[LLVMdev] Testing LLVM on OS X

Patrick Flanagan valtrain at mac.com
Fri May 14 09:09:02 PDT 2004

> Okay, I changed the C backend to emit syntactic loops around the real
> loops, and it seems to make a big difference.  LLVM now generates this
> code (note that the actual loop is not actually responsible for control
> flow, it's unreachable):
> ... which is exactly what we want.  Patrick, I would appreciate it if 
> you
> could rerun your tests on PPC and let me know if this helps.  :)
> -Chris

Ok, I ran through the SPEC suite with the new LLVM. Unfortunately, it 
doesn't seem to have made anything faster. Most of the benchmarks are 
the same (or within noise) but gzip got even slower. I put together a 
quick page showing the SPEC scores and their differences between LLVM 
versions. You can see that here: 

Due to the aforementioned finals, I haven't gotten a chance to do any 
profiling or try to investigate why the syntactic loop thing made it 
slower but I'll try to look at that some more this weekend.


More information about the llvm-dev mailing list