[GHC] #8072: Optimizations change result of div for Word

[GHC]

#8072: Optimizations change result of div for Word
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        Reporter:  Khudyakov         |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  Compiler          |          Version:  7.6.3
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  x86
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:  3676
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Comment (by Khudyakov):

 I don't think #3676 is related. It's because of incorrectness of
 realToFrac. Funky values like NaN and ±∞ are not representable as
 rationals so realToFrac converts Float to Double incorrectly but
 specialized version does it right so this difference arise. In this bug we
 are dealing only with integer arithmetics.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8072#comment:5>
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