Disable [[no_unique_address]] for mdspan and clang

We are experience data corruption when passing structs with nested `[[no_unique_address]]` to kernels. See nvbug4934171
NVIDIA · Oct 29, 2024 · e798687 · e798687
1 parent a237cc7
commit e798687
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/libcudacxx/include/cuda/std/__cccl/attributes.h b/libcudacxx/include/cuda/std/__cccl/attributes.h
@@ -67,6 +67,12 @@
 #  define _CCCL_NO_UNIQUE_ADDRESS
 #endif
 
+// Passing objects with nested [[no_unique_address]] to kernels leads to data corruption
+// This happens up to clang18
+#if defined(_CCCL_NO_UNIQUE_ADDRESS) && defined(_CCCL_COMPILER_CLANG)
+#  define _CCCL_HAS_NO_ATTRIBUTE_NO_UNIQUE_ADDRESS
+#endif // _CCCL_NO_UNIQUE_ADDRESS && _CCCL_COMPILER_CLANG
+
 #if _CCCL_HAS_CPP_ATTRIBUTE(nodiscard) || (defined(_CCCL_COMPILER_MSVC) && _CCCL_STD_VER >= 2017)
 #  define _CCCL_NODISCARD [[nodiscard]]
 #else // ^^^ has nodiscard ^^^ / vvv no nodiscard vvv