iopadmap: Fix z assignment removal.

Fixes #3360.

diff --git a/passes/techmap/iopadmap.cc b/passes/techmap/iopadmap.cc
index 437ad51561bda2e86f50ab49bf694be83a078dbd..322eb7779ac068fbb2f49552827ec0ee8c9e4189 100644 (file)
--- a/passes/techmap/iopadmap.cc
+++ b/passes/techmap/iopadmap.cc
@@ -240,13 +240,13 @@ struct IopadmapPass : public Pass {
                for (auto module : design->selected_modules())
                {
                        dict<Wire *, dict<int, pair<Cell *, IdString>>> rewrite_bits;
-                       pool<SigSig> remove_conns;
+                       dict<SigSig, pool<int>> remove_conns;
 
                        if (!toutpad_celltype.empty() || !tinoutpad_celltype.empty())
                        {
                                dict<SigBit, Cell *> tbuf_bits;
                                pool<SigBit> driven_bits;
-                               dict<SigBit, SigSig> z_conns;
+                               dict<SigBit, std::pair<SigSig, int>> z_conns;
 
                                // Gather tristate buffers and always-on drivers.
                                for (auto cell : module->cells())
@@ -266,7 +266,7 @@ struct IopadmapPass : public Pass {
                                                SigBit dstbit = conn.first[i];
                                                SigBit srcbit = conn.second[i];
                                                if (!srcbit.wire && srcbit.data == State::Sz) {
-                                                       z_conns[dstbit] = conn;
+                                                       z_conns[dstbit] = {conn, i};
                                                        continue;
                                                }
                                                driven_bits.insert(dstbit);
@@ -317,8 +317,9 @@ struct IopadmapPass : public Pass {
                                                        // enable.
                                                        en_sig = SigBit(State::S0);
                                                        data_sig = SigBit(State::Sx);
-                                                       if (z_conns.count(wire_bit))
-                                                               remove_conns.insert(z_conns[wire_bit]);
+                                                       auto it = z_conns.find(wire_bit);
+                                                       if (it != z_conns.end())
+                                                               remove_conns[it->second.first].insert(it->second.second);
                                                }
 
                                                if (wire->port_input)
@@ -477,9 +478,22 @@ struct IopadmapPass : public Pass {
 
                        if (!remove_conns.empty()) {
                                std::vector<SigSig> new_conns;
-                               for (auto &conn : module->connections())
-                                       if (!remove_conns.count(conn))
+                               for (auto &conn : module->connections()) {
+                                       auto it = remove_conns.find(conn);
+                                       if (it == remove_conns.end()) {
                                                new_conns.push_back(conn);
+                                       } else {
+                                               SigSpec lhs, rhs;
+                                               for (int i = 0; i < GetSize(conn.first); i++) {
+                                                       if (!it->second.count(i)) {
+                                                               lhs.append(conn.first[i]);
+                                                               rhs.append(conn.second[i]);
+                                                       }
+                                               }
+                                               new_conns.push_back(SigSig(lhs, rhs));
+
+                                       }
+                               }
                                module->new_connections(new_conns);
                        }