x86: Handle V8BF in expand_vec_perm_broadcast_1

x86: Handle V8BF in expand_vec_perm_broadcast_1

gcc/ChangeLog:

	PR target/106742
	* config/i386/i386-expand.cc (ix86_expand_vector_init_duplicate):
	Handle V8BF mode.
	(expand_vec_perm_broadcast_1): Ditto.
	* config/i386/sse.md (avx512fmaskhalfmode): Add BF vector mode.
	(vec_set<mode>_0): Add @ to it.
	(@vec_set<mode>_0): Ditto.
	(vec_interleave_high<mode><mask_name>): Ditto.
	(@vec_interleave_high<mode><mask_name>): Ditto.
	(vec_interleave_low<mode><mask_name>): Ditto.
	(@vec_interleave_low<mode><mask_name>): Ditto.
	* config/i386/subst.md (SUBST_V): Add BF vector mode.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/pr106742.c: New test.