Hi,

The instruction "vec_pack_trunc_<mode>" should be split after register
allocator for scheduling reasons. Currently the instruction is marked as type
multiple which means it will scheduled as single issued. However, nothing can
be scheduled with either xtn/xtn2 which is a problem in some cases.

The patch splits the instruction and fixes the issue.

Please review the patch and let me know if its okay.
Bootstrapped and Regression tested on aarch64-thunder-linux.

2017-04-27  Naveen H.S  <Naveen.Hurugalawadi@cavium.com>

	* config/aarch64/aarch64-simd.md
	(aarch64_simd_vec_pack_trunc_hi_<mode>): New pattern.
	(vec_pack_trunc_<mode>): Split the instruction pattern.