[GHC] #12357: Increasing maximum constraint tuple size significantly blows up compiler allocations

[GHC]

#12357: Increasing maximum constraint tuple size significantly blows up compiler
allocations
-------------------------------------+-------------------------------------
        Reporter:  bgamari           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by bgamari):

 Another related efficiency issue can be found in `isDerivedOccName`, which
 decodes the entire `OccName` just to check the first two characters. One
 potential improvement here would be to use a bit in `OccName` (e.g. one of
 the many unused bits belonging to the `Namespace` field) to encode a "is
 derived" flag.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12357#comment:13>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler