re PR tree-optimization/66510 (gcc.target/arm/pr53636.c FAILs after r224221)

re PR tree-optimization/66510 (gcc.target/arm/pr53636.c FAILs after r224221)

2015-06-18  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/66510
	* tree-vect-stmts.c (vectorizable_load): Properly compute the
	number of vector loads for SLP permuted loads.
	* tree-vect-data-refs.c (vect_compute_data_ref_alignment): Also
	check the stride for loop vectorization.
	(vect_enhance_data_refs_alignment): Deal with SLP adjusted
	vectorization factor.
	(vect_analyze_group_access): If the group size is not a power
	of two require a epilogue loop.
	* tree-vect-loop.c (vect_analyze_loop_2): Move alignment
	compute and optimizing and alias test pruning after final
	vectorization factor computation.
	* tree-vect-slp.c (vect_build_slp_tree_1): Remove check on
	vector alignment.
	(vect_transform_slp_perm_load): Properly compute the original
	number of vector load stmts.

	* gcc.dg/vect/slp-perm-12.c: New testcase.

From-SVN: r224598