#243 Extraction chooses non-port label Issue created by d-m-bailey Using magic

8.3.398

When there are multiple labels on a net, magic sometimes chooses the non-port label which results in LVS port mismatch. The net* signals in

serv_1

port list are internal signals that are shorted to ports.

serv_1.v

assign io_oeb[0] = net566;
 assign io_oeb[1] = net567;
 assign io_oeb[2] = net568;
 assign io_oeb[3] = net569;
 assign io_oeb[4] = net570;
 assign io_out[2] = net571;
 assign io_out[3] = net572;
 assign io_out[4] = net573;

serv_1.ext

equiv "io_oeb[0]" "net566"
equiv "io_oeb[1]" "net567"
equiv "io_oeb[2]" "net568"
equiv "io_oeb[3]" "net569"
equiv "io_oeb[4]" "net570"

user_project_wrapper.gds.spice

.subckt serv_1 net568 io_in[3] net569 net567 net573 net571 net570 io_out[1] io_out[0]
+ io_in[0] io_in[4] io_in[1] io_in[2] net566 net572 vdd vss

This results in mismatched ports at th

serv_1

level

Circuit 1: serv_1                                                       |Circuit 2: serv_1
------------------------------------------------------------------------|------------------------------------------------------------------------
net571                                                                  |io_oeb[3] **Mismatch**

and after altering ports to match, at the top level

serv_1 u_serv_1 (.vdd(vdd),
...
    .io_oeb({_08_,
    _07_,
    _06_,
    io_oeb[18],
    io_oeb[17]}),

Top level pin list.

io_oeb[18]                                                              |(no matching pin)
io_oeb[17]                                                              |(no matching pin)

Explicitly flattening

serv_1

results in a match. Ports are expected to have precedence over internal node text. To reproduce,

export PDK=gf180mcuC
tar xzf test-gflvs.tgz
cd test-gflvs
./run_test

Not a minimal case, but only takes about 10 minutes.

lvs.noflatten.report

will contain the mismatched results without flattening.

lvs.flatten.report

will contain the matched results with flattening (the size errors are netgen issue). test-gflvs.tgz RTimothyEdwards/magic