188.8.131.52. Localized Clock Enable
The localized clock enable has a small fan-out. The localized clock enable often occurs in a clocked process or an always block. In these cases, the signal’s behavior is undefined under a particular branch of a conditional case or if statement. As a result, the signal retains its previous value, which is a clock enable.
To check whether a design has clock enables, view the Fitter Report > Plan Stage > Control Signals Compilation report and check the Usage column. Because the localized clock enable has a small fan-out, retiming is easy and usually does not cause any timing issues.