[Bug target/94649] 16-byte aligned atomic_compare_exchange doesn not generate cmpxcg16b on x86_64

[marekr22 at wp dot pl via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94649

Marek Ruszczak <marekr22 at wp dot pl> changed:

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                 CC|                            |marekr22 at wp dot pl

--- Comment #8 from Marek Ruszczak <marekr22 at wp dot pl> ---
I see some regression between gcc 6.5 and 7.1
https://godbolt.org/z/n1hzKfP61

I was doing this experiments when watching this cppcon:
https://youtu.be/ZQFzMfHIxng?t=1762