[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:  (none)
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:  7.10.2
       Component:  Compiler          |              Version:  7.8.4
      Resolution:  fixed             |             Keywords:  performance
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:  see ticket
      Blocked By:                    |             Blocking:
 Related Tickets:  #14226            |  Differential Rev(s):  Phab:D892
       Wiki Page:                    |  Phab:D896
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Comment (by bgamari):

 I should correct my statement from comment:39 as I misunderstood the
 intent of the patch from comment:28:

 The commit does not change the behavior of CBE; rather, it only adjusts
 the hash function used for "rough" comparison to more closely reflect the
 equality relation used later.

 However, I would argue that our CBE is still significantly less aggressive
 than it should be. Let's continue this discussion on #14226.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10397#comment:41>
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