[GHC] #10677: slightly silly assembly for testing whether a Word# is 0##

[GHC]

#10677: slightly silly assembly for testing whether a Word# is 0##
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        Reporter:  rwbarton          |                   Owner:
            Type:  bug               |                  Status:  patch
        Priority:  low               |               Milestone:
       Component:  Compiler          |                 Version:  7.11
  (CodeGen)                          |
      Resolution:                    |                Keywords:  newcomer
Operating System:  Unknown/Multiple  |            Architecture:  x86_64
 Type of failure:  Runtime           |  (amd64)
  performance bug                    |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:  #10750            |  Differential Revisions:  Phab:D1137
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Comment (by Joachim Breitner <mail@…>):

 In [changeset:"92f35cd9829db7555397aa3dc8cd243d17694fee/ghc"
 92f35cd9/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="92f35cd9829db7555397aa3dc8cd243d17694fee"
 cmmCreateSwitchPlan: Handle singletons up-front

 and make sure these are implemented with an equality check, which is a
 shorter instruction. This was suggested by rwbarton in #10677.

 Differential Revision: https://phabricator.haskell.org/D1137
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10677#comment:7>
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