From 412332fdb3697c48b5e9f575933f45704e82df3c Mon Sep 17 00:00:00 2001
From: Miodrag Milanovic <mmicko@gmail.com>
Date: Fri, 25 Sep 2020 11:40:37 +0200
Subject: [PATCH] Validate parameters only when they are used

---
 passes/hierarchy/hierarchy.cc | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/passes/hierarchy/hierarchy.cc b/passes/hierarchy/hierarchy.cc
index 90b25949d..225e1feae 100644
--- a/passes/hierarchy/hierarchy.cc
+++ b/passes/hierarchy/hierarchy.cc
@@ -765,11 +765,13 @@ struct HierarchyPass : public Pass {
 			top_mod = design->module(top_name);
 
 			dict<RTLIL::IdString, RTLIL::Const> top_parameters;
-			for (auto &para : parameters) {
-				SigSpec sig_value;
-				if (!RTLIL::SigSpec::parse(sig_value, NULL, para.second))
-					log_cmd_error("Can't decode value '%s'!\n", para.second.c_str());
-				top_parameters[RTLIL::escape_id(para.first)] = sig_value.as_const();
+			if ((top_mod == nullptr && design->module(abstract_id)) || top_mod != nullptr) {
+				for (auto &para : parameters) {
+					SigSpec sig_value;
+					if (!RTLIL::SigSpec::parse(sig_value, NULL, para.second))
+						log_cmd_error("Can't decode value '%s'!\n", para.second.c_str());
+					top_parameters[RTLIL::escape_id(para.first)] = sig_value.as_const();
+				}
 			}
 
 			if (top_mod == nullptr && design->module(abstract_id))