ID:19712 Duplication of registers and lcell_comb due to max-fanout constraints caused the netlist to double in size. Synthesis will not process all constraints.

CAUSE: The duplication of registers and lcell_combs due to MAX_FANOUT constraints and maxfan attributes has caused the netlist to double in size. This is likely caused by an excessive number of MAX_FANOUT contraints or maxfan attributes. This can happen if a low MAX_FANOUT is set on a large portion of the design.

ACTION: Review MAX_FANOUT constraints and maxfan attributes to ensure there will not be too many duplications.