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Groups > comp.sys.atari.st > #1354

Re: GNU/GCC optimizing

Newsgroups comp.sys.atari.st
Date 2015-09-30 23:18 -0700
References <muhl54$j6j$1@speranza.aioe.org>
Message-ID <7fb0eab8-e178-47b2-836a-6c86c16bb843@googlegroups.com> (permalink)
Subject Re: GNU/GCC optimizing
From Miro Kropáček <miro.kropacek@gmail.com>

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> 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.

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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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