Added simple $dlatch support to opt_rmdff

diff --git a/passes/opt/opt_rmdff.cc b/passes/opt/opt_rmdff.cc
index 2939c48478b4fd3da6cda6679bbf157b2e2eaabe..84af6482343e76286d5f1a55c6e44d6831ae886e 100644 (file)
--- a/passes/opt/opt_rmdff.cc
+++ b/passes/opt/opt_rmdff.cc
@@ -29,6 +29,33 @@ PRIVATE_NAMESPACE_BEGIN
 SigMap assign_map, dff_init_map;
 SigSet<RTLIL::Cell*> mux_drivers;
 
+bool handle_dlatch(RTLIL::Module *mod, RTLIL::Cell *dlatch)
+{
+       SigSpec sig_e = dlatch->getPort("\\EN");
+
+       if (sig_e == State::S0)
+       {
+               RTLIL::Const val_init;
+               for (auto bit : dff_init_map(dlatch->getPort("\\Q")))
+                       val_init.bits.push_back(bit.wire == NULL ? bit.data : State::Sx);
+               mod->connect(dlatch->getPort("\\Q"), val_init);
+               goto delete_dlatch;
+       }
+
+       if (sig_e == State::S1)
+       {
+               mod->connect(dlatch->getPort("\\Q"), dlatch->getPort("\\D"));
+               goto delete_dlatch;
+       }
+
+       return false;
+
+delete_dlatch:
+       log("Removing %s (%s) from module %s.\n", dlatch->name.c_str(), dlatch->type.c_str(), mod->name.c_str());
+       mod->remove(dlatch);
+       return true;
+}
+
 bool handle_dff(RTLIL::Module *mod, RTLIL::Cell *dff)
 {
        RTLIL::SigSpec sig_d, sig_q, sig_c, sig_r;
@@ -178,6 +205,7 @@ struct OptRmdffPass : public Pass {
                        mux_drivers.clear();
 
                        std::vector<RTLIL::IdString> dff_list;
+                       std::vector<RTLIL::IdString> dlatch_list;
                        for (auto &it : mod_it.second->cells_) {
                                if (it.second->type == "$mux" || it.second->type == "$pmux") {
                                        if (it.second->getPort("\\A").size() == it.second->getPort("\\B").size())
@@ -198,6 +226,7 @@ struct OptRmdffPass : public Pass {
                                if (it.second->type == "$_DFF_PP1_") dff_list.push_back(it.first);
                                if (it.second->type == "$dff") dff_list.push_back(it.first);
                                if (it.second->type == "$adff") dff_list.push_back(it.first);
+                               if (it.second->type == "$dlatch") dlatch_list.push_back(it.first);
                        }
 
                        for (auto &id : dff_list) {
@@ -205,6 +234,12 @@ struct OptRmdffPass : public Pass {
                                                handle_dff(mod_it.second, mod_it.second->cells_[id]))
                                        total_count++;
                        }
+
+                       for (auto &id : dlatch_list) {
+                               if (mod_it.second->cells_.count(id) > 0 &&
+                                               handle_dlatch(mod_it.second, mod_it.second->cells_[id]))
+                                       total_count++;
+                       }
                }
 
                assign_map.clear();