[GHC] #8834: 64-bit windows cabal.exe segfaults in GC

[GHC]

#8834: 64-bit windows cabal.exe segfaults in GC
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        Reporter:  awson          |            Owner:
            Type:  bug            |           Status:  patch
        Priority:  highest        |        Milestone:  7.8.1
       Component:  Compiler       |          Version:  7.8.1-rc2
      Resolution:                 |         Keywords:
Operating System:  Windows        |     Architecture:  x86_64 (amd64)
 Type of failure:  Runtime crash  |       Difficulty:  Unknown
       Test Case:                 |       Blocked By:
        Blocking:                 |  Related Tickets:
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Comment (by awson):

 Yes, they are in RTS. More precise location is rts/sm/Evac.c line 390.

 Also I think this bug is triggered near foreign `memchr` call in function
 `elemIndex` from `Data.ByteString` module in `bytestring` package, which
 is inlined down to `lines` function from `Data.ByteString.Char8`.

 Also I checked this bug is not triggered if relevant modules from
 `bytestring` package are compiled with `-O` flag instead of `-O2`, hence
 this bug could be more ubiquitous if more applications code was compiled
 with `-O2`, perhaps.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8834#comment:23>
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