[GHC] #8922: GHC unnecessarily sign/zero-extends C call arguments

[GHC]

#8922: GHC unnecessarily sign/zero-extends C call arguments
-------------------------------------+----------------------------------
        Reporter:  simonmar          |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:  7.10.1
       Component:  Compiler (NCG)    |          Version:  7.6.3
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  x86_64 (amd64)
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:  #7684
-------------------------------------+----------------------------------

Comment (by simonmar):

 My reading of it was that extending in the caller is not strictly
 necessary but is done as an optimisation to avoid partial register stalls.
 Maybe that means we ought to be doing it too - that's not clear to me.
 I'm sure it's not *always* an optimisation.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8922#comment:2>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler