[clang] [llvm] [NVPTX] Add 'activemask' builtin and intrinsic support (PR #79768)

[Artem Belevich via cfe-commits]

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@@ -4599,6 +4599,14 @@ def int_nvvm_vote_ballot_sync :
             [IntrInaccessibleMemOnly, IntrConvergent, IntrNoCallback], "llvm.nvvm.vote.ballot.sync">,
   ClangBuiltin<"__nvvm_vote_ballot_sync">;
 
+//
+// ACTIVEMASK
+//
+def int_nvvm_activemask :
+  Intrinsic<[llvm_i32_ty], [],
+            [IntrInaccessibleMemOnly, IntrConvergent, IntrNoCallback, IntrHasSideEffects], "llvm.nvvm.activemask">,
+  ClangBuiltin<"__nvvm_activemask">;
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Artem-B wrote:

Separate patch is fine, too. 

https://github.com/llvm/llvm-project/pull/79768