From dcd7742d5220a2997eff9c80d699fd44ca2d2305 Mon Sep 17 00:00:00 2001
From: Robert O'Callahan <rocallahan@google.com>
Date: Wed, 21 Jan 2026 04:02:02 +0000
Subject: [PATCH] Avoid scanning entire module if there are no wires to remove

It's pretty common for `opt_clean` to find no wires to remove. In that case,
there is no point scanning the entire design, which can be significantly
expensive for huge designs.
---
 kernel/rtlil.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/rtlil.cc b/kernel/rtlil.cc
index 42d5f56b6..eef1c319d 100644
--- a/kernel/rtlil.cc
+++ b/kernel/rtlil.cc
@@ -2990,6 +2990,8 @@ void RTLIL::Module::add(RTLIL::Binding *binding)
 void RTLIL::Module::remove(const pool<RTLIL::Wire*> &wires)
 {
 	log_assert(refcount_wires_ == 0);
+	if (wires.empty())
+		return;
 
 	struct DeleteWireWorker
 	{