From: whitequark <whitequark@whitequark.org>
Date: Sat, 17 Jul 2021 14:23:57 +0000 (+0000)
Subject: cxxrtl: treat internal wires used only for debug as constants.
X-Git-Tag: yosys-0.10~96^2
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=4aa65f406f3f793978278454fe8d8000a442e2f2;p=yosys.git

cxxrtl: treat internal wires used only for debug as constants.

Fixes #2739 (again).
---

diff --git a/backends/cxxrtl/cxxrtl_backend.cc b/backends/cxxrtl/cxxrtl_backend.cc
index 7ff344e66..56305258a 100644
--- a/backends/cxxrtl/cxxrtl_backend.cc
+++ b/backends/cxxrtl/cxxrtl_backend.cc
@@ -2881,6 +2881,12 @@ struct CxxrtlWorker {
 						debug_live_nodes.erase(node);
 					} else if (wire_type.is_local()) {
 						debug_wire_type = {WireType::LOCAL}; // wire not inlinable
+					} else if (wire_type.type == WireType::UNUSED) {
+						if (wire_init.count(wire)) {
+							debug_wire_type = {WireType::CONST, wire_init.at(wire)};
+						} else {
+							debug_wire_type = {WireType::CONST, RTLIL::SigSpec(RTLIL::S0, wire->width)};
+						} // wire never modified
 					} else {
 						log_assert(wire_type.is_member());
 						debug_wire_type = wire_type; // wire is a member