Why 16Mib static array size limit?

[Walter Bright via Digitalmars-d]

On 8/15/2016 6:28 PM, Ali Çehreli wrote:
> void main() {
>     auto p = arr.ptr;
>
>     foreach (j; 0 .. 100) {
>         foreach (i; 0..arr.length) {
>             version (POINTER) {
>                 p[i] += cast(ubyte)i;
>             }
>             else {
>                 arr[i] += cast(ubyte)i;
>             }
>         }
>     }
> }

When accessing global arrays like this, cache the address of the data in a local 
variable. This will enable the compiler to enregister it. Putting global data in 
registers is problematic because any assignment through a pointer could change 
it, so the compiler takes a pessimistic view of it.

Your POINTER version does cache the pointer, but arr.length needs to be cached 
as well.