--- src/shred-orig.c	2017-04-17 17:49:51.877401171 +0200
+++ src/shred.c	2017-04-17 17:50:39.875382422 +0200
@@ -287,7 +287,7 @@
   r[0] = (bits >> 4) & 255;
   r[1] = (bits >> 8) & 255;
   r[2] = bits & 255;
-  for (i = 3; i < size / 2; i *= 2)
+  for (i = 3; (i << 1) < size; i <<= 1)
     memcpy (r + i, r, i);
   if (i < size)
     memcpy (r + i, r, size - i);