pa.c (pa_adjust_insn_length): Rewrite so that it only adjusts insns which really need adjustment.

        * pa.c (pa_adjust_insn_length): Rewrite so that it only adjusts
        insns which really need adjustment.
        (output_cbranch): Rework so that output templates are simpler.
        Use shorter sequence for long backwards conditional branches with
        a filled delay slot that is nullified.  More agressively use "skip"
        instructions.  More agressively nullify the delay slot if nothing
        useful could be placed there.
        (output_bb): Likewise.
	(forward_branch_p): New function.

From-SVN: r4875