[GHC] #14637: Simplifier Ticks Exhausted when compiling with profiling

[GHC]

#14637: Simplifier Ticks Exhausted when compiling with profiling
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        Reporter:  cfhammill         |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Linux             |         Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 Thanks.  I can repro this.  For the record, changing `bug2.hs` to define
 just
 {{{
 foo :: Rec Identity
                '["policyID" :-> Int, "statecode" :-> String, "county" :->
 String,
                  "eq_site_limit" :-> Double, "hu_site_limit" :-> Double,
                  "fl_site_limit" :-> Double, "fr_site_limit" :-> Double,
                  "tiv_2011" :-> Double, "tiv_2012" :-> Double,
                  "eq_site_deductible" :-> Bool, "hu_site_deductible" :->
 Double,
                  "fl_site_deductible" :-> Bool, "fr_site_deductible" :->
 Bool,
                  "point_latitude" :-> Double, "point_longitude" :->
 Double,
                  "line" :-> String, "construction" :-> String,
                  "point_granularity" :-> Int, "statecode" :-> String,
                  "county" :-> String, "eq_site_limit" :-> Double,
                  "hu_site_limit" :-> Double, "fl_site_limit" :-> Double,
                  "fr_site_limit" :-> Double, "tiv_2011" :-> Double,
                  "tiv_2012" :-> Double, "eq_site_deductible" :-> Bool,
                  "hu_site_deductible" :-> Double, "fl_site_deductible" :->
 Bool,
                  "fr_site_deductible" :-> Bool, "point_latitude" :->
 Double,
                  "point_longitude" :-> Double, "line" :-> String,
                  "construction" :-> String, "point_granularity" :-> Int]
 foo = mergeRows (undefined :: FL2) (undefined :: FL2)
 }}}
 without main or the (overloaded) `print`, is enough to make it go out to
 lunch.

 Moreover, this happens in the very first iteration of the simplifier.

 I have not got further yet.  Next steps: try with a smaller `FL2` and see
 how the compile time (or, more precisely, simplifier ticks) goes non-
 linear.

 I say "simplifier tickes" because I would not have been suprised at non-
 linearity in the type checker... we are manipulating sets as lists in the
 type system.  But I'm more surprised at non-linearity in the simplifier.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14637#comment:4>
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