[GHC] #9326: Minor change to list comprehension structure leads to poor performance

[GHC]

#9326: Minor change to list comprehension structure leads to poor performance
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              Reporter:  dfeuer      |             Owner:
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Compiler    |           Version:  7.8.3
            Resolution:              |          Keywords:
Differential Revisions:              |  Operating System:  Unknown/Multiple
          Architecture:              |   Type of failure:  Runtime
  Unknown/Multiple                   |  performance bug
            Difficulty:  Unknown     |         Test Case:
            Blocked By:              |          Blocking:
       Related Tickets:              |
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Changes (by slyfox):

 * cc: slyfox (added)


Comment:

 In 'comdspeed' one more rule did fire (to specialze .find on Ints):
 {{{
 "SPEC find [(Int, Int)]" [ALWAYS]
     forall @ a3_a2Tz $dOrd_s2U0. find $dOrd_s2U0 = $sfind
 }}}.

 It's seen in core comparison when use '''-ddump-simp -dsuppress-all'''.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9326#comment:3>
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