backport: sync.md: New file.

	Merge from gomp-branch.
	* config/sparc/sync.md: New file.
	* config/sparc/sparc.md (UNSPECV_MEMBAR, UNSPECV_CAS, UNSPECV_SWAP,
	UNSPECV_LDSTUB): New constants.
	* config/sparc/sparc.c (sparc_expand_compare_and_swap_12): New function.
	* config/sparc/predicates.md (memory_reg_operand): New predicate.
	* config/sparc/sparc-protos.h (sparc_expand_compare_and_swap_12): New
	prototype.

	* gcc.dg/ia64-sync-1.c: On sparc*-*-*, pass -mcpu=v9.
	* gcc.dg/ia64-sync-2.c: Likewise.
	* gcc.dg/ia64-sync-3.c: Likewise.
	* gcc.dg/ia64-sync-4.c: Likewise.
	* gcc.dg/sync-2.c: Likewise.
	* lib/target-supports.exp (sync_char_short, sync_int_long): Indicate
	that sparc64-*-* and sparcv9-*-* supports sync builtins.

From-SVN: r109271