[GHC] #4012: Compilation results are not deterministic

[GHC]

#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:  12262
 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:"9858552d607f643db0385be2133a04dd4b5ff753/ghc"
 9858552d/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="9858552d607f643db0385be2133a04dd4b5ff753"
 Use deterministic maps for FamInstEnv

 We turn FamInstEnvs into lists in some places which
 don't directly affect the ABI. That happens in
 family consistency checks and when producing output
 for `:info`. Unfortunately that nondeterminism
 is nonlocal and it's hard to tell locally what it
 affects. Furthermore the envs should be relatively
 small, so it should be free to use deterministic
 maps here. Testing with nofib and ./validate detected
 no difference between UniqFM and UniqDFM.

 GHC Trac: #4012
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:228>
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