The definitions are not clear
-asynch Traverse through asynch edges
-clock Traverse through clock edges
-synch Traverse through synch edges
So for example I created this test case:
I get the fanins of the "In_pin" input using "-async" , "-sync" and "-clock" option and I get no difference between the 3 results.
So how can I see the difference between these options in a design?
What u can do is use the tecnology map viewer to look into the netlist.
-asynch Traverse through asynch edges, this normal happened on after LUT1 where no clock involve.
-synch Traverse through synch edges, usually, on the register where clock is involve.
-clock Traverse through clock edges, on the clock path rather than the data path. for example, output of PLL.