https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114282
Bug ID: 114282
Summary: [OpenMP] Implicit mapping of function/procedure
pointers should use 'firstprivate'
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Keywords: missed-optimization, openmp
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: burnus at gcc dot gnu.org
Target Milestone: ---
For C/C++ function pointers and Fortran dummy procedures / procedure pointers,
the assumption is that pointer is either pointing to the desired function
or it has the address of a function on the initial device with 'declare target
indirect'.
GCC produces for implicit mapping:
map(alloc:MEM[(char *)g] [len: 0]) map(firstprivate:g [pointer assign, bias:
0])
But a simple
map(firstprivate:g)
would do here.
Likewise for an explicit map, where there is also no need for a pointer
assignment.
NOTE: For Fortran, it might be that explicit 'map' clauses will get disallowed
per pending OpenMP specification Issue #3823, which is tracked elsewhere.
Trivial testcases (for more complex, see 'indirect' testcases inside GCC or
just add an explicit 'map' clause yourself):
void f(){
void (*g)();
#pragma omp target
g();
}
subroutine f(g)
procedure(), pointer :: g
!$omp target map(g)
call g()
!$omp end target
end
