[PATCH] D94429: AMDGPU: Move handling of allocation of fixed ABI inputs

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

In D94429#2492683 <https://reviews.llvm.org/D94429#2492683>, @Flakebi wrote:

>> Also stop passing them for amdgpu_gfx, since the DAG path seems to skip these. I'm unclear on what amdgpu_gfx's expectations are.
>
> As far as I understand, the “special inputs” are arguments relevant for HSA only and depending on `EnableFixedFunctionABI` they are added in the beginning or end of arguments.
> So, `passSpecialInputs` should be guarded by “is HSA” instead of “is not amdgpu_gfx”?

That breaks down for the other compute users too. Mesa/clover will also need most of the same inputs. Conversely, there are also inputs we don't try to handle which graphics may need (e.g. llvm.amdgcn.implicit.buffer.ptr, although I think that one is only needed in the entry point)

> I think we only want to pass the stack pointer into functions for our usage of amdgpu_gfx (and other implicit arguments like exec). All other arguments are added by the frontend.

At a minimum the common ABI should defined the SP and SRD location. We also should defined the FP/BP commonly although they aren't passed (which they are now, but I'm thinking about moving them)


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D94429/new/

https://reviews.llvm.org/D94429