[GHC] #15249: Add support for cmpeq and cmpgt MMX intrinsics

[GHC]

#15249: Add support for cmpeq and cmpgt MMX intrinsics
-------------------------------------+-------------------------------------
        Reporter:  newhoggy          |                Owner:  newhoggy
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:  8.8.1
       Component:  Compiler          |              Version:  8.4.3
      Resolution:                    |             Keywords:  primops
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by newhoggy):

 To implement this in pure haskell, I would need equivalent primops for the
 following CPU intrinsics:

 {{{
 _mm256_set1_epi8
 _mm256_cmpeq_epi8
 _mm256_movemask_epi8
 _mm256_cmpeq_epi8
 _mm256_movemask_epi8
 _mm256_maskload_epi64
 _mm256_maskstore_epi64
 }}}

 See:
 https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=vpmaskmovq&expand=765,767,802,5241,3295,3296,3297

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15249#comment:6>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler