[GHC] #9407: Program produces different output when compiled with -O

[GHC]

#9407: Program produces different output when compiled with -O
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              Reporter:  arotenberg  |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.3
            Resolution:              |         Keywords:
      Operating System:  Windows     |     Architecture:  x86_64 (amd64)
       Type of failure:  Incorrect   |       Difficulty:  Unknown
  result at runtime                  |       Blocked By:
             Test Case:              |  Related Tickets:
              Blocking:              |
Differential Revisions:              |
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Comment (by simonpj):

 OK so it seems likely to be something to do with 64-bit floating-point
 arithmetic.

 I wonder if it makes a difference whether you use the native code
 generator or LLVM?

 Does anyone feel able to investigate?  The program isn't very big, and has
 no dependencies other than `Prelude`.

 Simon

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9407#comment:6>
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