[PATCH] D151997: [AMDGPU] Document amdgpu_cs_chain[_preserve] CCs. NFC

[Nicolai Hähnle via Phabricator via llvm-commits]

nhaehnle added inline comments.


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Comment at: llvm/docs/AMDGPUUsage.rst:1127
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+                                     Functions must be aligned to at least 64 bytes.
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arsenm wrote:
> nhaehnle wrote:
> > This shouldn't be a property of the calling convention. We should just set the alignment attribute in the frontend to ensure this.
> Why? Entry points require 256 byte align but regular code is fine with 4
Entry points require 256 for HW reasons. The 64 bytes we discussed is a SW choice that is orthogonal to the base functionality of amdgpu_cs_chain (making LSBs of function pointers available to stuff metadata in -- which we also could have considered doing with amdgpu_gfx functions).


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