From 8f0396e443f24c859a78bfccbb3dbb78aece036c Mon Sep 17 00:00:00 2001
From: Sean Hunt <scshunt@csclub.uwaterloo.ca>
Date: Sat, 30 Jul 2011 00:47:53 +0000
Subject: [PATCH] Add the missing default argument for the allocator and use a
 cleaner implementation of previous().

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@136547 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/ext/slist | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

diff --git a/include/ext/slist b/include/ext/slist
index ef115b3d..30ba7e30 100644
--- a/include/ext/slist
+++ b/include/ext/slist
@@ -21,7 +21,7 @@ namespace __gnu_cxx {
 
 using namespace std;
 
-template <class _Tp, class _Alloc>
+template <class _Tp, class _Alloc = allocator<_Tp> >
 class _LIBCPP_VISIBLE slist : forward_list<_Tp, _Alloc>
 {
 public:
@@ -105,12 +105,9 @@ template <class _Tp, class _Alloc>
 inline _LIBCPP_INLINE_VISIBILITY
 typename slist<_Tp, _Alloc>::iterator slist<_Tp, _Alloc>::previous(iterator __pos)
 {
-  iterator __a = begin(), __b = end();
-  while (__a != __pos)
-  {
-    __b = __a;
-    ++__a;
-  }
+  iterator __a = begin(), __b = begin();
+  while (++__a != __pos)
+    ++__b;
   return __b;
 }
 
@@ -118,12 +115,9 @@ template <class _Tp, class _Alloc>
 inline _LIBCPP_INLINE_VISIBILITY
 typename slist<_Tp, _Alloc>::const_iterator slist<_Tp, _Alloc>::previous(const_iterator __pos)
 {
-  iterator __a = begin(), __b = end();
-  while (__a != __pos)
-  {
-    __b = __a;
-    ++__a;
-  }
+  iterator __a = begin(), __b = begin();
+  while (++__a != __pos)
+    ++__b;
   return __b;
 }