Improved opt_share for commutative standard cells

diff --git a/passes/opt/opt_share.cc b/passes/opt/opt_share.cc
index 9f79d0603b8bd714f46b0a31b057926a87464f34..6dd4daa0b389b3900e6ea06dcb27ef881ab52aa9 100644 (file)
--- a/passes/opt/opt_share.cc
+++ b/passes/opt/opt_share.cc
@@ -65,7 +65,20 @@ struct OptShareWorker
                for (auto &it : cell->parameters)
                        hash_string += "P " + it.first + "=" + it.second.as_string() + "\n";
 
-               for (auto &it : cell->connections) {
+               const std::map<RTLIL::IdString, RTLIL::SigSpec> *conn = &cell->connections;
+               std::map<RTLIL::IdString, RTLIL::SigSpec> alt_conn;
+
+               if (cell->type == "$and" || cell->type == "$or" || cell->type == "$xor" || cell->type == "$xnor" || cell->type == "$add" || cell->type == "$mul" ||
+                               cell->type == "$logic_and" || cell->type == "$logic_or" || cell->type == "$_AND_" || cell->type == "$_OR_" || cell->type == "$_XOR_") {
+                       alt_conn = *conn;
+                       if (assign_map(alt_conn.at("\\A")) < assign_map(alt_conn.at("\\B"))) {
+                               alt_conn["\\A"] = conn->at("\\B");
+                               alt_conn["\\B"] = conn->at("\\A");
+                       }
+                       conn = &alt_conn;
+               }
+
+               for (auto &it : *conn) {
                        if (ct.cell_output(cell->type, it.first))
                                continue;
                        RTLIL::SigSpec sig = it.second;
@@ -126,6 +139,20 @@ struct OptShareWorker
                                assign_map.apply(it.second);
                }
 
+               if (cell1->type == "$and" || cell1->type == "$or" || cell1->type == "$xor" || cell1->type == "$xnor" || cell1->type == "$add" || cell1->type == "$mul" ||
+                               cell1->type == "$logic_and" || cell1->type == "$logic_or" || cell1->type == "$_AND_" || cell1->type == "$_OR_" || cell1->type == "$_XOR_") {
+                       if (conn1.at("\\A") < conn1.at("\\B")) {
+                               RTLIL::SigSpec tmp = conn1["\\A"];
+                               conn1["\\A"] = conn1["\\B"];
+                               conn1["\\B"] = tmp;
+                       }
+                       if (conn2.at("\\A") < conn2.at("\\B")) {
+                               RTLIL::SigSpec tmp = conn2["\\A"];
+                               conn2["\\A"] = conn2["\\B"];
+                               conn2["\\B"] = tmp;
+                       }
+               }
+
                if (conn1 != conn2) {
                        lt = conn1 < conn2;
                        return true;