From 66b2fdc8e4246a9f4f7aaa2c2dd8db01fc4d2942 Mon Sep 17 00:00:00 2001
From: "Emil J. Tywoniak" <emil@tywoniak.eu>
Date: Thu, 17 Sep 2026 15:41:05 +0200
Subject: [PATCH] write_smt2: ignore $input_port

---
 backends/smt2/smt2.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/backends/smt2/smt2.cc b/backends/smt2/smt2.cc
index 40587edae..7ac2faf87 100644
--- a/backends/smt2/smt2.cc
+++ b/backends/smt2/smt2.cc
@@ -938,6 +938,9 @@ struct Smt2Worker
 			log_error("Unsupported cell type %s for cell %s.%s -- please run `clk2fflogic` before `write_smt2`.\n",
 					cell->type, module, cell);
 		}
+
+		if (cell->type == ID($input_port)) return;
+
 		log_error("Unsupported cell type %s for cell %s.%s.\n",
 				cell->type, module, cell);
 	}