From: Sven Verdoolaege <skimo@kotnet.org>
Date: Sat, 3 Mar 2012 22:52:06 +0000 (+0100)
Subject: isl_union_map_is_subset: properly handle non-obviously empty subsets
X-Git-Tag: isl-0.10~8^2~15
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a4d79e58fa4077f88b5242631f016a554ddc9c31;p=platform%2Fupstream%2Fisl.git

isl_union_map_is_subset: properly handle non-obviously empty subsets

If the first argument of isl_union_map_is_subset contains an empty
set in some space that is not present in the second argument,
then isl_union_map_is_subset would incorrectly draw the conclusion
that the first is not a subset of the second.

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

diff --git a/isl_union_map.c b/isl_union_map.c
index f62a302..d47df15 100644
--- a/isl_union_map.c
+++ b/isl_union_map.c
@@ -1672,6 +1672,11 @@ static int is_subset_entry(void **entry, void *user)
 	entry2 = isl_hash_table_find(data->umap2->dim->ctx, &data->umap2->table,
 				     hash, &has_dim, map->dim, 0);
 	if (!entry2) {
+		int empty = isl_map_is_empty(map);
+		if (empty < 0)
+			return -1;
+		if (empty)
+			return 0;
 		data->is_subset = 0;
 		return -1;
 	}