From e6073d5f34b92cb4b7542d0a740be2701e882acf Mon Sep 17 00:00:00 2001
From: Tristan Gingold <tgingold@free.fr>
Date: Wed, 11 Sep 2019 18:50:33 +0200
Subject: synth: handle constant bit compare.

---
 src/synth/synth-expr.adb | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/synth/synth-expr.adb b/src/synth/synth-expr.adb
index d6651638f..ecb2bada1 100644
--- a/src/synth/synth-expr.adb
+++ b/src/synth/synth-expr.adb
@@ -783,8 +783,14 @@ package body Synth.Expr is
       Zx : Uns32;
       N : Net;
    begin
+      if Is_Const (Expr) then
+         return Create_Value_Discrete (Boolean'Pos (Cst.Scal = Expr.Scal),
+                                       Boolean_Type);
+      end if;
+
       To_Logic (Cst.Scal, Cst.Typ, Val, Zx);
       if Zx /= 0 then
+         --  Equal unknown -> return X
          N := Build_Const_UL32 (Build_Context, 0, 1, 1);
          Set_Location (N, Loc);
          return Create_Value_Net (N, Boolean_Type);
-- 
cgit v1.2.3