[AArch64] Use atomic load-operate instructions for fetch-update patterns.

[AArch64] Use atomic load-operate instructions for fetch-update patterns.

gcc/
2015-09-22  Matthew Wahab  <matthew.wahab@arm.com>

	* config/aarch64/aarch64-protos.h
	(aarch64_atomic_ldop_supported_p): Declare.
	* config/aarch64/aarch64.c (aarch64_atomic_ldop_supported_p): New.
	(enum aarch64_atomic_load_op_code): New.
	(aarch64_emit_atomic_load_op): New.
	(aarch64_gen_atomic_ldop): Update to support load-operate
	patterns.
	* config/aarch64/atomics.md (atomic_<atomic_optab><mode>): Change
	to an expander.
	(aarch64_atomic_<atomic_optab><mode>): New.
	(aarch64_atomic_<atomic_optab><mode>_lse): New.
	(atomic_fetch_<atomic_optab><mode>): Change to an expander.
	(aarch64_atomic_fetch_<atomic_optab><mode>): New.
	(aarch64_atomic_fetch_<atomic_optab><mode>_lse): New.

gcc/testsuite/
2015-09-22  Matthew Wahab  <matthew.wahab@arm.com>

	* gcc.target/aarch64/atomic-inst-ldadd.c: New.
	* gcc.target/aarch64/atomic-inst-ldlogic.c: New.

From-SVN: r228001