[Bug c++/46096] Code produces two different outputs when optimized respectively with -O2 and without it.

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46096

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |ebotcazou at gcc dot
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--- Comment #7 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2010-10-20 
14:34:40 UTC ---
> Using a mutex around the reads and writes of shared data will make it work as
> expected, the compiler won't optimise away the read and will re-read the value
> every time.

This is overkill here though, you just need:

  volatile alpha *alpha1 = ( alpha * )data;