[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, #9661      |  Differential Revisions:
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Comment (by simonpj):

 I'm all for doing both!

  * Try to avoid duplication in the first place (comment:6)
  * Recover sharing even if duplication happens, or the programmer wrote it
 (comment:10)

 Re comment:10, one could do it in Cmm, but I suspect it'd be better done
 in Core.  Could be a variant of `Note [Combine identical alternatives]` in
 `SimplUtils`.

 Over to you, Ben.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10124#comment:11>
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