std: sysatomics: fix use of atomicCompareExchangeN for MSVC #25325
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InterlockedCompareExchange64 (winnt.h) is used instead of gcc atomics when compiling with MSVC on Windows, but the function signatures are InterlockedCompareExchange64(ptr int64, int64, int64) and InterlockedCompareExchange32(ptr int32, int32, int32) as opposed to (ptr T, ptr T, T) for __atomic_compare_exchange_n. Passing a pointer to the expected value instead of the value itself causes the comparison to unconditionally fail, with stalls in threaded code using atomic comparisons. Fix the function signature for MSVC. Signed-off-by: Ryan Walklin <[email protected]>
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Thanks for your hard work on this PR! Hint: mm: orc; opt: speed; options: -d:release |
narimiran
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`InterlockedCompareExchange64 `(winnt.h) is used instead of gcc atomics when compiling with MSVC on Windows, but the function signatures are `InterlockedCompareExchange64(ptr int64, int64, int64)` and `InterlockedCompareExchange32(ptr int32, int32, int32)` as opposed to `(ptr T, ptr T, T)` for `__atomic_compare_exchange_n`. Passing a pointer to the expected value (parameter two) instead of the value itself causes the comparison to unconditionally fail, with stalls in threaded code using atomic comparisons. Fix the function signature for MSVC. Signed-off-by: Ryan Walklin <[email protected]> (cherry picked from commit 2d0b62a)
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InterlockedCompareExchange64(winnt.h) is used instead of gcc atomics when compiling with MSVC on Windows, but the function signatures areInterlockedCompareExchange64(ptr int64, int64, int64)andInterlockedCompareExchange32(ptr int32, int32, int32)as opposed to(ptr T, ptr T, T)for__atomic_compare_exchange_n.Passing a pointer to the expected value (parameter two) instead of the value itself causes the comparison to unconditionally fail, with stalls in threaded code using atomic comparisons.
Fix the function signature for MSVC.