[LLVMdev] Testing LLVM on OS X

[Patrick Flanagan]

On May 6, 2004, at 12:01 AM, Chris Lattner wrote:

> On Wed, 5 May 2004, Patrick Flanagan wrote:
>>>> and I'm not convinced that GCC is doing a very good job (ie, without
>>>> syntactic loops).
>>>
>>> Yup, this is EXACTLY what is going on.
>>
>> Interesting. Now that you mention it, I do recall thinking the loops
>> that llvm generated looked a bit different than the gcc loops. I'll go
>> back and take another look, but this might explain some of that
>> discrepancy.
>
> I'll try to put together a "solution" for this some time in the near
> future.  Since right now we depend on the CBE for performance, and 
> because
> so many people use GCC, we really are REQUIRED to cover for this if we
> want to provide competitive performance.  I imagine that this should
> improve loop-intensive codes substantially.
>


What is the rationale for doing the llvm code -> c backend code -> 
compile that thing anyway? If the person specifies that -native-cbe, 
why not just compile the code as is?


>> inlining stuff
>

I did play around with the inlining threshold to make file_read and zip 
get inlined in more spots. This didn't make any difference though, so 
the main problem seems to be the loops as you pointed out in last 
email. Wouldn't this be a non-issue if the -native-cbe flag just meant 
compile the code given rather than going through llvm code and the c 
backend?

>> Also, on an unrelated note, I could have sworn all those benchmarks
>> compiled but I went back to double check and I saw that there were a
>> few problems.
>
> Okay.
>
>> 253.perlbmk builds fine but crashes when running through the spec 
>> test.
>> I recall seeing a note a few places on the website that said perlbmk
>> didn't work properly due to a longjmp bug, is that still a known bug 
>> or
>> should I try running that through a debugger to find the problem?
>
> Hrm, that's an interesting question.  To get setjmp/longjmp working, 
> you
> have to pass -enable-correct-eh-support into the 'llc' command.  I 
> don't
> think there is any way to get the -native-cbe option to do this, so if 
> you
> want to test it, you'll have to use the commands above to compile it by
> hand. :(

I built perlbmk by manually and specified the 
-enable-correct-eh-support option. Looks like that test is working fine 
now.

Patrick