Compiling to 68K processor (Maybe GDC?)

[Johan Engelen]

On Saturday, 19 January 2019 at 17:45:41 UTC, Patrick Schluter 
wrote:
> Afaict NULL pointer derefernecing must fault for D to be 
> "usable". At least all code is written with that assumption.

Dereferencing `null` in D is implementation defined 
(https://dlang.org/spec/arrays.html#pointers).

For LDC, dereferencing `null` invokes Undefined Behavior [1]. 
However, the compiler does try to be a little friendly towards 
the programmer. UB includes just ignoring the dereference, but if 
you are blatantly dereferencing `null` with optimization enabled, 
the compiler generates a `ud2` instruction for you:
https://d.godbolt.org/z/5VLjFt

-Johan

[1] Now I am not quite sure yet whether Undefined Behavior is 
part of the set of behaviors allowed to choose from for 
Implementation Defined behavior. ;-)