[GHC] #778: building with gcc-4.1.1 causes ghc to enter infinite allocation loop

[GHC]

#778: building with gcc-4.1.1 causes ghc to enter infinite allocation loop
-----------------------------+----------------------------------------------
  Reporter:  guest           |          Owner:       
      Type:  bug             |         Status:  new  
  Priority:  normal          |      Milestone:  6.4.3
 Component:  Runtime System  |        Version:  6.4.2
  Severity:  normal          |     Resolution:       
  Keywords:  memory gcc-4    |             Os:  Linux
Difficulty:  Unknown         |   Architecture:  x86  
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Changes (by dcoutts at gentoo.org):

  * architecture:  Unknown => x86
  * component:  Compiler => Runtime System
  * keywords:  memory => memory gcc-4
  * summary:  memory leak => building with gcc-4.1.1 causes ghc to enter
              infinite allocation loop

Comment:

 http://bugs.gentoo.org/show_bug.cgi?id=135651

 I can repoduce this bug using a stable gentoo x86 profile with gcc-4.1.1
 and plain CFLAGS="-O2 -pipe".

 The symptoms are the same, after compiling ghc-6.4.2 using ghc-6.4.2 with
 gcc-4.1.1 then upon running the freshly built ghc-6.4.2 it gets part way
 through initialisation and then goes into an infinite loop allocating more
 and more memory (in the usual 1Mb MBlocks) until the kernel refuses to
 allocate any more and the rts terminates.

 I'm just testing with gcc-4.1.0 to see if it's present there too.

 So it looks like this isn't just a bad combination of agressive CFLAGS but
 is going to be a real problem once gcc-4.x gets more popular.

 So the 6.4.3 milestone seems appropriate, it'd be good to investigate it
 more thouroughly in that timeframe.

 My suspicion is that gcc-4.1.1 is mis-compiling part of the rts, that or
 the rts is breaking some strict C rule that gcc is now relying upon (eg
 aliasing). So I'm changing the summary and component to match.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/778>
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