[PATCH] D62574: Initial draft of target-configurable address spaces.

Fri Jun 7 08:00:41 PDT 2019

ebevhan added a comment.

>> I'll have to see if that's possible without breaking a few more interfaces, since you can throw around Qualifiers and check for compatibility without an ASTContext today.
>> 
>>> I was just thinking about testing the new logic. Should we add something like  `-ffake-address-space-map` (https://clang.llvm.org/docs/UsersManual.html#opencl-specific-options) that will force targets to use some implementation of fake address space conversions? It was quite useful in OpenCL before we added concrete targets with address spaces. Alternatively, we can try to use SPIR that is a generic Clang-only target that has address spaces.
>> 
>> Well, there are a couple targets which have target address spaces even today, I think. AMDGPU should be one, right?
> 
> Yes, however I am not sure we will be able to test more than what we test with OpenCL. Also I am not sure AMD maintainer would be ok. Do you have any concrete idea of what to test?

Well, since there is a mapping from the OpenCL address spaces to the AMDGPU target spaces, I would presume that if the target spaces were used on their own (via `__attribute__((address_space(1)))` for example) they should behave similarly to their OpenCL counterparts. It wouldn't have to be much, just a couple of type definitions and checks for implicit/explicit cast behavior.

There's also the x86 case I mentioned. I'm not really sure how that feature is used, though.

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https://reviews.llvm.org/D62574