ct_reg.setup_internals_mem();
                ct_reg.setup_stdcells_mem();
 
-               for (auto mod : design->modules()) {
-                       if (!design->selected_whole_module(mod->name)) {
-                               if (design->selected(mod))
-                                       log("Skipping module %s as it is only partially selected.\n", id2cstr(mod->name));
+               for (auto module : design->selected_whole_modules_warn()) {
+                       if (module->has_processes_warn())
                                continue;
-                       }
-                       if (!mod->processes.empty()) {
-                               log("Skipping module %s as it contains processes.\n", mod->name.c_str());
-                       } else {
-                               rmunused_module(mod, purge_mode, true);
-                       }
+                       rmunused_module(module, purge_mode, true);
                }
 
                ct.clear();
                count_rm_cells = 0;
                count_rm_wires = 0;
 
-               for (auto mod : design->modules()) {
-                       if (design->selected_whole_module(mod->name) && mod->processes.empty())
-                               do {
-                                       design->scratchpad_unset("opt.did_something");
-                                       rmunused_module(mod, purge_mode, false);
-                               } while (design->scratchpad_get_bool("opt.did_something"));
+               for (auto mod : design->selected_whole_modules()) {
+                       if (mod->has_processes())
+                               continue;
+                       do {
+                               design->scratchpad_unset("opt.did_something");
+                               rmunused_module(mod, purge_mode, false);
+                       } while (design->scratchpad_get_bool("opt.did_something"));
                }
 
                if (count_rm_cells > 0 || count_rm_wires > 0)
 
                }
                extra_args(args, argidx, design);
 
-               for (auto module : design->modules())
+               for (auto module : design->selected_modules())
                {
                        if (undriven)
                                replace_undriven(design, module);
 
                extra_args(args, 1, design);
 
                int total_count = 0;
-               for (auto mod : design->modules()) {
-                       if (!design->selected_whole_module(mod)) {
-                               if (design->selected(mod))
-                                       log("Skipping module %s as it is only partially selected.\n", log_id(mod));
+               for (auto module : design->selected_whole_modules_warn()) {
+                       if (module->has_processes_warn())
                                continue;
-                       }
-                       if (mod->has_processes_warn())
-                               continue;
-                       OptMuxtreeWorker worker(design, mod);
+                       OptMuxtreeWorker worker(design, module);
                        total_count += worker.removed_count;
                }
                if (total_count)
 
                extra_args(args, argidx, design);
 
                int total_count = 0;
-               for (auto &mod_it : design->modules_) {
-                       if (!design->selected(mod_it.second))
-                               continue;
-                       do {
-                               OptReduceWorker worker(design, mod_it.second, do_fine);
+               for (auto module : design->selected_modules())
+                       while (1) {
+                               OptReduceWorker worker(design, module, do_fine);
                                total_count += worker.total_count;
                                if (worker.total_count == 0)
                                        break;
-                       } while (1);
-               }
+                       }
 
                if (total_count)
                        design->scratchpad_set_bool("opt.did_something", true);
 
                extra_args(args, argidx, design);
 
                int total_count = 0;
-               for (auto &mod_it : design->modules_) {
-                       if (!design->selected(mod_it.second))
-                               continue;
-                       OptShareWorker worker(design, mod_it.second, mode_nomux);
+               for (auto module : design->selected_modules()) {
+                       OptShareWorker worker(design, module, mode_nomux);
                        total_count += worker.total_count;
                }