[LLVMdev] Turning on/off instruction extensions

[Hal Finkel]

On Tue, 2011-12-13 at 13:00 +0100, Pablo Barrio wrote:
> On 12/12/11 17:07, Hal Finkel wrote:
> > On Mon, 2011-12-12 at 12:59 +0100, Pablo Barrio wrote:
> >>
> >> I'm still getting the following error:
> >>
> >> ---
> >> 1 out of 3 hunks FAILED -- saving rejects to file
> >> lib/Transforms/IPO/PassManagerBuilder.cpp.rej
> >> ---
> >>
> >> I'm using LLVM rev. 146369 (current trunk). Is it the same as you? If
> >> not, tell me your revision and I'll try again.
> > LLVM develops quickly ;) -- The patch you have is again out of sync.
> > I'll send an updated patch to the list soon.
> 
> Great! I'll wait for the new patch. Thanks for the help!
> 
> One more question: I'm currently using dragonegg for autovectorization, 
> but I cannot get any vector longer than 4 elements for floats and 2 for 
> doubles. I suspect this is because my processor doesn't support bigger 
> vectors. However, I would like to generate bigger vectors into the LLVM 
> IR, and then decide what to do with them in the backend. Can your 
> vectorizer do something like that?

Yes, just pass the flag: -bb-vectorize-vector-bits=256 (or whatever). It
will then try to generate vectors *up to* that size (could be smaller,
but not larger).

 -Hal

> 
> Thanks,
> Pablo
> 
> >> Suggestion: would it be possible to have a patch for the stable version
> >> (LLVM 3.0)?
> > I'll add that to my TODO list, but I probably won't get to it until
> > after the current patch finishes code review. I'll worry about
> > backporting after that.
> >
> >   -Hal
> >
> >> Thanks ahead,
> >> Pablo
> 
> 

-- 
Hal Finkel
Postdoctoral Appointee
Leadership Computing Facility
Argonne National Laboratory