[Issue 20838] on modern (x86_64) CPUs, dmd emit cmpxchg8b instead of CMPXCHG16B

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20838

--- Comment #13 from mw <mingwu at gmail.com> ---
> you need to manually take care of required 16-bytes alignment:
> align(16) shared(N) n; // or `align(2 * size_t.sizeof)`

Thank you again!

(I'm a newbie to D, not sure where is the best place to continue discuss this?
pls let me know.)


BUT: can the DMD compiler (after seeing the 'cas' call) take care of this
alignment? either silently, or issue an warning message to the programmer?

Can I log another bug for this suggestion of DMD compiler improvement?

The current behavior that I just discovered is definitely a puzzle for a D
newbie like me. With a smarter compiler, it will help new users.

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