From 79776976e2fee1f831190a0fc30cd6984566f5de Mon Sep 17 00:00:00 2001
From: Sven Verdoolaege <skimo@kotnet.org>
Date: Sat, 28 Nov 2009 16:09:56 +0100
Subject: [PATCH] isl_tab_add_ineq and isl_tab_mark_empty: return status
 instead of isl_tab *

isl_tabs are not reference counted, so it's easier to deal with a status
than to have to keep track of whether the isl_tab may have been destroyed.
---
 isl_affine_hull.c  |  5 ++--
 isl_map_simplify.c |  3 ++-
 isl_sample.c       |  5 ++--
 isl_tab.c          | 70 ++++++++++++++++++++++++++++++------------------------
 isl_tab.h          |  4 ++--
 isl_tab_pip.c      | 55 +++++++++++++++++++++++++++++-------------
 6 files changed, 88 insertions(+), 54 deletions(-)

diff --git a/isl_affine_hull.c b/isl_affine_hull.c
index a133598..17dd7d8 100644
--- a/isl_affine_hull.c
+++ b/isl_affine_hull.c
@@ -239,7 +239,7 @@ error:
 static struct isl_vec *outside_point(struct isl_tab *tab, isl_int *eq, int up)
 {
 	struct isl_ctx *ctx;
-	struct isl_vec *sample;
+	struct isl_vec *sample = NULL;
 	struct isl_tab_undo *snap;
 	unsigned dim;
 	int k;
@@ -269,7 +269,8 @@ static struct isl_vec *outside_point(struct isl_tab *tab, isl_int *eq, int up)
 
 	if (isl_tab_extend_cons(tab, 1) < 0)
 		goto error;
-	tab = isl_tab_add_ineq(tab, eq);
+	if (isl_tab_add_ineq(tab, eq) < 0)
+		goto error;
 
 	sample = isl_tab_sample(tab);
 
diff --git a/isl_map_simplify.c b/isl_map_simplify.c
index ed9e033..354de11 100644
--- a/isl_map_simplify.c
+++ b/isl_map_simplify.c
@@ -1581,7 +1581,8 @@ static struct isl_basic_set *uset_gist(struct isl_basic_set *bset,
 	if (!tab)
 		goto error;
 	for (i = 0; i < bset->n_ineq; ++i)
-		tab = isl_tab_add_ineq(tab, bset->ineq[i]);
+		if (isl_tab_add_ineq(tab, bset->ineq[i]) < 0)
+			goto error;
 	bset = isl_basic_set_add_constraints(combined, bset, 0);
 	tab = isl_tab_detect_implicit_equalities(tab);
 	tab = isl_tab_detect_redundant(tab);
diff --git a/isl_sample.c b/isl_sample.c
index 4e2cdd6..83fbf4e 100644
--- a/isl_sample.c
+++ b/isl_sample.c
@@ -957,6 +957,7 @@ static int tab_shift_cone(struct isl_tab *tab,
 	bset = tab_cone->bset;
 	U = isl_mat_drop_cols(U, 0, tab->n_var - tab->n_unbounded);
 	for (i = 0; i < bset->n_ineq; ++i) {
+		int ok;
 		struct isl_vec *row = NULL;
 		if (isl_tab_is_equality(tab_cone, tab_cone->n_eq + i))
 			continue;
@@ -973,9 +974,9 @@ static int tab_shift_cone(struct isl_tab *tab,
 			continue;
 		tab = isl_tab_extend(tab, 1);
 		isl_int_add(bset->ineq[i][0], bset->ineq[i][0], v);
-		tab = isl_tab_add_ineq(tab, bset->ineq[i]);
+		ok = isl_tab_add_ineq(tab, bset->ineq[i]) >= 0;
 		isl_int_sub(bset->ineq[i][0], bset->ineq[i][0], v);
-		if (!tab)
+		if (!ok)
 			goto error;
 	}
 
diff --git a/isl_tab.c b/isl_tab.c
index 348fd09..38a3aef 100644
--- a/isl_tab.c
+++ b/isl_tab.c
@@ -925,17 +925,15 @@ int isl_tab_mark_redundant(struct isl_tab *tab, int row)
 	}
 }
 
-struct isl_tab *isl_tab_mark_empty(struct isl_tab *tab)
+int isl_tab_mark_empty(struct isl_tab *tab)
 {
 	if (!tab)
-		return NULL;
+		return -1;
 	if (!tab->empty && tab->need_undo)
-		if (isl_tab_push(tab, isl_tab_undo_empty) < 0) {
-			isl_tab_free(tab);
-			return NULL;
-		}
+		if (isl_tab_push(tab, isl_tab_undo_empty) < 0)
+			return -1;
 	tab->empty = 1;
-	return tab;
+	return 0;
 }
 
 /* Update the rows signs after a pivot of "row" and "col", with "row_sgn"
@@ -1633,25 +1631,25 @@ static int drop_col(struct isl_tab *tab, int col)
 /* Add inequality "ineq" and check if it conflicts with the
  * previously added constraints or if it is obviously redundant.
  */
-struct isl_tab *isl_tab_add_ineq(struct isl_tab *tab, isl_int *ineq)
+int isl_tab_add_ineq(struct isl_tab *tab, isl_int *ineq)
 {
 	int r;
 	int sgn;
 	isl_int cst;
 
 	if (!tab)
-		return NULL;
+		return -1;
 	if (tab->bset) {
 		struct isl_basic_set *bset = tab->bset;
 
-		isl_assert(tab->mat->ctx, tab->n_eq == bset->n_eq, goto error);
+		isl_assert(tab->mat->ctx, tab->n_eq == bset->n_eq, return -1);
 		isl_assert(tab->mat->ctx,
-			    tab->n_con == bset->n_eq + bset->n_ineq, goto error);
+			    tab->n_con == bset->n_eq + bset->n_ineq, return -1);
 		tab->bset = isl_basic_set_add_ineq(tab->bset, ineq);
 		if (isl_tab_push(tab, isl_tab_undo_bset_ineq) < 0)
-			goto error;
+			return -1;
 		if (!tab->bset)
-			goto error;
+			return -1;
 	}
 	if (tab->cone) {
 		isl_int_init(cst);
@@ -1663,28 +1661,25 @@ struct isl_tab *isl_tab_add_ineq(struct isl_tab *tab, isl_int *ineq)
 		isl_int_clear(cst);
 	}
 	if (r < 0)
-		goto error;
+		return -1;
 	tab->con[r].is_nonneg = 1;
 	if (isl_tab_push_var(tab, isl_tab_undo_nonneg, &tab->con[r]) < 0)
-		goto error;
+		return -1;
 	if (isl_tab_row_is_redundant(tab, tab->con[r].index)) {
 		if (isl_tab_mark_redundant(tab, tab->con[r].index) < 0)
-			goto error;
-		return tab;
+			return -1;
+		return 0;
 	}
 
 	sgn = restore_row(tab, &tab->con[r]);
 	if (sgn < -1)
-		goto error;
+		return -1;
 	if (sgn < 0)
 		return isl_tab_mark_empty(tab);
 	if (tab->con[r].is_row && isl_tab_row_is_redundant(tab, tab->con[r].index))
 		if (isl_tab_mark_redundant(tab, tab->con[r].index) < 0)
-			goto error;
-	return tab;
-error:
-	isl_tab_free(tab);
-	return NULL;
+			return -1;
+	return 0;
 }
 
 /* Pivot a non-negative variable down until it reaches the value zero
@@ -1891,8 +1886,11 @@ struct isl_tab *isl_tab_add_eq(struct isl_tab *tab, isl_int *eq)
 		sgn = sign_of_max(tab, var);
 		if (sgn < -1)
 			goto error;
-		if (sgn < 0)
-			return isl_tab_mark_empty(tab);
+		if (sgn < 0) {
+			if (isl_tab_mark_empty(tab) < 0)
+				goto error;
+			return tab;
+		}
 	}
 
 	var->is_nonneg = 1;
@@ -1921,19 +1919,26 @@ struct isl_tab *isl_tab_from_basic_map(struct isl_basic_map *bmap)
 	if (!tab)
 		return NULL;
 	tab->rational = ISL_F_ISSET(bmap, ISL_BASIC_MAP_RATIONAL);
-	if (ISL_F_ISSET(bmap, ISL_BASIC_MAP_EMPTY))
-		return isl_tab_mark_empty(tab);
+	if (ISL_F_ISSET(bmap, ISL_BASIC_MAP_EMPTY)) {
+		if (isl_tab_mark_empty(tab) < 0)
+			goto error;
+		return tab;
+	}
 	for (i = 0; i < bmap->n_eq; ++i) {
 		tab = add_eq(tab, bmap->eq[i]);
 		if (!tab)
 			return tab;
 	}
 	for (i = 0; i < bmap->n_ineq; ++i) {
-		tab = isl_tab_add_ineq(tab, bmap->ineq[i]);
-		if (!tab || tab->empty)
+		if (isl_tab_add_ineq(tab, bmap->ineq[i]) < 0)
+			goto error;
+		if (tab->empty)
 			return tab;
 	}
 	return tab;
+error:
+	isl_tab_free(tab);
+	return NULL;
 }
 
 struct isl_tab *isl_tab_from_basic_set(struct isl_basic_set *bset)
@@ -2195,8 +2200,11 @@ static struct isl_tab *cut_to_hyperplane(struct isl_tab *tab,
 	sgn = sign_of_max(tab, &tab->con[r]);
 	if (sgn < -1)
 		goto error;
-	if (sgn < 0)
-		return isl_tab_mark_empty(tab);
+	if (sgn < 0) {
+		if (isl_tab_mark_empty(tab) < 0)
+			goto error;
+		return tab;
+	}
 	tab->con[r].is_nonneg = 1;
 	if (isl_tab_push_var(tab, isl_tab_undo_nonneg, &tab->con[r]) < 0)
 		goto error;
diff --git a/isl_tab.h b/isl_tab.h
index 13919cf..9f55e0c 100644
--- a/isl_tab.h
+++ b/isl_tab.h
@@ -179,7 +179,7 @@ enum isl_lp_result isl_tab_min(struct isl_tab *tab,
 	unsigned flags) WARN_UNUSED;
 
 struct isl_tab *isl_tab_extend(struct isl_tab *tab, unsigned n_new) WARN_UNUSED;
-struct isl_tab *isl_tab_add_ineq(struct isl_tab *tab, isl_int *ineq) WARN_UNUSED;
+int isl_tab_add_ineq(struct isl_tab *tab, isl_int *ineq) WARN_UNUSED;
 struct isl_tab *isl_tab_add_eq(struct isl_tab *tab, isl_int *eq) WARN_UNUSED;
 struct isl_tab *isl_tab_add_valid_eq(struct isl_tab *tab, isl_int *eq) WARN_UNUSED;
 
