S/390: Get rid of Y constraint in arithmetic right shift

S/390: Get rid of Y constraint in arithmetic right shift
 patterns.

The arithmetic shift patterns set also the condition code.  This adds
more substitution potential.  Depending on whether the actual result
or the CC output will be used 3 different variants of each of these
patterns are needed.  This multiplied with the PLUS and the AND
operands from the earlier substitutions enables a lot of folding.

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

	* config/s390/s390.md ("*ashrdi3_cc_31")
	("*ashrdi3_cconly_31""*ashrdi3_cc_31_and")
	("*ashrdi3_cconly_31_and", "*ashrdi3_31_and", "*ashrdi3_31"):
	Merge insn definitions into ...
	("*ashrdi3_31<addr_style_op_cc><masked_op_cc><setcc><cconly>"):
	New pattern definition.
	("*ashr<mode>3_cc", "*ashr<mode>3_cconly", "ashr<mode>3", )
	("*ashr<mode>3_cc_and", "*ashr<mode>3_cconly_and")
	("*ashr<mode>3_and"): Merge insn definitions into ...
	("*ashr<mode>3<addr_style_op_cc><masked_op_cc><setcc><cconly>"):
	New pattern definition.
	* config/s390/subst.md ("addr_style_op_cc_subst")
	("masked_op_cc_subst", "setcc_subst", "cconly_subst"): New
	substitutions patterns plus attributes.
	Add ashiftrt to SUBST iterator.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@233845 138bc75d-0d04-0410-961f-82ee72b054a4