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From: "(see below)" <yaldnif.w@blueyonder.co.uk>
Newsgroups: comp.lang.ada
Subject: Re: Problem with optimizations
Date: Tue, 28 Apr 2009 19:40:07 +0100
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Date: 2009-04-28T19:40:07+01:00
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On 28/04/2009 18:04, in article 49f73730$0$2850$ba620e4c@news.skynet.be,
"Olivier Scalbert" <olivier.scalbert@algosyn.com> wrote:

...
> When, inside the Recursive_Find_Solution, I replace Is_Solved by
> Is_Solved1, then it works in all cases.
> 
> I have try to understand what is happen with gdb and by having a look
> into the generated code, but without success.
> 
> I have the same behaviour with:
> - Ubuntu 8.10 32 bits (GNATMAKE 4.3.2)
> - Debian testing AMD 64bits (GNATMAKE 4.3.3)
> 
> The code can be found there:
> http://scalbert.dyndns.org/adarubik/
> 
> This small project is a really a toy but I would like to understand the
> problem.

There is no else part for the following if:

            if Is_Solved(Cube) then
                New_Line;
                Put("Solved !"); New_Line;

                for i in 1..depth-1 loop
                    Ada.Integer_Text_IO.Put(Integer(Moves(i)));
                end loop;
                Result := True;
            end if;

So the procedure can exit with Result undefined. Since the program is
incorrect, varying optimisation, or implementation details, is likely to
give varying results. Some may co-incidentally be the results you expect.

P.S. I did not use gdb.

-- 
Bill Findlay, <surname><forename> chez blueyonder.co.uk
"My own view on religion is that of Lucretius. I regard it as a disease born
of fear and as a source of untold misery to the human race." B. Russell