[GHC] #5814: LLVM 3.0 doesn't support llvm.memory.barrier

[GHC]

#5814: LLVM 3.0 doesn't support llvm.memory.barrier
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 Reporter:  bgamari           |          Owner:  dterei          
     Type:  bug               |         Status:  merge           
 Priority:  normal            |      Component:  Compiler (LLVM) 
  Version:  7.5               |       Keywords:                  
       Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
  Failure:  None/Unknown      |       Testcase:                  
Blockedby:                    |       Blocking:                  
  Related:                    |  
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Changes (by dterei):

  * status:  new => merge


Comment:

 OK pushed patch + some improvements. I changed the fence to use the
 strongest sync of seq_cst (sequentially consistent). I'm not sure if this
 is too much and perhaps your use of acq_rel (acquire+release) would be
 enough. Please check what actual machine code is generated by GHC and
 maybe talk to Simon M.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5814#comment:3>
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