From f5287a50d04eeb22317ba8ab90f295b0bc3c5d56 Mon Sep 17 00:00:00 2001
From: Sven Verdoolaege <skimo@kotnet.org>
Date: Thu, 19 Jul 2012 21:27:28 +0200
Subject: [PATCH] extract out common isl_seq_substitute

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>
---
 isl_aff.c         | 37 ++++++++++++++++++++++++++++++++-----
 isl_aff_private.h |  3 +++
 isl_local_space.c |  9 ++-------
 3 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/isl_aff.c b/isl_aff.c
index 40b925f..5a0483a 100644
--- a/isl_aff.c
+++ b/isl_aff.c
@@ -648,6 +648,36 @@ __isl_give isl_aff *isl_aff_remove_unused_divs( __isl_take isl_aff *aff)
 	return aff;
 }
 
+/* Given two affine expressions "p" of length p_len (including the
+ * denominator and the constant term) and "subs" of length subs_len,
+ * plug in "subs" for the variable at position "pos".
+ * The variables of "subs" and "p" are assumed to match up to subs_len,
+ * but "p" may have additional variables.
+ * "v" is an initialized isl_int that can be used internally.
+ *
+ * In particular, if "p" represents the expression
+ *
+ *	(a i + g)/m
+ *
+ * with i the variable at position "pos" and "subs" represents the expression
+ *
+ *	f/d
+ *
+ * then the result represents the expression
+ *
+ *	(a f + d g)/(m d)
+ *
+ */
+void isl_seq_substitute(isl_int *p, int pos, isl_int *subs,
+	int p_len, int subs_len, isl_int v)
+{
+	isl_int_set(v, p[1 + pos]);
+	isl_int_set_si(p[1 + pos], 0);
+	isl_seq_combine(p + 1, subs[0], p + 1, v, subs + 1, subs_len - 1);
+	isl_seq_scale(p + subs_len, p + subs_len, subs[0], p_len - subs_len);
+	isl_int_mul(p[0], p[0], subs[0]);
+}
+
 /* Swap divs "a" and "b" in "aff", which is assumed to be non-NULL.
  *
  * Even though this function is only called on isl_affs with a single
@@ -3089,11 +3119,8 @@ __isl_give isl_aff *isl_aff_substitute(__isl_take isl_aff *aff,
 	pos += isl_local_space_offset(aff->ls, type);
 
 	isl_int_init(v);
-	isl_int_set(v, aff->v->el[1 + pos]);
-	isl_int_set_si(aff->v->el[1 + pos], 0);
-	isl_seq_combine(aff->v->el + 1, subs->v->el[0], aff->v->el + 1,
-			v, subs->v->el + 1, subs->v->size - 1);
-	isl_int_mul(aff->v->el[0], aff->v->el[0], subs->v->el[0]);
+	isl_seq_substitute(aff->v->el, pos, subs->v->el,
+			    aff->v->size, subs->v->size, v);
 	isl_int_clear(v);
 
 	return aff;
diff --git a/isl_aff_private.h b/isl_aff_private.h
index 14d5bf0..06ee1eb 100644
--- a/isl_aff_private.h
+++ b/isl_aff_private.h
@@ -92,6 +92,9 @@ __isl_give isl_pw_multi_aff *isl_pw_multi_aff_project_out(
 	__isl_take isl_pw_multi_aff *pma,
 	enum isl_dim_type type, unsigned first, unsigned n);
 
+void isl_seq_substitute(isl_int *p, int pos, isl_int *subs,
+	int p_len, int subs_len, isl_int v);
+
 __isl_give isl_pw_multi_aff *isl_pw_multi_aff_substitute(
 	__isl_take isl_pw_multi_aff *pma, enum isl_dim_type type, unsigned pos,
 	__isl_keep isl_pw_aff *subs);
diff --git a/isl_local_space.c b/isl_local_space.c
index 0759b13..64b6b33 100644
--- a/isl_local_space.c
+++ b/isl_local_space.c
@@ -790,13 +790,8 @@ __isl_give isl_local_space *isl_local_space_substitute(
 	for (i = 0; i < ls->div->n_row; ++i) {
 		if (isl_int_is_zero(ls->div->row[i][1 + pos]))
 			continue;
-		isl_int_set(v, ls->div->row[i][1 + pos]);
-		isl_int_set_si(ls->div->row[i][1 + pos], 0);
-		isl_seq_combine(ls->div->row[i] + 1,
-				subs->v->el[0], ls->div->row[i] + 1,
-				v, subs->v->el + 1, subs->v->size - 1);
-		isl_int_mul(ls->div->row[i][0],
-			    ls->div->row[i][0], subs->v->el[0]);
+		isl_seq_substitute(ls->div->row[i], pos, subs->v->el,
+			subs->v->size, subs->v->size, v);
 		normalize_div(ls, i);
 	}
 	isl_int_clear(v);
-- 
2.7.4