diff --git a/libavcodec/dvdec.c b/libavcodec/dvdec.c
index fbd158f7d2..e759c91424 100644
--- a/libavcodec/dvdec.c
+++ b/libavcodec/dvdec.c
@@ -96,7 +96,7 @@ static void dv_decode_ac(GetBitContext *gb, BlockInfo *mb, int16_t *block)
     int partial_bit_count = mb->partial_bit_count;
     int level, run, vlc_len, index;
 
-    OPEN_READER(re, gb);
+    OPEN_READER_NOSIZE(re, gb);
     UPDATE_CACHE(re, gb);
 
     /* if we must parse a partial VLC, we do it here */
diff --git a/libavcodec/get_bits.h b/libavcodec/get_bits.h
index 02f850cee6..b9dec4fe35 100644
--- a/libavcodec/get_bits.h
+++ b/libavcodec/get_bits.h
@@ -125,17 +125,18 @@ typedef struct RL_VLC_ELEM {
 #   define MIN_CACHE_BITS 25
 #endif
 
-#if UNCHECKED_BITSTREAM_READER
-#define OPEN_READER(name, gb)                   \
+#define OPEN_READER_NOSIZE(name, gb)            \
     unsigned int name ## _index = (gb)->index;  \
     unsigned int av_unused name ## _cache
 
+#if UNCHECKED_BITSTREAM_READER
+#define OPEN_READER(name, gb) OPEN_READER_NOSIZE(name, gb)
+
 #define BITS_AVAILABLE(name, gb) 1
 #else
 #define OPEN_READER(name, gb)                   \
-    unsigned int name ## _index = (gb)->index;  \
-    unsigned int av_unused name ## _cache = 0;  \
-    unsigned int av_unused name ## _size_plus8 = (gb)->size_in_bits_plus8
+    OPEN_READER_NOSIZE(name, gb);               \
+    unsigned int name ## _size_plus8 = (gb)->size_in_bits_plus8
 
 #define BITS_AVAILABLE(name, gb) name ## _index < name ## _size_plus8
 #endif
@@ -286,7 +287,7 @@ static inline unsigned int get_bits_le(GetBitContext *s, int n)
 static inline unsigned int show_bits(GetBitContext *s, int n)
 {
     register int tmp;
-    OPEN_READER(re, s);
+    OPEN_READER_NOSIZE(re, s);
     av_assert2(n>0 && n<=25);
     UPDATE_CACHE(re, s);
     tmp = SHOW_UBITS(re, s, n);