Add debug for CI XXX not for commit

Author: j-naylor

src/port/pg_crc32c_sse42.c

@@ -21,6 +21,8 @@
 
 #include "port/pg_crc32c.h"
 
+#define DEBUG_CRC				/* XXX not for commit, or at least comment out */
+
 pg_attribute_no_sanitize_alignment()
 pg_attribute_target("sse4.2")
 pg_crc32c
@@ -98,6 +100,9 @@ pg_comp_crc32c_avx512(pg_crc32c crc, const void *data, size_t length)
 	pg_crc32c	crc0 = crc;
 	size_t		len = length;
 	const char *buf = data;
+#ifdef DEBUG_CRC
+	const size_t orig_len PG_USED_FOR_ASSERTS_ONLY = len;
+#endif
 
 	/* Align on cacheline boundary. The threshold is somewhat arbitrary. */
 	if (unlikely(len > 256))
@@ -156,7 +161,13 @@ pg_comp_crc32c_avx512(pg_crc32c crc, const void *data, size_t length)
 		len = end - buf;
 	}
 
-	return pg_comp_crc32c_sse42(crc0, buf, len);
+	crc0 = pg_comp_crc32c_sse42(crc0, buf, len);
+
+#ifdef DEBUG_CRC
+	Assert(crc0 == pg_comp_crc32c_sse42(crc, data, orig_len));
+#endif
+
+	return crc0;
 }
 
 #endif