rs6000: Workaround for PR98092

rs6000: Workaround for PR98092

The bcdinvalid_<mode> RTL instruction uses the "unordered" comparison,
which cannot be used if we have -ffinite-math-only.  We really need
CCMODEs that describe what bits in a CR field are set by other insns
than just comparisons, but that is a lot more surgery, and it is stage 4
now.  This patch does a simple workaround.

2021-03-16  Segher Boessenkool  <segher@kernel.crashing.org>

	PR target/98092
	* config/rs6000/predicates.md (branch_comparison_operator): Allow
	ordered and unordered for CCFPmode, if flag_finite_math_only.

gcc/testsuite/
	PR target/98092
	* gcc.target/powerpc/pr98092.c: New.