From 8384460b4baeb62b6c5d93fd6824a7af31cf65fc Mon Sep 17 00:00:00 2001
From: "Emil J. Tywoniak" <emil@tywoniak.eu>
Date: Fri, 15 Aug 2025 11:14:02 +0200
Subject: [PATCH] check: add bufnorm invariant check

---
 passes/cmds/check.cc | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/passes/cmds/check.cc b/passes/cmds/check.cc
index 8bbcb8da0..a90b916e8 100644
--- a/passes/cmds/check.cc
+++ b/passes/cmds/check.cc
@@ -287,6 +287,13 @@ struct CheckPass : public Pass {
 			pool<SigBit> init_bits;
 
 			for (auto wire : module->wires()) {
+				if (design->flagBufferedNormalized) {
+					if (!wire->driverKnown())
+						log_error("Wire %s has no bufnorm driver cell in buffer normalized mode\n", log_id(wire));
+				} else {
+					if (wire->driverKnown())
+						log_error("Wire %s has a bufnorm driver cell outside of buffer normalized mode\n", log_id(wire));
+				}
 				if (wire->port_input) {
 					SigSpec sig = sigmap(wire);
 					for (int i = 0; i < GetSize(sig); i++)