[Mesa-dev] wider registers in llvmpipe

[Jose Fonseca]

----- Original Message -----
> On Sun, Oct 7, 2012 at 3:37 PM, Stéphane Marchesin
> <stephane.marchesin at gmail.com> wrote:
> > On Wed, Jul 18, 2012 at 8:35 AM, Jose Fonseca <jfonseca at vmware.com>
> > wrote:
[...]
> >> I can't reproduce the failures here neither, nor with softpipe +
> >> draw llvm
> >>
> >> I also considered that this could be 32bits specific, but that
> >> doesn't seem to be the case.  It seems i915g specific AFAICT.
> >>
> >> Stephane I'll gonna need to to provide more details (in
> >> particular, stack dump of the crashes, dumps w/
> >> GALLIVM_DEBUG=tgsi,ir,asm environment var before/after this
> >> change, see if not advertise half float solve the issue) to pin
> >> point this. If you wanna open a bug and follow this on fdo that's
> >> fine by me.
> >>
> >
> > Unearthing an old item now that I have time for it. I can reproduce
> > with llvmpipe on the same machine, hopefully the backtrace rings a
> > bell, I'll also try to dig further into it. Running draw-vertices
> > in
> > gdb I get:
> 
> So I dug into it a bit more, and this seems to be an LLVM 2.8 issue.
> LLVM 3.1 works fine here. I think we should just disallow LLVM <=
> 2.8.

Ok. Good to know.

LLVM 2.8 has several known issues. If your LLVM build doesn't include the fixes from http://cgit.freedesktop.org/~jrfonseca/llvm/log/?h=backports_28 then it is possible that one of them is the culprit here.

If you look at http://cgit.freedesktop.org/~jrfonseca/llvm/log/?h=backports_31 you'll see that vanilla LLVM 3.1 is not perfect either. No unpatched version is.

Either way, I'm fine if you want to require 2.9+ on automake.

But I need to continue support LLVM 2.6 on scons for a bit longer.

Jose