[GHC] #12469: Memory fence on writes to MutVar/Array missing on ARM

[GHC]

#12469: Memory fence on writes to MutVar/Array missing on ARM
-------------------------------------+-------------------------------------
        Reporter:  rrnewton          |                Owner:  trommler
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:  8.0.2
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:  memory model
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect result  |  Unknown/Multiple
  at runtime                         |            Test Case:
      Blocked By:                    |             Blocking:  12537
 Related Tickets:                    |  Differential Rev(s):  Phab:D2495
       Wiki Page:                    |  Phab:D2525
-------------------------------------+-------------------------------------

Comment (by trommler):

 Another Stackage Nightly build with ghc 8.0.1 patched with Phab:D2495 and
 Phab:D2525:
 {{{
 ghc: internal error: MUT_VAR_CLEAN object entered!
     (GHC version 8.0.1 for powerpc64le_unknown_linux)
     Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
 }}}

 This error seems to be even more difficult to trigger on Open Build
 Service. I have not seen this locally on my PowerMac (running powerpc64
 Linux).

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12469#comment:18>
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