Instead of using the -divide_by option, you can
use the -edges option to directly describe the waveform of the
generated clock based on the edges of the master clock. The argument is a list of
master clock edge indexes used for defining the position in time of the generated
clock edges, starting with the rising clock edge.
The following example is equivalent to the generated clock defined in Example One: Simple Division by 2.
# waveform specified with -edges instead of -divide_by
create_generated_clock -name clkdiv2 -source [get_pins REGA/C] -edges {1 3 5} \ [get_pins REGA/Q]