[PATCH] D18164: [tsan] Do not instrument reads/writes to instruction profile counters.

[Xinliang David Li via llvm-commits]

On Tue, Mar 15, 2016 at 10:43 AM, Anna Zaks <zaks.anna at gmail.com> wrote:

> zaks.anna added a comment.
>
> dvyukov's point is that there are no "benign races" based on LLVM
> semantics. People might argue that their race is benign because it will
> result in atomic reads/writes on the architectures they care about.


It is not about this assumption, but more about racy counter updates not
being a problem practically  (other than the precision of the profile data
might be affected slightly in practice).

David


> However, in that case, they should annotate their loads and stores as
> atomic explicitly, which would lower to no-op on the architectures they
> care about but will also be modeled correctly at the LLVM level. (TSan's
> pass reasons about LLVM semantics.) This is why I suggested to use
> "Monotonic". (http://llvm.org/docs/Atomics.html#id10)
>




>
>
> http://reviews.llvm.org/D18164
>
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>
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