AVX-512. Add byte/word plus/minus/avg.

AVX-512. Add byte/word plus/minus/avg.

gcc/
	(define_mode_iterator VI12_AVX2): Add V64QI and V32HI modes.
	(define_expand "<sse2_avx2>_<plusminus_insn><mode>3<mask_name>"): Add
	masking.
	(define_insn "*<sse2_avx2>_<plusminus_insn><mode>3<mask_name>"): Ditto.
	(define_expand "<sse2_avx2>_uavg<mode>3<mask_name>"): Ditto.
	(define_insn "*<sse2_avx2>_uavg<mode>3<mask_name>"): Ditto.
	(define_insn "*mul<mode>3"): Add EVEX version.

Co-Authored-By: Andrey Turetskiy <andrey.turetskiy@intel.com>
Co-Authored-By: Anna Tikhonova <anna.tikhonova@intel.com>
Co-Authored-By: Ilya Tocar <ilya.tocar@intel.com>
Co-Authored-By: Ilya Verbin <ilya.verbin@intel.com>
Co-Authored-By: Kirill Yukhin <kirill.yukhin@intel.com>
Co-Authored-By: Maxim Kuznetsov <maxim.kuznetsov@intel.com>
Co-Authored-By: Michael Zolotukhin <michael.v.zolotukhin@intel.com>
From-SVN: r214672