[GHC] #7978: Profiling broken

[GHC]

#7978: Profiling broken
--------------------------------------------+------------------------------
        Reporter:  gmainland                |            Owner:
            Type:  bug                      |           Status:  new
        Priority:  highest                  |        Milestone:  7.8.1
       Component:  Compiler                 |          Version:  7.7
      Resolution:                           |         Keywords:
Operating System:  Unknown/Multiple         |     Architecture:
 Type of failure:  GHC doesn't work at all  |  Unknown/Multiple
       Test Case:                           |       Difficulty:  Unknown
        Blocking:                           |       Blocked By:
                                            |  Related Tickets:
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Comment (by ezyang):

 My guess is cardinality analysis is tickling a latent bug in the code
 generator related to generating code for non-updatable thunks.  If you
 disable cardinality analysis in the following way:

 {{{
 diff --git a/compiler/stgSyn/CoreToStg.lhs b/compiler/stgSyn/CoreToStg.lhs
 index 1395c22..414a6d8 100644
 --- a/compiler/stgSyn/CoreToStg.lhs
 +++ b/compiler/stgSyn/CoreToStg.lhs
 @@ -807,7 +807,7 @@ mkStgRhs rhs_fvs srt bndr binder_info rhs
                    (getFVs rhs_fvs)
                    upd_flag srt [] rhs
    where
 -   upd_flag = getUpdateFlag bndr
 +   upd_flag = Updatable
    {-
      SDM: disabled.  Eval/Apply can't handle functions with arity zero
 very
      well; and making these into simple non-updatable thunks breaks other
 }}}

 I think the profiling build goes through as desired.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7978#comment:13>
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