Unix VM crash on MacOSX

> Hi--
>
>      On MacOS 10.4.9 (PPC), when I build the Unix VM from the sources at
> squeakvm.org (3.9-8), and try to run Squeak3.9-final-7067, I get:
>
> ***
>
>      Segmentation fault
>
>      53273604 SystemDictionary>lowSpaceWatcher
>      Bus error
>
> ***
>
>      When I run the same image with the pre-built PPC MacOS 3.9-8 VM on
> squeakvm.org, things are normal. When I run that image on Linux with a
> VM built from the same sources, things are normal.
>
>      Any ideas?
>
>
>      thanks!
>
> -C
>

> Craig Latta wrote:
>> Hi Andreas--
>>> From the way you describe it, it sounds like a GCC problem. Have you
>>> tried compiling with -O0 to see if this works?
>>      Aha, that works. Thanks! I'd love to hear details about why
>> optimization messes things up in this situation (I haven't been  
>> paying
>> attention to that issue so far).
>
> I can't say what exactly the problem is but since the VM uses  
> generated code it often utilizes patterns that nobody would ever  
> use in hand-written code. At times, this exposes edge-cases in the  
> optimizer (global CSE is a good candidate) and it's neither the  
> first nor the last time we've seen such effects (Ian has reported  
> various bugs to the GCC people). I would also expect that the PPC  
> backend has seen much less attention recently ;-)
>
> Cheers,
>   - Andreas
>