rs6000: New insns setbc and setbcr

rs6000: New insns setbc and setbcr

New instructions setbc and setbcr.  setbc sets a GPR to 1 if some
condition register bit is set, and 0 otherwise; setbcr does it the
other way around.

2020-05-07  Segher Boessenkool  <segher@kernel.crashing.org>

	* config/rs6000/rs6000.md (setbc_<un>signed_<GPR:mode>): New
	define_insn.
	(*setbcr_<un>signed_<GPR:mode>): Likewise.
	(cstore<mode>4): Use setbc[r] if available.
	(<code><GPR:mode><GPR2:mode>2_isel): Avoid for TARGET_FUTURE.
	(eq<mode>3): Use setbc for TARGET_FUTURE.
	(*eq<mode>3): Avoid for TARGET_FUTURE.
	(ne<mode>3): Replace :P with :GPR; use setbc for TARGET_FUTURE;
	else for non-Pmode, use gen_eq and gen_xor.
	(*ne<mode>3): Avoid for TARGET_FUTURE.
	(*eqsi3_ext<mode>): Avoid for TARGET_FUTURE; fix missing && 1.