[GHC] #9279: Local wrapper function remains in final program; result = extra closure allocation

[GHC]

#9279: Local wrapper function remains in final program; result = extra closure
allocation
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        Reporter:  simonmar          |                Owner:  simonpj
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.8.2
      Resolution:                    |             Keywords:  LateLamLift
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by sgraf):

 If I apply this diff

 {{{
 diff --git a/compiler/basicTypes/Literal.hs
 b/compiler/basicTypes/Literal.hs
 index 21f4a92290..4444f69c7b 100644
 --- a/compiler/basicTypes/Literal.hs
 +++ b/compiler/basicTypes/Literal.hs
 @@ -618,6 +618,8 @@ absentLiteralOf tc = lookupUFM absent_lits (tyConName
 tc)

  absent_lits :: UniqFM Literal
  absent_lits = listToUFM [ (addrPrimTyConKey,    MachNullAddr)
 +                        , (mutVarPrimTyConKey,  MachNullAddr)
 +                        , (tVarPrimTyConKey,    MachNullAddr)
                          , (charPrimTyConKey,    MachChar 'x')
                          , (intPrimTyConKey,     mkMachIntUnchecked 0)
                          , (int64PrimTyConKey,   mkMachInt64Unchecked 0)
 }}}

 Everything WWs properly and the troubling binding `$wlvl` gets lifted to
 top-level. Given that this might bite somewhere else, should we maybe
 generalise `absentLiteralOf` by returning `MachNullAddr` whenever it gets
 a boxed type?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9279#comment:14>
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