[GHC] #14295: tagToEnum# leads to some silly closures

[GHC]

#14295: tagToEnum# leads to some silly closures
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        Reporter:  dfeuer            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.4.1
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:  datacon-tags
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 dfeuer):

 Replying to [comment:6 simonpj]:
 > > Unsurprisingly, exactly the same thing is true for quotInt# and such.
 >
 > I don't understand.  Can you explain?

 {{{#!hs
 foo :: (Int -> a) -> Int# -> Int# -> a
 foo f x y = f (I# (quotInt# x y))
 }}}

 will suspend the division for fear of a zero denominator. We can fix that
 similarly by testing for 0 and forcing the division in the good branch.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14295#comment:7>
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