diff --git a/contrib/pageinspect/btreefuncs.c b/contrib/pageinspect/btreefuncs.c
index d50ec3a..2ec265e 100644
--- a/contrib/pageinspect/btreefuncs.c
+++ b/contrib/pageinspect/btreefuncs.c
@@ -363,8 +363,8 @@ bt_page_items(PG_FUNCTION_ARGS)
 		j = 0;
 		values[j++] = psprintf("%d", uargs->offset);
 		values[j++] = psprintf("(%u,%u)",
-							   BlockIdGetBlockNumber(&(itup->t_tid.ip_blkid)),
-							   itup->t_tid.ip_posid);
+							   ItemPointerGetBlockNumberNoCheck(&itup->t_tid),
+							   ItemPointerGetOffsetNumberNoCheck(&itup->t_tid));
 		values[j++] = psprintf("%d", (int) IndexTupleSize(itup));
 		values[j++] = psprintf("%c", IndexTupleHasNulls(itup) ? 't' : 'f');
 		values[j++] = psprintf("%c", IndexTupleHasVarwidths(itup) ? 't' : 'f');
diff --git a/contrib/pgstattuple/pgstattuple.c b/contrib/pgstattuple/pgstattuple.c
index 06a1992..e65040d 100644
--- a/contrib/pgstattuple/pgstattuple.c
+++ b/contrib/pgstattuple/pgstattuple.c
@@ -353,7 +353,7 @@ pgstat_heap(Relation rel, FunctionCallInfo fcinfo)
 		 * heap_getnext may find no tuples on a given page, so we cannot
 		 * simply examine the pages returned by the heap scan.
 		 */
-		tupblock = BlockIdGetBlockNumber(&tuple->t_self.ip_blkid);
+		tupblock = ItemPointerGetBlockNumber(&tuple->t_self);
 
 		while (block <= tupblock)
 		{
diff --git a/src/backend/access/gin/ginget.c b/src/backend/access/gin/ginget.c
index 60f005c..b4e9fec 100644
--- a/src/backend/access/gin/ginget.c
+++ b/src/backend/access/gin/ginget.c
@@ -626,8 +626,9 @@ entryLoadMoreItems(GinState *ginstate, GinScanEntry entry,
 		}
 		else
 		{
-			entry->btree.itemptr = advancePast;
-			entry->btree.itemptr.ip_posid++;
+			ItemPointerSet(&entry->btree.itemptr,
+					GinItemPointerGetBlockNumber(&advancePast),
+					OffsetNumberNext(GinItemPointerGetOffsetNumber(&advancePast)));
 		}
 		entry->btree.fullScan = false;
 		stack = ginFindLeafPage(&entry->btree, true, snapshot);
@@ -979,15 +980,17 @@ keyGetItem(GinState *ginstate, MemoryContext tempCtx, GinScanKey key,
 		if (GinItemPointerGetBlockNumber(&advancePast) <
 			GinItemPointerGetBlockNumber(&minItem))
 		{
-			advancePast.ip_blkid = minItem.ip_blkid;
-			advancePast.ip_posid = 0;
+			ItemPointerSet(&advancePast,
+					GinItemPointerGetBlockNumber(&minItem),
+					InvalidOffsetNumber);
 		}
 	}
 	else
 	{
-		Assert(minItem.ip_posid > 0);
-		advancePast = minItem;
-		advancePast.ip_posid--;
+		Assert(GinItemPointerGetOffsetNumber(&minItem) > 0);
+		ItemPointerSet(&advancePast,
+				GinItemPointerGetBlockNumber(&minItem),
+				OffsetNumberPrev(GinItemPointerGetOffsetNumber(&minItem)));
 	}
 
