[Mesa-dev] Mesa (master): Revert "radeon/llvm: Use alloca instructions for larger arrays"

[Marek Olšák]

On Sat, Jul 23, 2016 at 4:07 PM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
> On 22.07.2016 12:08, Michel Dänzer wrote:
>>
>> On 21.07.2016 18:17, Matt Arsenault wrote:
>>>>
>>>> On Jul 21, 2016, at 01:03, Michel Dänzer <michel at daenzer.net
>>>> <mailto:michel at daenzer.net>> wrote:
>>>>
>>>> On 21.07.2016 00:04, Michel Dänzer wrote:
>>>>>
>>>>> On 15.07.2016 05:15, Marek =?UNKNOWN?B?T2zFocOhaw==?= wrote:
>>>>>>
>>>>>> Module: Mesa
>>>>>> Branch: master
>>>>>> Commit: f84e9d749fbb6da73a60fb70e6725db773c9b8f8
>>>>>> URL:
>>>>>>
>>>>>> http://cgit.freedesktop.org/mesa/mesa/commit/?id=f84e9d749fbb6da73a60fb70e6725db773c9b8f8
>>>>>>
>>>>>> Author: Marek Olšák <marek.olsak at amd.com <mailto:marek.olsak at amd.com>>
>>>>>> Date:   Thu Jul 14 22:07:46 2016 +0200
>>>>>>
>>>>>> Revert "radeon/llvm: Use alloca instructions for larger arrays"
>>>>>>
>>>>>> This reverts commit 513fccdfb68e6a71180e21827f071617c93fd09b.
>>>>>>
>>>>>> Bioshock Infinite hangs with that.
>>>>>
>>>>>
>>>>> Unfortunately, this change caused the piglit test
>>>>> shaders at glsl-fs-vec4-indexing-temp-dst-in-loop (and possibly others) to
>>>>> hang my Kaveri. Any ideas for how we can get out of this conundrum?
>>>>
>>>>
>>>> The hang was introduced by LLVM SVN r275934 ("AMDGPU: Expand register
>>>> indexing pseudos in custom inserter"). The good/bad (without/with
>>>> r275934) shader dumps and the GALLIUM_DDEBUG=800 dump corresponding to
>>>> the hang are attached.
>>>>
>>>>
>>>> BTW, even with Marek's change above reverted, I still see some piglit
>>>> regressions compared to last week, but I'm not sure if those are all
>>>> related to the same LLVM change.
>>>>
>>>>
>>>> --
>>>> Earthling Michel Dänzer               |
>>>>               http://www.amd.com <http://www.amd.com/>
>>>> Libre software enthusiast             |             Mesa and X developer
>>>>
>>>> <glsl-fs-vec4-indexing-temp-dst-in-loop.bad><glsl-fs-vec4-indexing-temp-dst-in-loop.good><shader_runner_3339_00000000.txt>
>>>
>>>
>>> This fixes the verifier error in it: https://reviews.llvm.org/D22616
>>
>>
>> This seems to fix the hang, thanks!
>>
>>
>>> This fixes another issue which may be
>>> related: https://reviews.llvm.org/D22556
>>
>>
>> Even with that applied as well, there are still piglit regressions
>> compared to early last week, see the attached dumps (look for "LLVM
>> triggered Diagnostic Handler:").
>
>
> Looks like the "rewrite undef" part of the Two Address Instruction Pass also
> needs to be adjusted -- I've attached a bugpoint-reduced test case.
>
> Also, the hang that motivated the original revert in Mesa should be fixed
> with https://reviews.llvm.org/D22673 (and the related
> https://reviews.llvm.org/D22675 is also needed for correctness, though
> probably not for fixing the hang).

FYI, I've reverted the revert.

Marek