Fix PR47653: do not handle loops using wrapping semantics in graphite

2011-07-26  Sebastian Pop  <sebastian.pop@amd.com>

	PR middle-end/47653
	* graphite-scop-detection.c (graphite_can_represent_loop): Discard
	loops using wrapping semantics.

	* gcc.dg/graphite/run-id-pr47653.c: New.
	* gcc.dg/graphite/interchange-3.c: Do not use unsigned types for
	induction variables.
	* gcc.dg/graphite/scop-16.c: Same.
	* gcc.dg/graphite/scop-17.c: Same.
	* gcc.dg/graphite/scop-21.c: Same.

From-SVN: r176802