i386: Implement V2SF shuffles

i386: Implement V2SF shuffles

2020-05-27  Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:
	* config/i386/mmx.md (mmx_pswapdsf2): Add SSE alternatives.
	Enable insn pattern for TARGET_MMX_WITH_SSE.
	(*mmx_movshdup): New insn pattern.
	(*mmx_movsldup): Ditto.
	(*mmx_movss): Ditto.
	* config/i386/i386-expand.c (ix86_vectorize_vec_perm_const):
	Handle E_V2SFmode.
	(expand_vec_perm_movs): Handle E_V2SFmode.
	(expand_vec_perm_even_odd): Ditto.
	(expand_vec_perm_broadcast_1): Assert that E_V2SFmode
	is already handled by standard shuffle patterns.

gcc/testsuite/ChangeLog:
	* gcc.target/i386/vperm-v2sf.c: New test.