rs6000.md (strlensi): Don't use subsi3 with a constant, use addsi3 directly.

rs6000.md (strlensi): Don't use subsi3 with a constant, use addsi3 directly.

2014-09-21  Segher Boessenkool  <segher@kernel.crashing.org>

	* config/rs6000/rs6000.md (strlensi): Don't use subsi3 with a
	constant, use addsi3 directly.
	(three anonymous define_insn, two define_split): Delete.
	(sub<mode>3): Move.  Do not allow constant second operand.
	Generate different insn for constant first operand.
	(*subf<mode>3, *subf<mode>3_dot, *subf<mode>3_dot2): New.
	(subf<mode>3_imm): New.
	(ctz<mode>2, ffs<mode>2): Clobber CA_REGNO where required.
	(*plus_ltu<mode>): Only handle registers.
	(*plus_ltu<mode>_1): New.  Handle integer third operand.
	(*plus_gtu<mode>): Only handle registers.
	(*plus_gtu<mode>_1): New.  Handle integer third operand.

From-SVN: r215434