[GHC] #14152: Float exit paths out of recursive functions

[GHC]

#14152: Float exit paths out of recursive functions
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        Reporter:  nomeata           |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:  JoinPoints
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #14137 #10918     |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 > Are you saying that it should be made False?

 Ah... no, for functions `int_cxt` is true if it is applied.

 Perhaps for join-points `preInlineUnconditionally` should never be True if
 `in_lam` is true.  That validates what we are trying here.

 > But there is an exception to that: Inside a recursive join point we do
 set occ_in_lam.

 Yes: `occ_in_lam` is true for a join point precisely when that join point
 is the exit of a recursive loop!  That's just what we want.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14152#comment:11>
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