[PATCH] D22557: [libcxx] Diagnose invalid memory order arguments in <atomic>. Fixes PR21179.

[JF Bastien via cfe-commits]

jfb added inline comments.

================
Comment at: include/atomic:569
@@ +568,3 @@
+    __attribute__ ((__enable_if__(__m == memory_order_release                 \
+                               || __m == memory_order_acq_rel, "")))          \
+    __attribute__ ((__unavailable__("memory order argument to atomic operation is invalid")))
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bcraig wrote:
> what about relaxed?
Load relaxed is valid.


https://reviews.llvm.org/D22557