[GHC] #9534: IEEE Standard 754 for Binary Floating-Point Arithmetic by Prof. W. Kahan, UCB

[GHC]

#9534: IEEE Standard 754 for Binary Floating-Point Arithmetic by Prof. W. Kahan,
UCB
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              Reporter:  jrp         |            Owner:
                  Type:  task        |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Test Suite  |          Version:  7.8.3
            Resolution:              |         Keywords:  IEEE754
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Moderate (less
       Type of failure:  Incorrect   |  than a day)
  result at runtime                  |       Blocked By:
             Test Case:              |  Related Tickets:
              Blocking:              |
Differential Revisions:              |
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Comment (by carter):

 still haven't worked through this fully, BUT  min/max for float/double in
 ghc haskell are certainly defined differently from the the 2008 IEEE
 floating point standard (nb: the definition of min/max in the ieee
 standard was only added to the 2008 version and merely codified certain
 unusual idioms/patterns from the C language useage of min/max on Nans).

 In contrast, GHC Haskell's compare is defined wrt a quiet (not signalling)
 comparison on input arguments (which mean that when min max have a nan in
 either arg, we just take the second arg currently.). Of course, this is a
 bit unsatisfactory if only  because it makes min/max not commutative
 operations in the presence of NaN. (though in some respects I view the
 current IEEE definition that just codifies the C version as more
 problematical still!)

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9534#comment:3>
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