* i386.c (ix86_fp_comparison_arithmetics_cost,

	* i386.c (ix86_fp_comparison_arithmetics_cost,
	ix86_fp_comparison_fcomi_cost, ix86_fp_comparison_sahf_cost,
	ix86_fp_comparison_cost): New functions.
	(ix86_expand_fp_compare): Use the costs to choose best bethod; add
	two new parameters SECOND_TEST and BYPASS_TEST; allow generating
	two-branch sequences; make static.
	(ix86_use_fcomi_compare): Do decision according to the costs.
	(split_fp_branch): New.
	* i386.md (compare-and-branch patterns): Use split_fp_branch.
	* i386-protos.h (ix86_expand_fp_compare): Remove
	(ix86_split_fp_branch): Declare.

	* i386.h (PREDICATE_CODES): Update codes from fcmov_comparison_operand
	and ix86_comparison_operator.

	* i386.c (ix86_prepare_fp_compare_args): Try to rearange the comparison
	to make it cheaper.

	* i386.c (put_condition_code): Output properly the unordered/ordered
	compares in fp case.
	(ix86_expand_fp_movcc): Use ix86_expand_compare infrastructure.

	* tm.texi (REVERSE_CONDITION): Document.
	* i386.c (ix86_fp_compare_mode): Simplify; return always CCFPmode
	in -ffast-math mode.
	* i386.h (REVERSE_CONDITION, REVERSIBLE_CC_MODE): New macro.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@38979 138bc75d-0d04-0410-961f-82ee72b054a4