llvm

6635e44d - [UR][Graph] Serialize submissions of the same command-buffer (#18295)

[UR][Graph] Serialize submissions of the same command-buffer (#18295) Update the UR command-buffer enqueue semantics such that command-buffer submissions are ordered with a dependency on previous submissions of the same command-buffer. That is the same semantic as we currently specify for executable graph objects in the SYCL-Graph extension. Allowing for a more efficient SYCL-RT implementation on top of UR where less UR events need to be created (future work). OpenCL is the only adapter that needs updated to provide these semantics, where we now track the `cl_event` returned from the most recent submission of a command-buffer, so that it can be used as a dependency of any future command-buffer submissions.