diff --git a/libavcodec/atrac3.c b/libavcodec/atrac3.c
index ac240d7007..a9e98f807b 100644
--- a/libavcodec/atrac3.c
+++ b/libavcodec/atrac3.c
@@ -164,7 +164,10 @@ static int decode_bytes(const uint8_t *input, uint8_t *out, int bytes)
 
     off = (intptr_t)input & 3;
     buf = (const uint32_t *)(input - off);
-    c   = av_be2ne32((0x537F6103 >> (off * 8)) | (0x537F6103 << (32 - (off * 8))));
+    if (off)
+        c = av_be2ne32((0x537F6103U >> (off * 8)) | (0x537F6103U << (32 - (off * 8))));
+    else
+        c = av_be2ne32(0x537F6103U);
     bytes += 3 + off;
     for (i = 0; i < bytes / 4; i++)
         output[i] = c ^ buf[i];
diff --git a/libavformat/flacdec.c b/libavformat/flacdec.c
index 93f8f9df49..d5aacfd15f 100644
--- a/libavformat/flacdec.c
+++ b/libavformat/flacdec.c
@@ -278,11 +278,9 @@ fail:
 
 static int flac_probe(AVProbeData *p)
 {
-    const uint8_t *bufptr = p->buf;
-    const uint8_t *end    = p->buf + p->buf_size;
-
-    if(bufptr > end-4 || memcmp(bufptr, "fLaC", 4)) return 0;
-    else                                            return AVPROBE_SCORE_MAX/2;
+    if (p->buf_size < 4 || memcmp(p->buf, "fLaC", 4))
+        return 0;
+    return AVPROBE_SCORE_MAX/2;
 }
 
 AVInputFormat ff_flac_demuxer = {
diff --git a/libavutil/lzo.c b/libavutil/lzo.c
index c723257212..221a66b9ab 100644
--- a/libavutil/lzo.c
+++ b/libavutil/lzo.c
@@ -110,9 +110,8 @@ static inline void copy(LZOContext *c, int cnt)
  */
 static inline void copy_backptr(LZOContext *c, int back, int cnt)
 {
-    register const uint8_t *src = &c->out[-back];
     register uint8_t *dst       = c->out;
-    if (src < c->out_start || src > dst) {
+    if (dst - c->out_start < back) {
         c->error |= AV_LZO_INVALID_BACKPTR;
         return;
     }