Internal compiler error

[menwald at starkinvestments dot com (Mat Enwald)]

GCC version:  2.95.2
System Type:  SunOS 5.7 (sparc Ultra)

Source code (main.cpp)
#include <stdlib.h>
#include <stdio.h>
int main (void)
{
    char s1 [1000];
    do
    {
        ;
    } while (s1 != NULL);

    return 0;
}

command:
/usr/local/bin/c++ -c -O main.cpp

output:
main.cpp: In function `int main()':
main.cpp:12: Internal compiler error.
main.cpp:12: Please submit a full bug report.
main.cpp:12: See
<URL:http://www.gnu.org/software/gcc/faq.html#bugreport> for
instructions.
*** Error code 1
make: Fatal error: Command failed for target `main.o'

The compile is successful without the -O parameter or without the
do/while.