[GHC] #9345: Data.List.inits is extremely slow

[GHC]

#9345: Data.List.inits is extremely slow
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              Reporter:  dfeuer      |            Owner:
                  Type:  bug         |           Status:  patch
              Priority:  high        |        Milestone:  7.8.4
             Component:              |          Version:  7.8.3
  libraries/base                     |         Keywords:
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:              |       Difficulty:  Easy (less than 1
  Unknown/Multiple                   |  hour)
       Type of failure:  Runtime     |       Blocked By:
  performance bug                    |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by dfeuer):

 If someone is able to do benchmark comparisons for lists of various sizes,
 that would really be great; I'm not currently able to use Criterion on GHC
 7.9. It's possible that `initsQ` is better when the list is fairly small
 relative to the cache size and `initsT'` is better when it's large, in
 which case someone will have to make a judgement about which case is more
 important.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9345#comment:17>
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