pakesson_ has quit [Read error: Connection reset by peer]
Asu has quit [Remote host closed the connection]
Asu has joined ##openfpga
<ZirconiumX>
Does anybody here actually use synth_ice40/synth_ecp5 -dff? Did they even know it existed? I suspect a few do (Yosys devs plus relatively advanced users), but it seems to me like a lot of the people who use Yosys are unaware of its existence
Asuu has joined ##openfpga
Asu has quit [Ping timeout: 256 seconds]
<awygle>
What does it do?
<ZirconiumX>
...Correction, -retime
<ZirconiumX>
I keep calling it -dff because that's what it passes to abc
Asuu has quit [Remote host closed the connection]
<adamgreig>
i've used retime but only when i am desperate to shave a ns or two off timing
<adamgreig>
it hasn't usually made a huge difference? but i'm probably using it wrong
<adamgreig>
i have a vague understanding of what it should do but haven't understood it enough to really make it make a difference, I guess
<adamgreig>
there's loads of tempting arguments for synth_ice40 which i usually play with to see what does well, but mostly it makes less difference than a different nextpnr seed...