S/390: Get rid of Y constraint in rotate patterns.

S/390: Get rid of Y constraint in rotate patterns.

This patch introduces substitution patterns to add PLUS const_int, and
AND operands to patterns and uses this to rewrite the existing rotate
pattern.

gcc/ChangeLog:

2016-03-01  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* config/s390/predicates.md (const_int_6bitset_operand): New
        predicates.
	* config/s390/s390.md: Include subst.md.
	("rotl<mode>3"): New expander.
	("rotl<mode>3", "*rotl<mode>3_and"): Merge insn definitions into
	...
	("*rotl<mode>3<addr_style_op><masked_op>"): New insn definition.
	* config/s390/subst.md: New file.

From-SVN: r233843