[GHC] #8048: Register spilling produces ineffecient/highly contending code

[GHC]

#8048: Register spilling produces ineffecient/highly contending code
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        Reporter:  schyler           |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:  ⊥
       Component:  Compiler          |          Version:  7.6.3
      Resolution:                    |         Keywords:  register
Operating System:  Unknown/Multiple  |  allocator spill
 Type of failure:  Runtime           |     Architecture:  Unknown/Multiple
  performance bug                    |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Changes (by schyler):

 * component:  Compiler (NCG) => Compiler


Comment:

 Actually simon, I was able to reproduce this with LLVM also and carter can
 confirm. Interestingly, when we fiddled with some flags like -march=native
 and such, llvm seemed to bandaid it somehow by using mmx where the
 rotation happened properly.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8048#comment:11>
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