diff --git a/libavcodec/acelp_pitch_delay.c b/libavcodec/acelp_pitch_delay.c
index 6c5293ac8a..e488cc8eff 100644
--- a/libavcodec/acelp_pitch_delay.c
+++ b/libavcodec/acelp_pitch_delay.c
@@ -21,6 +21,7 @@
  */
 
 #include "libavutil/common.h"
+#include "libavutil/libm.h"
 #include "libavutil/mathematics.h"
 #include "avcodec.h"
 #include "dsputil.h"