[GHC] #13379: Space leak / quadratic behavior when inlining

[GHC]

#13379: Space leak / quadratic behavior when inlining
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        Reporter:  jberryman         |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:  Inlining
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #13586            |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"29d88ee173bc9b04245a33d5268dda032f5dc331/ghc"
 29d88ee1/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="29d88ee173bc9b04245a33d5268dda032f5dc331"
 Be a bit more eager to inline in a strict context

 If we see f (g x), and f is strict, we want to be a bit more eager to
 inline g, because it may well expose an eval (on x perhaps) that can
 be eliminated or shared.

 I saw this in nofib boyer2, function RewriteFuns.onewayunify1.  It
 showed up as a consequence of the preceding patch that makes the
 simplifier do less work (Trac #13379).  We had

    f d (g x)

 where f was a class-op. Previously we simplified both d and
 (g x) with a RuleArgCtxt (making g a bit more eager to inline).
 But now we simplify only d that way, then fire the rule, and
 only then simplify (g x).  Firing the rule produces a strict
 funciion, so we want to make a strict function encourage
 inlining a bit.
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13379#comment:18>
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