Add support for partial matches to muxcover, fixes #1091

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

diff --git a/passes/techmap/muxcover.cc b/passes/techmap/muxcover.cc
index 8e44be148d422f2f4a130e83074f92ad8eb2ed23..78272b0c477636164edbb76a747eb250aebfda6e 100644 (file)
--- a/passes/techmap/muxcover.cc
+++ b/passes/techmap/muxcover.cc
@@ -57,6 +57,7 @@ struct MuxcoverWorker
        bool use_mux8;
        bool use_mux16;
        bool nodecode;
+       bool nopartial;
 
        int cost_mux2;
        int cost_mux4;
@@ -69,6 +70,7 @@ struct MuxcoverWorker
                use_mux8 = false;
                use_mux16 = false;
                nodecode = false;
+               nopartial = false;
                cost_mux2 = COST_MUX2;
                cost_mux4 = COST_MUX4;
                cost_mux8 = COST_MUX8;
@@ -133,13 +135,20 @@ struct MuxcoverWorker
                log("    Finished treeification: Found %d trees.\n", GetSize(tree_list));
        }
 
-       bool follow_muxtree(SigBit &ret_bit, tree_t &tree, SigBit bit, const char *path)
+       bool follow_muxtree(SigBit &ret_bit, tree_t &tree, SigBit bit, const char *path, bool first_layer = true)
        {
                if (*path) {
-                       if (tree.muxes.count(bit) == 0)
-                               return false;
+                       if (tree.muxes.count(bit) == 0) {
+                               if (first_layer || nopartial)
+                                       return false;
+                               if (path[0] == 'S')
+                                       ret_bit = State::Sx;
+                               else
+                                       ret_bit = bit;
+                               return true;
+                       }
                        char port_name[3] = {'\\', *path, 0};
-                       return follow_muxtree(ret_bit, tree, sigmap(tree.muxes.at(bit)->getPort(port_name)), path+1);
+                       return follow_muxtree(ret_bit, tree, sigmap(tree.muxes.at(bit)->getPort(port_name)), path+1, false);
                } else {
                        ret_bit = bit;
                        return true;
@@ -148,7 +157,7 @@ struct MuxcoverWorker
 
        int prepare_decode_mux(SigBit &A, SigBit B, SigBit sel, SigBit bit)
        {
-               if (A == B)
+               if (A == B || sel == State::Sx)
                        return 0;
 
                tuple<SigBit, SigBit, SigBit> key(A, B, sel);
@@ -166,6 +175,9 @@ struct MuxcoverWorker
                if (std::get<2>(entry))
                        return 0;
 
+               if (A == State::Sx || B == State::Sx)
+                       return 0;
+
                return cost_mux2 / GetSize(std::get<1>(entry));
        }
 
@@ -183,9 +195,15 @@ struct MuxcoverWorker
                implement_decode_mux(std::get<0>(key));
                implement_decode_mux(std::get<1>(key));
 
-               module->addMuxGate(NEW_ID, std::get<0>(key), std::get<1>(key), std::get<2>(key), ctrl_bit);
+               if (std::get<0>(key) == State::Sx) {
+                       module->addBufGate(NEW_ID, std::get<1>(key), ctrl_bit);
+               } else if (std::get<1>(key) == State::Sx) {
+                       module->addBufGate(NEW_ID, std::get<0>(key), ctrl_bit);
+               } else {
+                       module->addMuxGate(NEW_ID, std::get<0>(key), std::get<1>(key), std::get<2>(key), ctrl_bit);
+                       decode_mux_counter++;
+               }
                std::get<2>(entry) = true;
-               decode_mux_counter++;
        }
 
        int find_best_cover(tree_t &tree, SigBit bit)
@@ -598,6 +616,7 @@ struct MuxcoverPass : public Pass {
                bool use_mux8 = false;
                bool use_mux16 = false;
                bool nodecode = false;
+               bool nopartial = false;
                int cost_mux4 = COST_MUX4;
                int cost_mux8 = COST_MUX8;
                int cost_mux16 = COST_MUX16;
@@ -634,6 +653,10 @@ struct MuxcoverPass : public Pass {
                                nodecode = true;
                                continue;
                        }
+                       if (arg == "-nopartial") {
+                               nopartial = true;
+                               continue;
+                       }
                        break;
                }
                extra_args(args, argidx, design);
@@ -654,6 +677,7 @@ struct MuxcoverPass : public Pass {
                        worker.cost_mux8 = cost_mux8;
                        worker.cost_mux16 = cost_mux16;
                        worker.nodecode = nodecode;
+                       worker.nopartial = nopartial;
                        worker.run();
                }
        }