In Non-Project Mode, you can iterate between various optimization commands with different options. For example, you can run phys_opt_design -directive AggressiveFanoutOpt followed by phys_opt_design -directive AlternateFlowWithRetiming to run different physical synthesis optimizations on a placed design that does not meet timing.
Running phys_opt_design iteratively can provide
timing improvement. The phys_opt_design command attempts
to optimize the top timing problem paths. By running phys_opt_design iteratively, more critical paths can benefit from the
optimization. Running phys_opt_design at the post-route
stage reroutes any nets that might have been unrouted. Therefore, after running phys_opt_design at post-route, you do not need to
explicitly run route_design.