[AArch64] Merge SVE FP unary patterns

[AArch64] Merge SVE FP unary patterns

This patch merges the SVE FP rounding patterns with the other SVE
FP unary patterns.

At the moment, we only generate unary FP operations for full vectors,
so we can use (sqrt:VNx4SF ...) etc. in the rtl pattern.  With the ACLE,
it's also possible to generate predicated operations on partial vectors
without specifying a value for inactive lanes.  (sqrt:VNx4SF ...) would
then have different faulting behaviour from the instruction that the
pattern generates.

This patch therefore uses unspecs to represent the operations instead.
Later patches make this change for other patterns.

2019-08-07  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* config/aarch64/iterators.md (UNSPEC_COND_FABS, UNSPEC_COND_FNEG)
	(UNSPEC_COND_FRINTA, UNSPEC_COND_FRINTI, UNSPEC_COND_FRINTM)
	(UNSPEC_COND_FRINTN, UNSPEC_COND_FRINTP, UNSPEC_COND_FRINTX)
	(UNSPEC_COND_FRINTZ, UNSPEC_COND_FSQRT): New unspecs.
	(optab, sve_fp_op): Handle them.
	(SVE_FP_UNARY): Delete.
	(optab): Remove sqrt entry.
	(sve_fp_op): Remove neg, abs and sqrt entries.
	(SVE_COND_FP_UNARY): New int iterator.
	* config/aarch64/aarch64-sve.md (<frint_pattern><mode>2)
	(*<frint_pattern><mode>2): Delete.
	(<SVE_FP_UNARY:optab><SVE_F:mode>2): Replace with...
	(<SVE_COND_FP_UNARY:optab><SVE_F:mode>2): ...this.
	(*<SVE_FP_UNARY:optab><SVE_F:mode>2): Replace with...
	(*<SVE_COND_FP_UNARY:optab><SVE_F:mode>2): ...this.

From-SVN: r274187