[GHC] #8319: Simplifier ticks exhausted (need -fsimpl-tick-factor=955)

[GHC]

#8319: Simplifier ticks exhausted (need -fsimpl-tick-factor=955)
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        Reporter:  ruudkoot            |            Owner:
            Type:  bug                 |           Status:  new
        Priority:  normal              |        Milestone:
       Component:  Compiler            |          Version:  7.6.3
      Resolution:                      |         Keywords:
Operating System:  Unknown/Multiple    |     Architecture:
 Type of failure:  Compile-time crash  |  Unknown/Multiple
       Test Case:                      |       Difficulty:  Unknown
        Blocking:                      |       Blocked By:
                                       |  Related Tickets:
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Comment (by simonpj):

 I've found out what is going on.  (What follows is an aide-memoire for
 me.)

 There is a huge function of this form:
 {{{
   f = \x -> let BIG BIG BIG
             in case ... of
                   p1 -> (# a, b, c, d #)
                   p2 -> (# a, b, c, d #)
                 ...
                   p2 -> (# a, b, c, d #)
 }}}
 As things stand, in `CoreUnfold`, unboxed tuples don't count towards the
 size of the express, but DO count towards the result discount. See `Note
 [Unboxed tuple size and result discount]`.  As a result, functions like
 `f` can be very big, but have a massive result discount, and hence can be
 inlined like crazy.

 This blows up the size of the test program.

 The obvious solution is to nuke the discount, but I need check performance
 runs carefully.  This comment just records my progress.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8319#comment:2>
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