diff --git a/src/backend/access/gist/gistxlog.c b/src/backend/access/gist/gistxlog.c
index b4f629f4a8..998befd2cb 100644
--- a/src/backend/access/gist/gistxlog.c
+++ b/src/backend/access/gist/gistxlog.c
@@ -81,7 +81,7 @@ gistRedoPageUpdateRecord(XLogReaderState *record)
 		char	   *begin;
 		char	   *data;
 		Size		datalen;
-		int			ninserted = 0;
+		int			ninserted PG_USED_FOR_ASSERTS_ONLY = 0;
 
 		data = begin = XLogRecGetBlockData(record, 0, &datalen);
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index eb0430fe98..e028124672 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -1785,7 +1785,7 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, TimeLineID tli, bool opportunistic)
 	XLogRecPtr	NewPageEndPtr = InvalidXLogRecPtr;
 	XLogRecPtr	NewPageBeginPtr;
 	XLogPageHeader NewPage;
-	int			npages = 0;
+	int			npages pg_attribute_unused() = 0;
 
 	LWLockAcquire(WALBufMappingLock, LW_EXCLUSIVE);
 
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 82f03fc9c9..c6ec694ceb 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -864,6 +864,7 @@ parse_toplevel:
 			stmtmulti
 			{
 				pg_yyget_extra(yyscanner)->parsetree = $1;
+				(void) yynerrs;		/* suppress compiler warning */
 			}
 			| MODE_TYPE_NAME Typename
 			{
diff --git a/src/backend/utils/adt/array_typanalyze.c b/src/backend/utils/adt/array_typanalyze.c
index 1964cedd93..2360c680ac 100644
--- a/src/backend/utils/adt/array_typanalyze.c
+++ b/src/backend/utils/adt/array_typanalyze.c
@@ -218,7 +218,6 @@ compute_array_stats(VacAttrStats *stats, AnalyzeAttrFetchFunc fetchfunc,
 {
 	ArrayAnalyzeExtraData *extra_data;
 	int			num_mcelem;
-	int			null_cnt = 0;
 	int			null_elem_cnt = 0;
 	int			analyzed_rows = 0;
 
@@ -320,8 +319,7 @@ compute_array_stats(VacAttrStats *stats, AnalyzeAttrFetchFunc fetchfunc,
 		value = fetchfunc(stats, array_no, &isnull);
 		if (isnull)
 		{
-			/* array is null, just count that */
-			null_cnt++;
+			/* ignore arrays that are null overall */
 			continue;
 		}
 
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 7e28853a57..2a56629cc3 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -113,6 +113,7 @@ result:
 										*result = palloc(sizeof(JsonPathParseResult));
 										(*result)->expr = $2;
 										(*result)->lax = $1;
+										(void) yynerrs;
 									}
 	| /* EMPTY */					{ *result = NULL; }
 	;
diff --git a/src/bin/pgbench/exprparse.y b/src/bin/pgbench/exprparse.y
index ade2ecdaab..f6387d4a3c 100644
--- a/src/bin/pgbench/exprparse.y
+++ b/src/bin/pgbench/exprparse.y
@@ -80,7 +80,10 @@ static PgBenchExpr *make_case(yyscan_t yyscanner, PgBenchExprList *when_then_lis
 
 %%
 
-result: expr				{ expr_parse_result = $1; }
+result: expr				{
+								expr_parse_result = $1;
+								(void) yynerrs; /* suppress compiler warning */
+							}
 
 elist:						{ $$ = NULL; }
 	| expr					{ $$ = make_elist($1, NULL); }