[commit: ghc] wip/12368: DmdAnal: Add a final, safe iteration (98da9fa)

[git at git.haskell.org]

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

On branch  : wip/12368
Link       : http://ghc.haskell.org/trac/ghc/changeset/98da9faa633a7faa20c320a7eae8c3f8646c186f/ghc

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

commit 98da9faa633a7faa20c320a7eae8c3f8646c186f
Author: Joachim Breitner <mail at joachim-breitner.de>
Date:   Thu Jul 7 11:23:48 2016 +0200

    DmdAnal: Add a final, safe iteration
    
    this fixes #12368.
    
    It also refactors dmdFix a bit, removes some redundancies (such as
    passing around an strictness signature right next to an id, when that id
    is guaranteed to have been annotated with that strictness signature).
    
    Note that when fixed-point iteration does not terminate, we
    conservatively delete their strictness signatures (set them to nopSig).
    But this loses the information on how its strict free variables are
    used!
    
    Lazily used variables already escape via lazy_fvs. We ensure that in the
    case of an aborted fixed-point iteration, also the strict variables are
    put there (with a conservative demand of topDmd).
    
    Differential Revision: https://phabricator.haskell.org/D2392


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

98da9faa633a7faa20c320a7eae8c3f8646c186f
 compiler/basicTypes/Demand.hs            |   7 +-
 compiler/basicTypes/VarEnv.hs            |   5 +-
 compiler/stranal/DmdAnal.hs              | 188 ++++++++++++++++++-------------
 compiler/utils/UniqFM.hs                 |   6 +
 testsuite/tests/stranal/should_run/all.T |   3 +-
 5 files changed, 128 insertions(+), 81 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 98da9faa633a7faa20c320a7eae8c3f8646c186f