If we don't HONOR_NANS we should not try to use any unordered
comparison results.  Best case those will just be optimized away;
realistically, they ICE.  For example, the rs6000 backend has some
code that specifically checks we never do this.


	PR tree-optimization/88055
	* tree-call-cdce.c (comparison_code_if_no_nans): New function.
	(gen_one_condition): Use it if !HONOR_NANS.

From-SVN: r270460