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Date:   Mon, 14 Jun 2021 17:35:45 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Kees Cook <keescook@chromium.org>
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Subject: Re: [PATCH v9] pgo: add clang's Profile Guided Optimization
 infrastructure
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On Mon, Jun 14, 2021 at 08:26:01AM -0700, Kees Cook wrote:
> So, AFAICT, the original blocking issue ("PGO does not respect noinstr")
> is not actually an issue (noinstr contains notrace, which IS respected
> by PGO[2]), I think this is fine to move forward.

It is *NOT*: https://godbolt.org/z/9c7xdvGd9

Look at how both compilers generate instrumentation in the no_instr()
function.