Fix non-comforming expander for floatv2div2sf2,floatunsv2div2sf2,fix_truncv2sfv2di...

Fix non-comforming expander for floatv2div2sf2,floatunsv2div2sf2,fix_truncv2sfv2di,fixuns_truncv2sfv2di.

2020-05-26  Hongtao Liu  <hongtao.liu@intel.com>
	    Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:
	PR target/95211
	PR target/95256
	* config/i386/sse.md (<floatunssuffix>v2div2sf2): New expander.
	(fix<fixunssuffix>_truncv2sfv2di2): Ditto.
	(avx512dq_float<floatunssuffix>v2div2sf2): Renaming from
	float<floatunssuffix>v2div2sf2.
	(avx512dq_fix<fixunssuffix>_truncv2sfv2di2<mask_name>):
	Renaming from fix<fixunssuffix>_truncv2sfv2di2<mask_name>.
	(vec_pack<floatprefix>_float_<mode>): Adjust icode name.
	(vec_unpack_<fixprefix>fix_trunc_lo_<mode>): Ditto.
	(vec_unpack_<fixprefix>fix_trunc_hi_<mode>): Ditto.
	* config/i386/i386-builtin.def: Ditto.
	* emit-rtl.c (validate_subreg): Allow use of *paradoxical* vector
	subregs when both omode and imode are vector mode and
	have the same inner mode.

gcc/testsuite/ChangeLog
	* gcc.target/i386/pr95211.c: New test.