[PATCH] D46386: Adding __atomic_fetch_min/max intrinsics to clang

[John McCall via Phabricator via cfe-commits]

rjmccall added inline comments.


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Comment at: docs/LanguageExtensions.rst:1998
+``__ATOMIC_CONSUME``, ``__ATOMIC_ACQUIRE``, ``__ATOMIC_RELEASE``,
+``__ATOMIC_ACQ_REL``, or ``__ATOMIC_SEQ_CST`` following C++11 memory model semantics.
+
----------------
Thank you for adding this documentation.  Please do clarify what the memory ordering semantics actually are when the atomic object does not need to be updated, though, and verify that target code generation actually obeys that ordering.  For example, if the memory ordering makes this a release operation, `__atomic_fetch_min` must always store the result back to the atomic object, even if the new value was actually greater than the stored value; I believe that would not be required with a relaxed operation.


Repository:
  rC Clang

https://reviews.llvm.org/D46386