[GHC] #13025: Type family reduction irregularity (change from 7.10.3 to 8.0.1)

[GHC]

#13025: Type family reduction irregularity (change from 7.10.3 to 8.0.1)
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        Reporter:  acowley           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:  TypeFamilies
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by RyanGlScott):

 acowley, you mentioned that there was a "2x slowdown in the benchmark
 available in the `vinyl` repository". But I see
 [https://github.com/VinylRecords/Vinyl/blob/7f436533ba0680434053629df1f844fdb58cb4fe/vinyl.cabal#L37-L51
 two benchmarks]. Which benchmark suffered the slowdown? I'd like to verify
 the change in runtime speed before and after commit
 1722fa106e10e63160bb2322e2ccb830fd5b9ab3.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13025#comment:6>
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