[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:  (none)
            Type:  bug               |               Status:  new
        Priority:  highest           |            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 bgamari):

 > uh, I should specify that I mean the configure test doesn't.

 What precisely is the problem?

 As far as I can tell Clang has supported both `__atomic_*` and `__sync_*
 builtins at least as far back as LLVM 3.4. I'm fairly certain that
 `__sync_*` are supported by `icc` as I have read that this builtins were
 stolen by `gcc` from `icc`.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14244#comment:12>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler