[GHC] #13564: Why does memory usage increase so much during CoreTidy?

[GHC]

#13564: Why does memory usage increase so much during CoreTidy?
-------------------------------------+-------------------------------------
        Reporter:  rwbarton          |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            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:D3516,
       Wiki Page:                    |  Phab:D3524
-------------------------------------+-------------------------------------

Comment (by Ben Gamari <ben@…>):

 In [changeset:"b3da6a6c3546562d5c5e83b8af5d3fd04c07e0c1/ghc"
 b3da6a6c/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="b3da6a6c3546562d5c5e83b8af5d3fd04c07e0c1"
 CoreTidy: Don't seq unfoldings

 Previously we would force uf_is_value and friends to ensure that we didn't
 retain a reference to the pre-tidying template, resulting in a space leak.
 Instead, we now just reinitialize these fields (despite the fact that they
 should not have changed). This may result in a bit more computation, but
 most of
 the time we won't ever evaluate them anyways, so the damage shouldn't be
 so bad.

 See #13564.
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13564#comment:9>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler