Fix atomic_ref::is_lock_free() on x64
#4729
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For `!_ATOMIC_HAS_DCAS`: If we're `is_always_lock_free` (power of two, at most 1 pointer), return true. Otherwise, we have to be `_Is_potentially_lock_free` (power of two, at most 2 pointers) and have cmpxchg16b.
Co-authored-by: Alex Guteniev <[email protected]>
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I'm speculatively mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed. |
barcharcraz
approved these changes
Jun 27, 2024
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Fixes #4728.
For
!_ATOMIC_HAS_DCAS:is_always_lock_free(power of two, at most 1 pointer), return true._Is_potentially_lock_free(power of two, at most 2 pointers) and have cmpxchg16b.