[GHC] #14619: Output value of program changes upon compiling with -O optimizations

[GHC]

#14619: Output value of program changes upon compiling with -O optimizations
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        Reporter:  sheaf             |                Owner:  (none)
            Type:  bug               |               Status:  infoneeded
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:  x86_64
 Type of failure:  Incorrect result  |  (amd64)
  at runtime                         |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by sheaf):

 I'm not doing anything specific at all, just plain vs -O2 as you seem to
 be doing.


 {{{
 > ghc bug.hs
 [1 of 1] Compiling Main             ( bug.hs, bug.o )
 Linking bug.exe ...

 > bug
 Just ((0.0,0.0,100.0),1.0)
 Just ((0.0,0.0,100.0),1.0)

 > ghc bug.hs -O2 -fforce-recomp
 [1 of 1] Compiling Main             ( bug.hs, bug.o )
 Linking bug.exe ...

 > bug
 Just ((0.0,0.0,0.0),0.0)
 Just ((0.0,0.0,100.0),1.0)
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14619#comment:4>
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