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Date: Thu, 05 Nov 2009 22:30:35 +0000
From: Dave Korn <dave DOT korn DOT cygwin AT googlemail DOT com>
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To: cygwin AT cygwin DOT com
Subject: Re: status of gcc4 -ffast-math
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Hans Horn wrote:
> Folks,
> 
> what is the current status of -ffast-math for gcc4 under cygwin.
> 
> I tried to use it for some numerical C code and get the following link
> errors:
> 
> eval.o:eval.c:(.text+0x79c): undefined reference to `_f_pow'
> eval.o:eval.c:(.text+0x7d8): undefined reference to `_f_log'
> eval.o:eval.c:(.text+0x7f0): undefined reference to `_f_exp'

  WJFFM:

> $ cat math.c
> 
> #include <math.h>
> 
> int main (int argc, const char **argv)
> {
> 
>   float f = atof (argv[1]);
>   double d = log (f);
>   return exp (f);
> }
> 
> 
> admin AT ubik /tmp/math
> $ gcc-4 math.c -o math
> 
> admin AT ubik /tmp/math
> $ gcc-4 math.c -o math -ffast-math
> 
> admin AT ubik /tmp/math
> $ gcc-4 math.c -o math -ffast-math -O2
> 
> admin AT ubik /tmp/math
> $ gcc-4 math.c -o math -ffast-math -O3
> 
> admin AT ubik /tmp/math
> $

  Perhaps a few more details about what you're doing, a simple reproducible
testcase, what kind of command-lines you're using, etc. etc... might help.

    cheers,
      DaveK


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