How to suppress 'warning: Timing checks are not supported.' warnings?

[zapta]

When we run the command below, we get tens fo 'Timing checks are not supported.' warnings. Is there a flag or a similar way to suppress them, without modifying the source file or running post processing filters?

iverilog -g2012 -o _build/blinky_tb.out -DVCD_OUTPUT=_build/blinky_tb -I"/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin" "/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v" blinky.v blinky_tb.v

/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:176: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:190: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:191: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:207: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:208: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:226: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:227: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:228: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:246: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:247: warning: Timing checks are not supported.
...

The first warning is about the $setup() function below

(* abc9_flop, lib_whitebox *)
module DFF (output reg Q, input CLK, D);
        parameter [0:0] INIT = 1'b0;
        initial Q = INIT;

        specify
                (posedge CLK => (Q : D)) = (480, 660);
                $setup(D, posedge CLK, 576);
        endspecify
                
        always @(posedge CLK)
                Q <= D;
endmodule

[martinwhitaker]

There isn't, but IMO these should be suppressed when -gno-specify (the default) is used.

[zapta]

@martinwhitaker, do you mean adding -gno-specify to the command? We still get the warnings:

iverilog -g2012 -gno-specify -o _build/default/blinky_tb.out -DVCD_OUTPUT=_build/default/blinky_tb -DAPIO_SIM=0 -I"/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin" "/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v" blinky.v blinky_tb.v
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:176: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:190: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:191: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:207: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:208: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:226: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:227: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:228: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:246: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:247: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:265: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:266: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:267: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:286: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:305: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:306: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:325: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:344: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:345: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:363: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:377: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:378: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:394: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:395: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:413: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:414: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:415: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:433: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:434: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:452: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:453: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:454: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:473: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:492: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:493: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:512: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:531: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:532: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1029: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1030: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1031: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1065: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1066: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1067: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1106: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1107: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1108: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1151: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1152: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1153: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1188: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1189: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1190: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1230: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1231: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1232: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1522: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1523: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1524: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1525: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1526: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1527: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1528: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1529: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1530: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1531: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1532: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1533: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1623: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1624: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1625: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1626: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1627: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1628: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1629: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1630: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1631: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1632: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1633: warning: Timing checks are not supported.
/Users/user/.apio/packages/oss-cad-suite/share/yosys/gowin/cells_sim.v:1634: warning: Timing checks are not supported.
vvp _build/default/blinky_tb.out -dumpfile=_build/default/blinky_tb.vcd
VCD info: dumpfile _build/default/blinky_tb.vcd opened for output.
End of simulation
blinky_tb.v:33: $finish called at 6100 (1ns)

[martinwhitaker]

No, I meant that at present -gno-specify does not suppress these warnings, but I think the compiler should be modified so that it does.

[zapta]

Should I find a feature request for it?

[martinwhitaker]

I've just created an issue from this discussion.