Re: MacOs X Lion compiler and PARI

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

On Sat, Aug 06, 2011 at 09:15:01AM -0700, William Stein wrote:
> On Fri, Aug 5, 2011 at 5:30 AM, Bill Allombert
> <Bill.Allombert@math.u-bordeaux1.fr> wrote:
> > Hello PARI developers,
> >
> > I received reports that MacOs X Lion default compiler is unable to compile PARI
> > correctly. Precisely this version:
> >
> > GNU compiler version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)
> >
> > So far I got two kind of issues:
> > With --with-gmp, PARI build, but the resulting code is broken (see bug #1222)
> > With --without-gmp, PARI fails to build (see
> > <http://pari.math.u-bordeaux.fr/buildlogs/dac98dec-af1e-4e54-97ba-f001b69bf7a9>)
> >
> > Concerning, the first issue, I do not have access to such a system and in any
> > case I cannot fix Apple compiler, so I would appreciate if one of you Mac OS X
> > users would report the problem to Apple.

> To encourage porting efforts to Lion, I setup a computer with the
> latest OS and XCode 4.1 on it.

Thanks a lot, this has allowed to confirm that the problem 
is a compiler issue that cause the file 'src/kernel/none/gcdll.c'
(included in mp.c) to be miscompiled with -O1 and up.
The symptom is that
bezout(7,2) return [0, 1, 2] instead of [1, -3, 1].

> By the way, Mike Hansen was able to build the PARI that is in Sage
> (along with its dependency MPIR) on this machine and it works:

Did you use the default compiler ?
Did you use the default optimization level ?

Cheers,
Bill.