From d646efd5d7a3f60e98d02c6bd23b9ee7c06e9d89 Mon Sep 17 00:00:00 2001
From: Sven Verdoolaege <skimo@kotnet.org>
Date: Thu, 23 Jul 2009 18:51:26 +0200
Subject: [PATCH] isl_tab.c: mark_redundant: only mark variable nonneg if they
 weren't already

More imporantly, don't undo such a mark during rollback.
---
 isl_tab.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/isl_tab.c b/isl_tab.c
index 3f6d5d13..cdc173a0 100644
--- a/isl_tab.c
+++ b/isl_tab.c
@@ -354,7 +354,7 @@ static int mark_redundant(struct isl_tab *tab, int row)
 	var->is_redundant = 1;
 	isl_assert(tab->mat->ctx, row >= tab->n_redundant, return);
 	if (tab->need_undo || tab->row_var[row] >= 0) {
-		if (tab->row_var[row] >= 0) {
+		if (tab->row_var[row] >= 0 && !var->is_nonneg) {
 			var->is_nonneg = 1;
 			push(tab, isl_tab_undo_nonneg, var);
 		}
-- 
2.11.4.GIT