[Bug c++/16791] New: comparison test for enum values fails when optimized

["thiessen at ncbi dot nlm dot nih dot gov" <gcc-bugzilla at gcc dot gnu dot org>]

This looks a lot like bug #15069, which was marked fixed for 3.4.1 (as far as I 
can tell - I'm new to GCC Bugzilla). However, I'm using GCC 3.4.1 on linux, and 
I'm seeing a problem with the code:

#include <iostream>
using namespace std;

  // atom type
  enum eAtomClassification {
    eSideChainAtom,
    eAlphaBackboneAtom,
    ePartialBackboneAtom,
    eCompleteBackboneAtom,
    eUnknownAtom
  };

int main(int argc, char **argv)
{
  eAtomClassification classification = eUnknownAtom;

  if ((classification == eAlphaBackboneAtom) ||
      (classification == ePartialBackboneAtom) ||
      (classification == eCompleteBackboneAtom))
  {
    cout << "error:\n";
    cout << "class " << classification << "\n" << flush;
    cout << eAlphaBackboneAtom << " "
         << ePartialBackboneAtom
         << " " << eCompleteBackboneAtom << "\n" << flush;
    return 1;
  }

  cout << "okay\n";
  return 0;
}

When compiled with optimization, it doesn't execute properly:

(trans)(~/tmp) g++ -O1 -o gcc-bug-2 gcc-bug-2.cpp
(trans)(~/tmp) gcc-bug-2
error:
class 4
1 2 3
(trans)(~/tmp) g++ -O2 -o gcc-bug-2 gcc-bug-2.cpp
(trans)(~/tmp) gcc-bug-2
error:
class 4
1 2 3
(trans)(~/tmp) g++ -O0 -o gcc-bug-2 gcc-bug-2.cpp
(trans)(~/tmp) gcc-bug-2
okay

Is this the same bug #15069, or is it something different? In any case, it's not 
working in 3.4.1... My version:

(trans)(~/tmp) g++ -v
Reading specs from /usr/lib/gcc-3.4.1/gcc/i686-pc-linux-gnu/3.4.1/specs
Configured with: ./configure --prefix=/usr/local/gcc-3.4.1 
--libdir=/usr/lib/gcc-3.4.1 --with-include=/usr/local/gcc-3.4.1/include 
--enable-threads --enable-shared --enable-languages=c,c++,f77,java 
--with-gxx-include-dir=/usr/local/gcc-3.4.1/include/g++-v3
Thread model: posix
gcc version 3.4.1

-- 
           Summary: comparison test for enum values fails when optimized
           Product: gcc
           Version: 3.4.1
            Status: UNCONFIRMED
          Severity: critical
          Priority: P1
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: thiessen at ncbi dot nlm dot nih dot gov
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16791