PR tree-optimization/37482
	* tree-vectorizer.h (struct _slp_instance): Add new field.
	(SLP_INSTANCE_FIRST_LOAD_STMT): New.
	(get_earlier_stmt): New function.
	* tree-vect-analyze.c (vect_find_first_load_in_slp_instance): New
	function.
	(vect_analyze_slp_instance): Set SLP_INSTANCE_FIRST_LOAD_STMT.
	* tree-vect-transform.c (vect_finish_stmt_generation): Remove the
	asserts that GSI points to the scalar statement being vectorized.
	Set new statement location according to GSI.
	(vect_schedule_slp_instance): Use GSI of
	SLP_INSTANCE_FIRST_LOAD_STMT when vectorizing loads.

From-SVN: r140544