rs6000: Don't split FP comparisons at expand time

rs6000: Don't split FP comparisons at expand time

We currently expand various floating point comparisons early, to some
sequences with cror insns and the like.  This doesn't optimize well.

Change that to allow any of the 14 floating point comparisons in the
instruction stream, and split them after combine (at split1).

	* config/rs6000/predicates.md (extra_insn_branch_comparison_operator):
	New predicate.
	* config/rs6000/rs6000-protos.h (rs6000_emit_fp_cror): New declaration.
	* config/rs6000/rs6000.c (rs6000_generate_compare): Don't do anything
	special for FP comparisons that need a cror instruction eventually.
	(rs6000_emit_fp_cror): New function.
	(rs6000_emit_sCOND): Expand all floating point comparisons to one
	instruction, for normal FP modes, with HONOR_NANS.
	(rs6000_emit_cbranch): Reformat.
	* config/rs6000/rs6000.md (fp_rev): New iterator.
	(fp_two): New iterator.
	*<code><mode>_cc for fp_rev and GPR: New define_insn_and_split.
	*<code><mode>_cc for fp_two and GPR: New define_insn_and_split.
	*cbranch_2insn: New define_insn_and_split.

From-SVN: r278593