This change is wrong, the different patch is landed in llvm to handle global address space access in gfx60x for HSA Os. So closing it.

Fixed a small typo in comments. Nothing else is changed from prior diff.

Included the suggestions given by tony.

If this is fine, place land. I don't have commit access yet.

added a blank line in amdgpuusage.rst file.

Updated the AMDGPUUsage doc. Also I don't have commit access, please commit this patch on my behalf.
Thanks a lot your time.

Updated the code according to scott's suggestion. And I tried to compile sample program with all possible combinations of processors and ABIs( amdhsa, mesa3d, amdpal), it seems like the backend supports all the ABIs for all processors. So Instead of adding a separate column, (since values of processors will be the same) I added a text pharse above the processor table which documents. Is it right thing to do so?

In D92483#2466144, @scott.linder wrote:

In D92483#2463773, @rampitec wrote:

In D92483#2463314, @pvellien wrote:

In 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?

In D92483#2458755, @rampitec wrote:

In D92483#2458659, @rampitec wrote:

In D92483#2458152, @pvellien wrote:

if mcpu is specified, set Gen to the correct generation that cpu belongs to, by initializing it with SOUTHERN_ISLANDS.
if mcpu is not specified (in this case GPU = "generic-hsa"), set Gen to the SEA_LANDS to be in parity with previous code> Comments inline

You are forcing SI for any SPECIFIED GPU instead:

!GPU.contains("generic") ? SOUTHERN_ISLANDS

Read this code line: if CPU is NOT generic, force it to SI.

Ugh. I see what you mean now, it took debugger to understand. The real value of Gen is assigned below in the GCNSubtarget::initializeSubtargetDependencies().

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.

Comments inline

Removed error reporting based on string comparison. Updated the memory legalizer tests to include amdhsa for gfx60x

fixed a typo in comments.

Comments inline

Updated with stanislav comments