[Mesa-dev] [Bug 106231] llvmpipe blends produce bad code after llvm patch https://reviews.llvm.org/D44785

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=106231

Roland Scheidegger <sroland at vmware.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jfonseca at vmware.com,
                   |                            |sroland at vmware.com

--- Comment #1 from Roland Scheidegger <sroland at vmware.com> ---
(In reply to Tom Hudson from comment #0)
> https://reviews.llvm.org/D44785 changed the way adds, addus, subs, subus are
> handled.
> 
> llvmpipe issues llvm.x86.sse2.padds and llvm.x86.sse2.psubs in
> src/gallium/auxiliary/gallivm/lp_bld_arit.c:lp_build_add() and
> lp_build_sub().
> 
> After D44785 landed, lp_test_blend.c started crash every time it entered
> LLVM-compiled code for type=u8nx16.
> 
> Commenting out the issues of padds/psubs avoids this crash. The LLVM
> project, in discussing the bug at https://reviews.llvm.org/D44785, suspects
> that the cause may be because llvmpipe is "missing the autoupgrade stage"?

Autoupgrade doesn't work for jit code (at least I wouldn't know how, and it
never has in the past), so the way we handled disappearing of intrinsics in the
past was to just not use them any more (for newer llvm versions) and do
essentially the same as what autoupgrade would do, and we'll have to do the
same here.

I am however sure that in the past when intrinsics disappeared, it would
complain when compiling the IR, rather than just call 0 function in the
compiled code. Which is of course much nicer...
For instance when the min/max (integer) intrinsics disappared:
https://bugs.llvm.org/show_bug.cgi?id=28176
But I'm not sure if just calling 0 function now is expected due to some llvm
changes, but if it is that's definitely making everybody's life harder...

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/mesa-dev/attachments/20180425/71f68974/attachment-0001.html>