AVX512FP16: Add expander for fmahf4

gcc/ChangeLog:

	* config/i386/sse.md (FMAMODEM): extend to handle FP16.
	(VFH_SF_AVX512VL): Extend to handle HFmode.
	(VF_SF_AVX512VL): Deleted.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/avx512fp16-fma-1.c: New test.
	* gcc.target/i386/avx512fp16vl-fma-1.c: New test.
	* gcc.target/i386/avx512fp16vl-fma-vectorize-1.c: New test.
4 files changed