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Diffstat (limited to 'llvm/docs/LangRef.rst')
| -rw-r--r-- | llvm/docs/LangRef.rst | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst index f98aa6270bb..0bac9e7c5f9 100644 --- a/llvm/docs/LangRef.rst +++ b/llvm/docs/LangRef.rst @@ -1493,6 +1493,16 @@ example: Annotated functions may still raise an exception, i.a., ``nounwind`` is not implied. If an invocation of an annotated function does not return control back to a point in the call stack, the behavior is undefined. +``nosync`` + This function attribute indicates that the function does not communicate + (synchronize) with another thread through memory or other well-defined means. + Synchronization is considered possible in the presence of `atomic` accesses + that enforce an order, thus not "unordered" and "monotonic", `volatile` accesses, + as well as `convergent` function calls. Note that through `convergent` function calls + non-memory communication, e.g., cross-lane operations, are possible and are also + considered synchronization. However `convergent` does not contradict `nosync`. + If an annotated function does ever synchronize with another thread, + the behavior is undefined. ``nounwind`` This function attribute indicates that the function never raises an exception. If the function does raise an exception, its runtime |
