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Re: -Duse64bitint pros and cons

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From:
Michael G Schwern
Date:
April 17, 2010 04:32
Subject:
Re: -Duse64bitint pros and cons
Message ID:
4BC99C3D.6070905@pobox.com
Niko Tyni wrote:
> we have a long-standing request [1] to set -Duse64bitint on the 32 bit
> Debian architectures. Now that there's going to be an ABI change with
> 5.12.0 this would be possible, but I'm wondering if it's the right thing
> to do.
> 
> I'd be glad to hear any opinions and recommendations on this. I understand
> the downside is that the memory consumption of every IV slot doubles.
> Is this bad enough that use64bitint should not be enabled on a "general
> purpose" /usr/bin/perl ?

+1

And don't forget -Duselongdouble.

Debugging numeric inaccuracy is a PITA.  Anything which helps maintain Perl's 
illusion that numbers are numbers, like we learned in math class, and not 
streams of bits, is good.

I can't speak much to memory usage impact, except to say that its cheaper than 
water.  One can look at it this way: Perl's arbitrary precision math libraries 
are more memory and processor hungry than 64 bit integers.  Anything you can 
do to push off having to switch to arbitrary precision numbers saves you memory.


-- 
52. Not allowed to yell "Take that Cobra" at the rifle range.
     -- The 213 Things Skippy Is No Longer Allowed To Do In The U.S. Army
            http://skippyslist.com/list/

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