[GHC] #1473: isSpace is too slow

[GHC]

#1473: isSpace is too slow
-------------------------------------+-------------------------------------
              Reporter:  igloo       |            Owner:  ekmett
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:  7.10.1
             Component:  Core        |          Version:  6.6.1
  Libraries                          |         Keywords:
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:              |       Difficulty:  Unknown
  Unknown/Multiple                   |       Blocked By:
       Type of failure:              |  Related Tickets:
  None/Unknown                       |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------

Comment (by Austin Seipp <austin@…>):

 In [changeset:"31571270625a690410b794b7cfe48d866c084e74/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="31571270625a690410b794b7cfe48d866c084e74"
 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
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1473#comment:10>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler