Author Name: David Chinnery
Original Redmine Issue: 343 from https://www.veripool.org
Original Date: 2011-05-04
Original Assignee: Wilson Snyder (@wsnyder)

Hi Wilson,

I just sent an email to you about this, bug figured I'd also submit it here.
Not sure if this should be submitted as an issue or a patch, so I've submitted it as an issue.

When a pin is deleted, the net counts are not decremented. Hence if another driver is connected, there will be a lint error for multiple drivers.
Here is a fix for this issue. Add to Netlist/Net.pm:

sub used_in_dec {
return if (! $[0]->used_in());
$[0]->used_in(-1+$[0]->_used_in());
}
sub used_out_dec {
return if (! $[0]->used_out());
$[0]->used_out(-1+$[0]->_used_out());
}
sub used_inout_dec {
return if (! $[0]->used_inout());
$[0]->used_inout(-1+$[0]->_used_inout());
}

Update delete() in Netlist/Pin.pm as follows:

sub delete {
my $self = shift;

 if ($self->net && $self->port) {
$self->net->_used_in_dec()    if ($self->port->direction() eq 'in');
$self->net->_used_out_dec()   if ($self->port->direction() eq 'out');
$self->net->_used_inout_dec() if ($self->port->direction() eq 'inout');
 }
 my $h = $self->cell->_pins;
 delete $h->{$self->name};
 return undef;

}

Thanks,
Dave.

On 02/03/11 17:18, David Chinnery wrote:

[..]
I have run into an invalid lint warning after deleting an output pin,
then adding it back connected to the same net as it was connected to
before. I've attached a simple test case that exercises the issue.

A possible work around is to not delete a pin and then add the
connection, if the connection is to the same net as it was connected to
previously. However, this may not be viable when swapping a cell, say
from bfx1 to bfx2.
[..]
PS: Here's the invalid warning:

Reading Verilog file test.v ...
Linting before reconnecting net ...
Linting after reconnecting net ...
%Warning: test.v:2: Signal has multiple drivers (2): net1
Net:net1
Pin: cell1.A in
Pin: cell2.QB out