scheduler: replace split_parallel by split_scaled option
The split_parallel option was ill-conceived.
The condition split_parallel looked for was too specific
and the implementation was wrong. Part of this has been fixed
in
1b2fdb6 (schedule.c: split_parallel: avoid invalid memory accesses,
Mon Jan 30 15:23:18 2012 +0100), but the code could in principle
still produce an incorrect schedule because it didn't check the sizes
of the constant terms.
The new option essentially applies strip-mining and should therefore
be safe. In particular, it is applied when the linear parts of the
schedules have a non-trivial common divisor. The strip-mining is
then performed with respect to this common divisor.
Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>