When we put NIR in the compiler stack for r300, indirect addressing broke
for gallium nine. DX's array indirects round the float value, so the DX
shader gets mapped to a TGSI "ARR ADDR[0] src.x" instruction. Translating
that to NIR maps to r0[f2i32(fround(src.x))]. While we might hope that in
translation back using nir-to-tgsi after optimization we would recognize
the construct and emit ARR again, that's going to be error prone (think
"what if src.x is in a NIR register?") so we need a fallback plan. r300
will be able to handle this lowering, so get it in place first to fix the
regression.
Fixes: #6297
Fixes: 7d2ea9b0ed ("r300: Request NIR shaders from mesa/st and use NIR-to-TGSI.")
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15870>
(cherry picked from commit 6947016b46)
4deeb4b55c