https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93510
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |INVALID
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Ah, no, that translation is not faithful, the original testcase has undefined
behavior.
The a array has 1024 elements, with indexes 1 to 1024.
So, when you use:
DO x = 1, N, 16
DO y = 1, 16
... a(x + y)
END DO
END DO
it doesn't do what you expect it to do, it doesn't access elements 1 to 1024,
but 2 to 1025 and the a(1025) read is where the UB is invoked.
I guess you meant either to do:
DO x = 0, N - 1, 16
DO y = 1, 16
or
DO x = 1, N, 16
DO y = 0, 15