 	/*
@@ -1245,15 +1248,17 @@ scanGetItem(IndexScanDesc scan, ItemPointerData advancePast,
 				if (GinItemPointerGetBlockNumber(&advancePast) <
 					GinItemPointerGetBlockNumber(&key->curItem))
 				{
-					advancePast.ip_blkid = key->curItem.ip_blkid;
-					advancePast.ip_posid = 0;
+					ItemPointerSet(&advancePast,
+						GinItemPointerGetBlockNumber(&key->curItem),
+						InvalidOffsetNumber);
 				}
 			}
 			else
 			{
-				Assert(key->curItem.ip_posid > 0);
-				advancePast = key->curItem;
-				advancePast.ip_posid--;
+				Assert(GinItemPointerGetOffsetNumber(&key->curItem) > 0);
+				ItemPointerSet(&advancePast,
+						GinItemPointerGetBlockNumber(&key->curItem),
+						OffsetNumberPrev(GinItemPointerGetOffsetNumber(&key->curItem)));
 			}
 
 			/*
diff --git a/src/backend/access/gin/ginpostinglist.c b/src/backend/access/gin/ginpostinglist.c
index 598069d..8d2d31a 100644
--- a/src/backend/access/gin/ginpostinglist.c
+++ b/src/backend/access/gin/ginpostinglist.c
@@ -79,13 +79,11 @@ itemptr_to_uint64(const ItemPointer iptr)
 	uint64		val;
 
 	Assert(ItemPointerIsValid(iptr));
-	Assert(iptr->ip_posid < (1 << MaxHeapTuplesPerPageBits));
+	Assert(GinItemPointerGetOffsetNumber(iptr) < (1 << MaxHeapTuplesPerPageBits));
 
-	val = iptr->ip_blkid.bi_hi;
-	val <<= 16;
-	val |= iptr->ip_blkid.bi_lo;
+	val = GinItemPointerGetBlockNumber(iptr);
 	val <<= MaxHeapTuplesPerPageBits;
-	val |= iptr->ip_posid;
+	val |= GinItemPointerGetOffsetNumber(iptr);
 
 	return val;
 }
@@ -93,11 +91,9 @@ itemptr_to_uint64(const ItemPointer iptr)
 static inline void
 uint64_to_itemptr(uint64 val, ItemPointer iptr)
 {
-	iptr->ip_posid = val & ((1 << MaxHeapTuplesPerPageBits) - 1);
+	GinItemPointerSetOffsetNumber(iptr, val & ((1 << MaxHeapTuplesPerPageBits) - 1));
 	val = val >> MaxHeapTuplesPerPageBits;
-	iptr->ip_blkid.bi_lo = val & 0xFFFF;
-	val = val >> 16;
-	iptr->ip_blkid.bi_hi = val & 0xFFFF;
+	GinItemPointerSetBlockNumber(iptr, val);
 
 	Assert(ItemPointerIsValid(iptr));
 }
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 7dc97fa..152be87 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -3048,8 +3048,8 @@ DisplayMapping(HTAB *tuplecid_data)
 			 ent->key.relnode.dbNode,
 			 ent->key.relnode.spcNode,
 			 ent->key.relnode.relNode,
-			 BlockIdGetBlockNumber(&ent->key.tid.ip_blkid),
-			 ent->key.tid.ip_posid,
+			 ItemPointerGetBlockNumber(&ent->key.tid),
+			 ItemPointerGetOffsetNumber(&ent->key.tid),
 			 ent->cmin,
 			 ent->cmax
 			);
diff --git a/src/backend/storage/page/itemptr.c b/src/backend/storage/page/itemptr.c
index 703cbb9..28ac885 100644
--- a/src/backend/storage/page/itemptr.c
+++ b/src/backend/storage/page/itemptr.c
@@ -54,18 +54,21 @@ ItemPointerCompare(ItemPointer arg1, ItemPointer arg2)
 	/*
 	 * Don't use ItemPointerGetBlockNumber or ItemPointerGetOffsetNumber here,
 	 * because they assert ip_posid != 0 which might not be true for a
-	 * user-supplied TID.
+	 * user-supplied TID. Instead we use ItemPointerGetBlockNumberNoCheck and
+	 * ItemPointerGetOffsetNumberNoCheck which do not do any validation.
 	 */
-	BlockNumber b1 = BlockIdGetBlockNumber(&(arg1->ip_blkid));
-	BlockNumber b2 = BlockIdGetBlockNumber(&(arg2->ip_blkid));
+	BlockNumber b1 = ItemPointerGetBlockNumberNoCheck(arg1);
+	BlockNumber b2 = ItemPointerGetBlockNumberNoCheck(arg2);
 
