From 197465bb20307c3df2781e89a03afab431d17364 Mon Sep 17 00:00:00 2001
From: Sven Verdoolaege <skimo@kotnet.org>
Date: Tue, 14 Oct 2014 12:53:43 +0200
Subject: [PATCH] add isl_basic_map_shift_div

We will need this to shift some integer divisions in one basic map
to align them with integer divisions in another basic map during coalescing.

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>
---
 isl_map_private.h  |  3 +++
 isl_map_simplify.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/isl_map_private.h b/isl_map_private.h
index adbd8a2d..a424ef99 100644
--- a/isl_map_private.h
+++ b/isl_map_private.h
@@ -407,6 +407,9 @@ int isl_basic_map_output_defining_equality(__isl_keep isl_basic_map *bmap,
 __isl_give isl_basic_map *isl_basic_map_reduce_coefficients(
 	__isl_take isl_basic_map *bmap);
 
+__isl_give isl_basic_map *isl_basic_map_shift_div(
+	__isl_take isl_basic_map *bmap, int div, isl_int shift);
+
 __isl_give isl_basic_map_list *isl_map_get_basic_map_list(
 	__isl_keep isl_map *map);
 
diff --git a/isl_map_simplify.c b/isl_map_simplify.c
index 6d6c798c..fdde7308 100644
--- a/isl_map_simplify.c
+++ b/isl_map_simplify.c
@@ -3470,3 +3470,51 @@ error:
 	isl_vec_free(v);
 	return isl_basic_map_free(bmap);
 }
+
+/* Shift the integer division at position "div" of "bmap" by "shift".
+ *
+ * That is, if the integer division has the form
+ *
+ *	floor(f(x)/d)
+ *
+ * then replace it by
+ *
+ *	floor((f(x) + shift * d)/d) - shift
+ */
+__isl_give isl_basic_map *isl_basic_map_shift_div(
+	__isl_take isl_basic_map *bmap, int div, isl_int shift)
+{
+	int i;
+	unsigned total;
+
+	if (!bmap)
+		return NULL;
+
+	total = isl_basic_map_dim(bmap, isl_dim_all);
+	total -= isl_basic_map_dim(bmap, isl_dim_div);
+
+	isl_int_addmul(bmap->div[div][1], shift, bmap->div[div][0]);
+
+	for (i = 0; i < bmap->n_eq; ++i) {
+		if (isl_int_is_zero(bmap->eq[i][1 + total + div]))
+			continue;
+		isl_int_submul(bmap->eq[i][0],
+				shift, bmap->eq[i][1 + total + div]);
+	}
+	for (i = 0; i < bmap->n_ineq; ++i) {
+		if (isl_int_is_zero(bmap->ineq[i][1 + total + div]))
+			continue;
+		isl_int_submul(bmap->ineq[i][0],
+				shift, bmap->ineq[i][1 + total + div]);
+	}
+	for (i = 0; i < bmap->n_div; ++i) {
+		if (isl_int_is_zero(bmap->div[i][0]))
+			continue;
+		if (isl_int_is_zero(bmap->div[i][1 + 1 + total + div]))
+			continue;
+		isl_int_submul(bmap->div[i][1],
+				shift, bmap->div[i][1 + 1 + total + div]);
+	}
+
+	return bmap;
+}
-- 
2.11.4.GIT