https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120194
--- Comment #3 from Tobias Burnus <burnus at gcc dot gnu.org> --- > ... this is ill-formed OpenMP? For 'requires unified_shared_memory', you are in the realm of un(der)specified behavior as OpenMP does not even mention how this case is handled. If you do (A) - or (B.1) + (B.2) - you are on the safe side. [I think; having 'map' clauses while the library otherwise assumes shared memory might have some corner-case issues.] (A) also works without USM (ignoring pointer members) while (B) means that host and device data are always in sync. * * * Note that for 'self_maps' the following applies: "all corresponding list items created by the 'enter' clauses specified by 'declare target' directives in the compilation unit share storage with the original list items." [I note that this doesn't talk about the 'link' clause, though.] While GCC supports 'self_maps' since GCC 15, this feature subfeature is not yet implemented and on my to-do list for GCC 16. The idea is to implement it as (B.1) [i.e. turn 'enter' to 'link'] plus (B.2) - but simply setting all 'link' pointers by the host pointer. For 'unified_shared_memory' (B.2) is probably useful as well, but regarding 'enter' → 'link' I am not sure.
