https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87648
Bug ID: 87648
Summary: Clobber some variables on entry to DO CONCURRENT
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: tkoenig at gcc dot gnu.org
Target Milestone: ---
For variables which are defined in a DO CONCURRENT loop,
it should be beneficial to clobber them on entry.
This could have two benefits: Catching undefined variables for
constructs like
do concurrent (i = 1:size(a))
s = s + (2 * a(i) - 1)
end do
but not for things like
do concurrent (i = 1:size(a))
if (i == 42) s = (2 * a(i) - 1)
end do
and possibly as an aid to optimization.
For some analysis, see
https://groups.google.com/d/msg/comp.lang.fortran/ksGzUPK7GBM/ulfEBGFkBQAJ
