aarch64: Add support for unpacked SVE FP unary operations

aarch64: Add support for unpacked SVE FP unary operations

This patch extends the expander for unpredicated round, nearbyint, floor,
ceil, rint, and trunc, so that it can handle partial SVE FP modes.

We move fabs and fneg to a separate expander, since they are not trapping
instructions.

gcc/ChangeLog:

	* config/aarch64/aarch64-sve.md (<optab><mode>2): Replace use of
	aarch64_ptrue_reg with aarch64_sve_fp_pred.
	(@aarch64_pred_<optab><mode>): Extend from SVE_FULL_F to SVE_F,
	and use aarch64_predicate_operand.
	* config/aarch64/iterators.md: Split FABS/FNEG out of
	SVE_COND_FP_UNARY (into new SVE_COND_FP_UNARY_BITWISE).

gcc/testsuite/ChangeLog:

	* gcc.target/aarch64/sve/unpacked_fabs_1.c: New test.
	* gcc.target/aarch64/sve/unpacked_fneg_1.c: Likewise.
	* gcc.target/aarch64/sve/unpacked_frinta_1.c: Likewise.
	* gcc.target/aarch64/sve/unpacked_frinta_2.c: Likewise.
	* gcc.target/aarch64/sve/unpacked_frinti_1.c: Likewise.
	* gcc.target/aarch64/sve/unpacked_frinti_2.c: Likewise.
	* gcc.target/aarch64/sve/unpacked_frintm_1.c: Likewise.
	* gcc.target/aarch64/sve/unpacked_frintm_2.c: Likewise.
	* gcc.target/aarch64/sve/unpacked_frintp_1.c: Likewise.
	* gcc.target/aarch64/sve/unpacked_frintp_2.c: Likewise.
	* gcc.target/aarch64/sve/unpacked_frintx_1.c: Likewise.
	* gcc.target/aarch64/sve/unpacked_frintx_2.c: Likewise.
	* gcc.target/aarch64/sve/unpacked_frintz_1.c: Likewise.
	* gcc.target/aarch64/sve/unpacked_frintz_2.c: Likewise.