[GHC] #3924: Strictness analyser missing useful strictness

[GHC]

#3924: Strictness analyser missing useful strictness
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        Reporter:  simonpj           |            Owner:
            Type:  bug               |           Status:  new
        Priority:  low               |        Milestone:  7.6.2
       Component:  Compiler          |          Version:  6.12.1
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by nomeata):

 This looks like it can be solved by the new callartiy analysis. It does
 now, because

   * all the functions are top-level functions, and callartiy analysis now
 also looks at top-level functions, and
   * they are mutually recursive, which the callarity analysis does handle
 now.

 Now we get these signatures:
 {{{
 $wf3 :: Int# -> Int# -> Int# -> Int#
 $wf4 :: Int# -> Int# -> Int# -> Int# -> Int#
 }}}
 (and f2 has disappeared, by inlining I supposed).

 Code is currently validating and will hit master soon after.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3924#comment:10>
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