[vorbis] Serious GCC/EGCS 2.91 bug found (bites rc2)

[Dr.Joerg Bergmann]

Hi vorbis/ogg developers alltogether,

On Thu, 16 Aug 2001, Monty wrote:

> Hi folks,
> 
> The folks on RedHat who have been complaining of poor-quality encodes
> prompted us to track down the trouble, and it's a compiler bug.  We
> have the asm .s files to prove it :-)
> 
In summary, all the math in GCC seems not to be of high quality.
I have had many troubles compiling some kind of code (runs good
using Watcom C for DOS/Win32/OS2) for Linux. I have tested
three different Linux versions resp. compilers:
-Red Hat 6.1
-SuSE 7.0
-SuSE 7.2 shipped with gcc version 2.95.3!!!
All they have corrupted my code, even with optimization switched off!
The atanh function seems to be buggy. It gives correct results in
a stand-alone environment. But it behaves in some kind illegal,
it corruptes the whole program. By masking atanh by
#undef atanh
#define atanh(x) myatanh(x)
and setting up my own myatanh, the program runs good.

Because I think ogg/vorbis does extensive uses math functions, I
give this warning to you.

J"org Bergmann, Dresden, Germany
email at jbergmann.de

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