This patch switches most build_vector calls over to tree_vector_builder,
using explicit encodings where appropriate.  Later patches handle
the remaining uses of build_vector.

2017-12-07  Richard Sandiford  <richard.sandiford@linaro.org>

gcc/
	* config/sparc/sparc.c: Include tree-vector-builder.h.
	(sparc_fold_builtin): Use tree_vector_builder instead of build_vector.
	* expmed.c: Include tree-vector-builder.h.
	(make_tree): Use tree_vector_builder instead of build_vector.
	* fold-const.c: Include tree-vector-builder.h.
	(const_binop): Use tree_vector_builder instead of build_vector.
	(const_unop): Likewise.
	(native_interpret_vector): Likewise.
	(fold_vec_perm): Likewise.
	(fold_ternary_loc): Likewise.
	* gimple-fold.c: Include tree-vector-builder.h.
	(gimple_fold_stmt_to_constant_1): Use tree_vector_builder instead
	of build_vector.
	* tree-ssa-forwprop.c: Include tree-vector-builder.h.
	(simplify_vector_constructor): Use tree_vector_builder instead
	of build_vector.
	* tree-vect-generic.c: Include tree-vector-builder.h.
	(add_rshift): Use tree_vector_builder instead of build_vector.
	(expand_vector_divmod): Likewise.
	(optimize_vector_constructor): Likewise.
	* tree-vect-loop.c: Include tree-vector-builder.h.
	(vect_create_epilog_for_reduction): Use tree_vector_builder instead
	of build_vector.  Explicitly use a stepped encoding for
	{ 1, 2, 3, ... }.
	* tree-vect-slp.c: Include tree-vector-builder.h.
	(vect_get_constant_vectors): Use tree_vector_builder instead
	of build_vector.
	(vect_transform_slp_perm_load): Likewise.
	(vect_schedule_slp_instance): Likewise.
	* tree-vect-stmts.c: Include tree-vector-builder.h.
	(vectorizable_bswap): Use tree_vector_builder instead of build_vector.
	(vect_gen_perm_mask_any): Likewise.
	(vectorizable_call): Likewise.  Explicitly use a stepped encoding.
	* tree.c: (build_vector_from_ctor): Use tree_vector_builder instead
	of build_vector.
	(build_vector_from_val): Likewise.  Explicitly use a duplicate
	encoding.

From-SVN: r255475