[GHC] #5272: Performance regression

[GHC]

#5272: Performance regression
---------------------------------+------------------------------------------
    Reporter:  augustss          |       Owner:              
        Type:  bug               |      Status:  new         
    Priority:  normal            |   Component:  Compiler    
     Version:  7.0.4             |    Keywords:              
    Testcase:                    |   Blockedby:              
          Os:  Unknown/Multiple  |    Blocking:              
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown
---------------------------------+------------------------------------------
 The code generated by ghc 7.0.4 is significantly slower than the one for
 ghc 6.12.4 for one of our large programs.

 For a typical benchmark, with ghc-6.12.4 the compiled code ran in 110s and
 with ghc-7.0.4 it runs in 125s.  This is 14% slower.  The program was
 compiled with the same flags in both cases, notably -O2.

 It's difficult to pin down the difference, because when compiled for
 profiling they run at about the same speed.  And as usual the profiling
 information from ghc is wildly inaccurate (with both versions, but in
 different ways).

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5272>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler