[lldb-dev] Test suite failures on Fedora Linux?

Pavel Labath via lldb-dev lldb-dev at lists.llvm.org
Fri Mar 29 06:55:31 PDT 2019

On 27/03/2019 16:38, Pavel Labath via lldb-dev wrote:
> On 26/03/2019 14:48, David Zarzycki via lldb-dev wrote:
>>> On Mar 26, 2019, at 3:07 AM, Jan Kratochvil
>>> <jan.kratochvil at redhat.com> wrote:
>>> On Mon, 25 Mar 2019 19:47:36 +0100, David Zarzycki via lldb-dev
>>> wrote:
>>>> Also, given that two of the test failures are Intel specific (the
>>>> mxcsr register write failures), what class of hardware do you
>>>> use? My workstation is Skylake-SP based, if it matters.
>>> OK, I agree it PASSes for me on Haswell-EP (E5-2630v3) but it also
>>> FAILs for me on Kaby Lake Refresh (i7-8650U).  Also
>>> kernel-5.0.3-200.fc29.x86_64.
>> It looks like this is a known issue:
>> https://bugs.llvm.org/show_bug.cgi?id=39958
> Ok, so I've managed to get a hold of a machine which reproduces this
> problem. It's a debian based system running linux 4.19, which should
> confirm that this is a hardware issue.
> I'll try to find some time to diagnose this later this week. My guess is
> that we're just setting some mxcsr value that these CPUs don't like, and
> we need to be more conservative in what we write in the tests.

Ok, the issue was a bit more complex than I anticipated, but I think I 
managed to create a patch <https://reviews.llvm.org/D59991> that fixes 
that, as well as prevents something similar from happening in the future 
(for the curious, a there's a longer description of the problem in the 

Jan, David, this patch was enough to fix the test suite failures on the 
machine that I got access to, but I'd appreciate it if you could check 
that it also fixes things on your end.

thank you,

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