i386: Implement V2SI and V4HI shuffles

i386: Implement V2SI and V4HI shuffles

2020-05-26  Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:
	* config/i386/mmx.md (*mmx_pshufd_1): New insn pattern.
	* config/i386/i386-expand.c (ix86_vectorize_vec_perm_const):
	Handle E_V2SImode and E_V4HImode.
	(expand_vec_perm_even_odd_1): Handle E_V4HImode.
	Assert that E_V2SImode is already handled.
	(expand_vec_perm_broadcast_1): Assert that E_V2SImode
	is already handled by standard shuffle patterns.

gcc/testsuite/ChangeLog:
	* gcc.target/i386/vperm-v2si.c: New test.
	* gcc.target/i386/vperm-v4hi.c: Ditto.