[GHC] #8900: Strictness analysis regression

[GHC]

#8900: Strictness analysis regression
--------------------------------------------+------------------------------
        Reporter:  tibbe                    |            Owner:
            Type:  bug                      |           Status:  closed
        Priority:  normal                   |        Milestone:
       Component:  Compiler                 |          Version:  7.8.1-rc2
      Resolution:  fixed                    |         Keywords:
Operating System:  MacOS X                  |     Architecture:  x86_64
 Type of failure:  Runtime performance bug  |  (amd64)
       Test Case:                           |       Difficulty:  Unknown
        Blocking:                           |       Blocked By:
                                            |  Related Tickets:
--------------------------------------------+------------------------------

Comment (by tibbe):

 Replying to [comment:24 simonmar]:
 > I was surprised by this, because I would expect HEAD and 7.6.3 to
 generate very similar code with respect to spilling before a call.  #8905
 is about an improvement we can make in the new code generator, that wasn't
 possible in the old codegen.

 My mistake. I've been reading too much Cmm lately.

 > they look identical to me modulo reordering and things falling into
 different stack slots.  Maybe the problematic bit is somewhere else -
 could you point to it?

 I have no idea then. There's a lot of Cmm and diff tools don't work well
 because blocks have been reordered a lot between 7.6.3 and HEAD. Since the
 difference is so small I suggest we ignore it for now. I'm more interested
 in getting #8905 into a production-ready state.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8900#comment:25>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler