Force LiberoSOC to particular FCCC?
In case anyone wants to know the answer, you use set_location macro_name -fixed yes x y, where macro_name is the name of the macro in the netlist and x and y are the x- and y-coordinates given around page 42 for the particular chip you are using. 

Note for the macro name, it works out to be something like &lt;instance_name&gt;/CCC_INST for FCCCs (In my case, it was instantiated as FCCC_0, so the netlist name was 'FCCC_0/CCC_INST').