From 203764eb51ba0bfb0ac3ea96d23c9e9dc566bc12 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@pdimov.com>
Date: Wed, 19 Apr 2006 21:03:18 +0000
Subject: [PATCH] Fix VC6 codegen issue (Alain Cormier)

[SVN r33747]
---
 include/boost/detail/sp_counted_base_w32.hpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/include/boost/detail/sp_counted_base_w32.hpp b/include/boost/detail/sp_counted_base_w32.hpp
index e84f06e..fb42c4e 100644
--- a/include/boost/detail/sp_counted_base_w32.hpp
+++ b/include/boost/detail/sp_counted_base_w32.hpp
@@ -25,6 +25,7 @@
 //
 
 #include <boost/detail/interlocked.hpp>
+#include <boost/detail/workaround.hpp>
 #include <typeinfo>
 
 namespace boost
@@ -78,7 +79,19 @@ public:
         {
             long tmp = static_cast< long const volatile& >( use_count_ );
             if( tmp == 0 ) return false;
+
+#if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, == 1200 )
+
+            // work around a code generation bug
+
+            long tmp2 = tmp + 1;
+            if( BOOST_INTERLOCKED_COMPARE_EXCHANGE( &use_count_, tmp2, tmp ) == tmp2 - 1 ) return true;
+
+#else
+
             if( BOOST_INTERLOCKED_COMPARE_EXCHANGE( &use_count_, tmp + 1, tmp ) == tmp ) return true;
+
+#endif
         }
     }