[GHC] #15426: `elemIndex` and `findIndex` still can't fuse

[GHC]

#15426: `elemIndex` and `findIndex` still can't fuse
-------------------------------------+-------------------------------------
        Reporter:  kabuhr            |                Owner:  kabuhr
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.8.1
       Component:  libraries/base    |              Version:  8.4.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
                                     |  testsuite/tests/perf/should_run/T15426.hs
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |  https://phabricator.haskell.org/D5063
-------------------------------------+-------------------------------------

Comment (by simonpj):

 > The change resulted in a slight increase (3%) to memory usage for the
 cacheprof benchmark

 By "memory usage" do you mean "allocation"?  A 3% increase in allocation
 is very strange, and worth understanding better.  (I use `-ticky` for
 these kind of before-and-after comparisons.)

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15426#comment:7>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler