[PATCH] D146031: [AMDGPU] Add MMOs for GFX11 Streamout Instructions

Thu Mar 16 03:48:49 PDT 2023

foad added inline comments.

================
Comment at: llvm/lib/Target/AMDGPU/AMDGPU.h:388

+    STREAMOUT_REGISTER = 8, ///< Address space for GS NGG Streamout registers.
+
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t-tye wrote:
> foad wrote:
> > Maybe add a comment here saying "the following address spaces are internal-only and can be freely renumbered"? E.g. @Pierre-vh plans to add a new user-visible address space 8, but I think it should be fine to do that by renumbering STREAMOUT_REGISTER to 9 to make room.
> > 
> > I am assuming we will end up with more internal-only address spaces similar to this one.
> Or could the internal address spaces start at a higher number so they do not have to be renumbered? AMDGPUUsage could then reserve a set of values to "internal use".
> I am assuming we will end up with more internal-only address spaces similar to this one.

For example we currently use a GWSResource PseudoSourceValue to represent GWS sync resources, and they end up in address space 0, which is just plain wrong. It would be better to use a dedicated internal-only address space for them, at which point the PSV no longer adds any value and we could get rid of it.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D146031/new/

https://reviews.llvm.org/D146031