Ada RM requires numeric functions to return values in specific ranges, and
specific values for some specified argument values. Many of these are now
translated as Ada 2012 Post aspects on numeric functions.

Tested on x86_64-pc-linux-gnu, committed on trunk

2012-05-15  Yannick Moy  <m...@adacore.com>

        * a-ngelfu.ads: Add postconditions using Ada 2012
        aspect syntax, reflecting some of the RM requirements for these
        functions, from Annex A.5.1 or G.2.4.

Index: a-ngelfu.ads
===================================================================
--- a-ngelfu.ads        (revision 187522)
+++ a-ngelfu.ads        (working copy)
@@ -6,11 +6,35 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
+--              Copyright (C) 2012, Free Software Foundation, Inc.         --
+--                                                                          --
 -- This specification is derived from the Ada Reference Manual for use with --
--- GNAT.  In accordance with the copyright of that document, you can freely --
--- copy and modify this specification,  provided that if you redistribute a --
--- modified version,  any changes that you have made are clearly indicated. --
+-- GNAT. The copyright notice above, and the license provisions that follow --
+-- apply solely to the Post aspects that have been added to the spec.       --
+-- Except for these parts of the document, in accordance with the copyright --
+-- of that document,  you can  freely copy and  modify this  specification, --
+-- provided that  if you redistribute a modified version,  any changes that --
+-- you have made are clearly indicated.                                     --
 --                                                                          --
+-- GNAT is free software;  you can  redistribute it  and/or modify it under --
+-- terms of the  GNU General Public License as published  by the Free Soft- --
+-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
+-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
+-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
+-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
+--                                                                          --
+-- As a special exception under Section 7 of GPL version 3, you are granted --
+-- additional permissions described in the GCC Runtime Library Exception,   --
+-- version 3.1, as published by the Free Software Foundation.               --
+--                                                                          --
+-- You should have received a copy of the GNU General Public License and    --
+-- a copy of the GCC Runtime Library Exception along with this program;     --
+-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
+-- <http://www.gnu.org/licenses/>.                                          --
+--                                                                          --
+-- GNAT was originally developed  by the GNAT team at  New York University. --
+-- Extensive contributions were provided by Ada Core Technologies Inc.      --
+--                                                                          --
 ------------------------------------------------------------------------------
 
 generic
@@ -19,55 +43,141 @@
 package Ada.Numerics.Generic_Elementary_Functions is
    pragma Pure;
 
-   function Sqrt    (X           : Float_Type'Base) return Float_Type'Base;
-   function Log     (X           : Float_Type'Base) return Float_Type'Base;
-   function Log     (X, Base     : Float_Type'Base) return Float_Type'Base;
-   function Exp     (X           : Float_Type'Base) return Float_Type'Base;
-   function "**"    (Left, Right : Float_Type'Base) return Float_Type'Base;
+   function Sqrt (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => Sqrt'Result >= 0.0
+       and then (if X = 0.0 then Sqrt'Result = 0.0)
+       and then (if X = 1.0 then Sqrt'Result = 1.0);
 
-   function Sin     (X           : Float_Type'Base) return Float_Type'Base;
-   function Sin     (X, Cycle    : Float_Type'Base) return Float_Type'Base;
-   function Cos     (X           : Float_Type'Base) return Float_Type'Base;
-   function Cos     (X, Cycle    : Float_Type'Base) return Float_Type'Base;
-   function Tan     (X           : Float_Type'Base) return Float_Type'Base;
-   function Tan     (X, Cycle    : Float_Type'Base) return Float_Type'Base;
-   function Cot     (X           : Float_Type'Base) return Float_Type'Base;
-   function Cot     (X, Cycle    : Float_Type'Base) return Float_Type'Base;
+   function Log (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => (if X = 1.0 then Log'Result = 0.0);
 
-   function Arcsin  (X           : Float_Type'Base) return Float_Type'Base;
-   function Arcsin  (X, Cycle    : Float_Type'Base) return Float_Type'Base;
-   function Arccos  (X           : Float_Type'Base) return Float_Type'Base;
-   function Arccos  (X, Cycle    : Float_Type'Base) return Float_Type'Base;
+   function Log (X, Base : Float_Type'Base) return Float_Type'Base
+   with
+     Post => (if X = 1.0 then Log'Result = 0.0);
 
