The algorithms were originally implemented by Marek Olšák,
hence the copyright to AMD.
This commit just ports the LLVM based implementation to NIR,
using the new intrinsics added earlier.
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10525>
