[GHC] #13570: CoreFVs patch makes n-body slower

[GHC]

#13570: CoreFVs patch makes n-body slower
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        Reporter:  simonpj           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Description changed by dfeuer:

@@ -1,1 +1,1 @@
- This commit
+ The commit 751996e90a964026a3f86853338f10c82db6b610

New description:

 The commit 751996e90a964026a3f86853338f10c82db6b610
 {{{
 commit 751996e90a964026a3f86853338f10c82db6b610
 Author: Simon Peyton Jones <simonpj at microsoft.com>
 Date:   Fri Apr 7 17:10:07 2017 +0100

     Kill off complications in CoreFVs
 }}}
 makes `n-body` in nofib go 25% slower.  See
 [https://perf.haskell.org/ghc/#revision/751996e90a964026a3f86853338f10c82db6b610
 perf results page].

 Investigate.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13570#comment:1>
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