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<div class="moz-cite-prefix">On 10/27/2017 03:12 PM, Reid Kleckner
wrote:<br>
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cite="mid:CACs=ty+Ed2Z2fePG-+=jUQgd6z15kU-yWKdUoU-TGzMfzf8AAA@mail.gmail.com"
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<div class="gmail_quote">On Fri, Oct 27, 2017 at 1:08 PM, Hal
Finkel <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:hfinkel@anl.gov" target="_blank">hfinkel@anl.gov</a>></span>
wrote:<br>
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<p>On 10/27/2017 02:51 PM, Reid Kleckner wrote:<br>
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<div>Personally, I don't like the side effect
intrinsic.</div>
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</span> Understood. I also don't like the fact that it
will clutter the IR in many cases.<span class=""><br>
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<div> It will pollute all the IR generated by
non-C frontends. What most of these frontends
really want is just a switch to disable a
targeted set of optimizations.</div>
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One thing I like about the function attribute idea
is that it's conservatively correct to discard it
when doing cross-language inlining. It just
becomes something that C-family frontends need to
remember to add to enable their special-case
language rules, rather than something that non-C
languages need to think about. Similar to the
'access', builtin vs nonbuiltin discussion
happening in parallel, the attribute enables the
optimization, rather than inhibiting it.</div>
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<br>
</span> As I said below, a function attribute is
insufficient. It needs to be something we can mark per
loop. This is needed to correctly model C. The
sideeffect intrinsic is the best proposal I've seen so
far.</div>
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<div>Maybe we should do both? If the intrinsic is a special
case, that seems fine. It's cheap.</div>
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Okay.<br>
<br>
-Hal<br>
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<pre class="moz-signature" cols="72">--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre>
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