Aliasing issue with TAILQ on ppc64 ?

[Poul-Henning Kamp]

In message <20120918164826.GI37286 at deviant.kiev.zoral.com.ua>, Konstantin Belou
sov writes:

>[...] compiler must not reorder accesses which
>provably causes change in the behaviour.

As I said, I'm not entirely sure why this goes wrong, and I didn't
feel like learning PPC64 assembler constraints just now to find out.

My understanding is that the cast from entry->head effectively
obscures from the compiler what goes on in this case, making that
optimization fair game.


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