diff --git a/src/port/pg_popcount_avx512.c b/src/port/pg_popcount_avx512.c
index f86558d1ee5..7fb2ada16c9 100644
--- a/src/port/pg_popcount_avx512.c
+++ b/src/port/pg_popcount_avx512.c
@@ -30,20 +30,27 @@
 uint64
 pg_popcount_avx512(const char *buf, int bytes)
 {
-	uint64		popcnt;
+	__m512i		val, cnt;
+	__mmask64	remaining_mask;
 	__m512i		accum = _mm512_setzero_si512();
 
-	for (; bytes >= sizeof(__m512i); bytes -= sizeof(__m512i))
+	#pragma clang loop unroll(disable)
+	for (; bytes > sizeof(__m512i); bytes -= sizeof(__m512i))
 	{
-		const		__m512i val = _mm512_loadu_si512((const __m512i *) buf);
-		const		__m512i cnt = _mm512_popcnt_epi64(val);
+		val = _mm512_loadu_si512((const __m512i *) buf);
+		cnt = _mm512_popcnt_epi64(val);
 
 		accum = _mm512_add_epi64(accum, cnt);
 		buf += sizeof(__m512i);
 	}
 
-	popcnt = _mm512_reduce_add_epi64(accum);
-	return popcnt + pg_popcount_fast(buf, bytes);
+	remaining_mask = ~0ULL >> (sizeof(__m512i) - bytes);
+	val = _mm512_maskz_loadu_epi8(remaining_mask, (const __m512i *) buf);
+	cnt = _mm512_popcnt_epi64(val);
+
+	accum = _mm512_add_epi64(accum, cnt);
+
+	return _mm512_reduce_add_epi64(accum);
 }
 
 #endif							/* TRY_POPCNT_FAST */