diff --git a/src/port/pg_popcount_avx512.c b/src/port/pg_popcount_avx512.c
index dacc7553d29..f6e718b86e9 100644
--- a/src/port/pg_popcount_avx512.c
+++ b/src/port/pg_popcount_avx512.c
@@ -52,13 +52,21 @@ pg_popcount_avx512(const char *buf, int bytes)
 	 * Iterate through all but the final iteration.  Starting from second
 	 * iteration, the start index mask is ignored.
 	 */
-	for (; buf < final; buf += sizeof(__m512i))
+	if (buf < final)
 	{
 		val = _mm512_maskz_loadu_epi8(mask, (const __m512i *) buf);
 		cnt = _mm512_popcnt_epi64(val);
 		accum = _mm512_add_epi64(accum, cnt);
 
+		buf += sizeof(__m512i);
 		mask = ~UINT64CONST(0);
+
+		for (; buf < final; buf += sizeof(__m512i))
+		{
+			val = _mm512_load_si512((const __m512i *) buf);
+			cnt = _mm512_popcnt_epi64(val);
+			accum = _mm512_add_epi64(accum, cnt);
+		}
 	}
 
 	/* Final iteration needs to ignore bytes that are not within the length */