[ARC] Add support for atomic memory built-in.

[ARC] Add support for atomic memory built-in.

gcc/

2015-12-10  Claudiu Zissulescu  <claziss@synopsys.com>

	* config/arc/arc-protos.h (arc_expand_atomic_op): Prototype.
	(arc_split_compare_and_swap): Likewise.
	(arc_expand_compare_and_swap): Likewise.
	* config/arc/arc.c (arc_init): Check usage atomic option.
	(arc_pre_atomic_barrier): New function.
	(arc_post_atomic_barrier): Likewise.
	(emit_unlikely_jump): Likewise.
	(arc_expand_compare_and_swap_qh): Likewise.
	(arc_expand_compare_and_swap): Likewise.
	(arc_split_compare_and_swap): Likewise.
	(arc_expand_atomic_op): Likewise.
	* config/arc/arc.h (TARGET_CPU_CPP_BUILTINS): New C macro.
	(ASM_SPEC): Enable mlock option when matomic is used.
	* config/arc/arc.md (UNSPEC_ARC_MEMBAR): Define.
	(VUNSPEC_ARC_CAS): Likewise.
	(VUNSPEC_ARC_LL): Likewise.
	(VUNSPEC_ARC_SC): Likewise.
	(VUNSPEC_ARC_EX): Likewise.
	* config/arc/arc.opt (matomic): New option.
	* config/arc/constraints.md (ATO): New constraint.
	* config/arc/predicates.md (mem_noofs_operand): New predicate.
	* doc/invoke.texi: Document -matomic.
	* config/arc/atomic.md: New file.

gcc/testsuite

2015-12-10  Claudiu Zissulescu  <claziss@synopsys.com>

	* lib/target-supports.exp (check_effective_target_arc_atomic): New
	function.
	(check_effective_target_sync_int_long): Add checks for ARC atomic
	feature.
	(check_effective_target_sync_char_short): Likewise.

From-SVN: r231509