isl_map_is_disjoint: maps with non-matching tuples may still intersect

isl_map_is_disjoint: maps with non-matching tuples may still intersect

isl_map_is_disjoint first calls isl_map_plain_is_disjoint to handle
some obvious cases, but if the parameters of the input maps have
not been aligned, then isl_map_plain_is_disjoint may come to the wrong
conclusion.  In particular, if the maps involve nested spaces, then
isl_space_match will return false, whereas isl_map_plain_is_disjoint
expects the function to return true.

We may have to reconsider isl_space_match at some point, but for now
we simply make sure that the parameters are the same before calling
isl_space_match on the input and output tuples.

Reported-by: Michael Kruse <meinersbur@googlemail.com>
Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>