@@ -216,7 +216,7 @@ struct isl_map *isl_tab_basic_map_partial_lexopt(
 
 struct isl_tab_var *isl_tab_var_from_row(struct isl_tab *tab, int i);
 int isl_tab_mark_redundant(struct isl_tab *tab, int row) WARN_UNUSED;
-struct isl_tab *isl_tab_mark_empty(struct isl_tab *tab);
+int isl_tab_mark_empty(struct isl_tab *tab) WARN_UNUSED;
 struct isl_tab *isl_tab_dup(struct isl_tab *tab);
 struct isl_tab *isl_tab_product(struct isl_tab *tab1, struct isl_tab *tab2);
 int isl_tab_extend_cons(struct isl_tab *tab, unsigned n_new) WARN_UNUSED;
diff --git a/isl_tab_pip.c b/isl_tab_pip.c
index 4758106..8f3311c 100644
--- a/isl_tab_pip.c
+++ b/isl_tab_pip.c
@@ -1100,8 +1100,11 @@ static struct isl_tab *restore_lexmin(struct isl_tab *tab)
 		return tab;
 	while ((row = first_neg(tab)) != -1) {
 		col = lexmin_pivot_col(tab, row);
-		if (col >= tab->n_col)
-			return isl_tab_mark_empty(tab);
+		if (col >= tab->n_col) {
+			if (isl_tab_mark_empty(tab) < 0)
+				goto error;
+			return tab;
+		}
 		if (col < 0)
 			goto error;
 		if (isl_tab_pivot(tab, row, col) < 0)
@@ -1243,8 +1246,11 @@ static struct isl_tab *add_lexmin_eq(struct isl_tab *tab, isl_int *eq)
 	row = tab->con[r1].index;
 	if (is_constant(tab, row)) {
 		if (!isl_int_is_zero(tab->mat->row[row][1]) ||
-		    (tab->M && !isl_int_is_zero(tab->mat->row[row][2])))
-			return isl_tab_mark_empty(tab);
+		    (tab->M && !isl_int_is_zero(tab->mat->row[row][2]))) {
+			if (isl_tab_mark_empty(tab) < 0)
+				goto error;
+			return tab;
+		}
 		if (isl_tab_rollback(tab, snap) < 0)
 			goto error;
 		return tab;
@@ -1515,8 +1521,11 @@ static struct isl_tab *cut_to_integer_lexmin(struct isl_tab *tab)
 		return tab;
 
 	while ((row = first_non_integer(tab, &flags)) != -1) {
-		if (ISL_FL_ISSET(flags, I_VAR))
-			return isl_tab_mark_empty(tab);
+		if (ISL_FL_ISSET(flags, I_VAR)) {
+			if (isl_tab_mark_empty(tab) < 0)
+				goto error;
+			return tab;
+		}
 		row = add_cut(tab, row);
 		if (row < 0)
 			goto error;
@@ -1979,8 +1988,11 @@ static struct isl_tab *tab_for_lexmin(struct isl_basic_map *bmap,
 		if (!tab->row_sign)
 			goto error;
 	}
-	if (ISL_F_ISSET(bmap, ISL_BASIC_MAP_EMPTY))
-		return isl_tab_mark_empty(tab);
+	if (ISL_F_ISSET(bmap, ISL_BASIC_MAP_EMPTY)) {
+		if (isl_tab_mark_empty(tab) < 0)
+			goto error;
+		return tab;
+	}
 
 	for (i = tab->n_param; i < tab->n_var - tab->n_div; ++i) {
 		tab->var[i].is_nonneg = 1;
@@ -2051,6 +2063,7 @@ static int best_split(struct isl_tab *tab, struct isl_tab *context_tab)
 		struct isl_tab_undo *snap2;
 		struct isl_vec *ineq = NULL;
 		int r = 0;
+		int ok;
 
 		if (!isl_tab_var_from_row(tab, split)->is_nonneg)
 			continue;
@@ -2060,8 +2073,10 @@ static int best_split(struct isl_tab *tab, struct isl_tab *context_tab)
 		ineq = get_row_parameter_ineq(tab, split);
 		if (!ineq)
 			return -1;
-		context_tab = isl_tab_add_ineq(context_tab, ineq->el);
+		ok = isl_tab_add_ineq(context_tab, ineq->el) >= 0;
 		isl_vec_free(ineq);
+		if (!ok)
+			return -1;
 
 		snap2 = isl_tab_snap(context_tab);
 
