On 21.08.2014 18:10, Henri Verbeet wrote:
On 21 August 2014 04:56, Michel Dänzer <mic...@daenzer.net> wrote:
On 21.08.2014 04:29, Henri Verbeet wrote:
For whatever it's worth, I have been avoiding radeonsi in part because
of the LLVM dependency. Some of the other issues already mentioned
aside, I also think it makes it just painful to do bisects over
moderate/longer periods of time.
More painful, sure, but not too bad IME. In particular, if you know the
regression is in Mesa, you can always use a stable release of LLVM for
the bisect. You only need to change the --with-llvm-prefix= parameter to
Mesa's configure for that. Of course, it could still be mildly painful
if you need to go so far back that the current stable LLVM release
wasn't supported yet. But how often does that happen? Very rarely for me.
Sure, it's not impossible, but is that really the kind of process you
want users to go through when bisecting a regression?
I appreciate your theoretical concern, but in practice, people don't
seem to have trouble bisecting radeonsi regressions in general.
Without LLVM, I'm not sure there would be a driver you could avoid. :)
R600g didn't really exist either, and that one seems to have worked
out fine. I think in a large part because of work done by Jerome and
Dave in the early days, but regardless. From what I've seen from SI, I
don't think radeonsi needed to be a separate driver to start with, and
while its ISA is certainly different from R600-Cayman, it doesn't
particularly strike me as much harder to work with.
That's getting off-topic, but most of the code that can be shared
between radeonsi and r600g is shared now.
Back to the more immediate topic though, I think think that on
occasion the discussion is framed as "Is there any reason using LLVM
IR wouldn't work?", while it would perhaps be more appropriate to
think of as "Would using LLVM IR provide enough advantages to justify
adding a LLVM dependency to core Mesa?".
Unless you can show me anyone who would prefer swrast or softpipe over
llvmpipe for software rendering tests, I'd argue that there effectively
already is such a dependency. There's no real indication that using LLVM
IR for the purposes discussed in this thread would require a stricter
dependency on LLVM than we already have for llvmpipe.
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer
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