From a2c0447aeb1e1b3fca1d84716a2a97a5f65d3c30 Mon Sep 17 00:00:00 2001
From: Tristan Gingold <tgingold@free.fr>
Date: Tue, 7 May 2019 18:45:33 +0200
Subject: vhdl: Add a warning for null range in discrete type declaration.

For issue #810
---
 src/vhdl/vhdl-evaluation.adb | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

(limited to 'src/vhdl/vhdl-evaluation.adb')

diff --git a/src/vhdl/vhdl-evaluation.adb b/src/vhdl/vhdl-evaluation.adb
index 65d099a42..6363411aa 100644
--- a/src/vhdl/vhdl-evaluation.adb
+++ b/src/vhdl/vhdl-evaluation.adb
@@ -3487,6 +3487,20 @@ package body Vhdl.Evaluation is
       end case;
    end Eval_Discrete_Type_Length;
 
+   function Eval_Is_Null_Discrete_Range (Rng : Iir) return Boolean
+   is
+      Left, Right : Iir_Int64;
+   begin
+      Left := Eval_Pos (Get_Left_Limit (Rng));
+      Right := Eval_Pos (Get_Right_Limit (Rng));
+      case Get_Direction (Rng) is
+         when Iir_To =>
+            return Right < Left;
+         when Iir_Downto =>
+            return Left < Right;
+      end case;
+   end Eval_Is_Null_Discrete_Range;
+
    function Eval_Pos (Expr : Iir) return Iir_Int64 is
    begin
       case Get_Kind (Expr) is
-- 
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