diff --git a/src/dbuf.c b/src/dbuf.c
index 8cf6c80..c5cd1ce 100644
--- a/src/dbuf.c
+++ b/src/dbuf.c
@@ -50,7 +50,10 @@ uc_dbuf_ensure(DBuf *buf, size_t capacity)
         return 0;
     len = uc_dbuf_len(buf);
     sz = buf->start - buf->bufstart;
-    memmove(buf->bufstart, buf->start, len);
+
+    if (buf->bufstart != buf->start)
+        memmove(buf->bufstart, buf->start, len);
+
     if (sz + remaining < capacity) {
         size_t newlen = uc_dbuf_buflen(buf) + capacity;
         void *tmp = realloc(buf->bufstart, newlen);
@@ -75,7 +78,8 @@ uc_dbuf_trim(DBuf *buf)
     if (len == 0)
         return;
 
-    memmove(buf->bufstart, buf->start, len);
+    if (buf->bufstart != buf->start)
+        memmove(buf->bufstart, buf->start, len);
 
     tmp = realloc(buf->bufstart, len);
     if (tmp != NULL)