rs6000: Update conditional jump patterns, no more (pc) (label_ref)

rs6000: Update conditional jump patterns, no more (pc) (label_ref)

Currently we have two patterns for every conditional jump: one jumping
if some condition is met, and the other jumping if it is not met.  We
don't need that second form because all our conditions have an opposite
already, and the generic code can deal with that just fine.

This patch deletes that second form.  We generated it directly in one
case; adjusted here.

	* config/rs6000/rs6000-string.c (expand_strncmp_align_check): Invert
	a conditional jump (and the compare for it) so that pc_rtx is the
	last operand.
	* config/rs6000/rs6000.c (rs6000_legitimate_combined_insn): Adjust
	for the deleted and renamed ctr<mode>_internal[234] patterns.
	* config/rs6000/rs6000.md: Delete second conditional branch pattern.
	Delete second conditional return pattern.
	(ctr<mode>_internal2): Delete this second bdnz pattern.
	(ctr<mode>_internal3): Rename to ctr<mode>_internal2.
	(ctr<mode>_internal4): Delete this second bdz pattern.

From-SVN: r253531