i386: Cleanup comparison predicates.

i386: Cleanup comparison predicates.

CCCmode is allowed only with GEU and LTU comparison codes.  Also allow
CCGZmode for these two codes.  There is no need to check for trivial FP
comparison operator, ix86_fp_compare_code_to_integer will return
UNKNOWN code for unsupported operators.

2021-04-29  Uroš Bizjak  <ubizjak@gmail.com>

gcc/
	* config/i386/predicates.md (fcmov_comparison_operator):
	Do not check for trivial FP comparison operator.
	<case GEU, case LTU>: Allow CCGZmode.
	<case GTU, case LEU>: Do not allow CCCmode.
	(ix86_comparison_operator) <case GTU, case LEU>: Allow only CCmode.
	(ix86_carry_flag_operator): Match only LTU and UNLT code.
	Do not check for trivial FP comparison operator.  Allow CCGZmode.