In the Yosys manual I read
C.108 read
-sv2005 -sv2009 -sv2012
load HDL designs Load the specified Verilog/SystemVerilog files. (Full SystemVerilog support is only available via Verific.)
C.113 read_verilog – read modules from Verilog file
-sv enable support for SystemVerilog features. (only a small subset of SystemVerilog is supported)
Is there a concise spec anywhere about this? If not, a guidline? Which Verilog and which SystemVerilog?
What is Verific?
In Clifford: A Free and Open Source Verilog-to-Bitstream Flow for iCE40 FPGAs Wolf says that "Verilog is pretty much everything from Verilog 2005". What not from Verilog 2005? Changes over time from this late 2015 lecture?