i386: Implement 4-byte vector (V4QI/V2HI) constant permutations

i386: Implement 4-byte vector (V4QI/V2HI) constant permutations

2021-07-05  Uroš Bizjak  <ubizjak@gmail.com>

gcc/
	* config/i386/i386-expand.c (ix86_split_mmx_punpck):
	Handle V4QI and V2HI modes.
	(expand_vec_perm_blend): Allow 4-byte vector modes with TARGET_SSE4_1.
	Handle V4QI mode. Emit mmx_pblendvb32 for 4-byte modes.
	(expand_vec_perm_pshufb): Rewrite to use switch statemets.
	Handle 4-byte dual operands with TARGET_XOP and single operands
	with TARGET_SSSE3.  Emit mmx_ppermv32 for TARGET_XOP and
	mmx_pshufbv4qi3 for TARGET_SSSE3.
	(expand_vec_perm_pblendv): Allow 4-byte vector modes with TARGET_SSE4_1.
	(expand_vec_perm_interleave2): Allow 4-byte vector modes.
	(expand_vec_perm_pshufb2): Allow 4-byte vector modes with TARGET_SSSE3.
	(expand_vec_perm_even_odd_1): Handle V4QI mode.
	(expand_vec_perm_broadcast_1): Handle V4QI mode.
	(ix86_vectorize_vec_perm_const): Handle V4QI mode.
	* config/i386/mmx.md (mmx_ppermv32): New insn pattern.
	(mmx_pshufbv4qi3): Ditto.
	(*mmx_pblendw32): Ditto.
	(*mmx_pblendw64): Rename from *mmx_pblendw.
	(mmx_punpckhbw_low): New insn_and_split pattern.
	(mmx_punpcklbw_low): Ditto.