libstdc++/6886: bit vector iterator uses wrong 1 constant

libstdc++/6886: bit vector iterator uses wrong 1 constant

[meissner]

>Number:         6886
>Category:       libstdc++
>Synopsis:       bit vector iterator uses wrong 1 constant
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri May 31 05:16:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Marcus Meissner <meissner@suse.de>
>Release:        3.1 20020410 (prerelease)
>Organization:
SuSE Linux AG
>Environment:
System: Linux gershwin 2.4.18-SMP #1 SMP Mon May 13 09:48:57 UTC 2002 x86_64 unknown
Architecture: x86_64

host: x86_64-unknown-linux-gnu
build: x86_64-unknown-linux-gnu
target: x86_64-unknown-linux-gnu
configured with: /home/hammer/gcc/configure --prefix=/usr --host=x86_64-unknown-linux --build=x86_64-unknown-linux --libdir=/usr/lib64 --enable-languages=c,c++ --enable-threads=posix --disable-nls
>Description:


The stl bitvector implementation contains in both the iterator and
const_iterator implementation the code:

  reference operator*() const { return reference(_M_p, 1U << _M_offset); }

Since the bit_type is an unsigned long, it should be 1UL here.

I have attached a testcase exhibiting the problem and a fix in 
the Fix section.

Ciao, Marcus

>How-To-Repeat:

#include <assert.h>
#include <vector>

typedef std::vector<bool> bvec;

int
main() {
	int	i, num = 0;

	bvec v;

	v.resize(66);

	for (i = 0 ; i < 66 ; i++)
		v[i] = 0;

	v[1]	= 1;
	v[33]	= 1;
	v[49]	= 1;
	v[65]	= 1;

	for (bvec::iterator j = v.begin() ; j < v.end() ; j++) {
		if (bool(*j)) num++;
	}
	assert (num == 4);
	return 0;
}

>Fix:

--- libstdc++-v3/include/bits/stl_bvector.h.long	Fri May 31 11:35:24 2002
+++ libstdc++-v3/include/bits/stl_bvector.h	Fri May 31 11:35:36 2002
@@ -166,7 +166,7 @@
   _Bit_iterator(_Bit_type * __x, unsigned int __y) 
     : _Bit_iterator_base(__x, __y) {}
 
-  reference operator*() const { return reference(_M_p, 1U << _M_offset); }
+  reference operator*() const { return reference(_M_p, 1UL << _M_offset); }
   iterator& operator++() {
     _M_bump_up();
     return *this;
@@ -223,7 +223,7 @@
     : _Bit_iterator_base(__x._M_p, __x._M_offset) {}
 
   const_reference operator*() const {
-    return _Bit_reference(_M_p, 1U << _M_offset);
+    return _Bit_reference(_M_p, 1UL << _M_offset);
   }
   const_iterator& operator++() {
     _M_bump_up();
>Release-Note:
>Audit-Trail:
>Unformatted:

Re: libstdc++/6886: bit vector iterator uses wrong 1 constant

[pme]

Synopsis: bit vector iterator uses wrong 1 constant

Responsible-Changed-From-To: unassigned->pme
Responsible-Changed-By: pme
Responsible-Changed-When: Fri May 31 17:37:28 2002
Responsible-Changed-Why:
    I changed it.
State-Changed-From-To: open->closed
State-Changed-By: pme
State-Changed-When: Fri May 31 17:37:28 2002
State-Changed-Why:
    I've applied the patch for 3.1.1 and 3.2.
    
    This of course won't be detectable on systems where
    unsigned and unsigned long are the same size, which
    is why it's gone undetected so long.  The testcase
    you gave has been added to the v3 testsuite.
    
    Thanks.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6886