Quartus 25.1.1 Pro Fitter Error with Agilex3

Hi,

To clarify, the workaround is to add a register with a "noprune" attribute that registers the unused bit of the ddrio ibuf to ensure it doesn't get optimized away :

   wire               ethphy_source_valid; // To CDC
   wire [1:0]         ethphy_rx_ctl; // From IO
   (* noprune *)
   reg                ethphy_rx_ctl0_reg;

   always @(posedge eth_rx_clk) ethphy_rx_ctl0_reg <= ethphy_rx_ctl[0];
   assign ethphy_source_valid = ethphy_rx_ctl[1];

Cheers,
Steffen