[GHC] #11095: -O0 -g slows GHC down on list literals (compared to -O0 without -g)

[GHC]

#11095: -O0 -g slows GHC down on list literals (compared to -O0 without -g)
-------------------------------------+-------------------------------------
        Reporter:  slyfox            |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  phab:D3001
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"532c6ade49e9e8e7e98c35451058ba7e4ee7bb9c/ghc" 532c6ad/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="532c6ade49e9e8e7e98c35451058ba7e4ee7bb9c"
 Make tickishContains faster

 This just reorders some inequality checks to make the common case
 cheaper.

 The results are quite dramatic for #11095, but that's probably because
 something else is causing it to do too much work.

 Before (full https://phabricator.haskell.org/P136):
 ```
   13,589,495,832 bytes allocated in the heap
 ```

 After (full https://phabricator.haskell.org/P137):
 ```
    7,885,575,872 bytes allocated in the heap
 ```

 This is with `BuildFlavour = devel2`, so take it with a
 a grain of salt.

 For reference, with no `-g` I get:
 ```
 155,703,112 bytes allocated in the heap
 ```
 so we're still quite a way off.

 Test Plan:
 harbormaster
 I still have to test locally

 Reviewers: austin, bgamari

 Subscribers: thomie, simonmar

 Differential Revision: https://phabricator.haskell.org/D3001

 GHC Trac Issues: #11095
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11095#comment:5>
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