diff --git a/libavutil/fixed_dsp.c b/libavutil/fixed_dsp.c
index 8c018581df..f1b195f184 100644
--- a/libavutil/fixed_dsp.c
+++ b/libavutil/fixed_dsp.c
@@ -134,9 +134,10 @@ static int scalarproduct_fixed_c(const int *v1, const int *v2, int len)
     return (int)(p >> 31);
 }
 
-static void butterflies_fixed_c(int *v1, int *v2, int len)
+static void butterflies_fixed_c(int *v1s, int *v2, int len)
 {
     int i;
+    unsigned int *v1 = v1s;
 
     for (i = 0; i < len; i++){
         int t = v1[i] - v2[i];