Why is my set_clock_groups command ignored during static timing analysis?

Due to a problem in the Quartus® II software versions 11.1 SP2 and earlier, the set_clock_groups command may be ignored with no warning or error message if you use incorrect syntax by including a command that returns a group or collection within braces {}.

In the following example, the set_clock_groups command is ignored:

set_clock_groups -asynchronous -group {[get_clocks {clkA}]} -group {clkC}

To avoid this behavior, use the correct syntax as shown below:

• Remove the braces {} from around the command that returns a collection:

  set_clock_groups -asynchronous -group [get_clocks {clkA}] -group {clkC}

• Replace the get_clocks command with a list:

  set_clock_groups -asynchronous -group {clkA} -group {clkC}