+   function Exp (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => (if X = 0.0 then Exp'Result = 1.0);
+
+   function "**" (Left, Right : Float_Type'Base) return Float_Type'Base
+   with
+     Post => "**"'Result >= 0.0
+       and then (if Right = 0.0 then "**"'Result = 1.0)
+       and then (if Right = 1.0 then "**"'Result = Left)
+       and then (if Left = 1.0 then "**"'Result = 1.0)
+       and then (if Left = 0.0 then "**"'Result = 0.0);
+
+   function Sin (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => Sin'Result in -1.0 .. 1.0
+       and then (if X = 0.0 then Sin'Result = 0.0);
+
+   function Sin (X, Cycle : Float_Type'Base) return Float_Type'Base
+   with
+     Post => Sin'Result in -1.0 .. 1.0
+       and then (if X = 0.0 then Sin'Result = 0.0);
+
+   function Cos (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => Cos'Result in -1.0 .. 1.0
+       and then (if X = 0.0 then Cos'Result = 1.0);
+
+   function Cos (X, Cycle : Float_Type'Base) return Float_Type'Base
+   with
+     Post => Cos'Result in -1.0 .. 1.0
+       and then  (if X = 0.0 then Cos'Result = 1.0);
+
+   function Tan (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => (if X = 0.0 then Tan'Result = 0.0);
+
+   function Tan (X, Cycle : Float_Type'Base) return Float_Type'Base
+   with
+     Post => (if X = 0.0 then Tan'Result = 0.0);
+
+   function Cot (X : Float_Type'Base) return Float_Type'Base;
+
+   function Cot (X, Cycle : Float_Type'Base) return Float_Type'Base;
+
+   function Arcsin (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => (if X = 0.0 then Arcsin'Result = 0.0);
+
+   function Arcsin (X, Cycle : Float_Type'Base) return Float_Type'Base
+   with
+     Post => (if X = 0.0 then Arcsin'Result = 0.0);
+
+   function Arccos (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => (if X = 1.0 then Arccos'Result = 0.0);
+
+   function Arccos (X, Cycle : Float_Type'Base) return Float_Type'Base
+   with
+     Post => (if X = 1.0 then Arccos'Result = 0.0);
+
    function Arctan
      (Y   : Float_Type'Base;
       X   : Float_Type'Base := 1.0)
-     return Float_Type'Base;
+     return Float_Type'Base
+   with
+     Post => (if X > 0.0 and Y = 0.0 then Arctan'Result = 0.0);
 
    function Arctan
      (Y     : Float_Type'Base;
       X     : Float_Type'Base := 1.0;
       Cycle : Float_Type'Base)
-      return  Float_Type'Base;
+      return  Float_Type'Base
+   with
+     Post => (if X > 0.0 and Y = 0.0 then Arctan'Result = 0.0);
 
    function Arccot
      (X   : Float_Type'Base;
       Y   : Float_Type'Base := 1.0)
-     return Float_Type'Base;
+     return Float_Type'Base
+   with
+     Post => (if X > 0.0 and Y = 0.0 then Arccot'Result = 0.0);
 
    function Arccot
      (X     : Float_Type'Base;
       Y     : Float_Type'Base := 1.0;
       Cycle : Float_Type'Base)
-     return   Float_Type'Base;
+     return   Float_Type'Base
+   with
+     Post => (if X > 0.0 and Y = 0.0 then Arccot'Result = 0.0);
 
-   function Sinh    (X : Float_Type'Base) return Float_Type'Base;
-   function Cosh    (X : Float_Type'Base) return Float_Type'Base;
-   function Tanh    (X : Float_Type'Base) return Float_Type'Base;
-   function Coth    (X : Float_Type'Base) return Float_Type'Base;
-   function Arcsinh (X : Float_Type'Base) return Float_Type'Base;
-   function Arccosh (X : Float_Type'Base) return Float_Type'Base;
-   function Arctanh (X : Float_Type'Base) return Float_Type'Base;
+   function Sinh (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => (if X = 0.0 then Sinh'Result = 0.0);
+
+   function Cosh (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => Cosh'Result >= 1.0
+       and then (if X = 0.0 then Cosh'Result = 1.0);
+
+   function Tanh (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => Tanh'Result in -1.0 .. 1.0
+       and then (if X = 0.0 then Tanh'Result = 0.0);
+
+   function Coth (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => abs Coth'Result >= 1.0;
+
+   function Arcsinh (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => (if X = 0.0 then Arcsinh'Result = 0.0);
+
+   function Arccosh (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => Arccosh'Result >= 0.0
+       and then (if X = 1.0 then Arccosh'Result = 0.0);
+
+   function Arctanh (X : Float_Type'Base) return Float_Type'Base
+   with
+     Post => (if X = 0.0 then Arctanh'Result = 0.0);
+
    function Arccoth (X : Float_Type'Base) return Float_Type'Base;
 
 end Ada.Numerics.Generic_Elementary_Functions;

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