From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM
	autolearn=unavailable autolearn_force=no version=3.4.4
X-Received: by 10.129.154.215 with SMTP id r206mr16703806ywg.35.1467369637946;
        Fri, 01 Jul 2016 03:40:37 -0700 (PDT)
X-Received: by 10.157.39.133 with SMTP id c5mr766436otb.6.1467369637875; Fri,
 01 Jul 2016 03:40:37 -0700 (PDT)
Path: 
 eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!mx02.eternal-september.org!feeder.eternal-september.org!news.glorb.com!jk6no8191560igb.0!news-out.google.com!d62ni8775ith.0!nntp.google.com!jk6no8191550igb.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail
Newsgroups: comp.lang.ada
Date: Fri, 1 Jul 2016 03:40:37 -0700 (PDT)
In-Reply-To: <dtjpj8Fsm6rU1@mid.individual.net>
Complaints-To: groups-abuse@google.com
Injection-Info: glegroupsg2000goo.googlegroups.com;
 posting-host=2601:191:8202:8510:5985:2c17:9409:aa9c;
 posting-account=fdRd8woAAADTIlxCu9FgvDrUK4wPzvy3
NNTP-Posting-Host: 2601:191:8202:8510:5985:2c17:9409:aa9c
References: <57346ac8$0$4570$426a74cc@news.free.fr>
 <nh2ugj$k6r$1@dont-email.me>
 <nkpgrl$1r41$1@gioia.aioe.org>
 <bd07cd4b-6bfc-4cd0-83b9-a53bb3e7ecea@googlegroups.com>
 <dthecrFe9fjU1@mid.individual.net> <nl03f9$9mi$1@dont-email.me>
 <dtifmjFl15cU1@mid.individual.net> <wccr3bfu496.fsf@TheWorld.com>
 <dtjpj8Fsm6rU1@mid.individual.net>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <d08efdc7-e640-4963-a527-3d033eefb979@googlegroups.com>
Subject: Re: Ada.Strings.Fixed.Count raises Storage_Error
From: rieachus@comcast.net
Injection-Date: Fri, 01 Jul 2016 10:40:37 +0000
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Xref: news.eternal-september.org comp.lang.ada:30987
Date: 2016-07-01T03:40:37-07:00
List-Id: <comp.lang.ada>

On Thursday, June 30, 2016 at 1:38:50 AM UTC-4, Niklas Holsti wrote:

> Regarding Rosen's pathology, your explanation shows that it was a severe=
=20
> one and really required a change in the language definition. A different=
=20
> kind of thing than the possible problems of Strings extending to=20
> Integer'Last.

No it is not.  There was a huge amount of wrangling about the consequences =
of the type Integer being 16-bits in size in Ada 83.  The classic issue was=
 that code for loops generated normally would never terminate for a loop ov=
er Integer'Range.  (Strings were fine because they began at +1.)

Over the next few years, it became common for even Ada compilers for 16-bit=
 word size systems to support a 32-bit Integer type. Then came machines wit=
h 64-bit integer registers and operations, and now, RM 3.5.4(11), Integer i=
s a constrained subtype, and 64-bit registers can be used to count Integer =
loops without a problem.  But the problem does come back for 64-bit or 128-=
bit or whatever types.  No one is going to write a test which would outlast=
 the physical machine, so we can ignore the issue--sort of.  You can go wri=
te a loop that runs from System.Min_Int .. System.Max_Int and inspect the c=
ode generated to see if it is correct.

I consider this issue to be a subcase of this pathology.  On machines with =
64-bit registers and a 32-bit Integer type, the generated code should be fi=
ne.