From f3f8037328af023d0c1852e4a6c2afa9f2473f30 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Povi=C5=A1er?= <povik@cutebit.org>
Date: Thu, 5 Dec 2024 16:19:55 +0100
Subject: [PATCH] abc9_ops: Allow no arcs on box w/o inputs or w/o outputs

---
 passes/techmap/abc9_ops.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/passes/techmap/abc9_ops.cc b/passes/techmap/abc9_ops.cc
index 6c8319f9f2d..c4137c1c895 100644
--- a/passes/techmap/abc9_ops.cc
+++ b/passes/techmap/abc9_ops.cc
@@ -1093,8 +1093,9 @@ void prep_box(RTLIL::Design *design)
 			ss << std::endl;
 
 			auto &t = timing.setup_module(module);
-			if (t.comb.empty())
+			if (t.comb.empty() && !outputs.empty() && !inputs.empty()) {
 				log_error("Module '%s' with (* abc9_box *) has no timing (and thus no connectivity) information.\n", log_id(module));
+			}
 
 			for (const auto &o : outputs) {
 				first = true;