[vorbis] Re: [vorbis-dev] bug in glibc 2.1.2 and older

[Monty]

> On Sat, 24 Jun 2000, Monty wrote:
> 
> > I was wrong.  It seems that glibc 2.1.2 and older is still alive and well.
> 
> It's worse than that:  www.gnu.org still (at least as of a couple of days
> ago) points to 2.1.2 as being the latest and greatest.

My.

> > If replacing libc is not an option, all C modules should be built with
> > _D__NO_MATH_INLINES This will result in a performance sacrifice, but
> > will produce correct binaries.
> 
> Compiling with optimization level 1 (-O or -O1) also apparently works (at
> least it's worked for my linux-intel system) without the huge (~36%)
> performance hit.

Actually, if a change in optimization causes different FPU scheduling, it may 
*appear* that the bug is fixed, when in fact it's still a ticking bomb (or may 
go off elsewhere).

For example, one of the early frustrations in tracking this bug last year was 
that adding a printf to watch the results go wrong will suddently make it all 
work (because the printf forces a float store to memory, reducing load on the 
stack).

>  For distribution or serious testing, however, I'd play
> it safe for now and kill the inlines completely.

Most likely a good idea.  Greg Olszewski (Hey Greg!  Great to see you on the
list!  Where are you hanging out to do your remote hacking these days?) has
already submitted an autoconf patch to hack a check in for this.  We can also
always build binaries for distribution on a system with a known, good glibc
(like Debian Woody).

Monty

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