[Mesa-dev] [PATCH] radeonsi: disable sinking common instructions down to the end block

[Samuel Pitoiset]

On 03/23/2017 12:38 PM, Nicolai Hähnle wrote:
> On 22.03.2017 21:00, Andy Furniss wrote:
>> Samuel Pitoiset wrote:
>>
>> This patch has a minor issue for me using radeonsi on tonga.
>>
>> ffmpeg vaapi hwdecode by cli or via mpv now produces the message
>>
>> mesa: for the -simplifycfg-sink-common option: may only occur zero or
>> one times!
>
> I guess that setup ends up loading both radeonsi_dri.so and
> radeonsi_drv_video.so, and so the command line is set twice despite the
> use of a once_flag. Any ideas?

Yeah, that's probably why the message is displayed.

>
> Cheers,
> Nicolai
>
>>
>>>
>>> On 03/15/2017 02:01 PM, Marek Olšák wrote:
>>>> On Wed, Mar 15, 2017 at 1:56 PM, Samuel Pitoiset
>>>> <samuel.pitoiset at gmail.com> wrote:
>>>>>
>>>>>
>>>>> On 03/15/2017 01:51 PM, Marek Olšák wrote:
>>>>>>
>>>>>> On Wed, Mar 15, 2017 at 1:21 AM, Samuel Pitoiset
>>>>>> <samuel.pitoiset at gmail.com> wrote:
>>>>>>>
>>>>>>> Initially this was a workaround for a bug introduced in LLVM 4.0
>>>>>>> in the SimplifyCFG pass that caused image instrinsics to disappear
>>>>>>> (because they were badly sunk). Finally, this is a win because it
>>>>>>> decreases SGPR spilling and increases the number of waves a bit.
>>>>>>>
>>>>>>> Although, shader-db results are good I think we might want to
>>>>>>> remove it in the future once the issue is fixed. For now, enable
>>>>>>> it for LLVM >= 4.0.
>>>>>>>
>>>>>>> This also fixes a rendering issue with the speedometer in Dirt
>>>>>>> Rally.
>>>>>>>
>>>>>>> More information can be found here https://reviews.llvm.org/D26348.
>>>>>>>
>>>>>>> Thanks to Dave Airlie for the patch.
>>>>>>>
>>>>>>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99484
>>>>>>> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
>>>>>>> ---
>>>>>>>
>>>>>>> For those interested, here's the full shader-db report:
>>>>>>>
>>>>>>> https://hastebin.com/osepehehat.pas
>>>>>>>
>>>>>>>  src/gallium/drivers/radeonsi/si_shader_tgsi_setup.c | 6 ++++++
>>>>>>>  1 file changed, 6 insertions(+)
>>>>>>>
>>>>>>> diff --git a/src/gallium/drivers/radeonsi/si_shader_tgsi_setup.c
>>>>>>> b/src/gallium/drivers/radeonsi/si_shader_tgsi_setup.c
>>>>>>> index 5c63b732b3..4fb7a126e4 100644
>>>>>>> --- a/src/gallium/drivers/radeonsi/si_shader_tgsi_setup.c
>>>>>>> +++ b/src/gallium/drivers/radeonsi/si_shader_tgsi_setup.c
>>>>>>> @@ -40,6 +40,7 @@
>>>>>>>  #include <stdio.h>
>>>>>>>  #include <llvm-c/Transforms/IPO.h>
>>>>>>>  #include <llvm-c/Transforms/Scalar.h>
>>>>>>> +#include <llvm-c/Support.h>
>>>>>>>
>>>>>>>  /* Data for if/else/endif and bgnloop/endloop control flow
>>>>>>> structures.
>>>>>>>   */
>>>>>>> @@ -124,6 +125,11 @@ static void init_amdgpu_target()
>>>>>>>         LLVMInitializeAMDGPUTarget();
>>>>>>>         LLVMInitializeAMDGPUTargetMC();
>>>>>>>         LLVMInitializeAMDGPUAsmPrinter();
>>>>>>> +
>>>>>>> +#if HAVE_LLVM >= 0x0400
>>>>>>> +       const char *argv[2] = {"mesa",
>>>>>>> "-simplifycfg-sink-common=false"};
>>>>>>> +       LLVMParseCommandLineOptions(2, argv, NULL);
>>>>>>> +#endif
>>>>>>
>>>>>>
>>>>>> Would it possible to do:
>>>>>> if (HAVE_LLVM >= 0x0400) {
>>>>>> ...
>>>>>> }
>>>>>>
>>>>>> Also, Cc stable?
>>>>>
>>>>>
>>>>> Your call. But if the issue is fixed at some point in 4.0.1 or 5.0 we
>>>>> will
>>>>> need to backport one more patch.
>>>>
>>>> Since this only disables the problematic optimization, we can keep it
>>>> in stable and we won't have to backport anything else. (optimizations
>>>> are usually not accepted in stable)
>>>
>>> Fine by me. I will add the cc tag and the FIXME comment before pushing.
>>> Thanks.
>>>
>>>>
>>>> Marek
>>>>
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>>
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>
>