Re: perl: 64-bit integers and long doubles
On Tue, May 04, 2010 at 05:29:03PM +0200, Florian Weimer wrote:
> * Niko Tyni:
>
> > The benefits are obviously improved numeric range and precision. The
> > downside is presumably increased memory usage. I have no measurement
> > data on this; suggestions on suitable tests would be welcome.
>
> I have run into several incompatibilities between i386 and amd64 due
> to different Perl integer sizes, so I'm definitely in favor of 64-bit
> integers.
>
> I'm not sure if long doubles are a win. The rest of the world runs on
> 64 bit floating point numbers, so this would introduce additional
> incompatibilities.
I wasn't initially going for long doubles, but several upstream
developers recommended that they be enabled together.
http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2010-04/msg00773.html
http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2010-04/msg00895.html
Given that we've already run into a dozen or so incompatibilities
with just the CPAN modules, -Duselongdouble seems to be a pretty
rare thing to do. I'm inclined to revert this setting.
On Wed, May 05, 2010 at 01:50:30PM +1000, Brendan O'Dea wrote:
> On 4 May 2010 22:54, Niko Tyni <ntyni@debian.org> wrote:
> > It would be possible to choose these settings separately for each architecture.
> > Should I exclude the 'smaller' architectures (armel, mips*?)
>
> You could ask debian-arm@lists.debian.org and the other ports lists,
> but it seems reasonable to include 64bit support only on those
> architectures where there is native 64 bit support in the chipset.
Good point. Can anybody list our "pure" 32-bit architectures off-hand
or suggest a simple test? Checking the instruction set for each one
is a bit on the laborous side...
Ideally, I'd like to have a concrete plan to send to the ports lists
and just ask for any objections.
--
Niko Tyni ntyni@debian.org
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