Switch to potentially-sparse net users array

This uses a new data structure for net.users that allows gaps, so
removing a port from a net is no longer an O(n) operation on the number
of users the net has.

Signed-off-by: gatecat <gatecat@ds0.me>

1 files changed, 1 insertions, 1 deletions

diff --git a/ice40/bitstream.cc b/ice40/bitstream.cc
index 89f84262..48fbc132 100644
--- a/ice40/bitstream.cc
+++ b/ice40/bitstream.cc
@@ -1146,7 +1146,7 @@ bool read_asc(Context *ctx, std::istream &in)
                             if (port.second.type == PORT_OUT)
                                 net->driver = ref;
                             else
-                                net->users.push_back(ref);
+                                port.second.user_idx = net->users.add(ref);
                         }
                     }
                 }