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Subject: [Bug target/55966] __atomic_fetch_* generate wrong code for HLE
Date: Mon, 14 Jan 2013 22:05:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55966

--- Comment #6 from Andi Kleen <andi-gcc at firstfloor dot org> 2013-01-14 22:05:38 UTC ---
Hmm that's true. x86 doesn't have xand, x_or, x_xor, only xadd 
Maybe cmpxchg is the only way?

For some special cases it can be done (like and single bit-> btr, or single bit
-> btr), but it's probably complicated to implement.

In this case I would prefer to forbid those for HLE.
I guess more arguments for the target hook.

Other ideas?