https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90591
Bug ID: 90591
Summary: Avoid unnecessary data transfer out of OMP construct
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Keywords: openacc, openmp
Severity: enhancement
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: tschwinge at gcc dot gnu.org
CC: jakub at gcc dot gnu.org
Target Milestone: ---
The reverse side of PR90573. For (all too common!) code like:
int i;
#pragma acc kernels // implicit 'copy(i)', or 'copyout(i)' with PR90573
{
for (i = 0; i < N; ++i)
[...]
}
#pragma acc kernels // implicit 'copy(i)', or 'copyout(i)' with PR90573
{
for (i = N - 1; i >= 0; --i)
[...]
}
['i' never read here]
In addition that we can avoid unnecessary data transfer into each OMP construct
(PR90573), we also don't need to copy 'i' out in such scenarios, so can
optimize 'copy' to 'copyin', or 'copyout' to 'create'.
