IBT/BTI instructions and D compilers

[Richard (Rikki) Andrew Cattermole]

Ooooo are we challenging you to things that dmd-be can't possibly 
support and you proving us wrong?

Okay, I'll begin: dmd-be cannot support atomics as intrinsics. How do I 
know this? You're too clever to have not implemented it if it was 
possible and instead had to rely on the slow non-inlining memory 
segfaulting inline assembly instead. After all, if ldc and gdc both 
support it and dmd doesn't, it must be because it can't do it!