[GHC] #15091: Better occurrence analysis for join points

[GHC]

#15091: Better occurrence analysis for join points
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        Reporter:  simonpj           |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:  JoinPoints
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by sgraf):

 * cc: sgraf (added)


Comment:

 Sounds a lot like how the demand analyser always uses LetDown to handle
 join points. `Note [Demand analysis for join points]` might be relevant.

 I found that occurrence analysis, usage analysis and call arity (to an
 extent) are strongly related, as they all try to compute max cardinality
 info. So they should agree on how to handle join points.
 ticket:13479#comment:10 hints about this for Call Arity. Appearently,
 `Note [Call Arity and Join Points]` explains we currently don't do this
 because of complexity concerns, probably because Call Arity has no
 analogue of LetDown.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15091#comment:1>
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