Update comments now that LLVM PR3861 has been fixed. However, since conditionally removing the workaround makes the ABI dependent on LLVM version, I reconsidered that. (The same revision of LDC compiling for the same target should probably produce code that follows the same ABI, right?)

module bug51;
const ubyte[3] arr1 = 1;
const ubyte[3] arr2 = [1];
const ubyte[3] arr3 = [1:1];
void main()
{
    assert(arr1 == [cast(ubyte)1,1,1][]);
    assert(arr2 == [cast(ubyte)1,0,0][]);
    assert(arr3 == [cast(ubyte)0,1,0][]);
}