Constant time compares when array sizes are not equal?

What is the preferred or recommended way to pursue contestant time compares when array lengths are not equal?

Should we exit as early as possible? Something like:

if (array1.size() != array2.size()) {
    return NOT_EQUAL;
}

int accum = 0;
for(int i = 0; i < array1.size(); i++) {
    accum |= array1[i] ^ array2[i];
}

return (accum == 0) ? EQUAL : NOT_EQUAL;

Or should we avoid the early exit, and compare as much as possible in hopes of masking as much as possible? Something like:

int size = min(array1.size(), array2.size());
int accum = (array1.size() ^ array2.size());

for(int i = 0; i < size; i++) {
    accum |= array1[i] ^ array2[i];
}

return (accum == 0) ? EQUAL : NOT_EQUAL;

Or something else?

Or is this question more appropriate for the folks on the Crypto.SE because its theoretical minutia?