@@ -2078,8 +2093,10 @@ static int best_split(struct isl_tab *tab, struct isl_tab *context_tab)
 			ineq = get_row_parameter_ineq(tab, row);
 			if (!ineq)
 				return -1;
-			context_tab = isl_tab_add_ineq(context_tab, ineq->el);
+			ok = isl_tab_add_ineq(context_tab, ineq->el) >= 0;
 			isl_vec_free(ineq);
+			if (!ok)
+				return -1;
 			var = &context_tab->con[context_tab->n_con - 1];
 			if (!context_tab->empty &&
 			    !isl_tab_min_at_most_neg_one(context_tab, var))
@@ -2347,7 +2364,8 @@ static struct isl_tab *tab_detect_nonnegative_parameters(struct isl_tab *tab,
 	isl_seq_clr(ineq->el, ineq->size);
 	for (i = 0; i < context_tab->n_var; ++i) {
 		isl_int_set_si(ineq->el[1 + i], 1);
-		context_tab = isl_tab_add_ineq(context_tab, ineq->el);
+		if (isl_tab_add_ineq(context_tab, ineq->el) < 0)
+			goto error;
 		var = &context_tab->con[context_tab->n_con - 1];
 		if (!context_tab->empty &&
 		    !isl_tab_min_at_most_neg_one(context_tab, var)) {
@@ -2663,7 +2681,8 @@ static void check_gbr_integer_feasible(struct isl_context_gbr *cgbr)
 
 	if (sample->size == 0) {
 		isl_vec_free(sample);
-		cgbr->tab = isl_tab_mark_empty(cgbr->tab);
+		if (isl_tab_mark_empty(cgbr->tab) < 0)
+			goto error;
 		return;
 	}
 
@@ -2729,7 +2748,8 @@ static void add_gbr_ineq(struct isl_context_gbr *cgbr, isl_int *ineq)
 	if (isl_tab_extend_cons(cgbr->tab, 1) < 0)
 		goto error;
 
-	cgbr->tab = isl_tab_add_ineq(cgbr->tab, ineq);
+	if (isl_tab_add_ineq(cgbr->tab, ineq) < 0)
+		goto error;
 
 	if (cgbr->shifted && !cgbr->shifted->empty && use_shifted(cgbr)) {
 		int i;
@@ -2745,7 +2765,8 @@ static void add_gbr_ineq(struct isl_context_gbr *cgbr, isl_int *ineq)
 			isl_int_add(ineq[0], ineq[0], ineq[1 + i]);
 		}
 
-		cgbr->shifted = isl_tab_add_ineq(cgbr->shifted, ineq);
+		if (isl_tab_add_ineq(cgbr->shifted, ineq) < 0)
+			goto error;
 
 		for (i = 0; i < dim; ++i) {
 			if (!isl_int_is_neg(ineq[1 + i]))
@@ -2757,7 +2778,8 @@ static void add_gbr_ineq(struct isl_context_gbr *cgbr, isl_int *ineq)
 	if (cgbr->cone && cgbr->cone->n_col != cgbr->cone->n_dead) {
 		if (isl_tab_extend_cons(cgbr->cone, 1) < 0)
 			goto error;
-		cgbr->cone = isl_tab_add_ineq(cgbr->cone, ineq);
+		if (isl_tab_add_ineq(cgbr->cone, ineq) < 0)
+			goto error;
 	}
 
 	return;
@@ -3636,7 +3658,8 @@ static void find_solutions(struct isl_sol *sol, struct isl_tab *tab)
 			break;
 		if (ISL_FL_ISSET(flags, I_PAR)) {
 			if (ISL_FL_ISSET(flags, I_VAR)) {
-				tab = isl_tab_mark_empty(tab);
+				if (isl_tab_mark_empty(tab) < 0)
+					goto error;
 				break;
 			}
 			row = add_cut(tab, row);
-- 
2.7.4