[GHC] #10370: Compile time regression in OpenGLRaw

[GHC]

#10370: Compile time regression in OpenGLRaw
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        Reporter:  michalt           |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Changes (by michalt):

 * cc: michalt (added)


Comment:

 @rwbarton Thanks a lot for a smaller use case!

 I had a brief look at generated Core (for both 7.8.4 and HEAD) and
 couldn't really find anything suspicious. Also core stats seem similar --
 we generate almost identical number of terms/types/coercions. (although
 I'm far from an expert so take that with a grain of salt)

 The good news is that I managed to narrow it down to
 b8392ae76a6d39c57be94b5ba041c450ab479e2b
 What I did: initially I just wanted to bisect but couldn't really get GHC
 to build before Jan 2015. So I checkout a commit from early January (the
 problem is reproducible there) and reverted the above patch (at which
 point the problem is no longer reproducible).

 I'll try to look into that commit tomorrow.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10370#comment:7>
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