re PR tree-optimization/63341 (Vectorization miscompilation with -mcpu=power7)

re PR tree-optimization/63341 (Vectorization miscompilation with -mcpu=power7)

	PR tree-optimization/63341
	* tree-vectorizer.h (vect_create_data_ref_ptr,
	vect_create_addr_base_for_vector_ref): Add another tree argument
	defaulting to NULL_TREE.
	* tree-vect-data-refs.c (vect_create_data_ref_ptr): Add byte_offset
	argument, pass it down to vect_create_addr_base_for_vector_ref.
	(vect_create_addr_base_for_vector_ref): Add byte_offset argument,
	add that to base_offset too if non-NULL.
	* tree-vect-stmts.c (vectorizable_load): Add byte_offset variable,
	for dr_explicit_realign_optimized set it to vector byte size
	- 1 instead of setting offset, pass byte_offset down to
	vect_create_data_ref_ptr.

	* gcc.dg/vect/pr63341-1.c: New test.
	* gcc.dg/vect/pr63341-2.c: New test.

From-SVN: r215583