libstdc++/7076: iostreams very slow compared with earlier gcc versions

[morten@wtf.dk]

>Number:         7076
>Category:       libstdc++
>Synopsis:       iostreams very slow compared with earlier gcc versions
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jun 19 05:46:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Morten Brix Pedersen
>Release:        gcc-3.1
>Organization:
>Environment:

>Description:
'cout' is very slow in g++ 3.1 compared with g++ 2.95.4 (Debian prerelease).

My results with 'time', gcc 2.95.4:

mbp:~/testcode$ time ./stream > /dev/null

real    0m1.886s
user    0m0.940s
sys     0m0.000s

My results with gcc 3.1.0:

mbp:~/testcode$ time ./stream-3.1 > /dev/null

real    0m37.636s
user    0m18.520s
sys     0m0.010s


>How-To-Repeat:
#include <iostream>

int main(int argc, char** argv) 
{
    for(int i=0; i< 1500000; i++)
        std::cout << i << '\n';
} 
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: