From 55189bc65cab819fd2014b7194a49e9d1829f77d Mon Sep 17 00:00:00 2001
From: "Emil J. Tywoniak" <emil@tywoniak.eu>
Date: Tue, 17 Mar 2026 18:04:41 +0100
Subject: [PATCH] flatten: redo signormalization to work around fanout issue

---
 passes/cmds/rename.cc       | 3 +++
 passes/hierarchy/flatten.cc | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/passes/cmds/rename.cc b/passes/cmds/rename.cc
index 078ffb769..0f055b81d 100644
--- a/passes/cmds/rename.cc
+++ b/passes/cmds/rename.cc
@@ -379,6 +379,9 @@ struct RenamePass : public Pass {
 			break;
 		}
 
+		// TODO disable signorm due to rename I think?
+		design->sigNormalize(false);
+
 		if (flag_src)
 		{
 			extra_args(args, argidx, design);
diff --git a/passes/hierarchy/flatten.cc b/passes/hierarchy/flatten.cc
index 9ee410589..584370304 100644
--- a/passes/hierarchy/flatten.cc
+++ b/passes/hierarchy/flatten.cc
@@ -410,6 +410,8 @@ struct FlattenPass : public Pass {
 		}
 		extra_args(args, argidx, design);
 
+		bool was_signormed = design->flagSigNormalized;
+
 		RTLIL::Module *top = nullptr;
 		if (design->full_selection())
 			for (auto module : design->modules())
@@ -449,6 +451,11 @@ struct FlattenPass : public Pass {
 					design->remove(module);
 				}
 
+		if (was_signormed) {
+			// TODO inconvenient workaround for fanout out of sync
+			design->sigNormalize(false);
+			design->sigNormalize(true);
+		}
 		log_pop();
 	}
 } FlattenPass;