3 files changed, 20 insertions, 58 deletions

diff --git a/backends/aiger/xaiger.cc b/backends/aiger/xaiger.cc
index 32b218a22..5aea70f3b 100644
--- a/backends/aiger/xaiger.cc
+++ b/backends/aiger/xaiger.cc
@@ -332,13 +332,14 @@ struct XAigerWriter
 				}
 			}
 
-			// Fully pad all unused input connections of this box cell with S0
-			// Fully pad all undriven output connections of this box cell with anonymous wires
 			for (auto port_name : r.first->second) {
 				auto w = box_module->wire(port_name);
 				log_assert(w);
-				auto rhs = cell->getPort(port_name);
-				if (w->port_input)
+
+				SigSpec rhs = cell->connections_.at(port_name, SigSpec());
+				if (w->port_input) {
+					// Add padding to fill entire port
+					rhs.append(SigSpec(State::Sx, GetSize(w)-GetSize(rhs)));
 					for (auto b : rhs) {
 						SigBit I = sigmap(b);
 						if (b == RTLIL::Sx)
@@ -352,14 +353,18 @@ struct XAigerWriter
 						co_bits.emplace_back(b);
 						unused_bits.erase(I);
 					}
-				if (w->port_output)
-					for (const auto &b : rhs.bits()) {
+				}
+				if (w->port_output) {
+					// Add padding to fill entire port
+					rhs.append(SigSpec(State::Sx, GetSize(w)-GetSize(rhs)));
+					for (const auto &b : rhs) {
 						SigBit O = sigmap(b);
 						if (O != b)
 							alias_map[O] = b;
 						ci_bits.emplace_back(b);
 						undriven_bits.erase(O);
 					}
+				}
 			}
 
 			// Connect <cell>.abc9_ff.Q (inserted by abc9_map.v) as the last input to the flop box
@@ -418,8 +423,11 @@ struct XAigerWriter
 
 		for (auto &bit : ci_bits) {
 			aig_m++, aig_i++;
-			log_assert(!aig_map.count(bit));
-			aig_map[bit] = 2*aig_m;
+			// State::Sx if padding
+			if (bit != State::Sx) {
+				log_assert(!aig_map.count(bit));
+				aig_map[bit] = 2*aig_m;
+			}
 		}
 
 		for (auto bit : co_bits) {
@@ -609,8 +617,6 @@ struct XAigerWriter
 			f.write(buffer_str.data(), buffer_str.size());
 
 			if (holes_module) {
-				log_module(holes_module);
-
 				std::stringstream a_buffer;
 				XAigerWriter writer(holes_module);
 				writer.write_aiger(a_buffer, false /*ascii_mode*/);
diff --git a/passes/techmap/abc9_map.cc b/passes/techmap/abc9_map.cc
index b3642ab22..e061cadeb 100644
--- a/passes/techmap/abc9_map.cc
+++ b/passes/techmap/abc9_map.cc
@@ -445,24 +445,19 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *module, std::string scrip
 			if (existing_cell) {
 				cell->parameters = existing_cell->parameters;
 				cell->attributes = existing_cell->attributes;
+				if (cell->attributes.erase("\\abc9_box_seq")) {
+					module->swap_names(cell, existing_cell);
+					module->remove(existing_cell);
+				}
 			}
 			else {
 				cell->parameters = mapped_cell->parameters;
 				cell->attributes = mapped_cell->attributes;
 			}
 
-			auto abc9_box = cell->attributes.erase("\\abc9_box_seq");
-			if (abc9_box) {
-				module->swap_names(cell, existing_cell);
-				module->remove(existing_cell);
-			}
 			RTLIL::Module* box_module = design->module(mapped_cell->type);
 			auto abc9_flop = box_module && box_module->attributes.count("\\abc9_flop");
 			for (auto &conn : mapped_cell->connections()) {
-				// Skip entire box ports composed entirely of padding only
-				if (abc9_box && conn.second.is_wire() && conn.second.as_wire()->get_bool_attribute(ID(abc9_padding)))
-					continue;
-
 				RTLIL::SigSpec newsig;
 				for (auto c : conn.second.chunks()) {
 					if (c.width == 0)
diff --git a/passes/techmap/abc9_ops.cc b/passes/techmap/abc9_ops.cc
index ab5aa9f8d..730431ebf 100644
--- a/passes/techmap/abc9_ops.cc
+++ b/passes/techmap/abc9_ops.cc
@@ -254,45 +254,6 @@ void prep_holes(RTLIL::Module *module, bool dff)
 		RTLIL::Module* box_module = design->module(cell->type);
 		if (!box_module || !box_module->attributes.count("\\abc9_box_id"))
 			continue;
-
-		bool blackbox = box_module->get_blackbox_attribute(true /* ignore_wb */);
-
-		// Fully pad all unused input connections of this box cell with S0
-		// Fully pad all undriven output connections of this box cell with anonymous wires
-		for (const auto &port_name : box_module->ports) {
-			RTLIL::Wire* w = box_module->wire(port_name);
-			log_assert(w);
-			auto it = cell->connections_.find(port_name);
-			if (w->port_input) {
-				RTLIL::SigSpec rhs;
-				if (it != cell->connections_.end()) {
-					if (GetSize(it->second) < GetSize(w))
-						it->second.append(RTLIL::SigSpec(State::S0, GetSize(w)-GetSize(it->second)));
-					rhs = it->second;
-				}
-				else {
-					rhs = RTLIL::SigSpec(State::S0, GetSize(w));
-					cell->setPort(port_name, rhs);
-				}
-			}
-			if (w->port_output) {
-				RTLIL::SigSpec rhs;
-				auto it = cell->connections_.find(w->name);
-				if (it != cell->connections_.end()) {
-					if (GetSize(it->second) < GetSize(w))
-						it->second.append(module->addWire(NEW_ID, GetSize(w)-GetSize(it->second)));
-					rhs = it->second;
-				}
-				else {
-					Wire *wire = module->addWire(NEW_ID, GetSize(w));
-					if (blackbox)
-						wire->set_bool_attribute(ID(abc9_padding));
-					rhs = wire;
-					cell->setPort(port_name, rhs);
-				}
-			}
-		}
-
 		cell->attributes["\\abc9_box_seq"] = box_list.size();
 		box_list.emplace_back(cell);
 	}