COMBINATIONAL  LOOP  NOTE


If you synthesize your design and you have loops in your synthesis tool delay report, you should redesign.

Loops in the delay report indicate the existence of combinational feedback loops in your design.

Combinational loops can produce oscillatory behavior and are generally not desired in a reliable digital design. 

Use of the synthesis tool option to break combinational loops statically during timing analysis is not permitted.

A combinational loop example