[Beignet] Does LLVM 3.6 still hit a bug?

[Yang, Rong R]

The patch has been merged, and have sent a patch update the README.
I will add the LLVM 3.7 information after have the LLVM 3.7 performance date.

> -----Original Message-----
> From: Beignet [mailto:beignet-bounces at lists.freedesktop.org] On Behalf Of
> Zou, Nanhai
> Sent: Monday, November 2, 2015 14:56
> To: Rebecca N. Palmer; beignet at lists.freedesktop.org
> Subject: Re: [Beignet] Does LLVM 3.6 still hit a bug?
> 
> We found that it's a miss understanding of a corner case in type conversion,
> not a llvm bug.
> In that case the cl kernel try to convert an overflowed float value to ulong
> 
> e.g.
> ulong dst = (ulong)1.8446744073709552e+19f; // this is an overflowed ulong
> value
> 
> with llvm3.5 the result value is ULONG_MAX with llvm3.6 the result value is
> undef.
> 
> This cause one of the conformance sub test report error with llvm 3.6
> 
> Please check the patch for the fix.
> 
> [Beignet] [PATCH] LibOcl: Fix float convert to long/ulong bug.
> We will merge the patch soon
> 
> Thanks
> Zou Nanhai
> 
> > -----Original Message-----
> > From: Beignet [mailto:beignet-bounces at lists.freedesktop.org] On Behalf
> > Of Rebecca N. Palmer
> > Sent: Monday, November 02, 2015 6:23 AM
> > To: beignet at lists.freedesktop.org
> > Subject: Re: [Beignet] Does LLVM 3.6 still hit a bug?
> >
> > When was this workaround done (in particular, is beignet 1.1.1
> > affected)?  As the Khronos test suite is non-public, I can't test this myself.
> >
> > Debian have now announced an intention to remove LLVM 3.5
> > (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=803643).
> >
> > An alternative option (which I haven't tested yet but appears to be
> > working in
> > Fedora) would be to apply 27522f9..2af7dea and go straight to LLVM 3.7.
> >
> > On 09/10/15 06:56, Zou, Nanhai wrote:
> > > It's a bug related to conditional compare.
> > > The bug will affect the float saturate implementation in Beignet, we
> > > have
> > worked around it.
> > > The bug was exposed by a subcase in Khronos OpenCL conformance test,
> > > we
> > will try to isolate the bug to report to llvm.
> > >
> > > Thanks
> > > Zou Nanhai
> > >
> > >
> > >> -----Original Message-----
> > >> From: Beignet [mailto:beignet-bounces at lists.freedesktop.org] On
> > >> Behalf Of Rebecca N. Palmer
> > >> Sent: Thursday, October 01, 2015 1:32 AM
> > >> To: beignet at lists.freedesktop.org
> > >> Subject: [Beignet] Does LLVM 3.6 still hit a bug?
> > >>
> > >> Debian are planning to switch their default LLVM/Clang to 3.6 soon.
> > >> Is it still the case that
> > >>> The recommended LLVM/CLANG version is 3.5 and/or 3.6. Based on
> our
> > >>> test
> > >> result, LLVM 3.5 has best pass rate on all the test suites. Compare
> > >> to LLVM 3.5, LLVM 3.6 has slightly lower pass rate(caused by one
> > >> front end bug at clang 3.6) but has better performance (3% to 5% up).
> > >> (http://www.freedesktop.org/wiki/Software/Beignet/)?  Where can I
> > >> find code to test for this bug (the test suite doesn't)?
> > >>
> > >> _______________________________________________
> > >> Beignet mailing list
> > >> Beignet at lists.freedesktop.org
> > >> http://lists.freedesktop.org/mailman/listinfo/beignet
> >
> > _______________________________________________
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> > Beignet at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/beignet
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