[PATCH] D92483: AMDGPU - Use MUBUF instructions for global address space access

[Stanislav Mekhanoshin via Phabricator via llvm-commits]

rampitec added a comment.

In D92483#2466144 <https://reviews.llvm.org/D92483#2466144>, @scott.linder wrote:

> In D92483#2463773 <https://reviews.llvm.org/D92483#2463773>, @rampitec wrote:
>
>> In D92483#2463314 <https://reviews.llvm.org/D92483#2463314>, @pvellien wrote:
>>
>>> In D92483#2458755 <https://reviews.llvm.org/D92483#2458755>, @rampitec wrote:
>>>
>>>> But I still do not think this is a right thing to do to accept amdhsa on SI, even if you turn off flat instructions. SI does not support HSA.
>>>
>>> As far as I the support of HSA in SI processors.  Tony suggested that gfx60x processors should support AMDHSA OS because it is capable of supporting OpenCL  1.2 which not need generic pointers. This topic was discussed in amdgcn weekly and using MUBUF instructions for global address space in gfx60x is decided. The same is also documented in AMDGPU User Guide earlier.
>>
>> But it is not. In fact AMDGPUUsage.rst says that SI does NOT support amdhsa and it is only supported starting from gfx700:
>>
>>   **GCN GFX6 (Southern Islands (SI))** [AMD-GCN-GFX6]_
>>   -----------------------------------------------------------------------------------------------------------------------
>>   ``gfx600``  - ``tahiti``    ``amdgcn``   dGPU                    - Does not      - *pal-amdpal*
>>                                                                      support
>>                                                                      generic
>>                                                                      address
>>                                                                      space
>>   ``gfx601``  - ``pitcairn``  ``amdgcn``   dGPU                    - Does not      - *pal-amdpal*
>>               - ``verde``                                            support
>>                                                                      generic
>>                                                                      address
>>                                                                      space
>>   ``gfx602``  - ``hainan``    ``amdgcn``   dGPU                    - Does not      - *pal-amdpal*
>>               - ``oland``                                            support
>>                                                                      generic
>>                                                                      address
>>                                                                      space
>>
>> It is only amdpal listed here.
>>
>> What was discussed is that we can use buffer instructions for global on SI even if amdhsa is not supported.
>
> At one point, while you were on vacation, the consensus was "support amdhsa OS with gfx6, and fail to compile in the presence of e.g. generic pointers".
>
> Has there been more discussion since then?

I see that is not what we document. @t-tye whatis your opinion?


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