tree-vect-stmts.c (vectorizable_load): Properly start loads with the first element if this is grouped loads.

2015-06-16  Richard Biener  <rguenther@suse.de>

	* tree-vect-stmts.c (vectorizable_load): Properly start loads
	with the first element if this is grouped loads.

	* gcc.dg/vect/slp-perm-11.c: New testcase.

From-SVN: r224511