[GHC] #16039: 'GHC.Magic.noinline <var>' should not float out

[GHC]

#16039: 'GHC.Magic.noinline <var>' should not float out
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        Reporter:  heisenbug         |                Owner:  heisenbug
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.10.1
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:  FloatOut
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #15155            |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 > `exprIsCheapX` helped a lot

 What does that mean?  How did it help?

 Rather than doing this deep pattern matching during `exprIsCheapX` (which
 will happen repeatedly in an `App`-chain), I think it might be nicer (more
 efficient) to accumulate a list of (value) arguments instead of the `n`
 argument to `go`.

 >  Check out exprIsBig too.

 Maybe.  But concentrate on the places where we know it makes a difference.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16039#comment:10>
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