i386: Improve [QH]Imode rotates with masked shift count [PR99405]

i386: Improve [QH]Imode rotates with masked shift count [PR99405]

The following testcase shows that while we nicely optimize away the
useless and? of shift count before rotation for [SD]Imode rotates,
we don't do that for [QH]Imode.

The following patch optimizes that by using the right iterator on those
4 patterns.

2021-04-27  Jakub Jelinek  <jakub@redhat.com>

	PR target/99405
	* config/i386/i386.md (*<insn><mode>3_mask, *<insn><mode>3_mask_1):
	For any_rotate define_insn_split and following splitters, use
	SWI iterator instead of SWI48.

	* gcc.target/i386/pr99405.c: New test.