don't line-up with the destination) may cause source intervals
to get implicitly moved when they are inserted as children of the
destination interval. Since we don't support moving intervals in shared
RA, this may cause illegal register allocations. Prevent this by
creating a new top-level interval for the destination so that the source
intervals will be left alone.
Signed-off-by: Job Noorman <jnoorman@igalia.com>
Fixes: fa22b0901a ("ir3/ra: Add specialized shared register RA/spilling")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31978>
b36a7ce0f1