perf intel-pt: Move branch filter logic

intel_pt_synth_branch_sample() skips synthesizing if the branch does not
match the branch filter.  That logic was sitting in the middle of the
function but is more efficiently placed at the start of the function, so
move it.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1443186956-18718-14-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/intel-pt.c

@@ -891,6 +891,9 @@ static int intel_pt_synth_branch_sample(struct intel_pt_queue *ptq)
 	union perf_event *event = ptq->event_buf;
 	struct perf_sample sample = { .ip = 0, };
 
+	if (pt->branches_filter && !(pt->branches_filter & ptq->flags))
+		return 0;
+
 	event->sample.header.type = PERF_RECORD_SAMPLE;
 	event->sample.header.misc = PERF_RECORD_MISC_USER;
 	event->sample.header.size = sizeof(struct perf_event_header);
@@ -909,9 +912,6 @@ static int intel_pt_synth_branch_sample(struct intel_pt_queue *ptq)
 	sample.flags = ptq->flags;
 	sample.insn_len = ptq->insn_len;
 
-	if (pt->branches_filter && !(pt->branches_filter & ptq->flags))
-		return 0;
-
 	if (pt->synth_opts.inject) {
 		ret = intel_pt_inject_event(event, &sample,
 					    pt->branches_sample_type,