[Bug c++/27647] New: Different results depending on optimization level with gcc-4.0.1

[scharest at druide dot com]

I'm not sure if this is the right place to send this bug to. I sent this bug to
Apple on March 2nd, 2006, but the bug is still open in their database as of
today (May 17th).

Here's the description:

I've noticed a different behavior of my application depending on whether I
turned optimization on or off in XCode 2.2 using gcc-4.0.1. I managed to make
the code as simple as possible to still reproduce the problem. With the
following code, in a standard C++ tool project in XCode, I get a result of 1
without optimization (expected result), but a result of 0 with optimization -O1
(bad result). I'm running on a dual G5 PPC. I'm compiling for PPC. 

#include <iostream>

static bool func2(bool bool1, bool bool2)
{
        if (bool1 == bool2)
                return true;
        else
                return false;
}

bool func1(unsigned long arg1, unsigned long arg2)
{
        return (func2(!(arg1 & 1), !(arg2 & 1)) && !(arg1 & 1));
}

int main (int argc, char * const argv[])
{
        bool result = func1(0, 0);

        std::cout << "result = " << result << "\n";
        return 0;
}


-- 
           Summary: Different results depending on optimization level with
                    gcc-4.0.1
           Product: gcc
           Version: 4.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: scharest at druide dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27647