Implements vec_init when the input is a vector of smaller vectors, or of
vector MEM types, or a smaller vector duplicated several times.

gcc/ChangeLog:

	* config/gcn/gcn-valu.md (vec_init<V_ALL:mode><V_ALL_ALT:mode>): New.
	* config/gcn/gcn.cc (GEN_VN): Add andvNsi3, subvNsi3.
	(GEN_VNM): Add gathervNm_expr.
	(GEN_VN_NOEXEC): Add vec_seriesvNsi.
	(gcn_expand_vector_init): Add initialization of vectors from smaller
	vectors.
---
 gcc/config/gcn/gcn-valu.md |  10 +++
 gcc/config/gcn/gcn.cc      | 159 +++++++++++++++++++++++++++++++------
 2 files changed, 143 insertions(+), 26 deletions(-)