From: Sven Verdoolaege <skimo@kotnet.org>
Date: Fri, 7 Dec 2012 12:20:15 +0000 (+0100)
Subject: isl_map_inline_foreach_basic_map: drop basic maps that have become empty
X-Git-Tag: isl-0.12~217
X-Git-Url: https://repo.or.cz/w/isl.git/commitdiff_plain/8eb82109cb862a4fdd9d0168c978c9d547c315ba

isl_map_inline_foreach_basic_map: drop basic maps that have become empty

In particular, drop basic maps that have become empty in
isl_map_detect_equalities (which calls isl_map_inline_foreach_basic_map).

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>
---

diff --git a/isl_affine_hull.c b/isl_affine_hull.c
index e71bc104..edfefe4e 100644
--- a/isl_affine_hull.c
+++ b/isl_affine_hull.c
@@ -1126,30 +1126,6 @@ __isl_give isl_basic_set *isl_basic_set_detect_equalities(
 		isl_basic_map_detect_equalities((isl_basic_map *)bset);
 }
 
-__isl_give isl_map *isl_map_inline_foreach_basic_map(__isl_take isl_map *map,
-	__isl_give isl_basic_map *(*fn)(__isl_take isl_basic_map *bmap))
-{
-	struct isl_basic_map *bmap;
-	int i;
-
-	if (!map)
-		return NULL;
-
-	for (i = 0; i < map->n; ++i) {
-		bmap = isl_basic_map_copy(map->p[i]);
-		bmap = fn(bmap);
-		if (!bmap)
-			goto error;
-		isl_basic_map_free(map->p[i]);
-		map->p[i] = bmap;
-	}
-
-	return map;
-error:
-	isl_map_free(map);
-	return NULL;
-}
-
 __isl_give isl_map *isl_map_detect_equalities(__isl_take isl_map *map)
 {
 	return isl_map_inline_foreach_basic_map(map,
diff --git a/isl_map.c b/isl_map.c
index 51a8600b..b0554cff 100644
--- a/isl_map.c
+++ b/isl_map.c
@@ -5331,6 +5331,39 @@ static int remove_if_empty(__isl_keep isl_map *map, int i)
 	return 0;
 }
 
+/* Perform "fn" on each basic map of "map", where we may not be holding
+ * the only reference to "map".
+ * In particular, "fn" should be a semantics preserving operation
+ * that we want to apply to all copies of "map".  We therefore need
+ * to be careful not to modify "map" in a way that breaks "map"
+ * in case anything goes wrong.
+ */
+__isl_give isl_map *isl_map_inline_foreach_basic_map(__isl_take isl_map *map,
+	__isl_give isl_basic_map *(*fn)(__isl_take isl_basic_map *bmap))
+{
+	struct isl_basic_map *bmap;
+	int i;
+
+	if (!map)
+		return NULL;
+
+	for (i = map->n - 1; i >= 0; --i) {
+		bmap = isl_basic_map_copy(map->p[i]);
+		bmap = fn(bmap);
+		if (!bmap)
+			goto error;
+		isl_basic_map_free(map->p[i]);
+		map->p[i] = bmap;
+		if (remove_if_empty(map, i) < 0)
+			goto error;
+	}
+
+	return map;
+error:
+	isl_map_free(map);
+	return NULL;
+}
+
 struct isl_map *isl_map_fix_si(struct isl_map *map,
 		enum isl_dim_type type, unsigned pos, int value)
 {