From 03bc645a01155b1e5e11e017c2816f533dedefb3 Mon Sep 17 00:00:00 2001
From: Sven Verdoolaege <skimo@kotnet.org>
Date: Sat, 24 Aug 2013 14:09:49 +0200
Subject: [PATCH] add isl_val_inv

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>
---
 doc/user.pod      |  1 +
 include/isl/val.h |  1 +
 isl_test.c        |  9 +++++++++
 isl_val.c         | 27 +++++++++++++++++++++++++++
 4 files changed, 38 insertions(+)

diff --git a/doc/user.pod b/doc/user.pod
index 1995bf28..8f50f46a 100644
--- a/doc/user.pod
+++ b/doc/user.pod
@@ -656,6 +656,7 @@ The following unary operations are available on C<isl_val>s.
 	__isl_give isl_val *isl_val_floor(__isl_take isl_val *v);
 	__isl_give isl_val *isl_val_ceil(__isl_take isl_val *v);
 	__isl_give isl_val *isl_val_trunc(__isl_take isl_val *v);
+	__isl_give isl_val *isl_val_inv(__isl_take isl_val *v);
 	__isl_give isl_val *isl_val_2exp(__isl_take isl_val *v);
 
 The following binary operations are available on C<isl_val>s.
diff --git a/include/isl/val.h b/include/isl/val.h
index 2a0dd92a..238f0c28 100644
--- a/include/isl/val.h
+++ b/include/isl/val.h
@@ -46,6 +46,7 @@ __isl_give isl_val *isl_val_set_si(__isl_take isl_val *v, long i);
 
 __isl_give isl_val *isl_val_abs(__isl_take isl_val *v);
 __isl_give isl_val *isl_val_neg(__isl_take isl_val *v);
+__isl_give isl_val *isl_val_inv(__isl_take isl_val *v);
 __isl_give isl_val *isl_val_floor(__isl_take isl_val *v);
 __isl_give isl_val *isl_val_ceil(__isl_take isl_val *v);
 __isl_give isl_val *isl_val_trunc(__isl_take isl_val *v);
diff --git a/isl_test.c b/isl_test.c
index c4d5329a..cb9075ad 100644
--- a/isl_test.c
+++ b/isl_test.c
@@ -409,6 +409,15 @@ struct {
 	{ &isl_val_2exp, "1", "2" },
 	{ &isl_val_2exp, "2", "4" },
 	{ &isl_val_2exp, "3", "8" },
+	{ &isl_val_inv, "1", "1" },
+	{ &isl_val_inv, "2", "1/2" },
+	{ &isl_val_inv, "1/2", "2" },
+	{ &isl_val_inv, "-2", "-1/2" },
+	{ &isl_val_inv, "-1/2", "-2" },
+	{ &isl_val_inv, "0", "NaN" },
+	{ &isl_val_inv, "NaN", "NaN" },
+	{ &isl_val_inv, "infty", "0" },
+	{ &isl_val_inv, "-infty", "0" },
 };
 
 /* Perform some basic tests of unary operations on isl_val objects.
diff --git a/isl_val.c b/isl_val.c
index 00e7a0d0..4938c4c3 100644
--- a/isl_val.c
+++ b/isl_val.c
@@ -393,6 +393,33 @@ __isl_give isl_val *isl_val_neg(__isl_take isl_val *v)
 	return v;
 }
 
+/* Return the inverse of "v".
+ */
+__isl_give isl_val *isl_val_inv(__isl_take isl_val *v)
+{
+	if (!v)
+		return NULL;
+	if (isl_val_is_nan(v))
+		return v;
+	if (isl_val_is_zero(v)) {
+		isl_ctx *ctx = isl_val_get_ctx(v);
+		isl_val_free(v);
+		return isl_val_nan(ctx);
+	}
+	if (isl_val_is_infty(v) || isl_val_is_neginfty(v)) {
+		isl_ctx *ctx = isl_val_get_ctx(v);
+		isl_val_free(v);
+		return isl_val_zero(ctx);
+	}
+
+	v = isl_val_cow(v);
+	if (!v)
+		return NULL;
+	isl_int_swap(v->n, v->d);
+
+	return isl_val_normalize(v);
+}
+
 /* Return the absolute value of "v".
  */
 __isl_give isl_val *isl_val_abs(__isl_take isl_val *v)
-- 
2.11.4.GIT