Re: GNU/GCC optimizing

From	Francois LE COAT <lecoat@atari.org>
Newsgroups	comp.sys.atari.st
Subject	Re: GNU/GCC optimizing
Date	2015-10-01 21:41 +0200
Organization	Aioe.org NNTP Server
Message-ID	<muk29r$54f$1@speranza.aioe.org> (permalink)
References	<muhl54$j6j$1@speranza.aioe.org> <7fb0eab8-e178-47b2-836a-6c86c16bb843@googlegroups.com>

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Hi MiKRO,

Miro Kropáček writes:
>> sources successfully. Large parts of what it's written in C language
>> are completely discarded from the binary even if I use the "-O0" option.
>>
>> Is there a way to force GNU/GCC 4 (I'm experimenting 4.6.4 version) to
>> build strictly what it is written in C, preventing from optimizations ?
>>
> What does that even mean? How discarded? You rely on dead code?
>
> The main change in the 4.x series is introduction of so called strict aliasing, see for instance here: http://cellperformance.beyond3d.com/articles/2006/06/understanding-strict-aliasing.html. You can disable it via a command line switch, however, this is recommended only as a temporary workaround.
>
> Also, some code example would clarify more.

Well, I took GNU/GCC 4.6.4 available on your WEB page at :
<http://mikro.naprvyraz.sk/files/gcc/gcc-4.6.4-m68020-60mint.tar.bz2>
precisely `cc1` binary available in this archive, because I have a
Hades060 machine. I replaced the `cc1` binary from my GNU/GCC 3.3.6
configuration available at <http://eureka.atari.org/gcc3.3.6SDK.zip>
from your `cc1` binary. I have then a GNU/GCC 3.3.6 configuration,
with the C compiler from 4.6.4 version.

With this development configuration, I successfully built Eureka 2.12,
with not so much warnings. The problem is the resulting binary is not
conform to sources. Please keep in mind that my Eureka 2.12 requires
the "-mshort" option from GNU/GCC for PURE C 1.1 compatibility issue.

This weird manipulation was intended to prove that the compatibility
problem from GNU/GCC 3 to GNU/GCC 4 is only due to the `cc1` compiler.
Also, with the available 4.6.4 version, there's no 16bits libraries.

I also put in the `Makefile` a "-O0" compiling option. The problem is
that resulting binary is misbehaving compared to the 3.3.6 compilation.

I don't know what to do. I also tested the cross-compiler under OS X.
My sources seem to be totally misinterpreted by GNU/GCC 4, I'm afraid.

You may have an opinion ...

Thanks for your answer.

Best regards,

-- 
François LE COAT
Author of Eureka 2.12 (2D Graph Describer, 3D Modeller)
http://eureka.atari.org/

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GNU/GCC optimizing Francois LE COAT <lecoat@atari.org> - 2015-09-30 23:45 +0200
  Re: GNU/GCC optimizing Miro Kropáček <miro.kropacek@gmail.com> - 2015-09-30 23:18 -0700
    Re: GNU/GCC optimizing Francois LE COAT <lecoat@atari.org> - 2015-10-01 21:41 +0200
      Re: GNU/GCC optimizing Miro Kropáček <miro.kropacek@gmail.com> - 2015-10-01 23:12 -0700
        Re: GNU/GCC optimizing Francois LE COAT <lecoat@atari.org> - 2015-10-03 16:07 +0200
          Re: GNU/GCC optimizing Michael Schwingen <news-1326478115@discworld.dascon.de> - 2015-10-03 22:20 +0000
            Re: GNU/GCC optimizing Francois LE COAT <lecoat@atari.org> - 2015-10-04 15:15 +0200
              Re: GNU/GCC optimizing Michael Schwingen <news-1326478115@discworld.dascon.de> - 2015-10-04 18:19 +0000
                Re: GNU/GCC optimizing Francois LE COAT <lecoat@atari.org> - 2015-10-04 22:30 +0200
                Re: GNU/GCC optimizing Michael Schwingen <news-1326478115@discworld.dascon.de> - 2015-10-06 16:38 +0000
                Re: GNU/GCC optimizing Francois LE COAT <lecoat@atari.org> - 2015-10-06 21:51 +0200
                Re: GNU/GCC optimizing Michael Schwingen <news-1326478115@discworld.dascon.de> - 2015-10-07 06:55 +0000
              Re: GNU/GCC optimizing David Wade <dave.g4ugm@gmail.com> - 2015-10-04 21:20 +0100
                Re: GNU/GCC optimizing Francois LE COAT <lecoat@atari.org> - 2015-10-04 23:35 +0200
                Re: GNU/GCC optimizing Miro Kropáček <miro.kropacek@gmail.com> - 2015-10-05 02:36 -0700
                Re: GNU/GCC optimizing Francois LE COAT <lecoat@atari.org> - 2015-10-08 21:31 +0200
                Re: GNU/GCC optimizing Miro Kropáček <miro.kropacek@gmail.com> - 2015-10-08 23:55 -0700
                Re: GNU/GCC optimizing Francois LE COAT <lecoat@atari.org> - 2015-10-09 17:25 +0200
                Re: GNU/GCC optimizing Michael Schwingen <news-1326478115@discworld.dascon.de> - 2015-10-10 09:40 +0000
                Re: GNU/GCC optimizing Francois LE COAT <lecoat@atari.org> - 2015-10-10 13:07 +0200

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