[GHC] #14068: Loopification using join points

[GHC]

#14068: Loopification using join points
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        Reporter:  nomeata           |                Owner:  nomeata
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:  JoinPoints
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #13966 #14067     |  Differential Rev(s):  Phab:D3811
  #14827                             |
       Wiki Page:                    |
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Comment (by simonpj):

 > If these were fixed we would get rid of some of the SpecConstr related
 regressions introduced by loopification – but still not all of them, I
 fear, and there will be more to be tracked down.

 But these are good things to track, more generally.  A program might be
 loopified by hand, so making loopification be non-regressive should
 benefit all programs.

 Another possible thing to try is to loopify after !SpecConstr; that is,
 treat loopificaiton as an optimisation whose main payoff is in the back
 end.  (One reason I am keen to move forward with loopificaion is because
 then we can remove some rather ad-hoc loopification code in the code
 generator.)   But I don't have a clear picture of where the wins from
 loopification come.  Maybe there are benefits earlier in the pipeline.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14068#comment:56>
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