[GHC] #10397: Compiler performance regression 7.6 -> 7.8 in elimCommonBlocks

[GHC]

#10397: Compiler performance regression 7.6 -> 7.8 in elimCommonBlocks
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        Reporter:  TobyGoodwin       |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.8.4
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |  performance
 Type of failure:  None/Unknown      |            Architecture:
      Blocked By:                    |  Unknown/Multiple
 Related Tickets:                    |               Test Case:  see ticket
                                     |                Blocking:
                                     |  Differential Revisions:
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Comment (by nomeata):

 Oh wow, just looked at the test case you provided. It’s really small:
 {{{
   19 Form.hs
   46 RegBig.hs
   52 RegSmall.hs
   17 Y.hs
  134 insgesamt
 }}
 but indeed takes very long. We should certainly improve the situation
 here.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10397#comment:3>
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