[GHC] #9777: -msse flag could be handled better by the driver

[GHC]

#9777: -msse flag could be handled better by the driver
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              Reporter:  jstolarek   |            Owner:  dredozubov
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Driver      |          Version:  7.9
            Resolution:              |         Keywords:  newcomer
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Moderate (less
       Type of failure:  Other       |  than a day)
             Test Case:              |       Blocked By:
              Blocking:              |  Related Tickets:  #8404
Differential Revisions:  Phab:D504   |
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Comment (by jstolarek):

 > I agree on "multiple -msse flags" point. It's completely reasonable to
 choose last version if multiple flags were provided by user.

 What do you mean by "last version". "Latest SSE version" or "last version
 given on the command line"? I meant the former.

 As for tests, you can test that:
 1. all `msse` flags are listed by `--show-options` flag
 2. incorrect `-msse` flag is rejected (see
 https://phabricator.haskell.org/D503 for an example how to do that).

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9777#comment:9>
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