[GHC] #10124: Simple case analyses generate too many branches

[GHC]

#10124: Simple case analyses generate too many branches
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        Reporter:  bgamari           |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.8.4
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:  #6135,            |  Differential Revisions:
  #9661,#10137                       |
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Comment (by rwbarton):

 This benchmark does quite a lot of allocation, unless that changes in HEAD
 (I tested with 7.10.1). It would be better for microbenchmarking purposes
 to avoid all the allocation.

 Anyways I would expect the original to be a bit faster for this particular
 microbenchmark, since the branches will all be predicted correctly and a
 predicted branch is basically free. It might be a different matter with
 `concat (replicate 100000000 ['\001'..'z'])`.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10124#comment:16>
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