From f8b3c08fd7a5aabe7471c4dfb635d134ee4d8ef3 Mon Sep 17 00:00:00 2001
From: Richard Kreckel <kreckel@ginac.de>
Date: Sun, 20 Dec 2015 17:30:34 +0100
Subject: [PATCH] Remove iter_swap specializations.

It's a myth that iter_swap helps the compiler produce better code.
Let's just use specialized swap instead.
---
 ginac/ex.h     | 14 --------------
 ginac/expair.h |  4 ----
 ginac/utils.h  |  5 +++--
 3 files changed, 3 insertions(+), 20 deletions(-)

diff --git a/ginac/ex.h b/ginac/ex.h
index 6fd45c9d..db78536b 100644
--- a/ginac/ex.h
+++ b/ginac/ex.h
@@ -970,20 +970,6 @@ inline void swap(GiNaC::ex &a, GiNaC::ex &b)
 	a.swap(b);
 }
 
-/** Specialization of std::iter_swap() for vector<ex> iterators. */
-template <>
-inline void iter_swap(vector<GiNaC::ex>::iterator i1, vector<GiNaC::ex>::iterator i2)
-{
-	i1->swap(*i2);
-}
-
-/** Specialization of std::iter_swap() for list<ex> iterators. */
-template <>
-inline void iter_swap(list<GiNaC::ex>::iterator i1, list<GiNaC::ex>::iterator i2)
-{
-	i1->swap(*i2);
-}
-
 } // namespace std
 
 #endif // ndef GINAC_EX_H
diff --git a/ginac/expair.h b/ginac/expair.h
index 3be5a03e..ea26b53d 100644
--- a/ginac/expair.h
+++ b/ginac/expair.h
@@ -111,10 +111,6 @@ struct expair_swap : public std::binary_function<expair, expair, void> {
 inline void swap(expair & e1, expair & e2)
 { e1.swap(e2); }
 
-// This makes STL algorithms use the more efficient swap operation for ex objects
-inline void iter_swap(std::vector<expair>::iterator i1, std::vector<expair>::iterator i2)
-{ i1->swap(*i2); }
-
 } // namespace GiNaC
 
 #endif // ndef GINAC_EXPAIR_H
diff --git a/ginac/utils.h b/ginac/utils.h
index 042f14cb..692c7314 100644
--- a/ginac/utils.h
+++ b/ginac/utils.h
@@ -108,6 +108,7 @@ inline unsigned golden_ratio_hash(p_int n)
 template <class It>
 int permutation_sign(It first, It last)
 {
+	using std::swap;
 	if (first == last)
 		return 0;
 	--last;
@@ -122,7 +123,7 @@ int permutation_sign(It first, It last)
 		bool swapped = false;
 		while (i != first) {
 			if (*i < *other) {
-				std::iter_swap(other, i);
+				swap(*other, *i);
 				flag = other;
 				swapped = true;
 				sign = -sign;
@@ -143,7 +144,7 @@ int permutation_sign(It first, It last)
 		swapped = false;
 		while (i != last) {
 			if (*other < *i) {
-				std::iter_swap(i, other);
+				swap(*i, *other);
 				flag = other;
 				swapped = true;
 				sign = -sign;
-- 
2.47.0