Yosys dfflibmap now maps flip flops with enable - demo

[widlarizer]

This PR demonstrates functionality added in YosysHQ/yosys#4698. We expect a QoR improvement on sky130hd and sky130hs and no change on other PDKs

[maliberty]

I'm confused - you are updating the yosys submodule which points to our fork but somehow getting upstream changes? I'm confused as to what is happening to make that possible.

[widlarizer]

I suspect that this is an effect of fork networks: "Commits to any repository in a network can be accessed from any repository in the same network, including the upstream repository, even after a fork is deleted." - About permissions and visibility of forks

[povik]

This can be closed now that Yosys has been updated to 0.48 in #2620 and enable type flip-flop inference happens by default.