[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 nomeata):

 > It might be a different matter with concat (replicate 100000000
 ['\001'..'z']).

 Eh, that’s of course the code I intended, thanks for noticing!

 ... unfortunately, not even that code gets faster:
 {{{
 $ python -m timeit -s 'import os' 'os.system("./IsSpace-before")'
 10 loops, best of 3: 4.9 sec per loop
 $ python -m timeit -s 'import os' 'os.system("./IsSpace-after")'
 10 loops, best of 3: 4.9 sec per loop
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10124#comment:19>
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