These are required for ray-tracing. There are many cases where the
ray-tracing hardware may decide to execute some but not all of our
shaders. In these cases, it needs a shader to execute at the end which
will pop the stack back to the shader which called traceRay().
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7356>
Jason Ekstrand
72354b0e9d