Protect loops that might be executed zero times.

2009-11-23  Tobias Grosser  <grosser@fim.uni-passau.de>

	PR middle-end/42130
	* graphite-clast-to-gimple.c (graphite_create_new_loop_guard,
	translate_clast_for_loop): New.
	(translate_clast_for): Add a condition around the loop, to do not
	execute loops with zero iterations.
	* testsuite/g++.dg/graphite/pr42130.C: New.
	* testsuite/gcc.dg/graphite/pr35356-2.c: Adapt.

From-SVN: r154849