diff --git a/src/bitops.c b/src/bitops.c
index 47f768c31..70146af37 100644
--- a/src/bitops.c
+++ b/src/bitops.c
@@ -58,8 +58,8 @@ static int getBitOffsetFromArgument(redisClient *c, robj *o, size_t *offset) {
 /* Count number of bits set in the binary array pointed by 's' and long
  * 'count' bytes. The implementation of this function is required to
  * work with a input string length up to 512 MB. */
-size_t popcount(void *s, long count) {
-    size_t bits = 0;
+long long popcount(void *s, long count) {
+    long long bits = 0;
     unsigned char *p;
     uint32_t *p4 = s;
     static const unsigned char bitsinbyte[256] = {0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,4,5,5,6,5,6,6,7,5,6,6,7,6,7,7,8};
diff --git a/src/redis.h b/src/redis.h
index 11fc7d662..d5ddfb8c5 100644
--- a/src/redis.h
+++ b/src/redis.h
@@ -984,7 +984,7 @@ long long mstime(void);
 void getRandomHexChars(char *p, unsigned int len);
 uint64_t crc64(uint64_t crc, const unsigned char *s, uint64_t l);
 void exitFromChild(int retcode);
-size_t popcount(void *s, long count);
+long long popcount(void *s, long count);
 void redisSetProcTitle(char *title);
 
 /* networking.c -- Networking and Client related operations */