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

[GHC]

#12469: Memory fence on writes to MutVar/Array missing on ARM
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        Reporter:  rrnewton          |                Owner:
            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
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"2cb8cc26df6af431d30b6964710ea2d859ca2bcd/ghc" 2cb8cc2/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="2cb8cc26df6af431d30b6964710ea2d859ca2bcd"
 StgCmmPrim: Add missing write barrier.

 On architectures with weak memory consistency a write barrier
 is needed before the write to the pointer array.

 Fixes #12469

 Test Plan: rebuilt Stackage nightly twice on powerpc64le

 Reviewers: hvr, rrnewton, erikd, austin, simonmar, bgamari

 Reviewed By: erikd, bgamari

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D2525

 GHC Trac Issues: #12469
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12469#comment:32>
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