avfilter/vf_edgedetect: fix undefined behaviour

Fixes #8287

diff --git a/libavfilter/vf_edgedetect.c b/libavfilter/vf_edgedetect.c
index 25424dbccec5a1947234db6ba5f10b4cdf623065..a5614ea63bba86ad0f478182b9fbaf0ca675680d 100644 (file)
--- a/libavfilter/vf_edgedetect.c
+++ b/libavfilter/vf_edgedetect.c
@@ -216,7 +216,7 @@ static int get_rounded_direction(int gx, int gy)
 
         if (gx < 0)
             gx = -gx, gy = -gy;
-        gy <<= 16;
+        gy *= (1 << 16);
         tanpi8gx  =  27146 * gx;
         tan3pi8gx = 158218 * gx;
         if (gy > -tan3pi8gx && gy < -tanpi8gx)  return DIRECTION_45UP;