AVX-512. 52.1/n. Add vec2mask and mask2vec insn.

AVX-512. 52.1/n. Add vec2mask and mask2vec insn.

gcc/
	* config/i386/predicates.md (define_predicate "constm1_operand"): New.
	* config/i386/sse.md
	(define_c_enum "unspec"): Add UNSPEC_CVTINT2MASK.
	(define_insn "<avx512>_cvt<ssemodesuffix>2mask<VI12_AVX512VL:mode>"): New.
	(define_insn "<avx512>_cvt<ssemodesuffix>2mask<VI48_AVX512VL:mode>"): Ditto.
	(define_expand "<avx512>_cvtmask2<ssemodesuffix><VI12_AVX512VL:mode>"): Ditto.
	(define_insn "*<avx512>_cvtmask2<ssemodesuffix><VI12_AVX512VL:mode>"): Ditto.
	(define_expand "<avx512>_cvtmask2<ssemodesuffix><VI48_AVX512VL:mode>"): Ditto.
	(define_insn "*<avx512>_cvtmask2<ssemodesuffix><VI48_AVX512VL:mode>"): Ditto.

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: r216254