[Bug c++/29597] New: log expression returns different results when casting

["brad_atcheson at yahoo dot ca" <gcc-bugzilla at gcc dot gnu dot org>]

The following code should return the base2 logarithm of 64 (ie 6)

double d = log(64.0) / log(2.0);
int i = (int)d;
cout << i;

And indeed it does output "6". However, if you attempt to cast it on the same
line, then it returns 5.

int i2 = (int)( log(64.0) / log(2.0) );
int i3 = static_cast<int>( log(64.0) / log(2.0) );
cout << i2 << i3;

This outputs "55" instead of the expected "66". Visual Studio 2003 outputs
"66".

gcc 4.1.0, Suse Linux 10.1.


-- 
           Summary: log expression returns different results when casting
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: brad_atcheson at yahoo dot ca


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29597