[GHC] #7684: cgrun071 segfaults

[GHC]

#7684: cgrun071 segfaults
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        Reporter:  tibbe          |            Owner:
            Type:  bug            |           Status:  new
        Priority:  normal         |        Milestone:  7.8.1
       Component:  Compiler       |          Version:  7.7
      Resolution:                 |         Keywords:
Operating System:  MacOS X        |     Architecture:  x86_64 (amd64)
 Type of failure:  Runtime crash  |       Difficulty:  Unknown
       Test Case:  cgrun071       |       Blocked By:
        Blocking:                 |  Related Tickets:
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Comment (by rwbarton):

 (According to [http://gcc.gnu.org/ml/gcc/2013-01/msg00447.html this
 discussion with an editor of the System V x86_64 ABI], a callee must NOT
 assume that its arguments have been sign-/zero-extended to fill their
 registers.  So the gcc 4.2 `hs_popcnt8` is wrong, and the gcc 4.8
 `hs_popcnt8` is right.  However, pointing the finger at a widely-installed
 compiler is not very helpful when we could presumably fix the issue by
 doing the zero-extension in ghc instead.)

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7684#comment:30>
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