radv will lower this intrinsic before gets to llvm, so we just need to implement it in radeonsi. The tes version will be used in tess lower too. Reviewed-by: Marek Olšák <marek.olsak@amd.com> Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com> Signed-off-by: Qiang Yu <yuq825@gmail.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16705>