quartus 12.1 compilation too long using altiobuf in CycloneV

Thanks for your quick reply, Rysc.

if with just the IO bufs, i am afraid of that quartus will synthesis off relevant logic and at the same time it is not convenient for me to revise the project.

the fact should be pointed out is that, the compilation time depends a lot on how many altiobuf instances i use.

i have instantiated 48 altiobuf instances now, when i directly use input_pad -> ddio_in in all 48 channels, as i said above, compilation time is around 50 minutes;

however, when i use input_pad->ddio_in in 47 channels, and use input_pad->altiobuf(with programmable input delay enabled)->ddio_in in 48th channel, compilation time is around 90 minutes.

when i use input_pad->altiobuf(with programmable input delay enabled)->ddio_in in all 48 channels, compilation time is beyond 24 hours and still not successfully routed.

Regards,

ingdxdy