[GHC] #5075: CPR optimisation for sum types if only one constructor is used

[GHC]

#5075: CPR optimisation for sum types if only one constructor is used
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    Reporter:  batterseapower    |       Owner:  simonpj         
        Type:  feature request   |      Status:  patch           
    Priority:  normal            |   Milestone:  7.6.2           
   Component:  Compiler          |     Version:  7.0.3           
    Keywords:                    |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown    
  Difficulty:  Unknown           |    Testcase:                  
   Blockedby:                    |    Blocking:                  
     Related:                    |  
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Comment(by simonpj):

 Still to come: the sum-CPR stuff is switched off for '''nested'''
 functions because it turns some let-no-escape functions into non-let-no-
 escape ones, which increases allocation. I'm hopeful that Nick F's work on
 late-lambda-lifting may solve this, in which case we can switch it on more
 vigorously.  Hence leaving open for now.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5075#comment:9>
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