Inadvertently, because of a sequence of changes elsewhere, this pass
ended up not having any effect:
- Before Gfx5 the optimization is not applicable.
- On Gfx5-6 it doesn't apply because it sampler operations don't
currently use LOAD_PAYLOAD, but write the MOVs directly. Not clear to
me whether they ever did.
- On Gfx7+ it doesn't apply anymore because now the logical sampler
operations are now lowered directly to SENDs, and the is_tex() check
would skip them.
Since the LOAD_PAYLOAD implementation applies for Gfx7+ only, rework the
pass to work again by handling SEND instructions. To make the pass
easier, the optimization will happen before opt_split_sends() so only
one LOAD_PAYLOAD needs to be cared for.
Update the code to accept BAD_FILE sources in addition to zeros, these
are added in some cases as padding and effectively are don't care
values, so we can assume them zeros.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25742>
Caio Oliveira
daeab51a62