decoder/mad, output_thread: add gcc_unlikely()

src/decoder/mad_decoder_plugin.c

@@ -76,9 +76,9 @@ mad_fixed_to_24_sample(mad_fixed_t sample)
 	sample = sample + (1L << (MAD_F_FRACBITS - bits));
 
 	/* clip */
-	if (sample > MAX)
+	if (gcc_unlikely(sample > MAX))
 		sample = MAX;
-	else if (sample < MIN)
+	else if (gcc_unlikely(sample < MIN))
 		sample = MIN;
 
 	/* quantize */

src/output_thread.c

@@ -435,7 +435,7 @@ ao_play_chunk(struct audio_output *ao, const struct music_chunk *chunk)
 	assert(ao != NULL);
 	assert(ao->filter != NULL);
 
-	if (chunk->tag != NULL) {
+	if (gcc_unlikely(chunk->tag != NULL)) {
 		g_mutex_unlock(ao->mutex);
 		ao_plugin_send_tag(ao, chunk->tag);
 		g_mutex_lock(ao->mutex);