add recursion on the inner loops

add recursion on the inner loops

We now check that all data references in the current loop and inner loops
contained within loop are valid in an outer region before declaring that the
outer loop is a valid scop.

2015-09-30  Sebastian Pop  <s.pop@samsung.com>
	    Aditya Kumar  <aditya.k7@samsung.com>

	PR tree-optimization/67754
	* graphite-scop-detection.c (loop_body_is_valid_scop): Add missing
	recursion on the inner loops.

Co-Authored-By: Aditya Kumar <aditya.k7@samsung.com>
From-SVN: r228346