The role of ABC?

[ApeachM]

Hi, YosysHQ.
As you know, the licenses are different each other between yosys and abc.

But I noticed that yosys uses abc when I build the yosys project.
I want to know if I do know use abc. Will it not synthesis the logic?
Is abc for logic synthesis, or it is only for timing driven logic optimization and technology mapping?

Thank you, very much.

[nakengelhardt]

abc is used for technology mapping, and it also does some gate-level optimizations. You can synthesize to internal gate-level representation without abc by using synth -noabc, but it will be somewhat lower quality results. There are also some alternatives for lut mapping, but they are much lower quality: synth -lut -flowmap has decent results but tends to crash, synth -lut -noabc will use one lut per gate which is very inefficient.