[PATCH] D69103: Backend for NEC SX-Aurora

[Renato Golin via Phabricator via llvm-commits]

rengolin added a comment.

In D69103#1723824 <https://reviews.llvm.org/D69103#1723824>, @simoll wrote:

> Great! How do we mark the target to make it clear it's experimental?


There used to be different registers in CMake and some structs, I can't remember. There are some comments in here that may help, but ultimately, you want to make sure that your target is only built if explicitly named, so we don't break bots.

> How much of that do you need to see before this patch here can be approved? I am asking because as we are refactoring the out-of-tree patches for upstreaming, it'd ease the pain of rebasing if some of the changes outside of `lib/Target/VE` could already go in.

Ideally you'd like to at least show the next steps (in the order you named). This could be a tentative Phab review, or a branch on your Github repo that shows it, but it would have to end up in Phab in a way that can be merged pretty soon.

What we're trying to avoid here is to have a long period (potentially across releases) with just the stub in and no real code. The current patch is just a marker and it would be good to see you're on the right path early on, so make any strong refactory before starting the patch set.

> Beyond this patch, the critical changes are:
> 
> - TableGen:
>   - IntrinsicEmitter (Additional `IIT_Info` enum entries).
>   - CodeGenTarget (`MVT` enum entries).
> - Clang: VE toolchain.
> 
>   Later, we will add target-specific vector intrinsics to Clang and LLVM.

I'm also interested in how you're going to connect to the rest of the toolchain. Are you emitting direct binaries (are they ELF-like?) or assembly that gets lowered by a proprietary tool (like NVidia)?

Also, what is the subset of IR that can work in your target (if any) and will Clang be responsible for filtering it or do we barf in the middle-end?

I'm expecting the loop vectoriser to be of interest, because if all we have is intrinsics, than it's easier to write assembly directly. :)

--renato


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https://reviews.llvm.org/D69103