Clarify comments and use build_pddr.

Clarify comments and use build_pddr.

2010-01-20  Sebastian Pop  <sebastian.pop@amd.com>

	* graphite-dependences.c: Clarify comments.
	(build_pddr): Add an extra parameter direction.
	(graphite_legal_transform_dr): Use build_pddr.
	(dot_original_deps_stmt_1): Update use of build_pddr.
	(dot_transformed_deps_stmt_1): Same.
	(dot_original_deps): Same.
	(dot_transformed_deps): Same.

	* testsuite/gcc.dg/graphite/interchange-12.c: New.
	* gcc/testsuite/gcc.dg/graphite/block-7.c: New.

From-SVN: r156545