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From: Ludovic Brenta <ludovic@ludovic-brenta.org>
Newsgroups: comp.lang.ada
Subject: Re: Problem with streams using 64-bit compiler
Date: Mon, 4 Jan 2010 15:09:25 -0800 (PST)
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Date: 2010-01-04T15:09:25-08:00
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On Jan 4, 11:46=A0pm, sjw <simon.j.wri...@mac.com> wrote:
> While trying to build a 64-bit compiler for Mac OS X Snow Leopard, I
> came across this undesirable behaviour: if the program (see end) is
> compiled in 32-bit mode or in 64-bit mode with -O0 it works fine,
> output is as expected:
>
> $ ./streamy
> =A01234
> 'z'
> =A04.32100E-01
> =A04.32100E-01
>
> If compiled in 64-bit mode with -O2, output is
>
> $ ./streamy
> 1234
> NUL
> =A00.00000E+00
> =A00.00000E+00
>
> This is a readback problem, the data file has the same content in all
> cases.
>
> Can anyone with access to an x86_64 compiler (Mac OS X Leopard, or a
> Linux, 4.4+) have a try and see what happens?
[...]

I get the same behavior as you on Debian:

gnat-4.4_4.4.2-5_amd64.deb:
 -O0 OK
 -O1 bug
 -O2 bug
gnat-4.4_4.4.2-5_i386.deb:
 -O0 OK
 -O1 OK
 -O2 OK

This version of GNAT is taken from the FSF's gcc-4_4-branch on
2009-12-28 so is very recent.

I suggest you report the bug to http://gcc.gnu.org/bugzilla.  Since
you've got a perfect reproducer test case, the bug should be easy
enough to fix.

Maybe someone else can try GCC 4.5?

--
Ludovic Brenta.