[GHC] #5113: Huge performance regression of 7.0.2, 7.0.3 and HEAD over 7.0.1 and 6.12 (MonoLocalBinds)

[GHC]

#5113: Huge performance regression of 7.0.2, 7.0.3 and HEAD over 7.0.1 and 6.12
(MonoLocalBinds)
--------------------------------------------+-------------------------------
    Reporter:  daniel.is.fischer            |        Owner:                         
        Type:  bug                          |       Status:  new                    
    Priority:  normal                       |    Milestone:                         
   Component:  Compiler                     |      Version:  7.0.3                  
    Keywords:  performance, MonoLocalBinds  |     Testcase:                         
   Blockedby:                               |   Difficulty:                         
          Os:  Linux                        |     Blocking:                         
Architecture:  x86                          |      Failure:  Runtime performance bug
--------------------------------------------+-------------------------------

Comment(by simonpj):

 I'm lost. The `inc` you give above is indeed polymorphic in both the monad
 and the index type, and (unless specialised or inlined) will probably
 perform much worse than the polymorphic vresion.

 Can you give a concrete module that, when compiled, gives much worse code
 with HEAD than 6.12?

 Thanks

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5113#comment:2>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler