🚀 go-pugleaf

OK, so I have this code:

void TBlockStreamDocument::ReserveDiskSpace(long long &requestedSpace)
{
    HParamBlockRec pb;
    long long freeBytes;

    BlockZero_AC(pb);

    if (fDocStream->GetFile()->GetVolumeInfo(pb) == noErr)
    {
        // pb.*.* are both unsigned longs that return the amount
        // of free disk blocks and the size of these blocks, respectively.

        long long ioVFrBlk = pb.volumeParam.ioVFrBlk;
        long long ioVAlBlkSiz = pb.volumeParam.ioVAlBlkSiz;
        freeBytes = ioVFrBlk * ioVAlBlkSiz;
    }
    else
        freeBytes = 0;
    
    if (freeBytes < requestedSpace)
        requestedSpace = 0;
}

In my debug version of this app (optimization level 0), this works as
expected. In my release version (optimization level 4), this function sets
requestedSpace to 0 every time, because freeBytes always is set to 0. During
debugging, I can see that the "if" block is always executed in both the
release and debug versions. However, if I look at the variables window, in
the debug version, I can see where freeBytes is set to the appropriate value
in the debug version. But in the release version, the "value" of freeBytes
according to the debugger is  "*Buffer for SetVariable must be exact size of
variable*"

WTF?

No idea what that is supposed to mean. But coming out of the "if" block,
freeBytes is always 0 in the release version, but it's set to the correct
value in the debug version under identical circumstances.

If I change all of the long longs in this example to plain old longs, it
works. Which would be an OK solution, except that these days, a 32 bit int
isn't big enough to store the number of free bytes someone might have
available on their hard disk.

Is this an optimization bug, or am I missing something simple here?