Replying to mark@…:
Replying to dsteffen@…:
+#define dispatch_atomic_barrier() \ + asm volatile("" : : : "memory")
This assembly instruction won't work on ARM or PPC, according to a similar function in the Haskell source code[1] as reproduced below:
no, this would double up the generated barrier instructions, the __sync builtins are defined to already include these on architectures where necessary (the libdispatch arm port is not open-source, but does do the right thing here).