[GHC] #10788: performance regression involving minimum

[GHC]

#10788: performance regression involving minimum
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        Reporter:  rwbarton          |                   Owner:  ekmett
            Type:  bug               |                  Status:  closed
        Priority:  normal            |               Milestone:
       Component:  Core Libraries    |                 Version:  7.10.1
      Resolution:  fixed             |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by Joachim Breitner <mail@…>):

 In [changeset:"c6b82e99f41e03d4b101b3a32312defad711f56a/ghc"
 c6b82e99/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="c6b82e99f41e03d4b101b3a32312defad711f56a"
 Further simplify the story around minimum/maximum

 After I have found out that I should look at -ddump-prep and not
 -ddump-core, I noticed that these days, GHC is perfectly capeable of
 turning (the equivalent) of foldl to (the equivalent) of foldl' if the
 operation in question is strict. So instead of using rewrite rules to
 rewrite maximum to a strictMaximum for certain types, we simply use
 SPECIALIZE.

 This also marks maximum/minimum as INLINEABLE, so that client code can
 get similar specializations, hopefully even automatically. And inded,
 minimum applied to [Double] produces good code (although due to
 inlineing, not due to specialization, it seems).

 I checked (by looking at the core) that this still fixes #10788.

 Differential revision: https://phabricator.haskell.org/D1229
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10788#comment:14>
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