diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 716de171a4..bbc9b262a0 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -2570,6 +2570,7 @@ CompareIndexInfo(const IndexInfo *info1, const IndexInfo *info2,
 
 		/* ignore expressions at this stage */
 		if ((info1->ii_IndexAttrNumbers[i] != InvalidAttrNumber) &&
+			(info2->ii_IndexAttrNumbers[i] != InvalidAttrNumber) &&
 			(attmap->attnums[info2->ii_IndexAttrNumbers[i] - 1] !=
 			 info1->ii_IndexAttrNumbers[i]))
 			return false;