Improvements in opt_clean

Signed-off-by: Clifford Wolf <clifford@clifford.at>

diff --git a/passes/opt/opt_clean.cc b/passes/opt/opt_clean.cc
index 6ca6ac820f0c89faa0d3603eaf5ce89d4ea8dc73..bf802016985471ddb95eb752c430dc6214cef93f 100644 (file)
--- a/passes/opt/opt_clean.cc
+++ b/passes/opt/opt_clean.cc
@@ -232,7 +232,7 @@ bool check_public_name(RTLIL::IdString id)
        return true;
 }
 
-void rmunused_module_signals(RTLIL::Module *module, bool purge_mode, bool verbose)
+bool rmunused_module_signals(RTLIL::Module *module, bool purge_mode, bool verbose)
 {
        SigPool register_signals;
        SigPool connected_signals;
@@ -272,20 +272,17 @@ void rmunused_module_signals(RTLIL::Module *module, bool purge_mode, bool verbos
                }
        }
 
-       SigPool raw_used_signals_noaliases;
-       for (auto &it : module->connections_)
-               raw_used_signals_noaliases.add(it.second);
-
        module->connections_.clear();
 
        SigPool used_signals;
+       SigPool raw_used_signals;
        SigPool used_signals_nodrivers;
        for (auto &it : module->cells_) {
                RTLIL::Cell *cell = it.second;
                for (auto &it2 : cell->connections_) {
                        assign_map.apply(it2.second);
+                       raw_used_signals.add(it2.second);
                        used_signals.add(it2.second);
-                       raw_used_signals_noaliases.add(it2.second);
                        if (!ct_all.cell_output(cell->type, it2.first))
                                used_signals_nodrivers.add(it2.second);
                }
@@ -294,6 +291,7 @@ void rmunused_module_signals(RTLIL::Module *module, bool purge_mode, bool verbos
                RTLIL::Wire *wire = it.second;
                if (wire->port_id > 0) {
                        RTLIL::SigSpec sig = RTLIL::SigSpec(wire);
+                       raw_used_signals.add(sig);
                        assign_map.apply(sig);
                        used_signals.add(sig);
                        if (!wire->port_input)
@@ -330,11 +328,11 @@ void rmunused_module_signals(RTLIL::Module *module, bool purge_mode, bool verbos
                if (!purge_mode && check_public_name(wire->name)) {
                        // do not get rid of public names unless in purge mode
                } else
-               if (!raw_used_signals_noaliases.check_any(s1)) {
+               if (!raw_used_signals.check_any(s1)) {
                        // delete wires that aren't used by anything directly
                        goto delete_this_wire;
                } else
-               if (!used_signals_nodrivers.check_any(s2)) {
+               if (!used_signals.check_any(s2)) {
                        // delete wires that aren't used by anything indirectly, even though other wires may alias it
                        goto delete_this_wire;
                }
@@ -400,6 +398,8 @@ void rmunused_module_signals(RTLIL::Module *module, bool purge_mode, bool verbos
 
        if (verbose && del_temp_wires_count)
                log_debug("  removed %d unused temporary wires.\n", del_temp_wires_count);
+
+       return !del_wires_queue.empty();
 }
 
 bool rmunused_module_init(RTLIL::Module *module, bool purge_mode, bool verbose)
@@ -497,10 +497,10 @@ void rmunused_module(RTLIL::Module *module, bool purge_mode, bool verbose, bool
                module->design->scratchpad_set_bool("opt.did_something", true);
 
        rmunused_module_cells(module, verbose);
-       rmunused_module_signals(module, purge_mode, verbose);
+       while (rmunused_module_signals(module, purge_mode, verbose)) { }
 
        if (rminit && rmunused_module_init(module, purge_mode, verbose))
-               rmunused_module_signals(module, purge_mode, verbose);
+               while (rmunused_module_signals(module, purge_mode, verbose)) { }
 }
 
 struct OptCleanPass : public Pass {