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	for caml-list@inria.fr; Mon, 07 Nov 2016 15:48:43 +0000
Date: Mon, 7 Nov 2016 15:48:43 +0000
From: "Richard W.M. Jones" <rich@annexia.org>
To: caml-list@inria.fr
Message-ID: <20161107154843.GH27249@annexia.org>
References: <20161107132201.GG27249@annexia.org>
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User-Agent: Mutt/1.5.23 (2014-03-12)
Subject: Re: [Caml-list] Zarith problems on ppc64le

On Mon, Nov 07, 2016 at 01:22:01PM +0000, Richard W.M. Jones wrote:
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1392247
> 
> Zarith fails tests on OCaml 4.04.0 + ppc64le with some fairly gross
> errors, eg:
> 
>  of_float -1.
> - = -1
> + = 0
> 
> (It passes fine on OCaml 4.04.0 + ppc64)
> 
> The implementation of Zarith is quite complex and I've so far failed
> to understand what's going on.

FWIW this seems like it is invoking undefined behaviour in C.  See
my analysis here:

https://bugzilla.redhat.com/show_bug.cgi?id=1392247#c3

Rich.