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

[Nicolai Hähnle]

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?

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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