synth - generic synthesis script

    synth [options]

This command runs the default synthesis script. This command does not operate
on partly selected designs.

    -top <module>
        use the specified module as top module (default='top')

    -auto-top
        automatically determine the top of the design hierarchy

    -flatten
        flatten the design before synthesis. this will pass '-auto-top' to
        'hierarchy' if no top module is specified.

    -encfile <file>
        passed to 'fsm_recode' via 'fsm'

    -nofsm
        do not run FSM optimization

    -noabc
        do not run abc (as if yosys was compiled without ABC support)

    -noalumacc
        do not run 'alumacc' pass. i.e. keep arithmetic operators in
        their direct form ($add, $sub, etc.).

    -nordff
        passed to 'memory'. prohibits merging of FFs into memory read ports

    -run <from_label>[:<to_label>]
        only run the commands between the labels (see below). an empty
        from label is synonymous to 'begin', and empty to label is
        synonymous to the end of the command list.


The following commands are executed by this synthesis command:

    begin:
        hierarchy -check [-top <top> | -auto-top]

    coarse:
        proc
        flatten    (if -flatten)
        opt_expr
        opt_clean
        check
        opt
        wreduce
        alumacc
        share
        opt
        fsm
        opt -fast
        memory -nomap
        opt_clean

    fine:
        opt -fast -full
        memory_map
        opt -full
        techmap
        opt -fast
        abc -fast
        opt -fast

    check:
        hierarchy -check
        stat
        check