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Re: status of gcc4 -ffast-math
- From: Dave Korn <dave dot korn dot cygwin at googlemail dot com>
- To: cygwin at cygwin dot com
- Date: Thu, 05 Nov 2009 22:30:35 +0000
- Subject: Re: status of gcc4 -ffast-math
- References: <hcvglt$uj2$1@ger.gmane.org>
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@ubik /tmp/math
> $ gcc-4 math.c -o math
>
> admin@ubik /tmp/math
> $ gcc-4 math.c -o math -ffast-math
>
> admin@ubik /tmp/math
> $ gcc-4 math.c -o math -ffast-math -O2
>
> admin@ubik /tmp/math
> $ gcc-4 math.c -o math -ffast-math -O3
>
> admin@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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