[LLVMdev] Regression in 3.4's register allocator?

[Tom Stellard]

On Sun, Jun 01, 2014 at 10:45:18PM +0200, Niklas Therning wrote:
> I think we have located the revision which fixes this regression: r206094
> (or commit 6bb00df in llvm-mirror on GitHub). I have attached a patch which
> can be applied to the current release_34 branch (tested against the
> release_34 branch in llvm-mirror). With this patch the attached
> reg-alloc-test.ll file doesn't fail with the "LLVM ERROR: ran out of
> registers during register allocation" error any longer. I haven't run any
> llvm tests to make sure this patch doesn't break anything else but as far
> as I can see it doesn't at least break anything when used in RoboVM.
> 
> Is it too late to get this into 3.4.2? Is there anything else I can do to
> make it easier for you to include this patch in 3.4.2 or the next possible
> point release?
> 

Hi Niklas,

Unfortunately, it is too late to get this into 3.4.2.  With the 3.5
release coming soon, I wasn't planning on doing another 3.4 point
release.

I took a quick look at the patch, would it be possible to work around
this by adding a value to the FeatureString when invoking LLVM?

-Tom

> 
> 
> On Wed, May 14, 2014 at 3:25 PM, Renato Golin <renato.golin at linaro.org>
> wrote:
> 
> > On 14 May 2014 14:15, Niklas Therning <niklas at therning.org> wrote:
> > > I can confirm that this regression has been fixed in trunk. Should I
> > report
> > > this as a bug in 3.4?
> >
> > The 3.4.2 release is coming, you might want to consider finding the
> > patches responsible for the fix and proposing it for back-porting.
> >
> > Please email Tom (cc'd) if you end up with a proposal.
> >
> > cheers,
> > --renato
> >