Otherwise ctx->VertexProgram._VaryingInputs might not be up to date.
We can't do this in update_program because this breaks vbo_save_playback_vertex_list_gallium:
const GLbitfield enabled = node->enabled_attribs[mode];
_mesa_set_varying_vp_inputs(ctx, enabled); <-- update _VaryingInputs
if (ctx->NewState)
_mesa_update_state(ctx); <-- calls update_program, reverting the
change made above
Fixes: c97961a855 ("mesa: fix 38% decrease in display list performance of Viewperf2020/NX8_StudioAA")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/9441
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25956>