 	if (b1 < b2)
 		return -1;
 	else if (b1 > b2)
 		return 1;
-	else if (arg1->ip_posid < arg2->ip_posid)
+	else if (ItemPointerGetOffsetNumberNoCheck(arg1) <
+			ItemPointerGetOffsetNumberNoCheck(arg2))
 		return -1;
-	else if (arg1->ip_posid > arg2->ip_posid)
+	else if (ItemPointerGetOffsetNumberNoCheck(arg1) >
+			ItemPointerGetOffsetNumberNoCheck(arg2))
 		return 1;
 	else
 		return 0;
diff --git a/src/backend/utils/adt/tid.c b/src/backend/utils/adt/tid.c
index a3b372f..735c006 100644
--- a/src/backend/utils/adt/tid.c
+++ b/src/backend/utils/adt/tid.c
@@ -109,8 +109,8 @@ tidout(PG_FUNCTION_ARGS)
 	OffsetNumber offsetNumber;
 	char		buf[32];
 
-	blockNumber = BlockIdGetBlockNumber(&(itemPtr->ip_blkid));
-	offsetNumber = itemPtr->ip_posid;
+	blockNumber = ItemPointerGetBlockNumberNoCheck(itemPtr);
+	offsetNumber = ItemPointerGetOffsetNumberNoCheck(itemPtr);
 
 	/* Perhaps someday we should output this as a record. */
 	snprintf(buf, sizeof(buf), "(%u,%u)", blockNumber, offsetNumber);
@@ -146,14 +146,12 @@ Datum
 tidsend(PG_FUNCTION_ARGS)
 {
 	ItemPointer itemPtr = PG_GETARG_ITEMPOINTER(0);
-	BlockId		blockId;
 	BlockNumber blockNumber;
 	OffsetNumber offsetNumber;
 	StringInfoData buf;
 
-	blockId = &(itemPtr->ip_blkid);
-	blockNumber = BlockIdGetBlockNumber(blockId);
-	offsetNumber = itemPtr->ip_posid;
+	blockNumber = ItemPointerGetBlockNumberNoCheck(itemPtr);
+	offsetNumber = ItemPointerGetOffsetNumberNoCheck(itemPtr);
 
 	pq_begintypsend(&buf);
 	pq_sendint(&buf, blockNumber, sizeof(blockNumber));
diff --git a/src/include/access/gin_private.h b/src/include/access/gin_private.h
index 34e7339..2fd4479 100644
--- a/src/include/access/gin_private.h
+++ b/src/include/access/gin_private.h
@@ -460,8 +460,8 @@ extern ItemPointer ginMergeItemPointers(ItemPointerData *a, uint32 na,
 static inline int
 ginCompareItemPointers(ItemPointer a, ItemPointer b)
 {
-	uint64		ia = (uint64) a->ip_blkid.bi_hi << 32 | (uint64) a->ip_blkid.bi_lo << 16 | a->ip_posid;
-	uint64		ib = (uint64) b->ip_blkid.bi_hi << 32 | (uint64) b->ip_blkid.bi_lo << 16 | b->ip_posid;
+	uint64		ia = (uint64) GinItemPointerGetBlockNumber(a) << 32 | GinItemPointerGetOffsetNumber(a);
+	uint64		ib = (uint64) GinItemPointerGetBlockNumber(b) << 32 | GinItemPointerGetOffsetNumber(b);
 
 	if (ia == ib)
 		return 0;
diff --git a/src/include/access/ginblock.h b/src/include/access/ginblock.h
index a3fb056..438912c 100644
--- a/src/include/access/ginblock.h
+++ b/src/include/access/ginblock.h
@@ -132,10 +132,17 @@ typedef struct GinMetaPageData
  * to avoid Asserts, since sometimes the ip_posid isn't "valid"
  */
 #define GinItemPointerGetBlockNumber(pointer) \
-	BlockIdGetBlockNumber(&(pointer)->ip_blkid)
+	(ItemPointerGetBlockNumberNoCheck(pointer))
 
