From c421d48d6d5519b24b4596d695c3cf7c43b468f4 Mon Sep 17 00:00:00 2001
From: Eddie Hung <eddie@fpgeh.com>
Date: Thu, 20 Jun 2019 19:27:00 -0700
Subject: [PATCH] Fix broken abc9.v test due to inout being 1'bx

---
 backends/aiger/xaiger.cc      | 13 +++++++++++--
 frontends/aiger/aigerparse.cc | 13 ++++++++++---
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/backends/aiger/xaiger.cc b/backends/aiger/xaiger.cc
index 42f54209b..f0a9ccdb9 100644
--- a/backends/aiger/xaiger.cc
+++ b/backends/aiger/xaiger.cc
@@ -75,6 +75,7 @@ struct XAigerWriter
 	dict<SigBit, int> ordered_outputs;
 
 	vector<Cell*> box_list;
+	bool omode = false;
 
 	int mkgate(int a0, int a1)
 	{
@@ -409,9 +410,9 @@ struct XAigerWriter
 			// If encountering an inout port, or a keep-ed wire, then create a new wire
 			// with $inout.out suffix, make it a PO driven by the existing inout, and
 			// inherit existing inout's drivers
-			if ((wire->port_input && wire->port_output && !undriven_bits.count(bit))
+			if ((wire->port_input && wire->port_output && output_bits.count(bit) && !undriven_bits.count(bit))
 					|| wire->attributes.count("\\keep")) {
-				log_assert(input_bits.count(bit) && output_bits.count(bit));
+				log_assert(output_bits.count(bit));
 				RTLIL::IdString wire_name = wire->name.str() + "$inout.out";
 				RTLIL::Wire *new_wire = module->wire(wire_name);
 				if (!new_wire)
@@ -486,6 +487,12 @@ struct XAigerWriter
 			ordered_outputs[bit] = aig_o++;
 			aig_outputs.push_back(bit2aig(bit));
 		}
+
+		if (output_bits.empty()) {
+			aig_o++;
+			aig_outputs.push_back(0);
+			omode = true;
+		}
 	}
 
 	void write_aiger(std::ostream &f, bool ascii_mode)
@@ -741,6 +748,8 @@ struct XAigerWriter
 		for (auto &it : output_lines)
 			f << it.second;
 		log_assert(output_lines.size() == output_bits.size());
+		if (omode && output_bits.empty())
+			f << "output " << output_lines.size() << " 0 $__dummy__\n";
 
 		wire_lines.sort();
 		for (auto &it : wire_lines)
diff --git a/frontends/aiger/aigerparse.cc b/frontends/aiger/aigerparse.cc
index 1235af142..d50a38b7a 100644
--- a/frontends/aiger/aigerparse.cc
+++ b/frontends/aiger/aigerparse.cc
@@ -836,6 +836,10 @@ void AigerReader::post_process()
 				RTLIL::Wire* wire = outputs[variable + co_count];
 				log_assert(wire);
 				log_assert(wire->port_output);
+				if (escaped_s == "$__dummy__") {
+					wire->port_output = false;
+					continue;
+				}
 
 				if (index == 0) {
 					// Cope with the fact that a CO might be identical
@@ -945,12 +949,15 @@ void AigerReader::post_process()
 				other_wire->port_input = false;
 				other_wire->port_output = false;
 			}
-			if (wire->port_input && other_wire)
-				module->connect(other_wire, SigSpec(wire, i));
-			else
+			if (wire->port_input) {
+				if (other_wire)
+					module->connect(other_wire, SigSpec(wire, i));
+			}
+			else {
 								  // Since we skip POs that are connected to Sx,
 								  // re-connect them here
 				module->connect(SigSpec(wire, i), other_wire ? other_wire : SigSpec(RTLIL::Sx));
+			}
 		}
 	}
 
-- 
2.30.2