Assertion on a stack of ICESTOR_LCs

[BigET]

Version:

nextpnr-ice40 -- Next Generation Place and Route (git sha1 2898d81)

Verilog input:

top.zip

line to execute:

yosys -p 'synth_ice40 -top top -json top.json' top.v

nextpnr-ice40 --lp8k --package cm81 --pcf pins.pcf --asc top.asc --json top.json