What happens to a pmapped computation with uncommitted data?

[bycn]

Hi,
I read through https://jax.readthedocs.io/en/latest/faq.html#controlling-data-and-computation-placement-on-devices but I don't think it covers this case:
Let's say we had matrix A that's device_put_replicated across the 8 local devices to form rA. Then, we pmap across rA with a function that computes the product of A * x, where x is an uncommitted array. Where are the computations done and where does x end up after computation?