[GHC] #9638: Speed up Data.Char.isDigit

[GHC]

#9638: Speed up Data.Char.isDigit
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        Reporter:  dfeuer            |                   Owner:  ekmett
            Type:  feature request   |                  Status:  new
        Priority:  normal            |               Milestone:  7.12.1
       Component:  Core Libraries    |                 Version:  7.9
      Resolution:                    |                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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Changes (by thomie):

 * cc: core-libraries-committee@… (added)


Comment:

 dfeuer, is 31571270625a690410b794b7cfe48d866c084e74/ghc sufficient to
 close this ticket or is there more to be done here?

 {{{
 Author: David Feuer <>
 Date:   Tue Oct 21 15:01:14 2014 -0500

     Improve isDigit, isSpace, etc.

     Summary:
     Make things less branchy; use unsigned comparisons for range checking.
     Eliminate non-spaces more quickly in common cases in isSpace.

     Reviewers: ekmett, carter, austin

     Reviewed By: austin

     Subscribers: thomie, carter, ezyang, simonmar

     Differential Revision: https://phabricator.haskell.org/D340

     GHC Trac Issues: #1473
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9638#comment:10>
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