[GHC] #14372: CMM contains a bunch of tail-merging opportunities

[GHC]

#14372: CMM contains a bunch of tail-merging opportunities
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        Reporter:  heisenbug         |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:
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 nomeata):

 >  It would be nice to factor out the common tails, e.g. by branching to
 the first tail already emitted.

 Branches can be expensive, so this might not be a clear win. Have you
 measured the effect? (You can do that without modifying GHC: Just get your
 hands on the assembly file, make the changes you want to see, and
 compare.)

 The other idea, detecting blocks that are equal up-to a constant, sounds
 fun. But again, the question is: Is it worth it?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14372#comment:2>
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