 #define GinItemPointerGetOffsetNumber(pointer) \
-	((pointer)->ip_posid)
+	(ItemPointerGetOffsetNumberNoCheck(pointer))
+
+#define GinItemPointerSetBlockNumber(pointer, blkno) \
+	(ItemPointerSetBlockNumber((pointer), (blkno)))
+
+#define GinItemPointerSetOffsetNumber(pointer, offnum) \
+	(ItemPointerSetOffsetNumber((pointer), (offnum)))
+
 
 /*
  * Special-case item pointer values needed by the GIN search logic.
diff --git a/src/include/access/htup_details.h b/src/include/access/htup_details.h
index a6c7e31..7b6285d 100644
--- a/src/include/access/htup_details.h
+++ b/src/include/access/htup_details.h
@@ -422,7 +422,7 @@ do { \
 
 #define HeapTupleHeaderIsSpeculative(tup) \
 ( \
-	(tup)->t_ctid.ip_posid == SpecTokenOffsetNumber \
+	(ItemPointerGetOffsetNumberNoCheck(&(tup)->t_ctid) == SpecTokenOffsetNumber) \
 )
 
 #define HeapTupleHeaderGetSpeculativeToken(tup) \
diff --git a/src/include/access/nbtree.h b/src/include/access/nbtree.h
index 6289ffa..f9304db 100644
--- a/src/include/access/nbtree.h
+++ b/src/include/access/nbtree.h
@@ -151,9 +151,8 @@ typedef struct BTMetaPageData
  *	within a level). - vadim 04/09/97
  */
 #define BTTidSame(i1, i2)	\
-	( (i1).ip_blkid.bi_hi == (i2).ip_blkid.bi_hi && \
-	  (i1).ip_blkid.bi_lo == (i2).ip_blkid.bi_lo && \
-	  (i1).ip_posid == (i2).ip_posid )
+	((ItemPointerGetBlockNumber(&(i1)) == ItemPointerGetBlockNumber(&(i2))) && \
+	 (ItemPointerGetOffsetNumber(&(i1)) == ItemPointerGetOffsetNumber(&(i2))))
 #define BTEntrySame(i1, i2) \
 	BTTidSame((i1)->t_tid, (i2)->t_tid)
 
diff --git a/src/include/storage/itemptr.h b/src/include/storage/itemptr.h
index 576aaa8..60d0070 100644
--- a/src/include/storage/itemptr.h
+++ b/src/include/storage/itemptr.h
@@ -69,6 +69,12 @@ typedef ItemPointerData *ItemPointer;
 	BlockIdGetBlockNumber(&(pointer)->ip_blkid) \
 )
 
+/* Same as ItemPointerGetBlockNumber but without any assert-checks */
+#define ItemPointerGetBlockNumberNoCheck(pointer) \
+( \
+	BlockIdGetBlockNumber(&(pointer)->ip_blkid) \
+)
+
 /*
  * ItemPointerGetOffsetNumber
  *		Returns the offset number of a disk item pointer.
@@ -79,6 +85,12 @@ typedef ItemPointerData *ItemPointer;
 	(pointer)->ip_posid \
 )
 
+/* Same as ItemPointerGetOffsetNumber but without any assert-checks */
+#define ItemPointerGetOffsetNumberNoCheck(pointer) \
+( \
+	(pointer)->ip_posid \
+)
+
 /*
  * ItemPointerSet
  *		Sets a disk item pointer to the specified block and offset.