Add explanatory comment about inefficient wire removal and remove superfluous call...

Co-Authored-By: Eddie Hung <eddie@fpgeh.com>

diff --git a/frontends/ast/ast.cc b/frontends/ast/ast.cc
index 46801d6914ccca8884e2e2219eef433b289839dc..24d6f56d88fc607783094a1667cc5993d1a6e621 100644 (file)
--- a/frontends/ast/ast.cc
+++ b/frontends/ast/ast.cc
@@ -1458,20 +1458,24 @@ RTLIL::IdString AstModule::derive(RTLIL::Design *design, dict<RTLIL::IdString, R
                // Now that the interfaces have been exploded, we can delete the dummy port related to every interface.
                for(auto &intf : interfaces) {
                        if(mod->wire(intf.first) != nullptr) {
+                               // Normally, removing wires would be batched together as it's an
+                               //   expensive operation, however, in this case doing so would mean
+                               //   that a cell with the same name cannot be created (below)...
+                               // Since we won't expect many interfaces to exist in a module,
+                               //   we can let this slide...
                                pool<RTLIL::Wire*> to_remove;
                                to_remove.insert(mod->wire(intf.first));
                                mod->remove(to_remove);
                                mod->fixup_ports();
-                               // We copy the cell of the interface to the sub-module such that it can further be found if it is propagated
-                               // down to sub-sub-modules etc.
-                               RTLIL::Cell * new_subcell = mod->addCell(intf.first, intf.second->name);
+                               // We copy the cell of the interface to the sub-module such that it
+                               //   can further be found if it is propagated down to sub-sub-modules etc.
+                               RTLIL::Cell *new_subcell = mod->addCell(intf.first, intf.second->name);
                                new_subcell->set_bool_attribute("\\is_interface");
                        }
                        else {
                                log_error("No port with matching name found (%s) in %s. Stopping\n", log_id(intf.first), modname.c_str());
                        }
                }
-               mod->fixup_ports();
 
                // If any interfaces were replaced, set the attribute 'interfaces_replaced_in_module':
                if (interfaces.size() > 0) {