[GHC] #14816: Missed Called Arity opportunity?

[GHC]

#14816: Missed Called Arity opportunity?
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        Reporter:  dfeuer            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
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 nomeata):

 Sorry. I  commented here, but my comment seems to have disappeared…
 probably did not send it.

 > `insertModifying` uses its function argument at most once, so there is
 no possible benefit to this partial application.

 but does GHC know this (non-local) fact?
 What is the strictness signature of `RULES.$w$sinsertModifying`.

 Also, what is the Core directly after Call Arity? (`-ddump-call-arity`)?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14816#comment:1>
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