std::stack corrupts return value

Question

I've reduced my code to the following to illustrate my problem:

#include <iostream>
#include <stack>
#include <utility>

std::pair<double,double> test(double a, double b)
{
    std::stack<int> my_stack;
    return std::make_pair<double,double>(a,b);
}

int main()
{
    std::pair<double,double> p = test(1.1,2.2);
    std::cout << p.first << " " << p.second << "\n";

    return 0;
}

The return value from the test() function gets corrupted when I use the gcc -O1 flag. Here is some sample output:

$ gcc -O2 a.cxx  -lstdc++
$ ./a.out
1.1 2.2
$ gcc -O1 a.cxx  -lstdc++
$ ./a.out
2.60831e-317 2.60657e-317
$ gcc -v
Reading specs from /usr/lib64/gcc-lib/x86_64-suse-linux/3.3.3/specs
Configured with: ../configure --enable-threads=posix --prefix=/usr --with-local-    prefix=/usr/local --infodir=/usr/share/info --mandir=/usr/share/man --enable-languages=c,c++,f77,objc,java,ada --disable-checking --libdir=/usr/lib64 --enable-libgcj --with-gxx-include-dir=/usr/include/g++ --with-slibdir=/lib64 --with-system-zlib --enable-shared --enable-__cxa_atexit x86_64-suse-linux Thread model: posix
gcc version 3.3.3 (SuSE Linux)

This code works with all gcc optimazation flags except "-O1". It also works if I remove the declaration of my_stack. Would you classify this as a compiler bug, or am I missing something about std::stack and returning std::pair values?

Answer 1

Definitely a compiler bug. BTW it is not reproduced with my GCC version (4.4.5).

The version of GCC 3.3.3 shipped with SuSE 9.1 is known to be broken (see here).