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Re: GNU/GCC optimizing

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Hi,

Michael Schwingen writes:
> Francois LE COAT wrote:
>> Well, the starting demo with a spinning hypercube is not played. The
>> GEM interface seems correct, but if I want to describe a curve, the
>> curve is not drawn. If I want to draw a surface, the surface is
>> not drawn. Nothing happens with the binary like it should. The
>> binary is simply not corresponding to sources. The program is broken.
>
> Im my experience with optimizing compilers, in most such cases the fault is
> not with the compiler, but instead the source code is broken, doing things
> that are not allowed by the C standard and relying on undefined behaviour.
>
> If it worked with the older compiler (that had a weaker optimizer) that does
> not mean anything for the correctness of the source code.
>
> Did you compile with all warning enabled, and look at the warnings? I can't
> believe old, misbehaving code would compile after a gcc3 -> gcc4 switch
> without producing at least some new warnings!

You'll agree that it's very peculiar ... How bizarre a warning will
generate an error when building C program's sources ? This is not
a warning, but should be alerted as an error, don't you think so ?
I never seen before in the C standard definition that a warning
should imperatively be taken into account, otherwise generating an
error. The warnings must often, used to generate good code, not errors.
Strong optimizations mean that warnings are now considered as errors ?

Please take into account that I practice C language since 1986,
first Kernighan and Ritchie, then ANSI C standard. Notice the
C standard must have evoluted because my C sources are now obsolete.

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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