[GHC] #9923: Offer copy-on-GC sliced arrays

[GHC]

#9923: Offer copy-on-GC sliced arrays
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        Reporter:  dfeuer            |                   Owner:  simonmar
            Type:  feature request   |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Runtime System    |                 Version:  7.11
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
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Comment (by svenpanne):

 Hmmm, I doubt that this would work: The proposal means that the garbage
 collector must allocate memory during collections, which is quite the
 opposite what it is supposed to do. Put another way: If somebody (SimonM?)
 thinks that this is possible, I would be very interested in the details.
 Even if this somehow works, there are several pathological cases like
 having lots of 999999-element slices of a 1000000-element array.

 Short-circuiting projection functions is OK (IIRC nhc did that first)
 because one doesn't have to allocate, but slicing is not really
 projecting.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9923#comment:1>
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