From 1c90997499bb6bc470e3c49ccf51b3e3b8dbfd0b Mon Sep 17 00:00:00 2001
From: Stephen Williams <steve@icarus.com>
Date: Mon, 13 Oct 2008 20:50:56 -0700
Subject: [PATCH] concatentations that reduce to constants need proper
 signed-ness

It is possible, via the use of the $signed() function, for concatenation
expressions to be signed. Make sure the evaluated constant had the
proper sign by checking explicitly.
---
 eval_tree.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/eval_tree.cc b/eval_tree.cc
index 0a0dec69c..be195159f 100644
--- a/eval_tree.cc
+++ b/eval_tree.cc
@@ -1200,6 +1200,11 @@ NetEConst* NetEConcat::eval_tree(int prune_to_width)
 	    val = verinum(val.as_string());
       }
 
+	// Normally, concatenations are unsigned. However, the
+	// $signed() function works by marking the expression as
+	// signed, so we really have to check.
+      val.has_sign( this->has_sign() );
+
       NetEConst*res = new NetEConst(val);
       res->set_width(val.len());
       return res;