[commit: ghc] master: Lift constructor tag allocation out of a loop (dbdf77d)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/dbdf77d92c9cd0bbb269137de0bf8754573cdc1e/ghc

>---------------------------------------------------------------

commit dbdf77d92c9cd0bbb269137de0bf8754573cdc1e
Author: Bartosz Nitka <niteria at gmail.com>
Date:   Fri Jan 5 15:20:05 2018 +0000

    Lift constructor tag allocation out of a loop
    
    Before this change, for each constructor that we want
    to allocate a tag for we would traverse a list of all
    the constructors in a datatype to determine which tag
    a constructor should get.
    
    This is obviously quadratic and for datatypes with 10k
    constructors it actually makes a big difference.
    
    This change implements the plan outlined by @simonpj in
    https://mail.haskell.org/pipermail/ghc-devs/2017-October/014974.html
    which is basically about using a map and constructing it outside the
    loop.
    
    One place where things got a bit awkward was TysWiredIn.hs,
    it would have been possible to just assign the tags by hand, but
    that seemed error-prone to me, so I decided to go through a map
    there as well.
    
    Test Plan:
    ./validate
    On a file with 10k constructors
    Before:
       8,130,522,344 bytes allocated in the heap
      Total   time    3.682s  (  3.920s elapsed)
    After:
       4,133,478,744 bytes allocated in the heap
      Total   time    2.509s  (  2.750s elapsed)
    
    Reviewers: simonpj, bgamari
    
    Reviewed By: simonpj
    
    Subscribers: goldfire, rwbarton, thomie, simonmar, carter, simonpj
    
    GHC Trac Issues: #14657
    
    Differential Revision: https://phabricator.haskell.org/D4289


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dbdf77d92c9cd0bbb269137de0bf8754573cdc1e
 compiler/basicTypes/DataCon.hs                    |  5 ++---
 compiler/iface/BuildTyCl.hs                       | 13 +++++++++---
 compiler/iface/TcIface.hs                         |  5 ++++-
 compiler/prelude/TysWiredIn.hs                    | 10 ++++++++-
 compiler/typecheck/TcTyClsDecls.hs                | 13 +++++++-----
 compiler/types/TyCon.hs                           | 25 ++++++++++++++++++++++-
 compiler/vectorise/Vectorise/Generic/PData.hs     |  4 ++++
 compiler/vectorise/Vectorise/Type/TyConDecl.hs    |  2 ++
 testsuite/tests/perf/compiler/all.T               | 12 +++++++++++
 testsuite/tests/perf/compiler/genManyConstructors | 25 +++++++++++++++++++++++
 10 files changed, 100 insertions(+), 14 deletions(-)

Diff suppressed because of size. To see it, use:

    git diff-tree --root --patch-with-stat --no-color --find-copies-harder --ignore-space-at-eol --cc dbdf77d92c9cd0bbb269137de0bf8754573cdc1e