re PR target/80846 (auto-vectorized AVX2 horizontal sum should narrow to 128b right...

re PR target/80846 (auto-vectorized AVX2 horizontal sum should narrow to 128b right away, to be more efficient for Ryzen and Intel)

	PR target/80846
	* config/i386/i386.c (ix86_expand_vector_init_general): Handle
	V2TImode and V4TImode.
	(ix86_expand_vector_extract): Likewise.
	* config/i386/sse.md (VMOVE): Enable V4TImode even for just
	TARGET_AVX512F, instead of only for TARGET_AVX512BW.
	(ssescalarmode): Handle V4TImode and V2TImode.
	(VEC_EXTRACT_MODE): Add V4TImode and V2TImode.
	(*vec_extractv2ti, *vec_extractv4ti): New insns.
	(VEXTRACTI128_MODE): New mode iterator.
	(splitter for *vec_extractv?ti first element): New.
	(VEC_INIT_MODE): New mode iterator.
	(vec_init<mode>): Consolidate 3 expanders into one using
	VEC_INIT_MODE mode iterator.

	* gcc.target/i386/avx-pr80846.c: New test.
	* gcc.target/i386/avx2-pr80846.c: New test.
	* gcc.target/i386/avx512f-pr80846.c: New test.

From-SVN: r250397