[GHC] #5433: Compiler generates invalid assembly with "bad register name"

[GHC]

#5433: Compiler generates invalid assembly with "bad register name"
---------------------------------+------------------------------------------
    Reporter:  bos               |        Owner:  simonmar          
        Type:  bug               |       Status:  new               
    Priority:  highest           |    Milestone:  7.4.1             
   Component:  Compiler          |      Version:  7.2.1             
    Keywords:                    |     Testcase:                    
   Blockedby:                    |   Difficulty:                    
          Os:  Unknown/Multiple  |     Blocking:                    
Architecture:  x86               |      Failure:  Compile-time crash
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Comment(by marlowsd@…):

 commit 3572c11958bf77e0797a190efab68cf80895f2ac
 {{{
 Author: Simon Marlow <marlowsd at gmail.com>
 Date:   Thu Oct 6 11:57:52 2011 +0100

     Use a custom dead-code analyser instead of calling the occurrence
 analyser.

     In CorePrep we used to call the occurrence analyser to drop dead code
     (see Note [Dead code in CorePrep]), but the occurrence analyser
     sometimes introduces new let bindings for case binders.  This was
     leading to the bug in #5433: the let binding introduced was for an
     unlifted value, and the code generator is not expecting to see let
     bindings of unlifted values (CorePrep is supposed to eliminate them).
     We don't want this let binding anyway, so instead of using the
     occurrence analyser here we have a simple custom dead-code analyser.

  compiler/coreSyn/CorePrep.lhs |   90
 +++++++++++++++++++++++++++++++++-------
  1 files changed, 74 insertions(+), 16 deletions(-)
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5433#comment:4>
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