From what I can tell, the recent work on SampleBias/SampleLevel did all of the work for us, we just need to take the same framework and include the case for the `sample_l` instruction.
Tested with some shaders from the native Linux version of Little Racers STREET.
-- v5: vkd3d-shader/tpf: For sample_l/sample_b, set lod swizzle to SCALAR.