re PR tree-optimization/68379 (BB vectorization: definition in block 13 follows the use for SSA_NAME)

2015-12-01  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/68379
	* tree-vect-stmts.c (vectorizable_load): For BB vectorization
	always base loads on the first used DR of a group.
	* tree-vect-data-refs.c (vect_slp_analyze_and_verify_node_alignment):
	Compute alignment of the first scalar element unconditionally.

	* gcc.dg/torture/pr68379.c: New testcase.
	* gfortran.dg/pr68379-1.f90: Likewise.
	* gfortran.dg/pr68379-2.f: Likewise.

From-SVN: r231111