[GHC] #15573: Make bindings with multiple occurrences a join point instead of duplicating code during inlining.

[GHC]

#15573: Make bindings with multiple occurrences a join point instead of duplicating
code during inlining.
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        Reporter:  AndreasK          |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.4.3
      Resolution:                    |             Keywords:  JoinPoints
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 This relates to #15560: in the current ticket you are proposing the to use
 float-in (the opposite of float-out) to make `cseAlts_s1dD` a local
 binging again.

 I'd prefer instead to make the top-level version (in the Description) more
 efficient so that it's just as efficient as the join-point version.

 One reason I want to do that is because it improves inlining
 opportunities, by making the function (`fmerge` in this case) smaller.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15573#comment:1>
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