graphite-dependences.c (subtract_commutative_associative_deps): Add NULL checking...

graphite-dependences.c (subtract_commutative_associative_deps): Add NULL checking of the following variables...

	gcc/
	* graphite-dependences.c (subtract_commutative_associative_deps):
	Add NULL checking of the following variables: must_raw_no_source,
	may_raw_no_source, must_war_no_source, may_war_no_source,
	must_waw_no_source, may_waw_no_source, must_raw, may_raw,
	must_war, may_war, must_waw, may_waw

	gcc/testsuite/gfortran.dg/graphite/pr59586.f: New testcase.

From-SVN: r212122