[GHC] #7883: enable GHC LLVM backend to use LLVM provided CAS / Atomicity primitives?

[GHC]

#7883: enable GHC LLVM backend to use LLVM provided CAS / Atomicity primitives?
-------------------------------------+-------------------------------------
        Reporter:  carter            |                Owner:  carter
            Type:  task              |               Status:  patch
        Priority:  normal            |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.9
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D1282
-------------------------------------+-------------------------------------

Comment (by Ben Gamari <ben@…>):

 In [changeset:"bd41eb2ad9507d3f408e25c8dece61f389f11a2a/ghc"
 bd41eb2a/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="bd41eb2ad9507d3f408e25c8dece61f389f11a2a"
 LLVM: Implement atomic operations in terms of LLVM primitives

 This fixes Trac #7883.

 This adds proper support for,
   * `MO_AtomicRMW`
   * `MO_AtomicWrite`
   * `MO_CmpXChg`

 Test Plan: Validate

 Reviewers: rrnewton, austin

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D1282

 GHC Trac Issues: #7883
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7883#comment:25>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler