Re: libstdc++/40: bitset::operator<<= and >>= incorrect for multiplesof 32

[Benjamin Kosnik <bkoz at cygnus dot com>]

The following reply was made to PR libstdc++/40; it has been noted by GNATS.

From: Benjamin Kosnik <bkoz@cygnus.com>
To: anders@ieee.org
Cc: libstdc++-gnats@sourceware.cygnus.com, libstdc++-prs@sourceware.cygnus.com
Subject: Re: libstdc++/40: bitset::operator<<= and >>= incorrect for multiples
 of 32
Date: Fri, 10 Mar 2000 11:17:48 -0800 (PST)

 can you please send me a patch and change log entry?
 
 thanks,
 benjamin
 
 
 On 10 Mar 2000 anders@ieee.org wrote:
 
 > 
 > >Number:         40
 > >Category:       libstdc++
 > >Synopsis:       bitset::operator<<= and >>= incorrect for multiples of 32
 > >Confidential:   no
 > >Severity:       serious
 > >Priority:       medium
 > >Responsible:    unassigned
 > >State:          open
 > >Class:          sw-bug
 > >Submitter-Id:   net
 > >Arrival-Date:   Thu Mar 09 20:57:00 PST 2000
 > >Closed-Date:
 > >Last-Modified:
 > >Originator:     Anders Johnson
 > >Release:        libstdc++-2.90.7
 > >Organization:
 > >Environment:
 > SunOS thresher 5.6 Generic_105181-05 sun4u sparc SUMW,Ultra-60
 > >Description:
 > The implementation of bitset relies on the behavior
 > of _WordT >> __BITS_PER_WORDT(_WordT), which is not
 > defined according to the C standard, and is equivalent
 > to _WordT >> 0 on the Sparc. This occurs whenever the
 > shift amount is a multiple of __BITS_PER_WORDT(_WordT).
 > >How-To-Repeat:
 > 
 > >Fix:
 > The expressions on lines 201 and 220 of stl/bits/std_bitset.h
 > should read (__offset ? ... : static_cast<_WordT>(0)) instead.
 > >Release-Note:
 > >Audit-Trail:
 > >Unformatted:
 >