Significant area reduction using abc during canonicalize

[lo7ev]

Adding synth -flatten; abc into the synth_canonicalize.tcl after hierarchy check and before writing actual rtlil leads to 35% reduction of area after the floorplaning stage on various designs. Is this a mistake or a feature?

[KrystalDelusion]

What is synth_canonicalize

[lo7ev]

https://github.com/The-OpenROAD-Project/OpenROAD-flow-scripts/blob/master/flow/scripts/synth_canonicalize.tcl

This one. I saw that this script is called before synth.tcl in flow/scripts when running make synth. And it writes rtlil file.

I run ORFS with

make clean 
make synth
make floorplan
make synth-report

[KrystalDelusion]

Right. But this is Yosys, not ORFS?

[lo7ev]

Sorry, I might be stupid. I thought i was writing to ORFS discussion. Thanks for you time

[KrystalDelusion]

No worries :) We do sometimes get discussions/issues referred from them when it is about Yosys specifics that they don't have an answer for

[lo7ev]

Wrong place to ask