[GHC] #14242: Ticks and join points don't play well

[GHC]

#14242: Ticks and join points don't play well
-------------------------------------+-------------------------------------
           Reporter:  bgamari        |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.2.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 Currently the presence of ticks appear to inhibit our ability to discover
 join points as described by this comment in `OccurAnal.occAnal`,
 {{{#!hs
     usage_lam = markAllNonTailCalled (markAllInsideLam usage)
                   -- TODO There may be ways to make ticks and join points
 play
                   -- nicer together, but right now there are problems:
                   --   let j x = ... in tick<t> (j 1)
                   -- Making j a join point may cause the simplifier to
 drop t
                   -- (if the tick is put into the continuation). So we
 don't
                   -- count j 1 as a tail call.
 }}}

 This causes spurious warnings when compiling with a `DEBUG` compiler and
 `-g` or profiling enabled.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14242>
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