perf tools: Handle - and + in parsing trace print format

The opterators '-' and '+' are not handled in the trace print
format.

To do: '++' and '--'.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <20091014194400.330843045@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/util/trace-event-parse.c

@@ -2106,6 +2106,12 @@ static unsigned long long eval_num_arg(void *data, int size,
 				die("unknown op '%s'", arg->op.op);
 			val = left == right;
 			break;
+		case '-':
+			val = left - right;
+			break;
+		case '+':
+			val = left + right;
+			break;
 		default:
 			die("unknown op '%s'", arg->op.op);
 		}