[Bug target/80878] -mcx16 (enable 128 bit CAS) on x86_64 seems not to work on 7.1.0

[andysem at mail dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80878

andysem at mail dot ru changed:

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                 CC|                            |andysem at mail dot ru

--- Comment #9 from andysem at mail dot ru ---
The docs
(https://gcc.gnu.org/onlinedocs/gcc-7.2.0/gcc/_005f_005fatomic-Builtins.html#g_t_005f_005fatomic-Builtins)
still says that `__atomic` builtins are intended to replace `__sync` builtins
and should be preferred in the new code. This is no longer true as `__sync`
builtins are now the only way to generate cmpxchg16b without having to write
assembler code. Please, update the docs accordingly.