[GHC] #9661: Branchless ==# is compiled to branchy code

[GHC]

#9661: Branchless ==# is compiled to branchy code
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        Reporter:  dfeuer            |                   Owner:  bgamari
            Type:  feature request   |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 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:  D854
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Comment (by bgamari):

 Replying to [comment:21 rwbarton]:
 > Did anyone ever come up with actual benchmarks that show a potential
 performance improvement from non-branching code? I must say I'm still
 rather skeptical of this whole project.

 You raise some fair points and perhaps Joachim's findings suggest that it
 it's not worth bending over backwards to accommodate branch-free code.
 Looking further into the performance implications of these branches is
 high on my to-do list.

 Regardless, there may be value in allowing rules to examine the
 application context even beyond this particular optimization (although at
 the risk of making RULEs a bit less predictable than they are currently).

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9661#comment:22>
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