diff --git a/libavcodec/libmp3lame.c b/libavcodec/libmp3lame.c
index e60856c10b..19f88abf7f 100644
--- a/libavcodec/libmp3lame.c
+++ b/libavcodec/libmp3lame.c
@@ -218,7 +218,7 @@ static int mp3lame_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
         }
     } else {
         lame_result = lame_encode_flush(s->gfp, s->buffer + s->buffer_index,
-                                        BUFFER_SIZE - s->buffer_index);
+                                        s->buffer_size - s->buffer_index);
     }
     if (lame_result < 0) {
         if (lame_result == -1) {
diff --git a/libavcodec/png.c b/libavcodec/png.c
index a4287bd7e2..b398d91000 100644
--- a/libavcodec/png.c
+++ b/libavcodec/png.c
@@ -38,9 +38,7 @@ static const uint8_t ff_png_pass_xshift[NB_PASSES] = {
 
 void *ff_png_zalloc(void *opaque, unsigned int items, unsigned int size)
 {
-    if(items >= UINT_MAX / size)
-        return NULL;
-    return av_malloc(items * size);
+    return av_mallocz_array(items, size);
 }
 
 void ff_png_zfree(void *opaque, void *ptr)
diff --git a/libavutil/atomic_gcc.h b/libavutil/atomic_gcc.h
index 84ebcab768..2bb43c3cea 100644
--- a/libavutil/atomic_gcc.h
+++ b/libavutil/atomic_gcc.h
@@ -21,6 +21,8 @@
 #ifndef AVUTIL_ATOMIC_GCC_H
 #define AVUTIL_ATOMIC_GCC_H
 
+#include <stdint.h>
+
 #include "atomic.h"
 
 #define avpriv_atomic_int_get atomic_int_get_gcc
@@ -47,7 +49,13 @@ static inline int atomic_int_add_and_fetch_gcc(volatile int *ptr, int inc)
 static inline void *atomic_ptr_cas_gcc(void * volatile *ptr,
                                        void *oldval, void *newval)
 {
+#ifdef __ARMCC_VERSION
+    // armcc will throw an error if ptr is not an integer type
+    volatile uintptr_t *tmp = (volatile uintptr_t*)ptr;
+    return (void*)__sync_val_compare_and_swap(tmp, oldval, newval);
+#else
     return __sync_val_compare_and_swap(ptr, oldval, newval);
+#endif
 }
 
 #endif /* AVUTIL_ATOMIC_GCC_H */