[GHC] #5683: bug in signum function

[GHC]

#5683: bug in signum function
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        Reporter:  tristes_tigres    |                Owner:
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:  7.6.1
       Component:  Prelude           |              Version:  7.0.3
      Resolution:  fixed             |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Other             |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by thomie):

 This was fixed in commit d9a20573f473cc7389004470999b8a318aa6b3f2:
 {{{
 Author: Alexander Berntsen <alexander at plaimi.net>
 Date:   Mon Aug 18 21:43:33 2014 -0500

     Make Prelude.signum handle -0.0 correctly (#7858)

     Summary:
     Make the `Float` and `Double` implementations of `signum` handle -0.0
     correctly per IEEE-754.

     This, together with "Make Prelude.abs handle -0.0 correctly (#7858)",
     fixes Trac #7858.

     Depends on D145

     Signed-off-by: Alexander Berntsen <alexander at plaimi.net>

     Test Plan:
     signum of (-0.0) should be (-0.0) not 0.0.

     Test program:

       main =
         putStrLn $ p ++ " " ++ n
         where
           f = show . signum
           p = f (-0.0 :: Double)
         n = f (0.0 :: Double)

     Reviewers: ekmett, hvr, rwbarton, austin

     Reviewed By: austin

     Subscribers: phaskell, simonmar, relrod, ezyang, carter

     Differential Revision: https://phabricator.haskell.org/D148

     GHC Trac Issues: #7858
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5683#comment:14>
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