Remove local optimizations of empty Bitmapsets into null pointers.

These are all dead code now that it's done centrally.

Patch by me; thanks to Nathan Bossart and Richard Guo for review.

Discussion: https://postgr.es/m/1159933.1677621588@sss.pgh.pa.us

1 files changed, 4 insertions, 15 deletions

diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index 04718f66c0b..d28d0da6214 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -1247,16 +1247,11 @@ remove_nulling_relids_mutator(Node *node,
 			!bms_is_member(var->varno, context->except_relids) &&
 			bms_overlap(var->varnullingrels, context->removable_relids))
 		{
-			Relids		newnullingrels = bms_difference(var->varnullingrels,
-														context->removable_relids);
-
-			/* Micro-optimization: ensure nullingrels is NULL if empty */
-			if (bms_is_empty(newnullingrels))
-				newnullingrels = NULL;
 			/* Copy the Var ... */
 			var = copyObject(var);
 			/* ... and replace the copy's varnullingrels field */
-			var->varnullingrels = newnullingrels;
+			var->varnullingrels = bms_difference(var->varnullingrels,
+												 context->removable_relids);
 			return (Node *) var;
 		}
 		/* Otherwise fall through to copy the Var normally */
@@ -1268,26 +1263,20 @@ remove_nulling_relids_mutator(Node *node,
 		if (phv->phlevelsup == context->sublevels_up &&
 			!bms_overlap(phv->phrels, context->except_relids))
 		{
-			Relids		newnullingrels = bms_difference(phv->phnullingrels,
-														context->removable_relids);
-
 			/*
-			 * Micro-optimization: ensure nullingrels is NULL if empty.
-			 *
 			 * Note: it might seem desirable to remove the PHV altogether if
 			 * phnullingrels goes to empty.  Currently we dare not do that
 			 * because we use PHVs in some cases to enforce separate identity
 			 * of subexpressions; see wrap_non_vars usages in prepjointree.c.
 			 */
-			if (bms_is_empty(newnullingrels))
-				newnullingrels = NULL;
 			/* Copy the PlaceHolderVar and mutate what's below ... */
 			phv = (PlaceHolderVar *)
 				expression_tree_mutator(node,
 										remove_nulling_relids_mutator,
 										(void *) context);
 			/* ... and replace the copy's phnullingrels field */
-			phv->phnullingrels = newnullingrels;
+			phv->phnullingrels = bms_difference(phv->phnullingrels,
+												context->removable_relids);
 			/* We must also update phrels, if it contains a removable RTI */
 			phv->phrels = bms_difference(phv->phrels,
 										 context->removable_relids);