[LLVMdev] Regression in 3.4's register allocator?

[Niklas Therning]

I can confirm that this regression has been fixed in trunk. Should I report
this as a bug in 3.4?


On Thu, Apr 24, 2014 at 10:17 PM, Quentin Colombet <qcolombet at apple.com>wrote:

> Hi Niklas,
>
> This works for me with trunk r207129.
>
> We did fix some register allocation issues recently, don’t know which
> change fixes the issue though.
>
> Thanks,
> -Quentin
>
> On Apr 24, 2014, at 1:07 PM, Niklas Therning <niklas at therning.org> wrote:
>
> Hi,
>
> The RoboVM project recently upgraded from LLVM 3.3 to 3.4 and with the new
> version we are sometimes seeing "ran out of registers during register
> allocation" errors when targeting x86 32-bit that we haven't seen before.
> Nothing has changed in our bitcode generator. I have attached an IR file
> which can be used to reproduce this problem. The problem occurs with -O2
> and -disable-fp-elim specified.
>
> Running llc from 3.3 works without problems:
> $ ~/Downloads/clang+llvm-3.3-x86_64-apple-darwin12/bin/llc -mtriple
> i386-unknown-macosx -O2 -disable-fp-elim reg-alloc-test.ll
>
> While llc from 3.4 fails:
> $ ~/Downloads/clang+llvm-3.4-x86_64-apple-darwin10.9/bin/llc -mtriple
> i386-unknown-macosx -O2 -disable-fp-elim reg-alloc-test.ll
> LLVM ERROR: ran out of registers during register allocation
>
> I haven't been able to test this with the latest trunk but I got the same
> error when trying with the 3.4.1 branch.
>
> Has anyone else seen this? Is it a known bug? Or should I report it?
>
> Regards,
> Niklas
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