[clang] [Clang][HIP][CUDA] Add `__cluster_dims__` and `__no_cluster__` attribute (PR #156686)

[Erich Keane via cfe-commits]

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@@ -13027,6 +13027,14 @@ def warn_cuda_maxclusterrank_sm_90 : Warning<
   "maxclusterrank requires sm_90 or higher, CUDA arch provided: %0, ignoring "
   "%1 attribute">, InGroup<IgnoredAttributes>;
 
+def err_cuda_cluster_attr_not_supported : Error<
+  "%select{__cluster_dims__|__no_cluster__}0 is not supported for this GPU architecture"
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erichkeane wrote:

Just use a `%0`, that way we can accept other spellings as well.

https://github.com/llvm/llvm-project/pull/156686