[GHC] #2790: Use -fregs-graph by default

[GHC]

#2790: Use -fregs-graph by default
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    Reporter:  igloo             |        Owner:  benl        
        Type:  task              |       Status:  new         
    Priority:  high              |    Milestone:  6.14.1      
   Component:  Compiler          |      Version:  6.8.3       
    Keywords:                    |     Testcase:              
   Blockedby:                    |   Difficulty:  Unknown     
          Os:  Unknown/Multiple  |     Blocking:              
Architecture:  Unknown/Multiple  |      Failure:  None/Unknown
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Comment(by benl):

 Yes, but I've only tested it on OSX with the testsuite. You might want to
 do a full hackage build on Linux first if you're setup for it.

 Apart from with the vector library, it doesn't make much difference to the
 runtimes. Perhaps we want to enable -fregs-graph for -O and -fregs-
 iterative for -O2. At least that would stop all the allocators (including
 the linear one) from rotting in the future.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2790#comment:24>
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