This patch makes vect_get_vec_def_for_stmt_copy take a vec_info
rather than a vect_def_type.  If the vector operand passed in is
defined in the vectorised region, we should look for copies in
the normal way.  If it's defined in an external statement
(such as by vect_init_vector_1) we should just use the original value.

2018-07-31  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* tree-vectorizer.h (vect_get_vec_defs_for_stmt_copy)
	(vect_get_vec_def_for_stmt_copy): Take a vec_info rather than
	a vect_def_type for the first argument.
	* tree-vect-stmts.c (vect_get_vec_defs_for_stmt_copy): Likewise.
	(vect_get_vec_def_for_stmt_copy): Likewise.  Return the original
	operand if it isn't defined by a vectorized statement.
	(vect_build_gather_load_calls): Remove the mask_dt argument and
	update calls to vect_get_vec_def_for_stmt_copy.
	(vectorizable_bswap): Likewise the dt argument.
	(vectorizable_call): Update calls to vectorizable_bswap and
	vect_get_vec_def_for_stmt_copy.
	(vectorizable_simd_clone_call, vectorizable_assignment)
	(vectorizable_shift, vectorizable_operation, vectorizable_condition)
	(vectorizable_comparison): Update calls to
	vect_get_vec_def_for_stmt_copy.
	(vectorizable_store): Likewise.  Remove now-unnecessary calls to
	vect_is_simple_use.
	(vect_get_loop_based_defs): Remove dt argument and update call
	to vect_get_vec_def_for_stmt_copy.
	(vectorizable_conversion): Update calls to vect_get_loop_based_defs
	and vect_get_vec_def_for_stmt_copy.
	(vectorizable_load): Update calls to vect_build_gather_load_calls
	and vect_get_vec_def_for_stmt_copy.
	* tree-vect-loop.c (vect_create_epilog_for_reduction)
	(vectorizable_reduction, vectorizable_live_operation): Update calls
	to vect_get_vec_def_for_stmt_copy.

From-SVN: r263149