[GHC] #9246: GHC generates poor code for repeated uses of min/max

[GHC]

#9246: GHC generates poor code for repeated uses of min/max
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        Reporter:  arotenberg               |            Owner:
            Type:  bug                      |           Status:  new
        Priority:  normal                   |        Milestone:
       Component:  Compiler                 |          Version:  7.8.2
      Resolution:                           |         Keywords:
Operating System:  Windows                  |     Architecture:  x86_64
 Type of failure:  Runtime performance bug  |  (amd64)
       Test Case:                           |       Difficulty:  Unknown
        Blocking:                           |       Blocked By:
                                            |  Related Tickets:  #6135
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Comment (by simonpj):

 Indeed!  What Core would you ''like'' to see generates for examples like
 `UglyBranching`?

 The underlying difficulty is that the case-of-case transformation is
 utterly crucial for optimising Haskell programs, and it's hard to predict
 when it'll be unproductive, or even counter-productive.  I'd welcome
 ideas.

 case-of-case is described in "A transformation based optimiser for
 Haskell", and (in passing) in many other papers.

 Simon

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9246#comment:7>
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