[cfe-dev] Compile-time ternary operator

[Anton Bachin]

Hello,

I am making use of the ternary operator (?:) in a compile-time computation. An illustrative example:

constexpr int array[] = {1};
constexpr int value = true ? array[0] : array[-1];

int main()
{
    return 0;
}

In the actual program, the condition determines whether it is safe to perform the access in the false-case.

Clang fails to compile this program, complaining about the out-of-bounds access in the false-case. This is the case with clang++ 3.1 on BSD and OS X.

GCC 4.7 compiles the program just fine.

Is this a bug or the intent? If it's a bug, has it been fixed in 3.2?

Thank you,
Anton