From 9c01326d9a6d56c381ef139a2c25953f483feec8 Mon Sep 17 00:00:00 2001
From: Richard Guenther <rguenther@suse.de>
Date: Sun, 4 Jan 2009 19:51:18 +0000
Subject: re PR libstdc++/38720 (_Relative_pointer_impl invokes undefined
 behavior)

2009-01-04  Richard Guenther  <rguenther@suse.de>

	PR libstdc++/38720
	* include/ext/pointer.h (_Relative_pointer_impl): Use an unsigned
	integer type for storage, arithmetic and comparisons.
	* testsuite/ext/ext_pointer/1_neg.cc: Adjust line numbers.

From-SVN: r143058
---
 libstdc++-v3/include/ext/pointer.h | 40 ++++++++++++++++++++++++--------------
 1 file changed, 25 insertions(+), 15 deletions(-)

(limited to 'libstdc++-v3/include/ext/pointer.h')

diff --git a/libstdc++-v3/include/ext/pointer.h b/libstdc++-v3/include/ext/pointer.h
index 5c764cf..ff409b6 100644
--- a/libstdc++-v3/include/ext/pointer.h
+++ b/libstdc++-v3/include/ext/pointer.h
@@ -42,6 +42,7 @@
 #include <iosfwd>
 #include <bits/stl_iterator_base_types.h>
 #include <ext/cast.h>
+#include <ext/type_traits.h>
 
 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
 
@@ -111,9 +112,8 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
         if (_M_diff == 1)
           return 0;
         else
-          return reinterpret_cast<_Tp*>(
-                 const_cast<char*>(reinterpret_cast<const char*>(this))
-                 + _M_diff);
+          return reinterpret_cast<_Tp*>(reinterpret_cast<_UIntPtrType>(this)
+					+ _M_diff);
       }
   
       void 
@@ -122,21 +122,26 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
         if (!__arg)
           _M_diff = 1;
         else
-          _M_diff = reinterpret_cast<char*>(__arg) 
-                    - reinterpret_cast<char*>(this);
+          _M_diff = reinterpret_cast<_UIntPtrType>(__arg) 
+                    - reinterpret_cast<_UIntPtrType>(this);
       }
   
       // Comparison of pointers
       inline bool
       operator<(const _Relative_pointer_impl& __rarg) const
-      { return (this->get() < __rarg.get()); }
+      { return (reinterpret_cast<_UIntPtrType>(this->get())
+		< reinterpret_cast<_UIntPtrType>(__rarg.get())); }
 
       inline bool
       operator==(const _Relative_pointer_impl& __rarg) const
-      { return (this->get() == __rarg.get()); }
+      { return (reinterpret_cast<_UIntPtrType>(this->get())
+		== reinterpret_cast<_UIntPtrType>(__rarg.get())); }
 
     private:
-      std::ptrdiff_t _M_diff;
+      typedef __gnu_cxx::__conditional_type<
+	 (sizeof(unsigned long) >= sizeof(void*)),
+	 unsigned long, unsigned long long>::__type _UIntPtrType;
+      _UIntPtrType _M_diff;
     };
   
   /**
@@ -155,8 +160,8 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
         if (_M_diff == 1)
           return 0;
         else
-          return reinterpret_cast<const _Tp*>(
-                  (reinterpret_cast<const char*>(this)) + _M_diff);
+          return reinterpret_cast<const _Tp*>
+	      (reinterpret_cast<_UIntPtrType>(this) + _M_diff);
       }
   
       void 
@@ -165,21 +170,26 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
         if (!__arg)
           _M_diff = 1;
         else
-          _M_diff = reinterpret_cast<const char*>(__arg) 
-                    - reinterpret_cast<const char*>(this);
+          _M_diff = reinterpret_cast<_UIntPtrType>(__arg) 
+                    - reinterpret_cast<_UIntPtrType>(this);
       }
   
       // Comparison of pointers
       inline bool
       operator<(const _Relative_pointer_impl& __rarg) const
-      { return (this->get() < __rarg.get()); }
+      { return (reinterpret_cast<_UIntPtrType>(this->get())
+		< reinterpret_cast<_UIntPtrType>(__rarg.get())); }
 
       inline bool
       operator==(const _Relative_pointer_impl& __rarg) const
-      { return (this->get() == __rarg.get()); }
+      { return (reinterpret_cast<_UIntPtrType>(this->get())
+		== reinterpret_cast<_UIntPtrType>(__rarg.get())); }
   
     private:
-      std::ptrdiff_t _M_diff;
+      typedef __gnu_cxx::__conditional_type
+	<(sizeof(unsigned long) >= sizeof(void*)),
+	 unsigned long, unsigned long long>::__type _UIntPtrType;
+      _UIntPtrType _M_diff;
     };
 
   /**
-- 
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