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[perl #127999] Slowdown in split + list assign

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From:
Todd Rinaldo via RT
Date:
September 12, 2016 23:38
Subject:
[perl #127999] Slowdown in split + list assign
Message ID:
rt-4.0.24-25366-1473723507-1775.127999-15-0@perl.org
On Mon May 02 01:22:23 2016, davem wrote:
> On Sun, May 01, 2016 at 06:18:48PM -0400, Ricardo Signes wrote:
> > * Father Chrysostomos via RT <perlbug-followup@perl.org> [2016-05-
> > 01T08:53:20]
> > > Attached is a patch, which is also smoking on the smoke-me/127999
> > > branch.
> >
> > I will apply this patch and cut an RC4 *immediately* if I can get two
> > other
> > committers to give it a +1.
> 
> a -1 from me :-(.
> 
> With the patch, the assign op still gets the OPpASSIGN_COMMON_AGG flag
> set:
> 
> $ ./perl -Ilib -MO=Concise,-exec -e'my @a; @a = ((split //, $s), "-")'
> | grep aassign
> -e syntax OK
> d  <2> aassign[t3] vKS/COM_AGG
> 
> so it still gets the slowdown.
> 
> I think we should leave it as-is for 5.24, then re-address the whole
> OA_DANGEROUS issue for 5.26.
> 
> Bear in mind that this only affects the specific case of a split *plus
> other elements* being assigned to an array. These won't be slowed
> down:
> 
> @a = split(/.../, $s);
> foo(split(/.../, $s), '-');
> 
> I think trying to tweak it at this late stage it just likely to
> introduce new common-assign bugs.


Bump.  Is this still on the list to fix for the current blead?

---
via perlbug:  queue: perl5 status: open
https://rt.perl.org/Ticket/Display.html?id=127999

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