perf stat: Move target check to loop control statement

Check for target existence in loop control statement jointly external
asynchronous 'done' signal.
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/79037528-578c-af64-f06c-a644b7f5ba6a@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-stat.c

@@ -815,10 +815,8 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
 			psignal(WTERMSIG(status), argv[0]);
 	} else {
 		enable_counters();
-		while (!done) {
+		while (!done && is_target_alive(&target, evsel_list->core.threads)) {
 			nanosleep(&ts, NULL);
-			if (!is_target_alive(&target, evsel_list->core.threads))
-				break;
 			if (timeout || handle_interval(interval, &times))
 				break;
 		}