re PR tree-optimization/29330 (-O -ftree-loop-linear --> virtual memory exhausted)

re PR tree-optimization/29330 (-O -ftree-loop-linear   -->  virtual memory exhausted)

	PR tree-optimization/29330
	* tree-data-ref.c (free_data_ref): Use DR_FREE_ACCESS_FNS macro.
	(initialize_data_dependence_relation): Clear DDR_LOOP_NEST pointer
	on newly allocated ddrs.
	(find_loop_nest_1, find_loop_nest): Change LOOP_NEST to a pointer
	to VEC (loop_p, heap) pointer.
	(compute_data_dependences_for_loop): Adjust caller.
	(free_dependence_relations): Free DDR_LOOP_NEST.

	* tree-loop-linear.c (linear_transform_loops): Don't forget to
	free DEPENDENCE_RELATIONS and DATAREFS.

	* gcc.dg/pr29330.c: New test.

From-SVN: r117509