[AArch64] Add support for SVE CNOT

[AArch64] Add support for SVE CNOT

This patch adds support for predicated and unpredicated CNOT
(logical NOT on integers).  In RTL terms, this is a select between
1 and 0 in which the predicate is fed by a comparison with zero.

2019-08-14  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* config/aarch64/predicates.md (aarch64_simd_imm_one): New predicate.
	* config/aarch64/aarch64-sve.md (*cnot<mode>): New pattern.
	(*cond_cnot<mode>_2, *cond_cnot<mode>_any): Likewise.

gcc/testsuite/
	* gcc.target/aarch64/sve/cnot_1.c: New test.
	* gcc.target/aarch64/sve/cond_cnot_1.c: Likewise.
	* gcc.target/aarch64/sve/cond_cnot_1_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_cnot_2.c: Likewise.
	* gcc.target/aarch64/sve/cond_cnot_2_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_cnot_3.c: Likewise.
	* gcc.target/aarch64/sve/cond_cnot_3_run.c: Likewise.

From-SVN: r274438