[GHC] #13426: compile-time memory-usage regression for DynFlags between GHC 8.0 and GHC 8.2

[GHC]

#13426: compile-time memory-usage regression for DynFlags between GHC 8.0 and GHC
8.2
-------------------------------------+-------------------------------------
        Reporter:  hvr               |                Owner:  rwbarton
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.1
      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:D3399,
       Wiki Page:                    |  Phab:D3400
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"e13419c5562ed0aa587516255d1dbb48a8165457/ghc"
 e13419c5/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="e13419c5562ed0aa587516255d1dbb48a8165457"
 Fix space leaks in simplifier (#13426)

 The Join points commit (8d5cf8bf) introduced a space leak
 somewhere in the simplifier. The extra strictness added in this commit
 fixes the leak. Unfortunately I don't really understand the details.

 Unfortunately, the extra strictness appears to result in more overall
 allocations in some cases, even while the peak heap size decreases in
 others.

 Test Plan: harbormaster

 Reviewers: austin, bgamari

 Reviewed By: bgamari

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D3399
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13426#comment:22>
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