instrument: fix instrumentation if driver is a pin driving a single instrumented bit

bin/FIJI/Netlist.pm

@@ -554,8 +554,16 @@ sub instrument_net {
                 if ($netname->{'netname'} eq $net->name) {
                     $netname->{'netname'} = $net_name_tmp; # FIXME: do we need to force a re-link (by deleting $connection->nets)?
                     # This net is a vector if the underlying net is a bus and we do not just select a single bit
+                    # If driver is a vector we need a vectored intermediate bus.
+                    # This is the case if
+                    #   - the underlying net is a vector and there are no indices
+                    #   - the underlying net is a vector and there are two different indices
                     if (defined($net->msb) && (!defined($netname->{'msb'}) || $netname->{'msb'} != $netname->{'lsb'})) {
                         $driver_is_vector = 1;
+                    } else {
+                        # Make sure we do not output the index unnecessarily (if the driver is a single bit of a vector)
+                        undef($netname->{'msb'});
+                        undef($netname->{'lsb'});
                     }
                 }
             }