X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=isl_tab_pip.c;h=dd95d885e1431b122fc029a0e9154ba9a790d170;hb=fdf9c99e27483b8c1c4938072119cd8b7c2a4a37;hp=476433440b92f7a2196dea32c20609dcc378c697;hpb=8f52ea51fa97d17c112722a67109410eef78bd93;p=platform%2Fupstream%2Fisl.git

diff --git a/isl_tab_pip.c b/isl_tab_pip.c
index 4764334..dd95d88 100644
--- a/isl_tab_pip.c
+++ b/isl_tab_pip.c
@@ -745,6 +745,30 @@ static struct isl_vec *get_row_parameter_ineq(struct isl_tab *tab, int row)
 	return ineq;
 }
 
+/* Normalize a div expression of the form
+ *
+ *	[(g*f(x) + c)/(g * m)]
+ *
+ * with c the constant term and f(x) the remaining coefficients, to
+ *
+ *	[(f(x) + [c/g])/m]
+ */
+static void normalize_div(__isl_keep isl_vec *div)
+{
+	isl_ctx *ctx = isl_vec_get_ctx(div);
+	int len = div->size - 2;
+
+	isl_seq_gcd(div->el + 2, len, &ctx->normalize_gcd);
+	isl_int_gcd(ctx->normalize_gcd, ctx->normalize_gcd, div->el[0]);
+
+	if (isl_int_is_one(ctx->normalize_gcd))
+		return;
+
+	isl_int_divexact(div->el[0], div->el[0], ctx->normalize_gcd);
+	isl_int_fdiv_q(div->el[1], div->el[1], ctx->normalize_gcd);
+	isl_seq_scale_down(div->el + 2, div->el + 2, ctx->normalize_gcd, len);
+}
+
 /* Return a integer division for use in a parametric cut based on the given row.
  * In particular, let the parametric constant of the row be
  *
@@ -765,8 +789,8 @@ static struct isl_vec *get_row_parameter_div(struct isl_tab *tab, int row)
 
 	isl_int_set(div->el[0], tab->mat->row[row][0]);
 	get_row_parameter_line(tab, row, div->el + 1);
-	div = isl_vec_normalize(div);
 	isl_seq_neg(div->el + 1, div->el + 1, div->size - 1);
+	normalize_div(div);
 	isl_seq_fdiv_r(div->el + 1, div->el + 1, div->el[0], div->size - 1);
 
 	return div;
@@ -793,7 +817,7 @@ static struct isl_vec *get_row_split_div(struct isl_tab *tab, int row)
 
 	isl_int_set(div->el[0], tab->mat->row[row][0]);
 	get_row_parameter_line(tab, row, div->el + 1);
-	div = isl_vec_normalize(div);
+	normalize_div(div);
 	isl_seq_fdiv_r(div->el + 1, div->el + 1, div->el[0], div->size - 1);
 
 	return div;
@@ -1153,8 +1177,8 @@ static int report_conflicting_constraint(struct isl_tab *tab, int con)
 
 /* Given a conflicting row in the tableau, report all constraints
  * involved in the row to the caller.  That is, the row itself
- * (if represents a constraint) and all constraint columns with
- * non-zero (and therefore negative) coefficient.
+ * (if it represents a constraint) and all constraint columns with
+ * non-zero (and therefore negative) coefficients.
  */
 static int report_conflict(struct isl_tab *tab, int row)
 {
@@ -1606,6 +1630,9 @@ static int add_cut(struct isl_tab *tab, int row)
 	return tab->con[r].index;
 }
 
+#define CUT_ALL 1
+#define CUT_ONE 0
+
 /* Given a non-parametric tableau, add cuts until an integer
  * sample point is obtained or until the tableau is determined
  * to be integer infeasible.
@@ -1617,8 +1644,12 @@ static int add_cut(struct isl_tab *tab, int row)
  * combination of variables/constraints plus a non-integral constant,
  * then there is no way to obtain an integer point and we return
  * a tableau that is marked empty.
+ * The parameter cutting_strategy controls the strategy used when adding cuts
+ * to remove non-integer points. CUT_ALL adds all possible cuts
+ * before continuing the search. CUT_ONE adds only one cut at a time.
  */
-static struct isl_tab *cut_to_integer_lexmin(struct isl_tab *tab)
+static struct isl_tab *cut_to_integer_lexmin(struct isl_tab *tab,
+	int cutting_strategy)
 {
 	int var;
 	int row;
@@ -1640,6 +1671,8 @@ static struct isl_tab *cut_to_integer_lexmin(struct isl_tab *tab)
 			row = add_cut(tab, row);
 			if (row < 0)
 				goto error;
+			if (cutting_strategy == CUT_ONE)
+				break;
 		} while ((var = next_non_integer_var(tab, var, &flags)) != -1);
 		if (restore_lexmin(tab) < 0)
 			goto error;
@@ -1730,7 +1763,7 @@ static struct isl_tab *check_integer_feasible(struct isl_tab *tab)
 	if (isl_tab_push_basis(tab) < 0)
 		goto error;
 
-	tab = cut_to_integer_lexmin(tab);
+	tab = cut_to_integer_lexmin(tab, CUT_ALL);
 	if (!tab)
 		goto error;
 
@@ -4958,7 +4991,7 @@ __isl_give isl_vec *isl_tab_basic_set_non_trivial_lexmin(
 		int side, base;
 
 		if (init) {
-			tab = cut_to_integer_lexmin(tab);
+			tab = cut_to_integer_lexmin(tab, CUT_ONE);
 			if (!tab)
 				goto error;
 			if (tab->empty)