SC doesn't support non-compress stores yet, and tpu.vector_store has compressed semantics today.
Although Pallas doesn't expose masked store to non-compress uses today, it's not obvious that _store_lowering_rule supports only compressed semantics.
This CL makes this restriction clear.
Once we add support for non-compress stores, compress will be used to differentiate between tpu.vector_compress_store and tpu.vector_store.
google/jax