From 5f6a838823d0468cd055ca4aeaa96d5a7b79eca1 Mon Sep 17 00:00:00 2001
From: Clifford Wolf <clifford@clifford.at>
Date: Sat, 8 Oct 2016 12:25:34 +0200
Subject: [PATCH] Added smtc support for top-level state with [], [N:] syntax

---
 backends/smt2/smtbmc.py | 2 +-
 backends/smt2/smtio.py  | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/backends/smt2/smtbmc.py b/backends/smt2/smtbmc.py
index eac693632..0cfb386a1 100644
--- a/backends/smt2/smtbmc.py
+++ b/backends/smt2/smtbmc.py
@@ -249,7 +249,7 @@ def get_constr_expr(db, state, final=False, getvalues=False):
         if state not in db:
             return ([], [], []) if getvalues else "true"
 
-    netref_regex = re.compile(r'(^|[( ])\[(-?[0-9]+:|)([^\]]+)\](?=[ )]|$)')
+    netref_regex = re.compile(r'(^|[( ])\[(-?[0-9]+:|)([^\]]*)\](?=[ )]|$)')
 
     def replace_netref(match):
         state_sel = match.group(2)
diff --git a/backends/smt2/smtio.py b/backends/smt2/smtio.py
index eccb65014..72bd8b178 100644
--- a/backends/smt2/smtio.py
+++ b/backends/smt2/smtio.py
@@ -534,6 +534,8 @@ class SmtIo:
     def net_expr(self, mod, base, path):
         if len(path) == 1:
             assert mod in self.modinfo
+            if path[0] == "":
+                return base
             if path[0] in self.modinfo[mod].cells:
                 return "(|%s_h %s| %s)" % (mod, path[0], base)
             if path[0] in self.modinfo[mod].wsize:
-- 
2.30.2