https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101602
--- Comment #3 from Michael Klemm <michael at dontknow dot de> --- The locality specifiers cannot directly map to the OpenMP data-sharing clauses. While SHARED and LOCAL can be mapped, LOCAL_INIT cannot. The latter needs to initialize the variable anew for each iteration of the DO CONCURRENT loop, while FIRSTPRIVATE will initialize the variable only once per thread that executes chunks of said loop. So, the code transformation for that case will have to be more involved. There has been discussions in the OpenMP language committee if a LINEAR(x:0) clause can substitute LOCAL_INIT(x). That might be one solution to reduce the implementation burden and map everything to OpenMP constructs.
