1 files changed, 13 insertions, 38 deletions

diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c
index d884d2bb000..67254c2fd91 100644
--- a/src/backend/optimizer/util/pathnode.c
+++ b/src/backend/optimizer/util/pathnode.c
@@ -423,11 +423,9 @@ void
 add_path(RelOptInfo *parent_rel, Path *new_path)
 {
 	bool		accept_new = true;	/* unless we find a superior old path */
-	ListCell   *insert_after = NULL;	/* where to insert new item */
+	int			insert_at = 0;	/* where to insert new item */
 	List	   *new_path_pathkeys;
 	ListCell   *p1;
-	ListCell   *p1_prev;
-	ListCell   *p1_next;
 
 	/*
 	 * This is a convenient place to check for query cancel --- no part of the
@@ -442,12 +440,8 @@ add_path(RelOptInfo *parent_rel, Path *new_path)
 	 * Loop to check proposed new path against old paths.  Note it is possible
 	 * for more than one old path to be tossed out because new_path dominates
 	 * it.
-	 *
-	 * We can't use foreach here because the loop body may delete the current
-	 * list cell.
 	 */
-	p1_prev = NULL;
-	for (p1 = list_head(parent_rel->pathlist); p1 != NULL; p1 = p1_next)
+	foreach(p1, parent_rel->pathlist)
 	{
 		Path	   *old_path = (Path *) lfirst(p1);
 		bool		remove_old = false; /* unless new proves superior */
@@ -455,8 +449,6 @@ add_path(RelOptInfo *parent_rel, Path *new_path)
 		PathKeysComparison keyscmp;
 		BMS_Comparison outercmp;
 
-		p1_next = lnext(p1);
-
 		/*
 		 * Do a fuzzy cost comparison with standard fuzziness limit.
 		 */
@@ -593,23 +585,20 @@ add_path(RelOptInfo *parent_rel, Path *new_path)
 		 */
 		if (remove_old)
 		{
-			parent_rel->pathlist = list_delete_cell(parent_rel->pathlist,
-													p1, p1_prev);
+			parent_rel->pathlist = foreach_delete_current(parent_rel->pathlist,
+														  p1);
 
 			/*
 			 * Delete the data pointed-to by the deleted cell, if possible
 			 */
 			if (!IsA(old_path, IndexPath))
 				pfree(old_path);
-			/* p1_prev does not advance */
 		}
 		else
 		{
 			/* new belongs after this old path if it has cost >= old's */
 			if (new_path->total_cost >= old_path->total_cost)
-				insert_after = p1;
-			/* p1_prev advances */
-			p1_prev = p1;
+				insert_at = foreach_current_index(p1) + 1;
 		}
 
 		/*
@@ -624,10 +613,8 @@ add_path(RelOptInfo *parent_rel, Path *new_path)
 	if (accept_new)
 	{
 		/* Accept the new path: insert it at proper place in pathlist */
-		if (insert_after)
-			lappend_cell(parent_rel->pathlist, insert_after, new_path);
-		else
-			parent_rel->pathlist = lcons(new_path, parent_rel->pathlist);
+		parent_rel->pathlist =
+			list_insert_nth(parent_rel->pathlist, insert_at, new_path);
 	}
 	else
 	{
@@ -763,10 +750,8 @@ void
 add_partial_path(RelOptInfo *parent_rel, Path *new_path)
 {
 	bool		accept_new = true;	/* unless we find a superior old path */
-	ListCell   *insert_after = NULL;	/* where to insert new item */
+	int			insert_at = 0;	/* where to insert new item */
 	ListCell   *p1;
-	ListCell   *p1_prev;
-	ListCell   *p1_next;
 
 	/* Check for query cancel. */
 	CHECK_FOR_INTERRUPTS();
@@ -781,16 +766,12 @@ add_partial_path(RelOptInfo *parent_rel, Path *new_path)
 	 * As in add_path, throw out any paths which are dominated by the new
 	 * path, but throw out the new path if some existing path dominates it.
 	 */
-	p1_prev = NULL;
-	for (p1 = list_head(parent_rel->partial_pathlist); p1 != NULL;
-		 p1 = p1_next)
+	foreach(p1, parent_rel->partial_pathlist)
 	{
 		Path	   *old_path = (Path *) lfirst(p1);
 		bool		remove_old = false; /* unless new proves superior */
 		PathKeysComparison keyscmp;
 
-		p1_next = lnext(p1);
-
 		/* Compare pathkeys. */
 		keyscmp = compare_pathkeys(new_path->pathkeys, old_path->pathkeys);
 
@@ -841,17 +822,14 @@ add_partial_path(RelOptInfo *parent_rel, Path *new_path)
 		if (remove_old)
 		{
 			parent_rel->partial_pathlist =
-				list_delete_cell(parent_rel->partial_pathlist, p1, p1_prev);
+				foreach_delete_current(parent_rel->partial_pathlist, p1);
 			pfree(old_path);
-			/* p1_prev does not advance */
 		}
 		else
 		{
 			/* new belongs after this old path if it has cost >= old's */
 			if (new_path->total_cost >= old_path->total_cost)
-				insert_after = p1;
-			/* p1_prev advances */
-			p1_prev = p1;
+				insert_at = foreach_current_index(p1) + 1;
 		}
 
 		/*
@@ -866,11 +844,8 @@ add_partial_path(RelOptInfo *parent_rel, Path *new_path)
 	if (accept_new)
 	{
 		/* Accept the new path: insert it at proper place */
-		if (insert_after)
-			lappend_cell(parent_rel->partial_pathlist, insert_after, new_path);
-		else
-			parent_rel->partial_pathlist =
-				lcons(new_path, parent_rel->partial_pathlist);
+		parent_rel->partial_pathlist =
+			list_insert_nth(parent_rel->partial_pathlist, insert_at, new_path);
 	}
 	else
 	{