[GHC] #4012: Compilation results are not deterministic
GHC
ghc-devs at haskell.org
Mon Jun 13 18:31:38 UTC 2016
#4012: Compilation results are not deterministic
-------------------------------------+-------------------------------------
Reporter: kili | Owner: niteria
Type: bug | Status: new
Priority: high | Milestone: 8.2.1
Component: Compiler | Version: 6.12.2
Resolution: | Keywords:
Operating System: Unknown/Multiple | Architecture:
| Unknown/Multiple
Type of failure: Other | Test Case:
Blocked By: 11362 | Blocking:
Related Tickets: #10424 | Differential Rev(s): Phab:D910,
| Phab:D1073, Phab:D1133, Phab:D1192,
| Phab:D1268, Phab:D1360, Phab:D1373,
Wiki Page: | Phab:D1396, Phab:D1457, Phab:D1468,
DeterministicBuilds | Phab:D1487, Phab:D1504, Phab:D1508
-------------------------------------+-------------------------------------
Comment (by Bartosz Nitka <niteria@…>):
In [changeset:"0497ee504cc9ac5d6babee9b98bf779b3fc50b98/ghc" 0497ee5/ghc]:
{{{
#!CommitTicketReference repository="ghc"
revision="0497ee504cc9ac5d6babee9b98bf779b3fc50b98"
Make the Ord Module independent of Unique order
The `Ord Module` instance currently uses `Unique`s for comparison.
We don't want to use the `Unique` order because it can introduce
nondeterminism.
This switches `Ord ModuleName` and `Ord UnitId` to use lexicographic
ordering
making `Ord Module` deterministic transitively.
I've run `nofib` and it doesn't make a measurable difference.
See also Note [ModuleEnv determinism and performance].
Test Plan:
./validate
run nofib: P112
Reviewers: simonpj, simonmar, austin, bgamari
Subscribers: thomie
Differential Revision: https://phabricator.haskell.org/D2030
GHC Trac Issues: #4012
}}}
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:209>
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