diff --git a/bitpack.c b/bitpack.c
index 43d3c0e..e1508c2 100755
--- a/bitpack.c
+++ b/bitpack.c
@@ -351,6 +351,7 @@ size_t bitnfpack128v32( uint32_t *__restrict in, size_t n, unsigned char *__rest
 
 #if defined(__AVX2__) && defined(AVX2_ON)
 #include <immintrin.h>
+#include "bitpack_.h"
 
 #define OPPE(__op)
 #define IPPE(__op)