Eliminate false DV warnings for predicated calls to noreturn functions.

Eliminate false DV warnings for predicated calls to noreturn functions.

	* calls.c (emit_call_1): Add REG_NORETURN note to call if ECF_NORETURN.
	* combine.c (distribute_notes): Handle REG_NORETURN.
	* rtl.c (reg_note_name): Add REG_NORETURN.
	* rtl.h (enum reg_note): Likewise.
	* config/ia64/ia64-protos.h (emit_safe_across_calls): Renamed from
	ia64_file_start.
	* config/ia64/ia64.c (emit_safe_across_calls): Likewise.
	(rtx_needs_barrier): Handle unspec_volatile 8 and 9.
	(emit_predicate_relation_info): Handle conditional calls with
	REG_NORETURN.
	* config/ia64/ia64.h (ASM_FILE_START): Call emit_safe_across_calls
	instead of ia64_file_start.
	* config/ia64/sysv4.h (ASM_FILE_START): Likewise.
	* config/ia64/ia64.md (safe_across_calls_all,
	save_across_calls_normal): New patterns.

From-SVN: r36107