[GHC] #8279: bad alignment in code gen yields substantial perf issue

[GHC]

#8279: bad alignment in code gen  yields substantial perf issue
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        Reporter:  carter            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.7
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #8082             |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by sgraf):

 I hit this today in `CSD` (kernel is basically a counting loop), with a
 delta of 12%. Supplying `-fllvm` swapped symptoms for me, still a delta of
 ~-8%. This was 1a0a971b76c0b717794af9af4e27dcb488924800 vs
 https://github.com/sgraf812/ghc/tree/25bba2b92b9bcdc090ae9418a0425ea0a829491e.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8279#comment:27>
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