[GHC] #14244: ghc-prim: hs_atomicread* and hs_atomicwrite* missing barriers

[GHC]

#14244: ghc-prim: hs_atomicread* and hs_atomicwrite* missing barriers
-------------------------------------+-------------------------------------
        Reporter:  trommler          |                Owner:  trommler
            Type:  bug               |               Status:  patch
        Priority:  high              |            Milestone:  8.4.1
       Component:  Prelude           |              Version:  8.2.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect result  |  Unknown/Multiple
  at runtime                         |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #12537            |  Differential Rev(s):  Phab:D4009
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by Ben Gamari <ben@…>):

 In [changeset:"bd765f4b1332b3d2a7908de3f9ff1d50da0e0b1d/ghc" bd765f4/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="bd765f4b1332b3d2a7908de3f9ff1d50da0e0b1d"
 Fix atomicread/write operations

 In `libraries/ghc-prim/cbits/atomic.c` no barriers were issued for
 atomic read and write operations. Starting with gcc 4.7 compiler
 intrinsics are offered. The atomic intrinisics are also available in
 clang. Use these to implement `hs_atomicread*` and `hs_atomicwrite`.

 Test Plan: validate on OSX and Windows

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

 Reviewed By: bgamari

 Subscribers: dfeuer, rwbarton, thomie

 GHC Trac Issues: #14244

 Differential Revision: https://phabricator.haskell.org/D4009
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14244#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler