[GHC] #4957: Simplifier failes to eliminate redundant boxing/unboxing

[GHC]

#4957: Simplifier failes to eliminate redundant boxing/unboxing
---------------------------------------------+------------------------------
  Reporter:  simonpj                         |          Owner:                  
      Type:  bug                             |         Status:  closed          
  Priority:  normal                          |      Milestone:                  
 Component:  Compiler                        |        Version:  7.0.1           
Resolution:  fixed                           |       Keywords:                  
  Testcase:  simplCore/should_compile/T4957  |      Blockedby:                  
Difficulty:                                  |             Os:  Unknown/Multiple
  Blocking:                                  |   Architecture:  Unknown/Multiple
   Failure:  None/Unknown                    |  
---------------------------------------------+------------------------------
Changes (by simonpj):

  * status:  new => closed
  * testcase:  => simplCore/should_compile/T4957
  * resolution:  => fixed


Comment:

 Fixed by
 {{{
 Mon Feb 14 03:11:51 PST 2011  simonpj at microsoft.com
   * Better case-of-case transformation

   The ThunkSplitting idea in WorkWrap wasn't working at all,
   leading to Trac #4957.  The culprit is really the simplifier
   which was combining the wrong case continuations. See
   Note [Fusing case continuations] in Simplify.

     M ./compiler/simplCore/Simplify.lhs -10 +48
     M ./compiler/stranal/WorkWrap.lhs +5
 }}}
 Test added also.

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4957#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler